bluuebunny/crossref_metadata_2025 huggingface dataset:
Liability to hydrophobic and charge interaction of smooth Salmonella typhimurium 395 MS sensitized with anti-MS immunoglobulin G and complement
Authors: Stjernström I , Magnusson K E , Stendahl O , Tagesson C
Published: January 2020

Sensitization of smooth Salmonella typhimurium 395 MS bacteria with hyper-immune anti-MS immunoglobulin G (IgG) antibodies increased the liability to hydrophobic interaction as assessed by the affinity for a column of Octyl-Sepharose. After sensitization, the material originally eluted with 1 M (NH4)SO4 in a 0.01 M phosphate buffer (pH 6.8) was not desorbed until the ionic strength was reduced to nil, and 0.1% (vol/vol) Triton X-100 in the 0.01 M phosphate buffer was used as eluant. Furthermore, by including positively charged bis-trimethylamino-polyethylene glycol (PEG) or negatively charged bis-sulfoamino-PEG in an aqueous two-phase system of dextran T500 and PEG 6000, the partition of the IgG-sensitized bacteria was affected by either of the polymers, whereas that of the parent bacteria was not. The hydrophobic effect of IgG binding was enhanced by complement. With heat-inactivated complement, the effect of IgG was diminished. The F(ab')2 fragment showed a much lower capacity to promote a hydrophobic interaction than the complete IgG molecule.
Rabbit intestinal fluid stimulation by an enterotoxigenic factor of Staphylococcus aureus
Authors: Koupal A , Deibel R H
Published: January 2020

An exoprotein of Staphylococcus aureus 100 that elicited a positive ileal loop response in the rabbit model was investigated in this study. The protein, as it occurred in the culture supernatant fluid, could be detected initially in the late log phase of growth under aerobic and anaerobic conditions. It was stable under acidic conditions to pH 2.0 after 24 h at 4 degrees C. Thirty-minute treatments at 80 degrees C destroyed the ileal loop activity whereas similar trials at 70 degrees C had no effect. Although preparations of staphylococcal enterotoxins purified by other investigators did not produce positive ileal loops, the enterotoxigenic activity of the S. aureus 100 supernatant fluid could be neutralized by antisera prepared against enterotoxins A and B. Throughout purification studies, the active moiety reacted serologically with antiserum A. Polyacrylamide gel electrophoresis of the partially purified protein produced migration patterns nearly identical to those of enterotoxin A.
New test for endotoxin potency based upon histamine sensitization in mice
Authors: Bergman R K , Milner K C , Munoz J J
Published: January 2020

The results of a test of endotoxic potency based upon the development of histamine hypersensitivity in mice were compared with the results obtained by testing the same materials for pyrogenicity in rabbits and lethality for chicken embryos (CELD50). The results of the histamine hypersensitization test (HHT) correlated well with those of the other two tests. The sensitivity of the HHT was about the same as that of the CELD50 assay. The HHT may provide a relatively inexpensive, fast, and reliable assay method for endotoxin laboratories that do not have the facilities for the more elaborate assays.
Suppression of immunity to Mycobacterium lepraemurium infection
Authors: Lefford M J , Mackaness G B
Published: January 2020

After injection of 10(8) live Mycobacterium lepraemurium (MLM) into the left hind footpad of mice, there is development of local swelling attributable to a granuloma of the cell-mediated immunity type. Concomitant intravenous inoculation of live MLM delays and may even suppress footpad swelling, the effects being proportional to the intravenous dose of organisms. Concomitant footpad infection and intravenous inoculation of 10(9) dead MLM also delays footpad swelling, but over a period of months the feet become excessively swollen. The excessive swelling is due to local enhancement of infection as evidenced by an increase in the number of MLM per footpad. Attempts were made to prevent such immunosuppression by splenectomy or treatment with BCG. Splenectomy was entirely without effect, but 10(7) live BCG administered intravenously 2 to 4 weeks before dead MLM prevented enhancement of infection. The mediator of the immunosuppressive mechanism that results in enhanced infection remains to be elucidated, but it is unlikely to be antibody or immune complexes.
Potentiation of mouse peritoneal macrophage antibacterial functions by treatment of the donor animals with the methanol extraction residue fraction of tubercle bacilli
Authors: Gallily R , Douchan Z , Weiss D W
Published: January 2020

