423 research outputs found
cis-Jasmone Elicits Aphid-Induced Stress Signalling in Potatoes
Elicitation of plant defense signaling that results in altered emission of volatile organic compounds (VOCs) offers opportunities for protecting plants against arthropod pests. In this study, we treated potato, Solanum tuberosum L., with the plant defense elicitor cis-jasmone (CJ), which induces the emission of defense VOCs and thus affects the behavior of herbivores. Using chemical analysis, electrophysiological and behavioral assays with the potato-feeding aphid Macrosiphum euphorbiae, we showed that CJ treatment substantially increased the emission of defense VOCs from potatoes compared to no treatment. Coupled GC-electroantennogram (GC-EAG) recordings from the antennae of M. euphorbiae showed robust responses to 14 compounds present in induced VOCs, suggesting their behavioral role in potato/aphid interactions. Plants treated with CJ and then challenged with M. euphorbiae were most repellent to alate M. euphorbiae. Principal component analysis (PCA) of VOC collections suggested that (E)-2-hexenal, (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene (TMTT), (E)-β-farnesene, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), methyl salicylate (MeSA), CJ, and methyl benzoate (MeBA) were the main VOCs contributing to aphid behavioral responses, and that production of TMTT, (E)-β-farnesene, CJ, and DMNT correlated most strongly with aphid repellency. Our findings confirm that CJ can enhance potato defense against aphids by inducing production of VOCs involved in aphid-induced signalling
Penetrance and expressivity of mitochondrial variants in a large clinically unselected population
\ua9 The Author(s) 2023. Published by Oxford University Press. Whole genome sequencing (WGS) from large clinically unselected cohorts provides a unique opportunity to assess the penetrance and expressivity of rare and/or known pathogenic mitochondrial variants in population. Using WGS from 179 862 clinically unselected individuals from the UK Biobank, we performed extensive single and rare variant aggregation association analyses of 15 881 mtDNA variants and 73 known pathogenic variants with 15 mitochondrial disease-relevant phenotypes. We identified 12 homoplasmic and one heteroplasmic variant (m.3243A>G) with genome-wide significant associations in our clinically unselected cohort. Heteroplasmic m.3243A>G (MAF = 0.0002, a known pathogenic variant) was associated with diabetes, deafness and heart failure and 12 homoplasmic variants increased aspartate aminotransferase levels including three low-frequency variants (MAF ~0.002 and beta~0.3 SD). Most pathogenic mitochondrial disease variants (n = 66/74) were rare in the population (<1:9000). Aggregated or single variant analysis of pathogenic variants showed low penetrance in unselected settings for the relevant phenotypes, except m.3243A>G. Multi-system disease risk and penetrance of diabetes, deafness and heart failure greatly increased with m.3243A>G level ≥ 10%. The odds ratio of these traits increased from 5.61, 12.3 and 10.1 to 25.1, 55.0 and 39.5, respectively. Diabetes risk with m.3243A>G was further influenced by type 2 diabetes genetic risk. Our study of mitochondrial variation in a large-unselected population identified novel associations and demonstrated that pathogenic mitochondrial variants have lower penetrance in clinically unselected settings. m.3243A>G was an exception at higher heteroplasmy showing a significant impact on health making it a good candidate for incidental reporting
MRS-guided HDR brachytherapy boost to the dominant intraprostatic lesion in high risk localised prostate cancer
BACKGROUND: It is known that the vast majority of prostate cancers are multifocal. However radical radiotherapy historically treats the whole gland rather than individual cancer foci.Magnetic resonance spectroscopy (MRS) can be used to non-invasively locate individual cancerous tumours in prostate. Thus an intentionally non-uniform dose distribution treating the dominant intraprostatic lesion to different dose levels than the remaining prostate can be delivered ensuring the maximum achievable tumour control probability.The aim of this study is to evaluate, using radiobiological means, the feasibility of a MRS-guided high dose rate (HDR) brachytherapy boost to the dominant lesion.\ud
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METHODS: Computed tomography and MR/MRS were performed for treatment planning of a high risk localised prostate cancer. Both were done without endorectal coil, which distorts shape of prostate during the exams.Three treatment plans were compared:- external beam radiation therapy (EBRT) only- combination of EBRT and HDR brachytherapy- combination of EBRT and HDR brachytherapy with a synchronous integrated boost to the dominant lesionThe criteria of plan comparison were: the minimum, maximum and average doses to the targets and organs at risk; dose volume histograms; biologically effective doses for organs at risk and tumour control probability for the target volumes consisting of the dominant lesion as detected by MR/MRS and the remaining prostate volume.\ud
