Comparison of several enzymes between normal physeal and tibial dyschondroplastic cartilage of broiler chickens

Normal physeal and dyschondroplastic cartilage of broiler chickens was examined for six enzymes by isoelectric focusing in thin-layer polyacrylamide slab gels. Acid phosphatase (ACP), esterase (EST), malate dehydrogenase (MDH), and peroxidase (PRX) were present in the normal physeal cartilage but not in the dyschondroplastic cartilage. Staining intensity of glucose-6-phosphate isomerase (GPI) and triose-phosphate isomerase (TPI) was reduced in the dyschondroplastic cartilage compared with that of the physeal cartilage. Differences in the presence of these enzymes possibly demonstrated their roles in processes of bone formation, cartilage resorption, and calcification. ACP could be involved in calcification. Lack of EST and PRX may be related to the failure of vascular invasion in dyschondroplastic cartilage of afflicted birds. A deficiency of MDH and reduced GPI and TPI in dyschondroplastic cartilage may reflect a reduction in the activity of energetic metabolism, causing the dissipation of energy and necrotic cells.

Differences in isoenzyme patterns of axenically and monoxenically grown Acanthamoeba and Hartmannella

Axenically and monoxenically grown Acanthamoeba castellanii, Acanthamoeba polyphaga and different isolates of Hartmannella vermiformis strains were examined by polyacrylamide isoelectric focusing in the pH range 3-10. Isoenzyme patterns of acid phosphatase (AP), propionyl esterase (PE), malate dehydrogenase (MDH), alcohol dehydrogenase (ADH), glucose phosphate isomerase (GPI) and phosphoglucomutase (PGM) were compared. Zymograms were used to reveal differences in typical isoenzyme patterns between axenically and monoxenically grown amoebae and to compare axenically grown A. castellanii, A. polyphaga and H. vermiformis. Comparison of zymograms for AP, PE and MDH between axenically grown Acanthamoeba and Hartmannella strains revealed different isoenzyme patterns. Acanthamoeba showed strong bands for ADH and extremely weak bands for GPI and PGM, while Hartmannella lacked ADH but possessed bands for GPI and PGM. Comparison of zymograms from axenically and monoxenically grown amoebae revealed a lower intensity and even lack of typical isoenzyme bands in lysates from monoxenic cultures. The observed changes in typical isoenzyme patterns induced by the bacterial substrate can influence the correct isoenzymatic typing of different strains in clinical and phylogenetic studies.

First isolation and characterization in humans of Entamoeba histolytica (laboratory-made) zymodeme XX

Isoenzyme analysis by starch-gel electrophoresis has proved to be a useful method for the biochemical differentiation of pathogenic Entamoeba histolytica and non-pathogenic E. dispar isolates. Of the known 24 zymodemes, 3 are laboratory-made and have not previously been identified in humans. Parasitology screening was carried out in a psychiatric institution. Two amebic stocks were isolated and characterized that had never previously been found in humans and that have protein patterns identical to that of the laboratory-made zymodeme XX.

Isoenzymes of Eimeria from the domestic fowl: electrophoretic variants among species, strains and clones

Electrophoretic variation of enzymes in five Eimeria spp. of the domestic fowl, including nine strains, ten single-sporocyst clones and two single-sporozoite clones of E. acervulina, three strains each of E. maxima and E. tenella, two strains of E. praecox and one strain of E. necatrix, were assayed using cellulose acetate electrophoresis. Ten enzymes [aldehyde oxidase (AO), alkaline phosphatase (ALP), amylase (AMY), fumarate hydratase (FUM), glucose-6-phosphate dehydrogenase (G6PDH), glucose phosphate isomerase (GPI), glutamate-oxaloacetate transferase (GOT), isocitrate dehydrogenase (IDH), malate dehydrogenase (MDH) and phosphoglucomutase (PGM)] were analyzed for their ability to distinguish between these species and strains. Enzymatic activity of G6PDH, GPI, IDH, MDH and PGM was detected in all the Eimeria spp. examined. Strains within each species were characterized by the same electrophoretic variant of G6PDH. Electrophoretic variants of GPI and PGM were the most valuable in the identification of inter- and intra-specific variation, particularly in the field strains of E. acervulina and E. tenella. These two enzymes were used to examine single-sporocyst and single-sporozoite clones derived from two strains of E. acervulina. The enzymes in E. maxima appeared to be conserved, showing no variation among strains with the five enzymes detected. Relative mobilities, calculated as described in this paper, were found to be consistent between different electrophoresis runs and may serve as a reference when this medium is used.

