Background The emergence of microbial resistance to conventional antibiotics and the environmental impact of chemical pesticides necessitates the search for alternative and sustainable solutions. This study explores the utilization of the dried biomass of the red algae Hypnea pannosa to synthesize silver nanoparticles (AgNPs) using a green and eco-friendly method. Results The synthesized AgNPs displayed sizes ranging from 15 to 60 nm with polydispersed shapes and a face-centered cubic crystalline structure, confirmed through characterization techniques including transmission electron microscopy (TEM), dynamic light scattering (DLS), and X-ray diffraction (XRD). Stability assessments via zeta potential measurements and docking studies of oleic acid and 9,12-octadecadienoic acid against Gyrase B and GST proteins were also conducted. The nanoparticles demonstrated potent antibacterial and antibiofilm activities, particularly against Staphylococcus epidermidis. Both the algal extract and the AgNPs exhibited significant larvicidal and adulticidal effects against Culex pipiens, with the nanoparticles showing superior efficacy, indicated by lower LC50 and LC90 values. The highest larvicidal effectiveness achieved was 93.33% for algal extract at 600 mg/L and 100% for AgNPs at 100 mg/L. Conclusions This study provides a sustainable method for producing AgNPs with diverse applications in medical and mosquito control fields, highlighting their potential as effective and safe alternatives to conventional antibacterial and insecticidal agents.

Zooplankton biomasses are essential nutritional sources for early-stage aquatic organisms due to their high-value nutrient profiles. Recent studies highlight the potential of zooplankton mixtures and Artemia franciscana (Leach, 1819) biomasses as protein-rich alternatives for fish diets. The current study analyzed these biomasses for chemical composition, vitamin content, and antioxidant properties. For the first time, a zooplankton mixture was evaluated for its antimicrobial, anti-biofilm, and anticancer activities against various pathogenic microorganisms and cancer cell lines. Antimicrobial assays demonstrated that both the zooplankton mixture and A. franciscana biomass exhibited inhibitory effects against Staphylococcus aureus ATCC 6538, Pseudomonas aeruginosa ATCC 27853, and Alternaria solani RCMB 009 003, as observed through agar well diffusion. Anti-biofilm testing showed that the biomass of the zooplankton mixture effectively inhibited biofilm formation by P. aeruginosa ATCC 27853 and S. aureus ATCC 6538. Additionally, anticancer activity was assessed against three cancer cell lines: breast (MCF-7), liver (HepG-2), and colon (HCT-116). The zooplankton mixture and A. franciscana biomass displayed cytotoxicity across all cell lines, with IC50 values for HepG-2 at 23.47 mu g mL- 1 and 14.48 mu g mL-1, respectively; for HCT-116 at 19.46 mu g mL- 1 and 13.05 mu g mL-1, respectively; and for MCF-7 at 26.51 mu g mL- 1 and 16.81 mu g mL-1, respectively. These findings suggest that both biomasses are promising candidates in medical applications, with potential antimicrobial and anticancer effects.

