bluuebunny/crossref_metadata_2025 huggingface dataset:
Resource availability shapes fire‐filtered savannas
Authors: Dantas Vinícius de L. , Batalha Marco A. , França Helena , Pausas Juli G.
Published: November 2014

Questions

Humid savannas can be considered fire‐filtered landscapes because fire is very frequent (<10 yr return intervals) and only fire‐resistant species can occur. This flammable vegetation can be functionally heterogeneous, structurally and floristically patchy. We hypothesized that resource availability (mainly water and nutrient availabilities) accounted for most of the functional and phylogenetic spatial structure of communities across these savanna landscapes.

Location

Emas National Park, central Brazil.

Methods

We used individual‐based functional trait, phylogenetic and environmental data combined with spatial information to assess the main drivers and mechanisms of community functional change (turnover) in a large fire‐filtered savanna landscape. We used Mantel correlograms and a maximum rank correlation approach to assess the spatial structure and the subset of landscape factors that best predict compositional, phylogenetic, species‐based and individual‐based functional community turnovers and the mechanism by which they do operate.

Results

Communities were spatially structured across the landscape, presenting functional convergence at shorter distances and divergence at larger distances. All of the turnover metrics presented unique spatial structures and were correlated with a unique set of landscape predictors. Soil texture accounted for the largest fraction of the spatial structure, but soil N availability, pH, altitude and fire frequency were also important.

Conclusions

Our results support the idea that the patchy distribution of water and nutrients mediated by clay content shape community membership in fire‐filtered savannas, whereas current variations in fire frequency interact with resource availability to shift community attributes from species average trait values (intraspecific variability).
Disentangling the drivers of understorey species richness in eutrophic forest patches
Authors: Peppler‐Lisbach Cord , Beyer Linda , Menke Nadine , Mentges Andrea
Published: November 2014

Questions

What are the driving factors for the species richness of understorey herbs of isolated forest patches? How can the relative direct and indirect effects of patch area, site quality, habitat isolation and continuity be disentangled? What are the effects on different species groups?

Location

Eutrophic hardwood forest patches in northwestern Germany. The isolation of these patches results from extensive agricultural land use and prevailing poor soil conditions in the surrounding landscape. Thus, the patches are embedded within a matrix of both open habitats and species‐poor acidic forests.

Methods

We surveyed 76 eutrophic forest patches and recorded all understorey herb species. Several measured site variables were divided into soil and structural components, and into variables describing mean site conditions and site heterogeneity. Partial least squares structural equation modelling (PLS‐SEM) was employed to determine the direct and indirect effects of patch area, site heterogeneity, mean site conditions, isolation and habitat continuity on species richness of several species groups.

Results

The most important factor determining species richness was patch area, which showed the strongest direct effect on eutrophic forest specialist species. Richness of forest matrix species, which also occur in the surrounding forest areas, was not directly influenced by area. Soil heterogeneity as well as structural heterogeneity increased with area, but only soil heterogeneity was relevant for species richness. Soil heterogeneity was more important for forest species in general and stress tolerators than for generalist species, open habitat species, competitors and ruderals. Mean site conditions influenced species richness of generalists, open habitat species, competitors and nutrient‐demanding species. Isolation had a (negative) effect only on habitat specialists.

Conclusions

The relative effects of driving factors varied considerably between species groups. From our results for eutrophic forest specialists, we conclude that large and well‐connected habitat patches are especially important for the successful conservation of the unique and partly endangered flora of eutrophic hardwood forests.
Evidence of land‐sea transfer of the zoonotic pathogen Campylobacter to a wildlife marine sentinel species
Authors: Baily Johanna L. , Méric Guillaume , Bayliss Sion , Foster Geoffrey , Moss Simon E. , Watson Eleanor , Pascoe Ben , Mikhail Jane , Pizzi Romain , Goldstone Robert J. , Smith David G. E. , Willoughby Kim , Hall Ailsa J. , Sheppard Samuel K. , Dagleish Mark P.
Published: November 2014

Environmental pollution often accompanies the expansion and urbanization of human populations where sewage and wastewaters commonly have an impact on the marine environments. Here, we explored the potential for faecal bacterial pathogens, of anthropic origin, to spread to marine wildlife in coastal areas. The common zoonotic bacterium Campylobacter was isolated from grey seals (Halichoerus grypus), an important sentinel species for environmental pollution, and compared to isolates from wild birds, agricultural sources and clinical samples to characterize possible transmission routes. Campylobacter jejuni was present in half of all grey seal pups sampled (24/50 dead and 46/90 live pups) in the breeding colony on the Isle of May (Scotland), where it was frequently associated with histological evidence of disease. Returning yearling animals (19/19) were negative for C. jejuni suggesting clearance of infection while away from the localized colony infection source. The genomes of 90 isolates from seals were sequenced and characterized using a whole‐genome multilocus sequence typing (MLST) approach and compared to 192 published genomes from multiple sources using population genetic approaches and a probabilistic genetic attribution model to infer the source of infection from MLST data. The strong genotype‐host association has enabled the application of source attribution models in epidemiological studies of human campylobacteriosis, and here assignment analyses consistently grouped seal isolates with those from human clinical samples. These findings are consistent with either a common infection source or direct transmission of human campylobacter to grey seals, raising concerns about the spread of human pathogens to wildlife marine sentinel species in coastal areas.
Insecticide susceptibility of Anopheles coluzzii and Anopheles gambiae mosquitoes in Ibadan, Southwest Nigeria
Authors: OKORIE P. N. , ADEMOWO O. G. , IRVING H. , KELLY‐HOPE L. A. , WONDJI C. S.
Published: November 2014

