Structural development of a type-1 ryanodine receptor (RyR1) Ca2+-release channel inhibitor guided by endoplasmic reticulum Ca2+ assay.

Type-1 ryanodine receptor (RyR1) is a calcium-release channel localized on sarcoplasmic reticulum (SR) of the skeletal muscle, and mediates muscle contraction by releasing Ca2+ from the SR. Genetic mutations of RyR1 are associated with skeletal muscle diseases such as malignant hyperthermia and central core diseases, in which over-activation of RyR1 causes leakage of Ca2+ from the SR. We recently developed an efficient high-throughput screening system based on the measurement of Ca2+ in endoplasmic reticulum, and used it to identify oxolinic acid (1) as a novel RyR1 channel inhibitor. Here, we designed and synthesized a series of quinolone derivatives based on 1 as a lead compound. Derivatives bearing a long alkyl chain at the nitrogen atom of the quinolone ring and having a suitable substituent at the 7-position of quinolone exhibited potent RyR1 channel-inhibitory activity. Among the synthesized compounds, 14h showed more potent activity than dantrolene, a known RyR1 inhibitor, and exhibited high RyR1 selectivity over RyR2 and RyR3. These compounds may be promising leads for clinically applicable RyR1 channel inhibitors.

High-Performance Organic Energy-Harvesting Devices and Modules for Self-Sustainable Power Generation under Ambient Indoor Lighting Environments.

Organic photovoltaics (OPVs) that perform more efficiently under artificial indoor lighting conditions than they do under sunlight are attracting growing interest as they can potentially serve as ambient energy harvesters for powering low-power electronics and portable devices for the Internet of Things. Herein, solution-processed small-molecule OPVs are demonstrated to exhibit high power conversion efficiencies exceeding 16% under white LED illumination, delivering high output power densities of up to 12.4 and 65.3 µW cm-2 at 200 and 1000 lx, respectively. Increasing the open-circuit voltage ( Voc) of OPVs is a critical factor for achieving higher indoor photovoltaic performance. Toward real applications, this small-molecule OPV system is adopted to fabricate six series-connected modules with an active area of ∼10 cm2 that are capable of generating a high output power surpassing 100 µW and a high Voc of over 4.2 V even under dimly lit indoor conditions of 200 lx. These results indicate that OPVs are promising as indoor electric power sources for self-sustainable electronic devices.

Oligothiophene-Indandione-Linked Narrow-Band Gap Molecules: Impact of π-Conjugated Chain Length on Photovoltaic Performance.

Solution-processed organic solar cells (OSCs) based on narrow-band gap small molecules hold great promise as next-generation energy-converting devices. In this paper, we focus on a family of A-π-D-π-A-type small molecules, namely, BDT- nT-ID ( n = 1-4) oligomers, consisting of benzo[1,2- b:4,5- b']dithiophene (BDT) as the central electron-donating (D) core, 1,3-indandione (ID) as the terminal electron-accepting (A) units, and two regioregular oligo(3-hexylthiophene)s ( nT) with different numbers of thiophene rings as the π-bridging units, and elucidate their structure-property-function relationships. The effects of the length of the π-bridging nT units on the optical absorption, thermal behavior, morphology, hole mobility, and OSC performance were systematically investigated. All oligomers exhibited broad and intense visible photoabsorption in the 400-700 nm range. The photovoltaic performances of bulk heterojunction OSCs based on BDT- nT-IDs as donors and a fullerene derivative as an acceptor were studied. Among these oligomers, BDT-2T-ID, incorporating bithiophene as the π-bridging units, showed better photovoltaic performance with a maximum power conversion efficiency as high as 6.9% under AM 1.5G illumination without using solvent additives or postdeposition treatments. These favorable properties originated from the well-developed interpenetrating network morphology of BDT-2T-ID, with larger domain sizes in the photoactive layer. Even though all oligomers have the same A-D-A main backbone, structural modulation of the π-bridging nT length was found to impact their self-organization and nanostructure formation in the solid state, as well as the corresponding OSC device performance.

Reversible photoinduced change in molecular ordering of diarylethene derivatives at a solution-HOPG interface.

A diarylethene-pyrene diad and a diarylethene-pyrene-diarylethene triad were synthesized to investigate the photoinduced two-dimensional ordering change at a solution-HOPG interface. The molecular arrangements were detected by STM. The different photochromic isomers showed different orderings reflecting the differences in their molecular structures. For the diarylethene-pyrene-diarylethene triad, a new ordering appeared upon irradiation with UV light and returned to the original ordering upon subsequent irradiation with visible light. The new arrangement was assigned to the ordering of the closed-closed isomers based on the images of the isolated open- and closed-isomers. The relationship between the nature of the two-dimensional ordering and the molecular structure is discussed.

Retrotransposon-mediated restoration of Chlorella telomeres: accumulation of Zepp retrotransposons at termini of newly formed minichromosomes.

To elucidate the contribution of LINE-like retrotransposon Zepp elements to the formation and maintenance of chromosomal telomeres, newly formed minichromosomes in irradiated Chlorella vulgaris cells were isolated and structurally characterized. A minichromosome (miniV4) of approximately 700 kb in size contained a Zepp cluster taking the place of the telomeric repeats on one terminus, whereas the other end of this chromosome consisted of canonical telomeric repeats. The Zepp copies in this cluster were in a tandem array with their poly(A) tails towards the centromere. Another minichromosome Y32 ( approximately 400 kb in size) was shown to have several copies of Zepp elements on both termini. On the right arm terminus, two copies of Zepp were found in a tandem array with poly(A) tracts facing towards the chromosomal end. The poly(A) tail and the 3'-end of approximately 400 bp of the distal copy were replaced by the telomeric repeats. On the 5'-side of the proximal copy was another Zepp element in the reverse orientation. These newly formed telomeric structures are very similar to those previously found in the left arm of chromosome I and the terminus of an unidentified chromosome and support the model of Zepp-mediated restoration and maintenance of Chlorella telomeres.