Stuttgart, Universiẗat, Diss., 2001.

<p>Rezultati prikazani u ovom radu opisuju efekte in vivo primene atrazina (2-hloro-4-<br />etilamino-6-izopropilamino-s-triazin) na ex vivo steroidogenezu u Leydig-ovim ćelijama<br />peripubertalnih pacova (tretiranih sa 50 mg/kg i 200 mg/kg telesne mase od 23. do 50.<br />dana starosti). Dobijeni rezultati jasno ukazuju da 28-dnevna in vivo primena atrazina<br />snažno inhibira testikularnu steroidogenezu, smanjujući ekspresiju gena za steroidogene<br />enzime i druge regulatorne proteine uključene u kontrolu testikularne steroidogeneze u<br />Leydig-ovim ćelijama peripubertalnih pacova. Rezultati in vivo primene atrazina<br />pokazuju da atrazin snažno inhibira ekspresiju gena za luteinizirajući hormon receptor<br />(LHR), skevendžer receptor-B1 (SR-B1), steroidogeni faktor-1 (SF-1), steroidogeni<br />akutni regulatorni protein (StAR), translokator protein (TSPO), fosfodiesterazu 4B,<br />3&beta;&minus;hidroksisteroid dehidrogenazu (&Eta;SD), CYP17A1 i 17&beta;HSD. Rezultati u okviru ovih<br />istraživanja pokazuju da primena atrazina tokom prepubertalnog perioda razvoja mužjaka<br />pacova dovodi do dozno-zavisnog smanjenja nivoa cAMP i snažne inhibicije androgeneze<br />u prisustvu hCG. Obzirom na blokadu ekspresije LHR, prvog elementa u aktivaciji<br />cAMP-signalnog puta, moglo bi se predpostaviti da je to uzrok blokade androgeneze kod<br />atrazinom-tretiranih životinja. Takođe, rezultati ukazuju na inhibiciju supstrat-stimulisane<br />produkcije androgena paralelno sa redukcijom ekspresije steroidogenih enzima CYP17A1<br />i 17&beta;HSD. U drugom delu ove doktorske disertacije, ispitivan je efekat direktne in vitro<br />primene različitih doza atrazina (1 nM, 1 &mu;M, 20 &mu;M, 50 &mu;M) na ekspresiju i aktivnost<br />steroidogenih enzima u kulturi preči&scaron;ćenih Leydig-ovih ćelija testisa peripubertalnih<br />pacova, pri čemu je zabeleženo stimulatorno dejstvo pomenutog herbicida. Naime,<br />zabeleženo je povećanje bazalne i hCG-stimulisane produkcije testosterona praćeno<br />povećanim nivoom cAMP u medijumu tretiranih ćelija. Pri ispitivanju ekspresije gena za<br />steroidogene enzime i regulatorne proteine, zabeleženo je povećanje ekspresije gena za<br />SF-1, StAR, CYP17A1 i 17&beta;HSD u hCG-stimulisanim uslovima. Takođe, povećana je i<br />produkcija testosterona nakon dodavanja progesterona i androstendiona kao supstrata,<br />kod Leydig-ovih ćelija tretiranih sa atrazinom. Da bi poku&scaron;ali da objasnimo za&scaron;to postoje<br />razlike u efektu atrazina u zavisnosti od načina primene, postavili smo jednokratni in vivo<br />eksperiment sa atrazinom (tretman sa 50 mg/kg i 200 mg/kg telesne mase, životinje<br />tretirane 50. dana starosti). Rezultati ovih eksperimenata ukazali su na up-regulaciju<br />testikularne steroidogeneze, kao i na povećan nivo cAMP kod životinja tretiranih sa<br />atrazinom Stoga, nivo cAMP se pojavljuje kao karika koja povezuje sva tri kori&scaron;ćena<br />eksperimentalna pristupa. Međutim, ostaje otvoreno pitanje na koji način atrazin utiče na<br />modulaciju nivoa cAMP i to pitanje predstavlja motiv za dalja istraživanja. Sumarno,<br />dobijeni rezultati ukazuju da 24-časovni tretman atrazinom izaziva povećanje, a<br />prolongirani tretman snažno smanjenje steroidogenog kapaciteta Leydig-ovih ćelija<br />peripubertalnih pacova.</p> / <p> In the present study, we investigated the effects of oral dosing of atrazine (2-chloro-4-<br /> ethylamino-6-isopropylamino-s-triazine) to peripubertal male rats (50 mg/kg and 200<br /> mg/kg body weight daily from postnatal day 23 to 50) on ex vivo Leydig cell<br /> steroidogenesis. Leydig cells from treated rats were characterised by significant decline in<br /> mRNA transcripts of several genes responsible for steroidogenesis: luteinizing hormone<br /> receptor (LHR), scavenger receptor-B1, steroidogenic acute regulatory protein (StAR),<br /> translocator protein, steroidogenic factor-1 (SF-1), phosphodiesterase 4B,<br /> 3&beta;&minus;hydroxysteroid dehydrogenase (&Eta;SD), CYP17A1 and 17&beta;HSD. In the presence of<br /> human chorion gonadotropin, the dose-dependent decrease in extra cellular cAMP level<br /> and accordingly strong inhibition of androgenesis were obtained. The transcription of<br /> LHR gene in Leydig cells of