饥饿对食蚊鱼和唐鱼幼鱼能量物质消耗及游泳能力的影响

为探究食蚊鱼和唐鱼在遭受饥饿胁迫时其能量物质消耗利用特征以及在游泳能力上的响应在室内(25±1)℃水温下设0(对照组)、10、20、30和40 d5种饥饿时间,研究了饥饿对食蚊鱼和唐鱼幼鱼主要能量物质消耗以及对爆发游泳速度(U_(burst))和临界游泳速度(U_(crit))的影响,旨在从能量代谢和游泳行为角度探讨食蚊鱼和唐鱼幼鱼应对饥饿胁迫的策略及其种间差异.结果表明:饥饿前(0 d对照组),食蚊鱼糖原和脂肪含量均显著小于唐鱼,蛋白质含量却与唐鱼无显著差异,而无论何种游泳速度,食蚊鱼均显著小于唐鱼.经历不同饥饿时间后,两种鱼糖原含量均随饥饿时间增加呈显著幂函数曲线下降趋势,并在饥饿10d时接近于0,而脂肪和蛋白质含量均随饥饿时间呈显著线性下降.与唐鱼相比,食蚊鱼脂肪-饥饿时间线性方程斜率显著降低,但蛋白质-饥饿时间方程斜率却显著增加.饥饿40 d后,食蚊鱼和唐鱼能量物质消耗率均显示为糖原脂肪蛋白质;但从能量物质的绝对消耗量来看,食蚊鱼表现为蛋白质脂肪糖原,而唐鱼则是脂肪蛋白质糖原.而无论何种试验鱼,其U_(burst)和U_(crit)均随饥饿时间增加呈显著线性下降,且U_(burst)-饥饿时间线性方程斜率均显著小于U_(crit)-饥饿时间方程.与唐鱼相比,食蚊鱼U_(burst)-饥饿时间线性方程斜率无显著变化,但U_(crit)-饥饿时间线性方程斜率却显著降低.结果表明,饥饿胁迫下2种鱼的能量物质消耗利用特征与游泳能力变化密切相关.相比唐鱼,食蚊鱼虽然整体上能量储备较少,游泳能力较低,但在饥饿期间却主要利用储存量更大的蛋白质供能,饥饿后脂肪含量下降幅度小于唐鱼,其U_(crit)变化比唐鱼更加稳定,这从一定程度上表明其具有更强的耐饥饿潜力,为适应营养匮乏的溪流生境提供了有利条件.     

饥饿对太平洋鲑生长、机体组成及血浆相关生化指标变化研究

实验研究了太平洋鲑鱼(Oncorhynchus spp.)经8-32d饥饿后对其生长、体组成与血浆生化指标变化的影响。90尾初始重约为217g的太平洋鲑鱼放养于0.25m3的水族箱中0-32d,水温为(17.0±2.9)℃。实验分5组,分别为对照组(饥饿0d)、实验1组(饥饿8d)、实验2组(饥饿16d)、实验3组(饥饿24d)、实验4组(饥饿32d)。每组3个平行,每箱6尾鱼。结果表明:饥饿期间,太平洋鲑鱼存活率均为100%,相对体重损失率与饥饿时间直线回归方程为y=0.0086x(R2=0.9177),呈显著的正相关(P0.05);肠系膜脂肪是太平洋鲑鱼最主要的能量来源,与饥饿时间呈显著的负相关(P0.05),其直线回归方程y=-0.0719x±4.11(R2=0.9732);饥饿初期太平洋鲑鱼主要消耗肝脏糖原和脂肪、部分肠系膜脂肪和少许肌肉中脂肪维持生命活动,能耗较低;饥饿后期主要以消耗肠系膜脂肪、部分肌肉脂肪和少量蛋白质维持生命活动,能耗较高;血浆中脂肪分解酶和白蛋白无显著变化(P0.05),胆固醇、甘油三酯和高低密度脂蛋白有显著波动(P0.05),表明脂肪代谢活跃,免疫功能未受明显影响。研究表明太平洋鲑鱼能够有效地利用体内储存的脂肪,对饥饿的耐受能力较强。       

