Effects of dietary manganese on growth and tissue manganese concentrations of juvenile gibel carp, Carassius auratus gibelio

A 68-day growth trial was conducted in a flow-through system to determine the effect of dietary manganese levels on growth and tissue manganese concentration of juvenile gibel carp (Carassius auratus gibelio). Seven purified diets containing 7.21, 8.46, 9.50, 10.50, 13.03, 19.72 and 22.17 mg manganese (as manganic sulfate) per kilogram diet were fed to triplicate groups of fish (initial weight 3.21 +/- 0.01 g). The results showed that dietary manganese levels did not significantly affect feed intake of the fish. Specific growth rate, feed efficiency, total hepatic superoxide dismutase activity, carcass and skeletal manganese concentration increased significantly with increased dietary manganese(P < 0.05) while condition factor decreased significantly(P < 0.05). It was concluded that dietary requirement of manganese was 13.77 mg Mn per kilogram diet. Carcass and skeletal manganese concentration could also be used to evaluate the manganese requirement. Total hepatic superoxide dismulase activity was not a sensitive indicator for dietary requirement.

Bioinformatic identification of genes encoding C1q-domain-containing proteins in zebrafish

C1q is the first subcomponent of classical pathway in the complement system and a major link between innate and acquired immunities. The globular (gC1q) domain similar with C1q was also found in many non-complement C1q-domain-containing (C1qDC) proteins which have similar crystal structure to that of the multifunctional tumor necrosis factor (TNF) ligand family, and also have diverse functions. In this study, we identified a total of 52 independent gene sequences encoding C1q-domain-containing proteins through comprehensive searches of zebrafish genome, cDNA and EST databases. In comparison to 31 orthologous genes in human and different numbers in other species, a significant selective pressure was suggested during vertebrate evolution. Domain organization of C1q-domain-containing (C1qDC) proteins mainly includes a leading signal peptide, a collagen-like region of variable length, and a C-terminal C1q domain. There are 11 highly conserved residues within the C1q domain, among which 2 are invariant within the zebrafish gene set. A more extensive database searches also revealed homologous C1qDC proteins in other vertebrates, invertebrates and even bacterium, but no homologous sequences for encoding C1qDC proteins were found in many species that have a more recent evolutionary history with zebrafish. Therefore, further studies on C1q-domain-containing genes among different species will help us understand evolutionary mechanism of innate and acquired immunities.

Zebraflsh z-otu, a novel Otu and Tudor domain-containing gene, is expressed in early stages of oogenesis and embryogenesis

Several studies have suggested that Otu domain had de-ubiquitinating activity and Tudor domain was important for the formation of germ cells. Here, we reported a novel zebrafish ovary-specific gene containing Otu and Tudor domain, z-otu, which was expressed at stages I-III oocytes and embryonic stages from zygotes to early blastula during embryonic cells maintained their totipotency. Therefore, z-otu might link the ubiquitin signaling pathway to early oogenesis and maintaining the totipotency of embryonic cell. (c) 2005 Elsevier B.V. All rights reserved.

Characterization of two genes encoding leucine-rich repeat-containing proteins in grass carp Ctenopharyngodon idellus

The cDNAs and genes of two different types of leucine- rich repeat-containing proteins from grass carp ( Ctenopharyngodon idellus) were cloned. Homology search revealed that the two genes, designated as GC-GARP and GC-LRG, have 37% and 32% deduced aminoacid sequence similarities with human glycoprotein A repetitions predominant precursor ( GARP) and leucine-rich alpha2-glycoprotein (LRG), respectively. The cDNAs of GC-GARP and GC-LRG encoded 664 and 339 amino acid residues, respectively. GC-GARP and GC-LRG contain many distinct structural and/or functional motifs of the leucine- rich repeat (LRR) subfamily, such as multiple conserved 11-residue segments with the consensus sequence LxxLxLxxN/CxL ( x can be any amino acid). The genes GC-GARP and GC-LRG consist of two exons, with 4,782 bp and 2,119 bp in total length, respectively. The first exon of each gene contains a small 5'-untranslated region and partial open reading frame. The putative promoter region of GC-GARP was found to contain transcription factor binding sites for GATA-1, IRF4, Oct-1, IRF-7, IRF-1, AP1, GATA-box and NFAT, and the promoter region of GC-LRG for MYC-MAX, MEIS1, ISRE, IK3, HOXA9 and C/EBP alpha. Phylogenetic analysis showed that GC-GARP and mammalian GARPs were clustered into one branch, while GC-LRG and mammalian LRGs were in another branch. The GC-GARP gene was only detected in head kidney, and GC-LRG in the liver, spleen and heart in the copepod ( Sinergasilus major)- infected grass carp, indicating the induction of gene expression by the parasite infection. The results obtained in the present study provide insight into the structure of fish LRR genes, and further study should be carried out to understand the importance of LRR proteins in host - pathogen interactions.

