SFRP2 affects prenatal muscle development and is regulated by micro RNA-1/206 in pigs

Secreted frizzled-related protein 2(SFRP2), a member of the SFRPs family, is associated with cell growth and differentiation in myogenesis. Our previous study suggested that SFRP2 was a potential target of micro RNA(mi RNA)-1/206, which was considered as myomiR s. To further explore the biological function and regulation mechanisms of the SFRP2 gene in porcine skeletal muscle development, we first analyzed the sequence structure of the porcine SFRP2 gene. Subsequently, we detected its tissue distribution in adult Tongcheng pigs(a Chinese indigenous breed) and investigated its dynamic expression in developmental skeletal muscle(13 prenatal and 7 postnatal time points) in Tongcheng pigs. An interaction analysis between SFRP2 and myomi Rs was also performed. The results showed that the expression pattern of the SFRP2 varied greatly across diverse tissues. It exhibited abundant expression in prenatal skeletal muscle and peaked at 55 days post coitus(E55), and had a lower expression in postnatal skeletal muscle, indicating that the SFRP2 gene might affect porcine embryonic skeletal muscle development. Co-expression analysis revealed that the expression levels of SFRP2 correlated negatively with mi RNA-1(r=–0.570, P-value=0.009) and mi RNA-206(r=–0.546, P-value=0.013), but positively with SFRP1(r=0.613, P-value=0.004). The bioinformatics analysis and dual luciferase assay verified that the SFRP2 was a putative target of mi RNA-1/206 in pigs. Therefore, this study is helpful for understanding the biological function and molecular regulation of the SFRP2 gene during porcine skeletal muscle development.     

Metabonomic study of the biochemical profiles of heterozygous myostatin knockout swine

Myostatin is a transforming growth factor-βfamily member that normally acts to limit skeletal muscle growth. Myostatin gene(MSTN) knockout(KO) mice show possible effects for the prevention or treatment of metabolic disorders such as obesity and type 2 diabetes.We applied chromatography and mass spectrometry based metabonomics to assess system-wide metabolic response of heterozygous MSTN KO(MSTN+/–) swine. Most of the metabolic data for MSTN+/–swine were similar to the data for wild type(WT) control swine. There were, however,metabolic changes related to fatty acid metabolism,glucose utilization, lipid metabolism, as well as BCAA catabolism caused by monoallelic MSTN depletion.The statistical analyses suggested that:(1) most metabolic changes were not significant in MSTN+/–swine compared to WT swine;(2) only a few metabolic properties were significantly different between KO and WT swine,especially for lipid metabolism. Significantly, these minor changes were most evident in female KO swine and suggested differences in gender sensitivity to myostatin.     

Effect of MSTN Propeptide and shRNA Co-expression Vector on Proliferation of Skeletal Muscle Satellite Cells

Myostatin(MSTN)is a negative regulator of skeletal muscle growth,in order to study the effect of inhibition MSTN expression on the proliferation of bovine skeletal muscle satellite cells,we constructed co-expression vector pcDNA3.1-ProMSTNshRNA,transfected it into muscle satellite cells by Liposome 2000,and detected cell proliferation changes by CCK-8 method and flow cytometry after 48 h.The expressions of P21 and CDK2 were detected by Western blot and real-time PCR.The results showed that the cell vitality of experimental groups significantly increased than that of the negative control,and cells in S phase also increased significantly(P<0.05).After knocked down MSTN gene,P21 expression decreased(P<0.05),but CDK2 gene expression increased(P<0.05).These results indicated that MSTN gene expression was associated with P21 and CDK2,the proliferation of skeletal muscle satellite cells could be promoted while MSTN was inhibited,which provided a theoretical basis for the study on transgenic cattle.     

Use of transcriptome sequencing to explore the effect of CSRP3 on chicken myoblasts

The mechanisms that regulate the specificity and maintenance of chicken muscle fiber types remain largely unknown. In mammals, CSRP3 has been shown to play a vital role in the maintenance of typical muscle structure and function. This study investigated the role that CSRP3 plays in chicken skeletal muscle. First, the antibody against chicken CSRP3 protein was prepared, and the expression levels of the mRNA and protein of the CSRP3 gene in four chicken skeletal muscles with different myofiber com...     

