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Ticks acquire nutrients only by a parasitic nature of feeding on animals, including humans. During this process, a wide array of pathogens is transmitted. Ticks of the Ixodidae family receive exactly one blood meal in each active developmental. Knowing the trophic dependence of tick metabolism on the host blood meal components may enable discovering processes essential for the tick physiology and development. Exploiting a membrane system of tick feeding and whole blood fractionation, we have revealed that adult ticks need to acquire host haemoglobin-derived haem so that they can produce viable larvae, and reproduce. Haem is not further catabolised in ticks, and iron is thus acquired via independent route with the host serum transferrin as a source molecule. Using RNA-seq, we compared transcriptome compositions between guts of blood- and serum-fed ticks. We identified fifteen gut transcripts that change their levels with respect to the presence/absence of dietary red blood cells. Glutathione S-transferase, one of the identified encoded molecules, shows a clear haeminresponsive expression at both transcript and protein levels. Its apparent haem-binding properties suggest that this protein is directly involved in haem homeostasis maintenance within the tick gut. The ultimate goal of such research is to identify and verify targets that, when blocked, would render the acquisition and/or distribution system of haem in ticks nonfunctional. This would represent a novel way of anti-tick interventions in veterinary and human medicine.

Made available in DSpace on 2016-08-10T10:38:34Z (GMT). No. of bitstreams: 1 CONSTANZA THAISE XAVIER SILVA.pdf: 856711 bytes, checksum: aa9a8d8094cd18595af6092fc0d17683 (MD5) Previous issue date: 2012-03-12 / Glaucoma refers to a group of eye diseases that gradually evolve being characterized by typical damage to the optic nerve with consequent changes in vision. The most common type is the primary open angle glaucoma (POAG) corresponding to approximately 60% of cases. The ocular epithelia expressed genes encoding the enzymes Glutathione STransferase (GST). The GST is present in various ocular structures, including aqueous humor, ciliary body, and lens. This study aimed to evaluate the genotypic profile of the gene GSTT1 and GSTM1 polymorphisms in patients with Primary Open Angle Glaucoma and control group in the city of Goiânia. Peripheral blood samples were analyzed by up to 100 samples of patients diagnosed as carriers of glaucoma, proven and 53 specimens from patients with examination within the customary standards, representing the control group. The polymorphism was assessed by PCR and analyzed in 2% agarose gel, stained with etídeo bromide. The frequencies of polymorphisms of GSTM1 and GSTT1 genes were compared with the &#967;2 test (p < 0.05%) and rate risk was assessed by the test of Odds Ratio with 95% confidence interval (&#945; = 0.05). In case it was noted that this was of genotype GSTM1 40% (n = 40) and in controls was 71.6% (n = 38). The null genotype was 60% (n = 60) and 28.3% (n = 15), respectively. The GSTT1 genotype present in case group was 52% (n = 52) and in the control group was 66% (n = 35); already the null genotype was 48% (n = 48) in case group and 34% (n = 18) in the control group. GSTM1 null genotype in the case group was more frequent than in the control group, and this difference statistically significant (p = 0. 0004). The same was not found with the GSTT1 genotype (p = 0.13). Checked also the Association of genotypes GSTM1 null/GSTT1 this the risk of glaucoma to 3.1 times more the chance of disease occurrence, suggesting that individuals who have the GSTM1 null genotype/GSTT1 this can be regarded as one of the risk factors for the development of the POAG. Already for the genotypes GSTM1 null was verified the GSTT1\/risk of 6.7 times more chance of occurrence of disease (p = 0.0004; OR: 6.7; 95% CI:-2.7 20.3), suggesting that individuals who have the GSTM1 null genotype/GSTT1 can be regarded as one of the risk factors for the development of the POAG. / O Glaucoma designa um grupo de doenças oculares que evoluem progressivamente sendo