Papers by Sabrina Teixeira
Peptides, 2008
p e p t i d e s 2 9 ( 2 0 0 8 ) 1 6 4 5 -1 6 5 6 Microbicide Bothrops brazili Synthetic peptides ... more p e p t i d e s 2 9 ( 2 0 0 8 ) 1 6 4 5 -1 6 5 6 Microbicide Bothrops brazili Synthetic peptides Phospholipases A 2 Myotoxins Snake venom a b s t r a c t This paper reports the purification and biochemical/pharmacological characterization of two myotoxic phospholipases A 2 (PLA 2 s) from Bothrops brazili venom, a native snake from Brazil. Both myotoxins (MTX-I and II) were purified by a single chromatographic step on a CM-Sepharose ion-exchange column up to a high purity level, showing M r $ 14,000 for the monomer and 28,000 Da for the dimer. The N-terminal and internal peptide amino acid sequences showed similarity with other myotoxic PLA 2 s from snake venoms, MTX-I belonging to Asp49 PLA 2 class, enzymatically active, and MTX-II to Lys49 PLA 2 s, catalytically inactive. Treatment of MTX-I with BPB and EDTA reduced drastically its PLA 2 and anticoagulant activities, corroborating the importance of residue His48 and Ca 2+ ions for the enzymatic catalysis. Both PLA 2 s induced myotoxic activity and dose-time dependent edema similar to other isolated snake venom toxins from Bothrops and Crotalus genus. The results also demonstrated that MTXs and cationic synthetic peptides derived from their 115-129 Cterminal region displayed cytotoxic activity on human T-cell leukemia (JURKAT) lines and microbicidal effects against Escherichia coli, Candida albicans and Leishmania sp. Thus, these PLA 2 proteins and C-terminal synthetic peptides present multifunctional properties that might be of interest in the development of therapeutic strategies against parasites, bacteria and cancer.
Journal of Venomous Animals and Toxins Including Tropical Diseases, 2007
This work succinctly describes the professional and scientific life of Dr. José R. Giglio, one of... more This work succinctly describes the professional and scientific life of Dr. José R. Giglio, one of the most outstanding Brazilian researchers in the field of Toxinology. During his long and successful career, he has made major contributions, especially in elucidating the function, structure, and mechanisms of action of animal venom proteins (from snakes, scorpions and spiders) as well as the characterization of antibodies and several inhibitors of venoms and toxins. We present here a brief history of Dr. Giglios personal and professional life, also reporting some of his numerous published scientific articles on venoms from snakes (Bothrops, Crotalus, and other genera), scorpions (Tityus sp), spiders (Phoneutria sp), their isolated toxins and natural inhibitors. Thus, this work is a tribute to Dr. Giglio in his 73rd birthday, having devoted 48 years of his life studying animal venoms, an effort that has continued even after his formal retirement from university duties.
Archives of Toxicology
This paper describes a biochemical and pharmacological characterization of BpirPLA2-I, the first ... more This paper describes a biochemical and pharmacological characterization of BpirPLA2-I, the first acidic Asp49-PLA2 isolated from Bothrops pirajai. BpirPLA2-I caused hypotension in vivo, presented phospholipolytic activity upon artificial substrates and inhibitory effects on platelet aggregation in vitro. Moreover, a synthetic peptide of BpirPLA2-I, comprising residues of the C-terminal region, reproduced the antiplatelet activity of the intact protein. A cDNA fragment of 366 bp encompassing the mature form of BpirPLA2-I was cloned by reverse transcriptase-PCR of B. pirajai venom gland total RNA. A Bayesian phylogenetic analysis indicated that BpirPLA2-I forms a clade with other acid Asp49-PLA2 enzymes from the Bothrops genus, which are characterized by the high catalytic activity associated with anticoagulant or hypotensive activity or both. Comparison of the electrostatic potential (EP) on the molecular surfaces calculated from a BpirPLA2-I homology model and from the crystallographic models of a group of close homologues revealed that the greatest number of charge inversions occurred on the face opposite to the active site entrance, particularly in the Ca2+ ion binding loop. This observation suggests a possible relationship between the basic or acid character of PLA2 enzymes and the functionality of the Ca2+ ion binding loop.
Toxicon, 2007
The ability to isolate prostate stem cells is essential to explore their role in prostate develop... more The ability to isolate prostate stem cells is essential to explore their role in prostate development and disease. In vitro prostate colonyand sphere-forming assays were used to quantitatively measure murine prostate stem/progenitor cell enrichment and self-renewal. Cell surface markers were screened for their ability to positively or negatively enrich for cells with enhanced growth potential in these assays. Immunohistochemical and FACS analyses demonstrate that specific cell surface markers can be used to discriminate prostate stromal (CD34 ؉ ), luminal epithelial (CD24 ؉ CD49f ؊ ), basal epithelial (CD24 ؉ CD49f ؉ ), hematopoietic (CD45 ؉ , Ter119 ؉ ), and endothelial (CD31 ؉ ) lineages. Sorting for cells with a CD45 ؊ CD31 ؊ Ter119 ؊ Sca-1 ؉ CD49f ؉ antigenic profile results in a 60-fold enrichment for colony-and sphere-forming cells. These cells can self-renew and expand to form spheres for many generations and can differentiate to produce prostatic tubule structures containing both basal and luminal cells in vivo. These cells also localize to the basal cell layer within the region of the gland that is proximal to the urethra, which has been identified as the prostate stem cell niche. Prostate stem cells can be isolated to a purity of up to 1 in 35 by using this antigenic profile. The remarkable similarity in cell surface profile between prostate and mammary gland stem cells suggests these markers may be conserved among epithelial stem cell populations.
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Papers by Sabrina Teixeira