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1.
Ito S Ihara T Tamura H Tanaka S Ikeda T Kajihara H Dissanayake C Abdel-Motaal FF El-Sayed MA 《FEBS letters》2007,581(17):3217-3222
The tomato saponin alpha-tomatine has been proposed to kill sensitive cells by binding to cell membranes followed by leakage of cell components. However, details of the modes of action of the compound on fungal cells are poorly understood. In the present study, mechanisms involved in alpha-tomatine-induced cell death of fungi were examined using a filamentous pathogenic fungus Fusarium oxysporum. alpha-Tomatine-induced cell death of F. oxysporum (TICDF) occurred only under aerobic conditions and was blocked by the mitochondrial F(0)F(1)-ATPase inhibitor oligomycin, the caspase inhibitor D-VAD-fmk, and protein synthesis inhibitor cycloheximide. Fungal cells exposed to alpha-tomatine showed TUNEL-positive nuclei, depolarization of transmembrane potential of mitochondria, and reactive oxygen species (ROS) accumulation. These results suggest that TICDF occurs through a programmed cell death process in which mitochondria play a pivotal role. Pharmacological studies using inhibitors suggest that alpha-tomatine activates phosphotyrosine kinase and monomeric G-protein signaling pathways leading to Ca(2+) elevation and ROS burst in F. oxysporum cells. 相似文献
2.
Jayasinghe L Mallika Kumarihamy BM Suranga Arundathie BG Dissanayake L Hara N Fujimoto Y 《Steroids》2003,68(5):447-450
Chemical investigation of ethyl acetate extract of the fruits of Diploclisia glaucescens of the family Menispermaceae furnished a new ecdysteroid 2-deoxy-5beta,20-dihydroxyecdysone, together with 20-hydroxyecdysone, 3-deoxy-1beta,20-dihydroxyecdysone, 2-deoxy-20-hydroxyecdysone, 24-ethyl-20-hydroxyecdysone (makisterone C). Latter two ecdysteroids are reported first time from the family Menispermaceae. 相似文献
3.
Caretaker-infant attachment is a complex but well-recognized adaptation in humans. An early instance of (or precursor to)
attachment behavior is the dyadic interaction between adults and infants of 6 to 24 weeks, commonly called "babytalk." Detailed
analysis of 1 minute of spontaneous babytalk with an 8-week infant shows that the poetic texture of the mother’s speech—specifically
its use of metrics, phonetics, and foregrounding—helps to shape and direct the baby’s attention, as it also coordinates the
partners’ emotional communication. We hypothesize that the ability to respond to poetic features of language is present as
early as the first few weeks of life and that this ability attunes cognitive and affective capacities in ways that provide
a foundation for the skills at work in later aesthetic production and response. By linking developmental social processes
with formal cognitive aspects of art, we challenge predominant views in evolutionary psychology that literary art is a superfluous
byproduct of adaptive evolutionary mechanisms or primarily an ornament created by sexual selection.
David S. Miall is Professor of English at the University of Alberta in Canada. He is the author of essays on British Romantic
writers, empirical studies of readers’ responses to literature, hypertext and literary computing. Ellen Dissanayake is Visiting
Scholar at the Walter Chapin Simpson Center for the Humanities, University of Washington. Her most recent book is Art and Intimacy: How the Arts Began (2000). 相似文献
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In this study, several ways have been examined to measure latexpressure, including some novel methods, with the aim of findingbetter methods than are presently available. A novel method,similar to the pressure probe as used for single cells, hasbeen applied to laticifers, exerting a back-pressure to preventexudation. The type of capillary bubble manometer developedby Bourdeau and Schopmeyer for resin pressures (1958) and thenused for latex pressures by Buttery and Boatman (1964, 1966)has been improved and the construction and standardization ofbubble manometer gauges for routine field use has been greatlysimplified. It is concluded that the back-pressure method in its presentstate of development provides neither sufficient rapidity norprecision on account of the slow response time. This methoddoes not justify the two operators needed. The requirement forrelatively large quantities of escaping latex limits its applicationsand, in certain instances, pressurization might be incomplete.Nevertheless, it has provided some additional confidence inthe accuracy of the other methods because readings can oftenbe repeated many times on a single puncture, which is impossiblewith a bubble manometer. Also the gauge used is linear and thereforemore accurate at high pressures than a bubble manometer. The newly designed Buttery and Boatman gauge requires fewerparts and utilizes standard plastic pip-petor tips. These greatlyspeed and simplify construction of the gauges, which are neededin large numbers as they are essentially disposable. These gaugeshave proved to be remarkably reliable, even with minimal latexvolumes, and