The emergence of insecticide resistance in Anopheles (Diptera: Culicidae) mosquitoes has great implications for malaria control in Nigeria. This study aimed to determine the dynamics of insecticide susceptibility levels and the frequency of knock‐down resistance (kdr) mutations (L1014F) in wild Anopheles coluzzii Coetzee & Wilkerson sp. n. and Anopheles gambiae Giles from the Ojoo and Bodija areas of Ibadan, in southwest Nigeria. Insecticide susceptibility to pyrethroids, organophosphates, carbamates and organochlorines was assessed using World Health Organization (WHO) bioassays. A subset of the mosquitoes exposed to pyrethroids and DDT was used for species and molecular form identification; kdr genotyping was determined using the TaqMan real‐time polymerase chain reaction assay. The mosquitoes were resistant to pyrethroids and DDT but completely susceptible to organophosphates and carbamates. Bodija samples (n = 186) consisted of An. gambiae (91.4%) and An. coluzzii (8.1%) and included one An. coluzzii/An. gambiae hybrid specimen. All mosquitoes screened in Ojoo (n = 26) were An. gambiae. The 1014F kdr mutation was detected at frequencies of 24.5 and 5.8% in Bodija and Ojoo, respectively. No correlation was observed between kdr genotypes and resistance phenotypes. The results indicate that metabolic resistance probably plays an important role in the development of resistance and highlight the need to implement insecticide resistance management strategies.
The last three days of life: a comparison of pain management in the young old and the oldest old hospitalised patients using the Resident Assessment Instrument for Palliative Care
Authors: Steindal Simen Alexander , Bredal Inger Schou , Ranhoff Anette Hylen , Sørbye Liv Wergeland , Lerdal Anners
Published: November 2014

Background

Pain is a common symptom in older patients at the end of life. Little research has evaluated pain management among the oldest hospitalised dying patients.

Aims and objectives

To compare the pain characteristics documented by healthcare workers for the young old and the oldest old hospitalised patients and the types of analgesics administered in the last three days of life.

Design

A retrospective cross‐sectional comparative study.

Methods

The study included 190 patients from a Norwegian general hospital: 101 young old patients (aged 65–84 years) and 89 oldest old patients (aged 85–100 years). Data were extracted from electronic patient records (EPRs) using the Resident Assessment Instrument for Palliative Care.

Results

No significant differences were found between the young old and the oldest old patients with regard to pain characteristics. Pain intensity was poorly recorded in the EPRs. Most of the patients received adequate pain control. Morphine was the most frequently administered analgesic for dying patients. Compared to the oldest old patients, a greater proportion of the young old patients received paracetamol combined with codeine (OR = 3.25, 95% CI 1.02–10.40).

Conclusions

There appeared to be no differences in healthcare workers' documentation of pain characteristics in young old and oldest old patients, but young old patients were more likely to receive paracetamol in combination with codeine.

Implications for practice

A limitation of the study is the retrospective design and that data were collected from a single hospital. Therefore, caution should be taken for interpretation of the results. The use of systematic patient‐reported assessments in combination with feasible validated tools could contribute to more comprehensive documentation of pain intensity and improved pain control.
Older LGBT people's experiences and concerns with healthcare professionals and services in Ireland
Authors: Sharek Danika Burke , McCann Edward , Sheerin Fintan , Glacken Michele , Higgins Agnes
Published: November 2014

Background

The specific healthcare needs and concerns for older lesbian, gay, bisexual and transgender (LGBT) persons have not been explored to any degree within Ireland.

Aims and objectives

The aim of this paper, which is part of a larger study, is to detail older LGBT persons’ usage, experiences and concerns with accessing healthcare services, disclosing their LGBT identity to professionals, preferences for care and their suggestions for improvement in services, including nursing services.

Design

A mixed methods research design combining quantitative survey and qualitative interview approaches of equal significance was used.

Methods

144 respondents completed an 84‐item questionnaire concerning their use of healthcare services, experiences and needs. The qualitative phase involved in‐depth interviews where 36 participants’ experiences and concerns around health services were explored more in‐depth. Quantitative data were analysed using descriptive statistics. Qualitative analysis employed the constant comparative process to generate the leading themes.

Results

Only one in three participants believed that healthcare professionals have sufficient knowledge of LGBT issues, and less than half (43%) felt respected as an LGBT person by healthcare professionals. Although 26% had chosen not to reveal their LGBT status for fear of a negative response, many positive encounters of coming out to healthcare professionals were relayed in the interviews. LGBT persons have specific concerns around residential care, particularly in relation to the perception that the Irish healthcare services emanate a heteronormative culture.

Conclusions

Irish healthcare services need to reflect on how they currently engage with older LGBT persons at both an organisational and practitioner level. Consideration needs to be given to the specific concerns of ageing LGBT persons, particularly in relation to long‐term residential care.

