2351
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Chen G, Jiang C, Li S, Yang B, Jang D, Wang P, Yan J, He L. The role of the human caudate nucleus in acupuncture analgesia. ACUPUNCTURE ELECTRO 1982; 7:255-65. [PMID: 6131570 DOI: 10.3727/036012982816952053] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The role of the caudate nucleus in acupuncture analgesia was studied in 17 patients receiving caudate stimulation through chronic implanted electrodes to relieve intractable pain caused by late malignancy. Electrical stimulation of the head of the caudate nucleus provided relief from intractable pain in all 17 patients. The pain and pain tolerance threshold were elevated, the alteration in skin galvanic activity, respiratory movement and fingertip plethysmography elicited by a given painful stimulus were depressed. The analgesia required a period of induction and persisted for some time after cessation of stimulation; it showed no obvious segmental topography. These characteristics are similar to those observed in acupuncture analgesia. The effect of caudate stimulation was similar to that of electric needling in depressing the late component of the somatosensory evoked potentials (SEPs) recorded over the scalp and from the centrum medianum of the thalamus. Evoked potentials could be recorded from the caudate nucleus when an acupuncture point was electrically stimulated. The evoked potential record was a complex wave of positive and negative components, the peak latencies of main components being 100-180 msec for positive wave and 148-332 msec for negative wave components. The present study supports the supposition that the caudate nucleus may play a role in acupuncture analgesia. The possibility that the effect of caudate stimulation is brought on by inhibiting the activity of the medial thalamus is discussed.
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2352
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Barajas L, Wang P, Powers K, Nishio S. Identification of renal neuroeffector junctions by electron microscopy of reembedded light microscopic autoradiograms of semithin sections. JOURNAL OF ULTRASTRUCTURE RESEARCH 1981; 77:379-85. [PMID: 7321090 DOI: 10.1016/s0022-5320(81)80034-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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2353
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BonDurant RH, Darien BJ, Munro CJ, Stabenfeldt GH, Wang P. Photoperiod induction of fertile oestrus and changes in LH and progesterone concentrations in yearling dairy goats (Capra hircus). JOURNAL OF REPRODUCTION AND FERTILITY 1981; 63:1-9. [PMID: 7277307 DOI: 10.1530/jrf.0.0630001] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Oestrus and ovulation were induced in a group of 19 yearling dairy goats which had been maintained for 70 days on a 19 h/day photoperiod regimen. Six yearling females, raised under natural photoperiod, served as controls. An intact, light-treated male was introduced to each group 42 days after termination of the artificial lighting. Behavioural, endocrine and kidding observations indicated that 15 of the experimental females (79%) ovulated within 21-30 days after introduction of the male, that 12 (63%) conceived at the induced ovulation, and that 10 (53%) gave birth to live kids, while none of the controls ovulated during this time. The breeding season was advanced between 60 and 80 days. In experimental and control nannies there was a brief, small surge (320 +/- 42 pg/ml) of plasma progesterone which occurred 19.5 days after introduction of the male and which closely preceded oestrus in the nannies that ovulated and at 25 days in control females. Ovulatory surges of LH (to 70 ng/ml plasma) were closely associated with oestrus, and remained above basal levels for 9.0 +/- 0.75 h, in 7 experimental females. Two of 6 control nannies also showed LH surges but they did not ovulate.
