Myostatin mRNA expression and its association with body weight and carcass traits in Yunnan Wuding chicken.

Myostatin (MSTN) is expressed in the myotome and developing skeletal muscles, and acts to regulate the number of muscle fibers. Wuding chicken large body, developed muscle, high disease resistance, and tender, delicious meat, and are not selected for fast growth. Broiler chickens (Avian broiler) are selected for fast growth and have a large body size and high muscle mass. Here, 240 one-day-old chickens (120 Wuding chickens and 120 broilers) were examined. Twenty chickens from each breed were sacrificed at days 1, 30, 60, 90, 120, and 150. Breast and leg muscle samples were collected within 20 min of sacrifice to investigate the effects of MSTN gene expression on growth performance and carcass traits. Body weight, carcass traits, and skeletal muscle mass in Wuding chickens were significantly (P < 0.05) lower than those in broiler chickens at all time points. Breast muscle MSTN mRNA was lower in Wuding chickens than in broilers before day 30 (P < 0.05). After day 30, breast muscle MSTN expression was higher in Wuding chicken than in broilers (P < 0.05). Leg muscle MSTN mRNA expression was higher in Wuding chicken than in broilers at all ages except for day 60 (P < 0.05). Correlation analysis revealed that breast muscle MSTN expression has a greater effect in slow growing Wuding chickens than in the fast growing broilers. In contract, leg muscle MSTN mRNA level has a greater effect in broilers than in Wuding chickens. MSTN regulates growth performance and carcass traits in chickens.

Comparison and analysis of Wuding and avian chicken skeletal muscle satellite cells.

Chicken skeletal muscle satellite cells are located between the basement membrane and the sarcolemma of mature muscle fibers. Avian broilers have been genetically selected based on their high growth velocity and large muscle mass. The Wuding chicken is a famous local chicken in Yunnan Province that undergoes non-selection breeding and is slow growing. In this study, we aimed to explore differences in the proliferation and differentiation properties of satellite cells isolated from the two chicken breeds. Using immunofluorescence, hematoxylin-eosin staining and real-time polymerase chain reaction analysis, we analyzed the in vitro characteristics of proliferating and differentiating satellite cells isolated from the two chicken breeds. The growth curve of satellite cells was S-shaped, and cells from Wuding chickens entered the logarithmic phase and plateau phase 1 day later than those from Avian chicken. The results also showed that the two skeletal muscle satellite cell lines were positive for Pax7, MyoD and IGF-1. The expression of Pax7 followed a downward trend, whereas that of MyoD and IGF-1 first increased and subsequently decreased in cells isolated from the two chickens. These data indicated that the skeletal muscle satellite cells of Avian chicken grow and differentiate faster than did those of Wuding chickens. We suggest that the methods of breeding selection applied to these breeds regulate the characteristics of skeletal muscle satellite cells to influence muscle growth.

Transcriptional analysis of atrial and ventricular muscles from rats.

Previous studies have used microarray technology to explore gene expression differences between the atrium and the ventricle. However, selection criteria for the differentially expressed genes (DEGs) based only on either the fold change or the P value in these studies. Here, we aim to further identify the DEGs by setting a P value threshold of <0.05 and a fold change of >2, which may yield more specific gene expression differences between the atrium and the ventricle. Gene expression profiling of the atrial appendages and the ventricular free walls in 13 normal male Sprague Dawley rats were obtained from the Gene Expression Omnibus data base (accession No.: GSE5266). DEGs between the atrial and the ventricular samples were screened using the microarray significance analysis. The underlying functions of DEGs were predicted by gene ontology and pathway enrichment analyses. In addition, we also constructed protein interactions networks, and analyzed the function modules of the interacting proteins by MCODE. A total of 757DEGs between the atria and the ventricles were found. The genes highly expressed in the ventricular myocytes were associated with muscle contraction (e.g., Myl1, Myl2, Myl3, and Myh7) and energy production (e.g., Acadm and Acsl6), while the genes preferentially expressed in the atrial myocytes were involved in the integration of neurohumoral signals (e.g., Cldn1). These conclusions were confirmed by pathway enrichment and function module analyses. Our present study provides an overview of the transcript level differences between the atrium and the ventricle, which may be useful for determination of potential biomarkers.

Analysis of skin color change and related gene expression after crossing of Dongxiang black chicken and ISA layer.

