RESUMO
AIMS: This study aimed to evaluate new d-xylose-fermenting yeasts from Brazilian ecosystems for the production of second-generation ethanol. METHODS AND RESULTS: d-xylose-fermenting yeasts isolated from rotting wood and wood-boring insects were identified as the species Scheffersomyces parashehatae, Scheffersomyces illinoinensis, Spathaspora arborariae and Wickerhamomyces rabaulensis. Among the yeasts tested, those of Sc. parashehatae exhibited the highest ethanol production when cultivated on complex medium (Yp/set = 0·437 g g-1 ). Sheffersomyces illinoinensis and Sp. arborariae showed similar ethanol production in this assay (Yp/set up to 0·295 g g-1 ). In contrast, in sugarcane bagasse hemicellulosic hydrolysate, Sc. parashehatae and Sc. illinoinensis exhibited similar ethanol production (Yp/set up to 0·254 g g-1 ), whereas Sp. arborariae showed the lowest results (peak Yp/set = 0·160 g g-1 ). Wickerhamomyces rabaulensis exhibited a remarkable xylitol production (Yp/sxyl = 0·681 g g-1 ), but producing low levels of ethanol (Yp/set = 0·042 g g-1 ). CONCLUSIONS: The novel d-xylose-fermenting yeasts showed promising metabolic characteristics for use in fermentation processes for second-generation ethanol production, highlighting the importance of bioprospecting research of micro-organisms for biotechnological applications. SIGNIFICANCE AND IMPACT OF THE STUDY: This study widens the scope for future researches that may examine the native yeasts presented, as limited studies have investigated these species previously.
Assuntos
Celulose/metabolismo , Etanol/metabolismo , Polissacarídeos/metabolismo , Saccharomycetales/metabolismo , Saccharum/metabolismo , Madeira/microbiologia , Brasil , Ecossistema , Fermentação , Saccharomycetales/classificação , Saccharomycetales/genética , Saccharomycetales/isolamento & purificação , Xilitol/biossíntese , Xilose/metabolismoRESUMO
Cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) molecule is expressed on T-lymphocyte membrane and negatively influences the antigen-presenting process. Reduced expression of CTLA-4 due to gene polymorphisms is associated with increased risk of autoimmune disorders, whose physiopathology is similar to that of post-transfusion red blood cell (RBC) alloimmunization. Our goal was to evaluate if polymorphisms of CTLA-4 gene that affect protein expression are associated with RBC alloimmunization. This was a case-control study in which 134 sickle cell disease (SCD) patients and 253 non-SCD patients were included. All patients were genotyped for the polymorphisms 49A/G and -318C/T of CTLA-4 gene. The genotype frequency of -318C/T differed significantly between alloimmunized and nonalloimmunized SCD patients, irrespective of clinical confounders (p = .016). SCD patients heterozygous for -318T allele presented higher risk of alloantibody development (OR: 5.4, CI: 1.15-25.6). In conclusion, the polymorphism -318C/T of CTLA-4 gene is associated with RBC alloimmunization among SCD patients. This highlights the role played by CTLA-4 on post-transfusion alloantibody development.
