Temperature-sensitive genes for resistance to Puccinia striiformis in Triticum dicoccoides

Summary Twenty-six selections of wild emmer collected at different sites in Israel and three entries obtained from Turkey were studied for the possible presence of temperature-sensitive genes controlling reaction to Puccinia striiformis. In tests carried out in Israel with a local P. striiformis isolate at two temperature regimes, 16 selections showed a change in infection rating toward resistance at the higher temperature regime. In comparable tests performed in the United States with a Montana P. striiformis isolate of different virulence pattern-including 14 of the same selection—ten entries displayed a temperature-sensitive reaction. Although slightly different temperature regimes were used in Israel and the United States, the results obtained were in general agreement. The shift toward resistance observed in the seedling tests at the higher temperature-profile was also evident in the field in the mature plant stage with increasing spring temperatures.     

Validierung eines 2-Regionen-Modells zur Simulation des Stofftransportes im Boden anhand von Laborsäulen- und Feldversuchen

Validation of a 2-domain-model for the simulation of solute transfer in soils by laboratory and field experiments The simulation of water and solute transfer in the unsaturated zone on the basis of the classical convective dispersive model gives dissatisfactory results in many cases. Especially in the zone of evapotranspiration the observed penetration depths of surface-applied chemicals often exceed calculated values. This has been attributed to preferential flow in domains with accelerated flow. The aim of the investigations presented here was to extend the conventional theory of solute transfer in order to enable improved model predictions without introducing too much complexity to the model which might reduce its applicability. The mobile-immobile-concept of Coats and Smith (1964) was chosen to extend the model FLOTRA (Wagner et al., 1992), which is based on the convective dispersive approach. The model parameters additionally needed by the model are the immobile water content θ_im and the solute transfer coefficient α. The applicability of the model was tested on the basis of several laboratory and field experiments. It is shown, that with the mobile-immobile-approach modeling results of water and solute transfer in the top soil layers, which are most important in view of soil and groundwater protection, were improved compared to the calculations with the classical convective dispersive model.     

Accumulation soils like “Ockererde”—forgotten soil units in soil‐classification systems

Accumulation soils like those known as “Ockererde” are not yet represented in the German and in international soil‐classification systems, even though they represent important members of catenas found in humid low‐mountain areas influenced by the translocation of interpedon matter. Currently, this soil is referred to as “(Hang‐)Oxigley”, though this does not take into account its water and matter dynamics. Six representative catenas in the Black Forest (SW Germany) will be used to describe the occurrence, extent, and properties of the accumulation‐affected “Ockererde” derived from a variety of parent materials at specific altitudes. On the basis of their morphological, chemical, and physical properties as well as matter dynamics, it is possible to distinguish “Ockererde” clearly from soil units with similar characteristics (“Lockerbraunerde”, Andosols). Finally, suggestions will be given for the classification of “Ockererde”.     

Effects of heating and illumination on trans-cis isomerization and degradation of beta-carotene and lutein in isolated spinach chloroplasts

The influence of thermal treatment and light exposure on degradation and isomerization of the predominant carotenoids (lutein and beta-carotene) occurring in green leafy vegetables was assessed. The effect of lipid addition on carotenoid stability was also evaluated. For the first time, the stabilities of pure carotenoids and chloroplast-bound carotenoids were compared. Besides degradation, heating caused carotenoid isomerization in all samples. Whereas pure carotenoids favor 13-cis isomers, in native chloroplasts and heated chloroplasts 9-cis isomers were predominant. Illumination of freshly prepared chloroplast isolates caused an initial increase in the level of lutein (9.6%) and beta-carotene (29.8%), while pure carotenoids exhibited time-dependent degradation. The addition of lipids to chloroplast preparations had the reverse effects on the retention of both carotenoids after heating; isomerization was not significantly affected. It was demonstrated that carotenoid stability has to be evaluated for every individual pigment in its genuine environment. Stability data based on model systems (e.g., pure carotenoids) may not be transferred to complex food matrices without intensive investigation.     

Determination of carotenoid stereoisomers in commercial dietary supplements by high-performance liquid chromatography

A method for the determination of beta-carotene, lutein, and zeaxanthin including their cis-isomers and alpha-carotene in commercial dietary supplements by HPLC has been developed. The study comprises 11 oral dosage forms, including 9 soft gelatin capsules, 1 dragée, and 1 effervescent tablet formulation. The capsule content was extracted with an acetone-hexane mixture, and the gelatin shell was digested with papain to release carotenoids that had migrated into the coat. Sample preparation for tablets and dragées was carried out as described for the capsule content. Extraction recoveries exemplified for all-trans-beta-carotene and all-trans-lutein were 95 +/- 5% and 93 +/- 2%, and 95 +/- 2% and 79 +/- 5% after enzymatic treatment, respectively. Apart from all-trans-beta-carotene, its 9-cis- and 13-cis-isomers were detected in all samples, whereas no evidence for cis-isomerization of lutein and zeaxanthin could be obtained. Migration of carotenoids into the shells was only observed in the case of beta-carotene. With the exception of one preparation, the beta-carotene contents determined exceeded the dosage specified on the label by up to 48%, which results from stability overages necessary to compensate for losses during storage.     

Methodical studies of transmucosal oxygen partial pressure measurement in the calf and dog]

Transcutaneous PO2-measurement has been thought being non practicable in veterinary medicine. Consequently, the measuring method has been slightly modified. PO2 was taken from the mucous membrane of the lower surface of tongue. This has been practised in 6 dogs and 10 calves. We achieved a significant correlation between transmucosal and arterial PO2, taken simultaneously in each animal. Considering these results the use of transmucosal measurement may be recommended for a trend-measuring in anesthesized animals. Nevertheless, there has to be pointed out that transmucosal PO2 has to be interpreted regarding its complexity.     

