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Biomedical subjects

B Pettersson

Publications and source records attributed to B Pettersson.

At least 145 records · Page 8Linked to original sources
PubMed1975

Extracellular enzyme system utilized by the fungus Sporotrichum pulverulentum (Chrysosporium lignorum) for the breakdown of cullulose. Functional characterization of five endo-1,4-beta-glucanases and one exo-1,4-beta-glucanase.

A strong synergistic response was observed between the five endo-1,4-beta-glucanases and the exo-1,4-beta-glucanase obtained from culture solutions of the rot fungus Sporotrichum pulverulentum (formerly called Chrysosporium lignorum), when these enzymes were allowed to degrade de-waxed cotton and Avicel. No synergism was observed if Walseth cellulose, an acid-swollen cullulose, was used. If de-waxed cotton was pretreated with endo-1,4-beta-glucanases, the exo-1,4-beta-glucanase enzyme released much more degradation products than from an untreated cotton...

Cellulase↗
PubMed1975

Studies on norepinephrine-induced efflux of free fatty acid from hamster brown-adipose-tissue cells.

Cells were isolated from brown adipose tissue of warm-adapted hamsters and the fate of free fatty acids released during norepinephrine-induced lipolysis was investigated. The isolated resting cells contain between 100-400 nmoles cell-associated free fatty acids per 10(6) cells; most preparations contained about 200 nmoles/10(6) cells. During norepinephrine-stimulated lipolysis, the level of cell-associated free fatty acids remains constant or decreases gradually, but does not increase, while the concentration of extracellular fatty acids increases linearly. The rate of norepinephrine-stimulated efflux of free fatty acids was 40 +/- 20 nmol X min-1 X 10(6) cells-1 (n = 11) at 37 degrees C. The data strongly indicate that brown adipose tissue can supply free fatty acids to the circulatory system in hamster.

Adenosine Triphosphate↗
PubMed1975

Extracellular enzyme system utilized by the fungus Sporotrichum pulverulentum (Chrysosporium lignorum) for the breakdown of cellulose. 1. Separation, purification and physico-chemical characterization of five endo-1,4-beta-glucanases.

Five endo-1,4-beta-glucanases (EC 3.2.1.4) have been separated from culture solutions OF THE ROT FUNGUS Sporotrichum pulverulentum (formerly called Chrysosporium lignorum) grown on powder cellulose as the sole carbon source. They have been extensively purified and characterized with regard to some physicochemical properties. The purifications have been carried out on a quantitative basis, the purity of the enzymes being tested in several ways. After purification they all showed one single protein band in analytical polyacrylamide electrophoresis, on dodecyl-sulphate gels and in analytical isoelectric focusing on flat-bed polyacrylamide gels. One exo-1,4-beta-glucanase has also been identified in the culture solution and separated from the endo-1,4-beta-glucanases. From the data obtained during the quantitative purification it has been possible to calculate that the ratio of activity between the five endoglucanases T1, T2a, T2b, T3a, and T3b in the culture solutions is 4:1:1:1:1. It has also been calculated that the weight ratio endoglucanase protein to exoglucanase protein is approximately 1:1. Flat-bed isoelectric focusing has been used for the identification of the individual endoglucanases and a new zymogram technique, useful for studies of carbohydrases in general, has been developed. The molecular weights, determined by ultracentrifugation, and calculated on the basis of a knowledge of the amino acid composition and carbohydrate content vary between 28200 and 37500. Small but significant differences in the amino acid compositions of the different endoglucanases have been found. The carbohydrate content varies between 0 and 10.5%, all but one of the enzymes being glycoproteins. For two of these the exact carbohydrate composition has been determined. Enzyme T1 contains 2 glucose and 19 mannose units per enzyme molecule while enzyme T2b contains 5 mannose, 7 galactose, 1 glucose and 1 arabinose unit per molecule.

Amino Acids↗
PubMed1975

Extracellular enzyme system utilized by the fungus Sporotrichum pulverulentum (Chrysosporium lignorum) for the breakdown of cellulose. 2. Activities of the five endo-1,4-beta-glucanases towards carboxymethylcellulose.

A complementary discussion is given of an earlier presented theory for viscometric determination of enzymic activity towards polymer substrates. Five different, purified endo-1,4-beta-glucanases from the fungus Sporotrichum pulverulentum have been characterised with respect to their molecular activities(Am) and Michaelis-Menten constants (Km). The errors in the Am and Km values are discussed. The Am value seems to be more valuable as a distinguishing parameter than the Km value.

Carboxymethylcellulose Sodium↗
PubMed1975

Extracellular enzyme system utilized by the fungus Sporotrichum pulverulentum (Chrysosporium lignorum) for the breakdown of cellulose. 3. Purification and physico-chemical characterization of an exo-1,4-beta-glucanase.

