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1.
Pyrene and fluoranthene, when supplied as the sole carbon source, were not degraded by Burkholderia sp. VUN10013. However, when added in a mixture with phenanthrene, both pyrene and fluoranthene were degraded in liquid broth and soil. The amounts of pyrene and fluoranthene in liquid media (initial concentrations of 50 mg l−1 each) decreased to 42.1% and 41.1%, respectively, after 21 days. The amounts of pyrene and fluoranthene in soil (initial concentrations of 75 mg kg−1 dry soil each) decreased to 25.8% and 12.1%, respectively, after 60 days. None of the high molecular weight (HMW) polycylic aromatic hydrocarbons (PAHs) tested adversely affected phenanthrene degradation by this bacterial strain and the amount of phenanthrene decreased rapidly within 3 and 15 days of incubation in liquid broth and soil, respectively. Anthracene also stimulated the degradation of pyrene or fluoranthene by Burkholderia sp. VUN10013, but to a lesser extent than phenanthrene. The extent of anthracene degradation decreased in the presence of these HMW PAHs.  相似文献   
2.
A series of 14-deoxy-11,12-didehydroandrographolide analogues were synthesized from naturally occurring andrographolide and their cytotoxicity evaluated against nine cancer cell lines including cholangiocarcinoma. Analogues 5a and 5b exhibited the most potent cytotoxicity with ED50s of 3.37 and 3.08?μM on KKU-M213 cell lines and 2.93 and 3.27?μM on KKU-100 cell lines, respectively. Selective cytotoxicity on cholangiocarcinoma cell lines identified in this study highlight the importance of structural modification in the development of drugs for this cancer.  相似文献   
3.
Quantitative detection of the oil-degrading bacterium Acinetobacter sp. strain MUB1 was performed using the SoilMaster DNA Extraction Kit (Epicentre, Madison, Wisconsin) and hybridization probe based real-time PCR. The detection target was the alkane hydroxylase gene (alkM). Standard curve construction showed a linear relation between log values of cell concentrations and real-time PCR threshold cycles over five orders of magnitude between 5.4±3.0×106 and 5.4±3.0×102 CFU ml−1 cell suspension. The detection limit was about 540 CFU ml−1, which was ten times more sensitive than conventional PCR. The quantification of Acinetobacter sp. strain MUB1 cells in soil samples resulted in 46.67%, 82.41%, and 87.59% DNA recovery with a detection limit of 5.4±3.0×104 CFU g−1 dry soil. In this study, a method was developed for the specific, sensitive, and rapid quantification of the Acinetobacter sp. strain MUB1 in soil samples.  相似文献   
4.
In nature, several abiotic stresses occur simultaneously, leading to retarded growth and biochemical changes in microalgae, including the commercial cyanobacterium, Arthrospira platensis. To gain more understanding of stress response, we investigated the integrative effects of nitrogen depletion and high temperature stress on physiological changes of A. platensis C1. The results revealed that photosynthetic activities of the stressed cells were markedly reduced by more than a half in comparison to the non-stressed cells. Moreover, a reduction of biomass was observed within 24 h after prolonged exposure to combined stress of nitrogen depletion and high temperature. The total protein contents, including phycocyanin (PC), in the stressed cells, decreased rapidly within 8 h of incubation. This finding was concomitant with the increase in carbohydrate content. However, the accumulation of carbohydrates in the nitrogen depletion-treated cells was greater than that in the cells under the combined stress. Furthermore, the levels of polysaccharides increased only under long-term incubation under nitrogen depletion but not under the combined stress. In addition, the combination of nitrogen depletion and high temperature stress resulted in an increase in the proportion of linoleic acid but a decrease in γ-linolenic acid within 24 h. These results suggest that the response of A. platensis to the combined stress was different from the responses of cells to individual stress. The PC degradation, the increased carbohydrates, and the alteration in fatty acids profiles were required for physiological response to combined nitrogen depletion and high temperature stress of A. platensis C1.  相似文献   
5.

Background  

Prevention of a possible avian influenza pandemic necessitates the development of rapid diagnostic tests and the eventual production of a vaccine.  相似文献   
6.
