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Protein kinases constitute essential regulatory components in the majority of cellular processes in eukaryotic cells. The CBL-INTERACTING PROTEIN KINASE (CIPK) family of plant protein kinases functions in calcium (Ca2+)-related signaling pathways and is therefore involved in the response to a wide variety of signals in plants. By covalently linking phosphate groups to their target proteins, CIPKs regulate the activity of downstream targets, their localization, their stability and their ability to interact with other proteins. In Arabidopsis, the CIPK23 kinase has emerged as a major hub driving root responses to diverse environmental stresses, including drought, salinity and nutrient imbalances, such as potassium, nitrate and iron deficiencies, as well as ammonium, magnesium and non-iron metal toxicities. This review will chiefly report on the prominent roles of CIPK23 in the regulation of plant nutrient transporters and on the underlying molecular mechanisms. We will also discuss the different scenarios explaining how a single promiscuous kinase, such as CIPK23, may convey specific responses to a myriad of signals.

Sulfate transporters (SULTRs) are an essential plant transporter class responsible for the absorption and distribution of sulfur, an essential plant growth element. SULTRs are also involved in processes related to growth and development and in response to environmental stimuli. In the present study, 22 TdSULTR family members were identified and characterized in the genome of Triticum turgidum L. ssp. durum (Desf.) using available bioinformatics tools. The expression levels of candidate TdSULTR genes were investigated under salt treatments of 150 and 250 mM NaCl after several different exposure times. TdSULTRs showed diversity in terms of physiochemical properties, gene structure, and pocket sites. TdSULTRs and their orthologues were classified into the known five main plant groups of highly diverse subfamilies. In addition, it was noted that segmental duplication events could lengthen TdSULTR family members under evolutionary processes. Based on pocket site analysis, the amino acids leucine (L), valine (V), and serine (S) were most often detected in TdSULTR protein binding sites. Moreover, it was predicted that TdSULTRs have a high potential to be targeted by phosphorylation modifications. According to promoter site analysis, the plant bioregulators ABA and MeJA were predicted to affect TdSULTR expression patterns. Real-time PCR analysis revealed TdSULTR genes are differentially expressed at 150 mM NaCl but show similar expression in response to 250 mM NaCl. TdSULTR reached a maximum level of expression 72 h after the 250 mM salt treatment. Overall, we conclude that TdSULTR genes are involved in the response to salinity in durum wheat. However, additional studies of functionality are needed to determine their precise function and linked-interaction pathways.

The small intestine is an important digestive organ and plays a vital role in the life of a pig. We tested the hypothesis that the length of the small intestine is related to growth performance and intestinal functions of piglets. A total of 60 piglets (Duroc × Landrace × Yorkshire), weaned at day 21, were fed an identical diet during a 28-day trial. At the end of the study, all piglets were sacrificed, dissected and grouped according to small intestine lengths (SILs), either short small intestine (SSI), middle small intestine (MSI) or long small intestine (LSI), respectively. Positive relationships between SIL and BW, average daily gain (ADG), average daily feed intake (ADFI) and gain-to-feed ratios (G : F) were observed. Final BW, ADG, ADFI and G : F significantly increased (P < 0.05) in MSI and LSI piglets compared with SSI piglets. Short small intestine and MSI had greater jejunal mucosa sucrase and alkaline phosphatase activities (P < 0.05) than LSI piglets. The mRNA level of solute carrier family 2 member 2 (Slc2a2) in the jejunal mucosa of SSI piglets was the greatest. The MSI piglets had a greater (P < 0.05) ileal villus height than other piglets and greater (P < 0.05) villus height-to-crypt depth ratios than LSI piglets. However, the LSI piglets had a greater (P < 0.05) ileal crypt depth than SSI piglets. No significant differences in duodenal, jejunal, caecal and colonic morphologies were detected among the groups. Moreover, luminal acetate, propionate, butyrate and total short-chain fatty acid contents were greater (P < 0.05) in SSI and MSI piglets than those in LSI piglets. In addition, there was greater serum glucose concentration in MSI piglets than other piglets. Serum albumin concentration in SSI piglets was the lowest. In conclusion, these results indicate that SIL was significantly positively associated with growth performance, and in terms of intestinal morphology and mucosal digestive enzyme activity, the piglets with a medium length of small intestine have better digestion and absorption properties.

There are over 420 human solute carrier (SLC) transporters from 65 families that are expressed ubiquitously in the body. The SLCs mediate the movement of ions, drugs, and metabolites across membranes and their dysfunction has been associated with a variety of diseases, such as diabetes, cancer, and central nervous system (CNS) disorders. Thus, SLCs are emerging as important targets for therapeutic intervention. Recent technological advances in experimental and computational biology allow better characterization of SLC pharmacology. Here we describe recent approaches to modulate SLC transporter function, with an emphasis on the use of computational approaches and computer-aided drug design (CADD) to study nutrient transporters. Finally, we discuss future perspectives in the rational design of SLC drugs.