The current study was conducted to determine the precise mechanisms of Sirtuin-1 (Sirt-1), TGF- β (Transforming Growth Factor-β), and long non-coding RNA Metastasis Associated Lung Adenocarcinoma Transcript 1 (LncRNA MALAT-1) in signaling pathways in doxorubicin (DOX)-induced nephrotoxicity. The potential therapeutic effect of Resveratrol and Pirfenidone in DOX toxicity was also assessed. Thirty-six male adult rats were evenly distributed into four groups: Group 1: control rats. Group 2: DOX exposed rats' group, each animal received 7.5 mg/kg DOX as a single intravenous dose, Group 3: DOX exposed group subjected to oral resveratrol (20 mg/kg/daily for two weeks), Group 4: DOX exposed group subjected to oral Pirfenidone (200 mg/kg once daily for 10 days). At the planned time, animals were sacrificed. Renal tissue was collected to assess matrix metalloproteinase-9 (MMP9), inflammatory and apoptotic markers: tumor necrosis factor-alpha (TNF- β, caspase-3, cyclo-oxygenase-2 (COX-2), and oxidative stress markers: nitric oxide (NO), Glutathione (GSH), malondialdehyde (MDA), and superoxide dismutase (SOD). Sirtuin-1 (Sirt-1), TGF-β, and LncRNA MALAT-1 were quantitatively assessed by real-time RT-PCR in the whole blood. Results showed that the DOX group exhibited a significant increase in oxidative stress markers, and inflammatory, and apoptotic markers in the renal tissue. Histologically, the renal tubule lining cells exhibited vacuolar alterations in the cytoplasm, glomerular atrophy, and vascular congestion. Furthermore, renal degeneration was evident, as confirmed by the heightened immuno-expression of MMP9. Exposure to DOX resulted in a significant decrease in Sirtuin-1 (Sirt-1) with a significant increase in the TGFβ, and LncRNA MALAT-1 gene expression. However, pre-treatment with either resveratrol/or Pirefenidone ameliorated the histological renal alterations, regulated the pathways of Sirt-1, TGFβ, and LncRNA MALAT-1, and decreased all oxidative stress, inflammatory and apoptotic markers. In conclusion, DOX exposure leads to renal toxicity by inducing renal degeneration, oxidative stress, and apoptosis. Administration of either resveratrol or Pirfenidone counteracted these changes and protected the kidney against DOX-induced renal damage.

The anticancer, antimicrobial, and insecticidal activities of sarcotrocheliol (1) and cholesterol (2) obtained from the soft coral Sarcophyton trocheliophorum (S. trocheliophorum) were intensively studied. According to this study, both compounds 1 and 2 showed potential cytotoxicity towards the human colorectal carcinomaHCT-116 (IC50 10.4, 11.8 mu g/mL) and human liver carcinoma HepG2 cell lines (IC50 8.8, 12.0 mu g/mL), respectively. Compounds 1 and 2 were evaluated as potential inhibitors of caspase-3, a member of the cysteine protease family, which is considered a key enzyme in inducing cell apoptosis. Results showed that compounds 1 and 2 have induced apoptosis via up-regulation of caspase-3. Sarcotrocheliol (1) displayed antimicrobial activity against P. aeruginosa (15 mm), B. subtilis (15 mm), M. luteus (14 mm) and C. albicans (15 mm), with a MIC of 1.5 mu g/mL against the reported test microorganisms. On the other hand, cholesterol (2) showed less activity towards P. aeruginosa (10 mm), B. subtilis (14 mm), S. aureus (12 mm) and C. albicans (10 mm) with MICs of 3.0, 1.5, 1.5 and 3.0 mu g/mL against the tested microorganisms, respectively. Larvicidal activity revealed that compounds 1 and 2 induced remarkable toxicity against the third instar larvae of the mosquito, Culex pipiens even at concentration of 2 ppm. Adulticidal activity data showed that tested compounds are distinctly potent toxicants against the housefly, Musca domestica adult females. Overall, compound 2induced much more insecticidal activity than 1, and M. domestica adult females were more sensitive to tested compounds than C. pipiens larvae. Computationally, Density Functional Theory (DFT) analyses revealed that compound 2 had a higher dipole moment and lower band gap energy when compared to compound 1. So, compounds 2 is chemically more reactive and less stable than compound 1. According to the molecular docking study against PDB IDs: 3KJF, 5UHF and 1ACJ, compounds 1 and 2 demonstrated their activity mode as anticancer, antimicrobial, and insecticidal agents. The compounds exerted many interactions and showed high binding to the proteins, recognizing their potential as drug candidates with broad bioactivities.