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RESULTS: Inclusion of MRS information on the location of dominant lesion allows a safe increase of the dose to the dominant lesion while dose to the remaining target can be even substantially decreased keeping the same, high tumour control probability. At the same time an improved urethra sparing was achieved comparing to the treatment plan using a combination of EBRT and uniform HDR brachytherapy.\ud
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CONCLUSIONS: MRS-guided HDR brachytherapy boost to dominant lesion has the potential to spare the normal tissue, especially urethra, while keeping the tumour control probability high
Penetrance and expressivity of mitochondrial variants in a large clinically unselected population
This is the final version. Available on open access from Oxford University Press via the DOI in this recordData availability:
The data supporting the findings of this study are available within the article and its Supplementary Data files. Additional information for reproducing the results described in the article is available upon reasonable request and subject to a data use agreement. The UK Biobank dataset is available from https://biobank.ctsu.ox.ac.ukBACKGROUND: Whole genome sequencing (WGS) from large clinically unselected cohorts provides a unique opportunity to assess the penetrance and expressivity of rare and/or known pathogenic mitochondrial variants in population. METHOD: Using WGS from 179 862 clinically unselected individuals from the UK Biobank, we performed extensive single and rare variant aggregation association analyses of 15 881 mtDNA variants and 73 known pathogenic variants with 15 mitochondrial disease-relevant phenotypes. RESULTS: We identified 12 homoplasmic and one heteroplasmic variant (m.3243A>G) with genome-wide significant associations in our clinically unselected cohort. Heteroplasmic m.3243A>G (MAF = 0.0002, a known pathogenic variant) was associated with diabetes, deafness and heart failure and 12 homoplasmic variants increased aspartate aminotransferase levels including three low-frequency variants (MAF ~0.002 and beta~0.3 SD). Most pathogenic mitochondrial disease variants (n = 66/74) were rare in the population (G. Multi-system disease risk and penetrance of diabetes, deafness and heart failure greatly increased with m.3243A>G level ≥ 10%. The odds ratio of these traits increased from 5.61, 12.3 and 10.1 to 25.1, 55.0 and 39.5 respectively. Diabetes risk with m.3243A>G was further influenced by type 2 diabetes genetic risk. CONCLUSION: Our study of mitochondrial variation in a large-unselected population identified novel associations and demonstrated that pathogenic mitochondrial variants have lower penetrance in clinically unselected settings. m.3243A>G was an exception at higher heteroplasmy showing a significant impact on health making it a good candidate for incidental reporting.Diabetes UKMedical Research Council (MRC)Wellcome TrustNational Institute for Health and Care Research (NIHR
Odour-mediated orientation of beetles is influenced by age, sex and morph
The behaviour of insects is dictated by a combination of factors and may vary considerably between individuals, but small insects are often considered en masse and thus these differences can be overlooked. For example, the cowpea bruchid Callosobruchus maculatus F. exists naturally in two adult forms: the active (flight) form for dispersal, and the inactive (flightless), more fecund but shorter-lived form. Given that these morphs show dissimilar biology, it is possible that they differ in odour-mediated orientation and yet studies of this species frequently neglect to distinguish morph type, or are carried out only on the inactive morph. Along with sex and age of individual, adult morph could be an important variable determining the biology of this and similar species, informing studies on evolution, ecology and pest management. We used an olfactometer with motion-tracking to investigate whether the olfactory behaviour and orientation of C. maculatus towards infested and uninfested cowpeas and a plant-derived repellent compound, methyl salicylate, differed between morphs or sexes. We found significant differences between the behaviour of male and female beetles and beetles of different ages, as well as interactive effects of sex, morph and age, in response to both host and repellent odours. This study demonstrates that behavioural experiments on insects should control for sex and age, while also considering differences between adult morphs where present in insect species. This finding has broad implications for fundamental entomological research, particularly when exploring the relationships between physiology, behaviour and evolutionary biology, and the application of crop protection strategies
Prospects for the development of odour baits to control the tsetse flies Glossina tachinoides and G. palpalis s.l.
