Diversity of culturable sulfidogenic bacteria in two oil–water separation tanks in the north-eastern oil fields of India

Sulfidogenic communities in the production waters of onshore oil fields in north-eastern India were examined using a culturing approach. Production water samples were inoculated into medium selective for Sulfate reducing bacteria (SRB) and Thiosulfate Reducing Bacteria (TRB). The total number of viable sulfidogenic microorganisms in the samples obtained from the two production water tanks was approximately 10⁵ MPN ml^?1 (most probable number per ml). Most of the isolates were thermo-tolerant and could be grown between 40 and 45 °C. Hydrogen sulfide production by TRB was significantly higher than by SRB. Based on 16S rRNA gene sequencing, the isolates were grouped in nine different phylotypes. Phylogenetic analysis indicated that most of the SRB were affiliated with the phylum Proteobacteria, encompassing Gram-negative bacteria, belonging to the genera Desulfovibrio, Desulfomicrobium, and Desulfobulbus. However, five isolates grouped with the genus Desulfotomaculum were found to be gram-positive SRB. Most of the thiosulfate reducing isolates was affiliated with the phylum Firmicutes, including Clostridium and Fusibacter and also with the phylum Proteobacteria, including the genera Enterobacter and Citrobacter. Phylotypes related to Clostridium (69%) and Desulfovibrio (53%) dominated the community in the production water samples. This study demonstrates the diversity of the TRB and SRB that play a critical role in the souring mediated corrosion of the oil–water separation tanks in the north-eastern India oil fields.     

Mass spectrometric characterization of isoform variants of peanut (Arachis hypogaea) stem lectin (SL-I)

Matrix assisted laser desorption/ionization–time-of-flight (MALDI–TOF) mass spectrometric (MS) analysis of purified Arachis hypogaea stem lectin (SL-I) and its tryptic digests suggested it to be an isoformic glucose/mannose binding lectin. Two-dimensional gel electrophoresis of SL-I indicated six isoforms (A1–A6), which were confirmed by Western blotting and MALDI–TOF MS analysis. Comparative analysis of peptide mass spectra of the isoforms matched with A. hypogaea lectins with three different accession numbers (Q43376_ARAHY, Q43377_ARAHY, Q70DJ5_ARAHY). Tandem mass spectrometric (MS/MS) analysis of tryptic peptides revealed these to be isoformic variants with altered amino acid sequences. Among the peptides, the peptide T12 showed major variation. The ¹⁹⁹Val–Ser–Tyr–Asn²⁰² sequence in peptide T12 of A1 and A2 was replaced by ¹⁹⁹Leu–Ser–His–Glu²⁰² in A3 and A4 (T12′) while in A5 and A6 this sequence was ¹⁹⁹Val–Ser–Tyr–Val²⁰² (T12″). Peptide T1 showed the presence of ¹⁰Asn in the isoforms A1–A5 while in A6 this amino acid was replaced by ¹⁰Lys (T1′). Overall amino acid sequence as identified by MS/MS showed a high degree of similarity between A1, A2 and among A3, A4, A5. Carbohydrate binding domain and adenine binding site seem to be conserved.     

Prevalence and Predictors of Colposcopic-Histopathologically Confirmed Cervical Intraepithelial Neoplasia in HIV-Infected Women in India

Background

Prevalence estimates of cervical intraepithelial neoplasia (CIN) among HIV-infected women in India have been based on cervical cytology, which may have underestimated true disease burden. We sought to better establish prevalence estimates and evaluate risk factors of CIN among HIV-infected women in Pune, India using colposcopy and histopathology as diagnostic tools.

Methodology

Previously unscreened, non-pregnant HIV-infected women underwent cervical cancer screening evaluation including standardized diagnostic colposcopy by a gynecologist. Histopathologic confirmation was conducted among consenting women with clinical suspicion of CIN. The prevalence of CIN was evaluated by a composite diagnosis based on colposcopy and histopathology results. Multivariable ordinal logistic regression analysis was conducted to determine independent predictors of increasing severity of CIN.

