Abstract：
:The hydrolytic activity and interaction of acidic and neutral phospholipase A2 (PLA2) with large unilamellar liposomes treated with cobra venom cytotoxin Vc5 (CT Vc5) were studied to more fully understand the modulating effects of cationic membrane-active peptides on PLA2. Studies were done by fluorescence displacement, EPR spin probes, and 31P-NMR. The results showed that CT Vc5 inhibits PLA2 activity on phosphatidylcholine liposomes. Enzymatic activity of both acidic and neutral PLA2's were enhanced on liposomes containing cardiolipin and pretreated with cytotoxin. The cytotoxin, however, inhibited enzyme lipid hydrolysis if these same liposomes were first treated with acidic PLA2. The highest enzymatic activity was found on substrates with nonbilayer lipid packing. Using EPR of spin labeled enzymes, it was shown that CT Vc5 inhibited binding of acidic PLA2 to liposomes and caused displacement of acidic PLA2 from liposomes. No direct interaction was found between CT Vc5 and neutral PLA2.. It is suggested that cytotoxin perturbs packing of lipid molecules in liposomes containing cardiolipin and is responsible for increased catalysis, whereas direct interaction between CT Vc5 and acidic PLA2, inhibits enzyme activity. It is concluded that variability in substrate composition and the chemical nature of both PLA2 and cationic peptide determine whether enzyme activity is affected by substrate packing or by direct enzyme-peptide interaction. Models of interactions of PLA2 with CT Vc5 and phospholipid membranes are presented.
journal_name
Gen Physiol Biophysjournal_title
General physiology and biophysicsauthors
Gasanov SE,Gasanov NE,Rael EDsubject
Has Abstractpub_date
1995-04-01 00:00:00pages
107-23issue
2eissn
0231-5882issn
1338-4325journal_volume
14pub_type
杂志文章abstract：:The effects of different parts of extract from medicinal plant Conyza canadensis, used to control bleeding, on human blood platelet aggregation in vitro were investigated. Aqueous extract of Conyza c. from young or old plants, glycoconjugate part, polysaccharide part and aglycon part at the concentrations above 0.75 m...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：
更新日期：2007-06-01 00:00:00
abstract：:The relationship between erythrocyte shape and the critical cell volume was investigated. Agents able to increase the critical cell volume induced three main stable shapes of erythrocytes: discocytic, stomatocytic, and echinocytic. The absence of correlation between shape and critical cell volume under isoosmotic cond...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：
更新日期：1992-10-01 00:00:00
abstract：:The effect of hydroxyl radicals generated by the FeSO4/H2O2 system on structural properties of proteins and membranes was studied in rat cardiac mitochondria and myofibrils. Exposure of mitochondria to 0.1 mmol/l FeSO4/EDTA plus 1 mmol/l H202 at 37 degrees C for 30 or 60 min caused conjugated diene formation, but it w...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：
更新日期：2004-09-01 00:00:00
abstract：:Electron spin resonance spectroscopy (ESR) was used to study the effects of amphiphilic amines of the carbamate, amide, and ester type and amine oxide on the photosynthetic system of spinach chloroplasts. The ESR signal II connected to the photosynthetic center PS II donor side was observed to diminish in the presence...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：
更新日期：1990-12-01 00:00:00
abstract：:This study investigated time-dependent variations in the activities of adenosine deaminase (ADA), an adenosine-metabolizing enzyme, and myeloperoxidase (MPO), an oxidation reaction-catalyzing enzyme, in control and streptozotocin (STZ)-induced diabetic rat liver. The animals were sacrificed at six different times of d...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：
更新日期：2008-03-01 00:00:00
abstract：:The effects of alamethicin on the membrane barrier function of rabbit erythrocytes, human platelets and sarcoplasmic reticulum vesicles, as well as on that of brain microsomes and liver mitochondria of the rat were compared. An upset of the barrier function was observed for plasma membranes of brain microsomes as well...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：
更新日期：1992-02-01 00:00:00
abstract：:The human pituitary tumor-transforming gene-1 (hPTTG1) has been found to be overexpressed in various cancers. Accumulated evidences implicate that some of protein kinases can specifically recognize two PXXP motifs at hPTTG1 C-terminus through their Src homology (SH3) domain and then phosphorylate the protein by their ...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：10.4149/gpb_2016035
更新日期：2017-01-01 00:00:00
