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991.
992.
Nelson-Rees Walter A. Kniazeff Alexis J. Malley Roberta L. Darby Norman B. 《Chromosoma》1967,23(2):154-161
Somatic chromosomes of a female and male Himalayan thar, Hemitragus jemlahicus (H. Smith) are described. The diploid number is 48, there are 12 atelocentric and 34 telocentric autosomes in both sexes, the X-chromosome is meta- or submetacentric. The morphological appearance of the Y-chromosome is compared with that of other bovid species including recent observations on the goat Capra hircus.Supported by Contract No. PH 43-63-13 between the National Cancer Institute of the National Institutes of Health and the University of California. 相似文献
993.
Alexis Nazareno Campetelli Noelia Edith Monesterolo Gabriela Previtali Verónica Silvina Santander Marina Rafaela Amaiden Carlos Angel Arce Javier Valdez-Taubas César Horacio Casale 《Biochimica et Biophysica Acta (BBA)/General Subjects》2013
Background
Glucose induces H+-ATPase activation in Saccharomyces cerevisiae. Our previous study showed that (i) S. cerevisiae plasma membrane H+-ATPase forms a complex with acetylated tubulin (AcTub), resulting in inhibition of the enzyme activity; (ii) exogenous glucose addition results in the dissociation of the complex and recovery of the enzyme activity.Methods
We used classic biochemical and molecular biology tools in order to identify the key components in the mechanism that leads to H+-ATPase activation after glucose treatment.Results
We demonstrate that glucose-induced dissociation of the complex is due to pH-dependent activation of a protease that hydrolyzes membrane tubulin. Biochemical analysis identified a serine protease with a kDa of 35–40 and an isoelectric point between 8 and 9. Analysis of several knockout yeast strains led to the detection of Lpx1p as the serine protease responsible of tubulin proteolysis. When lpx1Δ cells were treated with glucose, tubulin was not degraded, the AcTub/H+-ATPase complex did not undergo dissociation, and H+-ATPase activation was significantly delayed.Conclusion
Our findings indicate that the mechanism of H+-ATPase activation by glucose involves a decrease in the cytosolic pH and consequent activation of a serine protease that hydrolyzes AcTub, accelerating the process of the AcTub/H+-ATPase complex dissociation and the activation of the enzyme.General significance
Our data sheds light into the mechanism by which acetylated tubulin dissociates from the yeast H+-ATPase, identifying a degradative step that remained unknown. This finding also proposes an indirect way to pharmacologically regulate yeast H+-ATPase activity and open the question about mechanistic similarities with other higher eukaryotes. 相似文献994.
Alexis Guerin-Laguette Nicholas Cummings Nina Hesom-Williams Ruth Butler Yun Wang 《Mycorrhiza》2013,23(2):87-98
This study compiles the results from an examination of mycorrhizae on root samples from Tuber melanosporum truffières in New Zealand. Samples were taken over 5 years from 328 trees in 43 truffières established with nursery-inoculated trees. Mycorrhizae were analysed using a combination of morphological and molecular techniques, focusing on the identification of Tuber species. Results show that 49% of the trees, and nearly 90% of the truffières, retained T. melanosporum mycorrhizae up to 21 years after planting. Tuber mycorrhizae with spiky cystidia were found on 26.9% of the tested trees: Tuber brumale (5.5%), Tuber maculatum (10.7%), and unidentified Tuber species (10.7%), and were detected in 67% of the truffières tested. T. brumale was found in 28% and T. maculatum in 35% of the truffières. In 56% of the truffières, T. melanosporum was found to occur with spiky Tuber species. The existence of T. brumale and T. maculatum in the same truffière was recorded only once. Forty-four percent of trees examined had Scleroderma-like (SCL) mycorrhizae and 50% of trees hosted other ectomycorrhizal species (OE). For all categories of mycorrhizal species examined, the variation between truffières was greater than variation within each truffière. Overall results indicate that Corylus avellana tends to be more receptive to mycorrhizae of Tuber species than Quercus robur but is not necessarily more productive. In productive truffières, Q. robur appears to host SCL mycorrhizae more often than C. avellana. This is the first study of its scale to analyse the mycorrhizal species associated with T. melanosporum truffières in the Southern Hemisphere. 相似文献
995.