This study evaluated the effects of the autosomal domi-nant Fm gene in conjunction with the sex-linked Id gene on skin color and related gene expression. Ten Dongxiang black cocks were selected to build ten families by mating 60 individuals of ISA B-line layers. The skin color of the F1 generation was observed at different time points. At 126 days, 36 chickens were slaughtered, and gene expression of TYRP1, TYRP2, MC1R, and EDNRB in breast skin was assessed by quantitative RT-PCR. The ratio of Dongxiang black chickens with white skin chicks in the F1 generation to that of non-white was 3:7 (HoFF: HeFf). At 126 days, all F1 generation cocks showed white skin (115/115), while the percentages of hens with black skin were 100% (HoFF, 27/27) and 53.75% (HeFf, 43/80). The change in skin color peaked between 42 and 84 days. The offspring of HoFF displayed significantly higher expres-sion of MC1R, compared with those of HeFf (P < 0.05). The "L" value of hen's skin was significantly lower, and TYRP1 and TYRP2 expres-sion was significantly higher (P < 0.05) than in cocks with the same Fm/fm genotype. These findings indicate the presence of homozygous and heterozygous Fm in Dongxiang black chickens, with the offspring of homozygous birds showing a higher percentage of black skin percentage. The expression of the four genes studied was correlated with skin color, with TYRP1 and TYRP2 representing the most suitable molecular markers.

Screening the first set of polymorphic microsatellite loci in Lunella coronata granulata (Turbinidae).

Lunella coronata granulata, from the family Turbini-dae, is an economically important species. The first set of 10 poly-morphic microsatellite loci was screened from L. coronata granulata, and 30 individuals were used to analyze the degree of polymorphism in these loci. The level of observed and expected heterozygosity was 0.0667-0.7333 and 0.0644-0.6628, respectively. The polymorphism information content varied from 0.305 to 0.559. Eight loci were in Hardy-Weinberg equilibrium (HWE) (P > 0.05), while two loci devi-ated significantly from the HWE after Bonferroni's correction (P < 0.005). The isolated microsatellite loci can be utilized in studies of population genetic analysis and they provide important genetic mark-ers for construction of genetic linkage maps and genetic breeding of L. coronata granulata resources.

Development and characterization of microsatellite loci in Megalonibea fusca.

Megalonibea fusca is a commercially important large edible fish. In this study, the first set of 10 polymorphic microsatellite loci for M. fusca was developed and characterized. The number of alleles per locus ranged from two to five, with the observed and expected heterozygosities ranging from 0.0667 to 0.7667, and from 0.0644 to 0.5828, respectively. Most of the loci were in Hardy-Weinberg equilibrium (P > 0.05), except for two loci (Mf25 and Mf30) after a Bonferroni's correction (P < 0.005). These informative microsatellite markers will be useful in further studies of the population and conservation genetics of this species.

Isolation and characterization of novel polymorphic microsatellite loci in Atrina vexillum Born (Pinnidae).

The pen shell, Atrina vexillum Born, is an edible shellfish that is widely consumed in the Asia-Pacific region. In this study, 11 polymorphic microsatellite loci were isolated from A. vexillum, and 30 wild individuals were used to evaluate the degree of polymorphism of these markers. The number of alleles per locus ranged from 3 to 8. The polymorphism information content varied from 0.199 to 0.831. The observed and expected heterozygosities were 0.1000-0.8667 and 0.1244-0.8356, respectively. Two loci deviated significantly from the Hardy-Weinberg equilibrium (HWE) after a Bonferroni correction, while the other nine loci were at HWE. These microsatellite loci will be useful in further studies on population genetic analyses, and will provide important genetic data for the conservation and recovery of A. vexillum.

Identification of aac(2')-I type b aminoglycoside-modifying enzyme genes in resistant Acinetobacter baumannii.

The aim of this study was to investigate the mechanism underlying the drug resistance of Acinetobacter baumannii toward aminoglycosides. A total of 32 A. baumannii strains were identified by molecular identification and subsequently isolated. The isolates were then amplified by polymerase chain reaction to analyze the 9 aminoglycoside-modifying enzyme genes and 7 16S rRNA methylase genes. Five types of aminoglycoside-modifying enzyme genes and 1 type of 16S rRNA methylase gene were detected in the 32 drug-resistant A. baumannii strains. Positive genes included 7 detection modes, of which the all-6-gene-positive mode aac(2')-Ib+aac(3)-I+aac(6')-Ib+ant(3'')-I+aph(3')-I+armA exhibited the largest number of strains (12, 37.5%). The resistance of A. baumannii against aminoglycosides resulted from the presence of 5 types of aminoglycoside-modifying enzyme genes and the 16S rRNA methylase gene armA. This study is the first to isolate the aac(2')-Ib aminoglycoside-modifying enzyme gene from A. baumannii in a domestic clinical setting.