Implications for practice

Healthcare practitioners need to be knowledgeable of, and sensitive to, LGBT issues.
Photobiological implications of melanin photoprotection after UVB‐induced tanning of human skin but not UVA‐induced tanning
Authors: Coelho Sergio G. , Yin Lanlan , Smuda Christoph , Mahns Andre , Kolbe Ludger , Hearing Vincent J.
Published: November 2014

Repetitive suberythemal UVA and/or UVB exposures were used to generate comparable UV‐induced tans in human skin over the course of 2 weeks. To evaluate the potential photoprotective values of those UVA‐ and/or UVB‐ induced tans and to avoid the confounding issue of residual UV‐induced DNA damage, we waited 1 week before challenging those areas with a 1.5 MED of UVA+UVB after which we measure DNA damage. The results show that the type of UV used to induce skin pigmentation affects the redistribution of melanin in the skin and/or de novo melanin synthesis. The UVA‐induced tans failed to even provide a minimal SPF of 1.5, which suggests that producing a tan with UVA‐rich sunlamps prior to a holiday or vacation is completely counterproductive.
Post‐renal transplant erythrocytosis: A case report
Authors: Almonte Mavel , Velásquez‐Jones Luis , Valverde Saúl , Carleton Bruce , Medeiros Mara
Published: November 2014

PTE is defined as hematocrit >51% or hemoglobin >17 g/dL after renal transplantation. Risk factors include native kidneys with adequate erythropoiesis pretransplant, smoking, renal artery stenosis, and cyclosporine treatment. We report the case of a 14‐yr‐old female kidney transplant patient, with triple therapy immunosuppression and stable graft function who developed PTE at 12 months post‐transplant with hemoglobin 17.3 g/dL, hematocrit 54.2%, stable graft function, and normotensive with normal cardiac echocardiogram and erythropoietin levels. The only risk factor found was tobacco use. As she had no spontaneous improvement, enalapril treatment was started at 19 months post‐transplant with a hemoglobin level of 17.5 g/dL and hematocrit 53%; by 23 months post‐transplant, hemoglobin lowered to 15 g/dL and hematocrit to 44.5% and continued to be in normal range thereafter. PTE is a rare condition in childhood and can be successfully treated with enalapril.
The gut mucosal immune response to Toxoplasma gondii
Authors: Cohen S. B. , Denkers E. Y.
Published: November 2014

As an orally acquired pathogen, the immune response to Toxoplasma gondii unfolds in the small intestinal mucosa. There, an array of regulatory and effector immune cells are elicited to combat the parasite through secretion of inflammatory mediators, normally resulting in host protection and pathogen control. Recent studies largely in mice have found that a productive immune response requires the combined recognition of parasite‐ and commensal‐derived antigens by mucosal leucocytes. However, despite the fine‐tuned regulatory mechanisms in place to prevent immunopathology, dysregulated responses can occur in genetically susceptible subjects, leading to lethal pro‐inflammatory‐mediated intestinal damage. Here, we describe the current understanding of the inflammatory players involved in orchestrating immunity or immunopathology in the intestine during the mucosal response to Toxoplasma infection.
Metabolic acclimation of source and sink tissues to salinity stress in bermudagrass (Cynodon dactylon)
Authors: Hu Longxing , Chen Liang , Liu Li , Lou Yanhong , Amombo Erick , Fu Jinmin
Published: November 2014

Salinity is one of the major environmental factors affecting plant growth and survival by modifying source and sink relationships at physiological and metabolic levels. Individual metabolite levels and/or ratios in sink and source tissues may reflect the complex interplay of metabolic activities in sink and source tissues at the whole‐plant level. We used a non‐targeted gas chromatography–mass spectrometry (GC‐MS) approach to study sink and source tissue‐specific metabolite levels and ratios from bermudagrass under salinity stress. Shoot growth rate decreased while root growth rate increased which lead to an increased root/shoot growth rate ratio under salt stress. A clear shift in soluble sugars (sucrose, glucose and fructose) and metabolites linked to nitrogen metabolism (glutamate, aspartate and asparagine) in favor of sink roots was observed, when compared with sink and source leaves. The higher shifts in soluble sugars and metabolites linked to nitrogen metabolism in favor of sink roots may contribute to the root sink strength maintenance that facilitated the recovery of the functional equilibrium between shoot and root, allowing the roots to increase competitive ability for below‐ground resource capture. This trait could be considered in breeding programs for increasing salt tolerance, which would help maintain root functioning (i.e. water and nutrient absorption, Na+ exclusion) and adaptation to stress.
Nicotine Exposure Alters the mRNA Expression of Notch Ligands in Dendritic Cells and Their Response to Th1‐/Th2‐Promoting Stimuli
Authors: Nouri‐Shirazi M. , Kahlden C. , Nishino P. , Guinet E.
Published: November 2014

Dendritic cells (DCs) utilize polarizing signals to instruct the differentiation of T helper (Th) cells into Th1 and Th2 effector cells: antigen‐specific ‘signal 1’, costimulatory ‘signal 2’ and polarizing cytokines ‘signal 3’. Accumulating evidence suggests the involvement of an additional signal, the Notch signalling pathway. We reported that in response to Th1‐promoting stimuli, both mouse and human DCs generated in the presence of the immune modulator nicotine (nicDCs) fail to support the development of effector memory Th1 cells. However, in response to Th2‐promoting stimuli, these nicDCs preferentially support the differentiation of antigen‐specific IL‐4‐producing Th2 effector cells. Here, we show that when compared to their control counterparts, immature mouse and human nicDCs display higher levels of the Notch ligands D1, D4 and J2 mRNA expression. In response to Th1‐ and Th2‐promoting stimuli, mouse nicDCs display higher levels of the Notch ligands D1, D4 and J2, while human nicDCs show higher levels of D1, D4 and J1 mRNA expression. Furthermore, both stimulated mouse and human nicDCs express higher CD86 to CD80 ratio and produce lower amount of IL‐12. Collectively, our data suggest that these changes in addition to an increase in Jagged expression correlate with the ability of nicDCs to modulate the Th1/Th2 balance in favour of Th2 generation.
The single water‐surface sweep estimation method accurately estimates very low (n = 4) to low–moderate (n = 25–100) and high (n > 100) Aedes aegypti (Diptera: Culicidae) pupae numbers in large water containers up to 13 times faster than the exhaustive sweep and total count method and without any sediment contamination
Authors: Romero‐Vivas C. M. , Llinás H. , Falconar A. K.
Published: November 2014

