Massimo Trentini

Sand flea (Tunga spp.) infections in humans and domestic animals: state of the art

Tungiasis is a parasitic disease of humans and animals caused by fleas (Siphonaptera) belonging to the genus Tunga. Two species, Tunga penetrans (L.) and Tunga trimamillata, out of 10 described to date, are known to affect man or domestic animals; the other eight are exclusive to a few species of wild mammals. Tunga penetrans and T. trimamillata originated from Latin America, although the first species is also found in sub‐Saharan Africa (between 20° N and 25° S). Hundreds of millions of people are at risk of infection in more than 70 nations, mostly in developing countries. The second species has been reported only in Ecuador and Peru. Males and non‐fertilized females of Tunga are haematophagous ectoparasites; pregnant females penetrate the skin where, following dilatation of the abdomen, they increase enormously in size (neosomy) and cause inflammatory and ulcerative processes of varying severity. The importance of Tunga infection in humans concerns its frequent localization in the foot, which sometimes causes very serious difficulty in walking, thereby reducing the subjects ability to work and necessitating medical and surgical intervention. Tungiasis in domestic animals can be responsible for economic losses resulting from flea‐induced lesions and secondary infections. Because tungiasis represents a serious problem for tropical public health and because of the recent description of a new species (Tunga trimamillata), it seems appropriate to review current knowledge of the morphology, molecular taxonomy, epidemiology, pathology, treatment and control of sand fleas of the genus Tunga.

Ultrastructural observations on the oogenesis of Triops cancriformis (Crustacea, Notostraca).

SummaryEach ovarian follicle of Triops cancriformis is four-celled; these cells (one oocyte and three nurse cells) are interconnected by cytoplasmic bridges. In the course of differentiation, the nurse cells are early recognizable; they increase in size more than the oocyte and their nuclei contain many nucleoli. For the first time in Arthropoda, yolk globules are reported to be present in nurse cell cytoplasm; these globules arise from the smooth endoplasmic reticulum. The functional significance of the intercellular bridges and the trophic role of the nurse cells are discussed.

FOLLICLE DUCT CELL ULTRASTRUCTURE AND EGGSHELL FORMATION IN TRIOPS CANCRIFORMIS (CRUSTACEA, NOTOSTRACA)

Electron microscopy of the cells of the follicle duct of Triops cancriformis shows that the follicular ducts are lined by a single‐layered epithelium which also produces the eggshell material. The cytoplasm is rich in rough endoplasmic reticulum that synthesizes the eggshell material which subsequently aggregates into preformed vacuoles. Newly formed spheres of eggshell material are then excreted into the lumen. At the end of vitellogenesis the oocytes descend toward the longitudinal oviduct and pass through the eggshell material which fills the follicle ducts. The production of the eggshell and its chemical composition in some Phyllopoda are compared. The paper discusses the relationship between the eggshell construction and the reproductive biology of the population.

Genetic variability of Tunga penetrans (Siphonaptera, Tungidae) sand fleas across South America and Africa

Tunga penetrans is a widely distributed sand flea, infecting men and domestic animals. It originated in South America, but it is now also endemic of Sub-Saharan Africa due to a recent accidental introduction. Previous genetic analyses indicated a very limited variability in the Ecuadorian populations; on the other hand, samples from Madagascar resulted to be genetically isolated. To better examine the genetic variability of T. penetrans, a wider sampling was analysed for mitochondrial (cytochrome oxidase II) and nuclear (ribosomal internal transcribed spacer [ITS] 2) DNA sequences. The mitochondrial marker confirms the low genetic variability, with few haplotypes characterizing the majority of individuals from different populations. Haplotype distribution is in agreement with a recent colonization of Africa and with a rapid spreading across this continent. Moreover, a consistent gene flow between the Pacific and Atlantic South American populations emerges, possibly due to human and/or animal cross-Andean dispersal. On the other hand, the ITS2 marker depicts a sharply diverging pattern with samples collected in Ecuador unequivocally distinguished from the Brazilian and African ones. On the whole, taking into account also the molecular features of the marker used, data here presented are better interpreted in the light of a high dispersal ability of T. penetrans, probably reducing the phylogeographic signal.

