Small acid-soluble spore proteins (SASPs) appear 3-4 hr after the onset of sporulation in Gram-positive bacteria and constitute up to 20% of the protein of mature spores. Previous studies using Bacillus subtlis deletion mutants lacking SASP-a and -1S have shown that such mutations abolish the elevated resistance ofspores to UV radiation. Analyses using circular dichroism and Fourier-transform infrared spectroscopy now demonstrate that bining a/f-type SASPs to DNA in vitro causes a structural change in DNA, from the B to the A conformation. This may provide the basis whereby a/f8-type SASPs confer increased spore UV resistance in vivo-by changing spore DNA conformation, they alter DNA photochemistry such that UV irradiation produces spore photoproduct instead of the more lethal cyclobutane-type thymine dimers.genes (termed ssp genes) exhibit a remarkably high degree of conservation of their primary sequences throughout evolution (10), and any one ofthe a/a-type SASPs appears capable ofconferring UV resistance on bacterial spores (11). By using several purified a/,a-type SASPs, we have examined the effects of SASP on DNA conformation, and we report here that SASP binding to DNA in vitro induces a B -> A conformation change. It seems likely that this phenomenon underlies the ability of SASP to protect spore DNA against thymine-dimer formation. Given their evolutionary antiquity (10), the SASPs also may have as-yet-undiscovered protein relatives that use the same strategy to protect cells against UV. The high intrinsic UV resistance of obligate anaerobic bacteria (12), for example, may reflect just such a system. Among the dramatic changes accompanying sporulation in Gram-positive bacteria, a major increase in resistance to killing by UV radiation ranks high as a factor ensuring that the organism will survive dormancy (1). Detailed study of this phenomenon has shown that UV irradiation of spores produces no detectable cis-syn cyclobutane-type thymine dimers in DNA-in sharp contrast with the predominance of this lesion in other UV-irradiated in vivo systems. Instead, the DNA of UV-irradiated spores accumulates primarily 5-thyminyl-5,6-dihydrothymine ("spore photoproduct") (2,3). Germinating spores contain a specific enzyme that efficiently repairs spore photoproduct (4), thereby ensuring a high probability of survival after exposure to UV.It is clear that DNA conformation can significantly alter photoreactivity (5) and the type of UV-induced photoproducts (6). Thus, one simple explanation for the change in DNA photochemistry that occurs during sporulation invokes an alteration in DNA conformation. Indeed, to explain the altered photochemistry of spore DNA, it was suggested a number of years ago that DNA in bacterial spores is in the A conformation whose stereochemical constraints inhibit thymine dimer formation (7). Howe-, er, the relationship between A-DNA and UV-induced formation of spore photoproduct has never been proven, and it has been suggested (6, 8) that hydration is a more important determinant of D...

We evaluated the efficacy of a peer-educator network intervention as a strategy to reduce HIV acquisition among injection drug users (IDUs) and their drug and/or sexual networks. A randomized controlled trial was conducted in St. Petersburg, Russia among IDU index participants and their risk network participants. Network units were randomized to the control or experimental intervention. Only the experimental index participants received training sessions to communicate risk reduction techniques to their network members. Analysis includes 76 index and 84 network participants who were HIV uninfected. The main outcome measure was HIV sero-conversion. The incidence rates in the control and experimental groups were 19.57 (95 % CI 10.74–35.65) and 7.76 (95 % CI 3.51–17.19) cases per 100 p/y, respectively. The IRR was 0.41 (95 % CI 0.15–1.08) without a statistically significant difference between the two groups (log rank test statistic X2 = 2.73, permutation p value = 0.16). Retention rate was 67 % with a third of the loss due to incarceration or death. The results show a promising trend that this strategy would be successful in reducing the acquisition of HIV among IDUs.

In this study, we investigated how individual attributes, dyad characteristics and social network characteristics may influence engaging in receptive syringe sharing, distributive syringe sharing and sharing cookers in injecting partnerships of IDUs in St Petersburg, Russia. We found that all three levels were associated with injecting equipment sharing, and that dyad characteristics were modified by characteristics of the social network. Self-reported HIV discordance and male gender concordance played a role in the risk of equipment sharing. Dyad interventions may not be sufficient to reduce injecting risk in IDU partnerships, but a combination of dyad and network interventions that target both IDU partnerships and the entire IDU population may be more appropriate to address injecting risk among IDUs.

Aims: To assess among injecting drug users (IDUs) in St. Petersburg, Russia, the urban environment, social norms and individual correlates of unsafe injecting. Methods: Between December 2004 and January 2007, 446 IDUs were interviewed in St. Petersburg, Russia. Results: Prevalence of HCV was 96% and HIV 44%. 17% reported receptive syringe sharing after an HIV-infected IDU, 49% distributive syringe sharing, 76% sharing cookers, 73% sharing filters and 71% syringe-mediated drug sharing when not all syringes were new. Urban environmental characteristics correlated with sharing cookers and syringe-mediated sharing, and social norms correlated with receptive and distributive syringe sharing and sharing cookers. Individual correlates included cleaning used syringes (all 5 dependent variables) and self-report of HIV infection (receptive and distributive syringe sharing). Conclusion: HIV status disclosure is an unreliable but frequently used HIV prevention method among IDUs in St. Petersburg, who reported alarmingly high levels of injecting equipment sharing. Voluntary counseling and testing should be widely available for this population. Ethnography is needed to assess the effectiveness of the syringe cleaning process. Prevention interventions need to be ongoing among IDUs in St. Petersburg, and should incorporate urban environmental factors and social norms, which may involve peer education and social network interventions.