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2354
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Guengerich FP, Wang P, Mason PS. Immunological comparison of rat, rabbit, and human liver NADPH-cytochrome P-450 reductases. Biochemistry 1981; 20:2379-85. [PMID: 6786332 DOI: 10.1021/bi00512a003] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
NADPH-cytochrome P-450 reductase (EC 1.6.2.4) preparations were purified to electrophoretic homogeneity from rat, rabbit, and human liver microsomes. These preparations had apparent monomer molecular weights (Mr's) of 72 000-74 000 and were catalytically active in reducing rat and rabbit liver cytochromes P-450 as well as cytochrome c. A form of the human liver reductase devoid of a peptide of about Mr 6000 was isolated in the absence of protease inhibitors; this enzyme catalyzed the reduction of cytochrome c but not cytochromes P-450. Rabbits were immunized with purified rat liver NADPH-cytochrome P-450 reductase and the resulting antibody preparation was used to examine the species specificity of the enzyme. Immunological differences among the three species were detected by using double-diffusion analysis, quantitative microcomplement fixation, and inhibition of enzyme activity. Microcomplement fixation techniques indicated immunological differences in both rat and human reductase preparations due to removal of a peptide of Mr 6000-8000; these differences were not detected by using double-diffusion analysis. The antibody inhibited rat liver microsomal d-benzphetamine N-demethylase activity to the same extent as NADPh-cytochrome c reductase activity, suggesting that the level of reductase controls the rate of this cytochrome P-450-mediated activity. On the other hand, the antibody was much less effective in inhibiting rat liver benzo[a]pyrene hydroxylase activity. The antibody exerted different effects in inhibiting d-benzphetamine N-demethylase and benzo[a]pyrene hydroxylase activities as compared to NADPH-cytochrome c reductase activity in human liver microsomes.
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2355
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Guengerich FP, Wang P, Mason PS, Mitchell MB. Immunological comparison of rat, rabbit, and human microsomal cytochromes P-450. Biochemistry 1981; 20:2370-8. [PMID: 6786331 DOI: 10.1021/bi00512a002] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Antibodies were raised in rabbits to electrophoretically homogeneous cytochromes P-450 isolated from rat and human liver microsomes. These antibodies were used to compare various forms of rat, rabbit, and human cytochromes P-450 present in microsomes and in purified preparations by using double-diffusion analysis, immunoelectrophoresis, quantitative microcomplement fixation, competitive radioimmune assay and inhibition of enzyme activity toward d-benzphetamine and benzo[a]pyrene. The results indicate that (1) at least some forms of cytochrome P-450 from the three species share certain common immunological determinants, (2) there are immunological differences between cytochromes P-450 isolated from the three species, (3) some immunological differences exist between cytochromes P-450 isolated from rats of different strains, (4) immunologically distinguishable forms of cytochrome P-450 exist within individual human liver samples, and (5) human liver samples obtained from different individuals contain immunologically different forms of cytochrome P-450. Quantitative microcomplement fixation techniques were used to assign immunological distances to different form of rat, rabbit, and human liver microsomal cytochrome P-450. Cross-reactivity was observed in all systems tested, and the extent of immunological similarity was dependent upon the particular assay used.
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2356
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Lin ZB, Wang P, Ruan Y, Guo QX. [Anti-inflammatory effect of beta, beta-dimethylacrylshikonin (author's transl)]. ZHONGGUO YAO LI XUE BAO = ACTA PHARMACOLOGICA SINICA 1980; 1:60-3. [PMID: 6461178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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2357
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Clausen T, Wang P, Orskov H, Kristensen O. Hyperkalemic periodic paralysis. Relationships between changes in plasma water, electrolytes, insulin and catecholamines during attacks. Scand J Clin Lab Invest 1980; 40:211-20. [PMID: 7003689 DOI: 10.3109/00365518009095569] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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2358
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Zhou ZD, Han CH, Wang P. [A study on the hypotensive action and mechanism of berbamine hydrochloride (author's transl)]. YAO XUE XUE BAO = ACTA PHARMACEUTICA SINICA 1980; 15:248-50. [PMID: 7457144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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2359
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2360
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Wang P, Mason PS, Guengerich FP. Purification of human liver cytochrome P-450 and comparison to the enzyme isolated from rat liver. Arch Biochem Biophys 1980; 199:206-19. [PMID: 6766706 DOI: 10.1016/0003-9861(80)90274-x] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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2361
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Guengerich FP, Wang P, Mason PS, Mitchell MB. Rat and human microsomal epoxide hydratase. Immunological characterization of various forms of the enzyme. J Biol Chem 1979; 254:12255-9. [PMID: 115882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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2362
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Guengerich FP, Wang P, Mitchell MB, Mason PS. Rat and human liver microsomal epoxide hydratase. Purification and evidence for the existence of multiple forms. J Biol Chem 1979; 254:12248-54. [PMID: 500710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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2363
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Guengerich F, Wang P, Mason P, Mitchell M. Rat and human microsomal epoxide hydratase. Immunological characterization of various forms of the enzyme. J Biol Chem 1979. [DOI: 10.1016/s0021-9258(19)86458-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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2364
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Lenz S, Kühl C, Wang P, Mølsted-Pedersen L, Orskov H, Faber OK. The effect of ritodrine on carbohydrate and lipid metabolism in normal and diabetic pregnant women. ACTA ENDOCRINOLOGICA 1979; 92:669-79. [PMID: 394554 DOI: 10.1530/acta.0.0920669] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
ABSTRACT
The metabolic effects of a one hour intravenous infusion of the β-2-receptor stimulating drug ritodrine were studied in seven normal pregnant women, three White class A pregnant diabetics and eight White class B-D pregnant diabetics.
