Expressed sequence tags ( EST ) derived from the developing tilapia brain was cloned in our lab. In this study, the Neuro-2a cells was used to investigate the cell cycle ¡Vrelated gene. A stable cell line of Neuro-2a which was transfected with a cell cycel-related gene was established. The flow cytometer was used for the analysis of cell cycle. In a Neruo-2a-CIRP (cold-inducible RNA-binding protein,CIRP) stable cell line, the G2/M phase was prologate in cell cycle.

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: The effects of acute inbreeding on growth performance, yield and occurrence of deformity traits were studied in experimental full-sibling inbred populations of Mozambique tilapia Oreochromis mossambicus at three levels of inbreeding coefficients, namely F = 0.000, F = 0.250 and F = 0.375. The base population with F = 0.000 was established through the crossing of two geographically separated and genetically unrelated farm stocks. At each generation, the inbreeding depression indicated by body weight (BW), standard length (SL), specific growth rate (SGR) and yield were highly significant, but no linear relationship was found between level of inbreeding and inbreeding depression. Both condition factor (K) and the number of observed deformities appears not to be significantly affected by inbreeding at all three levels. Over all, the average inbreeding depression at F = 0.250 and F = 0.375 respectively was found to be 46.5 percent and 46.6 percent for body weight (BW); 18.2 percent and 18.0 percent for standard length (SL); 21.8 percent and 20.3 percent for specific growth rate (SGR) and 5.752 percent and 8.940 percent for flesh yield. The outbred Control group differed significantly (P<0.05) from the six inbred family groups in terms of body weight (BW), standard length (SL), specific growth rate (SGR) and yield at all levels of inbreeding studied (F = 0.000, F = 0.250 and F = 0.375). Average inbreeding depression for body weight (BW) amongst the six inbred families ranged from 39.6 to 54.2 percent at F = 0.250 (in Gen 2) and 45.6 to 47.3 percent at F = 0.375 (in Gen 3). The inbreeding depression coefficient for body weight (BW) per 10% increase in F, amongst the six inbred families, ranged from 15.9 to 21.7 percent at F = 0.250 and from 12.2 to 12.6 percent at F = 0.375. Average inbreeding depression for standard length (SL) amongst the six inbred families ranged from 14.0 to 22.3 percent at F = 0.250 and from 17.2 to 18.4 percent at F = 0.375. The inbreeding depression coefficient for standard length (SL) amongst the six inbred families ranged from 5.6 to 8.9 percent at F = 0.250 and from 4.6 to 4.9 percent at F = 0.375. Average inbreeding depression for specific growth rate (SGR) amongst the six inbred families ranged from 17.9 to 27.9 percent at F = 0.250 and from 16.7 to 27.2 percent at F = 0.375. The inbreeding depression coefficient amongst the six inbred families ranged from 7.2 to 11.2 percent at F = 0.250 and from 4.5 to 7.3 percent at F = 0.375. Average inbreeding depression for yield amongst the six inbred families ranged from 0.4 to 7.7 percent at F = 0.250 and from 8.5 to 10.2 percent at F = 0.375. The inbreeding depression coefficient for yield amongst the six inbred families ranged between 0.2 and 3.1 percent at F = 0.250 and from 2.3 to 2.7 percent at F = 0.375. The condition factor (K) of the six inbred families showed no significant differences to the Control (P > 0.05) at all levels of inbreeding with K-values ranging from 1.42 to 2.85. The occurrence of morphological deformities in all seven family groups including the Control showed no noticeable trend, with a random, nonlinear occurrence of fluctuating asymmetry observed at different inbreeding levels in O. mossambicus. This study demonstrates that inbreeding has a significant negative effect on the production traits of Oreochromis mossambicus, especially growth. Results from this study emphasize the need to create