Female gonad of moles, genus Talpa (Insectivora, mammalia): ovary or ovotestis?

The female gonads of moles (genus Talpa) are composed of a cortex, functioning as an ovary, and a medulla, which is structurally similar to that of the testis. In the female reproductive apparatus there are masculine glandular annexes, such as a bilobate prostate, two Cowper glands, and a penis-like clitoris. All these features have recently led to the hypothesis of the presence of hermaphroditism due to sex-reversal in Talpa. The purpose of this study is to understand the functional significance of the structural organization of the female gonads in order to verify this hypothesis. Histological, histochemical and ultrastructural analyses have been carried out on several gonads of both sexes of two species: T. europaea and T. romana, including three fetuses. In both species, the cortical region of the female gonad shows a regular oogenetic activity. While the medulla is composed of interstitial cells that are partly organized in cord-like structures, no spermatogenetic activity has been ever observed inside of them. A histochemical analysis shows that in both sexes the interstitial cells secrete steroids, presumably estrogens as well as androgens. The presence of androgens in the female gonads would therefore explain the persistence of male glandular annexes in the female reproductive apparatus and both the sexual and behavioral monomorphism typical of the genus Talpa. Nonetheless, the female gonad of moles is a real ovary and a well-defined gonochorism exists. Therefore, there is no reason to assert the presence of hermaphroditism due to sex reversal.

Variations in properties of L-forms of Pseudomonas aeruginosa.

In a study of the pathogenic potentials of Pseudomonas L-forms, three unstable L-forms were derived by carbenicillin inductionfrom a mouse virulent strain of Pseudomonas aeruginosa, Rosenthal 180. One L-form, induced on a sucrose-stabilized medium, grew more slowly and differed in a number of properties from two other L-forms induced on a medium supported with polyvinylpyrilidone. After adaptation to a common liquid medium, the three L-forms differed with respect to colonial shape on solid medium, growth rate, certain biochemical properties, antibiotic sensitivities and antigenic surface, and virulence for mice. The L-form may revert in vitro to a serotype different from that of the parent culture. The revertant may acquire new antibiotic resistances and sensitivities in the absence of previous exposure to the drugs and enhanced resistance to the L-inducing agent. The three L-forms showed a characteristically lower, but wide, range of virulence than did the parental form. Though death of mice was accompanied by reversion of the L-forms in vivo to the bacterial form, reversion in vivo was not necessary for virulence of L-forms. Modification of residual cell wall antigens accompanied the induction of each L-form as determined by type-specific antisera.