Although prostacyclin (PGI2) has been well described as a regulator of smooth muscle activity, limited data are available concerning its role in the myometrium of pigs. The present research aimed to examine profiles of PGI2 synthase (PTGIS) and PGI2 receptor (PTGIR) expression and 6-keto PGF1α (a PGI2 metabolite) concentrations in the myometrium of gilts throughout the estrous cycle and during early pregnancy using qPCR, Western blot, and/or ELISA methods. Furthermore, myometrial explants were exposed to iloprost (a stable PGI2 analog) to investigate the effect of PGI2 on the mRNA expression of factors engaged in smooth muscle contraction, nutrient transport, prostaglandin synthesis and action, and inflammatory response. PTGIS mRNA expression was greater in cyclic than in pregnant gilts on days 11–12 after estrus and was accompanied by greater concentrations of 6-keto PGF1α detected in cyclic than in pregnant animals on days 11–20. Iloprost stimulated fatty acid transporters and contractility-related calponin 1 and caldesmon 1 mRNA expression and decreased interleukin 1β and tumor necrosis factor transcript abundance. The obtained results indicate a physiologically relevant role of PGI2 during the estrous cycle in the porcine myometrium with its importance for regulating the expression of contractility-, nutrient transport- and inflammatory response-related factors.

INTRODUCTION As an exogenous food contaminant, dietary oxidized lipid impairs growth and development, and triggers chronic diseases in humans or animals. This study explores the effects of soybean oil with different oxidative degree on the placental injury of gestational rats. METHODS AND RESULTS Thirty-two female adult rats are randomly assigned to four groups. The control group is fed the purified diet with fresh soybean oil (FSO), and the treatment groups are fed purified diets with lipid content replaced by oxidized soybean oil (OSO) at 200, 400, and 800 mEqO2 kg-1 from conception until delivery. On day 20 of gestation, OSO decreased placental and embryonic weights as the oxidative degree increased linearly and quadratically. The expression of Bax showed a linear increase, and Bcl-2 decreased as the oxidative degree increased. The expression of Fosl1 and Esx1 is linearly and quadratically decreased in OSO-treated groups than FSO group. OSO decreased the level of IL-10 but increased expression of IL-1β in placenta and plasma. OSO remarkably upregulates levels of Fatp1 and Glut1 and decreases expression of Snat2 and Glut3. CONCLUSION OSO aggravates placental injury by modulating nutrient transporters and apoptosis-related genes, impedes placental growth and development, and ultimately leads to the decrease of fetal weight.

Solute and ion transporters are proteins essential for cell nutrition, detoxification, signaling, homeostasis and drug resistance. Being polytopic transmembrane proteins, they are co-translationally inserted and folded into the endoplasmic reticulum (ER) of eukaryotic cells and subsequently sorted to their final membrane destination via vesicular secretion. During their trafficking and in response to physiological/stress signals or prolonged activity, transporters undergo multiple quality control processes and regulated turnover. Consequently, transporters interact dynamically and transiently with multiple proteins. To further dissect the trafficking and turnover mechanisms underlying transporter subcellular biology, we herein describe a novel mass spectrometry-based proteomic protocol adapted to conditions allowing for maximal identification of proteins related to N source uptake in A. nidulans. Our analysis led to identification of 5690 proteins, which to our knowledge constitutes the largest protein dataset identified by omics-based approaches in Aspergilli. Importantly, we detected possibly all major proteins involved in basic cellular functions, giving particular emphasis to factors essential for membrane cargo trafficking and turnover. Our protocol is easily reproducible and highly efficient for unearthing the full A. nidulans proteome. The protein list delivered herein will form the basis for downstream systematic approaches and identification of protein–protein interactions in living fungal cells.

Nitrogen (N), phosphorus (P), and potassium (K) are three major macronutrients essential for plant life. These nutrients are acquired and transported by several large families of transporters expressed in plant roots. However, it remains largely unknown how these transporters are distributed in different cell-types that work together to transfer the nutrients from the soil to different layers of root cells and eventually reach vasculature for massive flow. Using the single cell transcriptomics data from Arabidopsis roots, we profiled the transcriptional patterns of putative nutrient transporters in different root cell-types. Such analyses identified a number of uncharacterized NPK transporters expressed in the root epidermis to mediate NPK uptake and distribution to the adjacent cells. Some transport genes showed cortex- and endodermis-specific expression to direct the nutrient flow toward the vasculature. For long-distance transport, a variety of transporters were shown to express and potentially function in the xylem and phloem. In the context of subcellular distribution of mineral nutrients, the NPK transporters at subcellular compartments were often found to show ubiquitous expression patterns, which suggests function in house-keeping processes. Overall, these single cell transcriptomic analyses provide working models of nutrient transport from the epidermis across the cortex to the vasculature, which can be further tested experimentally in the future.

Drought stress is one of the major abiotic factors affecting the growth and development of crops. The primary effect of drought is the alteration of water and nutrient uptake and transport by roots, related essentially with aquaporins and ion transporters of the plasma membrane. Therefore, the efficiency of water and nutrient transport across cell layers is a main factor in tolerance mechanisms. The regulation of this transport under water stress - in relation to the differing degrees of tolerance of crops and the effect of arbuscular mycorrhizae, together with signaling mechanisms - is reviewed here. Three different phases in the response to stress (immediate, short-term and long-term), involving different signals and levels of gene regulation, are highlighted.