The genetic diversity analysis in the donkey myostatin gene

Myostatin(MSTN)gene negatively controls skeletal muscle development and growth,variations of which play an important role in the regulation of skeletal muscle growth in mammals.However,study on genetic polymorphism of MSTN gene in donkey is limited.In this study,we screened the single nucleotide polymorphsims(SNPs)of MSTN gene in 13 Chinese donkey breeds.Four novel SNPs(g.229TC,g.872AG,g.2014GA,and g.2395CG)were detected and genotyped by sequencing and polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP)methods.Six haplotypes(H1–H6)were analyzed,which indicated abundant haplotype diversities in Chinese donkeys.The haplotype H1 was the most dominant and ancient in all breeds.Xinjiang donkey displayed the highest haplotype diversity.The Neighbour-Joining(NJ)tree of MSTN gene among different species was constructed.The clustering result of nine species was consistent with the fact of species differentiation.Our results will provide a reliable theoretical basis for the preservation,exploration and utilization of Chinese donkey genetic resources.     

Antizyme 1 Gene is Associated with Loin Muscle Area and Marbling in Landrace × Lantang F2 Resource Population

The expression level of antizyme 1 （AZ1） gene in Longissimus dorsi muscle of Landrace pigs is significantly higher than that of Lantang pigs based on our previous studies. The AZ1 is a key regulator of the concentration of polyamines in cells. It is a good candidate gene for pig＇s performance because polyamines regulate the growth and development of cells. Four PCR-RFLPs were selected to study the relation between AZ1 genotypes and porcine performance. Results showed that the loci of -713 C/T, -584 A/C, and ＋2 432 G/A had significant or highly significant opposite effects on loin muscle area and marbling.     

C-type natriuretic peptide stimulates chicken myoblast differentiation through NPRB/NPRC receptors and metabolism pathway

Skeletal muscle development is closely related with the amount of meat production and its quality in chickens. Natriuretic peptides(NPs) play an important role in myotube formation and fat oxidation of skeletal muscle in animals. The effect of C-type natriuretic peptide(CNP), an important member of the NPs, and its underlying molecular mechanisms in skeletal muscle are incompletely understood. Treatment of myoblasts with CNP led to enhanced proliferation/differentiation and significantly upregul...     

Myofiber development during embryonic to neonatal development in duck breeds differing in muscle growth rates

Little is known about the muscle developmental patterns during embryonic to neonatal development in ducks.We investigated the developmental patterns in the lateral gastrocnemius muscles of Gaoyou and Jinding ducks differing in their muscle growth rates during the final stages of egg incubation and the first week after hatching.Expression of the MyoD gene was quantified by quantitative real-time PCR(qRT-PCR).The average cross-sectional area and diameter of the fibers increased from embryonic day 21(E21),peaking at E27,and then declining slightly 7 d after hatching.The density of the fibers decreased initially but increased after hatching in both breeds and sexes.The within-breed variation in muscle fiber-type composition was greater than the average variation between the breeds.Overall,the percentage of type Ⅰ fibers increased and that of type lIb fibers decreased consistently.However,the percentage of type lla fibers was almost constant as development proceeded in both duck breeds.The profiles of MyoD mRNA expression were similar in both breeds,and a significantly positive relationship was observed between the expression of MyoD and the percentage of type lIb fibers.This study firstly revealed the characteristics of duck muscle development and differences between the two breeds differing in growth rates.Moreover,type lIb fibers might convert to type Ⅰ fibers in the lateral gastrocnemius,while MyoD may potentially function in controlling the muscle fiber phenotype during the secondary myogenesis of muscle development.     

AMPK Subunit Expression Regulates Intramuscular Fat Content and Muscle Fiber Type in Chickens

The objective of this study was to assess the role of AMPK in intramuscular fat(IMF) and fiber type in chicken muscle. The chickens were slaughtered and their muscles were collected at the ages of 4, 8, and 16 weeks so as to determine the IMF contents, as well as the expression levels of AMPK subunits, regulators of adipogenesis. In addition, the myosin heavy chains(My HCs) in thigh muscle tissues were also measured. The results showed that the IMF contents in 16-week old chickens were higher than those in 4 and 8-week-old chickens(P0.05).The expression levels of fatty acid synthase(FAS) and fatty aicd translocase CD36(FAT/CD36) m RNA were increased significantly in samples collected at the ages of4 and 16 weeks(P0.05). The expression levels of My HC IIa and IIb differed significantly among all the developmental stages(P 0.05). The AMPKα2, AMPKγ1,and AMPKγ3 m RNA levels were dramatically decreased with the increase of age(P 0.05). To examine the role of AMPK in adipogenesis regulation, the SV cells were cultured in an adipogenesis medium and treated with AICAR and Compound C respectively, the specific activator and inhibit of AMPK. The Compound C induced dramatically a greater expression of C/EBPβ, SREBP1 and PPARγ(P 0.05). In conclusion, the expression of AMPKα2, AMPKγ1, and AMPKγ3 m RNA is significantly correlated with the adipogenesis in skeletal muscle of chickens.     

