QTL mapping of a natural genetic polymorphism for long-term parasite persistence in Daphnia populations

Parasitology ◽  
2017 ◽  
Vol 144 (13) ◽  
pp. 1686-1694 ◽  
Author(s):  
MICHELLE KREBS ◽  
JARKKO ROUTTU ◽  
DIETER EBERT
Keyword(s):  
Geographic Distribution ◽  
Quantitative Trait ◽  
Evolutionary Ecology ◽  
Genetic Trait ◽  
Geographic Ranges ◽  
Northern European ◽  
European Genotype ◽  
Peculiar Case ◽  
Quantitative Genetic Trait

SUMMARYKnowing the determinants of the geographic ranges of parasites is important for understanding their evolutionary ecology, epidemiology and their potential to expand their range. Here we explore the determinants of geographic range in the peculiar case of a parasite species – the microsporidian Hamiltosporidium tvaerminnensis – that has a limited geographic distribution in a wide-spread host – Daphnia magna. We conducted a quantitative trait loci (QTLs) analysis with monoclonal F2D. magna populations originating from a cross between a susceptible northern European genotype and a resistant central European genotype. Contrary to our expectations, long-term persistence turned out to be a quantitative trait across the F2 offspring. Evidence for two QTLs, one epistatic interaction and for further minor QTL was found. This finding contrasts markedly with the previously described bimodal pattern for long-term parasite persistence in natural host genotypes across Europe and leaves open the question of how a quantitative genetic trait could determine the disjunct geographic distribution of the parasite across Europe.

scholarly journals Shedding New Light on Mountainous Forest Growth: A Cross-Scale Evaluation of the Effects of Topographic Illumination Correction on 25 Years of Forest Cover Change across Nepal

2021 ◽  
Vol 13 (11) ◽  
pp. 2131
Author(s):  
Jamon Van Den Hoek ◽  
Alexander C. Smith ◽  
Kaspar Hurni ◽  
Sumeet Saksena ◽  
Jefferson Fox
Keyword(s):  
Remote Sensing ◽  
Geographic Distribution ◽  
Classification Accuracy ◽  
Forest Cover ◽  
Forest Growth ◽  
Forest Cover Change ◽  
Scale Evaluation ◽  
Beneficial Effects ◽  
Affect Detection

Accurate remote sensing of mountainous forest cover change is important for myriad social and ecological reasons, but is challenged by topographic and illumination conditions that can affect detection of forests. Several topographic illumination correction (TIC) approaches have been developed to mitigate these effects, but existing research has focused mostly on whether TIC improves forest cover classification accuracy and has usually found only marginal gains. However, the beneficial effects of TIC may go well beyond accuracy since TIC promises to improve detection of low illuminated forest cover and thereby normalize measurements of the amount, geographic distribution, and rate of forest cover change regardless of illumination. To assess the effects of TIC on the extent and geographic distribution of forest cover change, in addition to classification accuracy, we mapped forest cover across mountainous Nepal using a 25-year (1992–2016) gap-filled Landsat time series in two ways—with and without TIC (i.e., nonTIC)—and classified annual forest cover using a Random Forest classifier. We found that TIC modestly increased classifier accuracy and produced more conservative estimates of net forest cover change across Nepal (−5.2% from 1992–2016) TIC. TIC also resulted in a more even distribution of forest cover gain across Nepal with 3–5% more net gain and 4–6% more regenerated forest in the least illuminated regions. These results show that TIC helped to normalize forest cover change across varying illumination conditions with particular benefits for detecting mountainous forest cover gain. We encourage the use of TIC for satellite remote sensing detection of long-term mountainous forest cover change.

scholarly journals Geographic Distribution and Phylogeny of Soricine Shrew-Borne Seewis Virus and Altai Virus in Russia

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1286
Author(s):  
Liudmila N. Yashina ◽  
Sergey A. Abramov ◽  
Alexander V. Zhigalin ◽  
Natalia A. Smetannikova ◽  
Tamara A. Dupal ◽  
...  
Keyword(s):  
Geographic Distribution ◽  
Genomic Sequence ◽  
Common Shrew ◽  
The United States ◽  
Eastern Siberia ◽  
Geographic Ranges ◽  
Lena River ◽  
Far Eastern Russia ◽  
Far Eastern ◽  
Eastern Russia