abstract：:Sleep is considered as a physiological regulator in the body. Gamma-aminobutyric acid (GABA) is a neurotransmitter that modulates sleep and affects cardiac functions. We evaluated effects of acute sleep deprivation (SD) on cardiac hemodynamic parameters, expression of pro-inflammatory cytokines, and Heat shock protein...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：10.4149/gpb_2017049
更新日期：2018-05-01 00:00:00
abstract：:The capacity of five synthetic analogs of [8-arginine] vasopressin (AVP) to stimulate frog skin sodium transport (natriferic activity) was characterized electrophysiologically using the method of short-circuit current, and compared to that of synthetic AVP. The analogs used were [8-arginine] vasopressins modified in p...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：
更新日期：1990-12-01 00:00:00
abstract：:The voltage dependent ionic currents in cultured embryonic skeletal myocytes at stages of development ranging from 1 to 6 day were studied using the whole-cell patch clamp technique. Sodium (INa) and calcium (ICa) inward and potassium (IK) outward currents were observed at all stages. INa did not differ from that desc...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：
更新日期：1993-06-01 00:00:00
abstract：:Inhibition of angiogenesis involves blocking of tyrosine kinases (TK) implicated in signalling of vascular endothelial growth factor receptors (VEFGR). The inhibition of TK results in a disruption of Ras/Raf/MEK/ERK1/2 and PI3K/Akt signalling pathways. We evaluated recently developed TK inhibitor 22SYM and compared it...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：10.4149/gpb_2015055
更新日期：2016-10-01 00:00:00
abstract：:Hyperlipidemia is found to be associated with changes in fatty acid (FA) profiles. The aim of this study was to investigate the effects of AHA-Step-1 dietary treatment and combination of fibrates (gemfibrozil) with dietary intervention on serum and erythrocyte phospholipid FA composition in human hyperlipidemia. 78 st...
journal_title：General physiology and biophysics
pub_type： 临床试验,杂志文章
doi：
更新日期：2009-01-01 00:00:00
abstract：:Stationary and time-dependent fluorescence were measured for a donor/ acceptor (DA) pair bound to membrane proteins of bovine erythrocyte ghosts. The donor N-(p-(2-benzoxazolyl)phenyl)-maleimide (BMI) and the acceptor fluram bind to SH- and NH2-residues, respectively. The fluorescence spectra and the time-dependent em...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：
更新日期：1997-03-01 00:00:00
abstract：:Activated endothelial cells play a crucial role in the formation of new blood vessels, a process known as angiogenesis, which can underlie the development of several diseases. Different antiangiogenic therapies aimed against vascular endothelial growth factor (VEGF), the dominant pro-angiogenic cytokine, have been dev...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：10.4149/gpb_2018047
更新日期：2019-03-01 00:00:00
abstract：:The activity of different cathepsins and neutral proteinases was measured in normal and vitamin E-deficient rabbit muscles using specific substrates. Among the changes of enzyme activities in dystrophy caused by vitamin E-deficiency the increase in the activity of cathepsin B is the most striking. The activity of cath...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：
更新日期：1991-10-01 00:00:00
abstract：:Lignin, the structural polymer of the plant cell walls, is produced by free radical polymerization of phenolic alcohols, catalyzed by different peroxidases. The mechanism and the structural organization of lignin in the cell have not been completely understood. In this study we applied fractal analysis to images of li...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：
更新日期：2000-06-01 00:00:00
abstract：:This study was designed to investigate the possible effectiveness of chronic resveratrol administration on redox state, inflammatory mediators and apoptosis rate in diabetic rats. Male Wistar rats were divided into four groups (n = 6): normal control, diabetic control, normal rats treated with resveratrol, and diabeti...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：10.4149/gpb_2012_039
更新日期：2012-12-01 00:00:00
abstract：:The hyperpolarisation of the membrane potential in Characeae above that of the diffusion potential is explained by the operation of the electrogenic proton pump. We studied the interaction of calcium with the functioning of the pump. The membrane potential was measured using the standard microelectrode technique. An i...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：
更新日期：1985-04-01 00:00:00
abstract：:Voltage-activated calcium channels can be divided into two subgroups based on their activation threshold, low-voltage-activated (LVA) and high-voltage-activated (HVA). Auxiliary subunits of the HVA calcium channels contribute significantly to biophysical properties of the channels. We have cloned and characterized mem...
