Impact of vaginal microbiome communities on HIV antiretroviral-based pre-exposure prophylaxis (PrEP) drug metabolism

Despite the efficacy of antiretroviral-based pre-exposure prophylactics (PrEP) in men who have sex with men, studies in women have produced widely varying outcomes. Recent evidence demonstrates that vaginal microbial communities are associated with increased HIV acquisition risk and may impact PrEP efficacy. Here, we investigate the mechanisms underlying how vaginal bacteria alter PrEP drug levels and impact HIV infection rates ex vivo. Using cervicovaginal lavages (CVLs) from women with or without bacterial vaginosis (BV), we identified microbial metabolism of PrEP drugs in BV samples through LC-MS/MS analysis of soluble drug levels and metabolite formation in dual T-cell cultures. CVL samples were assessed for microbiome analysis using sequencing of bacterial 16S rRNA genes. We also observed non-Lactobacillus bacteria that are associated with BV may potentially impact PrEP efficacy through increased HIV infection rates in co-cultures containing Lactobacillus or BV bacteria, PrEP drugs, CEM-GFP cells, and HIV-1_LAI virus. Finally, we used these data to develop a novel predictive mathematical simulation modeling system to predict these drug interactions for future trials. These studies demonstrate how dysbiotic vaginal microbiota may impact PrEP drugs and provides evidence linking vaginal bacteria to PrEP efficacy in women.     

Stimulation of extracellular protein production in Bacillus brevis 47

Summary Bacillus brevis 47 was cultivated in 2-1 fermentors to study the effect of medium supplementation on extracellular protein production. Additional polypeptone, when supplied initially or at 12 h (late exponential phase), had little stimulatory effect on extracellular protein levels, which reached 6–7 g/l after 48h. A large increase in protein production was observed, however, when polypeptone was added at 21 h (stationary phase). This addition resulted in the accumulation in the medium of 14 g/l protein after 48 h, and a total of 16 g/l when cell-bound protein was included. In all cases, glucose was consumed only very slowly.     

Assessment of methods to determine minimal cellulase concentrations for efficient hydrolysis of cellulose

Summary The enzyme loading needed to achieve substrate saturation appeared to be the most economical enzyme concentration to use for hydrolysis, based on percentage hydrolysis. Saturation was reached at 25 filter paper units per gram substrate on Solka Floc BW300, as determined by studying (a) initial adsorption of the cellulase preparation onto the substrate, (b) an actual hydrolysis or (c) a combined hydrolysis and fermentation (CHF) process. Initial adsorption of the cellulases onto the substrate can be used to determine the minimal cellulase requirements for efficient hydrolysis since enzymes initially adsorbed to the substrate have a strong role in governing the overall reaction. Trichoderma harzianum E58 produces high levels of -glucosidase and is able to cause high conversion of Solka Floc BW300 to glucose without the need for exogenous -glucosidase. End-product inhibition of the cellulase and -glucosidase can be more effectively reduced by employing a CHF process than by supplemental -glucosidase.Offprint requests to: C. M. Hogan     

In vitro plantlet regeneration from cotyledon, hypocotyl and root explants of hybrid seed geranium

In vitro plantlet regeneration systems for the seed geranium (Pelargonium x hortorum Bailey) using cotyledon, hypocotyl and root explants were optimized by studying the influence of seedling age, growth regulators and excision orientation on organogenesis. Indole-3-acetic acid combined with zeatin yielded the highest rate of shoot production on cotyledon explants (0.2–2 shoots per explant). More shoots were produced on explants cut from the most basal region of cotyledons from 2 to 4-day-old seedlings than from older seedlings or more distal cut sites. Hypocotyl explants produced the highest number of shoots, up to 40 shoots per explant, on indole-3-acetic acid (2.8–5.6 mM) + zeatin (4.6 mM) or thidiazuron (4.5 mM). Maximum shoot formation (0.3–1.4 shoots per explant) on root explants occurred when they were cultured on medium containing zeatin. Regenerated shoots rooted best on a basal medium containing no growth regulators. There were substantial differences among cultivars in shoot formation from each of the explant systems.Abbreviations BA 6-benzylaminopurine - 2,4-d 2,4-dichlorophenoxyacetic acid - IAA indole-3-acetic acid - NAA naphthaleneacetic acid - TDZ thidiazuron     

Environmental,geographical and time-related impacts on avian malaria infections in native and introduced populations of house sparrows (Passer domesticus), a globally invasive species

Aim

The increasing spread of vector-borne diseases has resulted in severe health concerns for humans, domestic animals and wildlife, with changes in land use and the introduction of invasive species being among the main possible causes for this increase. We explored several ecological drivers potentially affecting the local prevalence and richness of avian malaria parasite lineages in native and introduced house sparrows (Passer domesticus) populations.

Location

Global.

Time period

2002–2019.

Major taxa studied

Avian Plasmodium parasites in house sparrows.

Methods

We analysed data from 2,220 samples from 69 localities across all continents, except Antarctica. The influence of environment (urbanization index and human density), geography (altitude, latitude, hemisphere) and time (bird breeding season and years since introduction) were analysed using generalized additive mixed models (GAMMs) and random forests.

