Analysis of chorion hardening of eggs of rainbow trout, Oncorhynchus mykiss

We estimated changes of chorion hardness of rainbow trout (Oncorhynchus mykiss) egg by the use of three parameters, namely increase of resistance of an egg to rupture by extraneously applied pressure, decrease of solubility of chorion proteins in 8 mol/L urea and a change in the content of γ-glutamyl-ε-lysine crosslink. Unfertilized egg chorions became hardened after egg activation. During chorion hardening, 49, 56 and 65 kDa protein components of the chorion gradually disappeared, high molecular weight intermediates (113,160–170 and higher than 250 kDa) were newly formed and, finally, all components became undetectable by sodium dodecylsulfate-polyacrylamide gel electrophoresis. The content of γ-glutamyl-ε-lysine (γ-Glu-ε-Lys) crosslink in the chorion increased after hardening. Chorion hardening was inhibited by the incorporation of monodansyl-cadaverine, a competitive inhibitor for transglutaminase (TGase), into the chorions. TGase activity was detected in unfertilized eggs and localized in the chorion fraction rather than in the ooplasmic fraction. The findings suggest that chorion hardening depends upon polymerization of the chorion components by TGase-dependent γ-Glu-ε-Lys crosslink formation.     

Three-Dimensional Labeling Program for Elucidation of the Geometric Properties of Biological Particles in Three-Dimensional Space

For all biological particles such as cells or cellular organelles, there are three-dimensional coordinates representing the centroid or center of gravity. These coordinates and other numerical parameters such as volume, fluorescence intensity, surface area, and shape are referred to in this paper as geometric properties, which may provide critical information for the clarification ofin situmechanisms of molecular and cellular functions in living organisms. We have established a method for the elucidation of these properties, designated the three-dimensional labeling program (3DLP). Algorithms of 3DLP are so simple that this method can be carried out through the use of software combinations in image analysis on a personal computer. To evaluate 3DLP, it was applied to a 32-cell-stage sea urchin embryo, double stained with FITC for cellular protein of blastomeres and propidium iodide for nuclear DNA. A stack of optical serial section images was obtained by confocal laser scanning microscopy. The method was found effective for determining geometric properties and should prove applicable to the study of many different kinds of biological particles in three-dimensional space.     

Phospholipase D production using immobilized cells of Streptoverticillium cinnamoneum

Summary Production of phospholipase D (PLD) by Streptoverticillium cinnamoneum immobilized within porous particles was investigated in repeated batch fermentation. The enzyme productivity in repeated batch fermentation was 2.2-fold that obtained in batch fermentation without immobilization, since many of the immobilized cells could be utilized as seed cells for each subsequent batch cycle.     

Distribution of Glycinebetaine in Old and Young Leaf Blades of Salt-Stressed Barley Plants

In barley plants exposed to stepwise salt-stress (up to 200mM NaCl), sodium and chloride ions accumulated preferentiallyin old rather than in young leaf blades. Furthermore, the levelof glycinebetaine in young leaf blades was approximately threetimes that in old leaf blades. ³Present address: Department of Biochemistry, Faculty of Science,Kasesart University, Bangkok, 10900 Thailand     

Prediction of the Coding Sequences of Unidentified Human Genes. IV. The Coding Sequences of 40 New Genes (KIAA0121-KIAA0160) Deduced by Analysis of cDNA Clones from Human Cell Line KG-1

In this series of projects regarding the accumulation of sequenceinformation of unidentified human genes, we newly deduced thesequences of 40 full-length cDNA clones of human cell line KG-1,and predicted the coding sequences of the corresponding genes,named KIAA0121 to 0160. The results of a computer search ofpublic databases indicated that the sequences of 13 genes wereunrelated to any reported genes, while the remaining 27 genescarried sequences which showed some similarities to known genes.Obvious unique sequences noted were as follows. A stretch oftriplet repeats was contained in each of three genes: Thesewere GAG(Glu) in KIAA0122 and KIAA0147, and TCC(Ser) in KIAA0150.A stretch of 10 amino acidresidues was repeated 21 times inKIAA0139, and a homologous sequence of 76–78 nucleotideswas found repeated 6 times in the untranslated region of KIAA0125.northern hybridization analysis demonstrated that 13 genes wereexpressed in a cell- or tissue-specific manner. Although a vastnumber of expressed sequence tags (ESTs) have been registeredfor comprehensive analysis of cDNA clones, our sequence dataindicated that their distribution is very unbalanced: e.g. whileno EST hit 7 genes, 85 ESTs fell in a single gene.     

Nucleotide Sequence Surrounding the Locus Marker D21S246 on Human Chromosome 21

Most ofthe human Not I linking clones identified to date areconsidered to be derived from CpG islands because ofthe recognitionsequence of this enzyme, and CpG islands have been reportedto be located around the 5' regions of genes. As a pilot study,we determined the complete nucleotide sequence (41,924 bp) ofa human cosmid clone (LL21NC02Q7A10) containing the marker D21S246originating from a Not I linking clone. As a result of sequenceanalysis, we successfully mapped and revealed the genomic genestructure for KIAA0002 previously reported as a cDNA clone.This gene consists of 15 exons and was shown to exist at theD21S246 locus on human chromosome 21q21.3–q22.1. Theseresults demonstrated that genomic marker-anchored DNA sequencingis a useful approach for the human genome project.     

Global bifurcation structure of a Bonhoeffer-van der Pol oscillator driven by periodic pulse trains

The Bonhoeffer-van der Pol (BVP) oscillator is a valuable dynamical system model of pacemaker neurons. Isochrons, phase transition curves (PTC), and two dimensional bifurcation diagrams served to analyze the neuron's response to periodic pulse stimuli. Responses are described and explained in terms of the nonlinear dynamical system theory. An important issue in the generation of spikes by pacemaker neurons is the existence of both slow and fast dynamics in the state point's trajectory in the phase plane. It is this feature in particular that makes the BVP oscillator a faithful model of living pacemaker neurons. Comparison of the model's responses with those of a living pacemaker was based also on return maps of interspike intervals. Analyzed in detail were the complex discharges called stammering which involve interspike intervals that arise unpredictably and exhibit histograms with several modes separated by the equal intervals.Supported by Trent H. Wells Jr. Inc.     

A model for neural representation of binocular disparity in striate cortex: distributed representation and veto mechanism

A model in striate cortex is proposed for a distributed neural representation of binocular disparity with a simple cell. In the model, disparity is represented by far, near and tuned inhibitory simple cells. However, the representation will be vetoed by model cells where disparity is excessively large. The veto mechanism consists of a neural network of the model cell which received output from simple cells and which interacts with neighbors. The mechanism is necessary, the model cell responds like a simple cell, and the network is physiologically plausible in the brain. Computer simulation on the neural network model with random dot stereography indicates reasonable performance.