journal_title：General physiology and biophysics
pub_type： 杂志文章,评审
doi：
更新日期：2005-06-01 00:00:00
abstract：:The aim of the present study was to investigate the ability of the chloroacetanilide herbicide acetochlor to interact with the endocrine system. The modulation of the binding of [3H]estradiol-17beta to protamine sulphate-precipitated uterine nuclear and cytoplasmic estrogen receptors was analysed for this purpose. Two...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：
更新日期：2000-03-01 00:00:00
abstract：:Myosin was isolated from pig atrial and ventricular myocardium during postnatal development and Ca2+-ATPase was determined and myosin light chains were analysed by electrophoresis in sodium dodecylsulfate polyacrylamide gel. During ontogenesis ATPase activity of ventricular myosin remains virtually unchanged, whereas ...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：
更新日期：1989-02-01 00:00:00
abstract：:Effects of six thiol reagents with different physico-chemical properties were tested on the Na+-dependent 45Ca2+ transport into the rat brain microsomal membrane vesicles. The mercurials p-chlormercuribenzoate and Mersalyl effectively inhibited 45Ca2+ uptake with IC50 values in the order of 10(-4) mol X l-1 in the med...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：
更新日期：1987-04-01 00:00:00
abstract：:The existence of a high-conductance voltage sensitive chloride channel in BC3H1 myoblasts is documented. The conductance of the channel in symmetrical 150 mmol/l sodium chloride is around 400 pS. The probability of the channel being in the open state decreases with increasing of the imposed voltage from holding potent...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：
更新日期：1993-04-01 00:00:00
abstract：:On the basis of values corresponding to concentrations exhibiting 50% inhibition of platelet aggregation induced with different stimuli and 50% inhibition of arachidonic acid liberation and thromboxane generation, we compared the antiplatelet effect of two cationic amphiphilic drugs--chloroquine and dithiaden. Compare...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：
更新日期：1999-10-01 00:00:00
abstract：:The effect of membrane composition on ethanol partitioning into lipid bilayers was assessed by headspace gas chromatography. A series of model membranes with different compositions have been investigated. Membranes were exposed to a physiological ethanol concentration of 20 mmol/l. The concentration of membranes was 2...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：10.4149/gpb_2009_02_140
更新日期：2009-06-01 00:00:00
abstract：:It is well known that in vitro storage lesions lead to membrane dysfunction and decreased number of functional erythrocytes. As erythrocytes get older, in storage media as well as in peripheral circulation, they undergo a variety of biochemical changes. In our study, the erythrocytes with different age groups in citra...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：10.4149/gpb_2016001
更新日期：2016-07-01 00:00:00
abstract：:Fasting for 48 h and the same period of recovery induced by 48 h refeeding increased rat hypothalamic monoamine oxidase (MAO) activity. However, in the interscapular brown adipose tissue (IBAT), only refeeding induced a significant elevation of the enzyme activity. As far as hypothalamic antioxidative enzymes are conc...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：
更新日期：2000-09-01 00:00:00
abstract：:Elevated serum resistin is implicated in insulin resistance associated with obesity and type 2 diabetes mellitus. Alcohol consumption interferes with the nutritional status, metabolic and hormonal activity of the drinker. Impact of ethanol intake on resistin level and resistin metabolic effects is unknown. Effect of l...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：
更新日期：2007-09-01 00:00:00
abstract：:Ischemic and reperfusion injury is a serious condition related to numerous biochemical and electrical abnormalities of the myocardium. It has been repeatedly studied in various animal models. In this study, the production of hydroxyl radicals and electrophysiological parameters were compared in three species. Rat, gui...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：10.4149/gpb_2013016
更新日期：2013-06-01 00:00:00
abstract：:Semiserial sections of lung capillaries of seven rabbits were examined for megakaryocytes. Triads of serial sections of each lobe were examined, and megakaryocyte counts per cm2 were determined. Median megakaryocyte count was determined for each lobe. The lobal values were used to calculate the was determined for each...
journal_title：General physiology and biophysics
pub_type： 杂志文章
doi：
更新日期：1987-08-01 00:00:00
