Purification and properties of Arthrobacter neuraminidase

Neuraminidase (EC 3.2.1.18) from an Arthrobacter species was purified homogeneity by conventional procedures (yield approx. 1 mg/1) and was judged to be homogeneous by sodium dodecyl sulfate gel electrophoresis. Gel electrofocusing of neuraminidase revealed 1 major band (85-90%), pI 5.35 +/- 0.05, and 6 minor bands, whose pI ranged from 5.25 to 5.70, and each of which had catalytic activity. Arthrobacter neuraminidase is a monomeric glycoprotein of molecular weight 88 000, has an apparent Km of 7.8-10(-4) M for N-acetylneuraminlactose, is insensitive to inhibition by N-acetylneuraminic acid, and is about 2% carbohydrate by weight. The amino acid composition as well as the galactosamine and glucosamine content was determined. The enzyme can hydrolyze (alpha, 2-3), (alpha, 2-6), (alpha, 2-8) linkages. The active size of the enzyme appears to be inaccessible since no inhibition was observed by reagents known to modify sulfhydryl, lysyl, carboxyl, histidinyl, and argininyl residues. In contrast, N-bromosuccinimide at a 60-fold molar ratio to enzyme, gave complete inhibition. These results suggest that a tryptophan residue is essential for catalysis.

Isoelectric focusing of gamma globulins in cerebrospinal fluid from patients with multiple sclerosis

The technique of isoelectric focusing has been adapted for rapid clinical analysis for globulins in cerebrospinal fluid with use of commercially prepared horizontal-slab acrylamide gels. The globulin fraction is concentrated by ammonium sulfate precipitation, which allows more of the relevant protein to be applied, use of a wider range of total protein concentrations, and higher resolution than is true for previously described methods. Critical variables include a constant concentration and volume of IgG, a constant low temperature of the acrylamide gel, and sensitive staining with Coomassie Brilliant Blue G-250. The apparatus used is adaptable for other electrophoretic procedures in the clinical laboratory, and the use of commercially prepared gel slabs is more convenient, more reproducible, and requires less time than other methods.

Isoelectric focusing of gamma globulins in cerebrospinal fluid from patients with multiple sclerosis

The technique of isoelectric focusing has been adapted for rapid clinical analysis for globulins in cerebrospinal fluid with use of commercially prepared horizontal-slab acrylamide gels. The globulin fraction is concentrated by ammonium sulfate precipitation, which allows more of the relevant protein to be applied, use of a wider range of total protein concentrations, and higher resolution than is true for previously described methods. Critical variables include a constant concentration and volume of IgG, a constant low temperature of the acrylamide gel, and sensitive staining with Coomassie Brilliant Blue G-250. The apparatus used is adaptable for other electrophoretic procedures in the clinical laboratory, and the use of commercially prepared gel slabs is more convenient, more reproducible, and requires less time than other methods.

Membrane lipid metabolism of Bacillus Calmette-Guerin-induced rabbit alveolar macrophages

We examined the uptake of radiolabeled lysophospholipids and oleic acid by Bacillus Calmette-Guerin-induced rabbit alveolar macrophages either in the presence or absence of challenge particles. There was no difference in the uptake and metabolism of lysophospholipids by control or challenged cells for incubation periods up to 5 h. When incubated with [3H]oleic acid, challenged cells consistently exhibited a slightly greater uptake of radioactivity. Extraction of the whole cells revealed that the greater amount of radioactivity found in the challenged cells primarily was in triacylglycerol. There was no marked difference in the amount of radioactivity associated with the phospholipids in the whole cell extracts from control and challenged cells. When the macrophages were pre-labeled for 15 min with [3H]oleic acid and then reincubated in fresh medium in the presence or absence of autoclaved Escherichia coli B, more radioactivity was retained by the challenged cells, again in the form of triacylglycerol. Only in isolated plasma membrane fractions did we observe a difference in the amount of radioactivity associated with phospholipids from control and challenged cells. Plasma membranes isolated from Bacillus Calmette-Guerin-induced rabbit alveolar macrophages that had been incubated for 6 h with [3]oleic acid in the presence of E. coli B contained significantly higher level of radioactivity in all lipids than plasma membranes from control cells. Since the greatest and the most consistent difference between control and challenged cells is associated with the triacylglycerol molecule, it is postulated that this molecule may serve as a precursor in the synthesis of alveolar macrophage phospholipids, both by the reacylation pathway and the de novo pathway. It is possible that the high level of radiolabeled phospholipid found in the plasma membrane arose via the de novo pathway following the cleavage of an acyl group as we have found cytidine diphosphocholine phosphotransferase in the plasma membrane fraction (Wang, P., DeChatelet, L.R., and Waite, M. (1977) Biochim. Biophys. Acta 450, 311--321).

