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.     

饥饿对三疣梭子蟹初孵幼体(Z1)存活及主要生化成分的影响

研究了饥饿对三疣梭子蟹(Portunus trituberculatus)初孵幼体(Z1)存活及主要生化组成的影响,同时分析饥饿期间的能量变化和能量来源。结果表明,1.三疣梭子蟹初孵幼体Z1的TI(初次死亡时间)、T50(50%死亡时间)和T100(100%死亡时间)的时间分别为2.5 d、6.0 d和9.5 d,饥饿第3 d,幼体活力显著下降;2.饥饿期间,幼体的蛋白质和脂肪含量显著下降,水分含量略有上升,脂肪/蛋白的值表现为高-低-高-低的变化趋势;3.饥饿期间,初孵幼体Z1体内的总能量显著下降,最初24 h的能量消耗最快,整个饥饿期间脂类、蛋白质供能比例分别为42.71%、57.05%。     

周期性饥饿再投喂对长蛸存活、生长以及肌肉脂肪酸和氨基酸的影响

在19.8—22.2℃条件下, 采用周期性饥饿再投喂的方法, 研究不同投喂模式对长蛸[Octopus minor, 初始体重(94.29±9.35) g, 初始胴背长(53.25±5.25) mm]的存活、生长以及脂肪酸和氨基酸的影响。实验分为4个组包括对照组(持续投喂)、S₁F₅组(周期性饥饿1d再投喂5d)、S₂F₄组(周期性饥饿2d再投喂4d)和S₃F₃组(周期性饥饿3d再投喂3d), 持续24d。实验结果如下: 随饥饿时间的延长, 增重率、肝体比、体重变化量以及终末体重四个指标均呈现出先上升后下降的趋势, 其中S₁F₅组的值均显著高于对照组, 而S₃F₃组的值除肝体比外均显著低于对照组。长蛸的成活率随饥饿时间的增长呈现出下降趋势, 但各实验组均与对照组差异不显著; 摄食量随饥饿时间的延长, 表现出上升趋势, 且三个实验组的值均显著高于对照组。在长蛸肌肉脂肪酸中, 饱和脂肪酸(SFA)、不饱和脂肪酸(UFA)、单不饱和脂肪酸(MUFA)以及多不饱和脂肪酸(PUFA)的含量均与对照组差异不显著, 但S₁F₅组的值与对照组相比出现了一定程度的升高; 在氨基酸含量上, 各实验组的必需氨基酸总量(TEAA)、氨基酸总量(TAA)以及必需氨基酸总量/氨基酸总量(TEAA/TAA)的值均与对照组差异不显著。综上所述, S₁F₅组和S₂F₄组长蛸出现了补偿生长现象, 且S₁F₅组长蛸具备超补偿生长能力。因此, 在长蛸的人工养殖过程中, 为保证其养殖效果, 建议采用周期性饥饿1d再投喂5d的投喂模式。     

温度和盐度对西藏拟溞抗氧化酶和脂质过氧化作用的影响

采用实验生态学方法,研究了温度(T=16、19、22、25、28℃)、盐度(S=5、10、15、20、25)对西藏拟溞总超氧化物歧化酶(TSOD)、谷胱甘肽过氧化物酶(GSH-PX)活力以及脂质过氧化产物丙二醛(MDA)含量的影响。结果表明:温度和盐度能够诱导西藏拟溞抗氧化应激反应,胁迫24h后,SOD、GPX活性及MDA含量在28℃、盐度20时均达到最高值,分别为(37.18±1.97)U mg-1μg-1、(75.1±9.96)U mg-1μg-1和(12.24±2.12)nmol mg-1μg-1;48h后,高温低盐组(25—28℃、5—10)和高温高盐组(25—28℃、20—25)SOD、GPX活性及MDA含量显著高于其他处理组(P0.05),在28℃,盐度5时均达到最大值,分别为(19.25±3.48)U mg-1μg-1、(59.95±4.66)U mg-1μg-1和(4.98±0.66)nmol mg-1μg-1;温度、盐度以及这两个因子之间对西藏拟溞体内SOD、GPX活性和MDA含量均有极显著影响(P0.01)。     

