The plasmids R401 and Rtsl belong to the same incompatibility group, IncT. The nucleotide sequence of the basic replicon of R401 consisting of 1, 857 base pairs was determined and compared with that of mini-Rtsl previously reported. The mini-R401 was found to be composed of two clusters of direct repeated sequences flanking a large open reading frame that could encode a 33, 000 Mr protein (RepA protein) consisting of 288 amino acids. This structure of mini-R401 is quite similar to that of mini-Rtsl. Furthermore, the nucleotide sequence of mini-R401 is identical to that of mini-Rtsl except for eleven nucleotides; three are located near the carboxyl terminus portion of the RepA coding region (repA) and four are in the repeated sequences (incI) located downstream from repA. Incompatibility study showed that mini-R401 plasmid coexisted stably with the cloned incI repeats of mini-Rtsl, suggesting that mini-R401 RepA protein binds to incI repeats of mini-Rtsl less efficiently than does mini-Rtsl RepA protein.

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The composition and the nature of the linkage of fatty acids and the Shwartzman activity of lipopolysaccharide (LPS) preparations derived from oral gram-negative bacteria including Bacteroides gingivalis, Bacteroides loesheii, Eikenella corrodens, Fusobacterium nucleatum, and Actinobacillus actinomycetemcomitans were examined. 3-Hydroxylated and nonhydroxy fatty acids of various chain lengths were found in all of the LPS preparations. All nonhydroxy fatty acids were found to be ester-bound, and part of the 3-hydroxy fatty acids in the LPS of B. gingivalis, E. corrodens, F. nucleatum, and A. actinomycetemcomitans were shown to be involved in ester linkage. It was also suggested that the hydroxy group of the ester-bound 3-hydroxy fatty acid of the LPS of F. nucleatum and A. actinomycetemcomitans is at least partly substituted by another fatty acid, but in the LPS of B. gingivalis and E. corrodens it is not. The main amide-linked fatty acid of the LPS of B. gingivalis, E. corrodens, F. nucleatum, and A. actinomycetemcomitans was 3-hydroxyheptadecanoic, 3-hydroxydodecanoic, 3-hydroxyhexadecanoic, and 3-hydroxytetradecanoic acid, respectively. The results of the Shwartzman assay showed that the E. corrodens LPS was the most active among the preparations tested, and that the Shwartzman toxicity of Bacteroides LPS is extremely low.

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Production of an extracellular enzyme complex (carrageenase) was studied by examining cell-free fluids from cultures of a marine Cytophaga, 1k-C783, growing on different media.
Among artificial sea water salts, only NaCl and MgCl₂ were utilized by the organism to produce carrageenase. The minimal concentrations of suitable com₂ binations of NaCl and MgCl₂ were found to be 0.05M NaCl plus 0.25M MgCl₂, and 0.15M NaCl plus 0.15M MgCl₂. KCl and CaCl₂ did not have any role in carrageenase production in ZoBell 2216 E broth medium.
Carrageenase was synthesized continuously within the resting cells and was released from the cells as well as in the growing cells, when nutrient had been supplied.

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For detection of Legionella pneumophila and determination of its serogroup, the modified staphylococcal coagglutination test was studied in detail. Crossreactions in serum-agglutination tests were observed among serogroups, but immuno-globulin-coated staphylococcal cells could detect L. pneumophila with high sensitivity (a cell concentration with an absorbance of 0.008 at 660nm could be detected) and serogroups could be determined without cross-reactions. Moreover the coexistence of other bacteria did not affect the results of the test. These results suggest that the staphylococcal coagglutination test is useful for detection and identification of Legionella, especially in environmental samples, and for serogrouping of isolates of L. pneumophila from clinical specimens.

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Vaccinia viruses LC16m0 and LC16m8 are temperature-sensitive and low-neurovirulent variants derived from the Lister (Elstree) (LO) strain. Analyses of genome DNAs by digestion with restriction endonucleases and cross-hybridization of the digested fragments revealed that LC16m0 and LC16m8 possess a new XhoI site in addition to the 14 XhoI sites of LO. This new site is located at about 12×10⁶ daltons from the right terminal end. There was no significant difference in the genome structures between the LC16 variants and LO except the new XhoI site and their terminal fragments which were not identified in LO owing to their heterogeneity. With HindIII digested fragments, there was no difference among the three viruses. This complete mapping raised the possibility that the putative gene responsible for temperature sensitivity and neurovirulence is located at the region of the XhoI site found in LC16m0 and LC16m8.

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Five strains of male and female mice were infected with salivary gland-passaged murine cytomegalovirus (SG-MCMV) intraperitoneally. Although none of them became hyperglycemic, 13-30% of BALB/c male and female, ICR/Slc male and female and C57BL/6J male mice had abnormal values in glucose tolerance tests (GTT) 14 to 30 day post infection. Serum insulin levels in BALB/c male mice were low and infective virus was detected in the pancreas during the acute phase of infection. Histopathology showed mild edematous changes with inflammatory cell infiltrations in the pancreas. Viral antigen was located in acinar cells and occasionally in beta cells by an immunofluorescence test.

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Murine B cell mitogens such as bacterial lipopolysaccharide (LPS), butanol-extracted water soluble adjuvant (Bu-WSA), dextran sulfate (DS), synthetic muramyl dipeptide (MDP), and its analog MDP-Lys (L18) do not show any mitogenic ability in vitro on human peripheral blood lymphocytes or mixed cell populations of purified T and B cells obtained from the lymphocytes in an ordinary culture system. However, these mitogens are capable of enhancing the mitogenic effect of concanavalin A (Con A) in the cultures.
In the presence of one of these mitogens, the activity of interleukin 2 (IL 2), but not interleukin 1, in the supernatants obtained from cultures containing Con A-stimulated T cell and B cell populations was higher than that of control cultures. The role of the newly produced IL 2 in the synergistic effect of the mitogens in human lymphocyte cell cultures was discussed.

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Biosynthetic processing of the T-cell surface receptor for interleukin-2 was investigated in a cultured human T-cell line MT-1 by means of metabolic and cell surface radiolabeling followed by immunoprecipitation with a monoclonal anti-receptor antibody (anti-Tac) and analysis by one- and two-dimensional polyacrylamide gel electrophoresis.
The nascent precursor of the receptor (M_r=about 40, 000, pI=6.2-6.5) underwent a post-translational modification giving rise to the mature receptor (IL-2R; M_r=60, 000-65, 000, pI=4.2-4.7) within 2-4hr. The post-translational processing of IL-2R caused a 20, 000-25, 000 increase in apparent molecular weight and a 2.0-2.5 acidic shift in the isoelectric point. The increase in molecular weight was attributable mainly to addition of sugar residues including glucosamine and galactose, and the charge shift to the addition of sialic acids. A carboxylic ionophore monensin completely blocked the maturation of IL-2R at the mid-stage of the processing. Fatty acid attachment appeared to comprise one of the steps of the post-translational modification.
Two-dimensional analyses of IL-2R biosynthesis enabled identification of the precursor of IL-2R and its intermediate forms, from which it was partially possible to estimate reactions involved in the maturation of the precursor molecule.

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