This study was conducted to investigate whether methionyl-tRNA synthetase (MetRS) is a mediator of methionine (Met)-induced crop milk protein synthesis via the janus kinase 2 (JAK2)/signal transducer and activator of transcription 5 (STAT5) signalling pathway in breeding pigeons. In Experiment 1, a total of 216 pairs of breeding pigeons were divided into three groups (control, Met-deficient, and Met-rescue groups). In Experiments 2 and 3, forty pairs of breeding pigeons from each experiment were allocated into four groups. The second experiment included a control group and three MetRS inhibitor (REP8839) groups. The third experiment included a Met-deficient group, Met-sufficient group, REP8839 + Met-deficient group and REP8839 + Met-sufficient group. Experiment 1 showed that Met supplementation increased crop development, crop milk protein synthesis, the protein expression of MetRS and JAK2/STAT5 signalling pathway, and improved squab growth. Experiment 2 showed that crop development, crop milk protein synthesis and the protein expression of MetRS and the JAK2/STAT5 signalling pathway were decreased, and squab growth was inhibited by the injection of 1·0 mg/kg body weight REP8839, which was the selected dose for the third experiment. Experiment 3 showed that Met supplementation increased crop development, crop milk protein synthesis and the expression of MetRS and JAK2/STAT5 signalling pathway and rescued squab growth after the injection of REP8839. Moreover, the co-immunoprecipitation results showed that there was an interaction between MetRS and JAK2. Taken together, these findings indicate that MetRS mediates Met-induced crop milk protein synthesis via the JAK2/STAT5 signalling pathway, resulting in improved squab growth in breeding pigeons.

Nutrition in early life has a long-term influence on later health. In order to the explore effects of in ovo feeding (IOF) of vitamin C on splenic development, splenic metabolism and apoptosis were detected in embryo, adult chickens and in vitro. A total of 360 fertile eggs were selected and randomly assigned to control (CON) and vitamin C (VC) groups which were injected with saline and vitamin C on embryonic day 11, respectively. Functional enrichment of differentially expressed genes by transcriptome on embryonic day 19 suggested that purine nucleotide metabolism might be a potential pathway for the IOF of vitamin C to regulate spleen development. Additionally, the IOF of vitamin C significantly increased splenic vitamin C content on post-hatch day 21. Meanwhile, the splenic expression of adenosine deaminase, serine/threonine kinase 1 and proliferating cell nuclear antigen was down-regulated, whereas the expression of cysteinyl aspartate specific proteinase 9 was up-regulated in the VC group. On post-hatch day 42, the IOF of vitamin C significantly down-regulated the splenic expression of B-cell lymphoma 2 and increased the mRNA level of cysteinyl aspartate specific proteinase 9. The IOF of vitamin C could regulate the expression of genes related to adenylate metabolism and increased the apoptosis rate in vitro, which is consistent with the result in vivo. In conclusion, the IOF of vitamin C regulated splenic development and maturation by affecting purine nucleotide metabolism pathway and promoting apoptosis.

Bile acids (BA) have emerged as signalling molecules regulating intestinal physiology. The importance of intestinal microbiota in production of secondary BA, for example, lithocholic acid (LCA) which impairs enterocyte proliferation and permeability, triggered us to determine the effects of oral probiotics on intestinal BA metabolism. Piglets were weaned at 28 d of age and allocated into control (CON, n 14) or probiotic (PRO, n 14) group fed 50 mg of Lactobacillus plantarum daily, and gut microbiota and BA profile were determined. To test the potential interaction of LCA with bacteria endotoxins in inducing damage of enterocytes, IPEC-J2 cells were treated with LCA, lipopolysaccharide (LPS) and LCA + LPS and expressions of genes related to inflammation, antioxidant capacity and nutrient transport were determined. Compared with the CON group, the PRO group showed lower total LCA level in the ileum and higher relative abundance of the Lactobacillus genus in faeces. In contrast, the relative abundances of Bacteroides, Clostridium_sensu_stricto_1, Parabacteroides and Ruminococcus_1, important bacteria genera in BA biotransformation, were all lower in the PRO than in the CON group. Moreover, PRO piglets had lower postprandial glucagon-like peptide-1 level, while higher glucose level than CON piglets. Co-administration of LPS and LCA led to down-regulated expression of glucose and peptide transporter genes in IPEC-J2 cells. Altogether, oral L. plantarum altered BA profile probably by modulating relative abundances of gut microbial genera that play key roles in BA metabolism and might consequently impact glucose homoeostasis. The detrimental effect of LCA on nutrient transport in enterocytes might be aggravated under LPS challenge.

