This study aimed to identify and differentiate the pearl oyster species along the Saudi coast of the Red Sea using morphology and molecular phylogeny. Pearl oysters were collected from six stations, covering different habitats along the Saudi Arabian coast on the Red Sea. Morphological examination included external and internal shell characteristics such as shape, color, and size. Molecular phylogenetic analysis was based on the mitochondrial cytochrome oxidase subunit I (COI) gene. The analysis of the morphological features revealed the presence of two distinct species in the family Pteriidae, Pinctada radiata and Pinctada margaritifera. P. radiata is a small-sized species with significant morphological variability, particularly among spat and juvenile stages. In contrast, P. margaritifera, a large-sized species, exhibited relatively uniform shell morphology with minor differences in structure, color, and size. Nevertheless, the findings of the phylogenetic analysis imply that samples identified morphologically as P. margaritifera may include at least two genetically distinct lineages. Hence, it is crucial to intensify efforts for further comprehensive studies using multiple genetic markers and corroborating nuclear data to understand the taxonomic diversity, evolutionary relationships, and biogeographic patterns of pearl oysters in the Red Sea and surrounding areas.
Innovative approaches are needed to potentially overcome resistance with skin pathogens. Utilizing marine biopolymers, such as carrageenan (CA) and chitosan (CH), for biosynthesis and conjugation with nanometals (e.g., Ag NPs) can enhance their bioactive and biological properties to help control microbial skin infections. Ag NPs with CA in the presence of ultrasonic processors, followed by capping with CH for preparing CH/CA-Ag NP nanocomposites, were biosynthesized and assessed as a potential antimicrobial agent for controlling antibiotic-resistant microbial skin infections. By detecting changes in their vibrational frequencies, structures, and shape, Fourier-transform infrared spectroscopy (FTIR), UV, XRD, TEM, and SEM were able to validate the formation of nanomaterials. They were then loaded onto cotton textiles, and all fabricated nanomaterials/textiles were assessed for inhibiting pathogens such as Candida albicans and Staphylococcus aureus. The synthesized Ag NPs and CH/CA-Ag NP nanocomposites had opposite charges and particle sizes with mean diameters of 14.2 and 264.3 nm, respectively. Cotton textiles loaded with Ag NPs, CH/CA, and CH/CA-Ag NPs effectively inhibited the growth of C. albicans and S. aureus, with CH/CA-Ag NPs being the most powerful. Scanning microscopy confirmed the powerful antimicrobial action of CH/CA-Ag NPs toward skin pathogens; microbial cells were completely lysed and deformed within eight exposures. The CH/CA-Ag NP nanocomposite can be recommended as an antimicrobial candidate toward microbial skin pathogens with minor potential toxicity.
This study aims to identify publication trends and the potential growth of published studies on the use of carbon sources used in the biofloc system. A bibliometric analysis was conducted for a sample of 82 scientific articles published during 2010–2022. The findings highlight the main researchers who publish their results in indexed journals and include the main institutions and their collaborative work networks. In the citation analysis, six clusters related to the carbon sources used in the biofloc system were recognized, identifying mainly molasses, rice bran, sugar, sugar beet by-product, but also biodegradable polymers. The studies are mainly on Nile tilapia, white shrimp and common carp. It can be concluded that the scientific productivity on the topic increased by 20.7 % between 2010 and 2022, the first works were specifically focused on identifying the effects of carbon on the productive performance of the species studied, but as research evolved, parameters of immunological responses and nutritional composition of aquatic organisms and flocs generated by different carbon sources were included. Egypt and India are the countries with the highest productivity on the subject. The study provides publication patterns and critical points as a starting point for future works.
The indiscriminate use of chlorpyrifos (CP) has led to significant environmental toxicity that adversely affects various water resources. The main metabolite of CP, 3,5,6-trichloro-2-pyridinol (TCP), is more toxic and persistent than CP. Most bacteria can degrade only CP but not TCP due to its antimicrobial activity. This study reports the efficiency of a new CP-degrading bacterium, Kosakonia sp. FYF33 (accession no. OK325589), which was isolated from CP-contaminated agricultural drainage water. Kosakonia sp. FYF33 was able to degrade 94.6 % of CP (700 mgl- 1) within 9 days of incubation, which further reached 96.1 % within 5 days of incubation when Plackett-Burman (PBD) and central composite designs (CCD) were applied. This study also revealed that the oph gene (accession no. OM502408), encoding an organophosphorus hydrolase (OPH), was responsible for CP degradation in Kosakonia sp. FYF33. Quantitative real-time PCR (qRT-PCR) analysis revealed a 5.27-fold expression of this gene under CP treatment, indicating enhanced enzymatic activity for pesticide breakdown. On the basis of GC-MS analysis, a probable pathway for CP breakdown has been proposed that follows the pathway from CP to TCP to 2-ethyl-6-methyl-3-hydroxypyridine and then enters the TCA cycle. These findings could impact the development of bioremediation strategies. This study is considered the first publication to employ PB and CCD to optimize the degradation of CP and to elucidate the degradation pathway by the genus Kosakonia.
A 90-day growth trial evaluated seabass performance and welfare when integrated with carpet-shell Ruditapes decussatus (CSC) and short-necked Paphia undulata (SNC) clams in saline groundwater-based culture. Seabass (n = 270) weighing 90.92 +/- 0.15 g/fish were stocked in nine 1000-L tanks (30 fish/tank), which were divided into three groups in triplicate: (SB) seabass, (SB-CSC) seabass with carpet shells, and (SB-SNC) seabass with short-necked clams. Two kgs of CSC and SNC (mean weights of 10.70 and 10.40 g/clam) were suspended in four floating trays (0.5 kg/tray) in the SB-CSC and SB-SNC water tanks, respectively. The daily feeding was 3 % of the fish weight, and the water exchange was 5 %. The results revealed that the SB-CSC and SB-SNC groups had healthier culture water (higher dissolved oxygen (DO2) and lower levels of NH3, NO2, and heavy metals) than the SB group. Both the SB-CSC and SB-SNC groups presented reduced heavy metal levels in fish muscles but improved growth, feed efficiency, and crude protein. Furthermore, the integrated groups presented significant improvements in serum growth hormones, antioxidant and immune parameters and declines in metabolic (ALT, AST and urea) and stress (i.e., cortisol and glucose) markers. Therefore, coculturing seabass with SNC appears most beneficial and is recommended for saline groundwater-based aquaculture systems.