This study was conducted to examine the effects of dietary taurine supplementation on productive performance, nutrient digestibility, antioxidant status, and the gene expression of ileal nutrient transporters in laying quails reared under heat stress (HS). One hundred and eighty laying Japanese quails (Coturnix coturnix japonica) were fed a basal diet or basal diet supplemented with either 2.5 or 5 g of taurine per kg of diet, and reared at either 22 ± 2 °C for 24 h/d (thermoneutral, TN) or 34 ± 2 °C for 8 h/d (HS) for 12 weeks. The quails reared under HS consumed less feed, produced less egg, and had lower dry matter, organic matter and crude protein apparent digestibilities compared with the quails reared under the TN condition (P = 0.001). However, increasing taurine concentrations in the diet improved feed intake and egg production (P = 0.001), but also the apparent digestibilities (P ≤ 0.027) in quails reared under HS. The greater doses (5 g/kg) of taurine resulted in more responses. The quails reared under HS had greater serum and liver MDA concentrations (P = 0.0001) which decreased with dietary taurine supplementations, particularly greater doses. The gene expressions of ileal PEPT1, EAAT3, CAT1, CAT2, SGLT1, SGLT5, GLUT2, and GLUT5 decreased under HS conditions (P = 0.001). However, supplementing taurine, in a dose-dependent fashion, to the diet of quails reared under HS resulted in increases in the gene expressions of the transporters (P 0.05) except for CAT1. The results of the present work showed that taurine supplementation, particularly with greater doses (5 g/kg), to the diet of laying quails kept under HS acts as alleviating negative effects of HS, resulting in improvements in productive performance and nutrient digestion, and also upregulation of ileal nutrient transporters.

Fayoumi chickens are believed to be more disease resistant compared to commercial broiler chickens. The objective of this study was to compare mRNA expression of intestinal nutrient transporters, digestive enzymes, and host defense peptides (HDP) between Eimeria maxima-challenged Fayoumi and Ross broiler chickens. At 21 d of age, Ross broilers and Fayoumi lines M5.1 and M15.2 were challenged with 1,000 E. maxima oocysts. Control birds were not challenged. Duodenum, jejunum, and ileum were sampled (n = 6) at 7 d post challenge. Gene expression was analyzed using relative quantification PCR. Data were analyzed by ANOVA and significance level was set at P< 0.05. There was numerical, but not statistically significant, differential weight gain depression for Ross (15%) and Fayoumi lines M5.1 (21%) and M15.2 (22%) and significant line-specific changes in gene expression. For nutrient transporters, there was downregulation of mRNA for the brush border membrane, amino acid transporters b(0,+) AT/rBAT, BoAT, and EAAT3 in different segments of the small intes-tine of Ross and both lines of Fayoumi chickens, indicating that E. maxima challenge likely caused a decrease in nutrient uptake. For HDP, there was downregulation of avian beta defensin (AvBD) 1, 6, 10, 12, and 13 mRNA in the jejunum of the 2 Fayoumi lines, but no change in the Ross broilers. In the duodenum, there was upregulation of AvBD10 mRNA in the Ross and both Fayoumi lines and additionally upregulation of AvBD11, 12, and 13 mRNA in only Fayoumi line M15.2. Liver expressed antimicrobial peptide 2 (LEAP2) mRNA was downregulated in the duodenum and jejunum of Ross and Fayoumi line M5.1 but not in Fayoumi line M15.2. The homeostatic, non-challenged levels of AvBD mRNA were greater in Fayoumi line M15.2 than Ross and Fayoumi line M5.1 in the duodenum and ileum. This study demonstrates tissueand genetic line-specific transcriptional responses to E. maxima, highlights novel potential candidate genes for response to coccidiosis, and confirms a role for several previously reported genes in response to coccidiosis. College of Agriculture and Life Sciences Pratt Endowment at Virginia Tech; Virginia Agricultural Experiment Station; Hatch Program of the National Institute of Food and Agriculture, U.S. Department of Agriculture; Animal Health Formula Funds; Hatch project, Iowa State University [5458] This work was funded in part by the College of Agriculture and Life Sciences Pratt Endowment at Virginia Tech (SS), the Virginia Agricultural Experiment Station and the Hatch Program of the National Institute of Food and Agriculture, U.S. Department of Agriculture (EAW), and Animal Health Formula Funds and Hatch project number 5458, Iowa State University (SJL). Public domain – authored by a U.S. government employee

Purpose of review The current review provides an overview of recent literature on new findings related to bariatric surgery and gut gene expression. Recent findings Bariatric surgery modulates the expression of intestinal genes. Experimental and clinical investigations have demonstrated the association of gut rearrangement with changes in intestinal expression of genes related to glucose metabolism. Recent data suggest that bariatric surgery also affects expression of genes belonging to other pathways, including nutrient transporters and metabolism of vitamin B12, decreasing pathway-encoding genes that may contribute to vitamin B12 deficiency in the postoperative period. Summary Bariatric surgery is an effective intervention strategy against severe obesity, resulting in sustained weight loss and reduction of comorbidities. Nutritional genomic changes appear in response to bariatric surgery, possibly due to adaptive gut response. Improved understanding of the molecular pathways modulated by this intervention may facilitate weight and comorbidities management.

Background Our previous study suggested that short-term lysine restriction improved feed intake and gut microbiota in piglets. Thus, in this study, we further used proteomics technology to investigate the potential mechanism associated with long-term lysine restriction in pigs. In addition, blood biochemical parameters, meat quality, and muscle nutrient transporters were also evaluated in lysine restricted pigs. Results The results showed that 131 proteins in the liver were markedly altered in response to dietary lysine restriction, with 54 being downregulated and 77 being upregulated, which mainly involved in neurodegenerative diseases, oxidative phosphorylation, and metabolic pathways. In addition, lysine restriction markedly reduced serum BUN, CHOL, and HDL abundances. Dietary lysine restriction enhanced meat color lightness and upregulated SLC7A2 expression. Conclusion Lysine restriction affected meat quality, blood biochemical parameters, and liver global protein expressions. This study is the first attempt to evaluate the liver protein profile of lysine restricted pigs, and the current results may provide valuable information with respect to better understanding the host response to lysine restriction in pigs.

