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871.
The effects of temperature (25–45 °C) and pH (7.5–5.5) on photosystem (PS) 2 was studied in spinach (Spinacia oleracea L.) thylakoid membranes using chlorophyll a fluorescence induction kinetics. In high temperature and low pH treated thylakoid membranes a decline in the variable to
maximum fluorescence ratio (Fv/Fm) and PS 2 electron transport rate were observed. More stacking in thylakoid membranes, studied by digitonin fractionation
method, was observed at low pH, while the degree of unstacking increased under high temperature conditions. We conclude that
the change in pH does not significantly affect the donor/acceptor side of PS 2 while high temperature does. Fluorescence emission
spectra at 77 K indicated that low pH is associated with energy redistribution between the two photosystems while high temperature
induced changes do not involve energy re-distribution. We suggest that both, high temperature and low pH, show an inhibitory
effect on PS 2 but their mechanisms of action are different. 相似文献
872.
873.
874.
Summary Active male gerbils were rendered unilaterally cryptorchid and the enzymatic changes were studied after 48, 60 and 100 days. The histochemical observations revealed inhibition of alkaline phosphatase, acid phosphatase, 5-nucleotidase, adenosine-tri-phosphatase and succinic dehydrogenase activities in the germinal elements of the seminiferous tubules. The non-specific esterase and succinic dehydrogenase activities increased in the Leydig cells to certain extent. The sudanophilic lipids increased in the Sertoli cells and the interstitial cells. An attempt has been made to approach the intricate problem of the spermatogenesis in order to understand the sequence of certain enzymatic activities in the gerbil testis in which spermatogenesis is suppressed when one of the testes is lodged inside the abdominal cavity. 相似文献
875.
Degradation of soil humus by the fairy ring mushroom 总被引:3,自引:0,他引:3
S. P. Mathur 《Plant and Soil》1970,33(1-3):717-720
Summary Except when cultures were well aerated by shaking,Marasmius oreades (Bolt.) Fr., the fairy ring mushroom, was able to utilize, in pure culture studies, fractions of humus from sources as divergent
as the A horizon of a chernozemic soil and the Bh horizon of a Podzol. The importance of this ability to soil infestation
was discussed and it was suggested that improved soil aeration be studied as a control measure.
Contribution No.316. 相似文献
876.
877.
878.
W D Leighton R C Russell A M Feller E Eriksson A Mathur E G Zook 《Plastic and reconstructive surgery》1988,82(1):76-87
There is a statistically significant increase in blood flow into expanded cutaneous and myocutaneous flaps in a pig model over controls. The vascular trees within flaps enlarge following expansion, and pronounced neovascularization is seen in the papillary dermis and capsular layers. Experimentally, there is differential thinning of all tissue layers except the epidermis. A successful clinical application of this technique, by free-tissue transfer of an expanded fasciocutaneous scapular flap, is described. The technique is applicable when altered flap size or contour is desired. 相似文献
879.
The chromosomal complements of five species of mammals, Mus musculus (Linn.), Rattus rattus rattus (Linn.), Bandicota bengalensis (Gray and Hardw.), Funambulus pennanti (Wr.) and Lepus ruficaudatus (Geoff.) were elaborated. The karyotypes of all the species were compared. The diploid number (2n) in Mus is 40, Rattus 42, Bandicota 42, Funambulus 54 and Lepus 48. An extra large X-chromosome was observed in one population of male Rattus rattus rattus (Linn.), which might have been formed as a result of duplication of the terminal segments of both the arms of the chromosomes. 相似文献
880.