Fractionation of the stem bark of Enantia chlorantha Oliv yields three alkaloids, palmatine (1), jatrorrhizine (2), columbamine (3), and β-Sitosterol (4). In this investigation, density functional theory (DFT) calculations were carried out to evaluate the electronic structure and properties of 1–4 by DFT-B3LYP/6-31G level of theory using Gaussian 09 software. The highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), HOMO-LUMO energy difference (band gap), hardness (η), softness (S), dipole moment (μ), electronegativity (χ), hydrophobicity (logP), topological surface area (TPSA), and energy gap (Eg) were calculated. The in vitro cytotoxicity of the compounds was investigated against MCF-7 and HCT116 cancer cell lines using Wi-38 cells as a control. The compounds inhibited the proliferation of the MCF-7 and HCT116 cell lines and induced apoptosis via upregulation of caspase-3, Bax, PARP cleavage, and downregulation of Bcl-2. DFT analyses revealed that compounds 1 and 3 have smaller energy gaps, 0.072 and 0.071eV, respectively, with the highest dipole moments; hence, these compounds are more chemically reactive and exhibit better modulation of caspase-3 enzyme and inhibitory activities of the MCF-3 and HCT116 cell lines. The antimicrobial and antiparasitic evaluation of 1–4 showed moderate efficacy against the bacterial strains and moderate antiparasitic activity against Cichlidogyrus tilapia.

This investigation examined the vulnerability of three branching coral species (Acropora humilis, Pocillopora damicornis, and Stylophora pistillata) to environmental changes within the marine reserves of Taba, Nuweiba, and Dahab in the Gulf of Aqaba. Coral growth rates were assessed as a key indicator of coral reef vitality, reacting to shifting physicochemical parameters. A. humilis manifested the highest growth rate, followed by S. pistillata and P. damicornis. Site-specific data analysis found Dahab displayed the greatest coral proliferation, with Taba exhibiting the least. Accounting for seasonal changes, spring showed maximal coral growth. Statistical analysis revealed a positive correlation between salinity and coral growth rate, contrasted by a negative correlation with variables such as pH, PO4-P, and silicate (SiO4-Si). This work underscores the significant influence of environmental factors on coral growth rates, and by extension, the health of coral reef ecosystems. These findings are integral to coral reef management, suggesting mitigation of adverse environmental factors could enhance these ecosystems’ resilience against climatic shifts and human-induced stressors. By combining species, site, seasonal, and physicochemical variations, this research underlines the importance of localized conservation strategies.

Stress-induced epidemic parasites and bacterial diseases are becoming a typical occurrence in fish aquaculture across the globe, those consider deadly infectious pathogens. To prevent losses on fish farms, it is crucial to obtain information on the infection severity and the characteristics of those diseases which have been peaked for fish farms and lead to mass mortality. This study investigates the effect of dual parasitic and bacterial infection on farmed tilapia, which leads to losses in farmed fish; focuses on the harmful effect of polluted water on speared infections in farming. During the production season, water and fish specimens were taken from private fish farms in El-Sharkia and Kafr El-Sheikh, Egypt, particularly during significant mortality times. The infected and uninfected fish samples were examined to determine bacteriological, parasitological, haemato-biochemical indices, immune responses, and pathologic changes besides water analysis in fish farming in the study area. It was discovered that fish were significantly infected with Centrocestus formosanus encysted metacercariae and/or Cichlidogyrus tilapiae, Heterophyes spp. Also, three species of gram-negative: Aeromonas hydrophila, A. sobria, Pseudomonas aeruginosa, and two Gram-positive cocci: Streptococcus agalactiae and Enterococcus faecalis. Identification of bacterial isolates was confirmed by using 16S rRNA gene sequencing. Results demonstrated substantial (P < 0.05) output losses in both farms. Results displayed negative effects of dual infection on the lost weight, whole-body biochemical, haemato-biochemical indices, digestive enzyme, immune responses, gene expression, and abnormal features histopathology in different organs of infected Nile tilapia. At the same time, most of the water Indices strayed considerably from standards. Thus, the obtained data indicated the detrimental impacts of dual infection and water quality deterioration on the health condition of Nile tilapia and might help us acquire a deeper understanding of yield loss as potentially severe economic repercussions for fish farms.

