Plant breeding: importance of plant secondary metabolites for protection against pathogens and herbivores

Summary Chemical protection plays a decisive role in the resistance of plants against pathogens and herbivores. The so-called secondary metabolites, which are a characteristic feature of plants, are especially important and can protect plants against a wide variety of microorganisms (viruses, bacteria, fungi) and herbivores (arthropods, vertebrates). As is the situation with all defense systems of plants and animals, a few specialized pathogens have evolved in plants and have overcome the chemical defense barrier. Furthermore, they are often attracted by a given plant toxin. During domestication of our crop and food plants secondary metabolites have sometimes been eliminated. Taking lupins as an example, it is illustrated that quinolizidine alkaloids are important as chemical defense compounds and that the alkaloid-free varieties (sweet lupins), which have been selected by plant breeders, are highly susceptible to a wide range of herbivores to which the alkaloid-rich wild types were resistant. The potential of secondary metabolites for plant breeding and agriculture is discussed.     

Induction of unscheduled DNA synthesis and micronucleus formation in Syrian hamster embryo fibroblasts treated with cysteine S-conjugates of chlorinated hydrocarbons

S-(chloroethyl)-cysteine (CEC) and S-(1,2-dichlorovinyl)cysteine (DCVO) have been proposed as intermediates in the metabolic transformation of the carcinogens 1,2-dichloroethane and 1,1,2-trichloroethylene. We have tested the ability of CEC and DCVC to induce DNA repair and genotoxic effects at the chromosomal level by comparative assessment of unscheduled DNA synthesis induction and micronucleus formation in Syrian hamster embryo fibroblasts. CEC induced a potent and dose-dependent response in both assays, whereas DCVC treatment resulted in a comparatively weak induction of DNA repair and failed to raise micronucleus formation above control rates. Inhibition of cysteine conjugate \gB-lyase diminished the effect of DCVC, but had no influence on the genotoxicity of CEC either in the unscheduled DNA synthesis or micronucleus assay.Abbreviations AOAA aminooxyacetic acid - CEC S-(chloroethyl)-cysteine; \gB-lyase, cysteine conjugate -lyase - DCE 1,2-dichloroethane - DCVC S(1,2-dichlorovinyl)-cysteine - GSH glutathione - HU hydroxyurea - IBR IBR-modified Dulbecco's Eagle's reinforced medium - MN2 micronuclei/2,000 cells - 4-NQO 4-nitroquinoline-1-oxide - SHE Syrian hamster embryo fibroblasts; ³H-Thd, ³H-thymidine - TCE 1,1,2-trichloroethylene - UDS unscheduled DNA synthesis     

Cancer: improving early detection and prevention. A community practice randomised trial.

OBJECTIVE--To test the impact of physician education and facilitator assisted office system interventions on cancer early detection and preventive services. DESIGN--A randomised trial of two interventions alone and in combination. SETTING AND SUBJECTS--Physicians in 98 ambulatory care practices in the United States. INTERVENTIONS--The education intervention consisted of a day long physician meeting directed at improving knowledge, attitudes, and skills relevant to cancer prevention and early detection. The office system intervention consisted of assistance from a project facilitator in establishing routines for providing needed services. These routines included division of responsibilities for providing services among physicians and their staff and the use of medical record flow sheets. MAIN OUTCOME MEASURES--The proportions of patients provided the cancer prevention and early detection services indicated annually according to the US National Cancer Institute. RESULTS--Based on cross sectional patient surveys, the office system intervention was associated with an increase in mammography, the recommendation to do breast self examination, clinical breast examination, faecal occult blood testing, advice to quit smoking, and the recommendation to decrease dietary fat. Education was associated only with an increase in mammography. Record review for a patient cohort confirmed cross sectional survey findings regarding the office system for mammography and faecal occult blood testing. CONCLUSION--Community practices assisted by a facilitator in the development and implementation of an office system can substantially improve provision of cancer early detection and preventive services.     

Ferritin enhances production of DNA strand breaks by 6-hydroxydopamine,ascorbic acid and H2O2 in CCC PM2 bacteriophage DNA

Damage of CCC PM2 DNA by 6-hydroxydopamine (6-OHDA) and ascorbic acid (AA), compounds that are both able to release iron from ferritin, was significantly enhanced in the presence of ferritin. H₂O₂, a product of 6-OHDA autoxidation, did not induce DNA strand breaks in the absence of ferritin and only to a minor extent in the presence of ferritin. DNA damage by 6-OHDA and AA could be reduced by the hydroxyl radical scavenger mannitol, the iron chelator desferrioxamine, and, partly, by a combination of superoxide dismutase and catalase. These inhibitory effects were clearly less pronounced in the presence of ferritin. Ferritin obviously played an important role as a source of iron in the pro-oxidative processes of 6-OHDA and AA. These features might be of importance in cancer therapy since many tumor cells contain elevated ferritin levels.     