caracterizadas por danos típicos no nervo óptico com consequentes alterações de visão. O tipo mais frequente é o glaucoma primário de ângulo aberto (GPAA) que correspondente aproximadamente 60% dos casos. O epitélio ocular expressa genes que codificam as enzimas Glutationa S-Transferase (GST). A GST está presente em várias estruturas oculares, incluindo humor aquoso, corpo ciliar e cristalino. Este estudo teve como objetivo avaliar o perfil genotípico dos polimorfismos dos genes GSTM1 e GSTT1 em pacientes portadores de Glaucoma Primário de Ângulo Aberto e grupo controle na cidade de Goiânia. Foram analisadas amostras de sangue periférico de 100 amostras de pacientes comprovadamente diagnosticados como portadores de glaucoma e 53 amostras de pacientes com exame dentro dos padrões considerados normais, representando o grupo controle. O polimorfismo foi avaliado por PCR e analisados em gel de agarose a 2% e corado com brometo de etídeo. As frequências dos polimorfismos dos genes GSTM1 e GSTT1 foram comparadas com o teste &#967;2 (p<0,05%) e a taxa de risco foi avaliada pelo teste de Odds Ratio com intervalo de confiança de 95% (&#945;=0,05). No grupo caso observou-se que o genótipo GSTM1 presente foi de 40% (n=40) e nos controles foi de 71,6% (n=38). O genótipo nulo foi 60% (n=60) e 28,3% (n=15), respectivamente. O genótipo GSTT1 presente no grupo caso foi de 52% (n=52) e no grupo controle foi de 66% (n=35); já o genótipo nulo foi de 48% (n=48) no grupo caso e 34% (n=18) no grupo controle. O genótipo GSTM1 nulo no grupo caso foi mais frequente do que no grupo controle, sendo esta diferença estatisticamente significativa (p=0, 0004). O mesmo não foi encontrado com o genótipo GSTT1 (p=0,13). Foi verificado também a associação dos genótipos GSTM1 nulo/GSTT1 presente ao risco de glaucoma para 3,1 vezes mais a chance de ocorrência da doença, sugerindo que indivíduos que apresentam os genótipos GSTM1 nulo/GSTT1 presente pode ser considerado como um dos fatores de risco para o desenvolvimento do GPAA. Já para os genótipos GSTM1/GSTT1 nulos foi verificado o risco de 6,7 vezes mais a chance de ocorrência da doença (p=0,0004; OR: 6,7; IC 95%: 2,7 20,3), sugerindo que indivíduos que apresentam os genótipos GSTM1/GSTT1 nulos pode ser considerado como um dos fatores de risco para o desenvolvimento do GPAA.

As septinas constituem uma conservada família de proteínas de ligação a nucleotídeos de guanina e formação de heterofilamentos. Em mamíferos, tais proteínas estão envolvidas em uma variedade de processos celulares tais como citocinese, exocitose e tráfego de vesículas. A SEPT4 tem sido identificada em depósitos filamentosos e inclusões citoplasmáticas em Alzheimer e doença de Parkinson, respectivamente. A SEPT4 é a única proteína em associação com proteínas aberrantes em depósitos em ambos os tipos de doenças Assim, estudos adicionais de propriedades bioquímicas estruturais e funções fisiológicas para a SEPT4 podem promover importantes insights em relação ao mecanismo das doenças neurodegenerativas citadas acima. O desenovelamento térmico do domínio GTPase do SEPT4-G revelou um intermediário que agrega rapidamente na forma de fibras tipo amilóide em condições fisiológicas. Neste estudo a análise cinética da agregação do SEPT4-G foi monitorada utilizando fluorescência extrínseca e dicroísmo circular. Com os resultados e análises realizados durante este trabalho de mestrado foi possível compreender com mais detalhes a cinética de formação de agregados tipo amilóide do domínio SEPT4-G. Este trabalho também descreve a cristalização, coleta de dados, resolução e refinamento do modelo cristalográfico para a enzima Glutationa-S-Transferase de Xylella fastidiosa. Tal enzima está associada à patogenicidade da bactéria X. fastidiosa, responsável por várias doenças em plantas economicamente importantes, incluindo a Clorose Variegada dos Citros (CVC) ou Amarelinho. Algumas análises também foram realizadas após a obtenção do modelo cristalográfico demonstrando as diferenças estruturais entre GSTs bacterianas. / The septins are a conserved family of guanine nucleotides-binding and hetero-filament forming. proteins. In mammals they are involved in a variety of