Molecular cloning, expression and characterization of a functional GSTmu class from the cattle tick Boophilus annulatus

A full-length cDNA of a glutathione S-transferase (GST) was cloned from a cDNA library of the local Egyptian cattle tick Boophilus annulatus. The 672 bp cloned fragment was sequenced and showed an open reading frame encoding a protein of 223 amino acids. Comparison of the deduced amino acid sequence with GSTs from other species revealed that the sequence is closely related to the mammalian mu-class GST. The cloned gene was expressed in E. coli under T7 promotor of pET-30b vector, and purified under native conditions. The purified enzyme appeared as a single band on 12% SDS-PAGE and has a molecular weight of 30.8 kDa including the histidine tag of the vector. The purified enzyme was assayed upon the chromogenic substrate 1-chloro-2,4-dinitrobenzene (CDNB) and the recombinant enzyme showed high level of activity even in the presence of the beta-galactosidase region on its 5' end and showed maximum activity at pH 7.5. The Km values for CDNB and GSH were 0.57 and 0.79 mM, respectively. The over expressed rBaGST showed high activity toward CDNB (121 units/mg protein) and less toward DCNB (29.3 units/mg protein). rBaGST exhibited peroxidatic activity on cumene hydroperoxide sharing this property with GSTs belonging to the GST alpha class. I50 values for cibacron blue and bromosulfophthalein were 0.22 and 8.45 microM, respectively, sharing this property with the mammalian GSTmu class. Immunoblotting revealed the presence of the GST molecule in B. annulatus protein extracts; whole tick, larvae, gut, salivary gland and ovary. Homologues to the GSTmu were also detected in other tick species as Hyalomma dromedarii and Rhipicephalus sp. while in Ornithodoros moubata, GSTmu homologue could not be detected.     

Wound Healing Metabolites from Peters’ Elephant-Nose Fish Oil: An In Vivo Investigation Supported by In Vitro and In Silico Studies

Gnathonemuspetersii (F. Mormyridae) commonly known as Peters’ elephant-nose fish is a freshwater elephant fish native to West and Central African rivers. The present research aimed at metabolic profiling of its derived crude oil via GC-MS analysis. In addition, wound healing aptitude in adult male New Zealand Dutch strain albino rabbits along with isolated bioactive compounds in comparison with a commercial product (Mebo^®). The molecular mechanism was studied through a number of in vitro investigations, i.e., radical scavenging and inhibition of COX enzymes, in addition to in silico molecular docking study. The results revealed a total of 35 identified (71.11%) compounds in the fish oil, belonging to fatty acids (59.57%), sterols (6.11%), and alkanes (5.43%). Phytochemical investigation of the crude oil afforded isolation of six compounds 1–6. Moreover, the crude oil showed significant in vitro hydrogen peroxide and superoxide radical scavenging activities. Furthermore, the crude oil along with one of its major components (compound 4) exhibited selective inhibitory activity towards COX-2 with IC₅₀ values of 15.27 and 2.41 µM, respectively. Topical application of the crude oil on excision wounds showed a significant (p < 0.05) increase in the wound healing rate in comparison to the untreated and Mebo^®-treated groups, where fish oil increased the TGF-β1 expression, down-regulated TNF-α, and IL-1β. Accordingly, Peters’ elephant-nose fish oil may be a potential alternative medication helping wound healing owing to its antioxidant and anti-inflammatory activities.     

Effects of feeding regimen of dietary Aspergillus oryzae on the growth performance,intestinal morphometry and blood profile of Nile tilapia (Oreochromis niloticus)

