Molecular cloning and 3D model of first cytochrome P450 from CYP3A subfamily in saltwater crocodile (Crocodylus porosus)

Biotransformation of carbamazepine and nicotine in juvenile American alligator (Alligator mississippiensis) in vitro hepatic S9 vs. in situ perfused liver

American alligators (Alligator mississippiensis) are apex predators and sentinel species in the coastal wetland ecosystem along the Gulf of Mexico. There is concern for alligator exposure and susceptibility to chemical contaminants due to their high trophic level and lower metabolic capability. At present, their hepatic biotransformation capacity to metabolize or detoxify contaminants has not been comprehensively determined. In this study, the hepatic biotransformation capability of juvenile American alligators to metabolize two commonly found environmental pharmaceuticals: carbamazepine (CBZ) or nicotine (NCT) was evaluated. The formation of their respective primary metabolites, i.e., carbamazepine-10,11-epoxide (CBZ-E) and cotinine (CTN), was evaluated at 10 μM (within the human therapeutic range). The in vitro S9 and a novel in situ liver perfusion assays were used to characterize and compare metabolic ability in isolated hepatic enzymes vs. whole organ (liver). For CBZ, the perfused livers exhibited only 30% of intrinsic formation clearance (CLf,int) relative to the S9 assay. The metabolism of NCT was not detectable in the S9 assay and was only observed in the perfused liver assay. Compared to the corresponding rat models (S9 or perfused livers),alligators' CLf,int was 2060% for CBZ and 50% for NCT of rats. Additionally, NCT exposure increased lactate levels in perfused livers indicating metabolic stress. This study provides insight into the hepatic capability of alligators to metabolize CBZ and NCT using an established in vitro (S9) system and a newly developed in situ liver perfusion system.

Transient Expression in Cytoplasm and Apoplast of Rotavirus VP6 Protein Fused to Anti-DEC205 Antibody in Nicotiana benthamiana and Nicotiana sylvestris

Rotavirus is the most common cause of severe diarrhea in infants and children worldwide and is responsible for about 215,000 deaths annually. Over 85% of these deaths originate in low-income/developing countries in Asia and Africa. Therefore, it is necessary to explore the development of vaccines that avoid the use of "living" viruses and furthermore, vaccines that have viral antigens capable of generating powerful heterotypic responses. Our strategy is based on the expression of the fusion of the anti-DEC205 single-chain variable fragment (scFv) coupled by an OLLAS tag to a viral protein (VP6) of Rotavirus in Nicotiana plants. It was possible to express transiently in N. benthamiana and N. sylvestris a recombinant protein consisting of the single chain variable fragment linked by an OLLAS tag to the VP6 protein. The presence of the recombinant protein, which had a molecular weight of approximately 75 kDa, was confirmed by immunodetection, in both plant species and in both cellular compartments (cytoplasm and apoplast) where it was expressed. In addition, the recombinant protein was modeled, and it was observed that some epitopes of interest are exposed on the surface, which could favor their immunogenic response.

Identification and characterization of a new cry-like gene found in a Bacillus cereus strain

Bacillus thuringiensis is the most successful microbial insecticide against different pests in agriculture and vectors of diseases. Its activity is mostly attributed to the Cry proteins expressed during its sporulation phase. However, these proteins are not exclusive to B. thuringiensis. Some cry genes have been found in other Bacillus species, or even in other genera. In this work, cry genes were searched in 223 acrystalliferous bacillaceous strains. From these strains 13 amplicons were obtained, cloned, and sequenced; however, only 6 amplicons tested positive for cry-like genes, and the 6 isolates showed to be the same strain. We report the characterization of an unusual strain of B. cereus (LBIC-004) which is unable to form protein inclusions during the sporulation phase. LBIC-004 showed a high identity to B. cereus using the sequences of 16S rRNA, gyrB and hag genes; in addition, a unique plasmid pattern of the strain was obtained. A 1953-bp cry gene was identified, coding for a 651 amino acid protein with a molecular weight of 74.9 kDa. This protein showed a predicted three-domain structure, similar to all Cry proteins. However, the amino acid sequence of the protein showed only 41% identity its highest hit: the Cry8Ca1 protein, indicating the uniqueness of this cry-like gene. It was cloned and transferred into a mutant acrystalliferous B. thuringiensis strain which was used in bioassays against Caenorhabditis elegans, Aedes aegypti, Manduca sexta and Phyllophaga sp. The recombinant strain showed no crystal formation and no toxicity to the tested species.