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Xylanibacter ruminicola is an abundant rumen bacterium that produces propionate in a cobalamin (vitamin B 12 )-dependent manner via the succinate pathway. However, the extent to which this occurs across ruminal Xylanibacter and closely related bacteria, and the effect of cobalamin supplementation on the expression of propionate pathway genes and enzymes has yet to be investigated. To assess this, we screened 14 strains and found that almost all strains produced propionate when supplemented with cobalamin. X. ruminicola KHP1 was selected for further study, including complete genome sequencing, and comparative transcriptomics and proteomics of KHP1 cultures grown with and without supplemented cobalamin. The complete KHP1 genome was searched for cobalamin-binding riboswitches and four were predicted, though none were closely located to any of the succinate pathway genes, which were dispersed at numerous genomic loci. Cobalamin supplementation led to the differential expression of 17.5% of genes, including genes encoding the cobalamin-dependent methylmalonyl-CoA mutase and some methylmalonyl-CoA decarboxylase subunits, but most propionate biosynthesis pathway genes were not differentially expressed. The effect of cobalamin supplementation on the KHP1 proteome was much less pronounced, with the only differentially abundant propionate pathway enzyme being methylmalonyl-CoA mutase, which had greater abundance when supplemented with cobalamin. Our results demonstrate that cobalamin supplementation does not result in induction of the entire propionate biosynthesis pathway, but consistently increased expression of methylmalonyl-CoA mutase at transcriptome and proteome levels. The magnitude of the differential expression of propionate pathway genes observed was minor compared to that of genes proximate to predicted cobalamin riboswitches., Importance: In ruminants, the rumen microbial community plays a critical role in nutrition through the fermentation of feed to provide vital energy substrates for the host animal. Propionate is a major rumen fermentation end-product and increasing its production is desirable given its importance in host glucose production and impact on greenhouse gas production. Vitamin B 12 (cobalamin) can induce propionate production in the prominent rumen bacterium Xylanibacter ruminicola , but it is not fully understood how cobalamin regulates propionate pathway activity. Contrary to expectation, we found that cobalamin supplementation had little effect on propionate pathway expression at transcriptome and proteome levels, with minor upregulation of genes encoding the cobalamin-dependent enzyme of the pathway. These findings provide new insights into factors that regulate propionate production and suggest that cobalamin-dependent propionate production by X. ruminicola is controlled post-translationally., Competing Interests: The authors declare no conflict of interest.

Traumatic brain injury is a highly irreversible process that consists of primary as well as secondary injury which develops and progresses over months to years, leading to cognitive dysfunctions. Vitamin B 12 received considerable interest due to its potential therapeutic properties. The pathways of vitamin B 12 are closely related to neuronal survival but its effects on the pathophysiology of injury with respect to cognition is a relatively unexplored area of research. In this study, we investigated, the effect of vitamin B 12 and its involvement in neuroprotection on TBI-induced pathophysiology in male Swiss albino mice. Our findings suggested that vitamin B 12 supplementation improves TBI-mediated neurological impairments, spatial and recognition memory, and anxiety-like behavior. Furthermore, the oxidative stress was reduced by declined homocysteine level with vitamin B 12 supplementation validating declined expression of astrocytes and TBI biomarkers. The studies on neuronal morphology revealed that vitamin B 12 supplementation increases the dendritic arborization and density of mushroom and filopodia-shaped spines and further increases the expression of synaptic plasticity-related genes and proteins. Taken together, our findings reveal that, supplementation of vitamin B 12 restored the TBI-induced downregulation of dendritic arborization, and spine density which ultimately increases synaptic plasticity, cell survival, and recovery of cognitive dysfunctions., Competing Interests: Declaration of competing interest The authors declare that there is no conflict of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Inflammatory diseases of the skin have a considerable high prevalence worldwide and negatively impact the patients' quality of life. First-line standard therapies for these conditions inherently entail important side effects when used long-term, particularly complicating the management of chronic cases. Therefore, there is a need to develop novel therapeutic strategies to offer reliable alternative treatments. Abnormally high reactive oxygen species (ROS) levels are characteristic of this kind of illnesses, and therefore a reasonable therapeutic goal. Cyanocobalamin, also known as Vitamin B 12 , possesses notable antioxidant and ROS-scavenging properties which could make it a possible therapeutic alternative. However, its considerable molecular weight restricts passive diffusion through the skin and forces the use of an advanced transdermal delivery system. Here, we present several prototypes of Cyanocobalamin-loaded Dissolving Microarray Patches (B 12 @DMAPs) with adequate mechanical properties to effectively penetrate the stratum corneum barrier, allowing drug deposition into the skin structure. Ex vivo penetration and permeability studies noted an effective drug presence within the dermal skin layers; in vitro compatibility studies in representative cell skin cell lines such as L929 fibroblasts and HaCaT keratinocytes ensured their safe use. The in vivo efficacy of the selected prototype was tested in a delayed-type hypersensitivity murine model that mimics an inflammatory skin process. Several findings such as a reduction of MPO-related photon emission in a bioluminescence study, protection against histological damage, and decrease of inflammatory cytokines levels point out the effectivity of B 12 @DMAPs to downregulate the skin inflammatory environment. Overall, B 12 @DMAPs offer a cost-effective translational alternative for improving patients' skin healthcare., Competing Interests: Declaration of competing interest The authors have no relevant financial or non-financial interests to disclose., (Copyright © 2024. Published by Elsevier B.V.)

The present study aimed to assess the potential effect of vitamin B 12 (Vit B 12 ) on cognition impairment caused by nicotine (Nic) cessation in adolescent male rats. Adolescent male rats were categorized into two main groups as vehicle (normal saline, intraperitoneally), and Nic group in which received Nic (2 mg/kg) from 21 to 42 days of ages and then the Nic group were divided into three groups as withdrawal (the animals returned to regular diet without treatment), second and third groups received bupropion (20 mg/kg), and Vit B 12 at three different doses including 0.5,1, and 1.5 mg/kg by oral gavage as treatments to attenuate Nic withdrawal symptoms. The last group including normal animals received the highest doses of Vit B 12 just in the Nic abstinence period to compare the effect of that with vehicle. In MWM, Vit B 12 and bupropion increased the time spent in the target quadrant that is strongly associated with spatial memory as well as the more time spent with the NORT. Vit B 12 and bupropion modulated both oxidant/antioxidant and inflammatory/anti-inflammatory balance, alongside inhibitory effect on AChE, and GFAP. However, BDNF and amyloid-B showed insignificant difference as compared to Vit B 12 and bupropion. Considering the present results and similar related studies, Vit B 12 can be introduced as a strong anti-oxidant, and anti-inflammatory agent by which probably improved memory impairment caused by Nic addiction accompanied by withdrawal. Further, other mechanisms including activity reduction of AChE, and GFAP should be considered; however, it needs further investigation and larger-scale evidences., Competing Interests: Declaration of Competing Interest There was no conflict of interest., (Copyright © 2024. Published by Elsevier B.V.)

Vitamin B12 is an essential nutritional co-factor for the folate and methionine cycles, which together constitute one-carbon metabolism. Here, we show that dietary uptake of vitamin B12 modulates cell fate decisions controlled by the conserved RAS/MAPK signaling pathway in C. elegans. A bacterial diet rich in vitamin B12 increases vulval induction, germ cell apoptosis and oocyte differentiation. These effects are mediated by different one-carbon metabolites in a tissue-specific manner. Vitamin B12 enhances via the choline/phosphatidylcholine metabolism vulval induction by down-regulating fat biosynthesis genes and increasing H3K4 tri-methylation, which results in increased expression of RAS/MAPK target genes. Furthermore, the nucleoside metabolism and H3K4 tri-methylation positively regulate germ cell apoptosis and oocyte production. Using mammalian cells carrying different activated KRAS and BRAF alleles, we show that the effects of methionine on RAS/MAPK-regulated phenotype are conserved in mammals. Our findings suggest that the vitamin B12-dependent one-carbon metabolism is a limiting factor for diverse RAS/MAPK-induced cellular responses., (© 2024. The Author(s).)

Inflammatory bowel diseases (IBDs) are immune chronic diseases characterized by recurrent episodes, resulting in continuous intestinal barrier damage and intestinal microbiota dysbiosis. Safe strategies aimed at stabilizing and reducing IBDs recurrence have been vigorously pursued. Here, we constructed a recurrent intestinal injury Drosophila model and found that vitamin B12 (VB12), an essential co-factor for organism physiological functions, could effectively protect the intestine and reduce dextran sulfate sodium-induced intestinal barrier disruption. VB12 also alleviated microbial dysbiosis in the Drosophila model and inhibited the growth of gram-negative bacteria. We demonstrated that VB12 could mitigate intestinal damage by activating the hypoxia-inducible factor-1 signaling pathway in injured conditions, which was achieved by regulating the intestinal oxidation. In addition, we also validated the protective effect of VB12 in a murine acute colitis model. In summary, we offer new insights and implications for the potential supportive role of VB12 in the management of recurrent IBDs flare-ups., (© 2024. The Author(s).)

