Biomedical subjects

Helena Carla Castro

Publications and source records attributed to Helena Carla Castro.

5 recordsLinked to original sources

PubMed2006

Structure-function inferences based on molecular modeling, sequence-based methods and biological data analysis of snake venom lectins.

Lectins are a structurally and functionally diverse group of proteins from different sources, capable to recognize and bind specifically carbohydrates. Several snake venoms contain calcium-dependent true lectins (SVLs) that recognize galactose. Herein, in order to enlighten some of the structure-function relationships of snake venom lectins (SVLs), we constructed theoretical models for 10 SVLs based on the Crotalus atrox lectin (CaL), the only SVL crystal structure available, and compared with other animal and plant lectins, and C-type lectin-like proteins (CLPs) that do not bind carbohydrates. Although these are theoretical structures, we could identify some SVL features, including: (i) a singular intrachain disulfide bond (Cys(38)-Cys(133)) that is not present in CLPs; (ii) a significant reorientation (39-41A) of the 80's loop position that folds back to the globular domain, assists the carbohydrate recognition domain (CRD), and orients the dimer formation, even in BfL-1 and BfL-2, which did not present the Cys(86) interchain; (iii) a CRD presenting a negative and concave surface that allows the interaction with the specific saccharide hydroxyl groups and calcium ion; (iv) the role of water molecules in some interchain interactions, similar to other animal and plant lectins; and (v) the inability of forming oligomers in contrast to CaL and some CLPs, such as convulxin.

Amino Acid Sequence↗

PubMed2006

Design, synthesis, SAR, and biological evaluation of new 4-(phenylamino)thieno[2,3-b]pyridine derivatives.

In this work, we performed the design, synthesis, and the structure-activity relationship studies of 13 new derivatives of thieno[2,3-b]pyridine. These derivatives were prepared in high yields (96-70%) and their structures were elucidated by IR, (1)H, (13)C NMR, and MS. The biological results showed some derivatives as antiparasitic agents against Giardia lamblia. Computational analysis of HOMO and LUMO energy, HOMO orbital coefficient distribution, electrostatic potential map, dipole moment, and density HOMO was performed to gain insight into the SAR aspects. This study pointed the p-methoxy substituted derivative as a leading compound for the development of new microbicidal medicines based on thieno[2,3-b]pyridine analogs.

Aminopyridines↗

PubMed2005

Snake Venom: Any Clue for Antibiotics and CAM?

Lately several naturally occurring peptides presenting antimicrobial activity have been described in the literature. However, snake venoms, which are an enormous source of peptides, have not been fully explored for searching such molecules. The aim of this work is to review the basis of antimicrobial mechanisms revealing snake venom as a feasible source for searching an antibiotic prototype. Therefore, it includes (i) a description of the constituents of the snake venoms involved in their main biological effects during the envenomation process; (ii) examples of snake venom molecules of commercial use; (iii) mechanisms of action of known antibiotics; and (iv) how the microorganisms can be resistant to antibiotics. This review also shows that snake venoms are not totally unexplored sources for antibiotics and complementary and alternative medicine (CAM).

Journal Article↗

PubMed2004

Role of the undergraduate student research assistant in the new millennium.

In this study, we analyze the contribution of the undergraduate student who participates in the process of generating scientific data and developing a research project using Brazilian research as an example. Historically, undergraduate students have performed the critical role of research assistants in developing countries. This aspect has been underappreciated as a means of generating scientific data in Brazilian research facilities. Brazilian educational institutions are facing major age-related generational changes among the science faculty within the next 5-10 yr. A lack of adequate support for graduate students leads to a concern that undergraduates will not be interested in choosing research assistant programs and, subsequently, academic research careers. To remedy this situation it is important to focus on ways to encourage new research careers and enhance university-industry collaborations.

Animals↗

PubMedDate not supplied

Infection of mouse dermal fibroblasts by the monoxenous trypanosomatid protozoa Crithidia deanei and Herpetomonas roitmani.

Traditionally, monoxenous trypanosomatid protozoa are not believed to infect vertebrate cells. Using light and electron microscopy, we show that the monoxenous trypanosomatids Crithidia deanei and Herpetomonas roitmani are able to infect dermal mouse fibroblasts in vitro. We present experimental evidence of phagocytosis of these trypanosomatids, and demonstrate their survival in vertebrate cells. This paper raises the question about the role of C. deanei and H. roitmani, and perhaps other monoxenous trypanosomatid species, in opportunistic infections of immunocompromised individuals and cutaneos lesions in vertebrate hosts.

Animals↗