531 research outputs found
Characterisation of Agaricus bisporus response genes to Verticillium fungicola infection
Resumen de la conferencia presentada al VI Meeting on Genetics and Cellular Biology of Basidiomycetes (GCBB-VI), organizado por y celebrado en la Universidad PĂșblica de Navarra el 3-6 de junio de 2005.The mycoparasite Verticillium fungicola is a persistent threat to the cultivation
of the mushroom Agaricus bisporus. Mushroom âdry bubbleâ is characterised
by an undifferentiated mass of cells and can result in major crop losses. During
the establishment of âdry bubbleâ substantial changes occur in the biochemistry
and physiology of both partners. To enable new insights to be
made into the molecular events underlying the disease, work is in progress to
identify genes expressed during pathogen infection. Subtractive Suppressive
Hybridisation (SSH) has enabled recovery of 65 expressed sequenced tags
(ESTs) differentially expressed during infection. After database searches 27
of the genes were identified as most likely from V. fungicola, 25 from A. bisporus
and 13 unknown. Bioinformatic analysis suggested that the response
genes identified were involved in a range of biological functions that included
stress, signalling, protein synthesis and cell wall structure and function.
Specific full-length genes will be recovered using cDNA library constructed
from lesions of A. bisporus infected with V. fungicola, enabling silencing
approaches to be used to further investigate the role of the identified
genes in disease. An alternative higher-throughput method of gene function
analysis, RNA interference (RNAi) using A. bisporus model genes (URA3,
CBX), is also being developed. Silencing constructs expressing RNAi hairpin
were transformed into A. bisporus using Agrobacterium tumefaciens and hygromycin
resistance. Screening of the transformants by PCR confirmed integration
of the silencing construct in 24 transformants. RT-PCR is being
used to confirm transcription of the RNAi hairpin. Quantitative PCR will be
used to analyse levels of target gene transcripts post RNAi transformation.
The role of A. bisporus genes identified, in the infection process, will be determined
through infection trails with A. bisporus silenced lines
Molecular toolkit development for gene expression and gene silencing technologies in the homobasidiomycete Fungi Agaricus bisporus and Coprinus cinereus
Resumen de la conferencia presentada al VI Meeting on Genetics and Cellular Biology of Basidiomycetes (GCBB-VI), organizado por y celebrado en la Universidad PĂșblica de Navarra el 3-6 de junio de 2005.We have developed a âMolecular Toolkitâ comprising interchangeable promoters
and marker genes to facilitate transformation of homobasidiomycete
mushrooms and subsequent analysis of gene expression. We will describe the
testing of a wide range of promoters in both Agaricus bisporus and Coprinus
cinereus when linked to a range of selectable and visual marker genes, along
with the parameters required to successfully achieve foreign gene expression
within these organisms. It has been previously demonstrated that a prerequisite
for GFP expression in A. bisporus and C. cinereus is an intron. We describe
the construction of an expression vector containing a multiple cloning
site linked to an intron thus allowing different genes to be easily expressed in
A. bisporus and C. cinereus. We report on the development of gene silencing
technologies within A. bisporus and C. cinereus. In particular the serine protease
has been targeted for gene silencing in A. bisporus. Serine protease has
been implicated in post-harvest and age-related senescence of sporophores.
On harvesting, mushrooms degenerate rapidly to give browned caps and loss
of texture in the fruit body, and such problems can dramatically reduce sale
ability of the mushrooms. Suppression of genes involved in these pathways
could increase mushroom shelf-life and profitability for mushroom growers,
or help to further elucidate the complex biochemical pathways involved in
post-harvest degradation. Progress will also be reported on gene silencing in
C. cinereus
What do young athletes implicitly understand about psychological skills?
