Effects of G-CSF on cardiac remodeling after acute myocardial infarction in swine

We examined whether granulocyte colony-stimulating factor (G-CSF) prevents cardiac dysfunction and remodeling after myocardial infarction (MI) in large animals. MI was produced by ligation of left anterior descending coronary artery in swine. G-CSF (10 microg/kg/day, once a day) was injected subcutaneously from 24h after ligation for 7 days. Echocardiographic examination revealed that the G-CSF treatment induced improvement of cardiac function and attenuation of cardiac remodeling at 4 weeks after MI. In the ischemic region, the number of apoptotic endothelial cells was smaller and the number of vessels was larger in the G-CSF treatment group than in control group. Moreover, vascular endothelial growth factor was more abundantly expressed and Akt was more strongly activated in the ischemic region of the G-CSF treatment group than of control group. These findings suggest that G-CSF prevents cardiac dysfunction and remodeling after MI in large animals.     

Biological evaluation of sphingomyelin analogues as inhibitors of sphingomyelinase

Seeking neutral sphingomyelinase inhibitors, we designed and synthesized hydrolytically stable analogues of sphingomyelin. These novel analogues replace the phosphodiester moiety of sphingomyelin with carbamate and urea moiety, resulting in inhibition of neutral sphingomyelinase. Compound 1 prevented ceramide generation and apoptotic neuronal cell death in a model of ischemia based on organotypic hippocampal slice cultures.     

Development of a PCR-based mating-type assay for Clavicipitaceae

A new controlled production system to target heterologous proteins to cytoplasm or extracellular medium is described for Lactococcus lactis NCDO2118. It is based on the use of a xylose-inducible lactococcal promoter, P(xylT). The capacities of this system to produce cytoplasmic and secreted proteins were tested using the Staphylococcus aureus nuclease gene (nuc) fused or not to the lactococcal Usp45 signal peptide. Xylose-inducible nuc expression is tightly controlled and resulted in high-level and long-term protein production, and correct targeting either to the cytoplasm or to the extracellular medium. Furthermore, this expression system is versatile and can be switched on or off easily by adding either xylose or glucose, respectively. These results confirm the potential of this expression system as an alternative and useful tool for the production of proteins of interest in L. lactis.     

Nucleolin and the packaging signal, psi, promote the budding of human immunodeficiency virus type-1 (HIV-1)

Gag proteins of human immunodeficiency virus type 1 (HIV-1) play a pivotal role in the budding of the virion, in which the zinc finger motifs of the gag proteins recognize the packaging signal of genomic RNA. Nucleolin, an RNA-binding protein, is identified as a cellular protein that binds to murine leukemia virus (MuLV) gag proteins and regulates the viral budding, suggesting that HIV-1 gag proteins, the packaging signal, psi and nucleolin affect the budding of HIV-1. Here we report that nucleolin enhances the release of HIV-1 virions which contain psi. Furthermore, nucleolin and gag proteins form a complex incorporated into virions, and nucleolin promotes the infectivity of HIV-1. Our results suggest that an empty particle which contains neither nucleolin nor the genomic RNA is eliminated during the budding process, and this mechanism is beneficial for escape from the host immune response against HIV-1.     

B cell receptor-mediated Syk-independent activation of phosphatidylinositol 3-kinase,Ras, and mitogen-activated protein kinase pathways

The Syk tyrosine kinase is a key molecule in the development of the B cell lineage and the activation of B lymphocytes after Ag recognition by the B cell Ag receptor (BCR). Several genetic studies with chicken B cells have reported that the recruitment of Syk by BCR is essential for activation of a cascade of signaling molecules including phosphatidylinositol 3-kinase, mitogen-activated protein kinases, Ras signaling pathways, phospholipase C-gamma2 activation, and calcium mobilization. The identification of a Syk-deficient mouse IIA1.6/A20 B cell line provided us the opportunity to investigate Syk-mediated signaling in mouse. Surprisingly, phosphatidylinositol 3-kinase, Ras, and mitogen-activated protein kinases were activated upon BCR cross-linking in these Syk-deficient mouse B cells, whereas, as expected from results obtained in chicken B cells, phospholipase C-gamma2 activation and calcium mobilization were impaired as well as the NF-kappaB pathway. These results indicate that BCR signaling is not strictly dependent on Syk expression in mouse IIA1.6/A20 B cells. Thus, B lymphocyte activation may be initiated by Syk-dependent and Syk-independent signaling cascades.     