have always indicated the highest latex pressuresof all methods used at a particular site, suggesting that leakagerates are minimal at the junction between gauge and laticifers.The plastic tip holders facilitate the manual insertion of thesedelicate gauges into the tree bark. Xylem sap is contaminated by phloem sap if collected from petiolesusing a pressure bomb. However, this problem can be overcomein stems by bark ringing. Alternatively, the vacuum extractionmethod can be used which does not seem to suffer from this contaminationproblem. Several ways have been tested to maximize the reliability oflatex serum samples for analysis in a vapour osmometer. Pressureand solute components of water potential can be integrated togive total water potentials. Centrifugation provides the bestmethod to remove rubber particles in Hevea latex: valid osmoticpotentials of serum can be made providing appropriate precautionsare observed. Key words: Latex pressure potentials, laticifer solute potentials, pressure pump, manometer, xylem solute potentials 相似文献
6.
Yang Shu Zachary S. Breitbach Milan K. Dissanayake Sirantha Perera Joseph M. Aslan Nagham Alatrash Frederick M. MacDonnell Daniel W. Armstrong 《Chirality》2015,27(1):64-70
The enantiomeric separation of 21 ruthenium (II) polypyridyl complexes was achieved with a novel class of cyclofructan‐based chiral stationary phases (CSPs) in the polar organic mode. Aromatic derivatives on the chiral selectors proved to be essential for enantioselectivity. The R‐napthylethyl carbamate functionalized cyclofructan 6 (LARIHC CF6‐RN) column proved to be the most effective overall, while the dimethylphenyl carbamate cyclofructan 7 (LARIHC CF7‐DMP) showed complementary selectivity. A combination of acid and base additives was necessary for optimal separations. The retention factor vs. acetonitrile/methanol ratio plot showed a U‐shaped retention curve, indicating that different interactions take place at different polar organic solvent compositions. The separation results indicated that π–π interactions, steric effects, and hydrogen bonding contribute to the enantiomeric separation of ruthenium (II) polypyridyl complexes with cyclofructan chiral stationary phases in the polar organic mode. Chirality 27:64–70, 2015. © 2014 Wiley Periodicals, Inc. 相似文献
7.
Dissanayake VH Bandarage P Pedurupillay CR Jayasekara RW 《Indian journal of human genetics》2010,16(3):164-165
Pentasomy 49,XXXXY is a rare sex chromosome disorder usually presenting with ambigous genitalia, facial dysmorphism, mental retardation and a combination of cardiac, skeletal and other malformations. The incidence of the condition is estimated to be 1 in 85,000 male births. Previously, this condition was identified as a Klinefelter variant. The condition is suspected in a patient, by a combination of characteristic clinical findings, and the diagnosis is confirmed by chromosome culture and karyotyping. In the case we report here, the main presentation of ambiguous genitalia led to a suspicion of a sex chromosome aneuploidy which was subsequently confirmed by chromosomal analysis. 相似文献
8.
The ornamental aquatic plant industry in Sri Lanka has grown substantially during the last decade and there is a renewed demand
for several exotic species. Mayaca fluviatilis, a submerged plant used in aquaria, is not recorded as a naturally occurring plant in Sri Lanka. However, recent studies
recorded it in the wet zone of Sri Lanka and certain countries have recognized it as a problematic plant. The knowledge of
the mode of propagation of invasive species is vital in the management of biological invasions. Therefore, the present study
was conducted to investigate the propagation ability of vegetative parts of M. fluviatilis. A field survey was conducted in the wet zone of Sri Lanka, and populations of M. fluviatilis were monitored between 2006 and 2009. The propagation ability of different maturity stages of stem cuttings (terminal, middle
and basal) were investigated, and terminal stem cuttings with five different lengths (2, 4, 6, 8 and 10 cm) were used to investigate
the propagation ability of fragmented vegetative parts. Terminal shoots showed the highest survival rates and significantly
high (P < 0.05) shoot and root lengths compared to middle and basal parts of the stem cuttings. In the other experiment with terminal
stem cuttings with different lengths, all the stem fragments were capable of developing into a new plant. Increasing lengths
of fragments was significantly related to the number of roots. Nevertheless, as even the 2-cm fragment was capable of developing
into a new plant, removal of even the smallest fragments is necessary to control this plant. Submerged plants can spread easily
through fragmentation and manual removal will likely increase its spread. Nevertheless, it is considered as effective for
small infestations. Therefore, repeated removal of plant parts can be suggested as an ecologically sound management approach
to prevent further spread of M. fluviatilis since it is in the early stage of establishment. 相似文献
9.
