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Biomedical subjects

H Gürtler

Publications and source records attributed to H Gürtler.

At least 19 recordsLinked to original sources
PubMed2000

Improved secondary metabolite production in the genus Streptosporangium by optimization of the fermentation conditions.

The cultivation of strains of the genus Streptosporangium in batch fermentations demonstrated that the optimal conditions for secondary metabolite production are completely different to those of the closely related genus Streptomyces. The dissolved oxygen tension (pO(2)) was identified as an important parameter for optimal production of secondary metabolites in submerged cultures. Extreme variations of this parameter by changes in aeration (gas flow), agitation system and stirrer speed showed a tremendous impact in production yields of all investigated strains. Finally, a 20-fold increase in productivity was observed by conditions of controlled oxygen excess compared to optimal fermentation conditions for Streptomyces strains.

Actinomycetales↗
PubMed2000

Kyanomycin, a complex of unusual anthracycline-phospholipid hybrids from Nonomuria species.

A blue secondary metabolite complex, named kyanomycin (2), in addition to epsilon-rhodomycinone (1), was detected in the mycelium extract of Nonomuria sp. NN 22303 by HPLC-diode array and HPLC-electrospray mass spectrometry screening. The chemical structures of the novel compounds were determined to be unusual anthracycline-phosphatidylethanolamine hybrids by spectroscopic and chemical degradation experiments.

Actinomycetales↗
PubMed1999

Plasma levels of catecholamines and lipolysis during starvation in growing pigs.

The aim of this study was to clarify the triggering mechanism of lipolysis in adipose tissue during feed withdrawal in pigs. Evaluation of blood samples drawn via an intravenous catheter from 10 growing pigs fasted for 60 h demonstrated, in addition to a haemodilution, a significant rise in plasma levels of non-esterified fatty acids (250 +/- 37 to 1427 +/- 144 mumol/l) and free glycerol (98 +/- 27 to 232 +/- 41 mumol/l) within 48 h of feed restriction, and thereafter the concentrations levelled off. The pigs also showed a significant decrease in plasma levels of glucose (6.01 +/- 0.20 to 4.62 +/- 0.12 mmol/l) within 48 h of fasting, followed by repeated increase until the end of the experimental period. A significant decrease in plasma insulin-like growth factor I (84 +/- 13 to 65 +/- 7 ng/ml) was observed after 16 h, which continued during the whole period of feed withdrawal. However, no significant changes in plasma levels of adrenaline and noradrenaline during the period of increased lipolysis were detected. Therefore, the observed stimulation of lipolysis in growing swine during fasting is not the result of an increase in plasma concentration of catecholamines.

Adipose Tissue↗
PubMed1998

Evidence of the existence of alpha 1B-adrenoceptors on hepatocytes of domestic fowl (Gallus domesticus).

In liver cell membranes of laying hens alpha 1-adrenergic receptors were characterized using 3H-prazosin. Specific binding was saturable and indicative of a single class of high-affinity binding sites with a KD of 0.40 +/- 16 nM and a Bmax of 390 +/- 38 fmol/mg membrane protein. Preincubation of membranes with chlorethylclonidine significantly diminished the binding of 3H-prazosin (Bmax = 99 +/- 14 fmol/mg membrane protein). Furthermore, competition experiments revealed a rank order of prazosin >> phentolamine = oxymetazoline >> WB 4101, with Ki values of 0.71 +/- 0.62, 20 +/- 6, 32 +/- 13, and 119 +/- 48 nM, respectively. These results suggest the existence of alpha 1B-adrenergic receptors in hen liver cell membranes.

Animals↗
PubMed1997

[Effect of insulin on glucose and and fat metabolism in ewes during various reproductive states in normal and hypocalcemia].

