Molecular characteristics of Camallanus spp. (Spirurida : Camallanidae) in fishes from China based on its rDNA sequences

In the,paper, we explored the intra- and interspecific evolutionary variation among species of Camallanus collected from different fish species in various regions of China. We determined the internal transcribed spacers of ribosomal DNA (ITS rDNA) sequences of these nematodes. The divergence (uncorrected p-distance) of ITS 1, ITS2, and ITS rDNA data sets confirmed 2 valid species of Camallanus in China, i.e., C. cotti and C. hypophthalmichthys. The 2 species were distinguished not only by their different morphologies and host ranges but also by a letranucleotide microsatellite (TTGC)n present in the ITS I region of C cotti. Phylogenetic analyses of the nematodes disclosed 2 main clades, corresponding to different individuals of C cotti and C. hypophthalmichthys from different fish species in various geographical locations, although the interior nodes of each clade received poor support.

Revision of the labeonine genus Sinocrossocheilus (Teleostei : Cyprinidae) from South China

Sinocrossocheilus was recently diagnosed by Su et al. (2003) as consisting of nine species, i.e. S. bamaensis, S. guizhouensis, S. liuchengensis, S. longibullus, S. tridentis, S. microstomatus, S. nigrovittatus, S. labiatus, and S. papillolabrus. It is actually a catch-all genus that is composed of some species misidentified from Pseudocrossocheilus and Hongshuia. Sinocrossocheilus is here redefined based mainly on the details of the lower lip morphology; it is easily separated from all other Asian Labeonini genera in possessing a lower lip with its median lobe modified into a densely papillated, greatly protruded, crescentic fold and a papillose, slightly protruded, triangular fleshy pad which is posteriorly continuous with the mental region. Two species are recognized in this genus: S. guizhouensis and S. labiatus. Detailed redescriptions are given for the two species. All remaining species do not fit with the new definition of Sinocrossocheilus; six species, i.e. S. papillolabrus, S. nigrovittatus, S. bamaensis, S. longibullus, S. liuchengensis, and S. tridentis, should be moved to Pseudocrossocheilus and S. microstomatus to Hongshuia.

Macrozoobenthic community of Fuxian Lake, the deepest lake of southwest China

Located in the Yunnan-Guizhou Plateau in southwest China, Fuxian Lake covers an area of 211 km(2), with maximum depth of 155 m. It is known to have a unique fauna, including 14 described endemic species. In order to describe the zoobenthic community of the lake more completely, the present study was conducted from August 2002 to August 2003. Altogether 62 benthic taxa, including 22 oligochaetes, 21 molluscs and 18 insects were identified, of which the dominant taxa belonged to Potamothrix, Procladius and Paraprososthenia. The standing stocks of benthos were much higher in the littoral (824 ind/m(2) in density, 3.72 g/m(2) in biomass) than in the profundal region (23 ind/m(2) in density, 0.10 g/m(2) in biomass). Species richness was greatest in summer and standing stocks were larger in spring and summer than in other seasons. Analyses of functional feeding groups indicated that collector-gatherers and scrapers were predominant in entire lake. Stepwise multiple regression analysis demonstrated that the water depth is the most important factor affecting the distribution of macrozoobenthos. (C) 2008 Elsevier GmbH. All rights reserved.

Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in surface sediment and bivalve from the Changjiang Estuary, China

Surface sediments and bivalves were collected from the Changjiang Estuary in December 2003 and November 2004, respectively. Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in these samples were measured with high-resolution chromatography (HRGC)/High Resolution Mass Spectrometer (HRMS). The concentrations of total PCDD/Fs and toxic equivalent (TEQ) were 169.83 +/- 119.63 and 0.81 +/- 0.36 pg/g dry weight (dw) in sediments, and 580.33 +/- 240.17 and 7.24 +/- 3.65 pg/g dw in bivalves. The homolog compositions of PCDD/Fs were similar among samples, the most abundant congener was octa-chlorinated dibenzo-p-dioxin (OCDD) and then octa-chlorinated dibenzofuran (OCDF) and 1,2,3,4,6,7,8-hepta-chlorinated dibenzo-p-dioxin (HOCDD). The herbicide pentachlorophenol (PCP) and sodium pentachlorophenol (Na-PCP) were proved the main source of PCDD/Fs in this area.