awareness amongst small scale farmers of the importance of preventing uncontrolled inbreeding in production systems, as well as to monitor inbreeding levels during the process of dissemination of improved fish strains to small scale fish growers in developing countries, including Africa. / AFRIKAANSE OPSOMMING: Die gevolge van akute inteling op die groei prestasie, opbrengs en voorkoms van misvorming eienskappe bestudeer in eksperimentele full-broer ingeteelde bevolkings van Mosambiek tilapia Oreochromis mossambicus op drie vlakke van inteling koëffisiënte, naamlik F = 0,000, F = 0,250 en F = 0,375. Die basis bevolking F = 0,000 gestig deur die kruising van twee geografies geskei en geneties onverwant plaas aandele. Op elke generasie, die inteling depressie aangedui deur die liggaam gewig (BW), standaard lengte (SL), spesifieke groeitempo (SGR) en opbrengs was hoogs betekenisvol, maar geen lineêre verband is gevind tussen vlak van inteling en inteling depressie. Beide toestand faktor (K) en die aantal waargeneem deformiteite verskyn om nie beduidend beïnvloed deur inteling op al drie vlakke. Oor alles is, die gemiddelde inteling depressie by F = 0,250 en F = 0,375 onderskeidelik gevind om 46,5 persent en 46,6 persent vir die liggaam gewig (BW) wees; 18,2 persent en 18,0 persent vir standaard lengte (SL); 21,8 persent en 20,3 persent vir spesifieke groeitempo (SGR) en 5,752 persent en 8,940 persent vir vlees opbrengs. Die outbred beheer betekenisvol verskil (P <0,05) van die ses ingeteelde familie groepe in terme van die liggaam gewig (BW), standaard lengte (SL), spesifieke groeitempo (SGR) en opbrengs op alle vlakke van inteling bestudeer (F = 0,000 , F = 0,250 en F = 0,375). Gemiddeld inteling depressie vir die liggaam gewig (BW) onder die ses ingeteelde families gewissel 39,6-54,2 persent by F = 0,250 (in Gen 2) en 45,6-47,3 persent by F = 0,375 (in Gen 3). Die inteling depressie koëffisiënt vir die liggaam gewig (BW) per 10% toename in F, onder die ses ingeteelde families, het gewissel 15,9-21,7 persent by F = 0,250 en 12,2-12,6 persent by F = 0,375. Gemiddeld inteling depressie vir standaard lengte (SL) onder die ses ingeteelde families gewissel 14,0-22,3 persent by F = 0,250 en 17,2-18,4 persent by F = 0,375. Die inteling depressie koëffisiënt vir standaard lengte (SL) onder die ses ingeteelde families gewissel 5,6-8,9 persent by F = 0,250 en 4,6-4,9 persent by F = 0,375. Gemiddeld inteling depressie vir spesifieke groeitempo (SGR) onder die ses ingeteelde families gewissel 17,9-27,9 persent by F = 0,250 en 16,7-27,2 persent by F = 0,375. Die inteling depressie koëffisiënt onder die ses ingeteelde families gewissel 7,2-11,2 persent by F = 0,250 en 4,5-7,3 persent by F = 0,375. Gemiddeld inteling depressie vir opbrengs onder die ses ingeteelde families het gewissel van 0,4-7,7 persent by F = 0,250 en 8,5-10,2 persent by F = 0,375. Die inteling depressie koëffisiënt vir opbrengs onder die ses ingeteelde families gewissel tussen 0,2 en 3,1 persent by F = 0,250 en 2,3-2,7 persent by F = 0,375. Die toestand faktor (K) van die ses ingeteelde families het geen betekenisvolle verskille op die Beheer (P> 0,05) op alle vlakke van inteling met K-waardes wissel 1,42-2,85. Die voorkoms van morfologiese afwykings in al sewe familie groepe, insluitend die beheer het geen merkbare neiging, met 'n ewekansige, nie-lineêre voorkoms van wisselende asimmetrie waargeneem op verskillende vlakke in inteling O. mossambicus. Hierdie studie toon dat inteling het 'n beduidende negatiewe uitwerking op die produksie-eienskappe van Oreochromis mossambicus, veral groei. Resultate van hierdie studie beklemtoon die noodsaaklikheid om bewustheid onder kleinboere van die belangrikheid van die voorkoming van onbeheerde inteling in die produksie stelsels, sowel as om te monitor inteling vlakke tydens die proses van verspreiding van verbeterde vis stamme klein skaal vis produsente in ontwikkelende lande te skep, insluitend Afrika.