Nontypeable Haemophilus influenzae (NTHi), an important human respiratory pathogen, frequently causes biofilm infections. Currently, resistance of bacteria within the biofilm to conventional antimicrobials poses a major obstacle to effective medical treatment on a global scale. Novel agents that are effective against NTHi biofilm are therefore urgently required. In this study, a series of natural and synthetic chalcones with various chemical substituents were evaluated in vitro for their antibiofilm activities against strong biofilm‐forming strains of NTHi. Of the test chalcones, 3‐hydroxychalcone (chalcone 8 ) exhibited the most potent inhibitory activity, its mean minimum biofilm inhibitory concentration (MBIC50) being 16 μg/mL (71.35 μM), or approximately sixfold more active than the reference drug, azithromycin (MBIC50 419.68 μM). The inhibitory activity of chalcone 8 , which is a chemically modified chalcone, appeared to be superior to those of the natural chalcones tested. Significantly, chalcone 8 inhibited biofilm formation by all studied NTHi strains, indicating that the antibiofilm activities of this compound occur across multiple strong‐biofilm forming NTHi isolates of different clinical origins. According to antimicrobial and growth curve assays, chalcone 8 at concentrations that decreased biofilm formation did not affect growth of NTHi, suggesting the biofilm inhibitory effect of chalcone 8 is non‐antimicrobial. In terms of structure–activity relationship, the possible substituent on the chalcone backbone required for antibiofilm activity is discussed. These findings indicate that 3‐hydroxychalcone (chalcone 8 ) has powerful antibiofilm activity and suggest the potential application of chalcone 8 as a new therapeutic agent for control of NTHi biofilm‐associated infections.  相似文献   
7.
The ability of Burkholderia sp. VUN10013 to degrade anthracene in microcosms of two acidic Thai soils was studied. The addition of Burkholderia sp. VUN10013 (initial concentration of 10(5) cells g(-1) dry soil) to autoclaved soil collected from the Plew District, Chanthaburi Province, Thailand, supplemented with anthracene (50 mg kg(-1) dry soil) resulted in complete degradation of the added anthracene within 20 days. In contrast, under the same test conditions but using autoclaved soil collected from the Kitchagude District, Chanthaburi Province, Thailand, only approximately 46.3% of the added anthracene was degraded after 60 days of incubation. In nonautoclaved soils, without adding the VUN10013 inocula, 22.8 and 19.1% of the anthracene in Plew and Kitchagude soils, respectively, were degraded by indigenous bacteria after 60 days. In nonautoclaved soil inoculated with Burkholderia sp. VUN10013, the rate and extent of anthracene degradation were considerably better than those seen in autoclaved soils or in uninoculated nonautoclaved soils in that only 8.2 and 9.1% of anthracene remained in nonautoclaved Plew and Kitchagude soils, respectively, after 10 days of incubation. The results showed that the indigenous microorganisms in the pristine acidic soils have limited ability to degrade anthracene. Inoculation with the anthracene-degrading Burkholderia sp. VUN10013 significantly enhanced anthracene degradation in such acidic soils. The indigenous microorganisms greatly assisted the VUN10013 inoculum in anthracene degradation, especially in the more acidic Kitchagude soil.  相似文献   
8.
Arthrospira platensis is a cyanobacterium that is extensively cultivated outdoors on a large commercial scale for consumption as a food for humans and animals. It can be grown in monoculture under highly alkaline conditions, making it attractive for industrial production. Here we describe the complete genome sequence of A. platensis C1 strain and its annotation. The A. platensis C1 genome contains 6,089,210 bp including 6,108 protein-coding genes and 45 RNA genes, and no plasmids. The genome information has been used for further comparative analysis, particularly of metabolic pathways, photosynthetic efficiency and barriers to gene transfer.  相似文献   
9.
This study investigated the biodegradation of high-molecular-weight polycyclic aromatic hydrocarbons (PAHs) in liquid media and soil by bacteria (Stenotrophomonas maltophilia VUN 10,010 and bacterial consortium VUN 10,009) and a fungus (Penicillium janthinellum VUO 10,201) that were isolated from separate creosote- and manufactured-gas plant-contaminated soils. The bacteria could use pyrene as their sole carbon and energy source in a basal salts medium (BSM) and mineralized significant amounts of benzo[a]pyrene cometabolically when pyrene was also present in BSM. P. janthinellum VUO 10,201 could not utilize any high-molecular-weight PAH as sole carbon and energy source but could partially degrade these if cultured in a nutrient broth. Although small amounts of chrysene, benz[a]anthracene, benzo[a]pyrene, and dibenz[a,h]anthracene were degraded by axenic cultures of these isolates in BSM containing a single PAH, such conditions did not support significant microbial growth or PAH mineralization. However, significant degradation of, and microbial growth on, pyrene, chrysene, benz[a]anthracene, benzo[a]pyrene, and dibenz[a,h]anthracene, each as a single PAH in BSM, occurred when P. janthinellum VUO 10,201 and either bacterial consortium VUN 10,009 or S. maltophilia VUN 10,010 were combined in the one culture, i.e., fungal-bacterial cocultures: 25% of the benzo[a]pyrene was mineralized to CO2 by these cocultures over 49 days, accompanied by transient accumulation and disappearance of intermediates detected by high-pressure liquid chromatography. Inoculation of fungal-bacterial cocultures into PAH-contaminated soil resulted in significantly improved degradation of high-molecular-weight PAHs, benzo[a]pyrene mineralization (53% of added [14C]benzo[a]pyrene was recovered as 14CO2 in 100 days), and reduction in the mutagenicity of organic soil extracts, compared with the indigenous microbes and soil amended with only axenic inocula.  相似文献   
10.
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