尖前口虫的口器发生研究(纤毛门, 膜口目)

研究了咽膜类纤毛虫尖前口虫无性生殖期的核器及口器的演化.其发生特征为;1)新的口原基形成于原前庭动基列与口侧膜间,表观为原口侧膜分裂而致;2)随着形态发生的进行,由口原基依次演化出后仔虫的三片咽膜、口侧膜和三条前庭动基列;3)原口器完全被前仔虫所继承;4)体纤毛器在整个形态发生过程中一直保持双动基列结构.       

钩刺亚册虫的光镜和扫锚电镜观察

作者对钩刺亚册虫的纤毛器的形态结构做了光镜和电镜水平的研究,结果表明：口侧动基索均为单动基列结构,其中ＰＫ１仅后行至胞口后方;背触毛含约１０对紧密排列的毛基体,后端不与其它体动基列相联;射出体除沿胞口分布外,在虫体顶端丛集成盾;虫体前部自右向左扭转约１８０＾ｏ。     

钩刺亚册虫的光镜和扫描电镜观察

作者对钩刺亚册虫（Ａｃｉｎｅｒｉａｕｎｃｉｎａｔａ）的纤毛器和形态结构做了光镜和电镜水平的研究,结果表明：口侧动基索均为单动基列结构,其中ＰＫ１仅后行至胞口后方;背触毛含约１０对紧密排列的毛基体,后端不与其它体动基列相联;射出体除沿胞口分布外,在虫体顶端丛集成盾片状;虫体前部自右向左扭转约１８０°。     

云南臭蛙的分类学研究 (无尾目：蛙科)

作者采用形态特征比较、标准判别分析方法和DNA批纹技术对云南臭蛙Odorrana andersonii9个居群进行了综合研究,结果表明：9个居群可以分为以云南龙陵、景东、海南标本为代表的3个形态型,它们的形态特征差异明显;3者的标准判别分析和DNA指纹图谱结果均有明显不同,印证了形态性状研究结果。据此上述3个形态型标本被确定为3个种,其中包括2新种,本文对原隶属于云南臭蛙的各地标本的分类地位作了讨论。     

六种淡水纤毛虫形态学研究

借助活体观察和银染法对6种淡水纤毛虫(纵长板壳虫Coleps elongatus、瓜形原膜袋虫Protocyclidiumcitrullus、亨氏累枝虫Epistylis hentscheli、钟形钟虫Vorticella campanula、长柄球吸管虫Metacineta macrocaulis、四分锤吸管虫Tokophrya quadripatita)的形态和纤毛图式进行了详尽研究。本工作首次描述了亨氏累枝虫、四分锤吸管虫、纵长板壳虫的中国种群,同时揭示了亨氏累枝虫长期未知的纤毛图式特征并给出该种类的新定义: 虫体高钟形,活体大小约(100-130) m(60-65) m; 伸缩泡1个,腹位; 大小核各1枚,大核C型; 群体为规则对称二叉分枝; 口区三片小膜均由三列动基列组成,第三小膜由三列等长的动基列组成,其终止处高于第一小膜下端; 虫体前端到反口纤毛环间的银线约71-74条,反口纤毛环到帚胚间的银线约35-47条; 淡水生境。此外,本研究对长柄球吸管虫、钟形钟虫、瓜形原膜袋虫进行了重新描述,补充了显微照片。     

中国蛙科一新种——版纳大头蛙(两栖纲:无尾目)

经核查和鉴定中国云南等地原定名为大头蛙[Limnonectes kuhlii(=Rana kuhlii Tschudi,1838)]的标本及相关文献资料,并与产地为印度尼西亚的爪哇大头蛙(Limnonectes kuhlii)模式标本的有关描述相对比,两者在其形态、染色体及线粒体基因分化等特征上均有明显区别,因此将云南、广西等地标本的种名改订为新种,即版纳大头蛙(Limnonectes bannaensis,sp.nov.)。其主要鉴别特征是:1)背面较光滑,具少数细肤棱,体后部有小圆疣;2)体背面浅褐色或灰褐色,肤褶上有黑纹;3)蝌蚪尾部具深色斑纹,但尾后半段不呈黑色;4)其染色体组型为2n=22(20m 2st)。而爪哇产大头蛙:1)背面粗糙,体背部、胫部和肛部周围满布圆形疣粒;2)体背面为黑大理石色或为黑色;3)蝌蚪尾部后半段为黑色;4)染色体组型为2n=26,5对大染色体,8对小染色体,除第8对为亚端部着丝粒外,其余均为中部和亚中部着丝粒。     