The structure and functions of brain show sexual dimorphism in vertebrates. Brain sexual differentiation is resulted from the neural development. The neural development is determined not only by the genetic regulation, but also by the extrinsic environmental influences. Serotonin (5-hydroxytryptamine, 5-HT ) functions as a neurotransmitter or/and neuromodulator in the central nervous system. Serotonin plays a role in the neural development via serotonin receptors. The sexual differentiation of tilapia is influenced by water temperature. The lower temperature induces a higher proportion of female while the elevated temperature induces a higher proportion of male in tilapia. In the present study, the influence of temperature on the proliferation of the neurons was investigated. These results show that the proliferation of neurons are varied with the temperature. The elevated temperature influences the proliferation of neurons via central serotonin system. Serotonin 1A receptor is involved in the serotonin-induced proliferation of neuron.

In tilapia , sex determination is controled by genetic and triggered by the environmental factors. Expressed sequence tags ( EST ) derived from the developing tilapia brain is cloned in our lab. The cDNA full length of the gene, F10A83 was cloned. In the present study, F10A83 is a gene with 1526 bp of cDNA sequence, and deduced 176 amino acids of protein sequence. F10A83 was overexpressed as a GFP fusion protein in mouse neuroblastoma Neuro-2a cells. F10A83 is abundantly distributed in the nucleus of Neuro-2a cell. The protein of F10A83 was expressed in the prokaryotic cell (BL21) and eukaryotic cell (neuro-2a), and purified using a simple purification process, inducing, isolation, and Ni-NTA affinity chromatography. The protein of F10A83 in both E. coli system and neuro-2a cell line expression has been established.

Sexual differentiation is divided into gonadal sexual differentiation and brain sexual differentiation in the teleosts. Gonadal sexual differentiation is regulated by brain sexual differentiation. Brain sexual differentiation is resulted from the neural development, which lead to the sexual dimorphism of both structure and functions of brain. The neural development is influenced by the genetic factors and the external environmental factors. The lower temperature induces a higher proportion of female while the elevated temperature induces a higher proportion of male in tilapia. In addition, there is sexual difference in effects of temperature on the activity of brain neurochemicals. Water temperature plays an important role on the development of central neurotransmitter systems and sexual differentiation during the developing period. In the present study, the primary neural culture cloned from the female and male tilapia¡AOreochromis mossambicus was used. The difference of the physiological characteristics between the neural cells derived from the females and males, were investigated. These results show that the elevated temperature has an effect to enhance the proliferation in both primary neural culture of females and males.

