Transcriptome analysis reveals the genetic basis of crest cushion formation in duck

The Chinese crested duck is a unique duck breed having a bulbous feather shape on its duck head.However,the mechanisms involved in its formation and development are unclear.In the present study,RNA sequencing analysis was performed on the crested tissues of 6 Chinese crested ducks and the scalp tissues of 6 cherry valley ducks(CVs)from 2 developmental stages.This study identified 261 differentially expressed genes(DEGs),122 upregulated and 139 downregulated,in the E28 stage and 361 DEGs,154 upregulated and 207 downregulated in the D42 stage between CC and CV ducks.The subsequent results of weighted gene co-expression network analysis(WGCNA)revealed that the turquoise and cyan modules were associated with the crest trait in the D42 stage,meanwhile,the green,brown,and pink modules were associated with the crest trait in the E28 stage.Venn analysis of the DEGs and WGCNA showed that 145 and 45 genes are associated between the D42 and E28 stages,respectively.The expression of WNT16,BMP2,SLC35F2,SLC6A15,APOBEC2,ABHD6,TNNC2,MYL1,and TNNI2 were verified by real-time quantitative PCR.This study provides an approach to reveal the molecular mechanisms underlying the crested trait development.

Anisotropy of mechanical properties of 2297-T87 Al–Li alloy thick plates

The tensile properties of 2297-T87 Al–Li alloy thick plates at different thickness position and in different direction were analyzed via tensile testing,optical microscopy(OM),X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive spectrometry(EDS),and transmission electron microscopy(TEM).Results indicated that the ultimate tensile strength(UTS)and yield strength(YS)of the alloy decreased firstly and then increased from the 1/8T position to the 1/2T position,whereas elongation to failure(Ef)decreased gradually such that its value along the rolling direction(RD)was higher than those along the transverse direction(TD)at the same thickness position.From the 1/8T position to the 3/8T position of the alloy,the UTS and YS along the TD were higher than those along the RD.At the 1/2T position of the alloy,the UTS,YS,and Ef along the RD were the highest,whereas those along the normal direction(ND)were the lowest.Microstructural observations further revealed that the anisotropy of tensile properties was related to grain morphology,crystal texture,second-phase particles,and Li atom segregation.

Gene expression of vascular endothelial growth factor A and hypoxic adaptation in Tibetan pig

Background： Vascular endothelial growth factor A （VEGFA） can induce endothelial cell proliferation, promote cell migration, and inhibit apoptosis. These processes play key roles in physiological blood vessel formation and pathological angiogenesis. Methods： In this study, we examined VEGFA gene expression in the heart, liver, and kidney of Tibetan pigs （-I-P）, Yorkshire pigs that migrated to high altitudes （YH）, and Yorkshire pigs that lived at low altitudes （YL）. We used PCR and Sanger sequencing to screen for single nucleotide polymorphisms （SNPs） in 5＇-flanking DNA and exons of the VEGFA gene. Quantitative real-time PCR and western blots were used to measure expression levels and PCR products were sequenced. Results： Results showed that the VEGFA mRNA and protein expression in heart, liver and kidney of TP was higher than that in YH and YL. In addition, the mRNA sequence of the pig VEGFA gene was conserved among pig breeds, and only five SNPs were found in the 5＇-flanking region of the VEGFA gene, the allele frequency distributions of the 5 SNPs were not significantly different between the TP, Yorkshire （YL）, and Diannan small-ear （DN） pig populations. Conclusion： In conclusion, the Tibetan pig showed high tissues, which suggests that the VEGFA gene may play a levels of VEGFA gene expression in several hypoxic major functional role in hypoxic adaptation.

The First Crested Duck Genome Reveals Clues to Genetic Compensation and Crest Cushion Formation

The Chinese crested(CC)duck is a unique indigenous waterfowl breed,which has a crest cushion that affects its survival rate.Therefore,the CC duck is an ideal model to investigate the genetic compensation response to maintain genetic stability.In the present study,we first generated a chromosome-level genome of CC ducks.Comparative genomics revealed that genes related to tissue repair,immune function,and tumors were under strong positive selection,indicating that these adaptive changes might enhance cancer resistance and immune response to maintain the genetic stability of CC ducks.We also assembled a Chinese spot-billed(Csp-b)duck genome,and detected the structural variations(SVs)in the genome assemblies of three ducks(i.e.,CC duck,Csp-b duck,and Peking duck).Functional analysis revealed that several SVs were related to the immune system of CC ducks,further strongly suggesting that genetic compensation in the anti-tumor and immune systems supports the survival of CC ducks.Moreover,we confirmed that the CC duck originated from the mallard ducks.Finally,we revealed the physiological and genetic basis of crest traits and identified a causative mutation in TAS2R40 that leads to crest formation.Overall,the findings of this study provide new insights into the role of genetic compensation in adaptive evolution.

