Digestibility of Duddingtonia flagrans chlamydospores in ruminants: in vitro and in vivo studies

<p>Abstract</p> <p>Background</p> <p>The use of <it>Duddingtonia flagrans </it>as a tool for the biological control of gastrointestinal nematodes (GIN) is a promising alternative to anthelmintics. The chlamydospores of <it>D. flagrans </it>are orally dosed and their thick cell wall gives them the capacity to resist digestion and pass through the gastrointestinal tract (GIT). Chlamydospores reaching the faeces are able to germinate and trap nematode larvae. The efficacy of this control method is based on reducing the numbers of infective larvae leaving the faeces. Techniques have recently been developed for quantifying the numbers of chlamydospores in faeces. As the number of non-digested spores could be relevant in the design and optimization of dosing programmes for the control of GIN infective larvae, the aim of the present study was to estimate the loss of <it>D. flagrans </it>chlamydospores during their passage through the ruminant gastrointestinal tract using <it>in vitro </it>and <it>in vivo </it>techniques.</p> <p>Results</p> <p>After <it>in vitro </it>rumen digestion, chlamydospore recovery was not different from the quantity originally incubated (undigested spores) (P > 0.05). <it>In vitro </it>rumen+abomasum digestion caused nearly 36% loss of the chlamydospores originally incubated (P < 0.05). Germination of chlamydospores classified as viable was 24.3%. Chlamydospores classified as non-viable did not germinate. Rumen digestion resulted in more spore germination (R1 = 35.7% and R2 = 53.3%) compared to no digestion (time 0 h = 8.7%). Subsequent abomasal digestion reduced germination (R1+A = 25%) or stopped it (R2+A = 0%). <it>In vivo </it>apparent chlamydospore digestibility in sheep showed a loss of 89.7% of the chlamydospores (P < 0.05).</p> <p>Conclusions</p> <p>The loss of chlamydospores was evident under <it>in vitro </it>and <it>in vivo </it>conditions. Negligible amounts of spores were lost during the <it>in vitro </it>rumen digestion. However, <it>in vitro </it>rumen+abomasum digestion resulted in a chlamydospore loss of approximately 36%. <it>In vivo </it>passage through the sheep GIT resulted in a total loss of 89.7% of the orally administered spores.</p

Nitric oxide blocks the development of the human parasite Schistosoma japonicum

Human schistosomiasis, caused by Schistosoma species, is a major public health problem affecting more than 700 million people in 78 countries, with over 40 mammalian host reservoir species complicating the transmission ecosystem. The primary cause of morbidity is considered to be granulomas induced by fertilized eggs of schistosomes in the liver and intestines. Some host species, like rats (Rattus norvegicus), are naturally intolerant to Schistosoma japonicum infection, and do not produce granulomas or pose a threat to transmission, while others, like mice and hamsters, are highly susceptible. The reasons behind these differences are still a mystery. Using inducible nitric oxide synthase knockout (iNOS−/−) Sprague–Dawley rats, we found that inherent high expression levels of iNOS in wild-type (WT) rats play an important role in blocking growth, reproductive organ formation, and egg development in S. japonicum, resulting in production of nonfertilized eggs. Granuloma formation, induced by fertilized eggs in the liver, was considerably exacerbated in the iNOS−/− rats compared with the WT rats. This inhibition by nitric oxide acts by affecting mitochondrial respiration and energy production in the parasite. Our work not only elucidates the innate mechanism that blocks the development and production of fertilized eggs in S. japonicum but also offers insights into a better understanding of host–parasite interactions and drug development strategies against schistosomiasis

LA INMIGRANTE Y SU SALUD, UN CAMINO POR RECORRER EN EL S. XXI

Introduction The demand for health care in Murcia has made us question how immigrants perceive our health care system. Thus the importance of observing the behavior of immigrants, as they face obstacles appearing because they are women and belong to a different culture, an issue that can be difficult for health care workers. Methodology: The study was conducted with a sample of 41 female immigrants in the Murcia region. Five introductory interviews were carried out as an introductory tool in this observational descriptive study. After obtaining the results some forms were filled out consisting of closed questions concerning the attention given, obstacles and gender issues when it comes to receiving their health care. As a criterion of exclusion, there was an absence of males during the questioning so as not to affect the response of the interviewee. Discussion The vast majority of those interviewed have difficulty communicating with health care staff. Dissatisfaction with the service provided could arise. It shows the great importance of a mediator between professionals and female immigrants. Therefore, health care services should be open to all people in our society, not only in situations of illness but also to improve health. Conclusions • Encourage the need for a multicultural mediator in all places where health care is provided. •Required that health professionals who provide care should be trained in cultural aspects. •Health policy towards immigration groups should be implemented.Introducción La demanda de atención sanitaria en nuestra Región nos ha llevado a cuestionarnos cómo las inmigrantes perciben nuestra atención sanitaria, por ello la importancia de observar el comportamiento de las inmigrantes ante los obstáculos que se les presentan por el hecho de ser mujeres y de pertenecer a una cultura diferente y que pueda ser objeto de dificultad para el personal sanitario. Metodología El estudio se ha realizado con una muestra de 41 mujeres inmigrantes de la Región de Murcia de tipo observacional descriptivo, en el que se hicieron 5 entrevistas como herramienta introductoria. Tras los resultados obtenidos se han llevado a cabo unos formularios que constan de preguntas cerradas referentes a la atención prestada, obstáculos y razón de sexo a la hora de recibir su atención sanitaria. Como criterio de exclusión, ausencia del género masculino durante las preguntas-respuestas para no influir en la respuesta de la entrevistada. Discusión La gran mayoría de las entrevistadas presentan dificultades para comunicarse con el personal sanitario. Pudiendo provocar una insatisfacción del servicio que se le presta. Se muestra la gran importancia de una persona mediadora entre profesionales y mujeres inmigrantes. Por tanto, los servicios de Salud deben estar abiertos a todas las personas que configuran nuestra sociedad, no solamente en situación de enfermedad sino también para mejorar la salud. Conclusiones • Potenciar la necesidad de un mediador multicultural en todos los centros donde se presta atención sanitaria. • Exigencia curricular de formación en aspectos culturales a los profesionales sanitarios que prestan sus cuidados. • Se debería proyectar la política sanitaria hacia los grupos inmigratorios

