186 research outputs found
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Shared geriatric mental health care in a rural community
Introduction: A pilot project in shared mental health care was initiated to explore opportunities to increase the capacity of the rural primary care system as a resource for older people with mental health needs. This was done within a framework for the delivery of best practices in geriatric mental health outreach. Methods: Shared-care strategies combining education and clinical consultation between mentor psychiatrists and family physicians were implemented and then evaluated after one year to identify key factors in the success of approaches to shared mental health care for older people in a rural setting. Results: Results provided new insights into shared care between primary care and specialty geriatric mental health services, rural geriatric mental health service delivery, developmental phases in service learning approaches, and building knowledge networks to promote continuing best practices. Conclusion: The results from the project's process evaluation have been integrated into the development of a permanent shared geriatric mental health care service for the rural setting. Preparation for an outcome evaluation that will focus on the impact on patient care has also been initiated
Community structure and function of high-temperature chlorophototrophic microbial mats inhabiting diverse geothermal environments
Six phototrophic microbial mat communities from different geothermal springs (YNP) were studied using metagenome sequencing and geochemical analyses. The primary goals of this work were to determine differences in community composition of high-temperature phototrophic mats distributed across the Yellowstone geothermal ecosystem, and to identify metabolic attributes of predominant organisms present in these communities that may correlate with environmental attributes important in niche differentiation. Random shotgun metagenome sequences from six phototrophic communities (average~ 53 Mbp/site) were subjected to multiple taxonomic, phylogenetic and functional analyses. All methods, including G+C content distribution, MEGAN analyses and oligonucleotide frequency-based clustering, provided strong support for the dominant community members present in each site. Cyanobacteria were only observed in non-sulfidic sites; de novo assemblies were obtained for Synechococcus-like populations at Chocolate Pots (CP_7) and Fischerella-like populations at White Creek (WC_6). Chloroflexi-like sequences (esp. Roseiflexus and/or Chloroflexus spp.) were observed in all six samples and contained genes involved in bacteriochlorophyll biosynthesis and the 3-hydroxypropionate carbon fixation pathway. Other major sequence assemblies were obtained for a Chlorobiales population from CP_7 (proposed family Thermochlorobacteriaceae), and an anoxygenic, sulfur-oxidizing Thermochromatium-like (Gamma-proteobacteria) population from Bath Lake Vista Annex (BLVA_20). Additional sequence coverage is necessary to establish more complete assemblies of other novel bacteria in these sites (e.g., Bacteroidetes and Firmicutes); however, current assemblies suggested that several of these organisms play important roles in heterotrophic and fermentative metabolisms. Definitive linkages were established between several of the dominant phylotypes present in these habitats and important functional processes such a
Interplay of Mre11 Nuclease with Dna2 plus Sgs1 in Rad51-Dependent Recombinational Repair
The Mre11/Rad50/Xrs2 complex initiates IR repair by binding to the end of a double-strand break, resulting in 5′ to 3′ exonuclease degradation creating a single-stranded 3′ overhang competent for strand invasion into the unbroken chromosome. The nuclease(s) involved are not well understood. Mre11 encodes a nuclease, but it has 3′ to 5′, rather than 5′ to 3′ activity. Furthermore, mutations that inactivate only the nuclease activity of Mre11 but not its other repair functions, mre11-D56N and mre11-H125N, are resistant to IR. This suggests that another nuclease can catalyze 5′ to 3′ degradation. One candidate nuclease that has not been tested to date because it is encoded by an essential gene is the Dna2 helicase/nuclease. We recently reported the ability to suppress the lethality of a dna2Δ with a pif1Δ. The dna2Δ pif1Δ mutant is IR-resistant. We have determined that dna2Δ pif1Δ mre11-D56N and dna2Δ pif1Δ mre11-H125N strains are equally as sensitive to IR as mre11Δ strains, suggesting that in the absence of Dna2, Mre11 nuclease carries out repair. The dna2Δ pif1Δ mre11-D56N triple mutant is complemented by plasmids expressing Mre11, Dna2 or dna2K1080E, a mutant with defective helicase and functional nuclease, demonstrating that the nuclease of Dna2 compensates for the absence of Mre11 nuclease in IR repair, presumably in 5′ to 3′ degradation at DSB ends. We further show that sgs1Δ mre11-H125N, but not sgs1Δ, is very sensitive to IR, implicating the Sgs1 helicase in the Dna2-mediated pathway
Exoplanet Biosignatures: Understanding Oxygen as a Biosignature in the Context of Its Environment
Here we review how environmental context can be used to interpret whether O2
is a biosignature in extrasolar planetary observations. This paper builds on
the overview of current biosignature research discussed in Schwieterman et al.