盐度对不同日龄日本无针乌贼幼体生长及存活的影响

对不同日龄(1日龄、7日龄、15日龄)的日本无针乌贼在不同盐度(10、15、20、25、30、35、40)条件下的生长及存活状况进行了研究。结果表明,各日龄组日本无针乌贼的存活率及增重率均随盐度的升高而升高,但当盐度超过一定值后,其存活率及增重率随盐度的升高而降低。日本无针乌贼的适宜盐度范围为20～30,不同日龄乌贼幼体的适宜盐度范围略有不同,其中15日龄幼体对盐度的耐受性要优于1日龄及7日龄乌贼幼体。乌贼幼体的最适盐度约为25,其生长和存活均较高。     

饥饿对食蚊鱼仔鱼摄食、生长和形态的影响

本文研究了饥饿胁迫下食蚊鱼仔鱼的摄食、生长和外部形态的变化规律.结果表明,在水温(28.5±1.2)℃时,仔鱼产出2h后鳔完成充气即建立巡游模式并开始觅食,摄食比率迅速达到100%,其混合营养期仅有4h.实验期间,投喂组仔鱼的摄食比率一直保持在100%;饥饿组仔鱼在饥饿0-3d内初次摄食比率同样可达到或接近100%,但第4天开始下降,第6天初次摄食比率降至0,抵达饥饿不可逆点(PNR)时间为产出后第5.5天左右.投喂组初产仔鱼对1-2龄期库蚊幼虫的摄食强度为(2.9±1.4)ind/individual·h,摄食强度随日龄显著增长;饥饿组仔鱼在饥饿0-5d内其初次摄食强度也随日龄及饥饿时间的延长显著增长,但均显著低于相应日龄的投喂组仔鱼,其初次摄食比率与初次摄食强度之间并无显著相关关系.饥饿仔鱼在PNR前约1.5d时其累计死亡率已超半数,达(64.4±18.1)%,抵达PNR后数小时内残存个体全部死亡.实验结束(6d)时投喂组仔鱼5项生长指标呈不等速增长,其中体重增长最为显著,瞬时增长率达0.0275/d,此时腹鳍发育基本完备,进入幼鱼期.而同期饥饿组仔鱼形态发育停滞,多项生长指标出现负增长,其中体高负增长最为明显,其瞬时增长率为-0.0511/d;体重次之,体长负增长则不甚明显.饥饿仔鱼在接近或处在PNR期时腹部萎缩呈弧形,体长/体高>5,而同期投喂组仔鱼体长/体高<4.5,两者差异显著,可作为鉴别饥饿仔鱼和健康仔鱼较理想的形态数量指标.     

曼氏无针乌贼耗氧率及溶氧胁迫对其体内酶活力的影响

采用Winkler法测定水中溶氧含量，通过比较对照呼吸室与试验呼吸室水中溶解氧含量之差确定曼氏无针乌贼耗氧率及窒息点，并在不同程度的溶氧胁迫下测定乌贼体内多种酶的活力变化.结果表明：曼氏无针乌贼耗氧率呈明显的“高-低-高-低”昼夜变化；耗氧率与水温(16 ℃～28 ℃)和光照(3～500 μmol·m^-2·s^-1)呈正相关，与pH值(6.25～9.25)呈负相关；随着盐度的升高(18.1～29.8)，乌贼耗氧率呈“高-低-高”变化，盐度为24.8时耗氧率最低；雌性乌贼耗氧率高于雄性.窒息点随乌贼的体质量增加而降低，平均体质量为(38.70±0.52) g的乌贼窒息点为(0.9427±0.0318) mg·L^-1.随着溶氧胁迫程度的增加，超氧化物歧化酶(superoxide dismutase, SOD)、过氧化氢酶(catalase, CAT)和过氧化物酶(peroxidase, POD)活力均先升后降，脂肪酶活力下降，蛋白酶活力呈“降-升-降”变化；乳酸脱氢酶(lactate dehydrogenase, LDH)活力呈先升后降趋势，但溶氧胁迫下的酶活力比正常时要高.     