中国四川省蛙科一新种——南江臭蛙(两栖纲:无尾目)

对分布于四川、重庆市、贵州、湖北、湖南、安徽和福建的花臭蛙[Odorrana(Odorrana)schmackeri(Boettger,1892)]标本进行了形态比较,结果发现四川省南江和万源县的花臭蛙标本与其他产地的花臭蛙标本在形态特征上存在明显区别,主要是:1)成体雄雌体长之比值较小,约为1∶1.34;2)犁骨齿列短,两内侧间距宽,距内鼻孔远;3)背面深色斑点周围无浅色边缘;4)股后部深色斑大而稀疏;5)趾间蹼较弱,第四趾蹼达远端关节下瘤;6)腹内成熟卵的动植物极均为乳白色。故将四川省南江和万源的标本订为新种--南江臭蛙[Odorrana(Odorrana)nanjiangensis,sp.nov.]。     

太行隆肛蛙补充描述(无尾目,蛙科)

对采自我国河南济源市邵原镇太行山的隆肛蛙标本进行了形态学观察分析,发现该地标本在形态上与模式产地巫山隆肛蛙标本及其它种群存在明显差异,这表明太行山的隆肛蛙应是一独立种,即太行隆肛蛙Paa(Feirana)taihangnicus.本文对该种进行了详细的记述,并依据遗传学资料做了相应的分类讨论.     

无指盘臭蛙体内寄生双睾虫属多盘吸虫一新种

于云南一平浪镇无指盘臭蛙Rana grahami Boulenger膀胱内检获单殖吸虫多盘科双睾虫属l新种,以宿主名命名为无指盘臭蛙双睾虫Diplorchis grahami sp. Nov..检查36只无指盘臭蛙,感染率为19.4%,感染虫体1～94枚,平均感染强度为31,相对密度为6.02.新种模式标本具有典型双睾属多盘吸虫的特征:消化道两侧均未形成肠盲突,末端不形成联合,不延伸进入后吸器.阴道孔隆起明显,子宫具升支和降支,向后延伸至后吸器内.卵黄腺发达,滤泡状,沿肠管两侧分布至后吸器内.生殖棘7枚排列为冠状.本双睾虫体长平均4.627 mm,虫体最宽处平均1.611mm,与黑斑蛙双睾虫、拉氏双睾虫和杭州双睾虫均属于大型虫体,但新种的几丁质结构与上述3种已记录的双睾虫存在显著差异,其后吸器相对较小,平均为0.681 mm×1.178mm,吸盘直径平均284.22μm,大钩较小,平均295.87μm,X/Y为1.255;但与小型的石林双睾虫比较,大钩X/Y值差异不显著.     

钩刺斜管虫无性生殖期间的口纤毛器及细胞发生研究（原生动物：纤毛虫）

钩刺斜管虫口和体纤毛器演化模式是研究该类动物个体发生的优秀模型。通过跟踪研究,澄清了后仔虫口器发生以及体纤毛器起源上的几点疑问,并证实：体左侧二列片段动基列为同源再造而非来自老结构的分裂或复制;三列围口纤毛均为双动基列构造;后仔虫口原基场的构建系由５列体动基列共同参与完成的,其中最左侧两列短的原基片段与原基１整合为一体,从而发展成营养期虫体的外围口动基列;后仔虫背触毛原基为独立发生。     