Assuntos
Anemia Falciforme/genética , Doenças Autoimunes/genética , Antígeno CTLA-4/genética , Eritrócitos/imunologia , Adulto , Anemia Falciforme/sangue , Anemia Falciforme/imunologia , Anemia Falciforme/prevenção & controle , Células Apresentadoras de Antígenos/imunologia , Células Apresentadoras de Antígenos/patologia , Doenças Autoimunes/sangue , Doenças Autoimunes/imunologia , Doenças Autoimunes/patologia , Antígeno CTLA-4/imunologia , Eritrócitos/patologia , Feminino , Predisposição Genética para Doença , Genótipo , Humanos , Imunização/efeitos adversos , Isoanticorpos/imunologia , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único/genética , Fatores de Risco , Linfócitos T/imunologia , Linfócitos T/patologiaRESUMO
Severe acute pancreatitis remains a life-threatening condition, responsible for many disorders of homeostasis and organ dysfunction. By means of a mnemonic 'PANCREAS', eight important steps in the management of severe acute pancreatitis are highlighted. These steps follow the principle of goal-directed therapy and should be borne in mind after diagnosis and during clinical treatment. The first step is perfusion: the goal is to reach a central venous pressure of 12-15mmHg, urinary output 0.5-1ml/kg/hour and inferior vena cava collapse index greater than 48%. Next is analgesia: multimodal, systemic and combined pharmacological agent and epidural block are possibilities. Third is nutrition: precocity, enteral feeding in gastric or post-pyloric position. Parenteral nutrition works best in difficult cases to achieve the individual total caloric value. Fourth is clinical: mild, moderate or severe pancreatitis according to the Atlanta criteria. Radiology is fifth: abdominal computed tomography on the fourth day for prognosis or to modify management. Endoscopy is sixth: endoscopic retrograde cholangiopancreatography (cholangitis, unpredicted clinical course and ascending jaundice); management of pancreatic fluid collection and 'walled-off necrosis'. Antibiotics come next: infectious complications are common causes of morbidity. The only rational indication for antibiotics is documented pancreatic infection. The last step is surgery: the dogma is represented by the 'three Ds' (delay, drain, debride). The preferred method is a minimally invasive step-up approach, which allows for gradually more invasive procedures when the previous treatment fails.
Assuntos
Pancreatite Necrosante Aguda , Colangiopancreatografia Retrógrada Endoscópica , Nutrição Enteral , Humanos , Pancreatite Necrosante Aguda/diagnóstico por imagem , Pancreatite Necrosante Aguda/terapia , Guias de Prática Clínica como Assunto , Prognóstico , Tomografia Computadorizada por Raios XRESUMO
Age is a key factor in the development of prostatic lesions. An increase in reactive oxygen species levels occurs during aging. Furthermore, the indiscriminate use of anabolic androgenic steroids and physical exercise alter the availability of hormones and may promote the appearance of lesions. This study examined whether the use of nandrolone decanoate (ND), associated or not with resistance exercise training, affects the pathways related to the inflammatory response in the ventral prostate of adult and aged rats. Sprague-Dawley rats were distributed into eight experimental groups: sedentary with ND, sedentary without ND, exercise with ND, and exercise without ND. The animals performed resistance exercise training and received ND two times/week (5 mg/kg, i.m.) for 8 weeks. Adult rats were killed immediately following treatment completion, and aged rats remained untreated until reaching 300 days of age. The adult animals that received ND and performed resistance exercise training showed a higher occurrence of lesions with TLR4 activation. Marked IL-6 expression occurred in the group that performed resistance exercise training. The group exposed to ND showed overexpression of TLR2, TLR4, NOX1, Nrf2, TNF-α, and P38MAPK. The animals that received ND and performed training showed increase levels of NFκB, IRF3, IL-6, TNF-α, and NOX1. TLR2 and TLR4 showed no upregulation in the aged animals. The groups exercise + ND showed lesions in the adult stage and after aging, followed by molecular alterations. We concluded that nandrolone decanoate and resistance exercise training can promote the onset of prostatic tumors in the adult stage, and during aging, activating pathways involved in the inflammatory response.
Assuntos
Anabolizantes/farmacologia , Inflamação/patologia , Nandrolona/análogos & derivados , Condicionamento Físico Animal , Próstata/patologia , Treinamento Resistido , Animais , Inflamação/metabolismo , Interleucina-6/metabolismo , Masculino , NADPH Oxidase 1/metabolismo , NF-kappa B/metabolismo , Nandrolona/farmacologia , Decanoato de Nandrolona , Próstata/efeitos dos fármacos , Próstata/metabolismo , Ratos , Ratos Sprague-Dawley , Receptor 2 Toll-Like/metabolismo , Receptor 4 Toll-Like/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
Thyroid hormones (THs) play key roles in brain development and function. The lack of THs during childhood is associated with the impairment of several neuronal connections, cognitive deficits and mental disorders. Several lines of evidence point to astrocytes as TH targets and as mediators of TH action in the central nervous system; however, the mechanisms underlying these events are still not completely known. In this review, we focus on advances in our understanding of the effects of THs on astroglial cells and the impact of these effects on neurone-astrocyte interactions. First, we discuss the signalling pathways involved in TH metabolism and the molecular mechanisms underlying TH receptor function. Then, we discuss data related to the effects of THs on astroglial cells, as well as studies regarding the generation of mutant TH receptor transgenic mice that have contributed to our understanding of TH function in brain development. We argue that astrocytes are key mediators of hormone actions on development of the cerebral cortex and cerebellum and that the identification of the molecules and pathways involved in these events might be important for determining the molecular-level basis of the neural deficits associated with endocrine diseases.