The current study was conducted to evaluate the feeding regimen of Aspergillus oryzae (ASP) on the growth, intestinal histomorphology and blood profile of Nile tilapia (Oreochromis niloticus). Four different ASP‐feeding regimens were evaluated, including feeding the basal diet continuously (control), feeding ASP (1 g/kg) continuously (ASPC), feeding ASP for 1 day and the next day without (ASPF1) or feeding ASP for 1 day and the two next days without (ASPF2). After 60 days, the final weight, weight gain, SGR, feed intake, protein efficiency, protein gain, body protein content, haematocrit, haemoglobin, and RBC and WBC values were increased significantly (p < 0.05) with lower glutamic‐pyruvate transaminase in ASPC group compared to the control without no difference (p > 0.05) with ASPF1‐feeding regimen. Interestingly, glutamyl oxaloacetic transaminase was significantly reduced in all feeding regimens compared to the control (p < 0.05). Protease, lipase and villi length were significantly (p < 0.05) improved in all feeding regimens compared to the control, while amylase activity increased only in ASPC group. Thus, the obtained results indicated that all ASP‐feeding regimens resulted in quite similar outcomes with respect to growth, digestive enzyme activity and intestinal histomorphology.     

Alleviating effects of β‐glucan in Oreochromis niloticus on growth performance,immune reactions,antioxidant, transcriptomics disorders and resistance to Aeromonas sobria caused by atrazine

Three hundred Oreochromis niloticus were divided into five groups; the control fish (CNT) were fed a basal diet, beta glucan (βG) group was fed 0.5 g/kg^?1 βG, atrazine (ATZ) group was exposed to 1/5 96‐hr LC₅₀ (1.39 mg/L) ATZ, the (βG/ATZ) group was fed βG while being exposed to ATZ, and the (βG then ATZ) group was supplemented with βG for fifteen days before exposed to ATZ. ATZ exposure caused a decline in growth that was ameliorated by βG. ATZ reduced the levels of total and different types of leucocytes. Additionally, ATZ exposure caused reductions in total proteins, globulins, α 1‐globulin, α 2‐globulin, ?‐globulin, immunoglobulin M, lysozymes, superoxide dismutase, nitric oxide and catalase but increases in hepatic transaminases and malondialdehyde without any variations in albumin and β‐globulin. Exposure to ATZ also resulted in a rise in the mRNA level of IL‐8. In contrast, expression of IgM, SOD and CAT were decreased in the tilapias exposed to ATZ. Exposure to ATZ increases the susceptibility response to Aeromonas sobria challenge, as indicated by an increase in cumulative mortality post‐challenge. Supplementation with βG fifteen days before (βG then ATZ group), counteracted the adverse effects of ATZ on the immune, biochemical and antioxidants values, though only slight alleviation was observed with simultaneous treatment (βG/ATZ group). Our results established that ATZ has adverse impacts on immune responses, antioxidant equilibrium and its related genes. While, supplementation with βG before exposure to ATZ may be valuable for counteracting the possible damage caused by ATZ water pollution than its simultaneous treatment with ATZ.     

Effect of short‐term fasting and re‐feeding on growth,digestive enzyme activities and antioxidant defence in yellowfin seabream,Acanthopagrus latus (Houttuyn, 1782)

An 80‐day feeding trial was conducted to evaluate the influence of different short‐term fasting and re‐feeding strategies on growth and physiological responses in yellowfin seabream, Acanthopagrus latus (2.4 ± 0.2 g) fingerlings. The fish were subjected to four different feeding regimes, and the control group fed four times daily to apparent satiation throughout the whole feeding period, while the other three groups were deprived for 2, 4 and 8 days followed by 8, 16 or 32 days of re‐feeding (F₂R₈, F₄R₁₆ and F₈R₃₂, respectively) in repeated cycles for 80 days. The fish in the control and F₂R₈ groups had the highest and the lowest total length, respectively (p < .05). Moreover, fish exposed to F₄R₁₆ had the highest hepatosomatic indices, while control fish had the lowest hepatosomatic indices (p < .05). Fish in the F₂R₈ group relatively had higher catalase and glutathione‐S‐transferase activities than other groups (p < .05). Furthermore, total protease, α‐amylase and alkaline phosphatase activities in the F₄R₁₆ and F₈R₃₂ were higher than the F₂R₄ and control groups (p < .05). Overall, this study showed that compensatory growth in weight and length and digestive enzyme activities were observed in the F₄R₁₆ and F₈R₃₂; however, the increase in the activity of antioxidant enzymes in the F₈R₃₂ group indicated that oxidative stress remained after 80 days of re‐feeding in the liver.     

