首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
We describe a fluorescent histochemical technique for detection of nonspecific alkaline phosphatase (APase) in cells. The technique utilizes standard azo dye chemistry with naphthol AS-MX phosphate as substrate and fast red TR as the diazonium salt. The reaction product is a highly fluorescent red precipitate. Pre-implantation mouse embryos were used to establish optimal fixation and staining protocols and the specificity and sensitivity of the method. Fixation was in 4% paraformaldehyde for 1 hr, as glutaraldehyde induced autofluorescence of the cells. Maximal discriminable staining was detected after 15-20 min in the stain solution. The stain solution itself proved to be non-fluorescent, thus allowing visual observation of the progress of the staining reaction by fluorescence microscopy in its presence. To test the specificity of this fluorescent APase stain, a variety of cell types of known APase reactivity were stained by this protocol. Mouse lymphocytes and STO fibroblasts were negative, whereas F9 teratocarcinoma cells, intestinal epithelial cells, and rat fetal primordial germ cells were all found to be highly positive for APase activity, in agreement with published results on APase localization in these cells.  相似文献   

2.
Summary Fixation of cells with glutaraldehyde (5.0%, pH 6.7) was found to facilitate both the penetration of substrate (p-nitrophenyl phosphate) into cells and the leaking out of intracellular phosphate ions. 64% of the original activity survived the fixation for at least 24 hours. Lead ions added to the incubation medium at 6 mM neither accelerated nonenzymatic hydrolysis of the substrate, nor completely inactivated the enzyme activity. Lead ions at concentrations above 6 mM formed an insoluble compound with p-nitrophenyl phosphate, resulting in a decrease in the concentration of free substrate and lead ions. Phosphate ions liberated from substrate could not be completely trapped by lead ions even at above 6 mM, suggesting the possibility of intracellular migration of phosphate ions.In the presence of 4 mM p-nitrophenyl phosphate, 6 mM lead nitrate, and 0.2 M sucrose at pH 6.5, lead salt precipitates were deposited on the outer surface of cell walls, within cell walls, at tonoplast membranes, in nuclei, and occasionally in proplastids. No deposition of lead salt was formed in the control test from which the substrate was omitted. When cells were treated at first with lead nitrate and then with potassium phosphate, lead salt deposits were formed in the same sites as those of cells incubated in a complete reaction medium.It is concluded that although the result of the lead salt precipitation procedure reflects the presence of enzyme activity, it cannot directly show the site of the enzyme.  相似文献   

3.
Synopsis Acid phosphatase activity is demonstrated employingp-nitrophenyl phosphate as substrate and lead acetate as coupler. The fine structural localization of the enzyme in starved planarian tissues is described. The method is used to pin-point starvation-induced acid phosphatase activity in relation to autophagy and crinophagy in the gland cells; autophagy, autolysis and cell death in parenchymal and gastrodermal cells and basement membrane lysis. Attention is also payed to the demonstration of muscle lysis. The histochemical implications of the method are discussed.  相似文献   

4.
A microbial method to determine sulphate concentration in water was developed on the basis of sulphate-dependent acid phosphatase (APase) in whole cells of Thiobacillus thiooxidans. The activity of the APase was determined colorimetrically by using p-nitrophenylphosphate as substrate. The APase was activated by sulphate. A linear relationship was obtained between the activity of the APase and the concentration of sulphate in the range 0–0.6 mM. Therefore, the sulphate concentration was estimated from the APase activity, represented by the absorbance (A 400). The microbial method was applied to the determination sulphate in water. The lower limit of detection was 0.02 mM, the relative standard deviation being 2% for 10 measurements on a standard sample. As for practical samples, which were taken from rain, river and tap water, good agreement was obtained between the values measured by the microbial method and those given by a conventional barium chloranilate method. The relative standard deviation was 2.1% for 12 measurements of tap water. The activity of the APase was stable over a period of more than 100 days when the cells were stored in 0.1 M sodium acetate/acetic acid buffer (pH 5.0) at 4 °C. Received: 21 March 1997 / Received revision: 30 June 1997 / Accepted: 27 July 1997  相似文献   

