Showing papers by "University of Graz published in 1978"

A rapid gas chromatographic method for the determination of poly- β -hydroxybutyric acid in microbial biomass

Abstract: The gas chromatographic method for the determination of poly-β-hydroxybutyric acid (PHB) consists of a mild acid or alkaline methanolysis of poly-β-hydroxybutyric acid directly without previous extraction of PHB from the cells; this is followed by gas chromatography of the 3-hydroxybutyric acid methylester. The method is characterized by high accuracy and excellent reproducibility, permitting determinations as low as 10−5 g/l. Only 4 h is required from sampling from the fermenter till completion of the PHB determination.

Seasonal Variation of Glutathione and Glutathione Reductase in Needles of Picea abies.

Abstract: In spruce (Picea abies) needles glutathione and glutathione reductase show a periodic seasonal variation with significantly increased levels during the winter. It is proposed that glutathione and glutathione reductase play an important role for the winter hardiness of leaves from evergreen plants.

The liquefaction (oncolysis) of malignant gliomas by a non pathogenic Clostridium.

Abstract: Vascular glioblastomas become liquefied when contaminated with spores of the non-pathogenic Clostridium butyricum M 55. The spores are administered by intracarotid injection. The oncolysis is complete one week after injection. The glioblastoma is converted into a brain abscess which is then operated on appropriately. Forty nine patients have been treated in this manner. The rate of recurrence, however, remained uninfluenced.

Formation and properties of reactive aldehydes.

Abstract: 4-Hydroxyalkenals react easily with SH groups in enzymes and structural proteins to give stable adducts in which the aldehyde is bound through a thioether linkage to the protein. This reaction represents the mechanism by which these compounds block certain metabolic processes (DNA, RNA and protein synthesis, respiration, glycolysis) and exert their antitumour activity. A highly significant inverse correlation exists between the number of hydroxypentenal-sensitive SH groups in the soluble proteins and the doubling time of 12 transplantable animal tumours. Hydroxyalkenals applied peritumourally completely prevent or significantly delay growth of the solid forms of four animal tumours. The almost non-toxic adducts of 4-hydroxypentenal-cysteine 1:1 and crotonal-cysteine 1:2 applied intraperitoneally prevent or inhibit growth of Ehrlich ascites tumour in mice. The possible formation of unsaturated aldehydes in vivo from lipids, carbohydrates and diamines is discussed.

The structure of human-plasma low-density lipoprotein B. An X-ray small-angle scattering study.

Abstract: 1. The X-ray small-angle scattering of human plasma lipoprotein B of the low-density fraction (Q = 1.016- 1.060 g . ~m-~) has been recorded to high precision at different electron density contrasts. 2. The overall structure of the particles is characterized by a quasi-spherical shape and radial symmetry. A maximum diameter of 23 nm and a molecular weight of 2.4 x lo6 have been determined. 3. The internal structure is described in terms of a model consisting of spherical layers with different electron densities indicating that the neutral lipids are arranged in the core of the molecule up to a radius of about 8 nm surrounded by a monolayer of free cholesterol, phospholipids and protein. The neutral lipids are shown to be in an ordered, liquid crystalline state at 4 “C and to undergo a thermotropic transition into a disordered state at higher temperatures.

Care and Handling of Univariate Outliers in the General Linear Model to Detect Spuriosity—A Bayesian Approach

Abstract: We deal with the situation covered by the univariate general linear model, that is, it is intended that n observations be generated in accordance with the usual model y = Xβ + e however, it is feared that k of the observations are spurious, that is, not generated in the manner intended, so that for an unknown set of k distinct integers, say (i 1, … ik ), a subset of the first n integers, we have, specifically, that ytj , = x tj ′, β + a j , + ∊ tj , where in general x t ′ denotes the t-th row of X, and where (a 1, …, a k ), so called shift parameters, are such that – ∞ < a j , < ∞. In this paper, we discuss the posterior distribution of β, when indeed it is assumed a priori that any given set of k observations has uniform probability I/( n k ) of being spurious. The properties of the posterior of β are discussed, and the results used in an example using data generated from a response surface design. Ad hoc procedures are discussed for gaining information on k, when k is unknown. These ad hoc procedures ar...

