702 research outputs found

    Global analysis of serine/threonine and tyrosine protein phosphatase catalytic subunit genes in Neurospora crassa reveals interplay between phosphatases and the p38 mitogen-activated protein kinase.

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    Protein phosphatases are integral components of the cellular signaling machinery in eukaryotes, regulating diverse aspects of growth and development. The genome of the filamentous fungus and model organism Neurospora crassa encodes catalytic subunits for 30 protein phosphatase genes. In this study, we have characterized 24 viable N. crassa phosphatase catalytic subunit knockout mutants for phenotypes during growth, asexual development, and sexual development. We found that 91% of the mutants had defects in at least one of these traits, whereas 29% possessed phenotypes in all three. Chemical sensitivity screens were conducted to reveal additional phenotypes for the mutants. This resulted in the identification of at least one chemical sensitivity phenotype for 17 phosphatase knockout mutants, including novel chemical sensitivities for two phosphatase mutants lacking a growth or developmental phenotype. Hence, chemical sensitivity or growth/developmental phenotype was observed for all 24 viable mutants. We investigated p38 mitogen-activated protein kinase (MAPK) phosphorylation profiles in the phosphatase mutants and identified nine potential candidates for regulators of the p38 MAPK. We demonstrated that the PP2C class phosphatase pph-8 (NCU04600) is an important regulator of female sexual development in N. crassa. In addition, we showed that the Δcsp-6 (ΔNCU08380) mutant exhibits a phenotype similar to the previously identified conidial separation mutants, Δcsp-1 and Δcsp-2, that lack transcription factors important for regulation of conidiation and the circadian clock

    Using non-smooth multi-domain dynamics to improve the safety on haul roads in surface mining

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    The paper presents a preliminary numerical study aimed to improve the safety on haul roads in surface mining. The interaction and collision between granular berms and ultra-class haul trucks are investigated by using non-smooth multi-domain dynamics. The haul truck is modelled as a rigid multibody system and the granular berm as a distribution of rigid particles using the discrete element method. A non-smooth dynamics approach is applied to enable stable and time-efficient simulation of the full system with strong coupling. The numerical model is first calibrated using full-scale data from experimental tests and then applied to investigate the collision between the haul truck and granular berms of different geometry under various approach conditions

    The guanine nucleotide exchange factor RIC8 regulates conidial germination through Gα proteins in Neurospora crassa.

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    Heterotrimeric G protein signaling is essential for normal hyphal growth in the filamentous fungus Neurospora crassa. We have previously demonstrated that the non-receptor guanine nucleotide exchange factor RIC8 acts upstream of the Gα proteins GNA-1 and GNA-3 to regulate hyphal extension. Here we demonstrate that regulation of hyphal extension results at least in part, from an important role in control of asexual spore (conidia) germination. Loss of GNA-3 leads to a drastic reduction in conidial germination, which is exacerbated in the absence of GNA-1. Mutation of RIC8 leads to a reduction in germination similar to that in the Δgna-1, Δgna-3 double mutant, suggesting that RIC8 regulates conidial germination through both GNA-1 and GNA-3. Support for a more significant role for GNA-3 is indicated by the observation that expression of a GTPase-deficient, constitutively active gna-3 allele in the Δric8 mutant leads to a significant increase in conidial germination. Localization of the three Gα proteins during conidial germination was probed through analysis of cells expressing fluorescently tagged proteins. Functional TagRFP fusions of each of the three Gα subunits were constructed through insertion of TagRFP in a conserved loop region of the Gα subunits. The results demonstrated that GNA-1 localizes to the plasma membrane and vacuoles, and also to septa throughout conidial germination. GNA-2 and GNA-3 localize to both the plasma membrane and vacuoles during early germination, but are then found in intracellular vacuoles later during hyphal outgrowth

    Collagen organization within the cartilage of TRPV4(-/-) mice studied with two-photon microscopy and polarized second harmonic generation

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    The polymodal channel TRPV4 has been shown to regulate development and maintenance of cartilage. Here we investigate whether TRPV4 activity regulates the early deposition and structure of collagen matrix in the femoral head cartilage by comparing the 3D morphology and the sub-micrometer organization of the collagen matrix between wild type and TRPV4(-/-) mice pups four to five days old. Two-photon microscopy can be used to conduct label-free imaging of cartilage, as collagen generates a second harmonic signal (second harmonic generation [SHG]) under pulsed infrared excitation. In one set of measurements, we use circularly polarized laser light to reconstruct the 3D morphology of the femoral head cartilage and to measure the tissue thickness. Second, by rotating the direction of the linearly polarized light and using polarized SHG detection, we investigate the sub-micrometer orientation of collagen fibers in the cartilage. At this developmental stage, we cannot detect statistically significant differences between the two mice strains, although a tendency toward a more random orientation of collagen fibers and a higher thickness of the whole cartilage seems to characterize the TRPV4(-/-) mice. We discuss possible reasons for these observations

    Resonant interaction between gravitational waves, electromagnetic waves and plasma flows