Results

Overall, 670 sparrows (30.2%) were infected with 22 Plasmodium lineages. In native populations, parasite prevalence was positively related to urbanization index, with the highest prevalence values in areas with intermediate urbanization levels. Likewise, in introduced populations, prevalence was positively associated with urbanization index; however, higher infection occurred in areas with either extreme high or low levels of urbanization. In introduced populations, the number of parasite lineages increased with altitude and with the years elapsed since the establishment of sparrows in a new locality. Here, after a decline in the number of parasite lineages in the first 30 years, an increase from 40 years onwards was detected.

Main conclusions

Urbanization was related to parasite prevalence in both native and introduced bird populations. In invaded areas, altitude and time since bird introduction were related to the number of Plasmodium lineages found to be infecting sparrows.     

Optical measurement of isolated canine lung filtration coefficients at normal hematocrits

Klaesner, Joseph W., N. Adrienne Pou, Richard E. Parker,Charlene Finney, and Robert J. Roselli. Optical measurement ofisolated canine lung filtration coefficients at normal hematocrits. J. Appl. Physiol. 83(6):1976-1985, 1997.In this study, lung filtration coefficient(K_fc) valueswere measured in eight isolated canine lung preparations at normalhematocrit values using three methods: gravimetric, blood-correctedgravimetric, and optical. The lungs were kept in zone 3 conditions andsubjected to an average venous pressure increase of 10.24 ± 0.27 (SE) cmH₂O. The resulting K_fc(ml · min¹ · cmH₂O¹ · 100 g dry lung wt¹) measuredwith the gravimetric technique was 0.420 ± 0.017, which wasstatistically different from theK_fc measured bythe blood-corrected gravimetric method (0.273 ± 0.018) or theproduct of the reflection coefficient(_f) andK_fc measuredoptically (0.272 ± 0.018). The optical method involved the use of aCellco filter cartridge to separate red blood cells from plasma, whichallowed measurement of the concentration of the tracer in plasma atnormal hematocrits (34 ± 1.5). The permeability-surface areaproduct was measured using radioactive multiple indicator-dilutionmethods before, during, and after venous pressure elevations. Resultsshowed that the surface area of the lung did not change significantlyduring the measurement ofK_fc. Thesestudies suggest that_fK_fccan be measured optically at normal hematocrits, that this measurement is not influenced by blood volume changes that occur during the measurement, and that the optical_fK_fcagrees with theK_fc obtained viathe blood-corrected gravimetric method.

     

Distribution of Na+, K+-ATPase α-Subunit Isoforms in Rat Pituitary

The distributions of alpha-subunit isoforms of the Na+,K(+)-ATPase in rat pituitary were determined by immunoblotting and immunohistochemistry. Immunoreactivity for all three forms is present in the neural lobe, whereas the anterior lobe contains only alpha 1 and alpha 2. Most areas of the intermediate lobe exhibit faint immunoreactivity for only alpha 1, but thin strands of cells which stain strongly for all three isoforms are also present in this lobe. The previously reported ouabain inhibitable Na+,K(+)-ATPase activity in the neural lobe is consistent with the presence of both alpha 2 and alpha 3 subunits.     

Attack of the PCR clones: Rates of clonality have little effect on RAD‐seq genotype calls

Interpretation of high‐throughput sequence data requires an understanding of how decisions made during bioinformatic data processing can influence results. One source of bias that is often cited is PCR clones (or PCR duplicates). PCR clones are common in restriction site‐associated sequencing (RAD‐seq) data sets, which are increasingly being used for molecular ecology. To determine the influence PCR clones and the bioinformatic handling of clones have on genotyping, we evaluate four RAD‐seq data sets. Data sets were compared before and after clones were removed to estimate the number of clones present in RAD‐seq data, quantify how often the presence of clones in a data set causes genotype calls to change compared to when clones were removed, investigate the mechanisms that lead to genotype call changes and test whether clones bias heterozygosity estimates. Our RAD‐seq data sets contained 30%–60% PCR clones, but 95% of RAD‐tags had five or fewer clones. Relatively few genotypes changed once clones were removed (5%–10%), and the vast majority of these changes (98%) were associated with genotypes switching from a called to no‐call state or vice versa. PCR clones had a larger influence on genotype calls in individuals with low read depth but appeared to influence genotype calls at all loci similarly. Removal of PCR clones reduced the number of called genotypes by 2% but had almost no influence on estimates of heterozygosity. As such, while steps should be taken to limit PCR clones during library preparation, PCR clones are likely not a substantial source of bias for most RAD‐seq studies.     

Palladium Catalysis in the Synthesis of 8-Position modified Adenosine, 2′-Deoxyadenosine and Guanosine

Abstract

Adenosine and guanosine analogs with 8-position vinyl and aryl groups were prepared by palladium catalyzed cross-coupling of organostannanes with 8-bromopurine nucleosides. The reaction conditions and catalyst composition were improved so that both vinyl and aryl modifications could be made by a general procedure.