Ataru Kuroiwa

Inactivation of Lactobacillus Bacteriophage PL-1 by Microwave Irradiation

The effect of microwave irradiation on the survival of bacteriophage PL‐1, which is specific for Lactobacillus casei, was studied using a commercial 2,450 MHz microwave oven. The phages were inactivated by microwave irradiation according to almost first‐order reaction kinetics. The rate of phage inactivation was not affected by the difference in the continuous or intermittent irradiation, nor by the concentrations of phages used, but was affected by the volume of phage suspensions, which prevented the loss of generated heat. Microwave irradiation of phage suspensions produced a number of ghost phages with empty heads, but fragmentation of the tail was hardly noticed. The breakage of phage genome DNA was primarily caused by the heat generated by microwave irradiation, whereas the phage DNA was not affected by the same temperature achieved by heat from outside. Thus we concluded that the phage‐inactivating effect of microwave irradiation was mainly attributed to a thermal microwave effect, which was much stronger than a simple thermal exposure.

Free Radical-Mediated Tissue Injury in Acute Lung Allograft Rejection and the Effect of Superoxide Dismutase

BACKGROUND The role of monocytes and neutrophils is crucial during acute allograft rejection. They have the capacity to generate toxic reactive oxygen intermediates in response to specific agonists that may act as tissue destructive molecules. We examined the possibility of reactive intermediate-mediated tissue injury in acute lung allograft rejection, as well as the effect of superoxide dismutase. METHODS Allogenic (Brown Norway to F344) or syngenic (F344 to F344) rat left-lung transplantation was performed. Generation of reactive oxygen intermediates in peripheral blood was evaluated by the method of luminol-dependent chemiluminescence. Cell membrane phospholipid peroxidation in the graft was measured as malondialdehyde concentration. The third group of animals having allografts received bovine erythrocyte superoxide dismutase (5,000 U/kg intravenously every 12 hours after transplantation). RESULTS Relative chemiluminescence response in the allograft recipient to normal F344 was elevated on postoperative day 1 (257%), then decreased slightly on day 3 (156%) and was elevated again on day 7 (560%) as the process of rejection progressed. Allograft tissue malondialdehyde levels (248.37 +/- 112.35 nM/whole lung, n = 6; p < 0.05 by Students t test) were higher than isograft levels (139.29 +/- 35.93 nM/whole lung, n = 6) on day 7. Superoxide dismutase treatment significantly ameliorated the histologic degree of rejection on day 7. CONCLUSIONS These results demonstrate the tissue destructive activity of reactive oxygen intermediates during lung allograft rejection. To scavenge free radicals may be a useful therapeutic modality in the management of acute lung allograft rejection.

Study on Nonspecific Immunity in Pregnant Women: II. Effect of Hormones on Chemiluminescence Response of Peripheral Blood Phagocytes

ABSTRACT: To analyze the mechanisms of increased nonspecific immunity in pregnant women, the effect of various hormones on the phagocytic activity was estimated by a luminol‐dependent chemiluminescence (CL) response during phagocytosing opsonized zymosan. The CL response of whole blood supplemented with exogenous human chorionic gonadotropin (hCG) increased significantly in all the male and female subjects and pregnant women. An approximate two‐ to fourfold increase was observed in comparison with the unsupplemented control in each subject at concentrations ranging from 1 to 1,000 IU/ml after 48 h of incubation (P < 0.05). Progesterone slightly stimulated the CL response in female subjects only, but had no effect on male and pregnant women. Estradiol (E2) did not stimulate the CL response in any subject.

Changes of surface hydrophobicity and charge of Staphylococcus aureus treated with Sub-MIC of antibiotics and their effects on the chemiluminescence response of phagocytic cells

The effects of the sub-MIC of antibiotics on the surface hydrophobicity and charge of Staphylococcus aureus were examined by the contact angle method and by microscopic electrophoresis, and the production of oxygen-derived radicals by mouse peritoneal macrophages was measured by a luminol-chemiluminescence assay. The treatment of the bacterial cells with antibiotics induced an increase in hydrophobicity and a decrease in the negative charge of the bacterial surface. The chemiluminescence of the macrophages stimulated by S. aureus treated with antibiotics was significantly higher than that obtained with the untreated bacterial cells. These findings suggest that the antibiotics caused an increase in the hydrophobicity and a decrease in the negative charge of the surface of S. aureus, resulting in the enhancement of nonopsonic phagocytosis of S. aureus by macrophages.

