The structure of a glycopeptide (GP-II) isolated from Rhizopus saccharogenic amylase.
(1/1858)
Mild alkaline treatment of glycopeptide (GP-II) resulted in the loss of 1 mole of serine and 5 moles of threonine per mole of GP-II, suggesting the presence of O-glycosyl bonds between 1 serine and 5 threonine residues and carbohydrate chains. Treatment of GP-II with alkaline borohydride released only disaccharide. Methylation studies of the carbohydrate moiety gave 2,3,4,6-tetra-O-methyl and 2,4,6-tri-O-methyl derivatives of mannose in a ratio of approximately 1:1. In addition, one step of Smith degradation resulted in the loss of about 6 residues of mannose per mole of GP-II. Moreover, alpha-mannosidase [EC 3.2.1.24] liberated about 6 residles of mannose per mole of GP-II. On the basis of these data, the structure of the carbohydrate moiety of GP-II was confirmed to be 3-O-alpha-mannosylmannose. The amino- and carboxyl-terminal amino acids of GP-II were determined to be threonine and serine, respectively. On reductive cleavage of N-proline bonds with metallic sodium in liquid ammonia, 2 moles of alanine per mole of GP-II were lost. From the compositions of three fragments isolated from the reductive cleavage products, the amino acid sequence of the peptide portion of GP-II was determined. Based on these data, a probable structure was proposed for GP-II. (+info)
Purification of gibberellic acid-induced lysosomes from wheat aleurone cells.
(2/1858)
Using isopycnic density gradient centrifugation, lysosomes were concentrated in a single region of a sucrose-Ficoll gradient (p = 1-10 g cm-3), well separated from most other cell organelles. Gibberellic acid-induced lysosomes were found to be rich in alpha-amylase and protease but not ribonuclease. The lysosomal band also contained a majority of the NADH2-cytochrome c reductase, a marker enzyme for endoplasmic reticulum, found in the gradient. Examination of electron micrographs revealed that a purified band of lyosomes contained at least 3 vesicle types, ranging in size from 0-1 to 0-5 mum. The significance of these findings to proposed mechanisms of action of gibberellic acid is discussed. (+info)
Detection of viruses and body fluids which may contain viruses in the domestic environment.
(3/1858)
The domestic environment was investigated for the presence of viruses and body fluids that may contain viruses. A range of surfaces in 39 homes (17 visited on 2 occasions) were sampled by swabbing and analysed using cell culture, reverse transcription polymerase chain reaction for enteroviral RNA, haemoglobin as a marker for blood, amylase as an indicator of urine, saliva and sweat, and protein as an indicator of general hygiene. Haemoglobin was found on 1.9% of surfaces sampled and of the positive samples 30% were from articles frequently handled. Amylase (> 5 U/l) was found in 29.3% of samples tested. Protein was found in 97.8% of samples tested. Enteroviral RNA, indicating the presence of virus, was detected in 3 out of 448 samples tested; they were from a tap handle, telephone handpiece and a toilet bowl. No viruses were isolated in cell culture, however significant problems were encountered with bacterial and fungal contamination. This work demonstrates that only testing environmental samples for bacteria and ATP may not give a total view of the microbiological problem in the home. A range of test methods is useful to gain a broad view of the problems of hygiene in the home and to allow comparative studies of specific areas such as the kitchen and bathroom. (+info)
Underestimation of acute pancreatitis: patients with only a small increase in amylase/lipase levels can also have or develop severe acute pancreatitis.
(4/1858)
BACKGROUND: In most treatment studies on acute pancreatitis, pancreatologists base their diagnosis on amylase/lipase levels more than three times above the upper limit of normal (>3n) and thus exclude patients with smaller enzyme level increases. The recommendations derived from the results of treatment studies do not take into account such patients. Non-pancreatologists frequently believe that only patients with high enzyme levels have a serious prognosis. AIMS: To question the assumption that high enzyme levels indicate severe, and conversely low enzyme levels indicate mild, acute pancreatitis. PATIENTS/METHODS: This retrospective study includes 284 consecutive patients with a first attack of acute pancreatitis. The cause was biliary in 114 (40%) patients, alcoholism in 83 (29%), other in 21 (7%), and unknown in 66 (23%). Patients were divided into two groups according to their serum enzyme levels (amylase: 3n, n = 196; lipase: 3n, n = 233). Renal impairment, indication for dialysis and artificial ventilation, development of pseudocysts, necessity for surgery, and mortality were taken as parameters of severity. RESULTS: The incidence of severity was the same for both the 3n groups. CONCLUSIONS: The severity of acute pancreatitis is independent of the elevation in serum amylase/lipase level (3n) on admission. Patients with only a slight increase can also have or develop severe acute pancreatitis. Patients with +info)
Genetic regulation of tissue-specific expression of amylase structural genes in Drosophila melanogaster.
(5/1858)
Laboratory strains of Drosophila melanogaster were screened for spatial variations in adult midgut alpha-amylase (1,4-alpha-D-glucan glucanohydrolase, EC 3.2.1.1) expression. No strain-specific differences were found anteriorly, but three patterns of activity were discerned in the posterior midgut: A, activity throughout most of the region; B, activity in the anterior part of the region; and C, little or no activity. Alleles of a control gene, map, are responsible for this tissue-specific regulation of activity; e.g., mapA homozygotes produce the A pattern and mapC homozygotes the C pattern. The map locus was placed at 2--80 +/- on the genetic map of chromosome 2R, about two crossover units distal to the Amy structural gene region for alpha-amylase. Electrophoretic studies showed that mapA is trans acting in mapA/mapC flies, allowing expression of amylase isozymes coded for by genes on the opposite chromosome. The map gene behaves as a temporal gene that is clearly separable from the tightly linked, duplicated Amy structural genes. (+info)
Modes of action of acarbose hydrolysis and transglycosylation catalyzed by a thermostable maltogenic amylase, the gene for which was cloned from a Thermus strain.
