不同饵料养殖黄喉拟水龟效果的研究

用5种不同的饵料(中华鳖配合饲料、蚯蚓、鲢鱼肉、福寿螺肉和河蚌肉)分别投喂黄喉拟水龟幼龟,结果表明,①投喂中华鳖配合饲料的黄喉拟水龟,其增重速度最快,平均日增重和蛋白质效率都最高,且耗料增重比最低,其后依次是: 蚯蚓＞鲢鱼肉＞福寿螺肉＞河蚌肉.②投喂福寿螺肉的黄喉拟水龟,其饵料成本最低,其后依次是: 中华鳖配合饲料＞蚯蚓＞河蚌肉＞鲢鱼肉.③中华鳖配合饲料是养殖黄喉拟水龟较好的饵料,但福寿螺、蚯蚓来源方便,也不失为养殖黄喉拟水龟的好饵料.     

不同养殖方式下黄喉拟水龟的增重及其经济效益的对比研究

分别采用常温养殖法和“两头加温”养殖法对黄喉拟水龟进行为期两周年的养殖对比研究,结果表明,常温养殖法养殖的黄喉拟水龟平均个体重由16 g增加到306.6 g,平均日增重0.40 g,生长增重模式为：W常=14.3186（1.0042）D（r=0.9613,F=2026.38）,饵料系数为8.35,成活率75%,增重1 kg活体需成本59.45元;“两头加温”法养殖的黄喉拟水龟平均个体重由16 g增加到642.3 g,平均日增重0.86 g,生长增重模式为：W加=19.2088（1.0048）D（r=0.9661,F=142.35）,饵料系数为7.82,成活率为90%,增重1 kg活体需成本93.63元.试验期间,采用“两头加温”法养殖的黄喉拟水龟获利4481.80元,是常温养殖法78.56元的57倍.     

人工条件下不同饲料饲养金钱龟效果的研究

为提高作为家庭观赏动物金钱龟的养殖效果,进行了鲜活饲料、水龟配合饲料及二者混合饲料养殖效果的比较研究.经过320 d实验,利用粗蛋白含量35.2%的水龟配合饲料喂养,饲料成本最低,效率显著高于鲜活饲料组和混合饲料组(P<0.05),但体重增长率显著低于其他两组(P<0.05);从养殖成本、饲料转化率及日常管理考虑,配合饲料优于鲜活饲料.     

不同饵料对史氏鲟仔鱼消化酶活性的影响

用活饵料(水丝蚓)、商品饵料、添加消化酶制剂的商品饵料、活饵料与商品饵料交替使用(对照组)来投喂10～40日龄(DPH,Day＿past＿hatch)的史氏鲟仔鱼。其中对照组仔鱼体内蛋白酶活性和商品饵料组及添加消化酶组的差异极显著(P<0.01),与活饵料组差异不显著(P>0.05),活饵料组仔鱼蛋白酶活性与商品饵料组差异极显著(P<0.01),与添加消化酶组差异显著(P<0.05),商品饵料组和添加消化酶组之间仔鱼的蛋白酶活性差异不显著(P>0.05);各饵料组仔鱼的淀粉酶活性差异均不显著(P>0.05);活饵料组和对照组仔鱼的脂肪酶活力与商品饵料及添加消化酶组仔鱼的脂肪酶活性差异极显著(P<0.01),在这两组之间,仔鱼的脂肪酶活性差异均不显著(P>0.05)。     

