A method for chromosome preparations from large fish specimens using in vitro short-term treatment with colchicine

This paper describes a new technique for preparing mitotic fish chromosomes using short-term in vitro treatment with colchicine. The results show that a large number of good quality metaphases (many suitable for chromosome banding) can be obtained by this technique, which requires an average of 1 h and 30 min for all steps. The procedure considerably reduces the time normally required for chromosome preparations in fish.This work was supported by grants FUNCUNESP, FAPESP and CNPq.The authors are grateful to Mr Renato Devidé for technical assistance.     

An analysis of allozyme,mitochondrial DNA and morphological variation in mussel (Mytilus galloprovincialis) populations from Greece

Three populations ofM. galloprovincialis from northern Greece were investigated using isozyme analysis, discriminant analysis of morphological characteristics and analysis of restriction fragments of mtDNA. For all three types of analysis significant intra- and interpopulation differentiation was found. This differentiation is very noticeable at the mtDNA genotype frequencies. Furthermore, the restriction patterns of mtDNA were different from those reported for Atlantic populations of this species.     

A simple method for the preparation of hydra chromosome spreads: introducing chromosome counts into hydra taxonomy

Summary A simple method to prepare chromosome spreads of hydra is described. Chromosome counts for a non-symbiotic brown hydra,Hydra vulgaris attenuata, and the Swiss strain of a symbiotic green hydra indicated a diploid number of about 2n=30 in each case. It is suggested that chromosome number may be used to define hydra species more precisely.This work was done while A. R. and M. R. were on leave in Oxford. We thank Prof. D. C. Smith F. R. S. for providing laboratory facilities. We wish to thank Prof. Smith and Dr A. E. Douglas for reading earlier drafts of this paper.     

A radioisotopic method for the determination of S-adenosyl-L-homocysteine in tissues in the 10(-7) M range

S-Adenosyl-L-homocysteine is able to bind to brain membranes. We used this characteristic to measure the level of S-adenosyl-L-homocysteine in rat brain tissue. The method is rapid, at the same time very sensitive (down to 10(-7) M) and specific.     

Formation of plantlets from callus cultures of ginseng (Panax ginseng)

Summary From callus cultures ofPanax ginseng C.A. Mayer, shoots and roots were systematically formed at a high rate (in all flasks) under optimal culture conditions. The chemical constituents and the morphological structures of the differentiated plantlets closely resembled those of the native plants.Part 44 in the series Studies on Plant Tissue Culture. For Part 43 see Yoshikawa, T., and Furuya, T., Planta med. (1985) 110.     

A new method for obtaining blood from a small mammal without injuring the animal: use of Triatomid bugs

Summary By means of hungry Triatomid bugs, samples of blood (40–200l) can be obtained from small mammals, such as bats, without causing any harm to the animals. The blood can be extracted from the gaster of the bug immediately after the bug has finished sucking. The method was successfully used for measuring the energy budget by the doubly labeled water method, and for obtaining material for lymphocyte cultures, and may prove useful in other fields, too.M. Volleth is very much obliged to Prof. Dr R. A. Pfeiffer for giving her the opportunity to work at the Institute of Human Genetics.     

A simple method for in vivo testing of glandular enzymatic activity on potential precursors of larval defensive compounds inPhratora species (Coleoptera: Chrysomelinae)

The presence of glandular -glucosidase and oxidase-specific activities, and the possible role of phenolglucosides and related compounds as precursors for larval defensive compounds, were directly demonstrated by introducing salicin, saligenin and helicin into the defensive glands ofPhratora species.Ph. tibialis andPh. laticollis that normally secrete endogenously-produced iridoid monoterpenes and do not use phenolglucosides from their food sources as precursors, were able to produce salicyladehyde from helicin when the latter was introduced into the defensive glands.