PI3K-Akt-mTORC1-S6K1/2 axis controls Th17 differentiation by regulating Gfi1 expression and nuclear translocation of RORγ

The PI3K-Akt-mTORC1 axis contributes to the activation, survival, and proliferation of CD4(+) T cells upon stimulation through TCR and CD28. Here, we demonstrate that the suppression of this axis by deletion of p85α or PI3K/mTORC1 inhibitors as well as T cell-specific deletion of raptor, an essential component of mTORC1, impairs Th17 differentiation in vitro and in vivo in a S6K1/2-dependent fashion. Inhibition of PI3K-Akt-mTORC1-S6K1 axis impairs the downregulation of Gfi1, a negative regulator of Th17 differentiation. Furthermore, we demonstrate that S6K2, a nuclear counterpart of S6K1, is induced by the PI3K-Akt-mTORC1 axis, binds RORγ, and carries RORγ to the nucleus. These results point toward a pivotal role of PI3K-Akt-mTORC1-S6K1/2 axis in Th17 differentiation.     

Evidence that protein kinase C (PKC) participates in the meiosis I to meiosis II transition in mouse oocytes.

Oocytes from LTXBO mice exhibit a delayed entry into anaphase I and frequently enter interphase after the first meiotic division. This unique oocyte model was used to test the hypothesis that protein kinase C (PKC) may regulate the meiosis I-to-meiosis II transition. PKC activity was detected in LTXBO oocytes at prophase I and increased with meiotic maturation, with the highest (P < 0.05) activity observed at late metaphase I (MI). Treatment of late MI-stage oocytes with the PKC inhibitor, bisindolylmaleimide I (BIM), transiently reduced (P < 0.05) M-phase-promoting factor (MPF) activity and promoted (P < 0.05) progression to metaphase II (MII), while mitogen-activated protein kinase (MAPK) activity remained elevated during the MI-to-MII transition. Confocal microscopy analysis of LTXBO oocytes during this transition showed PKC-delta associated with the meiotic spindle and then with the chromosomes at MII. Inhibition of PKC activity also prevented untimely entry into interphase, but only when PKC activity was reduced in oocytes before the progression to MII and thus indicates that the transition into interphase is directly associated with the delayed triggering of anaphase I. Moreover, the defect(s) that initiate activation occur upstream of MAPK, as suppression of PKC activity failed to prevent activation by Mos(tm1Ev)/ Mos(tm1Ev) LTXBO oocytes expressing no detectable MAPK activity. In summary, PKC participates in the regulatory mechanisms that delay entry into anaphase I in LTXBO oocytes, and the disruption promotes untimely entry into interphase. Thus, loss of regulatory control over PKC activity during oocyte maturation disrupts the critical MI-to-MII transition, leading to a precocious exit from meiosis.     

Importance of the understory stratum to entomofaunal diversity in a temperate deciduous forest

The vertical stratification of lepidopteran and coleopteran communities in a cool-temperate deciduous forest in Japan was examined to evaluate the hypothesis of an expected uniform distribution of mobile flying insects between the canopy and understory of temperate forests. Lepidopteran and coleopteran insects were trapped using light traps at three sites in each of the canopy and understory for three consecutive nights each month from April to October 2001. For Lepidoptera, species richness, abundance, and family richness were significantly higher in the understory than in the canopy. For Coleoptera, only abundance was larger in the canopy relative to the understory; species and family richness did not differ between the strata. The beta diversity of the lepidopteran community was larger between the strata than among sites, but the coleopteran community showed an inverse pattern. These results imply the presence of vertical stratification within the lepidopteran community, but not within the coleopteran community, in the temperate forest. The understory contributes more than the canopy to lepidopteran diversity in the temperate forest, although this stratification may be relatively weak because, in contrast to the situation in tropical forests, the canopy and understory assemblages share many species.     

Redox reactions via vanadium-induced electron transfer

One-electron reduction and oxidation induced by vanadium complexes are demonstrated to be useful in oxidative and reductive transformations of carbonyl compounds. The redox interaction between vanadium complexes and redox-active ligands is achieved with coenzyme PQQ and polyanilines that afford the corresponding redox systems.     

Carbonylation of cornified envelopes in the stratum corneum

Stratum corneum (SC), the outermost layer of the skin, is continuously exposed to oxidative stress via sunlight, lipid peroxidation, and is subsequently accompanied by oxidative modification. Previous studies have shown that major oxidative target proteins in the SC are keratins. However, it remains unclear to date whether cornified envelopes (CEs), protein envelopes of the corneocytes (cornified cells), would be oxidized. In this study, we first revealed oxidative modification of CEs using labeled hydrazide derivatives to detect carbonyl moieties. Carbonylation of CEs was confirmed by reaction with monoclonal antibodies against aldehyde-bound proteins, including anti-acrolein, anti-crotonaldehyde, anti-4-hydroxy-2-nonenal. The extent of carbonylation is stronger in CEs from the face, a sun-exposed area, than those from the inside of upper arm, an unexposed area. Carbonylation of CEs did not depend on their maturity, as evaluated by loss of involucrin antigenicity during maturation process, suggesting that CEs are carbonylated regardless of their maturation stage.     

Isolation and structure determination of algicidal compounds from Ulva fasciata

Thirty-seven species of seaweeds including 10 Chlorophyta, 13 Phaeophyta, and 14 Rhodophyta collected from the coast of Nagasaki Prefecture, Japan, were screened for algicidal activity against the red-tide phytoplankton Heterosigma akashiwo. The green alga Ulva fasciata (Ulvaceae, Chlorophyta) showed the strongest algicidal activity among the seaweeds tested. Bioassay-guided fractionation of the methanol extract of U. fasciata led to isolation of three algicidal compounds whose structures were determined to be hexadeca-4,7,10,13-tetraenoic acid (HDTA), octadeca-6,9,12,15-tetraenoic acid (ODTA), and alpha-linolenic acid on the basis of spectroscopic information. These polyunsaturated fatty acids (PUFAs) showed potent algicidal activity against H. akashiwo (LC(50) 1.35 microg/ml, 0.83 microg/ml, and 1.13 microg/ml for HDTA, ODTA, and alpha-linolenic acid, respectively), and the result demonstrated the potential of these PUFAs for practical harmful algal bloom control.     

Phylogeographical structure in Zelkova serrata in Japan and phylogeny in the genus Zelkova using the polymorphisms of chloroplast DNA

The genetic differentiation inherent in Zelkova serrata in Japan and the southern portion of the Korean Peninsula was examined by comparing a chloroplast DNA (cpDNA) sequence over a 16?k baselength in 40 individual samples collected from an area covering the natural distribution range of Z. serrata in Japan and the southern portion of the Korean Peninsula. We detected over 50 single-nucleotide polymorphisms in the protein-coding and intergenic regions, and over 30 insertions/deletions in the intergenic region. From the polymorphisms detected in the cpDNA, 14 haplotypes were identified. These 14 haplotypes had cluster-like structures and genetic differentiation between the clusters was large. Closely related haplotypes existed in adjacent regions. One haplotype existed in both Japan and the Korean Peninsula. By comparison with other Zelkova species, Z. serrata is apparently distinct from European and East Asian Zelkova species and Z. serrata is closest to the Ulmus species in the genus Zelkova. The effects of the analyzed length of the cpDNA sequence on the detection of polymorphisms were analyzed by re-sampling simulation.