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The emergence and rapid spread of methicillin-resistant Staphylococcus aureus (MRSA) critically requires alternative therapeutic options. New antibacterial drugs and strategies are urgently needed to combat MRSA-associated infections. Here, we investigated the antibacterial activity of flavones from Morus alba and the potential mode of action against MRSA. Kuwanon G, kuwanon H, mulberrin, and morusin displayed high efficiency in killing diverse MRSA isolates. On the basis of structure–activity analysis, the cyclohexene-phenyl ketones and isopentenyl groups were critical to increase the membrane permeability and to dissipate the proton motive force. Meanwhile, mechanistic studies further showed that kuwanon G displayed rapid bactericidal activity in vitrowith difficulty in developing drug resistance. Kuwanon G targeted phosphatidylglycerol and cardiolipin in the cytoplasmic membrane through the formation of hydrogen bonds and electrostatic interactions. Additionally, kuwanon G promoted wound healing in a mouse model of MRSA skin infection. In summary, these results indicate that flavones are promising lead compounds to treat MRSA-associated infections through disrupting the proton motive force and membrane permeability.

Reliable multicast applications such as software distribution, data distribution and replication and mailing list delivery, etc.[1] are getting more and more interests from network and service providers. The conventional error/loss recovery schemes are not efficient when they are applied to multicast scenarios in wireless networks. The reason lies in the unreliable wireless channel, the limited wireless bandwidth and resource, the battery powered wireless devices, and others. To have an effective error/loss recovery scheme for reliable multicast in wireless networks, we advocate a new communication architecture. It is referred to as cellular controlled peer-topeer network [2], where the mobile devices communicate directly with each other to perform cooperative retransmissions using their short-range communication capabilities in addition to their cellular links. Based on the cooperative architecture a novel retransmission scheme is proposed exploiting the shortrange retransmission in this paper. The state of the art, the non-cooperative error recovery schemes (e.g., ARQ, Layered FEC and Integrated FEC II) and the proposed scheme are compared with each other in terms of energy consumption to show the benefit of the newly introduced scheme.

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