Proteomic and phosphoproteomic analysis reveal threonine deficiency increases hepatic lipid deposition in Pekin ducks via reducing STAT phosphorylation

Dietary threonine(Thr)deficiency enhances triglyceride(TG)deposition in the liver of Pekin ducks,which injures hepatic function and impairs growth performance.However,the underlying molecular mechanisms remain unclear.In the present study,we investigated the effects of dietary Thr deficiency on the expressions of proteins and phosphoproteins in liver of Pekin ducks,to identify the underlying molecular changes.A total of 300 one-day-old ducklings were divided into 3 groups with 10 replicates of 10 birds.All ducks were fed corn-wheat-peanut meal diets containing 0.46%,0.71%,and 0.96%Thr,respectively,from 1 to 21 days of age.Growth performance,serum parameters,hepatic TG content,and expression of genes involved in lipid metabolism of Pekin ducks were determined.A Thr deficiency group(Thr-D,0.46%Thr)and a Thr sufficiency group(Thr-S,0.71%Thr)were selected for subsequent proteomic and phosphoproteomic analysis.The results showed that Thr-D reduced the growth performance(P<0.001),and increased the plasma concentrations of cholesterol,high-density lipoprotein cholesterol,low-density lipoprotein cholesterol,and hepatic TG(P<0.05).Thr-D increased gene expression related to fatty acid and TG synthesis(P<0.05).A total of 176 proteins and 259 phosphosites(containing 198 phosphoproteins)were observed to be differentially expressed as a result of Thr-D.The upregulated proteins were enriched in the pathway related to amino acid metabolism,peroxisome.The down-regulated proteins were enriched in linolenic and arachidonic acid metabolism,and the Janus kinase-signal transducer and activator of transcription(JAK-STAT)signaling pathway.The upregulated phos-phoproteins were enriched in the pathways related to fatty acid biosynthesis,fructose and mannose metabolism,and glycolysis/gluconeogenesis.Thr-D reduced the phosphorylation of STAT1 at S729 and STAT3 at S728,and expression of STAT5B.In contrast,Thr-D increased non-receptor tyrosine-protein kinase(TYK2)expression and STAT1 phosphorylation at S649.Taken together,dietary Thr-D increased hepatic TG accumulation by upregulating the expression of genes and proteins,and phosphoproteins related to fatty acid and triglyceride synthesis.Furthermore,these processes might be regulated by the JAK-STAT signaling pathway,especially the phosphorylation of STAT1 and STAT3.

Studies towards Bioinspired Synthesis of Hetidine-Type C20-Diterpenoid Alkaloids

Details of a biogenetically inspired strategy that led to the synthesis of the hetidine-type C20-diterpenoid alka- loid skeleton are reported in this paper. Key steps of our synthesis include a C-H oxidation to convert the atis- ine-type core to the ajaconine skeleton, as well as an aza-Prins cyclization that establishes the hetidine alkaloid skeleton. An unexpected heptacyclic framework bearing a unique tricyclo[3.3.1.02.7]nonane moiety has been ob- tained during our studies, which may represent a new type of C20-diterpenoid alkaloids yet to be discovered.

Preparation and Characterization of Ultra-thin Pd-Ag Alloy Membranes

Ultra-thin Pd-Ag alloy membranes were prepared initially by cold rolling, and it was found that there exist a large number of defects such as pinholes or cracks in the as-rolled membranes. Subsequently, these defects were repaired using electroless plating technique. The morphologies of the membranes have been examined by scanning electron microscopy （SEM）. It was observed in some as-repaired membranes that the defects were disappeared. A hydrogen permeation study has demonstrated that the as-repaired Pd-Ag alloy membranes were of high hydrogen permeation flux and hydrogen selectivity.