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The present study examined the regulatory mechanism of hydrogen sulfide (H2S) and nitric oxide (NO) in nickel (Ni) stressed cyanobacteria viz., Nostoc muscorum and Anabaena sp. by analyzing growth, photosynthetic pigments, biochemical components (protein and carbohydrate), exopolysaccharides (EPS), inorganic nitrogen content, and activity of enzymes comprised in nitrogen metabolism and Ni accumulation. The 1 µM Ni substantially diminished growth by 18% and 22% in N. muscorum and Anabaena sp. respectively, along with declining the pigment contents (Chl a/Car ratio and phycobiliproteins), and biochemical components. It also exerted negative impacts on inorganic uptake of nitrate and nitrite contents; nitrate reductase and nitrite reductase; and ammonium assimilating enzymes (glutamine synthetase, glutamate synthase, and glutamate dehydrogenase exhibited a reverse trend) activities. Nonetheless, the adverse impact of Ni can be mitigated through the exogenous supplementation of NaHS [sodium hydrosulfide (8 µM); H2S donor] and SNP [sodium nitroprusside (10 µM); NO donor] which showed substantial improvement on growth, pigments, nitrogen metabolism, and EPS layer and noticeably occurred as a consequence of a substantial reduction in Ni accumulation content which minimized the toxicity effects. The accumulation of Ni on both the cyanobacterial cell surface (EPS layer) are confirmed by the SEM–EDX analysis. Further, the addition of NO scavenger (PTIO; 20 µM) and inhibitor of NO (L-NAME; 100 µM); and H2S scavenger (HT; 20 µM) and H2S inhibitor (PAG; 50 µM) reversed the positive responses of H2S and NO and damages were more prominent under Ni stress thereby, suggesting the downstream signaling of H2S on NO-mediated alleviation. Thus, this study concludes the crosstalk mechanism of H2S and NO in the mitigation of Ni-induced toxicity in rice field cyanobacteria. [ABSTRACT FROM AUTHOR]

Hepatitis A virus (HAV) infects humans and nonhuman primates, typically causing an acute self-limited illness. Three HAV genotypes have been described so far for humans, and three genotypes have been described for nonhuman primates. We observed transiently elevated liver enzymes in Mauritius-origin laboratory-housed macaques in Germany and were not able to demonstrate an etiology including HAV by serology and polymerase chain reaction (PCR). HAV is a rare pathogen in cynomolgus macaques, and since all employees were routinely vaccinated against HAV, it was not a part of the routine vaccination and screening program. A deep sequencing approach identified a new HAV genotype (referred to as Simian_HAV_Macaca/Germany/Mue-1/2022) in blood samples from affected animals. This HAV was demonstrated by reverse transcription PCR in blood and liver and by in situ hybridization in liver, gall bladder, and septal ducts. A commercial vaccine was used to protect animals from liver enzyme elevation. The newly identified simian HAV genotype demonstrates 80% nucleotide sequence identity to other simian and human HAV genotypes. There was deeper divergence between Simian_HAV_Macaca/Germany/Mue-1/2022 and other previously described HAVs, including both human and simian viruses. In situ hybridization indicated persistence in the biliary epithelium up to 3 months after liver enzymes were elevated. Vaccination using a commercial vaccine against human HAV prevented reoccurrence of liver enzyme elevations. Because available assays for HAV did not detect this new HAV genotype, knowledge of its existence may ameliorate potential significant epidemiological and research implications in laboratories globally. [ABSTRACT FROM AUTHOR]

There are two paralogs of glutamate dehydrogenase (GDH) in humans encoded by the GLUD1 and GLUD2 genes as a result of a recent retroposition during the evolution of primates. The two human GDHs possess significantly different regulation by allosteric ligands, which is not fully characterized at the structural level. Recent advances in identification of the GDH ligand binding sites provide a deeper perspective on the significance of the accumulated substitutions within the two GDH paralogs. In this review, we describe the evolution of GLUD1 and GLUD2 after the duplication event in primates using the accumulated sequencing and structural data. A new gibbon GLUD2 sequence questions the indispensability of ancestral R496S and G509A mutations for GLUD2 irresponsiveness to GTP, providing an alternative with potentially similar regulatory features. The data of both GLUD1 and GLUD2 evolution not only confirm substitutions enhancing GLUD2 mitochondrial targeting, but also reveal a conserved mutation in ape GLUD1 mitochondrial targeting sequence that likely reduces its transport to mitochondria. Moreover, the information of GDH interactors, posttranslational modification and subcellular localization are provided for better understanding of the GDH mutations. Medically significant point mutations causing deregulation of GDH are considered from the structural and regulatory point of view. [ABSTRACT FROM AUTHOR]

This study was designed with the objective of comparing three different plant growth regulators, putrescine (Put), meta-topolin (mT), and 24-epibrassinolide (EBL), in affecting cucumber plants under salt stress. The pilot assessment revealed that all treatments had a significant effect (P < 0.05) on vegetative traits, seedling vigor, total chlorophyll content, and root activity compared to control. The treatment T5 showed the greatest numbers in regard to the above–mentioned traits compared with other combinations. The salt stress study reported that T2 increased superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) activities in leaves by 31%, 4.4%, 22.4%, and 35.2%, respectively, in comparison with the control. On the other hand, S3 markedly increased antioxidant enzyme activities, and the activity level was significantly higher than the control and salt treatment. Exogenous S3 had a highly significant effect on glutamine synthetase (GS), glutamate synthase (GOGAT), and (GDH), glutamate dehydrogenase activities in leaves and roots compared with T2. Application of S3 had a highly significant effect on sucrose synthase (SS) and sucrose phosphate synthase (SPS) under salinity stress in leaves and roots compared with other salt stress treatments. The results showed that (5 mM Put + 0.002 ppm mT + 0.001 ppm EBR) treatment alleviated the growth inhibition caused by salt stress by regulating the C-N enzyme activities in cucumber plants. [ABSTRACT FROM AUTHOR]

Enhancing Nitrogen Use Efficiency (NUE) is extremely important towards mitigating climate change, especially in wheat where the NUE is less than 50%. Hence, optimizing grain yield under reduced application of nitrogenous fertilizer is a significant challenge. To address this challenge, a comprehensive study was conducted to investigate various agronomic traits and morphological, biochemical and molecular parameters related to NUE. This study explored their interrelationships and effects on grain yield, providing novel insights that were not previously reported. A set of 278 diverse wheat genotypes were assessed, encompassing eight NUE‐related field traits. All traits' values were reduced under stressed N (ranging from 7.5% to 77.5%) except Nitrogen Utilization Efficiency (NUtE) and NUE. Data analysis showed a significant positive correlation between grain yield and all other NUE‐related traits (r2 value ranged from.23 to 1.00), highlighting their relevance in comprehending the biological NUE of wheat plants. Principal component analysis (PCA) also revealed that N at head and N at harvest were more connected with gain yield, NUE and biomass under the optimum N condition, but less connected with gain yield and NUE under the stressed N condition. To complement the field data, representative genotypes were further subjected to a hydroponics experiment under absolute N control to study the different morphological parameters, photosynthetic pigments and the performance of essential N‐ and C‐metabolizing enzymes at the seedling stage. N stress had a detrimental impact on the majority of the parameters (−0.84% to −79.8%). Nitrite reductase (NiR), glutamate dehydrogenase (GDH) and isocitrate dehydrogenase (ICDH) enzymes as well as root length (RL), root fresh weight (RFW) and CS transcript, were positively affected by 5.9%–35.6%. The correlation analysis highlighted the substantial influence of four key N‐metabolizing enzymes, namely nitrate reductase (NR), glutamine synthetase (GS), glutamate oxo‐glutarate aminotransferase (GOGAT), and GDH on grain yield. Additionally, this study highlighted the direct and indirect associations between seedling parameters and field traits, where shoot and root length were found to be most significant for N acquisition, especially under N stress. In conclusion, these findings offer valuable insights into the intricate network of traits and parameters influencing wheat grain yield under varying N regimes. [ABSTRACT FROM AUTHOR]

Candida albicans has the capacity to neutralize acidic growth environments by releasing ammonia derived from the catabolism of amino acids. The molecular components underlying alkalization and its physiological significance remain poorly understood. Here, we present an integrative model with the cytosolic NAD+‐dependent glutamate dehydrogenase (Gdh2) as the principal ammonia‐generating component. We show that alkalization is dependent on the SPS‐sensor‐regulated transcription factor STP2 and the proline‐responsive activator Put3. These factors function in parallel to derepress GDH2 and the two proline catabolic enzymes PUT1 and PUT2. Consistently, a double mutant lacking STP2 and PUT3 exhibits a severe alkalization defect that nearly phenocopies that of a gdh2‐/‐ strain. Alkalization is dependent on mitochondrial activity and in wild‐type cells occurs as long as the conditions permit respiratory growth. Strikingly, Gdh2 levels decrease and cells transiently extrude glutamate as the environment becomes more alkaline. Together, these processes constitute a rudimentary regulatory system that counters and limits the negative effects associated with ammonia generation. These findings align with Gdh2 being dispensable for virulence, and based on a whole human blood virulence assay, the same is true for C. glabrata and C. auris. Using a transwell co‐culture system, we observed that the growth and proliferation of Lactobacillus crispatus, a common component of the acidic vaginal microenvironment and a potent antagonist of C. albicans, is unaffected by fungal‐induced alkalization. Consequently, although Candida spp. can alkalinize their growth environments, other fungal‐associated processes are more critical in promoting dysbiosis and virulent fungal growth. [ABSTRACT FROM AUTHOR]