Objective

To confirm that a single water‐surface sweep‐net collection coupled with three calibration factors (2.6, 3.0 and 3.5 for 1/3, 2/3 and 3/3 water levels, respectively) (WSCF) could accurately estimate very low to high Aedes aegypti pupae numbers in water containers more rapidly than the exhaustive 5‐sweep and total count (ESTC) method recommended by WHO.

Methods

Both methods were compared in semi‐field trials using low (n = 25) to moderate (n = 50–100) pupae numbers in a 250‐l drum at 1/3, 2/3 and 3/3 water levels, and by their mean‐time determinations using 200 pupae in three 220‐ to 1024‐l water containers at these water levels. Accuracy was further assessed using 69.1% (393/569) of the field‐based drums and tanks which contained <100 pupae.

Results

The WSCF method accurately estimated total populations in the semi‐field trials up to 13.0 times faster than the ESTC method (all P < 0.001); no significant differences (all P‐values ≥ 0.05) were obtained between the methods for very low (n = 4) to low–moderate (n = 25–100) and high (n > 100) pupae numbers/container and without sediment disturbance.

Conclusion

The simple WSCF method sensitively, accurately and robustly estimated total pupae numbers in their principal breeding sites worldwide, containers with >20 l water volumes, significantly (2.7‐ to 13.0‐fold: all P‐values <0.001) faster than the ESTC method for very low to high pupae numbers/container without contaminating the clean water by sediment disturbance which is generated using the WHO‐recommended ESTC method. The WSCF method seems ideal for global community‐based surveillance and control programmes.
Factors influencing the decision to drop out of health insurance enrolment among urban slum dwellers in Ghana
Authors: Atinga Roger A. , Abiiro Gilbert Abotisem , Kuganab‐Lem Robert Bella
Published: November 2014

Objective

To identify the factors influencing dropout from Ghana's health insurance scheme among populations living in slum communities.

Methods

Cross‐sectional data were collected from residents of 22 slums in the Accra Metropolitan Assembly. Cluster and systematic random sampling techniques were used to select and interview 600 individuals who had dropped out from the scheme 6 months prior to the study. Descriptive statistics and multivariate logistic regression models were computed to account for sample characteristics and reasons associated with the decision to dropout.

Results

The proportion of dropouts in the sample increased from the range of 6.8% in 2008 to 34.8% in 2012. Non‐affordability of premium was the predominant reason followed by rare illness episodes, limited benefits of the scheme and poor service quality. Low‐income earners and those with low education were significantly more likely to report premium non‐affordability. Rare illness was a common reason among younger respondents, informal sector workers and respondents with higher education. All subgroups of age, education, occupation and income reported nominal benefits of the scheme as a reason for dropout.

Conclusion

Interventions targeted at removing bottlenecks to health insurance enrolment are salient to maximising the size of the insurance pool. Strengthening service quality and extending the premium exemption to cover low‐income families in slum communities is a valuable strategy to achieve universal health coverage.
Self‐transfer and mortality amongst adults lost to follow‐up in ART programmes in low‐ and middle‐income countries: systematic review and meta‐analysis
Authors: Wilkinson Lynne S. , Skordis‐Worrall Jolene , Ajose Olawale , Ford Nathan
Published: November 2014

Objective

To ascertain estimates of adult patients, recorded as lost to follow‐up (LTFU) within antiretroviral treatment (ART) programmes, who have self‐transferred care, died or truly stopped ART in low‐ and middle‐income countries.

Methods

PubMed, EMBASE, Web of Science, Science Direct, LILACS, IndMed and AIM databases (2003–2013) and IAS/AIDS conference abstracts (2011–2013) were searched for tracing studies reporting the proportion of traced patients found to have self‐transferred, died or stopped ART. These estimates were then combined using random‐effects meta‐analysis. Risk of bias was assessed through subgroup and sensitivity analyses.

Results

Twenty eight studies were eligible for inclusion, reporting true outcomes for 10 806 traced patients attending approximately 258 ART facilities. None were from outside sub‐Saharan Africa. Twenty three studies reported 4.5–54.4% traced LTFU patients self‐transferring care, providing a pooled estimate of 18.6% (95% CI 15.8–22.0%). A significant positive association was found between rates of self‐transfer and LTFU in the ART cohort. The pooled estimates for unreported deaths were 38.8% (95% CI 30.8–46.8%; 27 studies) and 28.6% (95% CI 21.9–36.0%; 20 studies) for patients stopping ART. A significant decrease in unreported deaths from 50.0% (95% CI 41.5–58.4%) to 30.0% (95% CI 21.1–38.9%) was found comparing study periods before and after 31 December 2007.

