Effect of Root Temperature on Cytokinin Activity in Root Exudate of Vitis vinifera L

Root exudates of plants of Vitis vinifera L. cv. Thompson Seedless, grown in nutrient cultures with root temperatures maintained at either 20° or 30° and with shoots at a common air temperature, were assayed for cytokinin activity. After chromatography of freeze-dried sap on paper with n-butanol/acetic acid/water (4:1:1). activity was detected with a soybean callus assay. For both root temperatures, major activity appeared between R_F 0.6 and R_F 0.8, at about the same concentration in each case. The major difference between the 2 samples was the presence of activity at R_F 0.1 to 0.2 in the 20° sample and its absence in the 30° sample.

The higher root temperature resulted in increased shoot and root elongation, increased dry matter accumulation by both shoots and roots, and also altered the morphological appearance of the roots.

     

The Effect of cAMP on Phosphohydrolase Activity of the Barley Root Cells

We studied the effects of cAMP on phosphohydrolase activity in the microsomal fraction and its 0.5 M KCl extract. In both preparations, cAMP inhibited the activity of acid phosphatases. In the microsomal fraction, a 50% inhibition of acid cation-dependent (Mg²⁺, Cu²⁺) phosphatase was induced at pH 6.0 by 10 M cAMP; whereas, for cation-independent phosphatase, this effect was exerted only by 50 M cAMP. In the KCl extract, the sensitivity of both cation-dependent and cation-independent acid phosphatases to cAMP was higher than in the microsomal fraction. Cyclic AMP did not reduce the activity of nucleosidases. Selectivity in the cAMP action on acid phosphatases is assumed to be one of the mechanisms controlling the biochemical activity outside the barley root cells.     

土壤渍涝对芝麻根系生长及抗氧化物酶活性的影响

在渍水条件下芝麻根系生长速度下降,干物质积累减少,根系的抗氧化物酶--超氧物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)活性先增后下降,POD活性下降较缓慢,超氧自由由基(O·-2)产生速率和丙二醛(MDA)含量随淹水时间的延长而升高.     

Water Pumping Activity of the Root System in the Process of Cross-Adaptation of Sunflower Plants to Hyperthermia and Water Deficiency

To elucidate the mechanisms of cross-adaptation, we investigated the effect of heat shock (HS, for 2 h at 45°C) on leaf tolerance to overheating and exudation by roots detached from 25–30-day old sunflower (Helianthus annuus L.) plants. It was demonstrated that preheating enhanced considerably leaf tolerance and activated root exudation, especially under water deficiency produced by plant transfer to the hypertonic NaCl solution (17 mM). Under water deficiency conditions, the roots of HS-treated plants pumped water against the osmotic pressure (OP) gradient between the exudate and the external solution. Therefore, we concluded that this pumping was realized due to a metabolic (non-osmotic) constituent of root pressure. In the roots of plants that were not treated with HS, the OP gradient became positive. This fact implies that the HS-pretreatment of plants retarded the penetration of sodium and chlorine ions into roots. The data obtained demonstrate that HS induced a cross-adaptation of plants to high temperature and water deficiency. Such cross-adaptation involves, as an important component, an acceleration of water metabolism, including an enhanced water pumping activity of root system.     

The Effect of Tryptophan Present in Plant Root Exudates on the Phytostimulating Activity of Rhizobacteria

Aseptic tomato and radish roots were found to exude, respectively, 2.8–5.3 and 290–390 ng tryptophan per seedling per day. The inoculation of radish plants with rhizosphere pseudomonads increased the root biomass by 1.4 times. The inoculation of tomato plants with the same pseudomonads was ineffective. The beneficial effect of bacterial inoculation on the radish plants can be explained by the fact that the introduced rhizobacteria produce the plant growth–stimulating hormone indole-3-acetic acid. In pot experiments, the addition of this phytohormone to the soil increased the mass of radish roots by 36%. The phytohormonal action of the rhizosphere microflora was found to be efficient provided that the concentration of tryptophan in the rhizosphere is sufficiently high.     