Preliminary hazard assessment of polychlorinated biphenyls, polybrominated diphenyl ethers, and polychlorinated dibenzo-p-dioxins and dibenzofurans to Yangtze finless porpoise in Dongting Lake, China

Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis), a protected endangered species, is the sole freshwater subspecies of finless porpoise, living only in the middle and lower reaches of the Yangtze River, China, and its appended lakes. Its population has decreased sharply to 1,400 because of human activities, including environmental contamination. In the present study, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were determined in the blubber, liver, kidney, stomach, small intestine, and brains of five individual Yangtze finless porpoises collected from 1998 to 2004. The results showed PCB concentrations ranged from 0.06 to 1.89 mu g/g lipid weight in the organs and consisted mainly of penta-, hexa-. and decachlorinated biphenyls. The PBDE concentrations were between 5.32 and 72.76 ng/g lipid weight. Tetra-, penta-, and hexabrominated diphenyl ethers were the major homologues. The PCDD/F concentrations ranged from 65 to 1,563 pg/g lipid weight, and their predominant homologues were penta- and hexachlorinated dibenzofurans and hepta- and octachlorinated dibenzo-p-dioxins. The hazard quotients (HQs) based on toxic equivalency were determined to be greater than one in all individuals for PCBs, for PCDD/Fs, and for PCBs and PCDD/Fs In addition, HQs would be higher if PBDEs were included. The results suggest that reduction of environmental contamination may contribute greatly to protecting this highly endangered species.

A new species of Allocreadium (Trematoda : Allocreadiidae) from freshwater fishes in the Danjiangkou Reservoir in China

A new species of Allocreadium, Allocreadium danjiangensis n. sp., is described from the intestine of several species of freshwater fish, including Abbottina rivularis (Basilewsky, 1855), Sarcocheilichthys nigripinnis nigripinns (Gunther, 1873), Gnathopogon argentatus (Sauvage et Dabry 1874), Opsariichthys uncirostris bidens (Gunther, 1873), and Erythroculter mongolicus mongolicus (Basilewsky, 1855) (Cyprinidae) from the Danjiangkou Reservoir in central China. The main morphological characters of the new species are as follows: vitelline follicles numerous, extending from the level of acetabulum to posterior extremity, distributed over both sides around the ceca; cirrus sac relatively large, developed, lying obliquely anterior to the acetabulum, extending from the level of the intestinal bifurcation to the central level of acetabulum, and overlapping left or right cecal; and ovary much smaller than testes, generally close to or even overlapping the anterior border of anterior testis. Observation by scanning electron microscopy shows only 2 kinds of tegumental formations, i.e., papillae and tubercles, instead of 3 types of tegumental formations, i.e., papillae, bosses, and minute sensor receptors observed on other species of the Allocreadiidae. The tegumental striations of the present species vary on the different parts of the body. In addition, a new structure, identified as the "groove" with a tonguelike tubercle, was observed on the inner wall of acetabulum.

Physiological advantages may contribute to successful invasion of the exotic Cyprinus carpio into the Xingyun Lake, China

Feeding and growth traits of Cyprinus carpio and Cyprinus pellegrini (both at age-0) were compared in three experiment, in an attempt to analyze potential causes for the displacement of the native C. pellegrini in the Xingyun Lake, Yuxi, Yunan, China. Experiment I was conducted in water which fluctuated between 15 and 20 degrees C. Experiment II and III were conducted in a laboratory and water temperature was maintained between 20 degrees C and 25 degrees C, respectively. Three common trends were noted for all three experiments: (1) feeding rate of C. carpio was lower than that of C. pellegrini, and this difference was found to be significant in experiment I; (2) growth rate of C. carpio was higher than C. pellegrini, and the difference was found to be significant in experiment II; (3) food conversion efficiency and energy retention efficiency for C. carpio were higher than those of C. pellegrini, and significant differences were noted in experiment I and II. Since the growth period for fish in the Xingyun Lake generally occurs when water temperatures are between 15 and 25 degrees C, it can be suggested that C. carpio has advantages over C. pellegrini in growth and food utilization efficiency, and lower food consumption than C. pellegrini. These physiological traits of C. carpio might allow this species to be more resistant to food shortage and predation, and may be partially responsible for the displacement of C. pellegrini by C. carpio.

