Several genetically stable mutants blocked in nikkomycin biosynthesis were obtained after the slightly germinated spores of Streptomyces ansochromogenes, a nikkomycin producer, were treated with ultra violet radiation...Several genetically stable mutants blocked in nikkomycin biosynthesis were obtained after the slightly germinated spores of Streptomyces ansochromogenes, a nikkomycin producer, were treated with ultra violet radiation. One of the mutants is the same in morpholotical differentiation as the wild type strain and is designated as NBB19. A DMA library was constructed using plasmid plJ702 as cloning vector, NBB19 as cloning recipient. A 6 kb DNA fragment which can genetically complement NBB19 was cloned when screening the library for antifungal activity. Sequence analysis showed that the 3 kb Bgl II-Sal I fragment contains one complete ORF (ORF1) and one partial ORF (ORF2). ORF1 is designated as sanA. sanA is 1 365 bp, encoding a protein consisting of 454 amino acid residues. Database searching indicated that sanA is homologous to the hypothetical methyltransferase in Pyrococcus horikoshli with 25% identities and 41% positives. Disruptant of sanA lost the ability to synthesize nikkomycin. It indicated that sanA is a novel gene which is essential for nikkomycin biosynthesis.展开更多
A 4.6 kb DNA fragment was cloned from the DNA library of Streptomyces ansochromogenes using a partial DNA fragment located in the downstream of promoter-PTH4 as probe. The experiments revealed that this DNA fragment c...A 4.6 kb DNA fragment was cloned from the DNA library of Streptomyces ansochromogenes using a partial DNA fragment located in the downstream of promoter-PTH4 as probe. The experiments revealed that this DNA fragment consists of sawD gene and a 1.4 kb Pvu II fragment which can accelerate mycelium formation of S. ansochromogenes. The nucleotide sequence of 1.4 kb DNA fragment was determined and analysed; the result indicated that the fragment contains one complete open reading frame (ORF) which encodes a protein with 213 amino acids, and this gene was designated as samfR. The deduced protein has 36% amino acid identities and 52% amino acid similarities in comparison with that encoded by hppR gene, which is involved in the regulation of catabolism for 3-(3-hydroxyphenyl) propionate (3HPP) in Rhodococcus gtoberulus . The function of samfR gene was studied using strategy of gene disruption, and the resulting samfR mutant failed to form aerial hyphae and spores, its development and differentiation stopped at the stage of substrate mycelium in contrast with wild type strain. The results showed that the samfR gene is closely related to S. ansochromogenes differentiation.展开更多
A new gene, scrX from Streptomyces coelicolor was cloned and sequenced. It consists of 660 base pair, encoding a peptide of 220 amino acids. There are three rare codons in scrX which are AAA, AAA and ATA. scrXgene may...A new gene, scrX from Streptomyces coelicolor was cloned and sequenced. It consists of 660 base pair, encoding a peptide of 220 amino acids. There are three rare codons in scrX which are AAA, AAA and ATA. scrXgene may be a typical differentiation regulator which was strictly controlled at translational level. The comparison of amino acids also revealed that ScrX belonged to Id R family which acted in transcriptional regulation of prokaryote. Studies on gene function by gene disruption and complementation indicated that scrX may play a positive regulation role in spore formation of Streptomyces coelicolor.A new gene, scrX from Streptomyces coelicolor was cloned and sequenced. It consists of 660 base pair, encoding a peptide of 220 amino acids. There are three rare codons in scrX which are AAA, AAA and ATA. scrXgene may be a typical differentiation regulator which was strictly controlled at translational level. The comparison of amino acids also revealed that ScrX belonged to Id R family which acted in transcriptional regulation of prokaryote. Studies on gene function by gene disruption and complementation indicated that scrX may play a positive regulation role in spore formation of Streptomyces coelicolor.展开更多
A partial DNA library of Streptomyces ansochromogenes 7100 was constructed by using plasmid plJ702 as vector and white mutant W19 as recipient. About 3 000 clones were obtained, two of which gave rise to the grey phen...A partial DNA library of Streptomyces ansochromogenes 7100 was constructed by using plasmid plJ702 as vector and white mutant W19 as recipient. About 3 000 clones were obtained, two of which gave rise to the grey phenotype as wild type 7100. The plasmids were isolated from two transformants. The result indicated that the 5.2 kb and 5.8 kb DNA fragments were inserted into plJ702. The resulting recombinant plasmids were designated as pNL-1 and pNL-2 respectively. The 1.25 kb Pstl l-Apa l DNA fragment from pNL-1 was recognized as its complementarity to W19 strain. The nucleotide sequence of the 3.0 kb Pst I DNA fragment including 1.25 kb was determined and analyzed. The result indicated that this DNA fragment contains one complete open reading frame (ORF1) which encodes a protein with 295 amino acid residues, and this gene was designated as sawB. The deduced protein has 81% amino acid identities in comparison with that encoded by whiH in Streptomyces coelicolor. The function of sawB gene was studied by using strategy of gene disruption, and the resulting sawB mutant failed to form spores and produced loosely coiled aerial hyphal. The result showed that sawB is closely related to hyphal coiling and sporulation in S. ansochromogenes, and also indicated that the sawB can complement whiH mutant (C119) to restore the grey phenotype of Streptomyces coelicolor J1501 (wild type).展开更多
文摘Several genetically stable mutants blocked in nikkomycin biosynthesis were obtained after the slightly germinated spores of Streptomyces ansochromogenes, a nikkomycin producer, were treated with ultra violet radiation. One of the mutants is the same in morpholotical differentiation as the wild type strain and is designated as NBB19. A DMA library was constructed using plasmid plJ702 as cloning vector, NBB19 as cloning recipient. A 6 kb DNA fragment which can genetically complement NBB19 was cloned when screening the library for antifungal activity. Sequence analysis showed that the 3 kb Bgl II-Sal I fragment contains one complete ORF (ORF1) and one partial ORF (ORF2). ORF1 is designated as sanA. sanA is 1 365 bp, encoding a protein consisting of 454 amino acid residues. Database searching indicated that sanA is homologous to the hypothetical methyltransferase in Pyrococcus horikoshli with 25% identities and 41% positives. Disruptant of sanA lost the ability to synthesize nikkomycin. It indicated that sanA is a novel gene which is essential for nikkomycin biosynthesis.
