Context and dynamics of same-sex behavior among long-distance truckers in India: Findings from qualitative research

It is well established that truckers (drivers and helpers) have higher rates of nonmarital sex than any other occupational group. Because of this multipartner sexual activity, truckers form a key group of prevention efforts for HIV and sexually transmitted infections (STIs). Thus far, HIV/STI prevention interventions for truckers have been geared to providing risk-reduction information and services within a heterosexual context. Recent evidence suggests that a significant number of truckers engage in male-to-male (MSM) sexual activity that has implications for HIV/STI transmission. Therefore, information on the nature and extent of MSM activity among these populations is urgently needed for the design and implementation of comprehensive prevention programs. The Transport Corporation of India Foundation (TCIF) is implementing Project Kavach to reduce HIV/STI vulnerability among 1.5 million truckers and their partners. TCIF collaborated with the Population Council to undertake an exploratory study to understand the dynamics of same sexual behavior among truckers. As stated in this report, evidence from this research will guide TCIF in designing appropriate program strategy and activities to provide comprehensive HIV/STI prevention services to their key population of truckers

Integration Host Factor of <i>Mycobacterium tuberculosis</i>, mIHF, Compacts DNA by a Bending Mechanism

<div><p>The bacterial chromosomal DNA is folded into a compact structure called as ‘nucleoid’ so that the bacterial genome can be accommodated inside the cell. The shape and size of the nucleoid are determined by several factors including DNA supercoiling, macromolecular crowding and nucleoid associated proteins (NAPs). NAPs bind to different sites of the genome in sequence specific or non-sequence specific manner and play an important role in DNA compaction as well as regulation. Until recently, few NAPs have been discovered in mycobacteria owing to poor sequence similarities with other histone-like proteins of eubacteria. Several putative NAPs have now been identified in Mycobacteria on the basis of enriched basic residues or histone-like “PAKK” motifs. Here, we investigate mycobacterial Integration Host Factor (mIHF) for its architectural roles as a NAP using atomic force microscopy and DNA compaction experiments. We demonstrate that mIHF binds DNA in a non-sequence specific manner and compacts it by a DNA bending mechanism. AFM experiments also indicate a dual architectural role for mIHF in DNA compaction as well as relaxation. These results suggest a convergent evolution in the mechanism of <i>E. coli</i> and mycobacterial IHF in DNA compaction.</p></div

Role of mIHF-80 as a nucleoid associated protein.

<p>The role of mIHF-80 in DNA compaction was analyzed by (a) Ethidium bromide exclusion assay as well as (b) DNA protection assays. (a) Ethidium Bromide exclusion assay: A reaction mix containing plasmid DNA intercalated with Ethidium Bromide was incubated with 0 (no protein), 1, 4, 8, 16, or 20 µg mIHF-80 as indicated. The curve was normalized by taking the initial fluorescence reading (no protein) as 100%. The EtBr fluorescence decreases upto 40% upon DNA compaction with mIHF-80. A guideline indicating the decrease in fluorescence is also plotted. Rv2966c (8 µg) that binds DNA non-specifically <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0069985#pone.0069985-Kumar1" target="_blank">[47]</a> and BSA (10 µg) are used as controls, and show only marginal decrease in fluorescence. (b) DNA protection assay: mIHF-80 protects DNA from DNase digestion as increasing amount of mIHF-80 (lane 3: 7 µg, lane4: 35 µg, lane5: 70 µg, lane 6: 105 µg) is incubated with DNA. Negative (no DNase I) and positive controls (no mIHF-80) for the DNase activity are indicated in lanes 1 and 2, respectively.</p

EMSA for nucleic acid binding.

<p>Binding of mIHF-80 to (a) circular and (b) linear DNA was analyzed by running the reaction mixture on agarose gel and visualizing by EtBr staining. mIHF-80 binds DNA non-specifically in a concentration-dependent manner. (a) In the reaction mix, 18, 36, 75, 150, 300, 450, 600 or 900, (lanes 2–9) were incubated with circular supercoiled DNA at 37°C for 60 min. (b) To monitor binding to linear DNA, a similar reaction was carried out with 18, 37, 75, 150, 300, 450, 600 or 900 ng mIHF-80 (lanes 2–9) to monitor gel shift. Lane 1 is control with no protein in both gels.</p

Geometrical parameters of linear DNA+ mIHF-80 complexes.

a<p>Indicated values are averages of molecules analyzed (N).</p>b<p>σ is the Standard deviation for each parameter calculated over molecules analyzed (N).</p

CD profile of mIHF-80.

<p>A CD analysis of mIHF-80 is suggestive of a globular, folded protein. The protein appears to be primarily alpha-helical and the helical content calculated to be more than 85% of the total secondary structure content of the protein.</p

Representative AFM images of protein-DNA complexes formed between mIHF-80 and negatively supercoiled plasmid DNA.

<p>(A) Plasmid DNA in the absence of mIHF-80. (B)–(I): mIHF-80-pPROEX-HTc complexes with increasing mIHF-80 dimers per 10 base pair of DNA as follows; (B) 1, (C) 2, (D&E) 4, (F & G) 8. The scale of all images in A to G is (3 µm×3 µm). (H) & (I): Rigid nucleoprotein filaments identified in (F) and (G) above are shown at a slightly magnified scale of (1 µm×1 µm). The protein complexes are marked by arrows.</p

Representative AFM images of protein-DNA complexes formed between mIHF-80 and linear DNA.

<p>(A) Linear pPROEX-HTc in the absence of mIHF-80. (B)–(D): mIHF-80-pPROEX-HTc (linearized) complexes with following mIHF-80 dimer molecules per 10 base pairs of DNA; (B) 2, (C) 4 and (D) 8. The scale of all images is (3 µm×3 µm).</p