Principal Component Analysis of Stimulatory Effect of Synbiotic Combination of Indigenous Probiotic and Inulin on Antioxidant Activity of Soymilk

Probiotics and Antimicrobial Proteins - The present study aimed to screen the indigenous probiotic cultures for their effect on total phenolic contents (TPC) and associated antioxidant activities...     

Adaptation of Active Proton Pumping and Plasmalemma ATPase Activity of Corn Roots to Low Root Medium pH

Corn (Zea mays L.) root adaptation to pH 3.5 in comparison with pH 6.0 (control) was investigated in long-term nutrient solution experiments. When pH was gradually reduced, comparable root growth was observed irrespective of whether the pH was 3.5 or 6.0. After low-pH adaptation, H⁺ release of corn roots in vivo at pH 5.6 was about 3 times higher than that of control. Plasmalemma of corn roots was isolated for investigation in vitro. At optimum assay pH, in comparison with control, the following increases of the various parameters were caused by low-pH treatment: (a) hydrolytic ATPase activity, (b) maximum initial velocity and Michaelis constant (c) activation energy of H⁺-ATPase, (d) H⁺-pumping activity, (e) H⁺ permeability of plasmalemma, and (f) pH gradient across the membranes of plasmalemma vesicles. In addition, vanadate sensitivity remained unchanged. It is concluded that plasmalemma H⁺-ATPase contributes significantly to the adaptation of corn roots to low pH. A restricted net H⁺ release at low pH in vivo may be attributed to the steeper pH gradient and enhanced H⁺ permeability of plasmalemma but not to deactivation of H⁺-ATPase. Possible mechanisms responsible for adaptation of plasmalemma H⁺-ATPase to low solution pH during plant cultivation are discussed.     

Properties of the Peribacteroid Membrane ATPase of Pea Root Nodules and Its Effect on the Nitrogenase Activity

Peribacteroid membrane vesicles from pea (Pisum sativum) root nodules were isolated from membrane-enclosed bacteroids by an osmotic shock. The ATPase activity associated with this membrane preparation was characterized, and its electrogenic properties were determined. The pH gradient was measured as a change of the fluorescence intensity of 9-amino-6-chloro-2-methoxyacridine and the membrane potential as a shift of absorbance of bis-(3-propyl-5-oxoisoxazol-4-yl)pentamethine oxonol. It was demonstrated that the ATPase generates a pH gradient as well as a membrane potential across the peribacteroid membrane. The reversibility of the ATPase was demonstrated by a light-dependent ATP synthesis by peribacteroid membrane vesicles fused with bacteriorhodopsin-phospholipid vesicles. The light-driven ATP synthesis by the peribacteroid membrane ATPase was completely inhibited by a proton-conducting ionophore. The proton-pumping activity of the peribacteroid membrane ATPase could also be demonstrated with peribacteroid membrane-enclosed bacteroids, and effects on nitrogenase activity were established. At pH values below 7.5, an active peribacteroid membrane ATPase inhibited the nitrogenase activity of peribacteroid membrane-enclosed bacteroids. At pH values above 8, at which whole cell nitrogenase activity was inhibited, the protonpumping activity of the peribacteroid membrane ATPase could partially reverse the pH inhibition. Vanadate, an inhibitor of plasma membrane and peribacteroid membrane ATPases, stimulated nodular nitrogenase activity. It will be proposed that the proton-pumping activity of the peribacteroid membrane ATPase in situ is a possible regulator of nodular nitrogenase activity.     

