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排序方式: 共有269条查询结果,搜索用时 17 毫秒
1.
G Sansone M Cotugno A Biondi 《Bollettino della Società italiana di biologia sperimentale》1983,59(4):509-513
The Authors have investigated the structural property of organic shell matrix from Mytilus galloprovincialis by scanning microscopy. The microscopic investigation shows differences between matrix from nacreous layer or argonite and matrix from outer layer or calcite. The first shows a "cavernous" surface; the other instead shows a "smooth" surface. The Authors conclude that probably these differences may influence the different crystallographic arrangement of biocrystals. 相似文献
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The kinetics of t-[3H]butylbicycloorthobenzoate (TBOB) binding to the convulsant sites of the γ-aminobutyric acidA (GABAA) receptor-ionophore complex were examined in synaptosomal membrane preparations of rat brain. On and off rates of TBOB binding were accelerated by 1 μM GABA and decelerated by 1 μM bicuculline methochloride, a GABAA antagonist. The presence of GABA and bicuculline methochloride created rapid and slow phases of dissociation, respectively. The three groups of rate constants distinguished for the dissociation of 4 nM and 30 nM [3H]TBOB represent multiaffinity states of the convulsant sites depending on the presence of GABA or bicuculline methochloride. Apparent association rate constants do not obey the equation kapp=koff±kon [TBOB] without assuming interconvertibility of the kinetic states during binding. Avermectin B1a (AVM B1a), a chloride channel opening agent, accelerated the association and dissociation of TBOB and resulted in a biphasic effect on TBOB binding, i.e., enhancement at low concentrations (EC50, 7.8 nM) followed by displacement at high concentrations (IC50 6.3 μM) of AVM B1a. AVM B1a resulted in similar biphasic effects on t- [35S]butylbicyclophosphorothionate binding. DIDS, an isothiocyanatostilbene derivative with irreversible anion channel blocking effect, selectively inhibited basal [3H]TBOB binding (IC50 125 μM DIDS) leaving the enhancement by AVM B1a unaffected. 相似文献
5.
E. B. Sansone A. M. Losikoff W. B. Lebherz III J. A. Poiley 《In vitro cellular & developmental biology. Plant》1981,17(9):811-815
Summary To estimate worker exposures to, and environmental contamination from, test chemicals and organic solvents used in an in vitro
assay to assess the carcinogenic potential of chemicals, sodium fluorescein, a noncarcinogenic fluorescent material, was dissolved
in tissue culture medium used to maintain early passage hamster embryo cells. Personal and environmental samples were taken
over a 14-d period. The assay was performed according to standard procedures in a ventilated glove box or laminar flow safety
cabinet. Considerably more than 99% of the chemical contamination found was recovered from the interiors of the glove box
and hood and from disposable equipment. Contamination outside the containment units (less than 1 μg) resulted from intralaboratory
transport of chemicals, treated cultures, and contaminated equipment. We conclude that the standard operating practices and
procedures provided adequate safeguards for personnel and the environment.
Research sponsored by the National Cancer Institute under Contract N01-CO-75380, with Litton Bionetics, Inc. 相似文献
6.
Aqueous solutions of a number of biological stains were completely decontaminated to the limit of detection using Amberlite resins. Amberlite XAD-16 was the most generally applicable resin but Amberlite XAD-2, Amberlite XAD-4, and Amberlite XAD-7 could be used to decontaminate some solutions. Solutions of acridine orange, alcian blue 8GX, alizarin red S, azure A, azure B, Congo red, cresyl violet acetate, crystal violet, eosin B, erythrosin B, ethidium bromide, Janus green B, methylene blue, neutral red, nigrosin, orcein, propidium iodide, rose Bengal, safranine O, toluidine blue O, and trypan blue could be completely decontaminated to the limit of detection and solutions of eosin Y and Giemsa stain were decontaminated to very low levels (less than 0.02 ppm) using Amberlite XAD-16. Reaction times varied from 10 min to 18 hr. Up to 500 ml of a 100 micrograms/ml solution could be decontaminated per gram of Amberlite XAD-16. Fourteen of the 23 stains tested were found to be mutagenic to Salmonella typhimurium. None of the completely decontaminated solutions were found to be mutagenic. 相似文献
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Javier Hernán Rojo Daniel Alfredo Fernández Daniel Enrique Figueroa Claudia Clementina Boy 《Journal of fish biology》2020,96(4):956-967
This study reports the phenotypic and genetic differences between individuals of puyen Galaxias maculatus from two sites in the same river basin in Tierra del Fuego National Park, southern South America. Individuals from the two sampling sites presented morphometric and genetic differences. The morphometric differences indicated that individuals from Laguna Negra (LN) were short and more robust and had large eyes, whereas those from Arroyo Negro (AN) were thin and elongated and had small eyes. Genetic differences showed that AN individuals had a greater genetic structuration and an older demographic history than LN individuals. The results of this study affirmed that the individuals from the two sampling sites belong to different populations with a high degree of isolation. The demographic history could indicate that the individuals of G. maculatus which migrated to northern areas during the last glaciation settled in the Beagle Channel after its formation. The LN population could have originated after the retreat of the glaciers, migrating from AN. 相似文献
9.