This study investigated the effect of oral bovine serum albumin (BSA) on plasma amino acid profile and growth performance in blunt snout bream fed high‐fat and high‐energy diets. A total of 360 fish (average weight: 45.84 ± 0.07 g) were randomly divided into three groups in four replicates and fed with the control, high‐fat diet (HFD), and high‐energy diet (HED), respectively. After 12 weeks of feeding, fish were orally administered with 10% BSA for 10 h, with the blood and liver sample obtained at 10 h. The results showed no remarkable difference (p > 0.05) in final weight, weight gain rate, feed conversion ratio, protein efficiency ratio, and daily growth rate among dietary treatments. However, fish fed HFD and HED obtained significantly higher energy and nitrogen retention content than the control. Plasma valine and histidine content were more prevalent in fish fed the control diet than in HFD and HED groups. However, BSA significantly enhanced this content with higher values observed in arginine and alanine content than in control diets at 10 h. Significantly higher liver and plasma Aspartate aminotransferase, Xanthine oxidase, and Glutamate dehydrogenase content were found in the HFD than in the control group. However, the administration of BSA at 10 h improved these parameters similar to the control. Meanwhile, protease, Lipase, aminopeptidase N, carboxypeptidase A, and Na+ K+‐ATPase were influenced significantly (p < 0.001) by sampling time, dietary treatments, and their interaction. Fish fed with the HFD and HED significantly downregulated (p < 0.05) the akt, bcat2, 4e‐bp1, s6k1, and tor expression compared to the control. However, BSA administration at 10 h improved these genes similar to the control. This study indicated that oral BSA administration could benefit plasma amino acid through the TOR signaling pathway in blunt snout bream fed high‐fat and high‐energy diets. [ABSTRACT FROM AUTHOR]

Graphene has promising applications in agriculture and forestry. In the current study, six different concentrations of graphene (0mg/L, 0.01mg/L, 0.10mg/L, 1.00mg/L, 10.00mg/L, and 100.00mg/L) were used to investigate its effect on the growth and development of V. angularis plants in soil culture. The results showed that the group treated with 1.00mg/L graphene (G-1) had significantly increased plant height (19.86%), stem diameter (24.33%), and leaf area (13.69%), compared to the control group (CK). Moreover, all concentrations of graphene had positive effects on the total root length, total root surface area, and the number of root tips of V. angularis. Compared to the CK group, the G-1 group had significantly increased leaf water potential (37.89%), leaf conductivity (2.25%), and SOD, POD, and CAT activities (47.67%, 35.22%, and 199.3%, respectively). The G-1 group also showed improved leaf net photosynthetic rate, chlorophyll content, and soluble sugar content (51.28%, 24.25%, and 38.35%, respectively), compared to the CK group. Additionally, 1.00mg/L graphene led to a 23.88% increase in the podding rate and a 17.04% increase in the yield of V. angularis plants. The rhizosphere soil of V. angularis treated with 1.00mg/L graphene had a 25.14% increase in hydrolyzable nitrogen content and a 66.67% increase in available phosphorus content. RNA-seq data indicated that 1.00mg/L graphene induced the expression of photosynthesis and nitrogen transmembrane transport genes, including ATP synthase subunit b, photosystem I reaction center subunit XI, photosystem I reaction center subunit IV A, ferredoxin, and psbP-like protein 1, as well as genes for photosynthesis antenna proteins, glutamine synthetase, glutamate dehydrogenase 1, cyanate hydratase, protein fluG-like, and NRT1/PTR family, suggesting that graphene promoted the growth and development of V. angularis by enhancing the photosynthesis and nitrogen metabolism processes in V. angularis plants. Our results indicated that a suitable concentration of graphene could significantly promote the growth of V. angularis plants in soil. [ABSTRACT FROM AUTHOR]

This document is a compilation of scientific articles that discuss the emergence of land plants and their impact on the Earth's surface. It focuses on the evolution of multicellular organisms that have adapted to life on land, with a particular emphasis on streptophyte algae as the closest algal relatives to land plants. The articles explore various biochemical, physiological, and morphological characteristics that contribute to plant terrestrialization and their evolutionary history. They also examine the importance of cell wall composition and structure, as well as the role of cell signaling and stress responses in plant adaptation to harsh land conditions. The studies mentioned in the articles investigate topics such as lipid profiles during desiccation, response to salt stress, freezing tolerance, and the evolution of cytochrome P450 enzymes. They highlight the ability of streptophyte algae to adapt to different stressors and the conservation of certain characteristics in land plants and streptophyte algae. The articles also mention the development of genetic tools to further study these mechanisms. Overall, this compilation provides valuable insights into plant biology and evolution for researchers in the field. [Extracted from the article]

(1) Background: Valproic acid (VPA) is one of the frequently prescribed antiepileptic drugs and is generally considered well tolerated. However, VPA neurologic adverse effects in the absence of liver failure are fairly common, suggesting that in the mechanism for the development of VPA-induced encephalopathy, much more is involved than merely the exposure to hyperammonemia (HA) caused by liver insufficiency to perform detoxification. Taking into account the importance of the relationship between an impaired brain energy metabolism and elevated ammonia production, and based on the ability of VPA to interfere with neuronal oxidative pathways, the current study intended to investigate a potential regional ammoniagenic effect of VPA on rats' brains by determining activities of the enzymes responsible for ammonia production and neutralization. (2) Methods: Rats received a single intraperitoneal injection of VPA (50, 100, 250, 500 mg/kg). Plasma, the neocortex, the cerebellum, and the hippocampus were collected at 30 min after injection. The levels of ammonia, urea, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) were measured in blood plasma. The activities of glutaminase and glutamate dehydrogenase (GDH) in mitochondria and the activities of AMP deaminase (AMPD), adenosine deaminase (ADA), and glutamine synthetase (GS) in cytosolic fractions isolated from rat brain regions were measured. Ammonia, ALT, and AST values were determined in the mitochondrial and cytosolic fractions. (3) Results: Multi-dose VPA treatment did not significantly affect the plasma levels of ammonia and urea or the ALT and AST liver enzymes. Significant dose-independent increases in the accumulation of ammonia were found only in the cytosol from the cerebellum and there was a strong correlation between the ammonia level and the ADA activity in this brain structure. A significant decrease in the AMPD and AST activities was observed, while the ALT activity was unaffected. Only the highest VPA dose (500 mg/kg) was associated with significantly less activity of GS compared to the control in all studied brain structures. In the mitochondria of all studied brain structures, VPA caused a dose-independent increases in ammonia levels, a high concentration of which was strongly and positively correlated with the increased GDH and ALT activity, while glutaminase activity remained unchanged, and AST activity significantly decreased compared to the control in all studied brain structures. (4) Conclusions: This study highlights the rat brain region-specific ammoniagenic effects of VPA, which may manifest themselves in the absence of hyperammonemia. Further research should analyze how the responsiveness of the different brain regions may vary in VPA-treated animals that exhibit compromised energy metabolism, leading to increased ammoniagenesis. [ABSTRACT FROM AUTHOR]

There is a limited research focus on evaluating the detrimental effects of prolonged zearalenone (ZEN) intake on dairy cows' health under controlled conditions. This experiment was conducted to evaluate whether the length of exposure to a ZEN-contaminated total mixed ration (TMR) at a level of 9.45 mg per day can negatively influence animal health parameters, such as milk composition, rumen and fecal fermentation, and the chewing activity of lactating dairy cows. For this experiment, we used 18 lactating Simmental cows that were fed a diet of 60% forage and 40% concentrate (on dry matter basis) for 26 consecutive days. The first 4 days were for adaptation prior to the first sampling day (day 0). The sampling events took place on day 0 (baseline) without ZEN, followed by day 1, day 7, day 14, and day 21 (with toxin). Dry matter intake (DMI) and ruminating chews per minute increased on the third week of ZEN inclusion; meanwhile, ruminating, eating, and drinking times were not affected. Most milk composition variables were also unaffected. Rumen fluid osmolality increased on day 21 and total short-chain fatty acids (SCFA) of ruminal fluid decreased on day 7. Fecal SCFA increased on day 21 and the acetate-to-propionate ratio increased from day 1 onwards, showing the influence of toxin intake. Animal health parameters, like heart rate, respiratory rate, and body temperature, were negatively influenced by ZEN intake, all increasing consistently on days 4 and 6, 9 and 12, and 16 and 18, respectively. The liver enzyme glutamate dehydrogenase decreased in response to ZEN intake on day 7. A total daily ZEN intake at the level of 9.45 mg did not show detrimental effects on DMI. Nevertheless, certain health parameters were negatively affected, including body temperature, respiratory rate, and heart rate, starting from the 7th day of ZEN intake, with additional signs of possible loss of water balance on the last sampling day. [ABSTRACT FROM AUTHOR]

Respiratory illnesses present a significant threat to porcine health, with co-infections involving Porcine Reproductive and Respiratory Syndrome Virus (PRRSV), Streptococcus suis (SS), Porcine Circovirus Type 2 (PCV2), and Porcine Circovirus Type 3 (PCV3) acting as the primary causative agents. As a result, the precise diagnosis of PRRSV, PCV2, PCV3 and SS is of paramount importance in the prevention and control of respiratory diseases in swine. Therefore, we conducted a molecular bioinformatical analysis to concurrently detect and differentiate PRRSV, PCV2, PCV3 and SS. We selected the ORF6 gene of PRRSV, the ORF2 gene of PCV2 and PCV3, and the glutamate dehydrogenase (GDH) gene of SS as targets. Specific primers and probes were designed for each pathogen, and following meticulous optimization of reaction conditions, we established a multiple TaqMan fluorescence quantitative PCR detection method. Subsequently, we subjected this method to a comprehensive assessment, evaluating its specificity, sensitivity, and repeatability. The research results demonstrated that the established multiple TaqMan fluorescence quantitative PCR detection method displays displayed exemplary specificity, with no instances of cross-reactivity with other pathogens. The method's minimum detection concentrations for PRRSV, PCV2, PCV3, and SS were 2.80 × 101 copies/µL, 1.96 × 102 copies/µL, 2.30 × 102 copies/µL, and 1.75 × 103 copies/µL, respectively. When applied to the analysis of 30 clinical samples, the results closely mirrored those obtained through Chinese standard uniplex real-time qPCR detection method for PRRSV, as well as the general PCR methods for SS, PCV2, and PCV3. This study underscores the robust specificity, high sensitivity, and consistent stability of the multiple TaqMan fluorescence quantitative PCR detection method that we have developed. It is ideally suited to the clinical monitoring of PRRSV, PCV2, PCV3, and SS, and it carries significant importance in ongoing efforts to prevent and manage respiratory diseases in porcine populations. [ABSTRACT FROM AUTHOR]

