Strigolactones (SLs) are carotenoid-derived phytohormones that control many aspects of plant development, including shoot branching, leaf shape, stem secondary thickening, and lateral root growth. In rice (Oryza sativa), SL signaling requires the degradation of DWARF53 (D53), mediated by a complex including D14 and D3, but in Arabidopsis thaliana, the components and mechanism of SL signaling involving the D3 ortholog MORE AXILLARY GROWTH2 (MAX2) are unknown. Here, we show that SL-dependent regulation of shoot branching in Arabidopsis requires three D53-like proteins, SUPPRESSOR OF MORE AXILLARY GROWTH2-LIKE6 (SMXL6), SMXL7, and SMXL8. The smxl6 smxl7 smxl8 triple mutant suppresses the highly branched phenotypes of max2 and the SL-deficient mutant max3. Overexpression of a mutant form of SMXL6 that is resistant to SL-induced ubiquitination and degradation enhances shoot branching. Exogenous application of the SL analog rac-GR24 causes ubiquitination and degradation of SMXL6, 7, and 8; this requires D14 and MAX2. D53-like SMXLs form complexes with MAX2 and TOPLESS-RELATED PROTEIN2 (TPR2) and interact with D14 in a GR24-responsive manner. Furthermore, D53-like SMXLs exhibit TPR2-dependent transcriptional repression activity and repress the expression of BRANCHED1. Our findings reveal that in Arabidopsis, D53-like SMXLs act with TPR2 to repress transcription and so allow lateral bud outgrowth but that SL-induced degradation of D53-like proteins activates transcription to inhibit outgrowth.

Proline plays important roles in protein synthesis and structure, metabolism (particularly the synthesis of arginine, polyamines, and glutamate via pyrroline-5-carboxylate), and nutrition, as well as wound healing, antioxidative reactions, and immune responses. On a pergram basis, proline plus hydroxyproline are most abundant in collagen and milk proteins, and requirements of proline for whole-body protein synthesis are the greatest among all amino acids. Therefore, physiological needs for proline are particularly high during the life cycle. While most mammals (including humans and pigs) can synthesize proline from arginine and glutamine/glutamate, rates of endogenous synthesis are inadequate for neonates, birds, and fish. Thus, work with young pigs (a widely used animal model for studying infant nutrition) has shown that supplementing 0.0, 0.35, 0.7, 1.05, 1.4, and 2.1% proline to a proline-free chemically defined diet containing 0.48% arginine and 2% glutamate dose dependently improved daily growth rate and feed efficiency while reducing concentrations of urea in plasma. Additionally, maximal growth performance of chickens depended on at least 0.8% proline in the diet. Likewise, dietary supplementation with 0.07, 0.14, and 0.28% hydroxyproline (a metabolite of proline) to a plant protein-based diet enhanced weight gains of salmon. Based on its regulatory roles in cellular biochemistry, proline can be considered as a functional amino acid for mammalian, avian, and aquatic species. Further research is warranted to develop effective strategies of dietary supplementation with proline or hydroxyproline to benefit health, growth, and development of animals and humans.

Dietary supplementation of glutamine prevents intestinal dysfunction and atrophy in weanling piglets, but the underlying mechanism(s) are largely unknown. This study was conducted to test the hypothesis that weaning or glutamine may modulate expression of genes that are crucial for intestinal metabolism and function. In Expt. 1, we obtained small intestine from 28-d-old pigs weaned at 21 d of age and from age-matched suckling piglets. In Expt. 2, piglets were weaned at 21 d of age and then had free access to diets supplemented with 1% L-glutamine (wt:wt) or isonitrogenous L-alanine (control). At d 28, we collected small intestine for biochemical and morphological measurements and microarray analysis of gene expression using the Operon Porcine Genome Oligo set. Early weaning resulted in increased (52-346%) expression of genes related to oxidative stress and immune activation but decreased (35-77%) expression of genes related to macronutrient metabolism and cell proliferation in the gut. Dietary glutamine supplementation increased intestinal expression (120-124%) of genes that are necessary for cell growth and removal of oxidants, while reducing (34-75%) expression of genes that promote oxidative stress and immune activation. Functionally, the glutamine treatment enhanced intestinal oxidative-defense capacity (indicated by a 29% increase in glutathione concentration), prevented jejunal atrophy, and promoted small intestine growth (+12%) and body weight gain (+19%) in weaned piglets. These findings reveal coordinate alterations of gene expression in response to weaning and aid in providing molecular mechanisms for the beneficial effect of dietary glutamine supplementation to improve nutrition status in young mammals.

