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951.
The multitest V. cholerae medium (VC medium) for rapid presumptive identification of Vibrio cholerae was evaluated. On the basis of reactions in the VC medium, 379 strains recovered during a yearlong ecological study in Calcutta were presumptively identified as V. cholerae. Further phenotypic characterization of these strains revealed that the reactions of 371 (97.9%) isolates were consistent with that of V. cholerae. False-positive reactions were exhibited by eight (2.1%) strains, three of which were identified as Vibrio fluvialis biotype 1. By slightly varying the basic formulation of the VC medium, we could eliminate some false-positive reactions. On the basis of the present evaluation, we recommend the routine use of the VC medium. 相似文献
952.
Mature endosperm tissue excised from germinated seeds (2–4 days after radicle emergence) of Annona squamosa grew and proliferated on White's basal medium supplemented with two cytokinins, an auxin and gibberellic acid. The callus obtained could be periodically subcultured. Shoot differentiation and root induction were obtained from callus on media of different compositions. Analyses of the root and young leaf tips showed triploid number of chromosomes (3n=21).Abbreviations Kin
Kinetin
- BAP
6-Benzylaminopurine
- IAA
Indole-3-acetic acid
- IBA
Indole-3-butyric acid
- NAA
naphthalene abetic acid
- GA3
Gibberellic acid
Communication No. 3885 相似文献
953.
O2 microelectrode measurements were made in the cat carotid body (CB) at normal control blood pressures (C) and after hemorrhage (H) to reduce mean arterial blood pressure [C, 98.7 +/- 4.6 (SE) mmHg; H, 58.1 +/- 1.8; P less than 0.001; paired t test; n = 9 cats]. Mean tissue PO2 (PtiO2) was significantly lower (C, 78.4 +/- 3.0 Torr; H, 65.3 +/- 4.8; P less than 0.01). Except for two experiments with good autoregulation, the decrease in PtiO2 correlated with the reduction in blood pressure (r = 0.791, P less than 0.005). Measurements of O2 disappearance curves (DCs) and sinus nerve discharge (ND) were obtained after blood supply was occluded for 30-45 s (56 C DCs, 44 H DCs). Disappearance rates (dPO2/dt) were significantly slower after hemorrhage (C, -7.52 +/- 0.47 Torr/s; H, -6.60 +/- 0.44; P less than 0.01), decreasing by 0.656 Torr/s for each 10 Torr fall in PtiO2 (r = 0.626, P less than 0.05). Resting ND before occlusion increased during hypotension (11.6 +/- 2.9% of control, P less than 0.01) and correlated with the decrease in PtiO2 (r = -0.792, P less than 0.005). A computer simulation was performed for a two-cytochrome metabolic model with a second, low-O2-affinity oxidase in addition to normal oxidative metabolism. The effects of cat oxyhemoglobin and blood pH on the O2 DC measurement were also taken into account. The simulation for the two-cytochrome model was consistent with our experimental data and predicts reductions in blood flow and O2 metabolism with hypotension after hemorrhage that have similarities, as well as aspects that disagree, with previous reports in the literature. 相似文献
954.
Y. Li K. Y. Cho Y. Z. Wu N. G. Nair 《World journal of microbiology & biotechnology》1992,8(6):621-626
Vegetable oils promoted mycelial growth ofVolvariella volvacea. Ethyl esters of major components of saponified fatty acids (palmitic, stearic, oleic and linoleic acid) from vegetable oils were stimulatory. The stimulatory effect of these fatty acids varied with concentration and degree of unsaturation; relatively high concentrations being inhibitory. Mycelial growth appears to be promoted by low concentrations of fatty acids. Supplementation of growth medium with sunflower oil altered membrane permeability and this resulted in an increased uptake of glucose. The total mycelial lipids accounted for only 30% of consumed lipids, the remainder being metabolized. The failure of the fungus to adjust the degree of unsaturation in membrane lipids when it was transferred to 0°C may partially explain its susceptibility to chilling injury. 相似文献
955.
A detailed account of the structure and musculature of the mouth tube and mode of feeding in P. narcinae is presented. The double-walled mouth tube is formed by a close fitting of the lateral, longitudinal ridges of the labium into the longitudinal groove of the inner, lateral edges of the labrum. The musculature of the mouth tube consists of two pairs of retractores oris, four pairs of compressores labri and two pairs of levatores labii. The host tissues are scraped off by the mandibles repeating a very characteristic movement brought about by roto adductor mandibulae and roto abductor mandibulae pair of muscles. The tissue particles are forced into the buccal cavity with the help of labral muscles. The suction is broken by the contraction of levatores labii group of muscles. 相似文献
956.
