Iron and transferrin in acute experimental Salmonella cholerae-suis infection in pigs

The effects of experimental Salmonella cholerae-suis inoculation with a virulent and an avirulent strain on serum iron (SI), total iron-binding capacity (TIBC), and transferrin (TF) were evaluated. Inoculation of virulent strain 38 was followed by significant (P less than 0.05) decreases of SI, TIBC, and TF. Exposure to avirulent strain 33 was followed by moderate decreases of SI, TIBC, and TF. When exposure to avirulent strain 33 was followed by challenge exposure with virulent strain 38, the SI, TIBC, and TF values remained at initial values or were higher. Negative correlation was observed between rectal temperature and SI and TIBC values, but was significant (P less than 0.0001) only 7 days after inoculation of the virulent strain 38.     

Biotechnische Regulierung der Kohlmottenschildlaus in Kohlgem��se �C Sachstand und Perspektiven

The cabbage whitefly,Aleyrodes proletella, has developed to a key pest in brassica vegetable crops throughout Germany. In a 3-year project we investigated a biotechnical approach employing netting (0.8?×?0.8 mm meshsize) in combination with the native parasitoidEncarsia tricolor in an inoculative-inundative approach in organic Brussels sprouts under field conditions. In small scale plot experiments continuous netting from transplanting in May till October alone reduced whitefly larval densities by 77 % at peak infestation in all years. Remaining whitefly infestation under net was associated with the necessity of temporary net removal for the purpose of mechanical weeding, which caused primary whitefly infestation. Release of mass rearedE. tricolour under net at the first signs of larval infestation significantly increasedA. proletella-parasitation and reduced infestation compared to netted controls without release. Furthermore, at highest dosage in 2009,E. tricolor had a significant enhancing effect on raw yield and the quality level of marketable yield. Additional on-farm experiments without netting in 2008 and 2009 confirmed the control potential ofE. tricolor. Although the most important project mile stones have been achieved, namely (a)E. tricolour-establishment under net and in the open field, (b) enhanced parasitation corresponding with pest density decline and (c) a positive impact on yield and quality parameters, further research will be necessary. The focus should be on the initial infestation period, optimizing the timing, frequency and required dosage.     

Impact of Pea necrotic yellow dwarf virus (PNYDV) on nodulation,N2 fixation and yield in faba bean (Vicia faba,L.)

Journal of Plant Diseases and Protection - Pea necrotic yellow dwarf virus (PNYDV) is a novel nanovirus in Europe, affecting various grain legumes. The impact of PNYDV on nodulation, symbiotic N2...     

Untersuchungen über Nebenwirkungen verschiedener Niemprodukte beiDaphnia magna Straus (Crustacea: Cladocera)

Zusammenfassung In der vorliegenden Arbeit wurden die Nebenwirkungen von Niemprodukten beiDaphnia magna, einem vielfach für Toxizitätsprüfungen bei Pestiziden verwendeten Testorganismus untersucht.Ein 48 h-Immobilisations-Test wurde mit 6–24 h alten Juvenilen durchgeführt. Die 48 h-EC₅₀ in mg/l und die entsprechende Azadirachtinkonzentration in ppm der Präparate Neem-Azal-S (Azal), AZT-Extrakt (AZT), Margosan-O^® (Margosan) und Niem-Samenkern Extrakt (NSKE) lagen bei 12,3 mg/l (0,04 ppm), 29,3 mg/l (0,34 ppm), 103 mg/l (0,19 ppm) und 1128 mg/l (3,38 ppm). Für 48 h der EC₁₀ exponierte sowie anschließend in nichtkontaminiertem Wasser aufgezogene Juvenile entwickelten sich mit normalen Wachstumsraten und wiesen keine Häutungsschäden auf. Semistatische Exposition führte bei Juvenilen und Adulten zu erhöhten Mortalitätsraten. Überlebende Juvenile entwickelten sich mit geringfügig reduzierten Wachstumsraten und erreichten die Geschlechtsreife. Überlebende Adulte hatten ebenfalls keine Häutungsschwierigkeiten und produzierten lebensfähige, morphologisch normale Nachkommen in verringerter Anzahl.In den beschriebenen Versuchen hatten die formulierten Produkte einen stärkeren Effekt als NSKE in der Reihenfolge Azal>AZT>Margosan>NSKE. Die fehlende Korrelation zwischen den beiD. magna beobachteten Effekten und der insektiziden Hauptkomponente Azadirachtin macht es wahrscheinlich, daß vor allem Emulgatoren und/oder Begleistoffe für die Wirkung der Niemprodukte verantwortlich sind.Die Wirkungen von Niemapplikationen in Naßreisfeldern als Schädlingsbekämpfungs- oder Düngungsmaßnahmen werden im Hinblick auf praxisnahe Bedingungen diskutiert.

