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1.
Am J Primatol ; 73(1): 91-5, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20973084

RESUMO

This is a reply to Richard Lawler's commentary on our previous work [Lawler, 2011; this issue] in which he develops a set of operational models to test socioecological theories of the evolutionary importance of feeding competition. We strongly agree that we need to critically re-evaluate the basic assumptions of all models of primate sociality, and to verify the explanatory power of alternative models. We also feel Lawler's commentary provides an important opportunity to broaden the debate concerning the fundamental roles of cooperation, competition, and aggression in understanding primate social systems. Lawler provides a number of suggestions as to how models developed in primate socioecology might be tested. We agree with these suggestions, make further suggestions, and call for specific operational definitions so that researchers might begin to develop and test various methodologies. However, we also call for testing alternative theories. Current socioecological theory is based on the assumption that competition and positive selection is always in operation and has driven the evolution of living organisms. We believe that this "explanation of choice" often is treated as an assumed truth to which data are forced to fit, rather than being seen as a theory to be tested. Furthermore, we agree with Weiss and Buchanan [2009. The Mermaid's Tale: Four Billion Years of Cooperation in the Making of Living Things] that on ecological and developmental scales, where organisms actually live out their lives, cooperation may play a more fundamental role than competition.


Assuntos
Primatas/psicologia , Ciclos de Atividade , Agressão , Animais , Antropologia Cultural/métodos , Evolução Biológica , Comportamento Cooperativo , Comportamento Alimentar , Modelos Biológicos , Comportamento Social
2.
Am J Phys Anthropol ; 128(1): 84-97, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15778981

RESUMO

The idea that competition and aggression are central to an understanding of the origins of group-living and sociality among human and nonhuman primates is the dominant theory in primatology today. Using this paradigm, researchers have focused their attention on competitive and aggressive behaviors, and have tended to overlook the importance of cooperative and affiliative behaviors. However, cooperative and affiliative behaviors are considerably more common than agonistic behaviors in all primate species. The current paradigm often fails to explain the context, function, and social tactics underlying affiliative and agonistic behavior. Here, we present data on a basic question of primate sociality: how much time do diurnal, group-living primates spend in social behavior, and how much of this time is affiliative and agonistic? These data are derived from a survey of 81 studies, including 28 genera and 60 species. We find that group-living prosimians, New World monkeys, Old World monkeys, and apes usually devote less than 10% of their activity budget to active social interactions. Further, rates of agonistic behaviors are extremely low, normally less than 1% of the activity budget. If the cost to the actors of affiliative behavior is low even if the rewards are low or extremely variable, we should expect affiliation and cooperation to be frequent. This is especially true under conditions in which individuals benefit from the collective environment of living in stable social groups.


Assuntos
Evolução Biológica , Comportamento Cooperativo , Primatas/psicologia , Conformidade Social , Ciclos de Atividade , Agressão , Animais , Anomia (Social) , Antropologia Cultural/métodos , Cebidae/psicologia , Processos Grupais , Strepsirhini/psicologia
3.
Am J Phys Anthropol ; 120(2): 182-94, 2003 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12541335

RESUMO

Over 15 field seasons (1987-2001), we collected census and life-history data on a population of individually identified ring-tailed lemurs at the Beza Mahafaly Reserve, Madagascar. No significant difference was found in population size over the study period, though a marked decline in the population occurred following a 2-year drought. The population rebounded rapidly after the immediate postdrought period. There was nearly a complete replacement of individuals over the study period. Average group size is 11.5 animals, and adult male to female sex ratio is 0.92. Most females reproduce annually, and the average fecundity rate is 84.3%. The greatest variability in fecundity is found among old females. We suggest that ring-tailed lemur females follow an "income breeding" strategy, i.e., females use maximum resources during reproduction rather than relying on fat stores, as do "capital breeders." Infant mortality to 1 year of age in a nondrought year is 52%, higher than infant mortality in small to medium-sized anthropoids. The oldest known female was 18 years old in 2001. We suggest that 18-20 years may represent the maximum life-span for wild ring-tailed lemurs. Because males regularly emigrate from the population, we have no data regarding male life-span; however, there is some indication that males do not survive as long as females. Group fission has occurred three times: twice from one parent group living in the driest area of the reserve, with the most dispersed food resources. We suggest that the reproductive strategy that has evolved in this species, wherein females reproduce early in life and annually until old age, is a response to the unusual climate and environmental conditions under which Lemur catta has evolved.