Seasonal variations of estrogenic compounds and their estrogenicities in influent and effluent from a municipal sewage treatment plant in China

The seasonal variations of estrogenic compounds and the estrogenicities of influent and effluent were investigated by OF chemical analysis and in vitro assay in a municipal sewage treatment plant in Wuhan (China). The levels of eight estrogenic compounds, including 17 beta-estradiol (E-2) estrone (E-1), estriol (E-3) diethylstilbestrol (DES), 17 alpha-ethinylestradiol, nonylphenol (NP), 4-tert-octylphenol (OP), and bisphenol A (BPA), were measured by gas chromatography-mass spectrometry. Total estrogenic activity of sewage was quantitatively assessed using primary cultured hepatocytes of male Megalobrama amblycephala Yih using vitellogenin as a biomarker. The E-2 equivalents (EEQs) obtained from the chemical analysis were consistent with those measured by bioassay. The natural (E-1, E-2, and E-3) and synthetic (DES) estrogens, as well as NP, were the main contributors of the total EEQs of influent and effluent in the present study. The levels of natural estrogens E-1 and E-3 in the influent and effluent were higher in winter than in summer, whereas the situation for NP and OP was the reverse. The levels of E-2, DES, and BPA varied little among different seasons. 17 alpha-Ethinylestradiol was not detected in the influent and effluent. The estrogenicities of the influent and of the primary and secondary effluents were all higher in summer than in winter. Estrogenic activities in winter mainly originated from natural (E-1, E-2, and E-3) and synthetic (DES) estrogens, whereas the increase of EEQs in summer was contributed by NP The results from chemical analysis and bioassay demonstrate that estrogenic compounds cannot be entirely removed by the existing sewage treatment process, which should be further improved to protect aquatic ecosystems and human health.

Phosphorus in interstitial water induced by redox potential in sediment of Dianchi Lake, China

The sediment redox potential was raised in the laboratory to estimate reduction of internal available phosphorus loads, such as soluble reactive phosphorus (SRP) and total phosphorus (TP), as well as the main elements of sediment extracts in Dianchi Lake. Several strongly reducing substances in sediments, which mainly originated from anaerobic decomposition of primary producer residues, were responsible for the lower redox potential. In a range of -400 to 200 mV raising the redox potential of sediments decreased TP and SRP in interstitial water. Redox potentials exceeding 320 mV caused increases in TP, whereas SRP maintained a relatively constant minimum level. The concentrations of Al, Fe, Ca2+, Mg2+, K+, Na+ and S in interstitial water were also related to the redox potential of sediments, suggesting that the mechanism for redox potential to regulate the concentration of phosphorus in interstitial water was complex.

Perfluorinated compounds in the Pearl River and Yangtze River of China

A total of 14 perfluorinated compounds (PFCs) were quantified in river water samples collected from tributaries of the Pearl River (Guangzhou Province, south China) and the Yangtze River (central China). Among the PFCs analyzed, perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were the two compounds with the highest concentrations. PFOS concentrations ranged from 0.90 to 99 ng/1 and < 0.01-14 ng/1 in samples from the Pearl River and Yangtze River, respectively; whereas those for PFOA ranged from 0.85 to 13 ng/l and 2.0-260 ng/l. Lower concentrations were measured for perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS), perfluorooctanesulfoamide (PFOSA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorononaoic acid (PFNA), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUnDA). Concentrations of several perfluorocarboxylic acids, including perfluorododecanoic acid (PFDoDA), perfluorotetradecanoic acid (PFTeDA), perfluorohexadecanoic acid (PFHxDA) and perfluorooctadecanoic acid (PFOcDA) were lower than the limits of quantification in all the samples analyzed. The highest concentrations of most PFCs were observed in water samples from the Yangtze River near Shanghai, the major industrial and financial centre in China. In addition, sampling locations in the lower reaches of the Yangtze River with a reduced flow rate might serve as a final sink for contaminants from the upstream river runoffs. Generally, PFOS was the dominant PFC found in samples from the Pearl River, while PFOA was the predominant PFC in water from the Yangtze River. Specifically, a considerable amount of PFBS (22.9-26.1% of total PFC analyzed) was measured in water collected near Nanjing, which indicates the presence of potential sources of PFBS in this part of China. Completely different PFC composition profiles were observed for samples from the Pearl River and the Yangtze River. This indicates the presence of dissimilar sources in these two regions. (c) 2007 Elsevier Ltd. All rights reserved.

Characterization of complete genome sequence of the spring viremia of carp virus isolated from common carp (Cyprinus carpio) in China

The complete genome of spring viraemia of carp virus (SVCV) strain A-1 isolated from cultured common carp (Cyprinus carpio) in China was sequenced and characterized. Reverse transcription-polymerase chain reaction (RT-PCR) derived clones were constructed and the DNA was sequenced. It showed that the entire genome of SVCV A-1 consists of 11,100 nucleotide base pairs, the predicted size of the viral RNA of rhabdoviruses. However, the additional insertions in bp 4633-4676 and bp 4684-4724 of SVCV A-1 were different from the other two published SVCV complete genomes. Five open reading frames (ORFs) of SVCV A-1 were identified and further confirmed by RT-PCR and DNA sequencing of their respective RT-PCR products. The 5 structural proteins encoded by the viral RNA were ordered 3'-N-P-M-G-L-5'. This is the first report of a complete genome sequence of SVCV isolated from cultured carp in China. Phylogenetic analysis indicates that SVCV A-1 is closely related to the members of the genus Vesiculovirus, family Rhabdoviridae.

