Mechanosensitive (MS) channels are universal cellular membrane pores. Bacterial MS channels, as typified by MS channel of small conductance (MscS) from Escherichia coli (EcMscS), release osmolytes under hypoosmotic conditions. MS channels are known to be ion selective to different extents, but the underlying mechanism remains poorly understood. Here we identify an anion-selective MscS channel from Thermoanaerobacter tengcongensis (TtMscS). The structure of TtMscS closely resembles that of EcMscS, but it lacks the large cytoplasmic equatorial portals found in EcMscS. In contrast, the cytoplasmic pore formed by the C-terminal β-barrel of TtMscS is larger than that of EcMscS and has a strikingly different pattern of electrostatic surface potential. Swapping the β-barrel region between TtMscS and EcMscS partially switches the ion selectivity. Our study defines the role of the β-barrel in the ion selection of an anion-selective MscS channel and provides a structural basis for understanding the ion selectivity of MscS channels.crystal structure | anion selection | cytoplasmic region | electrophysiology | single channel recording

Insufficient clinical trial data were available to prove the efficacy of acupuncture for migraine prophylaxis. A multicenter, double-dummy, single-blinded, randomized controlled clinical trial was conducted at the outpatient departments of acupuncture at 5 hospitals in China to evaluate the effectiveness of acupuncture. A total of 140 patients with migraine without aura were recruited and assigned randomly to 2 different groups: the acupuncture group treated with verum acupuncture plus placebo and the control group treated with sham acupuncture plus flunarizine. Treated by acupuncture 3 times per week and drugs every night, patients from both groups were evaluated at week 0 (baseline), week 4, and week 16. The primary outcome was measured by the proportion of responders (defined as the proportion of patients with a reduction of migraine days by at least 50%). The secondary outcome measures included the number of migraine days, visual analogue scale (VAS, 0 to 10 cm) for pain, as well as the physical and mental component summary scores of the 36-item short-form health survey (SF-36). The patients in the acupuncture group had better responder rates and fewer migraine days compared with the control group (P<.05), whereas there were no significant differences between the 2 groups in VAS scores and SF-36 physical and mental component summary scores (P>.05). The results suggested that acupuncture was more effective than flunarizine in decreasing days of migraine attacks, whereas no significantly differences were found between acupuncture and flunarizine in reduction of pain intensity and improvement of the quality of life.

Room temperature isothermal reversible spin crossover switching of [Fe(HB(pz))(bipy)] thin films is demonstrated. The magnetic oxide substrate locks the [Fe{HB(pz)}(bipy)] largely in a low spin state. With an X-ray fluence, excitation to a high spin state occurs, while relaxation back to low spin state is aided by alternating the substrate magnetization.