Determining nitrogen status and quantifying nitrogen fertilizer requirement using a critical nitrogen dilution curve for hybrid indica rice under mechanical pot-seedling transplanting pattern

Field experiments of nitrogen(N) treatment at five different application rates(0, 75, 150, 225, and 300 kg ha~(-1)) were conducted under pot-seedling mechanical transplanting(PMT) in 2018 and 2019. Two high-quality and high-yielding hybrids of indica rice, Huiliangyou 898 and Y Liangyou 900, were used in this study. The N nutrition index(NNI) and accumulated N deficit(N_(and)), used to assess the N nutrition status in real-time, were calculated for the indica cultivars under PMT with a critical nitrogen concentration(N_c) dilution model based on shoot dry matter(DM) during the whole rice growth stage. The relationships between NNI and N_(and) with relative yield(RY) were determined, and accurate N application schemes were developed for hybrids indica rice under PMT. The results indicated that high application rate of N-fertilizer significantly increased the concentrations of shoot DM and N in aboveground organs during the observed stages in the two cultivars for two years(P0.05). The N_c dilution model of hybrid indica cultivars was N_c=4.02 DM~(-0.42)(R~2=0.97) combining the two cultivars under PMT. Root-mean-square error and normalized root-mean-square error of the curve verification were 0.23 and 10.61%, respectively. The NNI and N_(and) ranged from 0.58 to 1.31 and 109 to –55 kg ha~(-1), respectively, in the two cultivars for all N treatments. NNI showed a linear relationship with N_(and) during the entire growth stage(0.53R~20.99, P0.01). In addition, NNI showed a linear-plateau relationship with RY(0.73R~20.92, P0.01) throughout the observed stages. These results suggest that the models can accurately diagnose the N-nutrition status and support effective N-fertilizer management in real-time for hybrid indica rice under PMT.     

海南岛橡胶林土壤真菌群落多样性的季节变化特征及其驱动因子分析

探究海南岛橡胶林土壤真菌群落多样性的季节变化特征及其环境驱动因子,为天然橡胶产业的可持续发展提供科学依据。以海南岛橡胶林旱季和雨季的土壤真菌为研究对象,使用Illumina Miseq高通量测序法,对土壤真菌的α、β多样性和群落结构组成及与环境因子的关系进行分析。结果表明,1)海南岛橡胶林共检测到真菌9门、37纲、115目、289科、818属,优势菌门依次为子囊菌门(Ascomycota)、担子菌门(Basidiomycota)和接合菌门(Zygomycota);2)橡胶林土壤真菌雨季土壤真菌丰富度和多样性均高于旱季,基于 Bray-Curtis距离的PCoA分析,不同季节土壤真菌群落β多样性差异显著(ANOSIM:R=0.051,P=0.001),PERMANOVA分析结果表明,季节变化解释了真菌群落组成差异的1.7%(R²= 0.017,P=0.001);3)真菌α多样性与pH(R²=0.19,P<0.001)、温度(R²=0.14,P<0.001)、全N(TN:R²=0.13,P<0.001)呈显著正相关。温度、全N、有机质、降雨量和pH分别解释了真菌群落组成的8.90%、5.42%、4.73%、4.32%、4.29%。橡胶林土壤真菌群落存在显著的旱雨季变化,pH、温度、全N是影响土壤真菌群落多样性的主要环境因子。     

