网渔具计算机数值模拟的研究进展

对近年来网渔具的计算机数值模拟中使用的几何拓扑分解方法、数学建模思想和模型算法等进行了归纳和系统整理,并探讨了各种算法的稳定性和收敛性。分析认为:刚体有限元法数学建模的优点是模型简化,能基本反映网具粗糙形状,缺点是忽略网线张力,无法精确反映网具的受力和网具的运动状态;基于质量弹簧体系和牛顿力学的柔性有限元法是主流,数值模拟结果更符合网具的实际状况,网形更细腻逼真,计算结果与网具实测拟合较好;显式算法对时间步长较敏感,稳定性和精度不如隐式算法好。NEWTON-RAPHSON和NEWMARK-β算法具有无条件稳定性和收敛性,大部分研究采用了此算法。     

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.     

Efficacy of 17 α‐methyl testosterone and letrozole on sex reversal of protogynous grouper,Epinephelus tauvina (Forskal, 1775) and spawning performance of sex‐reversed males

This study aimed to test the efficacy of 17 α‐methyl testosterone (17 α‐MT) alone and in combination with letrozole, an aromatase inhibitor, for the induction of sex reversal in protogynous greasy grouper, Epinephelus tauvina. Further, the long‐lasting effects of these treatments and spawning performance of sex‐reversed males were also investigated. Greasy grouper with oocytes in the perinucleolus stage were implanted with 5 mg 17 α‐MT kg^?1 body weight (T₁), 5 mg 17 α‐MT and 0.2 mg letrozole kg^?1 body weight (T₂) and 5 mg 17 α‐MT with 0.4 mg letrozole kg^?1 body weight (T₃) and no androgens/enzyme inhibitor implanted (C). The 17 α‐MT alone and in combination of letrozole‐induced sex reversal in greasy grouper, whereas untreated control fish (C) showed normal ovarian development. However, T₂ and T₃ group showed 100% sex reversal and completion of spermatogenesis up to functional male phase in 2 and 3 months, respectively, whereas T₁ group resulted in only 66.67% functional male with motile spermatozoa after 4 months. Sex‐reversed males successfully fertilized the eggs during induced spawning. There were significant differences on fertilization and hatching rates between T₂ group (79.00 ± 4.36%; 77.67 ± 2.87%, respectively) and T₁ group (57.67 ± 3.17%; 63.87 ± 2.91%, respectively). The result suggested that 17 α‐MT (5.0 mg kg^?1 BW) in combination with letrozole (0.2 mg kg^?1 BW) has the potential to produce 100% sex‐reversed male in short period in greasy grouper, which might greatly help in seed production of greasy grouper.     

黏虫体内两种微管蛋白基因cDNA序列的克隆与序列分析

以黏虫4龄幼虫为材料提取总RNA,利用RT-PCR和cDNA末端快速扩增技术(RACE),分别扩增得到该虫的α和β微管蛋白基因的cDNA序列各1条。其中α微管蛋白基因的cDNA序列1 443个碱基,包括一个1 353个碱基的开放阅读框,编码一个含450个氨基酸的蛋白,分子量约为50.0ku。氨基酸的142~148位存在一个微管蛋白标志信号片段GGGTGSG,在氨基酸序列的C-端有一个酪氨酸残基,N-端存在一个对转录后调控非常重要的保守区MRECI序列,以上特点与其他昆虫α微管蛋白氨基酸序列相同。黏虫β微管蛋白基因cDNA序列含1 906个碱基,开放读码框1 344个碱基,编码氨基酸447个,分子量约为50.2ku,等电点4.75。1~4个氨基酸MREI为β微管蛋白转录后调控信号,140~146GGGTGSG位同样存在一个微管蛋白标志信号片段。序列比对表明,克隆的α和β微管蛋白基因与其他昆虫的α和β微管蛋白基因在核苷酸和氨基酸水平上都是高度同源的,黏虫与家蚕(Bombyx mori)α微管蛋白的氨基酸序列同源性达到99.3%,与其他3种夜蛾科昆虫α微管蛋白的氨基酸序列同源性更是达到100%。黏虫与家蚕β微管蛋白的氨基酸序列同源性达到98.7%,与烟草天蛾β微管蛋白的氨基酸序列同源性达到99.6%。两个基因的cDNA序列已经登录GenBank并获得登录号分别为EU100016和EU234504。     

17β-Estradiol Regulates SKP2 Expression in Cultured Immature Boar Sertoli Cells Mainly via Estrogen Receptor β, cAMP-PKA and ERK1/2

Estrogen plays an important role in regulating testicular Sertoli cell number. Furthermore, S-phase kinase-associated protein 2 （SKP2） plays a central role in mammalian cell cycle progression. The objective of this study was to determine whether 17β-estradiol can regulate the expression of SKP2, and the Sertoli cell cycle, via estrogen receptor β （ERβ）, the cyclic adenosine monophosphate （cAMP）-protein kinase A （PKA） and extracellular signal-regulated kinase （ERK1/2） pathway. When cultured immature boar Sertoli cells were treated with 17β-estradiol, a time-dependent increase in SKP2 mRNA and protein level was observed by real-time PCR and Western blot, and 17β-estradiol activity peaked at 30 min. Treatment with ICI182780 and ERβ antagonist reduced 17β-estradiol-induced expression of SKP2 and proliferating cell nuclear antigen （PCNA）, while increasing the protein concentration of p27kip1. However, the effect of ERa antagonist on these parameters was lower than that of ICI 182780 and ERβ. Forskolin had a similar effect as 17β-estradiol on the expression of SKP2, PCNA and p27kip1, Rp-cAMP, H-89 and U0126 treatment reduced 17β-estradiol-induced changes, while H-89 also inhibited ERK1/2 activation. Therefore, 17β-estradiol mainly regulates SKP2 mRNA and protein expression via ERβ-cAMP-PKA and ERK1/2 activation. SKP2 and PCNA expression were positively correlated, while increased SKP2 expression likely resulted in p27kip1 degradation.     