PGE-release, blood flow and transmucosal water movement after mechanical stimulation of the rat jejunal mucosa.

Abstract: 1. The influence of weak mechanical stimulation of the jejunal mucosa in vivo on PGE-release, on intestinal blood flow and transmucosal water movement was studied in rats. 2. Mechanical stimulation of the mucosa increased PGE-release into the venous outflow and into the gut lumen. This increase is followed by an increase in intestinal blood flow and transmucosal movement of tritiated water in both directions. 3. Pretreatment of the rat with idomethacin reduced the effect of mechanical stimulation on PGE-release. Indomethacin further reduced the increase in blood flow and in secretion of tritiated water. Absorption of tritiated water was not changed in these experiments. 4. Pretreatment of the rat with atropine (1 mg/kg, i.p.) or perfusion of the gut with methysergide (10 μg/ml) did not influence the increase in intestinal blood flow after mechanical stimulation. 5. It is suggested that enhanced intestinal blood flow and transmucosal movement of tritiated water after mechanical stimulation are mainly provoked by a preceding release of PGE. 6. It is further supposed that such a mechanism may be physiologically involved in regulation of intestinal blood flow and transmucosal water movement during food intake.

Elimination of substance P from the circulation of the rat and its inhibition by bacitracin.

Abstract: 1. Substance P (SP) was infused at different sites of the circulation of the rat. The animal's own salivary response was used as a bioassay to assess the amount of SP not eliminated when SP was infused into different vascular regions. 2. The highest degree of elimination of SP occurred in the liver and in the hind limbs, followed by the kidney. Elimination was low in the lungs and absent in the cerebral vessels. 3. SP was destroyed by rat plasma in vitro. This was a temperature dependent process. 4. Simultaneous infusion of bacitracin potentiated the effect of SP on salivary secretion. The degree of potentiation was dependent on the dose of bacitracin. It acted presumably by inhibiting the enzymatic inactivation of SP in the liver and in peripheral vascular beds. An interaction between bacitracin and SP on the SP receptors of the salivary glands could be excluded. 5. In contrast to the pronounced inhibition of the inactivation of SP by bacitracin in vivo, the in vitro inactivation of SP by rat plasma and in the isolated perfused rat hind quarter was hardly influenced by bacitracin. These results indicate an inactivation of circulating SP both by bacitracin sensitive and bacitracin insensitive enzymes. 6. The high degree at which SP is eliminated in the liver raises the question whether sufficient intestinal SP with be able to reach a distant organ to exert there a hormonal action or whether the SP present in the intestinal tract acts only locally.

Orbiviruses of the Kemerovo complex and neurological diseases

Abstract: The viruses of the Kemerovo complex, genusOrbivirus, family Reoviridae, are widely distributed in the habitats ofIxodes ticks in Eurasia. Their incidence in ticks sometimes surpasses that of the tick-borne encephalitis virus (TEV).

Thermotropic Changes in the Surface Structure of Lipoprotein B from Human‐Plasma Low‐Density Lipoproteins

Abstract: The lipoprotein B fraction of human-plasma low-density lipoproteins was labeled with (a) spin-label analogues of stearic acid I(m/n), the N-oxyl-4′,4′-dimethyloxazolidine derivatives of 5-oxo-, 12-oxo-, and 16-oxostearic acid, I(12/3), I(5/10), and I(1/14), respectively, and (b) a spin-label analog of maleimide (3-maleimido-2,2,5,5-tetramethyl-1-pyrrolidinyloxyl) bound covalently to the protein moiety. Electron spin resonance spectra were measured in the temperature range from 4 °C to 50 °C. The evaluation of the spectra yielded the following results. 1 The stearic acid spin labels I(m/n) show a reversible transition in their motional freedom at temperatures between 25 and 30 °C. This effect is stronger for labels I(1/14) and I(5/10) than for I(12/3). The polarity of their environment decreases in a sigmoidal way between 15 and 40 °C for labels I(12/3) and I(5/10). No polarity changes are observed with label I(1/14). 2 Below the transition the motional and polarity characteristics of I(m/n) are dominated by lipidprotein interaction, whereas above 30 °C the spectral parameters approach the situation of a model system of phosphatidylcholine-cholesterol. 3 The protein-bound spin label shows two spectral components arising from weakly and tightly immobilized binding sites, the ratio of the former to the latter increasing strongly between 25 and 30 °C concomitantly with a decrease in the separation of the two signals. The combined results indicate reversible changes in the fine structure involving both protein and polar lipids at the surface of lipoprotein B which correlate to the thermotropic transition of the apolar lipids in the particle core.

