The interaction of endosulfan with the Collembolan, Proisotoma minuta (Tullberg): toxicity, the effects of sub-lethal concentrations and metabolism

An increased level of the Collembolan, Proisotoma minuta Tullberg was found in the cotton-growing areas of New South Wales, Australia. They were regularly exposed to endosulfan, a highly insecticidal compound. Toxicity, sub-lethal effects and metabolism of endosulfan were studied in P minuta that had been successfully maintained in a plaster of Paris and charcoal mixture substrate with freeze-dried yeast as a food. The 168-h LD50 values were 0.011, 0.049 and 0.055 mg liter(-1) for alpha- and beta-endosulfan and endosulfan sulfate, respectively. When P minuta were exposed to non-lethal concentrations of the endosulfans, egg production was inhibited. On recovery from the toxic effects of the endosulfans they resumed production of viable eggs. Conversion of alpha- and beta-endosulfan to endosulfan sulfate was found and the endosulfan sulfate could be further metabolized. The rate of metabolism of alpha-endosulfan was greater than that of beta-endosulfan and the product of endosulfan sulfate metabolism was not identified.     

Decay resistance against <Emphasis Type="Italic">Coriolus versicolor</Emphasis> in Sessile oak (<Emphasis Type="Italic"> Quercus petraea </Emphasis>Liebl.): analysis of the between-tree variability and correlations with extractives,tree growth and other basic wood properties

Abstract Weight loss due to fungus Coriolus versicolor has been measured on 614 samples according to the NF EN 113 norm. Up to eight samples were cut at breast height (two opposite radii×four radial positions in heartwood) from 82 mature sessile oaks ( Quercus petraea Liebl.) originating from contrasting regions, silvicultural schedules and site qualities in France. The following points are addressed in the paper: (i) contribution to the total variability for weight loss of the effects tree, position in the tree, as well as their interaction; (ii) percentage of wood samples and trees in each of the five classes of natural durability defined by the norm NF EN 350–2; (iii) test of the effects of region, silvicultural schedule and site quality on weight loss and evaluating their contribution to the total variation; and (iv) correlations at tree level between weight loss and several traits related to tree growth and basic wood properties (density, swelling, grain angle, multiseriate wood rays characteristics, extractives content). The results are discussed with a view to aid the forest manager as well as the log/wood user to take advantage of the high level of between-tree variability observed as natural durability against C. versicolor.     

Different Patterns of Host Genes are Induced in Rice by Pseudomonas syringae, a Biological Inducer of Resistance, and the Chemical Inducer Benzothiadiazole (BTH)

Rice seedlings treated with the synthetic compound benzo(1,2,3)thiadiazole-7-carbothioic acid S-methyl ester (BTH) acquired resistance to subsequent attack by the rice blast fungus Magnaporthe grisea (Hebert) Barr. BTH (trade name Bion) has been released to the market as a plant protecting agent for rice. Here, we analysed the pattern of expressed genes in rice plants treated with BTH, and compared this pattern with those induced by the formerly discovered resistance inducer 2,6-dichloroisonicotinic acid (INA) and by Pseudomonas syringae pv. syringae, a non-host pathogen inducing a hypersensitive response. Both INA and BTH induced similar patterns of genes, suggesting that these compounds are functional analogues. In contrast, the patterns induced by the chemical inducers and by P. syringae were clearly dissimilar.     

Release of carbon and nitrogen compounds by plant roots and their possible ecological importance+

The root-borne C- and N-flux in the plant/soil system was studied by determining the ¹⁴C- or ¹⁵N-balances in pot trials with soil as a substrate (¹⁴CO₂- or ¹⁵NH₃-application to the shoots, comparison of sterile and nonsterile treatments for quantification of root-borne substances). The following results were obtained: 1. The amount of (primary) root-borne carbon compounds released into soil was (besides root respiration) 11—20% of net-CO₂-assimilation or 13—32% of the ¹⁴C incorporated into the plants (= 1 t C · ha^—1). 5—6% of ¹⁵N assimilated by the plants were released as root-borne N compounds (= 15 kg N · ha^—1). 2. A considerable portion of the root-borne C (about 6% = 600 kg C · ha^—1) was found in the rooted soil zone at the end of the experiments (rhizodeposition). 3. (Primary) root-borne C and N compounds found in immediate vicinity of the roots (about 60—80%) were mainly water soluble, whereas most of the C and N compounds found in a greater distance were water insoluble. The water soluble exudates consisted mainly of neutral (carbohydrates) and acid fractions (organic acids). The basic fraction (amino acids) made up a small portion only. 4. The root-borne C and N compounds influenced the nutrient balance of soil and plant directly and/or indirectly via microbes (depending on species, variety and nutritional status of plants). 5. Microbes stimulated the release of C- and N-compounds, but rapidly respired 65—85% of the root-borne C-compounds, thereby putting a burden on the C-budget of the “host” plant. 6. It could be shown by the example of hup⁺ Rhizobium meliloti strains (tested by ³H₂-incorporation) and the wheat-Serratia-association, that energy efficient microbenplant systems can improve plant performance.     

