"Extremely halophilic bacteria are a large class of extreme microorganisms widely existing in high-concentration salt environments such as seawater salt-forming sites, salt lakes and even ancient marine sediments, and there are about 18 genera." Xiang Hua said, "Extreme halophilic bacteria are rich in extreme halophilic enzymes, special lipids, biosurfactants, protein antibiotics (halophilic bacteria), as well as important biological nano-materials' purple membrane' and biodegradable plastic precursor PHA. The purpose of our work now is to build a universal gene operation platform in extreme halophilic archaea, and to develop, transform and utilize important functional substances of extreme archaea. "
Complete sequencing and genetic analysis of the first extremely halophilic and alkalophilic archaea plasmid in the world were completed, and several cloning expression vectors with independent intellectual property rights were successfully constructed.
"We have made important progress in the molecular biology of extremely halophilic archaea, especially in the field of gene manipulation platform." Xiang Hua revealed that the researchers have isolated several plasmids from different groups of extremely halophilic archaea, conducted detailed molecular mechanism analysis, successfully constructed several cloned expression vectors with independent intellectual property rights, and applied for several national invention patents. Regarding its research process, Xiang Hua said, "We investigated about 30 strains of extremely halophilic archaea and isolated a new plasmid from one of them. The complete sequence determination showed that the plasmid was about 2.5kb in size and contained three open reading frames, which were located on the same strand of the plasmid. " According to reports, the study completed the complete sequencing and genetic analysis of the world's first extremely halophilic and alkalophilic archaea plasmid, and the paper has been published in the international professional journal Extremophiles of extreme microbiology; The new vector system based on this plasmid has successfully transformed a variety of extremely halophilic bacteria, and completed the analysis of restrictive modification systems of several recipient bacteria. The paper was also published in international magazines and applied for a national invention patent.
The possible resistance genes of halophilic bacteriocin were found for the first time in the world. The possible regulatory genes and transport processing genes of halophilic bacteriocin were cloned, and the cloning and complete sequencing of the smallest plasmid in extremely halophilic archaea were completed.
In another study, the staff investigated more than 60 strains of neutral extreme halophilic bacteria, found a new plasmid, and completed isolation, cloning, complete sequencing and GenBank registration. The research shows that this kind of plasmid may represent a new plasmid type of extremely halophilic archaea, which has high theoretical value. Because of the originality and clear application prospect of this work, the carrier receptor system constructed by it has also applied for national invention patent protection. In addition, the researchers of Xianghua research group also found, isolated and purified a new protein antibiotic with broad antibacterial spectrum and stable properties, and completed its physical and chemical properties, amino acid sequence and antibacterial spectrum analysis, and then completed its gene cloning and sequencing; Recently, the possible resistance genes of halophilic bacteriocin were discovered for the first time in the world. The heat-induced promoter of extreme halophilic archaea was cloned, its transcription initiation site was determined for the first time and its possible regulatory mechanism was analyzed. The research team also cloned the possible regulatory genes and transport processing genes of halophilic bacteriocin, and completed the cloning and complete sequencing of the smallest plasmid in extremely halophilic archaea.
Xiang Hua said that since the project started in June 2002, the research team has built two different series of carrier receptor systems and applied for two national invention patents. Published 3 papers in international professional SCI magazine; Seven new gene sequences (including about 12 new genes and more than 6 regulatory elements) were registered in GenBank. After the paper was published, it attracted the attention of international academic circles in this field and had a positive impact. Two laboratories of the University of Florida and the Russian Academy of Sciences also expressed their intention to cooperate.