South Africa is one of the countries with the largest mining operations in the world. Most of these mines make use of natural dams and rivers in their water supply, which often are being pumped back into the natural environment. The reticulated water pumped back into the system may contain high concentrations of dissolved chemicals, which may lead to the reduction of the endemic organisms. Many of the heavy metals mined in South Africa are highly toxic at very low concentrations, and it is therefore very important to do frequent analysis on the aquatic environment. The value of chemical analysis per se has become limiting, as chemical analysis supplies information on the levels of chemicals at a certain time, and the new trend is to incorporate biological monitoring into existing monitoring strategies. Heat shock proteins are classified as stress proteins and are primarily expressed under stressful conditions, therefore having the potential to be used as possible biomarkers. Cortisol, also a known stress hormone, has been suspected of suppressing the expression of heat shock proteins by replacing the heat shock protein on the glucocorticoid receptor. This leads to reduced levels of heat shock proteins in the organism through a negative feedback mechanism. However, before information on heat shock proteins and cortisol can be successfully incorporated into ecological risk assessment, an understanding of how cortisol influences heat shock protein levels after heavy metal exposure is needed. This study aims to determine what effect cortisol had on the production of a specific member of the Hsp70 class of heat shock proteins at different time intervals after exposure of Oreochromis mossambicus to various metals. Proteins were determination using the Bradford method, while protein separation was done using Sodium Dodecyl Sulphate-Polyacrylamide Gel Electrophoresis. Thereafter, separated proteins were subjected to Western blotting and immunoblotting in order to quantify the different Hsp70 family members in the hepatic tissue. Cortisol levels were determined using a commercially available Cortisol ELISA Test Kit. Hsp70 accumulation occurred in only two exposure groups, namely the cadmium and chromium exposure groups. Accumulation of Hsp70 demonstrated an increase in accumulation rates at the 24 hour time interval of the 10% cadmium exposure group, with accumulation remaining relatively constant in the 20% cadmium exposure group. Accumulation of Hsp70 occurred only at the 48 and 96 hour time intervals in the 10% chromium exposure group. The accumulation of Hsp76 and Hsp74 were observed to follow the same pattern throughout the 96 hour exposure. In the 10% exposure groups accumulation of both Hsp76 and Hsp74 indicated an increase in accumulation rates at the 72 hour of groups exposed to chromium and nickel, whereas the accumulation of Hsp76 and Hsp74 remains constant after exposure to cadmium. In the 20% cadmium exposure group, an increase in Hsp76 and Hsp74 accumulation was observed at the 24 hour time interval, whereby accumulation of Hsp76 and Hsp74 remains constant in both the chromium and nickel 20% exposure groups. Males accumulated higher levels of Hsp70 members than females in the cadmium and chromium exposure groups. In the 10% exposure groups the females accumulated higher levels of Hsp74, whereas the males accumulated higher levels of Hsp74 in the 20% exposure groups. Accumulation of Hsp76 proved to be higher in the females in all exposure groups, compared to the males. Cortisol concentrations remained constant throughout the 96 hour exposure period, with higher cortisol levels observed in the chromium exposure groups. Cortisol concentrations proved to increase at higher concentrations of metal exposure. Cortisol proved to have no significant effect on Hsp70 family member accumulation, except in the cadmium exposure group, where a negative regression was observed. Accumulation of the HSp70 member can be linked to possible metal specificity, due to the fact that Hsp70 accumulated in only two metal species (cadmium and chromium). However, the accumulation of Hsp76 and Hsp74 may possibly prove that the higher concentrations of specific metals leads to early accumulation of heat shock proteins. The higher accumulation levels of Hsp70 in males, compared to accumulation levels in females may be due to the greater need to discard damadged or denatured proteins, whereas higher Hsp74 and Hp76 accumulation levels in females, may be due to the higher levels of reproductive proteins present in females, compared to males. This study therefore concluded that cortisol may have no significant effect on the accumulation of the Hsp70 family members in the liver of fish. / Prof. J.H.J. Van Vuren

