D-Tryptophan governs biofilm formation rates and bacterial interaction in P. mendocina and S. aureus

Biofilm genesis by Pseudomonas and Staphylococcus sp is associated with biofouling in natural settings. D-Tryptophan (DTrp) inhibits bacterial biofilms and have been proposed for biofouling control applications. In this study, D-Trp significantlyinhibited Pseudomonas mendocina and Staphylococcus aureus cell attachment (biofilm formation) rates on polystyrene96-well microtiter plates in comparison with L-Tryptophan (L-Trp) and mixtures of D-/L-Tryptophan (D-/L-Trp). Theinhibitory effect was greater on P. mendocina, where the rate of cell adherence was declined to 8.7 9 105 cells/h from8.0 9 106 cells/h (control) in P. mendocina. In S. aureus it was declined to 4.2 9 107 cells/h from 9.2 9 107 cells/h(control) at 1 mM concentration. It hindered the intracellular communication and adherence in both the strains, as confirmed by SEM and real time PCR analysis. Addition of D-Trp to preformed biofilms also caused partial disassembly. Intraand interbacterial aggregation were decreased subsequently upon treatment with D-Trp. It repressed the genes involved incell–cell communication, which could be responsible for the diminished biofilm formation of the selected strains. HenceD-Tryptophan has proved to be an effective strategy to control biofilm and may support in the development of surfacecoating technologies.

Evaluation of Mycobacterium tuberculosis 16 and 71 Heat Shock Proteins in the Cerebrospinal Fluid of Tuberculous Meningitis Patients.

Aims: To evaluate the efficiency of two potential Mycobacterium tuberculosis (M. tb) heat shock proteins (Hsps) towards the improvement of tuberculous meningitis (TBM) diagnosis. Study Design: The patients were divided into TBM (confirmed and suspected) and non TBM group. The cerebrospinal fluid (CSF) was collected and evaluated for M. tb Hsp 16 and 71.The Indirect ELISA results of M. tb Hsp 71 were compared with polymerase chain reaction (PCR). Place and Duration of Study: Biochemistry Research Laboratory, Central India Institute of Medical Sciences, Nagpur between June 2009 and July 2010. Methodology: 29 TBM and 22 non TBM CSF samples were collected. Indirect ELISA was performed for evaluating the, M. tb Hsp16 and Hsp71 in the collected samples, individually as well as in combination. The ELISA method for detection of M. tb Hsp 71 was also compared with in house PCR technique for TBM diagnosis. Results: The data analysis was done with MedCalc® Software. M. tb Hsp16 showed positivity of 58.62% and negativity of 68.18%. Similarly for M. tb Hsp71, positivity is 89.65% and negativity is 68.18%.The results of ELISA for M. tb Hsp71 was compared with PCR technique and concordance was also calculated. Of the Hsp ELISA positive group for M. tb Hsp71, 24 were PCR positive and 2 were PCR negative with the 92.30 % concordance in TBM patients and in non TBM patients the concordance was observed to be 93.30%. Use of the monoclonal antibody Hsp 71 appear preferable over individual use of M. tb Hsp 16 and combined use of both Hsp and yield optimum results. Conclusion: Our data suggest that the detection of M. tb Hsp 71 in the CSF sample of TBM patients can be useful for the diagnosis of TBM patients. These predictors, however, need further work to validate reliability.

Effect of repeat dose of BCG vaccination on humoral response in mice model.

BCG is the only vaccine presently available against tuberculosis but it is estimated to prevent only 5% of the all potentially vaccine-preventable deaths due to Tuberculosis. Keeping these in view the present study has been undertaken to evaluate the efficacy of BCG and the effect of repeat dose of BCG on antimycobacterial humoral response in mouse model. To improve BCG immunogenicity, specific anti-mycobacterial immune responses (anti-BCG titre and total IgG level) were evaluated in mouse model using boost immunization protocols with the BCG vaccine. Mice induced with a repeat dose of BCG showed an increased anti mycobacterial humoral response, which gradually declined few weeks after single dose of BCG administration. The results suggest improved efficacy of BCG vaccine by giving repeat dose of BCG that can enhance the level of immunoprotection against tuberculosis as opposed to a single BCG dose.

Secretory factors of human neuroblastoma (IMR-32) and human glioblastoma (U87MG) cell lines induce neurite outgrowths in PC12 cells.

Neurite outgrowth is essential for the communication of the nervous system. The rat Pheochromocytoma (PC12) cells are commonly used in the neuronal cell study. It is well known that exogenous stimuli such as Nerve Growth Factor (NGF) induce neurite outgrowth. In the present study it has been investigated whether or not the conditioned medium from human neuroblastoma cell line (IMR-32) and human glioblastoma cell line (U87MG) may augment neurite outgrowth in PC12 cells. PC12 were cultured with and without conditioned media of IMR-32 and U87MG. The result showed that both the conditioned media induce neurite outgrowth within 48 hr and stops further proliferation of PC12 cells. However no outgrowth was noted in PC12 cells incubated without conditioned medium. In conclusion, it is shown that both the conditioned media (IMR-32 and U87MG) have the potential to induce the neurite outgrowth in the PC12 cells.