Benoit Maillot Nicolas Lévy Sylvia Eiler Corinne Crucifix Florence Granger Ludovic Richert Pascal Didier Julien Godet Karine Pradeau-Aubreton Stéphane Emiliani Alexis Nazabal Paul Lesbats Vincent Parissi Yves Mely Dino Moras Patrick Schultz Marc Ruff 《PloS one》2013,8(4)
Integration of the HIV-1 cDNA into the human genome is catalyzed by the viral integrase (IN) protein. Several studies have shown the importance of cellular cofactors that interact with integrase and affect viral integration and infectivity. In this study, we produced a stable complex between HIV-1 integrase, viral U5 DNA, the cellular cofactor LEDGF/p75 and the integrase binding domain of INI1 (INI1-IBD), a subunit of the SWI/SNF chromatin remodeling factor. The stoichiometry of the IN/LEDGF/INI1-IBD/DNA complex components was found to be 4/2/2/2 by mass spectrometry and Fluorescence Correlation Spectroscopy. Functional assays showed that INI1-IBD inhibits the 3′ processing reaction but does not interfere with specific viral DNA binding. Integration assays demonstrate that INI1-IBD decreases the amount of integration events but inhibits by-product formation such as donor/donor or linear full site integration molecules. Cryo-electron microscopy locates INI1-IBD within the cellular DNA binding site of the IN/LEDGF complex, constraining the highly flexible integrase in a stable conformation. Taken together, our results suggest that INI1 could stabilize the PIC in the host cell, by maintaining integrase in a stable constrained conformation which prevents non-specific interactions and auto integration on the route to its integration site within nucleosomes, while LEDGF organizes and stabilizes an active integrase tetramer suitable for specific vDNA integration. Moreover, our results provide the basis for a novel type of integrase inhibitor (conformational inhibitor) representing a potential new strategy for use in human therapy. 相似文献
996.
Georgia A. F. Ladbury Magda Gavana Kostas Danis Anna Papa Dimitris Papamichail Spiros Mourelatos Sandra Gewehr George Theocharopoulos Stefanos Bonovas Alexis Benos Takis Panagiotopoulos 《PloS one》2013,8(11)
Introduction
During summer 2010, 262 human cases including 35 deaths from West Nile virus (WNV) infection were reported from Central Macedonia, Greece. Evidence from mosquitoes, birds and blood donors demonstrated that the epidemic was caused by WNV lineage 2, which until recently was considered of low virulence. We conducted a household seroprevalence study to estimate the spread of infection in the population during the epidemic, ascertain the relationship of infection to clinical disease, and identify risk factors for infection.Methods
We used a two-stage cluster design to select a random sample of residents aged ≥18 years in the outbreak epicentre. We collected demographic, medical, and risk factor data using standard questionnaires and environmental checklists, and tested serum samples for presence of WNV IgG and IgM antibodies using ELISA.Results
Overall, 723 individuals participated in the study, and 644 blood samples were available. Weighted seropositivity for IgG antibodies was 5.8% (95% CI: 3.8–8.6; n=41). We estimated that about 1 in 130 (1:141 to 1:124) infected individuals developed WNV neuroinvasive disease, and approximately 18% had clinical manifestations attributable to their infection. Risk factors for infection reflected high exposure to mosquitoes; rural residents were particularly at risk (prevalence ratio: 8.2, 95% CI: 1.1–58.7).Discussion
This study adds to the evidence that WNV lineage 2 strains can cause significant illness, demonstrating ratios of infection to clinical disease similar to those found previously for WNV lineage 1. 相似文献997.