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    In magnetized plasmas gravitational and electromagnetic waves may interact coherently and exchange energy between themselves and with plasma flows. We derive the wave interaction equations for these processes in the case of waves propagating perpendicular or parallel to the plasma background magnetic field. In the latter case, the electromagnetic waves are taken to be circularly polarized waves of arbitrary amplitude. We allow for a background drift flow of the plasma components which increases the number of possible evolution scenarios. The interaction equations are solved analytically and the characteristic time scales for conversion between gravitational and electromagnetic waves are found. In particular, it is shown that in the presence of a drift flow there are explosive instabilities resulting in the generation of gravitational and electromagnetic waves. Conversely, we show that energetic waves can interact to accelerate particles and thereby \emph{produce} a drift flow. The relevance of these results for astrophysical and cosmological plasmas is discussed.Comment: 12 pages, 1 figure, typos corrected and numerical example adde

    Global Analysis of Serine-Threonine Protein Kinase Genes in Neurospora Crassa

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    Serine/threonine (S/T) protein kinases are crucial components of diverse signaling pathways in eukaryotes, including the model filamentous fungus Neurospora crassa. In order to assess the importance of S/T kinases to Neurospora biology, we embarked on a global analysis of 86 S/T kinase genes in Neurospora. We were able to isolate viable mutants for 77 of the 86 kinase genes. Of these, 57% exhibited at least one growth or developmental phenotype, with a relatively large fraction (40%) possessing a defect in more than one trait. S/T kinase knockouts were subjected to chemical screening using a panel of eight chemical treatments, with 25 mutants exhibiting sensitivity or resistance to at least one chemical. This brought the total percentage of S/T mutants with phenotypes in our study to 71%. Mutants lacking apg-1, an S/T kinase required for autophagy in other organisms, possessed the greatest number of phenotypes, with defects in asexual and sexual growth and development and in altered sensitivity to five chemical treatments. We showed that NCU02245/stk-19 is required for chemotropic interactions between female and male cells during mating. Finally, we demonstrated allelism between the S/T kinase gene NCU00406 and velvet (vel), encoding a p21-activated protein kinase (PAK) gene important for asexual and sexual growth and development in Neurospora

    Genome Sequence of a Novel Archaeal Fusellovirus Assembled from the Metagenome of a Mexican Hot Spring

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    The consensus genome sequence of a new member of the family Fuselloviridae designated as SMF1 (Sulfolobales Mexican fusellovirus 1) is presented. The complete circular genome was recovered from a metagenomic study of a Mexican hot spring. SMF1 exhibits an exceptional coding strand bias and a reduced set of fuselloviral core genes

    Analysis of friction coefficient for a base steel 5 % Cr, applying variable loads of 196 N, 294 N and 392 N, and speeds of 0,18 m/sec, 0,36 m/sec and 0,54 m/sec

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    The present study consists in analyzing the friction coefficient as a variable of the normal load and slip speed for 5% Cr steel, by applying the Block-on-Disk method according to ASTM D2714. The friction coefficient increases linearly 23,25 % from 0,214 to 0,266 when the load is increased from 196 N to 392 N; the same phenomenon is observed when the friction coefficient increases 47,82 % from 0,23 to 0,34 when the slip speed increases from 0,18 m/sec to 0,54 m/sec. The friction coefficient increased by 23,25 % for an increase in the load from 196 N to 392 N, which corresponds to 100 %, while an increase of the friction coefficient of 47,82 % occurred by increasing the speed from 0,18 m/sec to 0,54 m/sec which corresponds to 200 %

    Identifying contributors to disparities in patient access of online medical records: Examining the role of clinician encouragement

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    OBJECTIVE: The aim of this study was to understand the influence of clinician encouragement and sociodemographic factors on whether patients access online electronic medical records (EMR). MATERIALS AND METHODS: We analyzed 3279 responses from the Health Information National Trends Survey 5 cycle 4 survey, a cross-sectional, nationally representative survey administered by the National Cancer Institute. Frequencies and weighted proportions were calculated to compare clinical encouragement and access to their online EMR. Using multivariate logistic regression, we identified factors associated with online EMR use and clinician encouragement. RESULTS: In 2020, an estimated 42% of US adults accessed their online EMR and 51% were encouraged by clinicians to access their online EMR. In multivariate regression, respondents who accessed EMR were more likely to have received clinician encouragement (odds ratio [OR], 10.3; 95% confidence interval [CI], 7.7-14.0), college education or higher (OR, 1.9; 95% CI, 1.4-2.7), history of cancer (OR, 1.5; 95% CI, 1.0-2.3), and history of chronic disease (OR, 2.3; 95% CI, 1.7-3.2). Male and Hispanic respondents were less likely to have accessed EMR than female and non-Hispanic White respondents (OR, 0.6; 95% CI, 0.5-0.8, and OR, 0.5; 95% CI, 0.3-0.8, respectively). Respondents receiving encouragement from clinicians were more likely to be female (OR, 1.7; 95% CI, 1.3-2.3), have college education (OR, 1.5; 95% CI, 1.1-2.0), history of cancer (OR, 1.8; 95% CI, 1.3-2.5), and greater income levels (OR, 1.8-3.6). DISCUSSION: Clinician encouragement of patient EMR use is strongly associated with patients accessing EMR, and there are disparities in who receives clinician encouragement related to education, income, sex, and ethnicity. CONCLUSIONS: Clinicians have an important role to ensure that all patients benefit from online EMR use
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