Background: Komagataella phaffii (a.k.a. Pichia pastoris) harbors a glutamate utilization pathway in which synthesis of glutamate dehydrogenase 2 and phosphoenolpyruvate carboxykinase (PEPCK) is induced by glutamate. Glutamate-inducible synthesis of these enzymes is regulated by Rtg1p, a cytosolic, basic helix-loop-helix protein. Here, we report food-grade monosodium glutamate (MSG)-inducible recombinant protein production from K. phaffii PEPCK promoter (PPEPCK) using green fluorescent protein (GFP) and receptor binding domain of SARS-CoV-2 virus (RBD) as model proteins. Results: PPEPCK-RBD/GFP expression cassette was integrated at two different sites in the genome to improve recombinant protein yield from PPEPCK. The traditional, methanol-inducible alcohol oxidase 1 promoter (PAOX1) was used as the benchmark. Initial studies carried out with MSG as the inducer resulted in low recombinant protein yield. A new strategy employing MSG/ethanol mixed feeding improved biomass generation as well as recombinant protein yield. Cell density of 100–120 A600 units/ml was achieved after 72 h of induction in shake flask cultivations, resulting in recombinant protein yield from PPEPCK that is comparable or even higher than that from PAOX1. Conclusions: We have designed an induction medium for recombinant protein production from K. phaffii PPEPCK in shake flask cultivations. It consists of 1.0% yeast extract, 2.0% peptone, 0.17% yeast nitrogen base with ammonium sulfate, 100 mM potassium phosphate (pH 6.0), 0.4 mg/L biotin, 2.0% MSG, and 2% ethanol. Substitution of ammonium sulphate with 0.5% urea is optional. Carbon source was replenished every 24 h during 72 h induction period. Under these conditions, GFP and RBD yields from PPEPCK equaled and even surpassed those from PAOX1. Compared to the traditional methanol-inducible expression system, the inducers of glutamate-inducible expression system are non-toxic and their metabolism does not generate toxic metabolites such as formaldehyde and hydrogen peroxide. This study sets the stage for MSG-inducible, industrial scale recombinant protein production from K. phaffii PPEPCK in bioreactors. [ABSTRACT FROM AUTHOR]

In this study, we aimed to evaluate the effects of Arbuscular mycorrhiza fungus (AMF) inoculation, foliar application of zinc oxide and selenium nanoparticles (ZnO-NPs and Se-NPs), and their combined interactions on the growth and productivity of chili pepper under cold-stress conditions. Two field experiments were successfully conducted during the winter seasons of 2021 and 2022 in an experimental field at the Faculty of Agriculture, Cairo University, Giza, Egypt. The results showed that, under cold stress, the combination of AMF inoculation and ZnO-NPs + Se-NPs as a foliar spray increased the average fruit weight by 92.4% and 98.7%, and the number of fruits by 34.6% and 54.8 compared to control treatment in the 2021 and 2022 seasons, respectively. Additionally, the combination of AMF and a mixture of nanoparticles (ZnO-NPs + Se-NPs) significantly increased the total marketable yield by 95.8% and 94.7% compared to the control, which recorded values of 2.4 and 1.9 kg m−2 in the 2021 and 2022 seasons, respectively. Furthermore, the combination of AMF and a mixture of nanoparticles (ZnO-NPs + Se-NPs) showed the highest total content of ascorbic acid and capsaicin in chili fruits compared to the other treatments. The combination of AMF and a mixture of nanoparticles (ZnO-NPs + Se-NPs) stimulated the accumulation of peroxidase (POD) and nitrogen glutamate dehydrogenase (GDH) while decreasing hydrogen peroxide (H2O2) and lipid peroxidation (MDA) contents. SDS analysis revealed that the application of ZnO-NPs, Se-NPs, AMF + ZnO-NPs, and AMF + ZnO-NPs + Se-NPs induced the emergence of new protein bands and reconstitution of those damaged by cold stress. Regarding histological structure, the combination of AMF inoculation and ZnO-NPs + Se-NPs as a foliar spray showed an enhancement in the thickness of grana thylakoids and increased the number of chloroplasts. Intriguingly, the findings showed that AMF and a mixture of nanoparticles (ZnO-NPs + Se-NPs) could offer guidance for increasing plant development and productivity under cold-stress conditions. [ABSTRACT FROM AUTHOR]

Ketogenic diet (KD) alleviates refractory epilepsy and reduces seizures in children. However, the metabolic/cell biologic mechanisms by which the KD exerts its antiepileptic efficacy remain elusive. Herein, we report that KD-produced β-hydroxybutyric acid (BHB) augments brain gamma-aminobutyric acid (GABA) and the GABA/glutamate ratio to inhibit epilepsy. The KD ameliorated pentetrazol-induced epilepsy in mice. Mechanistically, KD-produced BHB, but not other ketone bodies, inhibited HDAC1/HDAC2, increased H3K27 acetylation, and transcriptionally upregulated SIRT4 and glutamate decarboxylase 1 (GAD1). BHB-induced SIRT4 de-carbamylated and inactivated glutamate dehydrogenase to preserve glutamate for GABA synthesis, and GAD1 upregulation increased mouse brain GABA/glutamate ratio to inhibit neuron excitation. BHB administration in mice inhibited epilepsy induced by pentetrazol. BHB-mediated relief of epilepsy required high GABA level and GABA/glutamate ratio. These results identified BHB as the major antiepileptic metabolite of the KD and suggested that BHB may serve as an alternative and less toxic antiepileptic agent than KD. [ABSTRACT FROM AUTHOR]

Background. Giardia duodenalis causes sporadic or epidemic infections in humans. The parasite comprises assemblages A-H with A and B subdivided further into AI-IV and BI-IV subassemblages. Attempts aimed at linking these genotypes with sources and gastrointestinal manifestations of the infection are largely unexplored in rural communities. Methods. In this cross-sectional study, G. duodenalis infection was genotyped and associated with sources, and gastrointestinal signs and symptoms of the disease among residents of Busia County, a rural setting in western Kenya. Demographic and clinical information were captured using standardized forms. Stool specimens were obtained from the patients and used for genotyping at glutamate dehydrogenase and triose-phosphate isomerase loci using the polymerase chain reaction and restriction fragment length polymorphism. Results. Assemblage B (63.6%) was the most prevalent G. duodenalis infection, while A (20.5%) and mixed A/B (15.9%) were also detected. Among the subassemblages, AI (5.7%), AII (8.0%), AIII (3.4), BIII (30.7%), and BIV (17.0%) were diagnosed including the mixed AII/BIII (15.9%), BIII/BIV (15.9%), AI/AIII (2.3%), and AI/AII (1.1%) infections. Binary logistic regression indicated associations for assemblage A with stomach upset, history of nitroimidazole treatment, and residing in a homestead with cattle and B with age < 18 years, history of eating outdoors, vomiting, steatorrhea, and residing in a homestead with cattle, goats, and poultry (p < 0.05 for all). Among the subassemblages, associations were found for AI with residing in a homestead having cattle and history of nitroimidazole treatment, BIII with residing in a homestead having cattle and poultry, and BIV with steatorrhea (p < 0.05 for all). Altogether, this study illustrates that G. duodenalis assemblage B and subassemblage BIII are the most predominant and are linked to age < 18 years, gastrointestinal manifestations, and living in a homestead with domestic ruminants and poultry. Conclusion. Targeted mass prophylactic treatment of domestic animals and utilization of gastrointestinal presentations, age < 18 years, and a history of nitroimidazole use are useful in the diagnosis and prevention of giardiasis among residents of rural communities. [ABSTRACT FROM AUTHOR]

Background: The exact pathophysiological mechanisms of SGLT‐2 inhibitors in the development, progression or treatment of malignancies are not fully understood, but multiple hypotheses have been proposed. SGLT‐2 inhibitors have potential anti‐proliferative roles due to several underlying pathophysiological mechanisms, such as inhibition of ATP production, activation of AMPK signalling, induction of apoptosis and ferroptosis, inhibition of glutamate dehydrogenase activity and inhibition of DNA and RNA synthesis. However, heterogeneity among tumour cells and SGLT‐2 inhibitor drugs limit the generalizability of pre‐clinical studies. Methods: This is a narrative review discussing the potential anti‐cancer effects of SGLT‐2 inhibitors, an oral glucose‐lowering medication used in patients with type II diabetes mellitus. This review discusses underlying mechanisms, pre‐clinical and clinical trial data, epidemiological data and future perspectives on the use of SGLT‐2 inhibitors in cancer treatment. Results: Type II diabetes is linked to various comorbidities and malignancies, but some glucose‐slowering medications may have a preventive role in cancer. The use of SGLT‐2 inhibitors was associated with bladder cancer based on mice studies. However, meta‐analyses showed no significant increase in overall malignancy incidence of any specific type, except for empagliflozin and bladder cancer association. SGLT‐2 inhibitors can potentially reduce the heart damage caused by doxorubicin and sunitinib, while enhancing the anti‐cancer effects of doxorubicin. Combining SGLT‐2 inhibitors with doxorubicin may allow higher doses of chemotherapy use. Multiple ongoing clinical trials are investigating the potential therapeutic potential of SGLT‐2 inhibitors in various types of cancer. Conclusion: More large‐scale pre‐clinical and clinical studies are needed to explore their potential preventive and therapeutic roles of SGLT‐2 inhibitors in cancer treatment. In this narrative review, our aim is to explore the pre‐clinical and clinical data regarding the potential anti‐cancer effects of SGLT‐2 inhibitors including the hypothetical pathophysiological mechanisms. [ABSTRACT FROM AUTHOR]

