Characterisation of digestive protease in the rose sawfly,Arge rosae Linnaeus (Hymenoptera: Argidae)

Insect midgut proteases are excellent targets for insecticidal agents such as protease inhibitors. These inhibitors are used for producing transgenic plants, resistant to pests. For achieving this goal, it is necessary to find the nature of specific proteases and their properties for adopting possible pest management procedure. Therefore, characterisation of the enzymes in the gut of the rose sawfly, Arge rosae (Hymenoptera: Argidae), responsible for proteolysis, was performed using a range of synthetic substrates and specific inhibitors. The optimum conditions for general proteases and trypsin were achieved at pH 10. The highest activity for general proteases was obtained at a temperature of 45°C. The use of specific inhibitors and SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis) provided evidence to suggest that most of the proteases belonged to the serine group because of high inhibitory effect of phenyl methane sulfonyl fluoride on total proteolytic activity. Also, inhibition assays and zymogram analysis showed that metalloproteases are present in A. rosae digestive system. These results indicated that A. rosae larvae mainly used serine proteases for protein digestion, with chymotrypsin as the dominant form. The kinetic parameters of trypsin-like proteases using N-benzoyl-dl-arg-p-nitroanilide as substrate indicated that the K _m and V _max values of trypsin in the gut of the fifth instar larvae were 730 ± 17.3 μM and 456 ± 13.85 nmol min^?1 mg^?1 protein, respectively.     

Melatonin: An important anticancer agent in colorectal cancer

Colorectal cancer is one of the most common cancers among the elderly, which is also seen in the forms of hereditary syndromes occurring in younger individuals. Numerous studies have been conducted to understand the molecular and cellular pathobiology underlying colorectal cancer. These studies have found that cellular signaling pathways are at the core of colorectal cancer pathology. Because of this, new agents have been proposed as possible candidates to accompany routine therapy regimens. One of these agents is melatonin, a neuro-hormone known best for its essential role in upholding the circadian rhythm and orchestrating the many physiologic changes it accompanies. Melatonin is shown to be able to modulate many signaling pathways involved in many essential cell functions, which if deregulated cause an accelerated pace towards cancer. More so, melatonin is involved in the regulation of immune function, tumor microenvironment, and acts as an antioxidant agent. Many studies have focused on the beneficial effects of melatonin in colorectal cancers, such as induction of apoptosis, increased sensitivity to chemotherapy agents and radiotherapy, limiting cellular proliferation, migration, and invasion. The present review aims to illustrate the known significance of melatonin in colorectal cancer and to address possible clinical use.     

Immobilization of lipases onto the SBA-15 mesoporous silica

Lipase is an important enzyme which can catalyse the hydrolysis of lipids and has several applications and industrial potentials. In addition, different types of lipases are used as efficient catalysts in the enantioselective esterification and/or hydrolysis reactions and produce products in high yields and enantio excess as well. However, immobilization of lipases on the surface of a heterogeneous substrate is necessary to improve its specific catalytic activities as it can be isolated from the reaction mixture easily. Mesoporous silica materials are the best option for this aim due to their high specific surface area, ordered structure, and large pore volume. Hence, in this article, the role of SBA-15 and the modified SBA-15 mesoporous materials as support for different lipases and their catalytic activities are reviewed.     

Sublethal effects of Thymus vulgaris essential oil on life-table parameters of two-spotted spider mite,Tetranychus urticae Koch (Acari: Tetranychidae)

Sublethal effects of Thymus vulgaris were investigated on life-table parameters of Tetranychus urticae Koch (Acari: Tetranychidae) in the laboratory conditions at 25?±?1?°C, 70?±?10% RH and a 14:10?h (L:D) photoperiod. Bioassay was conducted to assess the effect of different concentrations of T. vulgaris essential oil on two-spotted spider mite. LC₅₀ and LC₂₀ of T. vulgaris on T. urticae were calculated as 18.86 and 6.24?μl/litre air for 24?h after treatment. In the sublethal effects, after 24?h exposure to LC₅₀ concentration, mortality, fecundity and longevity of the females that survived from treatment were determined. Results showed that T. vulgaris caused significant reductions in fecundity and longevity of adults. Life-table assay indicated that the intrinsic rate of increase (r _m), net reproductive rate (R ₀), finite rate of increase (λ), mean generation time (T), significantly reduced in treated females compared to control. These results suggest that T. vulgaris could be incorporated in integrated pest management programmes of T. urticae.     

Genetic and in silico analysis of plantaricin EFI locus in indigenous isolates of lactobacillus plantarum

Genetic investigation and in silico analysis of plantaricin EFI (plnEFI) locus was performed in three indigenous isolates of Lactobacillus plantarum EL3, L28 and BL1. Amplification with plnEFI specific primers and production of ~ 10 KDa size protein suggested the existence of class II bacteriocins. The analysis demonstrated that the studied fragment included structural bacteriocin, immunity, partial transporter and potential regulatory encoding regions. Based on the results, there was one DNA polymorphic site in plnE as well as plnF of the studied sequences. One nucleotide substitution in plnE of BL1 isolate lead to replacement of Glycin with Valine. These two are of non-polar type which did not affect instability index of plnE protein. The only nucleotide variation in plnF of EL3 isolate did not change the amino acid sequence since the modified nucleotide constituted alternative codon of the original amino acid. The highest DNA polymorphism occurred in the region with immunity function which in BL1 resulted in the conversion of start codon to amino acid codon. In the partial transporter sequence, one variable nucleotide site caused amino acid replacement in all the isolates which elevated stability of N-terminal domain in the transporter protein compared to nominated reference isolate L. plantarum C11. The region with possible regulatory function was identical in all three isolates. © 2018 American Institute of Chemical Engineers Biotechnol Progress, 35: e2773, 2019.