Graphene-oxide modified polyvinyl-alcohol as microbial carrier to improve high salt wastewater treatment

This work discussed the preparation and characterization of graphene oxide (GO) modified polyvinyl alcohol (PVA) for bacteria immobilization to enhance the biodegrdation efficiency of saline organic wastewater. GO-PVA material has lamellar structure with higher surface area to support bacterial growth and high salinity tolerance. It significantly stimulated the bacterial population by 1.4 times from 2.07×103 CFU/mL to 5.04×103 CFU/mL, and the microbial structure was also improved for salinity tolerance. Acinetobacter, Pseudomonas and Thermophilic hydrogen bacilli were enriched inside GO-PVA materials for glucose biodegradation. Compared to the CODCr removal efficiency with only PVA as the carrier (52.8%), GO-PVA material had better degradation performance (62.8%). It is proved as a good candidate for bioaugmentation to improve biodegradation efficiency in hypersaline organic wastewater

KARYOLOGICAL STUDIES OF THE HYBRID LARVAE OF HALIOTIS DISVERSICOLOR SUPERTEXTA FEMALE AND HALIOTIS DISCUS DISCUS MALE

To determine the genomic composition of the interspecific hybrid between Haliotis diversicolor supertexta female and H. discus discus male at an early developmental stage, veliger larvae produced from hybrid (SJ-5 and SJ-50) and pure species crosses (SS and JJ) were sampled and analyzed using standard karyological methods and genomic in situ hybridization. In hybrid metaphase spreads, chromosomes from both parents were detected, except one metaphase, which showed the H. diversicolor supertexta haploid karyotype. The genomic composition of the hybrid was also confirmed through preliminary genomic in situ hybridization results. Many more aneuploids and chromosome fragments were found in the hybrids than those in the control pure species crosses, indicating genome instability and chromosome loss in the hybrids. In the hybrid hypodiploid metaphase spreads, two intact sets of H. diversicolor supertexta chromosomes and several H. discus discus chromosomes were detected by pairing. Spontaneous diploidization of the maternal chromosome set was shown to occur in hybrid larvae, as 2.2% heterogeneous triploid and 17.9% hypodiploids with two intact H. diversicolor supertexta chromosome sets for SJ-5. The current findings suggest that uniparental chromosome elimination along with spontaneous diploidization of maternal chromosome sets may be the reason for allogynogenesis production in H. diversicolor supertexta X H. discus discus hybridization

ALLOGYOGENETIC PROGENY ARE PRODUCED FROM A HYBRID ABALONE CROSS OF FEMALE HALIOTIS DIVERSICOLOR AND MALE HALIOTIS DISCUS DISCUS

Interspecific hybrid families of female Haliotis diversicolor X male H. discus discus were produced and analyzed using amplified fragment length polymorphism (AFLP) technology to reveal the genetic makeup of F1 progenies. The survival rates of the hybrid F1 were very low, ranging from 0-0.13%. Twenty hybrid F1 from 3 families along with 3 different female parents and their common male parent were analyzed with 3 AFLP primer combinations. In total, 266 markers were detected. Genetic relationships among the progenies and the parents were evaluated by generating a similarity and genetic distance matrix. The genetic divergence between Haliotis diversicolor and Haliotis discus was at a high level, with genetic distance ranging from 1.471-1.492. The AFLP band patterns of hybrid F1 progeny were similar to those of the female parents, but were quite different from that of the male parent. The mean genetic distance between hybrid F1 and their female parents were 0.024-0.039, slightly less than that among the female parents, which indicates that the hybrid F1 shared high genetic similarity with their female parents, Haliotis diversicolor. However, 0-0.8% of total AFLP bands of each individual were found to be parental bands, and 0-3.3% were found to be nonparental bands. The possible reason for the presence of paternal-specific and nonparental bands is discussed

The effects of nickel on the reproductive ability of three different marine copepods

Lethal and sublethal toxicity of Nickel (Ni) to three marine copepods Tigriopus japonicus, Apocyclops borneoensis and Acartia pacifica was investigated. The 48-h LC50 values were 17.70, 13.05 and 2.36 mg l(-1) Ni, respectively. A. pacifica was found to be the most sensitive to Ni in acute exposure tests. In order to assess sublethal effects of Ni on copepod reproduction, the test organisms were exposed to four nominal Ni concentrations 0, 10, 100, 1000 mu g l(-1) Ni. The results indicated that offspring production of T. japonicus and A. borneoensis was significantly reduced after exposure to 10 mu g l(-1) Ni. Whereas egg production and egg hatching success of A. pacifica were significantly reduced at 100 and 10 mu g l(-1) Ni, respectively. Exposure of copepods to the highest Ni concentration caused a severely reduced nauplii production from T. japonicus, A. borneoensis and A. pacifica by 87.8, 56.9 and 65.8%, respectively, and a significantly reduced egg production of A. pacifica by 74.4%. These results show that Ni excess in the coastal environment can have detrimental effects on reproduction of copepods.National Natural Science Foundation of China [40876060

Spatial heterogeneity of a microbial community in Kongsfjorden, Svalbard during late summer 2006 and its relationship to biotic and abiotic factors