Seasonal variations in the temperature acclimation response of the channel catfish, Ictalurus punctatus

Channel catfish were collected on 11 different dates from October 1991 to July 1993 and acclimated in the laboratory to 7 degrees C, 15 degrees C, or 25 degrees C for 6 wk. Hepatosomatic index, mg protein mg-1 DNA, total liver DNA and protein, and the activities of liver glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, lactate dehydrogenase, and malate dehydrogenase were measured to examine seasonal variation in the acclimation response. Liver and muscle cytochrome oxidase and lactate dehydrogenase activities were measured to compare tissue-specific responses. Hepatosomatic indexes of fall and winter channel catfish were highest at 7 degrees C, with values at 15 degrees C higher than at 25 degrees C, while spring and summer fish had the highest values at 15 degrees C, with values at 7 degrees C higher than those at 25 degrees C. Acclimation patterns for total liver protein and DNA, mg protein mg-1 DNA, and glycogen were generally higher in cold temperatures but varied seasonally in an unpredictable manner. Glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and malate dehydrogenase demonstrated positive acclimation in the fall and winter; fish collected in the spring and summer showed little or inverse acclimation. Liver lactate dehydrogenase activity showed little or no positive compensation at any time of the year. Cytochrome oxidase activity showed positive acclimation in muscle but not liver. All liver enzymes, even those that showed marginal acclimation on a protein basis, showed positive acclimation when activity was expressed on a whole-liver basis.

Iron-ascorbate cleavable malic enzyme from hydrogenosomes of Trichomonas vaginalis: purification and characterization

Two isoforms of NAD(P)(+)-dependent malic enzyme (EC 1.1.1.39) were isolated from hydrogenosomes of Trichomonas vaginalis. A positively charged isoform at pH 7 was obtained in a single purification step using cation-exchange chromatography. The second isoform, negatively charged at pH 7.5, was partially purified using a combination of anion-exchange and affinity chromatography. Both isoforms displayed similar physical and kinetic properties. Molecular weight determination of the native enzyme suggested a homotetrameric arrangement of the 60 kDa subunits. The enzyme utilized NAD+ (Km, 6-6.3 microM) preferentially to NADP+ (Km, 125-145 microM). The NAD(+)-dependent activity showed a broad pH optimum with maximum under alkaline conditions (pH 9) likely to be present inside hydrogenosomes. Immunocytochemical studies using a polyclonal rabbit antibody raised against purified T. vaginalis malic enzyme proved hydrogenosomal localization of the enzyme. Subfractionation of hydrogenosomes suggested an association of the malic enzyme with the hydrogenosomal membranes. The 60 kDa malic enzyme subunit was highly sensitive to non-enzymatic cleavage by an iron-ascorbate system resulting in two enzymatically inactive fragments of about 31 kDa. Microsequencing of the fragments revealed that the 60 kDa subunit was cleaved at the metal-binding site between Asp279-Ile280. The enzyme inactivation was inhibited by an excess of manganese. Iron-dependent posttranslational modification might contribute to the regulation of malic enzyme activity in vivo.

Characterization of Trichuris skrjabini by isoenzyme gel electrophoresis: comparative study with Trichuris ovis

Morphological and biometric studies were performed in Trichuris skrjabini (Baskakov, 1924) collected from the caecum of Capra hircus. The LDH (EC 1.1.1.27.), G6PD (EC 1.1.1.49.), GPI (EC 5.3.1.9.), MDH (EC 1.1.1.37) and malic enzyme (ME) (EC 1.1.1.40) isoenzymatic patterns of T. skrjabini were determined by starch gel electrophoresis. The G6PD and GPI isoenzymatic patterns of T. skrjabini displayed two anodic bands for both enzymes: one fast migration band and one band near the origin. This isoenzymatic pattern was interpreted as two gene loci encoding both enzymes. The LDH isoenzymatic pattern of T. skrjabini was characterized by the presence of a cathodically migrating band, while the MDH isoenzymatic pattern showed a very slow cathodic band. These two phenotypes were interpreted as the expression of a homozygous state of a gene locus for LDH and MDH in T. skrjabini. The ME isoenzymatic pattern was characterized by the presence of a single anodic band. Further, comparative isoenzymatic studies were carried out between T. skrjabini and T. ovis. The different G6PD, GPI, LDH, MDH and ME isoenzymatic patterns observed for both species allowed us to distinguish them and therefore to use isoenzymatic patterns as a diagnostic tool to differentiate species of Trichuris.

