641 research outputs found
Relationship of an Employee Fitness Program to Costcontainment Variables of Absenteeism and Medical Costs
This study was concerned with examining cost-containment variables of absenteeism and medical costs in relation to an employee fitness program, It was hypothesized that there would not be a significant difference between a group of exercisers and a control group regarding the above variables at the .05 level of confidence. Employees consisted of men between the ages of 50-59 at a large industry in the Midwest. Absenteeism in the exercise group was found to be significant at the .05 level of confidence utilizing the left-tailed Z test. Medical costs were not found to be significant between the two groups at the .05 level of confidence using the left-tailed Z test. However, there was a difference in medical costs in favor of the exercisers.Educationa
ERCC1/XPF protects short telomeres from homologous recombination in Arabidopsis thaliana.
International audienceMany repair and recombination proteins play essential roles in telomere function and chromosome stability, notwithstanding the role of telomeres in "hiding" chromosome ends from DNA repair and recombination. Among these are XPF and ERCC1, which form a structure-specific endonuclease known for its essential role in nucleotide excision repair and is the subject of considerable interest in studies of recombination. In contrast to observations in mammalian cells, we observe no enhancement of chromosomal instability in Arabidopsis plants mutated for either XPF (AtRAD1) or ERCC1 (AtERCC1) orthologs, which develop normally and show wild-type telomere length. However, in the absence of telomerase, mutation of either of these two genes induces a significantly earlier onset of chromosomal instability. This early appearance of telomere instability is not due to a general acceleration of telomeric repeat loss, but is associated with the presence of dicentric chromosome bridges and cytologically visible extrachromosomal DNA fragments in mitotic anaphase. Such extrachromosomal fragments are not observed in later-generation single-telomerase mutant plants presenting similar frequencies of anaphase bridges. Extensive FISH analyses show that these DNAs are broken chromosomes and correspond to two specific chromosome arms. Analysis of the Arabidopsis genome sequence identified two extensive blocks of degenerate telomeric repeats, which lie at the bases of these two arms. Our data thus indicate a protective role of ERCC1/XPF against 3' G-strand overhang invasion of interstitial telomeric repeats. The fact that the Atercc1 (and Atrad1) mutants dramatically potentiate levels of chromosome instability in Attert mutants, and the absence of such events in the presence of telomerase, have important implications for models of the roles of recombination at telomeres and is a striking illustration of the impact of genome structure on the outcomes of equivalent recombination processes in different organisms
Special considerations for studies of extracellular vesicles from parasitic helminths: A community-led roadmap to increase rigour and reproducibility
Over the last decade, research interest in defining how extracellular vesicles (EVs) shape cross-species communication has grown rapidly. Parasitic helminths, worm species found in the phyla Nematoda and Platyhelminthes, are well-recognised manipulators of host immune function and physiology. Emerging evidence supports a role for helminth-derived EVs in these processes and highlights EVs as an important participant in cross-phylum communication. While the mammalian EV field is guided by a community-agreed framework for studying EVs derived from model organisms or cell systems [e.g., Minimal Information for Studies of Extracellular Vesicles (MISEV)], the helminth community requires a supplementary set of principles due to the additional challenges that accompany working with such divergent organisms. These challenges include, but are not limited to, generating sufficient quantities of EVs for descriptive or functional studies, defining pan-helminth EV markers, genetically modifying these organisms, and identifying rigorous methodologies for in vitro and in vivo studies. Here, we outline best practices for those investigating the biology of helminth-derived EVs to complement the MISEV guidelines. We summarise community-agreed standards for studying EVs derived from this broad set of non-model organisms, raise awareness of issues associated with helminth EVs and provide future perspectives for how progress in the field will be achieved
Hyperautofluorescent Dots are Characteristic in Ceramide Kinase Like-associated Retinal Degeneration.
