Post by skytroll on Jul 22, 2008 19:16:08 GMT -5
Melanin production by Rhizobium meliloti GR4 is linked to nonsymbiotic plasmid pRmeGR4b: cloning, sequencing, and expression of the tyrosinase gene mepA.
Abstract
Melanin production by Rhizobium meliloti GR4 is linked to nonsymbiotic plasmid pRmeGR4b (140 MDa). Transfer of this plasmid to GR4-cured derivatives or to Agrobacterium tumefaciens enables these bacteria to produce melanin. Sequence analysis of a 3.5-kb PstI fragment of plasmid pRmeGR4b has revealed the presence of a open reading frame 1,481-bp that codes for a protein whose sequence shows strong homology to two conserved regions involved in copper binding in tyrosinases and hemocyanins. In vitro-coupled transcription-translation experiments showed that this open reading frame codes for a 55-kDa polypeptide. Melanin production in GR4 is not under the control of the RpoN-NifA regulatory system, unlike that in R. leguminosarum bv. phaseoli 8002. The GR4 tyrosinase gene could be expressed in Escherichia coli under the control of the lacZ promoter. For avoiding confusion with mel genes (for melibiose), a change of the name of the previously reported mel genes of R. leguminosarum bv. phaseoli and other organisms to mep genes (for melanin production) is proposed.
www.pubmedcentral.nih.gov/articlerender.fcgi?artid=206595
check out the image half way down the page:
Rhizobium meliloti GR4
myweb.scu.edu.tw/~94134052/02.htm
Phase-variable expression of an operon encoding extracellular alkaline protease, a serine protease homolog, and lipase in Pseudomonas brassicacearum; Chabeaud P et al.; The rhizobacterium Pseudomonas brassicacearum forms phenotypic variants which do not show extracellular protease and lipase activity . The operon encoding these enzymes, a serine protease homolog, and a type I secretion machinery was characterized . Transcriptional lacZ gene fusions revealed that the expression of the operon is under the control of phase variation.
www.bionewsonline.com/q/2/rhizobacteria_b.htm
Increased lipase anyone? mmmmmmmmm
LacZ gene fusions?
mmmm
Skytroll
Abstract
Melanin production by Rhizobium meliloti GR4 is linked to nonsymbiotic plasmid pRmeGR4b (140 MDa). Transfer of this plasmid to GR4-cured derivatives or to Agrobacterium tumefaciens enables these bacteria to produce melanin. Sequence analysis of a 3.5-kb PstI fragment of plasmid pRmeGR4b has revealed the presence of a open reading frame 1,481-bp that codes for a protein whose sequence shows strong homology to two conserved regions involved in copper binding in tyrosinases and hemocyanins. In vitro-coupled transcription-translation experiments showed that this open reading frame codes for a 55-kDa polypeptide. Melanin production in GR4 is not under the control of the RpoN-NifA regulatory system, unlike that in R. leguminosarum bv. phaseoli 8002. The GR4 tyrosinase gene could be expressed in Escherichia coli under the control of the lacZ promoter. For avoiding confusion with mel genes (for melibiose), a change of the name of the previously reported mel genes of R. leguminosarum bv. phaseoli and other organisms to mep genes (for melanin production) is proposed.
www.pubmedcentral.nih.gov/articlerender.fcgi?artid=206595
check out the image half way down the page:
Rhizobium meliloti GR4
myweb.scu.edu.tw/~94134052/02.htm
Phase-variable expression of an operon encoding extracellular alkaline protease, a serine protease homolog, and lipase in Pseudomonas brassicacearum; Chabeaud P et al.; The rhizobacterium Pseudomonas brassicacearum forms phenotypic variants which do not show extracellular protease and lipase activity . The operon encoding these enzymes, a serine protease homolog, and a type I secretion machinery was characterized . Transcriptional lacZ gene fusions revealed that the expression of the operon is under the control of phase variation.
www.bionewsonline.com/q/2/rhizobacteria_b.htm
Increased lipase anyone? mmmmmmmmm
LacZ gene fusions?
mmmm
Skytroll