Juan Francisco Ornelas Clementina González Blanca E. Hernández‐Ba?os Jaime García‐Moreno 《Ecology and evolution》2016,6(4):1104-1127
The present day distribution and spatial genetic diversity of Mesoamerican biota reflects a long history of responses to habitat change. The hummingbird Lampornis amethystinus is distributed in northern Mesoamerica, with geographically disjunct populations. Based on sampling across the species range using mitochondrial DNA (mtDNA) sequences and nuclear microsatellites jointly analysed with phenotypic and climatic data, we (1) test whether the fragmented distribution is correlated with main evolutionary lineages, (2) assess body size and plumage color differentiation of populations in geographic isolation, and (3) evaluate a set of divergence scenarios and demographic patterns of the hummingbird populations. Analysis of genetic variation revealed four main groups: blue‐throated populations (Sierra Madre del Sur); two groups of amethyst‐throated populations (Trans‐Mexican Volcanic Belt and Sierra Madre Oriental); and populations east of the Isthmus of Tehuantepec (IT) with males showing an amethyst throat. The most basal split is estimated to have originated in the Pleistocene, 2.39–0.57 million years ago (MYA), and corresponded to groups of populations separated by the IT. However, the estimated recent divergence time between blue‐ and amethyst‐throated populations does not correspond to the 2‐MY needed to be in isolation for substantial plumage divergence, likely because structurally iridescent colors are more malleable than others. Results of species distribution modeling and Approximate Bayesian Computation analysis fit a model of lineage divergence west of the Isthmus after the Last Glacial Maximum (LGM), and that the species’ suitable habitat was disjunct during past and current conditions. These results challenge the generality of the contraction/expansion glacial model to cloud forest‐interior species and urges management of cloud forest, a highly vulnerable ecosystem to climate change and currently facing destruction, to prevent further loss of genetic diversity or extinction. 相似文献
10.
Susanna-Assunta Sansone Daniel Schober Helen J. Atherton Oliver Fiehn Helen Jenkins Philippe Rocca-Serra Denis V. Rubtsov Irena Spasic Larisa Soldatova Chris Taylor Andy Tseng Mark R. Viant 《Metabolomics : Official journal of the Metabolomic Society》2007,3(3):249-256
In this article we present the activities of the Ontology Working Group (OWG) under the Metabolomics Standards Initiative
(MSI) umbrella. Our endeavour aims to synergise the work of several communities, where independent activities are underway
to develop terminologies and databases for metabolomics investigations. We have joined forces to rise to the challenges associated
with interpreting and integrating experimental process and data across disparate sources (software and databases, private
and public). Our focus is to support the activities of the other MSI working groups by developing a common semantic framework
to enable metabolomics-user communities to consistently annotate the experimental process and to enable meaningful exchange
of datasets. Our work is accessible via a public webpage and a draft ontology has been posted under the Open Biological Ontology
umbrella. At the very outset, we have agreed to minimize duplications across omics domains through extensive liaisons with
other communities under the OBO Foundry. This is work in progress and we welcome new participants willing to volunteer their
time and expertise to this open effort.
See the MSI Ontology Working Group website for a complete list of members and contributors. Web URL: 相似文献