Field studies were done of the responses of Glossina palpalis palpalis in Côte d'Ivoire, and G. p. gambiensis and G. tachinoides in Burkina Faso, to odours from humans, cattle and pigs. Responses were measured either by baiting (1.) biconical traps or (2.) electrocuting black targets with natural host odours. The catch of G. tachinoides from traps was significantly enhanced (~5×) by odour from cattle but not humans. In contrast, catches from electric targets showed inconsistent results. For G. p. gambiensis both human and cattle odour increased (>2×) the trap catch significantly but not the catch from electric targets. For G. p. palpalis, odours from pigs and humans increased (~5×) the numbers of tsetse attracted to the vicinity of the odour source but had little effect on landing or trap-entry. For G. tachinoides a blend of POCA (P = 3-n-propylphenol; O = 1-octen-3-ol; C = 4-methylphenol; A = acetone) alone or synthetic cattle odour (acetone, 1-octen-3-ol, 4-methylphenol and 3-n-propylphenol with carbon dioxide) consistently caught more tsetse than natural cattle odour. For G. p. gambiensis, POCA consistently increased catches from both traps and targets. For G. p. palpalis, doses of carbon dioxide similar to those produced by a host resulted in similar increases in attraction. Baiting traps with super-normal (~500 mg/h) doses of acetone also consistently produced significant but slight (~1.6×) increases in catches of male flies. The results suggest that odour-baited traps and insecticide-treated targets could assist the AU-Pan African Tsetse and Trypanosomiasis Eradication Campaign (PATTEC) in its current efforts to monitor and control Palpalis group tsetse in West Africa. For all three species, only ~50% of the flies attracted to the vicinity of the trap were actually caught by it, suggesting that better traps might be developed by an analysis of the visual responses and identification of any semiochemicals involved in short-range interaction
Does Community Context Have an Important Impact on Divorce Risk? A Fixed-Effects Study of Twenty Norwegian First-Marriage Cohorts
The decision to divorce may be affected by the characteristics of the local community. Community characteristics may be barriers to divorce, or they may increase the attractiveness of divorcing (e.g., access to a good remarriage market), but our knowledge of such influences is sparse. This study examines two such community-level factors: socio-economic conditions and the local marriage market. In this study, discrete-time hazard models with community-level fixed effects are estimated using register-based data on Norwegian first marriages during the period from 1980 to 1999, with longitudinal information on both the community and couple levels (N = 283,493). The results show that there are important community-level influences on couples’ divorce risk, but these change dramatically when fixed effects are introduced
Stages of development and injury patterns in the early years: a population-based analysis
BACKGROUND: In Canada, there are many formal public health programs under development that aim to prevent injuries in the early years (e.g. 0–6). There are paradoxically no population-based studies that have examined patterns of injury by developmental stage among these young children. This represents a gap in the Canadian biomedical literature. The current population-based analysis explores external causes and consequences of injuries experienced by young children who present to the emergency department for assessment and treatment. This provides objective evidence about prevention priorities to be considered in anticipatory counseling and public health planning. METHODS: Four complete years of data (1999–2002; n = 5876 cases) were reviewed from the Kingston sites of the Canadian Hospitals Injury Reporting and Prevention Program (CHIRPP), an ongoing injury surveillance initiative. Epidemiological analyses were used to characterize injury patterns within and across age groups (0–6 years) that corresponded to normative developmental stages. RESULTS: The average annual rate of emergency department-attended childhood injury was 107 per 1000 (95% CI 91–123), with boys experiencing higher annual rates of injury than girls (122 vs. 91 per 1000; p < 0.05). External causes of injury changed substantially by developmental stage. This lead to the identification of four prevention priorities surrounding 1) the optimization of supervision; 2) limiting access to hazards; 3) protection from heights; and 4) anticipation of risks. CONCLUSION: This population-based injury surveillance analysis provides a strong evidence-base to inform and enhance anticipatory counseling and other public health efforts aimed at the prevention of childhood injury during the early years
