微塑料对双酚A在鲤鱼肠道中累积及生长生理的影响

探明微塑料（MPs）对双酚A （BPA）在鱼类肠道中累积特征及鱼类生长生理的影响,本研究以黄河鲤鱼为模型生物,分析了0.5 μm聚苯乙烯微塑料（PS-MPs）与BPA联合作用下鲤鱼肠道中微塑料及BPA的累积特征、鲤鱼生长及其抗氧化酶活性,以及它们之间的响应关系。结果表明：联合处理下鲤鱼肠道中的PS-MPs含量随时间呈线性增加,且随投加的微塑料浓度增加而增加,而PS-MPs累积速率随时间呈先增加后减小趋势,其中在BPA+PS（L）处理（1 mg·L^-1 BPA+20 μg·L^-1 PS-MPs）下,0.25 d时鲤鱼肠道中PS-MPs累积速率达到峰值（373.81 μg·g^-1·d^-1）,BPA+PS（H）处理（1 mg·L^-1 BPA+100 μg·L^-1 PS-MPs）下,则是在0.125 d达到最高（644.00 μg·g^-1·d^-1）。与单一BPA暴露相比,联合暴露下鲤鱼肠道中BPA累积量增加,与BPA （1 mg·L^-1 BPA）处理相比,BPA+PS （L）和BPA+PS （H）处理下鲤鱼肠道中BPA含量分别提高了6.13%和9.74%,BPA累积速率分别增加了190.01%、373.80%。相较于对照处理,BPA处理和MPs与BPA联合处理均引起鲤鱼肠组织中超氧化物歧化酶（SOD）活性、过氧化氢酶（CAT）活性、还原型谷胱甘肽（GSH）含量、丙二醛（MDA）含量增加,使体质量下降幅度减缓,其中BPA、BPA+PS （L）和BPA+PS （H）处理下鲤鱼体质量（21 d）较对照处理分别下降1.22%、3.90%、4.33%。当微塑料投加量达到100 μg·mL^-1时,联合处理会增加鲤鱼肠道中SOD活性、CAT活性和GSH含量,抑制MDA产生,从而缓解MPs和BPA联合作用对鲤鱼造成的氧化损伤,并且减缓鲤鱼体质量下降。研究表明,微塑料的存在会增加双酚A在鲤鱼肠道中的累积,且两者联合作用对鲤鱼产生了协同毒理效应,导致鲤鱼生长速率减缓,体质量下降。     

四种不同食性鱼类肠道微生物群落组成及多样性比较分析

本研究旨在探讨食性对鱼类肠道菌群组成和多样性的影响,并预测特定菌群对不同营养素的潜在功能。实验采用高通量16S rRNA基因测序技术,提取获得滇池高背鲫(Carassius auratus)、草鱼(Ctenopharyngodon idellus)、鳜鱼(Siniperca chuatsi)、昆明裂腹鱼(Shizothorax grahami) 4种不同食性鱼类的肠道内容物,12个样品的16S rRNA,构建文库并测序,分析这4种鱼类肠道微生物的菌落组成和多样性。结果显示,鱼类肠道菌群多样性受到食性的显著影响(P<0.05),综合表现为杂食性(滇池高倍鲫) > 草食性(草鱼) > 滤食性(昆明裂腹鱼) > 肉食性(鳜鱼)。4种鱼类具有一些相同的优势菌群：变形菌门(Proteobacteria)和厚壁菌门(Firmicutes)。然而,优势菌群在属水平上存在一定差异,如不动杆菌属(Acinetobacter)为鳜鱼的优势菌群,拟杆菌属(Bacteroides)为草鱼的优势菌群等。功能预测发现,鳜鱼肠道中以革兰氏阴性菌为主;草鱼抗病潜力略高于其他3种鱼类;约氏不动杆菌(A._ johnsonii)、鲁氏不动杆菌(A. lwoffii)和施氏假单胞菌(Pseudomonas stutzeri)可能有助于宿主对蛋白质的消化,而拟杆菌属中的某些菌群可能有助于宿主消化纤维素。综上所述,食性是影响鱼类肠道菌群组成和多样性差异化的主要因素之一,分析食性与肠道优势菌群之间的关联,探讨特异菌群的功能,可为研究鱼类营养代谢的微生物效应奠定理论基础。     

