Nutrient restriction induces failure of reproductive function and molecular changes in hypothalamus–pituitary–gonadal axis in postpubertal gilts

People on a diet to lose weight may be at risk of reproductive failure. To investigate the effects of nutrient restriction on reproductive function and the underlying mechanism, changes of reproductive traits, hormone secretions and gene expressions in hypothalamus–pituitary–gonadal axis were examined in postpubertal gilts at anestrus induced by nutrient restriction. Gilts having experienced two estrus cycles were fed a normal (CON, 2.86 kg/d) or nutrient restricted (NR, 1 kg/d) food regimens to expect anestrus. NR gilts experienced another three estrus cycles, but did not express estrus symptoms at the anticipated fourth estrus. Blood samples were collected at 5 days’ interval for consecutive three times for measurement of hormone concentrations at the 23th day of the fourth estrus cycle. Individual progesterone concentrations of NR gilts from three consecutive blood samples were below 1.0 ng/mL versus 2.0 ng/mL in CON gilts, which was considered anestrus. NR gilts had impaired development of reproductive tract characterized by absence of large follicles (diameter ≥ 6 mm), decreased number of corepus lutea and atrophy of uterus and ovary tissues. Circulating concentrations of IGF-I, kisspeptin, estradiol, progesterone and leptin were significantly lower in NR gilts than that in CON gilts. Nutrient restriction down-regulated gene expressions of kiss-1, G-protein coupled protein 54, gonadotropin-releasing hormone, estrogen receptor α, progesterone receptor, leptin receptor, follicle-stimulating hormone and luteinizing hormone and insulin-like growth factor I in hypothalamus–pituitary–gonadal axis of gilts. Collectively, nutrient restriction resulted in impairment of reproductive function and changes of hormone secretions and gene expressions in hypothalamus–pituitary–gonadal axis, which shed light on the underlying mechanism by which nutrient restriction influenced reproductive function.     

S100A14, a Member of the EF-hand Calcium-binding Proteins,Is Overexpressed in Breast Cancer and Acts as a Modulator of HER2 Signaling

HER2 is overexpressed in 20–25% of breast cancers. Overexpression of HER2 is an adverse prognostic factor and correlates with decreased patient survival. HER2 stimulates breast tumorigenesis via a number of intracellular signaling molecules, including PI3K/AKT and MAPK/ERK. S100A14, one member of the S100 protein family, is significantly associated with outcome of breast cancer patients. Here, for the first time, we show that S100A14 and HER2 are coexpressed in invasive breast cancer specimens, and there is a significant correlation between the expression levels of the two proteins by immunohistochemistry. S100A14 and HER2 are colocalized in plasma membrane of breast cancer tissue cells and breast cancer cell lines BT474 and SK-BR3. We demonstrate that S100A14 binds directly to HER2 by co-immunoprecipitation and pull-down assays. Further study shows that residues 956–1154 of the HER2 intracellular domain and residue 83 of S100A14 are essential for the two proteins binding. Moreover, we observe a decrease of HER2 phosphorylation, downstream signaling, and HER2-stimulated cell proliferation in S100A14-silenced MCF-7, BT474, and SK-BR3 cells. Our findings suggest that S100A14 functions as a modulator of HER2 signaling and provide mechanistic evidence for its role in breast cancer progression.     

Genetic variants and underlying mechanisms influencing variance heterogeneity in maize

Traditional genetic studies focus on identifying genetic variants associated with the mean difference in a quantitative trait. Because genetic variants also influence phenotypic variation via heterogeneity, we conducted a variance‐heterogeneity genome‐wide association study to examine the contribution of variance heterogeneity to oil‐related quantitative traits. We identified 79 unique variance‐controlling single nucleotide polymorphisms (vSNPs) from the sequences of 77 candidate variance‐heterogeneity genes for 21 oil‐related traits using the Levene test (P < 1.0 × 10^?5). About 30% of the candidate genes encode enzymes that work in lipid metabolic pathways, most of which define clear expression variance quantitative trait loci. Of the vSNPs specifically associated with the genetic variance heterogeneity of oil concentration, 89% can be explained by additional linked mean‐effects genetic variants. Furthermore, we demonstrated that gene × gene interactions play important roles in the formation of variance heterogeneity for fatty acid compositional traits. The interaction pattern was validated for one gene pair (GRMZM2G035341 and GRMZM2G152328) using yeast two‐hybrid and bimolecular fluorescent complementation analyses. Our findings have implications for uncovering the genetic basis of hidden additive genetic effects and epistatic interaction effects, and we indicate opportunities to stabilize efficient breeding and selection of high‐oil maize (Zea mays L.).     