M.Sc. / Developments in the catchment area of the Olifants River, such as poor agricultural practices and overgrazing, caused increased amounts of erosion material to enter the river. This leads to the silting up of the Phalaborwa Barrage, situated in the river, on the border of the Kruger National Park. Because of the occasional flushing of the Barrage, in order to retain storage capacity, the Olifants River inside the Kruger National Park is subjected to very high sediment loads. This has led to poor water quality and subsequent fish mortalities. The objective of this study was therefore to investigate the possible effects of silt loads released from the Barrage on the survival of selected life stages of Oreochromis mossambicus. Silt was collected from the Phalaborwa Barrage, and the silt/fish interaction was invesigated under controlled laboratory conditions. Oreochromis mossambicus was exposed to various silt concentrations for different exposure periods to determine the LC50 and sub-lethal concentration ranges. After determination of sub-lethal values, 0. mossambicus was exposed to these concentrations to determine whether they have any effects on the oxygen consumption and selected haematological parameters of exposed fish. Lethal levels for suspended sediment are interrelated with age differences of the fish, particle size of the suspended sediment and concentration. Increased suspended sediment disrupted activity and respiratory patterns, changed orientation responses and ultimately resulted in the death of the fish. The gills and the opercular cavities of the dead fish were usually clogged with a thick layer of mucus and silt. The laboratory experiments revealed that LC5 0 values for 0. mossambicus ranged from 26,78 to 54,20g silt/1 for larvae, 35,10 to 39,20g silt/1 for juveniles and 32,93 to 35,43g silt/1 for adult fish. The larval stage was generally less tolerant of suspended silt than juveniles and adults. Sub-lethal levels for adult fish ranged from 0 to 27g silt/l, where no mortalities occurred. Exposure of adult fish to sub-lethal concentrations of silt did alter routine oxygen consumption by causing increased rates (9 to 330% from initial) of oxygen consumption. This indicates that sub-lethal levels of suspended silt concentrations result in an increase in oxygen consumption by the fish due to an increase in metabolic rate associated with increased activity and stress. Silt exposure Exposure of adult fish to sub-lethal silt concentrations (<20g silt/l) resulted in increases in haemotocrit, red blood cell counts, white blood cell counts and blood glucose concentrations, but decreases in haemoglobin and mean corpuscular volume when compared to that for the control fish. These differences became more apparent as the silt exposure concentration increased with statistically significant differences (P<0.05) between most of the selected

Contamination of aquatic ecosystems (for example, dams, lakes, rivers, streams) with heavy metals (according to McDonald and Wood (1993), the metals that are of greatest concern in fresh waters are Hg, Pb, Cd, Cu, Zn, AI, Mn and Cr (approximately in order of decreasing toxicity)) has been receiving increased worldwide attention, and the literature has many publications on the topic. These amplified levels of contamination have become a global problem in both developed and developing countries and the impact of them on aquatic environments is severe due to the inability of water to disperse contaminants. To meet this threat, ecotoxicologists face a difficult challenge on how to assess the long-term impacts of metals which have already been released into the environment and which persist in sediment, water and biota. In recent years, the field of biomarker study has evolved and expanded rapidly to address this void. Biomarkers examine molecular and biochemical responses in exposed individuals in an effort to assess the status of an impacted environment and they can also serve as a basis for a Rapid Risk Assessment of Fish Health (RRAFH) employed by water quality managers. This effort to incorporate biomarkers into RRAFH research will eventually be worthwhile. Moreover, with this multidisciplinary approach, cause-effect relationships may be examined. It was in this context