Search results for "Excretory system"
showing 10 items of 12 documents
Ovicide-induced serosa degeneration and its impact on embryonic development in Manduca sexta (Insecta: Lepidoptera)
2003
Abstract Eggs of Manduca sexta treated with the ovicide Ov. 165049 turn orange, and the embryos later die. The orange pigmentation is at first confined to the serosa, and is accompanied by pathological changes of serosal cells. Lipid vesicles aggregate and spindle-shaped electron-lucent vesicles—normally forming a single layer below the apical cell surface—greatly accumulate. The mitochondria swell considerably, and their matrices become electron-lucent. Subsequently, the serosal cells develop additional features of necrosis. They form many autophagic vacuoles which contain mostly degradating mitochondria, but also segregated rough endoplasmic reticulum (rER) and glycogen granules. The whol…
The pronephros of the early ammocoete larva of lampreys (Cyclostomata, Petromyzontes): Fine structure of the renal tubules
1991
The renal tubules of the paired pronephros in early larvae (ammocoetes) of two lamprey species, Lampetra fluviatilis and Petromyzon marinus, were studied by use of light-, scanning- and transmission electron microscopy. They consist of (1) a variable number of pronephric tubules (3 to 6), and (2) an excretory duct. By fine-structural criteria, the renal tubules can be divided into 6 segments. Each pronephric tubule is divided into (1) the nephrostome and (2) the proximal tubule, the excretory duct consisting of (3) a common proximal tubule followed by (4) a short intermediate segment, and then by a pronephric duct composed of (5) a cranial and (6) a caudal section. The epithelium of the nep…
Echinostoma caproni: identification of enolase in excretory/secretory products, molecular cloning, and functional expression.
2007
In order to investigate molecules that could be involved in host-trematode relationships, we have analysed the excretory/secretory products (ESP) of Echinostoma caproni following a proteomic approach. Actin, Gluthathione S-transferase (GST) and enolase have been identified in the ESP. Enolase, observed to be one of the most abundant proteins, was further characterized. The molecular cloning and in vitro expression in Escherichia coli of E. caproni enolase allowed us to determine that the protein contains 431 amino acids and a theoretical MW of 46272 Da. E. caproni enolase shows high homology to other trematode enolases. The recombinant protein binds specifically to human plasminogen in vitr…
An experimental study of the reproductive success of Echinostoma friedi (Trematoda: Echinostomatidae) in the golden hamster
2003
Viable eggs produced weekly per infective stage was used as a measure of the reproductive success of Echinostoma friedi during the first 12 weeks of infection in hamsters. The weekly reproductive success was not constant during the experiment in relation to the egg output and the proportion of viable eggs produced. The egg release started during week 2 post-inoculation, attaining a maximum during week 3. A decline in egg output was observed from week 9. Viable eggs were only produced from week 3 post-inoculation and a maximum was attained at week 4 of the experiment. A decline in egg viability was observed from week 9. Considering together the egg output and the egg viability, the maximum w…
Ultrastructure of embryonic envelopes and integument ofOncopeltus fasciatus dallas (Insecta, Heteroptera)
1978
The embryo ofOncopeltus fasciatus forms a typical secondary dorsal organ (SDO). It develops after katatrepsis from the contracting serosa, the cells of which decrease in diameter but increase considerably in height. After 66 h, the SDO represents a protrusion of the serosal epithelium above the head and is then reduced to a disc-shaped formation, which sinks into the yolk, where it disintegrates after 80 h. During its typical expression, between 66 and 78 h, the SDO shows a zonal arrangement of its cell organelles. The nucleus, which is located in the basal cell region, has a very irregular outline and includes several nucleoli and globular inclusion bodies. Rough and smooth ER are well dev…
Leucine aminopeptidase is an immunodominant antigen of Fasciola hepatica excretory and secretory products in human infections.
2007
ABSTRACT The liver fluke Fasciola hepatica parasitizes humans and ruminant livestock worldwide, and it is now being considered a reemerging zoonotic disease, especially in areas in which it is endemic, such as South America. This study investigates the immune response to excretory and secretory products produced by F. hepatica in a group of patients from the Peruvian Altiplano, where the disease is highly endemic. Using a proteomic approach and immunoblotting techniques, we have identified the enzymes leucine aminopeptidase (LAP) and phosphoenolpyruvate carboxykinase as immunodominant antigens recognized by sera from fasciolosis patients. An indirect enzyme-linked immunosorbent assay using …
Redescription and phylogenetic analysis of the type species of the genus Panagrellus Thorne, 1938 (Rhabditida, Panagrolaimidae), P. pycnus Thorne, 19…
2021
Abstract The identity of Panagrellus pycnus, the type species of the genus Panagrellus, is discussed after studying specimens from a cultured population collected in Italy that fits the original material of the species. A new characterization is consequently provided as follows: body 0.93–1.32 mm long, lip region continuous with the adjoining body, stoma with gymnostom very reduced, pharynx with not swollen metacorpus, neck 161–203 µm long, excretory pore at level of the metacorpus, post-vulval uterine sac 99–162 µm long or 2.6–3.8 times as long as the body diameter divided in a short tubular proximal part and a long swollen distal part, vulva post-equatorial (V = 63–69), female tail conica…
Definitive host influences the proteomic profile of excretory/secretory products of the trematode Echinostoma caproni
2016
Background Echinostoma caproni is an intestinal trematode extensively used as experimental model for the study of factors that determine the course of intestinal helminth infections, since this markedly depends on the host species. Although the host-dependent mechanisms for either chronic establishment or early parasite rejection have been broadly studied, little is known regarding the parasite response against different host environments. Methods To identify host-dependent differentially expressed proteins, a comparative proteomic analysis of the excretory/secretory products released from E. caproni adults, isolated from hosts displaying different compatibility with this trematode, was per…
Identification of enolase as a plasminogen-binding protein in excretory-secretory products ofFasciola hepatica
2004
AbstractWe have followed a combined proteomic approach to identify proteins of Fasciola hepatica that could be involved in host–parasite interactions. Using two-dimensional gel electrophoresis, far Western immunoblot and mass spectrometry analyses, we have identified the enolase enzyme, present in the excretory/secretory materials of F. hepatica, as a human plasminogen-binding protein. This enzyme has an apparent molecular weight of 47 kDa with pI ranging from 6.2 to 7.2. These results suggest that enolase could act as a plasminogen receptor.
Extracellular vesicles from parasitic helminths contain specific excretory/secretory proteins and are internalized in intestinal host cells.
2012
The study of host-parasite interactions has increased considerably in the last decades, with many studies focusing on the identification of parasite molecules (i.e. surface or excretory/secretory proteins (ESP)) as potential targets for new specific treatments and/or diagnostic tools. In parallel, in the last few years there have been significant advances in the field of extracellular vesicles research. Among these vesicles, exosomes of endocytic origin, with a characteristic size ranging from 30-100 nm, carry several atypical secreted proteins in different organisms, including parasitic protozoa. Here, we present experimental evidence for the existence of exosome-like vesicles in parasitic…