Spread and transmission of bacterial pathogens in experimental populations of the nematode Caenorhabditis elegans.

Caenorhabditis elegans is frequently used as a model species for the study of bacterial virulence and innate immunity. In recent years, diverse mechanisms contributing to the nematode's immune response to bacterial infection have been discovered. Yet despite growing interest in the biochemical and molecular basis of nematode-bacterium associations, many questions remain about their ecology. Although recent studies have demonstrated that free-living nematodes could act as vectors of opportunistic pathogens in soil, the extent to which worms may contribute to the persistence and spread of these bacteria has not been quantified. We conducted a series of experiments to test whether colonization of and transmission between C. elegans nematodes could enable two opportunistic pathogens (Salmonella enterica and Pseudomonas aeruginosa) to spread on agar plates occupied by Escherichia coli. We monitored the transmission of S. enterica and P. aeruginosa from single infected nematodes to their progeny and measured bacterial loads both within worms and on the plates. In particular, we analyzed three factors affecting the dynamics of bacteria: (i) initial source of the bacteria, (ii) bacterial species, and (iii) feeding behavior of the host. Results demonstrate that worms increased the spread of bacteria through shedding and transmission. Furthermore, we found that despite P. aeruginosa's relatively high transmission rate among worms, its pathogenic effects reduced the overall number of worms colonized. This study opens new avenues to understand the role of nematodes in the epidemiology and evolution of pathogenic bacteria in the environment.Some C. elegans and bacteria strains were provided by the Caenorhabditis Genetics Centre, which is funded by NIH Office of Research Infrastructure Programs (P40 OD010440). We thank Andrew Grant and Craig Winstanley for providing strains and reagents. We thank Mark Viney and two anonymous reviewers for helpful comments on the manuscript. This research was funded by a grant from the Biotechnology and Biological Sciences Research Council (grant number BB/I012222/1) to OR. OR also acknowledges funding from the Royal Society (University Research Fellowship).This is the author accepted manuscript. The final published version can be found on the publisher's website at: http://aem.asm.org/content/early/2014/06/23/AEM.01037-14.long Copyright © 2014, American Society for Microbiology. All Rights Reserve

Neighborhood Concerns and Mobilization Patterns of Homeowners and Neighborhood Associations

What issues and concerns of residential community associations (RCAs) compel them to mobilize and lobby local government? Do these patterns vary by RCA type? We argue that they do, and that neighborhood associations face different concerns than homeowners associations (HOAs). We also believe neighborhood associations are more likely to mobilize and interact with municipal government on behalf of the neighborhood. Using survey and interview data of neighborhood association and HOA presidents in Tallahassee, Florida, we find that neighborhood associations mobilize and interact with municipal government to a greater extent than HOAs. The issues and concerns that compel neighborhood associations to mobilize revolve around business/residential encroachment and crime. On the contrary, when HOAs do mobilize and interact with local government, the issues deal with the typical HOA concern of improving property values

Hummingbirds and the plants they visit in the Tehuacán-Cuicatlán Biosphere Reserve, Mexico

We describe the relative abundance, plant species visited, and plant communities used by hummingbird species inhabiting the Tehuacán-Cuicatlán Biosphere Reserve, a semiarid area in South-central Mexico. We recorded 14 hummingbird species and 35 plant species distributed in 4 plant communities during our study. We found 86 different hummingbird-plant interactions. Amazilia violiceps and Cynanthus latirostris were the most common hummingbirds, while C. latirostris, A. violiceps, and Cynanthus sordidus were the hummingbirds that visited more plant species. Hummingbirds were distributed differentially between plant communities inside the reserve, with 12 species being present in the arboreal plant community of the lowlands, 11 both in cactus forest and perennial spine shrub plants, and 6 in perennial unarmed shrub plants. Cercidium praecox (Fabaceae) was the plant species with the highest number of visiting hummingbird species (10 species). Cactus forest and perennial spine shrub plants were the plant communities with largest number of possible interactions (57 and 51, respectively). The mean connectance value of the interaction matrix was similar between plant communities (near to 22%), but lower than those reported previously in other places. In the Tehuacán-Cuicatlán Biosphere Reserve the hummingbird-plant interaction system will be preserved if the hummingbirds C. latirostris, A. violiceps, C. sordidus, and L. clemenciae, and the plants C. praecox, I. arborescens, E. chiotilla, and N. glauca, are protected