cellular processes, such as cytokinesis, exocytosis, and vesicle trafficking. SEPT4 has been reported to accumulate in tau-based filamentous deposits and cytoplasmic inclusions in Alzheimers and Parkinsons diseases respectively. Sept4 is unique in its association with the aberrant protein depositions in both types of diseases. Further studies on the biochemical, structural properties and physiological functions of Sept4 may therefore provide important insights into the common mechanism underlying diverse neurodegenerative disorders. Thermal unfolding of the GTPase domain of SEPT4 (SEPT4-G) revealed an unfolding intermediary which rapidly aggregates into amyloid-like fibers under physiological conditions. In this study, the kinetic analysis of aggregation of SEPT4-G was monitored using extrinsic fluorescence and circular dichroism spectroscopy. The aggregates have the ability to bind specific dyes such as Thioflavin-T (ThT), suggesting that they are amyloid in nature. Fibrils formation was monitored by the increase in ThT emission and electron microscopy as a function of temperature, pH, metal ions and protein concentration. Glutathione S-transferases (GSTs) form a group of multifunctional isoenzymes that catalyze the glutathione-dependent conjugation and reduction reactions involved in the cellular detoxification of xenobiotic and endobiotic compounds. GST from Xylella fastidiosa (XfGST) was crystallized by the vapour-diffusion method and its crystallography structure was solved for molecular replacement and refined. Afterwards, sequential and structural analyses were carried out for XfGST and others GSTs.

Tumours of the central nervous system (CNS) are the second most common cancers diagnosed in children, yet the cause of this disease remains largely unknown. This thesis examines whether polymorphisms in folate-metabolising and glutathione S transferase (GST) genes influence the risk and disease outcome of childhood CNS tumours. 204 children aged ≤18 years diagnosed with a CNS tumour at the Sydney Children??s Hospital between 1989 and 2004 were included in the study. DNA samples were isolated from archival frozen and formalin-fixed paraffin-embedded tumour tissue. Polymorphisms in GST and folate pathway genes were examined using real-time PCR. Genotype distributions in children with CNS tumours were compared to those observed in a control panel of cord blood samples from 363 healthy newborns. Children carrying at least one variant allele for each of MTHFR 677 C>T, MTHFR 1298 A>C, MTR 2756 A>G, MTRR 66 A>G, and RFC 80 G>A were found to have a 2.8-fold greater risk of developing a CNS tumour than non-carriers (OR=2.80; 95%CI: 1.08-7.56, P=0.022), an association which was even more apparent in those children with an embryonal tumour (OR=4.54; 95%CI: 1.13-15.85, P=0.016). Results also showed that children with the GSTP1 105 Val/Val genotype were three times more likely to develop a CNS tumour of embryonal cell origin than children with the GSTP1 105 Ile/Ile or Ile/Val genotypes (OR=3.02; 95%CI: 1.34-6.46, P=0.005). No such association was observed for CNS tumours of glial cell origin. The GSTM1, GSTT1, and GSTP1 Ala114Val polymorphisms did not appear to be associated with the development of a childhood CNS tumour. In addition, children with the MTHFR 677 TT or RFC 80 AA genotypes were found to have a higher risk of death within 5 years of diagnosis compared to children with one or more MTHFR 677 C or RFC 80 G alleles, respectively (HR=5.52, 95%CI: 1.00-30.37, P=0.049 and HR=5.69, 95%CI: 1.38-23.51, P=0.016, respectively), after adjusting for other prognostic factors such as sex, age at diagnosis, period of diagnosis, and tumour grade. Conversely, children with the MTR 2756 AG or GG genotypes, or MTRR 66 AG or GG genotypes, were more likely to survive compared to those with the MTR 2756 AA or MTRR 66 AA genotypes, respectively (HR=0.21, 95%CI: 0.05-0.93, P=0.040 and HR=0.11, 95%CI: 0.02-0.53, P=0.006). Results presented in this thesis indicate that polymorphisms in folate-metabolising and GST genes may play a role in the aetiology and survival of childhood CNS tumours, and that this may vary depending on the histological sub-type of tumour.

