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51.
The effect of waveguiding property (i.e., the intensity distribution) of the photoreceptor on the number of photons absorbed in a photoreceptor has been studied. It has been found that the effect is significant only for large values of the exposure and the maximum effect is less than 11% in the case of human rod photoreceptor. In the analysis, the funnelling effect, which follows from the coupling between the interior and exterior fields, has not been considered.Work partially supported by the Department of Science and Technology (India)B. D. Gupta is associated with the School of Bioscience Studies 相似文献
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The oxidants of the SH groups (o-iodozobenzoate, oxidized glutathione, etc.) and the divalent cations of some metals (Zn2+ and Cd2+) significantly slow down the rate of inactivation by the protein inhibitor of the isolated F1-ATPase and ATPase in submitochondrial particles. Modification of SH groups in the ATPase does not change the rate of inactivation but completely prevents the effect of oxidants. 相似文献
54.
O W Witte E J Speckmann J Walden 《Comp. Biochem. Physiol. C, Comp. Pharmacol. Toxicol.》1985,80(1):37-45
The ionic composition of the currents underlying the acetylcholine (ACh) depolarizations in the identified neurons B1 and B3 of the buccal ganglia of Helix pomatia was analysed. The equilibrium potential of the ACh responses was -2.8 +/- 0.6 mV (N = 49) and -4.0 +/- 0.7 mV (N = 79; mean +/- SEM) in the neurons B1 and B3, respectively. Replacement of NaCl in the bath solution by sucrose shifted the ACh equilibrium potential into the negative direction. A similar but less pronounced shift occurred when Ca2+ was substituted for Na+. Substitution of Cl- in the bath solution by propionate or an increase of the intracellular Cl- concentration did not affect the ACh equilibrium potential. Changes of K+ concentration in the bath between 1 and 50 mmol/l left the ACh equilibrium potential nearly unaffected when the Na+ concentration was at the control level. With a simultaneous reduction of extracellular Na+ an increase of K+ concentration shifted the ACh equilibrium potential towards more positive potentials. The findings are compatible with calculated K+ permeabilities if a K+ redistribution across the cell membrane is considered. In the neurons B1 and B3, channels operated by ACh are permeable for K+, Na+ and Ca2+, with the relative permeabilities 1.6:1.0:0.1. 相似文献
55.
The effects of 5-methoxy-N, N-dimethyltryptamine (5-MeODMT), a serotonin agonist with a preferential action on presynaptic autoreceptors, on prolactin release in male rats was determined. Basal serum prolactin levels were not altered after administration of 1.0, 2.0, 5.0, 10.0 or 20.0 mg/kg of 5-MeODMT.Pretreatment with 5-MeODMT reduced prolactin release by agents that depend on serotonergic neurotransmission for part of their prolactin release stimulation. Prolactin release in response to L-5-hydroxytryptophan (5-HTP) or morphine was significantly reduced by pretreatment of the rats with 5-MeODMT.The results of this experiment indicate that 5-MeODMT act as a presynaptic serotonin autoreceptor stimulant and not as a postsynaptic serotonin agonist on the neuronal systems that control prolactin release. 相似文献
56.
H. G. Kilian M. Kazda F. Király D. Kaufmann R. Kemkemer D. Bartkowiak 《Cell biochemistry and biophysics》2010,57(2-3):87-100
If growing cells in plants are considered to be composed of increments (ICs) an extended version of the law of mass action can be formulated. It evidences that growth of plants runs optimal if the reaction–entropy term (entropy times the absolute temperature) matches the contact energy of ICs. Since these energies are small, thermal molecular movements facilitate via relaxation the removal of structure disturbances. Stem diameter distributions exhibit extra fluctuations likely to be caused by permanent constraints. Since the signal–response system enables in principle perfect optimization only within finite-sized cell ensembles, plants comprising relatively large cell numbers form a network of size-limited subsystems. The maximal number of these constituents depends both on genetic and environmental factors. Accounting for logistical structure–dynamics interrelations, equations can be formulated to describe the bimodal growth curves of very different plants. The reproduction of the S-bended growth curves verifies that the relaxation modes with a broad structure-controlled distribution freeze successively until finally growth is fully blocked thus bringing about “continuous solidification”. 相似文献
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Widespread occurrence of AP in amyloidotic tissues. An immunohistochemical observation 总被引:1,自引:0,他引:1
T Shirahama M Skinner J D Sipe A S Cohen 《Virchows Archiv. B, Cell pathology including molecular pathology》1985,48(3):197-206
Plasma (P)-component of amyloid (AP or SAP), while not an integral part of the amyloid fibril, has been considered to be intimately associated with virtually every different type of amyloid. In the present study, we evaluated the distribution of AP in the organs frequently involved in two forms of human systemic amyloidosis (AA and AF) and in mouse AA amyloidosis, by use of immunohistochemistry with anti-AP. Although the amyloid deposits generally showed moderate reactions with anti-AP, they were not always clearly distinguished from the surrounding non-amyloid tissue elements which often stained as well. The basement membrane often showed even stronger reaction to anti-AP than the adjacent amyloid deposits, and liver sections demonstrated such a high overall reaction to anti-AP that the anti-AP reaction on the amyloid deposits was often obscurred. The present results suggest that the binding between AP and the amyloid fibril may not be monospecific, that AP by this technique occurs rather widely throughout the body, and therefore that anti-AP may not be considered as specific a marker for amyloid deposits in immunohistochemical and perhaps other studies as well. 相似文献
59.
S V Prozorovski? L P Tsarevski? G A Levina A L Gorelov 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1985,(8):10-14
To simulate the infectious process and to study the persistence of L-forms, rabbits and guinea pigs were infected with S. typhi stable L-forms. The materials presented in this work indicate that both subconjunctival and intraperitoneal infection led to the development of the clinically indistinct, but morphologically pronounced pathological process with characteristic localization and typical changes in the gastrointestinal tract. The typical features of the process were the generalized immunomorphological reaction of the lymphoid apparatus with the appearance of light-colored reticulomacrophagal elements, the signs of the activation of humoral and cell-mediated immunity and the formation of small epitheloidocellular granulomas. The results of the investigation indicate that the stable cultures of S. typhi L-forms are highly pathogenic and capable of inducing the infectious process in experimental animals. 相似文献
60.