Morphometric Variation in the Hypotrich Ciliate Genus Euplotes*†

SYNOPSIS. A quantitative method for the analysis of cirral patterns in the genus Euplotes is developed and contrasted with alternative approaches. Inherent variations in cirral pattern, as they are reflected in frequency distributions of intercirral distances, are ascertained through subclonal analyses of Euplotes harpa samples grown under different conditions. This assessment of the extent of variation within a form having 10 frontoventral cirri provides a basis for a comparative study of other Euplotes of cirrotype 10. These results suggest that all marine cirrotype 10 forms with a single dargyrome have the same configuration of frontoventral and transverse cirri. Similarly, most marine double dargyrome forms of cirrotype 10 have this same cirral pattern, and thus constitute variations upon the same morphometric theme.     

Dorsal Kinetosomal Distributions in the Ciliate Genus Euplotes1

The percentage allocations of ciliary units to each ciliary row across the dorsal surface were assessed for seven marine and five freshwater populations, representing the most commonly collected morphotypes of the genus Euplotes. In marine forms, there is a spectrum of dorsal kinetosomal distributions, within which is included the characteristic distribution for the vannus complex of sibling species. In contrast, there are only two basic ciliary patterns on the dorsal surface of the most ubiquitous freshwater “species”. The congruence between the classification of morphotypes based on dorsal ciliary patterns and that based on ventral cirral patterns is remarkable, despite the morphogenetic independence of kinetosomal structures on these two surfaces.     

Quantitative Analyses of Interbreeding in Populations of vannus-Morphotype Euplotes, with Special Attention to the Nominal Species E. vannus and E. crassus

ABSTRACT. Classical genetic techniques were applied to clonal cultures of the Euplotes vannus-crassus-minuta sibling species complex in an effort to provide some resolution to the species problem among these hypotrichs. Complex mating interactions were observed among clonal stock cultures derived from samples collected from sympatric and allopatric populations in a wide geographic survey. These results suggested that the classical model for the mating type inheritance and determination in these Euplotes is necessary but not sufficient to describe the mating mating interactions among populations of these ciliates. Successful conjugation between the nominal species E. crassus and E. vannus was observed routinely, and crosses between these two nominal species did not differ significantly from those among the other clonal stock cultures with respect to mating intensity and exconjugant survival. Data from backcrosses suggests that E. vannus and E. crassus can and do exchange genes. Based upon these data, we conclude that E. vannus and E. crassus comprise a single, highly polymorphic species with countless small populations, among which incomplete genetic exchange takes place.     

A Comparison of Three Populations of the Ciliate Genus, Paracichlidotherus Grim 1992. New Fish Hosts, and Biogeography; Revised Genus Description

ABSTRACT Two populations of Paracichlidotherus (Ciliophora. Nyctotheridae) were collected from the intestines of the Surgeon-fishes, Zebrasoma flavescens. and Acanthurus nigricans , from waters around the island of Guam. They were examined after Protargol staining and compared with the type population for 14 morphological characters. Right and left posterior short kinetal rows of very close kinetosomes and apparently fused cilia are described based on light microscopy and scanning electron microscopy. They often appear to be part of a second posterior suture system on each side. From transmission electron microscopic studies, kinetid structures of somatic dikinetids are described and compared for normal and fused cilia. They are similar, but in the latter, a fibril connects adjacent dikinetids. The buccal overture is V shaped at its posterior aspect. The genus is described more fully based on these characteristics.     

Morphological Drift Accompanying Nascent Population Differentiation in the Ciliate Euplotes vannus

A rare phenomenon can occur in ciliated protists of the genus Euplotes, which can undergo genetic recombination by the normal outbreeding process of conjugation following mild starvation. Occasionally, the dominant mutation for the autogamy trait arises. Individuals possessing the trait show obligate self-fertilization upon mild starvation. This yields, after normal asexual division, a population of individuals that are reproductively isolated from the parental outbreeding strain. A morphometric analysis of sympatric autogamous and non-autogamous populations of Euplotes vannus from Somalia demonstrates that there has been morphological drift in gross body proportions in the autogamous populations. However, the positional patterns of the locomotory organelles on the ventral surface remain unchanged. The changes in body proportions in the autogamous populations are relevant to the mechanics of the conjugation process, which involves fusion of the oral regions of paired cells belonging to complementary mating types.     

