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81.
Keiichi Okada Takami Satomura Akihiko Kinoshita Takao Horikoshi Koh Yasue Masaki Fukuda Akiyoshi Yamada 《Mycoscience》2011,52(1):59-64
In this study, two plots in a secondary and another two in planted Pinus densiflora stands were exposed to different forest treatments, and the ectomycorrhizal (EM) biomass and its ergosterol content was measured
for a year. The unmanaged plot in the secondary stand had greater EM biomass than those in any other plots. Whereas understory
cutting had less effect on EM biomass, litter and humus removal decreased pine EM biomass and its ergosterol content, suggesting
that such forest treatment alters EM biomass and its structure. 相似文献
82.
The metabolism of pregnenolone in subcellular fractions of the testes of the macaque (Macaca fascicularis) has been studied using capillary gas chromatography to characterize and quantify the metabolites, after their conversion into the O-methyloxime and/or trimethylsilyl ether derivatives. The microsomal incubations yielded the greatest quantities of metabolites, with lesser amounts in the mitochondrial fraction. The cytosolic fraction contained no significant quantity of metabolites after incubation, except for 5alpha-androst-16-en-3 beta-ol. This, and other odorous androst-16-enes, found in the microsomal fraction, are of particular interest in the context of animal communication because of their possible pheromonal role. Pregnenolone was converted into androst-5-ene-3 beta,17 beta-diol, androst-4-ene-3,17-dione and testosterone, suggesting that both classical pathways for testosterone synthesis were operating. Testosterone was further converted into 5 alpha-reduced androstanediols, especially in the microsomal fraction. 相似文献
83.
Analysis of recombinant DNA clones of the endogenous BALB/c murine leukemia virus WN1802N: variation in long terminal repeat length 总被引:1,自引:4,他引:1 下载免费PDF全文
L R Boone F E Myer D M Yang J O Kiggans C Koh R W Tennant W K Yang 《Journal of virology》1983,45(1):484-488
We analyzed 15 recombinant DNA clones of the unintegrated closed circular DNA intermediate of the BALB/c endogenous ecotropic murine leukemia virus WN1802N. Thirteen of these clones had an insert which corresponded to the complete murine leukemia virus genome. Of these, six contained a single long terminal repeat (LTR) and seven contained two LTRs. The viral genomes in nine clones had an LTR of 520 base pairs (bp), one had an LTR of 570 bp, three had an LTR of 600 bp, and one had an LTR of 670 bp. Restriction endonuclease analysis demonstrated that the size variability resides in the U3 region. Seven of eight clones which yielded infectious virus by DNA transfection had the 520-bp LTR, and the other had a 600-bp LTR. More detailed examination of plasmid subclones of three isolates with different-sized LTRs revealed that the approximate position which varies in the U3 region corresponds to the 72-bp repeat region of Moloney sarcoma virus. Possible consequences of these variations are discussed. 相似文献
84.
Reversal of Fv-1 host range by in vitro restriction endonuclease fragment exchange between molecular clones of N-tropic and B-tropic murine leukemia virus genomes. 下载免费PDF全文
L R Boone F E Myer D M Yang C Y Ou C K Koh L E Roberson R W Tennant W K Yang 《Journal of virology》1983,48(1):110-119
We molecularly cloned unintegrated viral DNA of the BALB/c endogenous N-tropic and B-tropic murine leukemia retroviruses and in vitro passaged N-tropic Gross (passage A) murine leukemia retroviruses. Recombinant genomes were constructed in vitro by exchanging homologous restriction enzyme fragments from N- or B-tropic parents and subsequent recloning. Infectious virus was recovered after transfection of these recombinant genomes into NIH-3T3 cells and cocultivation with the Fv-1 nonrestrictive SC-1 cells. XC plaque assays of recombinant virus progeny on Fv-ln and Fv-lb cells indicated that the Fv-l host range was determined by sequences located between the BamHI site in the p30 region of the gag gene (1.6 kilobase pairs from the left end of the map) and the HindIII site located in the pol gene (2.9 kilobase pairs from the left end of the map). 相似文献
85.
86.
Fong Ping Chong Khuen Yen Ng Rhun Yian Koh Soi Moi Chye 《Cellular and molecular neurobiology》2018,38(5):965-980
Alzheimer’s disease (AD) is characterized by progressive memory loss and cognitive function deficits. There are two major pathological hallmarks that contribute to the pathogenesis of AD which are the presence of extracellular amyloid plaques composed of amyloid-β (Aβ) and intracellular neurofibrillary tangles composed of hyperphosphorylated tau. Despite extensive research that has been done on Aβ in the last two decades, therapies targeting Aβ were not very fruitful at treating AD as the efficacy of Aβ therapies observed in animal models is not reflected in human clinical trials. Hence, tau-directed therapies have received tremendous attention as the potential treatments for AD. Tauopathies are closely correlated with dementia and immunotherapy has been effective at reducing tau pathology and improving cognitive deficits in animal models. Thus, in this review article, we discussed the pathological mechanism of tau proteins, the key factors contributing to tauopathies, and therapeutic approaches for tauopathies in AD based on the recent progress in tau-based research. 相似文献
87.