One reason sport psychologists teach psychological skills is to enhance performance in sport; but the value of psychological skills for young athletes is questionable because of the qualitative and quantitative differences between children and adults in their understanding of abstract concepts such as mental skills. To teach these skills effectively to young athletes, sport psychologists need to appreciate what young athletes implicitly understand about such skills because maturational (e.g., cognitive, social) and environmental (e.g., coaches) factors can influence the progressive development of children and youth. In the present qualitative study, we explored young athletesâ (aged 10â15 years) understanding of four basic psychological skills: goal setting, mental imagery, self-talk, and relaxation. Young athletes (n = 118: 75 males and 43 females) completed an open-ended questionnaire to report their understanding of these four basic psychological skills. Compared with the older youth athletes, the younger youth athletes were less able to explain the meaning of each psychological skill. Goal setting and mental imagery were better understood than self-talk and relaxation. Based on these findings, sport psychologists should consider adapting interventions and psychoeducational programs to match young athletesâ age and developmental level
Characterisation of the temperature-dependent dark rate of Hamamatsu R7081-100 10" photomultiplier tubes
Dark noise is a dominant background in photomultiplier tubes (PMTs), which are commonly used in liquid-filled particle detectors for single-photon detection to see the results of particle interactions. A major contribution to dark noise is thermionic emission from the photocathode. The dark noise of Hamamatsu R7081-100 PMTs is characterised in a temperature and purity controlled water tank, with the thermionic emission contribution isolated. The results suggest that the intrinsic dark rate of PMTs does not depend on the medium, but does follow Richardson's law of thermionic emission. There are external contributions to the overall observed PMT count rate identified, but the intrinsic PMT dark rate in water matches that measured in air
Can forest management based on natural disturbances maintain ecological resilience?
Given the increasingly global stresses on forests, many ecologists argue that managers must maintain ecological resilience: the capacity of ecosystems to absorb disturbances without undergoing fundamental change. In this review we ask: Can the emerging paradigm of natural-disturbance-based management (NDBM) maintain ecological resilience in managed forests? Applying resilience theory requires careful articulation of the ecosystem state under consideration, the disturbances and stresses that affect the persistence of possible alternative states, and the spatial and temporal scales of management relevance. Implementing NDBM while maintaining resilience means recognizing that (i) biodiversity is important for long-term ecosystem persistence, (ii) natural disturbances play a critical role as a generator of structural and compositional heterogeneity at multiple scales, and (iii) traditional management tends to produce forests more homogeneous than those disturbed naturally and increases the likelihood of unexpected catastrophic change by constraining variation of key environmental processes. NDBM may maintain resilience if silvicultural strategies retain the structures and processes that perpetuate desired states while reducing those that enhance resilience of undesirable states. Such strategies require an understanding of harvesting impacts on slow ecosystem processes, such as seed-bank or nutrient dynamics, which in the long term can lead to ecological surprises by altering the forest's capacity to reorganize after disturbance
Pulsar timing arrays and the challenge of massive black hole binary astrophysics
Pulsar timing arrays (PTAs) are designed to detect gravitational waves (GWs)
at nHz frequencies. The expected dominant signal is given by the superposition
of all waves emitted by the cosmological population of supermassive black hole
(SMBH) binaries. Such superposition creates an incoherent stochastic
background, on top of which particularly bright or nearby sources might be
individually resolved. In this contribution I describe the properties of the
expected GW signal, highlighting its dependence on the overall binary
population, the relation between SMBHs and their hosts, and their coupling with
the stellar and gaseous environment. I describe the status of current PTA
efforts, and prospect of future detection and SMBH binary astrophysics.Comment: 18 pages, 4 figures. To appear in the Proceedings of the 2014 Sant
Cugat Forum on Astrophysics. Astrophysics and Space Science Proceedings, ed.