Microbial biomass and respiration in soils derived from lignite ashes: a profile study

Microbial biomass C and soil respiration measurements were made in 17–20 yr old soils developed on sluiced and tipped coal‐combustion ashes. Topsoil (0–30 cm) and subsoil (30–100 cm) samples were collected from three soil profiles at two abandoned disposal sites located in the city area of Halle, Saxony‐Anhalt. Selected soil physical (bulk density and texture) and chemical (pH, organic C, total N, CEC, plant available K and P, and total Cd and Cu) properties were measured. pH values were significantly lower while organic C and total N contents and the C : N ratio were significantly higher in the topsoil than in the subsoil indicating the effects of substrate weathering and pedogenic C accumulation. Likewise, microbial biomass C, K₂SO₄‐extractable C, and soil respiration with median values of 786 μg biomass C g^–1, 262 μg K₂SO₄‐C g^–1, and 6.05 μg CO₂‐C g^–1 h^–1, respectively, were significantly higher in the topsoil than in the subsoil. However, no significant difference was observed in metabolic quotient between the topsoil and the subsoil. Metabolic quotient with median values of 5.98 and 8.54 mg CO₂‐C (g biomass C)^–1 h^–1 for the 0–30 cm and 30–100 cm depths, respectively, was higher than the data reported in the literature for arable and forest soils. Microbial biomass C correlated significantly with extractable C but no relationship was observed between it and total N, Cd, and Cu contents, as well as plant‐available K and P. We conclude that the presence of the remarkable concentration of extractable C in the weathered lignite ashes allowed the establishment of microbial populations with high biomass. The high metabolic quotients observed might be attributed to the heavy‐metal contamination and to the microbial communities specific to ash soils.     

Das mineralinventar der versuchsfla¨che "statischer dauerdu¨ngungsversuch v120, bad lauchsta¨dt"

Der Statische Dauerdüngungsversuch Bad Lauchstädt ist einer der wenigen Schlüsselstandorte von internationalem Ruf innerhalb der Erforschung des Umsatzverhaltens organischer Bodensubstanz. Im Rahmen des Schwerpunktprogramms 1090 der DFG "Böden als Quelle und Senke für CO 2 --Mechanismen und Regulation der Stabilisierung organischer Substanz in Böden" wurde die Versuchsfläche als ein Referenzstandort ausgewählt. Die Interaktion von Bodenmineralen mit organischer Bodensubstanz könnte einer dieser Stabilisierungsprozesse sein, aber die bisher vorliegenden Informationen über den Mineralbestand der Versuchsfläche sind unvollständig und widersprüchlich. Um diese Mängel auszuräumen, haben wir den Mineralbestand einer 98 Jahre ungedüngten Variante ("18") und einer kontinuierlich gedüngten Variante ("1") bestimmt. Je Variante wurden 4 Unterproben aus Teilparzellen entnommen, um die flächige Heterogenität des Mineralkörpers zu prüfen. Neben Grunduntersuchungen (Texturanalyse, Bestimmung des pH-Wertes und der potentiellen Kationenaustauschkapazität [KAK pot ]) haben wir zur Kennzeichnung des Mineralbestandes die Röntgendiffraktometrieanalyse (XRD), die Röntgenfluoreszenzanalyse (XRF) und Gehaltsbestimmungen an pedogenen Oxiden durchgeführt. Für die Textur wurden signifikante (p<0.05) Differenzen festgestellt. Der Boden von Variante "18" enthielt 4% mehr Sand als jener von Variante "1", während der Schluffgehalt von Variante "18" um 3% kleiner war als in Variante "1". Weder der Mineralbestand, noch pH-Wert und KAK pot liefern für beide Varianten signifikant verschiedene Ergebnisse. Die Feinerde (<2 mm) beider Varianten enthält ca. 80% Quarz, 14% Feldspäte und 6% Glimmer/Illit. Der Mineralkörper der Tonfraktion (<2 µm) besteht zu ca. 77% aus Illit. Daneben sind Quarz (11%), Kaolinit (6%) und primärer Chlorit (6%) vorhanden. Aufweitbare Dreischichtsilikate wurden nicht nachgewiesen. Die Ergebnisse der Elementgehalte zeigen sehr geringe, aber zum Teil signifikante Unterschiede zwischen Variante "18" und Variante "1". Verschiedenen Publikationen zufolge führt langjährige K-Verarmung zur Transformation von Illiten zu aufweitbaren Dreischichtsilikaten. Keine von uns untersuchte Variante zeigte Anzeichen einer solchen Veränderung. Das Ausbleiben dieser Veränderungen wird von uns auf die K-Düngungspraxis der letzten 30 Jahre oder atmogene K-Einträge aus einem benachbarten Zementwerk zurückgeführt.     

Respiratory chlamydial infection based on experimental aerosol challenge of pigs with Chlamydia suis

An experimental study of aerogeneous challenge in pigs was conducted in order to reveal characteristic features of porcine respiratory chlamydiosis. Eight conventionally raised pigs were exposed to a pathogenic strain of Chlamydia (C.) suis, four controls were mock infected. Besides pathological changes, the acute-phase and humoral immune responses, as well as the dissemination and transmission of the challenge strain was monitored in the course of infection. The data from clinical investigations, LPS-binding protein assay, antibody ELISAs, confocal laser scanning and light microscopy, immunohistochemical staining and PCR provided extensive evidence of the pathogenic potential of C. suis for the porcine respiratory system. This model appears suitable for further pathophysiological and immunological investigations of chlamydial respiratory infections and can also be recommended for studies of Chlamydia-associated infections of the human lung.