Anna Maria Avanzati

Multiple symbiosis in the leafhopper Scaphoideus titanus (Hemiptera: Cicadellidae): details of transovarial transmission of Cardinium sp. and yeast-like endosymbionts.

Scaphoideus titanus is the insect vector of flavescence dorée (FD), a yellow disease of grapevines. Observations on adult females and nymphs of S. titanus showed that this insect is associated with a complex microbial community. Ultrastructural analysis showed that the fat body, salivary glands and ovary of the insect harbour microorganisms showing the brush-like structure typically observed in the genus Cardinium. In particular, it has been shown that these symbiotic bacteria are present both in the follicular cells and in the eggs. In addition, cells resembling bacteriocytes, harbouring numerous Cardinium symbionts in the cytoplasm, were observed in the apical portion of the ovary in adult females. These cells are likely responsible for bacterial transmission to the ovary. Optical microscopy showed that the fat body harbours an enormous population of yeast-like symbionts (YLSs). Ultrastructural observations showed that these symbionts are enclosed within specialized cells of the fat body and are also present in the ovary, where they are found in both the follicular cells and the eggs. There is thus evidence that both Cardinium and the YLSs are transovarially transmitted to the offspring. To our knowledge, S. titanus is the sole insect known to transmit two different kinds of symbionts to the eggs, a prokaryote and an eukaryote. Gene sequence analysis and in situ hybridization led to the identification of YLSs as members of the class Sordariomycetes (=Pyrenomycetes). Finally, ultrastructural observation of the midgut content revealed the presence, in both adult females and nymphs, of a complex microbial community, which include a phytoplasma-like microorganism, likely the agent of FD.

Biological Tools to Study the Effects of Environmental Contaminants at the Feto–Maternal Interface

The identification of reproductive toxicants is a major scientific challenge for human health. Prenatal life is the most vulnerable and important time span of human development. For obvious ethical reasons, in vivo models cannot be used in human pregnancy, and animal models do not perfectly reflect human physiology. This review describes the in vitro test models representative of the human feto–maternal interface and the effects of environmental chemicals with estrogen-like activity, mainly bisphenol A and para-nonylphenol, with a particular emphasis on the effects at low, nontoxic doses similar to concentrations commonly detected in the population.

Notulae oribatologicae XLI. some new Steganacarus species belonging to the magnus group (Acarida, oribatida)

Abstract Two new species closely related to Steganacarus (Steganacarus) magnus (Nicolet) are described. S. (S.) michaeli can also be genetically differentiated from known congeneric species such as S. (S.) hirsutus Perez-Inigo by biochemical methods. Some biogeographic observations are made about the collection sites of the two new entities.

Notulae oribatologicae XLVIII. the taxonomic position of Steganacarus brevipilus (Berlese, 1923) and Tropacarus in the Steganacaridae system (Acarida, Oribatida)

Abstract The classical species, Steganacarus (Tropacarus) brevipilus (Berlese, 1923), was analyzed morphologically, biogeographically and genetically in order to exactly define its taxonomic position in the Steganacarid system. The traditional morphological character of the median notogastral ridge and the gene-enzyme systems confirm the close affinity of brevipilus to S. (T.) carinatus (Koch) and the validity of subgeneric rank for Tropacarus.

Notulae oribatologicae XLVII. Intraspecific variability in Tropacarus: The example of Steganacarus (Tropacarus) pulcherrimus (Berlese, 1887) junior synonym of S. (T.) carinatus (Koch, 1841) (Acarida, Oribatida)

Abstract Morphological, ecological, biogeographic and genetic evidence is presented to suggest the synonymy of Steganacarus (Tropacants) pulcherrimus (Berlese) and the earlier S. (T.) carinatus (C.L.Koch).

Taxonomic revision of Amerus troisi (Berlese, 1883) (Acari, Oribatida, Ameridae) using morphological and biochemical characters

This paper redescribes the classical taxon Amerus troisi (Berlese, 1883) on the basis of topotypical material. A new species, Amerus cuspidatus, characterized by short interlamellar setae and a distinct rostral morphology, is also described. In spite of overlapping biogeographical distributions, biochemical analysis indicates that the two Amerus species are clearly differentiated.