Elsa Kermorvant-Duchemin Alexis Christophe Pinel Sophie Lavalette Delphine Lenne William Raoul Bertrand Calippe Francine Behar-Cohen José-Alain Sahel Xavier Guillonneau Florian Sennlaub 《PloS one》2013,8(11)
Recent evidence suggests that transient hyperglycemia in extremely low birth weight infants is strongly associated with the occurrence of retinopathy of prematurity (ROP). We propose a new model of Neonatal Hyperglycemia-induced Retinopathy (NHIR) that mimics many aspects of retinopathy of prematurity. Hyperglycemia was induced in newborn rat pups by injection of streptozocine (STZ) at post natal day one (P1). At various time points, animals were assessed for vascular abnormalities, neuronal cell death and accumulation and activation of microglial cells. We here report that streptozotocin induced a rapid and sustained increase of glycemia from P2/3 to P6 without affecting rat pups gain weight or necessitating insulin treatment. Retinal vascular area was significantly reduced in P6 hyperglycemic animals compared to control animals. Hyperglycemia was associated with (i) CCL2 chemokine induction at P6, (ii) a significant recruitment of inflammatory macrophages and an increase in total number of Iba+ macrophages/microglia cells in the inner nuclear layer (INL), and (iii) excessive apoptosis in the INL. NHIR thereby reproduces several aspects of ischemic retinopathies, including ROP and diabetic retinopathies, and might be a useful model to decipher hyperglycemia-induced cellular and molecular mechanisms in the small rodent. 相似文献
998.
Félix Legendre Neal Cody Carole Iampietro Julie Bergalet Fabio Alexis Lefebvre Ga?l Moquin-Beaudry Olivia Zhang Xiaofeng Wang Eric Lécuyer 《Journal of visualized experiments : JoVE》2013,(71)
Assessing the expression pattern of a gene, as well as the subcellular localization properties of its transcribed RNA, are key features for understanding its biological function during development. RNA in situ hybridization (RNA-ISH) is a powerful method used for visualizing RNA distribution properties, be it at the organismal, cellular or subcellular levels 1. RNA-ISH is based on the hybridization of a labeled nucleic acid probe (e.g. antisense RNA, oligonucleotides) complementary to the sequence of an mRNA or a non-coding RNA target of interest 2. As the procedure requires primary sequence information alone to generate sequence-specific probes, it can be universally applied to a broad range of organisms and tissue specimens 3. Indeed, a number of large-scale ISH studies have been implemented to document gene expression and RNA localization dynamics in various model organisms, which has led to the establishment of important community resources 4-11. While a variety of probe labeling and detection strategies have been developed over the years, the combined usage of fluorescently-labeled detection reagents and enzymatic signal amplification steps offer significant enhancements in the sensitivity and resolution of the procedure 12. Here, we describe an optimized fluorescent in situ hybridization method (FISH) employing tyramide signal amplification (TSA) to visualize RNA expression and localization dynamics in staged Drosophila embryos. The procedure is carried out in 96-well PCR plate format, which greatly facilitates the simultaneous processing of large numbers of samples. 相似文献
999.
Gwendoline Gicquel Emeline Bouffartigues Manjeet Bains Virginie Oxaran Thibaut Rosay Olivier Lesouhaitier Nathalie Connil Alexis Bazire Olivier Maillot Magalie Bénard Pierre Cornelis Robert E. W. Hancock Alain Dufour Marc G. J. Feuilloley Nicole Orange Eric Déziel Sylvie Chevalier 《PloS one》2013,8(11)
1000.
Ixodes scapularis is the specific arthropod vector for a number of globally prevalent infections, including Lyme disease caused by the bacterium Borrelia burgdorferi. A feeding-induced and acellular epithelial barrier, known as the peritrophic membrane (PM) is detectable in I. scapularis. However, whether or how the PM influences the persistence of major tick-borne pathogens, such as B. burgdorferi, remains largely unknown. Mass spectrometry-based proteome analyses of isolated PM from fed ticks revealed that the membrane contains a few detectable proteins, including a predominant and immunogenic 60 kDa protein with homology to arthropod chitin deacetylase (CDA), herein termed I. scapularis
CDA-like protein or IsCDA. Although IsCDA is primarily expressed in the gut and induced early during tick feeding, its silencing via RNA interference failed to influence either the occurrence of the PM or spirochete persistence, suggesting a redundant role of IsCDA in tick biology and host-pathogen interaction. However, treatment of ticks with antibodies against IsCDA, one of the most predominant protein components of PM, affected B. burgdorferi survival, significantly augmenting pathogen levels within ticks but without influencing the levels of total gut bacteria. These studies suggested a preferential role of tick PM in limiting persistence of B. burgdorferi within the vector. Further understanding of the mechanisms by which vector components contribute to pathogen survival may help the development of new strategies to interfere with the infection. 相似文献