Differential Fatty Acids and Stress Biomarkers Responses in Native (Carcinus Aestuarii) and Invasive (Portunus Segnis) Crabs Exposed to Environmental Pollution

The present work aims to determine and compare the tolerance to different stress environmental conditions in two crabs’ species the native Carcinus aestuarii and the invasive Portunus segnis. In this study, C.aestuarii appeared more intolerant to environmental stressor as shown by the important changes occurred on the proximate, fatty acids and their essential compounds comparing to P.segnis. Our results revealed accumulation of metallic trace elements, macromolecular damages and antioxidant defense systems perturbations mostly in C.aesuarii gills and muscles than P.segnis, thus highlighting the importance of a multi-markers approach to assess the urban pollution in coastal ecosystems. According to this study, fatty acid profiles and oxidative stress biomarker examination of both crabs indicate that the different environmental stresses significantly influence the tolerance of C.aestuarii compared to the invasive P.segnis which may provide physiological advantages for the achievement of their invasion in novel ecosystems.

Extraction and Characterization of Chitin, Chitosan, and Protein Hydrolysate From the Invasive Pacific Blue Crab, Portunus Segnis (Forskål, 1775) Having Potential Biological Activities

The diversity of marine biomasses is a set of exploitable and renewable resources with application in several sectors. In this context, a co-culture based on three protease-producing bacterial isolates namely; Aeribacillus pallidus VP3, Lysinibacillus fusiformis C250R, and Anoxybacillus kamchatkensis M1V strains, was carried out in a medium based on the blue swimming crab Portunus segnis bio-waste. Proteases production was optimized using a central composite design (CCD). The highest level of proteases production obtained was 8,809 U/mL in a medium comprising 75 g/L of Portunus segnis by-product powder (Pspp). The biological value of Pspp and its obtained derivates were evidenced via accredited protocols. The recovered protein hydrolysate (PHyd) was found to be active towards radical scavenging power, and against angiotensin I-converting enzyme (ACE). The blue crab chitin (BC) extraction efficiency was achieved with a yield of 32%. Afterward, chitosan was prepared through chitin N-deacetylation with a yield of 52%, leading to an acetylation degree (AD) of 19% and solubility of 90%. In addition, chitosan is found to be active against the growth of all pathogenic bacteria tested.

Review of range extensions of tropical brachyuran crabs into temperate waters of southern Africa

We compiled known occurrence records of seven species of crabs identified in the literature and one documented in this report as having undergone range extensions in southern Africa. Of these eight species, six (Austruca occidentalis, Neosarmatium africanum, Ocypode ceratophthalmus, Portunus segnis, Tubuca urvillei, and Varuna litterata) have extended their ranges either across a major biogeographic boundary that separates the subtropical and warm temperate ecoregions of this coast, or into estuaries that historically lack mangrove forests. For the seventh and eighth species, Charybdis smithii and Scylla serrata, we were unable to find any distributional data that supported poleward range extension. In addition, we contribute the first record of the blue swimming crab, P. segnis, from the temperate south coast of South Africa. This early detection is likely to be part of an ongoing regional trend of tropical-adapted brachyuran crab species extending their ranges into temperate ecoregions.

Evaluating the Performances of Interval Starting Accessibility Drying (ISAD) through Protein and Total Polyphenol Contents of Blue Crabmeat (Portunus segnis)

Blue crab (Portunus segnis) proliferation on Tunisian coasts started in 2014/2015. It has heavily impacted the balance of other species, local biodiversity, and fishing activity. Limiting these drawbacks may be achieved through ways promoting crabmeat. For this purpose, two different drying modes were tested: Conventional convective drying (CCD) and interval starting accessibility drying (ISAD) under 45 °C and relative humidity of 40%. Several air velocities were assayed under CCD: 1.5, 2.5, 3.5, and 5 m.s−1. Two different ISAD tests were run with different time-related conditions: drying period of 15 s and tempering period of 15 or 60 s. Drying modes and operating conditions performances were compared through proteins and total polyphenol contents (TPCs) evolution during the treatment. Important polyphenol and protein losses were observed between raw and processed crabmeat. Airflow velocities have a significant effect on crabmeat quality preservation. ISAD method under 15 s/60 s allowed the best preservation of these quality parameters. TPC and proteins losses and kinetics during drying under CCD or ISAD were modelled and correlations were established between the quality parameters, the residual water content at all drying times, and the evaporation rate.

