Data/hora: 11/05/2024 03:43:30

Biblioteca(s): 	Embrapa Agrobiologia.	
Data corrente: 	11/12/1995	
Data da última atualização: 	24/07/2012	
Autoria: 	BALDANI, J. I.	
Título: 	Curing clover rhizobia of plasmids and defining the ecological and physiological functions of the plasmids.	
Ano de publicação: 	1990	
Fonte/Imprenta: 	Texas: Texas A&M University, dez. 1990. 155 p. Tese de Doutorado.	
Páginas: 	155 p.	
Série: 	Tese de doutorado	
Idioma: 	Inglês	
Notas: 	Tese de Doutorado. Orientada por: Richard W. Weaver.	
Conteúdo: 	This study was undertaken to define ecological and physiological functions of plasmids in three strains of Rhizobium leguminosarum bv. trifolii. Strains were characterized with respect to the number and size ofresident plasmids. Plasmid profiles indicated the presence of three, four and five plasmids in strains W14-2, W11-9 and W8-7, respectively. Only one plasmid per strain (pRtrW14-2d, pRtrW11-9a and pRtrW8-7c) hybridized with a probe pCHk12 carrying nif genes and therefore was termed psym. The other plasmids were classified as cryptic because of theirunknown functions. Curing of plasmids was accomplished by insertion ofTn5-SacB genes into plasmids and incubation of transconjugants either at 28oC or higher temperature (39oC to 44oC) on 5% sucrose plates.Manycured derivatives were selected simply by incubating transconjugants at 28oC and curing was independent of the size of the plasmid. Other plasmids were cured only with high temperatures. In two cases, pRtrW11-9c and pRtrW11-9c and pRtrW8-7d, plasmids were not eliminated from the cell. Evaluation of the phenotypic expression of cured derivatives in sterile soil subjected to low moisture (-1.5 MPa/28oC) or high temperature (38 to 42oC/-0.03 MPa) indicated that loss of plasmids affected survival of the bacteria. Low soil moisture reduced survival of some derivatives and was observed to be strain dependent. Elimination of plasmids pRtrW14-2a and pRtrw8-7bc increased survival of derivatives underlow soil moisture. High temperature was more detrimental than...	
Palavras-Chave: 	Genetic vector; Rizobio.	
Thesagro: 	Ecologia; Genética; Plasmídeo; Rhizobium; Vetor.	
Thesaurus Nal: 	ecology; plasmids.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Agrobiologia (CNPAB)	
Exemplares: 	CNPAB - (25262-1) - UPC - TS - -- - 589.95 - B175c - 1991.00001 - DIS
CNPAB - (25262-2) - UPC - TS - PP - 589.95 - B175c - 91.00001-2 - DIS