Properties of an inducible extracellular neuraminidase from an Arthrobacter isolate

The elective isolation of a soil microorganism, tentatively assigned to the genus Arthrobacter, which produced an extracellular neuraminidase is described. The secretion of neuraminidase from washed cells in minimal medium required the presence of sialo-containing glycoproteins, whereas free N-acetyl-neuraminic asid of N-acetylmannosamine were poor inducers. No enzyme could be dected in the induction fitrated of cells, in the absence of inducer or in the culture filtrate of cells grown in a complete medium. The routine enzyme inducer was a hot-water extract of "edible bird's nest." Mild acid treatment (0.05 N H2SO4) of this extract increased enzyme activity two--to threefold and the specific activity about eightfold. Neuraminidase induction with acid-treated bird's nest was manifested at a linear rate for 6 h without increase in cell number. No other anticipated glycohydrolase or protease activities were foud. The amount of enzyme located within the cells was barely detectable as compared to that found in the induction filtrate. Experiments with chloramphenicol or chlortetracycline indicate that de novo protein synthesis was required for neuraminidase production and that this exoenzyme was not released from a preformed pool. Neuraminidase from this source has an apparent molecular weight of 87,000, a pH optimum of 5 to 6, and an apparent Km of 2.08 mg/ml for collocalia mucoid and 3.3 X 10(-3) M for N-acetylneuraminlactose and is insensitive both to Ca2+ ions and ethylenediaminetetraacetic acid. Preliminary studies indicate that the enzyme can hydrolyze alpha-2,3-, alpha-2,6-, or alph-2-8-N-acetylneuraminylglycosidic linkages. From total activity data and purification criteria, it would appear that this isolate can produce about 5 mg of enzyme per liter of induction medium.

Effect of metabolites and phosphorylase on the D to I conversion of glycogen synthase from human polymorphonuclear leukocytes

The D to I conversion of glycogen synthase from human polymorphonuclear leukocytes was examined both in a gel-filtered homogenate and in a preparation of glycogen particles with adhering enzymes, purified by chromatography on concanavalin A bound to Sepharose. It was found that glucose 6-phosphate as well as mannose 6-phosphate, glucosamine 6-phosphate, and 2-deoxy-glucose 6-phosphate activated the reaction, whereas the corresponding sugars were without effect. Mn2+ and Ca2+ increased the conversion rate by 51% and 27%, respectively, whereas Mg2+ and inorganic phosphate were without effect. Sodium fluoride inhibited the reaction completely. Glycogen inhibited the reaction in physiological concentrations and 0.5 mM glucose 6-phosphate was able to overcome this inhibition. MgATP greatly augmented the inhibition caused by glycogen in the glycogen particle preparation. This combined effect could be overcome by glucose 6-phosphate in concentrations from 0.1 to 1 mM. Phosphorylase alpha purified from human polymorphonuclear leukocytes inhibited the D to I conversion in a glycogen particle preparation. The inhibition was counteracted by glucose 6-phosphate and to a lesser degree by AMP. Phosphorylase beta was also inhibitory, but only at higher concentrations than phosphorylase alpha. No phosphorylase phosphatase activity was found in the glycogen particle preparation, which may indicate that chromatography on concanavalin A-Sepharose separates this enzyme from the synthase phosphatase or partially destroys the activity of a hypothetical common protein phosphatase.

Comparison of NADH and NADPH oxidase activities in granules isolated from human polymorphonuclear leukocytes with a fluorometric assay