Acute Stimulatory Effect of Estradiol on Striatal Dopamine Synthesis

Abstract: The acute effect of physiological doses of estradiol (E2) on the dopaminergic activity in the striatum was studied. In a first series of experiments, ovariectomized rats were injected with 17α or 17β E2 (125, 250, or 500 ng/kg of body weight, s.c.), and in situ tyrosine hydroxylase (TH) activity (determined by DOPA accumulation in the striatum after intraperitoneal administration of NSD 1015) was quantified. A dose-dependent increase in striatal TH activity was observed within minutes after 17β (but not 17α) E2 treatment. To examine whether E2 acts directly on the striatum, in a second series of experiments, anesthetized rats were implanted in the striatum with a push-pull cannula supplied with an artificial CSF containing [³H]tyrosine. The extracellular concentrations of total and tritiated dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC) were measured at 20-min intervals. Addition of 10^?9M 17β (but not 17α) E2 to the superfusing fluid immediately evoked an ～50% increase in [³H]DA and [³H]DOPAC extracellular concentrations, but total DA and DOPAC concentrations remained constant. This selective increase in the newly synthesized DA and DOPAC release suggested that E2 affects DA synthesis rather than DA release. Finally, to determine whether this rapid E2-induced stimulation of DA synthesis was a consequence of an increase in TH level of phosphorylation, the enzyme constant of inhibition by DA (K_{i DA}) was calculated. Incubation of striatal slices in the presence of 10^?9M 17β (but not 17α) E2 indeed evoked an approximate twofold increase in the K_{i DA} of one form of the enzyme. It is concluded that physiological levels of E2 can act directly on striatal tissue to stimulate DA synthesis. This stimulation appears to be mediated, at least in part, by a decrease in TH susceptibility to end-product inhibition, presumably due to phosphorylation of the enzyme. The rapid onset of this effect, and the fact that the striatum does not contain detectable nuclear E2 receptors, suggest a nongenomic action of the steroid.     

Effect of Root Position on Measured Root Position on Measured Root Membrane Potentials

Root membrane potentials were measured by interposing a plantroot between two KCI solutions of different concentrations.The potentials measured across the two calomel electrodes werefound to depend on the position of the root. The potentialswere found to be lower when the root tip rather than the rootbase was in contact with the more concentrated solution. Thisindicates that the two parts of the root do not have the samein transport properties. Using an approximate theoretical treatmentthe observed potentials could be accounted for.     

Effect of Ethylene on the Increase in Catalase Activity through Microbody Development in Wounded Sweet Potato Root Tissue

Catalase activity increases when slices of sweet potato roottissue are incubated in air. The increase is due to de novosynthesis of the enzyme protein and probably also to activationof a precursor protein [Esaka et al. (1983) Plant & CellPhysiol. 24: 615]. The activity-increase was partly depressedwhen tissue slices were incubated in ethylenecontaining air,while the immunologically determined amount of catalase proteindid not increase, rather it decreased, under the same conditions.We propose that ethylene inhibits the de novo synthesis of catalaseprotein but not the activation of precursor protein. Catalasefrom tissue slices incubated in ethylene-containing air migratedfaster on a polyacrylamide gel than that from intact tissueor tissue slices incubated in air. When either polyacrylamideor an SDS-polyacrylamide gel applied with crude extract fromtissue slices incubated in ethylene-containing air underwentimmunological blotting, the blots were much fainter than thosefor intact tissue. In addition, microbody membrane fractionfrom incubated tissue slices contained a significant amountof catalase which was sedimented at the bottom of a sucrosedensity gradient (20–70%) and was not solubilized by highconcentrations of lubrol PX. The fraction showed an exceptionallyhigh catalase activity per unit amount of immunoreactive proteinto anti-catalase antibody. We propose that ethylene causes somemodification of catalase protein which facilitates the formationof aggregates or cores. ¹Present address: Laboratory of Food Technology, Faculty ofApplied Biological Science, Hiroshima University, Fukuyama,Hiroshima 720, Japan. ²Present address: Terumo Co. Ltd., Omiya, Fujinomiya, Shizuoka418, Japan. (Received October 16, 1982; Accepted February 24, 1983)     

Stimulatory Effect of Epinephrine on Biofilms of Micrococcus luteus C01

Microbiology - This is the first report on biofilm formation by Micrococcus luteus C01 in model systems stimulated by epinephrine. In the presence of 900 pg/mL of epinephrine in the medium, a 52.3%...     

