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171.
Healy Matthew D.; Smith Jason E.; Singer Michael S.; Nadkarni Prakash M.; Skoufos Emmanouil; Miller Perry L.; Shepherd Gordon M. 《Chemical senses》1997,22(3):321-326
An olfactory receptor database (ORDB) is being developed tofacilitate analysis of this large gene family. ORDB currentlycontains over 400 olfactory receptor sequences and related information,and is available via the World Wide Web. We plan to incorporatefunctional data, structural models, spatial localization andother categories of information, toward an integrated modelof olfactory receptor function. Chem. Senses 22: 321326,1997. 相似文献
172.
173.
P R Shepherd G W Gould C A Colville S C McCoid E M Gibbs B B Kahn 《Biochemical and biophysical research communications》1992,188(1):149-154
To investigate the tissue distribution of the GLUT3 glucose transporter isoform in human tissue we produced affinity purified antibodies to the COOH terminus of the human GLUT3. Both antibodies recognize a specific GLUT3 band in oocytes injected with GLUT3 mRNA but not in those injected with H2O or GLUT1, 2, 4, 5 mRNA. This immunoreactive band in GLUT3 injected oocytes is photolabelled by cytochalasin-B in the presence of L- but not D-glucose indicating that it is a glucose transporter. A high cross reactivity between the human GLUT3 antibodies and a 43 kDa cytoskeletal actin band was identified in all oocyte lysates and many human tissues. However, the specific GLUT3 band could be distinguished from the actin band by carbonate treatment which preferentially solubilized the actin band. Using these antibodies we show that GLUT3 is present as a 45-48 kDa protein in human brain with lower levels detectable in heart, placenta, liver and a barely detectable level in kidney. No GLUT3 was detected in membranes from any of 3 skeletal muscle groups investigated. We conclude that a major role of GLUT3 in humans is as the brain neuronal glucose transporter. 相似文献
174.
175.
Chitosan functional properties 总被引:7,自引:0,他引:7
Chitosan is a partially deacetylated polymer of N-acetyl glucosamine. It is essentially a natural, water-soluble, derivative
of cellulose with unique properties. Chitosan is usually prepared from chitin (2 acetamido-2-deoxy β-1,4-D-glucan) and chitin
has been found in a wide range of natural sources (crustaceans, fungi, insects, annelids, molluscs, coelenterata etc.) However
chitosan is only manufactured from crustaceans (crab and crayfish) primarily because a large amount of the crustacean exoskeleton
is available as a by product of food processing. Squid pens (a waste byproduct of New Zealand squid processing) are a novel,
renewable source of chitin and chitosan. Squid pens are currently regarded as waste and so the raw material is relatively
cheap. This study was intended to assess the functional properties of squid pen chitosan. Chitosan was extracted from squid
pens and assessed for composition, rheology, flocculation, film formation and antimicrobial properties. Crustacean chitosans
were also assessed for comparison. Squid chitosan was colourless, had a low ash content and had significantly improved thickening
and suspending properties. The flocculation capacity of squid chitosan was low in comparison with the crustacean sourced chitosans.
However it should be possible to increase the flocculation capacity of squid pen chitosan by decreasing the degree of acetylation.
Films made with squid chitosan were more elastic than crustacean chitosan with improved functional properties. This high quality
chitosan could prove particularly suitable for medical/analytical applications.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
176.