不同红树植物叶片元素重吸收特征

为明确不同红树植物养分重吸收状况,以福建漳江口拒盐红树秋茄和木榄、泌盐红树白骨壤和桐花树为对象,测定成熟叶和衰老叶中N、P、K、Ca、Mg、Fe、Mn、Cu、Zn含量。结果表明,4种红树植物成熟叶（Zn除外）、衰老叶（Cu除外）养分含量差异显著（P<0.05）,衰老叶N、P、K、Cu、Zn含量均低于成熟叶,为正转移,平均转移率分别为65.88%、38.35%、44.27%、35.78%和66.91%;衰老叶Mg、Fe、Mn（木榄除外）含量高于成熟叶,为负转移,平均转移率分别为-120.56%、-45.93%和-30.25%。泌盐红树（白骨壤和桐花树）N和P重吸收效率显著低于拒盐红树（秋茄和木榄）（P<0.05）,而泌盐红树的K重吸收效率显著最高（P<0.05）。不同红树植物养分重吸收效率与其成熟叶养分含量呈正相关关系（Mg除外）,与其衰老叶均呈负相关关系。综上可知,不同红树植物对不同养分的重吸收具有特异性,秋茄和木榄通过较高的N、P重吸收效率适应滨海的特殊生境,而白骨壤和桐花树则通过提高凋落物的N、P、Mg、Cu、Zn输入,对土壤养分的有效性作出正反馈。     

雪峰乌骨鸡HSP70基因多态性与精液品质关联分析

旨在研究雪峰乌骨鸡HSP70基因多态性及其与鸡冻精品质的关系,以期筛选出鸡精液抗冻性相关分子标记,为鸡精液冷冻保存及其分子育种提供技术支撑。选取100只同一批次、性成熟的白羽雪峰乌骨种公鸡,测定采精量、精子密度和冻精活力等指标。翅静脉采血,提取基因组DNA并扩增HSP70基因,构建精液品质低、中、高3个混池并测序。单个样本测序后,比对测序峰图,完成基因分型,统计不同基因型个体数,并进一步进行精液品质关联分析。结果发现:HSP70基因436 bp处存在G>A突变,G为优势基因,将群体分成AA、AG和GG这3种基因型,各基因型频率依次为22%、44%和34%,该位点遗传多样性分析PIC=0.371 4,为中度多态位点,Hardy-Weinberg平衡适合性检验得χ²=1.148 0(P>0.05),该群体符合Hardy-Weinberg平衡规律。基因多态与精液品质关联分析表明,GG基因型个体采精量和精子密度极显著(P<0.01)高于AG型、AA型个体,且冻后活力显著(P<0.05)高于AG型个体,极显著(P<0.01)高于AA型个体;AG型个体采精量和精子密度极显著(P<0.01)高于AA型个体,冻精活力差异不显著(P>0.05)。综上所述,HSP70基因突变G/A位点与鸡冻精品质显著相关,可以作为雪峰乌骨鸡个体精液抗冻性的候选基因,基因型GG的个体精液更具抗冻性,其次为AG型个体。     

6个紫薇品种叶片色彩变化及其与色素含量的相关性

探究6个紫薇品种不同试验阶段的叶片色素变化规律,以“紫精灵、红火箭、紫莹、赤红、丹红、玲珑红”6个紫薇品种为实验材料,比较不同时期紫薇叶片的色彩参数L^*、a^*、b^*值以及叶绿素 a、叶绿素 b、类胡萝卜素质量分数和花色素苷含量。结果表明,紫薇叶片明度（L^* ）值变化不大,而红度（a^* ）、黄度（b^* ）值变化明显。‘紫莹’‘丹红’‘赤红’3个紫叶紫薇品种的a^*显著降低（P＜0.05）,‘玲珑红’a^*值呈升高趋势。b^*值在绿叶紫薇品种中呈显著性升高（P＜0.05）,在紫叶紫薇品种中无显著性变化。随着试验阶段的变化,‘紫精灵’‘红火箭’‘玲珑红’绿叶紫薇品种叶片叶绿素含量（质量分数,下同）逐渐升高,花色素苷含量逐渐降低,并且叶绿素含量始终高于其他色素含量,‘紫莹’‘丹红’‘赤红’则相反。在叶片色彩参数与色素含量的相关性分析中结果表明:‘紫莹’‘丹红’‘赤红’的花色素苷含量与叶片a^*呈显著或极显著正相关,类胡萝卜素含量与叶片b^*呈显著正相关。     

基于立地因子及其交互作用的柠条生物量模型研究

森林碳汇是实现碳中和目标的重要路径之一，精确计算森林碳储量具有十分重要的意义。生物量模型是估测森林生物量、计算森林碳储量的重要手段。以宁夏白芨滩林场的典型灌木树种柠条为研究对象，通过样地调查及样本采集，利用非参数双因素方差分析坡向、坡度2个立地因子及其交互作用对柠条各类(总、地上、茎、叶、根)生物量的影响，并基于哑变量模型，构建了立地因子及其交互作用的生物量模型。结果表明，除坡向与坡度的交互作用对柠条叶生物量影响不显著外(P=0.399)，坡向、坡度及其交互作用对柠条其余各类生物量影响均显著(P<0.01)；在柠条各类生物量模型中，以总基径(D)平方和与平均高(H)的乘积(D_t²H)为自变量、以f_i(x)=a+bx_i为基本形式建立的生物量模型拟合精度较高(总、地上、茎、叶、根生物量模型的adj-R²分别为0.645 2、0.671 0、0.623 2、0.600 0、0.502 0)；以坡向、坡度及其交互作用作为哑变量能够显著提高模型的预估能力，其中，对于叶生物量，以坡度...     