Conjugation of various acridines to DNA for site-selective RNA scission by lanthanide ion

Three types of DNA conjugates having 9-acridinecarboxamide, 9-aminoacridine, and 9-amino-6-chloro-2-methoxyacridine at the 5'-ends were synthesized and used for site-selective RNA scission together with another unmodified DNA and Lu(III) ion. The target phosphodiester linkages in the substrate RNA were selectively and efficiently activated and were hydrolyzed by free Lu(III) ion. The conjugate bearing 9-amino-6-chloro-2-methoxyacridine was the most active. However, its duplex with the substrate RNA was almost as stable as that of the 9-aminoacridine-bearing conjugate, which was much less active for the RNA activation. The 9-acridinecarboxamide-bearing conjugate was only marginally active. The substituents on the acridine groups in these conjugates positively participate in the present RNA activation, probably by fixing the orientation of the acridine rings.     

Concanavalin A Acts as a Factor in Establishing the Dorso-Ventral Gradient in the Ventral Mesoderm of Newt Gastrula Embryos1

Con A induced dorsal differentiation in the ventral mesoderm of Cynops gastrula embryo. This process apparently requires a certain amount of Con A to be internalized as supported by the following evidence: 1) Oligomannose-type oligosaccharide, a potent inhibitor of Con A, considerably inhibited dorsalization of ventral mesoderm by Con A. The incorporation of ¹²⁵I-Con A into the ventral mesoderm was greatly inhibited by this sugar. 2) Sepharose-immobilized Con A did not dorsalize the ventral mesoderm. Con A-induced dorsalization was found to be concentration-dependent. Microautoradiograms of ¹²⁵I-Con A-treated ventral mesoderm suggest that the target site (some receptor molecules) of Con A exists inside the cell. Con A is the first pure substance reported to mimic the two properties of the organizer—neural induction of the competent ectoderm and dorsalization of the ventral mesoderm. In neural induction, Con A acts on the cell surface, while Con A apparently needs to be internalized to trigger dorsal differentiation. Interestingly, Con A-dorsalized ventral mesoderm acquired the neural inducing function of the organizer within the early phase of dorsalization.     

Topographic pattern of the rearrangement of the dystrophin gene in Japanese Duchenne muscular dystrophy

To compare the frequency and distribution of rearrangements in the dystrophin gene in Duchenne muscular dystrophy (DMD) between Japanese DMD patients and those in North America and Europe, Southern blot analyses of the dystrophin gene were carried out in 88 probands classified as DMD. Gene rearrangements were found in 61 (69%) subjects, and they were composed of partial gene deletions in 53 (60%) probands and partial duplications in 7 (8%) probands. A total deletion of the gene was found in 1 (1%) patient. Among 53 patients with deletions, 34 (64%) had breakpoints between introns 44 and 52 and 7 (13%) had breakpoints between introns 2 and 11. Both the frequency and the distribution of gene rearrangements found in this study were similar to those reported in North America and Europe. These data suggest that there are no ethnic or racial differences in the frequency and distribution of rearrangements thought to be caused by similar mechanisms in the dystrophin gene in all human racial groupings.     

Isolation and characterization of two tightly linked catalase genes from castor bean that are differentially regulated

Two catalase genes,cat1 andcat2, have been isolated from the castor bean genome. They were located in the same direction on a chromosome at a distance of 2.4 kb,cat1 being on the downstream side ofcat2. The two genes contained introns at the same positions except that one of the 7 introns incat1 is missing incat2 and the corresponding introns differed in size and sequence between the two genes. The translated regions of the two genes had the same number of nucleotides and exhibited 81.3% nucleotide sequence identity. In addition to introns, the nucleotide sequences of the 5-and 3-flanking regions are highly divergent between the two genes. In etiolated seedlings,cat1 mRNA was present abundantly in endosperms and cotyledons and only in a small amount in roots. Thecat1 mRNA could not be detected in hypocotyls. By contrast,cat2 mRNA is most abundant in hypocotyls and roots, while endosperms and cotyledons contained only low levels ofcat2 mRNA. Although neithercat1 norcat2 mRNA could be detected in dry seeds, both mRNAs showed temporal accumulation in the endosperm in response to germination. These results suggest that expression of two tightly linked catalase genes of castor bean,cat1 andcat2, are differentially regulated during development.