UV-B辐射对黄芩幼苗生长及生理生化指标的影响

对经过11.8 μW·cm-2 UV-B连续辐照7 d后黄芩(Scutellaria baicalensis Georgi)幼苗的生长及一些生理生化指标进行了测定和分析.结果表明:经11.8 μW·cm-2 UV-B辐照7 d后,黄芩幼苗的平均株高和单株平均干质量分别为8.1 cm和0.026 g,与对照无显著差异(P>0.05);叶片的叶绿素a、叶绿素b、总叶绿素及类胡萝卜素含量分别为2.89、1.04、3.93和0.48 mg·g-1,均极显著低于对照(P<0.01);叶绿素a/b比值以及类胡萝卜素/总叶绿素比值分别为2.78和0.122, 分别显著或极显著高于对照(P<0.05,P<0.01);叶片中的CAT和POD活性均极显著高于对照(P<0.01),分别为2 412和2 208 U·g-1;SOD活性(1 228 U·g-1·h-1)较对照略有升高,但差异不显著(P>0.05);叶片中的抗坏血酸(ASA)及游离脯氨酸含量均显著高于对照(P<0.05),分别为11.5 mg·g-1和57.7 μg·g-1;MDA含量高于对照,紫外吸收物相对含量和苯丙氨酸解氨酶(PAL)活性均低于对照,但差异不显著(P>0.05).研究结果显示,11.8 μW·cm-2 UV-B连续辐照7 d对黄芩幼苗的生长无显著抑制作用,黄芩幼苗能够通过自身的抗氧化系统有效减轻UV-B辐射产生的氧化损伤,对UV-B辐射表现出一定的耐受能力.     

黄喉拟水龟细胞核DNA含量的分析

以黄喉拟水龟 (Mauremysmutica)的红血细胞为材料 ,以鸡红血细胞为DNA标准 ( 2 5pg/2c) ,采用流式细胞仪测定了黄喉拟水龟及其两个种群的细胞核基因组DNA含量。黄喉拟水龟的细胞基因组DNA含量为 5 16± 0 2 9pg/2c (n =6 0 ) ;南方种群的细胞核DNA含量为 5 19± 0 30pg/2c (n =30 ) ,北方种群为 5 14±0 30pg/2c (n =30 ) ,两个种群的核DNA含量无显著差异 (t=0 6 84 7,df =5 8,P >0 0 5 )。     

黄喉拟水龟（♀）与三线闭壳龟（♂）杂交后代的形态特征及其与父母本的比较研究

本研究通过黄喉拟水龟Mauremys mutica（♀）与三线闭壳龟Cuora trifasciata（♂）进行杂交,成功获得了杂种龟。这说明黄喉拟水龟和三线闭壳龟是可以进行属间远缘杂交的,但杂交组合的受精率及孵化成功率均低于黄喉拟水龟的同种组合。杂种稚龟与黄喉拟水龟稚龟在背甲纹路、腹甲黑斑、四肢和尾腹面的皮肤颜色、喉盾前端形状及起点位置、喉盾宽/喉盾缝长、喉盾缝长/肱盾缝长、股盾缝长/肛盾缝长存在差异。1龄前,杂种龟生长快于黄喉拟水龟。形态特征上,杂种龟头顶部淡棕黄色,头侧眼后有两条黑色纵纹,颈腹部淡黄色;背甲棕色,腹甲浅黄色,每一盾片中间都有边缘呈放射状的黑斑;四肢、尾腹面及裸露皮肤部分为黄褐色。形态可量数据分析显示杂种龟在形态上接近黄喉拟水龟。建立了三种龟的形态判别公式,判别的准确率为100%（p<0.01）,判别分析中贡献最大的4个变量分别是腹甲后半部长/背甲长、喉盾宽/背甲长、肱盾缝长/背甲长、股盾缝长/背甲长,可见三线闭壳龟、黄喉拟水龟与杂交种腹部的腹甲后半部长、喉盾宽、肱盾缝长、股盾缝长等参数可作为鉴别三者的直接依据。本实验的结果对杂种龟的鉴定、龟类的杂交育种及养殖生产实践都有一定的借鉴作用。     

初乳中主要组分的动态变化及产妇年龄和剖宫产的影响

测定了来自20位健康母亲(其中8位为剖宫产)的118份初乳(泌乳第1～7d)中乳糖和蛋白质浓度.通过线性模型,分析产妇年龄和剖宫产对乳糖和蛋白质含量的影响.结果表明,乳糖在泌乳第1d最低,在泌乳1w内增加,其中泌乳第1d的乳糖浓度极显著低于第7d(P＜0.01).乳蛋白的浓度在泌乳第1d最高,泌乳1w内下降,其中前3d水平显著或极显著高于第7d(P＜0.05或P＜0.01).初乳中乳糖和乳蛋白含量呈极显著负相关(r=-0.523,P＜0.01).剖宫产母亲初乳中乳糖含量显著低于顺产(P＜0.05),剖宫产与顺产母亲初乳中蛋白质含量差异不显著(P＞0.05).产妇年龄的大小与初乳中蛋白质和乳糖含量均无显著关系(P＞0.05).     