atrazine-treated rats was down-regulated in a dose-dependent<br /> manner, which could be the reason for reduction in cAMP level and expression of cAMPdependent<br /> genes. The results also indicated inhibition of substrate-stimulated androgen<br /> production in parallel with reduced expression of steroidogenih enzymes CYP17A1 and<br /> 17&beta;HSD. In the second part of this study we examined direct 24 h in vitro effect of<br /> different doses of atrazine (1 nM, 1 &mu;M, 20 &mu;M, 50 &mu;M) on expression and activity of<br /> steroidogenic enzymes in purified Leydig cells obtained from peripubertal rats. Obtained<br /> results indicated that 24 h-incubation of peripubertal Leydig cells in the presence of<br /> atrazine increased steroidogenic capacity of that cells. Increased basal and hCGstimulated<br /> testosterone production were accompanied by increasing levels of cAMP in the<br /> medium of treated cells. Also, in comparison to controls, gene expression revealed<br /> increased expression of SF-1, StAR, CYP17A1 and 17&beta;-HSD. When Leydig cells were<br /> challenged with progesterone and &Delta;4&ndash;androstenedione, testosterone production was<br /> increased in atrazine chalenged Leydig cells. To address these two opposite effects of<br /> atrazine we performed 24 h in vivo experiment in which peripubertal male rats (on<br /> postnatal day 50) were exposed to single atrazine treatment (50 mg/kg- and 200 mg/kgbody<br /> weight by gavage), and 24 h later, Leydig cells were isolated and testosterone levels<br /> in medium determined in basal and in hCG-stimulated conditions after 2 h-incubation<br /> period. Obtained results indicated that single in vivo exposure to atrazine was also<br /> accompanied 24 h later by up-regulation of Leydig cell androgenesis and increased cAMP<br /> level. According to the results obtained in this study, it seems that modulation of cAMP<br /> levels appear as a link that connects all three experimental approaches. However, the<br /> question of how atrazine affects the modulation of cAMP levels remains open, and<br /> present a motive for further research. In concluson, obtained results indicated that 24 h<br /> treatment with atrazine caused an increase, while prolonged treatment strongly reduce<br /> steroidogenic capacity of peripubertal Leydig cells.</p>

Submitted by ALESSANDRO NASCIMENTO null (nascimentoagro@gmail.com) on 2016-02-19T00:00:45Z No. of bitstreams: 1 DISSERTAÇÃO-Alessandro-Nascimento (2).pdf: 3665458 bytes, checksum: adf59a9631348439451f395c70313d51 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-02-19T18:18:38Z (GMT) No. of bitstreams: 1 nascimento_a_me_ilha.pdf: 3665458 bytes, checksum: adf59a9631348439451f395c70313d51 (MD5) / Made available in DSpace on 2016-02-19T18:18:38Z (GMT). No. of bitstreams: 1 nascimento_a_me_ilha.pdf: 3665458 bytes, checksum: adf59a9631348439451f395c70313d51 (MD5) Previous issue date: 2016-02-04 / Para o controle eficaz de plantas daninhas na cultura da cana-de-açúcar é pouco provável que uma única aplicação de herbicida em pré-plantio incorporado seja suficiente para manter a cultura no limpo até o seu fechamento. O objetivo do trabalho foi averiguar a eficácia (ou ineficácia) de herbicidas aplicados uma única vez em pré-plantio-incorporado para o controle de plantas daninhas em cana-de-açúcar. O delineamento experimental utilizado foi o de blocos ao acaso, com oito tratamentos e quatro repetições com parcelas de 30 m2. A eficiência dos herbicidas no controle das plantas daninhas foi avaliada aos 30, 60, 90, 120 e 150 dias após a aplicação (DAA), por meio de uma escala visual, onde 0% = nenhum controle e 100% = controle total das plantas daninhas, considerando-se como eficiente o controle igual ou superior a 80%. Concluiu-se que todos os tratamentos (s-metolachlor a 1,5 e 3,0 L p.c./ha; s-metolachlor+atrazin a 1,5 e 3,0 + 3,0 L p.c./ha; trifluralin a 2,0 L p.c./ha e trifluralin+atrazin a 2,0 + 3,0 L p.c./ha) foram altamente seletivos para a cultura da cana-de-açúcar, variedade RB 86-5453 e foram ineficazes para as dicotiledôneas Calopogonium muconoides (aos 150 DAA) e Amaranthus deflexus (aos 120 DAA) e, os tratamentos s-metolachlor+atrazin (1,5 e 3,0 + 3,0 L p.c./ha) e trifluralin+atrazin (2,0 + 3,0 L p.c./ha) foram eficientes para a espécie Panicum maximum. Todos