Administration to inbred mice of the methanol extraction residue fraction of tubercle bacilli by some, but not by all, routes affected markedly the in vitro phagocytic and antibacterial capacities of their peritoneal macrophages harvested several days to weeks after treatment. Phagocytosis of living [3H]thymidine- labeled Staphylococcus albus and Staphylococcus aureus organisms, but not of Listeria monocytogenes, was markedly enhanced. Uptake of the deoxyribonucleic acid precursor thymidine by the phagocytized staphylococci was consistently and significantly inhibited in macrophages taken from methanol extraction residue-treated donors. Such macrophages also displayed a significant facility to reduce the viability of intracellular S. albus and L. monocytogenes, but not of S. aureus, under the present experimental conditions.
Cross-immunity between Hammondia and Toxoplasma infections in mice and hamsters
Authors: Christie E , Dubey J P
Published: January 2020

Cross-immunity between six strains of Hammondia hammondi and the M-7741 strain of Toxoplasma gondii was studied in mice and hamsters. Mice and hamsters were inoculated orally with 10(5) H. hammondi oocysts. All mice and hamsters survived. Four weeks later, they were challenged with 1 to 10(5) mean lethal doses (LD50) of the Toxoplasma oocysts. Animals that died were necropsied. Survivors were killed 30 days after challenge inoculation, and the number of cysts in brain and musculature was determined and compared with that of animals that were not immunized with H. hammondi. In one experiment, 36 mice were immunized with each of three H. hammondi strains. Four weeks later the mice were challenged with 1 to 10(5) LD50 doses of T. gondii oocysts. Of 108 mice immunized with H. hammondi, 103 survived challenge with Toxoplasma oocysts for 30 days, whereas only 3 of 36 unimmunized mice survived with similar doses of Toxoplasma oocysts. Fewer Toxoplasma cysts were found in mice immunized with H. hammondi than in unimmunized mice. In another experiment groups of six hamsters were each immunized with one of six H. hammondi strains and then challenged with 10(5) LD50 Toxoplasma oocysts. All unimmunized hamsters died between 9 and 13 days after inoculation. Percent protection in the various groups of immunized hamsters was: 100, 84, 66, 66, 50, and 33.
Experimental infection of human leukocytes with parainfluenza 1 (6/94) virus
Authors: Bogen C , Gilden D H , Wroblewska Z , Wolinsky J S
Published: January 2020

Parainfluenza 1 (6/94) virus replicated in both unstimulated and phytohemagglutinin (PHA)-stimulated human peripheral blood leukocytes (PBL). After exposure of PBL to 6/94 virus at a multiplicity of infection of 1, the presence of viral antigen was demonstrated by immunofluorescence in the cytoplasm of less than 1% of unstimulated PBL and 1 to 5% of macrophages. Small amounts (less than 50 mean egg infective doses per ml in most instances) of cell-free virus were present in 18 of 30 (60%) cell cultures tested from 3 to 8 days postinfection. Cell-free virus peaked 6 days postinfection. Virus replication was enhanced in PHA-stimulated cells. Approximately 1 to 10% of PHA-stimulated PBL contained viral antigen as evidenced by immunofluorescence, and cell-free virus was present in 19 of 25 (76%) of the cell cultures tested from 3 to 8 days postinfection. Paramyxovirus nucleocapsids and tubular aggregates were seen in the cytoplasm of approximately 5% of PHA-stimulated PBL and were visualized only in lymphocytes. No other unusual intracytoplasmic or intranuclear structures were seen.
Selective in vitro response of thymus-derived lymphocytes from Treponema pallidum-infected rabbits
Authors: Pavia C S , Folds J D , Baseman J B
Published: January 2020

