Members of the genus Streptococcus inhabit a variety of sites in humans and other animals and some species are prolific producers of proteinaceous antibiotics (bacteriocins). As little is known about ...(i) streptococci inhabiting domestic pets, and (ii) whether novel bacteriocin-producing streptococci can be isolated from domestic pets, the aim of this study is to address these gaps in the research literature. In this study, Streptococcus equinus MDC1, isolated from a healthy dog, was found to exhibit potent antibacterial activity against Micrococcus luteus in a simultaneous antagonism assay, suggesting that strain MDC1 produces a lantibiotic bacteriocin. The inhibitory activity spectrum of S. equinus MDC1, determined using agar-based deferred antagonism assays against >70 indicator strains, was found to be similar to that of nisin U (a lantibiotic produced by Streptococcus uberis). However, the spectra of the two bacteriocins differed by 23 strains, mainly with the MDC1 bacteriocin having no inhibitory activity towards certain streptococci of human origin (e.g., Streptococcus gordonii, Streptococcus anginosus, Streptococcus salivarius). The genome of S. equinus MDC1, which was sequenced completely using single-molecule real-time (SMRT) next-generation DNA sequencing technology, comprises a single 1,936,555-basepair chromosome containing seven copies of the ribosomal RNA operon, 69 tRNA genes and nearly 1900 putative coding sequences. Analysis of the MDC1 genome sequence using the bacteriocin detection algorithms BAGEL4 and antiSMASH revealed the location of a 13,164-basepair 11-gene locus, designated nmd, which encoded a mature nisin E peptide that differed from nisin U by only two amino acids (Ile15→Ala and Leu21→Ile) and an extra C-terminal asparagine residue, and the proteins required for post-translational modification of the bacteriocin, processing, export, and producer immunity. Despite the high homology (90.6% identity, 93.8% similarity) between nisin E and nisin U, there was considerably less homology (47.4–76.3% identity, 68.4–88.8% similarity) between the other proteins encoded by their respective biosynthetic loci. This new natural variant of nisin, called nisin E, represents the first nisin variant to be reported for S. equinus; additionally, its differences with nisin U may provide some insight into the amino acids that influence bacteriocin potency and killing spectrum.
Varicella vaccine was administered to seven children with corticosteroid-sensitive nephrotic syndrome. Immunization was not associated with any significant reactions or with increased frequency of ...relapse. The antibody response was, however, variable and a second dose was necessary before seroconversion was achieved in four patients. The findings indicate that immunization with varicella vaccine is safe in children with nephrotic syndrome in remission, but that a two-dose vaccine schedule should be considered. (J Pediatr 1997;131:688-90)
Although psoriasis is strongly associated with certain human leukocyte antigens (HLAs), evidence for linkage to HLA markers has been limited. The objectives of this study were (1) to provide more ...definitive evidence for linkage of psoriasis to HLA markers in multiplex families; (2) to compare the major HLA risk alleles in these families with those determined by previous case-control studies; and (3) to localize the gene more precisely. By applying the transmission/disequilibrium test (TDT) and parametric linkage analysis, we found evidence for linkage of psoriasis to HLA-C, -B, -DR, and -DQ, with HLA-B and -C yielding the most-significant results. Linkage was detectable by parametric methods only when marker-trait disequilibrium was considered. Case-control association tests and the TDT identified alleles belonging to the EH57.1 ancestral haplotype as the major risk alleles in our sample. Among individuals carrying recombinant ancestral haplotypes involving EH57.1, the class I markers were retained selectively among affecteds four times more often than among unaffecteds; among the few affected individuals carrying only the class II alleles from the ancestral haplotype, all but one also carried Cw6. These data show that familial and “sporadic” psoriasis share the same risk alleles. They also illustrate that substantial parametric linkage information can be extracted by accounting for linkage disequilibrium. Finally, they strongly suggest that a major susceptibility gene resides near HLA-C.
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