Background: Insulin resistance during early lactation in goats has been a topic of interest for researchers, as addressing this issue can significantly improve their metabolic health., Objectives: To investigate the potential of butaphosphan and cyanocobalamin in controlling insulin resistance, we conducted a study with the hypothesis that this combination may mitigate insulin resistance in dairy goats., Methods: Ten adult goats were divided equally into two groups: Ctrl and B+C. The Ctrl group received 6 mL of normal saline, while the second group was administered 6 mL of 10% butaphosphan and 0.005% cyanocobalamin on days 21, 20, 19, and 12, 11, 10, and 3, 2, 1 before parturition. On the 10th and 20th days after parturition, blood samples were gathered to analyze the levels of different metabolites and evaluate insulin resistance/sensitivity through an intravenous glucose tolerance test and surrogate indices. Body condition scores, milk production, and weight gain of the kids were also recorded during the study., Results: Although the B+C group showed slightly higher insulin responsiveness than the Ctrl group in the intravenous glucose tolerance test, but the difference was insignificant. Comparably, no significant differences were noticed in the remaining metabolic indicators amidst the Ctrl and B+C groups., Conclusions: The lack of substantial differences can be attributed to the limited sample size and the prescribed drug dosage. Further investigations with higher doses exceeding 6 mL are warranted to explore potential effects. Additionally, species-specific differences in ruminants might exist, and caprine metabolism of the compound might differ from that of bovine and ovine. Consequently, we recommend conducting more studies in this field., (© 2024 The Author(s). Veterinary Medicine and Science published by John Wiley & Sons Ltd.)

Recently, we have described the first supermolecular nanoentities of vitamin B 12 derivative, viz. monocyano form of heptabutyl cobyrinate, unique nanoparticles with strong noncovalent intermolecular interactions, emerging optical and catalytic properties. Their nearest analogue, heptamethyl cobyrinate (ACCby), exhibits bioactivity. Here, we demonstrate the first example of the formation of nanoparticles of this nucleotide-free analogue of vitamin B 12 in protein nanocarriers and neuroprotective activity in vivo of the own nanoform of the drug. The preparation and characterization of nanocarriers based on bovine serum albumin (BSA) loaded with vitamin B 12 (viz. cyano- and aquacobalamins) and ACCby were performed. Nucleotide-free analogue of vitamin B 12 is tightly retained by the protein structure and exists in an incorporated state in the form of nanoparticles. The effect of encapsulated drugs on the character and severity of primary generalized seizures in rats induced by the pharmacotoxicant thiosemicarbazide was studied. Cyanocobalamin and ACCby exhibited a neuroprotective effect. The best influence of the encapsulation on the effectiveness of the drugs was achieved in the case of AСCby, whose bioavailability as a neuroprotector did not change upon introduction in BSA particles, i.e., 33 % of surviving animals were observed upon ACCby administration in free form and in encapsulated state. No surviving rats were observed without the administration of drugs. Thus, BSA nanocarriers loaded by nanoparticles of nucleotide-free analogues of vitamin B 12, including hydrophobic ones, can be recommended for neuroprotection and targeted delivery., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Larissa A. Maiorova reports financial support was provided by Russian Science Foundation. Larissa A. Maiorova reports financial support was provided by Ministry of Science and Higher Education of the Russian Federation. Larissa A. Maiorova reports a relationship with Federal Research Center Computer Science and Control of Russian Academy of Sciences that includes: employment. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The Burkholderia cepacia complex (Bcc) consists of opportunistic pathogens known to cause pneumonia in immunocompromised individuals, especially those with cystic fibrosis. Treating Bcc pneumonia is challenging due to the pathogens' high multidrug resistance. Therefore, inhalation therapy with tobramycin powder, which can achieve high antibiotic concentrations in the lungs, is a promising treatment option. In this study, we investigated potential mechanisms that could compromise the effectiveness of tobramycin therapy. By selecting for B. cenocepacia survivors against tobramycin, we identified three spontaneous mutations that disrupt a gene encoding a key enzyme in the biosynthesis of cobalamin (Vitamin B 12 ). This disruption may affect the production of succinyl-CoA by methylmalonyl-CoA mutase, which requires adenosylcobalamin as a cofactor. The depletion of cellular succinyl-CoA may impact the tricarboxylic acid (TCA) cycle, which becomes metabolically overloaded upon exposure to tobramycin. Consequently, the mutants exhibited significantly reduced reactive oxygen species (ROS) production. Both the wild-type and mutants showed tolerance to tobramycin and various other bactericidal antibiotics under microaerobic conditions. This suggests that compromised ROS-mediated killing, due to the impacted TCA cycle, underlies the mutants' tolerance to bactericidal antibiotics. The importance of ROS-mediated killing and the potential emergence of mutants that evade it through the depletion of cobalamin (Vitamin B 12 ) provide valuable insights for developing strategies to enhance antibiotic treatments of Bcc pneumonia.

Background: Vitamin B 12 is essential for deoxyribonucleic acid synthesis and genome stability. A deficiency of vitamin B 12 is associated with telomere shortening, genomic aging, and increased risk of chronic disease and mortality., Objectives: The study aims to determine the effect of vitamin B 12 supplementation on leukocyte telomere length (LTL) in infants at risk of vitamin B 12 deficiency., Methods: The study was a predefined secondary analysis of a randomized controlled trial enrolling 600 Nepalese infants aged 6 -11 mo, who were supplemented with 2 μg (2-3 recommended daily allowances) vitamin B 12 or placebo daily for 1 y. At the end of the study, LTL was measured in 497 participants. Mean LTL was compared between the treatment arms in the full sample and predefined subgroups based on markers of vitamin B 12 status, hemoglobin, sex, and growth indices., Results: LTL at end-study did not differ between the vitamin B 12 and placebo arm with a standardized mean difference (95% confidence interval) of 0.04 (-0.14, 0.21). There was no effect of vitamin B 12 on LTL in any of the subgroups., Conclusions: Providing daily vitamin B 12 for 1 y during infancy in a population at risk of vitamin B 12 deficiency does not affect LTL. This trial was registered at clinicaltrials.gov as NCT02272842., (Copyright © 2023 American Society for Nutrition. Published by Elsevier Inc. All rights reserved.)

In humans, a neomorphic isocitrate dehydrogenase mutation ( idh-1neo ) causes increased levels of cellular D-2-hydroxyglutarate (D-2HG), a proposed oncometabolite. However, the physiological effects of increased D-2HG and whether additional metabolic changes occur in the presence of an idh-1neo mutation are not well understood. We created a Caenorhabditis elegans model to study the effects of the idh-1neo mutation in a whole animal. Comparing the phenotypes exhibited by the idh-1neo to ∆dhgd-1 (D-2HG dehydrogenase) mutant animals, which also accumulate D-2HG, we identified a specific vitamin B12 diet-dependent vulnerability in idh-1neo mutant animals that leads to increased embryonic lethality. Through a genetic screen, we found that impairment of the glycine cleavage system, which generates one-carbon donor units, exacerbates this phenotype. In addition, supplementation with alternate sources of one-carbon donors suppresses the lethal phenotype. Our results indicate that the idh-1neo mutation imposes a heightened dependency on the one-carbon pool and provides a further understanding of how this oncogenic mutation rewires cellular metabolism., (© 2024 Ponomarova et al.)

Phthiocerol dimycocerosate (PDIM) is an essential virulence lipid of Mycobacterium tuberculosis. In vitro culturing rapidly selects for spontaneous PDIM-negative mutants that have attenuated virulence and increased cell wall permeability, thus impacting the relevance of experimental findings. PDIM loss can also reduce the efficacy of the BCG Pasteur vaccine. Here we show that vancomycin susceptibility can rapidly screen for M. tuberculosis PDIM production. We find that metabolic deficiency of methylmalonyl-CoA impedes the growth of PDIM-producing bacilli, selecting for PDIM-negative variants. Supplementation with odd-chain fatty acids, cholesterol or vitamin B 12 restores PDIM-positive bacterial growth. Specifically, we show that propionate supplementation enhances PDIM-producing bacterial growth and selects against PDIM-negative mutants, analogous to in vivo conditions. Our study provides a simple approach to screen for and maintain PDIM production, and reveals how discrepancies between the host and in vitro nutrient environments can attenuate bacterial pathogenicity., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Genetic aberrations of the maternal UBE3A allele, which encodes the E3 ubiquitin ligase E6AP, are the cause of Angelman syndrome (AS), an imprinting disorder. In most cases, the maternal UBE3A allele is not expressed. Yet, approximately 10 percent of AS individuals harbor distinct point mutations in the maternal allele resulting in the expression of full-length E6AP variants that frequently display compromised ligase activity. In a high-throughput screen, we identified cyanocobalamin, a vitamin B12-derivative, and several alloxazine derivatives as activators of the AS-linked E6AP-F583S variant. Furthermore, we show by cross-linking coupled to mass spectrometry that cobalamins affect the structural dynamics of E6AP-F583S and apply limited proteolysis coupled to mass spectrometry to obtain information about the regions of E6AP that are involved in, or are affected by binding cobalamins and alloxazine derivatives. Our data suggest that dietary supplementation with vitamin B12 can be beneficial for AS individuals., (© 2024 The Authors. ChemBioChem published by Wiley-VCH GmbH.)

