Phenotypic surface properties (aggregation, adhesion and biofilm formation) and presence of related genes in beneficial vaginal lactobacilli

AIMS

To evaluate the phenotypic expression of auto-aggregation, adhesion to mucin and biofilm formation of lactobacilli isolated from human vagina and the presence of related genes.

METHODS AND RESULTS

Seven different strains of three Lactobacillus species (Lactobacillus gasseri, Lactobacillus rhamnosus and Lactobacillus reuteri) were evaluated. The auto-aggregation property was determined by spectrophotometric assay and flow cytometry. Adhesion and biofilm formation were assayed by crystal violet staining. The presence of the genes encoding sortases, pilin subunits and surface proteins was evaluated by polymerase chain reactions. The two Lact. reuteri strains assayed showed high auto-aggregation, adhesion to mucin and biofilm formation ability. In these strains, the genes encoding three adhesion proteins were identified. In Lact. rhamnosus CRL (Centro de Referencia para Lactobacilos Culture Collection) 1332, pilus-encoding genes were detected. In all Lact. rhamnosus strains assayed, two genes encoding for other surface proteins related to adhesion and biofilm formation were detected.

CONCLUSIONS

The vaginal lactobacilli assayed exhibited phenotypic and genetic characteristics that were specific for each strain.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first study on auto-aggregation, adhesion and biofilm formation of vaginal Lactobacillus strains by phenotypic and genetic assays.

A novel mutation in the mitochondrial DNA tRNA Leu (UUR) gene associated with late-onset ocular myopathy

We identified a novel G3283A transition in the mitochondrial DNA tRNA(Leu (UUR)) gene in a patient with ptosis, ophthalmoparesis and hyporeflexia. Muscle biopsy showed cytochrome oxidase positive ragged-red fibers, and defects of complexes I, III and IV of the mitochondrial respiratory chain. The mutation was heteroplasmic in muscle of the proband, being absent in her blood. Ragged-red fibers harbored greater levels of mutant genomes than normal fibers. The G3283A mutation affects a strictly conserved base pair in the TPsiC stem of the gene and was not found in controls, thus satisfying the accepted criteria for pathogenicity.

Distinguishing self from nonself: immunogenicity of the murine H47 locus is determined by a single amino acid substitution in an unusual peptide

Histocompatibility (H) Ags are responsible for chronic graft rejection and graft vs host disease in solid tissue and bone marrow transplantation among MHC-matched individuals. Here we defined the molecular basis of self-nonself discrimination for the murine chromosome 7 encoded H47 histocompatibility locus, known by its trait of graft-rejection for over 40 years. H47 encodes a novel, highly conserved cell surface protein containing the SCILLYIVI (SII9) nonapeptide in its transmembrane region. The p7 isoleucine-to-phenylalanine substitution in SII9 defined the antigenic polymorphism and T cell specificity. Despite absence of the canonical consensus motif and weak binding to D(b) MHC I, both H47 peptides were presented to CTLs. However, unlike all the other known H loci, the relative immunogenicity of both H47 alleles varied dramatically and was profoundly influenced by neighboring H loci. The results provide insights into the peptide universe that defines nonself and the basis of histoincompatibility.

Positional cloning and molecular characterization of an immunodominant cytotoxic determinant of the mouse H3 minor histocompatibility complex

Immune responses to minor histocompatibility antigens are poorly understood and present substantial barriers to successful solid tissue and bone marrow transplantation among MHC-matched individuals. We exploited a unique positional cloning approach relying on the potent negative selection capability of cytotoxic T cells to identify the H3a gene responsible for immunodominant H2-Db-restricted determinants of the classically defined mouse autosomal H3 complex. The allelic basis for reciprocal H3a antigens is two amino acid changes within a single nonamer H2-Db-binding peptide. The H3a gene, now called Zfp106, encodes a 1888-amino acid protein with three zinc fingers and a beta-transducin domain consistent with DNA/protein binding. A region of ZFP106 is identical to a 600-amino acid sequence implicated in the insulin receptor signaling pathway.

Minors held by majors: the H13 minor histocompatibility locus defined as a peptide/MHC class I complex

The products of minor histocompatibility (H) loci are serious barriers to tissue transplantation even among major histocompatibility complex (MHC) identical individuals, frequently causing chronic graft rejection and graft versus host disease. Over 50 minor H loci map to mouse autosomal chromosomes but none are known at the molecular level. By expression cloning, we identified the H13 locus, a classical minor H locus first detected 30 years ago by the trait of graft rejection. The H13a allele is located on chromosome 2 and encodes a novel protein that yields the rare naturally processed nonapeptide SSVVGVWYL (SVL9) for presentation by the Db MHC class I molecule. The SVL9 peptide binds Db MHC despite the absence of the consensus binding motif, and a conservative methyl group substitution (Valine 4 <--> Isoleucine) explains why reciprocal T cell responses are elicited in H13a and H13b congenic strains.

