Lodovico Galleni

A rapid fibroblast culture technique for high resolution karyotypes

Abstract For chromosomes studies in mammals, we developed a rapid fibroblast’ culture techique which is particularly advantageous for small mammals when sacrifice is not desirable. Small exterior biopsies are sequentially digested in EDTA/Trypsin and collagenase. Cell cultures can be subdivided and harvested in about one week, compared to the 3–4 week period normally required. The use of antibiotics limits the inconvenience of microbial contamination and permits, transport of samples from the field to the laboratory over a period of one week.

Chromosomal evolution in marine triclads and polyclads (Turbellaria)

From an analysis of chromosomal mutations in seven species among five genera of marine triclads and polyclads, three different types of mechanisms of such mutations are identified: 1) rearrangement involving the centromere such that its position is changed, 2) rearrangement of whole chromosome arms, and 3) Robertsonian mechanisms. These mechanisms are the same as those reported for freshwater turbellarians, but aneuploidy and polyploidy, which are common in freshwater species, were not detected in these marine turbellarians.

Speciation in the Savi pine vole, Microtus savii (De Sel. L.) (Rodentia, Arvicolidae): A theoretical biology approach

Abstract A theoretical approach to the problem of speciation is developed starting from Lovelocks Gaia hypothesis. In this hypothesis the metaphor of the Biosphere as‐a organism is present. Developing the metaphor implies that evolution is the way the Biosphere maintains dynamic homeostasis, and speciation has the adaptive value of an increase of biological diversity. An experimental analysis carried out on speciation in the Savi pine vole suggests that the speciation event is connected with heterochromatin amplification in sex chromosomes of these incipient species. Do gene amplifications have adaptive value? A working hypothesis where amplification is a way to start the speciation process, and where speciation has the adaptive value of increasing diversity, is proposed.

Evidence for planctonic feeding in Götte's larva of Stylochus mediterraneus (Turbellaria-Polycladida)

Abstract Gottes larvae of Stylochus mediterraneus were examined at both the light and the scanning electron microscope. Specimens fed on the green alga Dunaliella sp. showed green substances in their gut. Moreover, a ciliated protozoan of the genus Aspidisca was found half inserted in the mouth of a Gottes larva. These data are new evidence in favour of planctotrophic feeding in this type of larva.

Chromosome bands in freshwater triclads

Four species of Triclads belonging to three families, Dugesia polychroa and Dugesia mediterranea (Dugesiidae), Planaria torva (Planariidae) and Dendrocoelum lacteum (Dendrocoelidae) were studied for chromosome banding: C-banding for all the species, ASG banding for Dugesia polychroa and G-banding for Dugesia polychroa and Dugesia mediterranea. C-banding results for Dugesia lugubris-polychroa group suggest a high level of heterochromatin evolution in the group. Small bands strictly limited to the centromeric region were seen in Dugusia lugubris and this pattern is similar to the patterns of some species belonging to other families, notably Planaria torva and Dendrocoelum lacteum. This could be considered a primitive character. In contrast numerous heterochromatin bands which are useful to characterize the different karyotypes were seen in Dugesia polychroa and Dugesia mediterranea. Our data suggest that heterochromatin is important in freshwater triclad speciation.

Preliminary report on the effects of salinity on the early development of Stylochus mediterraneus (Turbellaria: Polycladida)

Summary The effects have been studied of different salinities on the early stages of development of the Turbellarian Polyclad Stylochus mediterraneus Galleni. Optimal salinities are about 30%o. Variation away from this value increases the incidence of unhatched embryos, even if development is not greatly altered. On the contrary, at the highest tested salinities (50%o; 60%o) and the lowest (18%o), embryos are affected by great alterations in their morphology.

An Axiomatic Approach to Some Biological Themes

In this paper we continue the enterprise of elaborating an axiomatic framework suitable for modern Biology, started in 1,2,3. We isolate and propose to the attention of the scientific community a few axioms expressing some basic biological facts and their theoretical interpretations. We hope we can foster criticism and contributions from researchers of any field of the Natural Sciences. In fact, we conceive this paper as part of a general research programme on the Foundations of Science, originated in the Eighties by E. De Giorgi at the Scuola Normale Superiore, Pisa and carried on by several researchers after his death in 1996 (see 4,5,6,7,8). The aim of this programme is not to provide safe and unquestionable grounds to scientific activity, but rather to develop conceptual environments where this activity can be carried out naturally and without artificial constraints, and the notions considered in various disciplines can be presented in a simple and clear-cut way, so as to allow for both a deeper analysis by researchers in the field, and a proficuous interdsciplinary debate.