The experiment was conducted to investigate the effects of dietary threonine (Thr) on growth performance and muscle growth, protein synthesis and antioxidant-related signalling pathways of hybrid catfish Pelteobagrus vachelli♀ × Leiocassis longirostris♂. A total of 1200 fish (14·19 (se 0·13) g) were randomly distributed into six groups with four replicates each, fed six diets with graded level of Thr (9·5, 11·5, 13·5, 15·4, 17·4 and 19·3 g/kg diets) for 56 d. Results showed (P < 0·05) that dietary Thr (1) increased percentage weight gain, specific growth rate, feed efficiency and protein efficiency ratio; (2) up-regulated growth hormone (GH), insulin-like growth factor 1 (IGF-1), proliferating cell nuclear antigen, myogenic regulation factors (MyoD, Myf5, MyoG and Mrf4) and myosin heavy chain (MyHC) mRNA levels; (3) increased muscle protein content via regulating the protein kinase B/target of rapamycin signalling pathway and (4) decreased malondialdehyde and protein carbonyl contents, increased catalase, glutathione-S-transferase, glutathione reductase and GSH activities, up-regulated mRNA levels of antioxidant enzymes related to NFE2-related factor 2 and γ-glutamylcysteine ligase catalytic subunit. These results suggest that Thr has a potential role to improve muscle growth and protein synthesis, which might be due to the regulation of GH-IGF system, muscle growth-related gene, antioxidative capacity and protein synthesis-related signalling pathways. Based on the quadratic regression analysis of specific growth rate, the Thr requirement of hybrid catfish (14·19–25·77 g) was estimated to be 13·77 g/kg of the diet (33·40 g/kg of dietary protein).

Colonic effects of extruded whole-grain sorghum diets were evaluated using a model of growing rats. In all, twenty-four male Wistar rats were fed control (C), extruded white sorghum (EWS) or red sorghum (ERS). Consumption of sorghum diets showed satiety properties, with reduction of caecal pH, and lower activity of β-glucosidase and β-glucuronidase enzymes. Decreased copper zinc superoxide dismutase and manganese superoxide dismutase and increased catalase and glutathione peroxidase levels were observed in colonic mucosa. The induction of antioxidant enzymes occurred through the activation of the nuclear factor erythroid 2-related factor 2 protein and its subsequent translocation into the nucleus. ERS was able to decrease the proliferation of proximal mucosa of colon, demonstrating a possible effect against colorectal tumourigenesis. EWS increased proliferation and also apoptosis, ensuring the re-establishment of homoeostasis of the colonic mucosa. No antioxidant systemic effect (serum or hepatic level) was observed. It is likely that despite the extrusion the low bioavailability of the phenolic compounds of sorghum diets caused them to exert mainly acute effects at the colon level. Extruded whole-grain sorghum is a good functional ingredient that might be promising in dietary prevention of intestinal diseases.

Suboptimal intake of Zn is one of the most common nutritional problems worldwide. Previously, we have shown that Zn deficiency (ZD) produces oxidative and nitrosative stress in the lung of rats. We analyse the effect of moderate ZD on the expression of several intermediate filaments of the cytoskeleton, as well as the effect of restoring Zn during the refeeding period. Adult male rats were divided into three groups: Zn-adequate control (CO) group; ZD group; Zn-refeeding group. CerbB-2 and proliferating cell nuclear antigen (PCNA) expression was increased in the ZD group while the other parameters did not change. During the refeeding time, CerbB-2, cytokeratins, vimentin and PCNA immunostaining was higher than that in the CO group. The present findings indicate that the overexpression of some markers could lead to the fibrotic process in the lung. Perhaps ZD implications must be taken into account in health interventions because an inflammation environment is associated with ZD in the lung.

Proliferation of intimal vascular smooth muscle cells is an important component in the development of atherosclerosis. Ellagic acid is a phenolic compound present in fruits (raspberries, blueberries, strawberries) and walnuts. The present study investigated the effect of ellagic acid on the oxidised LDL (ox-LDL)-induced proliferation of rat aortic smooth muscle cells (RASMC). The study found that ellagic acid significantly inhibited ox-LDL-induced proliferation of RASMC and phosphorylation of extracellular signal-regulated kinase (ERK) 1/2.Furthermore, ellagic acid also blocked the ox-LDL-induced (inducible) cell-cycle progression and down regulation of the expression of proliferating cell nuclear antigen (PCNA) in RASMC. Therefore, ellagic acid reduced the amount of ox-LDL-induced proliferation of RASMC via inactivation of the ERK pathway and suppression of PCNA expression. These results may significantly advance the understanding of the role that antioxidants play in the prevention of atherosclerosis.

Objective: Analysis of the correlation between telomerase and the expression of its related proteins may provide insight into the molecular mechanism of nasopharyngeal carcinogenesis. We investigated the effect of short hair pin ribonucleic acid (RNA) specific for human telomerase reverse transcriptase messenger RNA on the expression of the proteins c-myc (the transcription factor c-myc is a shortlived nuclear phospho-protein involved in cell proliferation and differentiation, belongs to the myc family), proliferating cell nuclear antigen and Caspase-3 in nasopharyngeal carcinoma cells.