Background: Canine atopic dermatitis (CAD) is caused by skin barrier dysfunction due to allergen exposure. Excessive glutamate release in the skin is associated with delayed skin barrier function recovery and epidermal thickening and lichenification. Treatment with Yokukansan (YKS), a traditional Japanese medicine, reduces dermatitis severity and scratching behavior in NC/Nga mice by decreasing epidermal glutamate levels. However, the association between canine keratinocytes and glutamate and the mechanism by which YKS inhibits glutamate release from keratinocytes remains unknown. Aim: We aimed to investigate glutamate release from canine progenitor epidermal keratinocytes (CPEKs) and the inhibitory effect of YKS on this release. We also explored the underlying mechanism of YKS to enable its application in CAD treatment. Methods: Glutamate produced from CPEKs in the medium at 24 hours was measured. The measurement conditions varied in terms of cell density and YKS concentration. CPEKs were treated with a glutamate receptor antagonist (MK-801), a glutamate transporter antagonist (THA), and a glutamate dehydrogenase inhibitor (epigallocatechin gallate; EGCG), and the inhibitory effect of YKS, YKS + THA, MK-801, and EGCG on this release was determined. MK-801 and glutamate dehydrogenase inhibitor were tested alone, and THA was tested in combination with YKS. Finally, glutamine incorporated into CPEKs at 24 hours was measured using radioisotope labeling. Results: CPEKs released glutamate in a cell density-dependent manner, inhibited by YKS in a concentration-dependent manner. Moreover, YKS reduced the intracellular uptake of radioisotope-labeled glutamine in a concentration-dependent manner. No involvement of glutamate receptor antagonism or activation of glutamate transporters was found, as suggested by previous studies. In addition, EGCG could inhibit glutamate release from CPEKs. Conclusion: Our findings indicated that glutamate release from CPEKs could be effectively inhibited by YKS, suggesting the utility of YKS in maintaining skin barrier function during CAD. In addition, CPEKs are appropriate for analyzing the mechanism of YKS. However, we found that the mechanism of action of YKS differs from that reported in previous studies, suggesting that it may have had a similar effect to EGCG in this study. Further research is warranted to understand the exact mechanism and clinical efficacy in treating CAD. [ABSTRACT FROM AUTHOR]

Chinese cabbage is the most widely consumed vegetable crop due to its high nutritional value and rock-bottom price. Notably, the presence of the physiological disease petiole spot significantly impacts the appearance quality and marketability of Chinese cabbage. It is well known that excessive nitrogen fertilizer is a crucial factor in the occurrence of petiole spots; however, the mechanism by which excessive nitrogen triggers the formation of petiole spots is not yet clear. In this study, we found that petiole spots initially gather in the intercellular or extracellular regions, then gradually extend into intracellular regions, and finally affect adjacent cells, accompanied by cell death. Transcriptomic and proteomic as well as physiology analyses revealed that the genes/proteins involved in nitrogen metabolism exhibited different expression patterns in resistant and susceptible Chinese cabbage lines. The resistant Chinese cabbage line has high assimilation ability of NH4+, whereas the susceptible one accumulates excessive NH4+, thus inducing a burst of reactive oxygen species (ROS). These results introduce a novel perspective to the investigation of petiole spot induced by the nitrogen metabolism pathway, offering a theoretical foundation for the development of resistant strains in the control of petiole spot. [ABSTRACT FROM AUTHOR]

Background. The fall armyworm, Spodoptera frugiperda, is an agricultural pest of significant economic concern globally, known for its adaptability, pesticide resistance, and damage to key crops such as maize. Conventional chemical pesticides pose challenges, including the development of resistance and environmental pollution. The study aims to investigate an alternative solution: the application of soluble silicon (Si) sources to enhance plant resistance against the fall armyworm. Methods. Silicon dioxide (SiO2) and potassium silicate (K2SiO3) were applied to maize plants via foliar spray. Transcriptomic and biochemical analyses were performed to study the gene expression changes in the fall armyworm feeding on Si-treated maize. Results. Results indicated a significant impact on gene expression, with a large number of differentially expressed genes (DEGs) identified in both SiO2 and K2SiO3 treatments. Furthermore, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis identified critical DEGs involved in specific pathways, including amino acid, carbohydrate, lipid, energy, xenobiotics metabolisms, signal transduction, and posttranslational modification, significantly altered at both Si sources. Biochemical analyses further revealed that Si treatments inhibited several enzyme activities (glutamate dehydrogenase, trehalase, glucose-6-phosphate dehydro-genase, chitinase, juvenile hormone esterase, and cyclooxygenase while simultaneously inducing others (total protein, lipopolysaccharide, fatty acid synthase, ATPase, and cytochrome P450), thus suggesting a toxic effect on the fall armyworm. In conclusion, Si applications on maize influence the gene expression and biochemical activities of the fall armyworm, potentially offering a sustainable pest management strategy. [ABSTRACT FROM AUTHOR]

Transaminase (TA) is a crucial biocatalyst for enantioselective production of the herbicide L-phosphinothricin (L-PPT). The use of enzymatic cascades has been shown to effectively overcome the unfavorable thermodynamic equilibrium of TA-catalyzed transamination reaction, also increasing demand for TA stability. In this work, a novel thermostable transaminase (PtTA) from Pseudomonas thermotolerans was mined and characterized. The PtTA showed a high specific activity (28.63 U/mg) towards 2‐oxo‐4‐[(hydroxy)(methyl)phosphinoyl]butyric acid (PPO), with excellent thermostability and substrate tolerance. Two cascade systems driven by PtTA were developed for L-PPT biosynthesis, including asymmetric synthesis of L-PPT from PPO and deracemization of D, L-PPT. For the asymmetric synthesis of L-PPT from PPO, a three-enzyme cascade was constructed as a recombinant Escherichia coli (E. coli G), by co-expressing PtTA, glutamate dehydrogenase (GluDH) and D-glucose dehydrogenase (GDH). Complete conversion of 400 mM PPO was achieved using only 40 mM amino donor L-glutamate. Furthermore, by coupling D-amino acid aminotransferase (Ym DAAT) from Bacillus sp. YM‐1 and PtTA, a two-transaminase cascade was developed for the one-pot deracemization of D, L-PPT. Under the highest reported substrate concentration (800 mM D, L-PPT), a 90.43% L-PPT yield was realized. The superior catalytic performance of the PtTA-driven cascade demonstrated that the thermodynamic limitation was overcome, highlighting its application prospect for L-PPT biosynthesis. Key points: • A novel thermostable transaminase was mined for L-phosphinothricin biosynthesis. • The asymmetric synthesis of L-phosphinothricin was achieved via a three-enzyme cascade. • Development of a two-transaminase cascade for D, L-phosphinothricin deracemization. [ABSTRACT FROM AUTHOR]

Background: T cell immunoglobulin and mucin-domain containing-3 (TIM-3) is a cell surface molecule that was first discovered on T cells. However, recent studies revealed that it is also highly expressed in acute myeloid leukemia (AML) cells and it is related to AML progression. As, Glutamine appears to play a prominent role in malignant tumor progression, especially in their myeloid group, therefore, in this study we aimed to evaluate the relation between TIM-3/Galectin-9 axis and glutamine metabolism in two types of AML cell lines, HL-60 and THP-1. Methods: Cell lines were cultured in RPMI 1640 which supplemented with 10% FBS and 1% antibiotics. 24, 48, and 72 h after addition of recombinant Galectin-9 (Gal-9), RT-qPCR analysis, RP-HPLC and gas chromatography techniques were performed to evaluate the expression of glutaminase (GLS), glutamate dehydrogenase (GDH) enzymes, concentration of metabolites; Glutamate (Glu) and alpha-ketoglutarate (α-KG) in glutaminolysis pathway, respectively. Western blotting and MTT assay were used to detect expression of mammalian target of rapamycin complex (mTORC) as signaling factor, GLS protein and cell proliferation rate, respectively. Results: The most mRNA expression of GLS and GDH in HL-60 cells was seen at 72 h after Gal-9 treatment (p = 0.001, p = 0.0001) and in THP-1 cell line was observed at 24 h after Gal-9 addition (p = 0.001, p = 0.0001). The most mTORC and GLS protein expression in HL-60 and THP-1 cells was observed at 72 and 24 h after Gal-9 treatment (p = 0.0001), respectively. MTT assay revealed that Gal-9 could promote cell proliferation rate in both cell lines (p = 0.001). Glu concentration in HL-60 and α-KG concentration in both HL-60 (p = 0.03) and THP-1 (p = 0.0001) cell lines had a decreasing trend. But, Glu concentration had an increasing trend in THP-1 cell line (p = 0.0001). Conclusion: Taken together, this study suggests TIM-3/Gal-9 interaction could promote glutamine metabolism in HL-60 and THP-1 cells and resulting in AML development. [ABSTRACT FROM AUTHOR]

Background: Renal cell carcinoma (RCC) is a common primary tumor of the kidney and is divided into three major subtypes, of which clear cell renal cell carcinoma (ccRCC) has the highest incidence. Glutamate dehydrogenase 1 (GLUD1) encodes glutamate dehydrogenase 1, which catalyzes the oxidative deamination of glutamate. Methods: We analyzed TCGA data using R language software and used multiple online databases to explore the relationship of GLUD1 with signaling pathways and drug sensitivity as well as GLUD1 protein expression and methylation. Results: The results showed that GLUD1 mRNA expression was reduced in tumor tissues and correlated with the progression of ccRCC. Univariate and multivariate Cox analysis showed that GLUD1 could be used as a prognostic marker for ccRCC. GLUD1 expression in ccRCC was associated with immune cells infiltration and multiple classical signaling pathways. In addition, GLUD1 mRNA expression was related to drug sensitivity. Conclusions: These findings provide new ideas for finding new prognostic molecular markers and therapeutic targets for ccRCC. [ABSTRACT FROM AUTHOR]

