bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of concatemeric plasmids of Neisseria gonorrhoeae
Authors: Johnson S R , Anderson B E , Biddle J W , Perkins G H , DeWitt W E
Published: January 2020

Three strains of Neisseria gonorrhoeae carried novel plasmids of 7.8 megadaltons (mdal) molecular mass in addition to plasmids previously observed in this organism. The presence of the 7.8-mdal plasmids was not accompanied by any distinguishable phenotype in the strain possessing them. Analysis of plasmid DNA with restriction endonucleases showed that these plasmids were composed of three directly repeated copies of a 2.6-mdal cryptic plasmid frequently found in N. gonorrhoeae. In addition, the 7.8-mdal plasmids exhibited characteristics common to the 2.6-mdal plasmid, structural lability and sites resistant to cleavage with HpaII. The concatemeric forms of the cryptic plasmid appear to be stable in these strains and do not undergo internal recombination to produce the 2.6-mdal monomer, nor were higher concatemers detected.
Vibrio factors cause rapid fluid accumulation in suckling mice
Authors: Nishibuchi M , Seidler R J , Rollins D M , Joseph S W
Published: January 2020

Non-O-1 and O-1 Vibrio cholerae and Vibrio fluvialis isolated from clinical and environmental sources were examined for virulence factor production in 3-day-old suckling mice and in Y-1 tissue culture. The responses of the suckling mice to intragastrically administered bacterial cultures were measured by intestinal fluid accumulation (FA), diarrhea, and mortality. Regardless of the O-serovar, source of isolation, or ability to produce cholera toxin, all strains of V. cholerae stimulated increased FA, which was measurable in the mice at 4 h post-inoculation. The factor(s) causing these symptoms was found to be distinct from cholera toxin by the kinetics of FA and serological difference from cholera toxin based on in vivo neutralization tests. In most instances, FA was followed by high rates of mortality. Y-1 mouse adrenal tumor cell assays also showed that many V. cholerae produced extracellular heat-labile cytotoxic factor(s), and many cholera toxin-negative strains also caused a cytotonic-like morphological response. The majority of V. fluvialis strains produced smaller amounts of cytotoxic factor(s) but no cytotoxic reactions. The factor which stimulates rapid FA in suckling mice could be one of several virulence-associated factors contributing to diarrheal disease by nontoxigenic vibrios, but this is not verified at present.
Common antigens of streptococcal and nonstreptococcal oral bacteria: characterization of wall-associated protein and comparison with extracellular protein antigen
Authors: Schöller M , Klein J P , Sommer P , Frank R
Published: January 2020

A soluble wall-associated common protein (WAP) has been isolated from cell wall-extracted antigens of exponentially growing cells of Streptococcus sanguis OMZ9, two serotypes (a and e), of Streptococcus mutans and Actinomyces viscosus OMZ104. The WAP antigens from the different strains were obtained by chromatography on an anti-rabbit immunoglobulin column of sodium dodecyl sulfate-dissociated immunoprecipitates. The affinity-isolated WAP antigens from the different oral bacteria were identical, as demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (showing an apparent molecular weight of 80,000) and amino acid and sugar compositions. This WAP antigen, common to all bacterial strains tested, consisted of 90% protein and 10% sugar. A comparison of the chemical properties of this WAP antigen and of the soluble extracellular common protein antigen showed that, although having similar amino acid and sugar compositions, the two proteins are different. Electron micrographs developed after immunocytological labeling of the WAP antigen on whole cells confirmed that it is located on the cell wall.
Cytoplasmic distinction of avirulent and virulent Rickettsia prowazekii: fusion of infected fibroblasts with macrophage-like cells
Authors: Winkler H H , Daugherty R M
Published: January 2020

L-929 cells with virulent or avirulent Rickettsia prowazekii growing in their cytoplasm were fused with cells of the macrophage-like cell line RAW264.7. Fusion occurred between the two cell types, producing heterokaryons containing R. prowazekii. Both the number of rickettsiae per infected heterokaryon and the percentage of heterokaryons infected with rickettsiae decreased in experiments with the avirulent strain compared to those with the virulent strain. These results indicate that the differential survival of the virulent strain in macrophages is some unknown function of the cytoplasm of the macrophage and that the distinction is not only at the phagolysosome level.
Effect of erythrocyte ingestion on macrophage antibacterial function
Authors: Hand W L , King-Thompson N L
Published: January 2020

Individuals with sickle cell anemia are subject to serious infections caused by a number of bacteria, including Salmonella species and Staphylococcus aureus. It has been suggested that in sickle cell anemia, extensive erythrophagocytosis by macrophages may interfere with their antibacterial function and thereby predispose to infection. As a means of investigating this possibility, we evaluated the effects of erythrocyte ingestion on the Killing of Salmonella typhimurium by peritoneal macrophages and of S. aureus by alveolar macrophages. Monolayers of rabbit macrophages were exposed to erythrocytes or latex particles immediately before and during bacterial challenge. Erythrophagocytosis markedly inhibited intracellular killing of S. typhimurium by peritoneal macrophages (bacterial survival was 181% of control) and of staphylococci by alveolar macrophages (bacterial survival was greater than 200% of control). Exposure to latex particles depressed the bactericidal activity of alveolar macrophages to a lesser degree. Next we investigated the possibility that erythrophagocytosis inhibits oxidative bactericidal mechanisms in macrophages. Hexose monophosphate shunt activity was stimulated by erythrocyte ingestion. However, zymosan-induced superoxide generation and chemiluminescence were suppressed by erythrocytes. Furthermore, a cell-free (hypoxanthine-xanthine oxidase) system for chemiluminescence generation was also depressed in the presence of erythrocytes (intact or lysate) or by purified hemoglobin. These studies reveal that erythrophagocytosis inhibits macrophage antibacterial function, probably because of interactions between erythrocyte components and reactive products of phagocyte oxygen metabolism. This host defense abnormality may predispose to bacterial infection in certain hemolytic anemias.
Identification and preliminary characterization of a major heat-stable surface antigen of Actinomyces israelii by two-dimensional (crossed) immunoelectrophoresis
Authors: Ayakawa G Y , Williams B L , Kenny G E
Published: January 2020