(2017), and provides an in-depth, interdisciplinary example of biosignature
identification and observation that serves as a basis for the development of
the general framework for biosignature assessment described in Catling et al.,
(2017). O2 is a potentially strong biosignature that was originally thought to
be an unambiguous indicator for life at high-abundance. We describe the
coevolution of life with the early Earth's environment, and how the interplay
of sources and sinks in the planetary environment may have resulted in
suppression of O2 release into the atmosphere for several billion years, a
false negative for biologically generated O2. False positives may also be
possible, with recent research showing potential mechanisms in exoplanet
environments that may generate relatively high abundances of atmospheric O2
without a biosphere being present. These studies suggest that planetary
characteristics that may enhance false negatives should be considered when
selecting targets for biosignature searches. Similarly our ability to interpret
O2 observed in an exoplanetary atmosphere is also crucially dependent on
environmental context to rule out false positive mechanisms. We describe future
photometric, spectroscopic and time-dependent observations of O2 and the
planetary environment that could increase our confidence that any observed O2
is a biosignature, and help discriminate it from potential false positives. By
observing and understanding O2 in its planetary context we can increase our
confidence in the remote detection of life, and provide a model for
biosignature development for other proposed biosignatures.Comment: 55 pages. The paper is the second in a series of 5 review manuscripts
of the NExSS Exoplanet Biosignatures Workshop. Community commenting is
solicited at https://nexss.info/groups/ebww
Nonsense-mediated mRNA decay controls the changes in yeast ribosomal protein pre-mRNAs levels upon osmotic stress
The expression of ribosomal protein (RP) genes requires a substantial part of cellular transcription, processing and translation resources. Thus, the RP expression must be tightly regulated in response to conditions that compromise cell survival. In Saccharomyces cerevisiae cells, regulation of the RP gene expression at the transcriptional, mature mRNA stability and translational levels during the response to osmotic stress has been reported. Reprogramming global protein synthesis upon osmotic shock includes the movement of ribosomes from RP transcripts to stress-induced mRNAs. Using tiling arrays, we show that osmotic stress yields a drop in the levels of RP pre-mRNAs in S. cerevisiae cells. An analysis of the tiling array data, together with transcription rates data, shows a poor correlation, indicating that the drop in the RP pre-mRNA levels is not merely a result of the lowered RP transcription rates. A kinetic study using quantitative RT-PCR confirmed the decrease in the levels of several RP-unspliced transcripts during the first 15 minutes of osmotic stress, which seems independent of MAP kinase Hog1. Moreover, we found that the mutations in the components of the nonsense-mediated mRNA decay (NMD), Upf1, Upf2, Upf3 or in exonuclease Xrn1, eliminate the osmotic stress-induced drop in RP pre-mRNAs. Altogether, our results indicate that the degradation of yeast RP unspliced transcripts by NMD increases during osmotic stress, and suggest that this might be another mechanism to control RP synthesis during the stress response
Seasonality of MRSA Infections
Using MRSA isolates submitted to our hospital microbiology laboratory January 2001–March 2010 and the number of our emergency department (ED) visits, quarterly community-associated (CA) and hospital-associated (HA) MRSA infections were modeled using Poisson regressions. For pediatric patients, approximately 1.85x (95% CI 1.45x–2.36x, adj. p<0.0001) as many CA-MRSA infections per ED visit occurred in the second two quarters as occurred in the first two quarters. For adult patients, 1.14x (95% CI 1.01x–1.29x, adj.p = 0.03) as many infections per ED visit occurred in the second two quarters as in the first two quarters. Approximately 2.94x (95% CI 1.39x–6.21x, adj.p = 0.015) as many HA-MRSA infections per hospital admission occurred in the second two quarters as occurred in the first two quarters for pediatric patients. No seasonal variation was observed among adult HA-MRSA infections per hospital admission. We demonstrated seasonality of MRSA infections and provide a summary table of similar observations in other studies
H-Ras Expression in Immortalized Keratinocytes Produces an Invasive Epithelium in Cultured Skin Equivalents
Ras proteins affect both proliferation and expression of collagen-degrading enzymes, two important processes in cancer progression. Normal skin architecture is dependent both on the coordinated proliferation and stratification of keratinocytes, as well as the maintenance of a collagen-rich basement membrane. In the present studies we sought to determine whether expression of H-ras in skin keratinocytes would affect these parameters during the establishment and maintenance of an in vitro skin equivalent.Previously described cdk4 and hTERT immortalized foreskin keratinocytes were engineered to express ectopically introduced H-ras. Skin equivalents, composed of normal fibroblast-contracted collagen gels overlaid with keratinocytes (immortal or immortal expressing H-ras), were prepared and incubated for 3 weeks. Harvested tissues were processed and sectioned for histology and antibody staining. Antigens specific to differentiation (involucrin, keratin-14, p63), basement-membrane formation (collagen IV, laminin-5), and epithelial to mesenchymal transition (EMT; e-cadherin, vimentin) were studied. Results showed that H-ras keratinocytes produced an invasive, disorganized epithelium most apparent in the lower strata while immortalized keratinocytes fully stratified without invasive properties. The superficial strata retained morphologically normal characteristics. Vimentin and p63 co-localization increased with H-ras overexpression, similar to basal wound-healing keratinocytes. In contrast, the cdk4 and hTERT immortalized keratinocytes differentiated similarly to normal unimmortalized keratinocytes.The use of isogenic derivatives of stable immortalized keratinocytes with specified genetic alterations may be helpful in developing more robust in vitro models of cancer progression
Bernanke’s Paradox: Can He Reconcile His Position on the Federal Budget with His Recent Charge to Prevent Deflation?
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