Glutamate dehydrogenase 1 (GLUD1) is an important enzyme in glutamine metabolism. Previously, we found GLUD1 was down-regulated in tumor tissues of hepatocellular carcinoma (HCC) patients by proteomics study. To explore its role in the progression of HCC, the expressional level of GLUD1 was firstly examined and presented as that both the protein and mRNA levels were down-regulated in tumor tissues compared to the normal liver tissues. GLUD1 overexpression significantly inhibited HCC cells proliferation, migration, invasion and tumor growth both in vitro and in vivo, while GLUD1 knocking-down promoted HCC progression. Metabolomics study of GLUD1 overexpressing and control HCC cells showed that 129 differentially expressed metabolites were identified, which mainly included amino acids, bases, and phospholipids. Moreover, metabolites in mitochondrial oxidative phosphorylation system (OXPHOS) were differentially expressed in GLUD1 overexpressing cells. Mechanistic studies showed that GLUD1 overexpression enhanced mitochondrial respiration activity and reactive oxygen species (ROS) production. Excessive ROS lead to mitochondrial apoptosis that was characterized by increased expression levels of p53, Cytochrome C, Bax, Caspase 3 and decreased expression level of Bcl-2. Furthermore, we found that the p38/JNK MAPK pathway was activated in GLUD1 overexpressing cells. N-acetylcysteine (NAC) treatment eliminated cellular ROS and blocked p38/JNK MAPK pathway activation, as well as cell apoptosis induced by GLUD1 overexpression. Taken together, our findings suggest that GLUD1 inhibits HCC progression through regulating cellular metabolism and oxidative stress state, and provide that ROS generation and p38/JNK MAPK pathway activation as promising methods for HCC treatment. [ABSTRACT FROM AUTHOR]

Shewanella oneidensis is a gram-negative bacterium known for its unique respiratory capabilities, which allow it to utilize a wide range of electron acceptors, including solid substrates such as electrodes. For a future combination of chemical production and electro-fermentation, the goal of this study was to expand its product spectrum. S. oneidensis was metabolically engineered to optimize its glutamate production and to enable production of itaconic acid. By deleting the glutamate importer gltS for a reduced glutamate uptake and pckA/ptA to redirect the carbon flux towards the TCA cycle, a ∆3 mutant was created. In combination with the plasmid pG2 carrying the glutamate dehydrogenase gdhA and a specific glutamate exporter NCgl1221 A111V, a 72-fold increase in glutamate concentration compared to the wild type was achieved. Along with overexpression of gdhA and NCgl1221 A111V, the deletion of gltS and pckA/ptA as well as the deletion of all three genes (∆3) was examined for their impact on growth and lactate consumption. This showed that the redirection of the carbon flux towards the TCA cycle is possible. Furthermore, we were able to produce itaconic acid for the first time with a S. oneidensis strain. A titer of 7 mM was achieved after 48 h. This suggests that genetic optimization with an expression vector carrying a cis-aconitate decarboxylase (cadA) and a aconitate hydratase (acnB) along with the proven redirection of the carbon flux to the TCA cycle enabled the production of itaconic acid, a valuable platform chemical used in the production of a variety of products. Key points: •Heterologous expression of gdhA and NCgl1221_A111V leads to higher glutamate production. •Deletion of ackA/pta redirects carbon flux towards TCA cycle. •Heterologous expression of cadA and acnB enables itaconic acid production. [ABSTRACT FROM AUTHOR]

Glutamate dehydrogenase (GDH) interconverts glutamate to a-ketoglutarate and ammonia, interconnecting amino acid and carbohydrate metabolism. In humans, two functional GDH genes, GLUD1 and GLUD2, encode for hGDH1 and hGDH2, respectively. GLUD2 evolved from retrotransposition of the GLUD1 gene in the common ancestor of modern apes. These two isoenzymes are involved in the pathophysiology of human metabolic, neoplastic, and neurodegenerative disorders. The 3D structures of hGDH1 and hGDH2 have been experimentally determined; however, no information is available about the path of GDH2 structure changes during primate evolution. Here, we compare the structures predicted by the AlphaFold Colab method for the GDH2 enzyme of modern apes and their extinct primate ancestors. Also, we analyze the individual effect of amino acid substitutions emerging during primate evolution. Our most important finding is that the predicted structure of GDH2 in the common ancestor of apes was the steppingstone for the structural evolution of primate GDH2s. Two changes with a strong functional impact occurring at the first evolutionary step, Arg443Ser and Gly456Ala, had a destabilizing and stabilizing effect, respectively, making this step the most important one. Subsequently, GDH2 underwent additional modifications that fine-tuned its enzymatic properties to adapt to the functional needs of modern-day primate tissues. [ABSTRACT FROM AUTHOR]

Liver function has been suggested as a possible factor in the progression of Alzheimer's disease (AD) development. However, the association between liver function and cerebrospinal fluid (CSF) levels of AD biomarkers remains unclear. In this study, we analyzed the data from 1687 adults without dementia from the Chinese Alzheimer's Biomarker and LifestylE study to investigate differences in liver function between pathological and clinical AD groups, as defined by the 2018 National Institute on Aging‐Alzheimer's Association Research Framework. We also examined the linear relationship between liver function, CSF AD biomarkers, and cognition using linear regression models. Furthermore, mediation analyses were applied to explore the potential mediation effects of AD pathological biomarkers on cognition. Our findings indicated that, with AD pathological and clinical progression, the concentrations of total protein (TP), globulin (GLO), and aspartate aminotransferase/alanine transaminase (ALT) increased, while albumin/globulin (A/G), adenosine deaminase, alpha‐L‐fucosidase, albumin, prealbumin, ALT, and glutamate dehydrogenase (GLDH) concentrations decreased. Furthermore, we also identified significant relationships between TP (β = −0.115, pFDR < 0.001), GLO (β = −0.184, pFDR < 0.001), and A/G (β = 0.182, pFDR < 0.001) and CSF β‐amyloid1–42 (Aβ1–42) (and its related CSF AD biomarkers). Moreover, after 10 000 bootstrapped iterations, we identified a potential mechanism by which TP and GLDH may affect cognition by mediating CSF AD biomarkers, with mediation effect sizes ranging from 3.91% to 16.44%. Overall, our results suggested that abnormal liver function might be involved in the clinical and pathological progression of AD. Amyloid and tau pathologies also might partially mediate the relationship between liver function and cognition. Future research is needed to fully understand the underlying mechanisms and causality to develop an approach to AD prevention and treatment approach. [ABSTRACT FROM AUTHOR]

Background: This study was performed to determine the magnitude of Clostridioides difficile infection (CDI) in a tertiary care hospital in patients with antibiotic associated diarrhea (AAD) and to study the risk factors associated with this disease. Methods: A descriptive study was conducted in the department of Microbiology in a tertiary care hospital during December 2019 to May 2021. Stool samples were collected from patients with signs and symptoms of AAD who had been consuming antibiotic or anticancer drugs durng six weeks before the sampling. The samples were subjected to C. difficile glutamate dehydrogenase (GDH) enzyme and CD toxin A & B detection by Enzyme Linked Fluorescent Assay (ELFA). Patient’s demographic features and clinical details were noted and statistically correlated with the test results. Results: Among the total 70 samples tested 20 (28%) were positive for GDH alone and 12 (17%) were positive for both GDH and CD toxin A and B. Fluoroquinolones was a significant risk factor in the study. Sepsis and colitis was found to have significant association with C.difficile infection in our study. The crude mortality rate was 17%. Conclusion: Prompt and precise diagnosis and knowledge about the risk factors of CDI helps in effective management and prevention of CDI. [ABSTRACT FROM AUTHOR]

Changes in protein abundance and reversible protein phosphorylation (RPP) play important roles in regulating hypometabolism but have never been documented in overwintering frogs at high altitudes. To test the hypothesis that protein abundance and phosphorylation change in response to winter hibernation, we conducted a comprehensive and quantitative proteomic and phosphoproteomic analysis of the liver of the Xizang plateau frog, Nanorana parkeri, living on the Qinghai- Xizang Plateau. In total, 5 170 proteins and 5 695 phosphorylation sites in 1 938 proteins were quantified. Based on proteomic analysis, 674 differentially expressed proteins (438 up-regulated, 236 down-regulated) were screened in hibernating N. parkeri versus summer individuals. Functional enrichment analysis revealed that higher expressed proteins in winter were significantly enriched in immune-related signaling pathways, whereas lower expressed proteins were mainly involved in metabolic processes. A total of 4 251 modified sites (4 147 up-regulated, 104 down-regulated) belonging to 1 638 phosphoproteins (1 555 up-regulated, 83 down-regulated) were significantly changed in the liver. During hibernation, RPP regulated a diverse array of proteins involved in multiple functions, including metabolic enzymatic activity, ion transport, protein turnover, signal transduction, and alternative splicing. These changes contribute to enhancing protection, suppressing energy-consuming processes, and inducing metabolic depression. Moreover, the activities of phosphofructokinase, glutamate dehydrogenase, and ATPase were all significantly lower in winter compared to summer. In conclusion, our results support the hypothesis and demonstrate the importance of RPP as a regulatory mechanism when animals transition into a hypometabolic state. [ABSTRACT FROM AUTHOR]

Background: Healthcare-associated diarrhea (HCAD) is diarrhea that develops at least after 3 days of hospitalization, with the most common infectious cause being Clostridioides difficile. Over the last decade, there has been a remarkable growth in the frequency and severity of C. difficile infection (CDI), making it one of the most prevalent healthcare-associated infections. This study aimed to analyze the prevalence and risk factors associated with CDI. Materials and methods: A total of 107 patients with clinical suspicion of having HCAD were included in this study. Enzyme-linked fluorescent assay (ELFA) technique-based glutamate dehydrogenase (GDH) and toxin A/B assay were used as per the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) for diagnosing CDI. The details about associated comorbidities were retrieved from the hospital information system records. The presence of risk factors was noted. Risk factors associated with CDI were looked for. Results: Out of the 107 stool samples received in the microbiology laboratory from patients with suspected HCAD eight (7.6%) samples were positive for CDI. The most frequent comorbidity observed in these patients was renal illness (acute or chronic kidney disease). In this study, a total of 7/8 cases were on multiple antibiotics most common being carbapenem. Conclusion: The 6-year prevalence of CDI observed in this study was found to be 7.6% risk factors, associated with CDI were kidney disease, diabetes mellitus, malignancy, and exposure to broad-spectrum antibiotics. [ABSTRACT FROM AUTHOR]

Multi-enzyme assemblies composed of metabolic enzymes catalyzing sequential reactions are being increasingly studied. Here, we report the discovery of a 1.6 megadalton multi-enzyme complex from Bacillus subtilis composed of two enzymes catalyzing opposite ('counter-enzymes') rather than sequential reactions: glutamate synthase (GltAB) and glutamate dehydrogenase (GudB), which make and break glutamate, respectively. In vivo and in vitro studies show that the primary role of complex formation is to inhibit the activity of GudB. Using cryo-electron microscopy, we elucidated the structure of the complex and the molecular basis of inhibition of GudB by GltAB. The complex exhibits unusual oscillatory progress curves and is necessary for both planktonic growth, in glutamate-limiting conditions, and for biofilm growth, in glutamate-rich media. The regulation of a key metabolic enzyme by complexing with its counter enzyme may thus enable cell growth under fluctuating glutamate concentrations.

