First report of the cyanotoxins cylindrospermopsin and deoxycylindrospermopsin from Raphidiopsis curvata (Cyantobacteria)

A strain of Raphidiopsis (Cyanobacteria) isolated from a fish pond in Wuhan, P. R. China was examined for its taxonomy and production of the alkaloidal hepatotoxins cylindrospermopsin (CYN) and deoxy-cylindrospermopsin (deoxy-CYN). Strain HB1 was identified as R. curvata Fritsch et Rich based on morphological examination of the laboratory culture. HB1 produced mainly deoxy-CYN at a concentration of 1.3 mg(.)g(-1) (dry ut cells) by HPLC and HPLC-MS/MS. CYN was also detected in trace amounts (0.56 mug(.)g(-1)). A mouse bioassay did not show lethal toxicity when tested at doses up to 1500 mg dry weight cells(.)kg(-1) body weight within 96 h, demonstrating that production of primarily deoxy CYN does not lead to significant mouse toxicity by strain BB I. The presence of deoxy-CYN and CYN in R curvata suggests that Raphidiopsis belongs to the Nostocaceae, but this requires confirmation by molecular systematic studies. Production of these cyanotoxins by Raphidiopsis adds another genus, in addition to Cylindrospemopsis, Aphanizomenon, and Umezakia, now known to produce this group of hepatotoxic cyanotoxins. This is also the first report from China of a CYN and deoxy-CYN producing cyanobacterium.

Four new terrestrial species of Marionina (Clitellata, Enchytraeidae) from China and re-examination of M. hoVbaueri Moller

Enchytraeid surveys were made in China, mainly along the Changjiang (Yangtze) River Basin, during the period 1991-1999. Among the findings, four terrestrial species of Marionina are new to science and well illustrate the taxonomic complexity of the genus as currently defined. Marionina sinica sp. n. is characterized by a specific chaetal distribution, the marionine pattern of the dorsal blood vessel, and elongate, fusiform, spermathecal ectal ducts. Marionina sacculata sp. n. is distinguished by the possession of a pair of pouch-like oesophageal appendages in IV, the lack of lateral chaetae in VII-XI, a marionine pattern of the dorsal blood vessel, and short spermathecal ectal ducts gradually expanding into spherical ampullae. Both M. sinica and M. sacculata have minute bodies (2-3 mm long in vivo) and lack spermathecal accessory glands. The former species shows its closest aYnities with the European M. brendae Rota, 1995, whereas the latter is closest to the German M. hoVbaueri Moller, 1971, for which an amended diagnosis is provided. Marionina seminuda sp. n. has only ventral chaetal bundles, distributed from III onwards and bisetose. It is similar to the Holarctic M. subterranea (Knollner, 1935) in lacking entirely the lateral chaetae and in having the brain incised posteriorly, the dorsal vessel bifurcating behind the pharynx, and coelomocytes containing opaque granules, but diVers from it in having the longest chaetae in preclitellar segments and gland cells distributed all over the spermathecal ectal ducts. Marionina righiana sp. n. is diagnosed by the location of the head pore on the prostomium, the absence of lateral chaetae from VIII ( VII or IX) onwards, the possession of free spermathecae extending backwards through one to four segments, the brain deeply incised posteriorly, the lumbricilline pattern of the dorsal blood vessel, and the opacity of coelomocytes in vivo. Prior to this study, members of the genus so atypical as M. righiana with respect to the position of the head pore and the structure of the spermathecae were known only from South American soils. Until the taxonomy of Marionina has been more thoroughly assessed and revised, the assignment of the four species to this large assemblage should be regarded as tentative.

Phylogenetic relationships of the subclass Peritrichia (Oligohymenophorea, Ciliophora) with emphasis on the genus Epistylis, inferred from small subunit rRNA gene sequences

The peritrichs have been recognized as a higher taxon of ciliates since 1968. However, the phylogenetic relationships among them are still unsettled, and their placement within the class Oligohymenophorea has only been supported by the analysis of the small subunit rRNA gene sequence of Opisthonecta henneguyi. DNA was isolated directly from field-sampled species for PCR, and was used to resolve relationships within the genus Epistylis and to confirm the stability of the placement of peritrichs. Small subunit rRNA gene sequences of Epistylis plicatilis, Epistylis urceolata, Epistylis chysemydis, Epistylis hentscheli, Epistylis wenrichi, and Vorticella campanula were sequenced and analyzed using both distance-matrix and maximum-parsimony methods. In phylogenetic trees, the monophyly of both the genus Epistylis and the subclass Peritrichia was strongly supported, while V. campanula clustered with Vorticella microstoma. The topology in which E. plicatilis and E. hentscheli formed a strongly supported sister clade to E. urceolata, E. chrysemydis, and E. wenrichi was consistent with variations in the thickness of the peristomial lip. We concluded that the peristomial area, especially the. peristomial lip, might be the important phylogenetic character within the genus Epistylis.

Taxonomic re-evaluation of Aphanizomenon flos-aquae NH-5 based on morphology and 16S rRNA gene sequences

The taxonomy of Aphanizomenon flos-aquae strain NH-5, a producer of cyanotoxins, was re-evaluated by comparison with six other Aphanizomenon strains using morphological characteristics and 16S rRNA gene sequences. Strain NH-5 was concluded to be improperly identified as Aph. flos-aquae based upon (1) lack of bundle formation in the trichomes, (2) location of akinetes next to heterocytes, (3) lower similarities (less than 97.5%) in the 16S rRNA gene sequences relative to Aph. flos-aquae strains, and (4) comparison within a phylogenetic tree constructed from 16S rRNA gene sequences. The Aphanizomenon strains investigated in this study are classified to four morphological groups as described by the classical taxonomy of Komarek & Kovacik (1989). This classification was supported from the phylogenetic results of 16S rRNA gene sequences. This study also discusses the generic boundaries between Aphanizomenon and Anabaena.