We have identified, employing two-dimensional (crossed) immunoelectrophoresis, a major heat-stable surface antigen in Actinomyces israelii with an electrophoretic mobility of 0.86 compared to bovine albumin. The surface component was protease sensitive and non-dialyzable and was found in relatively large amounts in two serotype 2 strains of A. israelii (WVU 307 and ATCC 23860). Serotype 1 strains either lacked antigen 0.86 (ATCC 12103 and CDC X522) or contained small quantities of a cross-reacting antigen which was not identical to antigen 0.86 (CDC W855). Thus, antigen 0.86 may be useful in the serotaxonomy of A. israelii. Our data also suggest the possibility that a greater degree of antigenic heterogeneity exists within the species than can be accommodated within the two currently recognized serotypes.
Pharmacological modulation of suppressor cell activity in mice with disseminated histoplasmosis
Authors: Deepe G S , Kravitz G R , Bullock W E
Published: January 2020

Indomethacin and cyclophosphamide (CY) were used in an attempt to modify the suppressive effects of spleen cell populations from mice with disseminated histoplasmosis at 1 week of infection. In vitro addition of indomethacin did not alter the depressed plaque-forming cell response to sheep erythrocytes of normal spleen cells cocultured with unfractionated or nylon wool-fractionated spleen cells from infected mice. Likewise, indomethacin given intraperitoneally did not enhance the subnormal in vivo plaque-forming cell response of spleen cells from infected mice. Conversely, 20 mg of CY per kg given intraperitoneally 2 days before or 6 h after the inoculation with Histoplasma capsulatum partially reversed the suppression effected by splenic T cells (nylon wool passed) in vitro, whereas 50 mg of CY per kg given intraperitoneally 6 h after the injection of H. capsulatum ablated suppressor T cell activity in vitro; neither dosage of CY altered the suppression mediated by unseparated or nylon wool-adherent spleen cells. Furthermore, the administration of 50 mg of CY per kg failed to improve the depressed footpad responses of mice infected for 1 week to sheep erythrocytes in sheep erythrocyte-sensitized mice or to histoplasmin. These findings indicate that in experimental disseminated histoplasmosis, suppression effected by splenic T cells can be alleviated by CY; however, there is a persistent immunosuppressor mechanism(s) that cannot be counteracted by either indomethacin or CY.
Cytopathic effect of whole cells and purified membranes of Mycoplasma hyopneumoniae
Authors: Geary S J , Walczak E M
Published: January 2020

Marked cytopathic effect was produced in both porcine lung fibroblasts and MRC-5 human lung fibroblasts with doses of 7.5 X 10(6) and 1.5 X 10(7) CFU of Mycoplasma hyopneumoniae J per ml, respectively. M. hyopneumoniae VPP11, at a concentration as low as 1.25 X 10(7) CFU/ml, was capable of causing cytopathic effect in MRC-5 monolayers also. The infected monolayers developed patches of detached or lysed cells within 48 h. At a protein concentration of 2 micrograms/ml, M. hyopneumoniae membranes, prepared from freeze-thaw lysed cells, were capable of inducing cytopathic effect in MRC-5 fibroblasts within 24 h. The cytoplasm did not contain any cytotoxic activity. This indicates that the cytopathic factor is located in the cell membrane. This factor appears to be protein in nature. It was heat labile (100 degrees C, 15 min) and was destroyed by pronase (1 mg of pronase per 1 mg of membrane protein). It appears to be antigenic, since rabbit anti-M. hyopneumoniae serum was capable of neutralizing its cytopathic activity.
Selenium and immune functions in humans
Authors: Arvilommi H , Poikonen K , Jokinen I , Muukkonen O , Räsänen L , Foreman J , Huttunen J K
Published: January 2020

Earlier animal experiments have shown that selenium depletion may decrease immune functions. In this human study, 40 volunteers from a population with low serum selenium concentrations were supplemented with selenium or placebo for 11 weeks. Blood samples were drawn at intervals for analysis of selenium status and immune function. At the end of the supplementation period, plasma selenium levels were 74 ng/ml in the placebo group and 169 ng/ml in the supplemented group. The improvement in selenium status was associated with a 57% increase in the activity of platelet glutathione peroxidase in the group supplemented with selenium, but there was no increase in the activity of this enzyme in the placebo-treated subjects. Immune function was measured in vitro by tests of lymphocyte and granulocyte activity. Intracellular killing of Staphylococcus aureus by granulocytes was slightly lower in the placebo group than in the selenium group at the end of the supplementation period (77.2 compared to 85.2%; P less than 0.05). No significant changes were observed in phagocytosis, chemotactic factor generation, antibody or leukocyte migration inhibitory factor production by lymphocytes, or proliferative responses to phytohemagglutinin or concanavalin A. These results suggest that the selenium deficiency of the order found in Finland and some other areas of the world has little, if any, influence on the immune functions measured in this study.
Purification of Vibrio cholerae soluble hemagglutinin and development of enzyme-linked immunosorbent assays for antigen and antibody quantitations
Authors: Svennerholm A M , Strömberg G J , Holmgren J
Published: January 2020