Biotin (BI) and cobalamin (CA) are essential for rumen propionate production and hepatic gluconeogenesis. The study evaluated the influence of BI or/and coated CA (CCA) on milk performance and nutrient digestion in cows. Sixty Holstein dairy cows were assigned in a 2 × 2 factorial arrangement and randomised block design to four groups. The factors were BI at 0 or 20 mg/day and CCA at 0 or 9 mg CA/day. Dry matter intake increased with BI addition but was unchanged with CCA supply. Addition of BI or CCA increased fat-corrected milk, milk fat and milk protein yields and feed efficiency. Moreover, lactose yield was increased by CCA addition. Dry matter, organic matter, crude protein and acid detergent fibre total-tract digestibility increased for BI or CCA supply. When CCA was supplemented, positive response of neutral detergent fibre digestibility to BI addition was enhanced. Supplementing BI did not affect pH, propionate content and acetate to propionate ratio, but increased total volatile fatty acids (VFA) and acetate contents. Supplementing CCA decreased pH and acetate to propionate ratio, but increased total VFA, acetate and propionate contents. Rumen protease and carboxymethyl-cellulase activities and fungi, bacteria and Butyrivibrio fibrisolvens numbers increased for BI or CCA supply. In addition, protozoa increased for BI addition, and protease activity and Prevotella ruminicola increased for CCA supply. When CCA was supplemented, positive responses of R. albus and Ruminobacter amylophilus numbers to BI addition were enhanced. Blood glucose concentration was unchanged with BI supply, but increased for CCA supply. Blood nonesterified fatty acids and β-hydroxybutyrate contents reduced with BI or CCA supply. Supplementation with BI or CCA increased blood BI or CA content. The results showed that supplementing BI or/and CCA improved lactation performance and nutrient digestion, and CCA supply did not enhance the lactation performance response to BI supply., (© 2024 Wiley‐VCH GmbH. Published by John Wiley & Sons Ltd.)

Vitamin B 12 is a group of biologically active cobalamin compounds. In this study, we investigated the inhibitory effects of methylcobalamin (MeCbl) and hydroxocobalamin acetate (OHCbl Acetate) on protein tyrosine phosphatase 1B (PTP1B). MeCbl and OHCbl Acetate exhibited an IC 50 of approximately 58.390 ± 2.811 μM and 8.998 ± 0.587 μM, respectively. The K i values of MeCbl and OHCbl Acetate were 25.01 μM and 4.04 μM respectively. To elucidate the inhibition mechanism, we conducted a 500 ns Gaussian accelerated molecular dynamics (GaMD) simulation. Utilizing PCA and tICA, we constructed Markov state models (MSM) to examine secondary structure changes during motion. Our findings revealed that the α-helix at residues 37-42 remained the most stable in the PTP1B-OHCbl Acetate system. Furthermore, upon binding of OHCbl Acetate or MeCbl, the WPD loop of PTP1B moved inward to the active pocket, forming a closed conformation and potentially obstructs substrate entry. Protein-ligand interaction analysis and MM-PBSA showed that OHCbl Acetate exhibited lower binding free energy and engaged in more residue interactions with PTP1B. In summary, our study confirmed the substantial inhibitory activity of OHCbl Acetate against PTP1B, with its inhibitory potency notably surpassing that of MeCbl. We demonstrated potential molecular mechanisms of OHCbl Acetate inhibiting PTP1B., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Methionine dependence is a characteristic of most cancer cells where they are unable to proliferate when the essential amino acid methionine is replaced with its precursor homocysteine in the growing media. Normal cells, on the other hand, thrive under these conditions and are referred to as methionine-independent. The reaction that adds a methyl group from 5-methyltetrahydrofolate to homocysteine to regenerate methionine is catalyzed by the enzyme methionine synthase with the cofactor cobalamin (vitamin B 12 ). However, decades of research have shown that methionine dependence in cancer is not due to a defect in the activity of methionine synthase. Cobalamin metabolism has been tied to the dependent phenotype in rare cell lines. We have identified a human colorectal cancer cell line in which the cells regain the ability to proliferation in methionine-free, L-homocystine-supplemented media when cyanocobalamin is supplemented at a level of 1 µg/mL. In human SW48 cells, methionine replacement with L-homocystine does not induce any measurable increase in apoptosis or reactive oxygen species production in this cell line. Rather, proliferation is halted, then restored in the presence of cyanocobalamin. Our data show that supplementation with cyanocobalamin prevents the activation of the integrated stress response (ISR) in methionine-deprived media in this cell line. The ISR-associated cell cycle arrest, characteristic of methionine-dependence in cancer, is also prevented, leading to the continuation of proliferation in methionine-deprived SW48 cells with cobalamin. Our results highlight differences between cancer cell lines in the response to cobalamin supplementation in the context of methionine dependence.

Listeria monocytogenes is a facultative anaerobe which can cause a severe food-borne infection known as listeriosis. L. monocytogenes is capable of utilizing various nutrient sources including rhamnose, a naturally occurring deoxy sugar abundant in foods. L. monocytogenes can degrade rhamnose into lactate, acetate and 1,2-propanediol. Our previous study showed that addition of vitamin B 12 stimulated anaerobic growth of L. monocytogenes on rhamnose due to the activation of bacterial microcompartments for 1,2-propanediol utilization (pdu BMC) with concomitant production of propionate and propanol. Notably, anaerobic 1,2-propanediol metabolism has been linked to virulence of enteric pathogens including Salmonella spp. and L. monocytogenes. In this study we investigated the impact of B 12 and BMC activation on i) aerobic and anerobic growth of L. monocytogenes on rhamnose and ii) the level of virulence. We observed B 12 -induced pdu BMC activation and growth stimulation only in anaerobically grown cells. Comparative Caco-2 virulence assays showed that these pdu BMC-induced cells have significantly higher translocation efficiency compared to non-induced cells (anaerobic growth without B 12 ; aerobic growth with or without B 12 ), while adhesion and invasion capacity is similar for all cells. Comparative proteome analysis showed specific and overlapping responses linked to metabolic shifts, activation of stress defense proteins and virulence factors, with RNA polymerase sigma factor SigL, teichoic acid export ATP-binding protein TagH, DNA repair and protection proteins, RadA and DPS, and glutathione synthase GshAB, previously linked to activation of virulence response in L. monocytogenes, uniquely upregulated in anaerobically rhamnose grown pdu-induced cells. Our results shed light on possible effects of B 12 on L. monocytogenes competitive fitness and virulence activation when utilizing rhamnose in anaerobic conditions encountered during transmission and the human intestine., Competing Interests: Declaration of competing interest The authors have no affiliation with any organization with a direct or indirect financial interest in the subject matter discussed in the manuscript., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Subacute combined degeneration (SCD) of the spinal cord is a disease involving the lateral and posterior columns of the spinal cord that can manifest in patients with vitamin B12 deficiency. Nitrous oxide (N2O)-induced SCD of the spinal cord is a result of N2O interfering with the metabolism of vitamin B12 and results in nervous system demyelination. This is an infrequent complication of N2O anesthesia; however, cases are rising with recreational N2O use. This case report describes a patient with SCD of the spinal cord induced by recreational N2O abuse. The patient presented to a spine surgery clinic with a 3-week history of progressive global weakness and paresthesias. After a detailed history and physical examination, the diagnosis was made and supported by various tests and imaging findings. Despite marked neurologic deficits, the patient's symptoms improved markedly with therapy and vitamin B12 supplementation. Spine surgery clinicians may be confronted with these cases and should be aware of this atypical presentation of SCD. As in our case, patients may present with neurologic deficits of unclear etiology. Neurologic dysfunction may be irreversible; therefore, accurate diagnosis, medical treatment, and complete neurologic evaluation are of the utmost importance to prevent additional progression., (Copyright © 2024 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Orthopaedic Surgeons.)

Chronic hyperglycemia-induced neuropathological changes include neuronal apoptosis, astrogliosis, decrease in neurotrophic support, impaired synaptic plasticity, and impaired protein quality control (PQC) system. Vitamin B12 is indispensable for neuronal development and brain function. Several studies reported the neuroprotective effect of B12 supplementation in diabetic patients. However, the underlying molecular basis for the neuroprotective effect of B12 supplementation in diabetes needs to be thoroughly investigated. Two-month-old Sprague-Dawley rats were randomly assigned into three groups: Control (CN), diabetes (D; induced with streptozotocin; STZ), and diabetic rats supplemented with vitamin B12 (DBS; vitamin B12; 50 μg/kg) for four months. At the end of 4 months of experimentation, the brain was dissected to collect the cerebral cortex (CC). The morphology of CC was investigated with H&E and Nissl body staining. Neuronal apoptosis was determined with TUNEL assay. The components of neurotrophic support, astrogliosis, synaptic plasticity, and PQC processes were investigated by immunoblotting and immunostaining methods. H& E, Nissl body, and TUNEL staining revealed that diabetes-induced neuronal apoptosis and degeneration. However, B12 supplementation ameliorated the diabetes-induced neuronal apoptosis. Further, B12 supplementation restored the markers of neurotrophic support (BDNF, NGF, and GDNF), and synaptic plasticity (SYP, and PSD-95) in diabetic rats. Interestingly, B12 supplementation also attenuated astrogliosis, ER stress, and ameliorated autophagy-related proteins in diabetic rats. Overall, these findings suggest that B12 acts as a neuroprotective agent by inhibiting the neuropathological changes in STZ-induced type 1 diabetes. Thus, B12 supplementation could produce beneficial outcomes including neuroprotective effects in diabetic patients., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

