Oleic acid transformations by selected strains of Sphingobacterium thalpophilum and Bacillus cereus from composted manure

In a survey of 186 randomly selected microbial strains isolated from composted manure, 63 transformed oleic acid into three types of products: hydroxy fatty acid, fatty amide, and less polar oleyl lipid. Selection of oleic acid-transforming microorganisms was enhanced in nutrient agar supplemented with 0.1% (vol/vol) oleic acid at pH 7.2. Most of the 63 diverse isolates elicited inconsistent and poorly reproduced transformations. However, strains 142b (NRRL B-14797) transformed oleic acid to 10-hydroxystearic acid consistently, and strain 229b (NRRL B-14812) produced an octadecenamide. Taxonomic studies indicated that NRRL strain B-14797, possessing 1,3-dihydroxy-2-amino-15-methylhexadecane and sphinganine bases, was closely related to Sphingobacterium thalpophilum, and NRRL B-14812 was identified as Bacillus cereus.     

Application of bacterial magnetic particles as novel DNA carriers for ballistic transformation of a marine cyanobacterium

Summary Bacterial magnetite particles (BMPs) of 50 to 100nm diam were used as DNA carriers for the ballistic transformation of the marine cyanobacteriumSynechococcus. BMPs were bombarded into the cyanobacterial cells at several bombardment velocities using a particle gun. Successful transformation and gene expression were confirmed by Southern hybridization and CAT assay, respectively. The BMPs were also observed in the cyanobacterial cells by transmission electron microscopy. These results suggested that BMPs can be used as carriers for introducing DNA into bacterial cells.     

Amino acid sequences around 1, 2-epoxy-3-(p-nitrophenoxy)propane-reactive residues in rhizopus chinensis acid protease: homology with pepsin and rennin.

Two different peptides containing an aspartyl residue reactive with 1, 2-epoxy-3-(p-nitrophenoxy)propane (EPNP) in the acid protease from Rhizopus chinensis were isolated from a peptic digest of the EPNP-modified enzyme. One of the peptides was sequenced as Asp-Thr-Gly-Ser-Asp. The amino acid sequence had very high homology with those around the EPNP-reactive aspartyl residues in rennin (chymosin) [EC 3.4.23.4] and pepsin [EC 3.4.23.1]. The other peptide contained no methionine residue and gave the sequence: Asp-Thr-Gly-Thr-Thr-Leu. The N-terminal aspartyl residue of each peptide was deduced to be the EPNP-reactive site.     

Alteration of thermal stability of glucose oxidase associated with the redox states

By the method of differential scanning calorimetry, it was found that thermal stability of glucose oxidase was dependent on its redox states. The oxidized form showed an apparent denaturation temperature at 76°C and the denaturation enthalpy was approximately 865 kcal/mol. On reduction of the enzyme, the denaturation temperature increased by about 10°, but no significant change was seen in the denaturation enthalpy. The activation energies of the denaturation of the oxidized and the reduced enzymes were about 89 and 103 kcal/mol, respectively. These results may imply conformational changes in the catalytic turnover of this enzyme.