中国兔属动物的分类现状和分布

兔属 (Lepus)动物是一类广泛分布、彼此差异较小的哺乳动物 ,属于兔形目 (Lagomorpha)、兔科(Leporidae)。本文根据目前的分类现状 ,列出中国兔属种、亚种名录和分布区 ;对中国兔属动物的研究历史进行了综述 ;并针对蒙古兔、华南兔、云南兔、中亚兔和东北黑兔分类地位存在的争议进行了讨论     

A Branched-chain Amino Acid Aminotransferase from the Rumen Ciliate Genus Entodinium

A branched-chain amino acid aminotransferase was extracted from rumen ciliates of the genus Entodinium and was partially purified by Sephadex G-200, DEAE-cellulose and DEAE-Sephadex A-50 column chromatography. The purified enzyme was active only with leucine, isoleucine and valine, and required pyridoxal phosphate as cofactor. The amino acids competed with each other as substrates. The enzyme had optimal activity at pH 6.0 in phosphate buffer. The K_m values for the substrates and cofactor are as follows: 1.66 for leucine; 0.90 for isoleucine; 0.79 for valine; 0.29 mM for α-ketoglutarate: and 0.1 μM for pyridoxal phosphate. Enzyme activity was inhibited by p-chloromercuribenzoate and HgCl₂. Gel filtration indicated the enzyme to have a molecular weight of 34,000.     

木霉属真菌的系统学及其应用研究

介绍了木霉属真菌的分类系统 ,有关木霉种系发育的分子生物学研究进展 ,以及在酶制剂、农业和环境保护中的应用概况。     

Differential DNA Amplification and Copy Number Control in the Hypotrichous Ciliate Euplotes crassus

ABSTRACT. During macronuclear development in hypotrichous ciliated protozoans, several thousand macronuclear DNA molecules are amplified several-hundred fold. We investigated the regulation of this amplification by determining the copy numbers of three different macronuclear DNA molecules in the hypotrichous ciliate Euplotes crassus. Two of the macronuclear DNA molecules were present in approximately 1,000 copies per cell, while the third was present in approximately 6,500 copies per cell. These reiteration levels were achieved either during macronuclear development, or shortly thereafter, and were maintained during vegetative growth. The most abundant macronuclear DNA molecule is present as a single-copy sequence in the micronuclear genome. Thus, its high copy number results from differential amplification. These results indicate that DNA amplification during macronuclear development is regulated individually for each macronuclear DNA molecule.     

A Morphometric Study of Populations of the Centaurea jacea Complex (Asteraceae) in Belgium

Abstract: The Centaurea jacea aggregate is a polymorphic polyploid complex whose taxonomic treatment is still controversial. A numerical taxonomic approach was applied to 394 individuals of known ploidy level, from 19 populations, based on the main diagnostic characters proposed in earlier revisions. Populations from xeric grasslands were not considered. Principal Component Analysis shows that variation within the complex is continuous. UPGMA Cluster Analysis based on population means supports the recognition of three groups of populations. However, the limits between these groups are blurred to a considerable extent due to extensive within-population polymorphism. It is argued that the Belgian populations of Centaurea jacea occurring in mesic grasslands should be treated as a single species, with three subspecies. The two extremes of the morphological gradient can be referred to as C. jacea subsp. jacea and C. jacea subsp. nigra, with C. jacea subsp. pratensis occupying an intermediate position. Most populations from Belgium are tetraploid, a diploid chromosome number being found only in populations of C. jacea subsp. nigra from the Ardennes massif. On average, diploids grow at higher altitude and on more acidic soils than tetraploids. Finally, a key to the three subspecies is provided.     