微囊藻对柔细束丝藻生长及土臭素合成与释放的影响

文章选择两种特征不同的微囊藻——产毒的铜绿微囊藻(Microcystis aeruginosa)和无毒的惠氏微囊藻(Microcystis wesenbergii),分别以不同的接种比例(1﹕2、1﹕1和2﹕1)与产土臭素(Geosmin)的柔细束丝藻(Aphanizomenon gracile)混合培养,以探索种间相互作用对藻类生长和束丝藻土臭素合成与释放的影响。结果表明,在共培养条件下,两种微囊藻均抑制了柔细束丝藻的生长,而柔细束丝藻却促进了两种微囊藻的生长。惠氏微囊藻促进了柔细束丝藻土臭素的释放(接种比例为1﹕1时,束丝藻胞外土臭素的细胞份额达到269.43 fg/cell),仅在生长早期与生长受到抑制阶段促进了土臭素的合成;铜绿微囊藻在共培养早期促进了束丝藻土臭素的合成,但共培养却抑制了土臭素的释放,而且在共培养的中后期已检测不到土臭素。研究结果表明,在自然水体中束丝藻与微囊藻的季节演替过程中,微囊藻在与束丝藻的竞争中处于优势,且微囊藻对束丝藻的竞争压力促使后者合成异味物质,随着束丝藻的消亡可能伴随大量异味物质的释放,增加异味事件发生风险。     

Cellularisation: les opalines illustrent-elles une tentative de constitution d'un être pluricellulaire ?

According to their state of evolution the opalinids trophozoits are bi- or multinucleate, all the nuclei beying genetically equivalent. Therefore, they are not typical protists but more or less complex syncitia. The reproductive cycle includes a sexual phase, host dependent. During gametogenesis the cells divide without previous nudear division. They become smaller and differenciate as uninuclear gametes. After fertilization the new trophozoits grow and multiply their nuclei, cytokinesis being inhibited during a some times. As the first stage of the Drosophila embryo, they become syncitia. In this pluricellular organism, the nuclei migrate in the cortex before cell wall construction and it was demontrated that microfibrills and associated proteins are implicated in this mechanisms. So, it is possible that, in opalinids, the same cytoskeleton components, linking the nuclei to the cortex and targets of external signal, regulate the caryokinesis and the cytokinesis. The data of a comparative study of bi- and multinucleate species of opalinids agree with this hypothesis. A deficiency or a delay in this coordinating mechanism may induce the formation of a syncitium. So, opalinids may be held as an attempt to realize pluricelular organisms.     

Intensive nuclear selection in tryptophan limited cultures of Escherichia coli B/r/l, trp

Summary The paradoxical constancy of the rate of mutation to resistance to bacteriophage T5 was observed long ago by Novick and Szilard. Mutation rates are independent of growth rate in tryptophan limited chemostat cultures, even though both average cell volume and DNA content increase with generation time. To examine nuclear selection in these multinucleate cells, cultures of E. coli B/r/l, trp were exposed briefly to acridine orange/visible light, and cells repackaged to uninucleate forms by shifting growth rates up to 0.5 divisions per hr. The kinetics of accumulation of mutant nuclei indicates that only a single master nucleus replicates in each cell, one of its progeny becomes the master nucleus during the following nuclear generation in the same cell, and both progeny become master nuclei if the cell divides. Autoradiographs showed that master nuclei are located at the ends of cells and that uninucleate cells are produced at each division, except possibly for a small fraction of aberrant divisions. This intensive selection during replication and inheritance of master nuclei provides an explanation for the constancy of cellular mutation rates, which is due to the constancy of the rate of DNA replication in these cultures and the (almost) complete selection for mutant nuclei in mutated cells.Work supported by the U. S. Atomic Energy Commission.     

Pattern of DNA synthesis in nuclei of feeding and starving Amoeba proteus : A cytofluorometric study

The DNA content in isolated nuclei of Amoeba proteus was determined for each of the three groups of synchronized amoebae over different intervals after division. Several nuclei of each amoeba group were fixed 1 h after division, before the amoebae were fed. About h after division, some amoebae in each group were given food (Tetrahymena pyriformis), while the rest were left starving. Samples of the nuclei of fed and starved amoebae were fixed 24 h and (in different groups) 42–55 h after division. In each group from 22 to 48% of the fed amoebae had divided prior to the last nuclei fixation. Starved amoebae did not undergo division. In all three amoeba groups the nuclear DNA content of fed cells by the end of interphase had increased to 280–300% the value for 1 h amoebae. The nuclear DNA content of starved amoebae of all three groups was also increased, and in two groups it exceeded the initial level more than two-fold. However, in all three groups, it was lower than that of fed amoebae. In all the groups the nuclear DNA content in fed amoebae grew after 24 h, i.e. during the second half of interphase, the increase accounting for from 11 to 48% of the total increase. The hypothesis is put forward that the increase in the nuclear DNA content during the cell cycle of Amoeba proteus is the result of two processes: (1) one-time replication of the DNA of the whole genome; and (2) repeated replication of some part of the DNA. In amoebae the relation of the pattern of nuclear DNA synthesis to the diet is considered.     