Assuntos
Astrócitos/fisiologia , Sistema Endócrino/fisiologia , Hormônios Tireóideos/fisiologia , HumanosRESUMO
Astrocytes are target to triiodothyronine (T3) hormone action during rat brain development. In this work, we show that astrocytes from distinct developing brain regions are differently responsive to thyroid hormone. Distinctly from embryonic or newborn cerebral hemisphere and mesencephalic astrocytes, newborn cerebellar and embryonic hippocampal astrocytes do not change their morphology in response of hormone treatment. We also analysed protein synthesis and secretion from these T3-treated astrocytes. The results showed a significant increase in protein synthesis in astrocytes from older brain regions. Maximum effect, however, was observed in cerebral hemisphere astrocytes from newborn rats. The protein secretion effect was also more evident in the cerebral hemisphere as well as in cerebellar astrocytes from newborn rats. In addition, we examined T3 effects on GFAP/vimentin expression by culturing 6-day old cerebellar astrocytes. In this case T3 seems to induce GFAP expression which might be occurring as a first step to astrocyte differentiation.
Assuntos
Astrócitos/ultraestrutura , Encéfalo/crescimento & desenvolvimento , Encéfalo/ultraestrutura , Tri-Iodotironina/fisiologia , Animais , Animais Recém-Nascidos , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Western Blotting , Encéfalo/anatomia & histologia , Diferenciação Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Cerebelo/crescimento & desenvolvimento , Cerebelo/metabolismo , Cerebelo/ultraestrutura , Eletroforese em Gel de Poliacrilamida , Proteína Glial Fibrilar Ácida/biossíntese , Ratos , Tri-Iodotironina/farmacologia , Vimentina/biossínteseRESUMO
Intermediate filament (IF) proteins constitute an extremely large multigene family of developmentally and tissue-regulated cytoskeleton proteins abundant in most vertebrate cell types. Astrocyte precursors of the CNS usually express vimentin as the major IF. Astrocyte maturation is followed by a switch between vimentin and glial fibrillary acidic protein (GFAP) expression, with the latter being recognized as an astrocyte maturation marker. Levels of GFAP are regulated under developmental and pathological conditions. Upregulation of GFAP expression is one of the main characteristics of the astrocytic reaction commonly observed after CNS lesion. In this way, studies on GFAP regulation have been shown to be useful to understand not only brain physiology but also neurological disease. Modulators of GFAP expression include several hormones such as thyroid hormone, glucocorticoids and several growth factors such as FGF, CNTF and TGF beta, among others. Studies of the GFAP gene have already identified several putative growth factor binding domains in its promoter region. Data obtained from transgenic and knockout mice have provided new insights into IF protein functions. This review highlights the most recent studies on the regulation of IF function by growth factors and hormones.
Assuntos
Astrócitos , Proteína Glial Fibrilar Ácida/metabolismo , Substâncias de Crescimento , Proteínas Morfogenéticas Ósseas , Diferenciação Celular , Sistema Nervoso Central , Fatores de Crescimento de Fibroblastos , Fator de Crescimento Transformador beta , Fator de Necrose Tumoral alfa , VimentinaRESUMO
The development of the nervous system is guided by a balanced action between intrinsic factors represented by the genetic program and epigenetic factors characterized by cell-cell interactions which neural cells might perform throughout nervous system morphogenesis. Highly relevant among them are neuron-glia interactions. Several soluble factors secreted by either glial or neuronal cells have been implicated in the mutual influence these cells exert on each other. In this review, we will focus our attention on recent advances in the understanding of the role of glial and neuronal trophic factors in nervous system development. We will argue that the functional architecture of the brain depends on an intimate neuron-glia partnership.
