Journal of King Abdulaziz University: Marine Sciences

Potential impacts of Hematodinium perezi on the male reproductive system of Portunus segnis from the Great Bitter Lake, Egypt

2023-08-27T07:21:50+00:00

From October 2020 to September 2021, researchers examined various facets of the reproductive biology of male Portunus segnis crabs caught in the fishing port of the Great Bitter Lakes on Egypt's Suez Canal coast. The male reproductive system of Portunus segnis consists of two testes, a commissure, two vas deferentia, and two ejaculatory ducts internally. It is bilaterally symmetrical and creamy to whitish in appearance. The three components of Vas deferentia were the Anterior (AVD), Median (MVD), and Posterior (PVD). There are three stages of male gonad development: immature, maturing, and mature. For light microscopic examinations, tissues from the testis, anterior vas deferens (AVD), median vas deferens (MVD), posterior vas deferens (PVD), and ejaculatory duct were fixed in Bouin's solution. The blue swimming crab Portunus segnis is an important host of parasitic dinoflagellates from the genus Hematodinium. The blue swimming crab Portunus segnis's commercial supplies have been harmed by outbreaks of these parasites. Hematodinium perezi, a dinoflagellate, had no discernible impact on the gonad growth and development of its host Portunus segnis. For uninfected and infected males, the size at first sexual maturity was estimated to be 66.3 and 67.3 mm carapace width, respectively.

Red Sea marine algae extracts-based silver nanoparticles as antibacterial-anticancer agents

2023-09-09T06:21:48+00:00

Algae extracts are usually embracing a variety of metabolites that are generally nontoxic and biodegradable. Eight seaweeds belong to red algae (Bostrychia tenella, Laurencia majuscula, L. obtusa, and L. Papillosa), green algae (Caulerpa racemose and Halimeda tuna), and brown algae (Cystoseira trinodis and Sargassum aquifolium) were collected from the Red Sea waters off Jeddah city, Saudi Arabia, and extracted with methanol. Silver nanoparticles were individually synthesized through eco-friendly benign chemistry approach using methanolic extracts of the collected algae. The identity and characterization of the prepared nanoparticles were confirmed by scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDS). the antimicrobial activity of the total extract and isolated compounds was estimated against a set of Gram-negative and Gram-positive. S. aquifolium and L. obtusa extracts - based AgNPs showed the most remarkable antibacterial effects against all tested Gram-negative bacteria with diameter of inhibition ranging from 17±3.0 to 12±0.9 mm. Also, S. aquifolium and L. obtusa extracts - based AgNPs exhibited cytotoxicity against HepG2, PC-3, and HeLa cancer cells with IC₅₀ values (µg/mL) ranging between 20.6 ± 1.5and 52.9 ± 7.10. The obtained results indicated that Sargassum and Laurencia–based AgNPs showed remarkable cytotoxic and antibacterial activities.

The effects of dietary administration of two sources of β-glucan on growth and physiological activity of common carp

2023-12-26T14:47:14+00:00

A growth experiment has been established to estimate the influence of two diverse sources of β-glucan, fungal derived from baker's yeast Saccharomyces cerevisiae and vegetal derived from barley bran Hordeum vulgare as long-term effect on the growth performance, survival rate, and physiological status in fingerlings of common carp (Cyprinus carpio) after 60 days of feeding on artificial diets containing 3% fungal β-glucan (A group), 3% vegetal β-glucan (B group), as well as 0% β-glucan (C group) as a control in duplicate for each group. Some of the blood parameters such as Packed cell volume PCV, osmotic pressure OP, total protein content TP, glucose content GLU., enzymes of ALP, AST, and ALT were estimated. Results of growth performance including weight increase, growth rates, relative growth rates, and specific growth rates as well as survival rates showed no significant variances (P > 0.05) among the three groups, although there were rises in these values in groups of fungal (A) and vegetal (B) sources of β-glucan additives than the control group C. Contrariwise, most of the physiological parameters estimated in the fish blood showed a significant improvement in performance in group A and then B, where PCV, OP, TP, GLU, ALP, AST, and ALT values showed a significant decline (P < 0.05) for A group and for B group, from the control group C. The study confirmed that the addition of β-glucan, especially that derived from a fungal source to fish diets, led to a non-significant increase in growth and survival rates, while it guided to a significant improvement in the physiological activities of the parameters PCV, OP, TP, GLU, ALP, AST, and ALT in the fish blood. The study encourages the addition of the fungal source of β-glucan to the artificial diets of common carp as Immunostimulator for its health enhancement.

Activity of cell-free supernatant from Sponge associated bacteria against the growth and bacterial adhesion of microfouling Bacteria

2023-09-14T10:26:32+00:00

This study was carried out to evaluate the activity of cell free supernatant (CFS) from sponge associated bacteria against the growth and bacterial adhesion of biofilm bacteria. A sponge was collected from the Red Sea by Scuba diving and identified as Hyrtios erectus. After washing and cleaning to remove loosely attached bacteria, endophytic bacteria were isolated from the sponge by serial dilution method using Zobell Marine Agar (ZMA) as growth medium. Pure culture of the bacteria obtained were then identified by 16s rRNA gene sequencing method. The cell free supernatant (CFS) from two strains of bacteria isolated from the sponge were subjected to bacterial growth inhibition and bacterial adhesion inhibition assay using bacterial growth inhibition assay method and microtiter plate assay method respectively against four microfouling bacteria. The two organisms were identified as Idiomarina sp. MS-E2 and Staphylococcus edaphicus MS-E4. Both organisms show potential inhibition activity against the tested biofilm bacteria by inhibiting their growth and adhesion ability. This is an indication of the role of the sponge associated bacteria in producing compounds with potential activity against bacterial adhesion to surfaces.

Embryonic developmental study of Pink skunk clownfish, Amphiprion perideraion (Bleeker, 1855)

2023-10-01T11:59:04+00:00

The present study was conducted to document the embryonic developmental stages of clownfish, Amphiprion perideraion in captivity. The water quality parameters such as salinity (30 ppt), pH (8.2), temperature (28 ± 1°C), ammonia and nitrite (below the detectable levels) were standardized and maintained throughout the study period. The newly spawned eggs were adhesive, telolecithal, and white to yellowish-white-colored yolk. The eggs measured around 2.0-2.1 mm in length and 0.9-1.0 mm in width. The chorion was transparent and embryonic developmental stages could be observed directly through the shell. A large clear oil droplet and several smaller droplets were observed. After one hour, blastodisc appeared at the animal pole followed, and various cleavage stages were noted; two, four, eight, sixteen, thirty-two and sixty-four-cells stages, then, morula, blastula, and gastrula were observed. The organogenesis process started after fertilization and later head and notochord formation was evident. The optic vesicles first appeared after 32 hours of fertilization. The turnover stage was passed after 42:10 hours post fertilization (hpf), heart beating and blood circulation started 68:13 hours post fertilization. Lower jaw development started after one hundred twenty-three hours post-fertilization. The embryo reached the pre-hatching stage and hatching was attained after 177 hours of incubation