The effect of salt stress (150 mM NaCl) on the expression of genes, methylation of their promoters, and enzymatic activity of glutamate dehydrogenase (GDH), glutamate decarboxylase (GAD), and the 2-oxoglutarate (2-OG)–dehydrogenase (2-OGDH) complex was studied in maize (Zea mays L.). GDH activity increased continuously under salt stress, being 3-fold higher after 24 h. This was accompanied by the appearance of a second isoform with lower electrophoretic mobility. The expression of the Gdh1 gene strongly increased after 6–12 h of incubation, which corresponded to the demethylation of its promoter, while Gdh2 gene expression slightly increased after 2–6 h and then decreased. GAD activity gradually increased in the first 12 h, and then returned to the control level. This corresponded to the increase of Gad expression and its demethylation. Salt stress led to a 2-fold increase in the activity of 2-OGDH during the first 6 h of NaCl treatment, then the activity returned to the control level. Expression of the genes Ogdh1 and Ogdh3 peaked after 1–2 h of incubation. After 6–8 h with NaCl, the expression of these genes declined below the control levels, which correlated with the higher methylation of their promoters. We conclude that salt stress causes a redirection of the 2-OG flux to the γ-aminobutyric acid shunt via its amination to glutamate, by altering the expression of the Gdh1 and Gdh2 genes, which likely promotes the assembly of the native GDH molecule having a different subunit composition and greater affinity for 2-OG.

Background: This study was performed to determine the magnitude of Clostridioides difficile infection (CDI) in a tertiary care hospital in patients with antibiotic associated diarrhea (AAD) and to study the risk factors associated with this disease. Methods: A descriptive study was conducted in the department of Microbiology in a tertiary care hospital during December 2019 to May 2021. Stool samples were collected from patients with signs and symptoms of AAD who had been consuming antibiotic or anticancer drugs durng six weeks before the sampling. The samples were subjected to C. difficile glutamate dehydrogenase (GDH) enzyme and CD toxin A & B detection by Enzyme Linked Fluorescent Assay (ELFA). Patient’s demographic features and clinical details were noted and statistically correlated with the test results. Results: Among the total 70 samples tested 20 (28%) were positive for GDH alone and 12 (17%) were positive for both GDH and CD toxin A and B. Fluoroquinolones was a significant risk factor in the study. Sepsis and colitis was found to have significant association with C.difficile infection in our study. The crude mortality rate was 17%. Conclusion: Prompt and precise diagnosis and knowledge about the risk factors of CDI helps in effective management and prevention of CDI.

In this work, it was shown for the first time that inactivation of the L-lysine uptake transport system from the external environment leads to an increase in the level of L-threonine synthesis by the Escherichia coli strain that produces it, while the addition of lysine to the culture medium reduces the productivity of the unmodified strain, which indicates the influence of the intracellular pool of lysine on the efficiency of threonine biosynthesis. A study of the possible mechanisms of this influence showed that neither the previously known inhibition of aspartate kinase III (LysC) activity, nor the repression of the synthesis of aspartate semialdehyde dehydrogenase (Asd) and glutamate dehydrogenase (GdhA) individually are reasons for the decrease in culture productivity. The results we obtained may indicate both the presence of a previously unknown mechanism for the regulation of threonine metabolism by lysine and the fact that several enzymes in the threonine biosynthesis pathway are simultaneously affected by this amino acid. At the same time, changing the permeability of the membrane to lysine, or reducing its intracellular concentration as a result of changing the efficiency of its biosynthesis, is a promising approach for improving threonine-producing strains. [ABSTRACT FROM AUTHOR]

Simple Summary: Giardia duodenalis is a common zoonotic intestinal protozoan and causes significant economic losses and potential risks to public health. China is among the several major producers of donkeys worldwide, with approximately 2.6 million donkeys being reared in 2019, but studies on G. duodenalis infection in donkeys were limited. Thus, in order to better understand the molecular epidemiology of G. duodenalis in donkeys in China, 815 fecal samples were collected from donkeys in three representative geographical locations in Shanxi Province, North China, to determine the presence and genotypes of G. duodenalis based on three established loci (tpi, bg, and gdh). A total of 137 out of 815 fecal samples were detected as G. duodenalis-positive with an overall prevalence of 16.81%. Among the detected assemblages A, B, and E, the most predominant assemblage was B in the three study areas. Three MLGs (MLG-novel-1 to 3) were identified with multilocus genotypes (MLGs) analysis and validated by a phylogenetic tree. This is the first report of G. duodenalis infection in donkeys in Shanxi Province, which not only enhances our understanding of the genetic diversity of G. duodenalis in donkeys in China but also provides essential baseline data for the prevention and control of G. duodenalis infection donkeys in the study areas. Giardia duodenalis is a ubiquitous flagellated protozoan, causing significant economic losses to animal husbandry and posing threats to public health. China ranks the world's sixth largest major producer of donkeys, rearing approximately 2.6 million donkeys in 2019, but limited investigation of G. duodenalis prevalence has been conducted in the past, and it is yet to be known whether donkeys in Shanxi Province are infected with G. duodenalis. In the present study, a total of 815 fecal samples collected from donkeys in representative regions of Shanxi Province, North China, were examined for G. duodenalis using nested PCR. Then, the assemblages and multilocus genotypes (MLGs) were examined based on three established loci: namely, β-giardin (bg), triosephosphate isomerase (tpi), and glutamate dehydrogenase (gdh). The overall prevalence of G. duodenalis in donkeys in Shanxi Province was 16.81% (137/815). The region was identified as the main risk factor for the observed difference in G. duodenalis prevalence in donkeys among the three study areas (χ2 = 21.611, p < 0.001). Assemblages A, E, and B were identified, with the latter as the predominant assemblage. Three MLGs (MLG-novel-1 to 3) were formed based on sequence variation among the three loci. The present study reveals the presence of G. duodenalis in donkeys in Shanxi Province, North China, for the first time, which not only enriches the data on the distribution of G. duodenalis in donkeys in China but also provides useful baseline data for planning control strategies against G. duodenalis infection in the sampled areas. [ABSTRACT FROM AUTHOR]

Background: Active hydrothermal vents create extreme conditions characterized by high temperatures, low pH levels, and elevated concentrations of heavy metals and other trace elements. These conditions support unique ecosystems where chemolithoautotrophs serve as primary producers. The steep temperature and pH gradients from the vent mouth to its periphery provide a wide range of microhabitats for these specialized microorganisms. However, their metabolic functions, adaptations in response to these gradients, and coping mechanisms under extreme conditions remain areas of limited knowledge. In this study, we conducted temperature gradient incubations of hydrothermal fluids from moderate (pH = 5.6) and extremely (pH = 2.2) acidic vents. Combining the DNA-stable isotope probing technique and subsequent metagenomics, we identified active chemolithoautotrophs under different temperature and pH conditions and analyzed their specific metabolic mechanisms. Results: We found that the carbon fixation activities of Nautiliales in vent fluids were significantly increased from 45 to 65 °C under moderately acidic condition, while their heat tolerance was reduced under extremely acidic conditions. In contrast, Campylobacterales actively fixed carbon under both moderately and extremely acidic conditions under 30 − 45 °C. Compared to Campylobacterales, Nautiliales were found to lack the Sox sulfur oxidation system and instead use NAD(H)-linked glutamate dehydrogenase to boost the reverse tricarboxylic acid (rTCA) cycle. Additionally, they exhibit a high genetic potential for high activity of cytochrome bd ubiquinol oxidase in oxygen respiration and hydrogen oxidation at high temperatures. In terms of high-temperature adaption, the rgy gene plays a critical role in Nautiliales by maintaining DNA stability at high temperature. Genes encoding proteins involved in proton export, including the membrane arm subunits of proton-pumping NADH: ubiquinone oxidoreductase, K+ accumulation, selective transport of charged molecules, permease regulation, and formation of the permeability barrier of bacterial outer membranes, play essential roles in enabling Campylobacterales to adapt to extremely acidic conditions. Conclusions: Our study provides in-depth insights into how high temperature and low pH impact the metabolic processes of energy and main elements in chemolithoautotrophs living in hydrothermal ecosystems, as well as the mechanisms they use to adapt to the extreme hydrothermal conditions. 4ap83QbxwyKb6GHBwDJLyu Video Abstract [ABSTRACT FROM AUTHOR]