Effects of feed ingredients on nutrient digestibility,nitrogen/energy balance and morphology changes in the intestine of Nile tilapia (Oreochromis niloticus)

The present study assessed the effect of different feed ingredients on nutrient apparent digestibility coefficients (ADC), nitrogen/energy balance and morphology changes in the intestine of Nile tilapia; using a control diet and six test diets, in which the following six ingredients were included at 30%: hydrolysed feather meal (HFM), soybean meal (SBM), rice bran (RB), rapeseed meal (RM), sunflower meal (SFM) and dried distillers grains with solubles (DDGS). The proximal, middle and distal intestine was processed for quantitative histology counting the number of goblet cells (GC), and measuring the thickness of lamina propria (LP) and submucosa (SM). The study showed that the ADC of protein in raw materials were highest in SBM (92.2%), followed by SFM (90.2%), DDGS (89.2%), RM (87.8%), HFM (86.9%) and RB (84.0%). The nutrient ADCs had no correlation with intestinal morphology changes. Only the SBM diet caused noticeable changes in intestinal morphology such as an increase the thickness of SM and LP and the number of GC. The diet composition, however, altered the protein efficiency and the maintenance energy requirement. Protein retention efficiency was the lowest in fish fed HFM and the highest in RB. The highest maintenance energy requirements were observed in HFM and SBM treatments.     

Application of synthetic hormone LHRH-A<Subscript>2</Subscript> on the artificial propagation of Persian sturgeon <Emphasis Type="Italic">Acipenser persicus</Emphasis>

For studying the effect of LHRH-A₂ hormone on the induction of final maturation and ovulation of Persian sturgeon, 71 matured females and 20 matured males were used. Five groups of breeders were injected with sturgeon pituitary gland hormone (50 mg per fish) and LHRH-A₂ in dosages of 3.5, 7, 8 and 10 μg kg⁻¹ for females and 3 and 5 μg kg⁻¹ for males. Results showed that LHRH-A₂ successfully induced final maturation and ovulation in females, and there was no significant difference between five groups of breeders in ovulation proportion, fertilization rate, survival rate of incubation, survival of yolk-sac absorption period and active feeding period of larvae. It can be concluded that the LHRH-A₂ is a proper alternative for pituitary gland hormone in artificial propagation of Persian sturgeon.     

The role of Tetrastichus giffardianus Silvestri (Eulophidae: Hymenoptera) in natural control of Bactrocera zonata (Saunders) (Tephritidae: Diptera) and its temporal abundance in Sudan

Bactrocera zonata is an alien fruit fly which was introduced into Sudan in 2012 and spread throughout the country, severely hampering the production and export of fruit and vegetable crops. Cataloguing indigenous natural enemies of pests, especially parasitoids, is key to successful biological control programmes, to mitigate damage and decrease reliance on insecticides. This study was conducted to determine the parasitoids of B. zonata in two orchards in Gezira State, Sudan from November 2015 to May 2016 and from February to December, 2016 and to determine their role in natural control of the pest. Three parasitoids emerged from puparia of B. zonata, these were: Tetrastichus giffardianus Silvestri (Eulophidae), an Aganaspis sp. (Figitidae: Eucoilinae) and a Psyttalia sp. (Braconidae Opiinae). Tetrastichus giffardianus was the most numerous parasitoid throughout the study period. The mean percentages of B. zonata from guava fruits that were parasitized by T. giffardianus for the whole study period were 13.7% and 13.2% with 3.1 ± 0.3 and 2.8 ± 2.4 parasitoids per puparium at Fadasi and Gazirat Elfil sites respectively. Data on the temporal abundance of T. giffardianus is presented. Strenuous efforts should be considered to involve the reported natural enemies of B. zonata in integrated management programmes for fruit flies in Sudan.