66 research outputs found
Billbug (Sphenophorus spp.) chemical ecology and seasonal biology in Indiana turfgrass
Billbugs (Coleoptera: Curculionoidea: Sphenophorus) are serious pests of managed turfgrass across North America. Damage symptoms are most visible during stressful periods of the growing season and are commonly confused with disease, drought, or nutrient deficiency. Billbugs are frequently a perennial problem and when misdiagnosed, damage often results in seriously degraded stands of turfgrass that are easily encroached by weeds. Presently, management of billbugs relies heavily on chemical insecticides. Even then, the nationwide assemblage of multiple sympatric billbug species and the cryptic nature of the damaging larval stage makes management of these insects challenging. A better understanding of billbug biology and behavior could improve the efficacy of insecticide inputs and provide a basis for the development of alternative, non-pesticide management techniques that are aligned with integrated pest management (IPM). This thesis focused on characterizing the billbug species composition in Indiana and clarifying the seasonal phenology of one particularly problematic species, S. venatus. To accomplish this, I examined the utility of molecular techniques to identify the otherwise cryptic larval stage of several sympatric, turf-inhabiting billbug species. I also explored the potential for S. venatus to use two forms of chemoreception: recognition of volatile organic compounds and cuticular wax components.
Weekly monitoring of pitfall traps revealed four sympatric billbug species in Indiana: S. venatus, S. parvulus, S. minimus, and S. inaequalis. Further investigation on the seasonal biology of S. venatus revealed two overlapping cohorts in Indiana and molecular confirmation of overwintering S. venatus larvae through examination of three genetic loci (CO1, 18S, and ITS2). In y-tube olfactometer bioassays, S. venatus males were attracted to the combination of conspecifics and host-plants as well as host-plants alone. S. venatus females were attracted to the combination of male conspecifics and host plant material and male conspecifics alone. These findings suggest S. venatus males are predominantly influenced by host-plant volatiles while females likely respond to a male-produced volatile pheromone. Coupled gas chromatography-mass spectrometry (GC-MS) analysis of S. venatus and S. parvulus whole-body cuticular extracts revealed a series of aliphatic hydrocarbons with qualitative and quantitative interspecific differences, as well as intraspecific quantitative differences between males and females. These differences in cuticular hydrocarbon profiles could serve as critical mate-recognition cues among sympatric Sphenophorus species, a hypothesis that remains to be tested.
By clarifying the seasonal phenology of S. venatus, results provide a foundation for improved insecticide selection and application timing in the Midwestern U.S. for this pest. Furthermore, findings demonstrate that a DNA-based larval identification tool could be useful for clarifying the seasonal phenology of sympatric billbug species with morphologically indistinguishable larval stages. Findings also support the idea that volatile and contact semiochemicals could potentially be used for the development of improved billbug monitoring techniques and sustainable mating disruption strategies
Citizen science data reveal regional heterogeneity in phenological response to climate in the large milkweed bug,
Regional populations of geographically widespread species may respond to differ- ent environmental factors across the species\u27 range, generating divergent effects of climate change on life-history phenology. Using thousands of citizen science obser- vations extracted from iNaturalist and associated with corresponding temperature, precipitation, elevation, and daylength information, we examined the drivers of adult mating and of nymphal phenology, development, and group size for populations of the large milkweed bug, Oncopeltus fasciatus, in different ecoregions. Research-grade iNaturalist images were correctly identified 98.3% of the time and yielded more than 3000 observations of nymphal groups and 1000 observations of mating adults span- ning 18 years. Mating phenology showed distinct regional patterns, ranging from year-round mating in California to temporally restricted mating in the Great Lakes Northeastern Coast ecoregion. Relative temperature increases of 1°C for a given daylength expanded the mating season by more than a week in western ecoregions. While increases in relative temperature delayed mating phenology in all ecoregions, greater winter precipitation advanced mating in the California ecoregion. In the east- ern ecoregions, nymphal phenology was delayed by increases in summer rainfall but was advanced by relative temperature increases, whereas in western regions, relative temperature increases delayed nymphal phenology. Furthermore, accumulated grow- ing degree days (AGDD) was a poor predictor of developmental progression, as we found a positive but weak correlation between AGDD and age structure only for the Appalachian Southeast North America and the Great Lakes Northern Coast ecore- gions. These complex phenological responses of O. fasciatus are just one example of how populations may be differentially susceptible to a diversity of climatic effects; using data across a species\u27 whole distribution is critical for exposing regional varia- tions, especially for species with large, continental-scale ranges. This study demon- strates the potential of photodocumented biodiversity data to aid in the monitoring of life history, host plant–insect interactions, and climate responsiveness
Assessment of intelligibility in dysarthria: development of a Maltese word and phrase list
This paper describes the development of the Maltese Intelligibility Lists (MIL) for the assessment of word and phrase intelligibility in dysarthria. Two main tools were employed: the Frenchay Dysarthria Assessment-2 (FDA), and the Maltese Language Resource Server (MLRS). Three main criteria served as the basis for the construction of the word and phrase lists: frequency of occurrence of Maltese phonemes, word frequency and an analysis of syllable types and structures. The most common 500 words in the MLRS corpus (Korpus Malti v. 3) were broadly transcribed and an analysis of different types of syllables and their frequency of occurrence was carried out. Based on this analysis, the relevant proportion of different syllable types required for the word and phrase lists for Maltese was calculated in line with the number of items present in the FDA-2. With regards to phoneme frequency, the words chosen demonstrate a similar short-vowel and consonant distribution as reported in a previous large-scale study. The MIL consists of 116 words and 50 phrases which are representative of Standard Maltese and can be used in the clinic to assess speech intelligibility in Maltese individuals with dysarthria
Insect chemical ecology: chemically mediated interactions and novel applications in agriculture
Forum PaperInsect chemical ecology (ICE) evolved as a discipline concerned with plant–insect interactions, and also with a strong
focus on intraspecific pheromone-mediated communication. Progress in this field has rendered a more complete picture of
how insects exploit chemical information in their surroundings in order to survive and navigate their world successfully.
