[Construction and Characterization of B850-Only LH2 Energy Transfer System in Purple Bacteria].

To seek microscopic molecular mechanism of energy transfer and complex reconstitution in the photosynthesis, the conditions for construction of B850-only peripheral light-harvesting complex (LH2) and their properties were investigated using absorption, fluorescence spectroscopy, molecular sieve chromatography, ultrafiltration and sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) from the purple bacteria. The results indicated that bacteriochlorophylls (BChl) of B800 incubated in 10 mmo · L(-1) Tris-HCl (pH 8.0) buffer are selectively released from their binding sites of LH2 of Rhodobacter azotoformans (A-LH2) by 0.

[Influence of LDAO on the conformation and release of bacteriochlorophyll of peripheral light-harvesting complex (LH2) from Rhodobacter azotoformans].

The aim of this study is to reveal the interaction relationships between lauryl dimethylamine N-oxide (LDAO) and peripheral light-harvesting complex (LH2) as well as the influence of LDAO on structure and function of LH2. In the present work, the effects of LDAO on the conformation and release processes of bacteriochlorophyll (BChl) of LH2 when incubated under different temperature and pH in the presence and absence of LDAO were investigated by spectroscopy. The results indicated that (1) the presence of LDAO resulted in alterations in the conformation, alpha-helix content, and spectra of Tyr and B850 band of LH2 at room temperature and pH 8.

Molecular cloning and characterization of two major endoglucanases from Penicillium decumbens.

Two major endoglucanase genes (cel7B and cel5A) were cloned from Penicillium decumbens 114-2 using the method of modified thermal asymmetric interlaced polymerase chain reaction (TAIL-PCR). The result of Southern blotting suggested that P. decumbens has a single copy of the cel5A gene and a single copy of cel7B gene in its chromosomal DNA.

Catalytic activities of fungal oxidases in hydrophobic ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate-based microemulsion.

For hydrophobic ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF(6)]), an H(2)O-in-[BMIM][PF(6)] microemulsion could be formed in the presence of nonionic surfactant Triton X-100 (TX-100). In such a medium, both lignin peroxidase (LiP) and laccase could express their catalytic activity with the optimum molar ratio of H(2)O to TX-100 at 8.0 for LiP and >20 for laccase, and the optimum pH values at 3.

Catalytic performance of lignin peroxidase in a novel reverse micelle.

To enhance the catalytic activity of lignin peroxidase (LiP) in a reverse micelle, a synthesized two-tail nonionic surfactant N-gluconyl glutamic acid didecyl ester (GGDE) was used to formulate a novel reverse micelle. Based on the LiP catalyzed oxidation of veratryl alcohol (VA) in this novel GGDE/TritonX-100-cyclohexane-H(2)O reverse micelle, the effects of the size of the reverse micelle, the buffer pH, and the concentration of H(2)O(2) on the catalytic activity of LiP were investigated. Under the optimized conditions, the catalytic efficiency of LiP in the GGDE/TritonX-100 reverse micelle was 40 times higher than that in the AOT reverse micelle.

Sophorolipid produced from the new yeast strain Wickerhamiella domercqiae induces apoptosis in H7402 human liver cancer cells.

The effects of sophorolipid on the growth and apoptosis of H7402 human liver cancer cells were investigated. By treatment with sophorolipid, a dose- and time-dependent inhibition of cell proliferation was observed. The cells developed many features of apoptosis, including condensation of chromatin, nuclear fragmentation, and appearance of apoptotic bodies, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling positive cells were stained dark brown.

Degradation characteristics of two Bacillus strains on the Microcystis aeruginosa.

The degradation kinetics of strains P05 and P07 and the degradation effects of mixed strain on Microcystis aeruginosa were studied. The results showed that: (1) The degradation processes of strains P05 and P07 on Microcystis aeruginosa accorded with the first-order reaction model when the range of Chl-a concentration was from 0 to 1500 microg/L. (2) The initial bacterium densities had a strong influence on the degradation velocity.

