Pathological changes of myocardial cytoskeleton in cardiomyopathic hamster

Immunocytochemical investigation was performed on the cytoskeletal proteins in cardiac tissue of the cardiomyopathic hamster. Male cardiomyopathic UM-X7.1 hamsters at 180 days of age (n=8) and age- and sex-matched normal BIO-RB hamsters (n=8) were used in this study. Immunofluorescence microscopy using monoclonal antibodies against desmin, -actinin, titin, and vincullin was employed. The heart weight to body weight ratio was significantly increased in the heart of cardiomyopathic hamster compared with that of normal hamster. In cardiomyopathic hamster, the left ventricular cavity was markedly dilated. Light microscopically, hypertrophy and atrophy of myocytes and myocardial fibrosis were prominently observed in cardiomyopathic myocardium. Immunocytochemically, desmin, -actinin and titin showed the cross striations along the myofibers in normal myocardium. In contrast, in cardiomyopathic myocardium, desmin was irregularly distributed in myocytes and the amount of desmin was increased. Loss of cross striations of -actinin and titin were frequently observed. Immunofluorescence against vinculin was not significantly altered. We conclude that the alterations of cytoskeletal proteins in myocardial cells may relate to decreased myocardial function in cardiomyopathic hamster failing heart.     

Experimental Approach Reveals the Role of alx1 in the Evolution of the Echinoderm Larval Skeleton

Over the course of evolution, the acquisition of novel structures has ultimately led to wide variation in morphology among extant multicellular organisms. Thus, the origins of genetic systems for new morphological structures are a subject of great interest in evolutionary biology. The larval skeleton is a novel structure acquired in some echinoderm lineages via the activation of the adult skeletogenic machinery. Previously, VEGF signaling was suggested to have played an important role in the acquisition of the larval skeleton. In the present study, we compared expression patterns of Alx genes among echinoderm classes to further explore the factors involved in the acquisition of a larval skeleton. We found that the alx1 gene, originally described as crucial for sea urchin skeletogenesis, may have also played an essential role in the evolution of the larval skeleton. Unlike those echinoderms that have a larval skeleton, we found that alx1 of starfish was barely expressed in early larvae that have no skeleton. When alx1 overexpression was induced via injection of alx1 mRNA into starfish eggs, the expression patterns of certain genes, including those possibly involved in skeletogenesis, were altered. This suggested that a portion of the skeletogenic program was induced solely by alx1. However, we observed no obvious external phenotype or skeleton. We concluded that alx1 was necessary but not sufficient for the acquisition of the larval skeleton, which, in fact, requires several genetic events. Based on these results, we discuss how the larval expression of alx1 contributed to the acquisition of the larval skeleton in the putative ancestral lineage of echinoderms.     

Exercise-induced enhancement of insulin sensitivity is associated with accumulation of M2-polarized macrophages in mouse skeletal muscle

Exercise enhances insulin sensitivity in skeletal muscle, but the underlying mechanism remains obscure. Recent data suggest that alternatively activated M2 macrophages enhance insulin sensitivity in insulin target organs such as adipose tissue and liver. Therefore, the aim of this study was to determine the role of anti-inflammatory M2 macrophages in exercise-induced enhancement of insulin sensitivity in skeletal muscle. C57BL6J mice underwent a single bout of treadmill running (20 m/min, 90 min). Twenty-four hours later, ex vivo insulin-stimulated 2-deoxy glucose uptake was found to be increased in plantaris muscle. This change was associated with increased number of CD163-expressing macrophages (i.e. M2-polarized macrophages) in skeletal muscle. Systemic depletion of macrophages by pretreatment of mice with clodronate-containing liposome abrogated both CD163-positive macrophage accumulation in skeletal muscle as well as the enhancement of insulin sensitivity after exercise, without affecting insulin-induced phosphorylation of Akt and AS160 or exercise-induced GLUT4 expression. These results suggest that accumulation of M2-polarized macrophages is involved in exercise-induced enhancement of insulin sensitivity in mouse skeletal muscle, independently of the phosphorylation of Akt and AS160 and expression of GLUT4.     

Turbidimetric Evaluation of Yeast Cell Amount

It was found that the intercellular space of centrifuged sake yeast cultured in anaerobic medium is 0.263 ml/g, which is larger than that of bakers’ yeast. On the preparation of the calibration curve, this centrifuged sake yeast wras used as standard substance.

The diameters of the majority of cells were included in a range of 3~8_µ during the whole course of cultural development. A similar distribution was found on the cells cultured in an abnormal medium. From these results, clearly, the turbidimetric method for the evaluation of the cell amount of yeast cultured anaerobically is unaffected by the cultural conditions.     

Biochemical Studies on the Mineral Components in Sake Yeast

The critical concentrations of minerals in a growing medium for maximum fermentation of yeast were as follows: P, 1 mmol/1; Mg, 0.2 mmol/1; and K, 1~2 mmol/1. These values are lower than those for the saturation of the cells with each mineral. The order of the concentration for maximum fermentation (K>P>Mg) is in agreement with that for yeast growth.

Only a small amount of mineral salt was required to increase the fermentative activity. Very small increase of fermentative activity was observed when the starved yeast was enriched with corresponding minerals by incubating cells with the mineral salt and glucose.     

The daidzein- and estradiol- induced anorectic action in CCK or leptin receptor deficiency rats

We investigated the effect of daidzein feeding and estradiol treatment on food intake in cholecystokinin-1 receptor (CCK1R) deficiency, leptin receptor (ObRb) deficiency rats and their wild-type rats. These rats underwent an ovariectomy or a sham operation. For the 5 week experiment, each rat was divided in three groups: control, daidzein (150 mg/kg diet), and estradiol (4.2 μg/rat/day) groups. In both CCK1R+ and CCK1R? rats, daidzein feeding and estradiol treatment significantly decreased food intake. Daidzein feeding significantly reduced food intake in ovariectomized ObRb? rats, although not in ObRb+ rats. Estradiol treatment significantly lowered food intake in ovariectomized ObRb+ and ObRb? rats. In the ovariectomized rats, estradiol treatment significantly increases uterine weight, while daidzein feeding did not change it, suggesting that daidzein might have no or weak estrogenic effect in our experiment. These results suggest that CCK1R and ObRb signalings were not essential for the daidzein- and estradiol-induced anorectic action.     

Affinity Improvement of a Cancer-Targeted Antibody through Alanine-Induced Adjustment of Antigen-Antibody Interface

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Structural transition of a 15 amino acid residue peptide induced by GM1

The ganglioside GM1-binding peptide, p3, with a sequence of VWRLLAPPFSNRLLP, displayed a clear structural alteration depending on the presence or absence of GM1 micelles. The three-dimensional structures of the p3 peptide in the free and GM1 bound states were analyzed using two-dimensional NMR spectroscopic experiments with distance-restrained simulated annealing calculations. The NMR experiments for the p3 peptide alone indicated that the peptide has two conformers derived from the exchange of cis and trans forms at Pro(7)-Pro(8). Further study with theoretical modeling revealed that the p3 peptide has a curb conformation without regular secondary structure. On the other hand, the NMR studies for the p3 peptide with the GM1 micelles elucidated a trans conformer and gave a structure stabilized by hydrophobic interactions of beta- and helical turns. Based on these structural investigations, tryptophan, a core residue of the hydrophobic cluster, might be an essential residue for the recognition of the GM1 saccharides. The dynamic transition of the p3 peptide may play an important role in the function of GM1 as a multiple receptor as in the traditional pathway of the infection by cholera toxin.