Increased expression of mitochondrial glycerophosphate dehydrogenase and antioxidant enzymes in prostate cancer cell lines/cancer

The involvement of mitochondrial glycerophosphate dehydrogenase (mGPDH) has previously been established in the production of ROS in prostate cancer cell lines (LNCaP, DU145, PC3 and CL1). The current study demonstrates that the mRNA level of mGPDH in prostate cancer cells is 3.3–8.9-fold higher compared to the normal prostate epithelial cell line, PNT1A. This is consistent with the enzymatic activity and protein level of mGPDH. However, cytochrome c oxidase (COX) activity is 2.9–3.2-fold down-regulated in androgen-independent prostate cancer cell lines. The level of antioxidant enzymes, catalase, MnSOD and CuZnSOD are up-regulated in prostate cancer cell lines. Furthermore, it was observed that the activity of mGPDH is significantly higher in liver tissues from all mice with cancer compared to liver tissues from control mice. These data suggest that the up-regulation of mGPDH, due to a highly glycolytic environment, contributes to the overall increase in ROS generation and may result in the progression of the cancer.     

The Escherichia coli genes sspA and rnk can functionally replace the Pseudomonas aeruginosa alginate regulatory gene algR2

The algR2 (also known as algQ) gene of Pseudomonas aeruginosa has previously been identified as being necessary for alginate production at 37°C. We have cloned two genes, from a cosmid library of Escherichia coli, which can restore mucoidy to an algR2 mutant of P. aeruginosa. The complementing regions of both cosmids were localized by subcloning restriction fragments. One of the E. coli genes identified here has not previously been described; we have named this gene rnk (regulator of nucleoside diphosphate kinase). It encodes a 14.9 kDa protein with no homo-logy to any other protein. The other gene, sspA, is a regulator involved in stationary-phase regulation in E. coli. Either gene will restore mucoidy to an algR2-deficient strain of P. aeruginosa. AlgR2 has been shown to regulate at least two enzymes, succinyl-CoA synthetase (Scs) and nucleoside diphosphate kinase (Ndk), which form a complex in P. aeruginosa. When we examined the ability of the E. coli analogues to regulate Ndk, we found that rnk but not sspA was able to restore Ndk activity to the P. aeruginosa algR2 mutant. Furthermore, rnk was able to restore growth of the algR2 mutant in the presence of Tween 20, which inhibits other Ndk-like activities.     

Successful ablation of a left-sided accessory pathway in a patient with coronary sinus atresia and arteriovenous fistula: clinical and developmental insights

Background and objectives

While radiofrequency ablation catheter ablation of accessory pathways is generally safe and effective, anatomic variants can cause considerable challenges in effecting cure. Our objective was to use an unusual case where coronary sinus was absent and arterial venous fistula was present and a left-sided pathway required mapping and ablation to develop a framework to approach difficult cases.

Method

A detailed literature search and review of contemporary cardiac embryology was undertaken to attempt and to explain a common developmental anomaly. Adjunctive approaches during the ablation procedure, including intracardiac ultrasound, were used to guide mapping and ablation despite the lack of coronary sinus access.

Results

The accessory pathway was successfully ablated using a transseptal approach and intracardiac ultrasound guided mapping of the mitral annulus. A potential common mechanism to explain the apparently disparate anatomic variants in this patient was formulated.

Conclusions

Cardiac conduction development is complex and accessory pathway conduction may occur in the setting of arteriovenous anomalies thus providing insights as to the cause of WPW syndrome. Successful mapping and targeted ablation of left-sided pathways may be accomplished even when coronary sinus access is not possible.     

Role of glycosylation in structure and stability of Erythrina corallodendron lectin (EcorL): a molecular dynamics study

The effect of glycosylation on structure and stability of glycoproteins has been a topic of considerable interest. In this work, we have investigated the solution conformation of the oligosaccharide and its effect on the structure and stability of the glycoprotein by carrying out a series of long Molecular dynamics (MD) simulations on glycosylated Erythrina corallodendron lectin (EcorL) and nonglycosylated recombinant Erythrina corallodendron lectin (rEcorL). Our results indicate that, despite the similarity in overall three dimensional structures, glycosylated EcorL has lesser nonpolar solvent accessible surface area compared to nonglycosylated EcorL. This might explain the experimental observation of higher thermodynamic stability for glycosylated EcorL compared to nonglycosylated EcorL. Analysis of the simulation results indicates that, dynamic view of interactions between protein residues and oligosaccharide is entirely different from the static picture seen in the crystal structure. The oligosaccharide moiety had dynamically stable interactions with Lys 55 and Tyr 53, both of which are separated in sequence from the site of glycosylation, Asn 17. It is possible that glycosylation helps in forming long-range contacts between amino acids, which are separated in sequence and thus provides a folding nucleus. Thus our simulations not only reveal the conformations sampled by the oligosaccharide, but also provide novel insights into possible molecular mechanisms by which glycosylation can help in folding of the glycoprotein by formation of folding nucleus involving specific contacts with the oligosaccharide moiety.     

IGIPT - Integrated genomic island prediction tool

IGIPT is a web-based integrated platform for the identification of genomic islands (GIs). It incorporates thirteen parametric measures based on anomalous nucleotide composition on a single platform, thus improving the predictive power of a horizontally acquired region, since it is known that no single measure can absolutely predict a horizontally transferred region. The tool filters putative GIs based on standard deviation from genomic average and also provides raw output in MS excel format for further analysis. To facilitate the identification of various structural features, viz., tRNA integration sites, repeats, etc. in the vicinity of GIs, the tool provides option to extract the predicted regions and its flanking regions. AVAILABILITY: The database is available for free at http://bioinf.iiit.ac.in/IGIPT/     

Biochemical and physiological investigations on adenosine 5ʹ monophosphate deaminase from Plasmodium spp.