(6/1858)
A maltogenic amylase gene was cloned in Escherichia coli from a gram-negative thermophilic bacterium, Thermus strain IM6501. The gene encoded an enzyme (ThMA) with a molecular mass of 68 kDa which was expressed by the expression vector p6xHis119. The optimal temperature of ThMA was 60 degrees C, which was higher than those of other maltogenic amylases reported so far. Thermal inactivation kinetic analysis of ThMA indicated that it was stabilized in the presence of 10 mM EDTA. ThMA harbored both hydrolysis and transglycosylation activities. It hydrolyzed beta-cyclodextrin and starch mainly to maltose and pullulan to panose. ThMA not only hydrolyzed acarbose, an amylase inhibitor, to glucose and pseudotrisaccharide (PTS) but also transferred PTS to 17 sugar acceptors, including glucose, fructose, maltose, cellobiose, etc. Structural analysis of acarbose transfer products by using methylation, thin-layer chromatography, high-performance ion chromatography, and nuclear magnetic resonance indicated that PTS was transferred primarily to the C-6 of the acceptors and at lower degrees to the C-3 and/or C-4. The transglycosylation of sugar to methyl-alpha-D-glucopyranoside by forming an alpha-(1,3)-glycosidic linkage was demonstrated for the first time by using acarbose and ThMA. Kinetic analysis of the acarbose transfer products showed that the C-4 transfer product formed most rapidly but readily hydrolyzed, while the C-6 transfer product was stable and accumulated in the reaction mixture as the main product. (+info)
Ultrastructural analysis of some functional aspects of Xenopus laevis pancreas during development and metamorphosis.
(7/1858)
Morphological studies using both light and electron microscope were carried out with the aim of characterizing cells present in the larval and adult pancreas of Xenopus laevis. The following cell types have been seen: (1) exocrine cells, with a very well developed r.e.r. (rough endoplasmic reticulum), well defined Golgi complexes and numerous large secretory granules (A cells); (2) cells without either r.e.r. or secretory granules but with a large number of well developed mitochondria (B cells); (3) endocrine cells often clustered in the typical islets and with small membrane-coated granules showing a very dense central core surrounded by a light halo (C cells). During development, the aspect is seen to change from an unorganized tissue in which the acinar structures are still not clearly visible (stage 42), to a more organized form in which the exocrine cells (A cells) are seen to be arranged around the lumen of the acinus together with some B cells. At the stages 54-56, an increasing number of acini surrounded both by A and B cells was observed. At about stage 61, large quantities of necrotic cells were seen and it became more difficult to individualize the acinar organization found in the preceding stages. Finally, there are no necrotic cells in the adult but only A, B cells which are organized in well developed acinar structures and C cells. The investigation also included a study of some pancreatic enzymes (lipase and amylase) synthesized during larval life. Lipase activity shows a peak at stage 54-56 in which the most well organized tissue of the entire larval life was observed. The activity then decreases, reaching a minimum at stage 66, after which it rapidly rises. Maximum amylase activity occurs at stage 51 after which there is a decrease, to a minimum at stage 66. The activity then remains at constant level. (+info)
A monoclonal anti-interleukin 8 antibody (WS-4) inhibits cytokine response and acute lung injury in experimental severe acute necrotising pancreatitis in rabbits.
(8/1858)
BACKGROUND: Interleukin 8 (IL-8) has recently been proposed to have an important role in mediating the development of the systemic sequelae associated with severe acute pancreatitis. AIMS: To define the role of IL-8 in acute pancreatitis by neutralising its effects with a monoclonal anti-IL-8 antibody (WS-4), in a rabbit model of severe acute pancreatitis. METHODS: Acute pancreatitis was induced by retrograde injection of 5% chenodeoxycholic acid into the pancreatic duct and duct ligation. Twenty rabbits were divided equally into two groups: acute pancreatitis controls received physiological saline and the treated group received WS-4, 30 minutes before induction of acute pancreatitis. RESULTS: Pretreatment of animals with WS-4 resulted in significant down regulation of serum IL-8 and tumour necrosis factor alpha (TNF-alpha) from three to six hours after induction of acute pancreatitis (p = 0.011 and 0.047 for IL-8 and 0.033 and 0.022 for TNF-alpha, respectively). In addition, a significant reduction in the CD11b and CD18 positive cells and the amount of interstitial neutrophil infiltration in the lungs from WS-4 treated animals was seen. In contrast, WS-4 did not alter the amount of pancreatic necrosis and the serum concentrations of amylase, lipase, calcium, and glucose. CONCLUSION: WS-4 cannot change the amount of pancreatic necrosis induced by injection of 5% bile acid, but does reduce the acute lung injury, presumably through inhibition of circulating IL-8 and TNF-alpha, and CD11b/CD18 in lung tissue. Therefore, a role of IL-8 in the progression of acute pancreatitis and the development of its systemic complications is suggested. (+info)