High-resolution melting curve analysis of the ADSL and LPL genes and their correlation with meat quality and blood parameters in chickens.

Adenylosuccinate lyase (ADSL) and lipoprotein lipase (LPL) are key enzymes in the metabolism of inosine monophosphate (IMP) and fat mass, which are important factors in meat quality evaluation. In this study, we selected 50 hens from the ISA B-line layers and Guangxi Yellow chickens, slaughtered the chickens at 120 days old, and analyzed polymorphisms in the ADSL and LPL genes using the high-resolution melting curve method. Blood lipid parameters, intramuscular fat (IMF), and IMP content were higher (P < 0.05) in Guangxi Yellow chickens than in ISA B-line layers, while LPL activity was lower (P < 0.05). In exon 2 of the ADSL gene, a C3484T mutation was identified. In both breeds, the CC genotype showed the highest IMP, and IMP was the lowest in the TT genotype. In the 5ꞌ regulatory region of the LPL gene, a C293T mutation was identified. In both breeds, the CC genotype showed the lowest LPL and IMF, while IMF was the highest in the TT genotype. The percentages of individuals with the TT type in the ADSL gene, which was associated with the lowest IMP, were 16.0 and 52.0% in Guangxi chickens and ISA layers, respectively. The percentages of individuals with the CC type of the LPL gene, which was associated with the lowest LPL and IMF, were 28.0 and 44.0%, respectively. The ADSL and LPL gene mutations are correlated with differences in meat quality in different chicken breeds, and high-resolution melting curve is an effective prediction technology for these mutations.

Isolation and characterization of novel microsatellite markers for molecular genetic diversity in Siganus fuscescens.

The rabbitfish Siganus fuscescens is an economically valuable species that is widely distributed throughout the estuaries, intertidal, and offshore coasts of the Indo-Pacific and eastern Mediterranean. Ten novel microsatellite loci from the genome of S. fuscescens were developed using the fast isolation protocol with amplified fragment length polymorphism of sequences containing repeats. Polymorphisms in these 10 microsatellite markers were determined from 32 wild individuals. The number of alleles per locus and the polymorphism information content ranged from 2 to 5 and from 0.059 to 0.668, respectively. The observed and expected heterozygosities varied from 0.063 to 0.781 and from 0.062 to 0.731, respectively. Although 1 locus (LZY-X7, P < 0.005) showed significant deviation from the Hardy-Weinberg equilibrium, no deviations were detected in the other 9 loci. These microsatellite loci may be useful for further population genetic studies, conservation studies, population structure assessment, and linkage map construction of S. fuscescens.

Polymorphisms in GJA1 and their association with growth traits in chicken.

This study aimed to screen single nucleotide polymorphisms (SNPs) in the chicken gap junction protein alpha 1 (GJA1) gene, and to investigate their association with five growth traits measured in 269 chickens encompassing Chinese indigenous Beijing-You (BJY) and commercial Cobb broiler (CB) populations. Four variants were detected in the chicken GJA1 gene, in which one synonymous mutation was located in an exon (C61223231T or c.-1110 C>T), two in an intron (A61229799C or c.5460 A>C, T61229928A or c.5589 T>A) and one in the promoter (A61230599C or c. 6260 A>C) regions. Genotyping was performed by high-resolution melting analysis (SNP in an exon) and DNA sequencing (SNP in the introns and promoter). Association analysis revealed that each SNP had a significant effect on growth traits in chicken. A higher level of genetic diversity was observed in the indigenous BJY breed than in the commercial CB breed. Strong linkage disequilibrium was observed between the C61223231T and A61229799C polymorphisms, and four previously undiscovered haplotypes (CA, TC, CC, TA) were constructed from those two mutations. Association analysis between haplotype combinations (diplotypes) and growth traits was highly significant where diplotype CC + CC was dominant for all traits. We speculated that GJA1 either is a major gene, or is associated with a major gene, affecting chicken growth traits. Therefore, further studies are needed in large populations to evaluate polymorphisms located in different regions of this gene, as well as its functional study, to better understand its role in muscle development in chicken.

