Microbiological and enzymatic properties of soil deposits originating from wind erosion

A characterization of deposits originating from wind erosion of agriculturally managed soils in eastern Austria with the main soil types Chernozems and Allochthonous Calcaric Fluvisols was conducted using measurements of microbial counts, soil respiration, soil microbial biomass, and several enzyme activities. The deposits were rich in organic matter, silt‐ and clay‐sized mineral particles, and had high water‐holding and cation exchange capacities. Microbial counts, biomass, and enzyme activities of the deposits covered ranges frequently reported for agriculturally managed soils. Metabolic quotients indicated reduced energetic efficiences of deposit associated microbial communities. Microorganisms might suffer from stress imposed by habitat destruction, drifting, and unfavorable physical conditions in the deposits. Shifts in microbial communities or properties of organic materials in the deposits might also result in high metabolic quotients. It will be the subject of further study to clarify causal relationships.     

The influence of rock powders on microbial activity of three forest soils

To improve the quality of forest soils by applying basic rock powders tests were carried out in Vorarlberg (Austria) in 1987: in the vicinity of Möggers on Stagno-Mollic Gleysol under Abieti-Fagetum luzuletosum, in Nenzing on Calcaric Regosol and Cambisol under Abieti-Fagetum luzuletosum and in Montafon on Stagno-Dystric Gleysol under Homogyno-Piceetum. The effects of a low dosage of rock powder application on nitrification, basal respiration, microbial biomass, xylanase, phosphatase and protease activities, the amount of nitrate nitrogen (NO₃^?-N), and the soil pH were investigated. Additions of rock powder increased protease, NO₃^?-N content and pH, but decreased phosphatase in the A_h-horizon of the Stagno-Mollic Gleysol. After 3 years the A_h-horizon from the experimental site Nenzing showed statistically verified differences of all investigated parameters except xylanase. In the acid spruce forest soils of the Montafon site the rock powder had no statistically significant effect on microbiological parameters. Only the soil pH increased. It can be postulated that the application of rock powders furthered C- and N-mineralization. In the long run this affects the turnover of mineral nutrients in forest ecosystems.     

Phosphomonoesterase,phosphodiesterase, phosphotriesterase,and inorganic pyrophosphatase activities in forest soils in an alpine area: effect of pH on enzyme activity and extractability

We investigated different types of phosphatase activity (phosphomono-, phosphodi-, phosphotriesterase, inorganic pyrophosphatase) in five forest soils in Vorarlberg, Austria. Phosphatase activity was determined both in soils and in soil extracts prepared with different solutions (distilled water, 0.1M sodium pyrophosphate at pH 7, 0.1M sodium phosphate buffer/1M KCl at pH 6.5, and a modified universal buffer at pH 4, 6.5, 9, and 11). High phosphomonoesterase activity in these soils indicated a severe deficiency in available P. Acidic phosphomonoesterase prevailed over alkaline phosphomonoesterase activity. Phosphodiesterase was highest in the least acidic soil but no general trend towards an optimum pH was recognized. Phosphotriesterase activity was observed in only two of the five soils and favoured an alkaline optimum pH; this activity was not detected in strongly acid soils. Inorganic pyrophosphatase activity was high in soils with no phosphotriesterase. Phosphomonoesterase, phosphodiesterase and inorganic pyrophosphatase activities were much lower in soil extracts than in soils.     

A family with severe insulin resistance and diabetes due to a mutation in AKT2

Inherited defects in signaling pathways downstream of the insulin receptor have long been suggested to contribute to human type 2 diabetes mellitus. Here we describe a mutation in the gene encoding the protein kinase AKT2/PKBbeta in a family that shows autosomal dominant inheritance of severe insulin resistance and diabetes mellitus. Expression of the mutant kinase in cultured cells disrupted insulin signaling to metabolic end points and inhibited the function of coexpressed, wild-type AKT. These findings demonstrate the central importance of AKT signaling to insulin sensitivity in humans.     

Aminosäurenbildung durch Mikroorganismen aus der Rhizosphäre der Zirbe (Pinus cembra L.)

Zusammenfassung Mit der vorliegenden Arbeit wurde erstmals die freie Aminos?urenbildung durch Rhizosph?renmikroorganismen mykotropher Forstpflanzen untersucht. Getestet wurden eine Pseudomonade (Stamm 51) und die HefeCryptococcus albidus (Saito) Skinner var.albidus (Stamm 8) über eine begrenzte Kulturdauer in einem Medium mit Ammoniumchlorid als einziger Stickstoffquelle. Die Dünnschichtchromatographie der Aminos?uren aus den Kulturflüssigkeiten brachte nach vorhergehender Aufbereitung überdurchschnittliche Ergebnisse. Es gelang, für die Pseudomonade 25 freie Aminos?uren nachzuweisen, wobei Alanin, Valin, Leucin-Isoleucin und Lysin vorherrschen. Für die Hefe wurden 15 Aminos?uren nachgewiesen, wobei Alanin und Leucin-Isoleucin dominierten. Die Aminos?urenproduktion der Hefe war unter gegebenen Bedingungen merklich geringer als die der Pseudomonade.

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Production of amino acids by rhizosphere-microorganisms of Pinus cembra L.

