Various phenotypes of the resistance to aminoglycoside- and peptide-antibiotics of Mycobacterium tuberculosis strain H37Rv were produced by single- and/ or two-step selection of the parent strain. Mutants obtained by single-step selection with antibiotics were classified into ten phenotypes; one of single resistance, two of triple resistance, three of quadruple resistance, and four of sextuple resistance. There were two kinds of sextuple resistance (high resistance to enviomycin, viomycin, capreomycin, kanamycin, lividomycin, and paromomycin). One was isolated from the parent strain by single-step selection and could be eliminated by mutation to isoniazid resistance, the other was obtained by two-step selections and was not eliminated by mutation to isoniazid resistance. Interaction between mutation to streptomycin resistance and mutation to quadruple resistance (4R phenotype) was observed. Streptomycin resistance interfered with the formation of the 4R phenotype and produced a different phenotype, KR instead of the 4R phenotype. The existence of mutation of the 4R phenotype did not usually interfere with mutation to streptomycin resistance, but a small portion of the mutants with the 4R phenotype were altered in their phenotype from 4R to KR after addition of the mutation to streptomycin resistance. This effect of the mutation to streptomycin resistance was not observed in mutants which already had a mutation to klR phenotype (mutation to low concentrations of kanamycin only).

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The influence of intraperitoneal inoculation of live Salmonella typhimurium on carbohydrate and lipid metabolisms in mice was investigated at doses of 9.2 × 10⁷ cells, 1.9 × 10⁸ cells, and 3.8 × 10⁸ cells. The hepatic glycogen content in mice at 18 hr after the inoculation decreased in inverse proportion to an increase in the injection dose. The activities of hepatic phosphorylase and G-6-P_ase increased significantly after 2 hr, but after 18 hr the levels of both enzyme activities, especially G-6 P_ase, declined in inverse porportion to an increase in dose of viable cells administered to the mice. The levels of serum glucose and free fatty acids (FFA) in mice markedly decreased at doses of 1.9 × 10⁸ and 3.8 × 10⁸ cells after a transient rise at early stage (1 hr) after the injection. Marked hypertriglyceridemia was seen in infected mice. However, the activity in serum lipoprotein lipase (LPL) was reduced by an increase in the injection dose. The effect of intraperitoneal administration of viable cells on the serum triglyceride level was prevented in mice immunized with S. typhimurium endotoxin or administered with the anti-endotoxin serum. These results indicate that hypertriglyceridemia mainly results from the action of endotoxin in the pathogen. Serum lactate dehydrogenase (LDH) activity markedly increased at the dose of 3.8 × 10⁸ cells within 8-16 hr, and the infected mice exhibited a leakage of isozymes LDH-3 and 5 in the serum 16 hr post-inoculation.

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Production of extracellular amylase and protease in Vibrio parahaemolyticus was repressed by various carbohydrates present in the medium. In addition, the protease production was repressed very strongly by peptones or casamino acids. Cyclic adenosine 3', 5'-monophosphate (cyclic AMP) added exogenously could reverse the repression of amylase production, but not that of protease production irrespective of the “repressors” used. Mutants of V. parahaemolyticus, which resembled the reported cya (adenylate cyclase) and crp (cyclic AMP receptor protein) mutants of Escherichia coli and related organisms, were examined for the exoenzyme production. Amylase production in the mutants was defective, while their protease production was not defective, but rather accentuated as compared with that in the parental strain.
These findings strongly suggest that amylase production is subject to catabolite repression mediated by cyclic AMP, whereas protease production is controlled by a repression mechanism which mimics in part, but may be distinct from catabolite repression.

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Two β-lactamases were isolated from strains of Proteus species and purified, one from a strain of P. rettgeri and the other from a strain of P. inconstans. Each enzyme preparation gave a single protein band on polyacrylamide gel electrophoresis. Molecular weights of P. rettgeri and P. inconstans enzymes were found to be 42, 000 and 43, 000, and their isoelectric points pH 8.7 and 8.6, respectively. The two enzymes presented typical cephalosporinase profiles. Cefmetazole (CS-1170) and cefoxitin, both cephamycin antibiotics, not only resisted hydrolysis by both of the enzymes, but also inhibited their activities competitively. Rabbit antiserum against purified P. rettgeri enzyme inhibited the activity of both purified and crude enzyme preparations from other strains of P. rettgeri so far tested. None of the β-lactamases produced by other species of Proteus including P. inconstans was inhibited by the antiserum, thus showing that the purified cephalosporinase was of the species-specific type. The enzymological properties of the preparations were compared with those of β-lactamases derived from other gram-negative enteric bacteria.

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After intracerebral inoculation of mouse hepatitis virus, MHV-A59 strain, into 3- to 5-day-old Wistar rats, some survivors at 14 days postinoculation (p.i.) were found to lack the cerebral cortex and to have an accumulation of a considerable amount of cerebrospinal fluid. The virus titer in the brain increased exponentially after inoculation, reaching a maximum 4 to 6 days p.i. when immunofluorescence revealed virus-specific antigen within neurons in the cerebral cortex. A small amount of infectious virus was also detectable 14 days p.i. when the cerebral anomaly was evident. This brain malformation causing hydrocephalus was due to cerebral damage by viral infection.