溶藻细菌L7对水华鱼腥藻氮代谢的影响

【目的】进一步探明藻菌关系,研究溶藻细菌对藻类氮代谢的影响及其作用机制。【方法】将水华鱼腥藻和溶藻细菌L7按两种比例接种入BG11培养液中,在室内进行共培养(藻细胞初始密度为1.21×108cells/L;溶藻细菌L7初始密度分别为1.75×107、1.75×108CFU/mL)。连续7 d测定藻细胞数、异形胞频率和藻细胞内的硝酸还原酶(NR)活性、谷氨酰胺合成酶(GS)活性、谷氨酸合成酶(GOGAT)活性、蛋白质含量、丙二醛(MDA)含量。【结果】低密度溶藻细菌L7能够促进藻生长(第7天藻细胞密度是对照组的1.58倍),增加异形胞频率(第7天高于对照组66.67%);高密度则会抑制藻生长(第7天藻细胞密度相比对照组下降98.84%),降低异形胞频率(第7天为0)。在藻细胞内氮代谢关键酶活性方面,接种后2 5 d,两处理组中藻细胞内NR和GOGAT活性均极显著高于对照组(P<0.01);接种后0 5 d,高密度处理组的GS活性极显著高于对照组(P<0.01),而低密度处理组的则在大部分时间内极显著低于对照组(P<0.01)。在整个实验期内,低密度处理组中藻细胞内蛋白质含量一直极显著高于对照组(P<0.01);而在高密度处理组中,除第5天外,细胞内蛋白质含量则全部极显著低于对照组(P<0.01)。接种后2 4 d,高密度处理组中藻细胞内MDA含量呈现上升趋势,并极显著高于其余两组(P<0.01)。【结论】低密度溶藻细菌L7能够提高水华鱼腥藻对氮源的需求,加速蛋白质合成,促进氮代谢;而高密度溶藻细菌L7会对藻细胞产生过氧化伤害,阻碍蛋白质合成和氮代谢过程。     

黄喉拟水龟转铁蛋白重组表达及抗菌活性分析

转铁蛋白具有多种生物学功能,不仅参与铁的转运,而且具有抗菌、免疫调节等功能。对黄喉拟水龟转铁蛋白(Mauremys mutica transferrin,MaTf)原核表达、重组蛋白纯化、抗菌活性检测及MaTf在蛋白水平的表达特征进行了分析研究。通过用RT-PCR技术扩增MaTf的编码序列,克隆至载体pET-32 a(+);转化BL21(DE3),构建了其原核表达载体;优化表达条件(30℃,4h,0.8 mmol/L IPTG),使MaTf融合蛋白在BL21中高效表达;采用His Bind柱亲和层析与浓缩的方法纯化目的蛋白,Western blot证实获得纯度较高的MaTf重组蛋白;抑菌试验表明,MaTf重组蛋白对金黄色葡萄球菌、大肠杆菌和黏质沙雷氏菌均有明显的抑菌作用;用MaTf重组蛋白制备多克隆抗血清,Western blot免疫印记法分析转铁蛋白在体内的表达特征,结果显示其在肝脏、脾脏、肾脏、心脏4个组织中的表达量为:肝脏>脾脏>肾脏>心脏,与MaTf在RNA水平上的表达特征具有相似性。研究为探索转铁蛋白在黄喉拟水龟非特异性免疫反应中的作用提供了重要信息。     

Mitochondrial DNA reveals multiple Northern Hemisphere introductions of Caprella mutica (Crustacea, Amphipoda)