We hypothesized that restricted maternal nutrition and supplementation of one-carbon metabolites (OCM; methionine, folate, choline, and vitamin B12) would affect placental vascular development during early pregnancy. A total of 43 cows were bred, and 32 heifers successfully became pregnant with female calves, leading to the formation of four treatment groups: CON - OCM (n = 8), CON + OCM (n = 7), RES - OCM (n = 9), and RES + OCM (n = 8). The experimental design was a 2 × 2 factorial, with main factors of dietary intake affecting average daily gain: control (CON; 0.6 kg/d ADG) and restricted (RES; -0.23 kg/d ADG); and OCM supplementation (+OCM) in which the heifers were supplemented with rumen-protected methionine (7.4 g/d) and choline (44.4 g/d) and received weekly injections of 320 mg of folate and 20 mg of vitamin B12, or received no supplementation (-OCM; corn carrier and saline injections). Heifers were individually fed and randomly assigned to treatment at breeding (day 0). Placentomes were collected on day 63 of gestation (0.225 of gestation). Fluorescent staining with CD31 and CD34 combined with image analysis was used to determine the vascularity of the placenta. Images were analyzed for capillary area density (CAD) and capillary number density (CND). Areas evaluated included fetal placental cotyledon (COT), maternal placental caruncle (CAR), whole placentome (CAR + COT), intercotyledonary fetal membranes (ICOT, or chorioallantois), intercaruncular endometrium (ICAR), and endometrial glands (EG). Data were analyzed with the GLM procedure of SAS, with heifer as the experimental unit and significance at P ≤ 0.05 and a tendency at P > 0.05 and P < 0.10. Though no gain × OCM interactions existed (P ≥ 0.10), OCM supplementation increased (P = 0.01) CAD of EG, whereas nutrient restriction tended (P < 0.10) to increase CAD of ICOT and CND of COT. Additionally, there was a gain × OCM interaction (P < 0.05) for CAD within the placentome and ICAR, such that RES reduced and supplementation of RES with OCM restored CAD. These results indicate that maternal rate of gain and OCM supplementation affected placental vascularization (capillary area and number density), which could affect placental function and thus the efficiency of nutrient transfer to the fetus during early gestation., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The objective of this study was to determine the dose-dependent response of one-carbon metabolite (OCM: methionine, choline, folate, and vitamin B12) supplementation on heifer dry matter intake on fixed gain, organ mass, hematology, cytokine concentration, pancreatic and jejunal enzyme activity, and muscle hydrogen peroxide production. Angus heifers (n = 30; body weight [BW] = 392.6 ± 12.6 kg) were individually fed and assigned to one of five treatments: 0XNEG: total mixed ration (TMR) and saline injections at days 0 and 7 of the estrous cycle, 0XPOS: TMR, rumen-protected methionine (MET) fed at 0.08% of the diet dry matter, rumen-protected choline (CHOL) fed at 60 g/d, and saline injections at days 0 and 7, 0.5X: TMR, MET, CHOL, 5-mg B12, and 80-mg folate injections at days 0 and 7, 1X: TMR, MET CHOL, 10-mg vitamin B12, and 160-mg folate at days 0 and 7, and 2X: TMR, MET, CHOL, 20-mg vitamin B12, and 320-mg folate at days 0 and 7. All heifers were estrus synchronized but not bred, and blood samples were collected on days 0, 7, and at slaughter (day 14) during which tissues were collected. By design, heifer ADG did not differ (P = 0.96). Spleen weight and uterine weight were affected cubically (P = 0.03) decreasing from 0XPOS to 0.5X. Ovarian weight decreased linearly (P < 0.01) with increasing folate and B12 injection. Hemoglobin and hematocrit percentage were decreased (P < 0.01) in the 0.5X treatment compared with all other treatments. Plasma glucose, histotroph protein, and pancreatic α-amylase were decreased (P ≤ 0.04) in the 0.5X treatment. Heifers on the 2X treatment had greater pancreatic α-amylase compared with 0XNEG and 0.5X treatment. Interleukin-6 in plasma tended (P = 0.08) to be greater in the 0XPOS heifers compared with all other treatments. Lastly, 0XPOS-treated heifers had reduced (P ≤ 0.07) hydrogen peroxide production in muscle compared with 0XNEG heifers. These data imply that while certain doses of OCM do not improve whole animal physiology, OCM supplementation doses that disrupt one-carbon metabolism, such as that of the 0.5X treatment, can induce a negative systemic response that results in negative effects in both the dam and the conceptus during early gestation. Therefore, it is necessary to simultaneously establish an optimal OCM dose that increases circulating concentrations for use by the dam and the conceptus, while avoiding potential negative side effects of a disruptive OCM, to evaluate the long-term impacts of OCM supplementation of offspring programming., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society of Animal Science.)

Aim: To evaluate the effects of methylprednisolone and vitamin B12 injection on the regeneration of the nerves after a mental nerve crush injury., Material and Methods: A total of 40 albino Wistar rats have been randomly divided into four groups: group 1 (n=10): crushlike nerve damage was created by pinching the left mental nerve for 60 s with an aneurysm clip and intraperitoneally administered 1 ml of saline for 14 days; group 2 (n=10): the left mental nerve was pinched for 60 s with an aneurysm clip and intraperitoneally administered 2 mg/kg of methylprednisolone for 14 days; group 3, experimental group (n=10): the left mental nerve was pinched for 60 s with an aneurysm clip and intraperitoneally administered 2 mg/kg of vitamin B12 for 14 days; and group 4, experimental group (n=10): the left mental nerve was pinched for 60 s and intraperitoneally administered 2 mg/kg of methylprednisolone and 2 mg/kg of vitamin B12 for 14 days. All rats were sacrificed on the 28th postoperative day, and histopathological evaluation was performed., Results: Nerve damage was higher in the control group than in other groups (p < 0.05). When Neural Cell Adhesion Molecule (NCAM) expression levels were compared, no major differences were observed between the methylprednisolone and control groups (p > 0.05). The B12 and B12+methylprednisolone groups reached significantly higher NCAM expression levels compared to the control and methylprednisolone groups. When the myelin basic protein (MBP) expression levels were compared (p < 0.05), the MBP expression was significantly higher in all experimental groups than in the control group (p < 0.05)., Conclusion: Systemic vitamin B12 and methylprednisolone administration effectively supported remyelination in the crushed mental nerve by increasing Schwann cell proliferation and differentiation.

Background: Cisplatin is an effective synthetic chemotherapeutic drug used for cancer treatment. Vitamin B12 has been shown to possess anti-genotoxic activity. This study aimed to investigate the effect of vitamin B12 on chromosomal damage induced by cisplatin., Methods: The level of sister chromatid exchanges (SCEs) and chromosomal aberrations (CAs) were measured in cultured human blood lymphocytes treated with cisplatin and/or vitamin B12., Results: The results showed a significantly elevated frequency of CAs and SCEs of cisplatin-treated cultures compared to the control (P < 0.05). The CAs and SCEs induced by cisplatin were significantly lowered by pretreatment of cell cultures with vitamin B12. In addition, cisplatin caused a slight reduction in the mitotic index (MI), while vitamin B12 did not modulate the effect of cisplatin on MI., Conclusion: Vitamin B12 can protect human lymphocytes against genotoxicity associated with cisplatin., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Since propionate exerts several physiological effects, maintenance of its normal colonic fermentation is essential. To investigate whether vitamin B 12 (VB 12 ) is essential for normal propionate fermentation by colonic bacteria, via the succinate pathway, we examined if high-amylose cornstarch (HACS) feeding activated such a pathway, if high HACS feeding impaired propionate fermentation, and if oral VB 12 supplementation normalized propionate fermentation. Male rats were given control, 20% HACS or 3% fucose diets (Expt. 1); a VB 12 -free control diet or one supplemented with 5-30% HACS (Expt. 2); and the 20% HACS diet supplemented with 0.025-25 mg/kg of VB 12 (Expt. 3), for 14 d. HACS feeding significantly increased cecal succinate concentration, activating the succinate pathway (Expt. 1). Cecal cobalamin concentration in 20% and 30% HACS groups was about 75% of that in the control group (Expt. 2). Cecal succinate and propionate concentrations significantly increased and decreased in 30% HACS groups, respectively, compared with the control group. Although HACS group supplemented with 0.025 mg/kg of VB 12 had a low concentration of cecal propionate, adding high amounts of VB 12 to HACS diets provided sufficient amounts of VB 12 to rat ceca and increased cecal propionate concentration (Expt. 3). Compared with the non-HACS group, the relative abundance of Akkermansia muciniphila, but not Bacteroides/Phocaeicola, was lower in the HACS counterpart and showed improvement with increased VB 12 doses. To summarize, feeding high HACS decreased and increased cecal VB 12 and succinate concentrations, respectively. Furthermore, colonic delivery of sufficient amounts of VB 12 to rats likely reduced accumulation of succinate and normalized propionate fermentation.

