Genomic fingerprinting of bacteriocin-producer strains of Staphylococcus aureus

Among 363 strains of Staphylococcus aureus, 21 were shown to produce bacteriocins (Bac), antimicrobial peptides with potential biotechnological applications. This collection includes strains which are either isolated from food, patients and healthy cattle, or are involved in subclinical bovine mastitis. From these 21 strains, 17 were shown to carry closely-related 8.0-kb Bac plasmids encoding bacteriocins either identical to or similar to aureocin A70, a bacteriocin able to inhibit strains of Listeria monocytogenes, a food-borne pathogen. Such findings prompted us to investigate the genetic relationships among these Bac+ strains. To obtain more discriminatory results, a combined analysis of AP-PCR, rep-PCR, and a modified PCR technique that we designated SD-PCR was employed. The 17 Bac+ strains harboring 8.0-kb Bac plasmids exhibited seven fingerprint patterns. One such genotype was composed of 8 out of the 11 strains associated with bovine mastitis, which suggests the prevalence of a clone of Bac+ strains involved in this animal infection carrying 8.0-kb Bac plasmids. Our data support the assumption that Bac+ strains of S. aureus carrying genetically related 8.0-kb Bac plasmids do not belong to a single clone. It seems, therefore, that 8.0-kb Bac plasmids have spread horizontally among different S. aureus strains. There also seems to be genetic diversity among the remaining Bac+ strains analyzed.     

Salmonella enterica serovar typhimurium induces cell death in bovine monocyte-derived macrophages by early sipB-dependent and delayed sipB-independent mechanisms

It was previously demonstrated that Salmonella enterica serovar Typhimurium induces cell death with features of apoptosis in murine macrophages. Mice infected with Salmonella serovar Typhimurium develop systemic disease without diarrhea, whereas the infection in cattle and in humans is localized and characterized by diarrhea. Considering these clinical disease expression differences between mice and cattle, we investigated whether serovar Typhimurium is cytotoxic for bovine macrophages. Macrophages infected with serovar Typhimurium grown in the logarithmic phase quickly underwent cell death. Macrophages infected with stationary-phase cultures or with a mutant lacking sipB underwent no immediate cell death but did develop delayed cytotoxicity, undergoing cell death between 12 and 18 h postinfection. Both pathways were temporarily blocked by the general caspase inhibitor Z-VAD-Fmk and by the caspase 1 inhibitor Z-YVAD-Fmk. Comparisons of macrophages from cattle naturally resistant or susceptible to intracellular pathogens indicated no differences between these two genetic backgrounds in terms of susceptibility to serovar Typhimurium-induced cell death. We conclude that Salmonella serovar Typhimurium induces cell death in bovine macrophages by two distinct mechanisms, early sipB-mediated and delayed sipB-independent mechanisms.     

Apoptosis in breast carcinoma

Apoptosis may play a major role in determining tumor growth and aggressiveness. The aim of this study was to examine the relationship between apoptosis, expression of bcl-2 and p53 proteins, proliferation index, and other clinicopathological features of breast carcinoma. Sixty-five formalin-fixed paraffin-embedded tissue sections from invasive ductal breast carcinomas were studied for the presence of apoptosis by the terminaldeoxynucleotidyl-transferase-mediated dUTP-FITC nick end-labeling (TUNEL) method. Immunohistochemical methods were also used to determine the expression of estrogen receptor, Ki67, bcl-2 and p53 proteins. The number of apoptotic cells ranged from 2.0 to 236.0/10HPF (mean 36.26, median 28.0). The observation of 30 apoptotic cells/10HPF was more common in tumors > 3 cm, of histological grade III, with a high mitotic index, Ki67 index > or = 300, and p53 positivity; however, statistical significance was found only for the histological grade. Grade I and III tumors displayed an inverse association between the apoptotic index and bcl-2 and p53 protein expressions; grade I tumors frequently expressed bcl-2 (19/28), lacked p53 (20/28), and presented a low number of apoptotic cells (18/28), whereas grade III tumors tended to express p53 (12/17), lacked bcl-2 (13/17), and displayed a high number of apoptotic cells/10HPF (12/17). Multivariate analysis for survival revealed that estrogen receptors and apoptosis were independent variables. These data suggest that apoptosis, rather than proliferation index or expression of bcl-2 or p53 proteins, is an independent factor for the prognosis of survival.     

