Modulation of adhesion of uropathogenic enterococcus faecalis to human epithelial cells in vitro by lactobacillus species

Two mammalian antimicrobial peptides, FA-LL-37 and cecropin P1, were tested for activity against six uropathogens and five Lactobacillus strains by broth microdilution assay. Both peptides inhibited Escherichia coli at 25 μM (FA-LL-39), and 1.56 μM (cecropin P1), Pseudomonas aeruginosa (12.5 μM, and 25 μM), and Klebsiella pneumoniae, (50 μM, and 1.56 μM), but not Enterococcus faecalis and Staphylococcus epidermidis. FA-LL-37 acted bacteriocidally against E. coli and bacteriostatically against the other two Gram-negative organisms. Cecropin P1 was bacteriocidal to all susceptible bacteria. Lactobacilli were resistant to both peptides, with the exception of poultry isolate Lactobacillus fermentum B-54, which was susceptible to FA-LL- 37 at 100 μM. The differential activities of these peptides toward Gram- negative uropathogens versus urogenital lactobacilli demonstrate their potential as a topical treatment for urinary tract infections. In addition, production of such peptides in vivo could be a natural mechanism to aid in the maintenance of the lactobacilli-dominated urogenital flora at the expense of pathogens. (C) 2000 Editions scientifiques et medicales Elsevier SAS

Oxalate-degrading enzymes from Oxalobacter formigenes: A novel device coating to reduce urinary tract biomaterial-related encrustation

The gastrointestinal and urogenital tracts are complex microbial habitats, which for the most part, are infection-free throughout life. Given the diversity of the world\u27s people, the enormous variation in diet and differences in climate, sexual practices, and exposure to antimicrobials which disrupt and change the flora, it is quite remarkable that naturally occurring infections are not even more common than reported. The composition, dynamics and structure of the normal flora biofilms appear to play a role in protecting the host from infectious upset. Specifically, lactobacilli and in the gut bifidobacteria, have been found to possess properties which enhance the host\u27s ability to compete against pathogens. The search for \u27good\u27 probiotic organisms continues, but recent findings of biosurfactant production and an ability to colonize the vagina, suggest that such strains do exist. Molecular typing has made it possible to follow the strains as they colonize or move through the host, and to investigate the genetic basis for their capabilities. Increasing concerns over drug resistance, and a growing desire by patients to have a more natural approach to their health management, is driving further scientific and clinical enquiry. This has led to some studies showing that potentially nutrients can be used to regulate, restore and stimulate the normal flora. Also of interest is the ability of probiotic organisms to reduce the risk of device-associated infections, and to deliver vaccines to the mucosal tissue. Subject to availability of grant funding for this non-traditional approach, the next 10 years should see some major breakthroughs of great benefit to the health of people around the globe

Two families of Rep-like genes that probably originated by interspecies recombination are represented in viral, plasmid, bacterial, and parasitic protozoan

Two families of genes related to, and including, rolling circle replication initiator protein (Rep) genes were defined by sequence similarity and by evidence of intergene family recombination. The Rep genes of circoviruses were the best characterized members of the "RecRep1 family." Other members of the RecRep1 family were Rep-like genes found in the genomes of the Canarypox virus, Entamoeba histolytica, and Giardia duodenalis and in a plasmid, p4M, from the Gram-positive bacterium, Bifidobacterium pseudocatenulatum. The "RecRep2 family" comprised some previously identified Rep-like genes from plasmids of phytoplasmas and similar Rep-like genes from the genomes of Lactobacillus acidophilus, Lactococcus lactis, and Phytoplasma asteris. Both RecRep1 and RecRep2 proteins have a nucleotide-binding domain significantly similar to the helicases (2C proteins) of picorna-like viruses. On the N-terminal side of the nucleotide binding domain, RecRep1 proteins have a domain significantly similar to one found in nanovirus Reps, whereas RecRep2 proteins have a domain significantly similar to one in the Reps of pLS1 plasmids. We speculate that RecRep genes have been transferred from viruses or plasmids to parasitic protozoan and bacterial genomes and that Rep proteins were themselves involved in the original recombination events that generated the ancestral RecRep genes