Inland free-living nematodes in China: A historical review of taxonomic studies with descriptions of Aphanonchus orientalis sp nov (Chromadorida : Leptolaimidae) and Daptonema limnobia sp nov (Monhysterida : Xyalidae)

The study of inland free-living nematodes is relatively imperfect in China, only seventeen papers were previously published. Since the early researches in 20-30s, few works have been accomplished until 80s. Altogether 171 taxa were formerly recorded, among which, over eighty species have been re-combined. A checklist of the former records with notes on their distribution is presented in this paper. Recently, the function of free-living nematodes has received much attention from Chinese zoologists. Hence, the present authors carried out their studies with emphasis on taxonomy of inland nematodes. During the survey of freshwater lakes, two species are found to be nem to science. Aphanonchus orientalis sp. nov. is characterized by having sclerotized vagina, the presence of 10-11 tubular supplements and 42-62 alveoli supplements in males, but no alveoli in females. Daptonema limnobia sp, nov. is distinguished from other species of the genus in the presence of larger and more anteriorly located amphids, shorter bifurcated spicules, smaller apophysis of gubernaculum, shorter terminal setae, and postvulval uterine sac in females.

The freeliving nematode genus Parodontophora Timm 1963 (Nematoda : Axonolaimidae) is not exclusively marine: Parodontophora limnophila sp nov from freshwater in China

Parodontophora limnophila sp. nov. is described from Poyang Lake, the largest freshwater lake of China. It is characterized by having an amphid with its posterior end close to the base of the stoma, relatively short cephalic setae, opisthocephalic setae arranged as two subdorsal groups of three longitudinally arranged setae and two single subventral setae, excretory pore at the level of the anterior part of the stoma and renette gland 34-47% of the oesophageal length. To date, the new species is the only Parodontophora species found in freshwater habitats.

Two new species of Actinolaimidae thorne, 1939 (Nemata : Dorylaimida) from China

Two new species of Actinolaimidae are described from China. Trachactinolaimus brevicaudatus n. sp. is 3.4-4.4 mm long; a = 40-60, b = 3.5-5.2, c = 20-21 in female and 34-39 in male; odontostyle length is 29-33 mu m; spicules are 67-77 mu m long; and the stoma has four onchia with numerous mural denticles. The female has a longitudinal vulva, and the male has 20 to 23 contiguous ventromedian supplements. Egtitus sinensis n. sp. is 1.7-2.2 mm long; a = 24-33, b = 3.1-3.9, c = 16-19 in female and 0.7-0.9 in male; odontostyle length is 25-29 mu m; spicules are 55-56 mu m long; and the prerectum 53-77 pm long. The cardia is short and blunt conoid, 13-19 mu m long. The male has 12 to 13 ventromedian supplements at intervals of 2-3 mu m.

Notholca dongtingensis (Rotifera : Monogononta : Brachionidae), a new species from Dongting Lake, China

Notholca dongtingensis n.sp. was found in the second largest lake of China, Dongting Lake. It is related to Notholca labis Gosse, 1887 and N. kozhovi Vassilijewa & Kutikova, 1969. Its main distinguishing taxonomic features are a square-oval lorica, very short anterior spines, anterior lateral spines curving outwards and protrusile posterior margin of the ventral plate.

Rotifera recorded from China, 1893-1997, with remarks on their composition and distribution

A search of the literature on rotifers recorded from China, includes today 477 valid species names and 42 subspecies or infrasubspecific variants in 84 genera and 28 families recorded since 1893. Chinese rotifera research is reviewed, and all recorded species are listed with current taxonomic status and their first localities in China. Most of the named taxa are widely distributed or cosmopolitan, with only a small number (about 3%) possibly restricted to China. This fauna exhibits 15 endemic taxa. The composition and distribution of Chinese Rotifera are briefly analyzed. It is likely that considerably more rotifers remain to be described from China as further study to be carried on and taxonomic resolution improves.

Two new species of Rotifera from China

Two new rotifera species, Brachionus huangi n. sp, and Lecane chinesensis n. sp. are described and illustrated from different localities in China. The main distinguishing taxonomic features of B. huangi are three pairs of apical spines, a pair of symmetrical caudal spines and a wide caudal projection. For L. chinesensis, the main characteristics are the two-sided small extentions of the foot pseudosegment, the long and innercurved apical spines and ventral lorica anteriorly narrower than the dorsal one.

黄土高原(土娄)覆盖层与黏化层的土壤水文效应

黄土高原(土娄)土在《中国土壤系统分类(修订方案)》中属土垫旱耕人为土类的相应亚类,其土壤水分状况是诊断表层所属人为表层类堆垫表层(覆盖层)和诊断表下层(黏化层)的重要诊断特征。以土壤持水性能、蒸发性能和水分移动性能为切入点,对(土娄)土覆盖层和黏化层的土壤水文效应进行研究论证,以期对土垫旱耕人为土类及其亚类的诊断层与诊断特征获取更深层的认识。