Assuntos
Comportamento Animal , Ecologia , Lemur , Animais , Demografia , Feminino , Madagáscar , Masculino
4.
Am J Phys Anthropol ; 117(2): 122-32, 2002 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11815947

RESUMO

Data are presented on dental and general health for seven groups of wild ring-tailed lemurs, Lemur catta, from the Beza Mahafaly Reserve, in southern Madagascar. As part of a study of population demography, adults were captured, collared, and tagged, and biometric measurements, dental casts, and analyses of dental and general health were made. Results indicate that patterns of dental health vary by individual, age, sex, and habitat. Prime adults show more dental attrition than young adults. Prime males living in more marginal habitats show greater mean attrition than those living in richer habitats. Dental damage, specifically to the toothcomb, indicates that mechanical stresses to this region may include the initial harvesting of foods, in addition to grooming. Males exhibit more evidence of past trauma, including scars and chipped teeth. These results indicate that environmental as well as social factors, such as female dominance, may lead to sex differences in health patterns among lemurs.


Assuntos
Dieta , Nível de Saúde , Lemur , Abrasão Dentária , Fatores Etários , Animais , Animais Selvagens , Demografia , Feminino , Masculino , Fatores Sexuais , Comportamento Social
5.
Genesis ; 31(1): 1-5, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11668671

RESUMO

The production of transfected fish embryos requires expertise in injecting the fertilized eggs and/or expensive equipment for electroporation or microprojectiles. This article demonstrates that by exposure to DNA constructs conjugated with transfecting reagents dechorionated Danio rerio embryos are capable of acquiring extracellular DNA and expressing reporter genes. Embryos incubated with pCMVluc complexed with GeneJammer or GenePORTER expressed luciferase 24-48 h after exposure. pCMVGFP DNA mixed with the same agents generated embryos that exhibited differential patterns of expression of green fluorescent protein (GFP). Embryonic development varied depending on the procedure employed and the reporter gene utilized. Expression of the luciferase gene did not interfere with the subsequent development of the embryos. In contrast, the embryos expressing a high level of GFP were affected, probably due to a very active promoter. These results demonstrate the ease of obtaining transfected fish embryos, which facilitate the mass production of new genotypes and extend the procedure to laboratories with limited resources.


Assuntos
Proteínas de Ligação a DNA/metabolismo , DNA/metabolismo , Embrião não Mamífero/metabolismo , Peixe-Zebra/embriologia , Animais , Técnicas de Cultura/métodos , Proteínas de Ligação a DNA/genética , Expressão Gênica , Proteínas de Fluorescência Verde , Luciferases/genética , Luciferases/metabolismo , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Fatores de Tempo , Transfecção , Peixe-Zebra/genética
6.
Am J Phys Anthropol ; 114(3): 215-23, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11241187

RESUMO

Detailed descriptions of the dentition of many strepsirhine primate taxa are rare, despite their importance in understanding primate evolutionary biology. While several researchers have provided detailed morphological descriptions of ring-tailed lemur dentition (e.g., Schwartz and Tattersall [1985] Am. Mus. Nat. Hist. Anthropol. Pap. 60:1-100; Tattersall and Schwartz [1991] Am. Mus. Nat. Hist. Anthropol. Pap. 69:2-18), there are few studies (e.g., Eaglen [1986] Am. J. Phys. Anthropol. 71:185-201) that present quantitative data on the dentition of this species. Furthermore, prior analyses were based on museum specimens from various populations and locations. We present here quantitative and morphological data on the dentition of a population of wild Lemur catta from Beza Mahafaly Special Reserve, Madagascar. Measurements were made on dental casts (n = 39) taken from living members of this L. catta population. Our analysis indicates that no significant (P > 0.05) sexual dimorphism exists for the 30 dental measurements collected. These data support the generalizations (e.g., Plavcan and van Schaik [1994] Evol. Anthropol. 2:208-214; Kappeler [1996] J. Evol. Biol. 9:43-65) that little sexual dimorphism in dentition exists among Malagasy strepsirhines. In addition, the overall patterns of metric variation in this sample compare favorably with patterns seen among other primates, e.g., premolar measurements varying more than molars (e.g., Gingerich [1974] J. Paleontol. 48:895-903). However, there is a degree of intraspecific morphological variation indicated, with one of the morphological traits discussed in other studies as being species-specific for L. catta (absence of P(4) metaconids) observed to vary between specimens. Because the patterns of variation seen in this sample are from a known breeding population, the data presented here provide an important reference for interpreting and understanding the fossil record.