[Effects of low-intensity electromagnetic radiation of extremely high frequency on the animal body within the framework of total low-dose x-ray irradiation]

Effect of low-intensive electromagnetic radiation of extremely high frequency (EMR EHF) on the rats, subjected to the low-dose X-ray irradiation (6.192 mC/rg) was investigated. Content of glial fibrillary acidic protein as well as glucose content and activity of glutamate dehydrogenase and malate dehydrogenase was studied. It was shown than EMR EHF modifies the X-ray irradiation effect: filament GFAP concentration in brain and glucose content in serum were restored. The authors suggest central nervous system participation in realization of EMR EHF effects on the organism.

Tritrichomonas foetus: isolation and characterization of the Golgi complex

An effective methodology to isolate and characterize the Golgi complex of Tritrichomonas foetus is described in this work. Using sucrose density gradient centrifugation, two highly enriched Golgi fractions (GF1 and GF2) were obtained. Enzymatic assays of GF1 and GF2 showed a strong enrichment in galactosyltransferase activity (20- and 7-fold, respectively), with minimal contamination with other organelles. The GF fraction was further subfractionated by alkaline treatment, which resulted in the production of Golgi content and membrane subfractions. Electron microscopic observations of intact cells or Golgi fractions fixed in solutions containing glutaraldehyde and tannic acid, as well as of deep-etched replicas of isolated fractions, revealed the presence of discrete bridges only between closely apposed cisternae.

Studies on associations of glycolytic and glutaminolytic enzymes in MCF-7 cells: role of P36

Isoelectric focusing of MCF-7 cell extracts revealed an association of the glycolytic enzymes glyceraldehyde 3-phosphate-dehydrogenase, phosphoglycerate kinase, enolase, and pyruvate kinase. This complex between the glycolytic enzymes is sensitive to RNase. p36 could not be detected within this association of glycolytic enzymes; however an association of p36 with a specific form of malate dehydrogenase was found. In MCF-7 cells three forms of malate dehydrogenase can be detected by isoelectric focusing: the mitochondrial form with an isoelectric point between 8.9 and 9.5, the cytosolic form with pl 5.0, and a p36-associated form with pl 7.8. The mitochondrial form comprises the mature mitochondrial isoenzyme (pl 9.5) and its precursor form (pl 8.9). Refocusing of the pl 7.8 form of malate dehydrogenase also gave rise to the mitochondrial isoenzyme. Thus, the pl 7.8 form of malate dehydrogenase is actually the mitochondrial isoenzyme retained in the cytosol by the association with p36. Addition of fructose 1,6-bisphosphate to the initial focusing column induced a quantitative shift of the pl 7.8 form of malate dehydrogenase to the mitochondrial forms (pl 8.9 and 9.5). In MCF-7 cells p36 is not phosphorylated in tyrosine. Kinetic measurements revealed that the pl 7.8 form of malate dehydrogenase has the lowest affinity for NADH. Compared to both mitochondrial forms the cytosolic isoenzyme has a high capacity when measured in the NAD --> NADH direction (malate --> oxaloacetate direction). The association of p36 with the mitochondrial isoenzyme may favor the flow of hydrogen from the cytosol into the mitochondria. Inhibition of cell proliferation by AMP which leads to an inhibition of glycolysis has no effect on complex formation by glycolytic and glutaminolytic enzymes in MCF-7 cells. AMP treatment leads to an activation of malate dehydrogenase, which correlates with the increase of pyruvate and the decrease of lactate levels, but has no effect on the distribution of the various malate dehydrogenase forms.