An exo-1,4-beta-glucanase from culture solution of the rot fungus Sporotrichum pulverulentum (formerly called Chrysosporium lignorum) grown on powder cellulose as the sole carbon source has been extensively purified and characterized with respect to some physico-chemical properties. The purification has been carried out in a five-step procedure comprising chromatography on DEAE-Sephadex, gel filtration on polyacrylamide P-150, activation on a Dowex 2-X8 anion exchanger, chromatography on Concanavalin A-Sepharose and chromatography on SP-Sephadex. The purified enzyme was found to be pure and homogeneous by analytical polyacrylamide electrophoresis, by electrophoresis on dodecylsulphate gels and by analytical polyacrylamide electrophoresis, by electrophoresis on dodecylsulphate gels and by analytical isoelectric focusing. A single symmetrical peak was obtained with the free zone electrophoresis method. The purification factor is about 15 and the yield of exo-1,4-beta-glucanase activity 7%. After purification, the enzyme showed no viscosity-decreasing activity towards carboxymethyl-cellulose solutions. The exo-1,4-beta-glucanase was isoelectric at pH 4.3 (4 degrees C). A molecular weight of 48600 was calculated on the basis of a knowledge of the partial specific volume, ultracentrifugation data and the amino acid composition. The enzyme contained no carbohydrate.

Amino Acids↗
PubMed1975

An outbreak of ornithosis.

An outbreak of ornithosis occurred in Lidköping, a small town in Southwest Sweden, in January 1967 through May 1969. 24 proved cases were known, aged from 10 to 72 years, 19 patients gave a history of contact with birds (parrots, canaries, parakeets), 13 of them with birds from the same pet shop. Five patients had visited the pet shop only once before their illness. Attempts to prove infection with ornithosis agent in 7 birds from the pet shop were unsuccessful. Three patients, 2 of them in the same household, had no contact with birds and infection from person to person was strongly suspected. All patients had pneumonia. Fever, cough and headache were predominant clinical symptoms. There were relapses in 4 patients and 2 patients had symptoms of encephalitis. No deaths occurred.

Adolescent↗
PubMedDate not supplied

In vitro studies of biological effects of cigarette smoke condensate. I. Genotoxic and cytotoxic effects of neutral, semivolatile constituents.

Much of the biological activity of cigarette smoke resides in the neutral fraction of the particulate phase. Since the volatile constituents of this material, the semivolatiles, are accessible to selective filtration, some of the biological activity of cigarette smoke might be reduced. In view of this, the genotoxic and cytotoxic effects and the chemical composition of the semivolatile neutral material of a cigarette smoke condensate was investigated. Cigarette smoke condensate obtained from domestic American blend type cigarettes, was separated into a volatile, a nonvolatile and a semivolatile fraction. The semivolatile constituents were fractionated by liquid-liquid extraction into 4 subfractions: acids, phenols, bases and neutrals. The neutral material was separated further by silica gel chromatography into 7 subfractions of varying polarity. The major components of these were identified by gas chromatography-mass spectrometry. These fractions were studied using 4 in vitro short-term tests, of which 2, the Ames test and induction of sister-chromatid exchanges, provided information on their genotoxicity and the other 2 provided information on their cytotoxicity by measuring inhibition of cell growth and inhibition of oxidative metabolism. Sister-chromatid exchanges were induced by the neutral fraction and the 7 subfractions, the activities of which increased with increasing polarity. Neither the total neutral material, nor the subfractions showed any mutagenic activity in the Ames test. The cytotoxic effect of the fractions of medium polarity, was greater than that of the total neutral material, while the most and the least polar fractions were less toxic.

Adipose Tissue, Brown↗
PubMedDate not supplied

Semi-automated solid-phase DNA sequencing.

Increasing the efficiency of DNA sequencing necessitates the development of systems which reduce the need for manual operations by integrating template preparation, sequencing reactions, product separation and detection. A semi-automated system, whereby PCR-amplified biotinylated genomic or plasmid DNA is immobilized on streptavidin-coated magnetic beads, has been developed.

Automation↗
PubMedDate not supplied

Effects of waste incineration combustion emissions measured by some toxicity test systems.

The toxicity of combustion emissions from a municipal incineration plant was tested in a series of rapid test methods. The series included tests concerning cellular energy metabolism, cellular detoxification and mutagenicity. In the most sensitive test systems, brown adipocytes and mitochondria, an effect was observed at an emission extract concentration corresponding to 0.02 m3 of exhaust. The results indicate an influence on the mitochondrial level as well as the premitochondrial level. In Ames' test concentrations corresponding to up to 0.3 m3 exhaust did not increase the number of revertants, although the chemical analysis of the emission indicates that the combustion emission contains mutagenic substances.

Adipose Tissue, Brown↗
PubMedDate not supplied

Effects of air pollutants on the oxidative metabolism and phagocytic capacity of pulmonary alveolar macrophages.

Isolated rabbit pulmonary alveolar macrophages were found to be a convenient biological model system, relevant for studies of the toxicity of air pollutants. The phagocytic capacity and the oxygen consumption were used as test parameters and studied simultaneously on the same cells. The toxicity of extracts of airborne particles (phi less than 15 microns) collected in urban and rural areas was investigated and compared to a cigarette-smoke condensate. An extract of particles from a car tunnel was found to be the most toxic air sample, inhibiting phagocytosis as well as respiration of the macrophages at a concentration representing 5 m3 air/ml cell suspension. A corresponding sample collected on a roof of a five-storied building in the central area of a city (population 600,000) was found to inhibit phagocytosis but did not affect respiration. Further investigations revealed that one effect of the "tunnel" extract could be explained as an uncoupling of the mitochondrial respiratory control. Compared to the cigarette-smoke condensate, the toxicity of the air samples was infinitesimal.

Air Pollutants↗