12 research outputs found
There is more to accommodation of the eye than simply minimizing retinal blur.
Eyes of children and young adults change their optical power to focus nearby objects at the retina. But does accommodation function by trial and error to minimize blur and maximize contrast as is generally accepted? Three experiments in monocular and monochromatic vision were performed under two conditions while aberrations were being corrected. In the first condition, feedback was available to the eye from both optical vergence and optical blur. In the second, feedback was only available from target blur. Accommodation was less precise for the second condition, suggesting that it is more than a trial-and-error function. Optical vergence itself seems to be an important cue for accommodation
Large scale variation in Enterococcus faecalis illustrated by the genome analysis of strain OG1RF
A comparison of two strains of the hospital pathogen Enterococcus faecalis suggests that mediators of virulence differ between strains and that virulence does not depend on mobile gene element
Importance of the Collagen Adhesin Ace in Pathogenesis and Protection against Enterococcus faecalis Experimental Endocarditis
Ace is an adhesin to collagen from Enterococcus faecalis expressed conditionally after growth in serum or in the presence of collagen. Here, we generated an ace deletion mutant and showed that it was significantly attenuated versus wild-type OG1RF in a mixed infection rat endocarditis model (P<0.0001), while no differences were observed in a peritonitis model. Complemented OG1RFΔace (pAT392::ace) enhanced early (4 h) heart valve colonization versus OG1RFΔace (pAT392) (P = 0.0418), suggesting that Ace expression is important for early attachment. By flow cytometry using specific anti-recombinant Ace (rAce) immunoglobulins (Igs), we showed in vivo expression of Ace by OG1RF cells obtained directly from infected vegetations, consistent with our previous finding of anti-Ace antibodies in E. faecalis endocarditis patient sera. Finally, rats actively immunized against rAce were less susceptible to infection by OG1RF than non-immunized (P = 0.0004) or sham-immunized (P = 0.0475) by CFU counts. Similarly, animals given specific anti-rAce Igs were less likely to develop E. faecalis endocarditis (P = 0.0001) and showed fewer CFU in vegetations (P = 0.0146). In conclusion, we have shown for the first time that Ace is involved in pathogenesis of, and is useful for protection against, E. faecalis experimental endocarditis
Bioinformatic method for identifying surface-anchored proteins from gram-positive bacteria and proteins obtained thereby
A bioinformatic method is provided for identifying and isolating proteins with MSCRAMM®—like characteristics from Gram positive bacteria, such as Enterococcus, Staphylococcus, Streptococcus and Bacillus bacteria, which can then be utilized in methods to prevent and treat infections caused by Gram-positive bacteria. The method involves identifying from sequence information those proteins with a putative C-terminal LPXTG (SEQ ID NO:1) cell wall sorting signal and other structural similarities to MSCRAMM® proteins having the LPXTG-anchored cell wall proteins. The MSCRAMM® proteins and immunogenic regions therein that are identified and isolated using the present invention may be used to generate antibodies useful in the diagnosis, treatment or prevention of Gram positive bacterial infections.U
Bioinformatic method for identifying surface-anchored proteins from gram-positive bacteria and proteins obtained thereby
A bioinformatic method for identifying and isolating proteins and peptides with MSCRAMM?-like characteristics from Gram positive bacteria, such as Enterococcus, Staphylococcus, Streptococcus and Bacillus bacteria, and proteins and peptides obtained thereby are provided which can be utilized in methods to prevent and treat infections caused by Gram-positive bacteria. The method involves identifying from sequence information those proteins with a putative C-terminal LPXTG (SEQ ID NO:1) cell wall sorting signal and other structural similarities to MSCRAMM? proteins having the LPXTG-anchored cell wall proteins. The MSCRAMM? proteins and immunogenic regions therein that are identified and isolated using the present invention may be useful in the diagnosis, treatment or prevention of Gram positive bacterial infections.U
Bioinformatic method for identifying surface-anchored proteins from gram-positive bacteria and proteins obtained thereby