Assembly and stoichiometry of FliF and FlhA in Salmonella flagellar basal body

The bacterial flagellar export apparatus is required for the construction of the bacterial flagella beyond the cytoplasmic membrane. The membrane‐embedded part of the export apparatus, which consists of FlhA, FlhB, FliO, FliP, FliQ and FliR, is located in the central pore of the MS ring formed by 26 copies of FliF. The C‐terminal cytoplasmic domain of FlhA is located in the centre of the cavity within the C ring made of FliG, FliM and FliN. FlhA interacts with FliF, but its assembly mechanism remains unclear. Here, we fused yellow fluorescent protein (YFP) and cyan fluorescent protein (CFP) to the C‐termini of FliF and FlhA and investigated their subcellular localization by fluorescence microscopy. The punctate pattern of FliF–YFP localization required FliG but neither FliM, FliN, FlhA, FlhB, FliO, FliP, FliQ nor FliR. In contrast, FlhA–CFP localization required FliF, FliG, FliO, FliP, FliQ and FliR. The number of FlhA–YFP molecules associated with the MS ring was estimated to be about nine. We suggest that FlhA assembles into the export gate along with other membrane components during the MS ring complex formation in a co‐ordinated manner.     

Involvement of P2Y<Subscript>12</Subscript> receptor of stellate ganglion in diabetic cardiovascular autonomic neuropathy

Diabetes as a chronic epidemic disease with obvious symptom of hyperglycemia is seriously affecting human health globally due to the diverse diabetic complications. Diabetic cardiovascular autonomic neuropathy (DCAN) is a common complication of both type 1 and type 2 diabetes and incurs high morbidity and mortality. However, the underlying mechanism for DCAN is unclear. It is well known that purinergic signaling is involved in the regulation of cardiovascular function. In this study, we examined whether the P2Y₁₂ receptor could mediate DCAN-induced sympathetic reflexes. Our results revealed that the abnormal changes of blood pressure, heart rate, heart rate variability, and sympathetic nerve discharge were improved in diabetic rats treated with P2Y₁₂ short hairpin RNA (shRNA). Meanwhile, the expression of P2Y₁₂ receptor, interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and connexin 43 (Cx43) in stellate ganglia (SG) was decreased in P2Y₁₂ shRNA-treated diabetic rats. In addition, knocking down the P2Y₁₂ receptor also inhibited the activation of p38 MARK in the SG of diabetic rats. Taken together, these findings demonstrated that P2Y₁₂ receptor in the SG may participate in developing diabetic autonomic neuropathy, suggesting that the P2Y₁₂ receptor could be a potential therapeutic target for the treatment of DCAN.     

The role of reactive oxygen species in the virulence of wheat leaf rust fungus Puccinia triticina

Reactive oxygen species (ROS) play an important role during host–pathogen interactions and are often an indication of induced host defence responses. In this study, we demonstrate for the first time that Puccinia triticina (Pt) generates ROS, including superoxide, H₂O₂ and hydroxyl radicals, during wheat infection. Through pharmacological inhibition, we found that ROS are critical for both Pt urediniospore germination and pathogenic development on wheat. A comparative RNA-Seq analysis of different stages of Pt infection process revealed 291 putative Pt genes associated with the oxidation–reduction process. Thirty-seven of these genes encode known proteins. The expressions of five Pt genes, including PtNoxA, PtNoxB, PtNoxR, PtCat and PtSod, were subsequently verified using RT-qPCR analysis. The results show that the expressions of PtNoxA, PtNoxB, PtNoxR, PtCat and PtSod are up-regulated during urediniospore germination. In comparison, the expressions of PtNoxA, PtNoxB, PtNoxR and PtCat are down-regulated during wheat infection from 12 to 120 h after inoculation (HAI), whereas the expression of PtSod is up-regulated with a peak of expression at 120 HAI. We conclude that ROS are critical for the full virulence of Pt and a coordinate down-regulation of PtNox genes may be important for successful infection in wheat.     