Psychological response of family members of patients hospitalised for influenza A/H1N1 in Oaxaca, Mexico

<p>Abstract</p> <p>Background</p> <p>The A/H1N1 pandemic originated in Mexico in April 2009, amid high uncertainty, social and economic disruption, and media reports of panic. The aim of this research project was to evaluate the psychological response of family primary caregivers of patients hospitalised in the Intensive Care Unit (ICU) with suspected influenza A/H1N1 to establish whether there was empirical evidence of high adverse psychological response, and to identify risk factors for such a response. If such evidence was found, a secondary aim was to develop a specific early intervention of psychological support for these individuals, to reduce distress and possibly lessen the likelihood of post-traumatic stress disorder (PTSD) in the longer term.</p> <p>Methods</p> <p>Psychological assessment questionnaires were administered to the family primary caregivers of patients hospitalised in the ICU in the General Hospital of Zone 1 of the Mexican Institute for Social Security (IMSS), Oaxaca, Mexico with suspected influenza A/H1N1, during the month of November 2009. The main outcome measures were ratings of reported perceived stress (PSS-10), depression (CES-D), and death anxiety (DAQ). Data were subjected to simple and multiple linear regression analysis to identify risk factors for adverse psychological response.</p> <p>Results</p> <p>Elevated levels of perceived stress and depression, compared to population normative data, and moderate levels of death anxiety were noted. Levels of depression were similar to those found in comparable studies of family members of ICU patients admitted for other conditions. Multiple regression analysis indicated that increasing age and non-spousal family relationship were significantly associated with depression and perceived stress. Female gender, increasing age, and higher levels of education were significantly associated with high death anxiety. Comparisons with data collected in previous studies in the same hospital ICU with groups affected by a range of other medical conditions indicated that the psychological response reported in this study was generally lower.</p> <p>Conclusions</p> <p>Data indicated that, contrary to widely publicised reports of 'panic' surrounding A/H1N1, that some of those most directly affected did not report excessive psychological responses; however, we concluded that there was sufficient evidence to support provision of limited psychological support to family caregivers.</p

A Novel STAT3 Mutation in a Qatari Patient With Hyper-IgE Syndrome

Autosomal dominant hyper-IgE syndrome caused by mutations in the transcription factor STAT3 (AD-HIES) is characterized by a collection of immunologic and non-immune features including eczema, recurrent infections, elevated IgE levels, and connective tissue anomalies. We report the case of a Qatari child with a history of recurrent staphylococcal skin infections since infancy, who was found to have a novel, de novo mutation in STAT3 (c.1934T&gt;A, p.L645Q). The absence of mucocutaneous candidiasis and undetectable IgE levels until the age of 7 years prolonged the time to molecular confirmation of the cause for the patient's immune deficiency. STAT3 p.L645Q was found to have decreased transcriptional capacity. The patient also had low levels of Th17 cells and STAT3 phosphorylation was impaired in patient-derived cells. Nearly 100 unique mutations in STAT3 have been reported in association with AD-HIES

Prevention of bronchial hyperreactivity in a rat model of precapillary pulmonary hypertension

<p>Abstract</p> <p>Background</p> <p>The development of bronchial hyperreactivity (BHR) subsequent to precapillary pulmonary hypertension (PHT) was prevented by acting on the major signalling pathways (endothelin, nitric oxide, vasoactive intestine peptide (VIP) and prostacyclin) involved in the control of the pulmonary vascular and bronchial tones.</p> <p>Methods</p> <p>Five groups of rats underwent surgery to prepare an aorta-caval shunt (ACS) to induce sustained precapillary PHT for 4 weeks. During this period, no treatment was applied in one group (ACS controls), while the other groups were pretreated with VIP, iloprost, tezosentan via an intraperitoneally implemented osmotic pump, or by orally administered sildenafil. An additional group underwent sham surgery. Four weeks later, the lung responsiveness to increasing doses of an intravenous infusion of methacholine (2, 4, 8 12 and 24 μg/kg/min) was determined by using the forced oscillation technique to assess the airway resistance (Raw).</p> <p>Results</p> <p>BHR developed in the untreated rats, as reflected by a significant decrease in ED₅₀, the equivalent dose of methacholine required to cause a 50% increase in Raw. All drugs tested prevented the development of BHR, iloprost being the most effective in reducing both the systolic pulmonary arterial pressure (Ppa; 28%, p = 0.035) and BHR (ED₅₀= 9.9 ± 1.7 vs. 43 ± 11 μg/kg in ACS control and iloprost-treated rats, respectively, p = 0.008). Significant correlations were found between the levels of Ppa and ED₅₀(R = -0.59, p = 0.016), indicating that mechanical interdependence is primarily responsible for the development of BHR.</p> <p>Conclusions</p> <p>The efficiency of such treatment demonstrates that re-establishment of the balance of constrictor/dilator mediators via various signalling pathways involved in PHT is of potential benefit for the avoidance of the development of BHR.</p

