Cytological studies on six cyprinid fishes

The chromosome complements of six cyprinid fishes were studied, using the routine air-drying Giemsa staining technique. The diploid chromosome number recorded is 2n = 50 (8m+18sm+14st+10t) with NF = 90 in Aspidoparia morar, 2n = 50 (8m+12sm+12st+18t) with NF = 82 in Crossocheilus latius latius, 2n = 50 (6m+12sm–16st+16t) with NF = 90 in Labeo pangusia, 2n = 70 (16m+6sm+16st–32t) with NF = 108 in Perilampus atpar, 2n = 48 (4m+6st+38t) with NF = 58 in Puntius chrysopterus and 2n = 50 (2m+2sm+4st+42t) with NF = 58 in P. tetrarupagus. Sex chromosomes are not identifiable in any of these species. A pair of marker chromosomes has been observed in all species excepting A. morar.     

Comparative karyology of species of the genera <Emphasis Type="Italic">Misgurnus</Emphasis> and <Emphasis Type="Italic">Cobitis</Emphasis> (Cobitidae) from the Amur River Basin in connection with their taxonomic relations and the evolution of karyotypes

Data are first provided on karyotypes of four species of Cobitidae from the Amur Basin: Misgurnus nikolskyi (2n = 50 = 10m + 4 sm + 36sta, NF = 64), Cobitis lutheri, (2n = 50 = 12m + 8sm + 30sta, NF = 70), C. choii (2n = 50 = 8m + 10sm + 8st + 24a, NF = 68), and C. melanoleuca (2n = 50 = 6m + 16sm + 28sta, NF = 72), and number of chromosomes in M. mohoity (2n = 50) and karyotypes of C. melanoleuca from the basin of the Don, Malyi and Bol’shoi Uzen rivers, and Selenga. These data are discussed in connection with problems of taxonomy of the studied genera, as well as the evolutionary relations of their karyotypes. On the basis of karyological differences between the populations of C. melanoleuca from different parts of the range, a new subspecies C. melanoleuca gladkovi subsp. nov. that inhabits waters of Europe is described.     

云南三种角蟾的细胞遗传学研究

本文研究了云南三种角蟾的核型,C－带和Ag-NORs,结果显示宽头大角蟾,其2n=26(16M 8SM 2T),NF=50,5 8,No.10为T,次缢痕和Ag－NORs位于1p per,该区域同时还呈现C－带正染,其全部染色体的着丝点都有强弱不等的C－带染色;大花角蟾的核型2n=26(16M 8SM=2ST),NF＝50,5＋8,No.6为ST,次缢痕和Ag-NORs位于5q pes,全部着丝点均有C－带正染;凹顶角蟾5n=26(16M 4SM 6T),NF=46,6 7.No.11-13为T,次缢痕和Ag-NORs位于5q per,全部着丝点及周围均有浓C－带正染。三个种均未发现与性别相关的异形染色体,最后讨论了角蟾属核型演化的途径。     

Comparative morphology and ecomorphology of the gut in European cyprinids (Telostei)

The patterns of coiling of the gut were compared in 22 species of Eurasian Cyprinidae. In selected species, also the length of gut and mucosal surface structure were compared. Piscivorous ( Aspius aspius ), planktivorous ( Abramis ballerus ) fishes as well as species feeding mainly on plankton and wind-borne' drift'( Alburnus alhurnus, Pelecus cultratus ) have the relatively shortest guts, with only a single loop. The same simple arrangement of a short gut is present in many euryphagous species with more or less carnivorous tendencies ( Abramis sapa, Alburnoides bipunctalus, Abramis brama, Blicca bjoerkna, Chalcalburnus chalcoides memo, Gobio gobio, Leuciscus cephalus, Leuciscus leuciscus, Rutilus rutilus, Scardinius erythrophthalmus. Tinea tinea, Vimba vimba ). Some benthivorous winnowers (oropharyngeal sorters) and species with herbivorous feeding tendencies have relatively long guts showing a more complex pattern of loops and coils ( Barbus barbus, Carassius carassius, Chondrostoma nasus, Ctenopharyngodon idella, Cyprinus carpio ). The goldfish, Carassius auratus , has the most complex coils. Scanning electron microscopy of the mucosal surface revealed five types of folding in the intestinal bulb which were only loosely related to feeding: 1, smooth surface ( Aspius aspius, Leuciscus cephalus, Vimba vimba ); 2, irregularly branching folds ( Alhurnus alburnus, Barbus barbus, Blicca bjoerkna, Chalcalburnus chalcoides memo, Leuciscus leuciscus, Rutilus rutilus, Scardinius erythrophthalmus ); 3, curl-like folds ( Tinea tinea ); 4, net-like folding pattern ( Abramis brama ); 5, honeycomb-like mucosal structure ( Cyprinus carpio ).     