性成熟前期尼罗罗非鱼雌雄性别生长差异与性类固醇激素水平比较

利用分子标记法、醋酸洋红压片法、组织切片技术等方法进行个体性别鉴定,比较了性成熟前期(0.5~4.0月龄)尼罗罗非鱼雌、雄鱼生长差异,并检测了2.5~4.0月龄雌、雄鱼血清睾酮(T)、雌二醇(E₂)激素含量。结果发现,雌、雄鱼全长、体质量分别自3.0月龄、2.5月龄开始出现差异显著(P<0.05)。Logistic拟合全长、体质量生长方程为:L_t(♀)=16.443/(1+e^{(2.821-1.363*t)}),L_t(♂)=18.248/(1+e^{(2.752-1.295*t)});W_t(♀)=107.704/(1+e^{(5.157-1.464*t)}),W_t(♂)=134.796/(1+e^{(5.080-1.417*t)}),雌、雄鱼体质量生长拐点分别为3.523、3.585月龄,拐点体质量分别为52.352、67.398 g。雄鱼全长、体质量生长速度始终大于雌鱼,雄鱼快速增长期区间长度、体质量增加量大于雌鱼。2.5月龄之后,雌、雄鱼E₂含量差异显著(P<0.05),3.0月龄之后,雌、雄鱼T含量差异显著(P<0.05),推测E₂、T含量差异是引起尼罗罗非鱼雌雄性别生长差异的原因之一。     

丹波黑大豆GmDREPP基因的克隆与耐铝性

发育调节质膜多肽(developmentally-regulated plasma membrane polypeptide, DREPP)是一类植物特异性蛋白,参与植物对生物和非生物胁迫的响应与调控。本研究以耐铝丹波黑大豆(Glycine max cv. Tamba)为试验材料,克隆获得编码丹波黑大豆GmDREPP蛋白基因的CDS序列,构建组成型过表达载体pCXSN-GmDREPP,成功遗传转化烟草(Nicotiana tabacum),并运用qRT-PCR定量技术研究GmDREPP基因在丹波黑大豆中的表达情况。结果表明,铝胁迫下GmDREPP在丹波黑大豆的根、茎、叶、子叶中均有表达,根中又以根尖的表达量最高;GmDREPP的根尖表达水平随Al³⁺浓度增加而上升,Al³⁺浓度高于50μmol·L^-1后其表达量无显著变化。对转基因烟草阳性植株进行RT-PCR分析,选取3个表达水平较高的转基因株系(GmDREPP-2、GmDREPP-4、GmDREPP-5)进行耐铝性分析,结果表明:(1)50μmol·L^-1     

肌纤维类型组成对猪肌肉品质与能量代谢的影响研究进展

肌纤维是肌肉组织的基本结构单位,通过改变肌纤维类型组成提高肌肉品质是当前的研究热点之一.成年哺乳动物骨骼肌肌纤维类型按肌球蛋白重链基因(MyHC)的多态性表达可分为Ⅰ、2a、2x、2b型4种类型,Ⅰ、2a型属偏氧化型肌纤维,2x、2b型属偏酵解型肌纤维.动物出生前,肌纤维MyHC异构体一般表达为胚胎型、胎儿型、Ⅰ和2a...     

Quantification and prediction of enteric methane emissions from Chinese lactating Holstein dairy cows fed diets with different dietary neutral detergent fiber/non-fibrous carbohydrate (NDF/NFC) ratios

Methane(CH₄) emissions from ruminant production are a significant source of anthropogenic greenhouse gas production, but few studies have examined the enteric CH₄ emissions of lactating dairy cows under different feeding regimes in China. This study aimed to investigate the influence of different dietary neutral detergent fiber/non-fibrous carbohydrate(NDF/NFC) ratios on production performance, nutrient digestibility, and CH₄ emissions for Holstein dairy cows at ...