Effects of sand burial on biomass, chlorophyll fluorescence and extracellular polysaccharides of man-made cyanobacterial crusts under experimental conditions

Soil cyanobacterial crusts occur throughout the world, especially in the semiarid and arid regions. It always encounters sand burial, which is an important feature of mobile sand dunes. A greenhouse 41 study was conducted to determine the effects of sand burial on biomass, chlorophyll fluorescence and extracellular polysaccharides of man-made cyanobacterial crusts in six periods of time (0, 5, 10, 15, 20 and 30 d after burying) and at five depths (0, 0.2, 0.5, 1 and 2cm). The results indicated that with the increase of the burial time and burial depth extracellular polysaccharides content and Fv/Fm decreased correspondingly and there were no significant differences between 20 and 30 burial days under different burial depths. The degradation of chlorophyll a content appeared only at 20 and 30 burial days and there was also no significant difference between them under different burial depths. It was also observed a simultaneous decrease of the values of the Fv/Fm and the content of extracellular polysaccharides happened in the crusted cyanobacterium Microcoleus vaginatus Gom. It may suggest that there exists a relationship between extracellular polysaccharides and recovery of the activity of photosystem II (PS II) after rehydration.

In situ study on the control of toxic Microcystis blooms using phytoplanktivorous fish in the subtropical Lake Taihu of China: A large fish pen experiment

Three large fish pens (0.36 km(2) of each) stocked with silver and bighead carp were set up in Meiliang Bay for controlling toxic Microcystis blooms. The responses of plankton communities and food consumption of silver and bighead carp were studied. Crustacean zooplankton were significantly suppressed in the fish pens. Total phytoplankton biomass, Microcystis biomass and microcystin concentration were lower in the fish pens than in the surrounding lake water, but the difference was not statistically significant. The present stocking density of silver plus bighead carp (about 40 g/m(3) in July) was likely too low to achieve an adequate control of Microcystis. Silver carp fed mainly on phytoplankton but bighead carp mainly on zooplankton: mean zooplankton contribution in the gut was 31.5% for silver carp and 64.7% for bighead carp. Compared with previous studies, both carp species preyed upon more zooplankton because of the abundant food resource. Daily rations of silver and bighead carp were estimated by Egger's model in the main growing season. Filtration rate was calculated from the daily ration and the density of plankton in the lake. During May-October, filtration rates of silver and bighead carp for phytoplankton were 0.22-1.53 L g(-1) h(-1) and 0.02-0.68 L g(-1) h(-1), respectively, and filtration rates for zooplankton were 0.24-0.44 L g(-1) h(-1) and 0.08-1.41 L g(-1) h(-1), respectively. Silver carp had a stronger ability of eliminating phytoplankton than bighead carp. To achieve a successful bioniampulation with a minimum effect of ichthyoeutrophication, the stocking proportion of bighead carp should be controlled in the future practice. (c) 2007 Elsevier B.V All rights reserved.

Food composition and dietary overlap of macroinvertebrates in a shallow eutrophic lake in China: spatial and temporal variations

The present study was conducted in Lake Donghu, a suburban eutrophic lake arising from the middle reaches of the Yangtze River, China. Food composition of 32 taxa of zoobenthos was analyzed from 1251 gut samples. Macroinvertebrate primary consumers ingested mainly detritus, sand grains and diatoms. The predators primarily preyed on rotifers, crustaceans, oligochaetes and chironomid larvae. The dietary overlap was relatively high among collector taxa but low among other macroinvertebrates. Food composition and dietary overlap of macroinvertebrates changed considerably, both spatially and temporally. Food web structure differed between inshore and offshore regions of Lake Donghu. The inshore web was relatively complex and dynamic whereas the offshore web was simple and stable. Taxon-specific changes of diet seem to have little effect on the benthic food web structure in offshore waters of a eutrophic lake.

Benthic algae of the Gangqu River, Shangrila, China

We surveyed the benthic algae at 32 sites in the Gangqu River system during May 2005. Among the 162 different taxa observed, 88.8% were diatoms. Achnanthes linearis and Achnanthes lanceolata var. elliptica were the dominant species, comprising 17.1% and 14.3% of the total relative abundance, respectively.