Metabolic indicators of glucose and lipid metabolism, i.e. glucose turnover, insulin concentration in plasma, insulin clearance, concentrations of non-esterified fatty acids (NEFA), glycerol and potassium were investigated in nine ewes during three reproductive states in order to examine their importance for development of subclinical ketosis. The increase of insulin in plasma was measured after a continuous 60 min intravenous infusion of glucose (4.9 mmol.min-1). Turnover of glucose and insulin clearance were quantified during a combined euglycemic, hyperinsulinemic clamp. Insulin was consecutively infused in doses of 5 and 10 mU.kg-1.min-1 for about 2 1/2 hours, each. Plasma glucose concentration was adjusted to 5.3 to 5.8 mmol.l-1. The experiments were carried out during non-pregnancy and non-lactation, 4 weeks to 3 days before lambing and 3 to 4 weeks after lambing, each during normo- and hypocalcemia. Hypocalcemia (0.9 to 1.0 mmol Ca2+.l-1) was induced by continuous i.v. infusion of a 5% Na-EDTA solution. Infusion rate was continuously adjusted. The glucose induced increase in plasma insulin concentration was significantly lower during late pregnancy compared to peak lactation and non-pregnancy (46.3, 62.4 and 128 mU.l-1, respectively). The insulin clearance during a hyperinsulinemic clamp with 5 mU.kg-1.min-1 was significantly less during late pregnancy compared to peak lactation and non-pregnancy (3.7, 6.0, 4.8 ml.kg-1.min-1, respectively). The concentrations of NEFA and glycerol in plasma during the infusion of 5 mU insulin.kg-1.min-1 were significantly higher during late pregnancy than during non-pregnancy (NEFA: 0.41, 0.04 mmol.l-1; glycerol: 96, 29 mumol.l-1, respectively). The results showed that insulin responsiveness was significantly reduced in sheep during late pregnancy. The insulin-mediated uptake of glucose by muscle and fat tissues and the insulin-mediated inhibition of lipolysis were significantly reduced during late pregnancy compared to non-pregnancy and lactation. The diminished responsiveness of target tissue towards insulin during late pregnancy predisposed the animals for development of subclinical ketosis. Hypocalcemia exaggerated this situation by its inhibitory effect on hepatic gluconeogenesis and by enhancing insulin resistance of target tissues. The factors which are responsible for the altered responsiveness of target tissues towards insulin during late pregnancy are yet unknown. The potassium concentration in plasma showed a proportional increase with increase of the energy deficit of the target tissues. This effect could have been exerted by a decrease in cellular concentration of ATP and a concomitant reduction of the activity of Na(+)-K(+)-ATPase. The indicators of glucose and lipid metabolism which were examined in this study showed marked individual variation, particularly during late pregnancy. The marked changes of these indicators with reproductive stages as well as their great variation between individual sheep support the assumption that they are of significance for the development of pregnancy toxemia in sheep.

Animals↗
PubMed1996

Absorption of short-chain fatty acids across ruminal epithelium of sheep.

Investigations on the absorption of shortchain fatty acids across ruminal epithelium of sheep were performed both in vitro (Ussing chamber technique, using propionic acid representatively for short-chain fatty acids) and in vivo (washed, isolated reticulorumen). A pH-induced, nearly tenfold increase in the concentration of undissociated propionate led to an only twofold increase in mucosal-to-serosal flux of propionate (in vitro). Neither amiloride (1 mmol.l-1, in vitro) nor theophylline (10 mmol.l-1, in vivo), inhibitors of the ruminal Na+/H+ exchanger, exerted any significant influence on propionate fluxes or short-chain fatty acids absorption, respectively. Total replacement of luminal Na+ (by choline) did not alter short-chain fatty acids absorption (in vivo). Mucosal 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (0.1 mmol.l-1) or mucosal nitrate (40 mmol.l-1) markedly reduced propionate net flux (in vitro). Increasing mucosal Cl- concentration brought about a significant drop in mucosal-to-serosal flux of propionate (in vitro) and in short-chain fatty acids net absorption (in vivo), respectively. The results obtained suggest that short-chain fatty acids are absorbed both as anions and as undissociated acids across ruminal epithelium of sheep. It is concluded that short-chain fatty acids anions either compete with Cl- for binding sites at a common anion-exchange mechanism or that they are absorbed by an short-chain fatty acids anion/ HCO3- exchanger indirectly coupled to a Cl-/HCO3- exchanger via intracellular bicarbonate.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1996

[Effect of acute stress on plasma levels of catecholamines and cortisol in addition to metabolites in stress-susceptible growing swine].