Conclusions

Substantial unaccounted for transfers and deaths amongst patients LTFU confirms that retention and mortality is underestimated where the true outcomes of LTFU patients are not ascertained.
Simple sequence repeat analysis of genetic diversity among Acetyl‐CoA carboxylase inhibitor‐resistant and ‐susceptible Echinochloa crus‐galli and E. oryzicola populations in Korea
Authors: Lee J , Park K W , Lee I‐Y , Kim C‐S , Kown O‐D , Park T‐S
Published: November 2014

Echinochloa species are amongst the most problematic weeds in rice fields of Korea. The steady reliance on the Acetyl‐CoA carboxylase (ACCase) and acetolactate synthase inhibiting herbicides for control of these weeds has led to resistance to these herbicides. The objective of this study was to assess the genetic diversity among populations of ACCase inhibitor‐resistant and ‐susceptible Echinochloa crus‐galli and E. oryzicola in Korea, to better understand their population structure and possible origins of resistance. Seven simple sequence repeat markers were applied to assess the genetic diversity between resistant and susceptible E. crus‐galli and E. oryzicola from 12 populations in Korea. Genetic diversity was slightly higher in the resistant group. The Unweighted Pair Group Method using Arithmetic algorithm (UPGMA) dendrogram generated two distinct clades. One clade consisted of Echinochloa spp. from three populations, i.e. Anmyeondo, Gimje 4 and Gongju, which are resistant and differentiated from the susceptible populations, and the other clade contained the rest of the populations. Structure modelling supported two clades of UPGMA clustering. Based on these data, we can infer that some resistant populations are greatly differentiated, whereas other resistant biotypes are still building up resistance in rice fields in Korea. Resistance traits will be fixed and continue to spread over time without proper control measures.
Can the parasitic weeds Striga asiatica and Rhamphicarpa fistulosa co‐occur in rain‐fed rice?
Authors: Kabiri S , Rodenburg J , Kayeke J , Van Ast A , Makokha D W , Msangi S H , Irakiza R , Bastiaans L
Published: November 2014

Striga asiatica and Rhamphicarpa fistulosa are important parasitic weeds of rain‐fed rice, partly distributed in similar regions in sub‐Saharan Africa (SSA). It is not evident whether their ecologies are mutually exclusive or partially overlapping. In Kyela, a rice‐growing area in south Tanzania where both parasites are present, three transects of about 3 km each across the upland–lowland continuum were surveyed in June 2012 and 2013. A total of 36 fields were categorised according to their position on the upland–lowland continuum as High, Middle or Low and soil samples were taken. In each field, parasitic and non‐parasitic weed species were identified in three quadrats. Additionally, in two pot experiments with four different moisture levels ranging from wilting point to saturation, influence of soil moisture on emergence and growth of parasites was investigated. Striga asiatica was observed in higher lying drier fields, while R. fistulosa was observed in the lower lying wetter fields. Furthermore, non‐parasitic weed species that were exclusive to S. asiatica‐infested fields are adapted to open well‐drained soils, while species that were exclusive to R. fistulosa fields are typical for wet soils. The experiments confirmed that S. asiatica is favoured by free‐draining soils and R. fistulosa by waterlogged soils. These results imply that changes in climate, specifically moisture regimes, will be crucial for future prevalence of these parasitic weeds. The non‐overlapping ecological range between their habitats suggests that their distribution and associated problems might remain separate. Thus, management strategies can be focused independently on either species.
A multilocus phylogeny of archiheterodont bivalves (Mollusca, Bivalvia, Archiheterodonta)
Authors: González Vanessa L. , Giribet Gonzalo
Published: November 2014

The bivalve clade Heterodonta encompasses more than half of the extant bivalve species and is presently considered a derived group of the modern bivalves (Newell ; Waller ). Heterodonta is subdivided into two major lineages, the hyperdiverse Euheterodonta and Archiheterodonta. The latter comprises four relatively small extant families: Astartidae, Carditidae, Condylocardiidae and Crassatellidae, whose relationships and internal phylogeny are poorly understood. We assessed the phylogeny of archiheterodont bivalves using a multilocus data set comprised of molecular sequence data from six loci (18S rRNA, 28S rRNA, cytochrome c oxidase subunit I, cytochrome b, internal transcribed spacer 2 and histone H3). Resultant data sets of ~4 Kb of concatenated molecular sequence data were analysed using probabilistic approaches (maximum likelihood and Bayesian inference) and parsimony direct optimization. We recovered strong support for the monophyly of Archiheterodonta, within which Astartidae is the sister group of Crassatellidae, and these two constitute the sister clade of Carditidae, which is paraphyletic with respect to Condylocardiidae. The relationships among the constituent species groups were evaluated in the context of the archiheterodont fossil record through the estimation of divergence times. Diversification times of archiheterodont families were congruent with bounded estimates of origins based on palaeontological data: Archiheterodonta diversified during the Devonian, 373.1 Ma (95% highest posterior density interval [HPD] 325.8–428.2); Crassatelloidea around the Carboniferous, 330.1 Ma (95% HPD 291.0–372.7); Crassatellidae around the Triassic, 224.0 (95% HPD 140.6–320.2); Astartidae around the Permian, 288.2 Ma (95% HPD 269.2–307.3); and Carditoidea around the Jurassic, 178.8 Ma (95% HPD 120.9–228.3).
Out of South America: phylogeny of non‐biting midges in the genus Labrundinia suggests multiple dispersal events to Central and North America
Authors: Silva Fabio L. , Ekrem Torbjørn , Fonseca‐Gessner Alaide A.
Published: November 2014

