Inactivation by allelic exchange in clinical isolates of the emerging nosocomial pathogen Enterococcus faecium has been hindered by lack of efficient tools, and, in this study, transformation of clinical isolates was found to be particularly problematic. For this reason, a vector for allelic replacement (pTEX5500ts) was constructed that includes (i) the pWV01-based gram-positive repAts replicat...

Enteric bacteria possess two species of chorismate mutase which exist as catalytic domains on the amino termini of the bifunctional PheA and TyrA proteins. In addition, some of these organisms possess a third chorismate mutase, CM-F, which exists as a small monofunctional protein. The CM-F gene (denoted aroQ) from Erwinia herbicola was cloned and sequenced for the first time. A strategy for sel...

CAD (EC 1.1.1.195) catalyzes the conversion of cinnamaldehydes to the corresponding alcohols, the final step in the biosynthesis of the lignin precursors. CAD is considered one of the target enzymes for the modification of lignin biosynthesis (Whetten and Sederoff, 1991). This enzyme has been purified and characterized from severa1 plant species. cDNAs of CAD-encoding genes have been cloned fro...

Benzyl alcohol, benzaldehyde, benzoate, and anthranilate are metabolized via catechol, cis,cis-muconate, and the beta-ketoadipate pathway in Acinetobacter calcoaceticus ADP1 (BD413). Mutant strain ISA25 with a deletion spanning catBCIJF and unable to metabolize muconate further will not grow in the presence of an aromatic precursor of muconate. Growth on fumarate as the sole carbon source with ...

Most strains of E.coli contain two sequence specific methylases, Dam and Dem. The adenine residue of the sequence GATC is methylated at the N 6 position by the Dam methylase whereas the Dem methylase recognizes the sequences CC(A/T)GG methylating the internal cytosine at the C 5 position. The commercially available restriction enzyme AlwNl (New England Biolabs) has a recognition sequence CAGN 3...

The cholera toxin genes of Vibrio cholerae are encoded by the filamentous phage, CTXphi. Chromosomal CTXphi prophage DNA is often found flanked by copies of a related genetic element designated RS1, and RS1 DNA can be packaged into filamentous phage particles (designated RS1phi) by using the CTXphi morphogenesis genes. RS1phi is a satellite phage that further controls expression and disseminati...

Exposure of DNA to several proteins peroxidized by radiation-generated hydroxyl free radicals resulted in formation of crosslinks between the macromolecules, detected by retardation and broadening of DNA bands in agarose gels. This technique proved suitable for the study of crosslinking of DNA with peroxidized BSA, insulin, apotransferrin and alpha casein, but not with several other proteins, i...

Hepatopancreatic parvovirus (HPV) causes disease in several species of penaeid shrimp. Heavy infections may result in poor growth and reduced production for shrimp farmers. From one southern Thai shrimp pond with a high prevalence of HPV infection, 790 shrimp were sampled randomly and the hepatopancreas (HP) removed. Most HP were preserved in liquid nitrogen. However, every 10th HP (79 total) w...

Antigen P1, also called I/II, is one of the most abundant cell wall proteins of the mutans streptococci. It has been suggested that P1 may be involved in cell adherence to tooth surfaces and in sucrose-induced cell aggregation. As a first step toward fully understanding its biological functions, the P1 gene, which has been designated spaP1, from Streptococcus mutans NG5 (serotype c) has been cl...

Previous studies of the serum immunoglobulin G antibody response of periodontal patients have demonstrated significant reactivity to a cell surface or extracellular arginine-specific protease of Porphyromonas gingivalis which migrates as an approximately 50-kDa band on sodium dodecyl sulfate-polyacrylamide gels. In the present report, two forms of the enzyme (ArgI and ArgIA) with this electroph...