三疣梭子蟹UHRF1基因在胚胎、幼体和性腺发育过程中的表达分析

为探讨泛素样含PHD和环指域蛋白1(UHRF1)基因在三疣梭子蟹(Portunus trituberculatus)发育过程中的作用, 实验采用SMART RACE方法, 克隆了三疣梭子蟹UHRF1(PtUHRF1)基因。该基因cDNA全长为2849 bp, 开放阅读框(ORF)为2298 bp, 预测其编码1个含有765个氨基酸的蛋白质。结构域分析显示, 该蛋白质包含UBL、PHD、TTD、SRA、RING finger 5个功能结构域。同源分析表明, 三疣梭子蟹PtUHRF1的氨基酸序列与其他物种有较高的同源性。qRT-PCR结果显示, PtUHRF1基因在三疣梭子蟹所有组织中均有表达, 但在精巢中表达量显著高于其他组织。该基因在胚胎和幼体发育不同时期表达差异显著, 在受精卵中的表达量最高, 并显著高于胚胎发育其他时期, 是多细胞时期表达量的2.5倍。PtUHRF1基因在性腺发育不同时期表达存在显著差异, 在卵巢II期表达量达到峰值, 之后逐渐下降; 在精巢Ⅰ期的表达量最高, 随着精巢发育逐渐下降。实验结果表明, PtUHRF1参与了三疣梭子蟹胚胎、幼体和性腺发育调控, 为进一步深入研究该基因在三疣梭子蟹及甲壳动物生长发育中的作用提供参考。     

饥饿胁迫对中华绒螯蟹(Eriocheir sinensis)仔蟹的影响

在26.2 ～28.4℃水温条件下,研究了饥饿对中华绒螯蟹(Eriocheir sinensis)仔蟹的形态、行为、存活及体重损失的影响,同时确定了仔Ⅱ的营养饱和储存点(PRS)和不可恢复点(PNR).结果表明:饥饿胁迫下中华绒螯蟹仔Ⅰ、仔Ⅱ、仔Ⅲ的初次死亡时间(T1)分别为8.0、14.0和20.3 d,50％死亡时间(Ts0)分别为11.4、16.0和25.5 d,100％死亡时间(T100)分别为15.0、22.0和32.3 d,耐饥饿能力为仔Ⅲ＞仔Ⅱ＞仔Ⅰ;饥饿期间中华绒螯蟹体内水分含量持续升高,干重量降低显著,干重损失速率也随时间延长逐渐减小;先饱食后饥饿的给饵模式中仔Ⅱ蜕皮率随初始饱食时间延长而升高,50％个体完成蜕皮所需饱食时间(PRS50)为2.10d,各处理组仔Ⅱ的蜕皮周期与持续饱食组均无显著差异(P＞0.05),但只有饱食3d以上才能达到持续饱食饲养蟹的增重率;先饥饿后饱食的给饵模式中,仔Ⅱ的蜕皮率随着初始饥饿时间的延长而下降,其中仔Ⅱ50％不能蜕皮的初始饥饿时间(PNR50)和100％不能蜕皮的初始饥饿时间(PNR100)分别为10 d和14 d,并且蜕皮周期相对延长,延长时间约等于初始饥饿时间,不存在额外的摄食时间来弥补饥饿期间损失的能量,各处理组蜕皮后仔蟹与对照组体重无显著差异(P＞0.05).     

