CDNAs coding for five procathepsin L-like proteinases (pCALs) were cloned and sequenced from a cDNA library prepared from Tenebrio molitor larval midguts: pCAL1a (with the isoforms pCAL1b and pCAL1c), pCAL2, and pCAL3. All the pCALs have the active residues Cys 25, His 169, Asn 175, and Gln 19 (papain numbering), the ERFNIN motif of papain-like enzymes and their sequences are homologous to cathepsin L enzymes. pCAL1a was expressed in bacterial systems. It is auto-catalytically activated at low pH, has kinetic properties and N-terminal sequence identical to hemocyte cathepsin L-like proteinase (CAL) and was used to raise antibodies. Semi-quantitative RT-PCR data showed that mRNAs for pCAL2 and pCAL3 were transcribed in midgut and in lesser amounts in hemolymph, whereas that for pCAL1a was transcribed in these tissues and also in fat body, Malpighian tubules, and carcass. Imunochemical detection recognized pCAL1a translation in all tissue homogenates, except anterior midgut. At this region, the presence of pCAL2 is suggested on the grounds of electrophoretical migration and high recovery of CAL2 activity from anterior midgut cells and from isolated midgut contents. Immunocytochemical localization data revealed that pCAL1a occurs in lysosome-like vesicles in all tissues, except anterior midgut, where a labelling considered to correspond to pCAL2 is found in large acidic granules being released by apocrine secretion. Putative pCAL2 was also detected in midgut contents, probably in the form of CAL2, the major luminal CAL, which was purified to homogeneity. A cladogram of insect CALs result in a monophyletic branch with lysosomal T. molitor enzymes and enzymes from five insect orders and in a polyphyletic array of coleopteran sequences, including digestive CALs from T. molitor. The data suggest that only Coleoptera have digestive CALs that may originate by gene duplication and independent evolution relative to the gene encoding the lysosomal enzyme.
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http://dx.doi.org/10.1016/j.ibmb.2005.03.006 | DOI Listing |
Int J Mol Sci
December 2024
Liaoning Engineering and Technology Research Center for Insect Resources, College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang 110866, China.
Chitin deacetylases (CDAs) are carbohydrate esterases associated with chitin metabolism and the conversion of chitin into chitosan. Studies have demonstrated that chitin deacetylation is essential for chitin organization and compactness and therefore influences the mechanical and permeability properties of chitinous structures, such as the peritrophic membrane (PM) and cuticle. In the present study, two genes ( and ) encoding CDA protein isoforms were identified and characterized in Chinese oak silkworm () larvae.
View Article and Find Full Text PDFJ Hazard Mater
January 2025
School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon 999077, Hong Kong; Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China. Electronic address:
The plastivore insect Tenebrio molitor demonstrates significant potential for the rapid biodegradation and bioremediation of micro(nano)plastics. However, real-time visualization of the digestive degradation and removal of microplastics (MPs) during intestinal transit, along with the associated in vivo intestinal functional responses, remains challenging. Here, we developed second near-infrared (NIR-II) window aggregated-induced emission (AIE) MPs of two sizes (29.
View Article and Find Full Text PDFFolia Morphol (Warsz)
December 2024
Department of Anatomy, Division of Basic Medicine, Tokai University School of Medicine, Isehara, Japan.
Background: The superior mesenteric vein appears as a fusion between irregularly-shaped slits of the midgut mesentery tissue at 5-6 weeks. In contrast, there might be no report when and how the inferior mesenteric vein (IMV) develops. We aimed to find the human initial IMV.
View Article and Find Full Text PDFEcotoxicol Environ Saf
December 2024
Hubei International Scientific and Technological Cooperation Base of Waste Conversion by Insects, Huazhong Agricultural University, Wuhan 430070, China. Electronic address:
The black soldier fly larvae (BSFL) is a highly valued resource insect, renowned for its efficient and eco-friendly approach to the treatment of organic waste. A crucial matter that demands clarification is whether the heavy metals are eliminated or remain within BSFL bodies. Our research focused on the toxicokinetic and the dynamic tissue changes of cadmium (Cd) in BSFL exposed to low (50 mg/kg), moderate (300 mg/kg), and high levels (700 mg/kg) of Cd stress, with the goal of offering a novel perspective on this matter.
View Article and Find Full Text PDFJ Biol Inorg Chem
December 2024
Departamento de Fisiología, Biofísica y Neurociencias, Cinvestav, 07360, Mexico City, Mexico.
The rise of atmospheric oxygen as a result of photosynthesis in cyanobacteria and chloroplasts has transformed most environmental iron into the ferric state. In contrast, cells within organisms maintain a reducing internal milieu and utilize predominantly ferrous iron. Ferric reductases are enzymes that transfer electrons to ferric ions, either extracellularly or within endocytic vesicles, enabling cellular ferrous iron uptake through Divalent Metal Transporter 1.
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