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Background The production of industrial enzymes such as xylanase using sufficient cost-effective substrates from potent microorganisms is considered economically feasible. Studies have reported castor cake (Ricinus communis) as the most potent and inexpensive alternative carbon source for production of xylanase C by using Aspergillus terreus (A. terreus). Results A. terreus strain RGS Eg-NRC, a local isolate from agro-wastes, was first identified by sequencing the internal transcribed spacer region of a nuclear DNA encoding gene cluster deposited in GenBank (accession number MW282328). Before optimization of xylanase production, A. terreus produced 20.23 U/g of xylanase after 7 days using castor cake as a substrate in a solid-state fermentation (SSF) system that was employed to achieve ricin detoxification and stimulate xylanase production. Physicochemical parameters for the production of xylanase were optimized by using a one-variable-at-a-time approach and two statistical methods (two-level Plackett–Burman design and central composite design, CCD). The maximum xylanase yield after optimization was increased by 12.1-fold (245 U/g). A 60–70% saturation of ammonium sulfate resulted in partially purified xylanase with a specific activity of 3.9 IU/mg protein. At 60 °C and pH 6, the partially purified xylanase had the highest activity, and the activation energy (Ea) was 23.919 kJmol. Subsequently, antioxidant capacity and cytotoxicity tests in normal Ehrlich ascites carcinoma human cells demonstrated xylooligosaccharides produced by the xylanase degradation of xylan as a potent antioxidant and moderate antitumor agent. Further investigations with sodium dodecyl sulfate polyacrylamide gel electrophoresis then determined the molecular weight of partially purified xylanase C to be 36 kDa. Based on the conserved regions, observations revealed that xylanase C belonged to the glycosyl hydrolase family 10. Next, the xylanase-encoding gene (xynC), which has an open reading frame of 981 bp and encodes a protein with 326 amino acids, was isolated, sequenced, and submitted to the NCBI GenBank database (accession number LC595779.1). Molecular docking analysis finally revealed that Glu156, Glu262, and Lys75 residues were involved in the substrate-binding and protein-ligand interaction site of modeled xylanase, with a binding affinity of −8.7 kcal. mol−1. Conclusion The high production of safe and efficient xylanase could be achieved using economical materials such as Ricinus communis.

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The present investigation reports the possible protective effect of β-carotene against hepatic lesions induced in male albino rats due to γ-irradiation. 48 male albino rats were divided into three main groups; the first group served as control (12 rats). Rats of the second group (18 rats) were exposed to a sub-lethal dose of whole body γirradiation and then divided into three equal subgroups. The rats of the third main group (18 rats) received 5mg/kg body wt of β-carotene at a daily oral dose for 2 consecutive weeks, and were then subjected to whole body γ-irradiation at sub-lethal single dose level of 6Gy (Gray). This group was then divided into three equal subgroups. The rats were autopsied at three intervals; one week, two weeks and four weeks post irradiation. The obtained data revealed that γ-irradiation-induced different histological changes in the liver of irradiated rats. These changes varied from haemorrhage, congestion in blood vessels, pyknosis and necrosis as well as complete degenerated areas in the liver. Electron micrographs recorded swollen mitochondria, fragmented endoplasmic reticulum, distorted nuclei and cell membrane and lipid infiltration in the hepatocytes of irradiated animals. The treatment with βcarotene (5 mg/ kg body wt for two consecutive weeks) pre-exposure to radiation attenuated most of these changes. Therefore, the present study has concluded the potential use of β-carotene dissolved in corn oil as a radio protector.

Root-knot nematode is one of the major problems that face the agricultural production of several vegetable crops. Chemical nematicides have been banned because of their healthy and environmental undesirable attributes. So, this study aimed to evaluate the potential use of sweet annie (Artimisia annua) and garden cress (Lepidium sativum) as green routes for the development of effective and eco-friendly alternative nematicides. Nematicidal activity of sweet annie and garden cress aqueous extracts (500 g/L) in the original and nano-forms were evaluated against Meloidogyne incognita in tomato planted in infected soil under greenhouse conditions. Nineteen phenolic compounds were identified in A. annua extract, which was dominated by chlorogenic acid (5059 µg/100 mL), while 11 compounds were identified in L. sativum extract, that dominated by p-hydroxybenzoic acid (3206 μg/100 mL). Nano-particles were characterized with smooth surface, spherical shape and small size (50–100 nm). Under laboratory, the nano-formulations showed mortality percentage of M. incognita J2 greater than the original extract from. Vegetative growth parameters of tomato plants treated with A. annua and L. sativum extracts significantly improved compared to the control plants. Also, biochemical analysis revealed that the extracts were able to induce tomato plants towards the accumulation of phenolic compounds and increasing the activity of defensive enzymes (protease, polyphenol oxidase and chitinase) resulting in systemic resistance. Regarding tomato fruits yield and quality, the studied treatments significantly improved the yield and physicochemical parameters of tomato fruits in terms of fruit weight, diameter, TSS, pH, lycopene content and color attributes gaining higher sensorial acceptance by the panelist. Generally, both extracts represent promising nematicide alternatives and have potential use in crop management. The nano-form of A. annua extract outperformed the nematicidal activity of other studied treatments.

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Root-knot nematodes (RKN), Meloidogyne incognita, caused significant problems for many important crops. Measuring control with low environmental impact has been required since EU legislation revised pesticide laws for crops. Bacteria-based control methods reduce pollutants and stabilise ecological changes, which makes them promising for controlling plant pathogens. In this study, the derivative of Bacillus subtilis168, termed Bs118, was generated by replacing the native promoter of the extracellular neutral metalloprotease-encoding gene (nprE) with a constitutive promoter of the repU gene responsible for replication of the Staphylococcus aureus plasmid pUB110. As a result, protease production increased to twice that of the wild type. Results revealed that the overproduction of neutral metalloprotease conferred Bs118 high nematocidal activity by inducing 98% mortality in the M. incognita J2 in vitro study. Bs118 stated its priority in affecting root-knot nematode reproduction under greenhouse conditions. The soil drench treatment was more promising than root dipping in controlling M. incognita compared with the untreated control treatment. The same trend happened in the eggplant growth parameters, where Bs118 improved plant health more than Bs168. In conclusion, site-directed mutation via homologous recombination to replace the native promoter with another constitutive one is a promising approach to constructing modified strains with higher protease production that can be employed as an efficient biocontrol agent against root-knot nematodes in addition to the positive impacts on plant growth.