Maria Filomena Caliendo

Morphological Differentiation and Genetic Structure in Island Lizard Populations

Abstract Only some island populations of Podarcis sicula are hyperchromatic. The study of this phenomenon and its relationship with the lizards of the mainland and other islands, exhibiting a “normal” coloration, provides useful hints in our understanding of evolutionary mechanisms that have created the observed morphological variation. We performed a comparative morphological and genetic analysis of a hyperchromatic lizard population from Licosa Island, and compared the data with that obtained from normal-colored lizard populations both from Ustica and Cirella islands in the Tyrrhenian sea and from nearby mainland Italy. Morphological and microsatellite gene differentiation in the hyperchromatic Licosa population appears to have been much more rapid than the molecular evolution of the mtDNA. We discuss herein that the comparison of hyperchromatism and other types of morphological variation with molecular data in island populations of lizards may provide useful hints as to evolutionary mechanisms.

Role of lipids in the physiology of the testis of Rana esculenta: Annual changes in the lipid and protein content of the liver, fat body, testis and plasma

Abstract We have described in the male green frog, Rana esculenta, modifications in the total lipids and protein of the testis, fat body, liver and plasma throughout the year. We have considered 1) the fat bodies as the main deposit for lipids in the body because the lipid concentration in this organ constitutes at times more than 50% of the wet tissue, and 2) the liver as the main centre for lipid synthesis. The lipids are released in the plasma and subsequently incorporated in the fat body and in the testis. Annual changes in these parameters have been correlated with gametogenetic activity. We have emphasized the importance of the fat body in controlling testicular activity and the implications of hormones and environmental cues.

Annual testicular activity in the gray partridge (Perdix perdix L.)

Seasonal changes in plasma androgens, testicular total protein content, gonosomatic index, and spermatogenic activity were studied in the grey partridge, Perdix perdix. Moreover, testicular androgen output after stimulation with ovine LH (oLH) was tested in vitro during different periods of the sexual cycle. Androgens and the gonosomatic index peaked in April, during which all the spermatogenic stages were observed. Total protein content in the testes was highest in January and March. Gonadal responsiveness to oLH was found to increase in the period April-May in coincidence with the hormone peak in the plasma, while February testes were irresponsive.

Seasonal lipid composition in the liver, fat body and gonads of Rana esculenta

Abstract Seasonal changes are described in the lipid of liver, fat body and gonads of the frog. Analysis reveals that most of the lipid classes observed are present in the fat body and gonads in March. The testis and the female fat body show the most variable pattern according to the season. These data support the hypothesis that both the liver and fat body are involved in gonadal control and that this interaction modifies seasonally.

SEASONAL BREEDING IN THE ITALIAN SPARROW: PLASMA ANDROGEN LEVELS AND SPERMATOGENESIS

In this research we studied the spermatogenesis and circulating androgen levels in the male Italian sparrow. A seasonal pattern is shown, and evidence is provided that the Italian sparrow has multiple-clutch breeding activity. In particular, we have observed a winter resurgence of testicular activity, as indicated by active spermatogenesis and a relatively higher plasma androgen level as compared to the summer hormone levels. No breeding males were ever observed during the winter period, and an apparent resurgence of gametogenesis may simply be considered as a transient phenomenon. We suggest that multiple-clutch breeding activity and transient winter resurgence of spermatogenesis reflect the derivation of this species from an ancestral population, probably the progenitors of P. hispaniolensis, spread from Africa to the Italian peninsula.

Temporal pattern of labeling of liver, blood, fat body and testis lipids in Rana esculenta

Abstract This study demonstrates that the temporal pattern of incorporation of a labeled lipid precursor (Acetyl‐CoA (1‐C14)) in the liver, fat body and testis of the frog may vary during the reproductive cycle. The magnitude of this incorporation is greater in the intact autumn frogs in which the liver is the first organ to show peak lipid labeling, followed in time by the peak labeling of the fat body lipids and finally of the testis lipids. In other periods of the year this precise time sequence of incorporation is either absent or not so clear. The blood lipids are also labeled rapidly, but the amount of radiolabel incorporated usually declines significantly 3 hrs after tracer injection. Results obtained in the frogs deprived of both the fat bodies, or both the testes, or one fat body and/or testis showed that the fat bodies represent a necessary anatomical step for liver lipids en route to the testis, the blood being the main channel between the liver and the fat body.

Lipids and fertility in the female Mus musculus domesticus

Abstract In the female mouse the best known effects of pheromones concern the control of estrous cycle and pregnancy. We studied the effect of lipidic compounds (glycerides, sterols and steroids, fatty acids and their esters), extracted from female litters, on mature female mice reared with the male. Lipid fractions were given to mature females through three routes: intraperitoneally, per os and by olfaction. Ovary- and uterus-somatic index, number of corpora lutea, follicles, blastocysts and newborn were considered. There was no effect if material was given i.p. of by taste. Only when administered by olfaction the sterolic and fatty acids fractions modified our parameters (except the ovary-somatic index); the most remarkable action was due to fatty acids of fatty acid-like compounds. We hypothesize a multiple action of different pheromones through the hypothalamus-gonadal axis.