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81.
82.
Thaler CD Kuo RC Patton C Preston CM Yagisawa H Epel D 《Development, growth & differentiation》2004,46(5):413-423
Fertilization elicits a dramatic, transient rise in Ca2+ within the egg which is an essential component of egg activation and consequent initiation of development. In the sea urchin egg, three distinct Ca2+ stores have been identified which could, either individually or in combination, initiate Ca2+ release at fertilization. Inositol 1,4,5-trisphosphate (IP3) production by phospholipase C (PLC) has been suggested as the singular signal in initiating the Ca2+ transient. Other studies indicate that Ca2+ stores gated by cyclic adenosine diphosphate ribose (cADPR) or nicotinic acid adenine dinucleotide phosphate (NAADP) are also necessary. We have examined the temporal relationship between the Ca2+ rise and IP3 production at fertilization in vivo within individual eggs using a green fluorescent protein (GFP) coupled to a pleckstrin homology (PH) domain that can detect changes in IP3. Translocation of the probe occurred after the Ca2+ rise was initiated. Earlier, and possibly smaller, IP3 changes could not be excluded due to limitations in probe sensitivity. High IP3 levels are maintained during the decline in cytoplasmic Ca2+, suggesting that later IP3 metabolism might not be related to regulation of Ca2+, but may function to modulate other PIP2 regulated events such as actin polymerization or reflect other novel phosphoinositide signaling pathways. 相似文献
83.
Pinto MA Rubink WL Coulson RN Patton JC Johnston JS 《Evolution; international journal of organic evolution》2004,58(5):1047-1055
The invasion of Africanized honeybees (Apis mellifera L.) in the Americas provides a window of opportunity to study the dynamics of secondary contact of subspecies of bees that evolved in allopatry in ecologically distinctive habitats of the Old World. We report here the results of an 11-year mitochondrial DNA survey of a feral honeybee population from southern United States (Texas). The mitochondrial haplotype (mitotype) frequencies changed radically during the 11-year study period. Prior to immigration of Africanized honeybees, the resident population was essentially of eastern and western European maternal ancestry. Three years after detection of the first Africanized swarm there was a mitotype turnover in the population from predominantly eastern European to predominantly A. m. scutellata (ancestor of Africanized honeybees). This remarkable change in the mitotype composition coincided with arrival of the parasitic mite Varroa destructor, which was likely responsible for severe losses experienced by colonies of European ancestry. From 1997 onward the population stabilized with most colonies of A. m. scutellata maternal origin. 相似文献
84.
Rotavirus replication: plus-sense templates for double-stranded RNA synthesis are made in viroplasms
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Rotavirus plus-strand RNAs not only direct protein synthesis but also serve as templates for the synthesis of the segmented double-stranded RNA (dsRNA) genome. In this study, we identified short-interfering RNAs (siRNAs) for viral genes 5, 8, and 9 that suppressed the expression of NSP1, a nonessential protein; NSP2, a component of viral replication factories (viroplasms); and VP7, an outer capsid protein, respectively. The loss of NSP2 expression inhibited viroplasm formation, genome replication, virion assembly, and synthesis of the other viral proteins. In contrast, the loss of VP7 expression had no effect on genome replication; instead, it inhibited only outer-capsid morphogenesis. Similarly, neither genome replication nor any other event of the viral life cycle was affected by the loss of NSP1. The data indicate that plus-strand RNAs templating dsRNA synthesis within viroplasms are not susceptible to siRNA-induced RNase degradation. In contrast, plus-strand RNAs templating protein synthesis in the cytosol are susceptible to degradation and thus are not the likely source of plus-strand RNAs for dsRNA synthesis in viroplasms. Indeed, immunofluorescence analysis of bromouridine (BrU)-labeled RNA made in infected cells provided evidence that plus-strand RNAs are synthesized within viroplasms. Furthermore, transfection of BrU-labeled viral plus-strand RNA into infected cells suggested that plus-strand RNAs introduced into the cytosol do not localize to viroplasms. From these results, we propose that plus-strand RNAs synthesized within viroplasms are the primary source of templates for genome replication and that trafficking pathways do not exist within the cytosol that transport plus-strand RNAs to viroplasms. The lack of such pathways confounds the development of reverse genetics systems for rotavirus. 相似文献
85.
86.
Kristen M. Guglielmi Sarah M. McDonald John T. Patton 《The Journal of biological chemistry》2010,285(24):18123-18128
Rotaviruses perform the remarkable tasks of transcribing and replicating 11 distinct double-stranded RNA genome segments within the confines of a subviral particle. Multiple viral polymerases are tethered to the interior of a particle, each dedicated to a solitary genome segment but acting in synchrony to synthesize RNA. Although the rotavirus polymerase specifically recognizes RNA templates in the absence of other proteins, its enzymatic activity is contingent upon interaction with the viral capsid. This intraparticle strategy of RNA synthesis helps orchestrate the concerted packaging and replication of the viral genome. Here, we review our current understanding of rotavirus RNA synthetic mechanisms. 相似文献
87.
