Repositório RCAAP

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

CHAPTER 2: The aquatic environment is contaminated by toxic chemicals from industrial, agricultural and domestic activities. The environmental toxicology characterizes the effects related by chemical substances present in some species and their biological implications. The genus Rhamdia presents B chromosomes, which appear to be conserved in most species of the genus, and represents character important to the evolutionary process. The study aimed to evaluate the cytogenetic aspects of 45 copies of a population of Rhamdia quelen collected in three areas with different standards of water quality in Uberabinha River, the region of Uberlandia, Minas Gerais. The species were evaluated by the Micronucleus Test, by counting the erythrocytes. The TMN results indicate the significant genotoxic and cytotoxic potential in the points, in agreement with chemical analysis. This way the species Rhamdia quelen can be considered an efficient bioindicator. The chromosome counting showed the modal number 2n=58 with variance between none and one to seven B chromosomes. The higher frequence of B chromosomes and presence of the karyotype with seven chromosomes supernumerary occurred at Point 3, referring to the Local with the highest potentially mutagenic. There was positive correlation between the presence of B chromosomes and the interference on Environmental quality.

Universidade Federal de Uberlândia

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

In bees, juvenile hormone (JH) is a important factor in determining castes and also has a role in age polyethism. The first steps in the synthesis of JH are known as mevalonate pathway. In this pathway are present, among others, the 3-hydroxy-3- methylglutaryl-CoA reductase (HMGR) and farnesoic acid O-methyltransferase (FAMeT) enzymes. Thereafter, in insects occur successive reactions that culminate in JH-III production, in which the last reaction is catalyzed by the methylfarnesoate epoxidase (MFE). There is evidence that JH production is related both to the expression profile of these enzymes - in terms of mRNA production - and enzymatic activities. In this study, we analyzed the hmgr and mfe genes in different tissues, stages and castes of Melipona scutellaris. We also analyzed famet gene in larvae and adults of this species. Our results indicate that HMGR and MFE enzymes, in M. scutellaris, are probably involved in the synthesis of JH. Moreover, the MFE is a candidate for the rate limiting enzyme of this pathway. The FAMeT enzyme shows no evidence of relation to the synthesis of JH. Our results also suggest an inter-regulation between JH and ecdysteroids in M. scutellaris.

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

A novel DNA electrochemical biosensor to detection of bacterial meningitis, a worldwide endemic human disease, was investigated and is reported in this paper. This device is based in the use as molecular probe of specific DNA fragments of the genome of the bacteria Neisseria meningitidis, incorporated onto graphite electrode modified with poly(4-aminophenol). In this device, the presence of a complementary specific DNA sequence was evaluated monitoring the DNA hybridization reaction by differential pulse voltammetry, using an electroactive intercalator ethidium bromide as hybridization indicator. The proposed DNA biosensor showed that complementary oligonucleotide (NM2) could be quantified with a low detection limit (1.4 × 10 -10 mol.L-1, S/N=3) and good linearity (R=0.995). In addition, the biosensor showed high selectivity, discriminating non-specific targets and retaining more than 90% of its original activity, after 120 days of storage.

Conselho Nacional de Desenvolvimento Científico e Tecnológico

The venom of snakes from genus Bothrops contain toxin composed of several pharmacologically active substances, especially protein constituents, which act to induce local and systemic physiological changes in the body in which it is inoculated. Among the enzymatic component of the venoms are metalloproteinases, which are proteolytic enzymes zinc-dependents involved in the effects of ofidic envenoming. BmooMPα-I is a fibrin(ogen)olytic non-hemorrhagic enzyme isolated from B. moojeni snake venom. It shows a molecular mass of about 24.5 kDa, and belongs to the P-I class. In order to investigate its activity in relation to physiological processes, this work had as objective evaluated the BmooMPα-I influence in platelet aggregation and in inflammatory angiogenesis. The enzyme inhibited specifically the epinephrine-induced platelet aggregation when previously incubated with platelet rich plasma, not showing inhibition with ADP, collagen and ristocetin. Its activity is suppressed by denaturation, showing the dependence of the enzymatic action in the inhibition mechanism. About the inflammatory angiogenesis, our results showed that BmooMPα-I is an angiogenesis inhibitor.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

The intake of energy excess and sedentary lifestyle are conditions associated with the development of obesity and resistance to insulin action. The origin of this resistance is tentatively explained by several theories, which include the theory of membrane resistance, whereby an excessive content of cholesterol would be a determinant of changes in the behavior of this cellular barrier, particularly in the transduction of hormonal signals. These changes in the membrane behavior would result from the excess supply of cholesterol and would occur in all cells of the human organism, with the greatest impact on myocytes, which are responsible for a significant consumption of glucose from the blood. The composition and behavior of the erythrocyte membrane is also influenced blood levels of cholesterol and glucose, such that these cells constitute a minimally invasive model to study the behavior of membranes in situations of energy homeostasis break, as occurs in obesity. The osmotic stability of the erythrocyte represents a representative property of the behavior of the cell membrane. It can be conveniently studied by analyzing the sigmoidal curve of the dependence of light absorbance of hemoglobin released in the lysis produced by a hypotonicity gradient. This curve can be adjusted to the Boltzmann equation, with determination of the salt concentration in the point of half transition (H50) and the variation in the concentration of salt required to promote the lysis transition (dX). The variables H50 and dX present inverse and direct relationships, respectively, with the osmotic stability of erythrocytes. The reason dX/H50 is a combined variable that presents a direct relation with the stability of erythrocyte membrane. In this study, the stability of erythrocytes was assessed before and after an activity program that included nutritional and psychological counseling, as well as four weekly sessions of aerobic and resistance exercises, lasting 30 minutes each session, for five months, in a population consisting of 44 adolescents (16 males and 28 females). To understand the interrelationships of the behavior of erythrocytes with variables subject to change during the training program established, were also evaluated anthropometric, hematological, biochemical, hormonal, and some biomarkers of organs and tissues integrity. The study ended with 21 adolescents (8 males and 13 females). At the end of the program of training, there was a decrease in all anthropometric variables considered (body mass, body mass index, waist circumference and fat content); an increase of some of the hematological variables [hemoglobin (Hb), hematocrit (Ht), mean corpuscular volume (MCV) and distribution width of red blood cells (RDW)]; a reduction in blood lipids (total cholesterol, VLDL-C and triglycerides); elevation in the blood levels of creatinine and sodium and decrease in the potassium levels; elevation in the blood concentrations of total and direct bilirubin and decreased activity of γ-glutamyl transferase (γGT); decreased levels of thyroid stimulating hormone (TSH) and elevated levels of free thyroxine (FT4) and follicle- stimulating hormone (FSH); and increased stability of erythrocytes. A cross-sectional treatment of the correlations between the variables of stability and each of the variables analyzed in the study showed that: 1) the values of H50 increased with increase in hemoglobin, mean corpuscular hemoglobin (MCH), mean corpuscular volume (MCV), sodium and luteinizing hormone (LH) and decreased with increasing levels of glycated hemoglobin (Hb1C); 2) the values of dX decreased with increase in RBC, Hb, MCH, MCHC, VLDL-C, Tg, urea, creatinine, potassium and cortisol, and increased with increase in RDW; 3) the values of dX/H50 maintained the same pattern of dX correlations, except for urea and creatinine levels. These results suggest that the increased stability of erythrocytes after the training program was driven by an increase in RDW, since this was the only parameter that showed a direct relationship with dX/H50, and perhaps by decreasing levels of Hb1C, which was the only parameter that showed an inverse relationship with H50, although the decline in Hb1C after the training program was not statistically significant.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais