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11.
Jacques Defaye Hugues Driguez Bernard Henrissat Edith Bar-Guilloux 《Carbohydrate research》1983,124(2):265-273
(1,1′-13C)α,α-Trehalose was obtained in 37% yield from the Pavia condensation of 2,3,4,6-tetra-O-benzyl-d-(1-13C)glucopyranose, in dichloromethane in the presence of trifluoromethanesulfonic anhydride, followed by the usual deprotection techniques. The hydrolysis of this substrate by cockchafer trehalase was monitored at 37° by using 13C-n.m.r. spectroscopy with short recording times. Equimolecular amounts of α- and β-d-glucopyranose are released simultaneously by the action of the enzyme. This result is consistent with a bimolecular substitution mechanism, taking into account previous results involving C-2 asymmetric participation in the catalytic step of hydrolysis of α,α-trehalose. For comparative evaluation of its accuracy, the usual polarimetric technique was also used for the determination of the anomeric configuration of the d-glucose released by the action of the enzyme on α,α-trehalose. 相似文献
12.
Richard P. Bunge Mary Bartlett Bunge Edith R. Peterson 《The Journal of cell biology》1965,24(2):163-191
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Toshiro Nagayoshi Marie-Genevive Mattei Edith Passage Robert Knowlton Mon-Li Chu Jouni Uitto 《Genomics》1989,5(4):932-935
Laminin, an integral component of basement membranes, consists of three subunit polypeptides, A, B1, and B2 chains. We have recently isolated cDNAs corresponding to human laminin A chain. These cDNAs were utilized for chromosomal in situ hybridizations to establish the genomic location of the laminin A chain gene. Metaphase chromosomes of PHA-stimulated human peripheral blood leukocytes were examined by in situ hybridization with 3H-labeled cDNAs, and the chromosomes were identified by R-banding (fluorochrome-photolysis-Giemsa method). The results indicated that the human laminin A chain is at locus 18p11.3. Since human laminin B1 and B2 chain genes have been previously mapped to chromosomes 7 and 1, respectively, the results indicate that genes encoding human laminin chains reside in separate chromosomes. 相似文献
17.
Spontaneous cholelithiasis was found in seven owl monkeys (Aotus spp.) at necropsy. There were four male and three female animals. Antemortem clinicopathologic findings included weight loss, anemia, increased alanine aminotransferase and gamma glutamyl transpeptidase, and hyperbilirubinemia in several animals. Choleliths ranged in size from sand-like particles to 5 mm in diameter. Gallstones from five animals were analyzed by accepted analytical methods. Results showed the gallstones to be composed primarily of cholesterol (89%). The gallbladder was histologically normal in all cases examined. The etiopathogenesis of cholelithiasis in the owl monkey is unknown. 相似文献
18.
R E Weller R L Buschbom H A Ragan J F Baer C A Malaga 《Journal of medical primatology》1990,19(5):439-446
A positive linear relationship was found between total calcium and albumin and between total calcium and total protein in the serum of 205 owl monkeys. Adjustment formulas for calcium were derived: adjusted calcium (mg/dl) = measured calcium (mg/dl) - 0.84 [albumin (g/dl)] + 3.8 and adjusted calcium (mg/dl) = measured calcium (mg/dl) - 0.82 [total protein (g/dl)] + 6.5. Adjusted calcium calculations for monkeys based on albumin concentration were similar to those for man and dogs, but different from those based on total protein. 相似文献
19.
Thomas N. Taylor Georgina M. Del Fueyo Edith L. Taylor 《American journal of botany》1994,81(6):666-677
In this paper we describe the first anatomically preserved Mesozoic seed fern cupule–Petriellaea. The multiovulate cupules were produced singly at the end of a short dichotomizing axis. Cupules are bilateral with a dorsal groove and transverse narrow ventral opening. The vascular system of the cupule consists of a series of traces that extend up the dorsal surface of the cupule and down the ventral face. Ovules are orthotropus, sessile, and borne on the adaxial surface of the leaflike cupule either singly or in multiple rows. They are up to 1.5 mm long, triangular in transverse section, and characterized by a multilayered integument. Nucellus and integument are fused throughout their length, but no pollen chamber is present. In the chalaza is a small vascular disc of transfusion tracheids that represents the extent of the ovule vascular system. Ovules are interpreted as being fossilized at a prepollination stage, although a few possess some evidence of a cellularized megagametophyte. These permineralized cupules indicate that in at least one Mesozoic seed fern group, ovule enclosure resulted from the transverse folding (tip to petiole) of a megasporophyll bearing adaxial ovules. Cupule morphology and ovule enclosure in other Late Paleozoic and Mesozoic seed ferns is discussed. 相似文献
20.
Ion balance in tomato cultivars differing in salt tolerance. I. Sodium and potassium accumulation and fluxes under moderate salinity 总被引:1,自引:0,他引:1
The magnitude of sodium and potassium fluxes in Lycopersicon escutentum cuhivars Ace and Edkawi (Edkawi is considered more sait-tolerant I was evaluated in planls grown for 10 days in aerated Hoagland solution with the addition of 25 or 100 mM NaCl. Ion accumulatiun in different plant pans, ion concentration in xylem exudate. transpiration and membrane leakiness were measured. Both cultivars responded very similarly to these levels of salinity in terms of growth. No conspicuous differences in membrane leakiness were observed. Net uprake rates were calculated from ion contents data. Potassium uptake rates were lower in salinized planls than in controls, especially in cv. Aee. Potassium/sodium selectivity ratios were much higher in Edkawi than in Ace. and higher in shoot uptake rates than in xy lem exudate. This indicates that Edakw i has a higher capacity to retain potassium under salinity, a character which could contribute to its salt-tolerance. 相似文献