Metabolic and Chaperone Gene Loss Marks the Origin of Animals: Evidence for Hsp104 and Hsp78 Sharing Mitochondrial Clients

The evolution of animals involved acquisition of an emergent gene repertoire for gastrulation. Whether loss of genes also co-evolved with this developmental reprogramming has not yet been addressed. Here, we identify twenty-four genetic functions that are retained in fungi and choanoflagellates but undetectable in animals. These lost genes encode: (i) sixteen distinct biosynthetic functions; (ii) the two ancestral eukaryotic ClpB disaggregases, Hsp78 and Hsp104, which function in the mitochondria and cytosol, respectively; and (iii) six other assorted functions. We present computational and experimental data that are consistent with a joint function for the differentially localized ClpB disaggregases, and with the possibility of a shared client/chaperone relationship between the mitochondrial Fe/S homoaconitase encoded by the lost LYS4 gene and the two ClpBs. Our analyses lead to the hypothesis that the evolution of gastrulation-based multicellularity in animals led to efficient extraction of nutrients from dietary sources, loss of natural selection for maintenance of energetically expensive biosynthetic pathways, and subsequent loss of their attendant ClpB chaperones.Comment: This is a reformatted version from the recent official publication in PLoS ONE (2015). This version differs substantially from first three arXiV versions. This version uses a fixed-width font for DNA sequences as was done in the earlier arXiv versions but which is missing in the official PLoS ONE publication. The title has also been shortened slightly from the official publicatio

Analyzing inter-organizational systems from a power and interest perspective

Inter-organizational systems (IOS) are ICT-based systems that enable organizations to share information and to electronically conduct business across organizational boundaries. Especially since the increasing availability of the Internet, there have been less technological barriers to implement IOS. However, that does not imply that IOS-possibilities are implemented successfully in all occasions: other barriers may remain. Innovation is not only a technical process of ?solving problems?, it also involves economic and political processes in which interests are articulated, alliances are built and outcomes are struggled over. To explore this observation, this paper presents a model that helps to describe and analyze IOS from a power and interest perspective of multiple parties. To illustrate this model, eight case studies of IOS are discussed, of which two in more depth. After that, we will put the findings of the analysis in a broader perspective. The paper concludes with the assertion that the scope for the design of an effective IOS depends on a combination of technical, economic and social

Microphase separation in thin block copolymer films: a weak segregation mean-field approach

In this paper we consider thin films of AB block copolymer melts confined between two parallel plates. The plates are identical and may have a preference for one of the monomer types over the other. The system is characterized by four parameters: the Flory-Huggins chi-parameter, the fraction f of A-monomers in the block copolymer molecules, the film thickness d, and a parameter h quantifying the preference of the plates for the monomers of type A. In certain regions of parameter space, the film will be microphase separated. Various structures have been observed experimentally, each of them characterized by a certain symmetry, orientation, and periodicity. We study the system theoretically using the weak segregation approximation to mean field theory. We restrict our analysis to the region of the parameter space where the film thickness d is close to a small multiple of the natural periodicity. We will present our results in the form of phase diagrams in which the absolute value of the deviation of the film thickness from a multiple of the bulk periodicity is placed along the horizontal axis, and the chi-parameter is placed along the vertical axis; both axes are rescaled with a factor which depends on the A-monomer fraction f. We present a series of such phase diagrams for increasing values of the surface affinity for the A-monomers. We find that if the film thickness is almost commensurate with the bulk periodicity, parallel orientations of the structures are favoured over perpendicular orientations. We also predict that on increasing the surface affinity, the region of stability of the bcc phase shrinks.Comment: 35 pages, 20 figure

Realtime system control by means of path expressions

A high-level, algebraic programming method for the online control of actions in a real-time, parallel processing environment is described. The method is based on the interaction of path expressions. On the basis of a set of path expressions, evocation of actions can be controlled in real-time in a fully automated way. It is shown how intelligent system behavior can be obtained by a combination of rules given as path expressions. Each of these rules specifies some partial behavior to which the system must comply. The control system operates as a rule-based action planning system that works online in an asynchronous environment. The development of the prototype system PBOS (Path Based Operating System) has demonstrated that path expression specification naturally integrates with a real-time, multitasking control syste

Energy from streaming current and potential

It is investigated how much energy can be delivered by a streaming current source. A streaming current and subsequent streaming potential originate when double layer charge is transported by hydrodynamic flow. Theory and a network model of such a source is presented and initial experimental results are given, showing a supplied power of 20 nW obtained by a pressure difference of 1 atm over a glass porous plug, using a 1-mM KCl solution. It is indicated how the rather low mechanical-to-electrical energy conversion efficiency can be increased