The blastogenic response of nylon wool-separated peripheral-blood lymphocytes from Treponema pallidum-infected rabbits was tested in vitro with mitogens and T. pallidum antigens. The mitogenic response of the enriched T-cell population to concanavalin A and phytohemagglutinin was depressed during the first 3 to 4 weeks of infection, similar to the pattern observed with unfractionated cells. Shortly thereafter, levels of blastogenesis returned to values of uninfected cultures. Enhanced blast transformation was seen immediately when purified T-cells from infected rabbits were exposed in vitro to T. pallidum antigens. Although these relatively high levels of blastogenesis were maintained for the duration of the experiment, cultures of unfractionated lymphocytes from infected rabbits did not exhibit an increased blastogenic response to the same antigen preparation until 3 to 4 weeks after infection. Autologous serum from infected rabbits decreased the lymphocyte response to T. pallidum antigen. The stimulatory effects of anti-immunoglobulin G and lipopolysaccharide on nylon wool-fractionated or unfractionated lymphocytes from both infected and control rabbits were similar throughout the course of infection. During the first 6 weeks of experimental disease, there was a 25 to 31% increase in the number of lymphocytes circulating in the peripheral blood of T. pallidum-infected rabbits.
Binding of lectins to Streptococcus mutans cells and type-specific polysaccharides, and effect on adherence
Authors: Hamada S , Gill K , Slade H D
Published: January 2020

The lectin concanavalin A (Con A) agglutinated the cells of 13 of 15 strains of the seven serotypes of Streptococcus mutans in an 18-h incubation period. Strains of types a, d, f, and g agglutinated within 2 h. Strains of a, d, and f were also agglutinated in 2 h by the castor bean lectin RCA. S. sanguis, S. salivarius, S. bovis, Actinomyces viscosus, A. naeslundii, and Lactobacillus plantarum were agglutinated within 2 h. The S. mutans type f polysaccharide was precipitated by Con A. The a, b, c, d, and e polysaccharides were not precipitated. Glucan from d and e strains of S. mutans and dextran T2000 were also precipitated by Con A. D-glucose inhibited the agglutination of type f cells by Con A and the agglutination of type d cells by D-galactose. The quantity of [acetyl-3H]Con A bound was not proportional to the degree of agglutination. Cells grown in sucrose medium bound more Con A than those grown in glucose medium. After treatment with dextranase, the sucrose-grown cells bound two- to fourfold more Con A. The binding of Con A to the type-specific polysaccharide or to teichoic acid could not be determined by the use of specific antibody due to the binding of Con A to the antibody globulin on the cell surface. Con A bound to S. mutans cells did not inhibit the activity of cell-bound glucosyltransferase, glucan synthesis, and in vitro adherence. Bound Con A also did not inhibit the ability of heat-treated cells to bind glucosyltransferase, synthesize glucan, and produce in vitro adherence.
Adherence of
Veillonella
Species Mediated by Extracellular Glucosyltransferase from
Streptococcus salivarius
Authors: McCabe R. M. , Donkersloot J. A.
Published: January 2020

The effect of extracellular products from
Streptococcus salivarius
on sucrose-dependent adherence to smooth surfaces by other oral bacteria was studied in vitro. Strains of
Streptococcus mitis, Streptococcus pyogenes
, and
Veillonella parvula
without innate ability to adhere to a steel wire were able to do so when incubated with sucrose and cell-free culture fluid from
S. salivarius
strains 9759, 25975, CNII, and MEPI. These culture fluids synthesized more adherent material and water-insoluble glucan than those from
Streptococcus mutans
C67-1 and seven other
S. salivarius
strains. Among the
S. salivarius
strains, glucosyltransferase (GT; dextransucrase, EC 2.4.1.5) activity varied more than 100-fold. Cells of
Veillonella
and
S. mitis
S3 that had been incubated in culture fluids from
S. salivarius
25975 and 9759, respectively, and then washed adhered upon subsequent incubation with sucrose. This was due to adsorbed GT because (i) the adherence was sensitive to dextranase; (ii) it was observed only with the high-GT culture fluids; (iii) it was dependent on sucrose; and (iv) the washed
Veillonella
cells synthesized glucan, but not fructan, from sucrose. These results suggest that sucrose-dependent adherence of bacteria without such innate ability can be mediated by (i) entrapment in insoluble glucan synthesized by
S. salivarius
culture fluids, and (ii) prior adsorption of GT from
S. salivarius
culture fluids. The possibility that GT formed by high-yield strains of
S. salivarius
is distributed through the mouth by the action of salivary flow and contributes to sucrose-dependent adherence and plaque formation is considered.
Respiratory infection in mice with sialodacryoadenitis virus, a coronavirus of rats
Authors: Bhatt P N , Jacoby R O , Jonas A M
Published: January 2020