β-Carotene from the Alga Dunaliella bardawil Decreases Gene Expression of Adipose Tissue Macrophage Recruitment Markers and Plasma Lipid Concentrations in Mice Fed a High-Fat Diet

Vitamin A and provitamin A carotenoids are involved in the regulation of adipose tissue metabolism and inflammation. We examined the effect of dietary supplementation using all-trans and 9-cis β-carotene-rich Dunaliella bardawil alga as the sole source of vitamin A on obesity-associated comorbidities and adipose tissue dysfunction in a diet-induced obesity mouse model. Three-week-old male mice (C57BL/6) were randomly allocated into two groups and fed a high-fat, vitamin A-deficient diet supplemented with either vitamin A (HFD) or β-carotene (BC) (HFD-BC). Vitamin A levels in the liver, WATs, and BAT of the HFD-BC group were 1.5–2.4-fold higher than of the HFD group. BC concentrations were 5–6-fold greater in BAT compared to WAT in the HFD-BC group. The eWAT mRNA levels of the Mcp-1 and Cd68 were 1.6- and 2.1-fold lower, respectively, and the plasma cholesterol and triglyceride concentrations were 30% and 28% lower in the HFD-BC group compared with the HFD group. Dietary BC can be the exclusive vitamin A source in mice fed a high-fat diet, as shown by the vitamin A concentration in the plasma and tissues. Feeding BC rather than vitamin A reduces adipose tissue macrophage recruitment markers and plasma lipid concentrations.     

砂轮约束磨粒喷射精密光整加工有效性实验验证

通过实验验证了砂轮约束磨粒喷射精密光整加工方法的有效性,利用M7120平面磨床对Q235A进行了喷射加工实验,用TALYSURF5轮廓仪测量了加工后的微观几何参数值,用扫描电镜和金相显微镜观察了表面微观形貌和断面金相组织变化。实验结果表明,该加工方法在表面粗糙度得到减小的同时,能明显去除磨削加工过度塑性变形,减少表面层污染和磨削烧伤,改善表面形状精度,实验结果和理论分析吻合,验证了该工艺方法的正确性。     

福建柏愈伤组织诱导与抗褐化研究

【目的】比较不同抗褐化剂减轻福建柏组织培养过程中褐化现象的效果,以提高福建柏愈伤组织培养的增殖分化能力。【方法】以福建柏鳞叶和茎段为外植体,通过单因素试验,研究0.0～2.5 mg/L NAA和2,4 D及0.0～3.0 mg/L IBA对愈伤组织诱导率与生长状态的影响;以福建柏茎段为外植体,采用单因素和多因素组合试验,研究100～2 000 mg/L聚乙烯吡咯烷酮（PVPP）、100～1 000 mg/L活性炭（AC）和V_C以及不同质量浓度VC与AC组合,对愈伤组织污染率、死亡或褐化率及诱导率的影响;以诱导的愈伤组织为材料,采用单因素试验,研究100～1 000 mg/L PVPP、100～300 mg/L V_C、200～1 000 mg/L AC、30～100 mg/L V_B对愈伤组织增殖生长量、增殖率、褐化率及PPO、POD活性的影响。【结果】① 不同质量浓度NAA、2,4-D和IBA对福建柏鳞叶愈伤组织的诱导率总体高于茎段,各生长素对福建柏鳞叶和茎段愈伤组织的诱导率均表现为NAA＞IBA＞2,4-D,所有处理中以1.0 mg/L NAA对福建柏鳞叶愈伤组织的诱导率最高,为83.33%;以0.5 mg/L NAA对茎段愈伤组织的诱导率最高,为61.11%;愈伤组织生长状态和抗褐化效果优劣依次为NAA、2,4-D、IBA。②仅100 mg/L V_C+200 mg/L AC处理的愈伤组织污染率低于不添加抗褐化剂的对照;死亡或褐化率仅500 mg/L PVPP处理与对照相同,均为0.00%,其余处理均高于对照;诱导率则以不同质量浓度PVPP、1 000 mg/L VC、100 mg/L V_C＋200 mg/L AC处理与对照相当或高于对照,其余处理均低于对照;愈伤组织生长状态总体以PVPP处理表现最优。③仅300 mg/L PVPP、200和400 mg/L AC处理的愈伤组织增殖率高于对照,增殖生长量仅100和200 mg/L PVPP、100 mg/L V_C、200 mg/L AC处理高于对照;所有处理中以200 mg/L AC处理的愈伤组织增殖率和增殖生长量最高,分别为70.00%和10.07 g;各抗褐化剂对福建柏愈伤组织增殖效果的优劣依次为PVPP、AC、V_C、V_B。④不同抗褐化剂处理的愈伤组织褐变率均呈先增加后趋于稳定的变化趋势,但变化幅度存在显著差异;各抗褐化剂的抗褐化效果优劣依次为AC、PVPP、V_C、V_B。⑤不同质量浓度PVPP、V_C、AC处理对福建柏愈伤组织PPO和POD活性的影响具有显著差异,但各处理PPO活性均与对照无显著差异,POD活性以500 mg/L AC处理显著高于其他处理。【结论】在福建柏愈伤组织诱导阶段,愈伤组织的褐化与生长素种类有关,生长素NAA、2,4-D适用于福建柏愈伤组织的诱导,IBA诱导的愈伤组织容易褐化,添加适量抗褐化剂能减少愈伤组织的褐化情况。在愈伤组织增殖培养阶段,适宜质量浓度的PVPP、AC作为抗褐化剂能有效减缓福建柏愈伤组织的褐化进程,保持愈伤组织的正常增殖生长,但高质量浓度的抗褐化剂会抑制愈伤组织的生长。     

