Regions of the lipopolysaccharide of Pseudomonas aeruginosa essential for antitumor and interferon-inducing activities.

Resistance against ascites tumor development and interferon-inducing activity were demonstrated in lipopolysaccharide derived from the protein-lipopolysaccharide complex obtained from an autolysate of Pseudomonas aeruginosa. Lipid A obtained from the lipopolysaccharide was sufficient to induce interferon in vitro but no antitumor activity was found if lipid A or the polysaccharide derived from lipopolysaccharide was injected into the animal. Chemical modification of the polysaccharide portion or deacylation of the lipopolysaccharide also diminished antitumor activity. In contrast, interferon was induced by these incomplete lipopolysaccharides. These results indicate that both the lipid A portion and covalently linked polysaccharide are necessary for the inhibition of ascites tumor development, whereas incomplete lipid A with amide-linked fatty acids is sufficient to induce interferon in vitro.     

Changes in the organization and biosynthesis of cell surface acidic sugars during the phytohemagglutinin-induced blast formation of human T-lymphocytes

Use of cell electrophoresis combined with specific enzymes and varying ionic strength revealed a topological change of acidic sugars in lymphocyte membrane treated with a T-cell mitogen, phytohemagglutinin (PHA). The suggested alterations were an early translocation of hyaluronic acid to the cell periphery within 15 min of PHA addition and, 4 h later, the appearance of chondroitin sulphate in T-lymphocytes, but not in B-lymphocytes. As the contribution of chondroitin sulfate to the electrophoretic mobility increased with time up to 24 h, that of sialic acid decreased conversely. Several agents which block blast formation (2 mM ethylene glycol bis-β-aminoethylethyl-N,N,N′,N′-tetraacetic acid, 2 × 10⁻⁷ M ouabain, 0.1 μg/ml colchicine and 1 μg/ml cytochalasin B) also blocked the translocation of hyaluronic acid at the same concentrations. Chemical analysis of [¹⁴C]glycosaminoglycans by means of gel filtration followed by paper chromatography revealed a four-fold enhancement of the biosynthesis of chondroitin sulfate C after PHA stimulation. The presence of chondroitin sulfate in the cell periphery was also detected electrophoretically in T-cell type leukemia cells (MOLT-4B). These results suggest that the reorganization of glycosaminoglycans may be one of the membrane changes associated with blast formation of lymphocytes.     

Recovery from radiation-induced decrease in cell membrane charge by added adenosine triphosphate and its modification by colchicine or cytochalasin B.

Cell electrophoretic mobility of rat erythrocyte decreased with time after 3000 R X-irradiation without spontaneous recovery. On addition of 10^?4M ATP to the irradiated cells, recovery was observed within 10 minutes. Washing out of ATP and subsequent incubation for 1 hr resulted in the return of mobility to the low level. Preincubation with 0.1 μg/ml colchicine for 15 minutes or 1 μg/ml cytochalasin B for 30 min completely blocked the reversible effect of ATP on electrophoretic mobility. These results suggest the existence of tubulin-like polymerizing protein in the cytoplasmic membrane and changes in its conformation induced both by X-irradiation and by added ATP.     

Immunogenicity of lysozyme derivatives lipid-conjugated to various degrees in mice treated with and without cyclophosphamide: dissociation of delayed-type hypersensitivity and helper function.

Lysozyme and a series of its lipid-conjugated derivatives without adjuvant were examined in mice for their abilities to induce delayed-type hypersensitivity (DTH), helper T-cell activity, and antibody formation. In addition, the effect of cyclophosphamide (CY) on the immune responses was assessed in mice immunized with these lysozyme derivatives. Precipitated lysozyme without lipid conjugation was a good inducer of both antibody and DTH responses. Lipid conjugation to lysozyme to intermediate degrees readily caused the failure only in inducing the antibody response. As lysozyme was lipid-conjugated more heavily, DTH response was also reduced and finally abolished. In contrast, the helper activity was little affected by any degree of lipid conjugation. These results indicate that the helper T-cell activity was dissociated from the both DTH response and the antibody production. CY pretreatment extensively enhanced DTH response induced by such lipid-conjugated derivatives that failed to induce antibody response. Furthermore, CY pretreatment in doses in a wide range enhanced not only DTH response but also antibody formation. It is, therefore, concluded that the enhancement of DTH response by CY does not necessarily entail suppression of antibody formation.     

