Biologically active oligodeoxyribonucleotides. Part 12: N2-methylation of 2'-deoxyguanosines enhances stability of parallel G-quadruplex and anti-HIV-1 activity

2'-Deoxyguanosine residues of a 3',5'-end-modified hexadeoxyribonucleotide (R-95288) with anti-HIV-1 activity were substituted with N2-methyl-2'-deoxyguanosine (m2dG). These modified oligodeoxyribonucleotides (ODNs) showed a 2-fold higher activity than R-95288. Also, the CD spectra of these ODNs indicated that the m2dG modification stabilized the tertiary structure of the G-quadruplex.     

Effects of 5alpha-androst-16-en-3alpha-ol on the pulsatile secretion of luteinizing hormone in human females

We examined the effects of 5alpha-androst-16-en-3alpha-ol (3alpha-androstenol) on pulsatile luteinizing hormone (LH) secretion in human females. The frequency of the LH pulse in the follicular phase was decreased by exposing the women to 3alpha-androstenol.     

Effect of antibiotics, levofloxacin and fosfomycin, on a mouse model with Escherichia coli O157 infection

There have been some reservations about the treatment of enterohemorrhagic Escherichia coli (EHEC) infection with antibiotics to prevent the occurrence of hemolytic uremic syndrome (HUS). However, the administration of antimicrobial agents for EHEC infection is under discussion. Therefore, we used an experimental mouse model to assess the advantage/disadvantage of two major antibiotics, levofloxacin (LVFX) and fosfomycin (FOM). Germ-free IQI mice were inoculated with EHEC O157 strain EDL931 or #7. Bacteria colonized feces at 10(9)-10(10) CFU/g, and Shiga toxins (STXs) were detected in the feces. From 1 day after infection, mice were assigned to LVFX (20 mg/kg) once daily or FOM (400 mg/kg) once daily. A significant decrease in overall mortality was observed after treatment of LVFX, with EHEC disappearing immediately from the feces of mice. FOM also reduced mortality for one strain, the STX level decreased gradually. LVFX exhibited higher therapeutic efficacy than FOM. Strain differences were observed in the model during the treatment.     

Hepatic zinc response via metallothionein induction after tumor transplantation

Based on previous findings that liver zinc and metallothionein (MT) levels increase after tumor transplantation, zinc metabolism in tumor-bearing mice was studied to clarify the role of zinc-MT in host defense systems. Zinc in the hepatic cytosolic MT fraction did not increase in tumor-bearing mice fed a zinc-deficient diet, suggesting that dietary zinc is necessary for apo-MT induction in the liver after tumor transplantation and is then incorporated into the apo-MT. When (65)ZnCl(2) was intravenously injected, liver (65)Zn levels in the tumor-bearing mice were higher than those in control mice for 72 h after the injection. Pancreatic and blood (65)Zn levels in tumor-bearing mice were lower than those in controls for 24 h (pancreas) and 6 h (blood) after the injection. These findings indicate that the hepatic zinc response via MT induction influences zinc metabolism in the body after tumor transplantation. Moreover, (65)Zn uptake in the liver of MT-deficient tumor-bearing mice was lower than that in control tumor-bearing mice 1 h after injection. (65)Zn uptake in the tumor and blood (65)Zn levels in the MT-deficient tumor-bearing mice were higher than those in the control tumor-bearing mice. Tumor weight increased more in MT-deficient mice than in control mice. The formation of zinc-MT in the liver of tumor-bearing mice might decrease blood zinc availability for tumors and other tissues, such as the pancreas.     

Increase of hybrids in yeast electrofusion by mitochondrial mutations

Yeast mitochondria were found to affect the zeta-potential of protoplasts, resulting in electrofusion of membrane behavior. For modeling purposes, two fusion systems were investigated: (1) parent yeasts of Saccharomyces cerevisiae G706 (rho(+)) x O708-11-16A (rho(+)), with zeta-potentials of -10 to -27 mV and -28 to -45 mV, depending on MgCl(2) concentration in the medium, respectively; and (2) parent yeasts of S. cerevisiae G706-1 (rho(-)) x O708-11-16A (rho(+)), with zeta-potentials of -30 to -60 mV, depending on MgCl(2). Yields of the hybrids in system (2) were over 100-fold higher than those in system (1). Thus, regulation of yeast electrofusion was found to be possible by mitochondrial mutations.     

Polyurethane membrane as an efficient immobilization carrier for high-density culture of rat hepatocytes in the fixed-bed reactor

A fixed-bed bioreactor with a polyurethane membrane (PUM) as a cell-supporting material was developed for high-density culture of rat hepatocytes. The PUM has a heterogeneous porous structure of micropores (pore size <100 microm) and macropores (pore size >100 microm) with a porosity of 90%. One important feature of a PUM is that the macropores have finger-like structures and their diameters gradually decrease from the upper to the lower layer of the PUM. Most rat hepatocytes were readily immobilized in the micropores of PUM. Immobilized cell densities of 1-3 x 10(7) cells/cm(3) PUM were achieved within 5 min by natural downflow of cell suspension and their immobilization efficiencies were more than 99%. Using a syringe pump, a cell density of 5 x 10(7) cells/cm(3) PUM was achieved with more than 96% immobilization efficiency. Perfusion cultures using this reactor were performed for 7 days without cell leakage. The optimal cell density for albumin secretion was between 2 x 10(7) and 3 x 10(7) cells/cm(3) PUM. Albumin secretion in the perfusion culture was maintained for a relatively long period of time when compared to that in the monolayer culture. The rate of albumin secretion in the perfusion culture was about 50% of that in monolayer culture. Hepatocytes immobilized in PUM were slightly aggregated, but they maintained spherical form individually even after 7 days of cultivation. The above results show that PUM is a promising cell-supporting material for efficient immobilization of high cell density of hepatocytes.     

Development of quadrupedal locomotion on level surfaces in Japanese macaques

Longitudinal comparisons of high-speed quadrupedal locomotion on level surfaces were made on 4 infant Japanese macaques (Macaca fuscata) with normal mother-infant relationships. Compared to adults, infants exhibited considerable variation in each step of locomotion. Braking components of foot force tended to be larger in the forelimb than in the hindlimb during the infant stage of development. Conversely, accelerating components were larger in the hindlimb than in the forelimb. In 1- and 2-month-old infants, vertical components in the hindlimb were not significantly larger than those of the forelimb. Fore- and hindlimb differentiation in infant Japanese macaques resembles that of adult macaques even at this early stage of development.     

Enhancing effect of saccharides on the mutagenicity of 2-chloro-4-methylthiobutanoic acid

The mutagenicity of 2-chloro-4-methylthiobutanoic acid (CMBA), a nitrite-treated Sanma fish mutagen, in Salmonella typhimurium TA100 was enhanced by addition of D-glucose during the CMBA-treatment. Several other monosaccharides also enhanced the mutagenicity of CMBA, and the order of the enhancing potency was found to be D-mannose, D-glucose>D-fructose, D-ribose, D-galactose. A disaccharide, maltose, showed only little enhancement. No enhancement was found with L-glucose. We investigated whether saccharides affect uptake of [methyl-14C]CMBA into S. typhimurium TA100. Saccharides which enhanced CMBA-induced mutagenesis increased the uptake. L-Glucose did not enhance the uptake. There was good correlation between the enhanced mutagenesis and increased radioactivity in Salmonella, suggesting that the enhancing effect of monosaccharide on the CMBA-induced mutagenesis results from the enhanced uptake of the mutagen into bacteria.