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81.
The changing structure of the cuticle of the arthropod pentastomid parasite Porocephalus crotali, during growth to the infective stage in mouse and rattlesnake hosts, is described. The outermost cuticulin layer of the cuticle in instars II-VI is elevated to form a dense mat of epicuticular hairs. Since the VI larval cuticle is retained by the infective (VII) nymph as a protective sheath, effectively all stages in mice present a hairy surface to the host and this may constitute a physical barrier to inflammatory cells. The entire surface is overlain by a triple-track 'unit' membrane whose biophysical properties resemble those of a conventional plasma membrane, and there is evidence to suggest that this membrane is susceptible to immune attack. Under natural circumstances, epicuticular hairs entrap secretion, delivered to the cuticle via innumerable minute ducts which communicate with tegumental secretory cells termed subparietal cells (SPC). SPC synthesize lamellate droplets which unfold on the cuticle to constitute a layer of protective polymorphic vesicles. By contrast, infective nymphs in snakes possess a smooth cuticle and SPC membranous secretion is stacked over the entire surface, in sheets up to 20 deep. The function of the lipid and protein components of SPC secretion is discussed. 相似文献
82.
83.
Rayburn LY Gooding HC Choksi SP Maloney D Kidd AR Siekhaus DE Bender M 《Genetics》2003,163(1):227-237
Biosynthesis of most peptide hormones and neuropeptides requires proteolytic excision of the active peptide from inactive proprotein precursors, an activity carried out by subtilisin-like proprotein convertases (SPCs) in constitutive or regulated secretory pathways. The Drosophila amontillado (amon) gene encodes a homolog of the mammalian PC2 protein, an SPC that functions in the regulated secretory pathway in neuroendocrine tissues. We have identified amon mutants by isolating ethylmethanesulfonate (EMS)-induced lethal and visible mutations that define two complementation groups in the amon interval at 97D1 of the third chromosome. DNA sequencing identified the amon complementation group and the DNA sequence change for each of the nine amon alleles isolated. amon mutants display partial embryonic lethality, are defective in larval growth, and arrest during the first to second instar larval molt. Mutant larvae can be rescued by heat-shock-induced expression of the amon protein. Rescued larvae arrest at the subsequent larval molt, suggesting that amon is also required for the second to third instar larval molt. Our data indicate that the amon proprotein convertase is required during embryogenesis and larval development in Drosophila and support the hypothesis that AMON acts to proteolytically process peptide hormones that regulate hatching, larval growth, and larval ecdysis. 相似文献
84.
Christopher G.Love Ambrose E.Andongabo Pierre W.C.Carion Christopher J.Rawlings Graham J.King 《植物学报(英文版)》2012,54(5):345-355
Associating phenotypic traits and quantitative trait loci (QTL) to causative regions of the underlying genome is a key goal in agricultural research.InterStoreDB is a suite of integrated databases designed to assist in this process.The individual databases are species independent and generic in design,providing access to curated datasets relating to plant populations,phenotypic traits,genetic maps,marker loci and QTL,with links to functional gene annotation and genomic sequence data.Each component database provides access to associated metadata,including data provenance and parameters used in analyses,thus providing users with information to evaluate the relative worth of any associations identified.The databases include CropStoreDB,for management of population,genetic map,QTL and trait measurement data,SeqStoreDB for sequence-related data and AlignStoreDB,which stores sequence alignment information,and allows navigation between genetic and genomic datasets.Genetic maps are visualized and compared using the CMAP tool,and functional annotation from sequenced genomes is provided via an EnsEMBL-based genome browser.This framework facilitates navigation of the multiple biological domains involved in genetics and genomics research in a transparent manner within a single portal.We demonstrate the value of InterStoreDB as a tool for Brassica research.InterStoreDB is available from:http://www.interstoredb.org 相似文献
85.
Joseph Tillotson Magdalena Kedzior Larissa Guimarães Alison B. Ross Tara L. Peters Andrew J. Ambrose Cody J. Schmidlin Donna D. Zhang Letícia V. Costa-Lotufo Abimael D. Rodríguez Jonathan H. Schatz Eli Chapman 《Bioorganic & medicinal chemistry letters》2017,27(17):4082-4085
Activation of translation initiation is a common trait of cancer cells. Formation of the heterotrimeric eukaryotic initiation factor F (eIF4F) complex is the rate-limiting step in 5′ m7GpppN cap-dependent translation. This trimeric complex includes the eIF4E cap binding protein, the eIF4G scaffolding protein, and the DEAD box RNA helicase eIF4A. eIF4A is an ATP-dependent helicase and because it is the only enzyme in the eIF4F complex, it has been shown to be a potential therapeutic target for a variety of malignancies. To this end, we have used a simple ATPase biochemical screen to survey several hundred marine and terrestrial derived natural products. Herein, we report the discovery of two natural products from marine sources, elisabatin A (1) and allolaurinterol (2), which show low µM inhibition of eIF4A ATPase activity. Enzymological analyses revealed 1 and 2 to be ATP-competitive, and cellular evaluations showed reasonable cytotoxicity against A549 (lung cancer) and MDA-MA-468 (breast cancer) cell lines. However, only compound 2 showed potent inhibition of helicase activity congruent with its ATPase inhibitory activity. 相似文献
86.