Soluble hemagglutinin (HA) from an El Tor Vibrio cholerae strain (serotype Ogawa) was purified by means of a sequence of salt precipitation, gel filtration, and agarose electrophoresis. The purified material, which gave a single precipitation line in immunodiffusion tests with homologous antiserum, showed immunological identity reactions in double diffusion-in-gel with soluble HA produced by various classical and El Tor strains of different serotypes. Purified HA was used for development of an enzyme-linked immunosorbent assay for titration of specific antibodies against soluble HA and for quantitation of this antigen. Rabbit anti-HA serum reacted in high titer with the soluble HA coated on polystyrene microtiter plates, whereas antiserum against cholera toxin, lipopolysaccharide, or whole washed V. cholerae showed little or no reactivity. In inhibition tests as little as 2.5 ng of soluble HA could be detected with the enzyme-linked immunosorbent assay. Culture supernatants of different El Tor as well as classical V. cholerae strains all completely inhibited the binding of anti-HA antibody to solid-phase-bound homologous antigen, but the amounts of HA produced by individual strains varied at least 1,000-fold. Only 2 of 10 paired acute- and convalescent-phase sera from Bangladeshi cholera patients showed significant titer increases against soluble HA in parallel titrations.
Utilization of fructose and ribose in lipopolysaccharide synthesis by Veillonella parvula
Authors: Tortorello M L , Delwiche E A
Published: January 2020

Veillonella parvula, which cannot ferment or incorporate most sugars, incorporated radioactivity from [14C]ribose and [14C]fructose into cellular lipopolysaccharide (LPS) in the presence of lactate as an energy source. It was shown that virtually all of the fructose carbon which was assimilated into LPS material appeared in hydrophilic LPS components, and almost none was assimilated into fatty acid LPS components. The assimilation of lactate carbon into LPS in the presence of fructose was shifted from the hydrophilic toward the fatty acid components.
Pathogenesis of K papovavirus infection in athymic nude mice
Authors: Mokhtarian F , Shah K V
Published: January 2020

The fatal outcome of K virus infection in infant mice and cytoxan-treated adult mice is related to their inability to mount a prompt antibody response to the virus. Athymic nude mice infected with K virus exhibited no clinical illness and no detectable virus-specific immunoglobulin G (IgG) response, but they did exhibit a low level of virus-specific immunoglobulin M response. Transfer of spleen cells from K virus-primed nude mice to infected infant mice conferred complete protection against K virus-induced mortality. This protection was diminished by the depletion of B cells but not by the depletion of adherent cells from the primed spleen cells. B cell response is therefore important in the recovery of nude mice from K virus infection.
Tunicamycin treatment inhibits the antiviral activity of interferon in mice
Authors: Maheshwari R K , Husain M M , Attallah A M , Friedman R M
Published: January 2020

Earlier we reported that tunicamycin (TM) treatment of L cells in vitro significantly enhances the antiviral activity of interferon (IFN) against viruses (such as vesicular stomatitis, Sindbis, and herpes simplex) which bud from membranes. However, no such enhancement of the antiviral activity of IFN by TM was observed against encephalomyocarditis virus (EMCV) (nonbudding). We were interested to know whether TM would similarly enhance the antiviral activity of IFN and IFN inducers in vivo against Semliki Forest virus (SFV) and EMCV infections in mice. It was observed that TM alone (0.001 to 5.0 micrograms per mouse) did not protect mice against infections of SFV and EMCV; instead, TM-treated mice died with virus-specific paralytic symptoms earlier than untreated animals. The enhanced mortality in TM-treated and SFV- or EMCV-infected mice was associated with the concomitant increase in virus titer in brain tissue. IFN significantly protected mice against SFV and EMCV infections. The antiviral protection of mice by IFN against both the viruses was markedly inhibited by TM administration. IFN inducers (polyinosinic acid-polycytidylic acid, 6-MFA [a mixture of proteins, polysaccharides, and double-stranded DNA isolated from Aspergillus ochraceus ATCC 28706]) protected a significant number of mice against SFV infection. However, no such protection was observed in mice injected with a combination of TM and IFN inducer. These results indicate that TM treatment inhibits the antiviral action of IFN or IFN inducers in vivo.
Protection against experimental Bordetella bronchiseptica infection in mice by active immunization with killed vaccine
Authors: Sekiya K , Kawahira M , Nakase Y
Published: January 2020

