Adherence of Protease-Deficient Mutants of Pseudomonas aeruginosa to a Rabbit Cornea Cell Line (SIRC) Cells

Seven protease-deficient mutants were isolated from Pseudomonas aeruginosa strain IFO 3455 which was mutagenized with nitrosoguanidine. Characterization of these mutants in vitro revealed that all mutants showed pleiotropic changes in the production of other extracellular substances. Among the mutants, two were chosen for a bacterial adherence test to Rabbit Cornea Cell Line (SIRC) cells. One mutant (IFO 3455-2) completely lost its protease activity. Another (IFO 3455-3) retained a low protease activity and was relatively similar to the parental strain with respect to extracellular products except for protease. Both mutants gave not a marked but a slight decrease of adherence as compared with the parental strain. This finding suggests that besides protease more factors are involved in the adhesion between P. aeruginosa and SIRC cells

Physical and Chemical Factors Affecting the Adherence of Pseudomonas aeruginosa to a Rabbit Cornea Cell Line (SIRC) Cells

Adherence of Pseudomonas aeruginosa to SIRC cells was examined by the use of 14C-lysine labeled organisms. Pretreatment of P. aeruginosa with heating, 3% formaldehyde, or ultraviolet caused a significant decrease in adherence to SIRC cells, whereas that with lipase, hyaluronidase, trypsin or protease did not. Treatment of SIRC cells with trypsin, protease, lipase or neuraminidase did not influence the adherence of P. aeruginosa to the cell. Treatment of P. aeruginosa with mannose or galactose inhibited the adherence, while that with fructose, lactose or glucose did not. Treatment of SIRC cells with galactosidase or mannosidase reduced the adherence of the organism. No correlation was demonstrated between the adhering ability and hydrophobicity of P. aeruginosa. The results suggest that both the viability in bacterial site and mannose and/or galactose molecules in cellular site are closely connected with the adherence of P. aeruginosa to SIRC cells

Spontaneous strain due to ferroquadrupolar ordering in UCu2_2Sn

The ternary uranium compound UCu$_2$Sn with a hexagonal ZrPt$_2$Al-type structure shows a phase transition at 16 K. We reported previously that huge lattice-softening is accompanied by the phase transition, which originates from ferroquadrupolar ordering of the ground state non-Kramers doublet $\Gamma_5$. A macroscopic strain, which is expected to emerge spontaneously, was not detected by powder X-ray diffraction in the temperature range between 4.2 and 300 K. To search the spontaneous strain, we have carried out thermal expansion measurements on a single-crystalline sample along the $a$, $b$ and $c$ axes using a capacitance technique with the resolution of $10^{-8}$. In the present experiment, we found the spontaneous $e_{xx} - e_{yy}$ strain which couples to the ground state doublet $\Gamma_5$. The effect of uniaxial pressure along the $a$, $b$ and $c$ axes on the transition temperature is also discussed.Comment: 4 pages, 5 figures, submitted to Phys. Rev.

Micro Scanning Laser Range Sensor for Planetary Exploration

This paper proposes a new type of scanning laser range sensor for planetary exploration. The proposed sensor has advantages of small size, light weight, and low power consumption with the help of micro electrical mechanical systems technology. We are in the process of developing a miniature two dimensional optical sensor which is driven by a piezoelectric actuator. In this paper, we present the mechanisms and system concept of a micro scanning laser range sensor

Destruxin E Decreases Beta-Amyloid Generation by Reducing Colocalization of Beta-Amyloid-Cleaving Enzyme 1 and Beta-Amyloid Protein Precursor

Alzheimer-disease-associated beta-amyloid (A beta) is produced by sequential endoproteolysis of beta-amyloid protein precursor (beta APP): the extracellular portion is shed by cleavage in the juxtamembrane region by beta-amyloid-cleaving enzyme (BACE)/beta-secretase, after which it is cleaved by presenilin (PS)/gamma-secretase near the middle of the transmembrane domain. Thus, inhibition of either of the secretases reduces A beta generation and is a fundamental strategy for the development of drugs to prevent Alzheimer disease. However, it is not clear how small compounds reduce A beta production without inhibition of the secretases. Such compounds are expected to avoid some of the side effects of secretase inhibitors. Here, we report that destruxin E (Dx-E), a natural cyclic hexadepsipeptide, reduces A beta generation without affecting BACE or PS/gamma-secretase activity. In agreement with this, Dx-E did not inhibit Notch signaling. We found that Dx-E decreases colocalization of BACE1 and beta APP, which reduces beta-cleavage of beta APP. Therefore, the data demonstrate that Dx-E represents a novel A beta-reducing process which could have fewer side effects than secretase inhibitors. Copyright (C) 2009 S. Karger AG, Base