饥饿胁迫对瓦氏黄颡鱼脂肪代谢的影响

在水温(25±2)℃条件下,对初始体重为(23.65±2.82)g的瓦氏黄颡鱼进行30d饥饿处理,于饥饿第0、第7、第15和第30天取样,分析了饥饿胁迫对瓦氏黄颡鱼的生长、体成分、脂肪酸组成和脂肪代谢相关基因表达的影响。结果表明:饥饿胁迫显著降低了瓦氏黄颡鱼肥满度、脂体比及肝体指数(P0.05)。肌肉脂肪含量也随着饥饿时间的延长而下降(P0.05)。肝脏中的饱和脂肪酸和肌肉中的单不饱和脂肪酸显著下降,而肝脏中多不饱和脂肪酸和单不饱和脂肪酸及肌肉中的多不饱和脂肪酸显著上升(P0.05)。此外,肌肉中的n-6和n-3及肝脏中的n-6多不饱和脂肪酸显著上升,而肝脏中的n-3多不饱和脂肪酸显著下降(P0.05),表明瓦氏黄颡鱼饥饿期间主要消耗饱和脂肪酸及单不饱和脂肪酸供能,保留多不饱和脂肪酸。饥饿胁迫15—30d,瓦氏黄颡鱼肝脏脂蛋白酯酶、肝酯酶及肉碱酰基转运酶m RNA表达显著高于对照组(0d)(P0.05),而脂肪酸结合蛋白及脂肪酸合成酶m RNA的表达显著低于对照组(P0.05),表明饥饿胁迫可能会促进肝脏脂肪分解供能,降低脂肪的生物合成。     

短期饥饿和再投喂对岩原鲤仔鱼生存生长以及RNA/DNA和RNA/蛋白质比率的影响(英文)

研究通过对岩原鲤仔鱼在饥饿和再投喂条件下其生存、生长率、RNA/DNA和RNA/蛋白质比率的测定,评估了仔鱼对饥饿的耐受能力和恢复能力。在(19.5±0.5)℃水温下,将岀膜后第16天的岩原鲤仔鱼随机分成6个组:1个持续投饲对照组,实验组分别禁食1、2、3、4、5d后再投喂,实验共进行10d。每天分别从各组取9尾鱼测定体重、体长、RNA、DNA、蛋白质含量。实验结果显示,饥饿处理组仔鱼存活率和以上各项生长指标均随饥饿时间的增加而下降,在恢复投喂后均表现不同程度的补偿生长,其中饥饿1、2、3d的仔鱼在恢复投喂后显示出完全补偿生长,几乎弥补了饥饿所产生的影响,平均终体重与对照组比较无显著差异。饥饿4、5d的仔鱼显示部分补偿生长,恢复投喂只少量减轻了饥饿的影响,平均终体重与对照组相比存在显著差异。饥饿1、2、3d的仔鱼和4、5d的仔鱼在恢复投喂后分别需要1—2d和4d时间才能达到与对照组无显著差异水平。仔鱼生长率变动范围从0.59%到8.00%WW/day,仔鱼RNA/DNA比率、RNA/蛋白质比率与生长率的回归方程为:GR=3.63RNA/DNA 1.74(R2=0.80)和GR=120.14RNA/Protein 2.33(R2=0.31),两种比率均与生长率呈显著线性相关,RNA/DNA比率对生长变化的拟合度更好。结果表明,仔鱼阶段食物缺乏很可能是影响岩原鲤仔鱼存活、生长的主要因素。RNA/DNA更适合作为评定岩原鲤仔鱼营养条件和生长的指标。     