Mice immunized with a killed vaccine of phase I Bordetella bronchiseptica were challenged with various numbers of virulent B. bronchiseptica by intraperitoneal, intracerebral, or intranasal routes. The course of infection was compared among these routes, and the protective effect of vaccination was quantitatively analyzed. In ddN mice infected intraperitoneally with 1.8 X 10(8) cells (ca. 80 times the 50% lethal dose [LD50]) the organisms rapidly increased in the intraperitoneal fluid, spleen, and liver within few days and caused splenic atrophy, septicemia, and death. However, immunizations with 5 X 10(9) cells gave the mice a high agglutinin titer and suppressed the increase in the number of organisms. With four immunizations, the lungs and livers were clear within 3 days, and with one or two immunizations, they were clear within 7 days. These immunizations effectively protected the mice from death but did not protect them from splenic atrophy. In the intracerebral infection with 1.4 X 10(6) cells (ca. 1.2 X 10(5) LD50), the number of organisms rapidly increased in the brain and caused encephalitis, splenic atrophy, and death. However, four or five immunizations completely suppressed the increase in the brain and protected the mice from death and splenic atrophy. After intranasal infection with 4 X 10(6) cells (ca. 25 LD50), the organisms rapidly increased in the nasal cavity and lungs and caused pneumonia and death. Immunization with 5 X 10(9) cells was effective in clearing the organisms from the lungs and in protecting against death and splenic atrophy. However, the organisms were not cleared from the nasal cavity for 60 to 150 days after the challenge with as little as 10(2) cells, even in the mice with an agglutinin titer as high as 1:10,000.
Relationship of interferon-inducing particle phenotype to encephalomyocarditis virus-induced diabetes mellitus
Authors: Cohen S H , Bolton V , Jordan G W
Published: January 2020

The B (nondiabetogenic) and D (diabetogenic) variants of encephalomyocarditis (EMC) virus were studied to further define the role of the interferon (IFN) system in murine virus-induced diabetes mellitus. The relationship between the initial multiplicity of infection with EMC-B and the IFN yield showed that cells infected with one IFN-inducing particle produce a maximum amount of IFN, whereas IFN production is suppressed in cells infected with two or more particles. The IFN yield induced by EMC-D was less than 5% of that induced by EMC-B, allowing the designation of the B and D variants as Ifp+ and Ifp-, respectively. The Ifp+ property of the virion was shown to be responsible for the greater sensitivity of EMC-B to exogenous IFN as a result of primed local IFN induction. The data indicate that different Ifp phenotypes occur in nature and are associated with the development of diabetes in mice.
Molecular basis of immunological cross-reactivity between Treponema pallidum and Treponema pertenue
Authors: Baker-Zander S A , Lukehart S A
Published: January 2020

Protein antigens of Treponema pallidum, Nichols strain, and Treponema pertenue, Gauthier strain, were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting techniques. Treponemal proteins were solubilized in 1% sodium dodecyl sulfate, electrophoresed on 12.5% polyacrylamide gels, and either stained with Coomassie brilliant blue or electrophoretically transferred to nitrocellulose paper. These antigen blots were incubated with sera from rabbits infected with either T. pallidum or T. pertenue and 125I-labeled staphylococcal protein A and exposed to X-ray film for visualization of antigenic molecules. Protein profiles of each organism separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and stained with Coomassie brilliant blue showed no distinguishable differences. Antigenic profiles as determined by Western blots were similar with two exceptions. A 39,500-dalton band was present on T. pertenue but absent from T. pallidum, and a 19,000-dalton band was present on T. pallidum but absent from T. pertenue (although two additional antigenic bands at 21,000 and 18,000 daltons were seen on T. pertenue). Because these differences were detected by using antisera raised against either T. pallidum or T. pertenue, these molecules must contain some antigenic determinants in common despite their differences in molecular weight.
Extracellular dextranase activity produced by human oral strains of the genus Bifidobacterium
Authors: Kaster A G , Brown L R
Published: January 2020

Three strains of anaerobic, dextranase-producing, gram-positive, rod-shaped bacteria were isolated from human dental plaque associated with root carious lesions. The isolates produced a molar ratio of acetate to lactate from glucose fermentation ranging from 1.1 to 1.9. Each strain also produced fructose-6-phosphate phosphoketolase. The isolates were identified as belonging to the genus Bifidobacterium, but from their carbohydrate fermentation patterns they did not appear to be strains of Bifidobacterium dentium. These microorganisms fermented high-molecular-weight dextrans. A partial characterization of the dextranase activity was included in this study and revealed an extracellular dextranase with a pH optimum of 7.1. Analysis of the dextran degradation products demonstrated the liberation of saccharides larger than 1 glucose unit. It was concluded that this enzyme used an endohydrolytic mode of dextran cleavage.
Differential complement activation and susceptibility to human serum bactericidal action by Vibrio species
Authors: Tamplin M L , Specter S , Rodrick G E , Friedman H
Published: January 2020

The ability of Vibrio vulnificus to resist human serum bactericidal action and to activate human complement was compared with similar cultures of Vibrio cholerae and Vibrio parahaemolyticus. Both V. vulnificus and V. parahaemolyticus had similar survival rates in sera and were much more resistant to killing than was V. cholerae. In contrast, V. vulnificus activated significantly less serum complement than did V. cholerae and V. parahaemolyticus. The relative ability of V. vulnificus to survive in serum and activate less complement than other Vibrio spp. tested may be related to its ability to cause chronic tissue infections and septicemias.
Monocyte-derived soluble suppressor factor(s) in patients with lepromatous leprosy
Authors: Sathish M , Bhutani L K , Sharma A K , Nath I
Published: January 2020