Non‐biting midges of the genus Labrundinia (Chironomidae: Tanypodinae) are minute dipterans with immature stages living in a variety of unpolluted water bodies, from small streams and ponds to lakes and bays. Extensively recorded in ecological studies, the genus comprises 39 species, all except one described from areas outside the Palearctic region. Internal structure among Labrundinia species was postulated by S. S. Roback, who recognized four species groups based on morphological characters of immature stages. We examined phylogenetic relationships among known Labrundinia species using partial DNA sequences of the nuclear protein‐coding gene CAD and morphological characters. Both analyses with Bayesian inference and parsimony methods recovered the monophyly of Labrundinia, strongly supported by five morphological synapomorphies. Internal relationships within the genus partly supported Roback's species groups with the addition of later described species. Biogeographical inferences were obtained by applying Bayesian binary MCMC (BBM) analysis and favoured a scenario where Labrundinia had its initial diversification in the Neotropical region and that current presence in the Nearctic region and southern South America is due to subsequent dispersal.
Sex steroid levels near the term of pregnancy do not alter lipopolysaccharide‐induced fever in oophorectomized rats
Authors: Finley Caitlin , Zhang Chunfen , Fewell James E.
Published: November 2014

New Findings

What is the central question of this study?

Do plasma concentrations of oestrogen and progesterone similar to those observed near the term of pregnancy alter basal core temperature or the core temperature response to bacterial pyrogen in oophorectomized rats?

What is the main finding and its importance?

Plasma concentrations of oestrogen and progesterone similar to those observed near the term of pregnancy do not alter basal core temperature or the overall febrile response to bacterial pyrogen in oophorectomized rats. Thus, our data do not support the hypothesis that sex steroids mediate the regulated decrease in basal core temperature or the attenuated/absent core temperature response to bacterial pyrogen observed in rats near the term of pregnancy.

Fever, an important component of the host's defence response to infection, is absent or attenuated in rats near the term of pregnancy concurrent with major changes in blood concentrations of the sex steroids, oestrogen and progesterone. The present experiments were carried out to determine the potential role of oestrogen and progesterone in mediating the altered core temperature response to bacterial pyrogen. For the experiments, oestrogen and progesterone were administered alone or in combination to oophorectomized, non‐pregnant rats in concentrations that mimicked plasma levels of these hormones measured in pregnant rats on days 17, 18, 19 and 20 of gestation. Treatment with oestrogen or progesterone alone or in combination did not alter basal core temperature or the overall febrile response (i.e. 12 h fever index) to an EC50 dose of Escherichia coli lipopolysaccharide (i.e. 20 μg kg−1). Administration of oestrogen did, however, influence the early core temperature response and increase the latency to fever following administration of lipopolysaccharide. Thus, our data provide evidence that although oestrogen may influence the early core temperature response to lipopolysaccharide, sex steroids in concentrations similar to those observed late in gestation do not alter the overall febrile response and are therefore unlikely to mediate the attenuated or absent febrile response to bacterial pyrogen in rats near the term of pregnancy.
Differential function of Gγ13 in rod bipolar and ON cone bipolar cells
Authors: Ramakrishnan Hariharasubramanian , Dhingra Anuradha , Tummala Shanti R. , Fina Marie E. , Li Jian J. , Lyubarsky Arkady , Vardi Noga
Published: November 2014

Key points

The G‐protein‐mediated metabotropic glutamate receptor 6 (mGluR6) signalling cascade is critical for light responses in all retinal ON bipolar cells. The present study evaluates the role of G‐protein subunit Gγ13 in ON bipolar cells by deleting the mouse Gng13 gene.

Gγ13 is a partner of Gβ3 in all types of retinal ON bipolar cells, and contributes to generating the light response.

Gγ13 also contributes to maintenance because, in its absence, the light response decreases with age.

Three independent functionality assessments (i.e. light response as measured by electroretinogram b‐waves, localization of GTPase activating proteins and deterioration of the light response with age) show that the contribution of Gγ13 is much greater in rod bipolar cells than in ON cone bipolar cells.

Our data also suggest that the contribution of Gγ13 to coupling mGluR6 to its effector is smaller than its contribution to maintaining GTPase activating protein localization.

Heterotrimeric G‐proteins (comprising Gα and Gβγ subunits) are critical for coupling of metabotropic receptors to their downstream effectors. In the retina, glutamate released from photoreceptors in the dark activates metabotropic glutamate receptor 6 (mGluR6) receptors in ON bipolar cells; this leads to activation of Go, closure of transient receptor potential melastatin 1 channels and hyperpolarization of these cells. Go comprises Gαo, Gβ3 and a Gγ. The best Gγ candidate is Gγ13, although functional data to support this are lacking. Thus, we tested Gγ13 function by generating Gng13−/− knockout (KO) mice, recording electroretinograms (ERG) and performing immunocytochemical staining. The amplitude of scotopic ERG b‐waves in KO mice was lower than in wild‐type (WT) mice. Furthermore, in both KO and WT mice, the ERG b‐wave decreased with age; this decrease was much more pronounced in KO mice. By contrast, the photopic ERG b‐waves in KO mice were hardly affected at any age. In KO mice retinas, immunostaining for Gβ3 and for the GTPase activating proteins RGS7, RGS11, R9AP and Gβ5 decreased significantly in rod bipolar cells but not in ON cone bipolar cells. Staining for Gαo and certain other cascade elements decreased only slightly. Analysis of our ON bipolar cDNA library showed that these cells express mRNAs for Gγ5, Gγ10 and Gγ11. Quantitative RT‐PCR of retinal cDNA showed greater values for these transcripts in retinas of KO mice, although the difference was not significant. Our results suggest that Gγ13 contributes to mGluR6 signalling in rod bipolar cells more than in ON cone bipolar cells, and that this contribution includes both coupling the receptor and maintaining a stable localization of the mGluR6‐related cascade elements.
Hypoxia, not pulmonary vascular pressure, induces blood flow through intrapulmonary arteriovenous anastomoses
Authors: Tremblay Joshua C. , Lovering Andrew T. , Ainslie Philip N. , Stembridge Mike , Burgess Keith R. , Bakker Akke , Donnelly Joseph , Lucas Samuel J.E. , Lewis Nia C.S. , Dominelli Paolo B. , Henderson William R. , Dominelli Giulio S. , Sheel A. William , Foster Glen E.
Published: November 2014

