Search results for "Gastropod"
showing 10 items of 95 documents
Experimental Testicular Torsion: Effect on Endocrine and Exocrine Function and Contralateral Testicular Histology
1988
In order to investigate whether unilateral testicular torsion exerts a negative influence on the previously undisturbed contralateral side, exocrine and endocrine testicular function were evaluated before and two months after torsion. A rat model with 6 hours', 12 hours' or permanent extravaginal 540 degrees torsion of the right testis was used; a sham operated group of animals served as controls. Ejaculates were collected by electrostimulation; LH, FSH and testosterone serum levels were determined by radioimmunoassays. Eight weeks after torsion sperm output had decreased by half in the experimental groups, and LH levels increased significantly, whereas the other hormone levels, as well as …
Spermiogenesis in the vermetid gastropod Dendropoma petraeum (Gastropoda, Prosobranchia)
2002
The structure and maturation of the male gonad of the Mediterranean vermetid gastropod Dendropoma petraeum are described. Histological sections of the gonads were made throughout development and gonad activity was monitored at regular monthly intervals. During the autumn months the gonad is very small and is surrounded by a large quantity of connective tissue; it becomes more voluminous from December to August, with the highest growth peak in springtime. The stages of spermatogenesis were also observed and described.
DNA multigene sequencing of topotypic specimens of the fascioliasis vector Lymnaea diaphana and phylogenetic analysis of the genus Pectinidens (Gastr…
2012
Freshwater lymnaeid snails are crucial in defining transmission and epidemiology of fascioliasis. In South America, human endemic areas are related to high altitudes in Andean regions. The species Lymnaea diaphana has, however, been involved in low altitude areas of Chile, Argentina and Peru where human infection also occurs. Complete nuclear ribosomal DNA 18S, internal transcribed spacer (ITS)-2 and ITS-1 and fragments of mitochondrial DNA 16S and cytochrome c oxidase (cox)1 genes of L. diaphana specimens from its type locality offered 1,848, 495, 520, 424 and 672 bp long sequences. Comparisons with New and Old World Galba/Fossaria, Palaearctic stagnicolines, Nearctic stagnicolines, Old Wo…
European Lymnaeidae (Mollusca: Gastropoda), intermediate hosts of trematodiases, based on nuclear ribosomal DNA ITS-2 sequences.
2001
Freshwater snails of the family Lymnaeidae are of a great parasitological importance because of the very numerous helminth species they transmit, mainly trematodiases of large medical and veterinary impact. The present knowledge on the genetics of lymnaeids and on their parasite-host inter-relationships is far from being sufficient. The family is immersed in a systematic-taxonomic confusion. The necessity for a tool which enables species distinction and population characterization is evident. This paper aims to review the European Lymnaeidae basing on the second internal transcribed spacer ITS-2 of the nuclear ribosomal DNA. The ITS-2 sequences of 66 populations of 13 European and 1 North A…
DNA Multi-Marker Genotyping and CIAS Morphometric Phenotyping of Fasciola gigantica-Sized Flukes from Ecuador, with an Analysis of the Radix Absence …
2021
Simple Summary Fasciolid flukes collected from sheep and cattle in Ecuador showed a high diversity in DNA sequences whose analyses indicated introductions from South America, European and North American countries. These results agree with the numerous livestock importations performed by Ecuador. Abnormally big-sized liver flukes were found in Ecuadorian sheep. The morphometric phenotypic CIAS study showed that its size maximum and mean very pronouncedly and significantly surpassed those of the Fasciola hepatica populations from South America and Spain and proved to be intermediate between standard F. hepatica and F. gigantica populations. Such a feature is only known in intermediate fasciol…
Cupredoxin-like domains in haemocyanins
2010
Haemocyanins are multimeric oxygen transport proteins, which bind oxygen to type 3 copper sites. Arthropod haemocyanins contain 75-kDa subunits, whereas molluscan haemocyanins contain 350–400-kDa subunits comprising seven or eight different 50 kDa FUs (functional units) designated FU-a to FU-h, each with an active site. FU-h possesses a tail of 100 amino acids not present in the other FUs. In the present study we show by X-ray crystallography that in FU-h of KLH1 (keyhole-limpet-haemocyanin isoform 1) the structure of the tail domain is cupredoxin-like but contains no copper. The copper-free domain 3 in arthropod haemocyanin subunits has also recently been reinterpreted as being cupredoxin-…
Structure of Mega-Hemocyanin Reveals Protein Origami in Snails
2014
SummaryMega-hemocyanin is a 13.5 MDa oxygen transporter found in the hemolymph of some snails. Similar to typical gastropod hemocyanins, it is composed of 400 kDa building blocks but has additional 550 kDa subunits. Together, they form a large, completely filled cylinder. The structural basis for this highly complex protein packing is not known so far. Here, we report the electron cryomicroscopy (cryo-EM) structure of mega-hemocyanin complexes from two different snail species. The structures reveal that mega-hemocyanin is composed of flexible building blocks that differ in their conformation, but not in their primary structure. Like a protein origami, these flexible blocks are optimally pac…
The Sequence of a Gastropod Hemocyanin (HtH1 from Haliotis tuberculata)
2000
The eight functional units (FUs), a-h, of the hemocyanin isoform HtH1 from Haliotis tuberculata (Prosobranchia, Archaeogastropoda) have been sequenced via cDNA, which provides the first complete primary structure of a gastropod hemocyanin subunit. With 3404 amino acids (392 kDa) it is the largest polypeptide sequence ever obtained for a respiratory protein. The cDNA comprises 10,758 base pairs and includes the coding regions for a short signal peptide, the eight different functional units, a 3'-untranslated region of 478 base pairs, and a poly(A) tail. The predicted protein contains 13 potential sites for N-linked carbohydrates (one for HtH1-a, none for HtH1-c, and two each for the other si…
Land molluscs from the Isola delle Femmine Nature Reserve (north-western Sicily, Italy) (Gastropoda Architaenioglossa Pulmonata)
2021
The results of a study on the fauna of land molluscs from Isola delle Femmine Nature Reserve (NW Sicily, Italy) (Gastropoda Architaenioglossa Pulmonata) are here described. In this small island 23 species have been found, 6 of which are Sicilian endemic taxa. Siciliaria leucophryna microinsularis n. ssp. endemic to the Isola delle Femmine (or Isola di Fuori) is described. For each species ecological, distributional data and information on their presence on this island are provided.
Geometric Measurement Analysis Versus Fourier Series Analysis for Shape Characterization Using the Gastropod Shell (Trivia) as an Example
2003
Varied and efficient methods have been developed to describe and quantify natural objects. The most common ones use superimposition techniques (e.g. Procrustes methods; Bookstein, 1991), decomposition into harmonics (Fourier series and functions, wavelets; Anstey and Delmet, 1973; Christopher and Waters, 1974; Gevirtz, 1976; Lestrel, 1997; Toubin and others, 1999; Verrecchia, Van Grootel, and Guillemet, 1996; Younger and Ehrlich, 1977), analysis of spiral functions (e.g. Raup parameters; Raup, 1961, 1966; Tursch, 1998), and combinations of parameters from elementary geometry (e.g. circularity index, lengthening; Coster and Chermant, 1989; Schmidt-Kittler, 1986; Viriot, Chaline, and Schaaf, …