Instituto Butantan 2 articles published in JoVE Biology Captive Maintenance and Venom Extraction of Tityus serrulatus (Brazilian Yellow Scorpion) for Antivenom Production Thiago M. Chiariello1, Denise M. Candido1, Ricardo N. Oliveira1, Aline V. V. Auada1, Fan Hui Wen1 1Bioindustrial Center, Instituto Butantan Here, we present successful maintenance and venom extraction protocols for large-scale Tityus serrulatus Lutz and Mello, 1922 (Brazilian yellow scorpion) husbandry, with the aim of providing venom for subsequent scorpion antivenom production to meet the demand of the Brazilian health system. Genetics Application of CRISPR Interference (CRISPRi) for Gene Silencing in Pathogenic Species of Leptospira L. G. V. Fernandes1,2, R. L. Hornsby1, A.L.T.O. Nascimento*2, J. E. Nally*1 1Infectious Bacterial Diseases Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, 2Laboratório de Desenvolvimento de Vacinas, Instituto Butantan Here, the application of CRISPR interference (CRISPRi) for specific gene silencing in Leptospira species is described. Leptospira cells are transformed by conjugation with plasmids expressing dCas9 (catalytically "dead" Cas9) and a single-guide RNA (sgRNA), responsible for base pairing to the desired genomic target. Methods to validate gene silencing are presented.