Further survey of chromosomal polymorphisms in the freshwater planarian Polycelis auriculata

Although the chromosomal number of Polycelis (Seidlia) auriculata Ijima et Kaburaki is basically 2n = 6, this species shows remarkable chromosomal polymorphisms in different populations. Among worms collected at 30 stations in the central part of Japan's Main Island and in Hokkaido, we found five new karyotypes, considered to be variations of tetraploidy and diploidy: 4n?fis¹. + 1 = 3SM + 2A + 3T₁ + 2T₂ + 4M = 14, 4n?fis².(B) = 2SM + 2A + 4T₁ + 2T₂ + 4M + (0?2B) = 14 –16, 4n?fis². + 1 = 2SM + 2A + 4T₁ + 2T₂+5M= 15, 4n?fis².?2 = 2SM + 2A + 4T₁ + 4M = 12, and 2nM- = 2SM + 2A = 4 (where SM = submetacentric; A = acrocentric; T₁ and T₂ = telocentric; M = metacentric; B = B-chromosome; fis¹. and fis². = occurrence of one or two centric fissions, respectively; and M- = deletion of a metacentric chromosome). These karyotypes exist singly in one individual or as various mixoploids within the same individual. No individual having only karyotype 2nM- has yet been found. This brings the total number of known karyotypes in P. auriculata to 17; these can be arranged in an order that we believe reflects their evolution.     

Karyotypes and geographical distribution of ricefishes from Yunnan,southwestern China

Morphometric and karyotypic studies were made on two species of ricefishes collected from Yunnan, southwestern China.Oryzias latipes from Yunnan had the same morphological and karyological characteristics asO. latipes collected from eastern China. The Yunnan populations had 2n, 46 chromosomes consisting of 3 metacentric, 8 submetacentric, 2 subtelocentric, and 10 acrocentric pairs, the arm number (NF) being 68 (2n=46, NF=68, 3M+8SM+2ST+10A). The karyotype was characterized by having a “large” metacentric pair and nucleolus organizer regions (NORs) on the short arms of a submetacentric pair.Oryzias minutilius from Yunnan had the same morphological characteristics asO. minuiillus from Thailand and Burma, although the karyotype was different from that collected from Thailand. The Yunnan population had 2n, 42 chromosomes consisting of 21 acrocentric pairs, NF being 42 (2n=42, NF=42, 21A). The karyotype was characterized by having NORs at the telomeric regions of an acrocentric pair.Oryzias latipes occurs widely on the eastern Yunnan Plateau where the climate is temperate or subtropical, whereasO. minutilius is found in Xishiangbanna, the southern low mountain areas of Yunnan, where the climate is tropical.     