C.Sopuerta (Berlin: Springer-Verlag
Cardiometabolic Risk Assessments by Body Mass Index z -Score or Waist-to-Height Ratio in a Multiethnic Sample of Sixth-Graders
Convention defines pediatric adiposity by the body mass index z-score (BMIz) referenced to normative growth charts. Waist-to-height ratio (WHtR) does not depend on sex-and-age references. In the HEALTHY Study enrollment sample, we compared BMIz with WHtR for ability to identify adverse cardiometabolic risk. Among 5,482 sixth-grade students from 42 middle schools, we estimated explanatory variations (R2) and standardized beta coefficients of BMIz or WHtR for cardiometabolic risk factors: insulin resistance (HOMA-IR), lipids, blood pressures, and glucose. For each risk outcome variable, we prepared adjusted regression models for four subpopulations stratified by sex and high versus lower fatness. For HOMA-IR, R2 attributed to BMIz or WHtR was 19%-28% among high-fatness and 8%-13% among lower-fatness students. R2 for lipid variables was 4%-9% among high-fatness and 2%-7% among lower-fatness students. In the lower-fatness subpopulations, the standardized coefficients for total cholesterol/HDL cholesterol and triglycerides tended to be weaker for BMIz (0.13-0.20) than for WHtR (0.17-0.28). Among high-fatness students, BMIz and WHtR correlated with blood pressures for Hispanics and whites, but not black boys (systolic) or girls (systolic and diastolic). In 11-12 year olds, assessments by WHtR can provide cardiometabolic risk estimates similar to conventional BMIz without requiring reference to a normative growth chart
Efficacy of a Commercial Weight Management Program Compared with a Do-It-Yourself Approach: A Randomized Clinical Trial
Importance: Given the prevalence of obesity, accessible and effective treatment options are needed to manage obesity and its comorbid conditions. Commercial weight management programs are a potential solution to the lack of available treatment, providing greater access at lower cost than clinic-based approaches, but few commercial programs have been rigorously evaluated. Objective: To compare the differences in weight change between individuals randomly assigned to a commercial weight management program and those randomly assigned to a do-it-yourself (DIY) approach. Design, Setting, and Participants: This 1-year, randomized clinical trial conducted in the United States, Canada, and United Kingdom between June 19, 2018, and November 30, 2019, enrolled 373 adults aged 18 to 75 years with a body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) of 25 to 45. Assessors were blinded to treatment conditions. Interventions: A widely available commercial weight management program that included reduced requirements for dietary self-monitoring and recommendations for a variety of DIY approaches to weight loss. Main Outcomes and Measures: The primary outcomes were the difference in weight change between the 2 groups at 3 and 12 months. The a priori hypothesis was that the commercial program would result in greater weight loss than the DIY approach at 3 and 12 months. Analyses were performed on an intention-To-Treat basis. Results: The study include 373 participants (272 women [72.9%]; mean [SD] BMI, 33.8 [5.2]; 77 [20.6%] aged 18-34 years, 74 [19.8%] aged 35-43 years, 82 [22.0%] aged 44-52 years, and 140 [37.5%] aged 53-75 years). At 12 months, retention rates were 88.8% (166 of 187) for the commercial weight management program group and 95.7% (178 of 186) for the DIY group. At 3 months, participants in the commercial program had a mean (SD) weight loss of-3.8 (4.1) kg vs-1.8 (3.7) kg among those in the DIY group. At 12 months, participants in the commercial program had a mean (SD) weight loss of-4.4 (7.3) kg vs-1.7 (7.3) kg among those in the DIY group. The mean difference between groups was-2.0 kg (97.5% CI,-2.9 to-1.1 kg) at 3 months (P <.001) and-2.6 kg (97.5% CI,-4.3 to-0.8 kg) at 12 months (P <.001). A greater percentage of participants in the commercial program group than participants in the DIY group achieved loss of 5% of body weight at both 3 months (40.7% [72 of 177] vs 18.6% [34 of 183]) and 12 months (42.8% [71 of 166] vs 24.7% [44 of 178]). Conclusions and Relevance: Adults randomly assigned to a commercial weight management program with reduced requirements for dietary self-monitoring lost more weight and were more likely to achieve weight loss of 5% at 3 and 12 months than adults following a DIY approach. This study contributes data on the efficacy of commercial weight management programs and DIY weight management approaches. Trial Registration: ClinicalTrials.gov Identifier: NCT03571893
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