This study aimed to determine phosphorus and vitamin B12 supplementation effect in semen extender on the quality and fertility ability of chilled Thai native rooster semen. Eighty-four ejaculates of semen from 26 Thai native roosters (Burmese × Vietnam crossbreed) were included. Semen was collected by applying dorsal-abdominal massage once a week, pooled, diluted to 500 million sperms per dose, and divided into 6 groups. The semen samples used for control group were diluted with modified Beltsville poultry semen extender (BPSE). For the treatment groups 2 to 6: semen samples were diluted with modified BPSE and enriched with phosphorus and vitamin B12 (Octafos Octa Memorial Co., Ltd., Bangkok, Thailand) at concentrations 0.02, 0.04, 0.06, 0.08, and 0.10%. Semen fertility ability was tested in 6 replications by inseminating layer hens. Thirty-six Thai native hens were randomly assigned to 3 groups (control, 0.04, and 0.08%) of 12 hens and were inseminated with a dose of 0.2 mL on collecting day. Sperm motion characteristics (i.e., sperm motility, sperm progressive motility, and sperm kinetic parameters) were measured using a computer-assisted sperm analysis system (SCA, Proiser S.L., Valencia, Spain). Sperm viability, mitochondrial activity, acrosome integrity, plasma membrane integrity, and malondialdehyde (MDA) concentration were also evaluated. The sperm motion characteristics were the highest in the 0.04% supplementation group on all days of collection, especially the VCL and VAP (P < 0.05). The viability, mitochondrial activity, plasma membrane and acrosome integrity of spermatozoa were greater in the 0.04% supplementation group than in the control groups (P < 0.05). The 0.04% supplementation group had the lowest MDA concentration in all days of collection. The 0.04% supplementation group were higher both fertility (66.59 vs. 48.50%: P < 0.05) and hatching rates (58.80 vs. 43.18%: P < 0.05) than in the control group. In conclusion, 0.04% phosphorus and vitamin B12 concentrations supplementation in semen extender improved rooster semen quality and fertility in chilled rooster semen., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Vitamin B 12 (B 12 ) deficiency causes neurological manifestations resembling multiple sclerosis (MS); however, a molecular explanation for the similarity is unknown. FTY720 (fingolimod) is a sphingosine 1-phosphate (S1P) receptor modulator and sphingosine analog approved for MS therapy that can functionally antagonize S1P 1 . Here, we report that FTY720 suppresses neuroinflammation by functionally and physically regulating the B 12 pathways. Genetic and pharmacological S1P 1 inhibition upregulates a transcobalamin 2 (TCN2)-B 12 receptor, CD320, in immediate-early astrocytes (ieAstrocytes; a c-Fos-activated astrocyte subset that tracks with experimental autoimmune encephalomyelitis [EAE] severity). CD320 is also reduced in MS plaques. Deficiency of CD320 or dietary B 12 restriction worsens EAE and eliminates FTY720's efficacy while concomitantly downregulating type I interferon signaling. TCN2 functions as a chaperone for FTY720 and sphingosine, whose complex induces astrocytic CD320 internalization, suggesting a delivery mechanism of FTY720/sphingosine via the TCN2-CD320 pathway. Taken together, the B 12 -TCN2-CD320 pathway is essential for the mechanism of action of FTY720., Competing Interests: Declaration of interests J.C. has received honoraria, consulting fees, and funding support from Novartis, Bristol-Myers Squibb (Celgene), Biogen, and Janssen Pharmaceuticals. J.C. has an employment relationship with Neurocrine Biosciences, Inc., a company that may potentially benefit from the research results. Dr. Chun’s relationship with Neurocrine Biosciences, Inc. has been reviewed and approved by Sanford Burnham Prebys Medical Discovery Institute in accordance with its conflict of interest policies. D.J. is currently employed by Radionetics Oncology. A.G. is currently affiliated with University of California, Los Angeles. R.M. is currently affiliated with Loyola University Chicago. A.S. is currently affiliated with University of Wisconsin-Milwaukee. R.R. is currently employed by 8five8 Therapeutics., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Prolonged metformin treatment decreases vitamin B12 (B12) levels, whereas low B12 is associated with dyslipidaemia. Some studies have reported that metformin has no effect on intrahepatic triglyceride (TG) levels. Although AMP-activated protein kinase (AMPK) activation via adiponectin lowers hepatic TG content, its role in B12 deficiency and metformin has not been explored. We investigated whether low B12 impairs the beneficial effect of metformin on hepatic lipid metabolism via the AMPK-adiponectin axis. Methods : HepG2 was cultured using custom-made B12-deficient Eagle's Minimal Essential Medium (EMEM) in different B12-medium concentrations, followed by a 24-h metformin/adiponectin treatment. Gene and protein expressions and total intracellular TG were measured, and radiochemical analysis of TG synthesis and seahorse mitochondria stress assay were undertaken. Results : With low B12, total intracellular TG and synthesized radiolabelled TG were increased. Regulators of lipogenesis, cholesterol and genes regulating fatty acids (FAs; TG; and cholesterol biosynthesis were increased. FA oxidation (FAO) and mitochondrial function were decreased, with decreased pAMPKα and pACC levels. Following metformin treatment in hepatocytes with low B12, the gene and protein expression of the above targets were not alleviated. However, in the presence of adiponectin, intrahepatic lipid levels with low B12 decreased via upregulated pAMPKα and pACC levels. Again, combined adiponectin and metformin treatment ameliorated the low B12 effect and resulted in increased pAMPKα and pACC, with a subsequent reduction in lipogenesis, increased FAO and mitochondrion function. Conclusions : Adiponectin co-administration with metformin induced a higher intrahepatic lipid-lowering effect. Overall, we emphasize the potential therapeutic implications for hepatic AMPK activation via adiponectin for a clinical condition associated with B12 deficiency and metformin treatment.

Background: The present study aims to assess the effect of vitamin B 12 (Vit B 12 ) on depression-like behavior caused by nicotine (Nic) withdrawal, which is more likely due to the anxiogenic effect of Nic in adolescent male rats, through assessing behavioral and biochemical analysis., Methods: Adolescent male rats were divided into vehicle (received normal saline), and experimental groups that received Nic (2 mg/kg, intraperitoneally (i.p.)) for three consecutive weeks and after that, the group that received normal saline was divided into two groups, one of which returned to a regular diet, and the second one received Vit B 12 (1.5 mg/kg). The Nic group was divided into five groups, one of which received bupropion (Bup, 20 mg/kg), three of which received different doses of Vit B 12 (0.5, 1, and 1.5 mg/kg), and the last one returned to a normal diet without treatment, which was considered as the withdrawal period., Results: Behavioral analysis showed that Nic withdrawal induced anxiety and depression. Vit B 12 and Bup reduced anxiety and depression induced by Nic withdrawal. The biochemical analysis demonstrated the more activity of oxidative stress factors and pro-inflammatory cytokines in which Nic was administered, whereas both Vit B 12 and Bup reversed the results and improved the activity of both antioxidant and anti-inflammatory parameters. Furthermore, both serum and cortical Vit B 12 levels dramatically decreased in nicotine group, whereas treatment with both Vit B 12 and Bup as desirable treatments corrected Vit B 12 levels., Conclusion: According to the present findings, the results revealed that Vit B 12 is comparable with Bup in attenuation of Nic withdrawal symptoms. In addition, both Bup and Vit B 12 improved the decreased serum and cortical levels of Vit B 12 , which caused by nicotine. Administration of Vit B 12 in normal animals demonstrated better results in reducing antioxidant and anti-inflammatory parameters, which explores new hope to introduce Vit B 12 as a novel antioxidant and anti-inflammatory agent to treat not only withdrawal, but also other diseases related to the prominent role of oxidative stress or inflammatory pathways, such as Alzheimer's disease., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Vitamin B12 is a micronutrient required by a variety of organisms for healthy cellular functioning. Despite the systemic effects observed in cases of B12 deficiency, relatively little is known about how vitamin B12 affects immune health, especially in amphibians, which are declining at unprecedented rates. In this study, we tested how supplementing an algae diet with B12 affects the innate and adaptive immunity of Cuban tree frog (Osteopilus septentrionalis) tadpoles. We found that innate immunity, as measured by a bacterial killing assay, was significantly more robust in B12-supplemented tadpoles than control tadpoles, but no significant differences were found in natural antibody production or hematocrit between groups. Adaptive immunity, as measured by Aeromonas hydrophila-specific IgY antibodies, was significantly greater in tadpoles challenged with A. hydrophila and supplemented with B12 than in control tadpoles, those only challenged with A. hydrophila, and those only given B12. Our results suggest that vitamin B12 is an important factor in maintaining a functional immune system in tadpoles, which may also be true for all vertebrates., (© 2023 Wiley Periodicals LLC.)