Elements accumulation in crayfish is proportional to the increase in bioavailability (direct contact) with the surrounding water, sediment, and feeding. Five heavy metals (Cu, Cr, Mn, Ni, and Ag) and lithium (Li) were analyzed in the sediment, water, and crayfish tissues. Elements (heavy metals and lithium) concentrations in sediment, water, and crayfish tissues showed significant differences between the two sampling stations (El-Qanatir and El-Rahawi drain). However, the levels of elements in crayfish tissues were arranged in declining order as hepatopancreas > gills > exoskeleton > muscles for Cu and Cr; hepatopancreas > exoskeleton > gills > muscles for Ni and Ag; and exoskeleton > gills > hepatopancreas > muscles for Li and Mn. The human health hazard evaluation of heavy metals and lithium exposure via edible tissue consumption was assessed for both children and adult consumers. The target hazard quotient THQ values of crayfish edible tissues (less than 1) will not impose any health implications for consumers who ingest edible tissues in sufficient quantities. Furthermore, the hazard index (HI) values reported for children and adult consumers were lower than one, indicating non-carcinogenic and carcinogenic hazards, suggesting that crayfish edible tissues are safe for human ingestion. This evidence also found that Procambarus clarkii could be a good bio-indicator organism for monitoring potentially metals in aquatic systems.

The Egyptian coast of Gulf of Aqaba, north of the Red Sea, suffers from severe destruction and deterioration in habitat and biodiversity due to anthropogenic activities and flooding. The present work aims to evaluate the impacts of different human activities and flooding on the biodiversity of macrobenthic invertebrates along the Egyptian coast of the Gulf of Aqaba. From January 2019 to December 2019, many field trips (12 trips) were conducted to survey macrobenthic invertebrate communities and monitor water quality at nine sites within three sectors along the study area. Each site was divided into four ecological zones and one of five categories, according to the main activities at each site. Furthermore, satellite data were used to monitor the progress of land use and turbidity in the study area. Therefore, the current study assesses the relationship between these factors and water quality and macrobenthic invertebrate distributions, similarity, diversity, dominance and abundance. The results revealed that 53 macrobenthic invertebrate species belonging to three phyla (Mollusca, Echinodermata and Annelida) and one subphylum (Crustacea) were recorded. The echinoderm Echinometra mathaei was the major eudominant species. The northern part of the Gulf was higher in abundance and diversity with low land use and lowest water turbidity, while the south part showed contrary findings. All statistical analysis confirmed that the dissolved oxygen concentration was considered the only limiting factor for the abundance and diversity of macrobenthic invertebrates. Also, the variation in activities at investigated sites affected the dominance state of species in each site. Moreover, GPS data confirmed that the tourism activity had the largest influence on marine ecosystems and biodiversity, followed by fishing and desalination practices. Otherwise, flooding has significant influence on marine habitats and creates a habitat in which other certain species can survive. In the absence of awareness, intervention and disregard for the effective coastal zone management concept, especially for the unique marine ecosystems such as the Gulf of Aqaba, the degradation of biodiversity will continue until extinction, and human life is rendered unsustainable.

Bioactive compounds extracted from marine organisms showed several biological activities. The present study is an extension of our earlier studies where we assessed the antiproliferative and pro-apoptotic activities of ethanol, methylene chloride, ethyl acetate, acetone, and chloroform crude extracts of sponges: Negombata magnifica (NmE) and Callyspongia siphonella (CsE) against cancer cells. Herein, we are extending our previous findings on both sponge species depending on an alternative methanol extraction method with more advanced molecular biochemical insights as additional proof for anticancer and antimicrobial activity of N. magnifica and C. siphonella. Therefore, sponge specimens were collected during winter 2020 from the Dahab region at the Gulf of Aqaba. Each sponge was macerated with methanol to obtain the crude extracts; NmE and CsE. GC–MS analysis presented a total of 117 chemical compounds; 37 bioactive, 11 represented previously as constituents for a natural organism, and 69 had no biological activities. NmE dose-dependently inhibited the growth of HepG2, MCF-7, and Caco-2 carcinoma cell lines compared to CsE, which unfortunately has no antiproliferative activity against the same cancer cells. NmE was found to induce G0/G1 cell cycle arrest in HepG2 cells with its inhibition for CDK6, Cyclins D1, and E1 in HepG2, MCF-7, and Caco-2 cells. NmE also activated ROS production in HepG2 cells and induced apoptosis in HepG2, MCF-7, and Caco-2 cells via an increase in pro-apoptotic protein Bax, caspase-3, and cleavage PARP, and a decrease in anti-apoptotic protein BCL2. Unlike its anticancer potential, CsE exhibited clear superior results as an antimicrobial agent with a wider range against six microbial strains, whereas NmE showed a positive antibacterial activity against only two strains.