The discovery of genetically distinct hantaviruses (family Hantaviridae) in multiple species of shrews, moles and bats has revealed a complex evolutionary history involving cross-species transmission. Seewis virus (SWSV) is widely distributed throughout the geographic ranges of its soricid hosts, including the Eurasian common shrew (Sorex araneus), tundra shrew (Sorex tundrensis) and Siberian large-toothed shrew (Sorex daphaenodon), suggesting host sharing. In addition, genetic variants of SWSV, previously named Artybash virus (ARTV) and Amga virus, have been detected in the Laxmann’s shrew (Sorex caecutiens). Here, we describe the geographic distribution and phylogeny of SWSV and Altai virus (ALTV) in Asian Russia. The complete genomic sequence analysis showed that ALTV, also harbored by the Eurasian common shrew, is a new hantavirus species, distantly related to SWSV. Moreover, Lena River virus (LENV) appears to be a distinct hantavirus species, harbored by Laxmann’s shrews and flat-skulled shrews (Sorex roboratus) in Eastern Siberia and far-eastern Russia. Another ALTV-related virus, which is more closely related to Camp Ripley virus from the United States, has been identified in the Eurasian least shrew (Sorex minutissimus) from far-eastern Russia. Two highly divergent viruses, ALTV and SWSV co-circulate among common shrews in Western Siberia, while LENV and the ARTV variant of SWSV co-circulate among Laxmann’s shrews in Eastern Siberia and far-eastern Russia. ALTV and ALTV-related viruses appear to belong to the Mobatvirus genus, while SWSV is a member of the Orthohantavirus genus. These findings suggest that ALTV and ALTV-related hantaviruses might have emerged from ancient cross-species transmission with subsequent diversification within Sorex shrews in Eurasia.

Healthcare in Rural Manitoba: Resources and Related Issues of Access

1989 ◽  
Vol 2 (2) ◽  
pp. 6-11
Author(s):  
John M. Horne
Keyword(s):  
Rural Communities ◽  
Geographic Distribution ◽  
Long Term Care ◽  
Efficient Allocation ◽  
Allocation Of Resources ◽  
Term Care ◽  
Healthcare Resources ◽  
Hospital Medical ◽  
Publicly Insured

This paper reviews the existing allocation of healthcare resources to and within rural Manitoba. The geographic distribution of hospital, medical and long-term care resources is described and discussed in relation to widely held perceptions of continuing problems in access to publicly insured care among residents of rural communities. Opportunities for more effective and efficient allocation of resources are identified, including various arrangements for sharing both facilities and personnel between communities.

Idiopathic anaphylaxis: Diagnosis and management

2021 ◽  
Vol 42 (6) ◽  
pp. 481-488 ◽  
Author(s):  
Alyssa G. Burrows ◽  
Anne K. Ellis
Keyword(s):  
Food Allergy ◽  
Immunoglobulin E ◽  
Treatment Options ◽  
Serum Tryptase ◽  
Genetic Trait ◽  
Baseline Serum ◽  
Diagnostic Technologies ◽  
Term Management ◽  
Idiopathic Anaphylaxis

Introduction: Idiopathic anaphylaxis (IA) is a diagnosis of exclusion and is based on the inability to identify a causal relationship between a trigger and an anaphylactic event, despite a detailed patient history and careful diagnostic assessment. The prevalence of IA among the subset of people who experienced anaphylaxis is challenging to estimate and varies widely, from 10 to 60%; most commonly noted is ∼20% in the adult anaphylactic population. Comorbid atopic conditions, such as food allergy, allergic rhinitis, and asthma, are present in up to 48% of patients with IA. Improved diagnostic technologies and an increased understanding of conditions that manifest with symptoms associated with anaphylaxis have improved the ability to determine a more accurate diagnosis for patients who may have been initially diagnosed with IA. Methods: Literature search was conducted on PubMed, Google Scholar and Embase. Results: Galactose-α-1,3-galactose (α-gal) allergy, mast cell disorders, and hereditary a-tryptasemia are a few differential diagnoses that should be considered in patients with IA. Unlike food allergy, when anaphylaxis occurs within minutes to 2 hours after allergen consumption, α-gal allergy is a 3‐6-hour delayed immunoglobulin E‐mediated anaphylactic reaction to a carbohydrate epitope found in red meat (e.g., beef, lamb, pork). The more recently described hereditary α-tryptasemia is an inherited autosomal dominant genetic trait caused by increased germline copies of tryptase human gene alpha-beta 1 (TPSAB1), which encodes α tryptase and is associated with elevated baseline serum tryptase. Acute management of IA consists of carrying an epinephrine autoinjector to be administered immediately at the first signs of anaphylaxis. Long-term management for IA with antihistamines and other agents aims to potentially reduce the frequency and severity of the anaphylactic reactions, although the evidence is limited. Biologics are potentially steroid-sparing for patients with IA; however, more research on IA therapies is needed. Conclusion: The lack of diagnostic criteria, finite treatment options, and intricacies of making a differential diagnosis make IA challenging for patients and clinicians to manage.

Conventional and isotopic determinations of shorebird diets at an inland stopover: the importance of invertebrates and Potamogeton pectinatus tubers

1996 ◽  
Vol 74 (6) ◽  
pp. 1057-1068 ◽  
Author(s):  
Stuart A. Alexander ◽  
Keith A. Hobson ◽  
Cheri L. Gratto-Trevor ◽  
Antony W. Diamond
Keyword(s):  
Stable Isotope ◽  
Potamogeton Pectinatus ◽  
Gut Content Analysis ◽  
Gut Content ◽  
Geographic Ranges ◽  
Isotope Technique ◽  
Wetland Complex ◽  
Limnodromus Scolopaceus ◽  
Stable Isotope Technique

