أ.د/علاء يسري مصطفي

Professor - Professor of invertebrates and marine toxins

Faculty of science

Address: Zoology Department -Faculty of Science


Distribution and morphology of defensive acid-secreting glands in Nudipleura (Gastropoda: Heterobranchia), with an emphasis on Pleurobranchomorpha.
Secretion of acidic substances with defence and repellent properties is known in several metazoan taxa, including Gastropoda. Here we investigate and compare defensive acid-secreting cell types of various genera within the heterobranch taxon Pleurobranchomorpha by analysing the sizes and distribution of the secretory epithelial cells and subepithelial glands of the epidermis. Additionally, we investigate the median buccal gland (MBG), which ... Read more

The ontogeny of appendages and carapace of Neonesidea schulzi (Ostracoda: Bairdiidae) from the Red Sea coast, Egypt
The ostracod genus _Neonesidea _is broadly distributed in shallow marine waters. The ontogeny of the _N. schulzi _(Bairdiidae) is described in detail by studying the development of the appendages and variations in carapace form, size and structure. _Neonesidea schulzi _has eight post-embryonic instars, and a gap in its ontogenetic development during instar A-6, where no new _Anlage _is added. The ... Read more

Assessment of Biochemical and Histopathological Effects of Crude Venom of Cone Snail Conus flavidus on albino Mice
The genus Conus is equipped with a unique venomous mixture of conopeptides which secreted for predation and defense purposes. This work is aiming to explore and determine the effect of the crude venom of Conus flavidus, a wormhunting cone snail inhabiting the Red Sea, on the oxidant/ antioxidant system in mice using some oxidative stress biomarker assays. In addition to ... Read more

A review of the genus Berthellina (Mollusca: Heterobranchia: Pleurobranchidae) in the Red Sea based on molecular and anatomical data
The genus _Berthellina_ Gardiner 1936 (Mollusca: Heterobranchia: Nudipleura) is a circumtropical group of pleurobranchid sea slugs including species with uniform coloration patterns, varying from yellow and orange to red. The systematics of Berthellina is in need of a revision for many areas of the world, particularly in the Indo-West Pacific region, where more than one species seem to occur. In ... Read more

Immunotoxicity of skin acid secretion produced by the sea slug Berthellina citrina in mice spleen: Histological and Immunohistochemical study
Acid secretion containing sulfuric and hydrochloric acids is a fascinating defensive phenomenon within many groups of marine organisms. This study aimed to investigate the mice spleen histology and immunotoxicity using skin acid secretion (SAS) of the sea slug _Berthellina citrina_ after oral administration. The spleen showed atrophy in the white pulp, decrease in the splenocytes density, megakaryocytes cytoplasmic degeneration as ... Read more

Comparative histopathological and histochemical impacts induced by the posterior salivary gland and ink sac extracts of Octopus vulgaris in mice
_Octopus vulgaris_ is of great importance for humans as a food resource and in fishery. The present study gave the first new insight about the comparative histopathological and histochemical impacts of oral administration of a single dose (25 mg/kg) of the posterior salivary gland (PSG) and ink sac (IS) extracts of O. vulgaris in mice. Histopathologically, the changes in the ... Read more

The present study dealt with the description of the reproductive and gametogenic cycles and the embryonic development of the freshwater mussel Nitia teretiuscula from the River Nile. Macro and micro-anatomy showed that the present species is dioceous and gonadosomatic indices showed that the species is semiannual and had two gonadal growth periods, a short period of gonadal growth from January ... Read more

Color Polymorphism in the Sea Slug Berthellina citrina (Rüppell and Leuckart, 1828) (Heterobranchia: Notaspidea: Pleurobranchidae) from the Red Sea
_Berthellina citrina _(Rüppell and Leuckart, 1828) is a common Pleurobranchid gastropod in the intertidal area of the Red Sea. It has distinct color pattern variation from pale yellow, orange to red. The present study aimed to evaluate whether the variation of these color patterns are due to polymorphism, or may be speciation. Anatomically, the three color patterns showed variations in ... Read more

Toxicological and Biological Activities of the Acid Secretion of Berthellina citrina (Heterobranchia, Pleurobranchidae) from the Red Sea
_Berthellina citrina _is a pleurobranchid opisthobranch characterized by its skin acid-secretion that contains sulphate and chloride ions with traces of organic matter. To identify defensive potential and bioactivity, we tested this secretion for the first time against _Artemia salina_, different strains of microorganisms, human RBCs and human cancer cell lines. It showed lethality to _A. salina _with LC50 values 83.86 ... Read more

New cytotoxic halogenated sesquiterpenes from the Egyptian sea hare, Aplysia oculifera
Two new sesquiterpenes, oculiferane (1) and epi-obtusane (2) have been isolated and identified from an acetone extract of the digestive gland of the sea hare, _Aplysia oculifera_. The structures were elucidated by spectroscopic analysis including HREIMS, 1H, 13C, DEPT, 1H–1H COSY, HMQC, and HMBC NMR; the relative configuration was confirmed by X-ray analysis. Compounds 1 and 2 exhibited cytotoxic activity ... Read more