Trends in valorization of the invasive crab Portunus segnis for cleaner production of chitin, chitosan, and protein hydrolysate

The diversity of marine biomasses is a set of exploitable and renewable resources with application in several sectors. In this context, a co-culture based on three protease-producing bacterial isolates namely; Aeribacillus pallidus VP3, Lysinibacillus fusiformis C250R , and Anoxybacillus kamchatkensis M1V strains, was carried out in a medium based on the invasive blue crab Portunus segnis bio-waste. Optimization of proteases production was performed using a central composite design (CCD). The highest level of proteases production obtained was 8,809 U/mL in a medium comprising 75 g/L of Portunus segnis by-product powder (Pspp ). The recovered protein hydrolysate (P Hyd ) was found to be active towards radical scavenging power, and against angiotensin I-converting enzyme (ACE). The extraction efficiency of the blue crab chitin (BC) was achieved with a yield of 32%. Afterward, chitosan was prepared through chitin N -deacetylation with a yield of 52%, leading to an acetylation degree (AD) of 19% and solubility of 90%. The spectrum of chitin and chitosan were depicted by Fourier-transform infrared spectroscopy (FTIR). The biological value of Pspp and its obtained derivates were evidenced via accredited protocols. These data constitute a roadmap towards a circular and sustainable bio-economic strategy for a clean transformation of a recalcitrant waste to bio-based products.

Gonadal cycle of the blue crab Portunus segnis (Forskål, 1775) (Decapoda, Portunoidea) in the Mediterranean Sea off Alexandria, Egypt

Adults of Portunus segnis were captured from Ras el Tin beach on the Mediterranean Sea at Alexandria, Egypt, from January to December 2017. Male crabs are present in higher density in the sea during fall and winter, while female crabs are more common during spring and summer. Sex ratios were calculated as follows: number of males or females/total number of crabs. The calculated sex ratios were subjected to a Chi-square test according to the equation: , where O represents the observed frequency and E the expected frequency. One-way analysis of variance shows differences in the carapace size (length and width) and the weight of males and females during the four seasons. The hepatosomatic index of male crabs ranges from 9.1-9.25 in winter months, 8.7-7.9 in fall, being lower, 3.12-2.25, in spring and 5.96-4.13 in summer. The hepatosomatic index of female crabs is 8.9-3.9 in spring, 9.2-7.9 in summer, shifts lower to 5.1-3.2 in fall and to 4.2-1.5 in winter. The gonadosomatic index of female crabs is 0.12-8.2 in spring, 0.20-13.9 in summer and decreases to 0.66-7.8 in fall and 0.18-4.7 in winter. Ovaries and testes were isolated, fixed, and prepared for histological examination. The testicular lobes are surrounded by simple epithelium with haemolymph filling the interspaces. Seminiferous ducts are inserted in the testicular lobes. Spermatogenesis and spermiogenesis are described. The vas deferens is usually filled with spermatophores. Spermatophore formation begins in the testis near the vas deferens. Near the base of the penes there is glandular tissue. This study proposes the classification of the ovarian maturation into five stages: Stage I, Immature ovary with primary and secondary oogonia; Stage II, early maturing ovary with germ cells in different maturation phases; Stage III, mature ovary with vitellogenic oocytes and germ cells; Stage IV, maturing ovary with oocytes I, II and fully mature oocytes; and Stage V, ovary in regeneration. The wall of the spermatheca consists of a stratified squamous epithelium.

Promising Chemoprevention of Colonic Aberrant Crypt Foci by Portunus segnis Muscle and Shell Extracts in Azoxymethane-Induced Colorectal Cancer in Rats

Background and Purpose: This study subjected a rat model to the extracts of muscle and shell tissues from Portunus segnis to assess their therapeutic effects on the HT-29 colon cancer cells as well as on colonic Aberrant Crypt Foci (ACF) induced by Azoxymethane (AOM). Methods: The cell line was exposed to the extracts to compare the cytotoxicity of hexane, butanol, ethyl acetate, and water extract of muscle and ethanolic extract of the shell. Male rats (n=40) were assigned into control, positive, negative, and treatment groups. The animals were injected with AOM, except the control group, and then exposed to 250 and 500mg/kg of the crude extracts. Immunohistochemical localization of Bax and Bcl-2, as well as ACF and antioxidant enzymes, were evaluated in the rat colon. Results: The butanolic muscle extract and ethanolic shell one demonstrated an IC50 of 9.02±0.19μg/ml and 20.23±0.27μg/ml towards the cell line, respectively. Dietary exposure inhibited the ACF formation and crypt multiplicity in the colon compared to the cancer control group. The activity of SOD and CAT increased, while that of MDA decreased. The expression of Bax and Bcl-2 increased and decreased, respectively. Conclusion: Taken together, the results show that both extractions were suggested to be suppressive to AOMinduced colon cancer.