Please wait, while we are loading the content...
Please wait, while we are loading the content...
| Content Provider | PubMed Central |
|---|---|
| Author | O'callaghan, R. J. Callegan, M. C. Moreau, J. M. Green, L. C. Foster, T. J. Hartford, O. M. Engel, L. S. Hill, J. M. |
| Abstract | Staphylococcus aureus corneal infection results in extensive inflammation and tissue damage. Our previous studies of bacterial mutants have demonstrated a role for alpha-toxin in corneal virulence. This study analyzes, by genetic rescue experiments, the virulence of mutants affecting alpha-toxin and beta-toxin activity and demonstrates the ocular toxicity of these purified staphylococcal proteins. Three types of isogenic mutants were analyzed: (i) mutants specifically deficient in alpha-toxin (Hla) or beta-toxin (Hlb), (ii) a mutant deficient in both Hla and Hlb, and (iii) a regulatory mutant, deficient in the accessory gene regulator (agr), that produces reduced quantities of multiple exoproteins, including alpha- and beta-toxins. Plasmids coding for Hla and Hlb (pDU1212 and pCU1hlb, respectively) were used to restore toxin activity to mutants specifically deficient in each of these toxins. Either corneas were injected intrastromally with logarithmic-phase S. aureus or purified alpha- or beta-toxins were administered to normal eyes. Ocular pathology was evaluated by slit lamp examination and myeloperoxidase activity of infiltrating polymorphonuclear leukocytes. Corneal homogenates were cultured to determine the CFU per cornea. Eyes infected with the wild-type strain developed significantly greater corneal damage than eyes infected with Agr-, Hlb-, or Hla- strains. Epithelial erosions produced by parent strains were not produced by Agr- or Hla- strains. Hlb+ strains, unlike Hlb- strains, caused scleral edema. Plasmid pDU1212 restored corneal virulence to strain DU1090 (Hla-), and plasmid pCU1hlb restored corneal virulence to strain DU5719 (Hlb-). Application of purified alpha-toxin produced corneal epithelial erosions and iritis, while application of beta-toxin caused scleral inflammation. These studies confirm the role of alpha-toxin as a major virulence factor during S. aureus keratitis and implicate beta-toxin, a mediator of edema, as a lesser contributor to ocular damage. |
| Starting Page | 1571 |
| File Format | |
| ISSN | 10985522 |
| e-ISSN | 10985522 |
| Journal | Infection and Immunity |
| Issue Number | 5 |
| Volume Number | 65 |
| Language | English |
| Publisher Date | 1997-05-01 |
| Access Restriction | Open |
| Subject Keyword | Research in Higher Education |
| Content Type | Text |
| Resource Type | Article |
| Subject | Infectious Diseases Parasitology Immunology Microbiology |
National Digital Library of India (NDLI) is a virtual repository of learning resources which is not just a repository with search/browse facilities but provides a host of services for the learner community. It is sponsored and mentored by Ministry of Education, Government of India, through its National Mission on Education through Information and Communication Technology (NMEICT). Filtered and federated searching is employed to facilitate focused searching so that learners can find the right resource with least effort and in minimum time. NDLI provides user group-specific services such as Examination Preparatory for School and College students and job aspirants. Services for Researchers and general learners are also provided. NDLI is designed to hold content of any language and provides interface support for 10 most widely used Indian languages. It is built to provide support for all academic levels including researchers and life-long learners, all disciplines, all popular forms of access devices and differently-abled learners. It is designed to enable people to learn and prepare from best practices from all over the world and to facilitate researchers to perform inter-linked exploration from multiple sources. It is developed, operated and maintained from Indian Institute of Technology Kharagpur.
Learn more about this project from here.
NDLI is a conglomeration of freely available or institutionally contributed or donated or publisher managed contents. Almost all these contents are hosted and accessed from respective sources. The responsibility for authenticity, relevance, completeness, accuracy, reliability and suitability of these contents rests with the respective organization and NDLI has no responsibility or liability for these. Every effort is made to keep the NDLI portal up and running smoothly unless there are some unavoidable technical issues.
Ministry of Education, through its National Mission on Education through Information and Communication Technology (NMEICT), has sponsored and funded the National Digital Library of India (NDLI) project.
| Sl. | Authority | Responsibilities | Communication Details |
|---|---|---|---|
| 1 | Ministry of Education (GoI), Department of Higher Education |
Sanctioning Authority | https://www.education.gov.in/ict-initiatives |
| 2 | Indian Institute of Technology Kharagpur | Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project | https://www.iitkgp.ac.in |
| 3 | National Digital Library of India Office, Indian Institute of Technology Kharagpur | The administrative and infrastructural headquarters of the project | Dr. B. Sutradhar bsutra@ndl.gov.in |
| 4 | Project PI / Joint PI | Principal Investigator and Joint Principal Investigators of the project |
Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon |
| 5 | Website/Portal (Helpdesk) | Queries regarding NDLI and its services | support@ndl.gov.in |
| 6 | Contents and Copyright Issues | Queries related to content curation and copyright issues | content@ndl.gov.in |
| 7 | National Digital Library of India Club (NDLI Club) | Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach | clubsupport@ndl.gov.in |
| 8 | Digital Preservation Centre (DPC) | Assistance with digitizing and archiving copyright-free printed books | dpc@ndl.gov.in |
| 9 | IDR Setup or Support | Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops | idr@ndl.gov.in |
|
Loading...
|