Mitogenomic Features and Evolution of the Nile River Dominant Tilapiine Species (Perciformes: Cichlidae).

To better understand the diversity and evolution of cichlids, we sequenced, assembled, and annotated the complete mitochondrial genomes of three Nile tilapiine species (Coptodon zillii, Oreochromis niloticus, and Sarotherodon galilaeus) dominating the Nile River waters. Our results showed that the general mitogenomic features were conserved among the Nile tilapiine species. The genome length ranged from 16,436 to 16,631 bp and a total of 37 genes were identified (two ribosomal RNA genes (rRNAs), 22 transfer RNA genes (tRNAs), 13 protein-coding genes (PCGs), and 1 control region). The ND6 was the only CDS that presented a negative AT skew and a positive GC skew. The most extended repeat sequences were in the D-loop followed by the pseudogenes (trnSGCU). The ND5 showed relatively high substitution rates whereas ATP8 had the lowest substitution rate. The codon usage bias displayed a greater quantity of NNA and NNC at the third position and anti-bias against NNG. The phylogenetic relationship based on the complete mitogenomes and CDS was able to differentiate the three species as previously reported. This study provides new insight into the evolutionary connections between various subfamilies within cichlids while providing new molecular data that can be applied to discriminate between Nile tilapiine species and their populations.

Detection of polymorphism within leptin gene in Egyptian river buffalo and predict its effects on different molecular levels.

BACKGROUND: Leptin (LEP) regulates the glucose homeostasis directly and centrally by the regulation of the insulin levels or indirectly by alternation of the levels of the other glucose metabolism regulator hormones. The present investigation studied the polymorphism in LEP gene which is related to fertility in 81 female Egyptian river buffalo. RESULTS: The PCR-RFLP pattern of the gene using the restriction enzyme Eco91I showed that all the animals had monomorphic pattern in the studied gene which consists of CC. A 511-bp fragment from LEP gene was amplified and sequenced. The homology between the amplified LEP gene fragment in buffalo and cattle, sheep, goat, human, and mouse on the nucleotides sequence level was 99, 97, 97, 87, and 79%, respectively, and on the translated amino acids sequence level was 100, 98, 98, 85, and 82%, respectively. Several SNPs were detected; among them, the T27C SNP disrupted an intronic splicing silencer. The A114G, A310G, G263A, and G379A SNPs disrupt exonic splicing enhancers, and the last two SNPs create new exonic splicing enhancers. The A114G, C163A, A211G, G288A, A310G, A322G, G330C, C348T, T360C, and G379A SNPs cause S71G, T87 N, N103S, E129K, E136G, Y140C, E143Q, R149W, S153P, and R159Q amino acids mutations. N103S, E129K, E136G, Y140C, E143Q, and S153P were classified as deleterious mutations. Y140, E143, N103, and R149 were the most conserved among the mutated amino acids. S71G only increased the stability of the leptin protein while the remaining mutations decreased it. CONCLUSION: Four SNPs were revealed among the tested animals. Twenty-one SNPs were found between the sequenced amplicon and the buffalo records in the Genbank. Some SNPs were predicted to have several effects on different biological processes like mRNA splicing, protein stability, and the gene functions.

Sustainable and resilient management scenarios for groundwater resources of the Red Sea coastal aquifers.

Gravity Recovery and Climate Experiment (GRACE) data, along with readily available remote sensing datasets and the outputs of land-surface and climate models, are used to monitor spatiotemporal variabilities in the groundwater resources of the Red Sea Coastal Aquifer (RSCA) system in Saudi Arabia; to investigate their responses to climate projections; and to provide sustainable and resilient management scenarios for these resources. Our results indicate that, during the investigated period (April 2002-June 2017), the RSCA received an average annual recharge of 3.16 ±â€¯0.52 km3. Recharge events (~16% of rainfall) are related to the observed increase in rainfall rates. Analysis of climate models' outputs over the RSCA indicates an increase in the median annual rainfall (17-31%) and recharge rates (2.7-4.9%) by the end of the 21st century. To ensure sustainable management and utilization of RSCA's water resources, groundwater extraction should be located in the southern and central parts of the aquifer, and groundwater extraction rates should be kept lower than 2.0 km3/yr. Findings highlight the importance of GRACE data as a unique, cost-effective, and decisive tool in monitoring the health of coastal and inland aquifer systems across the globe.

Effect of phytase enzyme on growth performance, serum biochemical alteration, immune response and gene expression in Nile tilapia.

The present study aimed to investigate the effect of low phosphorus diet with or without different levels of phytase enzyme supplementation on growth performance, body composition, nutrient retention efficiency, gene expression, and health status of A. hydrophila challenged fish. A total of 240 monosex males of Nile tilapia (Oreochromis niloticus) with an average body weight of 23.19 ±â€¯0.15 g/fish were used. Fish were randomly chosen and divided into 4 equal groups (60 fish per group), with 3 subgroups containing 20 fish as a replicate. Group 1, was fed on a diet containing 100% P, group 2, was fed on a diet containing 50% P, group 3 and 4, were fed on low P with 500 or 1000 units of phytase/Kg respectively. It was observed that the 50% phosphorus diet significantly reduced body weight, feed intake, feed conversion ratio (FCR), and protein efficiency ratio (PER) compared to Nile tilapia fish fed on the diet containing 100% phosphorus. In contrast, fish fed on the diet containing 50% phosphorus supplemented by 500 or 1000 phytase units/kg significantly (P ≤ 0.05) increased final body weight (FBW), total body gain (TBG), average daily gain (ADG), and weight gain compared to Nile tilapia fed on the same diet or fed on the diet containing normal phosphorus without phytase supplementation. Different phosphorus and phytase supplementation levels had no significant effect on serum total protein, albumin, and globulin concentrations, meanwhile, phytase supplementation increased serum calcium and phosphorus levels. Nile tilapia fed on phytase supplementation had an increase in body protein, lipid content, and nutrient utilization efficiency compared to Nile tilapia fed on the diet containing 100% phosphorus. Nile tilapia fed on low dietary phosphorus showed an increase in mortality after infection and a decrease in phagocytosis and neutrophil compared to fish fed on normal phosphorus. Phytase supplementation, made immune response parameters return to its normal values and the pathological lesions of liver, spleen, stomach, and intestine were reduced. Moreover, normal phosphorus significantly up-regulated lipoprotein lipase (LPL) mRNA expression and down-regulated fatty acid synthase (FAS) mRNA in Nile tilapia's liver while low phosphorus with or without phytase supplementation reduced LPL expression and relatively up-regulated FAS.