Biomimetic-dye affinity chromatography for the purification of mitochondrial L-malate dehydrogenase from bovine heart

Seven biomimetic anthraquinone triazinyl dye-ligands, bearing as triazine-linked terminal moiety (keto)carboxylated structures mimicking substrates and inhibitors of malate dehydrogenase (MDH), were immobilised on cross-linked agarose Ultrogel A6R. These biomimetic ligands are terminal-ring analogues of commercial nonbiomimetic Cibacron blue 3GA (CB3GA) and parent Vilmafix blue A-R (VBAR). The biomimetic-dye adsorbents, along with nonbiomimetic adsorbents bearing immobilised CB3GA and VBAR, were evaluated for their ability to purify mitochondrial malate dehydrogenase (mMDH) from bovine heart. All but two biomimetic-dye adsorbents displayed higher purifying ability for MDH, compared to nonbiomimetic-dye adsorbents. Furthermore, immobilised anthraquinone-dyes were able to discriminate between the mitochondrial and the cytoplasmic MDH isoenzymes, binding only to the former. One immobilised biomimetic-dye (BM5), bearing as biomimetic terminal moiety 4-aminophenyloxanylic acid, showed the highest purifying ability. This affinity adsorbent was exploited in the purification of mMDH from unpretreated bovine heart extract in one-step. The procedure afforded mMDH at 54% overall yield and of specific activity approx. 1300 U mg-1 (25 degrees C), using step-elution with a mixture containing 0.1 mM beta-nicotinamide adenine dinucleotide (NAD+) and 1.5 mM sulphite. Commercial analytical-grade bovine heart mitochondrial MDH, when assayed under identical conditions, gave a specific activity not exceeding 950 U mg-1. The well-known adsorbent Cibacron blue 3GA-agarose exhibited 8% lower recovery and 25% lower purification for mMDH. The product obtained from the procedure based on the BM5-adsorbent was free of cytoplasmic MDH, glutamic-oxaloacetic transaminase (GOT) and fumarase, and since it has also shown high specific activity, it should be suitable for analytical applications.

[Localization and characteristics of lactate and malate dehydrogenase in the sparganum and adult worm of Spirometra erinacei]

This study investigated the enzyme histochemical localization and characteristics of lactate (LDH) and malate dehydrogenase (MDH) related with the oxidation-reduction metabolism in the sparganum and adult of S. erinacei. By enzyme histochemical assay, activity of LDH was strong in the tegument and subtegumental muscle layers of the adult and sparganum. Activity of MDH was strong in the tegument of the sparganum and subtegumental muscle layers of the adult. However it was weak in the tegument of the adult. By electrophoresis, 45 kDa band was major and common in LDH of adults and spargana. The 150 kDa molecule was the major and common band in MDH of adults and r-spargana (from experimentally infected rats). By isoelectrofocusing, isoelectric points (PI) of 4 MDH isozyme from adult worm were 6.0, 6.5, 6.7 and 7.1, respectively. PI 6.0 was the major band. The active range of pH for MDH was about pH 6 approximately 8 and the optimum pH was pH 7. The effective temperature on the MDH was about 30 degrees C approximately 50 degrees C and the optimum temperature was about 40 degrees C in spargana and adult worm. In the stability against heat, when MDH was heated at 85 degrees C for 10 seconds, the activity was denatured perfectly. Maximum activity of MDH was 19.4 unit in the s-sparganum (from snakes), 24.5 unit in the r-sparganum (from rats) and 108.0 unit in the adult worm. The maximum activity was higher in adults than in spargana. The present result showed us that the nutrients absorbed through the tegument were transferred into inner tissues and were utilized as the source of metabolism. According to the habitat of the parasite, the isozymes of LDH and MDH are activated differently, and by this different activation the sparganum and adult can adapt themselves to parasitic circumstances.

A novel automated assay for malate dehydrogenase isoenzymes

We have developed a new automated method for the determination of malate dehydrogenase (MDH) isoenzymes in serum employing guanidine hydrochloride. Our proposed method showed good reproducibility; within-run precision coefficient of variations (CVs) were less than 2.5 (mean 13.6-42.9 U/L) for total MDH (T-MDH) and less than 6.7% (mean 6.3-23.5 U/L) for mitochondrial MDH (m-MDH) (n = 10). The upper detection limit of the proposed method exhibited good linearity up to 1,000 U/L for both T-MDH and m-MDH. In the proposed m-MDH reagent, the presence of up to 2,000 U/L of cytosolic MDH(c-MDH) activity had no effect on the outcome of m-MDH assay. Results of our proposed method (y) correlated well with those of the electrophoretic method (x) giving the regression equation: y = 1.46 x + 6.87 (N = 30); r = 0.99. Normal concentrations of various anticoagulants and bilirubin did not affect the assay results. Both ascorbic acid and glucose exhibited a slight positive interference with the proposed assay. Clinically, we found that m-MDH activity in serum had greater diagnostic predictive value than T-MDH activity for judging successful outcome of reperfusion therapy; the prognosis was poor when the m-MDH/T-MDH ratio was greater than 20%.

