Methylene Blue Reduced Abnormal Tau Accumulation in P301L Tau Transgenic Mice

In neurodegenerative disorders, abnormally hyperphosphorylated and aggregated tau accumulates intracellularly, a mechanism which is thought to induce neuronal cell death. Methylene blue, a type of phenothiazine, has been reported to inhibit tau aggregation in vitro. However, the effect of methylene blue in vivo has remained unknown. Therefore, we examined whether methylene blue suppresses abnormal tau accumulation using P301L tau transgenic mice. At 8 to 11 months of age, these mice were orally administered methylene blue for 5 months. Subsequent results of Western blotting analysis revealed that this agent reduced detergent-insoluble phospho-tau. Methylene blue may have potential as a drug candidate for the treatment of tauopathy.     

Escherichia coli small heat shock proteins, IbpA and IbpB, protect enzymes from inactivation by heat and oxidants.

To examine functions of two small heat shock proteins of Escherichia coli, IbpA and IbpB, we constructed His-IbpA and His-IbpB, in which a polyhistidine tag was fused to the N-terminals. Both purified His-IbpA and His-IbpB formed multimers, which have molecular masses of about 2.0-3.0 MDa and consist of about 100-150 subunits. They suppressed the inactivation of several enzymes including citrate synthase and 6-phosphogluconate dehydrogenase by heat, potassium superoxide, hydrogen peroxide and freeze-thawing, but not the inactivation of glyceraldehyde-3-phosphate dehydrogenase by hydrogen peroxide. Both His-IbpA and His-IbpB suppressed enzyme inactivation by various treatments and were also found to be associated with their non-native forms. However, both His-IbpA and His-IbpB were not able to reactivate enzymes inactivated by heat, oxidants or guanidine hydrochloride. When heated to 50 degrees C, each multimeric form of His-IbpA or His-IbpB was dissociated to form a monomer for His-IbpA, and an oligomer of about one-quarter size for His-IbpB. These structural changes were reversible, as both heated proteins regained the multimeric structures after incubation at 25 degrees C. However, when exposed to hydrogen peroxide or potassium superoxide, the large multimeric forms of His-IbpA and His-IbpB were maintained. The results suggest that His-IbpA and His-IbpB suppress the inactivation of enzymes and bind non-native proteins to protect their structures from heat and oxidants.     

Mode of bactericidal action of silver zeolite and its comparison with that of silver nitrate

The properties of the bactericidal action of silver zeolite as affected by inorganic salts and ion chelators were similar to those of silver nitrate. The results suggest that the contact of the bacterial cell with silver zeolite, the consequent transfer of silver ion to the cell, and the generation of reactive oxygen species in the cell are involved in the bactericidal activity of silver zeolite.     

Endothelial dysfunction as a cellular mechanism for vascular failure

The regulation of vascular tone, vascular permeability, and thromboresistance is essential to maintain blood circulation and therefore tissue environments under physiological conditions. Atherogenic stimuli, including diabetes, dyslipidemia, and oxidative stress, induce vascular dysfunction, leading to atherosclerosis, which is a key pathological basis for cardiovascular diseases such as ischemic heart disease and stroke. We have proposed a novel concept termed "vascular failure" to comprehensively recognize the vascular dysfunction that contributes to the development of cardiovascular diseases. Vascular endothelial cells form the vascular endothelium as a monolayer that covers the vascular lumen and serves as an interface between circulating blood and immune cells. Endothelial cells regulate vascular function in collaboration with smooth muscle cells. Endothelial dysfunction under pathophysiological conditions contributes to the development of vascular dysfunction. Here, we address the barrier function and microtubule function of endothelial cells. Endothelial barrier function, mediated by cell-to-cell junctions between endothelial cells, is regulated by small GTPases and kinases. Microtubule function, regulated by the acetylation of tubulin, a component of the microtubules, is a target of atherogenic stimuli. The elucidation of the molecular mechanisms of endothelial dysfunction as a cellular mechanism for vascular failure could provide novel therapeutic targets of cardiovascular diseases.     

Interactions between the Nucleus and Cytoplasmic Organelles during the Cell Cycle of Euglena gracilis in Synchronized Cultures: I. Associations between the Nucleus and Chloroplasts at an Early Stage in the Cell Cycle under Photoorganotrophic Conditions (Part I)

At an early stage in the cell cycle of Euglena gracilis Z, synchronizedunder 10-h light : 14-h dark alternations in an organic medium,the conjoined chloroplasts that formed made up a single giantbody that came close to the nucleus, covering most of the nuclearperiphery. Three different types of association between thesetwo organelles were observed. In one the outer membrane of thenuclear envelope was in contact, in some narrow regions, withthe chloroplast membrane, the site of contact being filled withdense material. A chromosome in the unfolded, fibrillar structurewas very close to the site of contact, the extreme end of thefibril touching the inner membrane of the nuclear envelope.When cells from the culture used above were stained with DAPIand examined under a fluorescence microscope, chloroplast nucleoidsin the giant body appeared to form, at least in part, a threadwith branchings, and some tips of the branchings came closeto the site of contact with the nucleus. In the second type of association, which was rare, part of thenuclear envelope protruded into the chloroplast, and the siteof contact was filled with dense material. A chromosome wasnear the site of this protrusion. In the third type of chloroplast-nucleusassociation the ER was continuous with the outer membrane ofthe nuclear envelope at one end and in contact with the chloroplastmembrane, at the other end. ¹This work was reported at the 48th Annual Meeting of the BotanicalSociety of Japan in Kyoto, October, 1983. (Received March 14, 1984; Accepted June 27, 1984)     