Mechanisms of in vivo generation of cytotoxic activity against allograft: 1. Local differentiation of mature cytotoxic T lymphocytes in rejection of allogeneic lymphocytes

Abstract Although cytotoxic activity was not detected within the spleen and regional lymph nodes from mice immunized sc with allogeneic lymphocytes, such activity was detected consistently in glass-nonadherent and anti-θ-sensitive peritoneal exudate cells (PE cells) from Day 5 after immunization and reached a maximum by Day 7. Immunized spleen cells developed cytotoxic T lymphocytes (CTLs) earlier and more effectively than normal spleen cells when transferred ip into X-irradiated syngeneic normal mice together with immunizing antigen, while they did not become cytotoxic when transferred without antigen. These results suggest that spleen and lymph node cells which may have differentiated into some transitional state by in vivo immunization may differentiate into mature CTLs, following direct contact with antigen at the site of graft. CTLs generated there appear to be responsible for the rejection of allogeneic lymphocytes. Cytotoxicity of PE cells was also generated in X-irradiated mice and augmented cytotoxicity was generated by treatment with cyclophosphamide.

Characterization of Pseudomonas paucimobilis FP2001 Which Forms Flagella Depending upon the Presence of Rhamnose in Liquid Medium

A bacterial strain FP2001 isolated from the exudate of land reclaimed for municipal waste was identified as Pseudomonas paucimobilis. Cells of strain FP2001 were mobile by means of polar monotrichous flagellum, only when rhamnose was added as a carbon source in the liquid medium. The replacement of rhamnose by arabinose, galactose, glucose or xylose did not lead to the formation of flagella.

A temperate phage with cohesive ends induced by mitomycin C treatment of Lactobacillus casei

SummaryA temperate phage, named PL-2, was induced from Lactobacillus casei ATCC 27092 by mitomycin C treatment of the cells at exponential growth phase. The phage had an isometric head of 45 nm in diameter and a flexible, non-contractile tail, 150 nm long and 10 nm wide, with a sharp tip. Along the tail axis, about 40 regularly spaced striae were seen. The phage DNA had complementary cohesive ends. The restriction enzyme map of the DNA was constructed by using 13 different restriction endonucleases. The size of the DNA was 35.2 kb, 83% in size of that of phage PL-1 lytic for the same Lb. casei strain.

Effects of qing-fei-tang on the airway inflammation and clearance.

Qing-Fei-Tang, a Chinese blended medicine, inhibited the release of slow reacting substance of anaphylaxis (SRS-A) from passively sensitized guinea pig lung after antigen challenge. Qing-Fei-Tang also suppressed the chemiluminescence of oxygen radicals when healthy human leukocytes were stimulated by opsonized zymosan. In rabbits, Qing-Fei-Tang increased the output volume and fatty acid contents in respiratory tract fluid. In the bronchitic rabbits, 6 weeks administration of Qing-Fei-Tang restored the decreased amount of saturated fatty acid in the sputa, and histological examinations revealed an amelioration of the inflammation of lung tissues. In pigeons, Qing-Fei-Tang facilitated tracheal mucociliary transport. Accordingly, Qing-Fei-Tang seems to exert effectiveness via its multiple mechanisms.

Electron microscope studies on the intracellular growth of PL-1 phage of Lactobacillus casei.

Ultrathin sections of the cells of Lactobacillus casei infected with or without PL‐1 phages were observed by the rapid‐freezing and substitution‐fixation method. Phage‐head‐like particles were first observed in the nuclear region. The region was seen more widely dispersed in the cytoplasm than that observed by the conventional chemical fixation method. The features of cells just broken open by the infected phages were observed by the sedimentation method devised by us. The bursting occurred in more than one place in the cells with liberation of progeny phages.

Graft-versus-host reactions against H-Y antigen.

Spleen cells of female C57BL/6 mice, preimmunized to male histocompatibility antigen, elicited splenomegaly in adult male recipients and caused mortality of the newborn recipients. These cells, upon stimulation in vitro with the male antigen, were cytotoxic to male target cells.