Relationships of Exodontiella, a non-alysiine, exodont member of the family Braconidae (Insecta, Hymenoptera) 总被引:1,自引:0,他引:1
Robert A. Wharton Matthew J. Yoder Joseph J. Gillespie John C. Patton & Rodney L. Honeycutt 《Zoologica scripta》2006,35(4):323-340
The placement of Exodontiella Wharton is re-examined in light of the discovery of four additional individuals. Genomic DNA was extracted from one of the individuals, the D2 expansion segment of the 28S rRNA gene was sequenced, and the sequence compared to selected taxa within the Braconidae. Based on the molecular data and the morphological study, Exodontiella is formally transferred from the Opiinae to the Gnamptodontinae. The genus and its included species are redescribed. 相似文献
88.
During the past two years, the performance of fluorescence-based protein detection methods has demonstrably eclipsed conventional technologies such as colloidal Coomassie Blue and silver staining with respect to detection sensitivity, quantitative accuracy and compatibility with modern protein identification and characterization procedures. At this point, fluorescence-based methods are poised to offer unprecedented new capabilities in proteomics investigations through the performance of multi-parameter quantitative measurements. The feasibility of such measurements has already been demonstrated through the specific detection of antibiotic-binding proteins, drug-metabolizing enzymes or post-translationally glycosylated proteins, along with the total protein expression profile from electrophoretically separated, complex biological specimens. 相似文献
89.
doi: 10.1111/j.1741‐2358.2011.00504.x Relationship between oral impacts on daily performance and chewing ability among independent elders residing in Daejeon City, Korea Objective: The aim of this study was to assess the association between oral health‐related quality of life (OHRQoL) measured by the oral impacts on daily performances (OIDP) inventory and chewing ability. Methods: The cluster sampling method was used to select a sample of 634 socially active independent community‐dwelling elders. An oral examination was conducted and a questionnaire was implemented. After bivariate comparisons, a multivariable two‐level logistic model was developed for the dichotomous OIDP indicator using the generalised linear mixed model. Results: The mean age of the participants was 74 years and 56.6% were women. Eight percent were edentulous, and the mean number of teeth was 17.7. Overall, 39.3% of participants had one or more oral impacts on daily performance. Elders with chewing ability of 0–49, 50–74 and 75–99% were approximately 120, 20 and seven times more likely to have oral impacts compared with those with full chewing ability, respectively. Elders reporting their oral health as ‘fair’ or ‘better’ were 68% less likely to have oral impacts than those with poor or very poor self‐reported oral health. Conclusion: Among independent elders, amelioration of chewing ability including delivery of appropriate prosthodontic care might independently contribute to improving OHRQoL of elders by improving their physical, psychological and social wellbeing. 相似文献
90.
M Alexandre AK Uduman S Minervini A Raoof CA Shugrue EO Akinbiyi V Patel M Shitia TR Kolodecik R Patton FS Gorelick EC Thrower 《American journal of physiology. Gastrointestinal and liver physiology》2012,303(6):G696-G704
Clinical studies indicate that cigarette smoking increases the risk for developing acute pancreatitis. The nicotine metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a major cigarette smoke toxin. We hypothesized that NNK could sensitize to pancreatitis and examined its effects in isolated rat pancreatic acini and in vivo. In acini, 100 nM NNK caused three- and fivefold activation of trypsinogen and chymotrypsinogen, respectively, above control. Furthermore, NNK pretreatment in acini enhanced zymogen activation in a cerulein pancreatitis model. The long-term effects of NNK were examined in vivo after intraperitoneal injection of NNK (100 mg/kg body wt) three times weekly for 2 wk. NNK alone caused zymogen activation (6-fold for trypsinogen and 2-fold for chymotrypsinogen vs. control), vacuolization, pyknotic nuclei, and edema. This NNK pretreatment followed by treatment with cerulein (40 μg/kg) for 1 h to induce early pancreatitis responses enhanced trypsinogen and chymotrypsinogen activation, as well as other parameters of pancreatitis, compared with cerulein alone. Potential targets of NNK include nicotinic acetylcholine receptors and β-adrenergic receptors; mRNA for both receptor types was detected in acinar cell preparations. Studies with pharmacological inhibitors of these receptors indicate that NNK can mediate acinar cell responses through an nonneuronal α(7)-nicotinic acetylcholine receptor (α(7)-nAChR). These studies suggest that prolonged exposure to this tobacco toxin can cause pancreatitis and sensitize to disease. Therapies targeting NNK-mediated pathways may prove useful in treatment of smoking-related pancreatitis. 相似文献