Turkish red pine is coastal tree and is a drought resistant pine that withstands more aridity and poor soils than most other timber species growing in the same climatic conditions. In Turkey, this species grows in southern and western Anatolia and is also found in the Marmara region. Drought results in a water deficit in plant tissues, which, in turn, can lead to an imbalance in the redox poise of plant cells, and thus inducing oxidative stress in plants. Resistance to conditions associated with oxidative-stress must, in part, rely on endogenous antioxidative defense mechanisms required to maintain cellular homeostasis. Glutathione is one of the major endogenous antioxidants in plants known to play an important role in plant defense mechanisms. Glutathione S-transferase (GST, EC 2.5.1.18) is a GSH dependent detoxifying enzyme in plants, which catalyzes the conjugation of GSH. In this study, we investigated the changes in cytosolic glutathione S-transferase enzyme activity using CDNB as substrate and total thiol amount in Pinus brutia Ten., related to the drought stress during four months, June to September. The osmotic pressure in the needles was also determined as an indirect measure of drought condition. Together with the increase in the temperature values from June to July, GST enzyme activity increased from 15,78 &plusmn / 1,36 &micro / moles min-1 mg protein-1 to 22,91 &plusmn / 1,99 &micro / moles min-1 mg protein-1 which was statistically significant. However in August, GST activity had fallen to 16,54 &plusmn / 1,61 &micro / moles/min/mg protein, which may be because of a local rainfall at the beginning of the August in the sampling area. In September, GST activity significantly increased with respect to June, in accordance with high temperatures. The total thiol amount was not changed significantly during the sampling period. Although there were statistically significant changes in osmotic pressure in the needdles collected during the same sampling period, it did not exactly correlated to the changes in GST activity.

Breast cancer is the most frequent malignancy among women, especially in Western societies. Highly penetrant genes such as BRCA1 and BRCA2, together with the reproductive history can constitute only 30% of the cause, so there should be other common genes, which may play a role in breast carcinogenesis according to one&#039 / s lifestyle. In our case, the effect of N-acetyl transferases (NAT1, NAT2) and glutathione-S transferases (GSTM1&amp / GSTT1) were investigated, since variations in these genes may alter their enzymatic activity and therefore their capacity to biotransform xenobiotic compounds. To evaluate the potential association between NAT1, NAT2, GSTM1 and GSTT1 genotypes and development of breast cancer, a hospital based case-control study was conducted in a Turkish study population consisting of 37 histologically confirmed incident breast cancer cases and 34 control subjects with no present or previous history of cancer. The only recognizable difference between case and control groups is the percentage of GSTM1 deletion, 67.6% and 44.1% respectively (p=0.047). The frequency of rapid NAT2 acetylator genotype is 44.4% in cases and 23.5% in controls. Especially, women with NAT2 rapid acetylator and GSTM1 null genotypes were at the elevated risk (OR, 3.8 / CI, 0.9-15.4). NAT1 rapid acetylator genotype showed no association with breast cancer. These results suggest that GSTM1 null genotype is a susceptibility factor for breast cancer, particularly in the presence of NAT2 rapid acetylator genotype.