Conjugation-Specific Genes in the Ciliate Euplotes crassus: Gene Expression from the Old Macronucleus

ABSTRACT. Following mating or conjugation, the hypotrichous ciliate Euplotes crassus undergoes a massive genome reorganization process. While the nature of the rearrangement events has been well studied, little is known concerning proteins that carry out such processes. As a means of identifying such proteins, differential screening of a developmental cDNA library, as well as construction of a cDNA subtraction library, was used to isolate genes expressed only during sexual reproduction. Five different conjugation-specific genes have been identified that are maximally expressed early in conjugation, during the period of micronuclear meiosis, which is just prior to macronuclear development and the DNA rearrangement process. All five genes are retained in the mature macronucleus. Micronuclear, macronuclear, and cDNA clones of one gene ( conZ47 ) have been sequenced, and the results indicate that the gene encodes a putative DNA binding protein. In addition, the presence of an internal eliminated sequence in the micronuclear copy of the conZ47 gene indicates that this conjugation-specific gene is transcribed from the old macronucleus.     

The Excystment Process in the Ciliate Euplotes muscicola: An Integrated Light and Scanning Electron Microscopic Study1

Resting cysts and the excystment process in the freshwater ciliate Euplotes muscicola were studied by both light and scanning electron microscopy. Groups of distinctly crested resting cysts adhere to the substrate. Silver-stained preparations reveal surface conservation of dorsal kinetosomes and dorsal argyrome while ventral organelles are directed inward. Excystment involves the development of an expanding excystment vacuole concurrent with a localized thinning on the dorsal cyst wall surface. Cells exit through the pre-formed ostiole, mid-dorsal region first, initially by the force of cytoplasmic streaming, but later aided by cirral movement. Newly emerged cells retain the excystment vacuole and show no dorsal ridging. As the cell expels its excystment vacuole and partially unfolds, normal trophont morphology is re-established. Both cyst structure and cyst typology have implications for hypotrich taxonomy.     

Mating Types, Breeding System, Conjuàtion and Nuclear Phenomena in the Marine Ciliate Euplotes cristatus Kahl from the Gulf of Naples

SYNOPSIS. The marine ciliate Euplotes cristatus Kahl (Ciliophora, Hypotrichida), collected off Capri, Gulf of Naples, is described in detail. From populations, 6 different mating types, representing 1 variety or syngen, have been isolated. The breeding relations revealed a multiple mating type system characteristic of other members of the Hypotrichida that have been investigated. Presumably a 7th mating type was found which does not mate with any of the others. Although this may belong to another syngen, it could represent a mating type which has not yet reached sexual maturity or 1 which may be in a period of decline. Animals of different mating type do not mate immediately after being mixed but usually 3 or more hours later. An agglutination reaction involving many specimens is absent. Instead, 2 ciliates engage in a “pairing play” before joining firmly in conjugation. Well-fed or actively feeding and dividing ciliates do not mate; mating occurs only after the food becomes gradually depleted or when the food supply is sharply cut off. All mating types appear to be extremely stable. Neither selfing pairs (intraclonal conjugation) nor autogamy have been observed within any clonal culture during the several years under investigation. Cell-free filtrates from 1 mating type do not elicit mating or induce conjugation with specimens of a different mating type. The general pattern of nuclear events in conjugation and exconjugant reorganization is as follows: 1 preliminary division, 3 pregamic (prezygotic) divisions, fertilization, and generally 1 or occasionally 2 postzygotic divisions. The fate of micronuclear products may be determined by their size and location. Those which are larger and close to the cell membranes of the joined conjugants persist and/or divide. Those which are smaller are carried by cyclosis toward the center of each ciliate and degenerate. The degenerating macronucleus of each conjugant becomes segmented in a more or less uniform manner resulting in 4 subspherical masses. Two become localized in the anterior end of a conjugant and 2 in the posterior end. Those in the posterior end are always the first to degenerate completely and disappear. In nuclear reorganization of the exconjugant, fusion of the macronuclear anlage with parts of the old macronucleus does not occur.     