Assuntos
Comunicação Celular/fisiologia , Neuroglia/fisiologia , Neurônios/fisiologia , Animais , Astrócitos/citologia , Astrócitos/fisiologia , Humanos , Neuroglia/citologia , Neurônios/citologia , Neurotransmissores/fisiologia , Oligodendroglia/fisiologia , Células de Schwann/fisiologiaRESUMO
As a result of recent investigations, the cytoskeleton can be viewed as a cytoplasmic system of interconnected filaments with three major integrative levels: self-assembling macromolecules, filamentous polymers, e.g., microtubules, intermediate filaments and actin filaments, and supramolecular structures formed by bundles of these filaments or networks resulting from cross-bridges between these major cytoskeletal polymers. The organization of this biological structure appears to be sensitive to fine spatially and temporally dependent regulatory signals. In differentiating neurons, regulation of cytoskeleton organization is particularly relevant, and the microtubule-associated protein (MAP) tau appears to play roles in the extension of large neuritic processes and axons as well as in the stabilization of microtubular polymers along these processes. Within this context, tau is directly involved in defining neuronal polarity as well as in the generation of neuronal growth cones. There is increasing evidence that elements of the extracellular matrix contribute to the control of cytoskeleton organization in differentiating neurons, and that these regulations could be mediated by changes in MAP activity. In this brief review, we discuss the possible roles of tau in mediating the effects of extracellular matrix components on the internal cytoskeletal arrays and its organization in growing neurons.
Assuntos
Matriz Extracelular/fisiologia , Proteínas Associadas aos Microtúbulos/fisiologia , Neurônios/fisiologia , Proteínas tau/fisiologia , Proteínas do Citoesqueleto , Regulação da Expressão Gênica no Desenvolvimento , Morfogênese , Fatores de Crescimento Neural , NeurogliaRESUMO
We are concerned in this paper with learning classification procedures from known cases. More precisely, we provide a diagnostic model that discriminate between cerebellum-pontine angle (CPA) tumors and otorhinolaryngological (ENT) disorders. Usually, in order to distinguish between CPA tumors and ENT disorders one must perform clinical-neurological examination together with expensive radiological imagery (CT and MRI). The proposed model was obtained through artificial intelligence methods and presented a good accuracy level (88.4%) when tested against new cases, considering only clinical examination without radiological imagery results.
Assuntos
Inteligência Artificial , Neoplasias Cerebelares/diagnóstico , Ângulo Cerebelopontino , Técnicas de Apoio para a Decisão , Otorrinolaringopatias/diagnóstico , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
The higher prevalence of thyroid disease in women suggests that estrogen (E2) might be involved in the pathophysiology of thyroid dysfunction. To approach the question of the effect of stromal cells in the modulation of thyroid epithelial cells activity, we established and characterized a homogeneous stromal cell population (TS7 cells) of rat thyroid gland. These fibroblastic cells synthesize the cytoskeleton proteins α-smooth muscle actin and vimentin, produce basement membrane components and express the cytokine transforming growth factor beta 1 (TGF-ß1). Here, we hypothesized that the effects of E2 on follicular thyroid cells are mediated by TGF-ß1 synthesis and secretion by stromal cells (paracrine action). Thus we investigated the effect of E2 on TGF-ß1 synthesis and its signaling pathway in TS7 cells. In addition, we analyzed the role of TGF-ß1 signaling pathway as mediator of TS7-PC CL3 thyroid epithelial cells interactions. We report that TS7 stromal cells expressed α and ß estrogen receptors (ERα and ERß). Further, both isoforms of TGF-ß1 receptors, TGFRI and TGFRII, were also identified in TS7 cells, suggesting that these cells might be a target for this cytokine in vitro. Treatment of TS7 cells with E2 induced both synthesis and secretion of TGF-ß1. This event was followed by phosphorylation of the transcription factor Smad2, a hallmark of TGF-ß1 pathway activation. Co-culture of PC CL3 cells onto TS7 cells monolayers yielded round aggregates of PC CL3 cells surrounded by TS7 cells. TS7 cells induced a decrease in iodide uptake by PC CL3 cells, probably by a mechanism involving TGF-ß1. Moreover, E2 affected synthesis and organization of the extracellular matrix (ECM) components, tenascin C and chondroitin sulfate, in these co-culture cells. Our results point to the TGF-ß1/Smad-2 signaling pathway as a putative target of estrogen actions on thyroid stromal cells and contribute to understanding the interplay between stromal and follicular cells in thyroid physiology.
