1,445 research outputs found
Sphaeropsis sapinea and Botryosphaeria dothidea endophytic in Pinus spp. and Eucalyptus spp. in South Africa
Sphaeropsis sapinea (Fr.: Fr.) Dyko & B. Sutton and the anamorph of Botryosphaeria dothidea (Moug.) Ces. et De Not. are morphologically and ecologically similar fungi that cause serious canker and die-back diseases of Pinus and Eucalyptus spp. respectively in South Africa. In this article, the presence of both these fungi as symptomless endophytes In healthy pine and eucafypt tissue was demonstrated. Sphaeropsis sapinea was present in 50% of young, green P patula Schl. et Cham., and 90% of P. radiata D. Don cones. In contrast, it was virtually absent from the cones of P. elliottii Engalm. et Vasey and P. taeda L. Botryosphaeria dothidea, on the other hand, was found to be common in all the Eucalyptus spp. tested, occurring in 93% of E. smithii R. T. Bak., 77% of E. camaldulensis Dehnh., 63% of E. grandis Hill ex Maid, and 57% of E. nitens (Deane et Maid.) Maid, leaves tested. The enigma of the rapid Ingress of both these fungi In stressed or damaged trees might therefore be explained by their endophytic habit
The thermal characteristics of roofs: policy, installation and performance
This paper investigates the in-situ performance of UK cold pitched roof structures through a case study dwelling of typical
construction using site survey, and estimation of U-values through simple calculation and from measured heat flow data. Significant
increases of U-values resulted from under- and un-insulated areas due to installation issues, whilst a higher than expected estimated
thermal resistance of the roof space and structure was also noted, potentially associated with heat gains. Both issues are expected
to be observed more widely in the stock and contribute to a performance gap for roof insulation
Experimental chronic noise is related to elevated fecal corticosteroid metabolites in lekking male greater Sage-Grouse (Centrocercus urophasianus).
There is increasing evidence that individuals in many species avoid areas exposed to chronic anthropogenic noise, but the impact of noise on those who remain in these habitats is unclear. One potential impact is chronic physiological stress, which can affect disease resistance, survival and reproductive success. Previous studies have found evidence of elevated stress-related hormones (glucocorticoids) in wildlife exposed to human activities, but the impacts of noise alone are difficult to separate from confounding factors. Here we used an experimental playback study to isolate the impacts of noise from industrial activity (natural gas drilling and road noise) on glucocorticoid levels in greater sage-grouse (Centrocercus urophasianus), a species of conservation concern. We non-invasively measured immunoreactive corticosterone metabolites from fecal samples (FCMs) of males on both noise-treated and control leks (display grounds) in two breeding seasons. We found strong support for an impact of noise playback on stress levels, with 16.7% higher mean FCM levels in samples from noise leks compared with samples from paired control leks. Taken together with results from a previous study finding declines in male lek attendance in response to noise playbacks, these results suggest that chronic noise pollution can cause greater sage-grouse to avoid otherwise suitable habitat, and can cause elevated stress levels in the birds who remain in noisy areas
Causes and consequences of variability in peptide mating pheromones of ascomycete fungi
The reproductive genes of fungi, like those of many other organisms, are thought to diversify
rapidly. This phenomenon could be associated with the formation of reproductive barriers and
speciation. Ascomycetes produce two classes of mating-type-specific peptide pheromones. These
are required for recognition between the mating types of heterothallic species. Little is known
regarding the diversity or the extent of species-specificity in pheromone peptides among these
fungi. We compared the putative protein-coding DNA sequences of the two pheromone classes
from 70 species of Ascomycetes. The dataset included previously-described pheromones and
putative pheromones identified from genomic sequences. In addition, pheromone genes from
twelve Fusarium species in the Gibberella fujikuroi complex were amplified and sequenced.