that the present study evaluated three biomarkers (metallothionein (MT), Na+K+ ATPase and heat shock/stress protein 70 (HSP 70)) to determine the integrated physiological responses in Oreochromis mossambicus to one metal (copper (Cu)) at a sub lethal level over the short term (96, 48, 24, 16, 12, 6, 4 and 2 h respectively). The information gained from these tests was valuable in suggesting what the baseline levels of biomarkers in O. mossambicus would be, as studies of metabolic adjustments to stress in fish have been focused on salmonids. The demand for sensitive, specific and rapid biological assays was also addressed by the development of an HSP 70 ELISA. This assay with, with additional refinement, will also prove to be a valuable tool in the management of Cu pollution in this species. Evaluation of the biomarkers in the gills of O. mossambicus indicated that this species has relatively high levels of MT in their gills compared with other species of fish. Exposure to sub lethal Cu concentrations [Cu] caused fluctuating, but not significant, levels in Na+K+ ATPase and HSP 70 during the exposure time, and the actual [Cu] in the gill seems to be the biggest factor when interpreting results. Significant decreases were found in MT levels in the gill tissue at 2 h and 12 h of exposure. HSP 70 results also indicated non-significant decreases to Cu exposure. Data from the gills analysed in the current study suggest that down-regulation in the biomarker response might be a better indicator of Cu exposure or effect in O. mossambicus. These data also suggest that further studies should rethink the amount of Cu that the fish under investigation would find sub-lethal as this metal seems to be very well regulated in this species of fish and seems frequently to non-significantly effect the chosen biomarkers. Evaluation of the biomarkers in the liver of O. mossambicus indicated that MT levels present in the liver most likely fall within the in range of normal baselevels for tilapia living in a Cu-rich environment and that HSP 70 in the liver only responds significantly to increased aqueous [Cu] at 16 h of exposure. This study also confirms current knowledge that the toxicity assessment of any pollutant, including Cu, cannot be exclusively based on one biomarker and that the true value of these biomarkers only becomes evident when they are used not as individual indicators but as integrated responses that influence one another. All these results furnish useful data for future research into the sub lethal effects of a pollutant such as Cu. The next step would be to test the usefulness of these physiological methods for detection of similar responses in natural fish populations inhabiting Cu polluted waters. This will provide a database relating the presence of Cu to biological effects at a molecular level. / Prof. J.H.J. Van Vuuren

The principal reason for the construction of Loskop Dam was to provide irrigation water to wheat farmers settling in the Olifants River valley in the 1920s. Agriculture has since developed in the area and today, the Loskop Irrigation Board supplies water to > 700 properties with an area of 25 600 ha farming cotton, wheat, citrus and grapes near the town of Groblersdal. Serious concerns were raised about deteriorating water quality when the crocodile population began to decline and the frequency of large fish kills increased from 2006. Crocodile (Crocodylus niloticus) and Mozambique tilapia (Oreochromis mossambicus) mortalities were linked to pansteatitis which is characterised by obesity and lipid peroxidation. Known impacts on water quality include eutrophication and acid mine drainage from coal mining with associated increases of soluble metals. The aims of this study were to: i) determine whether pansteatitis could be linked to any specific parameters in the water chemistry and limnology of Loskop Dam; ii) measure concentrations of aluminium, copper, iron, manganese, selenium and zinc in various tissues of O. mossambicus to determine whether bio-accumulation was occurring and could be related to pansteatitis; iii) assess the metazoan parasite communities of O. mossambicus to determine whether they are effective indicators of ecosystem health in Loskop Dam. Four established sampling sites were used at Loskop Dam and a reference site was located at neighbouring Kranspoort Dam. Surface water quality samples were collected monthly between July and December 2010 from each site and analysed for 27 constituents including nutrients, major