[Bioremediation of chlorothalonil-contaminated soil by utilizing Pseudomonas sp. strain CTN-3].

Chlorothalonil is the priority organic pollutant listed by the U.S. Environmental Protection Agency. To utilize the function of microbial degradation in the bioremediation of chlorothalonil-contaminated soil is of practical significance. In this study, a chlorothalonil-degrading Pseudomonas sp. strain CTN-3 isolated from pesticide-contaminated soil was used to examine the chlorothalonil-degrading capacity of the strain and related affecting factors in a microcosm. In sterilized soil, the effect of CTN-3 on chlorothalonil degradation was better than that in unsterilized soil. Various factors, including soil pH, temperature, initial chlorothalonil concentration, and inoculum size, affected the degradation of chlorothalonil by the strain. With the inoculum size of 10(6) CFU x g(-1) soil, the CTN-3 at 15-30 degrees C and pH 5.8-8.3 could effectively degrade 10-200 mg x kg(-1) of chlorothalonil, suggesting that the strain CTN-3 had great potential in the bioremediation of chlorothalonil-contaminated soil.

Lysobacter ruishenii sp. nov., a chlorothalonil-degrading bacterium isolated from a long-term chlorothalonil-contaminated soil.

An aerobic, Gram-negative bacterial strain, designated CTN-1(T), capable of degrading chlorothalonil was isolated from a long-term chlorothalonil-contaminated soil in China, and was subjected to a polyphasic taxonomic investigation. Strain CTN-1(T) grew at 15-37 °C (optimum 28-30 °C) and at pH 6.0-9.0 (optimum pH 7.0-7.5). The G+C content of the total DNA was 67.1 mol%. Based on 16S rRNA gene sequence analysis, strain CTN-1(T) was related most closely to Lysobacter daejeonensis DSM 17634(T) (97.1  % similarity), L. soli DCY21(T) (95.7  %), L. concretionis Ko07(T) (95.5  %), L. gummosus LMG 8763(T) (95.3 %) and L. niastensis DSM 18481(T) (95.2  %). The novel strain showed less than 95.0 % 16S rRNA gene sequence similarity to the type strains of other Lysobacter species. The major cellular fatty acids of strain CNT-1(T) were iso-C16:0 (23.0  %), iso-C15:0 (21.4  %) and iso-C17:1ω9c (15.3  %). The major isoprenoid quinone was Q-8 (99 %), and the major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. These chemotaxonomic data supported the affiliation of strain CTN-1(T) to the genus Lysobacter. Levels of DNA-DNA relatedness between strain CTN-1(T) and L. daejeonensis DSM 17634(T) were 34.6-36.1  %. Phylogenetic analysis based on 16S rRNA gene sequences, DNA-DNA hybridization data and biochemical and physiological characteristics strongly supported the genotypic and phenotypic differentiation of strain CTN-1(T) from recognized species of the genus Lysobacter. Strain CTN-1(T) is therefore considered to represent a novel species of the genus Lysobacter, for which the name Lysobacter ruishenii sp. nov. is proposed. The type strain is CTN-1(T) (=DSM 22393(T) =CGMCC 1.10136(T)).

[Effect of the chelator BPCBG on the decorporation of uranium in vivo and uranium-induced damage of human renal tubular epithelial cells in vitro].

This study is to assess the efficacy of BPCBG on the decorporation of uranium (VI) and protecting human renal proximal tubular epithelial cells (HK-2) against uranium-induced damage. BPCBG at different doses was injected intramuscularly to male SD rats immediately after a single intraperitoneal injection of UO2(CH3COO)2. Twenty-four hours later uranium contents in urine, kidneys and femurs were measured by ICP-MS. After HK-2 cells were exposed to UO2(CH3COO)2 immediately or for 24 h followed by BPCBG treatment at different doses for another 24 or 48 h, the uranium contents in HK-2 cells were measured by ICP-MS, the cell survival was assayed by cell counting kit-8 assay, formation of micronuclei was determined by the cytokinesis-block (CB) micronucleus assay and the production of intracellular reactive oxygen species (ROS) was detected by 2',7'-dichlorofluorescin diacetate (DCFH-DA) oxidation. DTPA-CaNa3 was used as control. It was found that BPCBG at dosages of 60, 120, and 600 micromol kg(-1) resulted in 37%-61% increase in 24 h-urinary uranium excretion, and significantly decreased the amount of uranium retention in kidney and bone to 41%-31% and 86%-42% of uranium-treated group, respectively. After HK-2 cells that had been pre-treated with UO2(CH3COO)2 for 24 h were treated with the chelators for another 24 h, 55%-60% of the intracellular uranium was removed by 10-250 micromol L(-1) of BPCBG. Treatment of uranium-treated HK-2 cells with BPCBG significantly enhanced the cell survival, decreased the formation of micronuclei and inhibited the production of intracellular ROS. Although DTPA-CaNa3 markedly reduced the uranium retention in kidney of rats and HK-2 cells, its efficacy of uranium removal from body was significantly lower than that of BPCBG and it could not protect uranium-induced cell damage. It can be concluded that BPCBG effectively decorporated the uranium from UO2(CH3COO)2-treated rats and HK-2 cells, which was better than DTPA-CaNa3. It could also scavenge the uranium-induced intracellular ROS and protect against the uranium-induced cell damage. BPCBG is worth further investigation.