This study aimed to quantify the effects of dietary inclusion of tannin-rich pomegranate peel (PP) on intake, methane and nitrogen (N) losses, and metabolic and health indicators in dairy cows. Four multiparous, late-lactating Brown Swiss dairy cows (796 kg body weight; 29 kg/d of energy corrected milk yield) were randomly allocated to 3 treatments in a randomized cyclic change-over design with 3 periods, each comprising 14 d of adaptation, 7 d of milk, urine, and feces collection, and 2 d of methane measurements. Treatments were formulated using PP that replaced on a dry matter (DM) basis 0% (control), 5%, and 10% of the basal mixed ration (BMR) consisting of corn and grass silage, alfalfa, and concentrate. Gaseous exchange of the cows was determined in open-circuit respiration chambers. Blood samples were collected on d 15 of each period. Individual feed intake as well as feces and urine excretion were quantified, and representative samples were collected for analyses of nutrients and phenol composition. Milk was analyzed for concentrations of fat, protein, lactose, milk urea N, and fatty acids. Total phenols and antioxidant capacity in milk and plasma were determined. In serum, the concentrations of urea and bilirubin as well as the activities of alanine aminotransferase (ALT), aspartate aminotransferase, glutamate dehydrogenase, alkaline phosphatase, and γ-glutamyl transferase were measured. The data were subjected to ANOVA with the Mixed procedure of SAS, with treatment and period as fixed and animal as random effects. The PP and BMR contained 218 and 3.5 g of total extractable tannins per kg DM, respectively, and thereof 203 and 3.3 g of hydrolyzable tannins. Total DM intake, energy corrected milk, and methane emission (total, yield, and intensity) were not affected by PP supplementation. The proportions of C18:2n-6 and C18:3n-3 in milk increased linearly as the amount of PP was increased in the diet. Milk urea N, blood urea N, and urinary N excretion decreased linearly with the increase in dietary PP content. Total phenols and antioxidant capacity in milk and plasma were not affected by the inclusion of PP. The activity of ALT increased in a linear manner with the inclusion of PP. In conclusion, replacing up to 10% of BMR with PP improved milk fatty acid composition and alleviated metabolic and environmental N load. However, the elevated serum ALT activity indicates an onset of liver stress even at 5% PP, requiring the development of adaptation protocols for safe inclusion of PP in ruminant diets. [ABSTRACT FROM AUTHOR]

The structure of hexameric glutamate dehydrogenase (GDH) in the presence of the coenzyme nicotinamide adenine dinucleotide phosphate (NADP) was visualized using cryogenic transmission electron microscopy to investigate the ligand‐binding pathways to the active site of the enzyme. Each subunit of GDH comprises one hexamer‐forming core domain and one nucleotide‐binding domain (NAD domain), which spontaneously opens and closes the active‐site cleft situated between the two domains. In the presence of NADP, the potential map of GDH hexamer, assuming D3 symmetry, was determined at a resolution of 2.4 Å, but the NAD domain was blurred due to the conformational variety. After focused classification with respect to the NAD domain, the potential maps interpreted as NADP molecules appeared at five different sites in the active‐site cleft. The subunits associated with NADP molecules were close to one of the four metastable conformations in the unliganded state. Three of the five binding sites suggested a pathway of NADP molecules to approach the active‐site cleft for initiating the enzymatic reaction. The other two binding modes may rarely appear in the presence of glutamate, as demonstrated by the reaction kinetics. Based on the visualized structures and the results from the enzymatic kinetics, we discussed the binding modes of NADP to GDH in the absence and presence of glutamate. [ABSTRACT FROM AUTHOR]

Nickel (Ni) contamination hinders plant growth and yield. Nitric oxide (NO) and thiourea (Thi) aid plant recovery from heavy metal damage, but their combined effects on pepper (Capsicum annuum) plant tolerance to Ni stress need more study. Sodium nitroprusside (0.1 mM, SNP) and 400 mg L−1 Thi, alone and combined, were studied for their impact on pepper growth under Ni toxicity. Ni stress reduces chlorophyll, PSII efficiency and leaf water and sugar content. However, SNP and Thi alleviate these effects by increasing leaf water, proline and sugar content. It also increased the activities of superoxide dismutase, catalase, ascorbate peroxidase and peroxidase. Nickel stress lowered nitrogen assimilation enzymes (nitrate reductase, nitrite reductase, glutamine synthetase, glutamate synthase and glutamate dehydrogenase) and protein content, but increased nitrate, ammonium and amino acid content. SNP and Thi enhanced nitrogen assimilation, increased protein content and improved pepper plant growth and physiological functions during Ni stress. The combined treatment reduced Ni accumulation, increased Ni in leaf cell walls and potentially in root vacuoles, and decreased Ni concentration in cell organelles. It effectively mitigated Ni toxicity to vital organelles, surpassing the effects of SNP or Thi use alone. This study provides valuable insights for addressing heavy metal contamination in agricultural soils and offers potential strategies for sustainable and eco-friendly farming practices. Nickel contamination hinders plant growth and yield. Nitric oxide (NO) and thiourea aid plant recovery from heavy metal damage, but their combined effects on pepper (Capsicum annuum) tolerance to Ni stress need more study. Combined use of NO and thiourea alleviates Ni stress effects on pepper by enhancing leaf water, proline, sugar content, antioxidant enzyme activities and Ni distribution. These findings contribute valuable insights for addressing heavy metal contamination in agricultural soils and promoting sustainable and eco-friendly farming practices. [ABSTRACT FROM AUTHOR]

Enhancing crop residue digestibility can boost the available energy for growth and milk yield and improve the sustainability of ruminant production systems. As the natural diet of bison is high in lignocellulose, bison have developed a microbiome that efficiently digests cellulose and hemicellulose. This study compared the rumen metatranscriptomes of bison and beef heifers and investigated the effects of inoculating heifers with bison rumen contents. Gene Ontology, molecular function, and Kyoto Encyclopedia of Genes and Genomes orthology terms identified through gene set enrichment analysis successfully captured differences in gene expression of rumen microbiome between heifers and bison fed different diets. Specifically, differences in nitrogen metabolism was detected between heifers and bison rumen microbiomes. Heifer rumen microbiomes demonstrated a higher dissimilatory nitrate reduction, while bison microbiomes tended to suppress this pathway. In contrast, bison microbiomes expressed higher levels of glutamate dehydrogenase 2 (GDH2) genes. However, glutamate dehydrogenase gene expression was observed to be strictly regulated in heifers, as inoculation with bison rumen contents had no effect on expression. Moreover, the transfer of bison rumen contents led to a persistent downregulation of microbial nitrogen metabolism in heifers after 27 days of transfer. In addition, gene set enrichment analysis also identified the crucial regulatory role of serine/threonine kinase in heifer rumen microbial metabolism and differences in ion transport between heifers and bison. These findings provide valuable insights into the complex interplay between diet and the rumen microbiome. IMPORTANCE Ruminants play a key role in the conversion of cellulolytic plant material into high-quality meat and milk protein for humans. The rumen microbiome is the driver of this conversion, yet there is little information on how gene expression within the microbiome impacts the efficiency of this conversion process. The current study investigates gene expression in the rumen microbiome of beef heifers and bison and how transplantation of ruminal contents from bison to heifers alters gene expression. Understanding interactions between the host and the rumen microbiome is the key to developing informed approaches to rumen programming that will enhance production efficiency in ruminants. [ABSTRACT FROM AUTHOR]

Diabetes mellitus is a prevalent metabolic disorder characterized by impaired insulin secretion and aberrant lipid metabolism. Targeting glutamate dehydrogenase (GDH) activators has emerged as a potential therapeutic strategy in managing diabetes. This study aims to investigate the effects of GDH activators on insulin secretion and lipid profiles in diabetic rabbits. Utilizing Streptozotocin (STZ) to induce diabetes in male New Zealand White rabbits, the impacts of three different GDH activators--Metformin, Epigallocatechin Gallate (EGCG), and Leucine--were examined. The subjects were categorized into five groups, including a diabetic control, a sham group, and three treatment groups administered with Metformin (5 mg kg-1), EGCG (15 mg kg-1), and Leucine (15 mg kg-1), respectively. The study reveals significant modulations in insulin and lipid profiles due to these treatments. In the Metformin-treated group, blood glucose levels significantly decreased during the second (p < 0.001) and third (p<0.01) weeks. The EGCG group exhibited a significant increase in insulin levels (p < 0.001), but no notable change in blood glucose. Conversely, the Leucine group showed an increase in triglyceride levels (p < 0.05) and a significant decrease in blood glucose levels (p < 0.01). Additionally, Metformin led to a substantial reduction in triglycerides (p < 0.001), while EGCG and Leucine were effective in lowering LDL levels (p < 0.01). Cholesterol and HDL levels remained relatively unchanged across all groups. These findings suggest that GDH activators, i.e., Metformin, EGCG, and Leucine, significantly impact insulin secretion and lipid metabolism, offering novel insights into diabetes management. This study not only demonstrates the therapeutic potential of these agents, but also emphasizes the importance of GDH pathways in diabetes research, providing a foundation for future investigations into metabolic regulation and treatment. [ABSTRACT FROM AUTHOR]

Glutamate, a non-essential amino acid produced by fermentation, plays a significant role in disease diagnosis and food safety. It is important to enable the real-time monitoring of glutamate concentration for human health and nutrition. Due to the challenges in directly performing electrochemical oxidation–reduction reactions of glutamate, this study leverages the synergistic effect of glutamate dehydrogenase (GLDH) and nanoporous gold (NPG) to achieve the indirect and accurate detection of glutamate within the range of 50 to 700 μM by measuring the generated quantity of NADH during the enzymatic reaction. The proposed biosensor demonstrates remarkable performance characteristics, including a detection sensitivity of 1.95 μA mM−1 and a limit of detection (LOD) of 6.82 μM. The anti-interference tests indicate an average recognition error ranging from −3.85% to +2.60%, spiked sample recovery rates between 95% and 105%, and a relative standard deviation (RSD) of less than 4.97% for three replicate experiments. Therefore, the GLDH-NPG/GCE biosensor presented in this work exhibits excellent accuracy and repeatability, providing a novel alternative for rapid glutamate detection. This research contributes significantly to enhancing the precise monitoring of glutamate concentration, thereby offering more effective guidance and control for human health and nutrition. [ABSTRACT FROM AUTHOR]