Peripheral blood monocytes from polar lepromatous leprosy (LL) patients were unable to support Mycobacterium leprae-induced in vitro lymphoproliferation of HLA-D-matched T cells from tuberculoid leprosy subjects, whereas those from responder individuals were able to do so. Monocyte-rich adherent cells from untreated LL patients released de novo soluble factors which inhibited antigen-induced lymphoproliferation to a greater extent and mitogenic responses to a lesser extent. Suppressive activity varied in different LL patients. However, the degree of suppression was similar in soluble factors obtained de novo and after treatment of adherent cells with heat-killed and freshly extracted, cryopreserved M. leprae. Treated patients showed less inhibition with de novo released soluble factors (27 +/- 7.7%) as compared to parallel soluble factors obtained after antigen treatment (44 +/- 4.8%) or with de novo soluble factors from untreated LL patients (62 +/- 14.2%). Similar supernatants from tuberculoid individuals showed no or insignificant effects on antigen-induced lymphoproliferation. The suppressive activity of LL soluble factors was produced for up to 72 h, was heat stable at 56 degrees C for 30 min, was indomethacin resistant, and resided in the greater than 25,000 molecular weight fraction.
Mapping of chromosomal genes that determine the El Tor biotype in Vibrio cholerae
Authors: Green B A , Newland J W , Holmes R K
Published: January 2020

The El Tor biotype of Vibrio cholerae has several characteristics that differentiate it from the classical biotype of V. cholerae. Among these are production of soluble hemolysin(s), a cell-associated hemagglutinin for chicken erythrocytes, resistance to polymyxin B, and resistance to bacteriophages of Mukerjee group IV. In the present study, we located the determinants for hemolysin (hly), chicken erythrocyte hemagglutinin (cha), and polymyxin B resistance (pmx) on the genetic map of V. cholerae. Transposon-facilitated recombination was used to perform conjugal matings between El Tor donor strains and classical recipient strains of V. cholerae. Recombinants were selected that had inherited specific nutritional markers from the donor strains and streptomycin resistance from the recipient strains. The recombinants were tested for the presence or absence of the unselected donor markers hly, cha, and pmx. These three El Tor biotype markers were found to be closely linked to each other and were located between the pyrA-201 and his-2 loci on the genetic map of V. cholerae.
Attachment and internalization of a Chlamydia trachomatis lymphogranuloma venereum strain by McCoy cells: kinetics of infectivity and effect of lectins and carbohydrates
Authors: Söderlund G , Kihlström E
Published: January 2020

The kinetics of attachment and ingestion of Chlamydia trachomatis serotype L1 by monolayers of McCoy cells were studied by using a method that discriminated between attachment and uptake. When about 1% of the McCoy cells was infected, the proteinase K-resistant chlamydial fraction, regarded as ingested chlamydiae, reached a constant value after about 3 h of incubation at 37 degrees C. Uptake of chlamydiae at 4 degrees C could not be demonstrated. The attached and ingested chlamydial fractions were constant over an eightfold increase in chlamydial inoculum. Chitobiose and chitotriose, the di- and trisaccharides of N-acetyl-D-glucosamine, reduced the association of C. trachomatis serotype L1 with McCoy cells. Higher concentrations of chitobiose also selectively inhibited ingestion of chlamydiae. A corresponding effect of chitobiose was also observed on the number of chlamydial inclusions. Wheat germ agglutinin, specific for N-acetyl-D-glucosamine residues, reduced the association of chlamydiae when incubated at 4 degrees C, but not at 37 degrees C. A small inhibiting effect of concanavalin A on association of chlamydiae, but no effect of the corresponding carbohydrates, indicates a nonspecific effect on chlamydial attachment of this lectin. These results suggest that beta 1 leads to 4-linked oligomers of N-acetyl-D-glucosamine are important in the specificity of attachment of C. trachomatis to McCoy cells.
Infectivity of organisms recovered from polymicrobial abscesses
Authors: Brook I , Walker R I
Published: January 2020

The ability to cause subcutaneous abscesses in mice was used to identify the pathogens among the bacteria recovered from 13 clinical abscesses. A total of 35 isolates (30 anaerobes and 5 aerobes), 16 of which were encapsulated, were recovered from these abscesses. Encapsulated organisms included eight Bacteroides spp. (three Bacteroides asaccharolyticus and one strain each of Bacteroides oralis, Bacteroides intermedius, Bacteroides biacutus, Bacteroides vulgatus, and Bacteroides ruminicola subsp. brevis), three anaerobic gram-positive cocci, two Clostridium spp., and two strains of Escherichia coli. Single organisms, or combinations thereof, obtained from these abscesses were inoculated subcutaneously into mice. All but one of the encapsulated organisms were able to cause abscesses by themselves and were recovered from the abscesses when inoculated with other organisms. Seven non-encapsulated organisms which were also recovered mixed with the encapsulated organisms were never able to cause abscesses nor could they be recovered after they were injected alone. Thirteen strains that did not induce abscesses when injected by themselves into mice survived when injected with other organisms which were encapsulated. In three instances, pairs of non-encapsulated organisms belonging to the last group were able to induce an abscess and survive in it when inoculated together. It was shown that the possession of a capsule by a clinical isolate increases the likelihood that it is a major contributor to the infectious process.
Vibrio cholerae expresses iron-regulated outer membrane proteins in vivo
Authors: Sciortino C V , Finkelstein R A
Published: January 2020

A comparison was made, using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, of the outer membrane proteins of four strains of Vibrio cholerae grown in vivo in infant rabbits and in vitro in low-iron and iron-supplemented defined media. In vivo-grown V. cholerae expressed novel outer membrane-associated proteins which, in part, were similar to those observed on V. cholerae grown in vitro under conditions of iron deprivation.
Immunoglobulin A proteases in gram-negative bacteria isolated from human urinary tract infections
Authors: Milazzo F H , Delisle G J
Published: January 2020