Cerebral ischemia-reperfusion injury (CIRI) is often accompanied by upregulation of homocysteine (Hcy). Excessive Hcy damages cerebral vascular endothelial cells and neurons, inducing neurotoxicity and even neurodegeneration. Normally, supplementation of vitamin B 12 is an ideal intervention to reduce Hcy. However, vitamin B 12 therapy is clinically inefficacious for CIRI. Considering oxidative stress is closely related to CIRI, the lysosome is the pivotal site for vitamin B 12 transport. Lysosomal oxidative stress might hinder the transport of vitamin B 12 . Whether lysosomal malondialdehyde (lysosomal MDA), as the authoritative biomarker of lysosomal oxidative stress, interferes with the transport of vitamin B 12 has not been elucidated. This is ascribed to the absence of effective methods for real-time and in situ measurement of lysosomal MDA within living brains. Herein, a fluorescence imaging agent, Lyso-MCBH, was constructed to specifically monitor lysosomal MDA by entering the brain and targeting the lysosome. Erupting the lysosomal MDA level in living brains of mice under CIRI was first observed using Lyso-MCBH. Excessive lysosomal MDA was found to affect the efficacy of vitamin B 12 by blocking the transport of vitamin B 12 from the lysosome to the cytoplasm. More importantly, the expression and function of the vitamin B 12 transporter LMBD1 were proved to be associated with excessive lysosomal MDA. Altogether, the revealing of the lysosomal MDA-LMBD1 axis provides a cogent interpretation of the inefficacy of vitamin B 12 in CIRI, which could be a prospective therapeutic target.

High glucose levels can lead to the apoptosis of islet β cells, while autophagy can provide cytoprotection and promote autophagic cell death. Vitamin B12, a water-soluble B vitamin, has been shown to regulate insulin secretion and increase insulin sensitivity. However, the precise mechanism of action remains unclear. In this study, we investigated the influence of vitamin B12 on high glucose-induced apoptosis and autophagy in RIN-m5F cells to elucidate how vitamin B12 modulates insulin release. Our results demonstrate that exposure to 45 mM glucose led to a significant increase in the apoptosis rate of RIN-m5F cells. The treatment with vitamin B12 reduced the apoptosis rate and increased the number of autophagosomes. Moreover, vitamin B12 increased the ratio of microtubule-associated protein 1 light chain 3 beta to microtubule-associated protein 1 light chain 3 alpha (LC3-II/LC3-I), while decreasing the amount of sequestosome 1 (p62) and inhibiting the phosphorylation of p70 ribosomal protein S6 kinase (p70S6K) under both normal- and high-glucose conditions. The additional experiments revealed that vitamin B12 inhibited high glucose-induced apoptosis. Notably, this protective effect was attenuated when the autophagy inhibitor 3-methyladenine was introduced. Our findings suggest that vitamin B12 protects islet β cells against apoptosis induced by high glucose levels, possibly by inducing autophagy.

Methionine synthases (MetH) catalyse the methylation of homocysteine (Hcy) with 5-methyl-tetrahydrofolate (5, methyl-THF) acting as methyl donor, to form methionine (Met) and tetrahydrofolate (THF). This function is performed by two unrelated classes of enzymes that differ significantly in both their structures and mechanisms of action. The genomes of plants and many fungi exclusively encode cobalamin-independent enzymes (EC.2.1.1.14), while some fungi also possess proteins from the cobalamin-dependent (EC.2.1.1.13) family utilised by humans. Methionine synthase's function connects the methionine and folate cycles, making it a crucial node in primary metabolism, with impacts on important cellular processes such as anabolism, growth and synthesis of proteins, polyamines, nucleotides and lipids. As a result, MetHs are vital for the viability or virulence of numerous prominent human and plant pathogenic fungi and have been proposed as promising broad-spectrum antifungal drug targets. This review provides a summary of the relevance of methionine synthases to fungal metabolism, their potential as antifungal drug targets and insights into the structures of both classes of MetH., (© 2023 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.)

Aging results in more health challenges, including neurodegeneration. Healthy aging is possible through nutrition as well as other lifestyle changes. One-carbon (1C) metabolism is a key metabolic network that integrates nutritional signals with several processes in the human body. Dietary supplementation of 1C components, such as folic acid, vitamin B12, and choline are reported to have beneficial effects on normal and diseased brain function. The aim of this review is to summarize the current clinical studies investigating dietary supplementation of 1C, specifically folic acid, choline, and vitamin B12, and its effects on healthy aging. Preclinical studies using model systems have been included to discuss supplementation mechanisms of action. This article will also discuss future steps to consider for supplementation. Dietary supplementation of folic acid, vitamin B12, or choline has positive effects on normal and diseased brain function. Considerations for dietary supplementation to promote healthy aging include using precision medicine for individualized plans, avoiding over-supplementation, and combining therapies.

Aim: To examine the protective effect of vitamin B12 against myocardial ischemia/reperfusion (I/R) injury and elucidate its underlying mechanism of action., Methods: Mice were subjected to myocardial I/R injury by left anterior descending coronary artery (LAD) occlusion followed by 24 h reperfusion. Cardiac function and injury were evaluated by echocardiography, triphenyl tetrazolium chloride (TTC) and cardiac troponin T (cTnT) staining, and measuring lactate dehydrogenase (LDH) levels. In addition, various molecular and biochemical methods, as well as RNA sequencing were used to determine the effects and mechanism of action of vitamin B12 on I/R injury., Results: We found that high doses of vitamin B12 inhibited myocardial I/R injury. Furthermore, our data indicated that vitamin B12 supplementation alleviated cardiac dysfunction and injury by mitigating oxidative stress and apoptosis through downregulation of Nox2, the Ac-SOD2/SOD2 and Bax/Bcl-2 ratios and cleaved caspase-3 expression, and upregulation of SIRT3 expression and AMPK activity. However, these effects were largely reversed following treatment with the SIRT3 inhibitor, 3-TYP. Our RNA-sequencing data further demonstrated that vitamin B12 supplementation reduced inflammation during I/R injury., Conclusion: High doses of vitamin B12 supplements improved myocardial I/R injury by suppressing the accumulation of reactive oxygen species and apoptosis of myocardial tissue through modulation of the SIRT3/AMPK signaling pathway, while reducing inflammation. Our findings suggested that vitamin B12 administered at high doses could be a potential therapy for myocardial I/R damage., Competing Interests: Declaration of Competing Interest No conflict of interest, (Copyright © 2023 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Background: Pathogen infections seriously affect host health, and the use of antibiotics increases the risk of the emergence of drug-resistant bacteria and also increases environmental and health safety risks. Probiotics have received much attention for their excellent ability to prevent pathogen infections. Particularly, explaining mechanism of action of probiotics against pathogen infections is important for more efficient and rational use of probiotics and the maintenance of host health., Results: Here, we describe the impacts of probiotic on host resistance to pathogen infections. Our findings revealed that (I) the protective effect of oral supplementation with B. velezensis against Aeromonas hydrophila infection was dependent on gut microbiota, specially the anaerobic indigenous gut microbe Cetobacterium; (II) Cetobacterium was a sensor of health, especially for fish infected with pathogenic bacteria; (III) the genome resolved the ability of Cetobacterium somerae CS2105-BJ to synthesize vitamin B 12 de novo, while in vivo and in vitro metabolism assays also showed the ability of Cetobacterium somerae CS2105-BJ to produce vitamin B 12 ; (IV) the addition of vitamin B 12 significantly altered the gut redox status and the gut microbiome structure and function, and then improved the stability of the gut microbial ecological network, and enhanced the gut barrier tight junctions to prevent the pathogen infection., Conclusion: Collectively, this study found that the effect of probiotics in enhancing host resistance to pathogen infections depended on function of B 12 produced by an anaerobic indigenous gut microbe, Cetobacterium. Furthermore, as a gut microbial regulator, B 12 exhibited the ability to strengthen the interactions within gut microbiota and gut barrier tight junctions, thereby improving host resistance against pathogen infection. Video Abstract., (© 2023. The Author(s).)

Vitamin B12 plays a key role in DNA stability. Research indicates that vitamin B12 deficiency leads to indirect DNA damage, and vitamin B12 supplementation may reverse this effect. Vitamin B12 acts as a cofactor for enzymes such as methionine synthase and methylmalonyl-CoA mutase, which are involved in DNA methylation and nucleotide synthesis. These processes are essential for DNA replication and transcription, and any impairment can result in genetic instability. In addition, vitamin B12 has antioxidant properties that help protect DNA from damage caused by reactive oxygen species. This protection is achieved by scavenging free radicals and reducing oxidative stress. In addition to their protective functions, cobalamins can also generate DNA-damaging radicals in vitro that can be useful in scientific research. Research is also being conducted on the use of vitamin B12 in medicine as vectors for xenobiotics. In summary, vitamin B12 is an essential micronutrient that plays a vital role in DNA stability. It acts as a cofactor for enzymes involved in the synthesis of nucleotides, has antioxidant properties and has potential value as a generator of DNA-damaging radicals and drug transporters.

Vitamin B9 (folate)/B12 (cobalamin) deficiency is known to induce brain structural and/or functional retardations. In many countries, folate supplementation, targeting the most severe outcomes such as neural tube defects, is discontinued after the first trimester. However, adverse effects may occur after birth because of some mild misregulations. Various hormonal receptors were shown to be deregulated in brain tissue under these conditions. The glucocorticoid receptor (GR) is particularly sensitive to epigenetic regulation and post-translational modifications. In a mother-offspring rat model of vitamin B9/B12 deficiency, we investigated whether a prolonged folate supplementation could restore the GR signaling in the hypothalamus. Our data showed that a deficiency of folate and vitamin B12 during the in-utero and early postnatal periods was associated with reduced GR expression in the hypothalamus. We also described for the first time a novel post-translational modification of GR that impaired ligand binding and GR activation, leading to decrease expression of one of the GR targets in the hypothalamus, AgRP. Moreover, this brain-impaired GR signaling pathway was associated with behavioral perturbations during offspring growth. Importantly, perinatal and postnatal supplementation with folic acid helped restore GR mRNA levels and activity in hypothalamus cells and improved behavioral deficits.