Simultaneously, this progress has prompted new research questions about the evolution of insect chemosensation and related
ecological adaptations, molecular mechanisms that mediate commonly observed behaviors, and the consequences of chemically
mediated interactions in different ecosystems. Themed meetings, workshops, and summer schools are ideal platforms
for discussing scientific advancements as well as identifying gaps and challenges within the discipline. From the 11th to the
22nd of June 2018, the 11th annual PhD course in ICE was held at the Swedish University of Agricultural Sciences (SLU)
Alnarp, Sweden. The course was made up of 35 student participants from 22 nationalities (Fig. 1a) as well as 32 lecturers.
Lectures and laboratory demonstrations were supported by literature seminars, and four broad research areas were covered:
(1) multitrophic interactions and plant defenses, (2) chemical communication focusing on odor sensing, processing, and
behavior, (3) disease vectors, and (4) applied aspects of basic ICE research in agriculture. This particular article contains a
summary and brief synthesis of these main emergent themes and discussions from the ICE 2018 course. In addition, we also
provide suggestions on teaching the next generation of ICE scientists, especially during unprecedented global situationsinfo:eu-repo/semantics/publishedVersio
Continental slope and rise geomorphology seaward of the Totten Glacier, East Antarctica (112°E-122°E)
The continental slope and rise seaward of the Totten Glacier and the Sabrina Coast, East Antarctica features
continental margin depositional systems with high sediment input and consistent along-slope current activity.
Understanding their genesis is a necessary step in interpreting the paleoenvironmental records they contain.
Geomorphic mapping using a systematic multibeam survey shows variations in the roles of downslope and along
slope sediment transport influenced by broad-scale topography and oceanography. The study area contains two
areas with distinct geomorphology. Canyons in the eastern part of the area have concave thalwegs, are linked to
the shelf edge and upper slope and show signs of erosion and deposition along their beds suggesting cycles of
activity controlled by climate cycles. Ridges between these canyons are asymmetric with crests close to the west
bank of adjacent canyons and are mostly formed by westward advection of fine sediment lofted from turbidity
currents and deposition of hemipelagic sediment. They can be thought of as giant levee deposits. The ridges in
the western part of the area have more gently sloping eastern flanks and rise to shallower depths than those in
the east. The major canyon in the western part of the area is unusual in having a convex thalweg; it is likely fed
predominantly by mass movement from the flanks of the adjacent ridges with less sediment input from the shelf
edge. The western ridges formed by accretion of suspended sediment moving along the margin as a broad plume
in response to local oceanography supplemented with detritus originating from the Totten Glacier. This contrasts
with interpretations of similar ridges described from other parts of Antarctica which emphasise sediment input
from canyons immediately up-current. The overall geomorphology of the Sabrina Coast slope is part of a continuum of mixed contourite-turbidite systems identified on glaciated margins.Australian Government
4333Australian Research Council
DP170100557Italian Programma Nazionale di Richerch in Antartide (PNRA)Spanish Government
CTM2014-60451-C2-1-P
CTM2017-89711-C2-1-
Meta-analysis of breast cancer mortality benefit and overdiagnosis adjusted for adherence: improving information on the effects of attending screening mammography
Background: Women require information about the impact of regularly attending screening mammography on breast cancer mortality and overdiagnosis to make informed decisions. To provide this information we aimed to meta-analyse randomised controlled trials adjusted for adherence to the trial protocol. Methods: Nine screening mammography trials used in the Independent UK Breast Screening Report were selected. Extending an existing approach to adjust intention-to-treat (ITT) estimates for less than 100% adherence rates, we conducted a random-effects meta-analysis. This produced a combined deattenuated prevented fraction and a combined deattenuated percentage risk of overdiagnosis. Results: In women aged 39–75 years invited to screen, the prevented fraction of breast cancer mortality at 13-year follow-up was 0.22 (95% CI 0.15–0.28) and it increased to 0.30 (95% CI 0.18–0.42) with deattenuation. In women aged 40–69 years invited to screen, the ITT percentage risk of overdiagnosis during the screening period was 19.0% (95% CI 15.2–22.7%), deattenuation increased this to 29.7% (95% CI 17.8–41.5%). Conclusions: Adjustment for nonadherence increased the size of the mortality benefit and risk of overdiagnosis by up to 50%. These estimates are more appropriate when developing quantitative information to support individual decisions about attending screening mammography