Assuntos
Dentição , Lemur/anatomia & histologia , Animais , Feminino , Lemur/crescimento & desenvolvimento , Madagáscar , Masculino , Mandíbula/anatomia & histologia , Mandíbula/crescimento & desenvolvimento , Maxila/anatomia & histologia , Maxila/crescimento & desenvolvimento , Caracteres Sexuais , Especificidade da Espécie
7.
Occup Med ; 12(1): 107-17, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9153056

RESUMO

Company health and safety professionals must advise workers of the potential hazards of workplace chemicals. Yet it is difficult to develop one, consistent corporate labeling strategy for worldwide use. This chapter describes one company's approach to devising a corporate policy satisfying all criteria.


Assuntos
Indústria Farmacêutica/legislação & jurisprudência , Substâncias Perigosas/normas , Doenças Profissionais/prevenção & controle , Saúde Ocupacional/legislação & jurisprudência , Rotulagem de Produtos/normas , United States Occupational Safety and Health Administration/legislação & jurisprudência , Comunicação , Indústria Farmacêutica/normas , Monitoramento Ambiental , Substâncias Perigosas/efeitos adversos , Humanos , Medição de Risco , Estados Unidos
8.
Rev. Soc. obstet. ginecol. B.Aires ; 75(923): 363-73, dic. 1996. ilus
Artigo em Espanhol | BINACIS | ID: bin-20189

RESUMO

Objetivo: evaluar la experiencia de la sección endoscopia y ginecología infanto juvenil en el diagnóstico y tratamiento laparoscópico de las afecciones infanto juveniles. Procedimiento: análisis retrospectivo de las historias clínicas de las pacientes menores de 18 años sometidas a una laparoscopia entre 1987 y 1994. Lugar de realización: Hospital de Clínicas José de San Martín, Servicio de Ginecología, secciones cirugía laparoscópica y ginecología infanto juvenil. Resultados: El 72,5 por ciento de la patología se dividió entre amenorreas 1º y algias pelvianas. El resto se repartió en tumores de ovario 12,5 por ciento, abdomen agudo 7,5 por ciento, amenorreas 2º 5 por ciento, búsqueda de tumor primitivo en un caso 2,5 por ciento. Se efectuó cirugía laparoscópica en el 32,5 por ciento de las


Assuntos
Criança , Humanos , Feminino , Adolescente , Amenorreia/diagnóstico , Neoplasias Ovarianas/diagnóstico , Abdome Agudo/diagnóstico , Laparoscopia/estatística & dados numéricos , Laparoscopia/estatística & dados numéricos , Amenorreia/cirurgia , Amenorreia/etiologia , Endometriose/cirurgia , Endometriose/diagnóstico , Dor Pélvica/etiologia
9.
Rev. Soc. obstet. ginecol. B.Aires ; 75(923): 363-73, dic. 1996. ilus
Artigo em Espanhol | LILACS | ID: lil-205024

RESUMO

Objetivo: evaluar la experiencia de la sección endoscopia y ginecología infanto juvenil en el diagnóstico y tratamiento laparoscópico de las afecciones infanto juveniles. Procedimiento: análisis retrospectivo de las historias clínicas de las pacientes menores de 18 años sometidas a una laparoscopia entre 1987 y 1994. Lugar de realización: Hospital de Clínicas José de San Martín, Servicio de Ginecología, secciones cirugía laparoscópica y ginecología infanto juvenil. Resultados: El 72,5 por ciento de la patología se dividió entre amenorreas 1º y algias pelvianas. El resto se repartió en tumores de ovario 12,5 por ciento, abdomen agudo 7,5 por ciento, amenorreas 2º 5 por ciento, búsqueda de tumor primitivo en un caso 2,5 por ciento. Se efectuó cirugía laparoscópica en el 32,5 por ciento de las patologías encontradas. Estas fueron: 4 gonadectomías, 2 tratamientos laparoscópicos de endometriosis, 1 hemihisterectomia en un útero doble, 1 omentectomía y 2 quistectomías. Los 3 abdómenes agudos hallados, también fueron resueltos por esta vía. Conclusión: Consideramos que la laparoscopia cumple actualmente un importante rol en el diagnóstico y tratamiento en la patología infanto juvenil, y que sus indicaciones se han incrementado, y seguirán incrementándose con el perfeccionamiento de esta técnica


