Integumental reddish-violet coloration owing to novel dichromatic chromatophores in the teleost fish, Pseudochromis diadema

In the reddish-violet parts of the skin of the diadema pseudochromis Pseudochromis diadema, we found novel dichromatic chromatophores with a reddish pigment and reflecting platelets. We named these novel cells 'erythro-iridophores'. In standard physiological solution, erythro-iridophores displayed two hues, red and dark violet when viewed with an optical microscope under ordinary transmission light and epi-illumination optics, respectively. Under transmission electron microscopy, however, we observed no typical red chromatosomes, i.e., erythrosomes, in the cytoplasm. High-performance thin-layer chromatography (HPTLC) analysis of the pigment eluted from the erythro-iridophores indicated that carotenoid is the main pigment generating the reddish color. Furthermore, when the irrigating medium was a K(+)-rich saline solution, the color reflected from the erythro-iridophores changed from dark violet to sky blue, but the red coloration remained. The motile activities of the erythro-iridophores may participate in the changes in the reddish-violet shades of the pseudochromis fish.     

Structural difference of vasoactive intestinal peptide in two distinct membrane-mimicking environments

Vasoactive intestinal peptide (VIP) is a 28-amino acid neuropeptide which belongs to a glucagon/secretin superfamily, the ligand of class II G protein-coupled receptors. Knowledge for the conformation of VIP bound to membrane is important because the receptor activation is initiated by membrane binding of VIP. We have previously observed that VIP-G (glycine-extended VIP) is unstructured in solution, as evidenced by the limited NMR chemical shift dispersion. In this study, we determined the three-dimensional structures of VIP-G in two distinct membrane-mimicking environments. Although these are basically similar structures composed of a disordered N-terminal region and a long α-helix, micelle-bound VIP-G has a curved α-helix. The side chains of residues Phe(6), Tyr(10), Leu(13), and Met(17) found at the concave face form a hydrophobic patch in the micelle-bound state. The structural differences in two distinct membrane-mimicking environments show that the micelle-bound VIP-G localized at the water-micelle boundary with these side chains toward micelle interior. In micelle-bound PACAP-38 (one of the glucagon/secretin superfamily peptide) structure, the identical hydrophobic residues form the micelle-binding interface. This result suggests that these residues play an important role for the membrane binding of VIP and PACAP.     

Long-term variation in abundance of the non-native phytoplankton Micrasterias hardyi (Zygnematophyceae,Streptophyta) in Lake Biwa,Japan

Limnology - Alien species have invaded worldwide and altered native biodiversity and ecosystem functions. In Lake Biwa, Japan, Micrasterias hardyi—considered an endemic species in...     

Regulation of Glycolysis by Pdk Functions as a Metabolic Checkpoint for Cell Cycle Quiescence in Hematopoietic Stem Cells

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Highlights? LT-HSCs activate glycolysis and generate ATP in a HIF-1α-dependent manner ? Pdk overexpression in HIF-1α^Δ/Δ HSCs restored glycolysis and stem cell capacity ? Pdk2^?/?: Pdk4^?/? LT-HSCs show defective glycolysis and cell cycle quiescence ? Pdk mimetic promotes the survival and transplantation capacity of LT-HSCs     

Cell plate restricted association of DRP1A and PIN proteins is required for cell polarity establishment in Arabidopsis

The polarized transport of the phytohormone auxin [1], which is crucial for the regulation of different stages of plant development [2, 3], depends on the asymmetric plasma membrane distribution of the PIN-FORMED (PIN) auxin efflux carriers [4,?5]. The PIN polar localization results from clathrin-mediated endocytosis (CME) from the plasma membrane and subsequent polar recycling [6]. The Arabidopsis genome encodes two groups of dynamin-related proteins (DRPs) that show homology to mammalian dynamin-a protein required for fission of endocytic vesicles during CME [7, 8]. Here we show by coimmunoprecipitation (coIP), bimolecular fluorescence complementation (BiFC), and F?rster resonance energy transfer (FRET) that members of the DRP1 group closely associate with PIN proteins at the cell plate. Localization and phenotypic analysis of novel drp1 mutants revealed a requirement for DRP1 function in correct PIN distribution and in auxin-mediated development. We propose that rapid and specific internalization of PIN proteins mediated by the DRP1 proteins and the associated CME machinery from the cell plate membranes during cytokinesis is an important mechanism for proper polar PIN positioning in interphase cells.     

Exploration of larger central ring linkers in furamidine analogues: synthesis and evaluation of their DNA binding, antiparasitic and fluorescence properties

The effects of replacing the central furan ring of furamidine with indole and benzimidazole on their DNA binding affinity, antiparasitic activity and fluorescence are reported. The bis-cyanophenylindoles required to make the corresponding amidines were prepared by sequential Stille and/or Suzuki coupling reactions. The bis-cyanophenylbenzimidazoles were obtained by coupling 4-cyanobenzaldehydes with the appropriate cyano substituted phenylenediamine. The bis-nitriles were converted to the diamidines by reaction with LiN[Si(CH(3))(3)](2) or by Pinner methodology. Specifically, we have prepared new series of 2,6- and 2,5-diaryl indoles (6a,b, 12 and 17a-d) and the related benzimidazoles (24, 30 and 35). The new compounds bind in the DNA minor groove in DNA AT base pair sequences and eight of the ten new analogues exhibit ΔT(m) values comparable to or higher than that of furamidine. Six of ten of the new compounds exhibit lower IC(50) values against Trypanosoma brucei rhodesiense (T. b. r.) and eight of ten exhibit lower IC(50) values against Plasmodium falciparum (P. f.) than furamidine. Four of the ten show greater efficacy than furamidine in the rigorous T. b. r. STIB900 mouse model for African trypanosomiasis. Generally, the fluorescence properties of the new analogues are similar to that of DAPI.