5.
The light microscopic histochemical localization of alkaline phosphatase (APase) and adenosine triphosphatase (ATPase) in the mammalian pancreas is reviewed. Capillary endothelial cells usually exhibit both enzymes. ATPase is usually present in endocrine and acinar cells and absent in duct cells. APase is often found in islet cells but is almost always absent in exocrine cells. These enzymes should therefore be used with caution as markers for specific cells and organelles of the pancreas, and for monitoring diseases that might lead to the release of these enzymes from the pancreas.  相似文献   

6.
 There is strong evidence that acid phosphatase (AcPase) plays an important role in the catabolism of the glomerular basement membrane (GBM) and the removal of macromolecular debris resulting from ultrafiltration. Recent enzyme histochemical investigations provide new evidence of the antithrombotic and anti-inflammatory function of ADPase and on the distribution of AcPase in mouse kidney tubule cells. By means of 3 mM cerium as the trapping agent and 1 mM p-nitrophenyl phosphate as the substrate, extralysosomal AcPase could be demonstrated at the ultrastructural level. Following a mild perfusion fixation (2% formaldehyde + 0.07% glutaraldehyde), an effective postfixation and short enzyme incubations (20 min) with microwave irradiation, highly specific enzyme histochemical reaction product and reasonable structural preservation were obtained. Extralysosomal, membrane-bound AcPase was observed along the endoplasmic reticulum, the trans-Golgi cisternae, the nuclear envelope, basal infoldings of the proximal and distal tubular cells and on glomerular profiles, e.g. cell membranes of podocytes, endothelium and basement membrane. Large amounts of extralysosomal AcPase were observed in the basement membrane of glomeruli, in contrast to no AcPase activity in the tubular and mesangial basement membrane. The observed difference in AcPase activity in the tubular epithelial basement membrane and the GBM supports the idea that AcPase in GBM specifically serves in the clearance of macromolecular debris to facilitate ultrafiltration. In the GBM a laminar distribution is observed, suggesting that both epithelial and endothelial cells are involved in the production of AcPase. Accepted: 16 September 1997  相似文献   

7.
The acid phosphate activity (APA) associated with the isolated brush border membrane of the tapeworm, Hymenolepis diminuta, hydrolyzed p-nitrophenyl phosphate (PNPP), pyrophosphate (PPi), and beta-glycerophosphate (beta GP). Inhibition of PNPP hydrolysis at pH 4.0 was inhibited in a competitive manner by the following compounds (listed in order of decreasing affinity with their apparent inhibitor constants (Ki')): molybdate (0.031 mM); PPi (0.147 mM); NaF (0.150 mM); o-carboxyphenyl phosphate (0.261 mM); inorganic phosphate (0.770)); arsenate (3.45 mM); tartrate (22.1 mM); and beta GP (29.8 mM). Cu2+, formaldehyde, and arsenite at 10:1, 80:1, and 200:1 inhibitor to substrate ratios did not inhibit APA. The maximal rate of hydrolysis (Vmax) of each substrate was greater at pH 4.0 than 5.0. The apparent Michaelis constant (Km') for PNPP increased from 0.233 to 0.351 mM when the pH was raised from 4.0 to 5.0. The Km' for PPi decreased from 0.101 to 0.046 mM, while the Km' for beta GP changed from 2.04 to 2.22 mM under similar circumstances. APA and alkaline phosphatase activity increased as a function of temperature up to 45 degrees C.  相似文献   

