The Sertoli cell in lizards

Sertoli cells of lizards are characterized by variable size, abundant smooth and rough endoplasmic reticulum, multivesicular bodies, lipid vacuoles probably related to the spermatogenic cycle, and mitochondria of normal size. The cytoskeleton contains actin, particularly abundant in the cell periphery, vimentin all around the nucleus and throughout the rest of the cytoplasm. Moreover, microtubules are distributed in the cell periphery. The junctional complexes demonstrate the presence of a very efficient blood-testis barrier, containing tight, gap, tight-gap, septate-like, desmosome-like, and "Sertoli-Sertoli" junctions. In the last, the actin layer interposed between the plasma membrane and the subsurface cistern is absent. The desmosome-like junctions are surrounded by 7-nm filaments and not by intermediate filaments.     

Actin filaments and mitochondrial movement in vertebrate spermiogenesis

The presence of actin filaments around mitochondria during vertebrate spermiogenesis was demonstrated by immunofluorescence and immuno-electron microscopy and by heavy meromyosin decoration. The presence of actin is supposed to be related to mitochondrial rearrangements occurring in the spermatid stage.     

The secret of Pianosa island: an Italian native population of European brown hare (<Emphasis Type="Italic">Lepus europaeus meridiei</Emphasis> Hilzheimer, 1906)

Given its relevance as a game species, the brown hare (Lepus europaeus Pallas, 1778) is one of the most managed and translocated mammals in Europe. In Italy, the species shows a genepool consisting of a mix of native and exotic lineages, due to translocations and introductions for hunting purposes. Some authors argued that the introduction of exotic brown hares could have caused the extinction of an endemic subspecies, L. e. meridiei Hilzheimer 1906, once present in central and northern Italy. Here we genetically characterized for the first time the brown hare population living in Pianosa island (part of the Tuscan Archipelago National Park) using 13 STR loci and a fragment of the mtDNA control region. All individuals analyzed share a unique haplotype, the L. europaeus haplotype Leu2, recognized as the ancestral mitochondrial lineage corresponding to the subspecies L. e. meridiei. Furthermore, considering autosomal markers, Pianosa brown hare population and current Italian peninsular population are genetically distinct. The discovery of this ancient population in a protected area, isolated and not affected by recent translocation/restocking events, has a great relevance in conservation and confirms the current presence of the endemic subspecies L. e. meridiei in Italy.     

Immotile,aflagellate spermatozoa in Ptiliidae coleopterans

The first aflagellate and immotile Coleopteran spermatozoon is described in a group of species belonging to the family Ptiliidae. The mature spermatozoon is devoid of flagellum, centrioles and mitochondria, includes a three-layered acrosomal complex (extraacrosomal layer, acrosome and perforatorium) and a long nucleus made up of two regions of different densities. A compact submembranary capsule and a thick glycocalyx are also present. Motility organelles are absent during the whole spermiogenesis, which is not regressive. The new structures peculiar for this type of sperma are designed for protection. No other sperm models with these characteristics have been described so far.     

L'ultrastruttura delle ghiandole della ooteca in Ortotteri Acridoidei,Blattoidei e Mantoidei

Riassunto La presente ricerca ultrastrutturistica è stata condotta sulle ghiandole che secernono l'ooteca nella femmina degli Ortotteri Acridoidei, dei Blattoidei e dei Mantoidei. Questi tre gruppi sono i soli, fra gli Ortotteroidei, che secernono ooteche indurite e complesse, ma mentre nei Blattoidei e Mantoidei alla secrezione presiedono le primitive ghiandole colleteriche, che sboccano nell'ovidutto impari, negli Acridoidei, che sono di più recente comparsa e (fra gli Ortotteri) i più recentemente evoluti, la secrezione è opera di due diverticoli degli ovidutti pari (ghiandole pseudocolleteriche) che sostituiscono le vere colleteriche perdute lungo la filogenesi dell'ordine Orthoptera. La ultrastruttura delle ghiandole pseudocolleteriche è infatti quella di un tipico organo di recente acquisizione: le due ghiandole sono uguali fra loro, e composte di cellule simili per la intera lunghezza, che secernono tutti i prodotti costituenti l'ooteca: enzimi, proteine strutturali, polisaccaridi.Le due ghiandole colleteriche degli Ortotteroidei più antichi, i Blattoidei, sono invece diverse fra di loro: la sinistra differenzia due tratti secretori: uno ricco di ergastoplasma (che elabora proteine strutturali) ed uno di mitocondri (che elabora una fenolossidasi); la destra pure due tratti, uno con prevalente ergastoplasma (secretore di -glucosidasi) ed uno con abbondanti Golgi e granuli glucidici (elaboratore di un polisaccaride).Nei Mantoidei vi sono 5 ghiandole: una coppia, costituite da numerosi tubuli, che elaborano, da un abbondante ergastoplasma, un secreto protidico e glucidico; una seconda coppia (ramificate e suddivise ciascuna in due diversi tratti) che secernono a monte una ossidasi (sono simili al tratto ricco di mitocondri della sinistra di Periplaneta) e a valle una glucosidasi (sono simili al tratto ricco di ergastoplasma della destra di Periplaneta). La quinta ghiandola, impari, ha i caratteri degli organi secretori di glucidi e protidi e secerne Calcio che viene aggiunto al secreto.

