A single Borrelia burgdorferi bacterium may contain six or more different 32 kb circular plasmids (cp32s). Although these plasmids are homologous throughout much of their sequences, two loci have been identified at which they can vary significantly. The cp32 plasmids and their relatives each contain two adjacent genes, orfC and orf3, that vary in sequence between plasmids found within clones of...

An outer membrane protein of 50 kDa (OprK) was overproduced in a siderophore-deficient mutant of Pseudomonas aeruginosa capable of growth on iron-deficient minimal medium containing 2,2'-dipyridyl (0.5 mM). The expression of OprK in the mutant (strain K385) was associated with enhanced resistance to a number of antimicrobial agents, including ciprofloxacin, nalidixic acid, tetracycline, chloram...

Streptomyces clavuligerus produces at least five different clavam metabolites, including clavulanic acid and the methionine antimetabolite, alanylclavam. In vitro transposon mutagenesis was used to analyze a 13-kb region upstream of the known paralogue gene cluster. The paralogue cluster includes one group of clavulanic acid biosynthetic genes in S. clavuligerus. Twelve open reading frames (ORF...

Walleye epidermal hyperplasia virus types 1 and 2 (WEHV1 and WEHV2, respectively) are associated with a hyperproliferative skin lesion on walleyes that appears and regresses seasonally. We have determined the complete nucleotide sequences and transcriptional profiles of these viruses. WEHV1 and WEHV2 are large, complex retroviruses of 12,999 and 13,125 kb in length, respectively, that are close...

Three genes encoding enzymes involved in the biosynthesis of pyrimidines have been found to constitute an operon in Lactococcus lactis. Two of the genes are the well-known pyr genes pyrDb and pyrF, encoding dihydroorotate dehydrogenase and orotidine monophosphate decarboxylase, respectively. The third gene encodes a protein which was shown to be necessary for the activity of the pyrDb-encoded d...

bla(VEB-6) was found on the Proteus mirabilis chromosome in a context similar to those of bla(VEB-1a) and bla(VEB-1b), in a truncated gene cassette flanked by 135-bp elements and duplications of the 3'-conserved segment of class 1 integrons. A linked aacA4-aadB-dfrA1-orfC cassette array includes components of Tn1331, illustrating the complex mosaicism of multiresistance regions.

In Streptococcus pneumoniae, a fermentative aerotolerant and catalase-deficient human pathogen, oxidases with molecular oxygen as substrate are important for virulence and for competence. The signal-transducing two-component systems CiaRH and ComDE mediate the response to oxygen, culminating in competence. In this work we show that the two-component MicAB system, whose MicB kinase carries a PAS...

The global dissemination of the multiply-antibiotic-resistant Salmonella enterica serovar Typhimurium DT104 clone with the resistance genes located in a class 1 integron, here designated In104, within genomic island SGI1 is a significant public health issue. Here, we have shown that SGI1 and variants of it carrying different combinations of resistance genes are found in several Salmonella enter...

Lipooligosaccharide (LOS) is a critical virulence factor of Neisseria meningitidis. A Tn916 insertion mutant, designated 469, was found to exhibit a markedly truncated LOS of 2.9 kDa when compared by Tricine/SDS-PAGE to the parental LOS (4.6 kDa). Electrospray mass spectrometry analysis of 469 LOS revealed that it consisted of the deep rough, heptose-deficient structure, Kdo(2)-lipid A. Sequenc...