Water solubility enhancement of phthalates by cetyltrimethylammonium bromide and beta-cyclodextrin

Water solubility enhancements of six phthalates (five aliphatic phthalates and one phenyl phthalate) by cetyltrimethylammonium bromide (CTAB) and beta-cyclodextrin (beta-CD) were studied at 25 degreesC. The solubilities of these plithalates are remarkably enhanced by CTAB solutions above the critical micelle concentration (cmc). Only marginal enhancement of phthalate solubility was observed in solutions containing CTAB below its cmc and beta-CD at low concentrations (less than 5 mM). The solubility enhancements of the plithalates are proportional to the added amount of CTAB and beta-CD. Partition coefficients of the plithalates between monomeric CTAB surfactant and water (K-MN) and between CTAB micelle and water K-MC) were estimated from the experimental data. The mechanisms of solubility enhancements by CTAB and beta-CD were discussed. A log-linear equation was proposed and evaluated for the solubilization by CTAB below cmc, while the previously proposed linear partitioning model was questioned. The structures of the complexes formed between plithalates and beta-CD were proposed, and the formation constants were estimated. The values of log K-MC, log K-MN, and log Kbeta-CD of the plithalates were found to correlate linearly with the log K-OW of plithalates, with the exception of the solid phenyl phthalate.

Cytological and biochemical alterations in Carassius auratus hepatocytes from exposure to sediment containing dioxins and related compounds

Cytological and biochemical alterations of crucial carp (Carassius auratus) hepatocytes were characterized after exposure to sediments from a lake contaminated with dioxins and other industrial chemicals. Carp were exposed in 20 L water containing 25, 50, or 100 g of contaminated sediment for 2 and 4 weeks. Ultrastructural changes in the liver were characterized by severe enlargement of hepatocytes. Alterations in the cell. included formation of condensed and irregular cell nucleus, polynuclei, dispersed heterochromatin, enlargement of the nucleolus, and degeneration of the nucleus. Mitochondrial numbers were reduced and cristae were deformed. Myelin figures and lysosomes were increased, and sometimes cell organelles and cell matrix were totally lost after 4 weeks of exposure. The ultrastructural alterations were correlated with exposure time and sediment concentrations. Hepatosometic index was significantly increased in experimental groups at 2 and 4 weeks as compared with the control group. EROD enzyme activities were strongly induced in liver. A trend from rough endoplasmic reticulum (RER) to SER was observed. Our results suggest that the dioxin-like compounds bound by sediment were bioavailable to C. auratus and cause sublethal effects.

(Ga,Mn)As 和闪锌矿结构CrSb 的分子束外延生长制备和磁性质研究

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

注Mn InAs/GaAs 量子点光电磁性质的研究

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

稀磁半导体(Ga, Mn)As磁光性质的研究

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

Si 共掺杂和高温退火对(Ga,Mn)As 结构和磁性质的影响

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

稀磁半导体(Ga,Mn)As和铁磁金属-半导体异质结Fe/GaAs铁磁相变过程的研究

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

稀磁半导体（Ga,Mn)As 的超快磁光谱研究

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稀磁半导体(Ga,Mn)As 中自旋动力学的探索与研究

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