韩国黄蚜小蜂属分类研究(膜翅目:蚜小蜂科)

本文报道采自韩国的黄蚜小蜂属5种,包括1新种（Aphytis albus,sp．nov．)及4个韩国新记录种(Adiaspidis,A.japonicus,Aproclia和Avandenboschi),编制了雌成虫检索表。新种模式标本保存在韩国国立树木园和东北林业大学昆虫标本室。     

云南猛蚁属四新种记述（膜翅目：蚁科）

记述云南高黎贡山自然保护区猛蚁属 4新种。至此已在中国记载猛蚁属昆虫 12种 :中华猛蚁 P. sinensis Wheeler,阿里山猛蚁 P. alisana Terayama,知本猛蚁 P. chipo-nensis Terayama,五齿猛蚁 Ponera pentodontos Xu,勐腊猛蚁 Ponera menglana Xu,南贡山猛蚁 Ponera nangongshana Xu,龙林猛蚁 Ponera longlina Xu,巴卡猛蚁 Ponera ba-ka Xu,黄色猛蚁 Ponera xantha,sp. nov.,坝湾猛蚁 Ponera bawana,sp. nov.,二齿猛蚁 Ponera diodonta,sp. nov.、片马猛蚁 Ponera pianmana,sp. nov.。编制了中国猛蚁属 12种工蚁分种检索表并附插图。模式标本保存于西南林学院资源学院昆虫标本室。新种示差鉴别特征及模式标本情况如下 :1.黄色猛蚁 Ponera xantha,新种 (图 13～ 15 )本新种近似巴卡猛蚁 P. baka Xu (图 10～ 12 ) ,但背面观腹柄结近三角形 ,长宽相等 ;侧面观腹柄下突后下缘无齿。正模 :工蚁 ,No.A97- 2 70 ,云南省腾冲县界头乡大营 ,2 0 0 0 m,1999- V- 0 2 ,付磊采于中山湿性常绿阔叶林内2.坝湾猛蚁 Ponera bawana,新种 (图 19～ 2 1)本新种近似日本猛蚁 P. japonica Wheeler(图 37～ 39) ,但头部正面观头侧缘较直 ,后头角较突出 ;并胸腹节背面长于斜面 ;腹柄下突后下缘仅具 1微小的齿 ,窗孔小而圆。正模     

A New Species of the Genus Tor from Yunnan, China (Teleostei: Cyprinidae)

A new species of the subfamily Barbinae, Tor yingjiangensis, is recognized from Yunnan province, China. It can be distinguished from other Tor species by the following combination of characters: last simple dorsal-fin ray osseous and non-serrated; no forward directed predorsal procumbent spine; head length considerably longer than body depth; no tubercles on the snout or sides of the face; 18–20 gill rakers on the outside of first gill arch; 24–26 lateral line scales; median lobe of lower lip short, its posterior margin truncate, not extending to the vertical across the inner corners of the mouth; and the condition of the lower lip consistent in individuals of different sizes. The new species has been misidentified previously as Tor putitora (Hamilton, F. 1822. An account of the fishes found in the River Ganges and its Branches. Edinburgh & London. 405 pp), which occurs in the Ganges and Indus River basins. The new species can easily be distinguished from T. putitora by having 3–3.5 (vs. 2.5) scales from lateral line to pelvic-fin origin, shorter caudal peduncle length (13.0% vs. 17.2% of standard length), lesser body depth (26.4% vs. 24.0% of standard length) and longer caudal peduncle depth (12.0% vs. 10.9% of standard length), no longitudinal stripe present along side of body, and eyes visible in ventral view of head.