Human cmbryo lung cells infected with rhinovirus type 2 (HGP strain) were sampled at intervals during viral growth and thin sections examined by electron microscopy. Infectivity assay showed an increase of intracellular virus 7 to 8 hr postinoculation and a peak titer at 16 to 18 hr. Changes resulting from infection, as revealed by electron microscopy, comprised (i) the appearance in the cytoplasm, at 8 hr postinfection, of large ribosomal clusters, membrane-enclosed bodies which proliferated extensively in the central zone of the cell, and viroplasm, aggregates of irregularly dense, coarse, granular material, and (ii) the appearance in the cytoplasm, at 16 hr postinoculation, of recognizable progeny virus particles. The particles were aligned along parallel fibrils or were found singly in some instances. As incubation continued, the particles became increasingly more spherical, and formed parallel long rows, and (iii) eventually, 24 hr after inoculation, formed closely packed viral crystals of a rectangular or hexagonal lattice. The mature progeny particles were 26 to 28mμ diameter. These changes were reminiscent of those reported previously for the polio and other enteroviruses.

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Induction of chloramphenicol (CM) resistance in Staphylococcus aureus was investi-gated using 166CM derivatives and analogues. It was found that 18 compounds of the samples used were able to induce resistance to CM in Staphylococcus aureus S1477 harboring an inducible CM-resistance determinant. Most of the samples which had a nitrophenyl moiety and a D-or DL-threo isomer in its steric configuration were found to have inducer activity for CM resistance. Competent inducers are D-isomer CM derivatives which have another substituent in place of the hydroxyl group at carbon atom 3 in the propanediol of the drug.

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Comparison was made among Mycobacterium nonchromogenicum, M. terrae, M. novum and subgroup "V" (M. triviale). These organisms together are differentiated from other mycobacteria of group II and group III by the following characters: (1) Sensitiveness to ethambutol; (2) Tolerance to nitrite; (3) Tolerance to Tween 80; (4) In-ability to utilize glucose and succinate in the presence of glutamate. To exclude the influence of growth rate, rough colony mutants (R-type mutants) were isolated from M. nonchromogenicum, M. terrae and M. novum and compared with each other and subgroup "V" that was originally of R-type. The R-type mutants of M. nonchromogenicum were similar to those of M. terrae, with the exception of the intensity of nicotinamidase and pyrazinamidase activities. These two have been suggested to belong to the same taxon, appropriate name of which is M. nonchromogenicum. The R-type mutants of M. novum were similar to the subgroup "V", with the exception of the intensity of arylsulfatase activity. It has been considered that subgroup "V" is an R-type mutant of M. novum. Although M. nonchromogenicum and M. novum could be differentiated from each other by the intensity of the arylsulfatase, nicotinamidase and pyrazinamidase activities and requirement of nitrogen compounds, these two organisms are differentiated from other mycobacteria by the same characteristics and are therefore considered to be closely related organisms.

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Two kinds of polysaccharides, glucan and glycopeptide (galactomannan-peptide), were obtained from Aspergillus fumigatus (IFO 5840) by extraction with 50% pyridine and were purified by fractional precipitation with acetone, by a column chromatography on Dowex-50 and DEAE-cellulose and by the gel filtration on Sephadex G-50 and G-200. The glycopeptide, designated APSK-66 fraction, showed both an Arthus and delayed type (tuberculin type) skin reactions in sensitized rabbits and guinea pigs. By treatment with proteolytic enzymes, the delayed type skin reactivity of APSK-66 fraction was reduced but the Arthus type skin reactivity was not affected. However, the Arthus type skin reactivity of APSK-66 fraction was completely lost by periodate oxidation, and the delayed type skin reactivity of APSK-66 fraction was retained. The APSK-66 fraction showed precipitation, complement fixation and passive hemagglutination reactions with rabbit antisera against A. fumigatus. Glucan, designated as APSK-33 fraction, did not show any immunological activity when tested in the present experiment. The chemical structures of the glucan and galactomannan were discussed.

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We attempted to purify the K-agglutinogen of Bordetella pertussis by mild procedures. From the supernatant of sonic treated cells, the K-agglutinogen was separated by a successive use of O-diethylaminoethyl (DEAE)-cellulose column chromatography, ammonium sulfate precipitation and O-carboxymethyl (CM)-cellulose column chromatography. The specific activity of purified K-agglutinogen increased 64-128 fold without damaging either the L or S antigens, and recovery was about 86%. A fraction containing mainly S-agglutinogen, was also obtained. The K-agglutinogen, which was a simple protein with an S value of 2.5, was confirmed to be in a highly purified state by a gel-diffusion test, K-antibody production and physicochemical tests, and was also found to be free from other biologically active substances of B. pertussis: namely heat labile toxin, hemagglutinin, histamine-sensitizing factor and O-antigen. No protective activity was found in the purified K-agglutinogen or against intracerebral challenge with B. pertussis in mice.

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Electron microscopic examination of chinese cabbage leaves systemically infected with turnip yellow mosaic virus (TYMV) showed that numerous particles assumed to be virus were present in the cytoplasmic spaces between clumped chloroplasts. In the general ground cytoplasm TYMV particles were undistinguishable from the ribosomes. When whole leaves, detached from intact plants showing mosaic, were heated at 60C for 5min and kept at room temperature (about 20C) for 18hr, particles located in the spaces between chloroplasts and general cytoplasm were apparently crystallized. No such crystalline arrays were seen in healthy cells. The interparticle distance in the crystals formed in wilted tissue was 270-300A. There was no evidence that cytoplasmic ribosomes have a tendency to crystallize under such conditions. It is suggested that TYMV particles are crystallized by the wilting procedure used.

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The studies were conducted on the inactivation of aminoglycosidic antibiotics including a new antibiotic, lividomycin, by a cell-free fraction from a strain of Pseudomonas aeruginosa isolated from the urine of a patient with cystitis. The strain strongly inactivated No. 2230-C (mannosyl paromomycin), paromomycin, kanamycin, aminodeoxykanamycin and neomycin but did not inactivate lividomycin A, dihydrostreptomycin and gentamicin. Inactivated-No. 2230-C, -paromomycin and -kanamycin were isolated and purified using column chromatography techniques. Inactivated antibiotics were found to be reactivated by the treatment with alkaline phosphatase. According to the reactivation by alkaline phosphatase and analytical data, it was concluded that the inactivated products were monophosphorylated derivatives of each antibiotic.

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