饥饿胁迫对曼氏无针乌贼幼体的影响

以曼氏无针乌贼(Sepiella maindroni)初孵幼体为材料,分析了饥饿胁迫对幼体存活、行为变化,消化酶活力,脂肪酸组成,以及饥饿后再投喂对幼体生长及成活率的影响.结果表明:饥饿对曼氏无针乌贼幼体存活、体态和游动行为的影响较大,至第7天全部死亡.初孵幼体的胃蛋白酶活力在饥饿5d时出现最低值0.23±0.04 U·mg-1·prot-l;胰蛋白酶活力在饥饿5d时最高为737.30±26.26 U·mg-1·prot-1;淀粉酶活力在饥饿5d时降至最低13.93±2.00 U·g-1·prot-1;脂肪酶活力在饥饿2d时最低17.46±0.79 U·g-1·prot-1.饥饿状态下,机体消耗利用自身脂肪酸成分的顺序依次为:饱和脂肪酸,单不饱和脂肪酸,多不饱和脂肪酸中的低不饱和脂肪酸,最后是高不饱和脂肪酸.曼氏无针乌贼的不可逆点(PNR)为第5天.实验结果有助于合理制定曼氏无针乌贼育苗前期饵料的投喂策略.     

饥饿对黑鲷血清生长激素、甲状腺激素以及白肌和肝脏脂肪、蛋白质含量的影响

饥饿处理黑鲷 (Sparusmacrocephalus) 2、 5、 10、 15和 30d ,分别测定血清生长激素 (GH)和甲状腺激素三碘甲状腺原氨酸 (T3 )浓度以及脂肪和蛋白质在白肌和肝脏中的含量 ;同时测量正常摄食动物的相应指标作为对照。数据分析结果显示 :①饥饿 15d后血清GH水平显著升高 ,T3 水平显著降低 ;②饥饿 15d后白肌蛋白质含量显著降低 ,而脂肪含量则在饥饿 2d就降低 ,并维持此低水平 ;③肝脏脂肪含量在饥饿 10d后显著升高 ,而蛋白质呈不规则波动。GH水平升高能强化储能物质的转化 ,而T3 水平降低可降低代谢水平。二者的协同作用很可能是该种应对饥饿胁迫的重要生理反应机制     

三疣梭子蟹胚胎发育过程中肝胰腺的发生与卵黄物质利用的关系

通过对三疣梭子蟹胚胎进行连续采样和组织切片,系统研究了三疣梭子蟹胚胎发育过程中卵黄囊和肝胰腺的发生与卵黄物质利用的关系。结果表明:(1)三疣梭子蟹胚胎的卵黄岛和卵黄囊结构分别出现在原肠期和无节幼体期,胚胎从原肠期至卵内第一期溞状幼体期,始终存在卵黄岛结构,且卵黄岛中的卵黄物质不断被分解和利用. (2)卵内第二期溞状幼体后,卵黄囊分为两个区域,卵黄囊壁中出现肝胰腺细胞(柱状上皮细胞),此时肝胰腺前体已开始形成,卵黄岛开始融合. (3)卵内第三期溞状幼体阶段,卵黄囊发育成一双肝胰腺,由于肝胰腺中的卵黄物质互相融合,卵黄岛结构消失。此阶段胚胎对卵黄物质的利用加快, 卵黄物质中存在许多空泡状结构;(4)胚胎发育进入孵化前期后,肝胰腺腔内的卵黄物质极少,而初孵溞状幼体肝胰腺腔内卵黄物质已完全消失,肝胰腺为一对囊状结构。这些结果表明在三疣梭子蟹胚胎发育从原肠期到孵化前的过程中,卵黄岛和肝胰腺细胞对于卵黄物质分解和利用起着十分重要的作用。     