The objective of this study was to investigate the effect of a wheat-based diet, exhibiting different levels of mycotoxin contamination and the presence of a mycotoxin binder on growth performance, nutrient digestibility and digestive health in finisher pigs. Sixty-four pigs (38.7 kg (SD 3.48 kg)) were assigned to one of four dietary treatments: (T1) low quality wheat diet, (T2) low quality wheat diet containing 2 g/kg of a mycotoxin binder, (T3) high quality wheat diet, (T4) high quality wheat diet containing 2 g/kg of a mycotoxin binder. The inclusion of wheat was 500 g/kg. The mycotoxin binder used was a Hydrated Sodium-Calcium-Aluminum-Silicate, which also included calcium propionate and calcium formate. The low quality wheat grain had a higher level of zearalenone (233.02 vs. 33.36 μg/kg), aflatoxin (4.08 vs. 2.94 μg/kg) and ochratoxin (28.20 vs. 4.23 μg/kg). Pigs offered the low quality wheat diet had a lower average daily gain (ADG) (P < 0.05), average daily feed intake (ADFI) (P < 0.001) and had a reduced coefficient of apparent total tract digestibility (CATTD) (P < 0.05) of nitrogen (N) and gross energy (GE) compared with pigs offered the high quality wheat diets. The inclusion of a mycotoxin binder improved ADG and ADFI (P < 0.05) and also increased the CATTD of N and GE compared to diets without a mycotoxin binder. Pigs offered the low quality wheat diets had increased (P < 0.05) expression of tumour necrosis factor (TNF) in the duodenum and colon and of claudin 2 (CLDN2) (P < 0.001) in the duodenum, compared to pigs offered the high quality wheat diets. Pigs offered diets containing a mycotoxin binder had increased expression of ghrelin (GHRL) (P < 0.05) in the duodenum compared to pigs offered diets without a mycotoxin binder. There was a wheat × mycotoxin binder interaction on the expression of peptide transporter 1 gene (SLC15A1/PEPT1) and sodium-glucose linked transporter 1 gene (SLC5A1/SGLT1) (P < 0.05) in the duodenum. Pigs offered the low quality wheat with a mycotoxin binder had lower expression of SLC15A1/PEPT1 and SLC5A1/SGLT1 expression compared to the low quality wheat diet only. However, there was no response to mycotoxin binder supplementation with the high quality wheat diet. In conclusion, the low quality wheat reduced ADG, ADFI, nutrient digestibility and modified the gene expression of genes involved in intestinal nutrient transport and inflammation. The supplementation of a mycotoxin binder improved ADG, ADFI, nutrient digestibility and also improved digestive health through increases in nutrient transporter and tight junction gene expression. Department of Agriculture, Food and the Marine Department of Agriculture Food and the Marine Research Stimulus Fund; 11/S/122: Feed Evaluation for Accurate Nutrition

MicroRNAs (miRNAs), a group of small-RNA regulators, control diverse developmental processes and stress responses. Recent studies of nutrient-responsive miRNAs have offered novel insights into how plants regulate gene expression to coordinate endogenous demand and external availability of nutrients. Here, we review the mechanisms mediated by miRNAs to facilitate nutrient transport and utilization and show that miRNAs: first, control nutrient uptake and translocation by targeting nutrient transporters or their regulators; second, adjust nutrient metabolism by redistributing nutrients for biosynthesis of more essential compounds; and third, modulate root development and microbial symbiosis to exploit soil nutrients. We also highlight the long-distance movement of miRNAs in maintaining whole-plant nutrient homeostasis and propose several directions for future research.

Intestinal villi are important structures for digesting and absorbing nutrients. It was hypothesized that intestinal villous height (VH) is related to growth performance, and that VH is associated with digestive and absorptive capabilities in piglets. Sixty 21-d-old weaned piglets were fed identical diets for 28 days. The piglets were grouped according to jejunal or ileal VH at the end of the experiment, including short, middle and high VH groups. The final BW (quadratic, p = .003), ADG (liner, p = .052; quadratic, p = .030) and G: F (liner, p = .074; quadratic, p = .005) were greater in higher VH piglets compared with the shorter VH piglets. Significant linear relationships were recorded between jejunal VH and maltase (linear, p = .003) and sucrase (linear, p = .004) activities. Besides, jejunal VH was significantly associated with maltase (r = 0.357, p = .007), sucrase (r = 0.394, p = .003) and alkaline phosphate (r = 0.288, p = .033) activities. Jejunal Slc1a1 (linear, p = .004) mRNA expression increased as VH increased, while Slc7a1 (linear, p = .007) expression decreased as VH increased, and Slc1a1 (r = 0.292, p = .031) expression was positively related to VH. In the ileum, Slc5a1 (linear, p = .002) and Slc1a1 (linear, p < .001) expression increased as VH increased, whereas Slc7a1 (linear, p = .045) expression decreased as VH increased. A positive relationship between ileal VH and Slc5a1 (r = 0.331, p = .018), Slc1a1 (r = 0.444, p = .001) and Slc6a19 (r = 0.314, p = .026), respectively, was established. Additionally, Slc7a9 (r = 0.0271, p = .057) expression tended to be positively associated with VH in ileum. In conclusion, the growth performance of piglets increased with increasing VH, which may via affecting mucosal enzymes activities and nutrient transporters' mRNA expression.