Assuntos
Criança , Humanos , Feminino , Adolescente , Abdome Agudo/diagnóstico , Amenorreia/diagnóstico , Laparoscopia/estatística & dados numéricos , Laparoscopia/estatística & dados numéricos , Neoplasias Ovarianas/diagnóstico , Amenorreia/etiologia , Amenorreia/cirurgia , Dor Pélvica/etiologia , Endometriose/diagnóstico , Endometriose/cirurgia
10.
Fundam Appl Toxicol ; 26(1): 20-31, 1995 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-7657059

RESUMO

Much of the data which have been generated on in vitro alternatives to the Draize eye irritation test have dealt with compounds within a specific chemical class or product category. However, in the pharmaceutical industry, it is often necessary to evaluate materials which are not related in structure or properties. It was thus decided to evaluate a diverse series of chemicals in seven in vitro methods for estimating ocular irritation. Thirty-seven test materials were chosen to represent a broad range of pH, solubility, and in vivo irritation potential. Assays were chosen to include as many different types of end points as practical. The group of assays was composed of TOPKAT (assessing structure-activity relationships), bovine corneal opacity-permeability (BCO-P; corneal opacity/toxicity), Eytex (protein coagulation), neutral red uptake (cytotoxicity), MTT in living dermal equivalent (cytotoxicity), Microtox (cytotoxicity in bacteria), and CAMVA (inflammation/toxicity). The results of the study indicated that, in general, the cytotoxicity end points did not correlate well with the in vivo data. The BCO-P, CAMVA, and Eytex assays had the best overall concordance (88.9, 75.8, and 75.0%, respectively) with this set of compounds. Estimation of irritation potential based on structure-activity (TOPKAT) was possible for only approximately 50% of the compounds; however, the assay showed 100% sensitivity (i.e., no false negatives), but low specificity (i.e., negatives correctly identified only 54.5% of the time). These data suggest that for screening of chemicals of diverse structure and properties, the more mechanism-based assays, as opposed to general cytotoxicity assays, hold more promise and should be further evaluated.


Assuntos
Alternativas aos Testes com Animais , Olho/efeitos dos fármacos , Irritantes/toxicidade , Testes de Toxicidade , Animais , Bovinos , Sobrevivência Celular/efeitos dos fármacos , Embrião de Galinha , Estudos de Avaliação como Assunto , Humanos , Técnicas In Vitro , Valor Preditivo dos Testes , Sensibilidade e Especificidade , Relação Estrutura-Atividade
11.
Am J Phys Anthropol ; 96(2): 133-41, 1995 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-7755104

RESUMO

Macaque monkeys (Macaca fascicularis) were introduced to the island of Mauritius approximately 400 years ago. This study compares the mitochondrial DNA of macaques on Mauritius with those from Indonesia and the Philippines. The goal is to measure the amount of evolutionary change that has occurred in this isolated population over 400 years, and to address questions regarding the origin of the Mauritian founders. Amplification of the control region of the mitochondrial genome via the polymerase chain reaction yielded an 1800 base pair DNA fragment which was surveyed for variation using restriction endonucleases. Fifty-two macaques were separated into 17 haplotypes by mapping the restriction sites. No haplotypes were shared among the three populations, and only two closely related haplotypes appeared in the Mauritian sample. Nucleotide variation in the mitochondrial DNA in the Mauritian sample was 10-fold less than the Indonesian and Filipino samples. In contrast, allozyme data estimates of genetic diversity on Mauritius are similar to populations from the ancestral range. The evidence of the more severe bottleneck as measured by mitochondrial data may be explained in part by almost exclusive male dispersal in this species, and may support models of founder events in which rapid population growth prevents substantial loss of nuclear variation. The mitochondrial evidence supports the morphologically and historically based hypothesis that the original founders came from Indonesia.


Assuntos
DNA Mitocondrial/genética , Variação Genética , Macaca fascicularis/genética , Animais , Sequência de Bases , Efeito Fundador , Haplótipos , Indonésia , Maurício , Dados de Sequência Molecular , Filipinas , Reação em Cadeia da Polimerase
12.
Biotechniques ; 16(3): 463-9, 1994 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-8185921

RESUMO

This paper describes a new strategy for positioning specific loci on known genomic maps or for generating high-resolution physical maps of organisms that are susceptible to transposable elements. The strategy does not require cloning and thus saves time and effort. It is based on isolating cell lines containing appropriate insertions of a DNA element (transposon) carrying a selectable marker and one or more restriction sites. DNA from independent cell lines is digested to completion with a restriction enzyme that cuts within the transposon and the adjacent genomic DNA. The fragments thus produced are analyzed by partial digestions with a panel of restriction enzymes, separated and probed sequentially with oligonucleotides complementary to the ends of the transposon. Algorithms that compare and order the different restriction fingerprints are used to either place the unknown locus on an existing restriction map or, in the case of a new genome, to form contigs to generate a map. The usefulness of this strategy was demonstrated by mapping an Escherichia coli insertion mutation that was difficult to map by more standard procedures.