The purpose of this study was to show the behaviour of the plasma level of catecholamines in stress-susceptible pigs during an acute stress and to gain new insights in the role of catecholamines in the initiation of malignant hyperthermia. Therefore, a halothane challenge test was performed in stress-susceptible growing pigs, and the changes of haematocrit, hormones and metabolites were monitored during the handling before the test, during halothane exposure and thereafter. Already in connection with the handling before the test, haematocrit values and plasma levels of epinephrine, norepinephrine, glucose, lactate and potassium increased significantly. However, the plasma concentration of cortisol and free glycerol increased gradually and the level of nonesterified fatty acids did not show any changes. While the levels of catecholamines and potassium decreased already during halothane exposure, haematocrit values and concentrations of glucose and lactate continued to increase. The present results indicate that the catecholamines are not involved in the initiation of malignant hyperthermia.

Animals↗
PubMed1995

Selective recovery of Streptosporangium fragile from soil by indirect immunomagnetic capture.

A polyclonal antibody raised to Streptosporangium fragile spores reacted strongly and specifically with the immunizing strain and to a number of related species of Streptosporangium, as determined by dot immunoblotting. An indirect immunomagnetic capture method was developed for the recovery of the target organism from sterile and non-sterile soil, using sheep anti-rabbit M-280 Dynabeads. The effects of different soil blocking agents, antibody labelling concentrations and spore/Dynabead capture times on the recovery of S. fragile spores were investigated. Pre-blocking of antibody binding sites within the soil, with either 2% partially hydrolysed gelatin or 10% skimmed milk, was essential prior to immunomagnetic capture. Increasing the capture time from 15 to 60 min did not affect spore recovery; however, a 10-fold decline in the magnetic bead concentration did result in a significantly lower recovery of spores from soil. S. fragile was selectively enriched (1:190-fold) when present as a mixed population with Arthrobacter oxydans in sterile soil. The indirect immunomagnetic capture method was used to selectively recover S. fragile spores seeded into non-sterile soil, although some background binding of non-target bacteria was noted. The target was successfully recovered from a sterile soil microcosm after 14 d incubation and the capture rate was increased by the inclusion of an initial soil dispersion and biomass concentration procedure, using the ion-exchange resin Chelex 100.

Actinomycetales↗
PubMed1994

Elucidation of the mechanism of CryIIIA overproduction in a mutagenized strain of Bacillus thuringiensis var. tenebrionis.

NB176 is a Bacillus thuringiensis mutant derived by gamma-irradiation of NB125 Bacillus thuringiensis var. tenebrionis (Krieg). It exhibits two interesting phenotypes: (i) oligosporogeny and (ii) twofold to threefold overproduction of the CryIIIA protein. Southern profiles of the NB176 strain showed an additional copy(s) of the cryIIIA gene located on a 4 kb HindIII fragment, in addition to the expected cryIIIA gene on a 3 kb HindIII fragment. Each cryIIIA gene-bearing HindIII fragment was cloned from NB176. The restriction map of the 3 kb HindIII fragment was identical to that published by Donovan and coworkers. Sequencing of the 4 kb HindIII fragment showed no alterations in the promoter region of the cryIIIA gene but did show replacement of the region immediately following the cryIIIA open reading frame with a sequence encoding a transposase with 50% amino acid homology to that of Tn1000. These findings suggest that the overproduction phenotype of NB176 results from extra copies of the cryIIIA gene produced from a transposition event(s) induced or stabilized by gamma-irradiation. Integration of additional copies of the cryIIIA gene into the native 90 MDa plasmid of the wild-type B. thuringiensis var. tenebrionis strain resulted in strains that made enormous crystals, many possessing greatly enhanced insecticidal activity.

