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41.
Saidi H. Kapiga Fiona M. Ewings Tony Ao Joseph Chilongani Aika Mongi Kathy Baisley Suzanna Francis Aura Andreasen Ramadhan Hashim Deborah Watson-Jones John Changalucha Richard Hayes 《PloS one》2013,8(7)
Objectives
To prepare for future HIV prevention trials, we conducted prospective cohort studies among women working in food and recreational facilities in northern Tanzania. We examined the prevalence and incidence of HIV and HSV-2, and associated risk factors.Methods
Women aged 18–44 years working in food and recreational facilities were screened to determine their eligibility for the studies. Between 2008–2010, HIV-negative women were enrolled and followed for 12 months. At enrolment and 3-monthly, we collected socio-demographic and behavioural data, and performed clinical examinations for collection of biological specimens that were tested for reproductive tract infections. Risk factors for HIV and HSV-2 incidence were investigated using Poisson regression models.Results
We screened 2,229 and enrolled 1,378 women. The median age was 27 years (interquartile range, IQR 22, 33), and median duration working at current facility was 2 years. The prevalences of HIV at screening and HSV-2 at enrolment were 16% and 67%, respectively. Attendance at the 12-month visit was 86%. HIV and HSV-2 incidence rates were 3.7 (95% confidence interval, CI: 2.8,5.1) and 28.6 (95% CI: 23.5,35.0)/100 person-years, respectively. Women who were separated, divorced, or widowed were at increased risk of HIV (adjusted incidence rate ratio, aRR = 6.63; 95% CI: 1.97,22.2) and HSV-2 (aRR = 2.00; 95% CI: 1.15,3.47) compared with married women. Women reporting ≥3 partners in the past 3 months were at higher HIV risk compared with women with 0–1 partner (aRR = 4.75; 95% CI: 2.10,10.8), while those who had reached secondary education or above were at lower risk of HSV-2 compared with women with incomplete primary education (aRR = 0.42; 95% CI: 0.22,0.82).Conclusions
HIV and HSV-2 rates remain substantially higher in this cohort than in the general population, indicating urgent need for effective interventions. These studies demonstrate the feasibility of conducting trials to test new interventions in this highly-mobile population. 相似文献42.
43.
Sujatha Srinivasan Martin T. Morgan Congzhou Liu Frederick A. Matsen Noah G. Hoffman Tina L. Fiedler Kathy J. Agnew Jeanne M. Marrazzo David N. Fredricks 《PloS one》2013,8(10)
Bacterial vaginosis (BV) is a highly prevalent condition associated with adverse health outcomes. Gram stain analysis of vaginal fluid is the standard for confirming the diagnosis of BV, wherein abundances of key bacterial morphotypes are assessed. These Lactobacillus, Gardnerella, Bacteroides, and Mobiluncus morphotypes were originally linked to particular bacterial species through cultivation studies, but no studies have systematically investigated associations between uncultivated bacteria detected by molecular methods and Gram stain findings. In this study, 16S-rRNA PCR/pyrosequencing was used to examine associations between vaginal bacteria and bacterial morphotypes in 220 women with and without BV. Species-specific quantitative PCR (qPCR) and fluorescence in Situ hybridization (FISH) methods were used to document concentrations of two bacteria with curved rod morphologies: Mobiluncus and the fastidious BV-associated bacterium-1 (BVAB1). Rank abundance of vaginal bacteria in samples with evidence of curved gram-negative rods showed that BVAB1 was dominant (26.1%), while Mobiluncus was rare (0.2% of sequence reads). BVAB1 sequence reads were associated with Mobiluncus morphotypes (p<0.001). Among women with curved rods, mean concentration of BVAB1 DNA was 2 log units greater than Mobiluncus (p<0.001) using species-specific quantitative PCR. FISH analyses revealed that mean number of BVAB1 cells was 2 log units greater than Mobiluncus cells in women with highest Nugent score (p<0.001). Prevotella and Porphyromonas spp. were significantly associated with the “Bacteroides morphotype,” whereas Bacteroides species were rare. Gram-negative rods designated Mobiluncus morphotypes on Gram stain are more likely BVAB1. These findings provide a clearer picture of the bacteria associated with morphotypes on vaginal Gram stain. 相似文献
44.