Background: Hippocampus cells, responsible for learning and memory, are disturbed in Alzheimer's disease (AD), resulting in production of several inflammatory markers, such as neurexin 1 -neuroligin, cyclooxygenase-2 (COX-2), and caspase-3 proteins, used in measurement of AD's severity and development. Vitamin B 12 , which plays a role in brain functioning, has anti-inflammatory properties and its impairment is associated with apoptosis in Alzheimer's disease. This study aimed to investigate the effect of vitamin B 12 on restoration of Synaptic Plasticity on scopolamine-induced AD in rats., Methods: To simulate AD, Rats, except the control group were i.p. injected with 3 mg/kg scopolamine. Before scopolamine the pretreatment group vitamin B 12 (0.5, 2, and 4 mg/kg) was injected every day for the next 14 days. After 24 h, sectioning the rats' brains, the concentration of postsynaptic density protein 95 (PSD-95), neurexin 1-neurolgin, COX-2, and caspase-3 proteins in hippocampus were measured using immunoblotting., Results: B 12 significantly enhanced molecular balance. PSD-95 and neurexin 1 and neuroligin concentrations were significantly reduced, whereas COX-2 and activated caspase-3 were enhanced in the hippocampus of scopolamine-injected subjects. Their alterations were decreased after B12 administration., Conclusions: Vitamin B 12 protected scopolamine-injected rats and inhibited hippocampal inflammation and apoptosis and preserved pre- and post-synaptic proteins and possibly synaptic integrity in hippocampus route.

Objective: The human papilloma virus (HPV) is the etiological agent of cervical cancer in more than 95% of cases worldwide. Although most HPV infections clear up on their own and most pre-cancerous lesions spontaneously resolve, in some cases, they can persist, leading to lesions which may progress towards invasive cervical cancer., Materials and Methods: We evaluated the effects of the association of epigallocatechin gallate (EGCG) + folic acid (FA) + vitamin B12 (B12) + hyaluronic acid (HA) on HPV-positive cervical cancer cells (HeLa)., Results: The association of EGCG + FA + B12 + HA induced a significant increase of apoptosis and p53 gene expression with a concomitant decrease of E6/E7 gene expression, a marker of HPV infection., Conclusions: This study provides for the first-time evidence on the potential additive activity of EGCG + FA + B12 + HA in counteracting HPV infection, by increasing apoptosis and p53 expression in HPV-infected cervical HeLa cells.

The indiscriminate and rampant use of pesticides has raised serious concerns regarding their toxic impact on non-target organisms which underlines need for the development of an effective antidote. Metabolic activation of organophosphate pesticides by the phase I enzyme, cytochrome P450 plays a key role in influencing pesticide-toxicity. In this study, we have investigated the effect of environmentally relevant malathion concentration (100 μg/L) alone and in combination with vitamin B12 on the expression of genes related to xenobiotic metabolism such as CYP enzymes, PgP and the key oxidative stress responsive transcription factor, Nrf2 in zebra fish liver and brain. Expressions of Nrf2-trasncribed antioxidant genes and their activities were also measured. Administration of vitamin B12 successfully revived motor functions by modulation of AchE activity. Mechanistically, vitamin B12 was demonstrated to alleviate oxidative stress which was accompanied by decreased phase-I enzyme cyp3c1 and increased pgp expressions.

Objective: This study was aimed to systematically determine the effect of exercise combined with lysine-inositol vitamin B12 (VB12) therapy on the height of children with idiopathic short stature (ISS)., Methods: Sixty children with ISS were randomly divided into observation and control groups (N = 30). Each group was given lysine-inositol VB12 oral solution (10 mL bid). Simultaneously, the observation group exercised following the "ISS exercise instruction sheet". The height (H), growth velocity (GV), height standard deviation score (HtSDS) and other indicators were compared after 6 and 12 months of intervention, respectively. After 12 months of intervention, the biochemical indicators of the two groups, together with the correlation between the average days of exercise per week and average minutes of exercise per day, GV and serum growth hormone were analyzed., Results: After 6 and 12 months of treatment, the GV, serum GHRH, GHBP, GH, IGF-1, and IGFBP-3 levels in the observation group were significantly higher than those in the control group, and HtSDS was significantly lower than that in the control group (P<0.01). After 12 months of treatment, the height of the observation group was significantly higher than that of the control group (P<0.05). There was no significant difference in the biochemical indicators between two groups (P>0.05). Average days of exercise per week and average minutes of exercise per day were positively correlated with GV and GHBP levels. Serum GHRH, GH, IGF-1, and IGFBP-3 levels were negatively correlated. Average minutes of exercise per day were negatively correlated with GV and GHBP levels. Serum GHRH, GH, IGF-1, and IGFBP-3 levels were positively correlated., Conclusion: Regular and moderate stretching exercises combined with lysine-inositol VB12 can effectively promote height growth of children with ISS, which is clinically safe. The mechanism promotes serum GHRH, GHBP, GH, IGF-1, and IGFBP-3 levels., Competing Interests: Declaration of Competing Interest The authors declare that they have no conflicts of interest for this work., (Copyright © 2023. Published by Elsevier Ltd.)

COVID-19 induces chromatin remodeling in host immune cells, and it had previously been shown that vitamin B12 downregulates some inflammatory genes via methyl-dependent epigenetic mechanisms. In this work, whole blood cultures from moderate or severe COVID-19 patients were used to assess the potential of B12 as adjuvant drug. The vitamin normalized the expression of a panel of inflammatory genes still dysregulated in the leukocytes despite glucocorticoid therapy during hospitalization. B12 also increased the flux of the sulfur amino acid pathway, that regulates the bioavailability of methyl. Accordingly, B12-induced downregulation of CCL3 strongly and negatively correlated with the hypermethylation of CpGs in its regulatory regions. Transcriptome analysis revealed that B12 attenuates the effects of COVID-19 on most inflammation-related pathways affected by the disease. As far as we are aware, this is the first study to demonstrate that pharmacological modulation of epigenetic markings in leukocytes favorably regulates central components of COVID-19 physiopathology., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Cassiano, Cavalcante-Silva, Oliveira, Prado, Cardoso, Salim, Franco, D’Almeida, Francisco and Coimbra.)

Acetaminophen is a pharmaceutical synthesized non-opioid analgesic that belongs to the "aniline analgesics" class of medicine. Because it lacks a significant anti-inflammatory effect, it is not classified as a non-steroidal anti-inflammatory therapeutic medication (NSAID). As an over-the-counter pain reliever and antipyretic, Acetaminophen is the active metabolite of phenacetin and acetanilide, but it is less toxic than either precursor. According to some medical studies, Acetaminophen toxicity can be treated with vitamin B12. Acetaminophen-poisoned Male Wister rats were the subject model of the current study, which examines the effects of vitamin B12 on their hepatic health. There were three groups of animals: Acetaminophen treated animals (750 ml/kg), vitamin B12-treated animals (0.63 g/kg), and a control group that received distilled water (750 ml/kg). All animals were given oral medication for seven days. On the seventh day, the animal was sacrificed. Plasma levels of Alanine aminotransferase (ALT), Aspartate aminotransferase (AST), Glutathione (GSH), total antioxidant capacity (TAC), Caspase3, Malondialdehyde (MDA), Interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-) were measured in the cardiac blood samples. Vitamin B12 lowers liver enzyme levels in the blood, increases overall antioxidant levels, and compensates for tissue glutathione deficiency while lowering serum elevations. TNF-α and interleukin-6 levels are also reduced by caspase3. Acetaminophen-induced hepatic necrosis and inflammatory cell infiltration were both considerably reduced by vitamin B12 supplementation. According to this study, vitamin B12 was found to have a protective effect against acetaminophen-induced hepatotoxicity., Competing Interests: The authors declare that they have no conflict of interest.

