The dUTPase Enzyme Is Essential in Mycobacterium smegmatis

Thymidine biosynthesis is essential in all cells. Inhibitors of the enzymes involved in this pathway (e.g. methotrexate) are thus frequently used as cytostatics. Due to its pivotal role in mycobacterial thymidylate synthesis dUTPase, which hydrolyzes dUTP into the dTTP precursor dUMP, has been suggested as a target for new antitubercular agents. All mycobacterial genomes encode dUTPase with a mycobacteria-specific surface loop absent in the human dUTPase. Using Mycobacterium smegmatis as a fast growing model for Mycobacterium tuberculosis, we demonstrate that dUTPase knock-out results in lethality that can be reverted by complementation with wild-type dUTPase. Interestingly, a mutant dUTPase gene lacking the genus-specific loop was unable to complement the knock-out phenotype. We also show that deletion of the mycobacteria-specific loop has no major effect on dUTPase enzymatic properties in vitro and thus a yet to be identified loop-specific function seems to be essential within the bacterial cell context. In addition, here we demonstrated that Mycobacterium tuberculosis dUTPase is fully functional in Mycobacterium smegmatis as it rescues the lethal knock-out phenotype. Our results indicate the potential of dUTPase as a target for antitubercular drugs and identify a genus-specific surface loop on the enzyme as a selective target

Correcting autoimmune anomalies in autoimmune disorders by immunological means, employing the modified vaccination technique

Our research group has developed a new vaccination technique in experimental animals that has the potential of correcting autoimmune anomalies in humans such as autoimmune disorders, cancer, and chronic infections, both prophylactically and therapeutically. The vaccination method is called Modified Vaccination Technique (MVT). The MVT necessitates the introduction of a purified target antigen (ag) and a specific antibody (ab) against the target ag in the form of immune complex (IC) to evoke the desired immune response outcome by ab information transfer in the injected recipient. The injected IC produces the same class of ab in the host, with the same specificity against the target ag, as resides in the inoculum. The MVT promises to provide a means of upregulating beneficial immune events and downregulating undesirable immune responses in individuals, thereby re-establishing normalcy/tolerance to self. © 2009 Elsevier B.V. All rights reserved.link_to_subscribed_fulltex

Modified vaccination technique for prophylactic and therapeutic applications to combat endogenous antigen-induced disorders

Public health can be protected most effectively through vaccination programmes. However, while presently available vaccination techniques protects the individual by provoking immune responses against exogenous antigens (ags), such as those associated with certain bacteria and viruses, they cannot protect against or treat mishaps caused by endogenous ag. Recently, Barabas and colleagues have developed a new vaccination method, called modified vaccination technique (MVT), which allows the presentation of disease causing agents in such a way as to initiate and maintain desired immune response outcomes even in the context of mishaps associated with endogenous ag. For example, in an experimental autoimmune kidney disease, the MVT downregulated/terminated pathogenic immune responses that were causing morphological and functional changes of the kidney. The MVT promises, with appropriate case-specific modifications, both preventative and curative applications for ailments, such as endogenous ag initiated mishaps (i.e. autoimmune diseases and cancer) and diseases caused by chronic infection, that are presently only treatable with drugs. To achieve specific immune responses, purified components of the vaccine (ag and antibodies) must be produced and assembled into immune complexes having the potential of inducing predetermined corrective immune response outcomes. © 2010 Blackwell Publishing Ltd.link_to_subscribed_fulltex

Preventing And Treating Chronic Disorders Using The Modified Vaccination Technique.

It Is Anticipated That The Ultimate Solution For The Prevention And Termination Of Autoimmune Disorders Will Be Based On Somehow Manipulating The Cells Of The Immune System To Attain Antigen (Ag) Specific Downregulation And Termination. In The Last Few Years We Have Developed A New Vaccination Technique That We Call "Modified Vaccination Technique" (Mvt). It Has With Equal Effectiveness Both Prevented And Terminated Autoimmune Disease Causing Events In An Experimental Autoimmune Kidney Disease Model. We Expect That Our Technique Will Be Similarly Applicable To The Specific Treatment And Cure Of Numerous Other Chronic Disorders Presently Treated Only By Drugs. The Vaccine Is Composed Of Two Components, An Ag And A Specific Antibody Against It. When These Are Combined At Slight Ag Excess They Constitute A Vaccine Which Is Capable Of Treating Chronic Ailments By Redirecting Immune Response Outcomes In The Vaccinated Host. Both Components, Like Drugs, Will Have To Be Produced Ex Vivo In Order To Maintain Uniformity, Safety, Efficacy, And Specificity.link_to_subscribed_fulltex

Morphological changes in Salmonella Typhimurium caused by the lantibiotic bovicin HC5 in association with EDTA

Bacteriocins, particularly those produced by Gram-positive bacteria, have in recent years been considered promising antimicrobial agents to inhibit bacterial growth in food, and thus are potential food preservatives. These peptides generally exhibit a spectrum of action limited to Gram-positive bacteria. However, their action can be extended to Gram-negative bacteria through association with chelating agents. In the present study, we evaluated the occurrence of morphological changes on the cell envelope of Salmonella Typhimurium cells treated with bovicin HC5—a lantibiotic from Streptococcus bovis HC5—in association with EDTA. The morphological changes of the cells were visualized by atomic force microscopy (AFM), and the increase in cell membrane permeability was confirmed by the leakage of potassium ions (K+). The images displayed changes in the cell envelope, with increased surface roughness and a decreased cell volume. These changes indicate that EDTA plays a role in the destabilization of the outer membrane, allowing bovicin HC5 to act on the cytoplasmic membrane through the formation of pores, which was confirmed by the detection of potassium in the cell supernatant. These results suggest that bovicin HC5 combined with EDTA has potential for use on Salmonella cells