Order-of-magnitude enhancement in photocurrent generation of Synechocystis sp. PCC 6803 by outer membrane deprivation.

Biophotovoltaics (BPV) generates electricity from reducing equivalent(s) produced by photosynthetic organisms by exploiting a phenomenon called extracellular electron transfer (EET), where reducing equivalent(s) is transferred to external electron acceptors. Although cyanobacteria have been extensively studied for BPV because of their high photosynthetic activity and ease of handling, their low EET activity poses a limitation. Here, we show an order-of-magnitude enhancement in photocurrent generation of the cyanobacterium Synechocystis sp. PCC 6803 by deprivation of the outer membrane, where electrons are suggested to stem from pathway(s) downstream of photosystem I. A marked enhancement of EET activity itself is verified by rapid reduction of exogenous electron acceptor, ferricyanide. The extracellular organic substances, including reducing equivalent(s), produced by this cyanobacterium serve as respiratory substrates for other heterotrophic bacteria. These findings demonstrate that the outer membrane is a barrier that limits EET. Therefore, depriving this membrane is an effective approach to exploit the cyanobacterial reducing equivalent(s).

Bipyridines mediate electron transfer from an electrode to nicotinamide adenine dinucleotide phosphate.

Biocatalysts are widely used in industry, but few examples of the use of oxidoreductases, in which enzymatic function often requires electrons, have been reported. NADPH is a cofactor that supplies an electron to oxidoreductases, but is consequently inactivated and no longer able to act as an electron donor. NADP+ can not receive electrons from electrodes through straightforward electrochemistry owing to its complicated three-dimensional structure. This study reports that bipyridines effectively mediate electron transfer between an electrode and NADP+, allowing them to serve as electron mediators for NADPH production. Using bipyridines, quinones, and anilines, which have negative oxidation-reduction potentials, an electrochemical investigation was conducted into whether electrons were transferred to NADP+. Only bipyridines with a reduction potential near -1.0 V exhibited electron transfer. Furthermore, the NADPH production level was measured using spectroscopy. NADPH was efficiently produced using bipyridines, such as methyl viologen and ethyl viologen, in which the bipyridyl 1- and 1'-positions bear small substituents. However, methyl viologen caused a dehydrogenation reaction of NADPH, making it unsuitable as an electron mediator for NADPH production. The dehydrogenation reaction did not occur using ethyl viologen. These results indicated that NADP+ can be reduced more effectively using substituents that prevent a dehydrogenation reaction at the bipyridyl 1- and 1'-positions while maintaining the reducing power.

Dehumidification at high temperature and high humidity by low-temperature regenerative polymers.

UCST-type poly(N-acryloylglycinamide-co-acrylonitrile), which aggregates at a low temperature in aqueous solutions and dissolves at a high temperature, adsorbed moisture at high temperature (50 °C) and high humidity (p/p0 = 0.96), and the adsorbent was regenerated at a low temperature (5 °C) even at high humidity (p/p0 = 0.96). The thermoresponsible behavior was caused by the decrease in the glass transition temperature by the adsorbed water.

Effects of trans-2-hexenal and cis-3-hexenal on post-harvest strawberry.

Green leaf volatiles are emitted by green plants and induce defence responses. Those with antifungal activities in plants may replace chemicals as natural post-harvest treatments. We investigated the postharvest treatment of strawberry with trans-2-hexenal and cis-3-hexenal and observed a decrease in the mould infection rate. To determine the volatiles' functions, we conducted a component analysis of the volatiles released from trans-2-hexenal-treated strawberry and analysed gene expression. Several acetates, which were expected to be metabolites of trans-2-hexenal in fruit, were released from treated strawberry; however, these acetates did not inhibit fungal growth. The gene expression analysis suggested that postharvest strawberries were not protected by jasmonic acid-mediated signalling but by another stress-related protein. Harvested strawberries experience stress induced by harvest-related injuries and are unable to perform photosynthesis, which might result in different responses than in normal plants.

Identifying stress markers in skin gases by analysing gas collected from subjects undergoing the Trier social stress test and performing statistical analysis.

In recent years, there has been great interest in mental health disorders. It is very important for people with mental health disorders to protect themselves from the stressful conditions that can occur as part of daily life before their symptoms become worse. We attempted to identify stress markers in skin gases in order to study the stress condition non-invasively in real time. We investigated changes in the skin gas components relative to the normal skin gas components of the subjects when stress was induced in the subjects using the Trier social stress test method, and we attempted to identify stress markers from those changes. We used a statistical analysis method and identified six stress markers in skin gases released from the armpits of the subjects.

300 mm Wafer-level, ultra-dense arrays of Au-capped nanopillars with sub-10 nm gaps as reliable SERS substrates.

The 193 nm deep UV immersion lithography is leveraged to fabricate highly dense and uniform arrays of Au-capped Si nanopillars on a 300 mm wafer level, and the substrates are applied in surface enhanced Raman spectroscopy for reliable molecule detection. Due to the sub-10 nm gap sizes and ultra-high array density with the lattice constant less than 100 nm, our nanopillar based substrates outperform the current commercial products in terms of the signal intensity, reproducibility and fabrication scale.

Giant cell tumor of the sternum: a case report and review of the literature.

Giant cell tumor (GCT) is a relatively common and locally aggressive benign bone tumor. The sternum is a rare location. To date, only four cases have been reported with detailed information. Here, we present a case with sternal GCT and discuss the clinical manifestation and treatment, in addition to reviewing the literature. A 53-year-old female noted pain in the sternum after a trauma. Radiographic findings revealed an expanding osteolytic lesion in the body of the sternum. Extended curettage of the tumor was performed followed by polymethylmethacrylate (PMMA) filing. No recurrence was found over a 7-year follow-up period. In conclusion, even though sternal benign tumors are rare, GCT should be considered as one of the differential diagnoses in a patient presenting with a sternal lesion in the 5th or 6th decade of life. The initial treatment should be extended curettage followed by filling with PMMA.

Picometer-scale dynamical observations of individual membrane proteins: the case of bacteriorhodopsin.

In vivo measurements of dynamical conformational changes in single biomolecules under functional conditions have had a tremendous impact on molecular and cell biology. However, even single-molecule fluorescent resonance energy transfer cannot easily monitor the intramolecular dynamics in cell systems due to shortcomings in monitoring precision. Here, we report dynamical observations of irreversible intramolecular conformational changes in a single-membrane protein [bacteriorhodopsin (BR)] using diffracted x-ray tracking. The light-driven proton pump BR is the best-characterized membrane protein. The position of BR's 35th amino acid, which is located farthest from retinal, exhibits a momentary positional jump of 0.73+/-0.48 A due to the expression of its function. Following that, we observed Brownian motion without the diffracted spots returning to their initial positions. The average width of this jump is about 14 times larger than that of thermal Brownian motion and agrees with estimated movements from known x-ray crystallography data. This result is an important step toward realizing in vivo observations of single-molecular conformational changes in membrane proteins.