1,626 research outputs found
The guanine nucleotide exchange factor RIC8 regulates conidial germination through Gα proteins in Neurospora crassa.
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
Associations Between Imprinted Gene Expression in the Placenta, Human Fetal Growth and Preeclampsia
Genomic imprinting is essential for normal placental and fetal growth. One theory to explain the evolution of imprinting is the kinship theory (KT), which predicts that genes that are paternally expressed will promote fetal growth, whereas maternally expressed genes will suppress growth. We investigated the expression of imprinted genes using microarray measurements of expression in term placentae. Correlations between birthweight and the expression levels of imprinted genes were more significant than for non-imprinted genes, but did not tend to be positive for paternally expressed genes and negative for maternally expressed genes. Imprinted genes were more dysregulated in preeclampsia (a disorder associated with placental insufficiency) than randomly selected genes, and we observed an excess of patterns of dysregulation in preeclampsia that would be expected to reduce nutrient allocation to the fetus, given the predictions of the KT. However, we found no evidence of coordinated regulation among these imprinted genes. A few imprinted genes have previously been shown to be associated with fetal growth and preeclampsia, and our results indicate that this is true for a broader set of imprinted genes
Erratum. Sodium-Glucose Cotransporter 2 Inhibition and Diabetic Kidney Disease. Diabetes 2019;68:248-257.
The Affordable Care Act: U.S. Vaccine Policy and Practice
When fully implemented, the Patient Protection and Affordable Care Act, amended by the Health and Education Reconciliation Act will extend health insurance coverage to 94 percent of Americans while establishing a comprehensive set of strategies to improve care and contain costs. The central provisions of the Act – guaranteed affordable and accessible coverage – take effect January 1, 2014. Important insurance reforms aimed at improving coverage become effective before that date, as do a series of investments aimed at improving the accessibility and quality of health care.
This report has several aims: 1) to examine how the laws address vaccine policy and practice; 2) to assess how access to vaccines and immunization services will be affected; and 3) to assess the extent to which health reform addresses recommendations of the National Vaccine Advisory Committee\u27s (NVAC) Vaccine Finance Working Group (VFWG) 2008
Confocal imaging to reveal the microstructure of soybean processing materials
�� 2014 The Authors. Published by Elsevier. This is an open access article available under a Creative Commons licence.
The published version can be accessed at the following link on the publisher���s website: https://doi.org/10.1016/j.jfoodeng.2014.09.022Sustainable production of food products for human consumption is required to reduce negative impacts on the environment and to consumer���s health. Soybeans are an excellent source of nutritive plant proteins; aqueous extraction yields part of the available oil and protein from the legume. Many studies have been conducted which detail the various processing parameters and their effects on the extraction yields, yet there is little data on the localisation of nutritive components such as oil and protein in the fibrous unextracted by-product. Here we show a novel confocal laser scanning microscopy investigation of soybean processing materials and the physical effects of thermal treatment on the materials microstructure upon aqueous extraction. Various features, more specifically oil, protein (including protein aggregation) and cell wall structures, are visualised in the fibrous by-product, soy slurry and soy extract, with their presence both in the continuous phase and within intact cotyledon cells. Thermal treatment reduced the protein extraction yield; this is shown to be a result of aggregated protein bodies in the continuous phase and within intact cotyledons cells. Knowledge of the processing material microstructures can be applied to improve extraction yields and reduce waste production
ERK/MAPK Signaling Drives Overexpression of the Rac-GEF, PREX1, in BRAF- and NRAS-Mutant Melanoma
Recently we identified that PREX1 overexpression is critical for metastatic but not tumorigenic growth in a mouse model of NRAS-driven melanoma. In addition, a PREX1 gene signature correlated with and was dependent on ERK mitogen-activated protein kinase (MAPK) activation in human melanoma cell lines. In the current study, the underlying mechanism of PREX1 overexpression in human melanoma was assessed. PREX1 protein levels were increased in melanoma tumor tissues and cell lines compared with benign nevi and normal melanocytes, respectively. Suppression of PREX1 by siRNA impaired invasion but not proliferation in vitro. PREX1-dependent invasion was attributable to PREX1-mediated activation of the small GTPase RAC1 but not the related small GTPase CDC42. Pharmacologic inhibition of ERK signaling reduced PREX1 gene transcription and additionally regulated PREX1 protein stability. This ERK-dependent upregulation of PREX1 in melanoma, due to both increased gene transcription and protein stability, contrasts with the mechanisms identified in breast and prostate cancers, where PREX1 overexpression was driven by gene amplification and HDAC-mediated gene transcription, respectively. Thus, although PREX1 expression is aberrantly upregulated and regulates RAC1 activity and invasion in these three different tumor types, the mechanisms of its upregulation are distinct and context-dependent