Retino-fugal projections in congenitally monophthalmic fish and anurans

Summary Intra-ocular deposition of horseradish peroxidase was used to visualize optic tract projections in normal and congenitally monophthalmic catfish and Xenopus. In neither species was evidence for an increased ipsilateral visual component found in congenitally one-eyed specimens. This indicates that competition between axons from both eyes is not an important mechanism for fiber distribution in the chiasm during ontogeny. Furthermore, it suggests that enhanced ipsilateral components, previously noted in unilaterally enucleated fish and anurans, are caused by debris of degenerated axons.     

The influence of hypotonic treatment on the morphology of meiotic stages II. Prophase of the first meiotic division of female mice up to dictyotene

The copy number of the mdg-1 mobile element was determined by biotinylated-DNA hybridization, in salivary gland chromosomes of inbred Drosophila melanogaster larvae from sib progenies. It appears that the lower the egg-to-adult survival (viability), the higher the mdg-1 copy number in the surviving larvae. This suggests a common regulation of the mdg-1 copy number and the viability under inbreeding.     

Die Bestandsentwicklung von Kleinv?geln in Mitteleuropa: Analyse von Fangzahlen

Zusammenfassung Im Mettnau-Reit-Illmitz-Programm (MRI-Programm) der Vogelwarte Radolfzell wurden von 1974–1983 auf drei Fangstationen in Süddeutschland, Norddeutschland und Ostösterreich (Abb. 1) 184 939 Vögel von 37 Kleinvogelarten gefangen. Die Fänge erfolgten jährlich während der gesamten Wegzugperiode von Ende Juni bis Anfang November an Durchzüglern in Japannetzen unter strikter und umfassender Standardisierung aller Fang- und Arbeitsmethoden. Die Fangzahlen (Tab. 1, Abb. 2–6) werden in fünf Regressionsanalysen (Tab. 2–9) auf systematische Änderungen untersucht.Von insgesamt 496 errechenbaren Koeffizienten waren 317 oder 63,9% negativ und nur 179 oder 38,1 % positiv. Bei 34 der 37 untersuchten Arten ließen sich signifikante Trends errechnen. Sie sind für 20 oder 54 % dieser Arten ausschließlich oder überwiegend negativ. 14 Arten zeigten mindestens auf zwei Stationen negative Trends. Nur für insgesamt 10 Arten ließen sich überwiegend positive Trends errechnen. Faßt man negative Trends und Tendenzen (Vorzeichen) zusammen, so ergibt sich für 26 oder 70 % der untersuchten Arten ein negatives Bild. Dieses stark negative Gewicht ist im statistischen Sinne keine zufällige Erscheinung. Da die Bestandszunahmen die Abnahmen nicht aufwiegen konnten, zeigten auch die jährlichen Gesamtfangzahlen aller drei Stationen negative Trends. Die mittlere jährliche Abnahme betrug auf den Stationen Mettnau, Reit und Illmitz etwa 1,6 %. Die Tendenzen und Trends der einzelnen Arten stimmen auf den drei Stationen weitgehend überein. Sie lassen für ihr Zustandekommen auf weitgehend gleichförmige Ursachen bei den durch Mitteleuropa wandernden Populationen schließen.Die Fangzahlen und Literaturdaten zeigen, daß beträchtliche Teile unserer Kleinvogelwelt von Rückgangserscheinungen betroffen sind, wie wir sie von vielen Großvogelarten seit langem kennen. Bei einer Reihe von Arten sind die Abnahmen gravierend und die jährlichen Fangzahlen inzwischen so niedrig, daß sich bei ihnen mit den in den 70er Jahren konzipierten Fanganlagen eine Reihe von Fragestellungen nicht mehr untersuchen lassen. Wir können der weiteren Entwicklung der Bestände unserer derzeit noch artenreichen Kleinvogelwelt — wie der vieler Großvögel — nur mit größter Sorge entgegensehen. Die Ursachen der Rückgänge sind weitgehend unbekannt, und demzufolge mangelt es fast vollständig an geeigneten Gegenmaßnahmen. Bisherige Schutzmaßnahmen haben die Rückgänge nicht aufhalten können. Künftiger Vogelschutz wird sich folglich weitergehender Maßnahmen bedienen müssen.

