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31.
A novel metalloproteinase gene specifically expressed in stromal cells of breast carcinomas. 总被引:46,自引:0,他引:46
P Basset J P Bellocq C Wolf I Stoll P Hutin J M Limacher O L Podhajcer M P Chenard M C Rio P Chambon 《Nature》1990,348(6303):699-704
A gene has been identified that is expressed specifically in stromal cells surrounding invasive breast carcinomas. On the basis of its sequence, the product of this gene, named stromelysin-3, is a new member of the family of metalloproteinase enzymes which degrade the extracellular matrix. The suggestion is that stromelysin-3 is one of the stroma-derived factors that have long been postulated to play an important part in progression of epithelial malignancies. 相似文献
32.
Mark C. Hove Bernard E. Sietman Matthew S. Berg Erika C. Frost Kiru Wolf Tony R. Brady 《Journal of Natural History》2016,50(9-10):523-542
Managing a rare species can be improved with knowledge of its natural history. The sheepnose (Plethobasus cyphyus) is a freshwater mussel recently listed by the US as federally endangered. We used standard methods to study P. cyphyus brooding behaviour, host fishes in the laboratory and under natural conditions, and glochidial morphology. We monitored a population of P. cyphyus in the Chippewa River, WI during spring and summer 2007–2009 and 2011 and found brooding animals between mid-May and early August. Gravid individuals ranged between 5 and 27 yr (mean age ± 1 s.d. = 13 ± 4 yr). Plethobasus cyphyus brooded glochidia in outer gills, which varied in colour from red, orange, pink, cream, or white. We observed mature glochidia more commonly in individuals with cream or white gills and these glochidia were released in a clear, adhesive, mucus matrix. In laboratory trials we found several minnow and topminnow species (29 spp.) served as productive suitable native hosts. The mean number of juvenile mussels released per cyprinid per day was significantly higher for trials conducted at 22–25°C compared with those at 18–20°C, and 83% of trials conducted at 18–20°C using suitable host species produced no juveniles. Glochidia had a unique outline and shell morphometrics that distinguished P. cyphyus from seven other Chippewa River mussel species that produce similar sized glochidia. Using morphometrics we determined that mimic shiners (Notropis volucellus) were natural hosts for P. cyphyus, round pigtoe (Pleurobema sintoxia), and Wabash pigtoe (Fusconaia flava). Releasing mucus-bound glochidia has evolved in a variety of mussel species and may be more common than is currently realized. Our data show that P. cyphyus is a cyprinid host specialist, and propagation efforts for this species can be strengthened through improved access to mature glochidia by using females with cream-coloured gills and increased juvenile production through warmer fish holding temperatures. 相似文献
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The direct effect of serotonin and antiserotonin agents on adrenal steroid biosynthesis was studied in isolated adrenal cells derived from patients with Cushing's syndrome. The results indicate that serotonin increases corticosterone production, while the serotonin antagonists cyproheptadine and methysergide depress adrenal steroid - particularly cortisol and aldosterone - biosynthesis. 相似文献
35.
Stimulation of the nucleus accumbens evokes a potent inhibition in neurons of the ventral tegmental area. GABA is likely to act as a transmitter in this descending inhibitory system. 相似文献
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Phorbol esters are potent tumour-promoting agents that exert pleiotropic effects on cells. Among these are the control of growth, stimulation of release of stored bioactive constituents and regulation of growth-factor surface receptors. Phorbol esters bind to and activate protein kinase C, leading to the phosphorylation of specific protein substrates presumed to be necessary for eliciting the full response. Strong evidence exists that specific binding of tumour promoter occurs at the membrane level in intact cells, resulting in activation of protein kinase C. Recent evidence concerning the release of bioactive constituents from platelets and neutrophils has linked agonist-induced protein kinase C activation and Ca2+ mobilization in a synergistic mechanism. Here we present a novel model of synergism between Ca2+ and phorbol esters that leads to transferrin receptor phosphorylation and down-regulation in HL-60 human leukaemic cells. Raising intracellular Ca2+, although ineffective by itself, increases the potency and rate of action of phorbol ester for activating protein kinase C and mediating transferrin receptor phosphorylation and down-regulation. We propose a molecular model in which increased intracellular Ca2+ recruits protein kinase C to the plasma membrane, thus "priming' the system for activation by phorbol ester. 相似文献
39.
Three-dimensional structure of the E. coli DNA-binding protein FIS 总被引:27,自引:0,他引:27
D Kostrewa J Granzin C Koch H W Choe S Raghunathan W Wolf J Labahn R Kahmann W Saenger 《Nature》1991,349(6305):178-180
40.
Susan Wolf 《Foundations of Science》2016,21(2):279-282
Responding to comments by Cheshire Calhoun and Arnold Burms, this piece clarifies some of Wolf’s ideas about the relation between meaningfulness in life, on the one hand, and reasons of love, fulfillment, and objective value, on the other. Meaning tends to come from activities whose reasons are grounded in love of a worthy (objectively valuable) object, and not necessarily from reasons having anything to do with an interest in meaningfulness itself. But what counts as a worthy object cannot be determined either from a totally neutral and impersonal point of view or from the points of view of specific other people who matter to the subject. 相似文献