In this study, the crude extract and its isolated compounds from the stem bark of Annickiachlorantha were tested for their larvicidal, developmental, and repellent activity against the mosquito vector, Culex pipiens, besides their toxicity to the non-target aquatic organism, the zebrafish (Danio rerio). The acute larvicidal activity of isolated compounds; namely, palmatine, jatrorrhizine, columbamine, β-sitosterol, and Annickiachlorantha methanolic extract (AC), was observed. Developmentally, the larval duration was significantly prolonged when palmatine and β-sitosterol were applied, whereas the pupal duration was significantly prolonged for almost all treatments except palmatine and jatrorrhizine, where it shortened from those in the control. Acetylcholinesterase (AChE) enzyme showed different activity patterns, where it significantly increased in columbamine and β-sitosterol, and decreased in (AC), palmatine, and jatrorrhizine treatments, whereas glutathione S-transferase (GST) enzyme was significantly increased when AC methanolic extract/isolated compounds were applied, compared to the control. The adult emergence percentages were significantly decreased in all treatments, whereas tested compounds revealed non-significant (p > 0.05) changes in the sex ratio percentages, with a slight female-to-male preference presented in the AC-treated group. Additionally, the tested materials revealed repellence action; interestingly, palmatine and jatrorrhizine recorded higher levels of protection, followed by AC, columbamine, and β-sitosterol for 7 consecutive hours compared to the negative and positive control groups. The non-target assay confirms that the tested materials have very low toxic activity compared to the reported toxicity against mosquito larvae. A docking simulation was employed to better understand the interaction of the isolated compounds with the enzymes, AChE and GST. Additionally, DFT calculations revealed that the reported larvicidal activity may be due to the differing electron distributions among tested compounds. Overall, this study highlights the potential of A. chlorantha extract and its isolated compounds as effective mosquitocidal agents with a very low toxic effect on non-target organisms.

Seaweed draws a lot of attention for its vital role in aquaculture as it contains beneficial biological compounds that undoubtedly might help in the development of this field. The current study sheds light on the potential efficiency of dietary supplements of Grateloupia acuminata and G. doryphore (Halymeniaceae) nanoparticles (GNS) at different levels with bionanocomposite cellulose acetate membranes (CA/bio-AgNps) on improved growth performance, digestive enzyme activity, immunity, antioxidative, resistance against infectious pathogens, and characterization of water quality treated with CA/bio-AgNps that is used in rearing Nile tilapia (Oreochromis niloticus). Four concentrations (0.1, 0.25, 0.5, and 1.0 ml/L) of GNS extract were tested as potential anti-bacterial and for the efficacy of being parasitic. Fish with an average weight (24.46 ± 0. 50 g) were apportioned into six experimental groups (T0, T1, T2, T3, T4, and T5) represented as 0.0%, 0.0%, 0.1%, 0.25%, 0.5%, and 1.0% GNS in diets with CA/bio-AgNps, respectively. Injection of fish with Aeromonas hydrophila was performed at the end of the trial. Chemical and bacteriological water indices significantly showed improvement after being treated with CA/bio-AgNps than the control group. Growth, carcass composition, digestive enzyme, and hematological and biochemical indices were significantly noticed positive (p< 0.05), especially T4 and T5, than the control group. In parallel, a significant improvement was noticed in serum lysozyme, total immunoglobulin, complement C3, antioxidative enzyme, and the relative expression of hepatic and inflammatory genes with an increased level of GNS (p< 0.05) are upregulated than the control group. Remarkably, GNS-supplemented diets and extracts provided positive efficacy against A. hydrophila with a decreased percentage of fish mortality, besides efficacy on antibacterial strains and Cichlidogyrus tilapiae, respectively. To sum up, the seaweed extract with CA/bio-AgNps resulted in better growth performance of fish, antipathogenic effect, and health status. Furthermore, CA/bio-AgNps were vital in improving water characteristics. They should be studied and applied more in the future.