Amino Acid Sequence↗
PubMed1994

Albaflavenone, a sesquiterpene ketone with a zizaene skeleton produced by a streptomycete with a new rope morphology.

A novel antibiotic alpha,beta-unsaturated sesquiterpene ketone, albaflavenone with a zizaene skeleton was isolated from a morphologically novel, highly odorous Streptomyces species which was identified with the species group S. albidoflavus, cluster 1. The new compound, partly responsible for the odour, was assigned the structure of 2R',6,7,7-tetramethyl-1S',8R'- tricyclo-[6.2.1.0(1,5)]undec-5-en-4-one based on spectroscopic studies including 2D NMR (COSY, HETCOR, ROESY, NOE-difference) experiments.

Anti-Bacterial Agents↗
PubMed1994

[The effect of anesthesia, of an alpha or beta adrenergic blockade in conscious and of adrenaline in anesthetized halothane-positive swine on hematologic and metabolic parameters in the blood during the course of halothane exposure].

The halothane test was performed under different conditions in 10 halothane-sensitive growing pigs (Landrace, line 01). Haematological and metabolic changes in blood were monitored during the handling of the pigs before the test, during the exposure to halothane and thereafter. Already in connection with the catching and fixation of the pigs, the levels of haemoglobin in blood, and of glucose, lactate and potassium in plasma increased significantly. However, the concentration of glycerol was not raised before the occurrence of the malignant hyperthermia. While the level of potassium decreased already from the beginning of the halothane exposure until the development of symptoms, the values of haemoglobin, glucose and lactate continued to increased. The level of the free fatty acids did not show any changes during the experimental period. An infusion of phentolamine reduced the increase of haemoglobin and potassium and an infusion of propranolol reduced the increase of haemoglobin and glycerol significantly, without any effect on the result of the halothane test. By an anaesthesia, starting 30 minutes before the exposure to halothane, the development of the typical halothane reaction was obviated for at least 10 minutes. Observed metabolic changes during a simultaneous epinephrine administration were exclusively due to its adrenergic effects.

Anesthesia↗
PubMed1993

Acute metabolic and hormonal effects of intravenously administered sodium n-butyrate in untreated and alloxan-diabetic sheep.

Experimental diabetes was induced in 4 wethers of the Mutton Merino breed by intravenous injection of alloxan (75 mg.kg-1) in order to determine its impact on plasma glucose, immunoreactive insulin, free fatty acids (FFA), cholesterol, phospholipids, triglycerides, D-(-)-3-hydroxybutyrate (D-3-HB), bilirubin and aspartate aminotransferase (ASAT) as well as on the changes of these parameters brought about by an intravenous infusion of sodium n-butyrate (1 mmol.kg-1). Alloxan administration caused a significant elevation of plasma glucose, FFA, triglycerides, cholesterol, phospholipids, D-3-HB and bilirubin and a decrease of the level of immunoreactive insulin. The increase in glucose level brought about by a bolus injection of sodium n-butyrate in untreated sheep did not appear in alloxanized animals. Thus, it is suggested that the lack of hyperglycaemic response in diabetic sheep was due to the absence of liver glycogen stores. Unexpectedly in alloxan-diabetic sheep, a decrease in the plasma level of FFA occurred after the administration of sodium n-butyrate. Therefore, it may be assumed that beside insulin other factors may contribute to the decrease of FFA under these conditions.

Alloxan↗
PubMed1992

[Ionized calcium and total calcium in the blood of cattle, sheep, swine and horses of different ages, reproductive stages and uses].

Concentrations of ionized calcium (Cai) in blood and of total calcium (Ca(t)) in serum were determined in 99 cattle, 58 sheep, 74 pigs and 59 horses of different age groups and reproductive periods as well as kinds of use of the animals. The values of Cai in blood in the groups taken into account for comparison of species decreased significantly in the order dairy cows < ewes < sows < horses. In cattle and pigs, there were significant differences in the Cai-level, according to age with the youngest animals having the highest values. In cows from the fourth lactation onward, one day post partum (p.p.) the smallest concentrations were measured, differing significantly from animals in other reproductive periods. In ewes, the lowest values were estimated one week before parturition. The level of Cai in blood of sows decreased between day one and 6 weeks p.p. significantly. No significant differences could be demonstrated between the different groups of horses. With regard to the concentrations of total Ca, differences between the groups were not so clear as with Cai.

