UNDERSTANDING THE MECHANISM OF GENOMIC INSTABILITY DURING REPLICATIVE AGING IN BUDDING YEAST

Aging brings a gradual decline in molecular fidelity and biological functionality, resulting in age related phenotypes and diseases. Despite continued efforts to uncover the conserved aging pathways among eukaryotes, exact molecular causes of aging are still poorly understood. One of the most important hallmarks of aging is increased genomic instability. However, there remains much ambiguity as to the cause. I am studying the replicative life span (RLS) of the genetically tractable model organism Saccharomyces cerevisiae, or budding yeast using the innovative “mother enrichment program” as the method to isolate unparalleled numbers of aged yeast cells to investigate the molecular changes associated with aging. My goal is to determine the possible causes of loss of genomic integrity during replicative aging in budding yeast to gain potential insight into this vastly complex process. In my work presented here, I uncovered a global loss of cohesion in mitotically aged yeast cells and this most likely serves as the cause of increased rDNA instability and/or ERC accumulation as observed during aging. These events, in turn, influence the global genomic integrity in replicatively aged cells. Furthermore, I discovered a profound defect in double strand break (DSB) repair with aging due to limiting levels of key components of the homologous recombination machinery. This DSB repair defect in old cells limited the replicative lifespan, because restoration of DSB repair by overexpressing key HR proteins ameliorated age-associated changes, to extend lifespan. We propose that the limiting levels of repair factors and cohesin proteins impair the ability of the aged cells to counteract the increased burden of genomic damage accumulation coupled with chromosomal rearrangements and potentially chromosome loss, eventually to cross a threshold of genomic damage that is sensed by the cell to cause cessation of cell division marking the end of the replicative lifespan

Bioequivalence study of two formulations containing 400 mg dexibuprofen in healthy Indian subjects

Objective: This study presents the results of two-period, two-treatment crossover investigations on 24 healthy Indian male subjects to assess the bioequivalence of two oral formulations containing 400 mg of dexibuprofen (CAS 51146-56-6). An attempt was also made to study the pharmacokinetics of dexibuprofen in the local population of Indian origin.Method: Both of the formulations were administered orally as a single dose separated by a one-week washout period. The concentration of dexibuprofen in plasma was determined by a validated HPLC method with UV detection using carbamazepine as internal standard. The formulations were compared using the parameters area under the plasma concentration-time curve (AUC0-t), area under the plasma concentration-time curve from zero to infinity (AUC0-∞), peak plasma concentration (Cmax), and time to reach peak plasma concentration (tmax).Results: The results of this investigation indicated that there were no statistically significant differences between the logarithmically transformed AUC0-∞ and Cmax values of the two preparations. The 90 % confidence interval for the ratio of the logarithmically transformed AUC0-t, AUC0-∞ and Cmax were within the bioequivalence limit of 0.8-1.25 and the relative bioavailability of the test formulation was 99.04 % of that of reference formulationjok?.Conclusion: Thus, these findings clearly indicate that the two formulations are bioequivalent in terms of rate and extent of drug absorption. Both preparations were well tolerated with no adverse reactions observed throughout the study

Interactions of the cellular sumoylation system with influenza A virus and its non-structural protein NS1A (NS1A)

The most important current anti-influenza weapons, vaccination and antiviral drugs, can be rapidly rendered fully ineffective thanks to the virus’s high mutational rate, which produces viruses exhibiting new antigenic properties and structural proteins insensitive to the drug’s mechanism of action. One attractive alternative is to develop drugs that modulate the activity of cellular systems either required for viral growth or able to neutralize viral growth. Here we demonstrate that the cellular SUMOylation system, a post-translational modification involving the conjugation of the Small Ubiquitin-like MOdifier (SUMO) to specific protein targets using a Ubiquitin-like enzymatic cascade, interacts closely with influenza virus during infection and therefore provides new targets for the development of anti-influenza therapeutics targeting cellular components. Briefly, in vitro SUMOylation assays performed using in vitro synthesized viral proteins demonstrated that most influenza viral proteins are readily SUMOylated in vitro and therefore constitute potential SUMO targets. Transfection experiments leading to the over-expression of specific viral proteins in the presence or absence of various recombinant DNA constructs designed to modulate the activity of the cellular SUMOylation system demonstrated that various viral proteins are also SUMOylated when over-expressed in mammalian cells. Furthermore, experiments performed using recombinant adenoviruses able to modulate the activity of the cellular SUMOylation system demonstrated the SUMOylation of specific viral proteins during influenza infection. Finally, this study characterizes the SUMOylation of the nonstuctural viral protein NS1A, the best SUMO target of all the viral proteins produced during infection, explores some of the potential effects exerted by SUMOylation on the functions of this viral protein, and introduces the use of “artificial SUMO ligases” as an innovative method to increase the SUMOylation of specific targets in the cell and facilitate the characterization of the effects mediated by SUMOylation on protein function. Collectively, our studies provide new insights into the virus-host interactions established during influenza virus infections

Therapeutic application of PPE2 protein of Mycobacterium tuberculosis in inhibiting tissue inflammation

Abstract There is an increasing need to develop biological anti‐inflammatory agents that are more targeted, effective, and with lesser side effects as compared to conventional chemical drugs. In the present study, we found that Mycobacterium tuberculosis protein PPE2 and a synthetic derivative peptide can suppress the mast cell population and inhibit several vasoactive and fibrogenic mediators and pro‐inflammatory cytokines induced by mast cells in formalin‐induced tissue injury. PPE2 was found to inhibit transcription from the promoter of stem cell factor, important for mast cell maintenance and migration. Thus, PPE2/peptide can be used as a potent nonsteroidal therapeutic agent for the treatment of inflammation and tissue injury