Embryonic loss and intrauterine growth restriction (IUGR) are significant problems in humans and other animals. Results from studies involving pigs and sheep have indicated that limited uterine capacity and placental insufficiency are major factors contributing to suboptimal reproduction in mammals. Our discovery of the unusual abundance of the arginine family of amino acids in porcine and ovine allantoic fluids during early gestation led to the novel hypothesis that arginine plays an important role in conceptus (embryo and extra-embryonic membranes) development. Arginine is metabolized to ornithine, proline, and nitric oxide, with each having important physiological functions. Nitric oxide is a vasodilator and angiogenic factor, whereas ornithine and proline are substrates for uterine and placental synthesis of polyamines that are key regulators of gene expression, protein synthesis, and angiogenesis. Additionally, arginine activates the mechanistic (mammalian) target of rapamycin cell signaling pathway to stimulate protein synthesis in the placenta, uterus, and fetus. Thus, dietary supplementation with 0.83 % L-arginine to gilts consuming 2 kg of a typical gestation diet between either days 14 and 28 or between days 30 and 114 of pregnancy increases the number of live-born piglets and litter birth weight. Similar results have been reported for gestating rats and ewes. In sheep, arginine also stimulates development of fetal brown adipose tissue. Furthermore, oral administration of arginine to women with IUGR has been reported to enhance fetal growth. Collectively, enhancement of uterine as well as placental growth and function through dietary arginine supplementation provides an effective solution to improving embryonic and fetal survival and growth.

Nutrients in uterine secretions are essential for development and survival of conceptuses (embryo and associated extraembryonic membranes) during pregnancy; however, little is known about changes in the amounts of specific nutrients in the uterine fluids of cyclic and pregnant ruminants. This study determined quantities of glucose, amino acids, glutathione, calcium, sodium, and potassium in uterine lumenal fluid from cyclic (Days 3-16) and pregnant (Days 10-16) ewes. Total recoverable glucose, Arg, Gln, Leu, Asp, Glu, Asn, His, beta-Ala, Tyr, Trp, Met, Val, Phe, Ile, Lys, Cys, Pro, glutathione, calcium, and sodium were greater in the uterine fluid of pregnant compared with cyclic ewes between Days 10 and 16. In cyclic ewes, only modest changes in the total amounts of glucose, Asn, Cit, Tyr, Trp, Met, Val, Cys, glutathione, calcium, and potassium were detected between Days 3 and 16. However, in pregnant ewes, amounts of glucose, Arg, Gln, Glu, Gly, Cys, Leu, Pro, glutathione, calcium, and potassium in uterine fluids increased 3- to 23-fold between Days 10 and 14 and remained high to Day 16. Of particular interest were increases in glucose, Arg, Leu, and Gln in uterine flushings of pregnant ewes between Days 10 and 16 of pregnancy. Total amounts of His, ornithine, Lys, Ser, Thr, Ile, Phe, Trp, Met, and Cit in uterine fluids also increased, but to a lesser extent during early pregnancy. These novel results indicate activation of pregnancy-associated mechanisms for transport of nutrients into the uterine lumen, and they provide a framework for future studies of nutrients, including glucose, amino acids, and glutathione, required to activate nutrient-sensing cell signaling pathways for growth, development, and survival of conceptuses, as well as for optimization of culture media for in vitro studies of conceptus development.

