No abstract

Young women in sub-Saharan Africa are disproportionally affected by HIV infection and unintended pregnancies. However, hormonal contraceptive (HC) use may influence HIV risk through changes in genital tract microbiota and inflammatory cytokines. To investigate this, 130 HIV negative adolescent females aged 15–19 years were enrolled into a substudy of UChoose, an open-label randomized crossover study (NCT02404038), comparing acceptability and contraceptive product preference as a proxy for HIV prevention delivery methods. Participants were randomized to injectable norethisterone enanthate (Net-En), combined oral contraceptives (COC) or etonorgesterol/ethinyl estradiol combined contraceptive vaginal ring (CCVR) for 16 weeks, then crossed over to another HC for 16 weeks. Cervicovaginal samples were collected at baseline, crossover and exit for characterization of the microbiota and measurement of cytokine levels; primary endpoints were cervical T cell activation, vaginal microbial diversity and cytokine concentrations. Adolescents randomized to COCs had lower vaginal microbial diversity and relative abundance of HIV risk-associated taxa compared to Net-En or CCVR. Cervicovaginal inflammatory cytokine concentrations were significantly higher in adolescents randomized to CCVR compared to COC and Net-En. This suggests that COC use may induce an optimal vaginal ecosystem by decreasing bacterial diversity and inflammatory taxa, while CCVR use is associated with genital inflammation.

13 14 Running title: Decomposition gene expression in the rhizosphere 15 16 Corresponding authors: Erin Nuccio nuccio1@llnl.gov 925-423-9983, Jennifer Pett-Ridge 17 pettridge2@llnl.gov 925-424-2882, Lawrence Abstract 20 The rhizosphere is a hotspot for microbial C transformations, and the origin of root polysaccharides and 21 polymeric carbohydrates that are important precursors to soil organic matter. However, the ecological 22 109 110 Sample Collection 111 Rhizosphere soil <2 mm from the root was excised with a scalpel. Root sections and adhering soil were 112 placed immediately in ice cold Lifeguard Soil Preservation Reagent (MoBio), vortexed for 2 min on 113 medium speed, and pelleted according to the Lifeguard protocol. Roots were removed using flame-114

A biofilm sample was collected from an anaerobic water and gasflowing borehole, 1.474 km below land surface in the Evander Au mine, Republic of South Africa. The biofilm was 27 wt% ZnS, which was ∼2 × 10 7 times more concentrated than the dissolved Zn measured in the borehole water. X-Ray diffraction indicated that the Zn was present in the form of fine grained, 4.7 ± 0.9 nm particles with smaller amounts of pyrite (FeS 2 ). Scanning electron microscopy, coupled with energy-dispersive X-ray spectroscopy confirmed the identity of these minerals in the biofilm. Using transmission electron microscopy, the fine-grained ZnS minerals were found to coat the 1 μm-diameter rod-shaped bacteria that made up the primary substructure of the biofilm. The FeS 2 was present as framboids (spherical aggregates of 0.5-1 μm FeS 2 crystals) up to 10 μm in diameter and as large, 2-3 μm euhedral crystals that were not nucleated on the bacterial surfaces, but were found within the biofilm. Analyses of 16S rDNA utilizing clone libraries and a phylochip indicates that the ZnS rich biofilm is dominated by methanogens with a significant sulfate-reducing bacterial population and minor sulfide and CH 4 -oxidizing chemolithotrophs. This biofilm community is sustained by sulfate, bicarbonate and H 2 -bearing paleometeoric water.