Evolution of virulence in opportunistic pathogens: generalism, plasticity, and control

Standard virulence evolution theory assumes that virulence factors are maintained because they aid parasitic exploitation, increasing growth within and/or transmission between hosts. An increasing number of studies now demonstrate that many opportunistic pathogens (OPs) do not conform to these assumptions, with virulence factors maintained instead because of advantages in non-parasitic contexts. Here we review virulence evolution theory in the context of OPs and highlight the importance of incorporating environments outside a focal virulence site. We illustrate that virulence selection is constrained by correlations between these external and focal settings and pinpoint drivers of key environmental correlations, with a focus on generalist strategies and phenotypic plasticity. We end with a summary of key theoretical and empirical challenges to be met for a fuller understanding of OPs

Synergy and Group Size in Microbial Cooperation

Microbes produce many molecules that are important for their growth and development, and the consumption of these secretions by nonproducers has recently become an important paradigm in microbial social evolution. Though the production of these public goods molecules has been studied intensely, little is known of how the benefits accrued and costs incurred depend on the quantity of public good molecules produced. We focus here on the relationship between the shape of the benefit curve and cellular density with a model assuming three types of benefit functions: diminishing, accelerating, and sigmoidal (accelerating then diminishing). We classify the latter two as being synergistic and argue that sigmoidal curves are common in microbial systems. Synergistic benefit curves interact with group sizes to give very different expected evolutionary dynamics. In particular, we show that whether or not and to what extent microbes evolve to produce public goods depends strongly on group size. We show that synergy can create an “evolutionary trap” which can stymie the establishment and maintenance of cooperation. By allowing density dependent regulation of production (quorum sensing), we show how this trap may be avoided. We discuss the implications of our results for experimental design

Photoelectrochemical fabrication of spectroscopic diffraction gratings, phase 2

This program was directed toward the production of Echelle diffraction gratings by a light-driven, electrochemical etching technique (photoelectrochemical etching). Etching is carried out in single crystal materials, and the differential rate of etching of the different crystallographic planes used to define the groove profiles. Etching of V-groove profiles was first discovered by us during the first phase of this project, which was initially conceived as a general exploration of photoelectrochemical etching techniques for grating fabrication. This highly controllable V-groove etching process was considered to be of high significance for producing low pitch Echelles, and provided the basis for a more extensive Phase 2 investigation

Present status of perch fishery resources in India and its prospects

The perch resources and fisheries In India have been dealt with. As seen from the statewise perch production during 1969-19Q1, on an average 27,184 tonnes of parches were landed in India with fluctuation from 12,865 In 1969 to 49,312 in 1978. The gearwise and statewise perch production from 1982-83 to 1984-85 indicates that the mechanised units contributed 72.4 % and nonmechanised 27.6 %. Among mechanised units, the trawlers have landed the major portion of the catch (68 4 % ) . The State wise species composition of perch landings indicate that the threadtin breams formed more than 50% of the catch- During 1982-83 and 1S83-84. the perch production of Tamil Nadu was higher than all other states whereas during 1984 85, Kerala was the first in perch production followed by Andhrapradesh and Tamil Nadu- The different groups of perches landed by trawl and gill net units at different important landing centres on the east and west coast of Indian show that in all the centres the catch rates of trawlers were higher. The higher catch rate in trawl net operations In Sasoons Dock and New ferry Wharf was due to voyage fishing for more than a da

Strengthening the Foundations of the Accountability Profession

Article discusses the conceptual foundations of the accountability profession in government. The role of the Academy for Government Accountability in strengthening the accountability profession and advancing research and education initiatives in government financial management is described. The author suggests that government accountability needs to be about stewardship, transparency, accountability and citizen-centric government