Animals↗
PubMed1991

Zygosity, placental membranes and Weinberg's rule in a Danish consecutive twin series.

The usual assumption that monochorionic twins are monozygotic has recently been questioned, based on blood group discordance in 3 of 12 monochorionic pairs. Therefore, this study evaluates the validity of zygosity diagnosis based on examination of placental membranes, and at the same time evaluates Weinberg's differential rule in a Danish consecutive twin series. All twin pairs, 265 like-sexed and 87 unlike-sexed pairs, born at Odense University Hospital, Denmark, from 1 January 1980 through 31 August 1988, were ascertained. In 229 like-sexed pairs, zygosity was determined by serological methods, and in 190 of these, the fetal membranes could be reliably classified. Fifty-nine monochorionic twin pairs were identified and none of those pairs were discordant for any genetic markers. Therefore, we conclude that monochorionic twins can be considered monozygotic. The distribution of monozygotic and dizygotic pairs was in accordance with Weinberg's rule.

Female↗
PubMed1990

A 5 year interdisciplinary control of iodine deficiency in the GDR.

The interdisciplinary iodine prophylaxis in the GDR is a successful measure for control of ID. The iodization of nearly all the salt is planed perhaps with reduction of the iodine concentration. However, next further steps may be done in cooperation of the Interdisciplinary Iodine Commission with the "Arbeitskreis: Jodmangel" in the FRG.

Germany, East↗
PubMed1989

Interdisciplinary aspects of iodine prophylaxis in German Democratic Republic.

Endemic goiter still occurs in several European countries. Alimentary iodine deficiency could be proved as the main cause of endemic prevalence. Extensive epidemiologic surveys showed the great medical and economical impact of this matter for the GDR. Over 200 million Marks might be spent for diagnosis and treatment of thyroid patients per year. Also in the field of veterinary medicine and animal production iodine deficiency plays an important role. Under the conditions of iodine deficiency the fodder containing nitrate and glucosinolates (e.g. bruised rape extraction) results in additional goitrogenic effects (so-called indirect or relative iodine deficiency). Due to iodine deficiency disorders considerable losses of yields in cattle, pigs and sheep occurred. The content of iodine in animal products used for human nutrition was subsequently low. Considering the ecological implication of these problems an Interdisciplinary Iodine Commission within the Society for Endocrinology and Diseases of Metabolism of the GDR was established. Together with the governement authorities it worked out corresponding recommendations for the prophylaxis and control of its efficiency. In 1986 the iodination of most of the packed salt (32 mg KIO3/kg = = 19 mg I/kg) and the administration of iodinated mineral mixtures for the animal production were started for pigs in the whole territory of GDR and for cattle in the southern counties of the GDR only. These activities have been accompanied by information of TV as well as in the newspapers and medical journals. Thus, an improved supply of iodine to the population through iodinated table salt and animal products can be taken into account. The efficiency of these prophylactic measures is controlled interdisciplinarily.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Husbandry↗
PubMed1988

HLA and hydatidiform mole. I. HLA and ABO antigen frequencies in couples with androgenetic and diandric conceptuses.

HLA and ABO antigen frequencies and mating rates were studied in couples with hydatidiform mole with known genomic origin. HLA-A,B antigen frequencies among 60 patients and 59 spouses were not different from those found in the background population, neither in the subgroups regarded alone nor in the entire series. Although not significant, an excess of HLA-DRw6 found in patients with androgenetic conceptions may be related to the anucleate ovi observed with androgenesis. The distribution of ABO blood groups was in accordance with that observed in the background population; however, an overall excess of A x O matings was found.

ABO Blood-Group System↗