1,412 research outputs found
The Pathobiology of Neisseria gonorrhoeae Lower Female Genital Tract Infection
Infection and disease associated with Neisseria gonorrhoeae, the gonococcus, continue to be a global health problem. Asymptomatic and subclinical gonococcal infections occur at a high frequency in females; thus, the true incidence of N. gonorrhoeae infections are presumed to be severely underestimated. Inherent to this asymptomatic/subclinical diseased state is the continued prevalence of this organism within the general population, as well as the medical, economic, and social burden equated with the observed chronic, disease sequelae. As infections of the lower female genital tract (i.e., the uterine cervix) commonly result in subclinical disease, it follows that the pathobiology of cervical gonorrhea would differ from that observed for other sites of infection. In this regard, the potential responses to infection that are generated by the female reproductive tract mucosa are unique in that they are governed, in part, by cyclic fluctuations in steroid hormone levels. The lower female genital tract has the further distinction of being able to functionally discriminate between resident commensal microbiota and transient pathogens. The expression of functionally active complement receptor 3 by the lower, but not the upper, female genital tract mucosa; together with data indicating that gonococcal adherence to and invasion of primary cervical epithelial cells and tissue are predominately aided by this surface-expressed host molecule; provide one explanation for asymptomatic/subclinical gonococcal cervicitis. However, co-evolution of the gonococcus with its sole human host has endowed this organism with variable survival strategies that not only aid these bacteria in successfully evasion of immune detection and function but also enhance cervical colonization and cellular invasion. To this end, we herein summarize current knowledge pertaining to the pathobiology of gonococcal infection of the human cervix
The influences of dietary protein on bovine placental development and ovarian function
Dietary protein is a vital nutritional component in beef production due to its essential contribution to optimal reproductive efficiency, neonatal and post-pubertal growth rates. Cattle have had a declining fertility rate for several decades and previous literature has indicated a possible interaction with the high dietary protein levels. The two most critical structures influencing pregnancy are the ovary and placenta, therefore this study consisted of two experiments. Experiment 1 investigated the influence of changing dietary protein during the peri- and post-conception period on these structures. Experiment 2 investigated the effect of dietary protein in the non-pregnant beef heifer on a commercial farm setting. The hypothesis underpinning this study is that optimal dietary protein levels are required for maximal placental and ovarian function. To test this hypothesis two experiments were conducted.
In experiment 1, Australian nulliparous Bos indicus: Bos taurus cross heifers were fed isocaloric high (14%) or low (7%) crude protein diets (individually) from -60 days post-conception (dpc) to 23 dpc. Between 23dpc and 98dpc two groups then were fed either high or low crude protein diet which established four treatment groups. Treatments were assessed after the first trimester (98dpc) in order to investigate acute effects and at term in order to determine effects at parturition.
At 98dpc, 46 heifers were slaughtered and adult ovaries, placental tissue and fetal tissues were collected. The remaining 56 heifers were maintained on the same diet at recommended NRC recommended protein levels until calving. Immediately post-partum placentomes (3-5) were collected and characteristics of parturition (e.g. length, difficulty) recorded. Histological techniques were used to visualise the cellular composition of the placental structure and to determine the level of vascularisation within the placenta. Deep sequencing of the global gene expression of the placenta was determined using the Illumina platform and qRTPCR analysis.
At 98dpc the high dietary protein level stimulated the relative volume densities of the maternal tissue, in a sex specific manner, but had no effect on the fetal trophoblast cells. The LPERI diet increased the placental collagen proportion, which was also observed in the relative volume densities of the maternally derived collagen within the placentomes supporting female offspring. The HPERI diet also altered the vasculature by increasing the proportion of tissue occupied by blood vessels. Transcriptomic analyses of gene expression in the placentome showed the HPERI diet affected genes associated with inflammation and wound responses in the placentomes supporting male offspring. In the term placenta, the high protein diet increased the perimeter and area of blood vessels, but decreased proportion of tissue occupied by blood vessels. High protein also induced differential expression of genes associated with inflammation, a process integral to successful parturition.