The 16S and 18S ribosomal ribonucleic acid genes of microbial organisms collected from the contrasting environments (temperature, salinity, silicate, phosphate and nitrate, p <0.05) of the inner and outer basins of Kongsfjorden (Spitsbergen, Arctic) were studied using polymerase chain reaction-denaturing gradient gel electrophoresis(DGGE) fingerprinting. Comparison of the microbial fingerprints and the physicochemical parameters revealed that molecular methodology exhibited a greater sensitivity. Sequences obtained from bacterial DGGE were affiliated with four main phylogenetic groups of bacteria: Proteobacteria(Alpha, Beta and Gamma), Bacteroidetes, Verrucomicrobia and Cyanobacteria. The relationships between the genotype distribution of these microbes and associated biotic/abiotic factors, revealed by canonical correspondence analysis, showed that Station 1 at 30 m (outer fjord) was grouped separately from the other sites. This difference could be a consequence of the thermocline and base of the euphotic layer at this depth where the Atlantic and Arctic-type waters overlapped

Resisting flow-laboratory study of rheotaxis of the estuarine copepod Pseudodiaptomus annandalei

【英文文摘】Rheotaxis is a ubiquitous phenomenon among aquatic animals and thought to be an adaptation to maintain populations in flowing waters. While many estuarine copepods can retain their populations in estuaries with net seaward flow, rheotaxis of individual copepods has not been reported before. In this study, the behavior of a calanoid copepod Pseudodiaptomus annandalei in flow was examined in a recirculating laboratory flume. This estuarine copepod displayed different responses to ambient flow fields while swimming in the water column or attaching to the flume bed (walls). Copepods in the water column showed vigorous countercurrent swimming by occasional bounding when flow velocity was increased up to 2.1 cm s 1, but none of the individuals in the water column were retained in the flume when flow speeds were higher than 4 cms 1. This indicates P. annandalei profits little from rheotaxis to withstand flow when they were swimming in the water column. Instead, more individuals attempted sinking downwards to the slow flow region near the flume bed (walls) and showed active substrate attachment to avoid being flushed out by the high-velocity channel flow. The results suggest that P. annandalei benefits from rheotaxis and association with the substrate which allows them to hold position well at ambient flow velocities up to 3 cms 1. These adaptive responses might be important for population maintenance

Sodium current of neurosecretory cells in the eyestalk from the shrimp Penaeus japonicus

The properties of the inward current of medulla terminalis-X-organ (MTXO) cells isolated from the Penaeus japonicus eyestalk were studied with the whole-cell clamp technique in the presence of Ca2+ and K+ channel blockers. The inward currents had a threshold at about -50 mV and peaked at -10 mV. The reversed potential (V-rev) was very close to V-Na, the theoretical Nernst equilibrium potential for Na+. V-rev followed V-Na when the external Na+ concentration was varied and the currents were entirely suppressed by 30 nM tetrodotoxin (TTX), indicating that it was carried by Na+. The smooth line of concentration-dependent inhibition of sodium currents by TTX represented the best. t with the Hill equation, yielding an IC50 of 2.1 +/- 0.1 nM. The values of the half-maximal activation voltage V-h were -20.6 +/- 0.5 and -19.3 +/- 0.5 mV, respectively, in the absence and presence of 2 nM TTX. TTX had no significant effect on the voltage dependence of steady-state activation and inactivation of I-Na. Taken together, the results suggest that the inward current recorded under our experimental conditions was carried by sodium ions. owing through fast voltage-dependent Na+ channels. (C) 2009 National Natural Science Foundation of China and Chinese Academy of Sciences. Published by Elsevier Limited and Science in China Press. All rights reserved.National Natural Science Foundation of China [30300269]; Technical Innovation Project of Fujian [2003J018

Seasonal variations of ATPase activity and antioxidant defenses in gills of the mud crab Scylla serrata (Crustacea, Decapoda)

【英文摘要】The mud crab Scylla serrata is an important commercial crustacean being widely distributed along the southeastern coast of China. This crab and particularly its gills are subjected to seasonal fluctuations of environmental factors due to direct exposure to seawater. The investigation of seasonal variations of ATPase and antioxidant defenses in gills could be helpful for the understanding of physiological regulation mechanism of seasonal adaptations. In this study, mud crabs were collected from the subtropical waters near Xiamen island, Southeast China (24°26′46′′N, 118°04′04′′E), in August and November, 2002, and February and May, 2003, respectively, being considered as specimens from summer, autumn, winter and spring, respectively. Only healthy intermoult male crabs without carapace or appendage damage were used, having a carapace width of 7.05 ± 0.52 cm and a wet weight of 130 ± 20 g. The activities of four ATPases and three antioxidation enzymes (superoxide dismutase, catalase, glutathione peroxidase) and the content of malondialdehyde in gills were measured. The results showed that the activities of Na+, K+-ATPase, Mg2+-ATPase, Ca2+-ATPase and Ca2+, Mg2+-ATPase reached maximum levels similarly in summer and decreased in winter. The activities of superoxide dismutase and catalase were higher in summer and lower in winter, with a significant decrease in winter compared to the other seasons (p < 0.01). Glutathione peroxidase activity was higher in summer, and lower in autumn, being significantly higher in summer or winter than in spring or autumn (p < 0.01). Malondialdehyde content was higher in summer and lower in spring with significant differences among the different seasons (p < 0.01). In summary, the obvious seasonal activity variations of four ATPases and antioxidant enzymes and the content of malondialdehyde reflect a seasonal regulation of the physiological metabolising enzyme and the antioxidant capacity to cope with seasonal alterations of environment factors such as fluctuating salinities and temperatures. Communicated by K. Yin