Simple Summary: Blood reference intervals are important for the correct interpretation of blood results but are missing for many wild species. The aim of the present study was therefore to establish specific reference intervals for a series of clinical chemistry and haematology analytes for captive Humboldt penguins (Spheniscus humboldti). The results indicate that the factors of sex and age should be considered when interpreting the results of haematological and clinical biochemistry assays. Reference intervals for clinical chemistry and haematology analytes are essential for the interpretation of blood results, but limited data are available for Humboldt penguins (Spheniscus humboldti) in zoological collections as well as in the wild. The aim of the present study was therefore to establish reference intervals for a series of clinical chemistry and haematology analytes in a single zoological population of Humboldt penguins. Furthermore, possible variations of the analytes influenced by the age and sex of the individuals were investigated. Lithium heparinized plasma and whole blood samples from 39 animals were analysed and statistically evaluated. The following clinical chemistry analytes were significantly higher in females: glutamate dehydrogenase (p = 0.0003), alanine transaminase (p = 0.0005), alkaline phosphatase (p = 0.0245), aspartate aminotransferase (p = 0.0043), creatine kinase (p = 0.0016), lactate dehydrogenase (p < 0.0001), inorganic phosphorus (p = 0.0223), and sodium (p = 0.0415). No significant differences between males and females were found for any haematology analyte. Cholesterol (p = 0.0233; −0.39), white blood cell count (p = 0.0208; −0.40), and absolute heterophiles (p = 0.0148; −0.42) had significant negative correlations with the age of the penguins. The results indicate that the factors of sex and age should be considered when interpreting the results of haematological and clinical biochemistry assays, and further studies are needed to determine whether there are more differences in other age groups or seasons. [ABSTRACT FROM AUTHOR]

Ammonium toxicity in macrophytes reduces growth and development due to a disrupted metabolism and high carbon requirements for internal ammonium detoxification. To provide more molecular support for ammonium detoxification in the above-ground and below-ground parts of Myriophyllum spicatum, we separated (using hermetic bags) the aqueous medium surrounding the below-ground from that surrounding the above-ground and explored the genes in these two regions. The results showed an upregulation of asparagine synthetase genes under high ammonium concentrations. Furthermore, the transcriptional down and/or upregulation of other genes involved in nitrogen metabolism, including glutamate dehydrogenase, ammonium transporter, and aspartate aminotransferase in above-ground and below-ground parts were crucial for ammonium homeostasis under high ammonium concentrations. The results suggest that, apart from the primary pathway and alternative pathway, the asparagine metabolic pathway plays a crucial role in ammonium detoxification in macrophytes. Therefore, the complex genetic regulatory network in M. spicatum contributes to its ammonium tolerance, and the above-ground part is the most important in ammonium detoxification. Nevertheless, there is a need to incorporate an open-field experimental setup for a conclusive picture of nitrogen dynamics, toxicity, and the molecular response of M. spicatum in the natural environment. [ABSTRACT FROM AUTHOR]

In plants, glutamate dehydrogenase (GDH) is an ubiquitous enzyme that catalyzes the reversible amination of 2‐oxoglutarate in glutamate. It contributes to both the amino acid homeostasis and the management of intracellular ammonium, and it is regarded as a key player at the junction of carbon and nitrogen assimilation pathways. To date, information about the GDH of terrestrial plants refers to a very few species only. We focused on selected species belonging to the division Marchantiophyta, providing the first panoramic overview of biochemical and functional features of GDH in liverworts. Native electrophoretic analyses showed an isoenzymatic profile less complex than what was reported for Arabidposis thaliana and other angiosperms: the presence of a single isoform corresponding to an α‐homohexamer, differently prone to thermal inactivation on a species‐ and organ‐basis, was found. Sequence analysis conducted on amino acid sequences confirmed a high similarity of GDH in modern liverworts with the GDH2 protein of A. thaliana, strengthening the hypothesis that the duplication event that gave origin to GDH1‐homolog gene from GDH2 occurred after the evolutionary bifurcation that separated bryophytes and tracheophytes. Experiments conducted on Marchantia polymorpha and Calypogeia fissa grown in vitro and compared to A. thaliana demonstrated through in gel activity detection and monodimensional Western Blot that the aminating activity of GDH resulted in strongly enhanced responses to ammonium excess in liverworts as well, even if at a different extent compared to Arabidopsis and other vascular species. The comparative analysis by bi‐dimensional Western Blot suggested that the regulation of the enzyme could be, at least partially, untied from the protein post‐translational pattern. Finally, immuno‐electron microscopy revealed that the GDH enzyme localizes at the subcellular level in both mitochondria and chloroplasts of parenchyma and is specifically associated to the endomembrane system in liverworts. [ABSTRACT FROM AUTHOR]

Simple Summary: Cryptosporidium spp. and Giardia duodenalis, enteric protozoan pathogens affecting humans and animals, elicit substantial global public concern. This study conducted in Taiwan sought to determine the prevalence and co-infection rates of Cryptosporidium spp. and G. duodenalis in dogs and cats. The investigation encompassed an analysis of infection rates and associated risk factors within the surveyed population. Predominantly identified species were C. canis and C. felis, aligning with canine-specific assemblages C and D. In contrast, the infrequent presence of human-specific assemblage A was noted in Giardia-positive samples. Phylogenetic analysis alluded to the potential for zoonotic transmission originating from domesticated animals. This underscores the role of pets as possible reservoirs for the transmission of cryptosporidiosis and giardiasis to humans in Taiwan. Cryptosporidium spp. and Giardia duodenalis are enteric protozoan pathogens in humans. and animals. Companion animals infected with zoonotic species/assemblages are a matter of major public concern around the world. The objectives of the present study were to determine the prevalences of Cryptosporidium spp. and G. duodenalis infections and their co-infection statuses in dogs and cats living in Taiwan and to identify the species and assemblages. Fecal samples were collected from local animal shelters (n = 285) and a veterinary hospital (n = 108). Nested polymerase chain reaction (PCR) was performed using the SSU-rRNA, β-giardin, and glutamate dehydrogenase genes for Cryptosporidium spp. and G. duodenalis, respectively. Results showed that the overall prevalences of Cryptosporidium and G. duodenalis were 7.38% (29/393) and 10.69% (42/393). In addition, co-infection was detected in 1.02% (4/393) of all samples. Sample source, clinical sign, and breed may be risk factors that influence the infection rate. In Cryptosporidium-positive samples, C. canis and C. felis were detected most frequently. Although the canine-specific assemblages C and D (37/42) were dominant, the zoonotic human-specific assemblage A (1/42) was also found in Giardia-positive samples. Phylogenetic analysis revealed that most positive samples belonged to host-specific subtypes/assemblages, while some Cryptosporidium or Giardia-positive samples could be zoonotic. The findings suggested that pet animals could be a cause of zoonotic transmission, causing human cryptosporidiosis and giardiasis in Taiwan. [ABSTRACT FROM AUTHOR]

Altered hepatic mitochondrial fatty acid β-oxidation and associated tricarboxylic acid (TCA) cycle activity contributes to lifestyle-related diseases, and circulating biomarkers reflecting these changes could have disease prognostic value. This study aimed to determine hepatic and systemic changes in TCA-cycle-related metabolites upon the selective pharmacologic enhancement of mitochondrial fatty acid β-oxidation in the liver, and to elucidate the mechanisms and potential markers of hepatic mitochondrial activity. Male Wistar rats were treated with 3-thia fatty acids (e.g., tetradecylthioacetic acid (TTA)), which target mitochondrial biogenesis, mitochondrial fatty acid β-oxidation, and ketogenesis predominantly in the liver. Hepatic and plasma concentrations of TCA cycle intermediates and anaplerotic substrates (LC-MS/MS), plasma ketones (colorimetric assay), and acylcarnitines (HPLC-MS/MS), along with associated TCA-cycle-related gene expression (qPCR) and enzyme activities, were determined. TTA-induced hepatic fatty acid β-oxidation resulted in an increased ratio of plasma ketone bodies/nonesterified fatty acid (NEFA), lower plasma malonyl-CoA levels, and a higher ratio of plasma acetylcarnitine/palmitoylcarnitine (C2/C16). These changes were associated with decreased hepatic and increased plasma pyruvate concentrations, and increased plasma concentrations of succinate, malate, and 2-hydroxyglutarate. Expression of several genes encoding TCA cycle enzymes and the malate–oxoglutarate carrier (Slc25a11), glutamate dehydrogenase (Gdh), and malic enzyme (Mdh1 and Mdh2) were significantly increased. In conclusion, the induction of hepatic mitochondrial fatty acid β-oxidation by 3-thia fatty acids lowered hepatic pyruvate while increasing plasma pyruvate, as well as succinate, malate, and 2-hydroxyglutarate. [ABSTRACT FROM AUTHOR]

Nitrogen is one of the most important nutrients for tea plants, as it contributes significantly to tea yield and serves as the component of amino acids, which in turn affects the quality of tea produced. To achieve higher yields, excessive amounts of N fertilizers mainly in the form of urea have been applied in tea plantations where N fertilizer is prone to convert to nitrate and be lost by leaching in the acid soils. This usually results in elevated costs and environmental pollution. A comprehensive understanding of N metabolism in tea plants and the underlying mechanisms is necessary to identify the key regulators, characterize the functional phenotypes, and finally improve nitrogen use efficiency (NUE). Tea plants absorb and utilize ammonium as the preferred N source, thus a large amount of nitrate remains activated in soils. The improvement of nitrate utilization by tea plants is going to be an alternative aspect for NUE with great potentiality. In the process of N assimilation, nitrate is reduced to ammonium and subsequently derived to the GS-GOGAT pathway, involving the participation of nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), glutamate synthase (GOGAT), and glutamate dehydrogenase (GDH). Additionally, theanine, a unique amino acid responsible for umami taste, is biosynthesized by the catalysis of theanine synthetase (TS). In this review, we summarize what is known about the regulation and functioning of the enzymes and transporters implicated in N acquisition and metabolism in tea plants and the current methods for assessing NUE in this species. The challenges and prospects to expand our knowledge on N metabolism and related molecular mechanisms in tea plants which could be a model for woody perennial plant used for vegetative harvest are also discussed to provide the theoretical basis for future research to assess NUE traits more precisely among the vast germplasm resources, thus achieving NUE improvement. [ABSTRACT FROM AUTHOR]