丛枝菌根真菌对元宝枫生长及其根系形态的影响

【目的】阐明丛枝菌根（arbuscular mycorrhizal,AM）真菌对元宝枫生长状况及根系形态特性的影响,探讨元宝枫根系形态与其生长发育的关系。【方法】在元宝枫幼苗生长基质中接种摩西斗管囊霉（Funneliformis mosseae）和根内根孢囊霉（Rhizophagus intraradices）2种AM真菌,以不接种AM真菌为对照,通过盆栽试验,培养90 d后,测定元宝枫的生长状况、根系活力及根系形态指标,利用单因素方差分析和多重比较方法,分析接菌与不接菌处理之间的差异,采用envfit ()函数、冗余度分析和变差分解分析元宝枫生长状况与其他指标间的关系。【结果】①接种2种AM真菌后,元宝枫株高、地径、茎干质量和根系活力较对照显著提高,根冠比下降。根内根孢囊霉对元宝枫的促生作用比摩西斗管囊霉显著。②与对照相比,接种2种AM真菌后,元宝枫根表面积和根体积显著增大,粗根根长占总根长的比例增加,细根根长占总根长的比例显著降低。根内根孢囊霉对元宝枫根系形态的影响比摩西斗管囊霉显著。③元宝枫生长状况与其根系活力和根系形态密切相关。【结论】接种AM真菌有助于增强元宝枫的根系活力,改善其根系形态,促使其汲取更多养分,进而提高其生物量。     

瓠瓜KNOX基因家族全基因组鉴定及组织表达分析

【目的】 探明瓠瓜KNOX基因家族特征,在瓠瓜全基因组水平上对KNOX基因家族成员进行鉴定和分析,研究其组织表达模式。【方法】利用生物信息学方法,对瓠瓜KNOX家族基因成员进行鉴定、编码蛋白理化性质分析及家族成员结构域和保守基序分析,利用MEGA 5.05软件构建系统进化树,采用实时荧光定量PCR技术,分析KNOX基因在瓠瓜不同组织（根、茎、叶、花、果实）中的表达情况。【结果】鉴定到12个瓠瓜KNOX家族基因,这些基因分布在6条染色体上,且均定位于细胞核。大多数瓠瓜KNOX家族蛋白含有同源异型盒蛋白特有的4种结构域KNOX1、KNOX2、ELK 和Homeobox_KN。系统进化分析将瓠瓜KNOX基因分为KNOX Class Ⅰ和KNOX Class Ⅱ 2大类群,2个类群又可进一步分为5个分支,其中Class Ⅰ-C为瓠瓜特有的进化分支。KNOX基因启动子区有多个激素响应元件和植物生长相关元件。组织表达分析发现,瓠瓜KNOX基因具有不同的表达模式,KNOX Class Ⅰ类基因表达具有组织特异性,在根、茎和果实中表达量较高,在其余组织中表达量较低或不表达,其中Lsi04G014450在根和茎中表达量最高,Lsi11G006380在果实中表达量最高;KNOX Class Ⅱ类基因在所有组织中均有较高表达。【结论】瓠瓜KNOX基因家族有12个成员,分布于6条染色体上,在进化关系上可分为5组,具有瓠瓜特有的进化分支,在不同组织中的表达具有特异性。     