Several strains of gram-negative bacteria (seven genera, eight species) isolated from patients with urinary tract infections were found to hydrolyze myeloma immunoglobulin A (IgA) protein. Human IgG and IgM and colostrum IgA were not degraded by these organisms. Examination of cleavage digests showed two fragments of different electrophoretic mobilities, with antigenic reactivity and sodium dodecyl sulfate polyacrylamide gel electrophoresis profiles consistent with their identification as Fc and Fab components. The immunoelectrophoresis patterns of cleavage digests suggested that the proteases responsible for this hydrolysis may be dissimilar in the specificity of their IgA cleavage sites.
Biological activities of Eikenella corrodens outer membrane and lipopolysaccharide
Authors: Progulske A , Mishell R , Trummel C , Holt S C
Published: January 2020

Highly purified preparations of the outer membrane and lipopolysaccharide (LPS) of Eikenella corrodens strain ATCC 23834 and the outer membrane fraction (OMF) of strain 470 were tested in in vitro biological assays. The OMFs of both strains were found to be mitogenic for BDF and C3H/HeJ murine splenocytes. The E. corrodens LPS was mitogenic for BDF spleen cells; however, doses of LPS as high as 50 micrograms/ml failed to stimulate C3H/HeJ cells. When incubated with T-lymphocyte-depleted C3H/HeJ splenocytes, the strain 23834 OMF demonstrated significant mitogenic activity, indicating that the OMF is a B-cell mitogen by a mechanism other than that elicited by conventional LPS. The E. corrodens 23834 OMF and LPS were stimulators of bone resorption when tested in organ cultures of fetal rat long bones. In contrast, the strain 470 OMF was only weakly stimulatory. Both OMFs and LPSs demonstrated "endotoxic" activity, since as little as 0.062 micrograms of E. corrodens LPS and 0.015 micrograms of the OMFs induced gelation in the Limulus amebocyte clotting assay. Thus, despite having a "nonclassical" LPS biochemistry, the E. corrodens LPS elicits classical endotoxic activities. These results also indicate that the surface structures of E. corrodens have significant biological activities as measured in vitro. The expression of such activities in vivo may play an important role in the pathogenesis of periodontitis as well as other E. corrodens infections.
Piliated Bacteroides fragilis strains adhere to epithelial cells and are more sensitive to phagocytosis by human neutrophils than nonpiliated strains
Authors: Pruzzo C , Dainelli B , Ricchetti M
Published: January 2020

Fifteen unencapsulated B. fragilis strains isolated from human infections were examined for their capability to hemagglutinate erythrocytes of different species. Seven strains were found to hemagglutinate guinea pig and human (A,B,O) erythrocytes. This hemagglutination was resistant to treatment with D-mannose and several other sugars. Hemagglutinating strains were also capable of adhering to human epithelial cells and cultured human cell line (Intestine 407) and were 6- to 20-fold more adhesive than non-hemagglutinating strains. Pilus-like structures were found in negative-stained preparations on the hemagglutinating (and adhesive) strains but not on the others. Hemagglutinating and adhesive bacteria were 3- to 7-fold more sensitive to phagocytosis and 5- to 10-fold more sensitive to killing by human neutrophils than non-hemagglutinating ones.
I-E/I-C region-associated induction of murine gamma interferon by a haplotype-restricted polyclonal T-cell mitogen derived from Mycoplasma arthritidis
Authors: Cole B C , Thorpe R N
Published: January 2020

Cell-free supernatants from cultures of Mycoplasma arthritidis induced significant levels of interferon when cocultured with murine splenic cells. On the basis of physicochemical characteristics and antibody neutralization studies, the antiviral substance was identified as gamma interferon. Use of inbred and congenic mouse strains established that splenic cells from mice expressing the H2k and H2d haplotypes produced interferon in response to M. arthritidis culture supernatants, but those from mice with H2b and H2q haplotypes did not. Further studies with recombinant mouse strains established that interferon induction by the mycoplasma supernatant was associated with the haplotype expressed at the I-E/I-C subregion of the murine major histocompatibility complex. The specificity seen for interferon induction was identical with that reported earlier for induction of cytotoxic lymphocytes and for lymphocyte proliferation in response to the mitogen. All of these reactions appear to be dependent upon binding of the mitogen to specific I-E/I-C region-coded products present on splenic cell surfaces. The observations presented introduce the concept that microbial mitogens or their lymphokine products might modify immune responses and defense mechanisms of the naive host in a genetically restricted manner.
Hydroxyl Radical Scavengers Produce Similar Decreases in the Chemiluminescence Responses and Bactericidal Activities of Neutrophils
Authors: Repine John E. , Johansen Kirsten Staehr , Berger Elaine M.
Published: January 2020

The addition of hydroxyl radical (·OH) scavengers caused similar decreases in the chemiluminescence responses and killing of
Staphylococcus aureus
502A by human neutrophils in vitro.
Effect of type A Pasteurella multocida fractions on bovine polymorphonuclear leukocyte functions
Authors: Ryu H , Kaeberle M L , Roth J A , Griffith R W
Published: January 2020

The effect of various Pasteurella multocida fractions on bovine polymorphonuclear leukocyte (PMN) functions was examined in vitro by using two encapsulated strains, P-2383 and P-1062 (both are Carter capsular type A and of bovine origin). The ability of PMNs to ingest Staphylococcus aureus and iodinate protein was significantly inhibited in the presence of live cells, heat-killed whole cells, or saline-extracted capsules but not in the presence of the decapsulated heat-killed cells. None of the fractions of the two strains inhibited nitroblue tetrazolium reduction by PMNs. The saline extract did not inhibit the binding of iodine to protein by a reaction involving xanthine, xanthine oxidase, and horseradish peroxidase. The PMN inhibitory factor was further characterized as a heat-stable capsular material of greater than 300,000 molecular weight.
Evaluation in humans of attenuated Vibrio cholerae El Tor Ogawa strain Texas Star-SR as a live oral vaccine
Authors: Levine M M , Black R E , Clements M L , Lanata C , Sears S , Honda T , Young C R , Finkelstein R A
Published: January 2020

