Influence of Active Tuberculosis on Chemokine and Chemokine Receptor Expression in HIV-Infected Persons

Tuberculosis (TB) is the major opportunistic infection of HIV-1-infected patients in developing countries. Concurrent infection with TB results in immune cells having enhanced susceptibility to HIV-1 infection, which facilitates entry and replication of the virus. Cumulative data from earlier studies indicate that TB provides a milieu of continuous cellular activation and irregularities in cytokine and chemokine circuits that favor viral replication and disease progression. To better understand the interaction of the host with HIV-1 during active tuberculosis, we investigated in vivo expression of the HIV-1 coreceptors, CCR5 and CXCR4, and circulating levels of the inhibitory �-chemokines, macrophage inflammatory protein-1-� (MIP-1�), macrophage inflammatory protein-1-� (MIP-1�), and regulated upon activation T cell expressed and secreted (RANTES), in HIV-positive individuals with and without active pulmonary tuberculosis. We found a significant decrease from normal in the fraction of CD4� T cells expressing CCR5 and CXCR4 in individuals infected with HIV. However, CCR5 and CXCR4 expression did not differ significantly between HIV patients with and without tuberculosis. Higher amounts of MIP-1�, MIP-1�, and RANTES were detected in plasma of HIV-1-positive individuals, particularly those with dual infection, although the increase was not found to be statistically significant

X-ray structures of two proteins belonging to Pfam DUF178 revealed unexpected structural similarity to the DUF191 Pfam family

<p>Abstract</p> <p>Background</p> <p>Pfam is a comprehensive collection of protein domains and families, with a range of well-established information including genome annotation. Pfam has two large series of functionally uncharacterized families, known as Domains of Unknown Function (DUFs) and Uncharacterized Protein Families (UPFs).</p> <p>Results</p> <p>Crystal structures of two proteins from <it>Deinococcus radiodurans </it>and <it>Streptomyces coelicolor </it>belonging to Pfam protein family DUF178 (ID: PF02621) have been determined using Selenium-Single-wavelength Anomalous Dispersion (Se-SAD). Based on the structure, we have identified the putative function for this family of protein.</p> <p>Conclusion</p> <p>Unexpectedly, we found that DUF178 Pfam is remarkably similar to Pfam family DUF191 suggesting that the sequence-based classification alone may not be sufficient to classify proteins into Pfam families.</p

Steady-state pharmacokinetics of Nevirapine in HIV-1 infected adults in India

Background and Objectives: A variety of demographic factors, sex, and degree of immunosuppression can influence antiretroviral drug concentratians. The authors studied the influence of immune status, sex, and body mass index (BMI) on the steady-state pharmacokinetics of nevirapine delivered as a fixed-dose combination in HIV-1-infected patients in India. Methods: Twenty-six HIV-l-infected adult patients undergoing treatment with nevirapine-based highly active antiretroviral therapy regimens participated in the study. Pharmacokinetic variables were compared between patients divided based an CD4 cell counts, sex, and BMI. Results: Patients with higher BMI had lower peak and trough concentration and exposure of nevirapine than those with lower BMI; none of the differences in the pharmacokinetic variables of nevirapine between the various patient groups was statistically significant. Conclusions: Patients' immune status, sex, or BMI had no impact on the pharmacokinetics of nevirapine. Plasma nevirapine concentrations were maintained within the therapeutic range of the drug in the majority of the patients

HIV-infected patients retreated for tuberculosis with intermittent Category II regimen--treatment outcome at 24-month follow-up.

BACKGROUND The management of tuberculosis re-treatment in HIV-infected individuals is complex. The clinical and radiological manifestations in this group and response to Category II treatment is not well described. METHODS We performed a prospective cohort study of HIV-infected patients retreated for TB due to failure, relapse or default after treatment, at Tuberculosis Research Centre, Chennai, between February 2001 to September 2005. The Category II regimen followed in the TB programme in India (RNTCP) was administered (2 months of Streptomycin (S), Ethambutol (E), INH (H), Rifampicin (R), Pyrazinamide (Z)/1 month of EHRZ/5 months of HRE all given thrice weekly). Antiretroviral treatment was not routinely available at that time. RESULTS Of the 42 patients enrolled, 35 (83%) were males. The mean age was 33.2 (SD-6.3) years. Cough was the commonest (67%) presenting symptom and opacities were the commonest (48%) radiographic occurrence. 31 patients were culture-positive at baseline, drug susceptibility results showed that 21 (68%) were fully susceptible to all first line drugs, four patients (13%) had MDR TB and four had resistance to INH alone. Among the 31 culture-positive patients, 15 patients (48.4%) completed treatment and were declared cured, of whom two subsequently relapsed. All four MDR patients died. Six patients who received ART, survived. CONCLUSION Only 50% of HIV-infected, ART-naive patients who were retreated for tuberculosis using an intermittent Category II regimen had a favourable response to treatment. Early detection of MDRTB and concurrent antiretroviral therapy could contribute to improved outcomes

Whole-Genome Sequencing of a Mycobacterium orygis Strain Isolated from Cattle in Chennai, India.