曼氏无针乌贼神经肽sCAP基因克隆与组织表达定位

为研究曼氏无针乌贼(Sepiella japonica)小心激肽(small cardioactive peptides, sCAP)生理功能, 通过RACE技术克隆曼氏无针乌贼sCAP基因(简称SjsCAP, GenBank登录号:MG779491), 得到总长度为696 bp的cDNA序列, 包括111 bp的5′非编码区(UTR)和324 bp的3′UTR, 预测的开放阅读框(ORF)共261 bp, 编码86个氨基酸, 相对分子量(MW)为9.331 kD, 等电点(pI)为8.52。信号肽以及跨膜区预测结果表明, sCAP中含有明显的信号肽序列和跨膜区结构。因此, 推测该蛋白可能由细胞内分泌到细胞外发挥作用。亲水性分析显示该蛋白为亲水性蛋白。基于sCAP氨基酸序列进行的系统进化分析表明曼氏无针乌贼与商乌贼(Sepia officinalis)亲缘关系最近, 相似性达到90%。通过荧光定量PCR (Quantitative real-time PCR, qRT-PCR)技术对SjsCAP基因在成熟雄性和雌性曼氏无针乌贼不同组织中的表达量进行分析, 结果显示sCAP主要在视叶中显著表达, 在脑中也有较高的表达量, 其中雄性个体表达量显著高于雌性个体。原位杂交实验结果显示sCAP基因在曼氏无针乌贼的脑组织的视叶、食道上神经团的垂直叶、亚垂直、脑脚叶、背外侧叶和视腺均可以观察到明显的阳性杂交信号。sCAP基因的成功克隆以及组织表达定位分析为sCAP的亚细胞定位以及生物学功能研究奠定一定的基础, 同时为曼氏无针乌贼的种质资源保护与开发提供一定的理论支持。     

Photoregulation of seed germination of wild-type and of an aurea-mutant of tomato

Seed germination of an aurea mutant of tomato ( Lycopersicon esculentum Mill.) is promoted by continuous irradiation with red, far-red or long-wavelength far-red (758 nm) light as well as by cyclic irradiations (5 min red or 5 min far-red/25 min darkness). Far-red light applied immediately after each red does not change the germination behaviour. Seed germination of the isogenic wild-type, cv. UC-105, is promoted by continuous and cyclic red light while it is inhibited by continuous and cyclic far-red light and by continious 758 nm irradiation. Far-red irradiation reverses almost completely the promoting effect of red light. The promoting effect (in the aurea mutant) and the inhibitory effect (in the wild-type) of continuous far-red light do not show photon fluence rate dependency above 20 nmol m⁻² s⁻¹. It is concluded that phytochrome controls tomato seed germination throgh low energy responses in both the wild type and the au mutant. The promoting effect of continuous and cyclic far-red light in the au mutant can be attributed to a greater sensitivity to P_fr.     

六种藓类植物茎的比较解剖学研究

通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.     

真菌类遗传学分析的知识结构教学

本文以认知结构理论为指导,讨论了真菌类遗传分析与高等动植物遗传分析的内在联系,认为利用这种内在联系进行教学可收到好的效果并说明了作者的具体教学过程。 Abstract:In the paper, the relationship between genetic analysis of Fungi and genetic analysis of high animal and plant was discussed.A good results were obtained when we adopted this method in the teaching.     

Interconnection of parameters of regulation system of lipid peroxidation and of morphophysiological parameters of mouse liver

A complex analysis of seasonal fluctuations of the mean group parameters of the system of regulation of lipid peroxidation has been performed in liver of Balb/c mice. Association of lipid characteristics and morphophysiological parameters is studied in the Balb/c mouse liver. An inter-connection is revealed between the liver index and the amount of lysoforms of phospholipids, the scale and character of the interconnection differing essentially depending on proportion of phos-phatidylcholine in mouse liver phospholipids.     

History of the discovery of the mode of transmission of yellow fever virus

This essay documents and examines the historical circumstances and events surrounding the discovery of the mode of transmission of yellow fever virus in Cuba. Close scrutiny of the articles published by Walter Reed and his colleagues in 1900, 1901 and 1902 reveals their limitations as historic documents. Fortunately, other sources of information from that period survive in letters and documents written by individuals involved in the quest for the mode of transmission. Examination and comparison of those sources of information unveiled a fascinating story which reveals that misunderstandings engendered by published articles accorded merit where it was not fully due.     