Uptake of proteoglycans and sulfated glycosaminoglycans by cultured skin fibroblasts.

Abstract: Pinocytosis and degradation of [35S]proteoglycans [35S]glycosaminoglycan chains were studied in cultured skin fibroblasts. Proteoglycans were obtained from fibroblast secretions, glycosaminoglycan chains either by β-elimination of proteoglycans or from secretions of fibroblasts grown in the presence of d-xylose or P-nitrophenyl-β-d-xyloside, respectively. The following results were obtained. 1 The uptake of proteoglycans as well as of glycosaminoglycan chains is dose-dependent and follows saturation kinetics. The maximal rate of pinocytosis og glycosaminoglycan chains induced by xylose and P-nitrophenyl-β-d-xyloside is only about 25% of that of proteoglycans as determined on the basis of the sulfate content. On a molar basis the maximal uptake rate for proteoglycans is 10-fold lower than for free glycosaminoglycan chains, but proteoglycans have a higher affinity than chains for the proposed receptors. 2 Uptake is followed by degradation. Its relative proportion is inversely related to the amount of endocytosed material. 3 Unlabeled proteoglycans compete for the uptake of [35S]proteoglycans, but protein-free proteoglycan chains are inefficient competitors at the doses used. 4 In case of [35S]glycosaminoglycans induced by xylose and P-nitrophenyl-β-d-xyloside, competition for uptake occurs by the addition of unlabeled glycosaminoglycan chains and of hybrid chondroitin-sulfate-dermatan-sulfate decasaccharides, but not by the addition of smaller saccharide fragments.

PGE-mediated laxative effect of diphenolic laxatives.

Abstract: 1 In the tied off colon of the anaesthetized rat in situ, the effect of diphenolic laxatives (bisacodyl and phenolphthalein) and of osmotic laxatives (mannitol, sodium sulfate and lactulose) on water net flux was studied All the laxatives reduced water net flux from lumen to blood or reversed it into water net flux from blood to lumen Pretreatment with indomethacin reduced or abolished the effect of the diphenolic laxatives on water net flux but did not change the effect of the osmotic laxatives 2 In the perfused colon of the rat in situ, the effect of the diphenolic and the osmotic laxatives on water net flux and on PGE-release into the colonic lumen was investigated All laxatives reduced water net flux from lumen to blood in this preparation, too PGE-release into the lumen during perfusion with osmotic laxatives was not different from the control The diphenolic lexatives increased PGE-release dosedependently about 2-fold 3 Intraluminal perfusion of the jejunal loop of the rat in situ with bisacodyl increased intestinal blood flow by about 50% Addition of indomethacin to the perfusion fluid abolished this increase 4 It is concluded that diphenolic laxatives exert their laxative action at least partially via stimulation of intestinal PGE-biosynthesis

A comparison of X-ray small-angle scattering results to crystal structure analysis and other physical techniques in the field of biological macromolecules.

Abstract: In principle, there exist two ways to contribute to structure determination of macromolecules by X-ray diffraction: (a) by analysing diffraction data obtained from the crystalline state, and (b) by interpretation of X-ray small-angle scattering from particles in solution.The brilliant achievements of X-ray crystal-structure analysis of macromolecules, initiated by the works of Perutz on heamoglobin and Kendrew on myoglobin, are well known and it is evident that its detailed elution of secondary, tertiary and quaternary structure cannot be matched by any other means. However, a number of necessary prerequisites for a successful application, as, for example, the availability of well-defined crystals and heavy atom labelled derivatives thereof to surmount the problem of phase determination are not always given.

