1,351 research outputs found
The Global Ant Biodiversity Informatics (GABI) database: synthesizing data on the geographic distribution of ant species (Hymenoptera: Formicidae)
The global distribution patterns of most vertebrate groups and several plant groups have been described and analyzed over the past few years, a development facilitated by the compilation of important databases. Similar efforts are needed for large insect groups that constitute he majority of global biodiversity. As a result of this lack of information, invertebrate taxa are often left out of both large-scale analyses of biodiversity patterns and large-scale efforts in conservation planning and prioritization. Here, we introduce the first comprehensive global database of ant species distributions, the Global Ant Biodiversity Informatics (GABI) database, based on the compilation of 1.72 million records extracted from over 8811 publications and 25 existing databases. We first present the main goals of the database, the methodology used to build the database, is well as its limitations and challenges. Then, we discuss how different fields of ant biology may benefit from utilizing this tool. Finally, we emphasize the importance of future participation of myrmecologists to improve the database and use it to identify and fill holes in our knowledge of ant biodiversity.published_or_final_versio
Severity of cardiomyopathy associated with adenine nucleotide translocator-1 deficiency correlates with mtDNA haplogroup
Mutations of both nuclear and mitochondrial DNA (mtDNA)-encoded mitochondrial proteins can cause cardiomyopathy associated with mitochondrial dysfunction. Hence, the cardiac phenotype of nuclear DNA mitochondrial mutations might be modulated by mtDNA variation. We studied a 13-generation Mennonite pedigree with autosomal recessive myopathy and cardiomyopathy due to an SLC25A4 frameshift null mutation (c.523delC, p.Q175RfsX38), which codes for the heart-muscle isoform of the adenine nucleotide translocator-1. Ten homozygous null (adenine nucleotide translocator-1(-/-)) patients monitored over a median of 6 years had a phenotype of progressive myocardial thickening, hyperalaninemia, lactic acidosis, exercise intolerance, and persistent adrenergic activation. Electrocardiography and echocardiography with velocity vector imaging revealed abnormal contractile mechanics, myocardial repolarization abnormalities, and impaired left ventricular relaxation. End-stage heart disease was characterized by massive, symmetric, concentric cardiac hypertrophy; widespread cardiomyocyte degeneration; overabundant and structurally abnormal mitochondria; extensive subendocardial interstitial fibrosis; and marked hypertrophy of arteriolar smooth muscle. Substantial variability in the progression and severity of heart disease segregated with maternal lineage, and sequencing of mtDNA from five maternal lineages revealed two major European haplogroups, U and H. Patients with the haplogroup U mtDNAs had more rapid and severe cardiomyopathy than those with haplogroup H
Theoretical polarization dependence of the two-phonon double-resonant Raman spectra of graphene
The experimental Raman spectra of graphene exhibit a few intense two-phonon
bands, which are enhanced through double-resonant scattering processes. Though
there are many theoretical papers on this topic, none of them predicts the
spectra within a single model. Here, we present results for the two-phonon
Raman spectra of graphene calculated by means of the quantum perturbation
theory. The electron and phonon dispersions, electronic lifetime,
electron-photon and electron-phonon matrix elements, are all obtained within a
density-functional-theory-based non-orthogonal tight-binding model. We study
systematically the overtone and combination two-phonon Raman bands, and, in
particular, the energy and polarization dependence of their Raman shift and
intensity. We find that the ratio of the integrated intensities for parallel
and cross polarized light for all two-phonon bands is between 0.33 and 0.42.