Key points

Blood flow through intrapulmonary arteriovenous anastomoses (IPAVA) is increased by acute hypoxia during rest by unknown mechanisms.

Oral administration of acetazolamide blunts the pulmonary vascular pressure response to acute hypoxia, thus permitting the observation of IPAVA blood flow with minimal pulmonary pressure change.

Hypoxic pulmonary vasoconstriction was attenuated in humans following acetazolamide administration and partially restored with bicarbonate infusion, indicating that the effects of acetazolamide on hypoxic pulmonary vasoconstriction may involve an interaction between arterial pH and .

We observed that IPAVA blood flow during hypoxia was similar before and after acetazolamide administration, even after acid–base status correction, indicating that pulmonary pressure, pH and are unlikely regulators of IPAVA blood flow.

Blood flow through intrapulmonary arteriovenous anastomoses (IPAVA) is increased with exposure to acute hypoxia and has been associated with pulmonary artery systolic pressure (PASP). We aimed to determine the direct relationship between blood flow through IPAVA and PASP in 10 participants with no detectable intracardiac shunt by comparing: (1) isocapnic hypoxia (control); (2) isocapnic hypoxia with oral administration of acetazolamide (AZ; 250 mg, three times a day for 48 h) to prevent increases in PASP; and (3) isocapnic hypoxia with AZ and 8.4% NaHCO3 infusion (AZ + HCO3–) to control for AZ‐induced acidosis. Isocapnic hypoxia (20 min) was maintained by end‐tidal forcing, blood flow through IPAVA was determined by agitated saline contrast echocardiography and PASP was estimated by Doppler ultrasound. Arterial blood samples were collected at rest before each isocapnic–hypoxia condition to determine pH, [HCO3–] and . AZ decreased pH (–0.08 ± 0.01), [HCO3–] (−7.1 ± 0.7 mmol l−1) and (−4.5 ± 1.4 mmHg; P < 0.01), while intravenous NaHCO3 restored arterial blood gas parameters to control levels. Although PASP increased from baseline in all three hypoxic conditions (P < 0.05), a main effect of condition expressed an 11 ± 2% reduction in PASP from control (P < 0.001) following AZ administration while intravenous NaHCO3 partially restored the PASP response to isocapnic hypoxia. Blood flow through IPAVA increased during exposure to isocapnic hypoxia (P < 0.01) and was unrelated to PASP, cardiac output and pulmonary vascular resistance for all conditions. In conclusion, isocapnic hypoxia induces blood flow through IPAVA independent of changes in PASP and the influence of AZ on the PASP response to isocapnic hypoxia is dependent upon the H+ concentration or .
Inositol‐1,4,5‐trisphosphate induced Ca2+ release and excitation–contraction coupling in atrial myocytes from normal and failing hearts
Authors: Hohendanner Felix , Walther Stefanie , Maxwell Joshua T. , Kettlewell Sarah , Awad Sawsan , Smith Godfrey L. , Lonchyna Vassyl A. , Blatter Lothar A.
Published: November 2014

Key points

Impaired calcium (Ca2+) signalling is the main contributor to depressed ventricular contractile function and occurrence of arrhythmia in heart failure (HF).

Here we report that in atrial cells of a rabbit HF model, Ca2+ signalling is enhanced and we identified the underlying cellular mechanisms. Enhanced Ca2+ transients (CaTs) are due to upregulation of inositol‐1,4,5‐trisphosphate receptor induced Ca2+ release (IICR) and decreased mitochondrial Ca2+ sequestration.

Enhanced IICR, however, together with an increased activity of the sodium–calcium exchange mechanism, also facilitates spontaneous Ca2+ release in form of arrhythmogenic Ca2+ waves and spontaneous action potentials, thus enhancing the arrhythmogenic potential of atrial cells.

Our data show that enhanced Ca2+ signalling in HF provides atrial cells with a mechanism to improve ventricular filling and to maintain cardiac output, but also increases the susceptibility to develop atrial arrhythmias facilitated by spontaneous Ca2+ release.

