Contribution a l'étude biologique d'Opius concolor Szepl. (Hym. Braconidae) En élevage de laboratoire

Summary It is possible to obtain a permanent breeding ofOpius concolor by use of third instar larvae ofCeratitis capitata as host. TheOpius obtained by such breeding will accept to parasitize successfully the larvae ofDacus oleae. This breeding will allow the study of many obscure points of the biology of the parasite, mainly conditions by which the host is chosen by the laying female and the reason of the endoparasitical development in the two hosts. It should be useful to know if the ecological strains are differenciated by similar experimentation withO. siculus Monastero. It should be aslo interesting to extend this experience to other Trypetid species (for instance to the hosts ofOpius humilis Silv.: Braconid which is spread in Hawaii might be a synonym ofconcolor asFischer supposes). This breeding could be eventually used to start the study and realisation of industrial multiplications in view of the biological control applications.      

Mineral Preservatives in the Wood of Stradivari and Guarneri

Following the futile efforts of generations to reach the high standard of excellence achieved by the luthiers in Cremona, Italy, by variations of design and plate tuning, current interest is being focused on differences in material properties. The long-standing question whether the wood of Stradivari and Guarneri were treated with wood preservative materials could be answered only by the examination of wood specimens from the precious antique instruments. In a recent communication (Nature, 2006), we reported about the degradation of the wood polymers in instruments of Stradivari and Guarneri, which could be explained only by chemical manipulations, possibly by preservatives. The aim of the current work was to identify the minerals from the small samples of the maple wood which were available to us from the antique instruments. The ashes of wood from one violin and one cello by Stradivari, two violins by Guarneri, one viola by H. Jay, one violin by Gand-Bernardel were analyzed and compared with a variety of commercial tone woods. The methods of analysis were the following: back-scattered electron imaging, X-ray fluorescence maps for individual elements, wave-length dispersive spectroscopy, energy dispersive X-ray spectroscopy and quantitative microprobe analysis. All four Cremonese instruments showed the unmistakable signs of chemical treatments in the form of chemicals which are not present in natural woods, such as BaSO₄, CaF₂, borate, and ZrSiO₄. In addition to these, there were also changes in the common wood minerals. Statistical evaluation of 12 minerals by discriminant analysis revealed: a. a difference among all four Cremona instruments, b. the difference of the Cremonese instruments from the French and English antiques, and c. only the Cremonese instruments differed from all commercial woods. These findings may provide the answer why all attempts to recreate the Stradivarius from natural wood have failed. There are many obvious implications with regard to how the green tone wood should be treated, which chould lead to changes in the practice of violin-making. This research should inspire others to analyze more antique violins for their chemical contents.     

Dynein anchors its mRNA cargo after apical transport in the Drosophila blastoderm embryo

Molecular motors actively transport many types of cargo along the cytoskeleton in a wide range of organisms. One class of cargo is localized mRNAs, which are transported by myosin on actin filaments or by kinesin and dynein on microtubules. How the cargo is kept at its final intracellular destination and whether the motors are recycled after completion of transport are poorly understood. Here, we use a new RNA anchoring assay in living Drosophila blastoderm embryos to show that apical anchoring of mRNA after completion of dynein transport does not depend on actin or on continuous active transport by the motor. Instead, apical anchoring of RNA requires microtubules and involves dynein as a static anchor that remains with the cargo at its final destination. We propose a general principle that could also apply to other dynein cargo and to some other molecular motors, whereby cargo transport and anchoring reside in the same molecule.     

A Drosophila model to study the functions of TWIST orthologs in apoptosis and proliferation

The twist gene has been characterized for its role in myogenesis in several species. In addition, in mammalian cultured cells, it has been shown that twist is a potential oncogene antagonizing p53-dependent apoptosis. To study, in vivo, the role of twist in apoptosis and proliferation, we constructed transgenic Drosophila lines allowing ectopic expression of different twist orthologs. We report that: (i) Drosophila twist induces apoptosis and activates the reaper promoter, (ii) nematode twist induces arrest of proliferation without apoptosis, and (iii) human twist retains its potentialities observed in mammalian cultured cells and antagonizes Drosophila p53-dependent apoptosis. In addition, we show that human twist is able to induce cell proliferation in Drosophila. Data suggest that the pathway by which human twist antagonizes Drosophila p53 could be conserved. These transgenic lines thus constitute a powerful tool to identify targets and modifiers of human twist.     

An EGF-Responsive Neural Circuit Couples Insulin Secretion with Nutrition in Drosophila

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Première expérimentation à grande échelle,de lutte biologique contre la mouche de l'Olive (Dacus oleae Gmel.) au moyen d'Opius concolor Szepl. Siculus mon. en sicile

Summary In 1966, an important experiment of biological control againstDacus oleae Gmel. was undertook in a new area of Sicily to the west of Palermo. More than eight millionOpius concolor siculus were released in orchards including about 250 000 olive trees. The establishment of the parasite was observed at different rates in all the area, and a satisfactory protection of the crop was noticed. Some interesting informations on the factors concerning the Braconid establishment, and the chalcidid indigenous population fluctuations are pointed out by the authors.

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Ont participé à cette expérimentation:P. Genduso, G. Liotta, G. Mineo, S. Ragusa de l'Institut d'Entomologie agricole de Palerme etA. Sciortino, boursier, qui ont suivi et contr?lé en particulier l'activité des Insectaria et effectué les lachers, etR. Pralavorio de la Station de Zoologie agricole et de Lutte biologique d'Antibes qui s'est plus spécialement occupé de l'étude écologique et de l'organisation des élevages d'Antibes.