Assuntos
Estradiol/metabolismo , Transdução de Sinais , Células Estromais/metabolismo , Glândula Tireoide/citologia , Fator de Crescimento Transformador beta1/genética , Animais , Forma Celular , Sobrevivência Celular , Células Cultivadas , Técnicas de Cocultura , Proteínas do Citoesqueleto/metabolismo , Receptor alfa de Estrogênio/metabolismo , Receptor beta de Estrogênio/metabolismo , Matriz Extracelular/metabolismo , Feminino , Ratos , Ratos Wistar , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Proteínas Smad/metabolismo , Glândula Tireoide/metabolismo , Transcrição Gênica , Fator de Crescimento Transformador beta1/metabolismoRESUMO
AIMS: To test indigenous Saccharomyces cerevisiae as starters to produce cachaça in large-scale in a traditional distillery, establishing the period in which, each strain predominates in the vats, chemical composition and sensory attributes of the beverage, and to compare these data with vats prepared by spontaneous fermentation. METHODS AND RESULTS: Strains were evaluated for kinetic fermentation parameters, permanence in vats, volatile compound production, and sensory attributes for the cachaças produced. In general the vats in which starter strains were used, no difference in restriction mitochondrial DNA (mtDNA) profiles of isolates was observed. In the vats in which spontaneous fermentation occurred, different mtDNA restriction profiles were observed. Most of the non-Saccharomyces species isolated could be regarded as contaminants of fermentation. All cachaças produced, despite being recently distilled and with differences in their chemical composition, were well accepted by the judges. CONCLUSIONS: It was possible to detect the differences in the fermentation capacities of S. cerevisiae strains, in their relative abundances at different time periods, and in the chemical compositions and sensory attributes of the resulting beverages. SIGNIFICANCE AND IMPACT OF THE STUDY: The indigenous strains utilized to prepare cachaça have shown potential to be used as starters of this traditional fermentation process.
Assuntos
Microbiologia de Alimentos , Microbiologia Industrial , Saccharomyces cerevisiae/fisiologia , Vinho , Fermentação , Genes Fúngicos , Saccharomyces cerevisiae/genética , EspanhaRESUMO
The population dynamics of Staphylococcus spp. was studied during the ripening of Canastra Minas cheese at three farms located in the State of Minas Gerais, Brazil. The presence of coagulase (coa), thermonuclease (nuc), and enterotoxin (sea, seb, sec, and sed) genes was investigated in Staphylococcus strains isolated during the 60-day cheese-ripening period. The presence of the staphylococcal enterotoxins A, C, and D was also investigated in the cheese samples. Cheese samples that were matured for 0, 7, 15, 30, and 45 days presented staphylococci counts from 10³ to 10(8)cfu/g. All isolates considered coagulase-positive by physiological tests had the coa gene. However, no association was observed between the results obtained with biochemical tests and those obtained by PCR using gene-specific primers for coagulase-negative strains. Coagulase and thermonuclease genes occurred simultaneously in 41.3 percent of Staphylococcus spp. tested. None of the investigated Staphylococcus strains expressed enterotoxins SEA, SEB, SEC, and SED. Enterotoxins A, C, and D were not detected in any of the cheese samples.