Hyun Jung Jho Yeol Kim Kyung Ae Kong Dae Hyun Kim Jin Young Choi Eun Jeong Nam Jin Young Choi Sujin Koh Kwan Ok Hwang Sun Kyung Baek Eun Jung Park 《PloS one》2014,9(8)
Purpose
Medical professionals’ practices and knowledge regarding cancer pain management have often been cited as inadequate. This study aimed to evaluate knowledge, practices and perceived barriers regarding cancer pain management among physicians and nurses in Korea.Methods
A nationwide questionnaire survey was administered to physicians and nurses involved in the care of cancer patients. Questionnaire items covered pain assessment and documentation practices, knowledge regarding cancer pain management, the perceived barriers to cancer pain control, and processes perceived as the major causes of delay in opioid administration.Results
A total of 333 questionnaires (149 physicians and 284 nurses) were analyzed. Nurses performed pain assessment and documentation more regularly than physicians did. Although physicians had better knowledge of pain management than did nurses, both groups lacked knowledge regarding the side effects and pharmacology of opioids. Physicians working in the palliative care ward and nurses who had received pain management education obtained higher scores on knowledge. Physicians perceived patients’ reluctance to take opioids as a barrier to pain control, more so than did nurses, while nurses perceived patients’ tendency to under-report of pain as a barrier, more so than did physicians. Physicians and nurses held different perceptions regarding major cause of delay during opioid administration.Conclusions
There were differences between physicians and nurses in knowledge and practices for cancer pain management. An effective educational strategy for cancer pain management is needed in order to improve medical professionals’ knowledge and clinical practices. 相似文献88.
Yanqun Liu Min Hoe Chew Xue Wei Goh Soo Yong Tan Carol Tien Tau Loi Yuen Ming Tan Hai Yang Law Poh Koon Koh Choong Leong Tang 《PloS one》2014,9(4)
Background
Germline defects of mismatch repair (MMR) genes underlie Lynch Syndrome (LS). We aimed to gain comprehensive genetic and epigenetic profiles of LS families in Singapore, which will facilitate efficient molecular diagnosis of LS in Singapore and the region.Methods
Fifty nine unrelated families were studied. Mutations in exons, splice-site junctions and promoters of five MMR genes were scanned by high resolution melting assay followed by DNA sequencing, large fragment deletions/duplications and promoter methylation in MLH1, MSH2, MSH6 and PMS2 were evaluated by multiplex ligation-dependent probe amplification. Tumor microsatellite instability (MSI) was assessed with five mononucleotide markers and immunohistochemical staining (IHC) was also performed.Results
Pathogenic defects, all confined to MLH1 and MSH2, were identified in 17 out of 59 (28.8%) families. The mutational spectrum was highly heterogeneous and 28 novel variants were identified. One recurrent mutation in MLH1 (c.793C>T) was also observed. 92.9% sensitivity for indication of germline mutations conferred by IHC surpassed 64.3% sensitivity by MSI. Furthermore, 15.6% patients with MSS tumors harbored pathogenic mutations.Conclusions
Among major ethnic groups in Singapore, all pathogenic germline defects were confined to MLH1 and MSH2. Caution should be applied when the Amsterdam criteria and consensus microsatellite marker panel recommended in the revised Bethesda guidelines are applied to the local context. We recommend a screening strategy for the local LS by starting with tumor IHC and the hotspot mutation testing at MLH1 c.793C>T followed by comprehensive mutation scanning in MLH1 and MSH2 prior to proceeding to other MMR genes. 相似文献89.
Clara K. Chow Daniel J. Corsi Karen Lock Manisha Madhavan Pam Mackie Wei Li Sun Yi Yang Wang Sumathi Swaminathan Patricio Lopez-Jaramillo Diego Gomez-Arbelaez álvaro Avezum Scott A. Lear Gilles Dagenais Koon Teo Martin McKee Salim Yusuf 《PloS one》2014,9(11)
Background
Previous research has shown that environments with features that encourage walking are associated with increased physical activity. Existing methods to assess the built environment using geographical information systems (GIS) data, direct audit or large surveys of the residents face constraints, such as data availability and comparability, when used to study communities in countries in diverse parts of the world. The aim of this study was to develop a method to evaluate features of the built environment of communities using a standard set of photos. In this report we describe the method of photo collection, photo analysis instrument development and inter-rater reliability of the instrument.Methods/Principal Findings
A minimum of 5 photos were taken per community in 86 communities in 5 countries according to a standard set of instructions from a designated central point of each community by researchers at each site. A standard pro forma derived from reviewing existing instruments to assess the built environment was developed and used to score the characteristics of each community. Photo sets from each community were assessed independently by three observers in the central research office according to the pro forma and the inter-rater reliability was compared by intra-class correlation (ICC). Overall 87% (53 of 60) items had an ICC of ≥0.70, 7% (4 of 60) had an ICC between 0.60 and 0.70 and 5% (3 of 60) items had an ICC ≤0.50.Conclusions/Significance
Analysis of photos using a standardized protocol as described in this study offers a means to obtain reliable and reproducible information on the built environment in communities in very diverse locations around the world. The collection of the photographic data required minimal training and the analysis demonstrated high reliability for the majority of items of interest. 相似文献90.
Identifying adaptively important loci in recently bottlenecked populations – be it natural selection acting on a population following the colonization of novel habitats in the wild, or artificial selection during the domestication of a breed – remains a major challenge. Here we report the results of a simulation study examining the performance of available population-genetic tools for identifying genomic regions under selection. To illustrate our findings, we examined the interplay between selection and demography in two species of Peromyscus mice, for which we have independent evidence of selection acting on phenotype as well as functional evidence identifying the underlying genotype. With this unusual information, we tested whether population-genetic-based approaches could have been utilized to identify the adaptive locus. Contrary to published claims, we conclude that the use of the background site frequency spectrum as a null model is largely ineffective in bottlenecked populations. Results are quantified both for site frequency spectrum and linkage disequilibrium-based predictions, and are found to hold true across a large parameter space that encompasses many species and populations currently under study. These results suggest that the genomic footprint left by selection on both new and standing variation in strongly bottlenecked populations will be difficult, if not impossible, to find using current approaches. 相似文献