Green synthesis of zinc oxide nanoparticles (ZnO-NPs) using the marine sponge, Spongia officinalis extract, and assessment of their antimicrobial and potential insecticidal activities were achieved in this study. Characterization of ZnO-NPs was done using UV–visible spectroscopy with surface plasmon resonance (SPR) peaked at wavelength 290 nm. Transmission electron microscopy (TEM) with spherical crystalline particle ranged from 3.22 to 11.5 nm. Fourier transform infrared (FTIR) spectral analysis showed the presence of different chemical function groups such as polysaccharides, hydrocarbons, phenols, amines, amides, and carboxylates that may help in reduction of zinc acetate and form ZnO-NPs. X-ray diffraction (XRD) indicated that ZnO-NPs were nanocrystalline. Additionally, dynamic light scattering (DLS) recorded 9 mV with negative polarity and conductivity of 274 µS/cm. Based on obtained results, Spongia officinalis ZnO-NPs (So-ZnO-NPs) exhibited antibacterial and antifungal activities. Tested So-ZnO-NPs severely induced larvicidal activity for tested mosquitoes with LC50 and LC90 of 31.823 and 80.09 ppm for Culex pipiens and 12.634 and 66.118 ppm for Anopheles pharoensis, respectively. Fecundity was significantly reduced to 50% at 80 ppm for C. pipiens and 83% at 40 ppm for An. pharoensis. Adult (male and female) longevity was significantly shortened with almost all applied concentrations. Adult mortality increased significantly in relation to applied concentrations to reach about 96.67% at 60 ppm of So-ZnO-NPs in C. pipiens and 100% at 50 ppm in An. pharoensis. Overall, this study highlights the possibility of using S. officinalis–mediated ZnO-NPs for mosquito control and drug development.

Cancer is a group of diseases associated with abnormal cell growth with potentiality to invade or spread to other parts of the body (Rady et al., 2018). It is considered as one of the major ailments threatening the humankind (Rady et al., 2018a). The current available cancer statistics are indicating that the number of new cancer patients has been reached over 10 million cases associated with over 6 million deaths representing roughly 12% of worldwide mortality (Rady et al., 2017, 2018a). Moreover, over 20 million new cancer cases are anticipated to be diagnosed in the year 2025 (Zugazagoitia et al., 2016; Rady et al., 2017) and potentially will be increased to 21.7 million with about 13 million cancer deaths by the year 2030 (Torre et al., 2015; Rady et ARTICLE INFO ABSTRACT Article History: Received: Sept. 21, 2020 Accepted: Oct. 24, 2020 Online: Nov. 1, 2020 _______________

Bioactive constituents of numerous marine organisms have been investigated recently for their preclinical and clinical anticancer activity. Three marine organisms: black-spotted sea cucumber: Pearsonothuria graeffei (Pg), lollyfish: Holothuria atra (Ha), and sea hare: Aplysia dactylomela (Ad), were collected during winter 2019 from Gulf of Aqaba, Red Sea, Egypt, and macerated with ethanol into three different extracts: PgE, HaE, and AdE, where each was in vitro assessed for its antiproliferative and proapoptotic properties on HepG2, HCT-116, and MCF-7 cancer cells. PgE dose-dependently inhibited the growth of HepG2, HCT-116, and MCF-7 cells within IC50 values 16.22, 13.34, and 18.09 μg/mL, respectively, while the IC50 values for the antiproliferative activity of HaE were 12.48, 10.45, and 10.36 μg/mL, respectively, and the IC50 values of AdE were 6.51, 5.33, and 6.87 μg/mL, respectively. All extracts were found to induce G0/G1 cell cycle arrest for HepG2 cells side by side with their inhibition of CDK2 on all three cell lines while all extracts were also showed to induce apoptosis in HepG2 cell line at pre-G 1 phase supplemented by their anticancer activity via proapoptotic protein Bax, caspase-3, and cleavage PARP increase, and antiapoptotic protein Bcl-2 downturn. Moreover, necrosis has been relatively noticed in HepG2 cell line as an additional anticancer activity for each extract. Our data introduced three ethanolic marine extracts as natural chemotherapeutic agents to be further developed for cancer control.