Physiological characteristics of various species of strains of carboxydobacteria

Seven strains of aerobic carbon monoxide-oxidizing bacteria (carboxydebacteria) when growing on CO as sole source of carbon and energy had doubling times which ranged from 12–42 h. The activity profiles obtained after discontinuous sucrose density gradient centrifugation indicated that the CO-oxidizing enzymes are soluble and the hydrogenases are membrane-bound in all strains examined. The CO-oxidizing enzymes of Pseudomonas carboxydohydrogena, Pseudomonas carboxydoflava, Comamonas compransoris, and the so far unidentified strains OM2, OM3, and OM4 had a molecular weight of 230,000; that of Achromobacter carboxydus amounted to 170,000. The molecular weights of the CO-oxidizing and H₂-oxidizing enzymes turned out to be identical. The cell sonicates were shown to catalyze the oxidation of both CO and H₂ with methylene blue, thionine, phenazine methosulfate, toluylene blue, dichlorophenolindophenol, cytochrome c or ferricyanide as electron acceptors. Methyl viologen, benzyl viologen, FAD⁺, FMN⁺, and NAD(P)⁺ were not reduced. The spectrum of electron acceptors was identical for all strains tested. Neither free formate, hydrogen nor oxygen gas were involved in the CO-oxidation reaction. Methylene blue was reduced by CO at a 1:1 molar ratio. The results indicate that CO-oxidation by carboxydobacteria is catalyzed by identical or similar enzymes and that the reaction obeys the equation CO+H₂OCO₂+2H⁺+2e^- as previously shown for Pseudomonas carboxydovorans.Dedicated to Otto Kandler remembering almost three decades of enjoyable cooperation     

Modulation of allostery of pyruvate kinase by shifting of an ensemble of microstates

Since the introduction of the concepts of allostery about four decades ago, much advancement has been made in elucidating the structure-function correlation in allostery. However, there are still a number of issues that remain unresolved. In this review we used mammalian pyruvate kinase (PK) as a model system to understand the role of protein dynamics in modulating cooperativity. PK has a triosephosphate isomerase (TIM)(α/β)₈ barrel structural motif. PK is an ideal system to address basic questions regarding regulatory mechanisms about this common (α/β)₈ structural motif. The simplest model accounting for all of the solution thermodynamic and kinetic data on ligand-enzyme interactions involves two conformational states, inactive E^T and active E^R. These conformational states are represented by domain movements. Further studies provide the first evidence for a differential effect of ligand binding on the dynamics of the structural elements, not major secondary structural changes. These data are consistent with our model that allosteric regulation of PK is the consequence of perturbation of the distribution of an ensemble of states in which the inactive E^T and active E^R represent the two extreme end states. Sequence differences and ligands can modulate the distribution of states leading to alterations of functions. The future work includes: defining the network of functionally connected residues; elucidating the chemical principles governing the sequence differences which affect functions; and probing the nature of mutations on the stability of the secondary structural elements, which in turn modulate allostery.     

（鱼句）亚科花（鱼骨）型鱼类骨骼系统的比较

对我国花型Hemibarbuspattern鱼类作了骨骼系统比较,结果表明,此类型鱼类脑颅较长,副蝶骨平直或稍弯曲,眶蝶骨腹纵嵴发达(铜鱼Coreius septentrionalis例外),下颞窝和咽突中等大,基枕骨后突发达;脑颅中的上筛骨的后突、侧筛骨的外筛突,蝶耳骨的外突、上耳骨的后突、围眶骨和后颞窝等均有明显的差异;咽颅中的舌颌骨、尾舌骨、鳃盖骨和下咽齿的列数等又有显著的区别;附肢骨骼中的腰带骨、脊椎骨中的复合神经骨和第4椎骨腹侧的悬器等也有不同之处。据此,这些差异和区别可作为属间或种间的分类依据。