云南三种同域分布的棘蛙（蛙科Ranidae：无尾目Anura）的核型和银带研究

本文比较分析了云南景东地区三种同域分布棘蛙的核型和Ａｇ－ＮＯＲｓ。花棘蛙２ｎ＝２６（１６Ｍ＋ １０ＳＭ）,ＮＦ＝５２,次缢痕和Ａｇ－ＮＯＲｓ位于１ｐｉｎｔｅｒ,Ｎｏｓ．２－４,８,９等为ＳＭ。棘肛蛙２ｎ＝４０（１６Ｍ＋ ２０ＳＭ＋２ＳＴ＋２Ｔ）,ＮＦ＝７８,Ｎｏｓ．５－９,１１－１３,１５,１７等１０对为ＳＭ,Ｎｏ．３为ＳＴ,Ｎｏ．１８为Ｔ,其余 均为Ｍ,Ａｇ－ＮＯＲｓ位于１１Ｐ。二种的Ａｇ－ＮＯＲｓ都有异形现象。双团棘胸蛙２ｎ＝６４Ｔ,次缢痕和Ａｇ－ ＮＯＲＳ在４ｑｐｅｒ。都未发现异形性染色体。最后,对棘蛙属的核型演化机制和物种形成方式作了讨论。     

Chromosomes of three freshwater stingrays (Rajiformes Potamotrygonidae) from the Rio Negro basin, Amazon, Brazil

Potamotrygonidae is the representative family of South American freshwater elasmobranchs. It is a monophyletic group containing 20 species grouped into three genera. Three species belonging to two genera of this family were collected from the middle Negro River, Amazonas, Brazil, and studied cytogenetically: Paratrygon aiereba, Potamotrygon motoro and Potamotrygon orbignyi. Paratrygon aiereba presented 2n = 90 chromosomes and 4M+2SM+10ST+74A. Both species of Potamotrygon presented 2n = 66 chromosomes and differed in their chromosomal formulas: P. motoro had 18M+12SM+10ST+26A and P. orbignyi had 22M+10SM+8ST+26A. No sex heteromorphism was detected. The Fundamental Number (FN) was 106 for the three species. A system of multiple NORs was found in the three species, but with interspecific differences in terms of location and position of the active Ag-NORs sites. Paratrygon aiereba presented only four sites on the short arms of two chromosomal pairs, both in terminal regions. Potamotrygon motoro presented seven sites, on the long and short arms, all in terminal regions of non-homologous chromosomes; P. orbignyi presented eight sites on the long arms, all in terminal regions, of non-homologous chromosomes. The constitutive heterochromatin was in pericentromeric regions of all chromosomes, and no significant interspecific difference was found in relation to this marker.     

洞庭湖水系沅水和澧水野鲫的染色体组型及资源保护

鲫(Carassius auratus)是洞庭湖水系一种重要的经济鱼类。为了解洞庭湖水系野鲫的细胞遗传背景,采用PHA和秋水仙素活体注射法,对沅水和澧水采集的野鲫样本逐一进行肾细胞染色体制片及组型分析。结果发现,在两条河流的野鲫群体中均检测出染色体数为100和基本染色体数为150的两种不同倍性个体,其中,两条河流染色体数为100的二倍体鲫组型公式为2N=28M+22SM+28ST+22T,NF=150;基本染色体数为150的三倍体鲫组型公式为3N=42M+33SM+42ST+33T,NF=225。在沅水和澧水不同采样点随机采集的共100尾野鲫中,检测出的三倍体比例(85%)远高于二倍体(15%),且二倍体与三倍体鲫个体在形态特征上不存在明显差异(P0.05)。两种不同倍性鲫在同一水体的共存对于鲫的遗传进化与选育具有一定的理论和实践意义,而二倍体鲫种群的大量减少,则提示我们应该从染色体组遗传多样性角度加强对洞庭湖水系二倍体野鲫资源的保护。     

Juvenile fishes in macrophyte beds: influence of food resources, habitat structure and body size

Mean juvenile fish abundance and fish frequency in a large lowland river during low discharge largely differed among the unvegetated and three morphologically contrasted macrophyte habitats. Single separate models revealed that juvenile fish distribution was largely influenced by trophic variables. With the exception of Leuciscus cephalus , which responded mainly to physical variables (depth and substratum), multiple regression models emphasized the importance of trophic variables for fish distribution. For Blicca bjoerkna , L. cephalus and Lepomis gibbosus , habitat shifts with respect to prey size were apparent; small juvenile fishes mainly responded to small zooplankton abundance, whereas large individuals were more influenced by the abundance of large zooplankton. Whatever the species, predictions from multiple regression models were always better for large individuals. Small juvenile fishes appeared to be less affected by the habitat variables measured, and exhibited more uniform spatial distribution. The relative importance of trophic resources and habitat physical structure among macrophyte types for fish-habitat relationships is discussed, and the necessity of quantifying habitat structural complexity is emphasized.     

