CTENO64 Is Required for Coordinated Paddling of Ciliary Comb Plate in Ctenophores

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The Inner Nuclear Membrane Protein Bqt4 in Fission Yeast Contains a DNA-Binding Domain Essential for Telomere Association with the Nuclear Envelope

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Mutant analyses reveal different functions of fgfr1 in medaka and zebrafish despite conserved ligand-receptor relationships

Medaka (Oryzias latipes) is a small freshwater teleost that provides an excellent developmental genetic model complementary to zebrafish. Our recent mutagenesis screening using medaka identified headfish (hdf) which is characterized by the absence of trunk and tail structures with nearly normal head including the midbrain-hindbrain boundary (MHB). Positional-candidate cloning revealed that the hdf mutation causes a functionally null form of Fgfr1. The fgfr1hdf is thus the first fgf receptor mutant in fish. Although FGF signaling has been implicated in mesoderm induction, mesoderm is induced normally in the fgfr1hdf mutant, but subsequently, mutant embryos fail to maintain the mesoderm, leading to defects in mesoderm derivatives, especially in trunk and tail. Furthermore, we found that morpholino knockdown of medaka fgf8 resulted in a phenotype identical to the fgfr1hdf mutant, suggesting that like its mouse counterpart, Fgf8 is a major ligand for Fgfr1 in medaka early embryogenesis. Intriguingly, Fgf8 and Fgfr1 in zebrafish are also suggested to form a major ligand-receptor pair, but their function is much diverged, as the zebrafish fgfr1 morphant and zebrafish fgf8 mutant acerebellar (ace) only fail to develop the MHB, but develop nearly unaffected trunk and tail. These results provide evidence that teleost fish have evolved divergent functions of Fgf8-Fgfr1 while maintaining the ligand-receptor relationships. Comparative analysis using different fish is thus invaluable for shedding light on evolutionary diversification of gene function.     

Effect of N-terminal residues on the structural stability of recombinant horse L-chain apoferritin in an acidic environment

The denaturation of recombinant horse L-chain apoferritin (rLF), which is composed of 24 L-chain subunits, in acidic solution was studied. Using two rLF mutants, lacking four (Fer4) or eight (Fer8) N-terminal amino acid residues, the effect of N-terminal residues on the protein's stability was investigated. Of the two mutants and wild-type rLF, the tertiary and secondary structures of Fer8 were found to be most sensitive to an acidic environment. The Fer8 protein dissociated easily into subunit dimers at or below pH 2.0. Comparing the crystal structures of the mutant proteins, deletion of the N-terminal residues was found to result in fewer inter- and intra-subunit hydrogen bonds. The loss of these bonds is assumed to be responsible for lower endurance against acidic denaturation in N-terminus-deleted mutants. These results indicated that the inter- and intra-subunit hydrogen bonds of N-terminal residues affect the denaturation, especially oligomer formation of apoferritin subunits and will be of use in designing ferritin-based nanodevices.     

Involvement of basal metabolic rate in determination of type of cold tolerance

This study aimed to assess the relationship between basal metabolic rate (BMR) and metabolic heat production, and to clarify the involvement of BMR in determining the phenotype of cold tolerance. Measurements of BMR, maximum oxygen uptake, and cold exposure test were conducted on ten males. In the cold exposure test, rectal (T(rec)) and mean skin temperatures (T(ms)), oxygen uptake, and blood flow at forearm (BF(arm)) were measured during exposure to cold (10 degrees C) for 90 min. Significant correlations were observed between BMR and increasing rate of oxygen uptake, as well as between decreasing rate of BF(arm) and increasing rate of oxygen uptake at the end of cold exposure. These findings suggested that individuals with a lower BMR were required to increase their metabolic heat production during cold exposure, and that those with a higher BMR were able to moderate increased metabolic heat production during cold exposure because they were able to reduce heat loss. This study showed that BMR is an important factor in determining the phenotype of cold tolerance, and that individuals with a low BMR showed calorigenic-type cold adaptation, whereas subjects with a high BMR exhibited adiabatic-type cold adaptation by peripheral vasoconstriction.     

