A digestive lipase of Pieris brassicae L. (Lepidoptera: Pieridae): purification, characterization, and host plants effects

Purification and characterization of fat body lipase from the Greater Wax MothGalleria mellonella(Lepidoptera: Pyralidae).. [DOI: 10.1101/625129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Lipid mobilization and transport in insects is under investigation, especially lipases and lipophorin because of their roles in energy production and transport of lipids at flying activity. The present study has been conducted to purify intracellular fat body lipase for the first time, from last larval instar ofGalleria mellonella. Purification methods by combination of ammonium sulfate precipitation and gel filtration using Sephadex G-100 demonstrated that the amount of protein and the specific activity of fat body lipase were 0.008633±0.000551 mg/ml and 1.5754±0.1042 μmol/min/mg protein, respectively, with a 98.9 fold purity and recovery of 50.81%. Hence, the sephadex G-100 step was more effective in purification process. SDS-PAGE and zymogram revealed that fat body lipase showed two monomers with molecular weights of 178.8 and 62.6 kDa. Furthermore biochemical characterization of fat body lipase was carried out through testing its activities against several factors such as; different temperatures, pH ranges, metal ions and inhibitors ending by determination of their kinetic parameters with the use ofp-Nitrophenyl butyrate (PNPB) as a substrate. The highest activities of enzyme were determined at the temperature ranges of 35-37°C and 37-40°C and pH ranges of 7-9 and 7–10. The partially purified enzyme showed significant stimulation by Ca2+, K+and Na+metal ions indicating that fat body lipase is metalloproteinase. Additionally, lipase activity was strongly inhibited by some inhibitors; phenylmethylsulfony fluoride (PMSF), ethylene-diaminetetractic acid (EDTA) and ethylene glycoltetraacetic acid (EGTA) providing an evidence of presence of serine residue and activation of enzymes by metal ions. Kinetic parameters were 301.95mM Kmand 0.316 Umg−1Vmax. By considering the purification of fat body lipase from larvae and using some inhibitors especially ion chelating agents, it is suggested to develop this study by using lipase inhibitors to reach a successful control ofGalleria mellonellain the near future.

Structural and Functional Characterization of Hermetia illucens Larval Midgut

The larvae of Hermetia illucens are among the most promising agents for the bioconversion of low-quality biomass, such as organic waste, into sustainable and nutritionally valuable proteins for the production of animal feed. Despite the great interest in this insect, the current literature provides information limited to the optimization of rearing methods for H. illucens larvae, with particular focus on their efficiency in transforming different types of waste and their nutritional composition in terms of suitability for feed production. Surprisingly, H. illucens biology has been neglected and a deep understanding of the morphofunctional properties of the larval midgut, the key organ that determines the extraordinary dietary plasticity of this insect, has been completely overlooked. The present study aims to fill this gap of knowledge. Our results demonstrate that the larval midgut is composed of distinct anatomical regions with different luminal pH and specific morphofunctional features. The midgut epithelium is formed by different cell types that are involved in nutrient digestion and absorption, acidification of the lumen of the middle region, endocrine regulation, and growth of the epithelium. A detailed characterization of the activity of enzymes involved in nutrient digestion and their mRNA expression levels reveals that protein, carbohydrate, and lipid digestion is associated to specific regions of this organ. Moreover, a significant lysozyme activity in the lumen of the anterior and middle regions of the midgut was detected. This enzyme, together with the strong acidic luminal pH of middle tract, may play an important role in killing pathogenic microorganisms ingested with the feeding substrate. The evidence collected led us to propose a detailed functional model of the larval midgut of H. illucens in which each region is characterized by peculiar features to accomplish specific functions. This platform of knowledge sets the stage for developing rearing protocols to optimize the bioconversion ability of this insect and its biotechnological applications.