Texas Star-SR, an A- B+ mutant derived by nitrosoguanidine treatment from Vibrio cholerae El Tor Ogawa strain 3083, was fed to 68 volunteers as an oral vaccine in doses of 10(5) to 5 X 10(10) organisms with NaHCO3. Sixteen (24%) vaccinees experienced some loose stools (unrelated to vaccine dose), but in only one did the total stool volume exceed 1.0 liter. The vaccine strain was cultured from duodenal fluid of 35 of 46 (76%) persons who ingested doses of 10(8) organisms or greater. No A+ B+ toxinogenic revertants were found among 456 clinical isolates tested. Sixty-three vaccinees (93%) manifested seroconversions of vibriocidal antibody, whereas only 20 (29%) had significant rises in serum antitoxin titers. Paired intestinal fluids from 41 volunteers showed significant rises of secretory immunoglobulin A against lipopolysaccharide (29%), Ogawa outer membrane preparation (29%), and toxin (12%) antigens. In challenge studies with pathogenic V. cholerae El Tor Ogawa and El Tor Inaba, the attack rate in vaccinees (7 of 25) was significantly lower than in controls (18 of 25) (vaccine efficacy, 61%); furthermore, the diarrheal stool volume in vaccinees was significantly less than that in controls (P less than 0.01). Texas Star-SR served as a prototype to investigate the concept of immunoprophylaxis by means of attenuated strains as oral vaccines. These observations provide an invaluable background for planning future studies with newly developed attenuated strains prepared by recombinant DNA techniques.
Localization on encapsulated Cryptococcus neoformans of serum components opsonic for phagocytosis by macrophages and neutrophils
Authors: Kozel T R , Highison B , Stratton C J
Published: January 2020

Previous studies have shown that the cryptococcal capsule inhibits phagocytosis of Cryptococcus neoformans by macrophages and neutrophils. In this study, the binding sites of potential serum opsonins in immune and nonimmune sera were determined by immunoelectron microscopy, and the results were compared with the results of phagocytosis of the yeasts by mouse peritoneal macrophages and human neutrophils. Immunoglobulin G (IgG) from normal human serum showed low-density binding at the capsular surface and at sites throughout the capsule. Complement component C3 from normal serum bound heavily at the capsular surface. IgG from rabbit capsular antiserum showed relatively dense deposition at the capsular surface and at sites throughout the capsule. Cells opsonized with heat-inactivated human serum were engulfed poorly by both macrophages and neutrophils, indicating that the low-density deposition of IgG produced by normal serum was not adequate for opsonization. Yeasts opsonized with normal human serum were engulfed in large numbers by neutrophils and to a lesser extent by macrophages, indicating that neutrophils in particular were able to effectively utilize the opsonically active C3 which normal human serum deposited at the capsular surface. Yeasts opsonized with rabbit anticapsular serum were engulfed by both macrophages and neutrophils, indicating that the high density of surface IgG produced by capsular antiserum is an effective opsonin for both cells. These results suggest that the complement-neutrophil system is a possible defense mechanism in the nonimmune host.
Identification and preliminary characterization of saliva-interacting surface antigens of Streptococcus mutans by immunoblotting, ligand blotting, and immunoprecipitation
Authors: Ogier J A , Klein J P , Sommer P , Frank R M
Published: January 2020

The ability of surface protein antigens of Streptococcus mutans to interact with salivary components was examined by Western blot and immunoprecipitation methods. Immunoblotting of S. mutans OMZ175 wall-associated antigens revealed 10 major antigens, designated according to their estimated molecular weights. Four of them, with molecular weights of 135,000, 125,000, 120,000, and 115,000 in their denaturated form, bound salivary components. This property was further investigated by immunoprecipitation experiments: the reactivity with saliva was confirmed for antigens with molecular weights of 135,000, 125,000, and 120,000 in their native form, and their locations on the bacterial cell surface were established. These three antigens were characterized as glycoproteins; they directly bound concanavalin A, and pronase abolished their antigenicity, which was partly retained after treatment with NaIO4. Because of their distribution in several other stains of S. mutans, it will be of interest to study their possible implication in the mechanism of attachment of streptococcal strains to saliva-coated tooth surfaces.
Protection against fatal Klebsiella pneumoniae burn wound sepsis by passive transfer of anticapsular polysaccharide
Authors: Cryz S J , Fürer E , Germanier R
Published: January 2020

Klebsiella pneumoniae KP1-0 capsular polysaccharide (PS) was isolated from culture supernatants by coprecipitation with N-cetyl-N,N,N-trimethylammonium bromide. PS was composed primarily of carbohydrate and contained less than 1% (wt/wt) protein and nucleic acids. The protective capacity of passively transferred anti-PS was evaluated in a murine burn wound sepsis model. Anti-PS antibody was found to offer high levels of protection (P less than or equal to 0.02) against a low challenge dose of K. pneumoniae KP1-0. The 50% lethal dose for mice which received anti-PS antibody was increased from 10- to 40-fold over that for mice which received normal rabbit serum. Anti-PS antibody was found to be most effective at reducing mortality when administered before the challenge. In experiments designed to monitor the course of the infection, anti-PS was found to both delay the onset of bacteremia and reduce bacterial counts in the blood. Optimal protection against fatal burn wound sepsis was obtained by the use of a combined antibiotic and passive antibody therapy regimen.
Genetic and biochemical evidence for a siderophore-dependent iron transport system in Corynebacterium diphtheriae
Authors: Russell L M , Cryz S J , Holmes R K
Published: January 2020