稀有鮈鲫仔鱼的摄食和耐饥饿能力

研究了室养条件下稀有的鮈鲫的摄食和耐饥饿能力。结果表明,仔鱼一般在孵出后1.5d-2d开口摄食,此时卵黄囊容量约从初孵时的0.1降至0.03mm~3以下,在其后1-1.5d卵黄物质消耗殆尽;饥饿仔鱼的初次摄食率变化型式为:开始较低,然后迅速升高,约在卵黄吸尽时达到最高,最高初次摄食率为100％,保持在80％以上的时间为5d;持续饥饿或延迟开始摄食时间对仔鱼的生长、发育、存活有深刻的影响,饥饿仔鱼全长负生长及饥饿体征明显;初孵仔鱼持续饥饿8-10d达不可逆点(PNR),饥饿仔鱼在PNR前1.5d时存活率低于50％,在PNR后2d全部死亡。     

淡水养殖太平洋鲑循环饥饿后补偿性生长效果研究

用16.1%脂肪,38.1%蛋白质含量日粮饲养108尾初始重约为240g的太平洋鲑(Oncorhynchusspp.)于0.25m3的水族箱中64d,水温为15.5±3.7℃。实验分6组,分别为对照组(每天投喂),实验1组(隔天投喂),实验2组(隔2天投喂2天),实验3组(隔4天投喂4天),实验4组(隔8天投喂8天),实验5组(隔16天投喂16天)。每组设3个平行水族箱,每箱6尾鱼。研究淡水养殖太平洋鲑多重周期饥饿后补偿性生长效果。实验结果表明:(1)各试验组太平洋鲑成活率均为100%。实验1、2、3组太平洋鲑鱼体增重接近对照组,其恢复摄食期间特定生长率、摄食率、食物转化率均显著或极显著高于对照组(P<0.05或0.01)。而实验4、5组鱼恢复摄食期间虽摄食率极显著高于对照组(P<0.01),但其鱼体增重、特定生长率、食物转化率均极显著低于对照组(P<0.01);(2)实验各组鱼肥满度、肝体比、肝脏脂肪和糖原含量、肌肉中脂肪含量较对照组均有不同程度下降,肝脏脂肪中总饱和脂肪酸比例上升,而总多不饱和脂肪酸比例下降;(3)实验1、2、3组血浆中甘油三酯、胆固醇和低密度脂蛋白显著低于对照组,而葡萄糖、血清中甲状腺激素T4浓度显著高于对照组(P<0.05)。实验结果表明,初重约240g太平洋鲑饥饿1—4d,再循环投喂相同时间64d后,获得了接近完全补偿生长效果,表现为其恢复摄食期间摄食率和食物转化率明显上升,生长速率明显加快,饲料报酬明显提高,鱼体增重接近持续喂食的对照组,养殖效益明显提高。但饥饿8—16d再循环投喂相同时间后,表现为无补偿生长效应,食物转化率和生长速率明显下降,鱼体增重极显著低于持续喂鱼的对照组。     

饥饿和再投喂对虎斑乌贼幼体存活、生长和消化酶活力的影响

本文探究了饥饿胁迫与饥饿后再投喂对虎斑乌贼幼体存活率、生长、行为、肝体比、摄食率以及消化酶活力的影响.在室内控制条件下开展了幼体(初始体质量为4.95±0.48 g)的饥饿(0、1、2、3、4、5、6 d)和再投喂(15 d)试验.结果表明: 不同饥饿时间对虎斑乌贼的幼体存活率、体质量降低率、肝体比和消化酶活力影响显著.随着饥饿胁迫时间的增加,其存活率、肝体比呈下降趋势,其中饥饿3 d后,存活率开始明显下降,体质量降低率明显增大,幼体出现喷墨、互相残杀等异常行为;4种消化酶活力呈先下降后上升的趋势,淀粉酶活力以饥饿4 d组最低 (0.07±0.02 U·mg^-1·prot^-1);脂肪酶活力以饥饿2 d组最低(18.47±2.07 U·g^-1·prot^-1),饥饿6 d组最高(57.60±3.98 U·g^-1·prot^-1),胃蛋白酶活力和胰蛋白酶活力以饥饿5 d组(1.98±0.59 U·mg^-1·prot^-1)和饥饿4 d(186.68±20.72 U·mg^-1·prot^-1) 最低.饥饿处理结束后,经15 d再投喂,各试验组存活率、特定生长率、肝体比和摄食率差异显著,幼体的存活率、特定生长率、肝体比和摄食率均与饥饿处理时间呈负相关;饥饿1和2 d组与对照组的存活率、特定生长率和肝肝体比无显著差异,而饥饿3～6 d组显著低于对照组;饥饿1～2 d组的摄食率明显高于对照组,而饥饿6 d组的摄食率明显小于对照组;各组淀粉酶与脂肪酶活力无显著差异,胃蛋白酶与胰蛋白酶活力差异显著,均以对照组最高(胃蛋白酶活力7.06±0.64 U·mg^-1·prot^-1,胰蛋白酶活力914.67±26.54 U·mg^-1·prot^-1),饥饿6 d组最低(胃蛋白酶活力3.21±0.57 U·mg^-1·prot^-1,胰蛋白酶活力660.04±37.92 U·mg^-1·prot^-1).说明虎斑乌贼的幼体饥饿不可逆点(PNR)为第6天,且不能补偿生长.     