Shashi XLMR syndrome: report of a second family

This report describes a family with mental retardation in two brothers. The pedigree is consistent with either X-linked mental retardation or autosomal recessive inheritance. The clinical features consist of coarse face, prominent lower lip, large testes, and obesity. This same constellation of findings was observed in a family with X-linked mental retardation (XLMR) reported by Shashi et al. [2000: Am J Hum Genet 66:469-479]. Furthermore, haplotype analysis was consistent with localization of the Shashi XLMR syndrome in Xq26-q27. Thus, the family likely represents a second occurrence of the Shashi XLMR syndrome.     

Does the addition of recombinant LH in WHO group II anovulatory women over-responding to FSH treatment reduce the number of developing follicles? A dose-finding study

BACKGROUND: In anovulatory women undergoing ovulation induction, addition of recombinant human LH (rLH) to FSH treatment may promote the dominance of a leading follicle when administered in the late follicular phase. The objective of this study was to find the optimal dose of rLH that can maintain the growth of a dominant follicle, whilst causing atresia of secondary follicles. METHODS: Women with infertility due to anovulation and over-responding to FSH treatment were randomized to receive, in addition to 37.5 IU recombinant human FSH (rFSH), either placebo or different doses of rLH (6.8, 13.6, 30 or 60 microg) daily for a maximum of 7 days. The primary efficacy endpoint was the proportion of patients who had exactly one follicle > or = 16 mm on hCG day. RESULTS: Among 153 enrolled patients, the five treatment groups were similar in terms of baseline characteristics. The proportion of patients with exactly one follicle > or = 16 mm ranged from 13.3% in the placebo group to 32.1% in the 30 microg rLH group (P = 0.048). The pregnancy rate ranged from 10.3% in the 60 microg group to 28.6% in the 30 microg rLH group. Adverse events were similar between groups. CONCLUSIONS: In patients over-responding to FSH during ovulation induction, doses of up to 30 microg rLH/day appear to increase the proportion of patients developing a single dominant follicle (> or = 16 mm). Our data support the 'LH ceiling' concept whereby addition of rLH is able to control development of the follicular cohort.     

A porcine G9 rotavirus strain shares neutralization and VP7 phylogenetic sequence lineage 3 characteristics with contemporary human G9 rotavirus strains

Of five globally important VP7 (G) serotypes (G1-4 and 9) of group A rotaviruses (the single most important etiologic agents of infantile diarrhea worldwide), G9 continues to attract considerable attention because of its unique natural history. Serotype G9 rotavirus was isolated from a child with diarrhea first in the United States in 1983 and subsequently in Japan in 1985. Curiously, soon after their detection, G9 rotaviruses were not detected for about a decade in both countries and then reemerged in both countries in the mid-1990s. Unexpectedly, however, such reemerged G9 strains were distinct genetically and molecularly from those isolated in the 1980s. Thus, the origin of the reemerged G9 viruses remains an enigma. Sequence analysis has demonstrated that the G9 rotavirus VP7 gene belongs to one of at least three phylogenetic lineages: lineage 1 (strains isolated in the 1980s in the United States and Japan), lineage 2 (strains first isolated in 1986 and exclusively in India thus far), and lineage 3 (strains that emerged/reemerged in the mid-1990s). Currently, lineage 3 G9 viruses are the most frequently detected G9 strains globally. We characterized a porcine rotavirus (A2 strain) isolated in the United States that was known to belong to the P[7] genotype but had not been serotyped by neutralization. The A2 strain was found to bear serotype G9 and P9 specificities as well as NSP4 [B] and subgroup I characteristics. By VP7-specific neutralization, the porcine G9 strain was more closely related to lineage 3 viruses than to lineage 1 or 2 viruses. Furthermore, by sequence analysis, the A2 VP7 was shown to belong to lineage 3 G9. These findings raise intriguing questions regarding possible explanations for the emergence of variations among the G9 strains.     

Novel sequence variants in the TMC1 gene in Pakistani families with autosomal recessive hearing impairment