8.
Summary A quantitative histochemical procedure was developed for the demonstration of purine nucleoside phosphorylase in rat liver using unfixed cryostat sections and the auxiliary enzyme xanthine oxidase. The optimum incubation medium contained 18% (w/v) poly(vinyl alcohol), 100 mM phosphate buffer, pH 8.0, 0.5 mm inosine, 0.47 mm methoxyphenazine methosulphate and 1 mm Tetranitro BT. An enzyme film consisting of xanthine oxidase was brought onto the object slides before the section was allowed to adhere. The specificity of the reaction was proven by the low amount of final reaction product generated when incubating in the absence of inosine. Moreover, 1 mm p-chloromercuribenzoic acid, a non-specific inhibitor of purine nucleoside phosphorylase, inhibited the specific reaction by 90%. The specific reaction defined as the test reaction, in the presence of substrate, minus the control reaction, in the absence of substrate was linear with incubation time at least up to 30 min as measured cytophotometrically. A high activity was observed in endothelial cells and Kupffer cells of rat liver and a lower activity in liver parenchymal cells. Pericentral hepatocytes showed an activity higher than that of periportal hepatocytes. In human liver, purine nucleoside phosphorylase activity was also high in endothelial cells and Kupffer cells, but the activity in liver parenchymal cells was only slightly lower than it was in non-parenchymal cells. The localization of the enzyme is in agreement with earlier ultrastructural findings using fixed liver tissue and the lead salt procedure.  相似文献   

9.
New lanthanide methods for the histochemical detection of non-specific alkaline phosphatase in the light microscope are described and compared with already existing techniques for the light microscopical demonstration of this enzyme. To avoid formation of insoluble lanthanide hydroxide at alkaline pH citrate complexes with the capture ions cerium, lanthanum and didymium were used. A molar ratio of 11 mM citrate/14 mM capture reagent is proposed. For preincubated sections, pretreatment in chloroform-acetone and fixation in glutaraldehyde, for non-preincubated sections fixation in glutaraldehyde yielded the best results. 4-Methylumbelliferyl and 5-Br-4-Cl-3-indoxyl phosphate were found to be the most suitable substrates. For routine purposes 4-nitrophenyl, 1-naphthyl, 2-naphthyl and 2-glycerophosphate were also sufficient; naphthol AS phosphates were inferior but still suitable. After incubation for 5-60 min at 37 degrees C lanthanide phosphate was converted into lead phosphate which was visualized as lead sulfide. At pH 9.2-9.5 enzyme activity was demonstrated at many sites such as intestinal, uterine, placental, renal and epididymal microvillous zones, plasma membranes of arterial, sinus and capillary endothelial cells, vaginal and urethral epithelium, smooth muscle cells, myoepithelial cells as well as excretory duct cells of salivary and lacrimal glands and in secretory granules of laryngeal glands. In comparison with Gomori's calcium, Mayahara's lead, Burstone's and Pearse's azo-coupling, McGadey's tetrazolium salt and Gossrau's azoindoxyl coupling technique the lanthanide methods detected alkaline phosphatase activities at identical or additional sites depending on the respective procedure.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

10.
The cellular and extracellular acid phosphatase (APase, Electrical Conductivity (EC) 3.1.3.2) activities in different Azolla spp. were induced in P-deprived condition after 48 h and maximum was on the 12th day of incubation. APase activity has been investigated at different levels of NaCl. Highest cellular and extracellular APase activities were observed in A. microphylla at 20 (2-fold of the control) and 30 mM (3.2-fold of the control) NaCl, respectively, while lowest were in A. filiculoides. Presence of different concentrations of micro- and macronutrients in saline medium regulated the APase activity of the Azolla. Ca2+ played a major role in enhancing the APase activity under salinity. Heavy metals did not affect APase activity at the lower level, whereas its higher level inhibited the activity. The enhancement in the APase activity under moderate salinity suggests the major contribution of APase activity during salt-responsive physiological adaptation of Azolla possibly by providing maximum inorganic phosphate to the association, which might be helpful in compensating for the energy crisis caused by salt-induced inhibition in photosynthetic machinery and also in regulating the nutrient imbalances during salt shock or process of adaptation towards heavily polluted agricultural land.  相似文献   