Objective Hyperchloremia is frequently observed in critically ill patients in the intensive care unit (ICU). Our study aimed to examine the association of serum chloride (Cl) levels with hospital mortality in septic ICU patients. Design Retrospective cohort study. Setting Urban academic medical center ICU. Patients ICU adult patients with severe sepsis or septic shock who had Cl measured on ICU admission were included. Those with baseline estimated glomerular filtration rate < 15 ml/min/1.73 m2 or chronic dialysis were excluded. Intervention: None. Measurements and Main Results Of 1940 patients included in the study, 615 (31.7%) had hyperchloremia (Cl ≥ 110 mEq/L) on ICU admission. All-cause hospital mortality was the dependent variable. Cl on ICU admission (Cl0), Cl at 72 h (Cl72), and delta Cl (ΔCl = Cl72 – Cl0) were the independent variables. Those with Cl0 ≥ 110 mEq/L were older and had higher cumulative fluid balance, base deficit, and sequential organ failure assessment scores. Multivariate analysis showed that higher Cl72 but not Cl0 was independently associated with hospital mortality in the subgroup of patients with hyperchloremia on ICU admission [adjusted odds ratio (OR) for Cl72 per 5 mEq/L increase = 1.27, 95% CI (1.02–1.59), P = 0.03]. For those who were hyperchloremic on ICU admission, every within-subject 5 mEq/L increment in Cl72 was independently associated with hospital mortality [adjusted OR for ΔCl 5 mEq/L = 1.37, 95% CI [1.11–1.69], P = 0.003]. Conclusions In critically ill septic patients manifesting hyperchloremia (Cl ≥110 mEq/L) on ICU admission, higher Cl levels and within-subject worsening hyperchloremia at 72 h of ICU stay were associated with all-cause hospital mortality. These associations were independent of base deficit, cumulative fluid balance, acute kidney injury, and other critical illness parameters.

This study tested the hypothesis that l-arginine (Arg) may stimulate cell proliferation and prevent lipopolysaccharide (LPS)-induced death of intestinal cells. Intestinal porcine epithelial cells (IPEC-1) were cultured for 4 days in Arg-free Dulbecco’s modified Eagle’s-F12 Ham medium (DMEM-F12) containing 10, 100 or 350 μM Arg and 0 or 20 ng/ml LPS. Cell numbers, protein concentrations, protein synthesis and degradation, as well as mammalian target of rapamycin (mTOR) and Toll-like receptor 4 (TLR4) signaling pathways were determined. Without LPS, IPEC-1 cells exhibited time- and Arg-dependent growth curves. LPS treatment increased cell death and reduced protein concentrations in IPEC-1 cells. Addition of 100 and 350 μM Arg to culture medium dose-dependently attenuated LPS-induced cell death and reduction of protein concentrations, in comparison with the basal medium containing 10 μM Arg. Furthermore, supplementation of 100 and 350 μM Arg increased protein synthesis and reduced protein degradation in both control and LPS-treated IPEC-1 cells. Consistent with the data on cell growth and protein turnover, addition of 100 or 350 μM Arg to culture medium increased relative protein levels for phosphorylated mTOR and phosphorylated ribosomal protein S6 kinase-1, while reducing the relative levels of TLR4 and phosphorylated levels of nuclear factor-κB in LPS-treated IPEC-1 cells. These results demonstrate a protective effect of Arg against LPS-induced enterocyte damage through mechanisms involving mTOR and TLR4 signaling pathways, as well as intracellular protein turnover.

Background Fewer than 1 in 5 patients receive hepatocellular carcinoma surveillance; however, most studies were performed in racially and socioeconomically homogenous populations and few used guideline-based definitions for surveillance. Aims To characterize guideline-consistent hepatocellular carcinoma surveillance rates and identify determinants of hepatocellular carcinoma surveillance among a racially and socioeconomically diverse cohort of cirrhotic patients. Methods We retrospectively characterized hepatocellular carcinoma surveillance among cirrhotic patients followed between July 2008 and July 2011 at an urban safety-net hospital. Inconsistent surveillance was defined as at least one screening ultrasound during the 3-year period, annual surveillance as screening ultrasounds every 12 months, and biannual surveillance as screening ultrasounds every 6 months. Univariate and multivariate analyses were conducted to identify predictors of surveillance. Results Of 904 cirrhotic patients, 603 (67%) underwent inconsistent surveillance. Failure to recognize cirrhosis was a significant barrier to surveillance utilization (p<0.001). Inconsistent surveillance was associated with insurance status (OR 1.43, 95%CI 1.03–1.98), multiple primary care visits per year (OR 2.63, 95%CI 1.86–3.71), multiple hepatology visits per year (OR 3.75, 95%CI 2.64–5.33), African American race (OR 0.61, 95%CI 0.42–0.99), nonalcoholic steatohepatitis etiology (OR 0.60, 95%CI 0.37–0.98), and extrahepatic cancer (OR 0.43, 95%CI 0.24–0.77). Only 98 (13.4%) of 730 patients underwent annual surveillance, and only 13 (1.7%) of 786 had biannual surveillance. Conclusions Only 13% of patients with cirrhosis receive annual surveillance and less than 2% receive biannual surveillance. There are racial and socioeconomic disparities, with lower rates of hepatocellular carcinoma surveillance among African Americans and underinsured patients.