780 resultados para leaf-eating


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Although the complete genome sequences of over 50 representative species have revealed the many duplicated genes in all three domains of life(1-4), the roles of gene duplication in organismal adaptation and biodiversity are poorly understood. In addition,

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Physiological functions of human genes may be studied by gene-knockout experiments in model organisms such as the mouse. This strategy relies on the existence of one-to-one gene orthology between the human and mouse. When lineage-specific gene duplication occurs and paralogous genes share a certain degree of functional redundancy, knockout mice may not provide accurate functional information on human genes. Angiogenin is a small protein that stimulates blood-vessel growth and promotes tumor development. Humans and related primates only have one angiogenin gene, while mice have three paralogous genes. This makes it difficult to generate angiogenin-knockout mice and even more difficult to interpret the genotype-phenotype relation from such animals should they be generated. We here show that in the douc langur (Pygathrix nemaeus), an Asian leaf-eating colobine monkey, the single-copy angiogenin gene has a one-nucleotide deletion in the sixth codon of the mature peptide, generating a premature stop codon. This nucleotide deletion is found in five unrelated individuals sequenced, and therefore is likely to have been fixed in the species. Five colobine species that are closely related to the douc langur have intact angiogenin genes, suggesting that the pseudogenization event was recent and unique to the douc langur lineage. This natural knockout experiment suggests that primate angiogenin is dispensable even in the wild. Further physiological studies of douc largurs may offer additional information on the role of this cancer-related gene in normal physiology of primates, including humans. Our findings also provide a strong case for the importance of evolutionary analysis in biomedical studies of gene functions. (C) 2003 Elsevier Science B.V. All rights reserved.

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Pancreatic RNase genes implicated in the adaptation of the colobine monkeys to leaf eating have long intrigued evolutionary biologists since the identification of a duplicated RNASE1 gene with enhanced digestive efficiencies in Pygathrix nemaeus. The recent emergence of two contrasting hypotheses, that is, independent duplication and one-duplication event hypotheses, make it into focus again. Current understanding of Colobine RNASE1 gene evolution of colobine monkeys largely depends on the analyses of few colobine species. The present study with more intensive taxonomic and character sampling not only provides a clearer picture of Colobine RNASE1 gene evolution but also allows to have a more thorough understanding about the molecular basis underlying the adaptation of Colobinae to the unique leaf-feeding lifestyle. The present broader and detailed phylogenetic analyses yielded two important findings: 1) All trees based on the analyses of coding, noncoding, and both regions provided consistent evidence, indicating RNASE1 duplication occurred after Asian and African colobines speciation, that is, independent duplication hypothesis; 2) No obvious evidence of gene conversion in RNASE1 gene was found, favoring independent evolution of Colobine RNASE1 gene duplicates. The conclusion drawn from previous studies that gene conversion has played a significant role in the evolution of Colobine RNASE1 was not supported. Our selective constraint analyses also provided interesting insights, with significant evidence of positive selection detected on ancestor lineages leading to duplicated gene copies. The identification of a handful of new adaptive sites and amino acid changes that have not been characterized previously also provide a necessary foundation for further experimental investigations of RNASE1 functional evolution in Colobinae.

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Hybridization is an important biological phenomenon that can be used to understand the evolutionary process of speciation of plants and their associated pests and diseases. Interactions between hybrid plants and the herbivores of the parental taxa may be used to elucidate the various cues being used by the pests for host location or other processes. The chemical composition of plants, and their physical foliar attributes, including leaf thickness, trichome density, moisture content and specific leaf weight were compared between allopatric pure and commercial hybrid species of Corymbia, an important subtropical hardwood taxon. The leaf-eating beetle Paropsis atomaria, to which the pure taxa represented host (C. citriodora subsp. variegata) and non-host (C. torelliana) plants, was used to examine patterns of herbivory in relation to these traits. Hybrid physical foliar traits, chemical profiles, and field and laboratory beetle feeding preference, while showing some variability, were generally intermediate to those exhibited by parent taxa, thus suggesting an additive inheritance pattern. The hybrid susceptibility hypothesis was not supported by our field or laboratory studies, and there was no strong relationship between adult preference and larval performance. The most-preferred adult host was the sympatric taxon, although this species supported the lowest larval survival, while the hybrid produced significantly smaller pupae than the pure species. The results are discussed in relation to plant chemistry and physical characteristics. The findings suggest a chemical basis for host selection behavior and indicate that it may be possible to select for resistance to this insect pest in these commercially important hardwood trees.

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To obtain a more complete understanding of the evolutionary history of the leaf-eating monkeys we have examined the mitochondrial genome sequence of two African and six Asian colobines. Although taxonomists have proposed grouping the "odd-nosed" colobines

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In order to understand how mandibular structure differs among the Chinese cercopithecoids (Rhinopithecus, Trachypithecus and Macaca), particularly the uniqueness of the snub-nosed monkeys (Rhinopithecus), we analysed ten mandibular measurements by principal components analysis (PCA), and examined scaling patterns. The results provided by the PCA illustrated differences due to size among the cercopithecoids and the relationship between colobines (Trachypithecus and Rhinopithecus) and cercopithecines, in which macaques (Macaca) are included. Allometric analysis indicated that, biomechanically, there is not a marked difference between macaques and leaf-eating monkeys. This may be associated with the fact that both share some similar ecology and niches in south and southwest China. The snub-nosed monkeys exhibit a significantly more robust mandible, evident in the symphysis, corpus, condyle, and masticatory momentum arm. This supports the hypothesis, based on the study of dental structure, that Rhinopithecus is a unique group in Asian Old World monkeys (OWMs) and has developed some unique characteristics in order to adapt to the tough food available in the severe cold climate of the Plateaux of Qinghai-Tibet, Yun-Gui and Qingling in China.

