Scorpine‐like peptides are two domain peptides found in different scorpion venoms displaying various antimicrobial, cytolytic, and potassium channel‐blocking activities. The relative contribution of each domain to their different activities remains to be elucidated. Here, we report the recombinant production, solution structure, and antiparasitic activity of Hge36, first identified as a naturally occurring truncated form of a Scorpine‐like peptide from the venom of Hoffmannihadrurus gertschi. We also show that removing the first four residues from Hge36 renders a molecule with enhanced potassium channel‐blocking and antiparasitic activities. Our results are important to rationalize the structure‐function relationships of a pharmacologically versatile molecular scaffold.
Taenia soliumthioredoxin-1 gene (TsTrx-1) has a length of 771 bp with three exons and two introns. The core promoter gene presents two putative stress transcription factor binding sites, one putative TATA box, and a transcription start site (TSS). TsTrx-1 mRNA is expressed higher in larvae than in adult. This gene encodes a protein of 107 amino acids that presents the Trx active site (CGPC), the classical secondary structure of the thioredoxin fold, and the highest degree of identity with theEchinococcus granulosusTrx. A recombinant TsTrx-1 (rTsTrx-1) was produced inEscherichia coliwith redox activity. Optimal activity for rTsTrx-1 was at pH 6.5 in the range of 15 to 25°C. The enzyme conserved activity for 3 h and lost it in 24 h at 37°C. rTsTrx-1 lost 50% activity after 1 h and lost activity completely in 24 h at temperatures higher than 55°C. Best storage temperature for rTsTrx-1 was at −70°C. It was inhibited by high concentrations of H2O2and methylglyoxal (MG), but it was inhibited neither by NaCl nor by anti-rTsTrx-1 rabbit antibodies that strongly recognized a ~12 kDa band in extracts from several parasites. These TsTrx-1 properties open the opportunity to study its role in relationshipT. solium-hosts.
TATA-box binding protein (TBP) is an essential regulatory transcription factor for the TATA-box and TATA-box-less gene promoters. We report the cloning and characterization of a full-length cDNA that encodes a Taenia solium TATA-box binding protein 1 (TsTBP1). Deduced amino acid composition from its nucleotide sequence revealed that encodes a protein of 238 residues with a predicted molecular weight of 26.7 kDa, and a theoretical pI of 10.6. The NH2-terminal domain shows no conservation when compared with to pig and human TBP1s. However, it shows high conservation in size and amino acid identity with taeniids TBP1s. In contrast, the TsTBP1 COOH-terminal domain is highly conserved among organisms, and contains the amino acids involved in interactions with the TATA-box, as well as with TFIIA and TFIIB. In silico TsTBP1 modeling reveals that the COOH-terminal domain forms the classical saddle structure of the TBP family, with one α-helix at the end, not present in pig and human. Native TsTBP1 was detected in T. solium cysticerci´s nuclear extract by western blot using rabbit antibodies generated against two synthetic peptides located in the NH2 and COOH-terminal domains of TsTBP1. These antibodies, through immunofluorescence technique, identified the TBP1 in the nucleus of cells that form the bladder wall of cysticerci of Taenia crassiceps, an organism close related to T. solium. Electrophoretic mobility shift assays using nuclear extracts from T. solium cysticerci and antibodies against the NH2-terminal domain of TsTBP1 showed the interaction of native TsTBP1 with the TATA-box present in T. solium actin 5 (pAT5) and 2-Cys peroxiredoxin (Ts2-CysPrx) gene promoters; in contrast, when antibodies against the anti-COOH-terminal domain of TsTBP1 were used, they inhibited the binding of TsTBP1 to the TATA-box of the pAT5 promoter gene.
Taenia solium can cause human taeniasis and/or cysticercosis. The latter can in some instances cause human neurocysticercosis which is considered a priority in disease‐control strategies and the prevention of mental health problems. Glutathione transferases are crucial for the establishment and long‐term survival of T. solium; therefore, we structurally analyzed the 24‐kDa glutathione transferase gene (Ts24gst) of T. solium and biochemically characterized its product. The gene promoter showed potential binding sites for transcription factors and xenobiotic regulatory elements. The gene consists of a transcription start site, four exons split by three introns, and a polyadenylation site. The gene architecture is conserved in cestodes. Recombinant Ts24GST (rTs24GST) was active and dimeric. Anti‐rTs24GST serum showed slight cross‐reactivity with human sigma‐class GST. A 3D model of Ts24GST enabled identification of putative residues involved in interactions of the G‐site with GSH and of the H‐site with CDNB and prostaglandin D2. Furthermore, rTs24GST showed optimal activity at 45 °C and pH 9, as well as high structural stability in a wide range of temperatures and pHs. These results contribute to the better understanding of this parasite and the efforts directed to fight taeniasis/cysticercosis.
Diabetes type 2 (DT2) entails significant health, economic, and productivity repercussions around the world. Poor glycaemic control, defined as an HbA1c >7.0%, has been associated with a number of complications. In spite of the large share of healthcare resources allocated to DT2 treatment, the proportion of controlled Mexican patients is among the lowest in the world (34.4%). Certain protein-encoding genetic polymorphisms involved in metformin transport may affect glycaemic control. We focused on determining the frequency of rs2289669, rs2252281, rs12943590, and rs34834489 polymorphisms in Mexican-Mestizo patients from the Tertiary Care Regional Hospital of Ixtapaluca, State of Mexico, Mexico, as well as assessing their possible association with therapeutic efficacy, as estimated through glycated haemoglobin. The individual polymorphism analysis did not reveal an association with glycaemic control; however, when combined with rs72552763 and rs622342, we found a significant positive correlation between HbA1c levels and metformin dose, which prevailed among patients carrying allelic variants of rs2289669 or rs12943590 who were also simultaneously carrying allelic variants of rs72552763 or rs622342. Patients carrying the reference allele of rs34834489 reported a significant positive correlation between HbA1c levels and metformin dose as well, regardless of their rs72552763 or rs622342 genotype. Thus, we identified alleles and allelic combinations of SLC47A1, SLC47A2, and SLC22A1 polymorphisms posing a potential glycaemic control risk in Mexican-Mestizo patients.
The genus Taenia belongs to the class Cestoda and comprises a diverse group of species of medical, veterinary, and ecological importance. These tapeworms exhibit complex life cycles involving carnivorous definitive hosts and herbivorous or omnivorous intermediate hosts. Taenia solium, T. saginata, and T. asiatica are particularly important due to their impact on human health, notably through taeniasis and cysticercosis. Mitochondrial genomes (mitogenomes) have emerged as powerful tools for taxonomy, diagnostics, and evolutionary studies of these parasites. Complete mitogenome sequences are available for several Taenia species, revealing conserved structures and a compact genome, including 12 protein-coding genes, 22 tRNAs, and 2 rRNAs, along with species-specific variations in initiation and termination codons. Beyond taxonomy, mitochondrial targets offer a promising avenue for antiparasitic drug development, especially genes related to oxidative phosphorylation and ATP synthesis.