The Binary Fission of Lacrymaria olor (O.F.M., 1786).

SUMMARY. Observations on binary fission of Lacrymaria olor show that it is a transverse fission. It involves probable intranuclear division of the micronucleus. Both micro- and macronucleus elongate in preliminary stages. Each is ultimately divided as cytoplasmic constriction cuts the spindle fibers of the former, and the connecting, nucleoplasmic thread of the latter.
Surging movements of cytoplasm after fission elongate the daughter organisms and move new nuclei to normal, central sites. The anterior proboscis of the posterior daughter regenerates suddenly, complete with coronal cilia. Metachronal waves along ciliary meridians, strongly reversed on the posterior daughter, cause an oscillating movement which pulls the two apart, except for a slender, pellicular thread, ultimately severed. Until broken, this thread connects the rear tip of the anterior animal to the forward end of the proboscis of the posterior one. The organism is semi-quiescent, with proboscis retracted (except spasmodically) throughout fission. After fission the anterior animal quickly begins feeding movements and soon swims away. The posterior animal requires about half an hour before being able to begin feeding and swimming movements.
The anterior contractile vacuole of the original animal becomes the primarily active vacuole of the anterior daughter; the posterior one that of the posterior daughter. Missing vacuoles are regenerated by the daughters in about one hour after fission. The division process requires about one hour for completion at 22.4°C.     

Light and electron microscopic studies of meiosis in the basidia ofPholiota terrestris

Summary The two division of meiosis that occur in the distal portion of the basidia ofPholiota terrestris were studied with light and electron microscopy. A diglobular spindle pole body (SPB), consisting of two globular elements and a connecting, electron-dense middle piece, is closely attached to the nuclear envelope of the fusion nucleus. During prometaphase I the globular elements separate and pass to the opposite poles as the chiastic spindle is formed. Evidently, the middle piece also separates with each resulting half persisting as an eccentric, electron-dense portion of the monoglobular SPB of meta-, ana-, and telophase nuclei. Also during prometaphase I, the nuclear envelope becomes discontinuous, especially in the lower region of the spindle. Light microscopic evidence of nucleolar extrusion at prometaphase I and II was observed. At metaphase I the SPB's move away from the condensed chromatic mass as the chromatids move asynchronously along the expanding spindle, evidently, due both to the elongation of the continuous fibers and the shortening of the chromosomal fibers. Two images resembling typical kinetochroes are illustrated in anaphase I nuclei, and others were seen during the study. At early telophase I and II the nuclear envelope is present laterally, is then formed in the interpolar region, and eventually appears between the chromatin and monoglobular SPB. A perforated ER cap, which is penetrated by microtubules, delimits the SPB. The nucleus enlarges, the chromatin becomes diffused except adjacent to the SPB, and the perinuclear ER becomes uniformly oriented around the nuclear envelope. At interphase I a diglobular SPB was not clearly documented. During interphase I the ER cap disappears but the perinuclear ER persists. Division II, with the exception of prophase, is essentially identical to division I. The postmeiotic, haploid nuclei migrate to the median or proximal region of the basidium. The diglobular SPB reappears. The meiotic apparatus inP. terrestris is considered to have the same fundamental features as those of plants and animals and in detail conforms to the pattern described in several light and electron microscopic studies of other Homobasidiomycetes.     

Significance of peristaltic squeezing of sperm bundles in the silkworm, Bombyx mori: elimination of irregular eupyrene sperm nuclei of the triploid

Silkworm (Lepidoptera) males produce dimorphic sperm: nucleate eupyrene sperm and anucleate apyrene sperm. The eupyrene sperm are ordinary sperm to fertilise the eggs, while the function of apyrene sperm remains uncertain. After meiosis, 256 sperm cells are enclosed by a layer of cyst cells, forming a sperm bundle. We have previously documented that the nucleus of eupyrene sperm anchors to the head cyst cell, which locates at the anterior apex of the bundle, by an acrosome tubule-basal body assembly. Neither the basal body attachment to the nucleus nor the acrosome is seen in apyrene sperm, and the nuclei remain in the middle region of the bundle. Peristaltic squeezing starts from the anterior of the bundles in both types of sperm, and cytoplasmic debris of the eupyrene sperm, and both the nuclei and debris of apyrene sperm, are eliminated at the final stage of spermatogenesis. Since the irregularity of meiotic division in apyrene sperm is known, we used triploid silkworm males that show irregular meiotic division even in eupyrene spermatocytes and are highly sterile. The irregular nuclei of the triploid are discarded by the peristaltic squeezing just as those of the apyrene sperm. Transmission electron microscopic observations disclose the abnormality in the acrosome tubule and in the connection to the basal body. The peristaltic squeezing of sperm bundles in the silkworm appears to be the final control mechanism to eliminate irregular nuclei before they enter female reproductive organs.     