A fluormetric method for the determination of pyridine nucleotides has been adapted for use in studying the reduced pyridine nucleotide oxidases in human polymorphonuclear leukocytes. In the presence of strong base the oxidized forms of the pyridine nucleotides form a highly fluorescent product. The small amounts of NAD(P) formed by the oxidase reactions can be determined with great sensitivity. This method has been compared to the radioisotopic assay for NADPH oxidation. Both methods gave essentially the same results in terms of nanomoles NADP produced by control, resting, and phagocytizing samples. Both NADPH and NADH oxidase activities were insensitive to cyanide. NADPH oxidation had a pH optimum of 5.5, while that for NADH appeared to be 6.0. Granules isolated from phagocytizing cells routinely showed more activity toward both substrates (two to threefold) than granules from resting cells. Both activities were located primarily in a granule fraction prepared by differential centrifugation. Oxidation of NADPH was routinely four to five times that of NADH at all except very high substrate levels. Measurable NADH oxidation was rarely seen below 0.80 mM NADH, while NADPH oxidation was easily measurable at 0.20 mM. One patient with chronic granulomatous disease was studied. At low substrate levels, there was no activity toward either substrate in granules isolated from either resting or phagocytizing cells of this patient, while granules isolated from normal control cells showed substantial activity at these substrate levels. Purification of the activities had been initiated with linear sucrose gradients. Both activities co-sediment to a very dense region of the gradient, a region different from that in which membrane or azurophil granules usually equilibrate. The peak gradient fractions show a 10-30-fold increase in specific activity over comparable granule fractions. These data suggest that the oxidase activities are associated with one enzyme that has different affinities for the two substrates ans support the contention that the oxidation of NADPH is responsible for the metabolic burst accompanying phagocytosis in human PMNL.

Enzymes of phospholipid synthesis in Bacillus Calmette-Guerin induced rabbit alveolar macrophage. Characterization and localization of cytidine diphosphocholine phosphotransferase and monoacylphospholipid acyltransferase

The rabbit alveolar macrophage is capable of renewing its plasma membrane by at least two metabolic pathways. It contains (1) a monoacylphospholipid acyltransferase, which catalyzes the synthesis of diacylphospholipids by recycling monoacylphospholipids produced by the action of phospholipases and (2) a cytidine diphosphocholine phosphotransferase (CDPcholine phosphotransferase), which catalyzes the last step in the synthesis de novo of diacylglycerophosphocholine. These activities have been characterized in the cell homogenate with respect to time, protein, pH optimum (for CDPcholine phosphotransferase), substrate specificity (for monoacylphospholipid acyltransferase) and cation requirement ( for CDPcholine phosphotransferase). Monoacylphospholipid acyltransferase activity is localized solely in the endoplasmic reticulum. On the other hand, the CDPcholine phosphotransferase activity can be measured in the endoplasmic reticulum and in the plasma membrane, characterized by both differential and gradient sedimentation techniques. In addition to the normal route of phospholipid synthesis in the endoplasmic reticulum, the rabbit alveolar macrophage may thus possess the capacity for in situ synthesis of phospholipids of plasma membrane as a mechanism for membrane renewal following phagocytosis.

The renal sympathetic system and juxtaglomerular cells in experimental renovascular hypertension

Marked reduction of the monoaminergic nerve fluorescence and catecholamine tissue content were demonstrated in the ischemic kidney of rats made hypertensive by unilateral renal artery stenosis (two-kidney Goldblatt hypertension). The nonischemic kidney showed a normal degree of fluorescence and catecholamine content. The electron microscope failed to demonstrate recognizable nerves around most of the glomerular arterioles of the ischemic kidney, whereas a normal rich innervation was observed in the nonischemic side. The juxtaglomerular index and renal renin content were elevated in the ischemic kidney and markedly reduced in the nonischemic kidney. Juxtaglomerular cells were present in the glomerular mesangium and ultrastructurally showed changes consistent with increased renin synthesis. The extent of disruption of the sympathetic system in renal hypertension might play a role in the degree of hypersecretory response of the juxtaglomerular cells to renal artery constriction.

Light and electron microscopic localization of acetylcholinesterase activity in the rat renal nerves

Acetylcholinesterase activity is shown in the renal nerves of the rat with the technique of Karnovsky and Roots. By light microscopy, the acetylcholinesterase-positive nerves are seen in association with blood vessels, including the glomerular arterioles, and occasionally with renal tubules. By electron microscopy the precipitate appears extracellularly around axons and varicosities. DFP inhibits the deposition of precipitate. Previous demonstration by serial section electron microscopy in the rat revealed that all nerves around the glomerular arterioles contain small dense-cored vesicles characteristic of adrenergic nerves, indicating that the acetylcholinesterase-positive nerves demonstrated here are likely to be adrenergic nerves containing acetylcholinesterase.