赤链华游蛇的染色体组型与银带带型研究

该文研究赤链华游蛇的染色体组型与NOR     

Length–weight and length–length relationships for nine fish species from Lhasa River Basin,Tibet, China

The present study reports length–weight relationships (LWR) and length–length relationships (LLR) for five native freshwater fish species (Schizopygopsis younghusbandi, Triplophysa orientalis, T. tibetana, T. stewartii and T. stenura) and four introduced freshwater fish species (Pseudorasbora parva, Carassius auratus, Micropercops cinctus and Oryzias latipes) captured in the Lhasa River Basin, Tibet, China. Five of the LWRs are presented for the first time.     

Muscle water control in crustaceans and fishes as a function of habitat, osmoregulatory capacity, and degree of euryhalinity

This study aimed at detecting possible patterns in the relationship between Anisosmotic Extracellular Regulation (AER) and Isosmotic Intracellular Regulation (IIR) in crustaceans and teleost fish from different habitats and evolutionary histories in fresh water (FW), thus different osmoregulatory capabilities, and degrees of euryhalinity. Crustaceans used were the hololimnetic FW Aegla schmitti, and Macrobrachium potiuna, the diadromous FW Macrobrachium acanthurus, the estuarine Palaemon pandaliformis and the marine Hepatus pudibundus; fishes used were the FW Corydoras ehrhardti, Mimagoniates microlepis, and Geophagus brasiliensis, and the marine-estuarine Diapterus auratus. The capacity for IIR was assessed in vitro following wet weight changes of isolated muscle slices incubated in anisosmotic saline (~ 50% change). M. potiuna was the crustacean with the highest capacity for IIR; the euryhaline perciforms G. brasiliensis and D. auratus displayed total capacity for IIR. It is proposed that a high capacity for IIR is required for invading a new habitat, but that it is later lost after a long time of evolution in a stable habitat, such as in the FW anomuran crab A. schmitti, and the Ostariophysian fishes C. ehrhardti and M. microlepis. More recent FW invaders such as the palaemonid shrimps (M. potiuna and M. acanthurus) and the cichlid G. brasiliensis are euryhaline and still display a high capacity for IIR.     

中国西南地区6种植物的核型研究及其系统学意义

采用植物细胞学研究方法对主要采自中国西南地区横断山的6种植物:扁核木(Prinsepia utilis)、小叶金露梅(Potentilla parvifolia)、峨眉繁缕(Stellaria omeiensis)、金铁锁(Psammosilene tunicoides)、山卷耳(Cerastium pusillum)和独尾草(Eremurus chinensis)进行染色体数目和核型研究。研究表明:(1)6个种的核型公式和不对称性如下:扁核木2n=2x=30=1M+20m+9sm,2A;小叶金露梅2n=2x=28=21m+7sm,2B;峨眉繁缕2n=8x=72=1M+71m,1B;金铁锁在同居群下有倍性变化,2n=2x=14=14m,1A和2n=4x=28=28m,1A;山卷耳2n=2x=24=24m(2sat),1A;独尾草2n=2x=14=2m+2sm+8st+2t,4B。(2)讨论了染色体资料在这些物种分类和系统上的意义,支持扁核木为李亚科下的扁核木属;位于委陵菜属木本系的小叶金露梅主要以二倍体和四倍体为主,而草本系的委陵菜属植物多为多倍体。(3)该研究首次报道峨眉繁缕为八倍体,是繁缕属发现的最高倍性的物种;对比金铁锁属与蝇子草属的染色体研究发现,金铁锁属可能是由它们的共同祖先通过非整倍化产生;该研究首次发现山卷耳存在染色体数目2n=24的情况,且有1对随体;独尾草的研究进一步证明该物种可能为二型核。     