Fern gametophytes of Angiopteris lygodiifolia and Osmunda japonica harbor diverse Mucoromycotina fungi

Journal of Plant Research - Mycorrhizal symbiosis between plants and fungi is ubiquitous, and has been played key roles in plant terrestrialization and diversification. Although arbuscular...     

Determination of human plasma xanthine oxidase activity by high-performance liquid chromatography

An assay for human plasma xanthine oxidase activity was developed with pterin as the substrate and the separation of product (isoxanthopterin) by high-performance liquid chromatography with a fluorescence detector. The reaction mixture consists of 60 μl of plasma and 240 μl of 0.2 M Tris-HCl buffer (pH 9.0) containing 113 μM pterin. With this assay, the activity of plasma xanthine oxidase could be easily determined despite its low activity. As a result, it could be demonstrated that the intravenous administration of heparin or the oral administration of ethanol did not increase plasma xanthine oxidase activity in normal subjects, and also that plasma xanthine oxidase activity was higher in patients with hepatitis C virus infection than in healthy subjects or patients with gout. In addition, a single patient with von Gierke's disease showed a marked increase in the plasma activity of this enzyme, relative to that apparent in normal subjects.     

FTIR spectroscopic analyses of human placental membranes

We investigated the differences in the Fourier transform infrared (FTIR) spectra of normal and abnormal human placentas. Normal placentas, placentas with infant intrauterine growth restriction (IUGR), and placentas from mothers with diabetes mellitus (DM) were used, none of which had been treated before measurement. The tissues were divided into three parts: the upper one-third portion (P1), the middle portion (P2), and the lower one-third portion (P3). Placental tissues were also investigated histochemically. The differences of the main second-derivative FTIR spectra among P1, P2, and P3 in normal placentas were observed in bands appearing between 1080 and 1090 cm(-1). Bands in P2 were observed at 1083 cm(-1), which was significantly higher than that in P3 (p < 0.05). The spectrum of P2 tissue in placentas with infant IUGR had a peak at 1081 cm(-1), which was significantly different from those of P1 and P3 (p < 0.05). In placentas with DM, the P2 band was shifted to a peak at 1088 cm(-1). These data were well correlated with the histochemical sugar-chain staining pattern of the P2 portion of the placenta. Our data suggested that this IR technique is applicable to the clinical diagnosis of diseases in the gynecological field.     

Involvement of serum mannan binding proteins and mannose receptors in uptake of mannosylated liposomes by macrophages

The roles of serum mannan binding protein (MBP) and the mannose receptor in the cellular uptake of mannosylated liposomes (Man-liposomes) by macrophages were studied. Man-liposomes were prepared by incorporating cholesten-5-yloxy-N-(4-((1-imino-2-beta-D-thiomannosylethyl)amino)butyl)formamide (Man-C4-Chol) into small unilamellar long circulating liposomes consisting of cholesterol (Chol) and distearoyl phosphatidylcholine (DSPC). In the in vitro cellular uptake study with cultured mouse peritoneal macrophages, [(3)H]Man-liposomes were taken up to a great extent, whereas no significant uptake was observed for [(3)H]cholesterol and DSPC liposomes without Man-C4-Chol (Bare-liposomes). The uptake of [(3)H]Man-liposomes was dose- and temperature-dependent and inhibited by an excess of mannosylated bovine serum albumin, suggesting their specific uptake via membrane mannose receptor-mediated endocytosis. Furthermore, it was demonstrated that (111)In-MBP binds strongly to Man-liposomes based on the recognition of Man-C4-Chol and markedly enhanced their uptake by macrophages. These results are supported by confocal laser microscopic images. In addition, in vivo hepatic uptake of (111)In-MBP was enhanced by Man-liposomes. On the other hand, the uptake of Man-liposomes was significantly reduced by preincubation with serum and further with MBP-depleted serum suggesting inhibitory effects of serum proteins such as albumin on mannose receptor-mediated endocytosis. The involvement of serum-type MBP and membrane mannose receptors in the uptake of Man-liposomes is thus suggested.