Our results are in good agreement with the available experimental data
A heterotrimeric G protein, G alpha i-3, on Golgi membranes regulates the secretion of a heparan sulfate proteoglycan in LLC-PK1 epithelial cells
A heterotrimeric G-alpha-i subunit, alpha-i-3, is localized on Golgi membranes in LLC-PK1 and NRK epithelial cells where it colocalizes with mannosidase II by immunofluorescence. The alpha-i-3 was found to be localized on the cytoplasmic face of Golgi cisternae and it was distributed across the whole Golgi stack. The alpha-i-3 subunit is found on isolated rat liver Golgi membranes by Western blotting and G-alpha-i-3 on the Golgi apparatus is ADP ribosylated by pertussis toxin. LLC-PK1 cells were stably transfected with G-alpha-i-3 on an MT-1, inducible promoter in order to overexpress alpha-i-3 on Golgi membranes. The intracellular processing and constitutive secretion of the basement membrane heparan sulfate proteoglycan (HSPG) was measured in LLC-PK1 cells. Overexpression of alpha-i-3 on Golgi membranes in transfected cells retarded the secretion of HSPG and accumulated precursors in the medial-trans-Golgi. This effect was reversed by treatment of cells with pertussis toxin which results in ADP-ribosylation and functional uncoupling of G-alpha-i-3 on Golgi membranes. These results provide evidence for a novel role for the pertussis toxin sensitive G-alpha-i-3 protein in Golgi trafficking of a constitutively secreted protein in epithelial cells
Identification of a 200-kD, brefeldin-sensitive protein on Golgi membranes
A mAb AD7, raised against canine liver Golgi membranes, recognizes a novel, 200-kD protein (p200) which is found in a wide variety of cultured cell lines. Immunofluorescence staining of cultured cells with the AD7 antibody produced intense staining of p200 in the juxtanuclear Golgi complex and more diffuse staining of p200 in the cytoplasm. The p200 protein in the Golgi complex was colocalized with other Golgi proteins, including mannosidase II and beta-COP, a coatomer protein. Localization of p200 by immunoperoxidase staining at the electron microscopic level revealed concentrations of p200 at the dilated rims of Golgi cisternae. Biochemical studies showed that p200 is a peripheral membrane protein which partitions to the aqueous phase of Triton X-114 solutions and is phosphorylated. The p200 protein is located on the cytoplasmic face of membranes, since it was accessible to trypsin digestion in microsomal preparations. and is recovered in approximately equal amounts in membrane pellets and in the cytosol of homogenized cells. Immunofluorescence staining of normal rat kidney cells exposed to the toxin brefeldin A (BFA), showed that there was very rapid redistribution of p200, which was dissociated from Golgi membranes in the presence of this drug. The effect of BFA was reversible, since upon removal of the toxin, AD7 rapidly reassociated with the Golgi complex. In the BFA-resistant cell line PtK1, BFA failed to cause redistribution of p200 from Golgi membranes. Taken together, these results indicate that the p200 Golgi membrane-associated protein has many properties in common with the coatomer protein, beta-COP
Open radial artery harvesting better preserves endothelial function compared to the endoscopic approach
OBJECTIVES: Both the open and endovascular techniques are commonly used for harvesting the radial artery (ORAH and ERAH, respectively), and yet, very little is known about the effects of these 2 techniques on endothelial integrity and function of the radial artery (RA). The aim of this study was to assess the endothelial integrity and function of RA harvested using the 2 approaches. METHODS: Two independent surgical teams working in the same institution routinely use the RA for coronary artery bypass grafting exclusively employing either ORAH or ERAH. Thirty-nine consecutive patients were enrolled in this comparative study. Endothelial function after ORAH or ERAH was assessed by using the wire myograph system. The integrity of the RA endothelium was evaluated by immunohistochemical staining for erythroblast transformation specific-related gene. RESULTS: The vasodilation in response to acetylcholine was significantly higher in RA harvested with ORAH (P ≤ 0.001 versus ERAH). Endothelial integrity was not different between the 2 groups. CONCLUSIONS: ORAH is associated with a significantly higher endothelium-dependent vasodilation. Further investigation on the potential implications of these findings in terms of graft spasm and patency as well as clinical outcomes are needed
Ultrasensitivity of the Bacillus subtilis sporulation decision
Starving Bacillus subtilis cells execute a gene expression program
resulting in the formation of stress-resistant spores. Sporulation
master regulator, Spo0A, is activated by a phosphorelay and controls
the expression of a multitude of genes, including the forespore-
specific sigma factor σF and the mother cell-specific sigma
factor σE. Identification of the system-level mechanism of the sporulation
decision is hindered by a lack of direct control over Spo0A
activity. This limitation can be overcome by using a synthetic system
in which Spo0A activation is controlled by inducing expression
of phosphorelay kinase KinA. This induction results in a switch-like
increase in the number of sporulating cells at a threshold of KinA.