Assuntos
Mapeamento Cromossômico/métodos , Mutagênese Insercional , Algoritmos , Sequência de Bases , Southern Blotting , Clonagem Molecular , Enzimas de Restrição do DNA , Elementos de DNA Transponíveis , Desoxirribonuclease EcoRI , Escherichia coli/genética , Dados de Sequência Molecular , Mapeamento por Restrição
13.
Respir Physiol ; 93(3): 261-78, 1993 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8235126

RESUMO

Air velocity was measured at end airways of hollow replicate casts of the human tracheobronchial tree in order to determine the flow distribution within casts extending to 3 mm diameter airways. Measurements were made by hot-wire anemometry for constant inspiratory flow rates of 7.5, 15, 30 and 60 L.min-1. Average flow distribution among the lung lobes was as follows: right upper, 18.5%; right middle, 9.2%; right lower, 32.3%; left upper, 15.7%; and left lower, 24.3%. An empirical model derived from the experimental flow distribution data demonstrated the effect of various morphometric parameters of the hollow cast on the distribution of airflow. Airway cross-sectional area, branching angle and total path-length were found to have the greatest influence. As the tracheal flow rate decreased from 60 to 7.5 L.min-1, the influence of branching angle was reduced, while total path-length became more influential. These results provide evidence for the transition of flow regimes within the TB tree within normal physiological flow ranges.


Assuntos
Brônquios/fisiologia , Modelos Anatômicos , Ventilação Pulmonar/fisiologia , Traqueia/fisiologia , Adulto , Humanos , Masculino , Modelos Biológicos
14.
Regul Toxicol Pharmacol ; 15(3): 291-306, 1992 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-1509122

RESUMO

Occupational exposure limits (OELs) serve occupational health professionals as benchmarks for a healthy work environment. OELs are generally developed by manufacturers for substances which are not subject to governmental regulation or which have not been evaluated by consensus organizations such as the American Conference of Governmental Industrial Hygienists. This review is intended to serve as a practical guide to the standard-setting process. The discussion encompasses the evaluation of data, the different methods used for calculating limits, and the application of these limits to the workplace. The need for additional research to enhance the reliability of current methods is also discussed.


Assuntos
Substâncias Perigosas/toxicidade , Concentração Máxima Permitida , Exposição Ocupacional/normas , Substâncias Perigosas/farmacocinética , Humanos , Exposição Ocupacional/análise , Pesquisa , Estados Unidos , United States Environmental Protection Agency , United States Occupational Safety and Health Administration
15.
Science ; 248(4952): 212-5, 1990 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-17740137

RESUMO

Madagascar is biologically one of the richest areas on Earth, and its plants and animals are among the most endangered. Satellite images and vegetation maps based on earlier aerial photographs were used to determine the extent of eastern rain forests in Madagascar and to monitor the rate of deforestation over a 35-year period. In 1985, 3.8 million hectares of rain forest remained, representing only 50 percent of the 7.6 million hectares existing in 1950 and 34 percent of the estimated orignal extent (11.2 million hectares). Between 1950 and 1985, the rate of deforestation averaged 111,000 hectares per year. Deforestation was most rapid in areas with low topographic relief and high population density. If cutting of forests continues at the same pace, only forests on the steepest slopes will survive the next 35 years.

16.
J Bacteriol ; 171(3): 1235-44, 1989 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-2522089

RESUMO

To analyze lambda repressor function and structure, antibodies were generated with synthetic peptides corresponding to sequences believed to be involved in prophage induction. These site-directed antibodies seemed to recognize preferentially the primary sequence of repressor because they reacted better in competition experiments with the oligopeptide and with the partially denatured forms of repressor than with the native molecules. This information, together with the characteristic ability of the antibodies to immunoprecipitate or react with repressor in immunoblots, allowed us to infer some conformational properties of the specific regions that the antibodies recognized. The antibodies reacted less with some mutant repressors that had a single amino acid substitution within the cognitive sequences. RecA-catalyzed cleavage of repressor was inhibited to different extents in relation to the proportion of repressor that each antipeptide immunoglobulin G (IgG) was able to immunoprecipitate. The antipeptide IgGs did not affect specific binding of repressor to operator DNA, whereas the antirepressor IgG was inhibitory. The three different IgGs competed for binding to repressor in an enzyme-linked immunosorbent assay additivity test, which suggested that the three regions of conserved amino acids are probably located on the same side of the carboxyl domain of repressor and possibly close together in the tertiary structure.