Methods: Short hairpin RNA expression vectors targeting the messenger RNA of human telomerase reverse transcriptase were constructed. Cells were treated with the short hairpin RNA expression vectors targeting human telomerase reverse transcriptase or vectors that included mismatched short hairpin RNA, and telomerase activity was measured by telomeric repeat amplification enzyme-linked immunosorbent assay. Cell viability was examined using the 3-(4,5-dimethyl thizol-2-yl) 2,5-diphenyl tetrazolium bromide assay. The expression of the three proteins (c-myc, proliferating cell nuclear antigen and Caspase-3) was determined by Western blotting.

Results: Short hairpin RNA specific for human telomerase reverse transcriptase messenger RNA significantly inhibited telomerase activity. In addition, the expression of and proliferating cell nuclear antigen were both inhibited, while the expression of Caspase-3 was up-regulated.

Conclusions: Our results suggest that short hairpin RNA directed against human telomerase reverse transcriptase inhibits cell viability by regulating telomerase activity and its related proteins expression in nasopharyngeal carcinoma cells. Therefore, RNA interference technology may be a promising strategy for the treatment of nasopharyngeal cancer.

The purpose of this study was to assess the significance of the expression of p21WAF1/Cip1 and proliferating cell nuclear antigen (PCNA) in human laryngeal squamous cell carcinomas. Forty-eight patients (25 supraglottic, 23 glottic) who had undergone operations between 1998 and 2003 were included in this study. The Envision immunohistochemistry method was utilized to stain these tissue specimens. The results showed that the immunostaining of p21WAF1/Cip1 do not show any correlation with differentiation, N stage, metastasis, survival, recurrence or the laryngeal site of involvement. A significant inverse correlation was detected between p21WAF1/Cip1 and the T stage. In contrast, the percentage of PCNA labelled cells showed a significant correlation with the T stage, but not with other clinicopathological parameters. There were differences in the expression of p21WAF1/Cip1 and PCNA between the supraglottic and the glottic carcinomas. In conclusion, our findings suggest that p21WAF1/Cip1 and PCNA may play an important role in the progression of carcinoma of the supraglottic larynx.

Albino vertebrates exposed to intense light typically lose photoreceptors via apoptosis, and thus serve as useful models of retinal degeneration. In contrast, albino rainbow trout exposed to intense light maintain populations of rod and cone nuclei despite substantial damage to rod outer segments (ROS). The aim of this study was to differentiate between two hypotheses that could account for this divergent result: (1) trout rod nuclei remain intact during light damage, or (2) rod nuclei die but are replaced by cell proliferation. A further aim was to examine whether photic history modulates retinal damage, as in rodents. Albino and normally pigmented trout were moved from defined photic regimes into full daylight, while some were not moved to serve as protected controls. ROS were always maintained in pigmented fish and in albinos protected from full daylight. In albinos exposed to full daylight, ROS were removed over most of the central retina, whereas rod nuclei were maintained in the outer nuclear layer over 10 days. Pyknotic and TUNEL-labeled rod nuclei were abundant in affected albinos at all time-points tested. Rod death occurred without a decrease in the number of rod nuclei, confirming that proliferation must be replacing cells. Indeed a transient increase in proliferation was observed in retinal progenitors of albinos receiving 5 days of damaging light. This proliferative response was decreased with further damage. Cones remained intact even in areas where rod nuclei had degenerated. Pretreatment with light of moderate versus low intensity light affected the cell death and proliferative responses, and the ectopic localization of rod opsin. We conclude that apoptotic demise of rods, but not cones, occurred during light damage in retinas of albino trout and proliferative responses have a limited a capacity to replace lost rods.

The identification of myogenic precursor cells (mpc) is a key factor in determining the early events in the myogenesis and regeneration of skeletal muscle. Although satellite cells have long been established as the providers of myoblastic cells, very little is really known (apart from their anatomical location in relation to muscle fibres and their ability to migrate) about the precise role of satellite cells in myogenesis. Numerous techniques for labelling mpc have been devised, but none of these has proven to be completely reliable in firmly establishing the origin of myogenic cells. The use of tritiated thymidine to label DNA in proliferating mpc (which are not specifically distinguishable at the time) and the subsequent location of their labelled progeny in myotube nuclei has revealed a great deal of data on the timing of myogenesis, but not about the nature of mpc themselves. DNA synthesis can also be detected by antibodies to the thymidine analogue, bromodeoxyuridine, and also by antibody staining for proliferating nuclear cell antigen. Like tritiated thymidine, these other markers are not specific for muscle but are general markers for DNA synthesis. In situ hybridisation of various muscle-specific genetic markers and their products has been informative, as has immunolabelling of myogenin, MyoD1 and desmin. Desmin labelling has been particularly instructive in identifying mpc because it is one of the first muscle-specific proteins to be produced in mpc. This review covers some of the techniques mentioned above and their usefulness in determining the early events in myogenesis.