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The development of songbird populations in central Europe: Analysis of trapping data

Summary In the Mettnau-Reit-Illmitz-Program (MRI-Program) of the Vogelwarte Radolfzell 184 939 birds of 37 songbird species were caught in the period 1974–1983 on three trapping stations in S. and N. Germany and E. Austria (Fig. 1). Trapping of passage migrants in mist nets occurred annually from the end of June to the beginning of November, the entire autumn migratory period. All trapping and working methods were strictly and comprehensively standardized. The trapping figures (Tab. 1, Fig. 2–6) were analyzed with respect to systematic alterations to gain information about changes in the population levels of species migrating through central Europe. The investigation is based above all on five regression analyses (Tab. 2–9).The most important individual results are: out of a total of 496 coefficients which could be calculated 317 or 63.9 % were negative and only 179 or 38.1 % positive. For 34 of the 37 investigated species significant trends could be calculated. In 20 or 54 % of these species they were (exclusively or predominately) negative. 14 species showed negative trends at least at two stations. Mainly positive trends could be found in only 10 species. Taking negative trends and tendencies (negative signs) together, 26 or 70 % of the species were included. This strongly negative bias is not accidental in a statistical sense. Since the increases could not balance the declines, the annual trapping totals of all three stations also showed negative trends. The mean annual decline in the stations Mettnau, Reit and Illmitz was about 1.6 %. Trends and tendencies of the species show a high degree of agreement for the three stations. This suggests that in the species migrating through central Europe rather uniform factors control the population levels. From the most recent literature results, it appears that most of the species with declining trapping figures in the MRI-Program demonstrate decreases elsewhere.The trapping figures of the MRI-Program and data from the literature together clearly indicate that considerable parts of our small birds are affected by declines as have been known in many large bird species for long time. In a number of species the decreases have been quite dramatic and their annual trapping totals are now so low that a number of problems can no longer be studied. We should be alarmed when considering this negative development among our small birds as we must be with respect to many large bird species. The reasons for the declines are almost unkown and thus there is lack of appropriate counter-measures. Hitherto existing efforts for conservation which are briefly discussed have not been able to prevent the decline. Consequently, bird conservation in the future has to be based on more effective methods. Proposals, briefly raised, will be discussed in a forthcoming paper.

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Mit Unterstützung der Deutschen Forschungsgemeinschaft und gefördert mit Hilfe von Forschungsmitteln des Landes Niedersachsen. 15. Mitteilung aus dem MRI-Programm     

Habitatwahl beim Neunt?terLanius collurio

Zusammenfassung Im Bereich des Meßtischblattes Bad Wildungen (MTB 4820; grundlegende DatenMann 1983,Lübcke &Mann 1984) bevorzugt der Neuntöter Viehweiden (Abb. 3). Reviere an Viehweiden zeigen eine längere kontinuierliche Besetzungszeit (Abb. 4) im Vergleich zu anderen Nutzungsformen. Die Anzahl flügger Jungvögel ist in Viehweiderevieren größer im Gegensatz zu Revieren an Mähwiesen oder Brachflächen (Abb. 5). Dieser Unterschied des Reproduktionserfolges liegt nicht an unterschiedlichen Nahrungsdichten (Abb. 6), sondern an der besseren Zugänglichkeit.

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Habitat selection in the Red-backed ShrikeLanius collurio

Summary In the area of Bad Wildungen (FRG; Hessia; MTB 4820; basic data inMann 1983,Lübcke &Mann 1984) the Red-backed Shrike selects for pastures (Abb. 3). Territories at pastures show a longer continual occupation in comparison to other land use systems (Abb. 4). The number of fledgelings is higher at pastures in comparison to meadows or fallow land (Abb. 5). This difference is not caused by higher insect densities (Abb. 6) but by better accessible prey due to permanent low vegetation at pastures.

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Reihenfolge alphabetisch und umgekehrt proportional zur geleisteten Arbeit: R. B. Auswertung, W. L. & W. M. Kartierung, W. M. Brut- und Nahrungsbiologie. Sonderdruckanforderungen an R. B.     

Nachweise von Zweitbruten beim Wei?sternigen Blaukehlchen (Luscinia svecica cyanecula)

Summary Close to the village Trieb in Upper Franconia (50° 09 N/11° 10 E) two cases of second breeding in the Bluethroat could be proved. The birds were colour-banded. Second broods are presumably rather common in the population along the upper River Main.