The SarA protein family of Staphylococcus aureus 总被引:1,自引:0,他引:1
Cheung AL Nishina KA Trotonda MP Tamber S 《The international journal of biochemistry & cell biology》2008,40(3):355-361
Staphylococcus aureus is widely appreciated as an opportunistic pathogen, primarily in hospital-related infections. However, recent reports indicate that S. aureus infections can now occur in other wise healthy individuals in the community setting. The success of this organism can be attributed to the large array of regulatory proteins, including the SarA protein family, used to respond to changing microenvironments. Sequence alignment and structural data reveal that the SarA protein family can be divided into three subfamilies: (1) single domain proteins; (2) double domain proteins; (3) MarR homologs. Structural studies have also demonstrated that SarA, SarR, SarS, MgrA and thus possibly all members of this protein family are winged helix proteins with minor variations. Mutagenesis studies of SarA disclose that the winged helix motifs are important for DNA binding and function. Recent progress concerning the functions and plausible mechanisms of regulation of SarA and its homologs are discussed. 相似文献
87.
88.
Widespread invasion of riparian ecosystems by the large bamboo-like grass Arundo donax L. has altered community structure and ecological function of streams in California. This study evaluated the influence of
wildfire on A. donax invasion by investigating its relative rate of reestablishment versus native riparian species after wildfire burned 300 ha
of riparian woodlands along the Santa Clara River in southern California in October 2003. Post-fire A. donax growth rates and productivity were compared to those of native woody riparian species in plots established before and after
the fire. Arundo donax resprouted within days after the fire and exhibited higher growth rates and productivity compared to native riparian plants.
Arundo donax grew 3–4 times faster than native woody riparian plants—up to a mean of 2.62 cm day−1—and reached up to 2.3 m in height less than 3 months after the fire. One year post-fire, A. donax density was nearly 20 times higher and productivity was 14–24 times higher than for native woody species. Three mechanisms—fire-adapted
phenology, high growth rate, and growth response to nutrient enrichment—appear to promote the preemption of native woody riparian
species by A. donax after fire. This greater dominance of A. donax after wildfire increased the susceptibility of riparian woodlands along the Santa Clara River to subsequent fire, potentially
creating an invasive plant-fire regime cycle. Moreover, A. donax infestations appear to have allowed the wildfire to cross the broad bed of the Santa Clara River from the north, allowing
thousands of acres of shrubland to the south to burn. 相似文献
89.
Mallory RM Malkin E Ambrose CS Bellamy T Shi L Yi T Jones T Kemble G Dubovsky F 《PloS one》2010,5(10):e13755
Background
The safety, tolerability, and immunogenicity of a monovalent intranasal 2009 A/H1N1 live attenuated influenza vaccine (LAIV) were evaluated in children and adults.Methods/Principal Findings
Two randomized, double-blind, placebo-controlled studies were completed in children (2–17 y) and adults (18–49 y). Subjects were assigned 4∶1 to receive 2 doses of H1N1 LAIV or placebo 28 days apart. The primary safety endpoint was fever ≥38.3°C during days 1–8 after the first dose; the primary immunogenicity endpoint was the proportion of subjects experiencing a postdose seroresponse. Solicited symptoms and adverse events were recorded for 14 days after each dose and safety data were collected for 180 days post-final dose. In total, 326 children (H1N1 LAIV, n = 261; placebo, n = 65) and 300 adults (H1N1 LAIV, n = 240; placebo, n = 60) were enrolled. After dose 1, fever ≥38.3°C occurred in 4 (1.5%) pediatric vaccine recipients and 1 (1.5%) placebo recipient (rate difference, 0%; 95% CI: –6.4%, 3.1%). No adults experienced fever following dose 1. Seroresponse rates in children (H1N1 LAIV vs. placebo) were 11.1% vs. 6.3% after dose 1 (rate difference, 4.8%; 95% CI: –9.6%, 13.8%) and 32.0% vs. 14.5% after dose 2 (rate difference, 17.5%; 95% CI: 5.5%, 27.1%). Seroresponse rates in adults were 6.1% vs. 0% (rate difference, 6.1%; 95% CI: –5.6%, 12.6%) and 14.9% vs. 5.6% (rate difference, 9.3%; 95% CI: –0.8%, 16.3%) after dose 1 and dose 2, respectively. Solicited symptoms after dose 1 (H1N1 LAIV vs. placebo) occurred in 37.5% vs. 32.3% of children and 41.7% vs. 31.7% of adults. Solicited symptoms occurred less frequently after dose 2 in adults and children. No vaccine-related serious adverse events occurred.Conclusions/Significance
In subjects aged 2 to 49 years, two doses of H1N1 LAIV have a safety and immunogenicity profile similar to other previously studied and efficacious formulations of seasonal trivalent LAIV.Trial Registration
ClinicalTrials.gov , NCT00946101 NCT00945893相似文献90.