There are many proposed and ongoing commercial, industrial, and residential developments within the Darwin Harbour catchment in Northern Australia, to accommodate the projected population growth over the next 20 years. Hence, it is necessary to ensure the balance between these developments and ecosystem conservation. We evaluated ecological risk for the Darwin Harbour using a relative risk model (RRM). The catchment was divided into 22 risk regions based on small catchment boundaries and their homogeneity. Through the RRM, we ranked and summed the stressors and habitats within regions. The interaction between stressors and habitats were modeled through exposure and effect filters. The ecological assessment endpoints were maintenance of the mangrove health and the maintenance of water quality. The risk regions—Myrmidon Creek, Blackmore River, Bleesers Creek, and Elizabeth River—showed the highest total relative risk for ecological assets. These risk regions had a high percentage cover of industrial, commercial, and residential areas; diffuse entry points; and climate change effects. Creek A, Sandy Creek, West Arm, and Pioneer Creek were the risk regions with lowest total relative risk scores. The RRM is a robust application that is suitable for a large geographic area where multiple stressors are of concern. 相似文献
10.
D. M. R. E. A. Dissanayake P. K. D. Chathuranga P. I. Perera M. Vithanage M. C. M. Iqbal 《Bioremediation Journal》2016,20(3):194-208
Removal of Pb(II) from an aqueous environment using biosorbents is a cost-effective and environmentally benign method. The biosorption process, however, is little understood for biosorbents prepared from plant materials. In this study, the biosorption process was investigated by evaluating four adsorption models. A fixed-bed column was prepared using a biosorbent prepared from the aquatic plant Hydrilla verticillata. The effect of bed height and flow rate on the biosorption process was investigated. The objective of the study was to determine the ability of H. verticillata to biosorb Pb(II) from an aqueous environment and to understand the process, through modeling, to provide a basis to develop a practical biosorbent column. Experimental breakthrough curves for biosorption of 50 mg L?1 aqueous Pb(II) using a fixed-bed column with 1.00 cm inner diameter were fitted to the Thomas, Adams-Bohart, Belter, and bed depth service time (BDST) models to investigate the behavior of each model according to the adsorption system and thus understand the adsorption mechanism. Model parameters were evaluated using linear and nonlinear regression methods. The biosorbent removed 65% (82.39 mg g?1 of biosorbent) of Pb(II) from an aqueous solution of Pb(NO3)2 at a flow rate of 5.0 ml min?1 in a 10 cm column. Na2CO3 was used to recover the adsorbed Pb(II) ions as PbCO3 from the biosorbent. The Pb(II) was completely desorbed at a bed height of 10.0 cm and a flow rate of 5.0 ml min?1. Fourier transform infrared (FT-IR) analysis of the native biosorbent and Pb(II)-loaded biosorbent indicated that the hydroxyl groups and carboxylic acid groups were involved in the metal bonding process. The FT-IR spectrum of Pb(II)-desorbed biosorbent showed an intermediate peak shift, indicating that Pb(II) ions were replaced by Na+ ions through an ion-exchange process. Of the four models tested, the Thomas and BDST models showed good agreement with experimental data. The calculated bed sorption capacity N0 and rate constant ka were 31.7 g L?1 and 13.6 × 10?4 L mg?1 min?1 for the Ct/C0 value of 0.02. The BDST model can be used to estimate the column parameters to design a large-scale column. 相似文献