Identification of differentially expressed genes in female Culex pipiens pallens.

Culex pipiens pallens is the mosquito vector of a number of human pathogens such as Wuchereria bancrofti, Brugia malayi, and epidemic encephalitis B virus. Female C. pipiens pallens play an important role in transmitting pathogens by sucking blood, which is essential for reproduction. In the present study, a subtractive cDNA library for female C. pipiens pallens was constructed by the suppression subtractive hybridization (SSH) technique and then 100 clones from the female SSH library were sequenced and analyzed. Female-differentially expressed genes in C. pipiens pallens were screened using semiquantitative RT-PCR. The full-length cDNA of an EST sequence (fs68) that was specifically expressed in female C. pipiens pallens was characterized by 3' and 5' rapid amplification of cDNA ends (RACE). The characteristics of the female-specific gene were further analyzed using bioinformatics and Northern blot. It was shown that the female-specific gene was a previously uncharacterized gene and may encode a salivary peptide. This putative salivary peptide could be a very important molecule in the blood feeding of female C. pipiens pallens.

Bicuculline-insensitive GABA-gated Cl- channels in the larval nervous system of the moth Manduca sexta.

GABA-gated Cl(-) channels were studied in the nervous system of the larval tobacco hawk moth, Manduca sexta, using electrophysiology, (36)Cl(-) uptake into membrane microsacs and immunocytochemistry. A GABA-induced increase in Cl(-) conductance was recorded from a visually identifiable neurone ( fg1) in the desheathed frontal ganglion. The response was insensitive to the vertebrate GABA(A) receptor antagonist, bicuculline, but was blocked by picrotoxinin. Bicuculline-insensitive, picrotoxinin-sensitive, GABA-stimulated (36)Cl(-) uptake was also detected in membrane microsacs prepared from the isolated larval M. sexta nervous system. Such receptors appear to be the major type of GABA receptor in larval nervous system membrane microsac preparations. An antibody raised against a 17 amino acid peptide, based on the predicted C-terminus of the Drosophila GABA receptor subunit (RDL), stained not only cell bodies, including that of fg1, but also the neuropile in the frontal ganglion, indicating the existence of RDL-like GABA receptor subunits in neurones of this ganglion. Thus, bicuculline-insensitive GABA-gated Cl(-) channels are present in the larval nervous system of M. sexta.

Synthesis of osteogenic growth peptide and its synergetic effect with granulocyte colony stimulating factor.

Osteogenic growth peptide (OGP) has been synthesized through Fmoc solid phase synthesis procedure. The purity of synthetic OGP (sOGP) is over 98.6% identified by HPLC, the amino acid sequence and electro-spray mass spectroscopy are consistent with theoretical values. The synergetic effect of sOGP with recombinant human granulocyte-colony stimulating factor (rhG-CSF) on the hematopoiesis was investigated in normal mice. To assess the synergy of sOGP with rhG-CSF, two schemes were designed. In one scheme rhG-CSF was used at the last 8 days of a 13-day treatment with sOGP, while in the other one both cytokines were given concurrently for 10 days [sOGP, 0.5 nmol/day (mouse); rhG-CSF, 2 microg/day (mouse)]. Both schemes showed that sOGP remarkably synergized with rhG-CSF on increment of white blood cell number and lymphocyte number in peripheral blood without any change of red blood cell and platelet counts. Quantitative differential analysis of bone marrow and histological examination of the spleen and sternum showed that sOGP plus rhG-CSF did not cause abnormal hyperplasia, so sOGP is a very hopeful new drug to improve the effectiveness of clinical used rhG-CSF.