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A mouse model for the study of postexposure prophylaxis of rabies was established. Mice injected intramuscularly with a street strain of rabies virus were significantly protected from death by five daily 0.2-ml doses of inactivated rabies vaccine of chick embryo cell culture origin initiated immediately or 3 hr after infection. In these mice, a large amount of circulating interferon was induced as early as 1 hr after the first dose of vaccine and lasted until at least 12 hr but no such amount of interferon was induced by additional doses of vaccine. Serum antibody was first detected in the mice on day 6. It was noted that some of the surviving mice manifested an ataxia or paralysis of the legs. Increasing mortality rates were shown in mice treated with decreasing doses of the vaccine. Passive protection tests using concentrated IgG and IgM antibodies with equivalent neutralization titers showed that IgG antibody gave total protection when given 24 hr before the infection, while it was almost totally ineffective in reducing the mortality when given 2 days or more after infection. IgM antibody did not protect the mice even when given 24 hr before infection. These results suggest that interferon production is more important than antibody production in the initial stages of protection by postexposure vaccination. However, the mechanisms of postexposure prophylaxis in this model could not be explained only by the interferon produced by the vaccine and the possible contributions of additional mechanisms were suggested.

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The mechanism of the action of tannic acid (TA) on Chikungunya virus (CHIKV) was investigated. Both infectivity and hemagglutination (HA) activity of CHIKV were reduced by treatment with TA in vitro. Aggregation of the TA-treated virus particles was observed by electron microscopy. The reaction was reversible, depending on the pH of the mixture. However, mere dilution of the TA-virus mixture or addition of other protein, such as bovine serum albumin, did not restore the lost infectivity. TA also suppressed the infectivity of RNA extracted from the virus and the HA activity of the viral membrane. The affinity between TA and CHIKV structural proteins (E₁, E₂, and C) was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in a discontinuous buffer system and the order of affinity was found to be C> E₁> E₂. Specific conditions for binding of TA to each of the virus proteins were investigated.

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DNA prepared from cell lines and transplanted tumors originating from five representative types of BKV-induced hamster tumors was examined for the presence of the BKV genome by analyzing DNA/DNA reassociation kinetics. BKV DNA sequences were detected in all cases. There were only a few (1-4) copies of BKV DNA per cell in one osteosarcoma and two ventricular tumors (one choroid plexus papilloma and one ependymoma), but there were multiple (up to 150) copies in one osteosarcoma, one ventricular tumor (choroid plexus papilloma), two insulinomas, one pineocytoma, and one cerebral neuroblastoma. In some cases the number of copies of the viral DNA differed among sister cell clones derived from the same primary tumor. Apparently some tumors contained nonintegrated free viral DNA besides the integrated BKV genome.

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The purpose of these studies was to determine the proportion of each immunoglobulin class/subclass in blood and colostrum of the pig and sheep, which would bind to staphylococcal Protein A. The concentrations of porcine IgG, IgM, and IgA were determined for serum and colostral whey from five sows. Similar measurements were made on two fractions produced by elution of the sample through a Protein A-Sepharose column : fraction 1, immunoglobulins which did not bind to Protein A, and fraction 2, immunoglobulins which bound to Protein A. The concentrations of ovine IgG₁, IgG₂, IgM, and IgA were measured for serum and colostral whey from six ewes, and again similar measurements were made after elution of each ovine sample through Protein A-Sepharose.
All classes/subclasses of porcine and ovine serum and colostral immunoglobulins bound to Protein A to some extent. More than 90% of IgG from both porcine colostral whey and serum bound to Protein A. Ovine IgG₁ from most ewes possessed a low affinity for Protein A whereas ovine IgG₂ generally possessed a high affinity; 100% of the IgG₂ in ovine colostral whey samples bound to Protein A. There was remarkable variation between individuals in the binding capacity of porcine IgM and each of the ovine immunoglobulins. For the ovine samples, in particular there were distinct differences between Protein A binding capacity of serum and colostral immunoglobulins of the same class/subclass.

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Autoantibody-producing B cell lines were established from peripheral blood lymphocytes of patients with systemic lupus erythematosus. Peripheral blood lymphocytes obtained from five of seven patients were successfully transformed by Epstein-Barr virus. Two of four established B lymphoblastoid cell lines examined in this study produced anti-nuclear factor antibodies and one of them produced anti-single-stranded DNA and anti-double-stranded DNA antibodies. These results indicate that B cell clones committed to self antigens are transformed by Epstein-Barr virus and continue to produce autoantibodies. In order to establish a monoclonal auto-antibody-producing B cell line, the cells were cloned by a limiting dilution method. The data suggest that it is possible to establish a monoclonal autoantibody-producing B cell line by the combination of transformation of B cells by Epstein-Barr virus and extensive cloning.

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