Caprella mutica (Crustacea, Amphipoda) has been widely introduced to non-native regions in the last 40 years. Its native habitat is sub-boreal northeast Asia, but in the Northern Hemisphere, it is now found on both coasts of North America, and North Atlantic coastlines of Europe. Direct sequencing of mitochondrial DNA (cytochrome c oxidase subunit I gene) was used to compare genetic variation in native and non-native populations of C. mutica . These data were used to investigate the invasion history of C. mutica and to test potential source populations in Japan. High diversity (31 haplotypes from 49 individuals), but no phylogeographical structure, was identified in four populations in the putative native range. In contrast, non-native populations showed reduced genetic diversity (7 haplotypes from 249 individuals) and informative phylogeographical structure. Grouping of C. mutica populations into native, east Pacific, and Atlantic groups explained the most among-region variation (59%). This indicates independent introduction pathways for C. mutica to the Pacific and Atlantic coasts of North America. Two dominant haplotypes were identified in eastern and western Atlantic coastal populations, indicating several dispersal routes within the Atlantic. The analysis indicated that several introductions from multiple sources were likely to be responsible for the observed global distribution of C. mutica , but the pathways were least well defined among the Atlantic populations. The four sampled populations of C. mutica in Japan could not be identified as the direct source of the non-native populations examined in this study. The high diversity within the Japan populations indicates that the native range needs to be assessed at a far greater scale, both within and among populations, to accurately assess the source of the global spread of C. mutica .     

A genetic survey of heavily exploited, endangered turtles: caveats on the conservation value of trade animals

Asian turtles face an extinction crisis, and so it is imperative that systematists accurately determine species diversity in order to guide conservation strategies effectively. We surveyed mitochondrial and nuclear DNA (mtDNA and nuDNA) variation of the heavily exploited Mauremys mutica complex, a clade of Asian turtles that contains the endangered M. mutica from Japan, Taiwan, China and Vietnam, and the critically endangered Mauremys annamensis from central Vietnam. We discovered extensive mtDNA and nuDNA variation among samples that did not correspond to the currently recognized taxonomy. Both nuDNA and mtDNA data suggest that M. mutica is paraphyletic with respect to M. annamensis . Surprisingly, M. annamensis exhibits a previously unknown mtDNA structure in the form of two clades that are paraphyletic to M. mutica . These data reveal that the currently recognized taxonomy of the mutica complex does not reflect the genetic diversity of our samples. Unfortunately, many conservation-oriented captive-breeding efforts for turtles are also based on trade samples such as the ones studied here. These efforts include plans to breed trade-rescued individuals and release their progeny into the wild. Because our genetic survey reveals that the taxonomic identity of these samples does not reflect genetic diversity, we raise serious questions about the efficacy of these programs. In order to address conservation issues and provide more accurate estimates of evolutionary lineages within Mauremys , we recommend continued surveys for wild populations of the mutica complex to provide new genetic material and additional distributional data, attempts to extract DNA from historic museum specimens and a shift in conservation focus to in situ preservation of wild populations and associated habitat.     

Characterization of gingival epithelium epidermal growth factor receptor

The binding characteristics of gingival epithelium epidermal growth factor (EGF) receptor were investigated using epithelial cell membranes from bovine gingiva. The binding of [125I]EGF was found to be time and protein concentration dependent, reversible, and specific. Unlabeled EGF competed for [125I]EGF binding with IC50 of 0.25nM and maximum displacement of 93% at 0.81nM. Scatchard analysis of the binding data inferred the presence of two binding sites, one of high affinity (Kd = 3.3 nM and Bmax = 47.3fmol/mg protein) and the other of a low affinity (Kd = 1.6 microM and Bmax = 1.9pmol/mg protein). Crosslinking of [125I]EGF to gingival membranes followed by polyacrylamide gel electrophoresis and autoradiography revealed a receptor protein of 170kDa.     

低浓度Cry1Ac毒蛋白对棉大卷叶螟连续三代生长发育与繁殖的影响

棉大卷叶螟是棉花生长中后期的重要食叶性害虫.本研究以浸叶法测定低浓度(0.5 μg·g^-1)的Cry1Ac毒蛋白处理对棉大卷叶螟连续3个世代生长发育与种群增长的影响.结果表明: 处理后的棉大卷叶螟幼虫期比对照延长1.78～2.00 d,成虫寿命延长1.44～1.94 d,蛹体质量增加5.3%～11.8%;3个世代的单雌产卵量分别增加65.1%、47.3%和37.6%,种群趋势指数分别提高11.4%、17.5%和20.0%.这些指标与对照均存在显著差异.蛹历期、羽化率、性比和卵孵化率等与对照无显著差异.研究表明,转Bt基因棉长期种植后棉大卷叶螟的种群数量将会增加,需要进一步评估转基因棉种植的风险性,加强转基因棉田害虫的综合治理.     