This work aimed to study the effects of recreational diving and snorkeling on the distribution, diversity, and abundance of surgeonfishes in six northern islands, different in their diving and snorkeling load, at the Hurghada area in the Egyptian Red Sea waters. SCUBA diving survey was conducted in summer 2019 using transect technique in the reef flat and reef slope in the study sites to compare total and single surgeonfish species census among sites and microhabitats. A total of six species of surgeonfish belonging to three genera were recorded during the current survey, including Zebrasoma xanthurum, Zebrasoma desjardinii, Acanthurus gahhm, Acanthurus sohal, Naso lituratus, and Naso unicornis. Z. desjardinii was the most abundant species, recording 41.2% relative abundance, followed by Acanthurus sohal (19%). In all sites, surgeonfish species diversity and average/total abundance in reef flat was always higher than that recorded in the reef slope. Meanwhile, the recreational effect results showed that, in reef flat habitats, surgeonfishes total/average abundance was inversely related to the numbers of divers and snorkelers across survey sites. In contrast, deeper habitat at the opened reef edge exhibited inverse distribution pattern, whereas, the obtained results showed that surgeonfish preferred the reef edge when the diving activities load increased.

The present investigation was carried out during summer 2016 to determine the possible bioactive components extracts with six solvents (Methanol, Methylene Chloride, EtOH, Ethyl Acetate, Acetone, and Chloroform) from soft coral, Sinularia maxima using GC-MS analysis. Sixty-four compounds were identified from the six extracts. The prevailing compounds in these extracts were Alloaromadendrene (8.8); Hexadecanoic acid, methyl ester (9.4); batilol (12.5); Dimethyl Sulfoxide (2.4); n-Hexadecanoic acid (9.6); Heneicosane (11.6); Octacosanol (12.5). The compounds produced by the studied soft corals possess antimicrobial activity against a number of Gram-positive and Gram-negative bacteria, fungi, and Cancer cell lines, in addition to other pharmaceutical activities.

Concentrations of heavy metals in the water, sediments andPatella caerulea (shells and soft tissues) were determined.

The present work aims to investigate the food items and the feeding habits of some Nile fish namely; Alestes baremoze, Labeo niloticus, Mormyrus kannume and Oreochromis niloticus that were collected from El-Qanater Al-Khairia during spring 2018 as well as to study their correlation with live food. The examination of the plankton samples revealed that there were 25 phytoplankton species belonging to 6 phyla of the plant kingdom. The common phytoplankton phyla were Bacillariophyta, Chlorophyta, Cyanophyta, and Dinophyceae. Twenty-five species and other immature stages representing the zooplankton community were categorized in ten groups of the animal kingdom. The dominant groups were Rotifera, Protozoa, Copepoda, Cladocera and Polychaeta. The benthic fauna collected from the study area comprised of 7 groups of the animal kingdom represented in 10 species and other immature stages. The recorded groups were Mollusca, Foraminifera, Annelida, Insecta and Decapoda. The present results showed that the feeding intensity in the studied fish were moderate, being 60% in A. baremoze; 53.85% in L. niloticus; 66.67% in M. kannume and 53.57% in O. niloticus. Analysis of the stomach contents revealed that A. baremoze is a plankton feeder and consumed a wide range of phyto- and zooplankton. L. niloticus is majorly herbivorous and consumed a great variety of plant food. M. kannume is mainly a carnivorous benthic feeder consuming a great range of animal food, while O. niloticus is mostly omnivorous consuming high varieties of plant and animal food. The forage ratio of stomach contents showed that A. baremoze and M. kannume are selective feeders. However, L. niloticus and O. niloticus depended on the food availability in nature and selectivity.