Vertical farming using light-emitting diode offers potential for the early production phase (few weeks) of young ornamental plants. However, once transferred to the greenhouse, the photosynthetic acclimation of these young plants might depend on this initial light regime. To obtain insight about this acclimatization, Chrysanthemum (sun species) and Spathiphyllum (shade species) were preconditioned in growth chambers for 4 weeks under four light qualities: blue (B), red (R), red/blue (RB, 60% R) and white (W) at 100 μmol m−2 s−1. Monochromatic light (R and B) limited leaf development of both species, which resulted in a lower leaf mass per area when compared to multispectral light (RB for Chrysanthemum, RB and W for Spathiphyllum). R-developed leaves had a lower photosynthetic efficiency in both species. After the light quality pretreatment, plants were transferred to the greenhouse with high-intensity natural light conditions. On the first day of transfer, R and B preconditioned leaves of both species had an inhibited photosynthesis. After 1 week in natural light condition, rapid light curve parameters of Chrysanthemum leaves that developed under B acclimated to sunlight had a similar level than RB-developed leaves unlike R-leaves. Spathiphyllum leaves showed a decrease in maximum electron transport rate and this was most pronounced for the R pretreatment. After 1 month, R-preconditioned Chrysanthemum had the lowest dry mass, while no effects on the dry weight of Spathiphyllum with respect to the pretreatments were observed. Light quality during preconditioning affected the leaf ability to acclimate to natural high light intensities in greenhouse environment. 相似文献
45.
Kelsey J. R. P. Byers Kathy Darragh Jamie Musgrove Diana Abondano Almeida Sylvia Fernanda Garza Ian A. Warren Pasi M. Rastas Marek Kučka Yingguang Frank Chan Richard M. Merrill Stefan Schulz W. Owen McMillan Chris D. Jiggins 《Evolution; international journal of organic evolution》2020,74(2):349-364
Understanding the production, response, and genetics of signals used in mate choice can inform our understanding of the evolution of both intraspecific mate choice and reproductive isolation. Sex pheromones are important for courtship and mate choice in many insects, but we know relatively little of their role in butterflies. The butterfly Heliconius melpomene uses a complex blend of wing androconial compounds during courtship. Electroantennography in H. melpomene and its close relative Heliconius cydno showed that responses to androconial extracts were not species specific. Females of both species responded equally strongly to extracts of both species, suggesting conservation of peripheral nervous system elements across the two species. Individual blend components provoked little to no response, with the exception of octadecanal, a major component of the H. melpomene blend. Supplementing octadecanal on the wings of octadecanal-rich H. melpomene males led to an increase in the time until mating, demonstrating the bioactivity of octadecanal in Heliconius. Using quantitative trait locus (QTL) mapping, we identified a single locus on chromosome 20 responsible for 41% of the parental species’ difference in octadecanal production. This QTL does not overlap with any of the major wing color or mate choice loci, nor does it overlap with known regions of elevated or reduced FST. A set of 16 candidate fatty acid biosynthesis genes lies underneath the QTL. Pheromones in Heliconius carry information relevant for mate choice and are under simple genetic control, suggesting they could be important during speciation. 相似文献
46.
Kathy R. Chaurasiya Clarissa Ruslie Michelle C. Silva Lukas Voortman Philip Nevin Samer Lone Penny J. Beuning Mark C. Williams 《Nucleic acids research》2013,41(19):8959-8968
Replication by Escherichia coli DNA polymerase III is disrupted on encountering DNA damage. Consequently, specialized Y-family DNA polymerases are used to bypass DNA damage. The protein UmuD is extensively involved in modulating cellular responses to DNA damage and may play a role in DNA polymerase exchange for damage tolerance. In the absence of DNA, UmuD interacts with the α subunit of DNA polymerase III at two distinct binding sites, one of which is adjacent to the single-stranded DNA-binding site of α. Here, we use single molecule DNA stretching experiments to demonstrate that UmuD specifically inhibits binding of α to ssDNA. We predict using molecular modeling that UmuD residues D91 and G92 are involved in this interaction and demonstrate that mutation of these residues disrupts the interaction. Our results suggest that competition between UmuD and ssDNA for α binding is a new mechanism for polymerase exchange. 相似文献
47.