Malic dehydrogenase isoenzymatic pattern in lung-nematode parasite species

The malic dehydrogenase (MDH) isoenzymatic pattern of Dictyocaulus viviparus, Protostrongylus rufescens, and Slovakian and Spanish isolates of D. filaria was studied. The MDH isoenzymatic pattern in both isolates of D. filaria was characterized by the presence of three phenotypes: (1) a single, slow anodic band; (2) a single, fast anodic band; and (3) a large spot matching its migration with bands 1 and 2. These three phenotypes may be explained as the existence of only one gene locus for the MDH in D. filaria. Allelic frequencies and the Hardy-Weinberg test were determined for Slovakian and Spanish isolates of D. filaria. This test indicated that the population was not in Hardy-Weinberg equilibrium. The MDH isoenzymatic pattern of D. viviparus displayed the same phenotypes 1 and 2 observed in D. filaria. Furthermore, the MDH isoenzymatic pattern of P. rufescens was characterized by the presence of two bands with anodic and cathodic migration. The isoenzyme with anodic migration appeared more intensively stained than did that with cathodic migration. This last isoenzyme was not observed when the samples had been stored for 1 month.

Morphometric and metabolic profile of the distal segment of the internal mammary artery: caution on its use for coronary anastomoses

OBJECTIVE

Elastic arteries were found to be less prone to intimal hyperplasia than muscular arteries. The internal mammary artery (IMA), which is elastic in its proximal segment, presents a gradual decrease of media elastic fibers along its downstream course. Metabolic and morphometric studies of the distal end of the IMA with regard to its local susceptibility to develop intimal changes were undertaken in order to evaluate the reliability of its use as an anastomotic site for bypass grafting.

METHODS

Twenty distal segments of IMA were harvested from patients who had undergone myocardial revascularization. Histologic, enzyme-histochemical and morphometric studies were undertaken on these arterial segments.

RESULTS

Histologic examinations indicated an elastomuscular structure in 13 patients, a muscular structure in 6 and an elastic structure in 1. Of the 20 IMAs, none was found to have intimal thickening of greater than 25% of the diameter of the lumen. The enzyme-histochemical profile of the proliferating cells found in the intimal thickening differed from normal contractile smooth muscle medial cells in the loss of myosin and mitochondrial ATPase, plasma membrane 5' nucleotidase, moderately decreased aerobic dehydrogenase and increased lactate dehydrogenase activity and ribonucleoprotein-linked pyroninophilia. Lysosomal beta-glucuronidase and sulfatase were strongly active. This enzyme behavior is unfavorable to contractile function and favorable to cell proliferation and lipid accumulation, two events strongly involved in the atherogenic process.

CONCLUSION

Intimal proliferative changes were observed in the distal segment of the IMA. Although there was no histologic evidence of atherosclerotic plaque, the enzyme-histochemical profile of this intimal thickening was favorable to cell proliferation and lipid accumulation. These findings suggest that it may be beneficial to avoid coronary anastomoses with the distal end of the IMA and to use a more proximal/elastic segment.

Amino acid concentrations and selected enzyme activities in rat auditory, olfactory, and visual systems

Homogenates of specific brain regions of three sensory systems (auditory, olfactory, and visual) were prepared from pigmented Long-Evans Hooded rats and assayed for amino acid concentrations and activities of glutaminase, aspartate aminotransferase (total, cytosolic, and by difference, mitochondrial), malate dehydrogenase, lactate dehydrogenase, and choline acetyltransferase. Comparing the quantitative distributions among regions revealed significant correlations between AAT and aspartate, between glutaminase and glutamate, between glutamate and glutamine, and between AAT plus glutaminase, or glutaminase alone, and the sum of aspartate, glutamate, and GABA, suggesting a metabolic pathway involving the synthesis of a glutamate pool as precursor to aspartate and GABA. Of the inhibitory transmitter amino acids, GABA concentrations routinely exceeded those of glycine, but glycine concentrations were relatively high in brainstem auditory structures.