Comparative High-Density Microarray Analysis of Gene Expression during Growth of Lactobacillus helveticus in Milk versus Rich Culture Medium

Lactobacillus helveticus CNRZ32 is used by the dairy industry to modulate cheese flavor. The compilation of a draft genome sequence for this strain allowed us to identify and completely sequence 168 genes potentially important for the growth of this organism in milk or for cheese flavor development. The primary aim of this study was to investigate the expression of these genes during growth in milk and MRS medium by using microarrays. Oligonucleotide probes against each of the completely sequenced genes were compiled on maskless photolithography-based DNA microarrays. Additionally, the entire draft genome sequence was used to produce tiled microarrays in which noninterrupted sequence contigs were covered by consecutive 24-mer probes and associated mismatch probe sets. Total RNA isolated from cells grown in skim milk or in MRS to mid-log phase was used as a template to synthesize cDNA, followed by Cy3 labeling and hybridization. An analysis of data from annotated gene probes identified 42 genes that were upregulated during the growth of CNRZ32 in milk (P < 0.05), and 25 of these genes showed upregulation after applying Bonferroni's adjustment. The tiled microarrays identified numerous additional genes that were upregulated in milk versus MRS. Collectively, array data showed the growth of CNRZ32 in milk-induced genes encoding cell-envelope proteinases, oligopeptide transporters, and endopeptidases as well as enzymes for lactose and cysteine pathways, de novo synthesis, and/or salvage pathways for purines and pyrimidines and other functions. Genes for a hypothetical phosphoserine utilization pathway were also differentially expressed. Preliminary experiments indicate that cheese-derived, phosphoserine-containing peptides increase growth rates of CNRZ32 in a chemically defined medium. These results suggest that phosphoserine is used as an energy source during the growth of L. helveticus CNRZ32

Genetic modification of photosynthesis with E. coli genes for trehalose synthesis

Improvement in photosynthesis per unit leaf area has been difficult to alter by breeding or genetic modification. We report large changes in photosynthesis in Nicotiana tabacum transformed with E. coli genes for the trehalose pathway. Significantly, photosynthetic capacity (CO2 assimilation at varying light and CO2, and quantum yield of PSII electron transport) per unit leaf area and per leaf dry weight were increased in lines of N. tabacum transformed with the E. coli gene ots4, which encodes trehalose phosphate synthase. In contrast, transformation with otsB, which encodes trehalose phosphate phosphatase or Trec, encoding trehalose phosphate hydrolase, produced the opposite effect. Changes in CO2 assimilation per unit leaf area were closely related to the amount and activity of Rubisco, but not to the maximum activities of other Calvin cycle enzymes. Alterations in photosynthesis were associated with trehalose 6-phosphate content rather than trehalose. When growth parameters were determined, a greater photosynthetic capacity did not translate into greater relative growth rate or biomass. This was because photosynthetic capacity was negatively related to leaf area and leaf area ratio. In contrast, relative growth rate and biomass were positively related to leaf area. These results demonstrate a novel means of modifying Rubisco content and photosynthesis, and the complexities of regulation of photosynthesis at the whole plant level, with potential benefits to biomass production through improved leaf area

Strains, isolated from the same children in different time points.

<p>Horizontal axis represent the age of the subject, rows represent the children, labels in the cells correspond to the isolated strains. Dotted lines connect similar strains.</p

Whole genome alignment of complete genome sequences using Mauve.

<p>Colored boxes, linear collinear blocks (LCB). White gaps, insertions and deletions. Position atop or below the horizontal line represents the direction of LCB.</p

Distribution of ortholog groups by the number of strains in which they are present.

<p>Ortholog groups were divided into three categories based on their prevalence.</p

Structure of CRISPR-Cas systems in <i>B</i>. <i>longum</i>.

<p>Each scheme represents a typical locus from one of the studied strains.</p