(AGCTG) (AGCTG) (AGCTG) (GGGTG) as the primordial sequence of intergenic spacers: the role in immunoglobulin class switch

The means employed for immunoglobulin heavy chain class switch appears to be no different from that by which meiotic intergenic crossing-overs at accomplished. As with other intergenic spacers, the 5' noncoding sequence of each Ig CH (immunoglobulin heavy chain constant region) gene apparently undergoes unconstrained sequence changes due to randomly sustained base substitutions, deletions, and duplications. Yet, there remains sufficient regional sequence homology between the Ig Cmu 5' noncoding sequence and those of its somatic recombination partners, e.g., Ig C gamma 1, Ig C gamma 2b, Ig C alpha, because each of these 5' noncoding sequences is made of multiple copies in various stages of degeneracy of one primordial 20 base pair-long sequence: (AGCTG) (AGCTG) (AGCTG) (GGGTG).     

Dioecism of the genusCallicarpa (Verbenaceae) in the Bonin (Ogasawara) Islands

The morphology and function of the flowers of three species of the genusCallicarpa, C. glabra, C. nisnimurae andC. subpubescens, endemic to the Bonin Islands, revealed that all three species were dioecious. Male plants had short-styled flowers with sterile ovaries, while female plants had long-styled flowers with non-germinating inaperturate pollen grains. Such dioecism has never been reported from the family Verbenaceae. This curious sexual system with non-germinating pollen grains may have been maintained as a reward to insect pollinators.     

Branchiopods (non-cladocerans) of the Maltese Islands (central Mediterranean)

Four branchiopod species occur on the Maltese Islands, viz. Branchipus schaefferi, B. visnyai, Cyzicus tetracerus and Triops cancriformis. All four live in freshwater pools, but it is noteworthy that, beside B. schaefferi, T. cancriformis was recorded from a mesohaline, coast-fringing habitat.     

天然型与非天然型脱落酸的生物活性比较

采用新方法精制脱落酸（ＡＢＡ）异构体试样,提高了（Ｓ）－（＋）－ＡＢＡ与（Ｒ）－（－）－ＡＢＡ两对映体纯度。抑制生长试验和残留量分析以及气孔闭合试验表明：天然型（Ｓ）－（＋）－ＡＢＡ活性显著高于非天然型（Ｒ）－（－）－ＡＢＡ或（ＳＲ）－（±）－ＡＢＡ。抑制莴苣种子发芽５０％的活性强度,（Ｓ）－（＋）－ＡＢＡ约是（Ｒ）－（－）－ＡＢＡ的５倍,（ＳＲ）－（±）－ＡＢＡ介于两者之间。抑制萝卜下胚轴生长试验,最显著有效期为２～６ｄ,生理作用期约为一周,（Ｓ）－（＋）－ＡＢＡ活性是（Ｒ）－（一）－ＡＢＡ的３．５倍。鸭跖革气孔闭合试验,（Ｓ）－（＋）－ＡＢＡ活性比（Ｒ）－（－）－ＡＢＡ高１倍。     