Determinants of hydroperoxide detoxification in diabetic rat intestine: effect of insulin and fasting on the glutathione redox cycle

The capacity for hydroperoxide detoxification in diabetic (DM) intestine was studied in streptozocin-induced DM rats by quantification of the intestinal glutathione (GSH) redox cycle, a key cellular pathway for peroxide elimination. A role for luminal glucose in regulation of redox cycle activity was examined in insulin-treated or 24-hour-fasted DM animals. Intestinal activities of the redox enzymes, GSH peroxidase, GSSG reductase, and glucose-6-phosphate dehydrogenase (G6PD), were significantly decreased by 17 hours' insulin treatment, whereas only G6PD was decreased by fasting. Mucosal GSH levels were also markedly decreased under these conditions. These results are consistent with an overall suppression of intestinal GSH redox cycle function by short-term administration of insulin. Insulin treatment for 7 consecutive days increased hepatic G6PD activity by fourfold but was without effect on intestinal G6PD, suggesting tissue specificity in insulin regulation of G6PD. The rate of metabolism of tert-butyl hydroperoxide (tBH) in isolated enterocytes was low in the absence of substrates (0.51 +/- 0.07 nmol/10(6) cells/min) but was increased fivefold by exogenous glucose (2.70 +/- 0.11 nmol/10(6) cells/min), indicating that glucose availability is an important contributor to intestinal detoxification of toxic hydroperoxides. Collectively, the current results show that GSH redox cycle enzymes in DM intestine are under coordinate insulin control, and that this control appears to be downregulated by short-term insulin treatment.

Polyunsaturated fatty acid-mediated suppression of insulin-dependent gene expression of lipogenic enzymes in rat liver

The effects of dietary polyunsaturated fat on insulin-dependent gene expression of lipogenic enzymes and a possible mechanism for PUFA-mediated suppression of the gene expression have been investigated in rat livers. When diabetic rats were injected with insulin, the insulin dose-dependent induction of lipogenic enzyme mRNAs were markedly reduced with increasing dietary corn oil. On the other hand, the PUFA-mediated suppression of the mRNA concentrations was partially restored by treatment with pioglitazone, a candidate for increasing insulin receptor phosphorylation. Moreover, insulin binding to receptors of liver, receptor autophosphorylation, and kinase activity toward exogenous substrate were lower in the corn oil diet group than in the hydrogenated fat group. The PUFA-mediated suppression of insulin binding was somewhat restored by pioglitazone, and the suppression of insulin receptor phosphorylation was significantly restored. It is suggested that the PUFA-mediated suppression of insulin-dependent gene expression of lipogenic enzymes can be ascribed to a decrease in insulin receptor binding primarily and also to receptor phosphorylation. Thus, PUFA appears to suppress the lipogenic enzyme gene expression stimulated by insulin.

Biochemical characterisation of human isolates of Blastocystis hominis

SDS-PAGE and iso-enzyme analysis of 11 human isolates of Blastocystis hominis revealed at least two variants with different polypeptide patterns and two zymodemes, respectively. This is the first iso-enzyme and the second protein analysis to indicate strain differences in B. hominis.

Comparative studies on NADP(+)-linked malic enzyme in the central nervous system of ectothermic and endothermic animals

The maximum activity and intracellular distribution of NADP(+)-linked malic enzyme in brain of Mammalia, Aves, Reptilia, Amphibia and Pisces are reported. Malic enzyme activity was present in all animals brains investigated. Most of the enzyme activity was located in the mitochondrial fraction. In brain of endothermic animals the activity of malic enzyme was several-fold higher than in ectothermic animals. Other NADPH-producing enzymes (i.e. NADP(+)-linked isocitrate dehydrogenase and hexosemonophosphate shunt dehydrogenase) activities were essentially similar in all animals brains tested. However, the total potential capability of NADPH production was lower in ectothermic animals (due mainly to lower malic enzyme activity). It is suggested that the presence of NADP(+)-linked malic enzyme in the brain may be related mainly to mitochondrial metabolism, especially to maintain the mitochondrial pool of NADP+ in reduced form.