11.
The membrane-bound and solubilized (using Triton ×-100 or sodium dodecyl sulfate (SDS)) alkaline phosphohydrolase (APase) activities of the isolated brush border membrane of Hymenolepis diminuta require a divalent cation for maximum activity. Highest rates of substrate (p-nitrophenyl phosphate) hydrolysis are obtained with low concentrations of Mg2+ (1 mM), although low concentrations of Mn2+, Ca2+, or Zn2+ will also partially satisfy this requirement; higher concentrations of Mg2+ and Mn2+, and other divalent cations (Cu2+, Fe2+, and Pb2+), inhibit the membrane-bound APase activity. Solubilization of the membrane-bound enzyme in either Triton or SDS results in an increase in specific activity and Km, but has little effect on thermal stability of the APase activity. Phosphate, pyrophosphate, adenosine 5′-triphosphate, adenosine 5′-monophosphate, glucose 1-phosphate, glucose 6-phosphate, fructose 6-phosphate, and fructose 1,6-diphosphate inhibit substrate hydrolysis, and the relative affinities of these inhibitors for the APase enzyme are altered only slightly upon solubilization. Graphic analyses of data from inhibitor studies indicate that all eight inhibitors will inhibit membrane-bound and solubilized APase activities 100% at high inhibitonsubstrate ratios. Molybdate, F?, 2-mercaptoethanol, cysteine, and p-chloromercuribenzoate inhibit membrane-bound APase activity. Inhibitor data indicate that if more than one enzyme is responsible for the APase activity of the brush border membrane of H. diminuta, the enzymes cannot be differentiated on the basis of substrate specificity.  相似文献   

12.
Thermostable acid phosphatase (APase) from thermoacidophilic archaeon Sulfolobus acidocaldarius was isolated, partially purified, and characterized. The optimum pH and temperature of the enzyme for p-nitrophenylphosphate (pNPP) as a substrate were 5.0 and 70°C, respectively. The apparent K m value was 1.9 mM. This APase showed a native molecular mass of 20 kDa on a gel filtration chromatography. Of the APase activity, 60% remained after 60 min of heat treatment at 75°C. To confirm whether the APase is active in the monomeric form, we attempted to elute the enzyme from SDS-polyacrylamide gels with Disk electrophoresis apparatus and renature the enzyme. The APase activity was recovered up to 50% in the 14- to 35-kDa range, and maximum around 25 kDa. These results suggest that this APase is monomeric protein. Received: 8 July 1999 / Accepted: 9 August 1999  相似文献   

13.
Spectrophotometric and cytochemical methods were used to investigate the localization and/or the sensitivity of phosphatase activities in aldehyde-fixed beet leaves and membrane fractions. The nonspecific acid phosphatase substrates, p-nitrophenyl phosphate and beta-glycerol phosphate, each exhibited unique spectrophotometric patterns of hydrolysis as a function of pH. Additionally, beta-glycerol phosphatase activity was primarily present on the tonoplast, whereas p-nitrophenyl phosphatase was present on the plasma membrane. Because of the unique pH response of each enzyme and their different localization, we conclude that they cannot be entirely "nonspecific." The spectrophotometric pattern of ATP hydrolysis differed from that of p-nitrophenol phosphate in that it decreased at pH 5.0-5.5 and was greatly inhibited by 10 mM sodium fluoride; however, both activities were on the plasma membrane. Therefore, we conclude that these activities represent either two enzymes or only one enzyme that differs in its ability to hydrolyze these two substrates. Generally, enzymatically produced lead deposits on the plasma membrane of non-vascular cells were as frequent and large as those on phloem cells; frequently, deposits on sieve element plasma membranes were relatively small. We therefore conclude that there is no evidence for the presence of relatively intense ATPase activity on the plasma membrane of phloem cells in beet leaf, in contrast to other species. Studies with membrane fractions indicated that formaldehyde could completely inhibit the inhibitor-sensitive phosphatase activities in mitochondrial and vacuolar fractions while preserving significant activity in the plasma membrane fraction.  相似文献   