[Studies on the catalytic performance of lignin peroxidase in nonionic reversed micelles].

Lignin peroxidase (LiP) hosted in Brij 30/cyclohexane/water nonionic reversed micelle could express its catalytic activity, but in Triton X-100/n-pentanol/cyclohexane/water nonionic reversed micelle LiP didn't show any catalytic activity. Some key factors that affected the catalytic activity of LiP in Brij 30 reversed micelle were studied at 20 degrees C. The optimum conditions were:omega0 = 8.

[Progress in the pathway engineering of ethanol fermentation from xylose utilising recombinant Saccharomyces cerevisiae].

Pathway engineering was the third generation of gene engineering. Its main goals were to change metabolic flux and open a new metabolic pathway in organism. Application of recombinant DNA methods to restructure metabolic networks can improve production of metabolite and protein products by altering pathway distributions and rates.

Novel cellulase profile of Trichoderma reesei strains constructed by cbh1 gene replacement with eg3 gene expression cassette.

To construct strains of the filamentous fungus Trichoderma reesei with low cellobiohydrolases while high endoglucanase activity, the P(cbh1)-eg3-T(cbh1) cassette was constructed and the coding sequence of the cellobiohydrolase I (CBHI) gene was replaced with the coding sequence of the eg3 gene by homologous recombination. Disruption of the cbh1 gene was confirmed by PCR, Southern dot blot and Western hybridization analysis in two transformants denoted as L13 and L29. The filter paper-hydrolyzing activity of strain L29 was 60% of the parent strain Rut C30, and the CMCase activity was increased by 33%.

Establishment of a xylose metabolic pathway in an industrial strain of Saccharomyces cerevisiae.

To produce an industrial strain of Saccharomyces cerevisiae that metabolizes xylose, we constructed a rDNA integration vector and YIp integration vector, containing the xylose-utilizing genes, XYL1 and XYL2, which encode xylose reductase (XR) and xylitol dehydrogenase (XDH) from Pichia stipitis, and XKS1, which encodes xylulokinase (XK) from S. cerevisiae, with the G418 resistance gene KanMX as a dominant selectable marker. The rDNA results in integration of multiple copies of the target genes.

A high-throughput model for screening anti-tumor agents capable of promoting polymerization of tubulin in vitro.

Aim: To establish a high-throughput model for screening anti-tumor agents capable of promoting the polymerization of tubulin in vitro.

Methods: Tubulin was prepared in different purity for two screening steps. The first step was a high-throughput screening (HTS) for a set of 1500 samples using the GTP-containing tubulin and the end-reading method.

Highly efficient conversion of lactate to pyruvate using whole cells of Acinetobacter sp.

On an industrial scale, the production of pyruvate at a high concentration from the cheaper lactate substrate is a valuable process. To produce pyruvate from lactate by whole cells, various lactate-utilizing microorganisms were isolated from soil samples. Among them, strain WLIS, identified as Acinetobacter sp.

16S-23S ribosomal DNA intergenic spacer regions in cellulolytic myxobacteria and differentiation of closely related strains.

The diversity of 16S-23S rDNA intergenic spacer regions (ISR) among cellulolytic myxobacterial strains was assayed. Agarose gel electrophoresis of PCR amplification products from ten strains shows that there are at least four copies of rRNA operons in the genus Sorangium, based on their size and restriction enzymatic digest maps. There are two sequence organization patterns: tRNA(Ile)-tRNA(Ala)-containing ISR and tRNA-lacking ISR.

[Hydrogen photoproduction from acetate by Rhodopseudomonas palustris].

Based on the characteristics of metabolism of photosynthetic bacteria and the major kinds of organic compounds produced in wastewater degradation, eleven kinds of organic compounds were chosen for hydrogen photoproduction using Rhodopseudomonas palustris Z strain. The maximal volumetric H2 productivity was obtained using acetate as the sole carbon source and electron donor. The kinetics of cell growth and H2 liberation, and the influences of several major limiting factors on photoevolution of H2 were examined using acetate as carbon source.