Isolation and characterization of metallothionein from the tortoise Clemmys mutica

A relatively high concentration of metallothionein was present in the liver of the control mature tortoise Clemmys mutica. The administrations of cadmium and copper to Clemmys mutica increased the metals in the liver with concomitant decrease of zinc, which was due to substitution of zinc in the native metallothionein with cadmium and copper. The Clemmys metallothionein was a mixture of three isoproteins which were abundant in half-cystine (34.2-34.6 mol%) and lysine (10.8-11.9 mol%), but lacked aromatic amino acids. One of the isoproteins, MT-I, contained one residue of histidine, which was an identical feature with frog and avian metallothioneins.     

Evolution of the gene network underlying gonadogenesis in turtles with temperature-dependent and genotypic sex determination

The evolution of sex determination has long fascinated biologists, as it has paramount consequences for the evolution of a multitude of traits, from sex allocation to speciation and extinction. Explaining the diversity of sex-determining systems found in vertebrates (genotypic or GSD and temperature-dependent or TSD) requires a comprehensive and integrative examination from both a functional and an evolutionary perspective. Particularly revealing is the examination of the gene network that regulates gonadogenesis. Here, I review some advances in this field and propose some additional hypotheses about the composition of the gene network underlying sexual development, the functional links among some of its elements and their evolution in turtles. I focus on several pending questions about: (1) What renders TSD systems thermo-sensitive? (2) Is there one developmentally conserved or multiple TSD mechanisms? (3) Have evolutionarily derived GSD species lost all ancestral thermal-sensitivity? New data are presented on embryonic expression of Dax1 (the dosage-sensitive sex-reversal adrenal hypoplasia congenital on the X chromosome gene in the turtles Chrysemys picta (TSD) and Apalone mutica (GSD). No differential Dax1 expression was detected in C. picta at any of the stages examined, consistent with reports on two other TSD turtles and alligators. Notably, significantly higher Dax1 expression was found at 30°C than at 25°C at stage 15 in A. mutica (GSD), likely caused by Wt1's identical expression pattern previously reported. Because Sf1 is an immediate downstream target of Dax1 and its expression is not affected by temperature, it is proposed that Sf1 renders Dax1's differential signal ineffective to induce biased sex ratios in A. mutica, as previously proposed for Wt1's thermosensitive expression. Thus, it is hypothesized that Sf1 plays a major role in the lack of response of sex ratio to temperature of A. mutica, and may function as a sex-determining gene in this GSD species. These and previous data permit formulating several mechanistic hypotheses: (1) the postulation of Wt1 as a candidate thermal master switch alone, or in combination with Sf1, in the TSD turtle C. picta; (2) the proposition of Sf1 as a sex-determining gene in the GSD turtle A. mutica; and (3) the hypothesis that differing patterns of gene expression among TSD taxa reflect multiple traits from a developmental perspective. Moreover, the recent finding of relic differential Wt1 expression in A. mutica and the results for Dax1 in this species provide empirical evidence that GSD taxa can harbor thermal sensitivity at the level of gene expression, potentially co-optable during TSD evolution.     

Comparative molecular phylogeography of North American softshell turtles (Apalone): implications for regional and wide-scale historical evolutionary forces

We use a comparative analysis of partial cytochrome b sequences to evaluate the evolutionary forces shaping wide-scale phylogeographic patterns of all three North American softshell turtles (Apalone ferox, A. mutica, and A. spinifera). The overall phylogeographic patterns are concordant with results from both extensive regional studies of southeastern species, implicating historical vicariant processes during the Pliocene and Pleistocene, and investigations of more northerly distributed species, indicating a bottleneck effect of recent dispersal into postglacial habitat. We also resolved a novel, shared genetic break between northern-western and southeastern populations within both A. mutica and A. spinifera, demonstrating the value of using widespread taxa to evaluate both regional and wider scale phylogeographic patterns. The extensive phylogenetic structure and sequence divergences within both A. mutica and A. spinifera contrast sharply with most previous studies of turtles and with the hypothesis that turtles in general have slow rates of mtDNA evolution.