[Cutaneous leiomyosarcoma and osteomedullary plasmocytoma with the demonstration of IgA-kappa paraprotein in serum and skin tumor]

A dermal leiomyosarcoma associated with a still asymptomatic osteomedullary plasmocytoma with IgA paraproteinemia develop-d rapidly in a 78-year-old man. The same paraprotein type IgA kappa was identified, with distinct decrease in concentration, in serum, sarcoma-tissue, and in the tumour-surrounding skin area by m-ans of immunoelectrophoresis, radial immunodiffusion, and Ouchterlony test. The immunochemical identity of the paraprotein, the course of the disease as followed clinically and immunochemically, and several histological criteria are in favour of monoclonal origin of the paraprotein from malignant plasmocytoma cells. The accumulation of paraprotein in the sarcoma tissue is primarily explained by the marked blood congestion of the tumour. To our knowledge no report exists in the medical literature of an association of dermal leiomyosarcoma and early paraproteinemic plasmocytoma. This coincidence may be only of chance but we rather suggest an immunopathological relation of both tumors due to a partial immune insufficiency caused by the preceding plasmocytoma, resulting in a diminished immunological "surveillance" of the organism and favouring the development of a new malignant cell population (i.e. leiomyosarcoma).

Treatment of attacks in hyperkalaemic familial periodic paralysis by inhalation of salbutamol

In fifteen patients with hyperkalaemic familial periodic paralysis, inhalation of salbutamol alleviated hyperkaleamia and paralysis precipitated by exercise or oral administration of potassium chloride. In-vitro studies with rat soleus muscles indicated that the hypokalaemic effect of salbutamol is related to stimulation of the active coupled transport of sodium and potassium in muscle cells. Follow-up studies proved that the inhalation of salbutamol is a simple and adequate method for the treatment of the paralytic episodes in these patients.

Inactivation of glycogen phosphorylase of human polymorphonuclear leukocytes

Glycogen phosphorylase of human polymorphonuclear leukocytes is dephosphorylated during incubation of a gel-filtered cell extract. The dephosphorylated enzyme (b form) retains 25 per cent of the activity of the phosphoenzyme (a form) when measured without AMP but a high glucose-1-phosphate concentrations. The ratio of activity -AMP/+AMP for the a enzyme is 0.8-1.0 and for the b enzyme 0.2. Leukocyte phosphorylase is not activated by -SH groups, but the b enzyme is stimulated by 0.4 mol/1 Na2SO4. The phosphatase which catalyzes the conversion of phosphorylase a to b is inhibited by glucose-1-phosphate and AMP both a 14 degrees C and 25 degrees C. Glucose counteracts the AMP inhibition but not the glucose-1-phosphate inhibition at both temperatures. Glucose alone had no effect at 25 degrees C, but it accelerated the phosphatase reaction at 14 degrees C. Glucose-6-phosphate or glycogen alone or in the presence of AMP or glucose-1-phosphate did not affect the phosphatase reaction. From previous and present experiments it is concluded that the phosphorylase of human polymorphonuclear leukocytes is closely related to liver phosphorylase and that the inactivation of the enzyme is mainly controlled by AMP and glucose.

Amylo-1,60glucosidase deficiency (glycogenosis type III) in the Faroe Islands

Seven cases of glycogenosis type III (amylo-1,6-glucosidase deficiency) in two probably related families from the Faroe Islands are presented. The group of patients comprised two pairs of sibs. In a total of 78 members of the two families case histories were obtained and clinical examinations, analyses of amylo-1,6-glycosidase activity in erythrocytes and leucocytes, determinations of red cell, serum and enzyme groups as well as HL-A types were performed. In addition, all patients were subjected to studies of liver function. The distribution patients in these families supports the assumption of autosomal recessive inheritance. Heterozygotes could not be diagnosed with certainty by the methods of enzyme activity analysis employed. The incidence of glycogenosis type III with amylo-1,6-glucosidase deficiency was found to be high in the Faroe Islands.

Effect of methylprednisolone on some BCG-mediated changes in rabbit alveolar macrophage

The effect of methylprednisolone sodium succinate treatment on Bacillus Calmette-Guérin (BCG) immunization was examined in alveolar macrophages of New Zealand White rabbits. Intravenous BCG injection caused a marked increase in cell number and in the hexosemonophosphate shunt activity. There was also a selective augmentation in the activity of acid phosphatase and beta-glucuronidase and an increase in lysosomal density. Activity of the lysosomal phospholipases was decreased. Steroid treatment suppressed the BCG-induced increase in cell number, hexosemonophosphate shunt activity, acid phosphatase, and beta-glucuronidase, and prevented the increase in lysosomal density. On the other hand, steroid treatment increased the activity of the phospholipases to levels higher than either control values or those obtained with cells from BCG-treated rabbits.