Here, we report the isolation of Mycobacterium orygis from dairy cattle in Chennai, India. Spoligotyping assigned the isolate to spoligotype 587 (ST587), which belongs to M. orygis This species was confirmed as M. orygis using whole-genome sequencing

Isolation and comparative genomics of Mycobacterium tuberculosis isolates from cattle and their attendants in South India

Funder: UK Medical Research Council, grant Reference number (MR/N501864/1)Abstract: The major human pathogen Mycobacterium tuberculosis is rarely reported to cause disease in other animals. Cases in livestock are thought to occur through contact with infected handlers, but previous studies evaluating putative livestock-human transmission used typing techniques with limited resolution. Here, we undertook cross-sectional surveillance for tuberculosis in 271 livestock handlers and 167 cattle on three farms in Chennai, India and defined the relatedness of cultured isolates using whole genome sequencing. Humans and livestock were screened for active mycobacterial infection, and opportunistic post-mortem examination was performed on comparative intradermal test-positive cattle that died. Four cattle and 6 handlers on two farms were culture-positive for M. tuberculosis; M. bovis was not isolated. All 10 isolates (one from each case) belonged to Lineage 1. Pairwise genome comparisons of single nucleotide polymorphism (SNP) differences ranged from 1 to 600 SNPs, but 3 isolate pairs were less than 5 SNPs different. Two pairs were from handlers and the third pair were from two cattle on the same farm. The minimum pairwise SNP difference between a cattle and human isolate was >250 SNPs. Our study confirms the presence of M. tuberculosis infection in cattle in India, sequencing of which characterised relatedness between human and cattle-derived isolates

Substrate Binding Mode and Its Implication on Drug Design for Botulinum Neurotoxin A

The seven antigenically distinct serotypes of Clostridium botulinum neurotoxins, the causative agents of botulism, block the neurotransmitter release by specifically cleaving one of the three SNARE proteins and induce flaccid paralysis. The Centers for Disease Control and Prevention (CDC) has declared them as Category A biowarfare agents. The most potent among them, botulinum neurotoxin type A (BoNT/A), cleaves its substrate synaptosome-associated protein of 25 kDa (SNAP-25). An efficient drug for botulism can be developed only with the knowledge of interactions between the substrate and enzyme at the active site. Here, we report the crystal structures of the catalytic domain of BoNT/A with its uncleavable SNAP-25 peptide 197QRATKM202 and its variant 197RRATKM202 to 1.5 Å and 1.6 Å, respectively. This is the first time the structure of an uncleavable substrate bound to an active botulinum neurotoxin is reported and it has helped in unequivocally defining S1 to S5′ sites. These substrate peptides make interactions with the enzyme predominantly by the residues from 160, 200, 250 and 370 loops. Most notably, the amino nitrogen and carbonyl oxygen of P1 residue (Gln197) chelate the zinc ion and replace the nucleophilic water. The P1′-Arg198, occupies the S1′ site formed by Arg363, Thr220, Asp370, Thr215, Ile161, Phe163 and Phe194. The S2′ subsite is formed by Arg363, Asn368 and Asp370, while S3′ subsite is formed by Tyr251, Leu256, Val258, Tyr366, Phe369 and Asn388. P4′-Lys201 makes hydrogen bond with Gln162. P5′-Met202 binds in the hydrophobic pocket formed by the residues from the 250 and 200 loop. Knowledge of interactions between the enzyme and substrate peptide from these complex structures should form the basis for design of potent inhibitors for this neurotoxin

Loss of quaternary structure is associated with rapid sequence divergence in the OSBS family

The rate of protein evolution is determined by a combination of selective pressure on protein function and biophysical constraints on protein folding and structure. Determining the relative contributions of these properties is an unsolved problem in molecular evolution with broad implications for protein engineering and function prediction. As a case study, we examined the structural divergence of the rapidly evolving o-succinylbenzoate synthase (OSBS) family, which catalyzes a step in menaquinone synthesis in diverse microorganisms and plants. On average, the OSBS family is much more divergent than other protein families from the same set of species, with the most divergent family members sharing <15% sequence identity. Comparing 11 representative structures revealed that loss of quaternary structure and large deletions or insertions are associated with the family’s rapid evolution. Neither of these properties has been investigated in previous studies to identify factors that affect the rate of protein evolution. Intriguingly, one subfamily retained a multimeric quaternary structure and has small insertions and deletions compared with related enzymes that catalyze diverse reactions. Many proteins in this subfamily catalyze both OSBS and N-succinylamino acid racemization (NSAR). Retention of ancestral structural characteristics in the NSAR/OSBS subfamily suggests that the rate of protein evolution is not proportional to the capacity to evolve new protein functions. Instead, structural features that are conserved among proteins with diverse functions might contribute to the evolution of new functions