盐度对条石鲷胚胎发育的影响

为了确定条石鲷胚胎孵化的适宜盐度,在试验水温为23.0℃～25.2℃条件下,设置了8个盐度组进行条石鲷胚胎孵化试验,研究了盐度对条石鲷胚胎发育的影响。结果表明:低盐度和高盐度对胚胎有持续性伤害,均可造成胚胎和卵黄球在卵裂期收缩而死亡,一部分胚胎在原肠期之后收缩死亡;低盐度可造成初孵仔鱼畸形率增加,主要引起仔鱼脊柱"L"形和"C"形弯曲,而高盐度可导致胚体胚孔关闭以后尾部的畸形发育;通过分析各盐度组的孵化率、仔鱼畸形率和盐度之间的关系,得出健康仔鱼比例(PHL)和盐度(S)的关系式为PHL=-0.0018S2-0.1135S-0.8853(R2=0.948),以PHL70%为适宜孵化盐度范围,以PHL90%为最适孵化盐度范围,由此确定在23.0℃～25.2℃条件下,条石鲷的适宜孵化盐度范围为21～42(PHL70%),最适为30～33(PHL90%)。     

盐度及pH对星斑裸颊鲷受精卵孵化和仔鱼耐饥饿能力的影响

比较观察了不同盐度(0、5‰0、10‰、15‰、20‰、25‰、30‰、35‰、40‰和45‰)及不同pH(5.5、6.0、6.5、7.0、7.5、8.0、8.5、9.0和9.5)条件下,星斑裸颊鲷(Lethrinus nebulosus)受精卵的孵化时间、孵出期、孵化率、畸形率及一定时间内(24h和48h)仔鱼成活率,并且在以上盐度和pH条件下对星斑裸颊鲷初孵仔鱼进行耐饥饿试验,测定其不投饵存活指数(survival activity index,SAI).结果表明,只有SAI值大于3的星斑裸颊鲷仔鱼才有可能被进一步培育成苗,低于3的将在数天内死亡;星斑裸颊鲷受精卵孵化的适宜盐度范围是10‰～45‰,最适宜盐度范围15‰～40‰,适宜pH是6.5～9.0,最适宜pH范围7.0～8.5;初孵仔鱼生存的适宜盐度范围是10‰～40‰,最适宜盐度范围20‰～25‰,适宜pH是5.5～9.5,最适宜pH范围7.0～8.5.     

盐度对新吉富罗非鱼受精卵孵化和仔稚鱼活力的影响

研究了盐度梯度对新吉富罗非鱼(Oreochromis niloticus)受精卵孵化和仔鱼活力的影响。水温(28±0.5)℃下,观察比较了8个梯度的盐度(3‰、6‰、9‰、12‰、15‰、18‰、21‰、24‰)及纯净淡水(盐度为0)条件下,新吉富罗非鱼受精卵的孵化时间、孵化周期、孵化率和畸形率。同时在不同盐度条件下对4批初孵仔鱼进行耐饥饿实验,测定其不投饵存活系数(SAI)值。结果表明,新吉富罗非鱼受精卵在盐度6‰～15‰时,孵化率较高(89.0%～92.7%);盐度低于3‰和高于18‰时,孵化率较低。仔鱼生存适宜盐度3‰～15‰,最适盐度6‰～9‰。新吉富罗非鱼仔鱼在盐度0～3‰及18‰～24‰时,仔鱼的SAI值较低,不适宜仔鱼培育;盐度为6‰～15‰时,仔鱼的活力较高。仔鱼的SAI值与受精卵的孵化率呈正相关关系。     