Stroke is an important public health problem and the third leading cause of death after coronary heart diesase and all cancers in all over the world. Free radicals and oxidative stress play important role in the pathogenesis of several diseases including atherosclerosis, stroke, cancer, neurodegenerative diseases such as Alzheimer&#039 / s dementia. The activity of paraoxonase (PON1) aganist phenylacetate is known as arylesterase (ARE). Paraoxonase is an esterase associated with high-density lipoprotein (HDL) and contributes to the protective role of this lipoprotein on low-density lipoprotein (LDL) oxidation. Oxidized LDL is known to play a central role in early events in the progression of atherosclerosis which is a risk factor for stroke. Glutathione S-transferases (GSTs) catalyze the conjugation of nonpolar compounds to reduced glutathione (GSH) and detoxify toxic metabolites produced within the cell by oxidative stress to protect cells from oxidant injury. v The maximum ARE enzyme activity was detected at 10 mM Tris-HCl buffer, pH 8.0 and at 45 &deg / C. ARE enzyme was saturated with its substrate phenylacetate around 20 mM concentration. The apparent Km and Vmax values of human blood serum ARE for phenylacetate were found as 1.66 mM and 3300 nmol/min/mg, respectively. The maximum GST enzyme activity was detected at 2 mM potassium phosphate buffer, pH 5.5 and at 65 &deg / C. GST enzyme was saturated with its substrate, CDNB around 4.5 mM concentration and with its cofactor, GSH around 8 mM concentration. The apparent Km and Vmax values of human blood serum GST for CDNB substrate were found as 2.8 mM and 0.43 nmol/min/mg and for GSH were found as 4.11 mM and 0.23 nmol/min/mg, respectively. In addition, effects of three different heavy metal ions, Cd+2, Hg+2 and Ni+2, on human blood serum ARE and GST activity were studied and half maximal inhibitory concentrations (IC50) were determined. The main objective of this study was to investigate the human blood serum ARE and GST activities in patient and control groups using the optimized conditions. For this purpose, blood samples were collected from 172 ischemic stroke patients and 105 controls. Then serum obtained from blood samples were used to determine ARE and GST activities. The mean of ARE activity in patient group (n=172, 109.9 &plusmn / 32.5 U/mL ) was insignificantly lower than the mean of ARE activity in control group (n=105, 113.5 &plusmn / 33.1 U/mL, P=0.284). GST activity of the patients (10.8 &plusmn / 4.4 U/L) was insignificantly higher than that of controls (10.5 &plusmn / 4.2 U/L, P=0.483 ). In addition, statistical analysis showed hypertension, diabetes and HDL as significant risk factors of stroke.

Prostate cancer (PCa) is one of the most prevelant cancers in males in many countries, increasing in frequency with age. PCa incidence and mortality rates are not evenly distributed worldwide. Family history is an established risk factor for prostate cancer and families demonstrating autosomal dominant or X-linked transmission of susceptibility have been observed. Although an increasing number of candidate genes or hereditary prostate cancer susceptibility have been identified, only 5 to 10 percent of prostate cancer cases in the population may arise from major susceptibility genes. A few risk factors for PCa development are advanced age, an intact androgen metabolism, ethnicity, and genetic background. Other genetic factors, in combination with possible environmental risk factors for prostate cancer, may have greater public health importance. Genetic polymorphisms that may be associated with prostate cancer risk are much more common in the population than are high-penetrance cancer susceptibility genes. In this study, the effect of N-acetyltransferase 2 (NAT2) and Glutathione S-transferases (GSTM1 and GSTT1) were investigated, since polymorphism in these genes may alter their enzymatic activity and, therefore, their capacity to biotransform xenobiotic compounds. In order to evaluate the potential association between NAT2 , GSTM1 and GSTT1 genotypes and prostate cancer risk, a hospital based case control study was carried out in a Turkish population consisting of 30 histologically confirmed incident prostate cancer cases and 67 control subjects with no present or previous history of cancer. The GSTM1 and GSTT1 genotypes showed no significant differences between case and control groups, with respect to their frequencies and it was observed that GSTM1 null genotype was more common in cases with a 60% frequency. Even though the frequency of slow NAT2 acetylator genotype was 80% in cases and 50,7% in controls NAT2 rapid acetylator showed no association with prostate cancer statistically. These results suggested that GSTM1 null genotype is a susceptibility factor for prostate cancer, particularly in the presence of NAT2 slow acetylator genotype with no significance. Further studies with a larger size are required to confirm the presence and significance of this relationship.