雌激素胁迫对萝卜种子萌芽和幼苗生长及其累积效应的影响

通过水培试验,研究了不同浓度17β-雌二醇(17β-E2)胁迫对萝卜种子萌芽、幼苗生长和抗氧化酶系统活性的影响,以及17β-E2在幼苗体内的积累。结果发现,萝卜种子的发芽势、发芽率和根长与17β-E2处理浓度呈负相关,在10 μg/L浓度时17β-E2刺激萝卜种子的发芽势和根长明显增加,诱导幼苗体内抗氧化酶SOD、POD和CAT活性显著上升;但在50 μg/L浓度的17β-E2胁迫下,SOD、CAT和POD活性受到明显抑制,MDA含量显著升高,幼苗抗氧化能力显著降低,膜质过氧化程度加剧;受17β-E2污染,萝卜幼苗体内17β-E2积累量随着处理浓度的升高而增加,其在根部累积量要大于地上部分,在转运过程中发生17β-E2代谢,产生具有低雌激素活性的雌酮。萝卜对17β-E2胁迫具有一定的抗性,在17β-E2污染土壤中种植萝卜存在潜在的食用安全风险。     

IL-17细胞因子家族调节黏膜免疫的研究进展

皮肤和黏膜上皮细胞既是机体的物理屏障,又是机体防御微生物的第一道防线。上皮细胞与白细胞、树突细胞(DCs)等之间的相互作用,是机体产生适应性免疫反应的重要因素。IL-17细胞因子家族是最近新发现的具有强大的促炎症作用的细胞因子,它们在机体的固有和适应性免疫中发挥着重要作用,IL-17A、IL-17C和IL-17F能够直接作用于组织的上皮细胞,诱导各种免疫反应来对抗病原体,且能够促进组织的修复。IL-17E最基本的作用是作用于白细胞和诱导Ⅱ型免疫,这在其对抗寄生虫的作用中是非常关键的,此外,IL-17E还可以反向调节白细胞对IL-17A和IL-17F的产生;而对于IL-17B和IL-17D的研究则相对较少一些。     

ER及其相关基因在鸡性反转胚胎中的表达

为了对鸟类性别分化中起重要作用的基因进行深入分析,对家鸡性反转胚胎雌激素及相关调控基因表达模式进行了检测,分析这些性激素在鸟类性别分化调控起到的作用。选择ER、3βHSD、P450c17、P450arom 4个基因为主要研究对象,采用外源注入formestane（福美司坦）和17β-estradiol（17β雌二醇）2种手段,并设置雌雄鸡胚2个对照组,检测以上基因在胚胎早期发育过程中(84 h、96 h、120 h、144 h、168 h、192 h)的表达变化趋势。ER、3βHSD、P450c17、P450arom基因的表达变化在注入外源激素的试验组同未注射组间,差异均显著(P＜0.05)或极显著(P＜0.01),其中ER表现为下降趋势,P450arom表达激增,3βHSD、P450c17基因表达变化缺乏明显规律。雌激素调控是一个复杂的过程,在外源激素注入过程后,原有调控模式可能会被打乱。     

文昌鸡促卵泡激素β基因内含子1的SNP分析及其与早期产蛋性能的相关性研究

以109只海南文昌鸡为试验动物,利用PCR-SSCP技术检测了促卵泡激素(follicle-stimulating hormone β,FSHβ)基因的多态性,在其内含子1区域内发现了1个SNP,在群体中检测出2种基因型:AA、AB。将不同基因型个体与产蛋数、畸形蛋数、体重和开产日龄等进行了关联分析。结果表明,AA基因型鸡个体的产蛋数比AB基因型个体多9.54枚,畸形蛋数比AB基因型个体少1.54枚,开产日龄比AB基因型个体早2.97 d,且差异均不显著(P＞0.05)。22~26、27~30和31~34周龄的AA基因型鸡的产蛋量显著高于AB基因型(P＜0.05),而18~21和35~39周龄的AA基因型鸡的产蛋量也明显高于AB基因型,但差异不显著(P＞0.05)。AA基因型鸡6、8、14、20周龄的体重高于AB基因型个体,AA基因型个体18周龄的体重却低于AB基因型个体,差异均不显著(P＞0.05)。总体而言,FSHβ基因位点的A等位基因对产蛋数、畸形蛋数、体重和开产日龄的影响均未达到差异显著水平。     

卵泡刺激素β基因编码区SNPs与糯谷猪繁殖性能的关联性分析

本试验采用RCR-SSCP及测序的方法检测了58头糯谷猪母猪卵泡刺激素(follicle-stimulating hormone,FSH) β基因编码区3个外显子的多态性,并分析了不同基因型与繁殖性能的关联性,结果发现,在外显子1和外显子3中未发现多态位点,外显子2中发现了2个新的多态位点,共检测出3个等位基因,5个基因型,未检测到BB基因型。其中A等位基因在6699位点发生了C→T突变,B等位基因在6708位点发生了T→C突变,C等位基因与公布序列一致,A、B、C等位基因频率分别为0.288、0.119、0.593。2个突变均为同义突变,各基因型间的繁殖性能差异不显著。