Wild halophytic species as forage sources: Key aspects for plant breeding

The use of wild halophytic species as forage resources in saline environments has gained increasing attention. Argentina ranks third in area of saline soils in the world, with a third of its territory showing various degrees of salinity, sodicity and/or alkalinity. On this type of soils, rangelands are the main forage resource for livestock production. Many wild species have forage potential and can also be used for the rehabilitation of rangelands and for intercropping. Information about these species, as well as on the physiological and genetic bases associated with salinity tolerance, provides relevant tools for efficient selection methods. This study addresses Argentine wild halophyte species with forage potential and describes selection criteria with an emphasis on the following taxa: (a) Poaceae: subfamily Chloridoideae and tribes Paniceae and Triticeae, (b) Fabaceae and (c) Amaranthaceae (formerly known as Chenopodiaceae). The review is intended to contribute to the general discussion on strategies for the improvement of wild plant genetic resources, using forage species naturally growing in saline soils in Argentina as a case study.     

The isolation of Salmonella anatum from the pig and sheep in New Zealand

Extract

Rifamastene § § Trademark of Gruppo Lepetit S.P.A., Milan, Italy. is a water-miscible formulation of the new antibiotic rifamycin SV designed for use as an udder infusion for the treatment of bovine mastitis.     

Feeding preferences of the collembolan Onychiurus sinensis for fungi colonizing holm oak litter (Quercus rotundifolia Lam.)

Ten fungi isolated from decaying holm oak leaves (Quercus rotundifolia Lam.) have been presented to the collembolan species Onychiurus sinensis (Hexapoda). The attractiveness and selectivity of the ten fungi was investigated taken into account the effect of the substrate on which the fungus was growing (malt-agar or litter) and the effect of fungal odour. Furthermore, moulting, growth, survival and reproduction of O. sinensis in the presence of each of the ten test fungi were studied. Mucor plumbeus and Trichothecium roseum were the most preferred whatever the culture substrate and their odour was the most attractive. Two fungi (Penicillium spinulosum and the Basidiomycete S41) attracted Collembola by their odour but were not preferred as food sources. The animals could survive and reproduce on a mono-diet of several of our test fungi, but not on the Basidiomycete S41 and on Trichoderma polysporum.     

Über Fliegenplage in Kleintierställen,Einsatz chemischer Bekämpfungsmittel und Resistenz

Zusammenfassung Infolge ungenügender, nur oberflächlicher und in zu großen Zeitabständen erfolgender Reinigung von Kleintierställen kann es darin zu einer eigenen Fliegenzucht kommen. Zur Unterbindung einer ständigen Fliegenplage sollten daher alle Boxen und Käfige in Kleintierställen regelmäßig in Abständen von etwa 8 Tagen in den Sommermonaten und von etwa 10–12 Tagen in den Wintermonaten gründlich gesäubert werden. Bei wiederholter Anwendung von Wandspritzmitteln auf der Basis chlorierter Kohlenwasserstoffe, in solchen, längere Zeit nur ungenügend gereinigten Ställen, ist die Gefahr einer Herauszucht giftunempfindlicherer Fliegenstämme wegen der dichten Generationsfolge besonders gegeben. An einem seit drei Jahren mit Bekämpfungsmitteln behandelten und in den letzten 1 1/2 Jahren fortlaufend auf seinen Fliegenbefall kontrollierten Stall wird das allmähliche Eintreten von Resistenzerscheinungen bei Stubenfliegen in der Praxis und deren Nachprüfung im Laboratorium beschrieben.