Isolation and partial characterization of Bacillus megaterium mutants deficient in poly(3-hydroxybutyrate) synthesis

1995 ◽  
Vol 41 (13) ◽  
pp. 77-79 ◽  
Author(s):  
Mirtha E. Floccari ◽  
Nancy I. López ◽  
Beatriz S. Méndez ◽  
Ursula Pieper Fürst ◽  
Alexander Steinbüchel
Keyword(s):  
Bacillus Megaterium ◽  
Allyl Alcohol ◽  
Chromatographic Analysis ◽  
Partial Characterization ◽  
Enzymatic Characterization ◽  
Gas Chromatographic Analysis ◽  
Selection For ◽  
Coa Reductase ◽  
Acetoacetyl Coa Reductase

Poly(3-hydroxybutyrate) (PHB)-negative mutants of Bacillus megaterium were isolated following mutagenesis with N-methyl-N′-nitro-N-nitrosoguanidine. Different strategies were used for isolation, including ultracentrifugation through sucrose gradients and selection for resistance to allyl alcohol. The mutants were detected on agar plates by staining the colonies with Sudan Black. Four mutants did not synthesize any PHB as revealed by gas chromatographic analysis. The enzymatic characterization showed no or extremely low synthase activity for all of the mutants. In contrast, no significant alterations were observed in the β-ketothiolase and the NADPH-dependent acetoacetyl-CoA reductase activities. All mutants sporulated in complete and minimal media.Key words: poly(3-hydroxybutyrate), synthase, mutants, Bacillus megaterium.

scholarly journals Crystal structure of acetoacetyl-CoA reductase from Rickettsia felis

2021 ◽  
Vol 77 (2) ◽  
pp. 54-60
Author(s):  
Justas V. Rodarte ◽  
Jan Abendroth ◽  
Thomas E. Edwards ◽  
Donald D. Lorimer ◽  
Bart L. Staker ◽  
...  
Keyword(s):  
Spotted Fever ◽  
Effective Means ◽  
Infectious Agent ◽  
Unknown Origin ◽  
Acid Synthesis ◽  
Rickettsia Felis ◽  
Wide Range ◽  
Coa Reductase ◽  
Acetoacetyl Coa Reductase

Rickettsia felis, a Gram-negative bacterium that causes spotted fever, is of increasing interest as an emerging human pathogen. R. felis and several other Rickettsia strains are classed as National Institute of Allergy and Infectious Diseases priority pathogens. In recent years, R. felis has been shown to be adaptable to a wide range of hosts, and many fevers of unknown origin are now being attributed to this infectious agent. Here, the structure of acetoacetyl-CoA reductase from R. felis is reported at a resolution of 2.0 Å. While R. felis acetoacetyl-CoA reductase shares less than 50% sequence identity with its closest homologs, it adopts a fold common to other short-chain dehydrogenase/reductase (SDR) family members, such as the fatty-acid synthesis II enzyme FabG from the prominent pathogens Staphylococcus aureus and Bacillus anthracis. Continued characterization of the Rickettsia proteome may prove to be an effective means of finding new avenues of treatment through comparative structural studies.

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