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531.
Baldev B. Singh George S. Schuster Virginia A. Merchant Virginia J. Michelich 《In vitro cellular & developmental biology. Plant》1979,15(11):865-872
Summary Epithelial outgrowths from hamster cheek pouch explants were cultured for varying peroids of time up to 22 days. Growth of
the epithelial sheets was monitored, employing colcemid for demonstrating mitotic activity and tritiated thymidine for DNA
synthesis. Mitoses and thymidine uptake were observed among epithelial outgrowths at a considerable distance from the original
explant. The epithelial nature of the growing cell sheets was confirmed, employing electron microscopic techniques. The cells
exhibited the presence of tonofilaments, desmosomes, ribosomes, Golgi, mitochondria, and rough endoplasmic reticulum. The
cultured explants were treated with cyclic nucleotides in order to investigate their modulatory effects on epithelial cell
differentiation. Dibutyryl cAMP induced marked mitotic inhibition (46.3%) in our assay, which was increased to 57% with the
addition of theophylline. Dibutyryl cGMP showed only a mild (5%) stimulatory effect on mitotic activity. Dibutyryl cAMP enhanced
keratinization in the epithelial cell out-growths with the biogenesis of keratohyalin granules, whereas dibutyryl cGMP did
not produce any observable alterations. 相似文献
532.
Priscila Ferreira Batista Caroline Müller Andrew Merchant David Fuentes Robson de Oliveira Silva-Filho Fábia Barbosa da Silva Alan Carlos Costa 《Physiologia plantarum》2020,168(2):456-472
Soybean is the most widely grown oilseed in the world. It is an important source of protein and oil which are derived from its seeds. Drought stress is a major constraint to soybean yields. Finding alternative methods to mitigate the water stress for soybean is useful to maintain adequate crop yields. The aim of this study was to evaluate the morpho-physiological, biochemical and metabolic changes in soybean plants in two ontogenetic stages, under exposure to water deficit and treatment with zinc sulphate (ZS), potassium phosphite (PP) or hydrogen sulphide (HS). We carried out two independent experiments in the V4 and R1 development stages consisting of the following treatments: well-watered control (WW, 100% maximum water holding capacity, MWHC), water deficit (WD, 50% MWHC), PP + WW, PP + WD, HS + WW, HS + WD, ZS + WW and ZS + WD. The experimental design consisted of randomized blocks with eight treatments with five replicates. Morphological, physiological and metabolic analyses were performed 8 days after the start of the treatments for both experiments. We identified two tolerance mechanisms acting in response to compound application during water stress: the first involved the upregulation of antioxidant enzyme activity and the second involved the accumulation of soluble sugars, free amino acids and proline to facilitate osmotic adjustment. Both mechanisms are related to the maintenance of the photosynthetic parameters and cell membrane integrity. This report suggests the potential agricultural use of these compounds to mitigate drought effects in soybean plants. 相似文献
533.
534.
R J Linhardt Z M Merchant D W Persinger 《The International journal of biochemistry》1985,17(11):1179-1183
Polyclonal IgG rabbit antibodies were prepared against a purified heparinase from Flavobacterium heparinum. Immuno-affinity purification of crude and partially purified heparinase is described. The resulting enzyme was of comparable purity to that prepared using the standard multistep purification scheme. The antibodies prepared were found to increase the activity of bound heparinase. 相似文献
535.
536.
Human clinical and psychophysical observations suggest that the taste
system is able to compensate for losses in peripheral nerve input, since
patients do not commonly report decrements in whole mouth taste following
chorda tympani nerve damage or anesthesia. Indeed, neurophysiological data
from the rat nucleus of the solitary tract (NST) suggests that a release of
inhibition (disinhibition) may occur centrally following chorda tympani
nerve anesthesia. Our purpose was to study this possibility further. We
recorded from 59 multi- and single- unit taste-responsive sites in the rat
NST before, during and after recovery from chorda tympani nerve anesthesia.
During anesthesia, average anterior tongue responses were eliminated but no
compensatory increases in palatal or posterior tongue responses were
observed. However, six individual sites displayed increased taste
responsiveness during anesthesia. The average increase was 32.9%.
Therefore, disinhibition of taste responses was observed, but infrequently
and to a small degree in the NST At a subset of sites, chorda
tympani-mediated responses decreased while greater superficial
petrosal-mediated responses remained the same during anesthesia. Since this
effect was accompanied by a decrease in spontaneous activity, we propose
that taste compensation may result in part by a change in signal-to-noise
ratio at a subset of sites.
相似文献