Sialodacryoadenitis virus (SDAV), a coronavirus of rats, evoked both serum neutralization and complement fixation antibody responses when inoculated intranasally in mice. Weanling gnotobiotic CD-1 mice inoculated intranasally with 10(3.0) mean tissue culture infective doses of SDAV remained asymptomatic. Virus was recovered from the nasopharynx, trachea, and lung from day 2 to day 7. Viral antigen was readily detected by indirect immunofluorescence in the lung but rarely in the nasopharynx. Infected mice developed interstitial pneumonia. Susceptible mice contact exposed to experimentally infected mice developed antibody to SDAV. Epizootiological studies indicated that retired breeder mice can have complement-fixing antibody to SDAV and mouse hepatitis virus (MHV) in the absence of MHV infection. These studies show that SDAV is infectious for mice and can be a pathogen for the respiratory system. Thus, SDAV infection of mice may be responsible for spurious seroconversions to MHV.
Antigens of
Streptococcus mutans
: Isolation of a Serotype-Specific and a Cross-Reactive Antigen from Walls of Strain V-100 (Serotype
e
)
Authors: Wetherell J. R. , Bleiweis A. S.
Published: January 2020

Two cell wall-associated polysaccharide antigens were extracted from purified cell walls of
Streptococcus mutans
serotype
e
strain V-100. One of these purified antigens (I) is specific for serotype
e
, whereas the other (II) has antigenic determinants reactive with both heterologous anti-serotype
c
serum (GS-5) and the homologous (
e
) serum. When crude formamide extracts of V-100 cell walls were loaded onto a Cellex-D column and eluted with a linear gradient of ammonium carbonate (0.02 to 0.40 M), the two products mentioned above could be recovered. The purified, antigenically reactive products (I and II) were each composed only of rhamnose and glucose in approximately a 2:1 molar ratio. Immunoelectrophoresis of the crude formamide extract, peak I, and peak II showed the purified fractions to have opposite mobilities and the crude extract to have a mobility that encompassed both purified peaks when reacted with homologous antiserum (V-100). When these three fractions were immunoelectrophoresed and reacted with heterologous anti-serotype
c
serum (GS-5), only the anodic portion of the crude V-100 formamide extract and purified peak II formed precipitates. Ouchterlony analysis with homologous antiserum produced precipitin patterns between the crude formamide extract and both purified peaks, indicating complete identity. However, only crude extracts of V-100 and the purified peak II material reacted with heterologous (
c
) antiserum; peak I did not cross-react in these Ouchterlony assays. Hapten inhibition studies revealed that a β-glucosyl moiety is the immunodeterminant for serotype
e
and is present on each purified fraction. The basis of the cross-reaction between anti-
c
sera and the purified antigen II of
e
is discussed.
Immune effector cell activity in canines: failure to demonstrate genetic restriction in direct antiviral cytotoxicity
Authors: Ho C K , Babiuk L A , Rouse B T
Published: January 2020

Experiments were undertaken to establish whether the cytotoxic activity of canine immune effector cells against viral antigens was affected by the genotype of the target cell (genetic restriction). Puppies from three different breeds were infected with vaccinia virus, and the peripheral blood leukocytes were collected at various times for measurement of their cytotoxicity against autologous and heterologous vaccinia virus-infected and uninfected skin fibroblasts. In all cases cytotoxicity only occurred against virus-infected targets, and there was no consistent evidence of preferential killing of autologous targets. Several indirect approaches were used to demonstrate that direct, presumably T cell, cytotoxicity was being measured rather than antibody-dependent cell cytotoxicity. On the basis of the evidence from cross mixed-lymphocyte assays and cell-mediated lympholysis assays, the dogs were shown not be be identical with respect to their histocompatibility antigens. The significance of our findings to the phenomenon of genetic restriction as observed for mouse-derived immune effector cells is briefly discussed.
Cell-mediated immune responses of guinea pigs to an inactivated phase I Coxiella burnetii vaccine
Authors: Kishimoto R A , Johnson J W , Kenyon R H , Ascher M S , Larson E W , Pedersen C E
Published: January 2020