Results

The median age of the n = 303 enrolled HIV-infected women was 30 years (interquartile range, 27–34). A majority of the participants were widowed or separated (187/303, 61.7%), more than one-third (114/302, 37.7%) were not educated beyond primary school, and nearly two-thirds (196/301, 64.7%) had a family per capita income of <1,000 Indian Rupees (∼US$22) per month. Cervical high-risk HPV-DNA was detected in 41.7% (124/297) of participants. The composite colposcopic-histopathologic diagnoses revealed no evidence of CIN in 220 out of 303 (72.6%) women, CIN1 in 33/303 (10.9%), CIN2 in 31/303 (10.2%), CIN3 in 18/303 (5.9%) and 1 (0.3%) woman was diagnosed with ICC. Thus, over a quarter of the participants [83/303: 27.7% (95% CI: 22.7–33.1)] had ≥CIN1 lesions and a sixth [50/303: 16.5% (95% CI: 12.2–21.9)] had evidence of advanced (≥CIN2) neoplastic disease. The independent predictors of increasing severity of CIN as revealed by a proportional odds model using multivariable ordinal logistic regression included (i) currently receiving antiretroviral therapy [adjusted odds ratios (aOR): 2.24 (1.17, 4.26), p = 0.01] and (ii) presence of cervical high-risk HPV-DNA [aOR: 1.93 (1.13, 3.28), p = 0.02].

Conclusions

HIV-infected women in Pune, India have a substantial burden of cervical precancerous lesions, which may progress to invasive cervical cancer unless appropriately detected and treated. Increased attention should focus on recognizing and addressing this entirely preventable cancer among HIV-infected women, especially in the context of increasing longevity due to antiretroviral therapy.     

Disordered microbial communities in the upper respiratory tract of cigarette smokers

Cigarette smokers have an increased risk of infectious diseases involving the respiratory tract. Some effects of smoking on specific respiratory tract bacteria have been described, but the consequences for global airway microbial community composition have not been determined. Here, we used culture-independent high-density sequencing to analyze the microbiota from the right and left nasopharynx and oropharynx of 29 smoking and 33 nonsmoking healthy asymptomatic adults to assess microbial composition and effects of cigarette smoking. Bacterial communities were profiled using 454 pyrosequencing of 16S sequence tags (803,391 total reads), aligned to 16S rRNA databases, and communities compared using the UniFrac distance metric. A Random Forest machine-learning algorithm was used to predict smoking status and identify taxa that best distinguished between smokers and nonsmokers. Community composition was primarily determined by airway site, with individuals exhibiting minimal side-of-body or temporal variation. Within airway habitats, microbiota from smokers were significantly more diverse than nonsmokers and clustered separately. The distributions of several genera were systematically altered by smoking in both the oro- and nasopharynx, and there was an enrichment of anaerobic lineages associated with periodontal disease in the oropharynx. These results indicate that distinct regions of the human upper respiratory tract contain characteristic microbial communities that exhibit disordered patterns in cigarette smokers, both in individual components and global structure, which may contribute to the prevalence of respiratory tract complications in this population.     

Preparation and evaluation of tubular micelles of pluronic lecithin organogel for transdermal delivery of sumatriptan

The present work focuses on the preparation and evaluation of lecithin organogel system of thermoreversible polymer pluronic F127, which would enhance the stability and absorption of sumatriptan succinate across the skin. Formulations were developed with and without co-surfactant (pluronic F127). The prepared organogels were evaluated for its appearance, organoleptic characteristics, and feel upon application, homogeneity, occlusivenes, washability, pH, viscosity, spreadability, gel transition temperature of formulations. The formulations were also evaluated for drug content, in vitro drug diffusion properties and skin irritation testing. In vivo evaluation of formulations was carried out by hot plate and writhing test method, and finally the optimized formulation was subjected to stability studies. The developed formulations were easily washable, smooth in feel, and showed no clogging which indicate superior texture of system. Formulation, containing pluronic showed greater spreadability and higher drug diffusion rate as compared to pluronic free organogel. Drug content of organogel formulations was in the range of 94-97%. The pH of the formulations was 6.48 ± 0.5 and 6.98 ± 0.1, reflecting no risk of skin irritation. Pluronic not only enhances the stability of organogel by increasing the viscosity (from 6,541 ± 234.76 to 7,826 ± 155.65 poise) but also increases the release of drug from 67.39 ± 1.53% to 74.21 ± 1.7%. The sumatriptan exhibits higher and long lasting antinociceptive effect as indicated by the persistent increase in reaction time in hot plate and inhibited abdominal contraction in acetic acid-induced writhing test (p < 0.05). The prepared optimized formulation was found to be stable without any significant changes at room temperature.     