On the discussion of the wing venation of (Archae)Orthoptera (Insecta)

Alternative current approaches to homology and nomenclature of the insect wing venation are discussed. The differences between the opposing viewpoints are found to be not as deep as they have sometimes been supposed to be, and more so, there are some observations that could help to smooth current contradictions. However, this requires an understanding of the evidence presented by the disputants and, particularly, an understanding of their terminology.     

New(s) to the (Z-)ring

Cytokinesis in bacteria is mediated by a macromolecular machine known as the divisome, consisting of an assembly of FtsZ polymers around the cylindrical axis of the cell and the downstream regulators of division that are subsequently recruited to it. FtsZ polymerizes into filaments in a GTP-dependent manner, similarly to its eukaryotic structural homolog tubulin. The initial placement of the FtsZ polymerization site is tightly regulated by multiple mechanisms, as are the subsequent polymer reshaping and force generation that separate the two daughter cells from each other. New factors have been recently discovered that contribute to this regulation, notably affecting FtsZ polymer shaping, and modulating FtsZ polymerization in response to the metabolic or redox state of the cell.     

On the fauna of chironomidae (Diptera) of the Hrazdan Basin (Armenia)

A faunistic review of larvae and pupae of chironomid midges (Diptera, Chironomidae) from 15 habitats in the Hrazdan River valley (Armenia) is presented. The revealed fauna includes 40 species from 20 genera and 6 families and tribes. Diploid chromosome numbers are specified for 24 species from 13 genera and 4 subfamilies; 23 species from 14 genera and 4 subfamilies are reported from the region for the first time. Predominant oligotrophic status is confirmed for most of the reservoirs studied.     

Distribution of sulfhydryloxidase (SOx) immunoreactivity in the testis of the axolotl (Ambystoma mexicanum) (amphibia, urodela)

Immunohistochemical localization of sulfhydryloxidase (SOx) has been examined in the testis of the Axolotl (Ambystoma mexicanum). The urodelan testis contains germ cells in various phases of differentiation from primordial germ cells to mature spermatozoa. SOx immunoreactivity is present in mitochondria of primordial germ cells and primary spermatogonia and declines within the population of secondary spermatogonia, suggesting, that the antibody used to localize SOx may serve to estimate the developmental stage of spermatogonia towards meiosis, since more undifferentiated cells react positively. Intensity of immunostaining increases again in spermatocytes and becomes most intense in early round spermatids correlating on ultrastructural level with an accumulation of numerous mitochondria in that part of the cytoplasm, where the acrosome vesicle is formed. Mature sperm are immunonegative. Additionally, Leydig cells within the glandular tissue are stained by the antibody. Thus the distribution pattern of SOx immunoreactivity principally resembles that in the mammalian testis found during ontogenesis or in the adult seminiferous epithelium. The possible functional significance of mitochondrial SOx in germ cells and Leydig cells is discussed. These results suggest, that the amphibian testis is a model for experimental problems dealing with the investigation of germ cells in various developmental phases including very undifferentiated premeiotic germ cells. The cystic testis may be of value in studying influences of various experimental conditions on varied homogeneous populations of germ cells.     

Mechanism of the antistressor effect of D-Ala(2)-Leu(5)-Arg(6)-enkephalin

It has been shown that the stable analog of leu-enkephalin diminishes to a great extent the stress-induced changes in the blood content of ACTH, cortisol, hypophyseal-thyroid hormones, the CAMP level in the adrenal and thymic tissues of white rats. It is assumed that this circumstance may interfere with depletion of the adrenal cortex and suppression of the lymphoid-macrophagal system.