Genomewide association study for onset age in Parkinson disease
<p>Abstract</p> <p>Background</p> <p>Age at onset in Parkinson disease (PD) is a highly heritable quantitative trait for which a significant genetic influence is supported by multiple segregation analyses. Because genes associated with onset age may represent invaluable therapeutic targets to delay the disease, we sought to identify such genetic modifiers using a genomewide association study in familial PD. There have been previous genomewide association studies (GWAS) to identify genes influencing PD susceptibility, but this is the first to identify genes contributing to the variation in onset age.</p> <p>Methods</p> <p>Initial analyses were performed using genotypes generated with the Illumina HumanCNV370Duo array in a sample of 857 unrelated, familial PD cases. Subsequently, a meta-analysis of imputed SNPs was performed combining the familial PD data with that from a previous GWAS of 440 idiopathic PD cases. The SNPs from the meta-analysis with the lowest p-values and consistency in the direction of effect for onset age were then genotyped in a replication sample of 747 idiopathic PD cases from the Parkinson Institute Biobank of Milan, Italy.</p> <p>Results</p> <p>Meta-analysis across the three studies detected consistent association (p < 1 × 10<sup>-5</sup>) with five SNPs, none of which reached genomewide significance. On chromosome 11, the SNP with the lowest p-value (rs10767971; p = 5.4 × 10<sup>-7</sup>) lies between the genes <it>QSER1 </it>and <it>PRRG4</it>. Near the PARK3 linkage region on chromosome 2p13, association was observed with a SNP (rs7577851; p = 8.7 × 10<sup>-6</sup>) which lies in an intron of the <it>AAK1 </it>gene. This gene is closely related to <it>GAK</it>, identified as a possible PD susceptibility gene in the GWAS of the familial PD cases.</p> <p>Conclusion</p> <p>Taken together, these results suggest an influence of genes involved in endocytosis and lysosomal sorting in PD pathogenesis.</p
Common variants at ABCA7, MS4A6A/MS4A4E, EPHA1, CD33 and CD2AP are associated with Alzheimer's disease
We sought to identify new susceptibility loci for Alzheimer's disease through a staged association study (GERAD+) and by testing suggestive loci reported by the Alzheimer's Disease Genetic Consortium (ADGC) in a companion paper. We undertook a combined analysis of four genome-wide association datasets (stage 1) and identified ten newly associated variants with P ≤ 1 × 10−5. We tested these variants for association in an independent sample (stage 2). Three SNPs at two loci replicated and showed evidence for association in a further sample (stage 3). Meta-analyses of all data provided compelling evidence that ABCA7 (rs3764650, meta P = 4.5 × 10−17; including ADGC data, meta P = 5.0 × 10−21) and the MS4A gene cluster (rs610932, meta P = 1.8 × 10−14; including ADGC data, meta P = 1.2 × 10−16) are new Alzheimer's disease susceptibility loci. We also found independent evidence for association for three loci reported by the ADGC, which, when combined, showed genome-wide significance: CD2AP (GERAD+, P = 8.0 × 10−4; including ADGC data, meta P = 8.6 × 10−9), CD33 (GERAD+, P = 2.2 × 10−4; including ADGC data, meta P = 1.6 × 10−9) and EPHA1 (GERAD+, P = 3.4 × 10−4; including ADGC data, meta P = 6.0 × 10−10)
A Genome-Wide Association Study of Diabetic Kidney Disease in Subjects With Type 2 Diabetes
dentification of sequence variants robustly associated with predisposition to diabetic kidney disease (DKD) has the potential to provide insights into the pathophysiological mechanisms responsible. We conducted a genome-wide association study (GWAS) of DKD in type 2 diabetes (T2D) using eight complementary dichotomous and quantitative DKD phenotypes: the principal dichotomous analysis involved 5,717 T2D subjects, 3,345 with DKD. Promising association signals were evaluated in up to 26,827 subjects with T2D (12,710 with DKD). A combined T1D+T2D GWAS was performed using complementary data available for subjects with T1D, which, with replication samples, involved up to 40,340 subjects with diabetes (18,582 with DKD). Analysis of specific DKD phenotypes identified a novel signal near GABRR1 (rs9942471, P = 4.5 x 10(-8)) associated with microalbuminuria in European T2D case subjects. However, no replication of this signal was observed in Asian subjects with T2D or in the equivalent T1D analysis. There was only limited support, in this substantially enlarged analysis, for association at previously reported DKD signals, except for those at UMOD and PRKAG2, both associated with estimated glomerular filtration rate. We conclude that, despite challenges in addressing phenotypic heterogeneity, access to increased sample sizes will continue to provide more robust inference regarding risk variant discovery for DKD.Peer reviewe
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