Electrophoretic conditions for high resolution citrus isozymes in polyacrylamide gel electrophoresis

Electrophoretic conditions including electrode and gel buffers, acrylamide concentration, use of stacking gels, voltage, current, and run time were investigated in order to produce isozyme bands of high resolution which would facilitate densitometric quantification of enzyme activity following polyacrylamide gel electrophoresis (PAGE). Electrode buffers which provided optimal conditions for gels stained for the isozymes of malate dehydrogenase (MDH), 6-phosphogluconate dehydrogenase (6-PGD), phosphoglucose isomerase (PGI), and shikimate dehydrogenase (SkDH) were 0.02 M Tris-glycine, pH 8.5, 0.1 M sodium borate, pH 6.0, 0.1 M sodium borate, pH 8.7, and 0.07 M sodium borate, pH 7.0, respectively. A 0.5 M Tris-HCl, pH 7.5, gel buffer was optimal for gels stained for the isozymes of 6-PGD, PGI and SkDH. A 0.5 M Tris-HCl, pH 8.5, gel buffer was best for gels stained for MDH. Stacking gels were found to be detrimental to enzyme activity and showed no improvement in resolution for any of the enzymes. Acrylamide concentration for gels stained for MDH were 8.7%, gels stained for 6-PGD and PGI were 7.5%, while gels stained for SkDH had an acrylamide concentration of 5.0%. Higher concentrations above these levels caused a reduction and in some cases loss of band activity, while below this concentration there was a decrease in band resolution.(ABSTRACT TRUNCATED AT 250 WORDS)

Sarcocystis fusiformis: some Krebs cycle enzymes in various fractions of sarcocysts of buffalo (Bubalus bubalis)

A biochemical investigation was carried out on the relative presence of some enzymes of the Krebs cycle and of the associated energy metabolism in various fractions (namely, cyst wall, cyst fluid and zoites) of sarcocysts of Sarcocystis fusiformis from the oesophageal muscles of naturally infected Indian water buffalo (Bubalus bubalis). Except for malate dehydrogenase, the activities of aconitase, isocitrate dehydrogenase, succinate dehydrogenase and fumarase were beyond detectable limits, pointing to a non-functional Krebs cycle in the cysts of this parasite. The activities of adenosine triphosphatase and cytochromes were lowest in cyst fluid and were maximally depicted by cyst wall and zoites.

Species identification of cyst and root-knot nematodes from potato by electrophoresis of individual females

To carry out rapid and reliable species identification of Globodera and Meloidogyne specimens, two electrophoretic methods were modified and adapted for an automated electrophoresis system (PhastSystem, Pharmacia). Proteins of individual Globodera cysts were identified using isoelectric focusing and a sensitive silver stain. Proteins of young single Meloidogyne females were separated using polyacrylamide gradient gels and stained for the isozymes esterase and malate dehydrogenase.

Entamoeba histolytica autochthonous isolates from mentally retarded Italian patients

A total of 77 mentally retarded male inpatients residing in a psychiatric institution in northern Italy were screened for the presence of stool parasites, Entamoeba histolytica particularly. Parasitological stool examination showed Entamoeba spp. (E. histolytica and/or E. dispar) in 26 cases (33.7%). In vitro culture on Robinson's medium was positive in 16 cases (61.1%); in 11 cases we could stabilize and clone the isolates and proceed to electrophoretic assays. In all cases, patterns of pathogenic zymodemes were found (zymodeme II, 3 isolates; zymodeme XII, 4 isolates; zymodeme XIV, 4 isolates). All isolates were therefore identified as E. histolytica.

Selectivity in electrophoretically mediated microanalysis by control of product detection time

Differential electrophoretic mobility between an analyte and its product offers electrophoretically mediated microanalysis (EMMA) a unique capability to selectively control the detection time of the product of a reaction-based chemical analysis. If an analyte and its product differ in migration velocity under the influence of an applied electric field, the apparent velocity and, consequently, the detection time of the product are dependent upon the relative amounts of time the product effectively traverses the capillary with the respective mobilities of the analyte and the product. Consequently, by controlling when the analytical reaction is allowed to occur, the detection time of the reaction product can be selectively maneuvered within a time window defined by the mobilities of the analyte and the product. This paper describes the use of this technique to manipulate the detection time of product profiles independently of nonreacting matrix interferants for the determination of both enzymes and substrates by EMMA. Furthermore, the ability to manipulate product detection times allows for simultaneous EMMA determinations of multiple enzymes or substrates.