Residues located in the primase domain of the bacteriophage T7 primase-helicase are essential for loading the hexameric complex onto DNA.

The T7 primase-helicase plays a pivotal role in the replication of T7 DNA. Using affinity isolation of peptide-nucleic acid crosslinks and mass spectrometry, we identify protein regions in the primase-helicase and T7 DNA polymerase that form contacts with the RNA primer and DNA template. The contacts between nucleic acids and the primase domain of the primase-helicase are centered in the RNA polymerase subdomain of the primase domain, in a cleft between the N-terminal subdomain and the topoisomerase-primase fold. We demonstrate that residues along a beta sheet in the N-terminal subdomain that contacts the RNA primer are essential for phage growth and primase activity in vitro. Surprisingly, we found mutations in the primase domain that had a dramatic effect on the helicase. Substitution of a residue conserved in other DnaG-like enzymes, R84A, abrogates both primase and helicase enzymatic activities of the T7 primase-helicase. Alterations in this residue also decrease binding of the primase-helicase to ssDNA. However, mass photometry measurements show that these mutations do not interfere with the ability of the protein to form the active hexamer.

Men's comfort in distributing or receiving HIV self-test kits from close male social network members in Dar Es Salaam, Tanzania: baseline results from the STEP project.

BACKGROUND: A variety of strategies have been used to reach men with HIV self-testing services, including social network-based HIV self-test kits distribution. However, few studies have assessed men's comfort to distribute to or receive HIV self-test kits from close male friends within the same social network. In this study, we assessed men's comfort to distribute to and/or receive HIV self-test kits from close male friends and associated factors among men who socialize in networks locally referred to as "camps" in Tanzania. METHODS: Data are from the baseline survey of a cluster-randomized controlled trial conducted in June 2019 with 18 social networks or "camps" in Dar es Salaam, Tanzania. Participants were 18-year-old or older male camp members who were HIV-negative at the time of enrolment. We used the Generalized Estimating Equations (GEE) to assess factors associated with being comfortable to distribute to and/or receive HIV self-test kits from close male members within one's social network. RESULTS: Of 505 participants, 67.9% (n = 342) reported being comfortable to distribute to while 68.2% (n = 344) were comfortable to receive HIV self-test kits from their close male friends. Ever having heard about HIV self-testing (Adjusted Prevalence Ratio (Adj. PR): 1.6; 95% Confidence Interval [CI]: 1.3, 1.9), willingness to self-test for HIV in front of a sexual partner (Adj. PR: 3.0; 95%CI: 1.5, 6.1) and exposure to peer-led HIV self-testing education and promotion (Adj. PR: 1.4; 95%CI: 1.2, 1.7) were significantly associated with being comfortable to distribute HIV self-test kits to close male members within one's social network. Similar results were observed for being comfortable to receive HIV self-test kits from a close male friend within one's social network. CONCLUSIONS: Overall, these findings suggest that distribution of HIV self-test kits through close male friends could improve the proportion of men reached with HIV self-testing services and improve HIV testing rates in this population where uptake remains low. However, additional promotional strategies such as peer-led HIV self-testing education are needed to raise awareness and increase the proportion of men who are comfortable to receive and/or distribute HIV self-testing kits.

Persister-mediated emergence of antimicrobial resistance in agriculture due to antibiotic growth promoters.

The creation and continued development of antibiotics have revolutionized human health and disease for the past century. The emergence of antimicrobial resistance represents a major threat to human health, and practices that contribute to the development of this threat need to be addressed. Since the 1950s, antibiotics have been used in low doses to increase growth and decrease the feed requirement of animal-derived food sources. A consequence of this practice is the accelerated emergence of antimicrobial resistance that can influence human health through its distribution via animal food products. In the laboratory setting, sublethal doses of antibiotics promote the expansion of bacterial persister populations, a low energy, low metabolism phenotype characterized broadly by antibiotic tolerance. Furthermore, the induction of persister bacteria has been positively correlated with an increased emergence of antibiotic-resistant strains. This body of evidence suggests that the use of antibiotics in agriculture at subtherapeutic levels is actively catalyzing the emergence of antimicrobial-resistant bacteria through the expansion of bacterial persister populations, which is potentially leading to increased infections in humans and decreased antibiotic potency. There is an urgent need to address this debilitating effect on antibiotics and its influence on human health. In this review, we summarize the recent literature on the topic of emerging antimicrobial resistance and its association with bacterial persister populations.

HIV Self-Testing Uptake and Intervention Strategies Among Men in Sub-Saharan Africa: A Systematic Review.

Background: HIV testing is an essential gateway to HIV prevention and treatment services. However, HIV testing uptake remains low among men due to stigma, discrimination, and confidentiality concerns. HIV self-testing (HIVST) is an alternative HIV testing method that can address many of these barriers for men. We conducted a systematic review to examine HIVST uptake and intervention strategies among Men in Sub-Saharan Africa. Methods: We used a systematic approach to survey literature published from January 2010 to June 2020 using five electronic databases (PubMed-Medline, CINAHL Complete, PsychINFO, Google Scholar, and Web of Science) and a manual search. Studies were included if they were peer-reviewed, published in English, and examined HIVST willingness, uptake, and/or linkage to care and included men in Sub-Saharan Africa. Results: Sixty-three articles related to HIVST were reviewed. Of the included articles, 37 discussed HIVST uptake/acceptability and 24 discussed intervention strategies. Both oral swab and finger-prick methods had high acceptability with ease of access and availability of the test cited as important by men. Free HIVST kits were preferred by men. Secondary distribution of kits via peers, sexual partners, and female sex workers were successful. Conclusion: HIV self-testing is highly acceptable to men. More efforts are needed to develop policies to implement HIVST programs targeting men in Sub-Saharan Africa, including a focus on linkage to care in sub-Saharan Africa. Future interventions should directly target men independently in tandem with using peers and their romantic partners to promote self-testing among men in sub-Saharan Africa. HIVST kit distribution strategies should be combined with services that can offer confirmatory tests and counseling for men as well as linkage to care.

Microfinance and Peer Health Leadership Intervention Implementation for Men in Dar es Salaam, Tanzania: A Qualitative Assessment of Perceived Economic and Health Outcomes.

Men in sub-Saharan Africa continue to experience health disparities that are exacerbated by low employment. This study qualitatively assessed men's perceptions of the economic and health-care-seeking effects of participation in an integrated microfinance and peer health leadership intervention on violence and HIV risk reduction in Tanzania. Three focus group discussions with 27 men, aged 20 to 44 years, examined the perceived effects on income generation, employability, mental health, and uptake of HIV and related health services. All discussions were recorded, transcribed, and analyzed using deductive and inductive coding methods. Men reported that the benefits of the intervention included increased employability and income-earning activities due to greater access to entrepreneurial training, low-interest microfinancing, and male-oriented group supports to start or strengthen their businesses. Increased wages through business or other forms of employment were also attributed to men's lower anxiety and distress as financial providers for their families. However, men indicated that apart from the uptake of free HIV testing services, there was limited change in overall health-care-seeking behavior given the high clinic fees and lost time to earn income when attending routine health visits. Men recommended that future microfinance and health promotion interventions provide larger loan amounts, less frequent repayment intervals, and access to health and social insurance. Microfinance and peer health leadership interventions may help to address economic and health disparities in poor, urban men. Efforts are needed to assist lower income men in accessing financial tools as well as fee-based preventive and health-care services.