草地贪夜蛾核型多角体病毒对草地贪夜蛾的毒力及其侵染特征

为明确草地贪夜蛾核型多角体病毒（Spodoptera frugiperda multiple nucleopolyhedrovirus,SfMNPV）对草地贪夜蛾Spodoptera frugiperda 的毒力及其体内外侵染特性,于室内测定SfMNPV对草地贪夜蛾的毒力,采用苏木精-伊红（hematoxylin-eosin,HE）染色分析SfMNPV侵染后草地贪夜蛾的组织病理学特征,通过实时荧光定量PCR（real-time fluorescence quantitative PCR,qPCR）技术分析SfMNPV在草地贪夜蛾体内和Sf9细胞系中的复制特征。结果表明,SfMNPV对草地贪夜蛾2龄幼虫的LC₅₀和LT₅₀分别为7.39×10⁵ OBs/mL和3.82 d;SfMNPV可侵染草地贪夜蛾幼虫的真皮、气管、脂肪体和中肠等组织,未侵染肌肉组织;SfMNPV侵染96 h后草地贪夜蛾体内SfMNPV基因组拷贝数最大,为3.91×10⁶ 拷贝数/ng,SfMNPV侵染96 h后Sf9细胞培养上清液中SfMNPV基因组拷贝数最大,为2.08×10⁷ 拷贝数/mL。     

Tissue-specific antioxidative and neurotoxic responses to diazinon in Oreochromis niloticus

The purpose of this study was to evaluate oxidative stress and neurotoxic potential of organophosphorus (OP) insecticide diazinon in the sentinel freshwater fish, Oreochromis niloticus. Antioxidant and acetylcholinesterase (AChE) enzyme activities and malondialdehyde (MDA) and protein levels were measured spectrophotometrically in gill, kidney, alimentary tract, and muscle tissues of fish treated with sub-lethal diazinon concentrations for 1, 7, 15, and 30 days. Dose-dependent inhibitions of AChE were observed in all the experimental fish. On the contrary of alimentary tract, MDA levels were elevated in kidney and muscle and gill was not affected. AChE and MDA levels intercorrelated in kidney and muscle tissues. Diazinon had increased superoxide dismutase (SOD) activities in all the tissues, while kidney was the most affected tissue. Tissue-specific alterations were observed on catalase (CAT) and glutathione peroxidase (GPx) activities; however, the activities were not changed in gill and muscle tissues for GPx and in gill, muscle, and kidney tissues for CAT. Protein levels decreased in kidney, muscle, and alimentary tract, while increased in gill and alimentary tract in 15 days. With respect to these results, diazinon has oxidative and neurotoxic potentials in O. niloticus. Observed changes with diazinon treatment were generally tissue-specific and dose-dependent.     

Sperm competition and the evolution of sperm form and function in mammals

Sperm competition is a powerful selective force that has influenced many reproductive traits in males and females although additional evolutionary explanations may help to understand the diversity of mammalian reproduction. Sperm morphology varies considerably in mammals with extreme examples in several rodent lineages in which a wide range of sizes and complex head morphologies have been identified. Mammalian spermatozoa also differ in function, with swimming velocity and trajectory showing much divergence. Underlying processes mediating function have received little attention so far, but differences in timing and proportion of sperm undergoing capacitation or acrosomal exocytosis may be related to variation in signalling processes. Furthermore, energy required for sperm functions (such as motion, signalling and overall maintenance of cell integrity) can be produced and consumed, following different patterns among species and this could be the result of several selective forces. A more thorough understanding of the diversity in structure and function of sperm cells, and underlying selective forces, may help us develop better methods to assess them taking into account particulars and generalities of sperm form and performance. Such tests could then become more reliable in estimations of the impact of cryopreservation or effect of changes in the environment and their relevance for fertility.