Banca de QUALIFICAÇÃO: FRANCISCO RÔMULO OLIVEIRA MAGALHÃES

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : FRANCISCO RÔMULO OLIVEIRA MAGALHÃES
DATE: 25/08/2023
TIME: 09:00
LOCAL: https://meet.google.com/irk-hjbi-ijm
TITLE:

Identification of NADPH Oxidases Enzymes in Stomoxys calcitrans and Redox Activity After Different Diets 

 

KEY WORDS:

Stomoxys calcitrans; mechanical transmission; NADPH oxidase enzymes; Reactive Oxygen Species; oxidative stress; oxidative homeostasis.

PAGES: 55
BIG AREA: Ciências Biológicas
AREA: Parasitologia
SUMMARY:

̇Stomoxys calcitrans, also known as stable fly, is an arthropod widely distributed in American continent, and presents hematophagic habits mainly during the hottest time of the year. Feed behavior is persistent and aggressive, while the bite is considerably painful as no anesthetic components are present in insect saliva. For this reason, it can generate high stress conditions to cattle and horses, most affected species, causing the animals to stop feeding and resting in an attempt to defend themselves. Economic losses are even more difficult to calculate when considering that S. calcitrans acts as important vector of numerous pathogens. Despite its great importance, there are few studies on S. calcitrans physiology. In insects and other organisms, the production of reactive oxygen species (ROS) is related to events such as defense by the immune system, cell signaling and differentiation, and cell-cell recognition. In this context, NOX enzymes play important roles as their main function is to catalyze the generation of ROS, mostly superoxide, with secondary production of hydrogen peroxide, from molecular oxygen and in a NADPH-dependent way. Considering that there is a need to search for new forms of controlling the development of S. calcitrans, we believe that the knowledge about the importance of ROS and NADPH oxidases may open new doors for understanding the biology and development of these flies. These molecules could serve as new target for the generation of more specific pesticides, with less damage to other species and the environment. In this work, we intend to investigate the function of NOX enzymes and ROS production in S. calcitrans and their role and its immune defense against parasitic protozoa. We will analyze the role of these enzymes in the generation of ROS  and how this modulation, signaling and control of reduction-oxidation (redox) affects the biology of these insects. Results obtained by in silico query at NCBI database led to the identification of a group of five open reading frames (ORFs) in S. calcitrans annotated as hypothetical proteins. Our analysis showed that these ORFs present identity of about 70% and 98% with NOX 5 and DUOX1/2 enzyme sequences from Drosophila melanogaster and Musca domestica, respectively. Through quantitative qPCR we detected the expression of two different isoforms of NADPH oxidases in three segments of S. calcitrans: fatty body and intestine. We observed the production of superoxide (O2 ̇ˉ) and hydrogen peroxide (H2O2) in different fly tissues and specific conditions, producing a higher generation of ROSs in blood-fed flies. Our initial data provide a new insight into the production of ROS in the gut and fatty body of S. calcitrans, highlighting their relation to NOX activity, with possible implications for a better understanding of the molecular mechanisms that influence its redox regulation, immune system, metabolism, and vector competence. In the future, new experiments will be carried out in order to better understand the physiological mechanisms of S. calcitrans.

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COMMITTEE MEMBERS:
Presidente - 1792175 - PATRICIA FAMPA NEGREIROS LIMA
Interna - 3103528 - CLAUDIA BEZERRA DA SILVA
Interna - 1545840 - LUCIA HELENA PINTO DA SILVA
Externo ao Programa - 1555317 - EMERSON GUEDES PONTES - UFRRJ