Estudou-se a dinâmica das populações de Staphylococcus spp. durante a maturação do queijo Canastra, em três fazendas localizadas no estado de Minas Gerais. A presença dos genes que codificam para a produção das enzimas coagulase (coa), termonuclease (nuc) e produção de enterotoxinas (sea, seb, sec e sed), em linhagens de Staphylococcus isoladas durante os 60 dias de maturação do queijo foi analisada. Também foi investigada a presença de enterotoxina estafilocócica A, C e D nas amostras de queijo. As amostras de queijo com 0, 7, 15, 30 e 45 dias de maturação apresentaram contagens de Staphylococcus spp. entre 10³ e 10(8)ufc / g. Todos os isolados coagulase positivo nos testes fisiológicos apresentaram o gene coa. Não foi observada associação entre os resultados obtidos com os testes bioquímicos e aqueles obtidos com a PCR usando iniciadores gene-específicos para linhagens coagulase negativa. Os genes da coagulase e termonuclease ocorreram simultaneamente em 41,3 por cento dos Staphylococcus spp. testados. Nenhum dos isolados de Staphylococcus apresentou os genes que codificam para a produção das enterotoxinas SEA, SEB, SEC ou SED. As enterotoxinas A, C ou D não foram detectadas em nenhuma das amostras de queijo analisadas.
Assuntos
Humanos , Queijo/classificação , Staphylococcus , Coagulase/metabolismo , Enterotoxinas/toxicidade , Fisiologia/métodosRESUMO
In order to investigate the influence of neuron-glia interaction on astrocyte differentiation, we used a transgenic mouse bearing part of the gene promoter of the astrocytic maturation marker GFAP linked to the beta-galactosidase (beta-gal) reporter gene. Addition of embryonic cerebral hemisphere (CH) neurons to transgenic CH astrocyte monolayers increased by 50-60% beta-gal positive cell number. Such event was dependent on the brain regional origin of the neurons and was followed by an arrest of astrocytes from the cell cycle and induction of glial differentiation. Time-course assays demonstrated that maximum effect was observed after 24 h of coculture. Addition of conditioned medium (CM) derived from CH neurons also increased beta-gal positive CH astrocytic cell number. However, such CM had no effect on midbrain and cerebellum astroglia. Together, these data suggest that neurons secrete brain region-specific soluble factors which induce GFAP gene promoter, as measured by beta-gal expression, thus suggesting that neuron-glia interaction might induce the astrocytic differentiation program.
Assuntos
Astrócitos/fisiologia , Proteína Glial Fibrilar Ácida/genética , Neurônios/fisiologia , Regiões Promotoras Genéticas/fisiologia , Animais , Encéfalo/citologia , Encéfalo/metabolismo , Encéfalo/fisiologia , Comunicação Celular/fisiologia , Ciclo Celular/fisiologia , Células Cultivadas , Difusão , Expressão Gênica/fisiologia , Regulação da Expressão Gênica/fisiologia , Óperon Lac/fisiologia , Camundongos , Camundongos Transgênicos/genética , Neuroglia/fisiologia , Neurônios/metabolismo , Fatores de TempoRESUMO
Thyroid hormones are important for neurogenesis and gliogenesis during brain development. We have previously demonstrated that triiodothyronine (T3) treatment induced proliferation in primary culture astrocytes derived from the cerebellum of neonatal rats. Conditioned medium obtained from those T3-treated astrocytes (T3CM) mimicked the effect of hormonal treatment on these cells. Because neuron-glia interaction plays an important role in brain development, we tested the ability of such T3-glial CM to influence neuronal physiology. With that aim, neurons from 19-day embryonic cerebella were cultivated for 24 h in the presence of CM obtained from T3-treated cerebellar astrocytes. Interestingly, the cerebellar neuronal population increased by 60-80% in T3CM. Addition of 5 microM forskolin enhanced the responsiveness of cerebellar neurons to astrocytes T3CM, but it did not interfere with neuronal survival in control medium. Conversely, inhibition of adenylate cyclase by its specific inhibitor, SQ22536, reversed the T3CM effect on neurons. These data strongly suggest that cAMP signal transduction pathways might be implicated in such an event. Analysis of bromodeoxyuridil incorporation revealed that the increase in neuron number in T3CM was partially due to neuron proliferation, because the proliferation index was three times higher in T3CM than in control medium. Neutralizing antibody assays demonstrated that T3CM effects on neurons are due, at least in part, to the presence of tumor necrosis factor-beta and epidermal growth factor. Thus, we report here a novel molecular mechanism of action of thyroid hormone on cerebellar neuronal cells: Thyroid hormone induces astrocytes to secrete growth factors that can interfere with neuronal proliferation via a paracrine pathway.