A bioinformatic method is provided for identifying and isolating proteins with MSCRAMM??like characteristics from Gram positive bacteria, such as Enterococcus, Staphylococcus, Streptococcus and Bacillus bacteria, which can then be utilized in methods to prevent and treat infections caused by Gram-positive bacteria. The method involves identifying from sequence information those proteins with a putative C-terminal LPXTG (SEQ ID NO:1) cell wall sorting signal and other structural similarities to MSCRAMM? proteins having the LPXTG-anchored cell wall proteins. The MSCRAMM? proteins and immunogenic regions therein that are identified and isolated using the present invention may be used to generate antibodies useful in the diagnosis, treatment or prevention of Gram positive bacterial infections.U
Bioinformatic method for identifying surface-anchored proteins from gram-positive bacteria and proteins obtained thereby
A bioinformatic method for identifying and isolating proteins and peptides with MSCRAMM?-like characteristics from Gram positive bacteria, such as Enterococcus, Staphylococcus, Streptococcus and Bacillus bacteria, and proteins and peptides obtained thereby are provided which can be utilized in methods to prevent and treat infections caused by Gram-positive bacteria. The method involves identifying from sequence information those proteins with a putative C-terminal LPXTG (SEQ ID NO:1) cell wall sorting signal and other structural similarities to MSCRAMM? proteins having the LPXTG-anchored cell wall proteins. The MSCRAMM? proteins and immunogenic regions therein that are identified and isolated using the present invention may be useful in the diagnosis, treatment or prevention of Gram positive bacterial infections.U
Importance of Two Enterococcus faecium Loci Encoding Gls-like Proteins for In Vitro Bile Salts Stress Response and Virulence
General stress proteins, Gls24 and GlsB, were previously shown to be involved in bile salts resistance of Enterococcus faecalis and in virulence. Here, we identified 2 gene clusters in Enterococcus faecium each encoding a homolog of Gls24 (Gls33 and Gls20; designated on the basis of their predicted sizes) and of GlsB (GlsB and GlsB1). The sequences of the gls33 and gls20 gene clusters from available genomes indicate distinct lineages, with those of hospital-associated CC17 isolates differing from non-CC17 by ∼7% and ∼3.5%, respectively. Deletion of an individual locus did not have a significant effect on virulence in a mouse peritonitis model, whereas a double-deletion mutant was highly attenuated (P < .004) versus wild-type. However, mutants lacking either gls33-glsB, gls20-glsB1, or both all exhibited increased sensitivity to bile salts. These results suggest that gls-encoded loci may be important for adaptation to the intestinal environment, in addition to being important for virulence functions
Relative Contributions of Ebp Pili and the Collagen Adhesin Ace to Host Extracellular Matrix Protein Adherence and Experimental Urinary Tract Infection by Enterococcus faecalis OG1RF
Conservation of Ebp-Type Pilus Genes among Enterococci and Demonstration of Their Role in Adherence of Enterococcus faecalis to Human Platelets â–¿ â€
Ebp are endocarditis- and biofilm-associated pili of Enterococcus faecalis that are also important in experimental urinary tract infections (UTIs). Our analyses, using available genomes, found that the ebp locus is unique to enterococci. In E. faecalis, the ebp locus is very highly conserved and only 1/473 E. faecalis isolates tested lacked ebpABC, while only 1.2% had the bee pilus locus. No other pilus-encoding operon was identified in 55 available genomes, indicating that the vast majority of E. faecalis strains (unlike Enterococcus faecium and streptococci) have a single pilus locus. Surface expression studies showed that Ebp pili were produced in vitro by 91/91 brain heart infusion (BHI) plus serum-grown E. faecalis isolates and that strain OG1RF expressed pili at even higher levels in rat endocarditis vegetations. However, Ebp expression was restricted to 30 to 72% of E. faecalis cells, consistent with a bistability mode of expression. We also evaluated E. faecalis interactions with human platelets and found that growth of E. faecalis in BHI plus serum significantly enhanced adherence to human platelets and that sortase deletion mutants (the ΔsrtA, Δbps, and ΔbpsΔsrtA mutants) were markedly defective. Further studies identified that Ebp pili, but not the microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) Ace and Fss2, mediate adherence of E. faecalis to platelets. Taken together, our data show that the immunogenic (in human endocarditis patients) and commonly expressed Ebp pili, which are known to be important for experimental endocarditis, are highly conserved and mediate adherence to platelets, suggesting that Ebp pili may be a reasonable immunotherapeutic target for prevention or possibly treatment of endocarditis caused by this species