Stress-induced Hfq-binding small RNAs of Escherichia coli, SgrS and RyhB, down-regulate the expression of target mRNAs through base-pairing. These small RNAs form ribonucleoprotein complexes with Hfq and RNase E. The regulatory outcomes of the RNase E͞Hfq͞small RNA-containing ribonucleoprotein complex (sRNP) are rapid degradation of target mRNAs and translational inhibition. Here, we ask to what extent the sRNP-mediated mRNA destabilization contributes to the overall silencing of target genes by using strains in which the rapid degradation of mRNA no longer occurs. We demonstrate that translational repression occurs in the absence of sRNP-mediated mRNA destabilization. We conclude that translational repression is sufficient for gene silencing by sRNP. One possible physiological role of mRNA degradation mediated by sRNP is to rid the cell of translationally inactive mRNAs, making gene silencing irreversible.bacterial small RNA-containing ribonucleoprotein complex ͉ Hfq ͉ mRNA degradation ͉ RNase E ͉ glucose transporter

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When multi-agent systems explore in actual environments, it is difficult to manage agents centralizedly from outside due to communicable range. This paper proposes a maze exploration algorithm for distributed control system considering communicable range of agents. In proposed algorithm, agents share information each other within communicable range and then each agent detects deadlocks generating a wait-for graph from the shared information. Sharing cycle of wait-for graphs enables agents to take over the explorations each other and resolve deadlocks. This paper verifies the effectiveness of the proposed deadlock resolution algorithm via numerical experiments about some of communicable ranges and numbers of agents of exploration system. The simulation results show the influence of the proposed deadlock resolution algorithm on the efficiency of exploration and the path length of agents. The simulation results also show the relationship between the communicable range, the number of agents of exploration system and the failure probability of exploration.

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In cooperative maze exploration via multi-agent systems, deadlock resolution methods influence exploration efficiency. This paper evaluates the relation between communication protocols and exploration efficiency. This paper proposes three communication protocols for deadlock resolution on maze exploration via distributed collaborative control system considering communicable range of agents. The agents share different information depending on the communication protocols for deadlock resolution. The transmission route of the information is affected by the communication protocols for deadlock resolution. The first result is to show a relationship between communicable range and performance of deadlock detection and communication load as the characteristics of each proposed communication protocols. The second result is to derive the relation between flow quantity and density for some network structure. Using the two results we evaluate influence of communication protocols on exploration efficiency.