James V. Lee Edward L. Maclin Kathy A. Low Gabriele Gratton Monica Fabiani David F. Clayton 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2013,199(3):227-238
Songbirds communicate by learned vocalizations with concomitant changes in neurophysiological and genomic activities in discrete parts of the brain. Here, we tested a novel implementation of diffusive optical imaging (also known as diffuse optical imaging, DOI) for monitoring brain physiology associated with vocal signal perception. DOI noninvasively measures brain activity using red and near-infrared light delivered through optic fibers (optodes) resting on the scalp. DOI does not harm subjects, so it raises the possibility of repeatedly measuring brain activity and the effects of accumulated experience in the same subject over an entire life span, all while leaving tissue intact for further study. We developed a custom-made apparatus for interfacing optodes to the zebra finch (Taeniopygia guttata) head using 3D modeling software and rapid prototyping technology, and applied it to record responses to presentations of birdsong in isoflurane-anesthetized zebra finches. We discovered a subtle but significant difference between the hemoglobin spectra of zebra finches and mammals which has a major impact in how hemodynamic responses are interpreted in the zebra finch. Our measured responses to birdsong playback were robust, highly repeatable, and readily observed in single trials. Responses were complex in shape and closely paralleled responses described in mammals. They were localized to the caudal medial portion of the brain, consistent with response localization from prior gene expression, electrophysiological, and functional magnetic resonance imaging studies. These results define an approach for collecting neurophysiological data from songbirds that should be applicable to diverse species and adaptable for studies in awake behaving animals. 相似文献
48.
Aims
Because the water status of grapevines strongly affects the quality of the grapes and resulting wine, automated and early drought stress detection is important. Plant measurements are very promising for detecting drought stress, but strongly depend on microclimatic changes. Therefore, conventional stress detection methods require threshold values which define when plants start sensing drought stress. There is however no unique method to define these values. In this study, we propose two techniques that overcome this limitation.Methods
Two statistical methods were used to automatically distinguish between drought and microclimate effects, based on a short preceding full-irrigated period to extract plant behaviour under normal conditions: Unfold Principal Component Analysis (UPCA) and Functional Unfold Principal Component Analysis (FUPCA). Both techniques aimed at detecting when measured sap flow rate or stem diameter variations in grapevine deviated from their normal behaviour due to drought stress.Results
The models based on sap flow rate had some difficulties to detect stress on days with low atmospheric demands, while those based on stem diameter variations did not show this limitation, but ceased detecting stress when the stem diameter levelled off after a period of severe shrinkage. Nevertheless, stress was successfully detected with both approaches days before visible symptoms appeared.Conclusions
UPCA and FUPCA based on plant indicators are therefore very promising for early stress detection. 相似文献49.
50.
Ian S. Pearse Kathy Hughes Kaori Shiojiri Satomi Ishizaki Richard Karban 《Oecologia》2013,172(3):869-875
The importance of interplant volatile signaling in plant–herbivore interactions has been a contentious issue for the past 30 years. We revisit willows as the system in which evidence for interplant signaling was originally found, but then questioned. We established three well-replicated experiments with two willow species (Salix exigua and Salix lemmonii) to address whether the receipt of an interplant signal from a neighboring willow reduces herbivore damage. Additionally we tested whether this signal is volatile in nature, and whether plants signal better to themselves than they do to other individuals. In all three experiments, we found evidence that cues from a damaged neighbor reduce subsequent herbivory experienced by willows. In one experiment, we showed that bagging of clipped tissue, which prevents the exchange of volatile signals, removed the effect of neighbor wounding. This was consistent with results from the other two experiments, in which clipping potted neighbors connected only through airborne volatile cues reduced damage of receivers. In one year, we found evidence that the perception of volatile signals from genetically identical clones was more effective at reducing foliar damage to a neighbor than signals from a genetically different individual. However, this trend was not significant in the following year. In three well-replicated experiments, we found strong evidence for the importance of interplant volatile cues in mediating herbivore interactions with willows. 相似文献