ions, total metals, pH and dissolved oxygen using standard methods. Orthophosphate and total inorganic nitrogen results frequently categorised Loskop Dam as eutrophic and the transitional zone of the dam was characterised by very alkaline conditions resulting from algal blooms (median pH 9.67) which increase the solubility of metals like Al. A combination of active and passive biomonitoring techniques were used for fish collection. Fish gills, brain, muscle, liver and bone were analysed for Al, Fe, Mn, Zn, Cu and Se concentrations. The most striking result was an unanticipated significant deficiency in liver Cu concentrations of fish from Loskop Dam (mean 3.4 mg kg-1) compared to fish from Kranspoort Dam (mean 62 mg kg-1). Both endo- and ectoparasites were identified and enumerated on the fish and infection rates were calculated as mean intensity (I), mean abundance (A) and prevalence (P). Fish from Loskop Dam had extremely low infection rates and two fish had no parasites whatsoever. The ratio between monoxenous and heteroxenous parasites was calculated and was very high in fish from Loskop Dam compared to fish in Kranspoort Dam and Tompi Seleka, indicating a degraded aquatic ecosystem. While no single factor was outstanding as a possible cause of pansteatitis in this study, these findings provide a good foundation from which to formulate further research questions. Copyright / Dissertation (MSc)--University of Pretoria, 2012. / Paraclinical Sciences / unrestricted

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Agradecemos a compreensão. on 2017-03-29T19:14:18Z (GMT) / Submitted by Andréia Arantes Felício null (andreia_a.felicio@hotmail.com) on 2017-03-29T19:20:52Z No. of bitstreams: 1 Tese Andréia Arantes Felício.pdf: 4621912 bytes, checksum: fcb824edfc225a271b66a12fc039e014 (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-03-29T19:24:57Z (GMT) No. of bitstreams: 1 felicio_aa_dr_sjrp.pdf: 4621912 bytes, checksum: fcb824edfc225a271b66a12fc039e014 (MD5) / Made available in DSpace on 2017-03-29T19:24:57Z (GMT). No. of bitstreams: 1 felicio_aa_dr_sjrp.pdf: 4621912 bytes, checksum: fcb824edfc225a271b66a12fc039e014 (MD5) Previous issue date: 2017-02-21 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O Brasil é o principal produtor de cana-de-açúcar do mundo e, para que esta demanda seja suprida, muitos compostos químicos são aplicados nas culturas, visando controlar o surgimento e proliferação de pragas. Assim, faz-se o uso dos praguicidas, dentre eles, o diuron (N-(3,4-diclorofenil)-N,N-dimetiluréia), que é aplicado em plantações ao redor do mundo. O diuron pode ser biodegradado em outros três principais compostos o 3,4-dicloroanilina (DCA), 3,4-diclorofenilureia (DCPMU) e 2,4-diclorofenil-N-metilureia (DCPMU). Normalmente, o diuron é aplicado nas plantações juntamente com os alquilfenóis etoxilatos (APE), como o nonilfenol etoxilato (NPE) e o octilfenol etoxilato (OPE), compostos que facilitam a dispersão do diuron. Alguns estudos têm demonstrado que tanto o diuron quanto os alquilfenóis podem causar alterações enzimáticas e/ou estrogênicas em diversos organismos. Dentre as enzimas que podem ser alteradas, estão as enzimas de biotransformação, tanto de fase I (7-etoxirresorufina-O-deetilase – EROD, 7-pentóxiresorufinaO-desalquilase – PROD, 7-benzilóxiresorufina-O-desalquilase – BROD e a P450 aromatase), quanto as de fase II (glutationa-S-transferase – GST) e as proteínas de fase III (resistência a multixenobioticos – MXR). Outros parâmetros que podem sofrer alterações são os antioxidantes (superóxido dismutase – SOD, catalase – CAT, glutationa peroxidase – GPx, glutationa redutase – GR, glutationa-6-fosfato desidrogenase – G6PDH, aldeído desidrogenase – ALDH e peroxidação lipídica), que são os responsáveis pelo controle entre a produção e o combate às espécies reativas de oxigênio (ERO). Dentre os parâmetros endócrinos que podem ser alterados, e então utilizados como biomarcadores, estão as enzimas CYP3A e a 17β-hidroxiesteróide desidrogenase (17β-HSD) e ainda a proteína vitelogenina (Vtg). Assim o objetivo deste trabalho foi avaliar, em tilápias do Nilo (Oreochromis nilotucus) (1) quais os efeitos do diuron e seus metabólitos, em associação ou não, em diferentes concentrações e (2) quais os efeitos do diuron, seus metabólitos e os alquilfenois, em associação ou não em diferentes concentrações no fígado e nas brânquias de peixes expostos por 7 dias, utilizando os seguintes parametros, EROD, BROD, PROD, GST, MXR, SOD, CAT, GPx, G6PDH e