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921.
922.
Incidence of Candidatus Liberibacter asiaticus infection in abandoned citrus occurring in proximity to commercially managed groves 总被引:1,自引:0,他引:1
Tiwari S Lewis-Rosenblum H Pelz-Stelinski K Stelinski LL 《Journal of economic entomology》2010,103(6):1972-1978
Huanglongbing is one of the most devastating diseases of citrus (Citrus spp.). One management tactic against huanglongbing is aggressive management of the vector, the Asian citrus psyllid (Diaphorina citri Kuwayama), with insecticide applications. However, D. citri in abandoned groves are not controlled and therefore pose a risk of reinfestation for nearby commercial citrus. These abandoned groves could serve as a reservoir for the vector, as well as a source of the presumed causal agent for huanglongbing in Florida, Candidatus Liberibacter asiaticus (Las). The current study was conducted to determine the degree to which Las is present in abandoned Florida citrus groves and to compare relative inoculum levels in nearby managed and abandoned groves during times of the year when D. citri are abundant (June, July, and August). In addition, the movement of Las by dispersing D. citri adults from inner and edge rows of abandoned grove plots to the corresponding rows of managed plots was quantified during the same 3 mo. The results of the current study confirmed the presence of Las in both D. citri and plant tissue in abandoned groves at statistically equivalent levels to those in nearby managed groves. The mean number of D. citri adults dispersing from abandoned to managed grove plots ranged from 7.25 +/- 1.70 to 70.25 +/- 21.25 per 4-d intervals. Of those, the mean number of dispersing D. citri adults that were carrying the Las pathogen ranged from 1.00 +/- 0.58 to 1.50 +/- 0.50. Our results indicate that abandoned citrus groves are a significant source of Ca. Las and that dispersing D. citri move this pathogen into nearby managed groves. 相似文献
923.
Clonal derivatives of the RD-114 cell line differ in their antiviral and gene-inducing responses to interferons. 总被引:1,自引:1,他引:1 下载免费PDF全文
The human rhabdomyosarcoma cell line RD-114 is partially responsive to interferons (IFNs). In these cells, alpha interferon (IFN-alpha) or gamma interferon (IFN-gamma) inhibits the replication of some viruses but not of others. Similarly, some of the IFN-inducible mRNAs are induced poorly, whereas others are induced well. Here we report the isolation of clonal derivatives of this line which display different spectra of responses to IFNs. Among the eight extensively characterized clonal lines, one, C10, did not respond to IFN-alpha or IFN-gamma at all. Retrovirus production by each of the seven other lines was inhibited by both IFN-alpha and IFN-gamma. Replication of vesicular stomatitis virus was inhibited strongly by IFN-alpha in clone B1 but not in others, whereas it was not appreciably affected by IFN-gamma in any clone. Replication of encephalomyocarditis virus was inhibited strongly by IFN-gamma in clones A1, A2, A3, B3, and B8 and by IFN-alpha in clone A2. Neither IFN inhibited the multiplication of these clones greatly, although their doubling times were slightly increased. Five mRNAs were induced by IFNs to varying degrees in the seven clones. mRNA 2A was most strongly induced by IFN-gamma in clone A3. mRNA 1-8 was strongly induced by IFN-alpha in clone A1 and by either IFN in clones A2 and A3. The highest concentrations of 2',5'-oligoadenylate synthetase mRNA, mRNA 561, and mRNA 6-16 were in IFN-alpha-treated clones A1 and A2. These results demonstrated the existence of clonal heterogeneity in IFN responses in a cell line and strengthened the view that IFN treatment of cells generates multiple signals leading to a variety of IFN-induced phenotypes. 相似文献
924.
Synechocystis sp. PCC 6803 when grown in the presence of sublethal (M) levels of cobalt chloride shows an enhancement of Photosystem II (PS II) catalyzed Hill reaction. This stimulation seems to be induced by cobalt ions as other metal ions inhibit para-benzoquinone catalyzed Hill reaction. At saturating white light intensity, this enhancement is two times over that of the control cells on unit chlorophyll basis. Analysis of the PS II electron transport rate at varying intensities of white, blue or yellow light suggests an increased maximal rates but no change in the quantum yield or effective antenna size of CoCl2-grown cells. There were no structural and functional changes in the phycobilisome as judged by the absence of changes in the phycocyanin/allophycocyanin ratio, fluorescence emission spectra, second derivative absorption spectra at 77 K and SDS-PAGE analysis of isolated phycobilisomes. The 77 K fluorescence emission spectra of the cells showed a decrease in the ratio of Photosystem I emission (F725) to Photosystem II emission (F685) in CoCl2-grown cells compared to the control cells. These observations indicate three possibilities: (1) there is an increase in the number of Photosystem II units; (2) a faster turnover of Photosystem II centers; or (3) an alteration in energy redistribution between PS II and PS I in CoCl2-grown cells which causes stimulation of Photosystem II electron transport rate.Abbreviations APC
allophycocyanin
- Chl a
chlorophyll a
- DBMIB
2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone
- EDTA
ethylene diamine tetraacetic acid
- PBS
phycobilisome
- PC
phycocyanin
- PSI
Photosystem I
- PS II
Photosystem II
- pBQ
p-benzoquinone
- PMSF
phenyl methyl sulfonyl fluoride 相似文献
925.