Notes on african opalinids (Protozoa,Opalinata). I Zelleriella spp

Summary The features by which the body-form of a species of Zelleriella may be described are defined and compared with those of Opalina and Protoopalina. Z. africana Sandon: The two forms previously included under this name are re-examined, some developmental stages are described and the relationships between the two forms discussed. The following new species are described: Z. angusticeps from Bufo angusticeps Smith from Cape Town; two species from Nile fish, namely, Z. distichodi from Distichodus rostratus Gunther (Citharinidae) and Z. synodontis from Synodontis clarias (Linnaeus) (Siluridae). Two types of cyst are described, one small, usually mononucleate, and relatively thick-walled, the other much bigger, binucleate, thin-walled and ciliated. In Z. angusticeps separation of the two halves in cytokinesis begins at the posterior end of the body, the falx being the last part to divide. Such division is contrasted with the kind of interkinetal fission found in other opalinids and with the longitudinal fission of flagellates. The evidence that there are two types of longitudinal fission among the Zelleriellas is discussed. Life-cycles, geographical distribution and host relationships are also discussed. ac]19790807     

The Opalinid Infusorians: Flagellates or Ciliates?

SUMMARY. The controversial question of the affinities of the enigmatic opalinids is discussed in the light of recent findings and with regard for modern ideas concerning characters of most significance in the phylogeny of various major protozoan groups. Metcalf's "protociliate" hypothesis still retains a high popularity although many of the factors supporting it have been adequately disproven during the past 20 years. The "ciliate-" and "flagellate-like" characteristics of the Opalinidae are listed and reviewed.
Considered to be one of the most significant of mastigophoran features is the "symmetrigenic" mode of fission, a character generally disregarded in the past. Coupled with nuclear monomorphism and a syngamous reproductive cycle the type of division presents a very strong argument in favor of closer affinities with the zooflagellates than with the ciliates. It is stressed that the opalinids are highly differentiated forms, not likely primitive or ancestral for any major group of protozoa, which have had a long evolutionary history of their own. Grassé's recent erection of a new super-order in the Zoomastigophora to contain the family Opalinidae is defended and commended.     

Ultrastructure of meristematic cells of dormant and released buds in Tradescantia paludosa

The lateral bud meristems of Tradescantia paludosa show a characteristic cytohistological zonation during dormancy. The cells comprising this so called ‘zone of inhibition’, which is located at the extreme tip of the bud apex, rarely synthesize nuclear DNA or undergo mitotic division. These nuclei are as large as prophase nuclei, yet contain only telophase (2C) amounts of DNA and significantly lower amounts of histone as compared to the 2C nuclei of the actively dividing cells.Ultrastructural observations of the nuclei in the ‘zone of inhibition’ show that a large proportion of the chromatin is organized as less condensed, diffuse, euchromatin fibrils; however, the chromatin of the actively dividing nuclei of the cells outside the ‘zone of inhibition’ or in the released bud meristems is organized to a greater extent as condensed clumps of heterochromatin. When the dormancy is released, the nuclei in the ‘zone of inhibition’ synthesize DNA and histone and undergo cell division in approx. 4 days. Striking changes in the organization of chromatin fibrils take place during this transition period. The diffuse chromatin fibrils of the nuclei in the ‘zone of inhibition’ progressively become more and more condensed as the cell prepares to undergo the first mitotic division after the release of dormancy. This change which is coupled with the synthesis of histones in the nuclei of the ‘zone of inhibition’ suggests a prominent structural role of these basic proteins in the organization of the chromatin. The large volume of 2C nuclei of the ‘zone of inhibition’ seems, therefore, to result not from a great nuclear mass, but probably from a relatively small degree of condensation of chromatin.