Effects of Treadmill Exercise Combined with MK 801 Treatment on Neuroblast Differentiation in the Dentate Gyrus in Rats

N-methyl-d-aspartate receptor (NR) is involved in activity-dependent synaptic plasticity, such as associative long-term potentiation, and in related central functions, such as learning and memory. In this study, we observed effects of treadmill exercise on NR1 and doublecortin (DCX, a marker for neuroblast differentiation) in the subgranular zone of the dentate gyrus (DG). At 6 weeks of age, rats were put on a treadmill with or without running for 1 h/day for 5 consecutive days at 22 m/min for 5 weeks. Exercise increased NR1 immunoreactivity and protein level in the hippocampus. To identify the correlations between NR and neuroblasts, we intraperitoneally administered a NR antagonist, MK-801, to the exercised rats. MK-801 treatment reduced NR1 protein level in the hippocampus of the exercised rats. In addition, in the MK-801-treated group, the number of DCX cells was significantly decreased in the subgranular zone of the DG. These results suggest that NR may be one of the important factors that modulate neuroblast differentiation during exercise in rats.     

Genome sequence of the Shiga toxin-producing Escherichia coli strain NCCP15657

Shiga toxin-producing Escherichia coli causes bloody diarrhea and hemolytic-uremic syndrome and serious outbreaks worldwide. Here, we report the draft genome sequence of E. coli NCCP15657 isolated from a patient. The genome has virulence genes, many in the locus of enterocyte effacement (LEE) island, encoding a metalloprotease, the Shiga toxin, and constituents of type III secretion.     

LC–MS-based chemotaxonomic classification of wild-type Lespedeza sp. and its correlation with genotype

In this study, 39 specimens belonging to Lespedeza species (Lespedeza cyrtobotrya, L. bicolor, L. maximowiczii, and Lespedeza cuneata) (Leguminosae) were classified phenotypically and genotypically. We constructed a phylogenetic tree based on the combined nrDNA (internal transcribed spacer; ITS) and cpDNA (trnL-trnF) sequences with the aim of classifying the genotypes. Samples were mainly divided into three genotypes. Samples of L. cyrtobotrya and L. bicolor were mixed in a single branch, whereas samples of L. maximowiczii and L. cuneata were clustered within species, respectively. We performed a liquid chromatography–electrospray ionization–mass spectrometry-based metabolite profiling analysis to classify the phenotypes. Multivariate statistical analyses such as principal component analysis (PCA) and hierarchical clustering analysis (HCA) were used for the clustering pattern analysis and distance analysis between species, respectively. According to the PCA and HCA results, leaves were classified into four phenotypes according to species. In both the genetic and chemotaxonomic classification methods, the distance between L. cyrtobotrya and L. bicolor was the closest between species, and L. cuneata was the farthest away from the other three species. Additionally, orthogonal partial least squares-discriminant analysis was employed to identify significantly different phytochemicals between species. We classified L. cyrtobotrya and L. bicolor by identifying significantly different phytochemicals. Interestingly, leaves and stems showed different phenotypic classifications based on the chemotaxonomic classification. Stem samples of the other three species were mixed regardless of species, whereas L. cyrtobotrya stem samples were clustered within species. The phenotypic classification of leaves coincided more with the genotypic classification than that of stems. Key message We classified four wild-type Lespedeza sp. by analyzing the combined nrDNA (ITS) and cpDNA (trnL-trnF) sequences. We also classified leaves and stems of Lespedeza sp. by applying liquid chromatography–mass spectroscopy-based metabolite profiling.     

The expression of ketohexokinase is diminished in human clear cell type of renal cell carcinoma

For identification and targeting of tumor-associated marker proteins, the proteome of clear cell type of renal cell carcinoma (RCC) and normal kidney tissues was analyzed by 2-DE. Ketohexokinase (also called fructokinase), which catalyzes the phosphorylation of fructose to fructose 1-phosphate, was identified by MALDI-TOF MS and found to be expressed at low rates in the renal tumor tissues. We found a decreased amount of ketohexokinase mRNA in RCC compared to that observed in the normal kidney tissues by Northern blot. The activity of ketohexokinase in 20 clear cell RCC specimens and the 20 corresponding normal kidneys was investigated, and its activity was shown to be approximately 1.4-fold lower in the RCC specimens than in the normal kidney. Ketohexokinase activity in tumor stage pT3 RCC was 1.5-fold lower than in pT1 RCC. The level of ketohexokinase activity in histological grade 3 RCC was 1.8-fold lower than that in grade 1 cancer. In addition, using in situ hybridization, it was revealed that ketohexokinase in the normal kidney tissue was confined to the proximal tubular epithelial cells, while the expression of ketohexokinase in RCC tissues was extremely low. Our research results show that the expression of human ketohexokinase was diminished in clear cell RCC.     