The Organizational Account of Function is an Etiological Account of Function

The debate on the notion of function has been historically dominated by dispositional and etiological accounts, but recently a third contender has gained prominence: the organizational account. This original theory of function is intended to offer an alternative account based on the notion of self-maintaining system. However, there is a set of cases where organizational accounts seem to generate counterintuitive results. These cases involve cross-generational traits, that is, traits that do not contribute in any relevant way to the self-maintenance of the organism carrying them, but instead have very important effects on organisms that belong to the next generation. We argue that any plausible solution to the problem of cross-generational traits shows that the organizational account just is a version of the etiological theory and, furthermore, that it does not provide any substantive advantage over standard etiological theories of function

The Genomics of Speciation in Drosophila: Diversity, Divergence, and Introgression Estimated Using Low-Coverage Genome Sequencing

In nature, closely related species may hybridize while still retaining their distinctive identities. Chromosomal regions that experience reduced recombination in hybrids, such as within inversions, have been hypothesized to contribute to the maintenance of species integrity. Here, we examine genomic sequences from closely related fruit fly taxa of the Drosophila pseudoobscura subgroup to reconstruct their evolutionary histories and past patterns of genic exchange. Partial genomic assemblies were generated from two subspecies of Drosophila pseudoobscura (D. ps.) and an outgroup species, D. miranda. These new assemblies were compared to available assemblies of D. ps. pseudoobscura and D. persimilis, two species with overlapping ranges in western North America. Within inverted regions, nucleotide divergence among each pair of the three species is comparable, whereas divergence between D. ps. pseudoobscura and D. persimilis in non-inverted regions is much lower and closer to levels of intraspecific variation. Using molecular markers flanking each of the major chromosomal inversions, we identify strong crossover suppression in F1 hybrids extending over 2 megabase pairs (Mbp) beyond the inversion breakpoints. These regions of crossover suppression also exhibit the high nucleotide divergence associated with inverted regions. Finally, by comparison to a geographically isolated subspecies, D. ps. bogotana, our results suggest that autosomal gene exchange between the North American species, D. ps. pseudoobscura and D. persimilis, occurred since the split of the subspecies, likely within the last 200,000 years. We conclude that chromosomal rearrangements have been vital to the ongoing persistence of these species despite recent hybridization. Our study serves as a proof-of-principle on how whole genome sequencing can be applied to formulate and test hypotheses about species formation in lesser-known non-model systems

Simulation of impulse response for indoor visible light communications using 3D CAD models

n this article, a tool for simulating the channel impulse response for indoor visible light communications using 3D computer-aided design (CAD) models is presented. The simulation tool is based on a previous Monte Carlo ray-tracing algorithm for indoor infrared channel estimation, but including wavelength response evaluation. The 3D scene, or the simulation environment, can be defined using any CAD software in which the user specifies, in addition to the setting geometry, the reflection characteristics of the surface materials as well as the structures of the emitters and receivers involved in the simulation. Also, in an effort to improve the computational efficiency, two optimizations are proposed. The first one consists of dividing the setting into cubic regions of equal size, which offers a calculation improvement of approximately 50% compared to not dividing the 3D scene into sub-regions. The second one involves the parallelization of the simulation algorithm, which provides a computational speed-up proportional to the number of processors used

Analytical Framework for Identifying and Differentiating Recent Hitchhiking and Severe Bottleneck Effects from Multi-Locus DNA Sequence Data

Hitchhiking and severe bottleneck effects have impact on the dynamics of genetic diversity of a population by inducing homogenization at a single locus and at the genome-wide scale, respectively. As a result, identification and differentiation of the signatures of such events from DNA sequence data at a single locus is challenging. This paper develops an analytical framework for identifying and differentiating recent homogenization events at multiple neutral loci in low recombination regions. The dynamics of genetic diversity at a locus after a recent homogenization event is modeled according to the infinite-sites mutation model and the Wright-Fisher model of reproduction with constant population size. In this setting, I derive analytical expressions for the distribution, mean, and variance of the number of polymorphic sites in a random sample of DNA sequences from a locus affected by a recent homogenization event. Based on this framework, three likelihood-ratio based tests are presented for identifying and differentiating recent homogenization events at multiple loci. Lastly, I apply the framework to two data sets. First, I consider human DNA sequences from four non-coding loci on different chromosomes for inferring evolutionary history of modern human populations. The results suggest, in particular, that recent homogenization events at the loci are identifiable when the effective human population size is 50000 or greater in contrast to 10000, and the estimates of the recent homogenization events are agree with the “Out of Africa” hypothesis. Second, I use HIV DNA sequences from HIV-1-infected patients to infer the times of HIV seroconversions. The estimates are contrasted with other estimates derived as the mid-time point between the last HIV-negative and first HIV-positive screening tests. The results show that significant discrepancies can exist between the estimates