Biochemical characterization a digestive trypsin in the midgut of large cabbage white butterfly, Pieris brassicae L. (Lepidoptera: Pieridae)

A comprehensive study on digestive trypsin was undertaken in the larval midgut of Pieris brassicae L. Results of enzymatic compartmentalization showed a significantly higher activity of crude trypsin in the anterior larval midgut rather than posterior-midgut. Using Diethylaminoethyl cellulose fast flow column chromatography a purified trypsin was obtained by specific activity of 21 U mg-1 protein, recovery of 22%, purification fold of 28-fold and molecular weight of 25 kDa. This purified enzyme showed the highest activity at pH 8 and the corresponding temperature of 40°C. However, the specific inhibitors used including 4-(2-Aminoethyl) benzenesulfonyl fluroride hydrochloride, N-p-Tosyl-L-lysine methyl ester hydrochloride and Soybean Trypsin Inhibitor significantly lowered the activity of the purified enzyme in vitro. Moreover, the activity of trypsin and likewise the nutritional indices were significantly altered in the larval midgut feeding upon the leaves treated by 1 mM concentration of each inhibitor in comparison with control. Determination of enzymatic characteristics of insect trypsins is crucial in paving the path for controlling pests by potential natural compounds via transgenic plants.

Lipase Activity in the Larval Midgut of Rhynchophorus palmarum: Biochemical Characterization and the Effects of Reducing Agents

Lipases have key roles in insect lipid acquisition, storage, and mobilization and are also fundamental to many physiological processes in insects. Lipids are an important component of insect diets, where they are hydrolyzed in the midgut lumen, absorbed, and used for the synthesis of complex lipids. The South American palm weevil Rhynchophorus palmarum is one of the most important pests on commercial palm plantations. However, there are few studies about lipid digestion for this insect. In this work, we have described the biochemical characterization of the lipase activity in the posterior midgut of the R. palmarum palm weevil. Lipase activity was highest between the temperatures of 37 °C and 45 °C and at pH 6.5. Lipase activity was also sensitive to variations in salt and calcium concentrations. Lipases have been described structurally as enzymes with the Ser-His-Asp Catalytic Triad, containing an active serine. The serine protease inhibitor PMSF (phenylmethane sulfonyl fluoride) inhibited the lipases from R. palmarum, demonstrating the importance of a serine residue for this activity. The ability of the lipases to hydrolyze p-Nitrophenyl esters with different chain lengths has revealed the activities of a broad range of substrates. The lipase activities of R. palmarum increased in the presence of reduced glutathione (GSH) and dithiothreitol (DTT), while in the presence of oxidized glutathione (GSSG), activities were drastically reduced. To our knowledge, this study has provided the first information about lipase activity in the R. palmarum palm weevil.

Expression and characterization of a lipase-related protein in the malpighian tubules of the Chinese oak silkworm, Antheraea pernyi

Lipases are ubiquitous enzymes in nature, which play a crucial role in fat metabolism by catalyzing the hydrolysis of triacylglycerol to free fatty acids and glycerol. However, reports concerning insect lipase are rare. In this study, we studied the expression and activity of a lipase-related protein from Antheraea pernyi (ApLRP). Recombinant ApLRP was expressed in Escherichia coli cells and used to raise rabbit anti-ApLRP polyclonal antibodies. ApLRP mRNA and protein expression were abundant in the midgut and malpighian tubules, respectively. After challenge with four different microorganisms (E. coli, Beauveria bassiana, Micrococcus luteus and nuclear polyhedrosis virus), the expression levels of ApLRP mRNA in midgut were inducted significantly compared with the control. The different pathogens induced different ApLRP gene expression patterns. The optimum temperature and pH for the enzyme's activity were 35°C and 7.0, respectively. ApLRP activity was stimulated in the presence of Mg2+, Na+, Ca2+ and b-mercaptoethanol; while Zn2+, Cu2+ and Fe3+ inhibited its activity. Detergents such as SDS, glycerol and Tween-20 increased the lipase activity by 20-30%. Our results indicated that ApLRP might play an important role in the innate immunity of insects.