Cooperative Calcium Phosphate Deposition on Collagen-Inspired Short Peptide Nanofibers for Application in Bone Tissue Engineering

In recent years, immense attention has been devoted over the production of osteoinductive materials. To this direction, collagen has a dominant role in developing hard tissues and plays a crucial role in the biomineralization of these tissues. Here, we demonstrated for the first time the potential of the shortest molecular pentapeptide domain inspired from collagen toward mineralizing hydroxyapatite on peptide fibers to develop bone-filling material. Our simplistic approach adapted the easy and facile route of introducing the metal ions onto the peptide nanofibers, displaying adsorbed glutamate onto the surface. This negatively charged surface further induces the nucleation of the crystalline growth of hydroxyapatite. Interestingly, nucleation and growth of the hydroxyapatite crystals lead to the formation of a self-supporting hydrogel to construct a suitable interface for cellular interactions. Furthermore, microscopic and spectroscopic investigations revealed the crystalline growth of the hydroxyapatite onto peptide fibers. The physical properties were also influenced by this crystalline deposition, as evident from the hierarchical organization leading to hydrogels with enhanced mechanical stiffness and improved thermal stability of the scaffold. Furthermore, the mineralized peptide fibers were highly compatible with osteoblast cells and showed increased cellular biomarkers production, which further reinforced the potential application toward effectively fabricating the grafts for bone tissue engineering

Pulmonary Function Studies of Healthy Non-smoking Male University Students of Kolkata, India — Revisited

Background: Pulmonary function tests (PFTs) need to be revisited in light of rapid economic growth and industrial development. Questions have been raised about the validity of existing population-specific norms for predicting PFTs, and therefore, the present study aimed to determine the applicability of existing norms for PFTs in young healthy non-smoking male university students of Kolkata. Methods: PFTs were carried out for 87 non-smoking male university students who were randomly sampled from the University of Calcutta, Kolkata, India. Results: The PFTs data obtained in this study did not show a significant variation with that obtained in a previous study. Significant (P < 0.001) differences in the forced expiratory volume in 1 s (FEV1%) and peak expiratory flow rate (PEFR) between the two studies may be attributed to differences in the age and body height, which exhibited significant correlations with the vital capacity (VC), forced vital capacity (FVC), FEV1, FEV1%, and PEFR. Regression equations have been computed to predict PFTs parameters from age and body height. Conclusion: Pulmonary function in the university students of Kolkata was found to have remained mostly unchanged in the last 24 years. The equations computed in this study are considered preferable owing to their substantially smaller standard error of estimate (SEE) than those proposed in the previous study

Use of Monoclonal Antibodies To Identify Phospholipase C as the Enterotoxic Factor of the Bifunctional Hemolysin-Phospholipase C Molecule of Vibrio cholerae O139

Two hybrid clones producing monoclonal antibodies (MAbs) raised against the purified enterotoxic hemolysin-phospholipase C (HlyPC) bifunctional molecule of a Vibrio cholerae O139 strain were used to study its enterotoxicity in relation to its hemolytic and enzymatic activities. Fab fragments of MAbs from ascites produced by the two hybrids neutralized the hemolytic activity of HlyPC, leaving the enzymatic activity unaffected. In ligated rabbit ileal loop and infant mouse intestine, the Fab fragments of the MAbs were not able to neutralize the enterotoxicity of HlyPC, suggesting that PC rather than Hly is the enterotoxic moiety of the molecule. The enterotoxicity of the purified PC molecule isolated from an Hly(−) spontaneous mutant of the HlyPC-producing parent strain further confirms this contention. The Hly molecule isolated from a PC(−) mutant was not diarrheagenic

Exploring scientific legitimacy of orthorexia nervosa: a newly emerging eating disorder

Eating disorders are a range maladaptive eating behaviours characterized by highly restrictive and unhealthy food intake patterns that lead to variety of psychiatric, physiological and health complications such as depression, anxiety, and personality disorders etc. Many of these psychological eating disorders such as anorexia nervosa or bulimia nervosa have been recognized as disease by the Diagnostic and Statistical Manual of Mental Disorders (DSM IV) of American psychiatric association. However there are many newly identified eating disorders which are yet to be recognized as disease by American psychiatric association. Orthorexia nervosa (ON) is one such unrecognized psychological eating disorder in which the person becomes obsessed with eating pure, healthy and right kinds of foods to improve health. There are no standard diagnostic criteria for ON and in recent times different researchers used different questionnaire to assess the presence of orthorexic characters. Many researchers have raised questions about the validity of ON as a unique disorder and many of them preferred to describe ON as a variant of existing eating or anxiety disorder. On the other hand many researchers believe that ON is an unique eating disorder different from other recognized eating disorders and it should be recognized as a disease in the planned fifth edition of the American Psychiatric Association's (APA) Diagnostic and Statistical Manual of Mental Disorders (DSM 5), due to be published in 2013. The review aims to highlight the present understanding about ON including its character, physiological and psychological consequences and different diagnostic features used by different researchers to evaluate ON. The review will compare ON with other recognized eating disorders, and assess the scientific validity of ON to be considered as a valid psychological eating disorder by American Psychiatric Association's (APA)