14.
运用CF输导方法确定正在进行库源转换的叶片。采用铅沉淀法对蚕豆(Vicia faba)幼嫩叶片、库源转换叶的库区和源区的小叶脉组织细胞进行了ATP酶和酸性磷酸酶的细胞化学定位。结果显示, 在蚕豆幼嫩叶片的小叶脉中, 传递细胞质膜和细胞壁上存在大量的ATP酶和酸性磷酸酶的标记产物。在库源转换叶库区传递细胞和筛分子质膜上ATP酶和酸性磷酸酶的标记较弱。在库源转换叶的源区传递细胞和筛分子质膜存在较强的ATP酶和酸性磷酸酶的活性反应产物。在小叶脉分化中的木质部分子存在较强的ATP酶和酸性磷酸酶的活性标记, 在分化成熟的木质部分子酶的标记显著减弱。实验结果表明, 依据不同的发育阶段, ATP酶和酸性磷酸酶的含量在蚕豆小叶脉的不同细胞中呈动态变化。据此, 对ATP酶和酸性磷酸酶在蚕豆小叶脉细胞分化和质外体装载中的作用进行了讨论。  相似文献   

15.
In this study, the effects of phosphate concentration and carbon source on the patterns of alkaline phosphatase (APase) and phospholipase (PLase) expression in Vibrio vulnificus ATCC 29307 were assessed under various conditions. The activities of these enzymes were repressed by excess phosphate (4 mM) in the culture medium, but this repression was reversed upon the onset of phosphate starvation in low phosphate defined medium (LPDM) containing 0.2 mM of phosphate at approximately the end of the exponential growth phase. The expressions of the two enzymes were also influenced by different carbon sources, including glucose, fructose, maltose, glycerol, and sodium acetate at different levels. The APase activity was derepressed most profoundly in LPDM containing fructose as a sole carbon source. However, the repression/derepression of the enzyme by phosphate was not observed in media containing glycerol or sodium acetate. In LPDM-glycerol or sodium acetate, the growth rate was quite low. The highest levels of PLase activity were detected in LPDMsodium acetate, followed by LPDM-fructose. PLase was not fully repressed by high phosphate concentrations when sodium acetate was utilized as the sole carbon source. These results showed that multiple regulatory systems, including the phosphate regulon, may perform a function in the expression of both or either APase and PLC, in the broader context of the survival of V. vulnificus.  相似文献   

16.
The localization of guanylate cyclase activity was cytochemically studied in heart tissue from guinea pig and pigeon. The method, based on a lead precipitation technique with GPPNHP as the substrate, was tested by quantitative biochemical analysis. The data obtained showed that in heart homogenates GPPNHP is an acceptable substrate for guanylate cyclase. The guanylate cyclase activity of glutaraldehyde prefixed heart tissue was also measured in the presence of 2 mM lead nitrate, in 30% of the untreated control hearts. The residual guanylate cyclase responded to the addition of sodium nitroprusside with a 7-fold increase in its activity. Furthermore, the guanylate cyclase requirement for Mn2+ ions was so changed by this activator that Mg2+ was as active as Mn2+. In heart muscle cells of guinea pigs and pigeons the plasma membrane of the sarcolemma and the junctional sarcoplasmic reticulum are the precipitation sites of the reaction product. In guinea pig hearts the T-tubule membranes were likewise covered with precipitates. Sodium nitroprusside stimulation of guanylate cyclase activity was indicated by increased precipitation and by shortening of the incubation time.  相似文献   