In experiment 2, British nulliparous Angus cross heifers received control (10.4%) or high (14.5%) crude protein isocaloric diets for >60 days before slaughter, where ovaries and jugular blood were collected. Follicles were aspirated to remove follicular fluid (FF) and granulosa cells (GCs). Histological techniques were used to visualise the level of vascularisation in the corpus luteum (CL). Circulating serum metabolites and hormone levels were also determined by auto-analysis and ELISAs. Global gene expression of the ovarian granulosa cells (GCs) was determined using the Illumina platform and qRTPCR analysis. The high protein diet increased both the antral follicle count (AFC) and carcass quality, as measured by increased numbers of heifers falling into the higher grades. Analysis of serum and follicular fluid identified differences in urea, albumin, and non-esterified fatty acid levels induced by high dietary protein. Transcriptomic analysis of GC cells from control and high protein diets identified differential expression of genes associated with increased proliferation in the high protein group.
In conclusion, these studies showed that dietary protein level affected both placental and ovarian function. Furthermore, the dietary treatments impacted on gene expression associated with feto-placental growth and parturition
Perceptions of Multicultural Training in Predoctoral Internship Programs: A Survey of Interns and Training Directors
Multicultural training at internship sites is a critical component in the preparation of doctoral-level psychologists, so the quality of this training is of the utmost importance. In the following study, the authors examine multicultural training from the perspective of predoctoral interns and training directors at counseling center sites that offer a major or minor rotation in multicultural therapy. Results suggest that perspectives vary between interns and training directors and that there is a great difference in the type of criteria used by each site as evidence of a major or minor rotation. The need for more standardized criteria to define major and minor rotations and suggestions for the Association of Psychology Postdoctoral and Internship Centers, internship training directors, and prospective interns are discussed
Intern Self-Care: An Exploratory Study Into Strategy Use and Effectiveness
In this exploratory study, 363 interns were surveyed to assess the frequency of use and effectiveness of self-care strategies used during the internship year. Among the most frequently used strategies were family and friend social support, active problem solving, and humor. The most effective strategies were family and friend social support, seeking pleasurable experiences, and humor. A strong positive relationship was found between total scores for Frequency and Effectiveness subscales, and women reported significantly more use and effectiveness of strategies. Recommendations and resources are provided for interns and internship sites that seek to further understand and encourage intern self-care
Further evidence for fungivory in the Lower Devonian (Lochkovian) of the Welsh Borderland, UK
The recent demonstrations that widespread mid-Palaeozoic Prototaxites and other nematophytes had fungal affinities indicate that terrestrial fungi were important elements in carbon cycling in the Early Devonian. Here, we provide evidence for their participation in the recycling of nutrients by early terrestrial invertebrates. Evidence is in the form of coprolites, both those associated with nematophytes or containing their fragmentary remains. Cylindrical coprolites consistently associated with fungal mats are placed in a new ichnospecies, Bacillafaex myceliorum. Their contents are granular to amorphous, suggestive of complete digestion of the ingested hyphae, with the inference of possession of chitinases in the digestive tracts of the consumers. A further single example comprises a cluster of cylindrical bodies attached to the lower surface of a Nematothallus fragment. Here, homogenisation was less complete, with traces of hyphae remaining. Terrestrial animal fossils have not been found at the locality, but scorpions, pseudoscorpions, Opiliones, mites, centipedes (carnivores) and millipedes, and Collembola (detritivores) have been recorded from the slightly younger Rhynie cherts. Studies of fungivory in extant arthropods have concentrated on Collembola and, to a lesser extent, mites, but their faecal pellets are much smaller than the fossil examples. Millipedes, based on body size and faeces of extant forms, are considered more realistic producers, but little is known about fungal feeding in these animals. Regardless of the affinities of the producers, the diversity in morphology, sizes, aggregations, and composition of nematophyte-containing examples suggests that fungivory was an important component of carbon cycling in early terrestrial ecosystems
The Engagement Model of Person-Environment Interaction