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Investigations on side-effects of various neem products onDaphnia magna Straus (Crustacea: Cladocera)

The possible side-effects of the neem products NeemAzal-S (Azal), Azt-Extract (AZT), Margosan-O^® (Margosan) and aqueous neem seed kernel extract (NSKE) onDaphnia magna, the water flea, were investigated under laboratory conditions.A 48h immobilisation test was conducted using 6–24 h old juveniles ofD. magna. The 48h-EC₅₀ in mg/l and the corresponding azadirachtin concentrations in ppm were for Azal 12.3 mg/l (0.04 ppm), for AZT-extract 29.3 mg/l (0.34 ppm), for Margosan-O 103 mg/l (0.19 ppm) and for NSKE 1128 mg/l (3.38 ppm). 48 h exposure of young water fleas to the EC₁₀ and subsequent rearing for 3 weeks in uncontaminated water caused no reduction of the growth rate. Semi-static tests using juveniles and adults of an age of 21 days led to increased mortality but surviving juvenile water fleas developed with slightly reduced growth rates and reached maturity. Surviving adults produced viable, morphologically normal progeny in reduced number. There were no difficulties during moults. In the described tests the formulated products were more effective than NSKE in the order Azal>AZT>Margosan>NSKE. The missing correlation between the observed effects and the content of the main insecticidal ingredient azadirachtin in the neem products leads to the conclusion that the major factors for toxicity of the formulated products are emulsifiers and/or other products. The possible impact of neem products on aquatic microcrustaceans when used for pest control measures or as fertilizers in rice fields is discussed.

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Mit 4 Abbildungen und 3 Tabellen     

Untersuchungen über Nebenwirkungen verschiedener Niemprodukte beiDaphnia magna Straus (Crustacea: Cladocera)

In der vorliegenden Arbeit wurden die Nebenwirkungen von Niemprodukten beiDaphnia magna, einem vielfach für Toxizitätsprüfungen bei Pestiziden verwendeten Testorganismus untersucht.Ein 48 h-Immobilisations-Test wurde mit 6–24 h alten Juvenilen durchgeführt. Die 48 h-EC₅₀ in mg/l und die entsprechende Azadirachtinkonzentration in ppm der Präparate Neem-Azal-S (Azal), AZT-Extrakt (AZT), Margosan-O^® (Margosan) und Niem-Samenkern Extrakt (NSKE) lagen bei 12,3 mg/l (0,04 ppm), 29,3 mg/l (0,34 ppm), 103 mg/l (0,19 ppm) und 1128 mg/l (3,38 ppm). Für 48 h der EC₁₀ exponierte sowie anschließend in nichtkontaminiertem Wasser aufgezogene Juvenile entwickelten sich mit normalen Wachstumsraten und wiesen keine Häutungsschäden auf. Semistatische Exposition führte bei Juvenilen und Adulten zu erhöhten Mortalitätsraten. Überlebende Juvenile entwickelten sich mit geringfügig reduzierten Wachstumsraten und erreichten die Geschlechtsreife. Überlebende Adulte hatten ebenfalls keine Häutungsschwierigkeiten und produzierten lebensfähige, morphologisch normale Nachkommen in verringerter Anzahl.     

Desferoxamine and iron dextran in acute Salmonella cholerae-suis infection in pigs

Serum iron (SI)-related and hematologic changes were evaluated in a herd of weaned pigs inoculated with a strain of Salmonella cholerae-suis, causing 83% mortality within 22 days after inoculation was done. Serum iron concentrations decreased to 35% of base-line values 2 days after inoculation was done, but recovered to near base line subsequently. Total SI-binding capacity (TIBC) decreased gradually for 14 days after inoculation was done. Transferrin (TF) concentrations decreased to near half the base line throughout the postinoculation observation period. The calculated SI saturation coefficient decreased to half the base line, but recovered to or above the base-line value subsequently. Combined observations of SI, TIBC, TF, and SI saturation coefficient concentrations indicated that there was higher saturation of host iron-binding proteins and recruitment of additional iron-binding systems subsequent to 2 days after inoculation was done. Day 2 after inoculation seemed to be a critical period for host iron metabolism. Injection of supplemental iron dextran simultaneously with Salmonella infection resulted in lower mortality of iron-injected pigs (P less than 0.005). A highly significant negative correlation was observed between SI concentration and rectal temperatures after pigs were inoculated with Salmonella (r = -0.54; P less than 0.0001). Hemoglobin concentrations, mean corpuscular volume, and mean corpuscular hemoglobin were not significantly affected by Salmonella infection or iron injection concurrent with Salmonella infection.(ABSTRACT TRUNCATED AT 250 WORDS)