Pheromones were largely conserved among species in this complex and, therefore, cannot alone
account for the reproductive barriers observed between these species. In contrast, pheromone
peptides were highly diverse among many other Ascomycetes, with evidence for both positive
diversifying selection and relaxed selective constraint. Repeats of the α-factor-like pheromone,
which occur in tandem arrays of variable copy number, were found to be conserved through
purifying selection and not concerted evolution. This implies that sequence-specificity may be
important for pheromone reception and that inter-specific differences may indeed be associated
with functional divergence. Our findings also suggest that frequent duplication and loss causes
the tandem-repeats to experience “birth-and-death” evolution, which could in fact facilitate interspecific
divergence of pheromone peptide sequences.The National Research Foundation (NRF), the DST/NRF Centre of
Excellence in Tree Health Biotechnology (CTHB), the University of Pretoria and the Tree
Protection Cooperative Programme (TPCP).http://mbe.oxfordjournals.org/nf201
Eight new Leptographium species associated with tree-infesting bark beetles in China
Leptographium spp. are anamorphs of Grosmannia residing in the order Ophiostomatales. These fungi are typically associated with bark-beetles and are common causal agents of sapstain in lumber and some are important tree pathogens. In this study, Leptographium spp. associated with bark beetles collected during a survey in Jilin and Yunnan provinces of China, were identified. Identifications were achieved using comparisons of morphological characters and DNA sequence data for the ITS2-partial LSU rDNA region, as well as the β-tubulin and EF-1α gene regions. Eight unknown species of Leptographium are recognised and described from conifer and hardwood hosts, associated with beetles including Ips subelongatus, Tomicus yunnanensis, Hylurgops minor, Polygraphus verrucifrons and a Pissodes sp. Six of the new species are morphologically and phylogenetically related to species known to occur in Asia such as G. yunnanense, L. bhutanense, L. bistatum and L. sinoprocerum. The remaining two taxa are related to those in a group containing G. americana and L. abietinum, found in North America. This study also provides the first report of L. pineti on Pinus kesiya in China
Structure and evolution of the Fusarium mating type locus : new insights from the Gibberella fujikuroi complex
Mating type genes are central to sexual reproduction and compatibility in Ascomycete fungi. However the “MAT” loci experience unique evolutionary pressures that can result in rapid divergence and enhanced inter-specific gene-flow (lateral gene transfer). In this study, molecular evolution of MAT loci was considered using the genus Fusarium (Teleomorph: Gibberella) as a model. Both MAT1-1 and MAT1-2 “idiomorphs” from eleven species of the Gibberella fujikuroi species complex were sequenced. Molecular evolution of the MAT loci from these heterothallic (self-sterile) species was compared with that of the MAT loci from nine homothallic (self-fertile) species in the Fusarium graminearum species complex. Although Fusarium has previously been thought to have the same complement of four MAT genes that are found in Neurospora, we found evidence of a novel gene, MAT1-2-3, that may be specific to the Hypocreales. All MAT genes share a similar set of cis-regulatory motifs, although homothallic species might have recruited novel regulatory elements, which could potentially facilitate alternate expression of MAT1-1-1 and MAT1-2-1. Fusarium MAT loci displayed evidence consistent with historical lateral gene-flow. Most notably, the MAT1-1 idiomorph of Fusarium sacchari appears to be unrelated to those of other species in the G. fujikuroi complex. In general, Fusarium MAT genes are highly divergent. Both positive selection and relaxed selective constraint could account for this phenomenon. However, the extent of both recombination and inter-specific gene-flow in the MAT locus also appears to affect the rate of divergence.National Research Foundation (NRF), the DST (Department of Science and Technology)/NRF Centre of Excellence in Tree Health Biotechnology (CTHB), the University of Pretoria, the Tree Protection Cooperative Programme (TPCP)
Ophiostoma denticiliatum sp. nov. and other Ophiostoma species associated with the birch bark beetle in southern Norway
Ophiostomatoid fungi were isolated from Scolytus ratzeburgi infesting Betula pendula and B. pubescens in Norway. Fungi were identified based on morphology, DNA sequence comparison for two gene regions and phylogenetic analyses. The most abundant fungus was Ophiostoma karelicum, suggesting a specific relationship between the fungus, the vector insect and the host tree. Our results suggest that O. karelicum occurs across the geographic range of S. ratzeburgi and its close relatedness to the Dutch elm disease fungi suggests that it could be important if introduced into other parts of the world. Other fungi, only occasionally isolated from S. ratzeburgi, were identified as O. quercus and a novel taxon, described here as O. denticiliatum sp. nov
Acute restraint stress does not alter corticosteroid receptor or 11β-Hydroxysteroid dehydrogenase gene expression at Hypothalamic-Pituitary-Adrenal axis regulatory sites in captive male white-crowned sparrows (Zonotrichia leucophrys gambelii)
Designing and implementing a socioeconomic intervention to enhance TB control: operational evidence from the CRESIPT project in Peru.