Psychiatric morbidity following Hurricane Andrew

The nature of psychiatric morbidity in previously non-ill subjects from the area most affected by Hurricane Andrew was investigated at 6-12 months posthurricane. Preliminary associations of morbidity with personal and event-related risk factors were also determined. Fifty one percent (31/61) met criteria for a new-onset disorder, including posttraumatic stress disorder (PTSD) in 36%, major depression (MD) in 30%, and other anxiety disorders in 20%. Thirty four subjects (56%) had significant symptoms persisting beyond 6 months. Having sustained "severe damage" was the risk factor most strongly associated with outcome. Our data underscore the range of psychiatric morbidity related to a natural disaster, and suggest a relationship to chronic stressors.

The sea urchin sperm receptor for egg jelly is a modular protein with extensive homology to the human polycystic kidney disease protein, PKD1

During fertilization, the sea urchin sperm acrosome reaction (AR), an ion channel-regulated event, is triggered by glycoproteins in egg jelly (EJ). A 210-kD sperm membrane glycoprotein is the receptor for EJ (REJ). This conclusion is based on the following data: purified REJ binds species specifically to EJ dotted onto nitrocellulose, an mAb to REJ induces the sperm AR, antibody induction is blocked by purified REJ, and purified REJ absorbs the AR-inducing activity of EJ. Overlapping fragments of REJ cDNA were cloned (total length, 5,596 bp). The sequence was confirmed by microsequencing six peptides of mature REJ and by Western blotting with antibody to a synthetic peptide designed from the sequence. Complete deglycosylation of REJ followed by Western blotting yielded a size estimate in agreement with that of the mature amino acid sequence. REJ is modular in design; it contains one EGF module and two C-type lectin carbohydrate-recognition modules. Most importantly, it contains a novel module, herein named the REJ module (700 residues), which shares extensive homology with the human polycystic kidney disease protein (PKD1). Mutations in PKD1 cause autosomal dominant polycystic kidney disease, one of the most frequent genetic disease of humans. The lesion in cellular physiology resulting from mutations in the PKD1 protein remains unknown. The homology between REJ modules of the sea urchin REJ and human PKD1 suggests that PKD1 could be involved in ionic regulation.

A unique expression pattern for a sperm membrane protein during sea urchin spermatogenesis

Specific mRNAs coding for a 63 kDa sperm membrane protein (63-SMP) were localised in Strongylocentrotus purpuratus testis sections using in situ hybridisation techniques. 35S-labelled antisense RNA probes transcribed from a 766 base pair fragment of the gene coding for the 63-SMP hybridised to all spermatogenic cells in the basal germinal epithelia of testicular acini, except the most peripherally located (least differentiated) spermatogonia. No hybridisation to the luminally located mature spermatozoa or somatic cells of the testis was observed. Using monoclonal antibody J17/30 and indirect immunofluorescence techniques, the 63-SMP was localised to the same subset of spermatogenic cells that contain the 63-SMP mRNA, suggesting that expression of this gene is transcriptionally controlled. In combination with previous studies on the expression of sperm histones and sperm binding, these results show that multiple, perhaps sequential, classes of gene activity contribute to the differentiation of sea urchin sperm.

A GPI-anchored sea urchin sperm membrane protein containing EGF domains is related to human uromodulin

An Mr 63-kD sea urchin sperm flagellar membrane protein has been previously implicated as a possible receptor for egg jelly ligand(s) that trigger the sperm acrosome reaction (AR). The cDNA and deduced amino acid sequences of the 63-kD protein are presented. The open reading frame codes for a protein of 470 amino acids which contains a putative signal sequence of 25 residues. Western blots using antibodies to two synthetic peptides confirm the sequence to be that of the 63-kD protein. The mRNA is approximately 2,300 bases in length and the gene appears to be single copy. The protein is released from sperm membrane vesicles by treatment with phosphatidylinositol-specific phospholipase C, showing that it is anchored to the flagellar membrane by glycosylphosphatidyl inositol (GPI). Although we cannot demonstrate involvement of the 63-kD protein in the AR, it is of potential interest because it shares significant similarity with the developmentally expressed proteins crumbs, notch and xotch as well as human uromodulin over a region that includes two separate EGF repeats.