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Summary This paper deals with the ultrastructure of the glands that secrete the ootheca in the female of three groups of the super order Orthopteroidea: Acridoidea, Blattoidea and Mantoidea. Among the Orthopteroidea these three are the only groups that secrete hardened and complex oothecae. Whereas in the Blattoidea and Mantoidea they are secreted by the primitive colleterial glands that open into the unpaired oviduct, in the more recently evolved Acridoidea the secretion is the product of two loops of the paired oviducts (pseudocolleterial glands). These take the place of the colleterial glands lost in the phylogeny of the order. In fact, the ultrastructure of pseudocolleterial glands is typical of recently acquired organs. The two glands are alike and are composed of the same type of cells throughout. These cells secrete all the products that make up the ootheca: enzymes, structural proteins, and polysaccharides.The two colleterial glands of the most ancient of these three groups of Orthopteroidea, the Blattoidea, are diverse. In the left-hand one, zones can be differentiated. One, rich in ergastoplasm, produces structural proteins and the other, rich in mitochondria, produces a phenoloxidase. The gland on the right also consists of zones: one, rich in ergastoplasm, that secretes -glucoxidase, and the other, with abundant Golgi elements and glucidic granules, that elaborates a polysaccharide.In the Mantoidea there are five glands. One pair is made up of numerous tubules that produce a glucidic and proteinaceous secretion from copious ergastoplasm. In a second pair each gland is branched and subdivided into two diverse parts. The zone at the origin of the gland (like the left-hand zone of Periplaneta rich in mitochondria) secretes an oxidase, whereas the distal portion (like the right-hand zone of Periplaneta, rich in ergastoplasm) secretes a glucoxidase. The fifth gland, unpaired, has the characteristics of an organ that elaborates carbohydrates and proteins and releases calcium, which is added to the secretion.

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Research performed under C.N.R. contract.     

Invasive rats and seabirds after 2,000 years of an unwanted coexistence on Mediterranean islands

In the Mediterranean, the survival of endemic long-lived seabirds despite the long-standing introduction of one of the most damaging alien predator, the ship rat (Rattus rattus), on most islands constitutes an amazing conservation paradox. A database gathering information on approximately 300 Western Mediterranean islands was analyzed through generalized linear models to identify the factors likely to influence ship rat presence and to account for how ship rat presence and island characteristics may have driven the presence and abundance of seabirds. Our review showed that few Mediterranean islands remain rat-free. At the regional scale, rat presence was only a limiting factor in the abundance of the smallest seabird, the storm petrel (Hydrobates pelagicus), while the distribution and abundance of the three shearwaters were more influenced by island characteristics. We hypothesized that the long-term persistence of these seabirds may have been facilitated by the various biogeographical contexts of Mediterranean islands, likely to provide intra-island refuges.     

Establishing the eradication unit of Molara Island: a case of study from Sardinia, Italy

Molara is a small island belonging to the Marine protected Area Tavolara—Punta Coda Cavallo, in Sardinia. During 2006–2007, a bio-monitoring program reported a strong presence of the black rat, Rattus rattus, on Molara island. Rat predation has detrimentally affected the unique biodiversity of this island, thus, in 2008 an eradication campaign was conducted. Our eradication protocol included a pre-eradication genetic investigation, using 8 microsatellite loci, on a rat population of Molara as well as on neighbour islands within the Marine Protected Area (MPA). The main goal of this genetic investigation was to establish the correct borders of the eradication unit of Molara island. As several recent eradication campaigns have been unsuccessful, due to incomplete and unstable eradication, we also aimed to assess possible hidden sources of reinvasion. Specimens were also collected during post- eradication monitoring on Molara for genetic screening to establish their origin, and thus validate the effectiveness of our eradication campaign. According to our genetic analysis, within the MPA there are four different eradication units, corresponding to the islands of Molara, Tavolara, Piana and to the Sardinia mainland. Gene flow among these four units is more or less absent. The assignment and clustering tests performed on pre and post-eradication samples seem to indicate that the population of Sardinia mainland is a possible source of re-invasion for the Piana and Molara populations.