17.
A cytochemical method allowing the localization and quantification of plasma membrane Ca2+-ATPase (PMCA) in frozen sections obtained from digestive gland cells of Mytilus galloprovincialis, Tapes tapes and Chamelea gallina, is presented. The method utilizes lead as a trapping agent of PO4(2-) ions released by Ca2+-ATPase activity. The amount of lead sulphide precipitate proportionally related to PMCA activity was quantified by a light microscopy digital imaging analysis system. The optimal assay conditions of Ca2+-ATPase activity evaluated at pH 7.4 were: 200 microM free Ca2+, 200 mM KCl, 2 mM ATP, and under such analysis conditions the enzyme showed a linear trend up to 60 min (at 20 degrees C). The PMCA activity was substrate specific: ADP was utilized only at a low rate (24% with respect to an equimolar ATP concentration), while glucose-6-phosphate and beta-glycerophosphate were poorly hydrolyzed. The enzyme activity was strongly inhibited by sodium ortho-vanadate. Our detection of a Ca2-ATPase activity at nanomolar concentrations of free Ca2+ suggests that we have identified a plasma membrane Ca2-ATPase involved in Ca2+ homeostasis. The Ca2+-ATPase was found to be localized in the basal part of the plasma membrane in the digestive gland cells of Mytilus galloprovincialis and Tapes tapes, but in the apical plasma membrane of Chamelea gallina. The possible implications of the different cellular distributions of PMCA activity is discussed.  相似文献   

18.
The localization of alkaline phosphatases in dentinogenically active rat incisor odontoblasts was studied by means of subcellular fractionation and electron microscopical histochemistry. Subcellular fractionation revealed the predominant phosphatase activity to be present in the microsome fraction and to a lesser extent in the mitochondrial fraction. Adenosine triphosphate degrading enzyme activity was determined in the presence or absence of (+/-)-6(m-bromophenyl)-5, 6-dihydroimidazo(le) (2,1-b) thiazole oxalate (R 8231). Before the histochemical study, the effects on phosphatase activities by aldehyde fixation were studied by biochemical assay. A method of fixation for optimal preservation of phosphatase activity is presented. Phosphatase electron microscopic histochemistry was performed by using ATP as a substrate and with or without addition of the inhibitor R 82319 Precipitates were seen in the membranes of vesicles present in the odontoblast process and the Golgi region. When there were signs of insufficient fixation, precipitates were also seen in the outer membranes of mitochondria. No phosphatase activity was seen in the cell membrane. ATP degrading enzyme activities mediated by nonspecific alkaline phosphatase (APase) and Ca2+ -adenosine triphosphatase thus have the same morphological localization. This close association is consistent with earlier biochemical studies.  相似文献   

19.
This study was undertaken to localize the enzyme sodium-potassium dependent adenosine triphosphatase in unstimulated human small lymphocytes using the histochemical technique of McClurkin [1964]. The substrate adenosine 5' triphosphate is hydrolyzed by the ATPase resulting in a lead phosphate precipitate at the site of enzyme action, subsequently visualized as lead sulphide. The enzyme was demonstrated in three different patterns, and for each donor the pattern was constant both on all four of the test slides, and on different occasions. The patterns observed were: clusters of granules related to the cell membrane; positive staining localized to portions of the cell membrane, and, less commonly, the whole cell circumference. The significance of this distribution may relate to areas with large numbers of antigen recognition sites on the lymphocyte membrane.  相似文献   

20.
Diclofenac sodium is known to interfere with renal physiology by inhibiting prostaglandins. Previous studies indicate that various nephrotoxins damage proximal renal tubules by altering alkaline phosphatase (APase) activity. APase has been reported to be a function related marker in renal proximal tubular epithelia where it is highly expressed. Present investigation deals with toxicity caused in mice kidney at histological and biochemical levels after diclofenac administration. Diclofenac toxicity was assessed by localizing APase in kidney histochemically and biochemically. Intramuscular diclofenac administration (10 mg/kg/body wt) for 30 days exhibited substantial degeneration in kidney. A marked change in APase activity was observed in histochemical and biochemical studies. A change was noticed in specific activity of APase at different periods of diclofenac treatment. Decrease in specific activity of APase after 10 days (18.41 %) and 30 days (55.3 %) of diclofenac exposure was observed. However, an insignificant hike in APase was observed after 20 days of drug therapy. Similar trends in APase activity were evidenced by the electrophoretic analysis. Histological and ultrastructural observations also corroborated above mentioned findings. Present investigation gives an insight into probable mechanism of renal pathology caused by diclofenac administration in mice.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号