Notulae oribatologicae xlix. taxonomic revision of Steganacarus (Steganacarus) applicatus (Sellnick, 1920) and the description of a new west Mediterranean Steganacarus species (Acarida, Oribatida)

Abstract The classical taxon, Steganacarus (Steganacarus) applicatus (Sellnick, 1920), is redescribed on the basis of the type material found in Berleses Collection. Analysis of many European and North African populations reveals the existence of at least another closely related new species with a geographic distribution restricted to the west-Mediterranean countries and testifying ancient land connections.

Fine structure of the female reproductive system in a viviparous insect, Glossina morsitans morsitans (Diptera, Glossinidae)

The female reproductive system of the tsetse fly Glossina morsitans morsitans is analysed by scanning electron microscopy (SEM). The study focuses in particular on the choriothete, a peculiar uterine structure involved in the viviparous mode of reproduction of Glossina morsitans morsitans. Under light microscopy, the choriothete appears formed by numerous tongue-like folds projecting towards the uterine lumen and lined by a thin cuticle. SEM analysis highlights for the first time a distinctive new feature that is not visible by traditional histological methods. That is a cuticular covering of the choriothete, which shows numerous thorns in the form of crest-like structures arranged in nearly parallel lines. The role of the choriothete in pregnancy and in larval nourishment is discussed.

Cytokine components and mucosal immunity in the oviduct of Xenopus laevis (amphibia, pipidae)

Most studies on the mucosal immunity in female reproductive tissues have been performed in mammals. In all species, apart from their reproductive strategies, immunity in the genital mucosa is required to defend the host against luminal pathogens. In this study we investigated the role of the innate immunity of the oviductal mucosa of Xenopus laevis, an amphibian characterized by external fertilization. In particular we examined the expression and localization of Interleukin-1β (IL1B), Macrophage migration inhibitory factor (MIF) and Interleukin-1 receptor type 1 (IL1R1) in different oviductal portions including an upper glandular region, an intermediate and a lower aglandular region (the ovisac). Tissues were examined by immunohistochemistry and western blot using polyclonal antibodies against human molecules. IL1B, MIF and IL1R1 were all shown in the three oviductal regions examined, albeit with a general increase towards the external environment. A substantial difference among the cytokine components was also observed mainly in the epithelium of the glandular and intermediate regions. Specifically, all three molecules were expressed by the luminal ciliated cells while only IL1R1 was present in the unciliated cells at the bottom of the epithelial ingrowths. The expression of IL1R1 in these cells appeared as a continuous layer separating the epithelium from the underlying tissues. While supporting the role of the innate immune system for hosts defense against pathogens, the peculiar distribution of the cytokine components in the oviduct of X. laevis suggests novel immunologic strategies useful to assure gland secretion essential for egg formation and fertilization.

Genetic diversity in the Carabodes marginatus species group (Acarida, Oribatida, Carabodidae) as inferred from allozymes

Ten populations representing four species of the ‘Carabodes marginatus’ group, as C. marginatus, C. affinis, C. quadrangulus and C. montanus from central Italy have been studied for genetic variation at 16 enzymatic loci by electrophoresis. Morphotypes close to C. marginatus but easily distinguishable by the shorter marginal notogastral setae were also included in the analysis to evaluate their systematic status. Carabodes arduinii, a very different species from the ‘coriaceus’ group, was employed as an out-group. Phylogenetic relationships among different species were studied and inferred data demonstrated that cladogenetic events occurred, even though rates of molecular and morphological evolution do not correlate. Morphotypes related to C. marginatus were genetically very close to the type specimens, but a different pattern of allele frequency was observed in sympatric populations of the two setal forms. Possible explanations for this finding are suggested in relation to historical processes. The rate of gene flow among populations of the two morphs was estimated by both Wrights F st and Slatkins Nm methods. These two different procedures yielded contradictory results.