The unicellular alga Chlamydomonas reinhardtii and the bacterium Pseudomonas protegens serve as a model to study the interactions between photosynthetic and heterotrophic microorganisms. P. protegens secretes the cyclic lipopeptide orfamide A that interferes with cytosolic Ca 2+ homeostasis in C. reinhardtii resulting in deflagellation of the algal cells. Here, we studied the roles of additional secondary metabolites secreted by P. protegens using individual compounds and co-cultivation of algae with bacterial mutants. Rhizoxin S2, pyrrolnitrin, pyoluteorin, 2,4-diacetylphloroglucinol (DAPG) and orfamide A all induce changes in cell morphology and inhibit the growth of C. reinhardtii. Rhizoxin S2 exerts the strongest growth inhibition, and its action depends on the spatial structure of the environment (agar versus liquid culture). Algal motility is unaffected by rhizoxin S2 and is most potently inhibited by orfamide A (IC 50 = 4.1 μM). Pyrrolnitrin and pyoluteorin both interfere with algal cytosolic Ca 2+ homeostasis and motility whereas high concentrations of DAPG immobilize C. reinhardtii without deflagellation or disturbance of Ca 2+ homeostasis. Co-cultivation with a regulatory mutant of bacterial secondary metabolism (ΔgacA) promotes algal growth under spatially structured conditions. Our results reveal how a single soil bacterium uses an arsenal of secreted antialgal compounds with complementary and partially overlapping activities.
The need to improve the U.S. poverty measure has received renewed attention as state and local governments have initiated antipoverty efforts and wish to judge their effect. This paper describes the New York City Center for Economic Opportunity's implementation of the National Academy of Sciences' recommendations for measuring poverty. The center's decision to use the Census Bureau's American Community Survey as its principal data source created the project's central challenge; many of the items needed to construct the academy's measure of resources are not included in the survey and needed to be estimated through a variety of methods. The resultant measure creates a higher poverty rate and a demographic profile of the poor that is quite different from that generated by the official measure. The paper Kenneth Couch, Guest Editor Professional PracticeThis is an unusual Professional Practice in a couple of respects. For example, this Professional Practice has a guest editor, Kenneth Couch, from the University of Connecticut. Ken and I, plus some of the authors in this section, were participants in a conference on measuring poverty, social exclusion, and well-being that was held at the Organization for Economic Cooperation and Development, held in Paris, in March 2009. Also, unlike most Professional Practice publications, this one focuses on measurement of a key construct for policy analysts, public managers, and policy makers-poverty. So essential is this construct that I felt it was important to relay the European experiences and thinking on these issues and its relevance for the current poverty measurement in the U.S. I hope you enjoy this section as much as I did.Maureen A. Pirog, Editor-in-Chief, JPAM / Professional Practice concludes with observations about these differences and how this new picture of poverty has begun to influence policymaking in New York City. © 2010 by the Association for Public Policy Analysis and Management.The inadequacies of the official U.S. poverty measure are well known to social scientists. In 2006 they became vividly clear to New York City policymakers. Mayor Michael Bloomberg convened a Commission for Economic Opportunity and asked its members to develop new ideas for addressing poverty in the city. In the course of their work the commissioners became frustrated with how little the current poverty measure could tell them about either the degree of economic deprivation in the city or the effect of programs intended to alleviate it. In its report to the mayor, the commission urged that, in addition to new antipoverty programs, New York City should develop a better method to count the poor (Commission for Economic Opportunity, 2006). Mayor Bloomberg embraced the suggestion and poverty measurement has become part of the mission of the organization created to implement the commission's recommendations: the New York City Center for Economic Opportunity (CEO).This paper summarizes CEO's initial effort to apply the National Academy of Sciences' (NAS) recommendations for measurin...
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