Effects of thioredoxin on the preimplantation development of bovine embryos

Thioredoxin (TRX) is an ubiquitous protein disulfide reductase, which is known to be involved in the implantation development of mouse embryos. In the present study, recombinant human TRX was used to evaluate its effect on the promotion of preimplantation development of bovine embryos derived from in vitro maturation and fertilization. Supplementation of the medium 24h post insemination with TRX significantly (P<0.05) enhanced the frequency of development to the blastocyst stage in 5% O(2) concentration. The optimal concentration was 0.5 microg/ml (P<0.05, compared with 0, 0.1 and 1.0 microg/ml). This effect of TRX was evident only when added around the time of the first cleavage stage (24 h post insemination); no promotion was found with treatment at 6h (one-cell) or 44 h (six- to eight-cell) after insemination. Moreover, it is of interest that even with the best combination of the dose and timing of TRX treatment (0.5 microg/ml, at 24 h post insemination), no promotion of development was observed when embryos were cultured under 20% O(2). However, a preincubation of TRX in the culture medium under 20% oxygen for 24h did not diminish the promoting effect in the subsequent TRX treatment under optimal conditions, thus suggesting that the possible oxidation of TRX alone may not be the reason for the disappearance of the effect under a high oxygen concentration. These results indicate that TRX does improve the development of bovine embryos in vitro, though unlike the general reducing reagents such as beta-mercaptoethanol or cysteamine, TRX may have to exert its effect at specific times and in more physiologic oxygen environments.     

Microbial succession in the traditional Chinese Luzhou-flavor liquor fermentation process as evaluated by SSU rRNA profiles

The community succession of microbes inhabited in the fermenting lees of Luzhou-flavor liquor was investigated based on small-subunit rRNA culture independent method. All sequences recovered from fermenting lees respectively fell into the genera of Lactobacillus, Streptococcus, Bacillus, Staphylococcus, Clostridium, Pelobacter, Actobacter, Serratia, Burkholderia, Rhodoccous, Corynebacterium, Arthrobacter, Microbacterium, Curtobacterium, Leptotrichia, Methanocuuleus, Saccharomyces, Zygosaccharomyces, Saccharomycopsis, Pichia, Talaromyces, Aspergillus, Eurotium, Fomitopsis and Trichosporon. The fungal Pichia, Saccharomycopsis and Talaromyces were most abundant in the lees fermented for 1 day, the fungal Eurotium and the bacteria Burkholderia, Streptococcus and Lactobacillus were dominant in the lees fermented for 7 days, only the bacteria Lactobacillus, Burkholderia were prevalent in the lees fermented for 60 days. Most genera almost existed in the fermenting lees, while their distributions were significantly different in 1, 7 and 60 days fermented lees. The prokaryotic community similarity coefficient was from 0.5000 to 0.5455 and followed to 0.1523, and that of eukaryotic community was from 0.5466 to 0.5259 and to 0.3750 when compared at species level. These results suggested that many microbes in lees have community successions associated with fermenting and that such successions maybe contribute the fermentation process of Luzhou-flavor liquor and is main reasons that the characteristic flavor factors are produced.     

GIV: A Tool for Genomic Islands Visualization

A Genomic Islands (GI) is a chunk of DNA sequence in a genome whose origin can be traced back to other organisms or viruses. The detection of GIs plays an indispensable role in biomedical research, due to the fact that GIs are highly related to special functionalities such as disease-causing GIs - pathogenicity islands. It is also very important to visualize genomic islands, as well as the supporting features corresponding to the genomic islands in the genome. We have developed a program, Genomic Island Visualization (GIV), which displays the locations of genomic islands in a genome, as well as the corresponding supportive feature information for GIs. GIV was implemented in C++, and was compiled and executed on Linux/Unix operating systems.

Availability

GIV is freely available for non-commercial use at http://www5.esu.edu/cpsc/bioinfo/software/GIV