The bivalve mollusc Mactra corallina:genetic evidence of existing sibling species

The rayed trough-shell Mactra corallina Linnaeus 1758 is a surf clam that inhabits the Atlantic Ocean, Black Sea and Mediterranean Sea and represents a commercially important bivalve. This species is present with two different and well-defined sympatric morphotypes, which differ mainly for the colour of the shell (white in the corallina morph, and brown-banded in the lignaria morph). The aim of this work is to resolve the confused and contradictory systematics of the bivalves belonging to M. corallina putative species by analysing molecular and morphological features. Fifteen specimens of M. corallina corallina (white variant) and 19 specimens of M. corallina lignaria (brown variant) were collected in the North Adriatic Sea and analysed by four molecular markers (12S, 16S, 18S and COI genes, partial sequences). Genetic analyses clearly support the presence of two different species, which were previously ascribed to M. corallina. In addition, 35 specimens identified on a morphological basis as M. c. corallina and 28 specimens identified as M. c. lignaria collected in the same area were used for a morphometric analysis. A positive correlation was found between the maximum width of shell (W), anteroposterior length and between W and the height of specimens from umbo to ventral margin, thus adding to molecular data.

A chromosomic study of Chamelea gallina (L.) (Bivalvia, Veneridae)

Abstract The chromosome complement of Chamelea gallina is n = 19 and 2n = 38. In both males and females meiosis shows chiasmata. Karyotype mainly contains submetacentric and metacentric chromosomes. No heterotypic or supernumerary chromosomes result from the analysis of meiotic and of mitotic chromosomes.

The Chromosomes of Idotea Balthica Basteri Audouin (Isopoda, Valvifera)

[La garniture chromosomique de Idotea balthica basteri Audouin dans tous les deux sexes est n = 29, 2n = 58. La plupart des chromosomes sont metacentriques ou submetacentriques. Toutes les C-metaphases spermatogoniales montrent un chromosome metacentrique avec un segment heteropycnotique negatif. Dans la prophase de la premiere division meiotique femelle les chromosomes bivalents presentent une phase de despiralisation., La garniture chromosomique de Idotea balthica basteri Audouin dans tous les deux sexes est n = 29, 2n = 58. La plupart des chromosomes sont metacentriques ou submetacentriques. Toutes les C-metaphases spermatogoniales montrent un chromosome metacentrique avec un segment heteropycnotique negatif. Dans la prophase de la premiere division meiotique femelle les chromosomes bivalents presentent une phase de despiralisation.]

Novel PCR-based assay for rapid identification of Red Fluorescent Proteins in GloFish and GloFish x wildtype zebrafish (Danio rerio) hybrids

Abstract Twenty-five zebrafish presenting three different colour variants were collected and analysed by molecular markers in order to define their species and to verify if the unusual colouration presented by two morphotypes was due to genetic engineering or were natural colour variants obtained by selective breeding or spontaneous mutations. The three morphotypes collected were (a) an unusual reddish-pink (suspected red GloFish®), 15 specimens confiscated by the operative ecological core of police officers; (b) the black/blue striped colouration typical of wildtype Danio rerio (five specimens) and (c) an hybrid morphotype with an atypical flashing red pigmentation of skeletal muscle and a blue-black striped pigmentation of skin (five specimens obtained by crossing suspected GM danios with wildtype line) obtained by crossing wild type danios with fish confiscated by police. Despite the three different colourations presented, all analysed samples were unequivocally Danio rerio, excluding the possibility of belonging to different species or natural variants, which should carry different skin colours. Except the five wild-type danios, all other samples analysed should belong to an engineered variant and thus forbidden by EU GMO legislation. Here we designed a new highly reliable and affordable PCR-based assay able to identify the presence of red fluorescent proteins not only in the 15 parental GM samples but also in the five F1 hybrids created ad hoc. The cross-breeding experiment clearly demonstrated that the exogenous construct made by red fluorescent protein under a fast-muscle promoter was inherited by F1. For this reason in our opinion also cross-hybrids obtained by GM danios and wildtype zebrafish should be included in the list of organisms regulated by GMO legislation. Finally, the obtained results suggest that the PCR-based assay here implemented could represent a cost-effective test to rapidly identify suspected GM fish, which carry RFP/dsRED isoforms.