The basic isoelectric form of alpha-L-fucosidase from the hepatopancreas of the shrimp Penaeus monodon (Crustacea: Decapoda)

Effects of cypermethrin on the hepatic transcriptome and proteome of the red claw crayfish Cherax quadricarinatus

Cypermethrin (CYP) is a synthetic pyrethroid broadly used for pest control, however, it is extremely toxic to aquatic organisms. To assess the toxicity of CYP in red claw crayfish Cherax quadricarinatus, transcriptional and proteomic approaches combining two-dimensional polyacrylamide gel electrophoresis and tandem mass spectrometry were used to compare the hepatic expression profiles. A total of 41,349 unigenes and 8839 differentially expressed genes (DEGs) were obtained, which were enriched in the process. The category of 779 (0.625 ng L^-1 CYP vs Con), 1963 (1.25 vs Con), and 2066 (1.25 vs 0.625) DEGs were screened. All findings suggested that CYP can induce antioxidant and biotransformation modulation variations in C. quadricarinatus to resist immunotoxicity and oxidative damages. The category of 196 (0.625 ng L^-1 CYP vs Con) specific proteins were differentially expressed: 24 proteins were upregulated, and 20 proteins were downregulated relative to CYP. Protein identification indicated the KEGG pathways of the human immunodeficiency virus 1 infection, insulin signaling pathway, and influenza A enriched. From the differential expression of the selected nine proteins, the increased Loc113824800, Rps19, Atp2, Rps10, Hsp40, Brafldraft_124327, and the decreased Loc117331934, Loc113213835, and Loc106806551 revealed. While for the verification of the eight genes in transcriptome and the above nine genes in proteomic, specifically, gpx5, ggt, loc106458463, chelonianin decreased in the 0.625 ng L^-1 CYP group. The transcripts of loc113816050, akr1d1 and gst, chelonianin and loc108675455 decreased and increased in the 1.25 ng L^-1 CYP group, respectively. The present study reflects the overall change in cellular structure and metabolism related to the resistance of pyrethroid insecticides.

First characterization of fucosidases in spiders

l-fucose is a constituent of glycoconjugates in different organisms. Fucosidases catalyze the removal of fucose residues, and have been correlated to different physiological and pathological processes, such as fertilization, cancer, fucosidosis, and digestion in molluscs and ticks. An α-l-fucosidase sequence was identified from the transcriptome and proteome from the midgut diverticula of the synanthropic spider Nephilingis cruentata. In this article, we describe the isolation of this α-l-fucosidase and the characterization of its activity using substrates and inhibitors demonstrating different specificities among fucosidases. The enzyme had a K_m of 32 and 400 μM for 4-methylumbelliferyl α-l-fucopyranoside and 4-nitrophenyl α-l-fucopyranoside, respectively; and was unable to hydrolyze fucoidan. Nephilingis cruentata α-l-fucosidase was inhibited competitively by fucose and fuconojyrimycin. The fucosidase had two distinct pH optima even in the isolated form, due to oligomerization dependent on pH, as previously described to other fucosidases. Alignment and molecular homology modeling of the protein sequence with other fucosidases indicated that the active sites and catalytic residues were different, including residues involved in acid/base catalysis. Phylogenetic analysis showed, for the first time, gene-duplication events for fucosidases in Arachnida species. All these data reveal that studies on fucosidases in organisms distinct from bacteria, fungi, and humans are important.

Carbohydrate digestion in ticks and a digestive α-L-fucosidase

Digestive carbohydrases are present in many species of hematophagous Arthropoda, including ticks. In this work, Amblyomma cajennense (Ixodidae) midgut digestive carbohydrases were tracked with different substrates, resulting in the identification of a chitinase and an N-acetyl-β-glucosaminidase and the first description of a digestive α-L-fucosidase in ticks. α-L-fucosidases are involved in various physiological processes, and digestive α-L-fucosidases have been shown to be present in other types of organisms. Amblyomma cajennense α-L-fucosidase activity was isolated using acidic and salting-out precipitations and chromatographic steps in hydrophobic and cation-exchange columns. The specificity of the isolated activity as an α-L-fucosidase was confirmed by the hydrolysis of 4-methylumbelliferyl α-L-fucopyranoside and the natural substrate fucoidan and the inhibition by fucose and deoxyfuconojirimycin. The isolated activity of α-L-fucosidase forms oligomers with molecular mass of 140 kDa or 150 kDa as determined by gel filtration and non-reducing SDS-PAGE, respectively. This particular fucosidase has an optimum pH of 5.3, is stable even at high temperatures (stable for at least 2h at 50 °C), has a Km of 45 μM to the substrate 4-methylumbelliferyl α-L-fucopyranoside and IC 50% of 327 μM to fucose and 42 pM to deoxyfuconojirimycin. The presence of digestive fucosidases in hematophagous Arthropoda may be related to defence mechanisms against host-parasite interactions.