We studied excitation–contraction coupling (ECC) and inositol‐1,4,5‐triphosphate (IP3)‐dependent Ca2+ release in normal and heart failure (HF) rabbit atrial cells. Left ventricular HF was induced by combined volume and pressure overload. In HF atrial myocytes diastolic [Ca2+]i was increased, action potential (AP)‐induced Ca2+ transients (CaTs) were larger in amplitude, primarily due to enhanced Ca2+ release from central non‐junctional sarcoplasmic reticulum (SR) and centripetal propagation of activation was accelerated, whereas HF ventricular CaTs were depressed. The larger CaTs were due to enhanced IP3 receptor‐induced Ca2+ release (IICR) and reduced mitochondrial Ca2+ buffering, consistent with a reduced mitochondrial density and Ca2+ uptake capacity in HF. Elementary IP3 receptor‐mediated Ca2+ release events (Ca2+ puffs) were more frequent in HF atrial myoctes and were detected more often in central regions of the non‐junctional SR compared to normal cells. HF cells had an overall higher frequency of spontaneous Ca2+ waves and a larger fraction of waves (termed arrhythmogenic Ca2+ waves) triggered APs and global CaTs. The higher propensity of arrhythmogenic Ca2+ waves resulted from the combined action of enhanced IICR and increased activity of sarcolemmal Na+–Ca2+ exchange depolarizing the cell membrane. In conclusion, the data support the hypothesis that in atrial myocytes from hearts with left ventricular failure, enhanced CaTs during ECC exert positive inotropic effects on atrial contractility which facilitates ventricular filling and contributes to maintaining cardiac output. However, HF atrial cells were also more susceptible to developing arrhythmogenic Ca2+ waves which might form the substrate for atrial rhythm disorders frequently encountered in HF.
PGC‐1α mediates a rapid, exercise‐induced downregulation of glycogenolysis in rat skeletal muscle
Authors: Kim Sang Hyun , Koh Jin Ho , Higashida Kazuhiko , Jung Su Ryun , Holloszy John O. , Han Dong‐Ho
Published: November 2014

Key points

Long‐term endurance exercise training results in a reduction in the rates of muscle glycogen depletion and lactic acid accumulation during submaximal exercise; this adaptation is mediated by an increase in muscle mitochondria.

There is evidence suggesting that short‐term training induces adaptations that downregulate glycogenolysis before there is an increase in functional mitochondria.

We discovered that a single long bout of exercise induces decreases in expression of glycogenolytic and glycolytic enzymes in rat skeletal muscle; this adaptation results in slower rates of glycogenolysis and lactic acid accumulation in muscle during contractile activity.

Two additional days of training amplified the adaptive response, which appears to be mediated by PGC‐1α; this adaptation is biologically significant, because glycogen depletion and lactic acid accumulation are major causes of muscle fatigue.

Endurance exercise training can increase the ability to perform prolonged strenuous exercise. The major adaptation responsible for this increase in endurance is an increase in muscle mitochondria. This adaptation occurs too slowly to provide a survival advantage when there is a sudden change in environment that necessitates prolonged exercise. In the present study, we discovered another, more rapid adaptation, a downregulation of expression of the glycogenolytic and glycolytic enzymes in muscle that mediates a slowing of muscle glycogen depletion and lactic acid accumulation. This adaptation, which appears to be mediated by PGC‐1α, occurs in response to a single exercise bout and is further enhanced by two additional daily exercise bouts. It is biologically significant, because glycogen depletion and lactic acid accumulation are two of the major causes of muscle fatigue and exhaustion.
Stretch‐stimulated glucose transport in skeletal muscle is regulated by Rac1
Authors: Sylow Lykke , Møller Lisbeth L. V. , Kleinert Maximilian , Richter Erik A. , Jensen Thomas E.
Published: November 2014

Key points

Rac1 regulates stretch‐stimulated (i.e. mechanical stress) glucose transport in muscle.

Actin depolymerization decreases stretch‐induced glucose transport in skeletal muscle.

Rac1 is a required part of the mechanical stress‐component of the contraction‐stimulus to glucose transport in skeletal muscle.

An alternative to the canonical insulin signalling pathway for glucose transport is muscle contraction/exercise. Mechanical stress is an integrated part of the muscle contraction/relaxation cycle, and passive stretch stimulates muscle glucose transport. However, the signalling mechanism regulating stretch‐stimulated glucose transport is not well understood. We recently reported that the actin cytoskeleton regulating GTPase, Rac1, was activated in mouse muscle in response to stretching. Rac1 is a regulator of contraction‐ and insulin‐stimulated glucose transport, however, its role in stretch‐stimulated glucose transport and signalling is unknown. We therefore investigated whether stretch‐induced glucose transport in skeletal muscle required Rac1 and the actin cytoskeleton. We used muscle‐specific inducible Rac1 knockout mice as well as pharmacological inhibitors of Rac1 and the actin cytoskeleton in isolated soleus and extensor digitorum longus muscles. In addition, the role of Rac1 in contraction‐stimulated glucose transport during conditions without mechanical load on the muscles was evaluated in loosely hanging muscles and muscles in which cross‐bridge formation was blocked by the myosin ATPase inhibitors BTS and Blebbistatin. Knockout as well as pharmacological inhibition of Rac1 reduced stretch‐stimulated glucose transport by 30–50% in soleus and extensor digitorum longus muscle. The actin depolymerizing agent latrunculin B similarly decreased glucose transport in response to stretching by 40–50%. Rac1 inhibition reduced contraction‐stimulated glucose transport by 30–40% in tension developing muscle but did not affect contraction‐stimulated glucose transport in muscles in which force development was prevented. Our findings suggest that Rac1 and the actin cytoskeleton regulate stretch‐stimulated glucose transport and that Rac1 is a required part of the mechanical stress‐component of the contraction‐stimulus to glucose transport in skeletal muscle.