Ylide von Heterocyclen, II: Iodonium- und Pyridinium-Ylide von Malonylheterocyclen

Abstract: Die Reaktion von Malonylheterocyclen wie 4-Hydroxycumarin (1a) oder -carbostyril (1b) mit (Diacetoxyiod)benzolen 2 liefert in guten Ausbeuten die Iodonium-Ylide 3. Bei der saurekatalysierten Umsetzung von 3 mit Pyridin oder Isochinolin erhalt man die entsprechenden Ylide 4, wahrend ohne Saurekatalyse eine Umlagerung zu den 4-Aryloxy-3-iod-Verbindungen 5 eintritt. Diese geben bei reduktiver Entiodierung die 4-Aryloxy-Verbindungen 6. Durch Photocyclisierung bilden 5a und 6a Coumestan (8). Mit HCl reagiert 3b zum 3-Chlor-4-hydroxy-carbostyril (7). Ylides of Heterocycles, II: Iodonium- and Pyridinium Ylides of Malonyl Heterocycles The reaction of malonyl heterocycles such as 4-hydroxycoumarin (1a) or -carbostyril (1b) with (diacetoxyiodo)benzenes 2 gives the iodonium ylides 3 in good yield. Acid-catalyzed treatment of 3 with pyridine or isoquinoline leads to the corresponding ylides 4, while 3 rearranges to 4-aryloxy-3-iodo compounds 5 under the same conditions in the absence of acids. Reductive deiodination of 5 yields the 4-aryloxy compounds 6. By photocyclization 5a und 6a react to coumestan (8). With HCl 3 is converted into 3-chloro-4-hydroxycarbostyril (7).

Mesoionische Sechsringheterocyclen, X: Synthese und Reaktionen mesoionischer 1,2,3‐Triazine

Abstract: Die Reaktion der (Chlorcarbonyl) ketene 1 mit cyclischen Saureamiden wie 2-Pyridon (2) und 2 Chinolonen (8) fuhrt zu bicyclischen mesoionischen Oxazinen (3 und 9). Diese setzen sich mit Phenylisocyanat unter 1,4-dipolarer Cycloaddition und CO2 - Eliminierung zu den Pyrimidin-Betainen 6 und 10 um, Mit Acetylendicarbonsaureester reagiert 3 zum Chinolizinondicarbonsaureester. 7. Die instabileren monocyclischen Oxazin- Betaine 13 werden aus N - substituierten aromatischen Saureamiden 12 und 1 unter Zusatz von Triethylamin erhalten. Hohere Reaktionstemperaturen fuhren dagegen unter Umlagerung zum isomeren Chinolindion 15. 2-Phenylacetamid (17) als aliphatisches N-unsubstituiertes Saureamid gibt das Oxazinon 18. Mesoionic Six-membered Heterocycles, XI. Synthesis and Reactions of Mesoionic 1,3-Oxazines The reaction of (chloroformyl) ketenes 1 with cyclic amides such as 2-pyridone (2) and 2-quinolones (8) leads to bicyclic mesoionic oxazines (3 and 9). With phenyl isocyanate these compounds are converted into pyrimidine betaines (6 and 10) by 1, 4-dipolar cycloaddition and elimination of CO2 With acetylenedicarboxylate 3 yields the quinolizinonedicarboxylate 7. The more unstable monocyclic oxazine betaines 13 are formed from N-substituted amides 12 and 1 in the presence of triethylamine. Higher reaction temperature leads by rearrangement to the isomeric quinolinedione 15. However, 2-phenylacetamide (17) as an aliphatic N-unsubstituted amide gives the oxazinone 18.

