Easier detection of invertebrate "identification-key characters" with light of different wavelengths

Evolutionary arms-races between avian brood parasites and their hosts have typically resulted in some spectacular adaptations, namely remarkable host ability to recognize and reject alien eggs and, in turn, sophisticated parasite egg mimicry. In a striking contrast to hosts sometimes rejecting even highly mimetic eggs, the same species typically fail to discriminate against highly dissimilar parasite chicks. Understanding of this enigma is still hampered by the rarity of empirical tests - and consequently evidence - for chick discrimination. Recent work on Australian host-parasite systems (Gerygone hosts vs. Chalcites parasites), increased not only the diversity of hosts showing chick discrimination, but also discovered an entirely novel host behavioural adaptation. The hosts do not desert parasite chicks (as in all previously reported empirical work) but physically remove living parasites from their nests. Here, I briefly discuss these exciting findings and put them in the context of recent empirical and theoretical work on parasite chick discrimination. Finally, I review factors responsible for a relatively slow progress in this research area and suggest most promising avenues for future research.     

Evaluation of a commercial E<Superscript>rns</Superscript>-capture ELISA for detection of BVDV in routine diagnostic cattle serum samples

Background  

Bovine viral diarrhoea virus (BVDV) is an important pathogen in cattle. The ability of the virus to cross the placenta during early pregnancy can result in the birth of persistently infected (PI) calves. These calves shed the virus during their entire lifespan and are the key transmitters of infection. Consequently, identification (and subsequent removal) of PI animals is necessary to rapidly clear infected herds from the virus. The objective of this study was to evaluate the suitability of a commercial E^rns-capture ELISA, in comparison to the indirect immunoperoxidase test (IPX), for routine diagnostic detection of BVDV within a control programme. In addition, the effect of passive immunity and heat-inactivation of the samples on the performance of the ELISA was studied.     

Studies upon the copper fungicides: VII. The solution of copper from dressings on the pea seed

During the process of swelling pea seeds yielded substances to water which were capable of dissolving the insoluble copper dressings normally applied to the seed to prevent 'pre-emergence damping off'. This occurred under conditions in which soil factors were eliminated and irrespective of whether the dressing was on the surface of the seed or treated separately. Copper was readily taken into solution from dried 4:4:50 Bordeaux Mixture by water in which peas had been soaked, a circumstance which proved that the formation of soluble complex forms of copper was involved.
A chemical investigation on the solution obtained by soaking peas in water showed that volatile acids or their salts were present together with a protein-like material in colloidal solution. The occurrence of amino derivatives and other nitrogenous materials as well as carbohydrates was indicated and evidence of the presence of asparagine and citrate was also obtained.
The suggestion is made that both the fungicidal and phytocidal actions of insoluble copper dressings on pea seed depend largely on the effect of the pea seed exudates, notably colloidal protein-like material and certain amino derivatives, in bringing copper into solution.     

Studies upon the copper fungicides. IX. Investigations with the exudate from fungus spores

Determinations have been made of the copper dissolved from pure copper compounds by water, by a standardized solution of the exudate of Neurospora sitophila spores, by standard solutions of malic and succinic acids and their sodium salts, and by glycine and mannitol.
The results compared with the known fungicidal performances of the copper compounds show that the amounts of copper yielded to water and to the standardized spore extract or glycine solution provide an indication of fungicidal properties.
Although soluble copper in excess of that dissolved by water can only appear from alkaline Bordeaux deposit by complex ion formation, results show that this is not necessarily the only means by which copper can dissolve from other copper compounds.
In a chemical investigation of the exudate of N. sitophila spores, mannitol, succinate and fumarate have been isolated. None of these materials can dissolve an appreciable amount of copper from alkaline Bordeaux deposit. Malate, found by other workers to be a constituent of the exudate of N. sitophila spores cultured on potato dextrose agar, has not been detected in such a solution from spores grown on malt agar. The quantity of mannitol in spore exudate has been shown to depend on the nutrient medium on which the fungus is grown.     

SYSTEMIC FUNGICIDES INTRODUCTION

The idea of controlling plant diseases by introducing curative chemicals into the plant goes back many years. All the early work, which has been reviewed by Müller (1926), was of an empirical nature and although claims were made from time to time that particular treatments were effective, no clear and reliable method ever became established for controlling a plant disease by internal therapy. Within the last few decades, however, such treatment for certain animal diseases with substances possessing antibacterial properties has given spectacular results. This success in the animal led to a renewed interest in the control of plant diseases by similar means, though it was of course recognized that the animal, with its circulating blood system capable of carrying chemicals rapidly to all tissues, is very different from the plant.