Light-driven proton-pumping rhodopsins are widely distributed in many microorganisms. They convert sunlight energy into proton gradients that serve as energy source of the cell. Here we report a new functional class of a microbial rhodopsin, a light-driven sodium ion pump. We discover that the marine flavobacterium Krokinobacter eikastus possesses two rhodopsins, the first, KR1, being a prototypical proton pump, while the second, KR2, pumps sodium ions outward. Rhodopsin KR2 can also pump lithium ions, but converts to a proton pump when presented with potassium chloride or salts of larger cations. These data indicate that KR2 is a compatible sodium ion-proton pump, and spectroscopic analysis showed it binds sodium ions in its extracellular domain. These findings suggest that light-driven sodium pumps may be as important in situ as their proton-pumping counterparts.

By using 1,4-dioxane as the sole source of carbon, a 1,4-dioxane-degrading microorganism was isolated from soil. The fungus, termed strain A, was able to utilize 1,4-dioxane and many kinds of cyclic ethers as the sole source of carbon and was identified as Cordyceps sinensis from its 18S rRNA gene sequence. Ethylene glycol was identified as a degradation product of 1,4-dioxane by the use of deuterated 1,4-dioxane-d 8 and gas chromatography-mass spectrometry analysis. A degradation pathway involving ethylene glycol, glycolic acid, and oxalic acid was proposed, followed by incorporation of the glycolic acid and/or oxalic acid via glyoxylic acid into the tricarboxylic acid cycle.

Silver nanoclusters have attracted scientific interest due to their properties and applications. However, practical synthetic methods to access these materials are still limited mainly due to the low stability. Here, we report a controlled assembly strategy for fabricating atomically precise silver nanoclusters using polyoxometalates (POMs) as structure-directing as well as functionalizing units. A trefoil-propeller-shaped {Ag27}17+ nanocluster was synthesized by assembling reactive nanoclusters supported by open-Dawson-type POMs [Si2W18O66]16–. The {Ag27}17+ nanocluster possessed 10 delocalized valence electrons and showed unprecedented ultrastability in solutions. The cluster showed unique {Ag27}-to-POM charge transfer bands in the visible light region.

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Indoleamine 2,3-dioxygenase, the l-tryptophan–degrading enzyme, plays a key role in the powerful immunomodulatory effects on several different types of cells. Because modulation of IDO activities after viral infection may have great impact on disease progression, we investigated the role of IDO following infection with LP-BM5 murine leukemia virus. We found suppressed BM5 provirus copies and increased type I IFNs in the spleen from IDO knockout (IDO−/−) and 1-methyl-d-l-tryptophan–treated mice compared with those from wild-type (WT) mice. Additionally, the number of plasmacytoid dendritic cells in IDO−/− mice was higher in the former than in the WT mice. In addition, neutralization of type I IFNs in IDO−/− mice resulted in an increase in LP-BM5 viral replication. Moreover, the survival rate of IDO−/− mice or 1-methyl-d-l-tryptophan–treated mice infected with LP-BM5 alone or with both Toxoplasma gondii and LP-BM5 was clearly greater than the survival rate of WT mice. To our knowledge, the present study is the first report to observe suppressed virus replication with upregulated type I IFN in IDO−/− mice, suggesting that modulation of the IDO pathway may be an effective strategy for treatment of virus infection.

BackgroundThe Japan Environment and Children’s Study (JECS) is an ongoing nationwide birth cohort study launched in January 2011. In this progress report, we present data collected in the first year to summarize selected maternal and infant characteristics.MethodsIn the 15 Regional Centers located throughout Japan, the expectant mothers were recruited in early pregnancy at obstetric facilities and/or at local government offices issuing pregnancy journals. Self-administered questionnaires were distributed to the women during their first trimester and then again during the second or third trimester to obtain information on demographic factors, physical and mental health, lifestyle, occupation, environmental exposure, dwelling conditions, and socioeconomic status. Information was obtained from medical records in the first trimester and after delivery on medical history, including gravidity and related complications, parity, maternal anthropometry, and infant physical examinations.ResultsWe collected data on a total of 9819 expectant mothers (mean age = 31.0 years) who gave birth during 2011. There were 9635 live births. The selected infant characteristics (singleton births, gestational age at birth, sex, birth weight) in the JECS population were similar to those in national survey data on the Japanese general population.ConclusionsOur final birth data will eventually be used to evaluate the national representativeness of the JECS population. We hope the JECS will provide valuable information on the impact of the environment in which our children live on their health and development.

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Proteorhodopsin (PR) genes are widely distributed among marine prokaryotes and functions as light-driven proton pump when expressed heterologously in Escherichia coli, suggesting that light energy passing through PR may be substantial in marine environment. However, there are no data on PR proton pump activities in native marine bacteria. Here, we demonstrate light-driven proton pump activity (c. 124 H(+) PR(-1)  min(-1) ) in recently isolated marine Flavobacteria. Among 75 isolates, 38 possessed the PR gene. Illumination of cell suspensions from all eight tested strains in five genera triggered marked pH drops. The action spectrum of proton pump activity closely matched the spectral distribution of the sea surface green light field. Addition of hydroxylamine to a solubilized membrane fraction shifted the spectrum to a form characteristic of PR photobleached into retinal oxime, indicating that PRs in flavobacterial cell membranes transform the photon dose in incident radiation into energy in the form of membrane potential. Our results revealed that PR-mediated proton transport can create the sufficient membrane potential for the ATP synthesis in native flavobacterial cells.