Summary The production of free amino acids by rhizosphere-microorganisms of mycotrophic forest plants were investigated for the first time. For a limited time of cultivation in a medium containing ammoniumchloride as the only nitrogen-source a Pseudomonade (strain 51) and the yeastCryptococcus albidus (Saito) Skinner var.albidus (strain 8) were tested. The thinlayer chromatography of amino acids from cultivation liquid yields better results after previous processing. The formation of twenty-five amino acids was demonstrated for the Pseudomonade, where alanine, valine, leucine-isoleucine and lysine prevailed. Fifteen amino acids could be detected in cultures of the yeast, where alanine and leucine-isoleucine dominated. The production of the amino acids by the yeast was distinctly less than that of the Pseudomonade.

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Die vorliegende Arbeit ist ein Teil einer Dissertation, ausgeführt an der Universit?t Innsbruck unter der Betreuung von Prof. Dr.M. Moser.     

Association of A31P and A74T Polymorphisms in the Myosin Binding Protein C3 Gene and Hypertrophic Cardiomyopathy in Maine Coon and Other Breed Cats

Background: Hypertrophic cardiomyopathy (HCM) is an inherited autosomal dominant trait in cats. The A31P single nucleotide polymorphism (SNP) in the myosin binding protein C 3 gene is thought to be the causative mutation in Maine Coon cats. Additionally, the A74T SNP is offered as a genetic test for HCM. Objectives: To evaluate the genetic association between the above‐mentioned SNPs and phenotypes. Animals: Eighty‐three Maine Coon cats and 68 cats of other breeds. Methods: The study was performed prospectively. Cats were phenotyped as healthy or HCM with echocardiography. Taqman genotyping assays were used for genotyping; results were confirmed by sequencing analysis. Results: A31P was found in 18/83 (22%) Maine Coon cats. Fifteen of 18 Maine Coons (83%) with the A31P mutation were healthy on echocardiographic examination (mean age 65 months). A74T was present in 28/79 (35%) of Maine Coons and in 42/68 (62%) of other cat breeds. Twenty‐two of 28 (79%) of Maine Coons and 21/42 (62%) of other breed cats with the A74T mutation were healthy at a mean age of 72 months and 91 months, respectively. Of 12 Maine Coons with HCM, 9 (75%) were genotype‐negative for A31P and 6 (50%) for A74T. Allele frequencies did not differ significantly (P= .47) between phenotype groups. None of the evaluated genetic tests was able to provide useful predictive information of disease outcome. Conclusions and Clinical Importance: The value of currently available genetic tests is low in the cats of this study. The mutations analyzed appear to have a low penetrance, and even homozygote cats can remain healthy.     

Der Einfluß von Fungiziden auf die mikrobielle Aktivität eines Bodens

The influence of fungicides on microbial activity in soil The objective of this work was to investigate the influence of the fungicides copper, sulfur, mancozeb, captan-folpet-folcid, quintozene and benomyl on CO₂-evolution and on the dehydrogenase-, xylanase- and urease-acitivities of an acid soil. The investigations showed that a recommended dosage of fungicide caused an increase in CO₂-evolution. After the second and third fungicide application this ‘stress reaction’ was followed by a decrease in CO₂-release below the value of the untreated control soil. Up to the tenth week after pesticide application again an increase of the activity could be shown. This increase might be explained by an inactivation of fungicides, a selection of resistant species, a decreasing competition of microorganisms and mineralization of dead organisms. Finally, after 10 to 14 weeks the activity returned to the value of the untreated soil, that was probably due to the recovery of the affected microflora and/or a new adapted microflora. The various enzyme activities did not follow this scheme exactly. The course was influenced by the mode of action of the particular compound used. Brassicol (Quintozene) differed because of the severe and continous inhibition of the xylanase activity. It can be concluded that the fungicides applied to the soil influence both the CO₂-release and the activities of the soil enzymes tested. Consequently litter decomposition and metabolic activities may be affected for 3 to 4 months.     

An improved and accurate method for determining the dehydrogenase activity of soils with iodonitrotetrazolium chloride

Summary Conditions for a rapid, precise [100 g iodonitrotetrazolium chloride (INT)-formazan ml^-1 assay mixture], and easily reproducible assay of potential soil dehydrogenase activity are described, using 2(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chloride (iodonitrotetrazolium chloride, INT) as the substrate. Reduced iodonitrotetrazolium formazan (INTF) was measured by spectrophotometry (464 nm) after extraction with N,N-dimethylformamide and ethanol. With this method, the coloured complex formed is highly stable. The effects of pH, buffer concentration, temperature, substrate concentration, amount of soil weight, and reaction time on dehydrogenase activity were investigated. The rate of substrate hydrolysis was proportional to soil weight; the optimal INT reduction was achieved with 1 M TRIS buffer (pH 7.0) at 40 °C. It was possible to determine the biotic and abiotic substrate reduction by comparing assays of autoclaved and unsterile soil samples. Different investigations have confirmed that the intracellular enzyme is highly correlated with the microbial biomass, and indicate that this activity is suitable as an indirect parameter of microbial biomass, measurement.     

Buchbesprechung

Bodenbiologische Arbeitsmethoden

2., überarb. u. erw. Aufl. 1993. XVI, 390 S. 20 Abb. (Springer Labor) Geb. DM 78, ISBN 3–540–56206–0 Springer Verlag Berlin Heidelberg New York