Though many hearing impairment genes have been identified, only a few of these genes have been screened in population studies. For this study, 168 Pakistani families with autosomal recessive hearing impairment not due to mutations in the GJB2 (Cx26) gene underwent a genome scan. Two-point and multipoint parametric linkage analyses were carried out. Twelve families had two-point or multipoint LOD scores of 1.4 or greater within the transmembrane cochlear expressed gene 1 (TMC1) region and were subjected to further screening with direct DNA sequencing. Five novel putatively functional non-synonymous sequence variants, c.830A>G (p.Y277C), c.1114G>A (p.V372M), c.1334G>A (p.R445H), c.2004T>G (p.S668R), and c.2035G>A (p.E679K), were found to segregate within seven families, but were not observed in 234 Pakistani control chromosomes. The variants c.830A>G (p.Y277C), c.1114G>A (p.V372M), and c.1334G>A (p.R445H) occurred at highly conserved regions and were predicted to lie within hydrophobic transmembrane domains, while non-synonymous variants c.2004T>G (p.S668R) and c.2035G>A (p.E679K) occurred in extracellular regions that were not highly conserved. There is evidence that the c.2004T>G (p.S668R) variant may have occurred at a phosphorylation site. One family has the known splice site mutation c.536 -8T>A. The prevalence of non-syndromic hearing impairment due to TMC1 in this Pakistani population is 4.4% (95%CI: 1.9, 8.6%). The TMC1 protein might have an important function in K(+) channels of inner hair cells, which would be consistent with the hypothetical structure of protein domains in which sequence variants were identified.     

From rafts to crafts: membrane asymmetry in moving cells

Many important biological events, including the leukocyte-mediated immune response, wound repair, axon guidance and developmental patterning, involve persistent cell movement towards a directional signal, a process termed chemotaxis. Establishment of functional and spatial cell polarity is an absolute requirement for this response. We propose that redistribution of specific membrane microdomains, termed rafts, during cell migration is a pivotal step in achieving polarity. On the one hand, partitioning of molecules into rafts might help to localize proteins at the front or the rear of moving cells, and on the other hand, rafts might function as platforms for local activation and coordination of the signaling pathways involved in cell migration.     

Outer membrane proteins from rough strains of four Brucella species.

Outer membrane proteins from 15 rough strains of Brucella abortus, B. ovis, B. canis, and B. melitensis were extracted with a dipolar detergent, and outer membrane proteins from selected strains were purified by anion exchange chromatography and gel filtration (Verstreate et al., Infect. Immun. 35:979-989, 1982). Outer membrane proteins produced two types of profiles on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. One type, demonstrated by B. abortus, B. ovis, and B. canis strains, contained the three predominant protein groups present in smooth B. abortus strains (Verstreate et al., Infect. Immun. 35:979-989, 1982): groups 1, 2 (porin [Douglas et al., Infect. Immun. 44:16-21]), and 3. B. melitensis strains demonstrated the second profile type, in which there was an additional band between groups 1 and 2. The relative proportion of porin was considerably lower in B. ovis, B. canis, and B. melitensis than in B. abortus. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis profiles could be used to distinguish B. abortus and B. melitensis from each other and from B. canis and B. ovis. The amino acid compositions of groups 2 and 3 from rough strains of B. abortus, B. canis, and B. melitensis were similar to those of corresponding proteins from smooth B. abortus strains. Zwittergent-soluble fractions from most rough strains contained antigen [b], which cross-reacted with group 2 from smooth B. abortus strains, and antigens [c] and [d], which cross-reacted with group 3 from smooth B. abortus strains. Antigen [a], shared by groups 2 and 3 (D. R. Verstreate and A. J. Winter, Infect. Immun. 46:182-187, 1984), was detected in most rough strains. None of these antigens were related to either rough or smooth lipopolysaccharide.     

Assessment of a rapid HIV test strategy during labor: a pilot study from Rio de Janeiro, Brazil

OBJECTIVES: To use two rapid human immunodeficiency virus (HIV) tests at labor, measure test acceptance and performance, and measure HIV prevalence in these women. METHODS: Between February and October 2000, two rapid tests (Determine; Abbott, Chicago, IL, U.S.A. and Double Check; Orgenics, Yavne, Israel) were used in three public maternities in Rio de Janeiro, Brazil. Enzyme-linked immunosorbent assay (ELISA) and Western blot (WB) analysis confirmed positive and discordant results. RESULTS: Of the 858 patients who were enrolled, the mean gestational age was 36 weeks (median = 39, mode = 40) and 17 (2%) refused testing. Of the 841 patients tested, 13 were positive by both tests, which represents a 1.5% prevalence (95% confidence interval: 0.7%-2.3%); all were confirmed by ELISA and WB analysis. Seven samples gave discordant results by the rapid tests; of these, six were ELISA-negative/WB-negative and one was ELISA-negative/WB-indeterminate. The positive predictive value for samples that were positive by both rapid tests simultaneously was 100%. CONCLUSIONS: Two rapid HIV tests used at labor were well accepted (98%). When the combined results of the two rapid tests (but not a single rapid test) were analyzed, this strategy was as efficient as the standard ELISA and WB HIV strategy for correctly classifying individuals.