During ritodrine infusion all subjects in the three groups exhibited increases in plasma glucose (1.0, 1.6 and 2.1 mmol/l respectively), free fatty acids (360, 850 and 1150 μmol/l), lactate (0.43, 0.80 and 0.86 mmol/l) and β-hydroxybutyrate and decreases in standard bicarbonate. The rise in plasma glucose, free fatty acids and lactate was more pronounced in insulin treated diabetic. The rises in β-hydroxybutyrate and decreases in standard bicarbonate were of the same magnitude in all three groups. Plasma potassium fell in all subjects, whereas no detectable changes in plasma sodium were observed.
The endocrine pancreatic function was assessed by measuring plasma insulin (White class A and normals), C-peptide (White class B-D) and glucagon (all subjects). Plasma insulin increased in normals (22 μIU/ml) and White class A diabetics (33 μIU/ml), whereas plasma C-peptide of the insulin treated patients (White class B-D) were below measurable concentrations. Plasma glucagon and cortisol concentrations were not influenced by ritodrine.
The results suggest that the diabetogenic changes induced by ritodrine are augmented with the severity of diabetes but not ascribable to a diabetes-like change in the function of the endocrine pancreas.
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2365
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Barajas L, Wang P. Localization of tritiated norepinephrine in the renal arteriolar nerves. Anat Rec (Hoboken) 1979; 195:525-34. [PMID: 507406 DOI: 10.1002/ar.1091950311] [Citation(s) in RCA: 41] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The innervation of the glomerular arterioles was investigated by light and electron microscopy autoradiography for localization of exogenous tritiated norepinephrine. By light microscopy accumulations of grains were seen associated with afferent arterioles and in lesser numbers with efferent arterioles and neighboring tubules. Accumulations of grains were noted to be in contact with juxtaglomerular granular cells. Electron microscopy autoradiography revealed that nearly two-thirds of the silver grains were on axons. Most of the label was on varicosities packed with small, clear and dense-cored, vesicles. Most varicosities, including those in contact with smooth muscle, juxtaglomerular granular or tubular cells, were labeled. Some varicosities which appeared unlabeled in a given section were labeled in subsequent sections. These findings are consistent with the notion that the glomerular arterioles are innervated mainly by adrenergic nerves. This view is supported by the previously reported observations of the concomitant virtual disappearance of fluorescent and acetylcholinesterase-positive nerves from the region of the glomerular arterioles after two injections of six-hydroxydoapmine (a drug which selectively destroys adrenergic nerves) and the presence of small dense-cored vesicles in all axons of the juxtaglomerular region when examined by serial section electron microscopy.