The immunophenotype of HT29 human colon cancer cells implanted into severe combined immunodeficient mice was assessed in primary
tumours and their metastases in the lungs using an indirect immunohistochemical method. After primary tumours were surgically
removed, the metastases were given time to develop, thus paralleling the clinical situation. While vimentin was negative in
both primary and secondary tumours, E-cadherin was present as membrane-bound labelling in the primary tumours only. Whereas
the markers p53, MIB1, PCNA and CEA were consistently positive in both primary and metastatic tumours, CD44 variant 6 and
CA125 were negative in metastases but positive in the primary tumours. There was a significant increase in the percentage
of cells labelled for p53 in the primary tumours compared with the metastases. For the proliferation markers, there was no
significant difference in labelling between primary tumours and metastases for MIB1. Of the cytokeratins examined, CK 20 gave
the strongest and most consistent reaction in both primary and secondary tumours. The results indicate that, for certain immunohistochemical
markers, results are the same in both primary tumours and metastases. Hence, in these cases, antigens that are expressed on
the primary tumour as well as on the metastases can serve as target molecules for immunologically based forms of treatment
of metastases.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
177.
Three known and two new diterpenes were isolated from the ethyl acetate extract of Hymenaea courbaril var. stilbocarpa seed pods. One of the compounds was elucidated as (5R*,8S*,9S*,10R*)-cleroda-3,13E-dien-15-oic acid and the other was elucidated, after treatment with diazomethane, as methyl (5S*,8S*,9S*,10R*)-cleroda-3,13E-dien-15-oate. The known diterpenes were identified as (-)-ozic acid, (-)-isoozic acid and (-)-kovalenic acid which were characterized as their methyl ester derivatives. 相似文献
178.
N M Tyrer D Shepherd D W Williams 《The journal of histochemistry and cytochemistry》2000,48(11):1575-1582
We describe staining protocols for serial semithin sections of Drosophila central ganglia that allow visualization of gene expression in particular neurons with counterstaining to display the ganglion architecture. Green fluorescent protein (GFP), expressed in a subset of sensory neurons from a selected enhancer trap line, is visualized by conventional immunohistochemistry with a peroxidase-linked antibody, and neural architecture is revealed by reduced silver staining. This makes visible in histological sections the same GFP-labeled cells seen with confocal microscopy, but with the especial advantage that neuropil structures are also revealed at the level of individual cells and neuron processes. Not only does this allow the physical relationships among intracellularly labeled neurons to be determined by reference to specific features in the neuropil but it also enables a function to be ascribed provisionally to particular regions of neuropil. These methods have particular utility for mapping morphological information on specific neurons in the context of central nervous system architecture, both in adult Drosophila and during development. 相似文献
179.
Tonoplast, ion antiport activities are critical to ion homeostasis and sequestration in plants. The biochemical properties of these activities, and the enzymes that catalyse them, are little characterized. Here we applied biochemical approaches to study some characteristics and to distinguish between Ca2+/H+ and Cd2+/H+ antiporter activities of tonoplast vesicles from non‐transformed, wild‐type plants. Solubilization and reconstitution of oat‐seedling (Avena sativa L.) root tonoplast vesicles resulted in about a 6‐fold loss of protein, about a 6‐fold enhancement of Cd2+/H+ antiport specific activity (at 10 µM Cd2+), and almost complete loss of Ca2+/H+ antiport activity. Similar results were found for vesicles from mature tobacco (Nicotiana tabacum) roots. Cd2+ concentration‐dependent proton efflux was similar and linear with both oat vesicles and proteoliposomes. In contrast, Ca2+ concentration‐dependent proton efflux of oat vesicles was easily observed while that with proteoliposomes was minimal and non‐linear. Cd2+ pre‐treatment of oat vesicles reduced verapamil inhibition of Cd2+/H+ activity and verapamil binding to vesicles, while Ca2+ pre‐treatment was much less protective of Ca2+/H+ activity and verapamil binding. Results show the usefulness of reconstitution, and also inhibitor/ion interaction assays for distinguishing between transporter activities in vitro, but they do not resolve the question of whether there are separate enzymes for Cd2+/H+ and Ca2+/H+. Our observation that solubilization and reconstitution have similar effects on both Cd2+/H+ and Ca2+/H+ activities of root tonoplast vesicles from immature oat and mature tobacco roots suggests that the transporters involved are similar in young and mature roots, and in roots of different species. 相似文献
180.