基金Project supported by the National Natural Science Foundation of China (Grant No. 39830010).
文摘A 4.6 kb DNA fragment was cloned from the DNA library of Streptomyces ansochromogenes using a partial DNA fragment located in the downstream of promoter-PTH4 as probe. The experiments revealed that this DNA fragment consists of sawD gene and a 1.4 kb Pvu II fragment which can accelerate mycelium formation of S. ansochromogenes. The nucleotide sequence of 1.4 kb DNA fragment was determined and analysed; the result indicated that the fragment contains one complete open reading frame (ORF) which encodes a protein with 213 amino acids, and this gene was designated as samfR. The deduced protein has 36% amino acid identities and 52% amino acid similarities in comparison with that encoded by hppR gene, which is involved in the regulation of catabolism for 3-(3-hydroxyphenyl) propionate (3HPP) in Rhodococcus gtoberulus . The function of samfR gene was studied using strategy of gene disruption, and the resulting samfR mutant failed to form aerial hyphae and spores, its development and differentiation stopped at the stage of substrate mycelium in contrast with wild type strain. The results showed that the samfR gene is closely related to S. ansochromogenes differentiation.
文摘A new gene, scrX from Streptomyces coelicolor was cloned and sequenced. It consists of 660 base pair, encoding a peptide of 220 amino acids. There are three rare codons in scrX which are AAA, AAA and ATA. scrXgene may be a typical differentiation regulator which was strictly controlled at translational level. The comparison of amino acids also revealed that ScrX belonged to Id R family which acted in transcriptional regulation of prokaryote. Studies on gene function by gene disruption and complementation indicated that scrX may play a positive regulation role in spore formation of Streptomyces coelicolor.A new gene, scrX from Streptomyces coelicolor was cloned and sequenced. It consists of 660 base pair, encoding a peptide of 220 amino acids. There are three rare codons in scrX which are AAA, AAA and ATA. scrXgene may be a typical differentiation regulator which was strictly controlled at translational level. The comparison of amino acids also revealed that ScrX belonged to Id R family which acted in transcriptional regulation of prokaryote. Studies on gene function by gene disruption and complementation indicated that scrX may play a positive regulation role in spore formation of Streptomyces coelicolor.
文摘A partial DNA library of Streptomyces ansochromogenes 7100 was constructed by using plasmid plJ702 as vector and white mutant W19 as recipient. About 3 000 clones were obtained, two of which gave rise to the grey phenotype as wild type 7100. The plasmids were isolated from two transformants. The result indicated that the 5.2 kb and 5.8 kb DNA fragments were inserted into plJ702. The resulting recombinant plasmids were designated as pNL-1 and pNL-2 respectively. The 1.25 kb Pstl l-Apa l DNA fragment from pNL-1 was recognized as its complementarity to W19 strain. The nucleotide sequence of the 3.0 kb Pst I DNA fragment including 1.25 kb was determined and analyzed. The result indicated that this DNA fragment contains one complete open reading frame (ORF1) which encodes a protein with 295 amino acid residues, and this gene was designated as sawB. The deduced protein has 81% amino acid identities in comparison with that encoded by whiH in Streptomyces coelicolor. The function of sawB gene was studied by using strategy of gene disruption, and the resulting sawB mutant failed to form spores and produced loosely coiled aerial hyphal. The result showed that sawB is closely related to hyphal coiling and sporulation in S. ansochromogenes, and also indicated that the sawB can complement whiH mutant (C119) to restore the grey phenotype of Streptomyces coelicolor J1501 (wild type).
