Search

Gnathostomiasis is a fish-borne zoonotic infection caused by eating infected seafood or fish parasitized by third-stage nematode larvae of the genus Gnathostoma. Twenty-seven fish specimens of the European eel Anguilla anguilla (Anguillidae) were collected from water coasts of the Mediterranean Sea in Egypt. Of the 27 fish that were studied, 14 fish (51.58%) were parasitized with third-stage larvae (L3) of Gnathostoma sp. (Gnathostomatidae), these larvae were investigated as encapsulated on the surface of different visceral organs and some embedded in muscles of the infected fish. By using both light and scanning electron microscopes, the morphological examination of the recovered nematodes revealed that the main diagnostic features represented by an elongated body, measured 6.5±2 (7.8-9) mm long, and its greatest width observed at the posterior one-third of the body was 0.4±0.02 (0.38-0.44) mm with narrow lateral alae, the presence of a cephalic bulb measured 0.26±0.02 (0.18-0.28) mm long, 0.31±0.02 (0.28-0.34) wide and armed with six transverse rows of spines, mouth opening surrounded by two simple lateral lips, and conical tail terminated with a pointed mucron. The described species was morphologically and morphometrically compared with some of the previously recorded species of the same genus. Based on our detailed description, the present species was identified as Gnathostoma sp. recovered from A.anguilla as the first record in Egypt. [ABSTRACT FROM AUTHOR]

The microstructures of the carapaces of the spider crabs Schizophrys dahlak and Hyastenus hilgendorfi were examined under both scanning and transmission electron microscopes. Image analyses of the cross-sectioned carapaces showed that both species have a hierarchical microstructure with three well-defined layers. The two innermost layers (exocuticle and endocuticle) consist of stacked fibers arranged in a twisted plywood fashion producing a "Bouligand structure". They have a similar structure but different thicknesses and height of the stacks. The cuticles are inter-stitched with pore canals of varying width between the studied species, running transversely to the layered structure. This variation in the width of the pore canals in the two species seems to be proportional to the size of the carapace and its surface area. [ABSTRACT FROM AUTHOR]

The present study is an approach to investigate the chromosomal pattern of Biomphalaria alexandrina snails. This may be useful for breaking the hostparasite relationship, which is very specific and dependable on the genetic (chromosomal) status of these hosts. Freshwater snails are essential for the transmission of schistosomiasis by acting as intermediate hosts for the diseasecausing parasite. The objective of this study clarifies the four meiotic divisions that begin with Interphase, prophase, metaphase, and anaphase by Transmission Electron Microscope (TEM) and measuring the lengths of chromosomes by Scanning Electron Microscope (SEM). Results showed the number of the chromosomes of B. alexandrina snails N=18, 2N=36 including 4 types of chromosomes, 5 metacentric pairs, 4 submetacentric pairs, 3 acrocentric pairs, and 6 telocentric pairs chromosomes, they were arranged in a descending manner according to the total length that between 12-2 µm. Notably, the present work is the first chromosomal study of B. alexandrina snails by using TEM and SEM. So high-resolution SEM has proven to be a useful tool for chromosomal study. [ABSTRACT FROM AUTHOR]

A new record of Lamproglenine copepods, Lamproglena pulchella were collected from the gills of cyprinid freshwater fish Leuciscus vorax from the Tigris River, Iraq in order to investigate the morphological and functional characteristics of their appendages using scanning electron microscope. A maxilliped appears robust, and bears at its apex two subequal curving, claw-like spines. First legs were with a small protuberance on medial margin of the sympod near the base; endopod apparently unsegmented, exopod indistinctly two-segmented, with several setae on lateral margin and single stout seta on apex. Second legs have two segmented rami; endopod unarmed and exopod with single seta on lateral margin of basal segment and three setae at apex. Third and fourth pairs of appendages were similar, with alike rami and with only two setae at the apex of exopod. These appendages are thought to serve as a holdfast for attachment on the gill filament of the tigris fish. Cuticular differentiations found on the body surface of L. pulchella play a secondary role in the attachment of the copepod on its host. Current study microscopy shows that the maxillae of L. pulchella are characteristically prehensile and thus provides an efficient tool for the attachment to the host tissue. [ABSTRACT FROM AUTHOR]