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Fatty acids in milk reflect the interplay between species-specific physiological mechanisms and maternal diet. Anthropoid primates (apes, Old and New World monkeys) vary in patterns of growth and development and dietary strategies. Milk fatty acid profiles also are predicted to vary widely. This study investigates milk fatty acid composition of five wild anthropoids (Alouatta palliata, Callithrix jacchus, Gorilla beringei beringei, Leontopithecus rosalia, Macaca sinica) to test the null hypothesis of a generalized anthropoid milk fatty acid composition. Milk from New and Old World monkeys had significantly more 8:0 and 10:0 than milk from apes. The leaf eating species G. b. beringei and A. paliatta had a significantly higher proportion of milk 18:3n-3, a fatty acid found primarily in plant lipids. Mean percent composition of 22:6n-3 was significantly different among monkeys and apes, but was similar to the lowest reported values for human milk. Mountain gorillas were unique among anthropoids in the high proportion of milk 20:4n-6. This seems to be unrelated to requirements of a larger brain and may instead reflect species-specific metabolic processes or an unknown source of this fatty acid in the mountain gorilla diet.

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The production of sound, clean fruit is unquestionably one of the major problems facing the modern fruit grower. Culture may be neglected and pruning delayed for a time but the omission of sprays for even a single season demonstrates their absolute necessity. This applies equally to the commercial grower and to the farmer or gardener who has only a few trees. Spray materials, equipment, management, schedules, insect pests and orchard diseases are discussed in this 1928 extension circular.

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This report presents the process and outcomes of a five year project, which employed genetics and breeding approach for integrating disease resistance,agronomy and quality traits that enhances sustainable productivity improvement in sweet corn production. The report outlines a molecular markers based approach to introgress quantitative traits loci that are believed to contribute to resistance to downy mildew, a potentially devastating disease that threatens sweet corn and other similar crops. It also details the approach followed to integrate resistances for other major diseases such as southern rust (caused by Puccinia polysora Underw), Northern Corn Leaf Blight (Exserohilum turcicum) with improved agronomy and eating quality. The report explains the importance of heterosis (hybrid vigour) and combining ability in the development of useful sweet corn hybrids. It also explains the relevance of parental performance to predict its breeding value and the performance of its hybrids.

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Blue Leaf es un proyecto de emprendimiento que consiste en la elaboración y venta directa de bebidas naturales a base de frutas a través de un food truck en la ciudad de Bogotá. Tras revisar algunas tendencias actuales como la cultura Fitness y el Juicing, y tras identificar un problema sobre los hábitos de alimentación desordenados que llevan muchas personas, nace Blue Leaf como una alternativa de alimentación saludable, natural, práctica y diferente. El negocio contará inicialmente con un portafolio de 12 bebidas divididas en tres categorías. Primero, las bebidas alimenticias cuentan con altos contenidos nutricionales y sirven como fuente de alimento práctico y saludable; segundo, las bebidas funcionales, están diseñadas para ofrecer beneficios específicos de salud como desintoxicar, ayudar a bajar de peso o fortalecer las defensas; por último, las bebidas fuente de energía, cuentan con altos niveles de vitaminas y minerales que le permiten a los consumidores recargar energías rápidamente y continuar con sus actividades diarias. Adicionalmente, Blue Leaf ofrecerá la oportunidad a los consumidores de hacer su propia bebida, dándoles la posibilidad de elegir de entre más de 50 ingredientes entre bases, frutas, verduras, hierbas, semillas, adiciones y endulzantes. El proyecto es liderado por Paola Higuera Rodríguez y David Santiago Soto, ambos estudiantes de la Escuela de Administración de la Universidad del Rosario

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Emotional eating has been identified as a factor that promotes the development and maintenance of obesity and hinders its treatment. This study investigated the relationship between unsatisfied basic needs and emotional eating, including the mediating factors of self-esteem and coping strategies. The results from a survey of 136 obese individuals indicated support for a significant relationship between basic need satisfaction and emotional eating, with a mediating effect of negative coping strategies. These findings extend previous research and provide guidance on how to help individuals who engage in emotional eating by focusing on developing more adaptive coping strategies.

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The elaborated intrusion (EI) theory of desire (Kavanagh, Andrade, & May, 2005) attributes the motivational force of cravings to cognitive elaboration, including imagery, of apparently spontaneous thoughts that intrude into awareness. We report a questionnaire study in which respondents rated a craving for food or drink. Questionnaire items derived from EI theory formed a single factor alongside factors for anticipated reward/relief, resistance, and opportunity. In a multiple regression predicting strength of craving, the first three factors accounted for 36% of the variance. Opportunity did not enter the model. In a second study, the difference between individuals' strong and weak cravings to take part in a sporting activity was shown to be related to visual, auditory, and general imagery, and to anticipated reward or relief from engaging in the activity. Implications for treatment of craving-related disorders are discussed in the light of these results and of other research indicating that interference with imagery can reduce the strength of craving.