Trichodinid Protozoa (Ciliophora: Peritrichida) from Freshwater Fishes of Rybinsk Reservoir,USSR1

During the spring of 1981, trichodinid protozoa were collected from the gills or urinary bladder of the following species of fishes of Rybinsk Reservoir, USSR, located on the upper reaches of the Volga River system: Esox lucius, Rutilus rutilus, Leuciscus idus, Blicca bjoerkna, Abramis ballerus, Pelecus cultratus, Lota lota, and Perca fluviatilis. A total of 13 species of Trichodinidae was recovered from Rybinsk fishes, among which are three new species of the genus Trichodina: T. izyumovae n. sp. from the gills of L. idus, T. borokensis n. sp. from the gills of P. cultratus, and T. kupermani n. sp. from the gills of A. ballerus. Other species of trichodinids reported are T. modesta Lom, 1980; T. nigra Lom, 1969; T. pediculus (O. F. Müller, 1786); T. prowazeki Grupcheva & Lom, 1980; T. rostrata Kulemina, 1968; T. urinaria Dogiel, 1940; T. ophiocephalus Kostenko & Karaev, 1976; Paratrichodina incisa (Lom, 1959); Trichodinella epizootica (Raabe, 1950); and Tripartiella copiosa Lom, 1959. Photomicrographs and morphometric data are presented for each species and aspects of their host and geographic distribution discussed. Trichodina algonquinensis Li & Desser, 1983 is considered a synonym of T. urinaria Dogiel, 1940.     

Ecosystem engineering by larvae of net-spinning stream caddisflies creates a habitat on the upper surface of stones for mayfly nymphs with a low resistance to flows

1. Field and laboratory experiments were conducted to examine the effect of larval retreats of the net‐spinning stream caddisfly Hydropsyche orientalis on abundances on flow exposed stone surfaces of nymphs of the mayfly Ephemerella setigera, which prefer slow flow conditions, and to determine whether the construction of retreats ameliorated the habitat and made it more suitable for E. setigera. 2. In a field experiment, artificial substrates with retreats of H. orientalis had higher E. setigera abundances than substrates lacking retreats. In addition, abundances of E. setigera nymphs increased significantly with those of H. orientalis larvae on the upper surface of boulders in streams. 3. The drift loss of E. setigera from plates, with and without retreats, was investigated along a current velocity gradient in a laboratory channel experiment. Nearly all E. setigera nymphs remained on the plates with retreats, even at the highest current velocity. In contrast, on the plates without retreats, the drift loss of E. setigera nymphs increased as the current velocity increased. 4. These results suggested that the habitat amelioration by H. orientalis retreats provided a refuge location for E. setigera nymphs and increased their abundances on stone surfaces exposed to flow forces.     

Identification and physical characterization of yeast glucoamylase structural genes

Summary Each one of at least three unlinked STA loci (STA1, STA2 and STA3), in the genome of Saccharomyces diastaticus controls starch hydrolysis by coding for an extracellular glucoamylase. Cloned STA2 sequences were used as hybridization probes to investigate the physical structure of the family of STA genes in the genomes of different Saccharomyces strains. Sta⁺ strains, each carrying a single genetically defined STA locus, were crossed with a Sta^– strain and the segregation behavior of the functional locus (i.e. Sta⁺) and sequences homologous to a cloned STA2 glucoamylase structural gene at that locus were analyzed. The results indicate that in all strains examined there is a multiplicity of sequences that are homologous to STA2 DNA but that only the functional STA loci contain extensive 5 and 3 homology to each other and can be identified as residing on unique fragments of DNA; that all laboratory yeast strains examined contain extensive regions of the glucoamylase gene sequences at or closely linked to the STA1 chromosomal position; that the STA1 locus contains two distinct glucoamylase gene sequences that are closely linked to each other; and that all laboratory strains examined also contain another ubiquitous sequence that is not allelic to STA1 and is nonfunctional (Sta^–), but has retained extensive sequence homology to the 5 end of the cloned STA2 gene. It was also determined that the DEX genes (which control dextrin hydrolysis in S. diastaticus), MAL5 (a gene once thought to control maltose metabolism in yeast) and the STA genes are allelic to each other in the following manner: STA1 and DEX2, STA1 and MAL5, and STA2 and DEX1 and STA3 and DEX3.     