The Effect of Coumarin on Root Growth and Root Histology

The effect of coumarin on the root growth was studied on roots from intact plants, isolated roots and isolated elongating zones. All material was cultivated aseptically. A new method was developed for sterile culture of intact plants in flowing nutrient medium. The effects on cell division and cell elongation were studied separately. An effect on both these processes can be established at all concentrations that affect the root growth. The concentration-growth curve has an “all-or-none” appearance. Coumarin inhibits the transverse divisions in all cell layers; the perivascular layers seem to be more sensitive. Also the mitotic activity that is involved in the initiation of laterals is inhibited. The longitudinal divisions within the stele are enhanced. Coumarin decreases the cell length in all cell layers, most likely with greater relative sensitivity in the perivascular layers. Studies on the time course of cell elongation in both attached corn roots and isolated elongating zones reveal that the decrease in cell length is caused exclusively by a decrease in the maximal rate of elongation, whereas the duration of the elongation is unchanged. With each decrease of the cell length, the cell diameter is increased. The two changes are intimately connected within the greater part of the active region of concentration. Studies on the time course of the radial expansion in isolated elongating zones show a strict connection in time between cell elongation and radial expansion. The radial expansion leads to unchanged or increased cell volume at most concentrations and for most cell types. Coumarin causes an inhibition of the longitudinally directed processes and a stimulation of the radially directed ones. This is interpreted as indicating that the formative system is disengaged or reorientated, i.e., the polarity of the cells is changed. Through experiments partly with isolated elongating zones and partly by disruption of the linear phase by means of mannitol, the inhibitory effect of coumarin could be localized to the first non-linear phase of the elongation. The results were compared with earlier findings in the literature. The microtubuli are proposed as a conceivable main Component in the formative system common to both cell division and cell elongation. These are assumed to be affected by changes in the SH/SS balance produced by coumarin.     

Simultaneous and Dose Dependent Melanoma Cytotoxic and Immune Stimulatory Activity of Betulin

Conventional cytostatic cancer treatments rarely result in the complete eradication of tumor cells. Therefore, new therapeutic strategies focus on antagonizing the immunosuppressive activity of established tumors. In particular, recent studies of antigen-loaded dendritic cells (DCs) eliciting a specific antitumor immune response has raised the hopes of achieving the complete elimination of tumor tissue. Genistein, fingolimod and betulin have already been described as active compounds in different types of cancer. Herein, we applied an integrated screening approach to characterize both their cytostatic and their immune-modulating properties side-by-side. As will be described in detail, our data confirmed that all three compounds exerted proapoptotic and antiproliferative activity in different B16 melanoma cell lines to a given extent, as revealed by an MTT assay, CFSE and DAPI staining. However, while genistein and fingolimod also affected the survival of primary bone marrow (BM) derived DCs of C57BL/6 mice, betulin exhibited a lower cytotoxicity for BMDCs in comparison to the melanoma cells. Moreover, we could show for the first time, that only betulin caused a simultaneous, highly specific immune-stimulating activity, as measured by the IL-12p70 release of Toll-like receptor 4-stimulated BMDCs by ELISA, which was due to increased IL-12p35 mRNA expression. Interestingly, the activation of DCs resulted in enhanced T lymphocyte stimulation, indicated by increased IL-2 and IFN-γ production of cytotoxic T cells in spleen cell co-culture assays which led to a decreased viability of B16 cells in an antigen specific model system. This may overcome the immunosuppressive environment of a tumor and destroy tumor cells more effectively in vivo if the immune response is specific targeted against the tumor tissue by antigen-loaded dendritic cells. In summary, cytostatic agents, such as betulin, that simultaneously exhibit immune stimulatory activity may serve as lead compounds and hold great promise as a novel approach for an integrated cancer therapy.     

Stimulatory Effect of Aspartic Acid on Colistin Production by Bacillus polymyxa

The effect of amino acids on colistin production was investigated with Bacillus polymyxa var. KY-7584. Aspartic acid, the precursor of α,γ-diaminobutyric acid (one of the structural components of colistin), showed a remarkable difference of colistin production between Morido’s fermentation medium and the modified medium containing the appropriate concentrations of phosphate ion (PO₄^3-) and ammonium-nitrogen (NH₄-N). Further studies revealed that a main factor which controlled the stimulatory effect of aspartic acid on colistin production was PO₄^3- . The optimum concentrations of aspartic acid, PO₄^3- and NH₄-N in the medium for colistin production were above 0.2%, below 0.01% and 0.17%, respectively. The maximum titer of colistin (51,900 u/ml) by the addition of 0.25% aspartic acid showed the increment of about 30% as compared with that in the reference medium. However, the increase of cell concentration was slight. This study also showed that PO₄^3- was an effector to inhibit the metabolic pathwy from aspartic acid to α,γ-diaminobutyric acid.     