Assuntos
Astrócitos/efeitos dos fármacos , Cerebelo/citologia , Neurônios/fisiologia , Tri-Iodotironina/farmacologia , Animais , Animais Recém-Nascidos , Astrócitos/fisiologia , Contagem de Células , Divisão Celular/efeitos dos fármacos , Células Cultivadas , Colforsina/farmacologia , Meios de Cultivo Condicionados/farmacologia , AMP Cíclico/fisiologia , Inibidores do Crescimento/farmacologia , Fatores de Crescimento Neural/imunologia , Fatores de Crescimento Neural/fisiologia , Ratos , Ratos WistarRESUMO
A vinblastine-resistant Leishmania amazonensis cell line (RV100) which exhibits cross-resistance to the unrelated drug adriamycin, and thus is considered to be multidrug resistant (MDR), was isolated after stepwise selection with increasing concentrations of vinblastine. This phenotype was partially reverted by the calcium channel antagonist verapamil. Drug transport studies using the hydrophobic fluorescent dye rhodamine 123 demonstrated that the MDR cell line has a reduced dye accumulation due to an increased efflux. Furthermore, DNA and RNA hybridization studies demonstrated that a gene (lamdr1), homologous to ldmdr1 and lemdr1, was overexpressed and amplified within 27 kb extrachromosomal DNA circles (V-circles) in these cells. An independent cell line, RA5000, which was selected for resistance to adriamycin and was not cross-resistant to vinblastine, accumulated normal levels of rhodamine 123 and did not contain amplified DNA or overexpressed RNA of mdr-related sequences.
Assuntos
Antiprotozoários/farmacologia , Doxorrubicina/farmacologia , Resistência a Múltiplos Medicamentos/genética , Leishmania/efeitos dos fármacos , Verapamil/farmacologia , Vimblastina/farmacologia , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Animais , Linhagem Celular , DNA de Protozoário , Eletroforese em Gel de Campo Pulsado , Amplificação de Genes , Genes de Protozoários , Leishmania/genética , Técnicas de Sonda Molecular , Fenótipo , RNA de Protozoário , Rodamina 123 , Rodaminas/metabolismoRESUMO
O objetivo deste trabalho foi avaliar a eficiência do método de regressão em detectar QTL com base na utilização de dados da estrutura de família (irmãos completos e meios-irmãos), como aqueles gerados em um núcleo MOET. Foram simulados dados fenotípicos e genotípicos em uma estrutura de núcleo MOET fechado de seleção. Três arquivos foram analisados, contendo: a) informações conjuntas de irmãos completos e meios-irmãos; b) apenas informações de irmãos completos e c) apenas informações de meios-irmãos. Verificou-se que o método da regressão, para dados discretos ou contínuos, foi capaz de detectar associações entre marcador e QTL em níveis bastante expressivos de significância (P<0.001 e P<0,0001), quando se utilizou o arquivo que continha informações conjuntas de irmãos completos e meios-irmãos. Os resultados indicaram a possibilidade de utilização dessa metodologia para estudos de detecção/validação de QTL em rebanhos ou núcleos de seleção que utilizam MOET.
The objective of this study was to evaluate the efficiency of the regression method to detect QTL using data from full and half-sib families, like those generated in a MOET nucleus. For this study, genotypic and phenotypic data were simulated in a structure of a closed selection MOET nucleus. Three files were analyzed containing: a) the joint information of full and half sibs; b) only full sibs data; and c) only half sibs data. The method of regression, for continuous or discrete data, was able to detect associations of marker and QTL in very expressive levels of significance (P<0.001 P<0.0001), when the file containing the joint information of full and half sisters was used. The results indicated the possibility of using this methodology for studies of QTL detection / validation in MOET nucleus or herds under selection.