During growth under conditions of iron deprivation, Corynebacterium diphtheriae secreted a siderophore into the culture medium. This extracellular siderophore was necessary for rates of iron uptake at pH 8.0 by C. diphtheriae C7 and related strains. We isolated a mutant of C. diphtheriae C7(beta), strain HC6, which did not make the corynebacterial siderophore. Strain HC6 grew very poorly, even under high-iron conditions, and had a severe defect in iron transport. Both growth and iron uptake by strain HC6 were greatly stimulated by the corynebacterial siderophore. We used strain HC6 to develop a bioassay for the corynebacterial siderophore and to look for other potential siderophores for C. diphtheriae. Among the purified phenolate and hydroxamate siderophores tested, only aerobactin was able to stimulate the growth of strain HC6. Partial purification of the corynebacterial siderophore was achieved. The siderophore did not give positive reactions in the Arnow test for phenolates or the Csaky test for hydroxamates and may have a novel chemical structure.
Pilus-mediated adherence of Escherichia coli K1 to human oral epithelial cells
Authors: Clegg H , Guerina N , Langermann S , Kessler T W , Guerina V , Goldmann D
Published: January 2020

We examined the effect of host age and health status on the adherence of mannose-sensitive piliated Escherichia coli K1 to human oral epithelial cells. Mannose-sensitive piliated bacteria adhered in comparable numbers to newborn, older infant, and adult cells (125 +/- 61, 198 +/- 54, and 139 +/- 69 bacteria per cell, respectively). Prematurity and serious illness did not alter adherence in newborns. The increased susceptibility of premature newborns to E. coli K1 cannot be explained by enhanced epithelial cell adherence.
Influence of multiple genes on the magnitude of the antibody response to bacterial polysaccharide antigens
Authors: Baker P J , Rudbach J A , Prescott B , Caldes G , Evans C , Stashak P W
Published: January 2020

Studies conducted with F1 and F2 progeny of crosses between strains of inbred mice that differ greatly in their capacity to make an antibody response to type III pneumococcal polysaccharide, dextran B-1355, and lipopolysaccharide from Escherichia coli 0113 have shown that multiple genes influence the magnitude of the antibody response to these antigens. Other studies with hybrids derived from crosses between C3H/HeJ, CBA/N, and RIIIS/J mice have indicated that the genetic defects characteristic of these strains of mice are dissimilar and unlinked and that autosomal, as well as X-linked, genes control serum immunoglobulin M in unimmunized mice.
Zinc concentration and survival in rats infected with Salmonella typhimurium
Authors: Tocco-Bradley R , Kluger M J
Published: January 2020

Percent survival was measured in male rats injected intravenously with live Salmonella typhimurium when plasma and tissue zinc levels were manipulated. Alzet pumps implanted intraperitoneally infused zinc gluconate or sodium gluconate (controls) from the onset of infection to 72 h postinfection. Plasma and tissue zinc levels were manipulated by infusing (i) 180 micrograms of Zn per h to achieve supranormal plasma and tissue zinc concentrations, (ii) 120 micrograms of Zn per h to prevent the infection-induced fall and to maintain plasma zinc levels at noninfection levels while raising tissue levels above that of infected controls, and (iii) 30 micrograms of Zn per h to increase tissue zinc levels while allowing the infection-induced decrease in plasma zinc. Preventing the fall in plasma zinc while raising liver zinc to supranormal levels enhanced rather than reduced percent survival; raising plasma and liver zinc to supranormal levels returned survival to control levels. Loading the liver with an excess of zinc without changing plasma zinc (30 micrograms of Zn per h) did not increase percent survival in the infected host. Pretreatment or administration of zinc at the time of infection led to increased percent survival compared with administration of zinc 4 h after the onset of infection.
Modifying effects of exercise on clinical course and biochemical response of the myocardium in influenza and tularemia in mice
Authors: Ilbäck N G , Friman G , Beisel W R , Johnson A J , Berendt R F
Published: January 2020

For a study of the interactions of strenuous physical exercise (daily swimming to exhaustion) and a viral as compared with a bacterial infection with regard to the clinical course and the biochemical response of the myocardium, influenza and tularemia of similar lethality were used in mice. In both infections, expected infection-induced catabolic alterations in the ventricular myocardium were evident 2 days before median lethality was achieved, with a more pronounced wasting in influenza than in tularemia. Exercise before inoculation (preconditioning) was beneficial in that the catabolic effects of both infections were limited and lethality in influenza was reduced. Thus, the myocardial protein-degrading effect of influenza did not occur with preconditioning, and oxidative tissue enzyme activities decreased less. In tularemia, cytochrome c oxidase activity was fully preserved with preconditioning, and activation of catalase was less pronounced. Exercise during ongoing infection counteracted the infection-induced decrease in the activities of glycolytic and oxidative enzymes in tularemia, but lethality and bacterial counts in the spleen were uninfluenced. Conversely, exhaustive exercise in influenza increased lethality and had no significant effect on cardiac enzymes. These exercise models caused no major alterations in activation of lysosomal enzymes (beta-glucuronidase and cathepsin D).