T-maze Forced Alternation and Left-right Discrimination Tasks for Assessing Working and Reference Memory in Mice

Forced alternation and left-right discrimination tasks using the T-maze have been widely used to assess working and reference memory, respectively, in rodents. In our laboratory, we evaluated the two types of memory in more than 30 strains of genetically engineered mice using the automated version of this apparatus. Here, we present the modified T-maze apparatus operated by a computer with a video-tracking system and our protocols in a movie format. The T-maze apparatus consists of runways partitioned off by sliding doors that can automatically open downward, each with a start box, a T-shaped alley, two boxes with automatic pellet dispensers at one side of the box, and two L-shaped alleys. Each L-shaped alley is connected to the start box so that mice can return to the start box, which excludes the effects of experimenter handling on mouse behavior. This apparatus also has an advantage that in vivo microdialysis, in vivo electrophysiology, and optogenetics techniques can be performed during T-maze performance because the doors are designed to go down into the floor. In this movie article, we describe T-maze tasks using the automated apparatus and the T-maze performance of α-CaMKII+/- mice, which are reported to show working memory deficits in the eight-arm radial maze task. Our data indicated that α-CaMKII+/- mice showed a working memory deficit, but no impairment of reference memory, and are consistent with previous findings using the eight-arm radial maze task, which supports the validity of our protocol. In addition, our data indicate that mutants tended to exhibit reversal learning deficits, suggesting that α-CaMKII deficiency causes reduced behavioral flexibility. Thus, the T-maze test using the modified automatic apparatus is useful for assessing working and reference memory and behavioral flexibility in mice.     

Impaired UTP-induced relaxation in the carotid arteries of spontaneously hypertensive rats

Uridine 5′-triphosphate (UTP) has an important role as an extracellular signaling molecule that regulates inflammation, angiogenesis, and vascular tone. While chronic hypertension has been shown to promote alterations in arterial vascular tone regulation, carotid artery responses to UTP under hypertensive conditions have remained unclear. The present study investigated carotid artery responses to UTP in spontaneously hypertensive rats (SHR) and control Wistar Kyoto rats (WKY). Accordingly, our results found that although UTP promotes concentration-dependent relaxation in isolated carotid artery segments from both SHR and WKY after pretreatment with phenylephrine, SHR exhibited significantly lower arterial relaxation responses compared with WKY. Moreover, UTP-induced relaxation was substantially reduced by endothelial denudation and by the nitric oxide (NO) synthase inhibitor N^G-nitro-L-arginine in both SHR and WKY. The difference in UTP-induced relaxation between both groups was abolished by the selective P2Y₂ receptor antagonist AR-C118925XX and the cyclooxygenase (COX) inhibitor indomethacin but not by the thromboxane-prostanoid receptor antagonist SQ29548. Furthermore, we detected the release of PGE₂, PGF_2α, and PGI₂ in the carotid arteries of SHR and WKY, both at baseline and in response to UTP. UTP administration also increased TXA₂ levels in WKY but not SHR. Overall, our results suggest that UTP-induced relaxation in carotid arteries is impaired in SHR perhaps due to impaired P2Y₂ receptor signaling, reductions in endothelial NO, and increases in the levels of COX-derived vasoconstrictor prostanoids.

     

Sulfurimicrobium lacus gen. nov., sp. nov., a sulfur oxidizer isolated from lake water,and review of the family Sulfuricellaceae to show that it is not a later synonym of Gallionellaceae

Archives of Microbiology - A facultatively anaerobic sulfur-oxidizing bacterium, strain skT11T, was isolated from anoxic lake water of a stratified freshwater lake. As electron donor for...     

Reduction of severe acute respiratory syndrome coronavirus-2 infectivity by admissible concentration of ozone gas and water

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is causing the global coronavirus disease 2019 (COVID-19) pandemic. Because complete elimination of SARS-CoV-2 appears difficult, decreasing the risk of transmission is important. Treatment with 0.1 and 0.05 ppm ozone gas for 10 and 20 hr, respectively, decreased SARS-CoV-2 infectivity by about 95%. The magnitude of the effect was dependent on humidity. Treatment with 1 and 2 mg/L ozone water for 10 s reduced SARS-CoV-2 infectivity by about 2 and 3 logs, respectively. Our results suggest that low-dose ozone, in the form of gas and water, is effective against SARS-CoV-2.