板蓝根多糖对中华鳖小肠抗氧化酶活性和脂质过氧化的影响

研究了腹腔注射板蓝根多糖(IRPS)对中华鳖小肠抗氧化酶活性和脂质过氧化的影响.24只中华鳖分成4组,每天注射1.5 mg/只、 3 mg/只、 6 mg/只处理组和注射生理盐水对照组,连续注射3 d.结果 表明,3个IRPS处理组均能显著提高SOD、GSH-PX酶活性,极显著降低MDA含量,而且小肠SOD活性随注射剂量的增大而增强,MDA含量随注射剂量的增大而降低.3 mg/只注射组对GSH-PX酶活性提高最显著,1.5 mg/只剂量组能显著提高CAT酶活性,但3 mg/只、 6 mg/只剂量组对CAT酶活性无显著性影响.     

Developmental Changes in the NAD Content in Sugar-Beet Root Mitochondria and Their Effect on the Oxidative Activity of These Organelles

The NAD content was determined in mitochondria isolated from sugar-beet roots at various stages of plant development. A high NAD content (7.6 ± 0.9 nmol/mg mitochondrial protein) was observed in the mitochondria of actively growing roots of 80–95-day-old plants, but it decreased ca. twofold by the end of the first year of plant development, before the roots were harvested for storage. The mitochondria isolated from roots stored at low temperature for two to three months and those after five to eight days of regrowth during the second year of plant development manifested an even lower NAD content (2.2 ± 0.4 and 2.0 ± 0.5 nmol/mg protein, respectively). A drastic decrease in the NAD content in mitochondria from stored roots did not result from the impairment of the inner membrane of these organelles and was evidently regulatory in its nature. The effect of developmental changes in the intramitochondrial NAD content on the malate oxidation pattern was studied. In the mitochondria of stored roots, the low NAD content limited the rate of malate oxidation in state 3, because the addition to the reaction mixture of exogenous NAD, which can be transported to the mitochondrial matrix, promoted malate oxidation by 30–50%. Rotenone inhibited malate oxidation in the stored-root mitochondria by more than 70%; in this case, the rate of rotenone-resistant malate oxidation in these organelles increased by several times in the presence of exogenous NAD. In the mitochondria of the growing root, exo-genous NAD did not affect the rate of malate oxidation, and rotenone inhibited it only by 25–35%. The analysis of the data obtained here and the published evidence suggests the existence of a universal mechanism of respiration control and the regulation of the functional activity of plant mitochondria. This mechanism acts through a change in the NAD content in the organelle matrix. This NAD can be used in the course of plant development, e.g., during the transition of sugar-beet-root cells in the dormant state, when the respiration rate must decline.     

胡杨液泡膜微囊H^＋—ATPase质子泵活性研究

将悬浮培养的胡杨 (PopuluseuphraticaOliv .)细胞捣碎后 ,通过差速离心和不连续蔗糖密度梯度离心获得富集液泡膜的膜微囊。通过连续监测吖啶橙的荧光淬灭研究膜微囊上H _ATPase的质子转运特性。结果表明 ,质子转运依赖于ATP ,其表观米氏常数Km 值为 0 .6 5mmol/L。质子泵活性受pH和温度的影响较大。测定液pH值为7.5时 ,质子泵的活性最高 (测定温度选定为 2 2℃ )。一些二价阳离子可启动H _ATPase的质子转运 ,其中Mg2 的作用远高于Fe2 。在实验条件下 ,Ca2 、Cu2 和Zn2 均不能启动H _ATPase的质子转运。质子跨膜转运还可被一价阴离子激活 ,激活作用的顺序为 :Cl->Br->I->F-。质子泵活性受NEM(乙基马来酰亚胺 )、DCCD (二环己基碳二亚胺 )、NO-3 和BafilomycinA1的强烈抑制 ,但对Na3VO4 和NaN3 不敏感。这些性质说明胡杨液泡膜微囊上的H _ATPase属于囊泡型的ATPase。