Preparation of choline and ethanolamine plasmalogens by enzymatic hydrolysis of the accompanying diacyl analogs

Abstract: Sir: Alk-l-enyl acyl glycerophospholipids (plasmalogens) occur only in association with their diacyl and alkyl acyl analogs, and the three species are not separable~ Procedures have been devised to remove the diacyl glycerophospholipids by selective enzymatic or chemical hydrolysis, but no method is available to separate alkyl acyl from alk-l-enyl acyl glycerophospholipidso Phospholipase A 2 from Crotalus atrox (1), phospholipase C from Clostridium perfringens (2), and phospholipase D from cabbage (3) hydrolyze diacyl phosphatidylcholine more rapidly than the corresponding alk-l-enyl acyl and alkyl acyl glycerophosphocholineso By alkaline hydrolysis under very mild conditions (4), d i acy l glycerophospholipids are deacylated more rapidly than the alkyl acyl or alk-l-enyl acyl analogs. Since all these methods make use of gradual differences in the reactivitity of ether ester and diester glycerophospholipids, a certain amount of the desired plasmalogen will also be hydrolyzed, and the final yield will be reduced. Furthermore, the enzymatic methods are applicable only to choline glycerophospholipids. Woelk et al. (5) described the isolation of choline and ethanolamine plasmalogens from the c o r r e s p o n d i n g phospholipid fractions obtained from bovine heart and brain, respectively, employing highly purified lipase from porcine pancreas, which cleaves specifically primary acyl ester bonds of diacyl glycerophospholipids. Alkyl acyl and alk-l-enyl acyl glycerophospholipids are not attacked by this enzyme~ Choline and ethanolamine plasmalogens were thus obtained in high yield (73% and 74%, respectively) and purity (98%)~ This method has considerable advantages, but its genera l application appears to be limited because highly purified pancreatic lipase is not commercially available. This led us to propose the use of lipase from Rhizopus arrhizus, which has the same specificity for primary acyl ester groups as has pancreatic lipase (6); it can be purchased in highly purified form~ Ethanolamine and choline glycerolipids were isolated from calf brain and beef heart lipids, respectively, by a combination of column chromatography and thin layer chromatography (TLC), employing established methods. The plasmalogen content (52% in the ethanolamine phospholipids and 43% in the choline phospholipids) was measured by the iodine method (7), alkyl acyl glycerophospholipids were quantitated as alkali and acid stable lipids (8), and phospholipid phosphorus was determined by the method of Bartlett (9). Identical procedures were followed for the treatment of both the choline and ethanolam i ne glycerophospholipid fractions with lipase. The lipid (100 mg) was dispersed in 20 ml of buffer [40 mM Tris-HC1, pH 7.6, 0.1 M NaC1, 3 mg/ml Na-deoxycholate (Merck, Darmstadt), 4~ mg/ml bovine serum albumin (Calbiochem), 5 mM CaC12] by shaking for 10 min, followed by sonication for 20 sec at 0-5 C (Braun Sonic 300 S, 50 W). After addition of 100 /.tl (1 rag, 6000 I.E.) of lipase from Rhizopus arrhizus (Boehringer, Mannheim), the mixture was incubated with shaking at 25 C for 2 hro After incubation, the lipids were extracted by the addi t ion of 100 ml chloroformmethanol, 2: 1. The lower phase was evaporated to dryness, and the residue was dissolved in chloroform-methanol, 2:1. Plasmalogens (together with accompanying alkyl acyl glycerophospholipids) were isolated by preparative TLC on Silica Gel H, with chloroformmethanol-water, 65: 25: 4, as developing solvent~ Chromatographically pure ethanolamine and choline plasmalogens were obtained with a yield of 80%, based on the amount of plasmalogen present in the ethanolamine and choline phospholipid fractions~ The aldehyde:P ratio was 0~ and 0.93, respectively~ Deviation from unity was due to the presence of alkyl acyl g lycerophosphol ipids (3% in ethanolamine plasmalogen and 7% in choline plasmalogen) which were identified and quantitated after alkaline and acidic hydrolysis (8) of the plasmalogen fraction~ The ratio alk-l-enyl:alkyl groups was the same in the respective substrates and final products, indicating that there is no selective loss of one of the two types of ether phospholipids during the isolation procedure.