Assuntos
Bacteriófago lambda/genética , Escherichia coli/genética , Proteínas Repressoras/genética , Fatores de Transcrição/genética , Sequência de Aminoácidos , Anticorpos , Complexo Antígeno-Anticorpo , Ensaio de Imunoadsorção Enzimática , Imunoglobulina G , Cinética , Dados de Sequência Molecular , Fragmentos de Peptídeos/análise , Peptídeo Hidrolases , Recombinases Rec A/fisiologia , Proteínas Repressoras/imunologia , Proteínas Repressoras/metabolismo
17.
Chest ; 93(3): 595-8, 1988 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-3342671

RESUMO

The possible contribution of computed tomography (CT) in the management of patients with solitary pulmonary nodules (SPNs) or masses was reviewed retrospectively in 65 patients undergoing fiberoptic bronchoscopy (FOB). Nodules were evaluated by size, location, surface contour, and the presence in cross-section of a bronchus leading to or contained within the nodule or mass, a "positive bronchus sign." Thirty-five lesions were associated with a positive bronchus sign; 21 of 35 (60 percent) were diagnosed endoscopically, (p = .027); of 30 cases with a negative bronchus sign, only ten (30 percent) had a diagnosis made by FOB (p = .034). It is concluded that CT may be of use in the routine evaluation of pulmonary nodules, prior to bronchoscopy, especially in cases for which histologic evaluation is essential, especially to determine the presence or absence of a CT bronchus sign.


Assuntos
Broncoscopia , Neoplasias Pulmonares/diagnóstico , Tomografia Computadorizada por Raios X , Biópsia , Estudos de Avaliação como Assunto , Tecnologia de Fibra Óptica , Humanos , Pulmão/patologia , Neoplasias Pulmonares/patologia , Estudos Retrospectivos
20.
Mutat Res ; 160(3): 179-93, 1986 May.
Artigo em Inglês | MEDLINE | ID: mdl-2938000

RESUMO

We measured the production of untargeted mutations in the cI and cII genes of untreated lambda phage undergoing a lytic cycle in UV-irradiated bacterial hosts. As previously shown, treatment with 4 micrograms/ml of rifampicin during post-irradiation incubation inhibited amplification of the RecA protein in these cells. In addition, we observed a decreased mutation rate compared to the untreated, irradiated bacteria. Treatment with 4 micrograms/ml or 8 micrograms/ml rifampicin did not prevent the UV induction of the umuDC operon, as judged by assay of beta-galactosidase activity in a umuC-lacZ fusion strain. In contrast, the UV-induction of beta-galactosidase in the sulA-lacZ fusion strain was decreased by 4 micrograms/ml rifampicin. The inhibition of untargeted mutagenesis by this drug treatment was also observed in a strain constitutive for SOS functions (lexA (Def)) as well as in a RecA-overproducing plasmid strain, suggesting the requirement of other factor(s) in wild-type recA+ cells. An htpR165-carrying strain, that blocks induction of heat-shock proteins, exhibited normal UV-promoted mutagenesis. A correlation was observed between the cellular concentration of RecA protein, increased spontaneously by a temperature shift in a lexA(Ts) strain, and the extent of UV-promoted untargeted mutagenesis. These results suggest a mechanistic role of RecA protein in this process.


Assuntos
Escherichia coli/genética , Recombinases Rec A/fisiologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/fisiologia , Bacteriófago lambda/genética , Bacteriófago lambda/metabolismo , Bacteriófago lambda/efeitos da radiação , Escherichia coli/metabolismo , Genes Bacterianos/efeitos da radiação , Genes Virais/efeitos da radiação , Proteínas de Choque Térmico/fisiologia , Mutação , Recombinases Rec A/análise , Rifampina/farmacologia , Temperatura , Transcrição Gênica/efeitos dos fármacos , Transcrição Gênica/efeitos da radiação , Raios Ultravioleta , Proteínas Virais/genética
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