Decreased Insulin-Like Growth Factor-I and Its Receptor Expression in the Hippocampus and Somatosensory Cortex of the Aged Mouse

Insulin-like growth factor-I (IGF-I) is a multifunctional polypeptide and has diverse effects on brain functions. In the present study, we compared IGF-I and IGF-I receptor (IGF-IR) immunoreactivity and their protein levels between the adult (postnatal month 6) and aged (postnatal month 24) mouse hippocampus and somatosensory cortex. In the adult hippocampus, IGF-I immunoreactivity was easily observed in the pyramidal cells of the stratum pyramidale in the hippocampus proper and in the granule cells of the granule cell layer of the dentate gyrus. In the adult somatosensory cortex, IGF-I immunoreactivity was easily found in the pyramidal cells of layer V. In the aged groups, IGF-I expression was dramatically decreased in the cells. Like the change of IGF-I immunoreactivity, IGF-IR immunoreactivity in the pyramidal and granule cells of the hippocampus and in the pyramidal cells of the somatosensory cortex was also markedly decreased in the aged group. In addition, both IGF-I and IGF-IR protein levels were significantly decreased in the aged hippocampus and somatosensory cortex. These results indicate that the apparent decrease of IGF-I and IGF-IR expression in the aged mouse hippocampus and somatosensory cortex may be related to age-related changes in the aged brain.     

Comparative analysis of nuclear proteins of B cells in different developmental stages

The developmental stage-specific regulation of V(D)J recombination, a gene rearrangement process of antigen receptor gene segments, is tightly controlled in cells. Here we screened proteins uniquely or differentially expressed among three developmentally distinguishable B cells (pro-B, pre-B and mature B cells) using two-dimensional gel electrophoresis and mass spectrometry. Chromatin assembly factor 1 was uniquely expressed in pro-B cells. Purine nucleotide phosphorylase, LCK, E2A and many other unidentified proteins were dominantly present in the nucleus at the early stage of B cell development where the V(D)J recombination process occurs. Also, few proteins including guanidine nucleotide binding proteins were exclusively expressed in pre-B cell. Such findings can provide some information to help understand the developmental regulation of gene rearrangement occurring during B cell development.     

Nodakenin, a coumarin compound, ameliorates scopolamine-induced memory disruption in mice

Nodakenin is a coumarin compound initially isolated from the roots of Angelica gigas. In the present study, we investigated the effects of nodakenin on learning and memory impairments induced by scopolamine (1 mg/kg, i.p.) using the passive avoidance test, the Y-maze test, and the Morris water maze test in mice. Nodakenin (10 mg/kg, p.o.) administration significantly reversed scopolamine-induced cognitive impairments in the passive avoidance test and the Y-maze test (P<0.05), and also reduced escape latency during training in the Morris water maze test (P<0.05). Moreover, swimming times and distances within the target zone of the Morris water maze were greater in the nodakenin-treated group than in the scopolamine-treated group (P<0.05). In an in vitro study, nodakenin was found to inhibit acetylcholinesterase activity in a dose-dependent manner (IC(50)=84.7 microM). In addition, nodakenin was also found to inhibit acetylcholinesterase activity for 6 h in an ex-vivo study. These results suggest that nodakenin may be a useful for the treatment of cognitive impairment, and that its beneficial effects are mediated, in part, via the enhancement of cholinergic signaling.     

Calcium Binding Proteins Immunoreactivity in the Rat Basolateral Amygdala Following Myocardial Infarction

In this study, we examined changes in immunoreactivities of calcium binding proteins, such as parvalbumin (PV), calbindin (CB), and calretinin (CR), in the rat basolateral amygdala (BLA) 14 days after myocardial infarction (MI). In the MI-operated group, numbers of PV and CB immunoreactive (⁺) neurons in the BLA were significantly reduced compared to those in the sham-operated group. However, numbers of CR⁺ neurons were slightly, not significantly, reduced in the MI-operated group. These results indicate that MI may decrease the immunoreactivities of PV and CB, not CR, in the rat BLA.     

Structural basis for binding of Plasmodium falciparum erythrocyte membrane protein 1 to chondroitin sulfate and placental tissue and the influence of protein polymorphisms on binding specificity

Chondroitin sulfate (CS) A is a key receptor for adhesion of Plasmodium falciparum-infected erythrocytes (IEs) in the placenta and can also mediate adhesion to microvascular endothelial cells. IEs that adhere to CSA express var2csa-type genes, which encode specific variants of the IE surface antigen P. falciparum erythrocyte membrane protein 1 (PfEMP1). We report direct binding of native PfEMP1, isolated from IEs and encoded by var2csa, to immobilized CSA. Binding of PfEMP1 was dependent on 4-O-sulfated disaccharides and glucuronic acid rather than iduronic acid, consistent with the specificity of intact IEs. Using immobilized CS oligosaccharides as neoglycolipid probes, the minimum chain length for direct binding of PfEMP1 was eight monosaccharide units. Similarly for IE adhesion to placental tissue there was a requirement for 4-O-sulfated GalNAc and glucuronic acid mixed with non-sulfated disaccharides; 6-O-sulfation interfered with the interaction between placental CSA and IEs. The minimum chain length for maximal inhibition of adhesion was 10 monosaccharide residues. Partially 4-O-sulfated CS oligosaccharides (45-55% sulfation) were highly effective inhibitors of placental adhesion (IC(50), 0.15 microg/ml) and may have potential for therapeutic development. We used defined P. falciparum isolates expressing different variants of var2csa in adhesion assays and found that there were isolate-specific differences in the preferred structural motifs for adhesion to CSA that correlated with polymorphisms in PfEMP1 encoded by var2csa-type genes. This may influence sites of IE sequestration or parasite virulence. These findings have significant implications for understanding the pathogenesis and biology of malaria, particularly during pregnancy, and the development of targeted interventions.