Regulation of Protochlorophyll(ide) Levels in Dark-Grown Non-Dividing Euglena 3. Proplastid Structure during Loss and Regeneration of Protochlorophyll(ide)

Cells of Euglena gracilis Klebs var. bacillaris Cori growingin darkness on a complete medium have small undifferentiatedproplastids. On transfer to an incomplete (resting) medium indarkness, the cells cease division within 72 h. During thistime the proplastid expands and several prothylakoids and prolamellarbodies develop even though phototransformable protochlorophyll(ide)[PT-Pchl(ide)] is decreasing. As PT-Pchl(ide) decreases furtherand reaches a stable plateau after 4–5 more days in darkness,the proplastid structure becomes highly reduced. Forty minutesof light plus a one h dark period, or addition of glutamateor malate for 7 h does not change the proplastid structure significantlyeven though PT-Pchl(ide) returns to the level found in growingcells. Upon prolonged incubation in darkness after light treatment(72 h) an expanded proplastid containing prothylakoids, prolamellarbodies and membrane whorls with mitochondria in close associationis seen; most of the cellular paramylum is lost during thisperiod leaving cavities in the cytoplasm. Without light, prolongedincubation in darkness (72 h) with malate leads to accumulationof cellular paramylum but no change in proplastid structurewhile prolonged treatment with glutamate (72 h) allows the formationof a few prothylakoids but no prolamellar bodies. ¹Supported by Grants GM 14595 from the National Institutes ofHealth. ²Permanent address: Department of Microbiology, Tokyo MedicalCollege, 6-1-1 Shinjuku, Tokyo 160, Japan. ³Abraham and Etta Goodman Professor of Biology. (Received July 23, 1983; Accepted September 22, 1983)     

Participation of Hydrogen Peroxide in the Inactivation of Calvin-Cycle SH Enzymes in SO2-Fumigated Spinach Leaves

In SO₂-fumigated spinach leaves under light, chloroplast SHenzymes, glyceraldehyde-3-phosphate dehydrogenase (NADP-GAPD)(EC 1.2.1.13 [EC] ), ribulose-5-phosphate kinase (Ru5PK) (EC 2.7.1.19 [EC] )and fructose-1,6-bisphosphatase (FBPase) (EC 3.1.3.11 [EC] ) weremore remarkably inactivated than other chloroplast enzymes.Their activities recovered after removal of SO₂. The inactivationparalleled light-dependent CO₂-fixation in spinach leaves. Inilluminated chloroplasts isolated from SO₂-fumigated spinachleaves, NADP-GAPD and Ru5PK were more specifically in activatedthan other chloroplast enzymes. These two enzymes could be protectedfrom the inactivation by adding catalase. The NADP-GAPD inactivationwas suppressed by DCMU, cytochrome c or anaerobic conditions.By adding thiol compounds, the NADP-GAPD inactivation was dischargedand the activity increased. In chloroplasts or crude extractsfrom non-fumigated spinach leaves, NADP-GAPD and Ru5PK weremore strongly inhibited by externally added H₂O₂ than otherchloroplast enzymes. All results supported the idea that thesuppression of photosynthesis at the beginning of SO₂ fumigationwas caused by the reversible inhibition of chloroplast SH enzymewith H₂O₂. (Received October 7, 1981; Accepted June 16, 1982)     

Autolysis of Bacillus subtilis induced by monovalent cations

Summary Resting cell suspensions of seven Nocardia species catalyzed the production of 10-hydroxystearic acid from oleic acid. Nocardia cholesterolicum NRRL 5767 gave a good yield with optimum conditions at pH 6.5 and 40°C. Yields exceeding 90% can be obtained within 6 h with 0.1 g cells (dry weight) and 178 mg oleic acid in 10 ml of 0.05 M sodium phosphate buffer (pH 6.5). In addition, minor amounts of 10-ketostearic acid were formed as a by-product. The reaction proceeded via hydration of the double bond as shown by labeling experiments with deuterium oxide and ¹⁸O-labeled water. The system was specific for fatty acids with cis unsaturation at the 9 position.A part of this paper was presented at a poster session at the World Conference on Biotechnology for the Fats and Oils Industry, Hamburg, Federal Republic of Germany, September 1987, and at the 194th National American Chemical Society Meeting, New Orleans, September 1987RetiredThe mention of firm names or trade products does not imply that they are endorsed or recommended by USDA over other firms or similar products not mentioned