os tratamentos proporcionaram menor crescimento e produtividade da cana-de-açúcar em relação à testemunha no limpo. Entre as testemunhas observou-se reduções no crescimento e principalmente na produtividade (55%) da testemunha sem capina em relação à capinada. Uma única aplicação dos herbicidas trifluralin, s-metolachlor, atrazin e suas combinações em pré-plantio incorporado, não foram suficientes para manter a cultura de cana-de-açúcar livre de mato-competição até o seu fechamento, indicando a necessidade de outros métodos de controle subsequentes. / To the weeds control in the sugarcane is unlikely that a single application of herbicide in pre-planting-incorporated is sufficient to maintain the culture in clean until its closing. The objective of the work was to determine the effectiveness (or ineffectiveness) of herbicides applied only once in pre-plant-incorporated for weed control in sugar cane. The experimental design was a randomized block with eight treatments and four replications with plots of 30 m2. The herbicides efficiency in weed control was assessed at 30, 60, 90, 120 and 150 days after application, through a visual scale, where 0% = no control and 100% = full control of plants weeds, considering how efficient control than or equal to 80%.It was concluded that all treatments (1.5 and 3.0 Lc.p./ha of s-metolachlor; 1.5 and 3.0 L + 3.0 Lc.p./ha of s-metolachlor+atrazin; 2.0 Lc.p./ha of trifluralin and 2.0+3.0 Lc.p./ha of trifluralin+atrazin) were highly selective for the culture of sugar cane, variety RB 86-5453 and were ineffective for the dicotyledons Calopogonium muconoides (at 150 DAA) and Amaranthus deflexus (at 120 DAA) and, the treatments s-metolachlor + atrazin (1.5 and 3.0 + 3.0 Lc.p./ha) and trifluralin + atrazin (2.0 L + 3.0 c.p./ha) were effective for the species Panicum maximum. All treatments showed lower growth and yield compared to the control in the clean. Among the controls was observed reductions in growth and 55% reduction in the productivity of the treatment without controlling weeds in relation to treatment weeded. A single application of trifluralin herbicides, s-metolachlor, atrazine and their combinations in corporate pre-planting, were not enough to keep the culture of sugarcane free of weed competition until its closure, indicating a need for other methods subsequent control.

The evaluation of the sub-chronic exposure to atrazine on crayfish The aim of this study is to evaluate the sub-chronic effect of atrazin on a behaviour, oxidative stress, antioxidant enzyme aktivities and biochemical profile of haemolymph in. These complex data should help to appraise the impact of this substance in the environment. The total test duration was 28 days and was divided into two periods. The first 14 days the crayfish were exposed to two concentrations of atrazine: 6.86 micrograms per liter (ATRenv = environmental concentration in the water in the Czech Republic) and 1.21 milligrams per liter (ATR10% = is coincident to 10% LC50). After the atrazine treatments the depuration 2 weeks phases in water without any chemicals followed. The results indicate that sub-chronic effect of atrazine influenced neither the behaviour of the crayfish nor the level of oxidative stress (measured by TBARS), whereas the changes of superoxiddismutase (SOD) were observed in all tissues (muscles, gills and hepatopancreas). The changes of enzyme activity were observed in catalase (CAT; hepatopancreas and the muscle tissue), glutathione S-transferase (hepatopancreas and the gills tissue), glutathione reductase (GR; the hepatopancreas tissue) and reduced glutathione (the muscle tissue). The influence of ATRenv on the biochemical profile of haemolymph at the following parameters was estimated only for lactate and alkaline, however phosphatase changes made by ATR10% were significant for glucose, ammonia, lactate and alkaline phosphatase measurements. The sub-chronical effect changed the activity of all antioxidant enzymes in hepatopancreas, muscles and the gills tissue of the observed crayfish. The presented results in this study are giving compact information of impact of atrazine on the crayfish and the whole water environment. The suggestion of using the crayfish for tests of toxicity looks like an ideal supplement for triazine herbicide estimations.