Two experiments were conducted to (1) investigate the effects of different doses of dihydroartemisinin (DiHA) on growth performance, nutrient digestibility, serum biochemistry, antioxidant and immune function in weaned piglets and determine the optimal dose of DiHA and (2) investigate the effects of DiHA on growth, intestinal digestive function and nutrient transporters in weaned piglets with intrauterine growth retardation (IUGR). In experiment 1, a total of 360 21-day-old weaned piglets were randomly allocated into six dietary treatments, including control group (basal diet), DiHA 20, DiHA 40, DiHA 80, DiHA 160 and DiHA 320 groups (basal diet supplemented with 20, 40, 80, 160, 320 mg/kg DiHA, respectively). At 42 days of age, a digestibility trial was conducted for 7 days. At 49 days of age, the growth performance, serum biochemistry, antioxidant and immune function were measured. The results showed that DiHA at the dose of 80 mg/kg significantly improved (P

The objective of this experiment was to determine the effects of a phytogenic feed additive on turkey poult performance over a 6-week brooding period. A total of 864 male Hybrid Converter turkey poults were placed into pens that were randomly assigned one of three experimental groups. The three experimental diets included a corn-soy diet with no additives (PC), a similar diet with a 1.5 % reduction in crude protein and key amino acids (NC), and the same NC diet with Digestarom® (PFA) included at a rate of 1 g/kg. Performance-based experimental units (EU) consisted of one pen of 24 poults, with 12 EU per treatment. Mortality were recorded daily, and feed intake (FI), mortality corrected feed efficiency (FE), and body weight gain (BWG) were determined on days 14, 28, and 42. Samples were taken on days 28 and 42 to determine the coefficient of apparent crude protein digestibility (CPD). The expression of genes was determined for selected enzymes and nutrient transporters. The PFA improved poult BWG beyond that of the PC and NC on day 14 (263.7 vs. 252.5 and 252.7 g/bird, respectively; P ≤ 0.05), and there were no differences in FE (P > 0.05). On day 28, BWG was similar among treatments, although the PC had the highest FE (P

Porcine reproductive and respiratory syndrome (PRRSV) and porcine epidemic diarrhea (PEDV) viruses are two of the most economically significant diseases to affect the U.S. swine industry today. Yet, little is known about how they impact pig nutrient digestibility, intestinal function and feed efficiency. Therefore, the overall objective of this thesis was to determine the impact of PRRSV and PEDV viruses, alone or in combination, on grower pig performance, tissue accretion and on intestinal function and integrity. To accomplish these objectives, a series of experiments were conducted and are outlined in three research chapters (Chapter 2, 3 and 4). In Chapter 2, an experiment was conducted using growing pigs to assess the longitudinal impact of PRRSV on growth performance, feed efficiency, tissue accretion and apparent total tract digestibility (ATTD). In Chapter 3 pigs were infected with PRRSV, PEDV or a combination of both, to determine their impact on growth performance, feed efficiency, ATTD and apparent ileal digestibility (AID). The final research chapter (Chapter 4) assessed the effects of PRRS and PED viruses on intestinal integrity and function. The results from this research indicate that PRRSV significantly reduces overall growth performance and feed efficiency. It also reduces ATTD of nutrients and energy in an industry setting (Chapter 2), but did not reduce AID of nutrients (Chapter 3). Expectedly, PRRSV infection did not affect markers of intestinal health and integrity, but did improve active glucose and lysine transport in the jejunum (Chapter 4). Jejunum sucrase activity was also improved during the 21 day PRRSV infection. However, no differences in the gene abundance of nutrient transporters between PRRSV and healthy

In the present study, we investigated the effects of chromium-picolinate (CrPic) and chromium-histidinate (CrHis) on nutrient digestibility and nutrient transporters in laying hens exposed to heat stress (HS). Hens (n = 1800; 16 weeks old) were kept in cages in temperature-controlled rooms at either 22 ± 2 °C for 24 h/day (thermoneutral (TN)) or 34 ± 2 °C for 8 h/day, from 08:00 to 17:00, followed by 22 °C for 16 h (HS) for 12 weeks. Hens reared under both environmental conditions were fed one of three diets: a basal diet and the basal diet supplemented with either 1.600 mg of CrPic (12.43% Cr) or 0.788 mg of CrHis (25.22% Cr) per kg of diet, delivering 200 μg elemental Cr per kg of diet. HS impaired the nutrient digestibility and nutrient transports in laying hens (P

Salmonella and Campylobacter are the leading causes of bacterial foodborne illness in the United States. Commonly found in the gastrointestinal tract of poultry, Salmonella and Campylobacter may show little to no signs of infection in birds. The objective of this dissertation was to evaluate the influence on mRNA abundance of nutrient transporters and host defense peptides (HDPs) during a Salmonella or a Campylobacter challenge in young commercial broilers. Comparisons were made between non-challenged and challenged (106, 107, or 108 colony forming units of Salmonella or Campylobacter) broilers on expression of nutrient transporters and host defense peptides in the duodenum, jejunum, ileum and cecum at various days after inoculation. During a Salmonella challenge, changes in mRNA abundance of nutrient transporters and avian beta-defensins (AvBD) vary by day, tissue and challenge dose. ZnT1 may play an important role during a Salmonella challenge as mRNA abundance of ZnT1 significantly increased (P

