Studies on bacteriorhodopsin gene and sequence of 16S rRNA encoding genes of halophilic archaea of Xingjiang Aibi Lake / 生物工程学报

One hundred and forty-eight strains of halophilic archaea were isolated from 40 samples of soil, lake water, and silt. To study and analyze the species and bacteriorhodopsin(BR) protein resource, partial DNA fragments encoding BR protein from helix C to helix G andl6S rRNA encoding genes from 6 strains of halophilic archaea were amplified by polymerase chain(PCR) , and their DNA sequences were determined. The results indicate that the reduced amino acid sequences of BR protein from helix C to helix G of ABDH11 is obviously different from those of other existing proteins. The results of homology analysis on BR gene andl6S rRNA and phylogenetic analysis on 16S rRNA show that strains ABDH10 and ABDH40 are novel members of genus Natronorubrum and Natrinema, respectively; the sequence of ABDH40 was obtained from GenBank and the number of sequence is AY989910. The protein from helix C to helix G of ABDH11 is significantly different from that of other strains.

Isolation and characterization of a novel strain of Natrinema containing a bop gene / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

A novel member of extremely halophilic archaea, strain AJ2, was isolated from Ayakekum Lake located in Altun Mountain National Nature Reserve of Xinjiang Uygur Autonomous Region in China. The strain AJ2 requires at least 10% (w/v) NaCl and grows 10% to 30% (optimum at 20%). Phylogenetic analysis based on 16S rDNA sequence comparison revealed that strain AJ2 clustered to three Natrinema species with less than 97.7% sequence similarities, suggesting AJ2 is a novel member of Natrinema. A bacteriorhodopsin-encoding (bop) gene was subsequently detected in the AJ2 genome using the polymerase chain reaction technique. The cloning and sequencing of a 401 base pairs fragment indicated the deduced amino acid sequence of bop from AJ2 is different from that reported for bacteriorhodopsins. This is the first reported detection of a bop gene in Natrinema.

Artificial Retina Mimbrane Assembly Utilzing Intelligent Materials: Biocompatibility and Electorphysiologic Features

In recent studies there have been various attempts at replacing a damaged retina with an artificial one. This paper outlines the assembly of an artificial retina membrane by incorporating a photorective protein bacteriorhodopsin into an electrochemically syntheszed conducting polymer polypyrrole. An electrophysiologic test was conducted to evaluate the photoresponsiveness of the bacteriorhodopsin and rabbit eyes were used to examine the biocompatibility of the artificial retina. The electrophysiologic test analyzed both wave forms and amplitudes obtained by photostimulating the artificial retina membrane with various light intensites(0.2, 2, 20J). In the biocompatibility test, the artificial membrane was inserted into the anterior chambers(4 eyes) and vitreous cavities(8 eyes) of rabbits. The condition of the eyes was then observed for one month. At the end of the first moonth, the eyes were enucleated and a histological examination was carried out. The electrophysiologic study displayed negative reflection waves, which are characteristic in rhodpsin, and their amplitudes showed a correspondign increase with stronger light intensities. The results of the biocompatibility test demonstrated that inflammatory reactions were not prominent in either the anterior chambers or the vitreous cavities during the first month and the histological examinations revealed no specific findings. In conclusion, a membrane assembled utilizing an electroactive polymer and a phocial retina.

Determination of total proton release in purple membrane suspension by umbelliferone fluorescence quenching technique.

A technique for determining total proton release from purple membrane suspension under steady illumination has been described. Illuminated purple membrane is found to quench the fluorescence life-time of umbelliferone indicating the release of protons in the medium. Besides the "stoichiometric" release of protons from bacteriorhodopsin, there seems to be release of protons from sources other than protonated retinylidene Schiff base moiety also.