92 research outputs found

    Comparative genomics reveals diversity among xanthomonads infecting tomato and pepper

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    <p>Abstract</p> <p>Background</p> <p>Bacterial spot of tomato and pepper is caused by four <it>Xanthomonas </it>species and is a major plant disease in warm humid climates. The four species are distinct from each other based on physiological and molecular characteristics. The genome sequence of strain 85-10, a member of one of the species, <it>Xanthomonas euvesicatoria </it>(<it>Xcv</it>) has been previously reported. To determine the relationship of the four species at the genome level and to investigate the molecular basis of their virulence and differing host ranges, draft genomic sequences of members of the other three species were determined and compared to strain 85-10.</p> <p>Results</p> <p>We sequenced the genomes of <it>X. vesicatoria </it>(<it>Xv</it>) strain 1111 (ATCC 35937), <it>X. perforans </it>(<it>Xp</it>) strain 91-118 and <it>X. gardneri </it>(<it>Xg</it>) strain 101 (ATCC 19865). The genomes were compared with each other and with the previously sequenced <it>Xcv </it>strain 85-10. In addition, the molecular features were predicted that may be required for pathogenicity including the type III secretion apparatus, type III effectors, other secretion systems, quorum sensing systems, adhesins, extracellular polysaccharide, and lipopolysaccharide determinants. Several novel type III effectors from <it>Xg </it>strain 101 and <it>Xv </it>strain 1111 genomes were computationally identified and their translocation was validated using a reporter gene assay. A homolog to Ax21, the elicitor of XA21-mediated resistance in rice, and a functional Ax21 sulfation system were identified in <it>Xcv</it>. Genes encoding proteins with functions mediated by type II and type IV secretion systems have also been compared, including enzymes involved in cell wall deconstruction, as contributors to pathogenicity.</p> <p>Conclusions</p> <p>Comparative genomic analyses revealed considerable diversity among bacterial spot pathogens, providing new insights into differences and similarities that may explain the diverse nature of these strains. Genes specific to pepper pathogens, such as the O-antigen of the lipopolysaccharide cluster, and genes unique to individual strains, such as novel type III effectors and bacteriocin genes, have been identified providing new clues for our understanding of pathogen virulence, aggressiveness, and host preference. These analyses will aid in efforts towards breeding for broad and durable resistance in economically important tomato and pepper cultivars.</p

    Social change and the family: Comparative perspectives from the west, China, and South Asia

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    This paper examines the influence of social and economic change on family structure and relationships: How do such economic and social transformations as industrialization, urbanization, demographic change, the expansion of education, and the long-term growth of income influence the family? We take a comparative and historical approach, reviewing the experiences of three major sociocultural regions: the West, China, and South Asia. Many of the changes that have occurred in family life have been remarkably similar in the three settings—the separation of the workplace from the home, increased training of children in nonfamilial institutions, the development of living arrangements outside the family household, increased access of children to financial and other productive resources, and increased participation by children in the selection of a mate. While the similarities of family change in diverse cultural settings are striking, specific aspects of change have varied across settings because of significant pre-existing differences in family structure, residential patterns of marriage, autonomy of children, and the role of marriage within kinship systems.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45661/1/11206_2005_Article_BF01124383.pd

    Bangladesh and the Crises of Pakistan

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    The cyclonic fury with which the Pakistan Amy struck against the people of East Bengal exactly two years to the day on which the regime of President Ayub Khan had fallen and General Yahya Khan assumed power under Martial Law, marked a new stage in the deepening crisis of Pakistan. It is a crisis of national identity. It is also a crisis of the challenges which are being posed by the rising democratic forces in the country to the ruling bureaucratic-military oligarchy

    Imperialism Old And New

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    "Imperialism is the eve of the socialist revolution," wrote Lenin whilst revolutionary hearts were still warm with the apocalyptic vision of the social transformation that was about to take place following the disintegration of moribund capitalism. Monopoly capitalism was in the last throes of its general crisis; imperialism was the highest stage of its development. National liberation movements in colonial territories were an important part of the revolutionary process, for they undermined the positions of imperialism and intensified its contradictions

    India and the Colonial Mode of Production

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    Important issues have been raised by Indian Marxist agricultural economists in a debate about 'The Mode of Production in Indian Agriculture'.' That debate is taking place in the context of far-reaching changes that have taken place in Indian agriculture in recent years; changes that were once celebrated as 'The Green Revolution'. Today, its conservative authors as well as its radical critics are compelled, by the force of the contradictions in rural class relations (as well as in the economy as a whole) that have been brought to the surface as a consequence, to move beyond the limits of justification or condemnation, to analyse and assess the nature and significance of the structural changes that have been brought about

    Colonial Social Formations: The Indian Case

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    Peasants And Revolution

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    "In colonial countries the peasants alone are revolutionary, for they have nothing to lose and everything to gain. The starving peasant, outside the class system, is the first among the exploited to discover that only violence pays. For him there is no compromise, no possible coming to terms. . . .". That view of the revolutionary potentiality of the peasantry was expressed by Frantz Fanon, ideologue of the Algerian revolution. From time to time, throughout the centuries, the peasant has indeed risen in rebellion against his oppressors. But history is also replete with examples of peasantry which has borne silently and for long periods extremes of exploitation and oppression. At the same time occasional outbreaks of peasant revolt do raise the question of the conditions in which the peasant becomes revolutionary
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