Maleidride biosynthesis – construction of dimeric anhydrides – more than just heads or tails
Covering: up to early 2022 Maleidrides are a family of polyketide-based dimeric natural products isolated from fungi. Many maleidrides possess significant bioactivities, making them attractive pharmaceutical or agrochemical lead compounds. Their unusual biosynthetic pathways have fascinated scientists for decades, with recent advances in our bioinformatic and enzymatic understanding providing further insights into their construction. However, many intriguing questions remain, including exactly how the enzymatic dimerisation, which creates the diverse core structure of the maleidrides, is controlled. This review will explore the literature from the initial isolation of maleidride compounds in the 1930s, through the first full structural elucidation in the 1960s, to the most recent in vivo, in vitro, and in silico analyses
Heterologous Production of Fungal Maleidrides Reveals the Cryptic Cyclization Involved in their Biosynthesis
Fungal maleidrides are an important family of bioactive secondary metabolites that consist of 7, 8, or 9-membered carbocycles with one or two fused maleic anhydride moieties. The biosynthesis of byssochlamic acid (a nonadride) and agnestadride A (a heptadride) was investigated through gene disruption and heterologous expression experiments. The results reveal that the precursors for cyclization are formed by an iterative highly reducing fungal polyketide synthase supported by a hydrolase, together with two citrate-processing enzymes. The enigmatic ring formation is catalyzed by two proteins with homology to ketosteroid isomerases, and assisted by two proteins with homology to phosphatidylethanolamine-binding proteins. Ring cycle: The enzymes involved in the cyclization of the maleidride family of bioactive fungal natural products, including agnestadride A and byssochlamic acid, were identified. These previously unknown proteins show homology to ketosteroid isomerases (KI-like) and phosphatidylethanolamine-binding proteins (PEBP-like).BBSRCSyngent
Novel nonadride, heptadride and maleic acid metabolites from the byssochlamic acid producer <i>Byssochlamys fulva </i>IMI 40021 – an insight into the biosynthesis of maleidrides
The filamentous fungus Byssochlamys fulva strain IMI 40021 produces (+)-byssochlamic acid 1, its novel dihydroanalogue 2 and four related secondarymetabolites. Agnestadrides A, 17 and B, 18 constitute a novel class of seven-membered ring, maleic anhydride-containing (hence termed heptadride) natural products. The putative maleic anhydride precursor 5 for both nonadride and heptadride biosynthesis was isolated as a fermentation product for the first time and its structure confirmed by synthesis. Acid 5 undergoes facile decarboxylation to anhydride 6. The generic term maleidrides is proposed to encompass biosynthetically-related compounds containing maleic anhydride moieties fused to an alicyclic ring, varying in size and substituents
The Spatial Extent and Distribution of Star Formation in 3D-HST Mergers at z~1.5
We present an analysis of the spatial distribution of star formation in a
sample of 60 visually identified galaxy merger candidates at z>1. Our sample,
drawn from the 3D-HST survey, is flux-limited and was selected to have high
star formation rates based on fits of their broad-band, low spatial resolution
spectral energy distributions. It includes plausible pre-merger (close pairs)
and post-merger (single objects with tidal features) systems, with total
stellar masses and star formation rates derived from multi-wavelength
photometry. Here we use near-infrared slitless spectra from 3D-HST which
produce Halpha or [OIII] emission line maps as proxies for star-formation maps.
This provides a first comprehensive high-resolution, empirical picture of where
star formation occurred in galaxy mergers at the epoch of peak cosmic star
formation rate. We find that detectable star formation can occur in one or both
galaxy centres, or in tidal tails. The most common case (58%) is that star
formation is largely concentrated in a single, compact region, coincident with
the centre of (one of) the merger components. No correlations between star
formation morphology and redshift, total stellar mass, or star formation rate
are found. A restricted set of hydrodynamical merger simulations between
similarly massive and gas-rich objects implies that star formation should be
detectable in both merger components, when the gas fractions of the individual
components are the same. This suggests that z~1.5 mergers typically occur
between galaxies whose gas fractions, masses, and/or star formation rates are
distinctly different from one another.Comment: Accepted for publication in MNRAS, 16 pages, 10 figure
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