Evidence for an organic cation-proton antiport system in brush-border membranes isolated from the human term placenta 总被引:1,自引:0,他引:1
V Ganapathy M E Ganapathy C N Nair V B Mahesh F H Leibach 《The Journal of biological chemistry》1988,263(10):4561-4568
Uptake of guanidine, an endogenous organic cation, into brush-border membrane vesicles isolated from human term placentas was investigated. Initial uptake rates were manyfold greater in the presence of an outward-directed H+ gradient ([pH]o greater than [pH]i) than in the absence of a H+ gradient ([pH]o = [pH]i). Guanidine was transiently accumulated inside the vesicles against a concentration gradient in the presence of the H+ gradient. The H+ gradient-dependent stimulation of guanidine uptake was not due to a H+-diffusion potential because an ionophore (valinomycin or carbonylcyanide p-trifluoromethoxyphenylhydrazone)-induced inside-negative membrane potential failed to stimulate the uptake. In addition, uphill transport of guanidine could be demonstrated even in voltage-clamped membrane vesicles. The H+ gradient-dependent uptake of guanidine was inhibited by many exogenous as well as endogenous organic cations (cis-inhibition) but not by cationic amino acids. The presence of unlabeled guanidine inside the vesicles stimulated the uptake of labeled guanidine (trans-stimulation). These data provide evidence for the presence of an organic cation-proton antiporter in human placental brush-border membranes. Kinetic analysis of guanidine uptake demonstrated that the uptake occurred via two saturable, carrier-mediated transport systems, one being a high affinity, low capacity type and the other a low affinity, high capacity type. Studies on the effects of various cations on the organic cation-proton antiporter and the Na+-H+ exchanger revealed that these two transport systems are distinct. 相似文献
957.
K. P. Prabhakran Nair 《Plant and Soil》1984,81(2):209-215
Summary As Electro-Ultra-Filtration offers the possibility for a rapid measurement of the intensity parameter of plant nutrients, it was examined whether or not the integration of the buffer power would improve information generated, by this technique and so an experiment was conducted to answer this question of the importance of Zn buffer power on Zn nutrition of maize. The experimental soil was dressed with graded amounts of soluble Zn and equilibrated for 15 days after which separate portions of it were extracted with DTPA to determine Zn quantity and by the Electro-Ultra-Filtration technique (EUF) to determine Zn intensity. The same soil was cropped to maize to monitor Zn uptake. At first Zn concentration in the plant top, determined by inductively coupled plasma emission spectrophotometry, and total Zn uptake by plant top, were correlated with the Electro-Ultra-Filtrable zn at seeding and at harvest as simple linear regression functions. When the corresponding Zn buffer power was also integrated into the computations as a multiple regression function, there was a remarkable improvement in the correlation coefficients so obtained and as much as 66% of the variance in Zn concentration in the plant top could be attributed to the variance in Zn intensity and the corresponding Zn buffer power. The Zn buffer power measures the rate of Zn replenishment around plant roots during crop growth. Since the EUF technique offers the possibility for rapid measurement of Zn intensity, the predictability of routine soil testing by this method could be substantially enhanced by integrating the Zn buffer power also into the computations. 相似文献
958.
Jean?Paulo?de?Andrade Raquel?B.?Giordani Laura?Torras-Claveria Natalia?Belén?Pigni Strahil?Berkov Mercè?Font-Bardia Teresa?Calvet Eduardo?Konrath Kelly?Bueno Liana?G.?Sachett Julie?H.?Dutilh Warley?de?Souza Borges Francesc?Viladomat Amelia?T.?Henriques Jerald?J.?Nair José?Angelo?S.?Zuanazzi Jaume?BastidaEmail author 《Phytochemistry Reviews》2016,15(1):147-160
Nine Brazilian Amaryllidaceae species were studied for their alkaloid composition and acetylcholinesterase (AChE) inhibitory activity via GC–MS and a modified Ellman assay, respectively. A total of thirty-six alkaloids were identified in these plants, of which Hippeastrum papilio and H. glaucescens exhibited the highest galanthamine content and the best IC50 values against AChE. Furthermore, Hippeastrum vittatum and Rhodophiala bifida also showed notable AChE inhibitory effects. X-ray crystallographic data for four galanthamine-type compounds revealed significant differences in the orientation of the N-methyl group, which are shown to be related to AChE inhibition. 相似文献
959.
A series of Na15(SO4)5F4Cl phosphors doped with Ce3+ ions was prepared using the wet chemical method. X‐Ray diffraction studies were used to determine their phase formation and purity. Fourier transform infrared spectroscopy effectively identified the chemical bonds present in the molecule. The photoluminescence properties of the as‐prepared phosphors were investigated and the Ce3+ ions in these hosts were found to give broadband emission in the UV range. For the thermoluminescence study, phosphors were irradiated with a 5 Gy dose of γ‐rays from a 60Co source. Chen’s half‐width method was employed to calculate the trapping parameters from the thermoluminescence glow curve. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
960.
Beena Elizabeth Thomas Banurekha Velayutham Kannan Thiruvengadam Dina Nair Sukendu Bikas Barman Lavanya Jayabal Senthanro Ovung Soumya Swaminathan 《PloS one》2016,11(1)