The interplay between ATP generating and utilizing pathways in a cell is responsible for maintaining cellular ATP/energy homeostasis that is reflected by Adenylate Energy Charge (AEC) ratio. Adenylate kinase (AK), that catalyzes inter‐conversion of ADP, ATP and AMP, plays a major role in maintaining AEC and is regulated by cellular AMP levels. Hence, the enzymes AMP deaminase (AMPD) and nucleotidases, which catabolize AMP, indirectly regulate AK activity and in‐turn affect AEC. Here, we present the first report on AMPD from Plasmodium, the causative agent of malaria. The recombinant enzyme expressed in Saccharomyces cerevisiae was studied using functional complementation assay and residues vital for enzyme activity have been identified. Similarities and differences between Plasmodium falciparum AMPD (PfAMPD) and its homologs from yeast, Arabidopsis and humans are also discussed. The AMPD gene was deleted in the murine malaria parasite P. berghei and was found to be dispensable during all stages of the parasite life cycle. However, when episomal expression was attempted, viable parasites were not obtained, suggesting that perturbing AMP homeostasis by over‐expressing AMPD might be lethal. As AMPD is known to be allosterically modulated by ATP, GTP and phosphate, allosteric activators of PfAMPD could be developed as anti‐parasitic agents.     

Biofilm-Forming Abilities of Listeria monocytogenes Serotypes Isolated from Different Sources

A total of 98 previously characterized and serotyped L. monocytogenes strains, comprising 32 of 1/2a; 20 of 1/2b and 46 of 4b serotype, from clinical and food sources were studied for their capability to form a biofilm. The microtiter plate assay revealed 62 (63.26%) strains as weak, 27 (27.55%) strains as moderate, and 9 (9.18%) strains as strong biofilm formers. Among the strong biofilm formers, 6 strains were of serotype 1/2a and 3 strains were of serotype 1/2b. None of the strain from 4b serotype exhibited strong biofilm formation. No firm correlation (p = 0.015) was noticed between any serotype and respective biofilm formation ability. Electron microscopic studies showed that strong biofilm forming isolates could synthesize a biofilm within 24 h on surfaces important in food industries such as stainless steel, ceramic tiles, high-density polyethylene plastics, polyvinyl chloride pipes, and glass. Cell enumeration of strong, moderate, and weak biofilm was performed to determine if the number of cells correlated with the biofilm-forming capabilities of the isolates. Strong, moderate, and weak biofilm showed 570±127× 10³ cells/cm², 33±26× 10³ cells/cm², 5±3× 10³ cells/cm², respectively, indicating that the number of cells was directly proportional to the strength of the biofilm. The hydrophobicity index (HI) analysis revealed higher hydrophobicity with an increased biofilm formation. Fatty acid methyl esterase analysis revealed the amount of certain fatty acids such as iso-C15:0, anteiso-C15:0, and anteiso-C17:0 fatty acids correlated with the biofilm-forming capability of L. monocytogenes. This study showed that different strains of L. monocytogenes form biofilm of different intensities which did not completely correlate with their serotype; however, it correlated with the number of cells, hydrophobicity, and amount of certain fatty acids.     

Has introduction of rapid drug susceptibility testing at diagnosis impacted treatment outcomes among previously treated tuberculosis patients in Gujarat,India?

Background

Revised National TB Control Programme (RNTCP) in India recommends that all previously-treated TB (PT) patients are offered drug susceptibility testing (DST) at diagnosis, using rapid diagnostics and screened out for rifampicin resistance before being treated with standardized, eight-month, retreatment regimen. This is intended to improve the early diagnosis of rifampicin resistance and its appropriate management and improve the treatment outcomes among the rest of the patients. In this state-wide study from Gujarat, India, we assess proportion of PT patients underwent rapid DST at diagnosis and the impact of this intervention on their treatment outcomes.

Methods

This is a retrospective cohort study involving review of electronic patient-records maintained routinely under RNTCP. All PT patients registered for treatment in Gujarat during January-June 2013 were included. Information on DST and treatment outcomes were extracted from ''presumptive DR-TB patient register'' and TB treatment register respectively. We performed a multivariate analysis to assess if getting tested is independently associated with unfavourable outcomes (death, loss-to-follow-up, failure, transfer out).

Results

Of 5,829 PT patients, 5306(91%) were tested for drug susceptibility with rapid diagnostics. Overall, 71% (4,113) TB patients were successfully treated - 72% among tested versus 60% among non-tested. Patients who did not get tested at diagnosis had a 34% higher risk of unsuccessful outcomes as compared to those who got tested (aRR - 1.34; 95% CI 1.20-1.50) after adjusting for age, sex, HIV status and type of TB. Unfavourable outcomes (particularly failure and switched to category IV) were higher among INH-resistant patients (39%) as compared to INH-sensitive (29%).

Conclusion

Offering DST at diagnosis improved the treatment outcomes among PT patients. However, even among tested, treatment outcomes remained suboptimal and were related to INH resistance and high loss-to-follow-up. These need to be addressed urgently for further progress.