There are growing evidence indicating that the adolescent brain is persistently affected by the use of psychostimulant agents. In this regard, alcohol drinking has become rather common among the adolescents in many societies during the last decade. It is currently well known that long-term ethanol exposure deteriorates various cognitive functions such as learning and memory. Mechanistically, these adverse effects have been shown to be mediated by oxidative damage to central nervous system. On the other hand, Vit-B12 is known to improve cognitive performance by suppression of oxidative parameters. Thus, in the present study we aimed to test whether treatment by Vit-B12 could prevent ethanol-induced complications in mice using behavioral and biochemical methods. Different groups of male Syrian mice received ethanol, ethanol+Vit-B12, Vit-B12 alone, or saline during adolescence and then learning and memory functions were assessed by Morris water maze (MWM) and Passive Avoidance (PA) tests. Finally, mice were sacrificed for measurement of biochemical factors. Results indicated that, adolescent ethanol intake impairs learning and memory function through exacerbation of oxidative stress and Vit-B12 treatment improves these complications by re-establishment of oxidant/anti-oxidant balance in CNS. Moreover, we found that Vit-B12 prevents ethanol-induced reduction of BDNF and enhancement of GFAP and acetylcholinesterase (AChE) activity. In conclusion, it seems that Vit-B12 supplementation could be used as an effective therapeutic strategy to prevent learning and memory defects induced by chronic alcohol intake during adolescence., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background: Vitamin B12 supplements typically contain doses that far exceed the recommended daily amount, and high exposures are generally considered safe. Competitive and syntrophic interactions for B12 exist between microbes in the gut. Yet, to what extent excessive levels contribute to the activities of the gut microbiota remains unclear. The objective of this study was to evaluate the effect of B12 on microbial ecology using a B12 supplemented mouse model with Citrobacter rodentium, a mouse-specific pathogen. Mice were fed a standard chow diet and received either water or water supplemented with B12 (cyanocobalamin: ~120 μg/day), which equates to approximately 25 mg in humans. Infection severity was determined by body weight, pathogen load, and histopathologic scoring. Host biomarkers of inflammation were assessed in the colon before and after the pathogen challenge., Results: Cyanocobalamin supplementation enhanced pathogen colonization at day 1 (P < 0.05) and day 3 (P < 0.01) postinfection. The impact of B12 on gut microbial communities, although minor, was distinct and attributed to the changes in the Lachnospiraceae populations and reduced alpha diversity. Cyanocobalamin treatment disrupted the activity of the low-abundance community members of the gut microbiota. It enhanced the amount of interleukin-12 p40 subunit protein (IL12/23p40; P < 0.001) and interleukin-17a (IL-17A; P < 0.05) in the colon of naïve mice. This immune phenotype was microbe dependent, and the response varied based on the baseline microbiota. The cecal metatranscriptome revealed that excessive cyanocobalamin decreased the expression of glucose utilizing genes by C. rodentium, a metabolic attribute previously associated with pathogen virulence., Conclusions: Oral vitamin B12 supplementation promoted C. rodentium colonization in mice by altering the activities of the Lachnospiraceae populations in the gut. A lower abundance of select Lachnospiraceae species correlated to higher p40 subunit levels, while the detection of Parasutterella exacerbated inflammatory markers in the colon of naïve mice. The B12-induced change in gut ecology enhanced the ability of C. rodentium colonization by impacting key microbe-host interactions that help with pathogen exclusion. This research provides insight into how B12 impacts the gut microbiota and highlights potential consequences of disrupting microbial B12 competition/sharing through over-supplementation. Video Abstract., (© 2023. The Author(s).)

Background: The rapid diagnostics of pathogens is essential to prescribe appropriate and early antibiotic therapy. The current methods for pathogen detection require the bacteria to grow in a culture medium, which is time-consuming. This increases the mortality rate and the global burden of antimicrobial resistance. Culture-free detection methods are still under development and are not used in the clinical routine. Therefore decreasing the culture time for accurate detection of infection and resistance is vital for diagnosis. Methods: In this study, we wanted to investigate easy-to-implement factors (in a minimal laboratory set-up), including inoculum size, incubation temperature, and additional supplementation ( e.g. , vitamin B12 and trace metals), that can significantly reduce the lag time (t lag ). These factors were arranged in simple two-level factorial designs using Gram-positive ( Escherichia coli and Pseudomonas aeruginosa ) and Gram-negative ( Staphylococcus aureus and Bacillus subtilis ) bacteria, including clinical isolates with known antimicrobial resistance profiles. Blood samples spiked with a clinical isolate of E. coli CCUG17620 were also tested to see the effect of elevated incubation temperature on bacterial growth in blood cultures. Results: We observed that increased incubation temperature (42°C) along with vitamin B12 supplementation significantly reduced the t lag (10 - 115 minutes or 4% - 49%) in pure clinical isolates and blood samples spiked with E. coli CCUG17620. In the case of the blood sample, PCR results also detected bacterial DNA after only 3h of incubation and at three times the CFU/mL. Conclusions: Enrichment of bacterial culture media with growth supplements such as vitamin B12 and increased incubation temperature can be a cheap and rapid method for the early detection of pathogens. This is a proof-of-concept study restricted to a few bacterial strains and growth conditions. In the future, the effect of other growth conditions and difficult-to-culture bacteria should be explored to shorten the lag phase., Competing Interests: No competing interests were disclosed., (Copyright: © 2023 Ali J et al.)

Silymarin has been used for improving hepatic damage and lipid disorders, but its action mechanism remains to be clarified. Here, we investigate the contributions of the gut microbiota to the improvement of liver lipid metabolism by silymarin. We find i) strong and significant microbial shifts upon silymarin but not silibinin treatment; ii) over 60% variations of liver fat are explained by silymarin-induced bacterial B12 production in male rats but not in male germ-free mice; iii) fecal microbiota transplantation confirms their protective roles against liver fat accumulation; iv) upregulation of one-carbon metabolism and fatty acid degradation pathways are observed based on the liver transcriptome analyses; and v) in humans the delta changes of serum B12 associate negatively with the fluctuations of serum triglycerides. Overall, we reveal a mechanism of action underpinning the lipid-lowering effect of silymarin via the gut microbiota and its vitamin B12 producing capabilities., (© 2023. The Author(s).)

Linagliptin is a dipeptidyl peptidase-4 (DPP-4) inhibitor used for the treatment of type 2 diabetes, with additional beneficial effects for the kidney. Treatment of mice with linagliptin revealed increased storage of cobalamin (Cbl, Vitamin B12) in organs if a standard Cbl diet (30 µg Cbl/kg chow) is given. In order to translate these findings to humans, we determined methylmalonic acid (MMA), a surrogate marker of functional Cbl homeostasis, in human plasma and urine samples (n = 1092) from baseline and end of trial (6 months after baseline) of the previously completed MARLINA-T2D clinical trial. We found that individuals with medium Cbl levels (MMA between 50 and 270 nmol/L for plasma, 0.4 and 3.5 µmol/mmol creatinine for urine, at baseline and end of trial) exhibited higher MMA values at the end of study in placebo compared with linagliptin. Linagliptin might inhibit the N-terminal degradation of the transcobalamin receptor CD320, which is necessary for uptake of Cbl into endothelial cells. Because we demonstrate that linagliptin led to increased organ levels of Cbl in mice, sustained constant medium MMA levels in humans, and inhibited CD320 processing by DPP-4 in-vitro, we speculate that linagliptin promotes intra-cellular uptake of Cbl by prolonging half-life of CD320., (© 2023. The Author(s).)

Background: Carbamazepine (CBZ) is widely used as an anti-epileptic drug. Vitamin B12 has been shown to protect against DNA damage caused by several mutagenic agents., Objective: This study aimed to investigate the effect of vitamin B12 on CBZ-induced genotoxicity in cultured human lymphocytes., Methods: Sister chromatid exchanges (SCEs) and chromosomal aberrations (CAs) genotoxic assays were utilized to achieve the study objective., Results: The results showed significantly higher frequencies of CAs and SCEs in the CBZ-treated cultures (12 μg/mL) compared to the control group (P<0.01). The genotoxic effects of CBZ were reduced by pre-treatment of cultures with vitamin B12 (13.5μg/ml, P<0.05). Neither CBZ nor vitamin B-12 showed any effects on mitotic and proliferative indices., Conclusion: CBZ is genotoxic to lymphocyte cells, and this genotoxicity can be reduced by vitamin B12., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

The compound 3-nitrooxypropanol (3-NOP) is a promising methane inhibitor, which performs well in inhibiting methane emission and does not affect animal feed intake and digestibility. However, it causes a significant increase in hydrogen production while suppressing methane emission, resulting in a waste of feed energy. Vitamin B 12 is a key factor in the propionate production pathway and thus plays an important role in regulating the hydrogen utilization pathway. In this study, the effects of 3-NOP combined with vitamin B 12 supplementation on rumen fermentation and microbial compositional structure in dairy cattle were investigated by simulating rumen fermentation in vitro. Experiments were performed using a 2 × 2-factorial design: two 3-NOP levels (0 or 2 mg/g dry matter) and 2 vitamin B 12 levels (0 or 2 mg/g dry matter). Three experiments were performed, each consisting of 4 treatments, 4 replicates, and 4 blanks containing only inoculum. The combined supplementation of 3-NOP and vitamin B 12 reduced methane emission by 12% without affecting dry matter digestibility. The combined addition of 3-NOP and vitamin B 12 significantly increased the concentration of propionate and reduced the concentration of acetate and the acetate to propionate ratio. At the bacterial level, 3-NOP increased the relative abundances of Christensenellaceae&#95;R-7&#95;group and Lachnospiraceae&#95;NK3A20&#95;group. Vitamin B 12 increased the relative abundances of unclassified&#95;f&#95;&#95;Prevotellaceae and Prevotellaceae&#95;UCG-003 and decreased the relative abundance of Lachnospiraceae&#95;NK3A20&#95;group. At the archaeal level, the combination of 3-NOP and vitamin B 12 increased the relative abundances of Methanobrevibacter&#95; sp.&#95; Abm4, OTU1125, and OTU95 and decreased the relative abundances of uncultured&#95;methanogenic&#95;archaeon&#95;g&#95;&#95;Methanobrevibacter, OTU1147, OTU1056, and OTU55. The results indicated that 3-NOP combined with vitamin B 12 could alleviate rumen hydrogen emission and enhance the inhibition of methane emission compared with 3-NOP alone., (The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)