Basic Demography of Caenorhabditis remanei Cultured under Standard Laboratory Conditions

Species of the Caenorhabditis genus have been used as model systems in genetics and molecular research for more than 30 years. Despite this, basic information about their demography, in the wild and in the lab, has remained unknown until very recently. Here, we provide for the first time a closely quantified life-cycle of the gonochoristic nematode C. remanei. Using C. elegans protocols, modified for an outcrossing nematode, we estimated the basic demography for individuals of two strains (JU724 and MY12-G) which were recently isolated from the wild. We used a half-sib breeding design to estimate the phenotypic variance of traits of related (within line) and unrelated individuals (between lines) of the two strains cultured in a common environment in the lab. Comparisons between these strains showed that JU724 was characterized by significantly lower overall lifetime fecundity and by differences in age-specific fecundity relative to MY12-G, but there were no differences in their life expectancy and reproductive lifespan. We found high phenotypic variance among all traits. The variance within lines was relatively high compared to the low variation between lines. We suggest this could be the result of high gene flow in these wild-type strains. Finally, comparisons between species suggest that, despite the differences in reproductive strategies (i.e., sex ratios, lifetime fecundity), C. remanei has developmental time similar to the hermaphroditic N2 strain of C. elegans

Estimación gravimétrica del grosor cortical en el Golfo de California

En este estudio se implementa la inversión 3D de datos gravimétricos satelitales mediante el programa 3DINVER.M para modelar el grosor de la corteza en el rift del Golfo de California. Este rift oblicuo separa dextralmente la península de Baja California del continente de Norteamérica desde el Mioceno, periodo en el que se produjo el cambio desde un régimen tectónico fundamentalmente extensional al transtensional presente. A lo largo de su eje, el rift del Golfo de California se encuentra en una fase de oceanización incipiente en varias cuencas de su mitad meridional, mientras que al norte la presencia de corteza oceánica es controvertida. A consecuencia de esta particularidad, la corteza de la cuenca marina del Golfo y la de regiones terrestres adyacentes presentan importantes diferencias de densidad y grosor, siendo ambos parámetros fundamentales del método empleado, y, por ello, se realiza un modelo específico para cada dominio. Los modelos de grosor cortical generados se compararon con las estimaciones puntuales previas basadas en métodos sísmicos, obteniéndose que el 98% de los puntos confrontados del modelo marino y el 87% del terrestre se ajustan a un rango de ±6 km de diferencia, con diferencias promedio absolutas de 1.5 km y de 3.5 km respectivamente. La cuenca del Golfo en los modelos evoluciona a lo largo de su eje y desde el sur al norte desde una corteza híper-adelgazada (~8−12 km), característica de corteza oceánica a transicional, hasta una corteza continental moderadamente adelgazada (~12−18 km). En al área extendida circundante, que completa la denominada como Provincia Extensional del Golfo, la corteza continental varía habitualmente entre ~15 y ~28 km, mientras que en sus flancos la corteza llega a alcanzar los ~35−40 km en los dominios más engrosados (Sierra Madre Occidental y Meseta del Colorado). Asimismo, con base en las estimaciones del grosor cortical y la geología regional, se propone una nueva demarcación para la Provincia Extensional del Golfo.</jats:p

Evaluation of the common cuttlefish’s behaviour and colour change as sublethal endpoints for the assessment of endocrine disruptors

International audienc