Screening and characterization of new microsatellite markers in Fenneropenaeus penicillatus.

Fenneropenaeus penicillatus, with high protein and low fat, is a commercially important aquatic product in China. Microsatellite loci were developed according to the protocol of fast isolation by amplified fragment length polymorphism of sequences containing repeats. Eight new polymorphic microsatellite markers for F. penicillatus were identified, and 32 wild individuals were used to evaluate the degree of polymorphism of these markers. The polymorphism information content ranged from 0.2703 to 0.7598, and the number of alleles per locus varied from 3 to 6. The observed and expected heterozygosities were 0.1613-0.5556 and 0.2347-0.7387, respectively. No significant deviations from Hardy-Weinberg equilibrium (P > 0.00625) were detected. These polymorphic microsatellite loci will be useful to study the genetic diversity and population structure of F. penicillatus.

Characterization of new microsatellite markers of Siganus fuscescens (Siganidae).

Siganus fuscescens, which is a small commercially important marine fish, is wildly distributed in shallow waters throughout the tropical and subtropical Indo-Pacific and Eastern Mediterranean regions. It is part of a group known as rabbitfish. Fifteen new polymorphic microsatellite markers for S. fuscescens were identified, and 32 wild individuals were used to evaluate the degree of polymorphism of these markers. The number of alleles per locus ranged from 2 to 12, and the polymorphism information content ranged from 0.210 to 0.849. The observed and expected heterozygosities were 0.142-0.808 and 0.225-0.853, respectively. Although significant deviations from Hardy-Weinberg equilibrium were detected at 2 loci (Sf1-37-2 and Sf1-47), no significant deviations were detected at the other 13 loci. These microsatellite markers will provide a useful tool for studies on genetic diversity and differentiation of S. fuscescens.

Characterization of eight novel microsatellite markers in the green-lipped mussel Perna viridis (Mytilidae).

The green lipped mussel, also known as the Asian green mussel (Perna viridis) is a fast reproducing and valuable food source, but it is also considered an invasive species and can clog and damage pipes and marine equipment. Eight novel polymorphic microsatellite loci for P. viridis were isolated and characterized. Microsatellite polymorphism was evaluated in 30 individuals collected from Xiamen, China. The number of alleles per locus and the polymorphism information content ranged from 2 to 5 and from 0.3092 to 0.7031, respectively. The observed and expected heterozygosities were 0.1538-0.8400 and 0.1448-0.6833, respectively. The loci identified in this study could provide a useful tool for the genetic population structure analysis of P. viridis.

Isolation and characterization of new microsatellite markers in the pen shell Atrina pectinata (Pinnidae).

The pen shell, Atrina pectinata, is a commercially important bivalve species, widely consumed in the Asian Pacific region. We identified 16 new microsatellite makers for A. pectinata using a modified fast isolation by AFLP of sequences containing repeat protocols; 27 individuals were collected from Xiamen to evaluate the degree of polymorphism. The number of polymorphic alleles per locus ranged from 2 to 11. The observed and expected heterozygosities were 0.050-0.913 and 0.049-0.869, respectively. The loci identified in this study could provide a useful tool for research on genetic diversity and genetic differentiation of A. pectinata populations.

Differential expression analysis of porcine MDH1, MDH2 and ME1 genes in adipose tissues.

Malate dehydrogenases 1 and 2 (MDH1 and MDH2), and malic enzyme 1 (ME1) play important roles in the Krebs cycle for energy metabolism. The mRNA abundance changes of MDH1, MDH2 and ME1 genes were measured across six different adipose tissues from the leaner Landrace and fatty Rongchang pig breeds using quantitative real-time PCR. The mRNA of MDH1, MDH2 and ME1 was more abundant in fatty Rongchang pigs than in leaner Landrace pigs. In both breeds, females exhibited higher adipocyte volume and mRNA abundance of MDH1, MDH2 and ME1 compared with males. These values were higher in the subcutaneous adipose tissue compared with visceral adipose tissue. Furthermore, mRNA abundance changes of MDH1, MDH2 and ME1 have the remarked significant positive correlation with adipocyte volume across the six adipose tissue types. We conclude that there are breed-, gender- and tissue-specific expression patterns of ME1, MDH1 and MDH2, which highlight their potential as candidate genes for selecting for fat volume in pigs.