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2366
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Wang P, Schafer D, Miller CA, Tanenbaum SW, Flashner M. Induction and regulation of neuraminidase synthesis in Arthrobacter sialophilus. J Bacteriol 1978; 136:874-9. [PMID: 721778 PMCID: PMC218520 DOI: 10.1128/jb.136.3.874-879.1978] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
A variety of N-acetylneuraminic acid (AcNeu) derivatives and analogs were examined as inducers of the extracellular neuraminidase of Arthrobacter sialophilus. Neuraminidase inductions were primarily studied with tryptone-yeast extract-grown cells after washing and resuspension in a defined replacement medium. The addition of readily metabolizable carbon sources to the latter, such as 0.1% casein hydrolysate, glutamate, or glucose, enhanced enzyme synthesis. Enzyme appearance occurred after a lag in the uptake of inducers, suggesting the participation of a co-inducible transport system. Neuraminidase formation during exponential growth in the presence of AcNeu ceased after depletion of this end product from the medium. It was found, besides AcNeu, that its methyl ester, 2-deoxy-2,3-dehydro-N-acetylneuraminic acid and 2-deoxy-2,3-dehydro-N-acetyl-neuraminic acid methyl ester are each active inducers, whereas beta-anomers of AcNeu-ketosides are not. These results, in comparison to known enzyme specificity, have revealed significant differences and parallels between the inductive and catalytic processes for neuraminidase. In particular, it would appear that the free carboxylate and oxygenation at C-2 of AcNeu, essential for enzyme catalysis with traditional AcNeu substrates, are not necessary for induction and, furthermore, that transition state analogs can specifically induce this enzyme. The failure to observe catabolite repression in this system is discussed in relation to the intermediary metabolism of the genus Arthrobacter.
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2367
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Barajas L, Wang P. Myelinated nerves of the rat kidney. A light and electron microscopic autoradiographic study. JOURNAL OF ULTRASTRUCTURE RESEARCH 1978; 65:148-62. [PMID: 731783 DOI: 10.1016/s0022-5320(78)90052-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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2368
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Miller CA, Wang P, Flashner M. Mechanism of Arthrobacter sialophilus neuraminidase: the binding of substrates and transition-state analogs. Biochem Biophys Res Commun 1978; 83:1479-87. [PMID: 697876 DOI: 10.1016/0006-291x(78)91388-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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2369
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Wang P, Tanenbaum SW, Flashner M. Purification and properties of Arthrobacter neuraminidase. BIOCHIMICA ET BIOPHYSICA ACTA 1978; 523:170-80. [PMID: 629985 DOI: 10.1016/0005-2744(78)90019-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
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.
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2370
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Trotter JL, Banks G, Wang P. Isoelectric focusing of gamma globulins in cerebrospinal fluid from patients with multiple sclerosis. Clin Chem 1977. [DOI: 10.1093/clinchem/23.12.2213] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
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.
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2371
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Trotter JL, Banks G, Wang P. Isoelectric focusing of gamma globulins in cerebrospinal fluid from patients with multiple sclerosis. Clin Chem 1977; 23:2213-5. [PMID: 72619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
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.
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2372
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Wang P, Waite M, Dechatelet LR. Membrane lipid metabolism of Bacillus Calmette-Guerin-induced rabbit alveolar macrophages. BIOCHIMICA ET BIOPHYSICA ACTA 1977; 487:163-74. [PMID: 322724 DOI: 10.1016/0005-2760(77)90053-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
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).
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2373
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Schultz DH, Shah VL, Shay W, Wang P. Diffusion of oxygen and carbon dioxide through blood flowing in a channel. Med Biol Eng Comput 1977; 15:98-105. [PMID: 192972 DOI: 10.1007/bf02442952] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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2374
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Flashner M, Wang P, Hurley JB, Tanenbaum SW. Properties of an inducible extracellular neuraminidase from an Arthrobacter isolate. J Bacteriol 1977; 129:1457-65. [PMID: 14924 PMCID: PMC235123 DOI: 10.1128/jb.129.3.1457-1465.1977] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
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.
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2375
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Wang P, Bantle G, Sorensen NB. Effect of metabolites and phosphorylase on the D to I conversion of glycogen synthase from human polymorphonuclear leukocytes. Biochim Biophys Acta Gen Subj 1977; 496:436-47. [PMID: 189843 DOI: 10.1016/0304-4165(77)90326-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
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.
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