Gupta Ankur Gadia Rohit Singh Ankit Singh Rajat Kumar Tiwari Akhilesh 《Plasmonics (Norwell, Mass.)》2022,17(1):143-151
Plasmonics - This paper dealt with the analysis of a surface plasmon resonance (SPR)-based D-shape photonic crystal fiber (PCF) biosensor for the detection of multimolecules present in a single... 相似文献
926.
927.
B. Joseph Elmunzer Rodney A. Hayward Philip S. Schoenfeld Sameer D. Saini Amar Deshpande Akbar K. Waljee 《PLoS medicine》2012,9(12)
Background
Randomized controlled trials (RCTs) have yielded varying estimates of the benefit of flexible sigmoidoscopy (FS) screening for colorectal cancer (CRC). Our objective was to more precisely estimate the effect of FS-based screening on the incidence and mortality of CRC by performing a meta-analysis of published RCTs.Methods and Findings
Medline and Embase databases were searched for eligible articles published between 1966 and 28 May 2012. After screening 3,319 citations and 29 potentially relevant articles, two reviewers identified five RCTs evaluating the effect of FS screening on the incidence and mortality of CRC. The reviewers independently extracted relevant data; discrepancies were resolved by consensus. The quality of included studies was assessed using criteria set out by the Evidence-Based Gastroenterology Steering Group. Random effects meta-analysis was performed.The five RCTs meeting eligibility criteria were determined to be of high methodologic quality and enrolled 416,159 total subjects. Four European studies compared FS to no screening and one study from the United States compared FS to usual care. By intention to treat analysis, FS-based screening was associated with an 18% relative risk reduction in the incidence of CRC (0.82, 95% CI 0.73–0.91, p<0.001, number needed to screen [NNS] to prevent one case of CRC = 361), a 33% reduction in the incidence of left-sided CRC (RR 0.67, 95% CI 0.59–0.76, p<0.001, NNS = 332), and a 28% reduction in the mortality of CRC (relative risk [RR] 0.72, 95% CI 0.65–0.80, p<0.001, NNS = 850). The efficacy estimate, the amount of benefit for those who actually adhered to the recommended treatment, suggested that FS screening reduced CRC incidence by 32% (p<0.001), and CRC-related mortality by 50% (p<0.001).Limitations of this meta-analysis include heterogeneity in the design of the included trials, absence of studies from Africa, Asia, or South America, and lack of studies comparing FS with colonoscopy or stool-based testing.Conclusions
This meta-analysis of randomized controlled trials demonstrates that FS-based screening significantly reduces the incidence and mortality of colorectal cancer in average-risk patients. Please see later in the article for the Editors'' Summary 相似文献928.
A study of heat effects was performed in thylakoids and photosystem II (PSII)-enriched membranes isolated from spinach in
relation to Cl−-induced activation of PSII catalyzed oxygen evolution and the retention of Cl− in the PSII complex. For this, Cl−-sufficient membranes and low-Cl− membranes were used. The presence of Cl− in the reaction medium did accelerate oxygen evolution, which remained unaffected by heat treatment up to 40°C in PSII membranes
and up to 42.5°C in thylakoids. Heat resistance of Cl−-induced activation of oxygen evolution was found to be independent of the presence of ‘bound Cl−’ in the preparations. However, the functional stability of the PSII complex during heat treatment showed a marked dependence
on the presence of bound Cl− in PSII. Electron paramagnetic resonance study of manganese (Mn) release per reaction center/YD+ showed that there was little loss of Mn2+ up to 42°C in our preparations, although the PSII activity was significantly lowered. These observations together with data
from steady state chlorophyll a fluorescence imply that the site of action of Cl− causing direct activation of oxygen evolution was different from the site of primary heat damage. A differential response
of chloride binding sites to heat stress was observed. The high-affinity (tightly bound, slow exchanging) site of chloride
is affected earlier (∼37°C) while low-affinity (loosely bound, fast exchanging) site gets affected at higher temperatures
(42.5°C in thylakoids and 40°C in the case of PSII-enriched membranes).
Prasanna Mohanty is an INSA Honorary Scientist and Professor on Courtesy, DAVV, Indore. 相似文献
929.
Serotonin(1A) receptors are important neurotransmitter receptors and belong to the superfamily of G-protein coupled receptors (GPCRs). Although it is an important drug target, the crystal structure of the serotonin(1A) receptor has not been solved yet. Earlier homology models of the serotonin(1A) receptor were generated using rhodopsin as a template. We have used two recent crystal structures of the human β(2)-adrenergic receptor, one of which shows specific cholesterol binding site(s), as templates to model the human serotonin(1A) receptor. Since the sequence similarity between the serotonin(1A) receptor and β(2)-adrenergic receptor is considerably higher than the similarity between the serotonin(1A) receptor and rhodopsin, our model is more reliable. Based on these templates, we generated models of the serotonin(1A) receptor in the absence and presence of cholesterol. The receptor model appears more compact in the presence of cholesterol. We validated the stability of 'compactness' using coarse-grain MD simulation. Importantly, all ligands exhibit higher binding energies when docked to the receptor in the presence of cholesterol, thereby implying that membrane cholesterol facilitates ligand binding to the serotonin(1A) receptor. To the best of our knowledge, this is one of the first reports in which lipid-specific receptor conformations have been modeled by homology modeling. 相似文献
930.
Rajoria S Suriano R George A Shanmugam A Schantz SP Geliebter J Tiwari RK 《PloS one》2011,6(1):e15879