There is a lack of studies which seek to discern disease expression in patients with mutations that alter retinal ceramide metabolism, specifically in the ceramide kinase like (CERKL) gene. This cross-sectional case series reports a novel phenotypic manifestation of CERKL-associated retinopathy. Four unrelated patients with homozygous CERKL mutations underwent a complete ocular exam, spectral-domain optical coherence tomography, short-wavelength fundus autofluorescence (SW-AF), quantitative autofluorescence (qAF), and full-field electroretinogram (ffERG). Decreased visual acuity and early-onset maculopathy were present in all patients. All four patients had extensive hyperautofluorescent foci surrounding an area of central atrophy on SW-AF imaging, which has not been previously characterized. An abnormal spatial distribution of qAF signal was seen in one patient, and abnormally elevated qA
Bacillus methanolicus sp. nov., a New Species of Thermotolerant, Methanol-Utilizing, Endospore-Forming Bacteria
The generic position of 14 strains of gram-positive bacteria able to use methanol as a growth substrate was determined. All are obligately aerobic, thermotolerant organisms that are able to grow at temperatures of 35 to 60°C. Nine of the strains produce oval spores at a subterminal-to-central position in slightly swollen rod-shaped cells. DNA-DNA hybridization studies, 5S rRNA sequence analysis, and physiological characteristics revealed that all 14 strains cluster as a well-defined group and form a distinct new genospecies. Analysis of the 16S and 5S rRNA sequences indicated that this new species is distinct from Bacillus brevis but closely related to B. firmus and B. azotoformans. The name proposed for this new species is B. methanolicus. The type strain, PB1, has been deposited in the National Collection of Industrial and Marine Bacteria as NCIMB 13113
Novel Genes Involved in Resistance to Both Ultraviolet Radiation and Perchlorate From the Metagenomes of Hypersaline Environments
Microorganisms that thrive in hypersaline environments on the surface of our planet are exposed to the harmful effects of ultraviolet radiation. Therefore, for their protection, they have sunscreen pigments and highly efficient DNA repair and protection systems. The present study aimed to identify new genes involved in UV radiation resistance from these microorganisms, many of which cannot be cultured in the laboratory. Thus, a functional metagenomic approach was used and for this, small-insert libraries were constructed with DNA isolated from microorganisms of high-altitude Andean hypersaline lakes in Argentina (Diamante and Ojo Seco lakes, 4,589 and 3,200 m, respectively) and from the Es Trenc solar saltern in Spain. The libraries were hosted in a UV radiation-sensitive strain of Escherichia coli (recA mutant) and they were exposed to UVB. The resistant colonies were analyzed and as a result, four clones were identified with environmental DNA fragments containing five genes that conferred resistance to UV radiation in E. coli. One gene encoded a RecA-like protein, complementing the mutation in recA that makes the E. coli host strain more sensitive to UV radiation. Two other genes from the same DNA fragment encoded a TATA-box binding protein and an unknown protein, both responsible for UV resistance. Interestingly, two other genes from different and remote environments, the Ojo Seco Andean lake and the Es Trenc saltern, encoded two hypothetical proteins that can be considered homologous based on their significant amino acid similarity (49%). All of these genes also conferred resistance to 4-nitroquinoline 1-oxide (4-NQO), a compound that mimics the effect of UV radiation on DNA, and also to perchlorate, a powerful oxidant that can induce DNA damage. Furthermore, the hypothetical protein from the Es Trenc salterns was localized as discrete foci possibly associated with damaged sites in the DNA in cells treated with 4-NQO, so it could be involved in the repair of damaged DNA. In summary, novel genes involved in resistance to UV radiation, 4-NQO and perchlorate have been identified in this work and two of them encoding hypothetical proteins that could be involved in DNA damage repair activities not previously described.Fil: Lamprecht GrandÃo, MarÃa. Consejo Superior de Investigaciones Cientificas. Centro de Astrobiologia.; EspañaFil: Cortesão, Marta. Consejo Superior de Investigaciones Cientificas. Centro de Astrobiologia.; EspañaFil: Mirete, Salvador. Consejo Superior de Investigaciones Cientificas. Centro de Astrobiologia.; EspañaFil: Benguigui de la Cámara, Macarena. Consejo Superior de Investigaciones Cientificas. Centro de Astrobiologia.; EspañaFil: de Figueras, Carolina G.. Consejo Superior de Investigaciones Cientificas. Centro de Astrobiologia.; EspañaFil: Pérez Pantoja, Danilo. Universidad Tecnológica Metropolitana; EspañaFil: White, Joseph John. Consejo Superior de Investigaciones Cientificas. Centro de Astrobiologia.; EspañaFil: Farias, Maria Eugenia. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Rosselló Móra, Ramon. Instituto Mediterráneo Estudios Avanzados; EspañaFil: González Pastor, José Eduardo. Consejo Superior de Investigaciones Cientificas. Centro de Astrobiologia.; Españ
Grey-matter texture abnormalities and reduced hippocampal volume are distinguishing features of schizophrenia
Neurodevelopmental processes are widely believed to underlie schizophrenia. Analysis of
brain texture from conventional magnetic resonance imaging (MRI) can detect disturbance in
brain cytoarchitecture. We tested the hypothesis that patients with schizophrenia manifest
quantitative differences in brain texture that, alongside discrete volumetric changes, may
serve as an endophenotypic biomarker. Texture analysis (TA) of grey matter distribution and
voxel-based morphometry (VBM) of regional brain volumes were applied to MRI scans of 27
patients with schizophrenia and 24 controls. Texture parameters (uniformity and entropy)
were also used as covariates in VBM analyses to test for correspondence with regional brain
volume. Linear discriminant analysis tested if texture and volumetric data predicted
diagnostic group membership (schizophrenia or control). We found that uniformity and
entropy of grey matter differed significantly between individuals with schizophrenia and
controls at the fine spatial scale (filter width below 2 mm). Within the schizophrenia group,
these texture parameters correlated with volumes of the left hippocampus, right amygdala
and cerebellum. The best predictor of diagnostic group membership was the combination of
fine texture heterogeneity and left hippocampal size. This study highlights the presence of
distributed grey-matter abnormalities in schizophrenia, and their relation to focal structural
abnormality of the hippocampus. The conjunction of these features has potential as a
neuroimaging endophenotype of schizophrenia
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