peroxidação lipídica (MDA). Em uma terceira etapa, o objetivo do trabalho foi (3) avaliar parâmetros endócrinos em tilápias mozambique (Oreochromis mossambicus) expostas ao diuron, seus metabólitos e alquilfenóis, em associação ou não, em diferentes concentrações, expostas por 7 dias, em fígado e cérebro dos peixes expostos, analisando os seguintes parâmetros: 17β-HSD, P450 aromatase, CYP3A, vitelogenina e a biotransformação do xenobiótico (in vitro). Nossos resultados demonstraram que, em tilápias do Nilo expostas a esses contaminantes nas concentrações e no tempo de exposição utilizados, todos os biomarcadores analisados sofreram alguma alteração após a exposição, alguns mais expressivos como a EROD, MDA, GPx e G6PDH e outros menos. Os resultados obtidos após a exposição de tilápias mozambique aos contaminantes também nos mostraram alterações, confirmando que esses compostos podem ser considerados desreguladores endócrinos, já que todos os parâmetros endócrinos analisados foram alterados. Assim, os resultados obtidos nos mostraram que realmente o diuron, seus metabólitos e os alquilfenóis podem causar alterações bioquímicas em tilápias do Nilo e mozambique, expostos à concentrações ambientalmente relevantes por sete dias, sendo os metabólitos e os APs os principais compostos a causar alterações nos parâmetros analisados. / Brazil is the main sugar cane producer in the world, and to support these productions many chemical compounds have being apply in agriculture, aiming to control the appearance and proliferation of pests. Therefore, the use of pesticide, as diuron, (N- (3,4-dichlorophenyl) -N,N-dimethylurea), in some crops in the world is common. Diuron can be biodegraded in three others compounds, 3,4-dichloroaniline (DCA), 3,4-dichlorophenylurea (DCPU) and 2,4-dichlorophenyl-N-methylurea (DCPMU). Normally, diuron have being applied associated with alkylphenols ethoxylates (APE), like nonilphenol (NP) and octylphenol (OP), which increase the solubility and dispersion of the herbicide. Some studies have shown that diuron and alkylphenols can cause enzymatic and/or estrogenic changes, in various organisms. Therefore, biotransformation enzymes, phase I (7-ethoxirresorufin-O-deethylase – EROD, 7- pentaxirisorufin-O-dealkylase – PROD, 7-benzyloxysorufin-O-desalkylase – BROD and P450 aromatase), phase II (glutathione-S-transferase-GST) and phase III proteins (multixenobiotic resistance – MXR), and antioxidant parameters (superoxide dismutase – SOD, catalase – CAT, glutathione peroxidase – GPx, glutathione reductase – GR, glutathione-6-phosphate dehydrogenase – G6PDH, aldehyde dehydrogenase – ALDH and lipid peroxidation), which are responsible for the control between production and degradation of reactive oxygen species (ROS). The endocrine parameters that can be altered and used as biomarkers are the CYP3A and 17β-hydroxysteroid dehydrogenase (17β-HSD) enzymes and the vitellogenin (Vtg) protein. All of these parameters can be altered after exposure of organisms to xenobiotics. Therefore, the aim of this work was evaluate the effects of (1) diuron and its metabolites, alone or in combination, in different concentrations, and the effect of (2) diuron, its metabolites and the alkyphenols, alone or in combination, in different concentration, in liver and gill of Nile tilapia (Oreochromis niloticus) exposed for 7 days, using as parameters EROD, BROP, PROD, GST, MXR, SOD, CAT, GPx, G6PDH and lipid peroxidation (MDA). In a third step, the aim of the work as (3) evaluate endocrine parameters in mossambique tilapia (Oreochromis mossambicus), exposed to diuron, its metabolites and alkyphenols, alone or in combination, in different concentrations for 7 days, in liver and brain, using as parameters 17β-HSD, CYP3A, vitellogenin and xenobiotic biotransformation (in vitro). Our results demonstrated that all contaminants, at the concentration and time of exposure, can cause alteration in all biomarkers, some more than others, as EROD, MDA, GPx and G6PDH, in Nile tilapia, and the results obtained after mozambique tilapia exposure, to the contaminants, also showed changes, confirming that these compounds can be considered endocrine disruptors. Thus, the results showed that diuron, its metabolites and alkylphenols could cause biochemical changes in fish, Nile and mossambique tilapia, exposing to the environmentally relevant concentrations for seven days, being diruon metabolites and APs the main compounds to cause changes in the analyzed parameters. / FAPESP: 2014/18825-9