How do sessile plants cope with irregularities in soil nutrient availability? The uptake of essential minerals from the soil influences plant growth and development. However, most environments do not provide sufficient nutrients; rather nutrient distribution in the soil can be uneven and change temporally according to environmental factors. To maintain mineral nutrient homeostasis in their tissues, plants have evolved sophisticated systems for coping with spatial and temporal variability in soil nutrient concentrations. Among these are mechanisms for modulating root system architecture in response to nutrient availability. This review discusses recent advances in knowledge of the two important strategies for optimizing nutrient uptake and translocation in plants: root architecture modification and transporter expression control in response to nutrient availability. Recent studies have determined (i) nutrient-specific root patterns; (ii) their physiological consequences; and (iii) the molecular mechanisms underlying these modulation systems that operate to facilitate efficient nutrient acquisition. Another mechanism employed by plants in nutrient-heterogeneous soils involves modification of nutrient transport activities in a nutrient concentration-dependent manner. In recent years, considerable progress has been made in characterizing the diverse functions of transporters for specific nutrients; it is now clear that the expression and activities of nutrient transporters are finely regulated in multiple steps at both the transcriptional and post-transcriptional levels for adaptation to a wide range of nutrient conditions.

This paper presents a methodology for identifying the kinetic parameters of a biological system and their relationships with the concentration variations of the species by means of in silico experiments. A nonlinear goal programming technique is employed to identify the kinetic parameters that best satisfy the biological hypothesis of the system behaviour. The simulations are performed on a stochastic simulator for the Calculus of Wrapped Compartments. The extraction of parameters with optimization techniques is usually applied to systems modeled by means of differential equations. Its application in a stochastic framework is rather new. The methodology may open a new path for the investigation of a broader class of biochemical systems (including those that cannot be easily modeled by differential equations) when in vitro experimental measurements are unavailable. The methodology is applied to model the nutrient exchanges in arbuscular mycorrhiza, the most wide-spread plant/fungus symbiosis focusing in particular to a newly discovered ammonium transporter: LjAMT2;2. This case study of ammonia and phosphate plant uptake from the fungus has been dissected in known and hypothetical mechanisms. The results of the analysis provide setting of recent experimental results of carrier LjAMT2;2 and support new insights into biological hypotheses to be put in place.

Nutrient transporters play significant roles in physiological hormonal and cellular functions as well as in the maintenance of nutrient metabolism. Lifestyle-related disease can be defined as caused by a disturbance in nutrient metabolism as found in diabetes, dyslipidemia, arteriosclerosis, etc. Therefore, deterioration of nutrient transporters by a genetic mutation or abnormal regulation would cause various lifestyle-related diseases. For instance, dysregulation of muscular glucose transport causes hyperglycemia, and impairment of pancreatic glucose transport can be related to inadequate insulin secretion. These deleterious changes in glucose transport can be a cause of diabetes mellitus. Here, we introduce some examples that indicate the relationship between impairment of nutrient transporters and development of lifestyle-related diseases.

The objective of this study was to determine the effect of phytase supplementation and coccidial vaccine challenge (CVC) on jejunal and ileal nutrient and energy digestibility and the expression of genes of some markers of inflammation and nutrient transporters in broilers. Ross 708 broilers (384 males) were randomly assigned to six treatments in a factorial arrangement with two levels of CVC (0× or 25×) and three levels of phytase [0, 1000, or 5000 phytase units (FTU) kg−1 diet] with eight birds per pen and eight replicates per treatment. On day 42 post hatching, 192 birds received no challenge (NCH) or challenged (CHA) with 25× coccidial vaccine. Birds received the experimental diets from day 49 post hatching until day 55. Jejunal dry matter and energy digestibility decreased (P

Drug delivery to the brain is made difficult by the blood-brain barrier (BBB) which is selectively permeable to organic drug compounds. Several membrane solute and nutrient transporters are expressed in the BBB vasculature, which may be utilized as mechanism of delivery of drugs to the brain. Of interest to us, are the organic cation transporters which could be used to transport cationic compounds into the CNS. In this mini-review, we will review the current understanding of the structural requirements for designing compounds which could effectively use organic cation transporters (OCT). For the first time, structural requirements for both OCT1 and OCT2 versus the BBB choline transporter (BBBCHT) are discussed and compared. The information gained here could increase the success rate in successful CNS drug delivery and therapeutics.

The blood–brain barrier (BBB) is a major physiological barrier for drugs that target CNS receptors or enzymes. Several methods exist by which permeability to the CNS can be increased, one of which is using native nutrient transporters to carry these drugs through the endothelial cells of the BBB. In this review, we focus on work that characterizes the use of nutrient transporters of the BBB in delivering drugs to the CNS.

Colicins are folded protein toxins that face the formidable task of translocating across one or both of the Escherichia coli cell membranes in order to induce cell death. This translocation is achieved by parasitizing host proteins. There has been much recent progress in our understanding of the early stages of colicin entry, including the binding of outer-membrane nutrient transporters and porins and the subsequent recruitment of periplasmic and inner-membrane proteins that, together, trigger translocation. As well as providing insights into how these toxins enter cells, these studies have highlighted some surprising similarities in the modes of action of the systems that colicins subvert.