Field Testing of Different Chemical Combinations as Odour Baits for Trapping Wild Mosquitoes in The Gambia
Odour baited traps have potential use in population surveillance of insect vectors of disease, and in some cases for vector population reduction. Established attractants for human host-seeking mosquitoes include a combination of CO2 with L-lactic acid and ammonia, on top of which additional candidate compounds are being tested. In this field study in rural Gambia, using Latin square experiments with thorough randomization and replication, we tested nine different leading candidate combinations of chemical odorants for attractiveness to wild mosquitoes including anthropophilic malaria vectors, using modified Mosquito Magnet-X (MM-X) counterflow traps outside experimental huts containing male human sleepers. Highest catches of female mosquitoes, particularly of An. gambiae s.l. and Mansonia species, were obtained by incorporation of tetradecanoic acid. As additional carboxylic acids did not increase the trap catches further, this ‘reference blend’ (tetradecanoic acid with L-lactic acid, ammonia and CO2) was used in subsequent experiments. MM-X traps with this blend caught similar numbers of An. gambiae s.l. and slightly more Mansonia and Culex mosquitoes than a standard CDC light trap, and these numbers were not significantly affected by the presence or absence of human sleepers in the huts. Experiments with CO2 produced from overnight yeast cultures showed that this organic source was effective in enabling trap attractiveness for all mosquito species, although at a slightly lower efficiency than obtained with use of CO2 gas cylinders. Although further studies are needed to discover additional chemicals that increase attractiveness, as well as to optimise trap design and CO2 source for broader practical use, the odour-baited traps described here are safe and effective for sampling host-seeking mosquitoes outdoors and can be incorporated into studies of malaria vector ecology
Young off-axis volcanism along the ultraslow-spreading Southwest Indian Ridge
Author Posting. © The Authors, 2010. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in Nature Geoscience 3 (2010): 286-292, doi:10.1038/ngeo824.Mid-ocean ridge crustal accretion occurs continuously at all spreading rates
through a combination of magmatic and tectonic processes. Fast to slow spreading
ridges are largely built by adding magma to narrowly focused neovolcanic zones. In
contrast, ultraslow spreading ridge construction significantly relies on tectonic
accretion, which is characterized by thin volcanic crust, emplacement of mantle
peridotite directly to the seafloor, and unique seafloor fabrics with variable
segmentation patterns. While advances in remote imaging have enhanced our
observational understanding of crustal accretion at all spreading rates, temporal
information is required in order to quantitatively understand mid-ocean ridge
construction. However, temporal information does not exist for ultraslow spreading
environments. Here, we utilize U-series eruption ages to investigate crustal
accretion at an ultraslow spreading ridge for the first time. Unexpectedly young
eruption ages throughout the Southwest Indian ridge rift valley indicate that
neovolcanic activity is not confined to the spreading axis, and that magmatic crustal
accretion occurs over a wider zone than at faster spreading ridges. These
observations not only suggest that crustal accretion at ultraslow spreading ridges is
distinct from faster spreading ridges, but also that the magma transport
mechanisms may differ as a function of spreading rate.This work was supported by
the following NSF grants: NSF-OCE 0137325; NSF-OCE 060383800; and NSF-OCE
062705300
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