BACKGROUND: Cash transfers are key interventions in the World Health Organisation's post-2015 global TB policy. However, evidence guiding TB-specific cash transfer implementation is limited. We designed, implemented and refined a novel TB-specific socioeconomic intervention that included cash transfers, which aimed to support TB prevention and cure in resource-constrained shantytowns in Lima, Peru for: the Community Randomized Evaluation of a Socioeconomic Intervention to Prevent TB (CRESIPT) project. METHODS: Newly-diagnosed TB patients from study-site healthposts were eligible to receive the intervention consisting of economic and social support. Economic support was provided to patient households through cash transfers on meeting the following conditions: screening for TB in household contacts and MDR TB in patients; adhering to TB treatment and chemoprophylaxis; and engaging with CRESIPT social support (household visits and community meetings). To evaluate project acceptability, quantitative and qualitative feedback was collected using a mixed-methods approach during formative activities. Formative activities included consultations, focus group discussions and questionnaires conducted with the project team, project participants, civil society and stakeholders. RESULTS: Over 7 months, 135 randomly-selected patients and their 647 household contacts were recruited from 32 impoverished shantytown communities. Of 1299 potential cash transfers, 964 (74 %) were achieved, 259 (19 %) were not achieved, and 76 (7 %) were yet to be achieved. Of those achieved, 885/964 (92 %) were achieved optimally and 79/964 (8 %) sub-optimally. Key project successes were identified during 135 formative activities and included: strong multi-sectorial collaboration; generation of new evidence for TB-specific cash transfer; and the project being perceived as patient-centred and empowering. Challenges included: participant confidence being eroded through cash transfer delays, hidden account-charges and stigma; access to the initial bank-provider being limited; and conditions requiring participation of all TB-affected household members (e.g. community meetings) being hard to achieve. Refinements were made to improve project acceptability and future impact: the initial bank-provider was changed; conditional and unconditional cash transfers were combined; cash transfer sums were increased to a locally-appropriate, evidence-based amount; and cash transfer size varied according to patient household size to maximally reduce mitigation of TB-related costs and be more responsive to household needs. CONCLUSIONS: A novel TB-specific socioeconomic intervention including conditional cash transfers has been designed, implemented, refined and is ready for impact assessment, including by the CRESIPT project. The lessons learnt during this research will inform policy-makers and decision-makers for future implementation of related interventions
The stress response is attenuated during inclement weather in parental, but not in pre-parental, Lapland longspurs (Calcarius lapponicus) breeding in the Low Arctic
AbstractBirds breeding at high latitudes can be faced with extreme weather events throughout the breeding season. In response to environmental perturbations, vertebrates activate the hypothalamic-pituitary-adrenal (HPA) axis and synthesize corticosterone, which promotes changes in behavior and physiology to help the animal survive. The parental care hypothesis suggests that the HPA axis activity should be downregulated during the parental stage of breeding to prevent nest abandonment. However, it is unknown what happens to HPA axis activity in response to severe weather at the transition from the pre-parental to parental stages of breeding. We sampled baseline corticosterone levels and the time course of corticosterone elevation over 60min of restraint stress and assessed body condition and fat stores in Lapland longspurs (Calcarius lapponicus) breeding in the Low Arctic in the presence and absence of snowstorms. The results showed that during the pre-parental stage, HPA axis activity was up-regulated in response to snowstorms, with corticosterone levels continuing to increase through 60min of restraint. However, once birds were parental, HPA axis activity was unaffected by snowstorms and levels peaked at 10min. Fat levels and body condition did not change in response to snowstorms but fat levels declined in males during the pre-parental stage. These data suggest that the parental care hypothesis can be applied to severe storm events; parental birds restrained the activity of the HPA axis, likely to focus on the reproductive effort that is already underway, while pre-parental birds greatly upregulated HPA axis activity in response to snowstorms to maximize self-preservation
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