The chicken small intestine undergoes structural and functional changes during the early posthatch period to accommodate the transition from a lipid-rich diet inside the egg to a carbohydrate- and protein-based diet. Many of the enterocyte brush-border membrane-associated proteins responsible for mediating changes in nutrient utilization are unknown. The objective of this study was to conduct a proteomic analysis of chicken small intestine during the early posthatch period. We isolated brush-border membrane at day of hatch and days 1, 3, 7, and 14 posthatch from the small intestine of 2 genetic lines of broilers that differ in growth performance, and performed 2D gel-electrophoresis. A total of 1693 spots were analyzed by matrix-assisted laser desorption/ionization-tandem time-of-flight mass spectrometry (MALDI-TOF/TOF). In total, 132 different proteins were identified and grouped according to biological function. Of these, there were 10 nutrient transporters, 9 digestive enzymes, and 17 proteins associated with cytoskeletal structure and microvilli organization. The remaining proteins were classified as basolateral membrane (3), endosomal/membrane trafficking (8), signaling (14), metabolic (33), degradative (5), stress-related (5), protein synthesis machinery/mitochondria/nucleus (19), immunologic (1), or unknown (8). Of the spots in which proteins were identified, there were 10 that showed an effect of broiler genetic line on protein spot density (P0.001) and 19 spots showing a correlation of broiler genetic line x age (P0.001). Identification of brush-border membrane-associated proteins is an important step in furthering our understanding of digestion and absorption in the chicken.

In recent years, researchers have given emphasis on the differences in physiological parameters between early and late hatched chicks within a hatch window. Considering the importance of intestine development in newly hatched chicks, however, changes in gene expression of nutrient transporters in the jejunum of early hatched chicks within a hatch window have not been studied yet. This study was conducted to determine the effects of egg storage duration before incubation and hatch window on intestinal development and expression of PepT1 (H+-dependent peptide transporter) and SGLT1 (sodium glucose co-transporter) genes in the jejunum of early hatched broiler chicks within a 30 h of hatch window. A total of 1218 eggs obtained from 38-week-old Ross 308 broiler breeder flocks were stored for 3 (ES3) or 14 days (ES14) and incubated at the same conditions. Eggs were checked between 475 and 480 h of incubation and 40 chicks from each egg storage duration were weighed; chick length and rectal temperature were measured. The chicks were sampled to evaluate morphological parameters and PepT1 and SGLT1 expression. The remaining chicks that hatched between 475 and 480 h were placed back in the incubator and the same measurements were conducted with those chicks at the end of hatch window at 510 h of incubation. Chick length, chick dry matter content, rectal temperature and weight of small intestine segments increased, whereas chick weight decreased during the hatch window. The increase in the jejunum length and villus width and area during the hatch window were higher for ES3 than ES14 chicks. PepT1 expression was higher for ES3 chicks compared with ES14. There was a 10.2 and 17.6-fold increase in PepT1 and SGLT1 expression of ES3 chicks at the end of hatch window, whereas it was only 2.3 and 3.3-fold, respectively, for ES14 chicks. These results suggested that egg storage duration affected development of early hatched chicks during 30 h of hatch window. It can be concluded that the ES14 chicks would be less efficiently adapted to absorption process for carbohydrates and protein than those from ES3 at the end of the hatch window.

Diseases caused by pathogenic trypanosomatids cause great suffering throughout the developing world. New drugs for these diseases are urgently needed. Recent technological advances have permitted the identification and validation of numerous drug targets in these organisms. However, efforts to develop inhibitors of these targets, that may then be taken forward for development into new drugs, have been comparatively scarce. In this review we discuss the design, synthesis and evaluation of inhibitors of two drug targets in trypanosomatids, 6-phosphogluconate dehydrogenase, the third enzyme of the pentose phosphate pathway, and dihydrofolate reductase, a key enzyme involved in DNA synthesis. Enzyme inhibitors can only be useful as drugs if they can enter cells and bind to their targets. Therefore we also discuss approaches to designing molecules that can specifically cross the plasma membrane of African trypanosomes via unusual nutrient transporters.

Biotrophic interfaces are formed in mutualistic and parasitic plant–fungus interactions. They result from coordinated developmental programs in both partners and represent specialized platforms for the exchange of information and nutritional metabolites. New data on the establishment and the components of functional interfaces have been obtained in a number of ways. First, by isolation of symbiotically defective mutants; second, by characterization of new genes and their products; and, third, by the identification and localization of components of biotrophic interfaces, such as cell-wall proteins, H + -ATPases and nutrient transporters.

Do animal species that normally consume large meals at long intervals evolve to down-regulate their metabolic physiology while fasting and to up-regulate it steeply on feeding? To test this hypothesis, we compared postfeeding regulatory responses in eight snake species: four frequent feeders on small meals and four infrequent feeders on large meals. For each species, we measured factorial changes in metabolic rate, in activities and capacities of five small intestinal brush border nutrient transporters, and in masses of eight organs that function in nutrient processing after consumption of a rodent meal equivalent to 25% of the snake's body mass. It turned out that, compared with frequent feeders, infrequent feeders digest that meal more slowly; have lower metabolic rates, organ masses, and nutrient uptake rates and capacities while fasting; have higher energy expenditure during digestion; and have higher postfeeding factorial increases in metabolic rate, organ masses, and nutrient uptake rates and capacities. These conclusions, which conform to the hypothesis mentioned above, remain after phylogeny has been taken into account. The small organ masses and low nutrient transporter activities during fasting contribute to the low fasting metabolism of infrequent feeders. Quantitative calculations of partial energy budgets suggest that energy savings drive the evolution of low mass and activities of organs during fasting and of large postfeeding regulatory responses in infrequent feeders. We propose further tests of this hypothesis among other snake species and among other ectotherms.

