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.

Resting metabolism and heat increment of feeding in mandarin fish (Siniperca chuatsi) and Chinese snakehead (Channa argus)

Resting metabolism was measured in immature mandarin fish Siniperca chuatsi weighing 42.1-510.2 g and Chinese snakehead Channa argus weighing 41.5-510.3 g at 10, 15, 20, 25, 30 and 35 degreesC. Heat increment of feeding was measured in mandarin fish weighing 202.0 (+/-14.0) g and snakehead weighing 200.8 (+/-19.3) g fed swamp leach Misgurnus anguillicaudatus at 1% body weight per day at 28 degreesC. In both species, weight exponent in the power relationship between resting metabolism and body weight was not affected by temperature. The relationship between resting metabolism and temperature could be described by a power function. The temperature exponent was 1.39 in mandarin fish and 2.10 in snakehead (P < 0.05), indicating that resting metabolism in snakehead increased with temperature at a faster rate than in mandarin fish. Multiple regression models were used to describe the effects of body weight (W, g) and temperature (T, C) on the resting metabolism (R-s, mg O-2/h): In R-s = - 5.343 + 0.772 In W + 1.387 In T for the mandarin fish and In R-s = -7.863 + 0.801 ln W + 2.104 In T for the Chinese snakehead. The proportion of food energy channelled to heat increment was 8.7% in mandarin fish and 6.8% in snakehead. (C) 2000 Elsevier Science Inc. All rights reserved.

Effects of Bothriocephalus acheilognathi on the polarization response of pronephric leucocytes of carp, Cyprinus carpio

An in vitro assay was used to examine the effect of Bothriocephalus acheilognathi Yamaguti, 1934 (Cestoda: Pseudophyllidea) on the polarization response of pronephric leucocytes of carp, Cyprinus carpio. Leucocytes, isolated from naive, naturally-infected fish and carp injected intraperitoneally with cestode extracts, were exposed to parasite extracts (protein concentrations 0-10.0 mu g ml(-1)), for up to 24 h in the presence or absence of carp serum. In general, polarization responses of the pronephric leucocytes, primarily neutrophils and eosinophils, increased with incubation time although there was no significant difference in the response induced by the different protein concentrations. Differences in the polarization response were, however, observed in naive, naturally infected and injected fish and the cells responded differently in the presence and absence of carp serum. In the absence of carp serum the polarization response of pronephric leucocytes in vitro was significantly reduced with cells obtained from injected and naturally infected fish compared with those obtained from naive carp. This suppression of leucocyte migration was however reduced by the addition of carp serum to the in vitro system. The role of this interaction between the possible suppression of polarization induced by the parasite and stimulation by serum is discussed.

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.

Phylogeny of the Amphiliidae (Teleostei : Siluriformes)

The freshwater African catfish family Amphiliidae had been reviewed based on the 73 osteological characters with Diplomystidae, dagger Hypsidoridae, Amblycipitidae, Sisoridae, and Bagridae as out-groups. Because the family position of Leptoglanis (Bagridae/Amphiliidae) is under debate, this genus has been taken as an out-group too. Results of the study indicate that: 1) the Amphiliidae is not a monophyletic group and must now be restricted to the genera Amphilius and Paramphilius; the two subfamilies Amphiliinae and Doumeinae are separated by the sisorids Euchiloglanis (with most of the glyptosternid fishes) and Glyptothorax (with most of the non-glyptosternid fishes); 2) no synapomorphies were found for the subfamily Amphiliinae. 3) The five genera of subfamily Doumeinae constitute a monophyletic group, Andersonia being the sister-group of the four other genera; subfamily Doumeinae + Leptoglanis form the family Doumeidae. The glyptosternids no longer belong to the Sisoridae (family restricted to the non-glyptosternids) and represent the new family Glyptosternidae. (C) 1999 Editions scientifiques et medicales Elsevier SAS.

GENOTOXIC EFFECTS OF LINEAR ALKYL BENZENE SULFONATE, SODIUM PENTACHLOROPHENATE AND DICHROMATE ON TETRAHYMENA-PYRIFORMIS

DNA in macro- and micronuclei of Tetrahymena pyriformis treated with linear alkyl benzene sulfonate (LAS) and sodium pentachlorophenate (PCP-Na) were determined by microspectrophotometry. The effects on rate of formation of macronuclear DNA extrusion bodies were also studied. We found DNA content of micronuclei in 0.14 ppm LAS and 0.9 ppb PCP-Na was lower than in that of the control, and LAS was able to increase the formation rate of macronuclear DNA extrusion bodies (the formation rate was 54% in 11.3 ppm LAS and 25.6% in 16.7 ppm dichromate). We concluded that 0.14 ppm LAS (below the maximum acceptable toxicant concentration) was genotoxic, whereas 0.014 ppm LAS was not. Dichromate 0.05 ppm and 0.9 ppb PCP-Na, equal to and below the maximum acceptable toxicant concentration, respectively, were potentially genetoxic.