四指马鲅(Eleutheronema tetradactylum)受精卵和仔鱼对不同盐度的耐受性

本文观察了11个盐度梯度(5、7、9、11、13、15、20、25、28、30、35、40、45,28作为对照组)下四指马鲅(Eleutheronema tetradactylum)不同发育阶段的受精卵的沉浮性质和孵化情况以及初孵仔鱼在不投饵条件下的存活情况,并测定不投饵存活系数(survival activity index,SAI)。结果表明:第一次分裂前和原肠期两发育阶段的受精卵在盐度低于25的海水中均呈沉性,盐度为25时则悬浮在水层中部,盐度28及以上呈浮性;第一次分裂前的受精卵对盐度改变较敏感,而原肠期受精卵对盐度胁迫产生一定的耐受性;盐度的改变对初孵仔鱼的存活率和SAI值影响比较大。综合分析孵化率、仔鱼畸形率以及SAI值,推测四指马鲅受精卵孵化的适宜盐度范围为25~35,最适孵化盐度为35。     

条石鲷的早期生长发育特征

对条石鲷(Oplegnathus fasciatus)早期生活史阶段生长发育特征进行了观察和测量,描述了胚胎和胚后各发育阶段的生长发育特征。条石鲷成熟卵子为浮性、端黄卵,卵径0.86mm±0.012mm(n=30),单油球,油球径0.18mm-0.22mm。在水温23.5℃±0.5℃、盐度30.5、pH8.0-8.3条件下,受精卵经27.5h孵化出膜。初孵仔鱼消化道细而直,随着仔鱼发育,消化道变得粗大、弯曲,肠道内褶回增多,消化能力增强。3日龄(仔鱼孵化出膜后第一天称为0日龄,以此类推)仔鱼卵黄囊消耗殆尽,开口,肛门与外界相通,油球在6日龄消耗完毕,进入外源性营养阶段。仔稚鱼培育在室内水泥池进行。在水温21℃-24℃、盐度27-33、pH8.0-8.3条件下,仔鱼开口饵料为S型褶皱臂尾轮虫,4日龄仔鱼开始摄食轮虫或轮虫卵,13日龄开始摄食卤虫无节幼体,25日龄开始进行配合饲料转化,30日龄后苗种摄食配合饲料良好。4日龄仔鱼鳔原基形成,7日龄时鳔开始充气变为亮泡状,生活史终生有鳔。色素细胞首先出现在12h50min的胚体上,至18h已在胚体全身分布,随着胚体发育,色素细胞增多。脊椎骨末端弯曲在15日龄开始,至24日龄弯曲过程完成,除腹鳍外其它鳍的鳍条数与成鱼一致,牙齿(硬齿和绒毛齿)生成,可咬食饵料。体表七条横向黑色素带是条石鲷的一个显著体态特征。21日龄鱼体表形成第一条横向黑色素带,23日龄时体表形成第二条色素带,25日龄时形成第三条色素带,29日龄时仔鱼体表第五条色素带形成,至40日龄时第七条色素带形成,此时稚鱼体态除背鳍、尾鳍、腹鳍上色素外与成体相似。60日龄幼鱼鳞片形成,在体态上与成体无明显区别。     

日本鬼鲉胚胎发育及仔、稚鱼形态学观察

对日本鬼鲉的胚胎及仔稚鱼形态发育进行观察,描述了各发育时期的发育时序和形态特征。日本鬼鲉的受精卵呈正圆球形,无色透明,无油球,平均卵径为(1.42±0.04)mm,呈浮性。在水温(22±0.5)℃,盐度31‰的条件下,历时约52h10min完成孵化。初孵仔鱼全长(3.04±0.13)mm,卵黄囊长(2.23±0.08)mm,卵黄囊高为(1.65±0.06)mm,在(21±0.5)℃水温下,仔鱼孵化后3d内营内源性营养(卵黄囊仔鱼),第4天卵黄囊完全消失,开口摄食轮虫。13d全长(7.12±0.35)mm,背鳍鳍条出现进入稚鱼早期,15d全长(7.92±0.61)mm鱼体及各鳍开始出现金黄色斑纹,25d全长(13.66±0.55)mm,整个鱼体呈黄褐色,完成变态进入幼鱼期,开始营底栖生活。同时观察了自胚胎发育至幼鱼期鱼苗体表色素分布的变化及其器官发育的形态变化。     