Scaffolds in tissue engineering of blood vessels

Tissue engineering of small diameter (<5?mm) blood vessels is a promising approach for developing viable alternatives to autologous vascular grafts. It involves in vitro seeding of cells onto a scaffold on which the cells attach, proliferate, and differentiate while secreting the components of extracellular matrix that are required for creating the tissue. The scaffold should provide the initial requisite mechanical strength to withstand in vivo hemodynamic forces until vascular smooth muscle cells and fibroblasts reinforce the extracellular matrix of the vessel wall. Hence, the choice of scaffold is crucial for providing guidance cues to the cells to behave in the required manner to produce tissues and organs of the desired shape and size. Several types of scaffolds have been used for the reconstruction of blood vessels. They can be broadly classified as biological scaffolds, decellularized matrices, and polymeric biodegradable scaffolds. This review focuses on the different types of scaffolds that have been designed, developed, and tested for tissue engineering of blood vessels, including use of stem cells in vascular tissue engineering.     

Molecular profiling of single cancer cells and clinical tissue specimens with semiconductor quantum dots

Semiconductor quantum dots (QDs) are a new class of fluorescent labels with broad applications in biomedical imaging, disease diagnostics, and molecular and cell biology. In comparison with organic dyes and fluorescent proteins, quantum dots have unique optical and electronic properties such as size-tunable light emission, improved signal brightness, resistance against photobleaching, and simultaneous excitation of multiple fluorescence colors. Recent advances have led to multifunctional nanoparticle probes that are highly bright and stable under complex in vitro and in vivo conditions. New designs involve encapsulating luminescent QDs with amphiphilic block copolymers, and linking the polymer coating to tumor-targeting ligands and drug-delivery functionalities. These improved QDs have opened new possibilities for real-time imaging and tracking of molecular targets in living cells, for multiplexed analysis of biomolecular markers in clinical tissue specimens, and for ultrasensitive imaging of malignant tumors in living animal models. In this article, we briefly discuss recent developments in bioaffinity QD probes and their applications in molecular profiling of individual cancer cells and clinical tissue specimens.     

The 2.15 A crystal structure of Mycobacterium tuberculosis chorismate mutase reveals an unexpected gene duplication and suggests a role in host-pathogen interactions

Chorismate mutase catalyzes the first committed step toward the biosynthesis of the aromatic amino acids, phenylalanine and tyrosine. While this biosynthetic pathway exists exclusively in the cell cytoplasm, the Mycobacterium tuberculosis enzyme has been shown to be secreted into the extracellular medium. The secretory nature of the enzyme and its existence in M. tuberculosis as a duplicated gene are suggestive of its role in host-pathogen interactions. We report here the crystal structure of homodimeric chorismate mutase (Rv1885c) from M. tuberculosis determined at 2.15 A resolution. The structure suggests possible gene duplication within each subunit of the dimer (residues 35-119 and 130-199) and reveals an interesting proline-rich region on the protein surface (residues 119-130), which might act as a recognition site for protein-protein interactions. The structure also offers an explanation for its regulation by small ligands, such as tryptophan, a feature previously unknown in the prototypical Escherichia coli chorismate mutase. The tryptophan ligand is found to be sandwiched between the two monomers in a dimer contacting residues 66-68. The active site in the "gene-duplicated" monomer is occupied by a sulfate ion and is located in the first half of the polypeptide, unlike in the Saccharomyces cerevisiae (yeast) enzyme, where it is located in the later half. We hypothesize that the M. tuberculosis chorismate mutase might have a role to play in host-pathogen interactions, making it an important target for designing inhibitor molecules against the deadly pathogen.     

Evaluation of a fiberoptic-based system for measurement of optical properties in highly attenuating turbid media

Background  

Accurate measurements of the optical properties of biological tissue in the ultraviolet A and short visible wavelengths are needed to achieve a quantitative understanding of novel optical diagnostic devices. Currently, there is minimal information on optical property measurement approaches that are appropriate for in vivo measurements in highly absorbing and scattering tissues. We describe a novel fiberoptic-based reflectance system for measurement of optical properties in highly attenuating turbid media and provide an extensive in vitro evaluation of its accuracy. The influence of collecting reflectance at the illumination fiber on estimation accuracy is also investigated.