Using a combination of mathematical modeling and single-cell microscopy,
we investigate the origin and physiological significance
of this ultrasensitive threshold. The results indicate that the phosphorelay
is unable to achieve a sufficiently fast and ultrasensitive
response via its positive feedback architecture, suggesting that the
sporulation decision is made downstream. In contrast, activation
of σF in the forespore and of σE in the mother cell compartments
occurs via a cascade of coherent feed-forward loops, and thereby
can produce fast and ultrasensitive responses as a result of KinA
induction. Unlike σF activation, σE activation in the mother cell
compartment only occurs above the KinA threshold, resulting in
completion of sporulation. Thus, ultrasensitive σE activation explains
the KinA threshold for sporulation induction. We therefore infer
that under uncertain conditions, cells initiate sporulation but postpone
making the sporulation decision to average stochastic fluctuations
and to achieve a robust population response
Neuromuscular Complications With SARS-COV-2 Infection: A Review
© Copyright © 2020 Katyal, Narula, Acharya and Govindarajan. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cases were first reported in Wuhan, Hubei province of China in December, 2019. SARS- COV-2 primarily affects the cardio-respiratory system. Over the last few months, several studies have described various neurological sequelae of SARS-COV-2 infection. Neurological complications are more frequent in patients with severe respiratory infections. In this review, we have analyzed the current literature on neuromuscular complications associated with SARS-COV-2 and highlighted possible mechanisms of neuromuscular invasion. We reviewed 11 studies describing 11 cases of Guillain Barre syndrome (GBS), and 1 case each of Miller Fisher syndrome, Polyneuritis Cranialis, Acute myelitis, Oculomotor paralysis and Bell\u27s Palsy associated with SARS-COV-2 infection. Mean age of patients with GBS was 61.54 years, with standard deviation (SD) 14.18 years. Majority patients had fever and cough as the first symptom of SARS COV-2 infection. Mean time for onset of neurological symptoms from initial symptoms in 11 patients was 8.18 days, with SD of 2.86 days. Mean time to performing electrodiagnostic study from onset of neurological symptom was 6 days with standard deviation of 3.25. Six patients had demyelinating pattern, three had acute sensory motor axonal neuropathy, and one had acute motor axonal neuropathy on electrodiagnostic studies
Role of root exudates in plant-microbe interactions
The interactions in the rhizosphere are leading to a highly structured microbial community which, to a great deal, is influenced by the root exudates of plant origin. In this review, we have included the different types of interaction with special regard to the root exudates’ function in such positive or negative interactions beween plants and both bacterial and fungal partners of the plant in the rhizosphere, including mycorrhiza, nitrogen-fixing symbionts, plant growth promoting rhizobacteria endophytes and biological control organisms as well as allelopathy, antimicrobial effects and effects on nematodes. The differences in root exudates induced by microbial associations, role of quorum sensing in structuring communitites and effect on biogeochemical cycles are reviewed. The focus is put on agricultural systems and implications for ecosystems on arable land are drawn
What lies between market and hierarchy? Insights from internalization theory and global value chain theory
In this paper, we suggest that internalization theory might be extended by incorporating complementary insights from GVC theory. More specifically, we argue that internalization theory can explain why lead firms might wish to externalize selected activities, but that it is largely silent on the mechanisms by which those lead firms might exercise control over the resultant externalized relationships with their GVC partners. We advance an explanation linking the choice of control mechanism to two factors: power asymmetries between the lead firms and their GVC partners, and the degree of codifiability of the information to be exchanged in the relationship
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