This article focuses on growth-promoting aspects in the environment, and the authors propose a strength-based, dynamic model of person-environment interaction. The authors begin by briefly discussing the typical recognition of contextual variables in models that rely on the concept of person-environment fit. This is followed by a review of recent approaches to incorporating positive environmental factors in conceptualizations of human functioning. These approaches lead to an alternative model of person-environment interaction in which the engagement construct (i.e., the quality of a person-environment relationship determined by the extent to which negotiation, participation, and evaluation processes occur during the interaction) replaces the static notion of fit. Finally, the authors outline recommendations for overcoming environmental neglect in research, practice, and training
Anatomically preserved Silurian 'nematophytes' from the Welsh Borderland (UK)
Stratified charcoalified fragments of thalloid organisms with tripartite tissue construction have been isolated from the basal member of the Upper Silurian (upper Ludlow) Downton Castle Sandstone Formation, exposed near Ludlow, Shropshire (England) and are considered to have had fungal affinity. They are divided into two major groups. The more novel of these is characterized by a superficial cortex separated from a basal layer of interweaving hyphae by an intermediate zone of compressed indeterminate tissue and members are placed in a new taxon, Tristratothallus ludfordensis. In the second, the intermediate zone comprises hyphae arranged at right angles to the cortex (termed palisade). Some members resemble the tissue construction of Nematothallus described from the Lower Devonian (Lochkovian) of the Welsh Borderland and considered to belong to fungi, some of which were lichenized. A further type, which shows remains of polysporic asci, is thought to represent a fragment of an apothecium (a disc-shaped ascoma of an ascomycete) of a pezizomycete and is the earliest such record. Yet others are characterized by a perforate cortex with occasional protruding hyphae, tissue construction of which was also recorded in the Lower Devonian of the Welsh Borderland and considered to display fungal characteristics. Coalified āblack patchesā are common on bedding surfaces throughout the latest Silurian and Early Devonian and frequently are associated with basal embryophytes and tracheophytes. Those reported here are the oldest known with three-dimensional organization, studied via scanning electron microscopy (SEM) and attributed to fungi, and include some ascomycetes. Similar encrustations occur in even earlier rocks and may have been important constituents of the cryptogamic ground cover, which is postulated to have preceded higher plant life on land
The timescale of early land plant evolution
Establishing the timescale of early land plant evolution is essential for testing hypotheses on the coevolution of land plants and Earth's System. The sparseness of early land plant megafossils and stratigraphic controls on their distribution make the fossil record an unreliable guide, leaving only the molecular clock. However, the application of molecular clock methodology is challenged by the current impasse in attempts to resolve the evolutionary relationships among the living bryophytes and tracheophytes. Here, we establish a timescale for early land plant evolution that integrates over topological uncertainty by exploring the impact of competing hypotheses on bryophyte-tracheophyte relationships, among other variables, on divergence time estimation. We codify 37 fossil calibrations for Viridiplantae following best practice. We apply these calibrations in a Bayesian relaxed molecular clock analysis of a phylogenomic dataset encompassing the diversity of Embryophyta and their relatives within Viridiplantae. Topology and dataset sizes have little impact on age estimates, with greater differences among alternative clock models and calibration strategies. For all analyses, a Cambrian origin of Embryophyta is recovered with highest probability. The estimated ages for crown tracheophytes range from Late Ordovician to late Silurian. This timescale implies an early establishment of terrestrial ecosystems by land plants that is in close accord with recent estimates for the origin of terrestrial animal lineages. Biogeochemical models that are constrained by the fossil record of early land plants, or attempt to explain their impact, must consider the implications of a much earlier, middle Cambrian-Early Ordovician, origin
The influence of marine algae on iodine speciation in the coastaocean
Funding Information: This work was supported in part by grant CHE-1664657 from the National Science Foundation to CJC and FCK, the TOTAL Foundation (Paris) and the UK Natural Environment Research Council grants (NE/D521522/1, NE/ J023094/1, Oceans 2025 / WP 4.5) to FCK. We are also grateful for funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland). We thank Dr. M. L. Carter, SIO for help with collection of water samples at Scripps Pier, CƩsar O. Almeda-JƔuregui, CICESE for Ocean Data View plots and Dr. Avery Tatters, USC for the initial culture of Lingulodinium polyedra. A fellowship from the Hanse-Wissenschaftskolleg to CJC is also gratefully acknowledged.Peer reviewedPublisher PD
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