Biogeographic patterns in the chromosomal distribution of a satellite DNA in the banded tetra Astyanax fasciatus (Teleostei: Characiformes)

The As-51 satellite DNA is a transposon-like sequence formerly described for arthropods and physically identifiable by fluorescent in situ hybridization. In the present work, we describe the occurrence of this sequence, as well the C-banding and karyotype composition, in populations of the group Astyanax fasciatus from Mogi-Guaçu (Araras-SP), Paranapanema (Angatuba and Pilar do Sul-SP), Ribeira de Iguape (Sete Barras-SP) and Tietê (Indaiatuba and Salesópolis-SP) river basins. The specimens from Sete Barras (10 M + 20SM + 12ST + 6A) and Araras (8 M + 22SM + 12ST + 6A) have 2n?=?48 chromosomes. The samples from Angatuba, Pilar do Sul and Indaiatuba presented 2n?=?46 chromosomes (12 M + 20SM + 10ST + 4A). The individuals collected in Salesópolis showed three cytotypes, bearing 2n?=?46 (12 M + 20SM + 10ST + 4A), 2n?=?48 (8 M + 22SM + 12ST + 6A) and 2n?=?50 (8 M + 16SM + 14ST + 12A). C-banding revealed large heterochromatic blocks at terminal chromosomal regions in all populations and/or cytotypes. All analyzed populations have conspicuous blocks carrying the As-51 satellite DNA, although the number of chromosomes bearing this repetitive sequence was variable among them. Such differences were not related to the diploid number of individuals, but rather to a biogeographic pattern. Aspects of the karyotype evolution and distribution of this sequence in distinct populations are discussed.     

Polyploidy and new chromosome counts in Anaphalis (Asteraceae: Gnaphalieae) from the Qinghai‐Tibet Plateau of China

Abstract Anaphalis is one of the largest genera of the Asian Gnaphalieae (Asteraceae) and is most diversified on the Qinghai‐Tibet Plateau. The chromosome numbers and karyomorphology of six species from seven populations were investigated for the first time for this region. Chromosome numbers have been newly documented for four species: Anaphalis deserti (2n = 56 = 24 median [m]+ 24 submedian [sm]+ 8 acrocentric [st]); Anaphalis plicata (2n = 56 = 26m + 30sm); Anaphalis xylorhiza (2n = 28 = 2 median point [M]+ 14m + 12sm); and Anaphalis rhododactyla (2n = 56 = 32m + 24sm). Two further counts are in agreement with the previously reported numbers, that is, Anaphalis royleana (2n = 28 = 4M + 6m + 18sm) and Anaphalis margaritacea (2n = 28 = 12m + 16sm). A new polyploid cytotype (2n = 56 = 26m + 30sm) was found in the Zougong population of A. margaritacea. Polyploidy is for the first time reported for Anaphalis, with four out of seven counts being tetraploid. Our cytological results suggest that polyploids might have played an important role in the evolution of Anaphalis on the Qinghai‐Tibet Plateau.     

棕色田鼠的细胞遗传学研究

本次首次报告棕色田鼠（Microtus mandarinus)的核型,核型公式为2n=50=2(M,T) 2SM 44T XX(M,SM),XY(SM,ST),发现第一对常染色体及X性染色体存在多态现象,在所研究的15只雌性个体中有7只雌性个体的细胞只有1条X性染色体,性染色体组成为XO型,核型公式为2n=49=2(M,ST) 2SM 44T＋XO,。其中X性染色体不同于雄性中的X（SM）,为M类型,本文提出的综色田鼠3种核型与Brown等人（1964）提出的Microtus oregoni的3种核型（XO,YO,XY）有异,本文还阐述了染色体多态产生的机制和探讨了XO型个体发生的机理及其繁殖。