Promotion of oxidative phosphorylation by complex I-anchored carbonic anhydrases?

The mitochondrial NADH-dehydrogenase complex of the respiratory chain, known as complex I, includes a carbonic anhydrase (CA) module attached to its membrane arm on the matrix side in protozoans, algae, and plants. Its physiological role is so far unclear. Recent electron cryo-microscopy (cryo-EM) structures show that the CA module may directly provide protons for translocation across the inner mitochondrial membrane at complex I. CAs can have a central role in adjusting the proton concentration in the mitochondrial matrix. We suggest that CA anchoring in complex I represents the original configuration to secure oxidative phosphorylation (OXPHOS) in the context of early endosymbiosis. After development of ‘modern mitochondria’ with pronounced cristae structures, this anchoring became dispensable, but has been retained in protozoans, algae, and plants

Information Flow Analysis Based Security Checking of Health Service Composition Plans

In this paper, we present an approach to solve the problem of provably secure execution of semantic web service composition plans. The integrated components of this approach include our OWL-S service matchmaker, OWLSMX, the service composition planner, OWLS-XPlan, and the security checker module for formally verifying the compliance of the created composition plan to be executed with given data and service security policies using type-based information flow analysis. We demonstrate this approach by means of its application to a use case scenario of health service composition planning

Group Formation Among Peer-to-Peer Agents: Learning Group Characteristics

This paper examines the decentralized formation of groups within a peer-to-peer multi-agent system. More specifically, it frames group formation as a clustering problem, and examines how to determine cluster characteristics such as area and density in the absence of information about the entire data set, such as the number of points, the number of clusters, or the maximum distance between points, that are available to centralized clustering algorithms. We develop a method in which agents individually search for other agents with similar characteristics in a peer-to-peer manner. These agents group into small centrally controlled clusters which learn cluster parameters by examining and improving their internal composition over time. We show through simulation that this method allows us to find clusters of a wide variety of sizes without adjusting agent parameters

Fast Composition Planning of OWL-S Services and Application

In this paper, we present the implementation, evaluation, and application of our OWL-S service composition planner OWLS-XPlan. Medical services described in OWL-S 1.1 and ontologies are converted to initial state and goal descriptions in PDDL 2.1, which are then used by the fast heuristic FF planner XPlan for generating an execution complete composition plan. Results of experimental evaluation of XPlan shows its top performance compared with other selected AI planners. OWLS-XPlan is used in an agent based mobile e-Health system for emergency medical assistance planning tasks

WSMO-Lite and hRESTS: lightweight semantic annotations for Web services and RESTful APIs

Service-oriented computing has brought special attention to service description, especially in connection with semantic technologies. The expected proliferation of publicly accessible services can benefit greatly from tool support and automation, both of which are the focus of Semantic Web Service (SWS) frameworks that especially address service discovery, composition and execution. As the first SWS standard, in 2007 the World Wide Web Consortium produced a lightweight bottom-up specification called SAWSDL for adding semantic annotations to WSDL service descriptions. Building on SAWSDL, this article presents WSMO-Lite, a lightweight ontology of Web service semantics that distinguishes four semantic aspects of services: function, behavior, information model, and nonfunctional properties, which together form a basis for semantic automation. With the WSMO-Lite ontology, SAWSDL descriptions enable semantic automation beyond simple input/output matchmaking that is supported by SAWSDL itself. Further, to broaden the reach of WSMO-Lite and SAWSDL tools to the increasingly common RESTful services, the article adds hRESTS and MicroWSMO, two HTML microformats that mirror WSDL and SAWSDL in the documentation of RESTful services, enabling combining RESTful services with WSDL-based ones in a single semantic framework. To demonstrate the feasibility and versatility of this approach, the article presents common algorithms for Web service discovery and composition adapted to WSMO-Lite

Curious Negotiator

n negotiation the exchange of information is as important as the exchange of offers. The curious negotiator is a multiagent system with three types of agents. Two negotiation agents, each representing an individual, develop consecutive offers, supported by information, whilst requesting information from its opponent. A mediator agent, with experience of prior negotiations, suggests how the negotiation may develop. A failed negotiation is a missed opportunity. An observer agent analyses failures looking for new opportunities. The integration of negotiation theory and data mining enables the curious negotiator to discover and exploit negotiation opportunities. Trials will be conducted in electronic business

Cryo-EM structure of the respiratory I + III2 supercomplex from Arabidopsis thaliana at 2 Å resolution

Protein complexes of the mitochondrial respiratory chain assemble into respiratory supercomplexes. Here we present the high-resolution electron cryo-microscopy structure of the Arabidopsis respiratory supercomplex consisting of complex I and a complex III dimer, with a total of 68 protein subunits and numerous bound cofactors. A complex I-ferredoxin, subunit B14.7 and P9, a newly defined subunit of plant complex I, mediate supercomplex formation. The component complexes stabilize one another, enabling new detailed insights into their structure. We describe (1) an interrupted aqueous passage for proton translocation in the membrane arm of complex I; (2) a new coenzyme A within the carbonic anhydrase module of plant complex I defining a second catalytic centre; and (3) the water structure at the proton exit pathway of complex III2 with a co-purified ubiquinone in the QO site. We propose that the main role of the plant supercomplex is to stabilize its components in the membrane