盐度对军曹鱼胚胎和仔鱼发育的影响

观察比较了不同盐度梯度(20、23、26、29、32、35、38、41和44)下军曹鱼受精卵的沉浮性、孵化率和畸形率以及测定了不同盐度梯度(10、14、18、22、26、30、34、38、42和44)下仔鱼不投饵存活系数SAI值。结果表明,受精卵在海水盐度32以上为完全浮性,26以下为完全沉性。军曹鱼受精卵孵化的最适盐度范围为29～38,适宜盐度范围为26～41,其中23～26和41～44分别视为受精卵孵化在低盐区和高盐区的两个临界区域,在此盐度上下,军曹鱼受精卵孵化率大幅度下降而仔鱼畸形率大幅度上升。试验盐度范围内军曹鱼仔鱼SAI值为2.32～16.24,仔鱼生长和存活的最适盐度范围为26～34,适宜盐度范围为22～38,而盐度18～22及38～42可分别视为军曹鱼仔鱼存活率在低盐区和高盐区的两个临界区域。     

牛蒡抗虫活性及抗虫成分的初步研究

在水温(23±0.5)℃、pH 7.0～8.0、溶解氧＞5 mg· L-1的条件下,研究孵化过程中不同盐度对拟目乌贼胚胎发育和孵化率的影响.结果表明,拟目乌贼卵透明略带奶油色,近椭圆形,短径为0.596～1.758 cm,长径为1.452～3.136 cm,刚产出的卵重约2g;孵化完成时,卵膜内的重量达到4.5g.在盐度为28‰时,经过28～30 d孵化,卵的短径和长径平均分别增加了0.601、0.615 cm,孵化率为57.0％;盐度为23‰时,卵的长径和短径也相应增加,增幅分别为0.567、1.263 cm,孵化率为13.5％;盐度为33‰时,经过28～30 d孵化,卵短径平均增长0.150 cm,而长径却缩短了0.141 cm,孵化率为9.5％;在盐度为13‰、18‰、38‰和43‰条件下,胚胎停止发育,孵化率为0.结果表明,拟目乌贼属于狭盐性种类,盐度变化对拟目乌贼胚胎发育和孵化有直接影响.     

东湖茶港排污口底泥对稀有鮈鲫的毒性

以东湖茶港排污口底泥复溶水为试验相,采用96h急性毒性试验和胚胎—卵黄囊吸收阶段毒性试验方法,研究了东湖茶港排污口底泥对稀有的鮈鲫毒性。结果显示,高浓度的复溶水对稀有鮈鲫胚胎、仔鱼和幼鱼具有明显的毒性效应,而胚胎—卵黄囊吸收阶段更为敏感。随着复溶水浓度的增加,稀有鮈鲫受精卵孵化率降低,仔鱼畸形率增高、成活率降低、生长减慢;对胚胎—卵黄囊吸收阶段的NOEC、LOEC和MATC分别为12.5%、25%和17.68%;对幼鱼96h LC50为69.1%。本文的研究还表明,底泥经晾晒后毒性大幅降低,暗示恢复东湖通江状态并让水位自然涨落,可能有助于缓解污染、恢复生态环境。     

东湖茶港排污口底泥对稀有

以东湖茶港排污口底泥复溶水为试验相,采用96h急性毒性试验和胚胎-卵黄囊吸收阶段毒性试验方法,研究了东湖茶港排污口底泥对稀有(鱼句)鲫的毒性.结果显示,高浓度的复溶水对稀有(鱼句)鲫胚胎、仔鱼和幼鱼具有明显的毒性效应,而胚胎-卵黄囊吸收阶段更为敏感.随着复溶水浓度的增加,稀有(鱼句)鲫受精卵孵化率降低,仔鱼畸形率增高、成活率降低、生长减慢;对胚胎-卵黄囊吸收阶段的NOEC、LOEC和MATC分别为12.5%、25%和17.68%;对幼鱼96h LC50为69.1%.本文的研究还表明,底泥经晾晒后毒性大幅降低,暗示恢复东湖通江状态并让水位自然涨落,可能有助于缓解污染、恢复生态环境.     

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。