The main nutritional role of the placenta is to provide the correct mix of nutrients in sufficient quantities to support fetal growth and development throughout pregnancy while coping with wide variations in maternal nutrient intake between pregnancies and temporal variations within a pregnancy. The placenta represents a nutritional ‘bottleneck’ where competition for nutrient transporters and metabolic selectivity, acting in concert with maternal adaptations, allows the placenta to regulate the nutrient mix within the fetal circulation. The fetus itself also plays an active role in regulating key aspects of placental transport in order to meet its own nutrient requirements.

Chick embryos derive nutrients from the yolk during incubation and transition to intestinal absorption posthatch. Nutrient uptake is mediated by digestive enzymes and membrane bound transporter proteins. The objective of this study was to determine expression profiles of nutrient transporters and digestive enzymes during incubation in the yolk sac membrane (YSM) and small intestine of Leghorn and Cobb chickens derived from 22–30 wk (young) and 45–50 wk (old) breeder flocks. Genes examined included peptide transporter PepT1, amino acid transporters EAAT3, CAT1, and B0AT, monosaccharide transporters SGLT1 and GLUT5, and digestive enzymes APN and SI. Expression of these genes was measured in YSM at embryonic day (e) 11, 13, 15, 17, 19, 20, and 21 and small intestine at e15, e17, e19, e20, and e21. Absolute quantification real-time PCR assessed gene expression. PepT1, APN, and B0AT expression in YSM peaked between e15 and e17 and then decreased until e21, while expression increased over time in the small intestine. SGLT1 and EAAT3 expression increased over time in the small intestine and YSM. There was minimal gene expression of SI in the YSM, while the small intestine had high expression. GLUT5 and CAT1 expression decreased in the YSM, while peaking at e19 then decreasing in the small intestine. Breed and flock age affected expression levels in some genes. These results demonstrate that these genes show tissue- and development-specific patterns of expression and that the YSM expresses many digestive enzymes and nutrient transporters associated with the small intestine. Master of Science

Although it is well established that the presence of nutrients in the gut lumen can bring about changes in GI function, the mechanisms and pathways by which these changes occur has not been fully elucidated. It has been known for many years that luminal nutrients stimulate the release of hormones and regulatory peptides from gut endocrine cells and that luminal nutrients activate intrinsic and extrinsic neural pathways innervating the gut. Activation of gut endocrine cells and neural pathways by nutrients in the gut lumen is key in coordination of postprandial GI function and also in the regulation of food intake. Recent evidence suggests that these pathways can be modified by long term changes in diet or by inflammatory processes in the gut wall. Thus it is important to determine the cellular and molecular mechanisms underlying these processes not only to increase our understanding of as part of basic physiology but also to understand changes in these pathways that occur in the presence of pathophysiology and disease. This review summarizes some of the latest data that we have obtained, together with information from the other laboratories, which have elucidated some of the mechanisms involved in nutrient detection in the gut wall. The focus is on monosaccharides and protein hydrolysates as there is some evidence for a role for nutrient transporters in detection of these nutrients.

Fetal growth is primarily determined by nutrient availability, which is intimately related to placental nutrient transport. Detailed information on the regulation of placental nutrient transporters is therefore critical in order to understand the mechanisms underlying altered fetal growth and fetal programming. After briefly summarizing the cellular mechanisms for placental transport of glucose, amino acids and free fatty acids, we will discuss factors shown to regulate placental nutrient transporters and review the data describing how these factors are altered in pregnancy complications associated with abnormal fetal growth. We propose an integrated model of regulation of placental nutrient transport by maternal and placental factors in IUGR.

Publisher Summary This chapter describes the pathways of nutrient absorption and the relations with diet. It discusses the influence of age and the possible signals triggering the changes in absorptive functions. The different diets eaten during the development of most vertebrates place different functional demands on the gastrointestinal tract. These different diets are matched by age-related changes in the types, densities, and relative proportions of the various types of nutrient transporters. The transporters for most nutrients are first expressed prior to the onset of feeding. The ontogenetic changes occurring during the evolution of the species coincide with age-related modifications of gastrointestinal tract (GIT) structure and functions. The specific ontogenetic patterns of transporter development vary and correspond with the changes in dietary composition that have occurred during the evolution of species. As a consequence, the patterns vary among herbivores, omnivores, and carnivores. The specific patterns of development are the result of genetic determinants (internal factors) interacting with dietary inputs and other external factors. A better understanding of the age-related changes in nutrient absorption will enhance efforts to improve diets and feeding regimens for raising young, rapidly growing animals.

The trafficking of nutrient transporters is highly regulated and controlled by a variety of signal transduction pathways. A recent study by Gao and Kaiser (2006) in Nature Cell Biology demonstrates a role for a novel GTPase-containing complex that allows the amino acid permease Gap1 to recycle out of late endosomal compartments. This complex is likely to play critical roles in allowing animal cells to mobilize their nutrient transporters in response to metabolic demands.

Natural selection tends to eliminate unutilized capacities because of their costs. Hence we ask how large are the reserve capacities by which biological capacities exceed natural loads, and how closely are related biological capacities matched to each other. Measured capacities (Vmax values) of small intestinal brush-border nutrient transporters are typically around twice their natural loads (dietary intakes of their substrates); the ratio is higher for a transporter of a hyperessential nutrient. Preliminary evidence suggests matching of capacities between different steps in carbohydrate metabolism, and between the intestine, liver, kidneys, and spleen. Symmorphosis — the postulated matching of capacities to each other and to loads — is a testable hypothesis of economic design, useful in detecting and explaining cases of apparently uneconomic design.