We used gut-content and stable-isotope techniques to determine diets of shorebirds staging at a prairie wetland complex. Stable-isotope ratios for carbon (13C/12C) and nitrogen (15N/14N) varied greatly within and among prey types and shorebirds, depending on location within the complex. Both dietary techniques suggested that Long-billed Dowitchers (Limnodromus scolopaceus) and Stilt Sandpipers (Calidris himantopus) ate mostly invertebrates, whereas Hudsonian (Limosa haemastica) and Marbled godwits (Limosa fedoa) ate mainly Potamogeton pectinatus tubers. In comparison, the stable-isotope technique indicated that godwits, especially juvenile Marbled Godwits, ate more invertebrates than is indicated by the gut-content analysis. The discrepancies between methods reflect the potential for bias in the application of these techniques. Researchers using stable isotopes to assess migratory shorebird diets should be aware of possible complications arising from isotopic variability within prey types, even over small geographic ranges. High isotopic variability at inland agro-wetland complexes might preclude reliable isotopic assessment of shorebird diets, especially long term. Rhizivory in godwits may be more common than is generally recognized, especially at inland stopovers during autumn migration in both North America and Eurasia, and should be factored into conservation initiatives for these species.

Designation of a neotype for the Brazilian porcupine, Coendou prehensilis (Linnaeus, 1758)

Zootaxa ◽  
2011 ◽  
Vol 2791 (1) ◽  
pp. 30 ◽  
Author(s):  
YURI L. R. LEITE ◽  
VILACIO CALDARA JÚNIOR ◽  
ANA CAROLINA LOSS ◽  
LEONORA PIRES COSTA ◽  
ÉVERTON R. A. MELO ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Geographic Distribution ◽  
Related Species ◽  
Taxonomic Revision ◽  
Type Specimen ◽  
Northeastern Brazil ◽  
Closely Related Species ◽  
Geographic Ranges ◽  
Central Brazil ◽  
Shed Light

The Brazilian porcupine was one of several species described and illustrated by the 17 th -century naturalist Georg Marcgrave, whose text was among the primary references upon which Linnaeus based his Hystrix prehensilis. As currently understood, Coendou prehensilis is a wide-ranging polytypic taxon that has never been revised and may represent a complex of closely related species. Given that no name-bearing type specimen of C. prehensilis is believed to be extant, and in order to avoid ambiguous application of this name, we designate a specimen collected at the type locality in Pernambuco, northeastern Brazil, as the neotype for Hystrix prehensilis Linnaeus. The geographic distribution of mitochondrial DNA haplotypes suggests that specimens from west-central Brazil previously identified as “Coendou prehensilis” belong to a different species, but only a comprehensive taxonomic revision of the genus will shed light on species limits and the geographic ranges of C. prehensilis and other congeneric forms.

scholarly journals Evolutionary Ecology of Prokaryotic Immune Mechanisms

2016 ◽  
Vol 80 (3) ◽  
pp. 745-763 ◽  
Author(s):  
Stineke van Houte ◽  
Angus Buckling ◽  
Edze R. Westra
Keyword(s):  
Mechanism Of Action ◽  
Evolutionary Ecology ◽  
Costs And Benefits ◽  
Defense Strategies ◽  
Ecological Conditions ◽  
Genetic Elements ◽  
Immune Mechanisms ◽  
Resistance Strategies ◽  
Short And Long Term

SUMMARYBacteria have a range of distinct immune strategies that provide protection against bacteriophage (phage) infections. While much has been learned about the mechanism of action of these defense strategies, it is less clear why such diversity in defense strategies has evolved. In this review, we discuss the short- and long-term costs and benefits of the different resistance strategies and, hence, the ecological conditions that are likely to favor the different strategies alone and in combination. Finally, we discuss some of the broader consequences, beyond resistance to phage and other genetic elements, resulting from the operation of different immune strategies.

The Geographical Distribution of Psychiatrists in Canada: Unmet Needs and Remedial Strategies

1993 ◽  
Vol 38 (3) ◽  
pp. 212-216 ◽  
Author(s):  
N. El-Guebaly ◽  
E. Kingstone ◽  
Q. Rae-Grant ◽  
I. Fyfe
Keyword(s):  
Geographic Distribution ◽  
Financial Incentives ◽  
Community Support ◽  
Manpower Planning ◽  
Short Term ◽  
Professional Norms ◽  
Tiered System ◽  
Remedial Strategies

Many efforts are underway to rationalize the process of manpower planning in psychiatry. A wide variation in the geographic distribution of psychiatrists remains. A multidimensional assessment of the needs of a population is recommended, based on the epidemiology of mental disorders, professional and institutional needs, consumer estimates, and the requirements of subgroups. Counting the number of vacant positions for psychiatrists can be misleading. Professional norms for the optimal access of a population to psychiatric services and standards for the quantity and/or quality of services provided need to be developed. Potential outcome measures are suggested, along with a three-tiered system of estimating geographic needs. Deterrent factors to an optimal geographic distribution of most professionals are reviewed, along with factors specific to our residency training programs. In the short term, the benefits and limitations of recruiting foreign-trained psychiatrists are compared with those of recruiting Canadian specialists. Complementary long term strategies include the provision of financial incentives, optimal working conditions, relevant training and maintenance of competence issues, and community support.

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