The ability of a killed phase I Coxiella burnetii vaccine to induce cell-mediated immune responses in guinea pigs was studied. Cell-mediated immune responses were assessed by the inhibition of macrophage migration and lymphocyte transformation assays. The macrophage migration response occurred rapidly and was detected at high levels, but was relatively short-lived. In contrast, the lymphocyte transformation response developed more slowly, and persisted for a longer period. The vaccine, given in a single dose or in two doses 1 week apart, protected guinea pigs from a subsequent virulent challenge.
Effective immunity to dental caries: dose-dependent studies of secretory immunity by oral administration of Streptococcus mutans to rats
Authors: Michalek S M , McGhee J R , Babb J L
Published: January 2020

Rats (COBS/CD) provided Formalin-killed Streptococcus mutans 6715, C211 in their drinking water (10(8) to 10(9) equivalent colony-forming units [CFU] per ml) had high levels of specific antibodies in saliva, colostrum, and milk. Rats provided a lower concentration of S. mutans antigen (10(7) CFU per ml) in water had agglutinin titers in secretions that were similar to those in controls. Gnotobiotic rats provided S. mutans antigen in food (10(7) to 10(8) equivalent CFU per g of diet) manifested a secretory immune response as evidenced by the presence of specific immunoglobulin A antibodies in saliva, colostrum, and milk. Gnotobiotic rats provided a higher concentration of antigen (10(9) CFU per g) in food had levels of specific antibodies in their secretions that were similar to those in controls. No significant antibody activity to S. mutans was observed in sera of any group of animals. Furthermore, the presence of specific salivary immunoglobulin A antibodies in gnotobiotic rats correlated with a reduction in the level of plaque, numbers of viable S. mutans in plaque, and levels of S. mutans-induced dental caries. This paper discusses the importance of antigen dosage for induction of a secretory immune response that is protective against S. mutans-induced dental caries.
Identification of the Virulence-Associated Antigen on the Surface Fibrils of
Actinomyces viscosus
T14
Authors: Cisar John O. , Vatter Albert E. , McIntire Floyd C.
Published: January 2020

Actinomyces viscosus
T14V is virulent (V) for monoinfected rats, causing periodontal disease and bone loss, whereas,
A. viscosus
T14AV, a mutant strain, is avirulent (AV). Surface antigens from the T14V and T14AV strains were prepared by lysozyme digestion of cell walls and were compared by immunodiffusion against antisera to T14V and T14AV whole cells. The V-associated antigen (V-antigen) was detected readily in the T14V, but not readily in the T14AV cell wall extract. Antiserum specific for the V-antigen was prepared by absorbing anti-
A. viscosus
T14V serum with cell walls from the T14AV strain. This antiserum was used in the indirect peroxidase-labeled antibody technique to localize the V-antigen on the bacterial cell surface at the ultrastructural level. With whole bacterial cells, the V-antigen was found on fine fibrils and was detected in both the T14V and T14AV strains. The presence of V-antigen on the AV strain was supported by the demonstration of antibodies against the V-antigen in anti-
A. viscosus
T14AV serum. Examination of isolated bacterial cell walls revealed a greater amount of fibrils and V-antigen on the T14V cell wall than on the T14AV cell wall. The data suggest that the presence of V-antigen represents a quantitative rather than a qualitative difference between the V and the AV strains of
A. viscosus
T14. Samples of human plaque were examined, and the V-antigen was found to be a specific marker for the fibril-containing layer of certain plaque bacteria, which are probably strains of
A. viscosus
or
A. naeslundii.
Phytohemagglutinin enhancement of dengue-2 virus replication in nonimmune rhesus monkey peripheral blood leukocytes
Authors: Marchette N J , Halstead S B
Published: January 2020

Phytohemagglutinin treatment of peripheral blood leukocytes from dengue nonimmune monkeys enhanced dengue-2 virus replication. Enhancement was due primarily to an increase in the number of infected cells. Destruction of mononuclear phagocytes with silica did not significantly inhibit virus replication in phytohemagglutinin-treated cultures. Pokeweed mitogen, concanavalin A, and streptolysin O stimulated increased deoxyribonucleic acid synthesis in monkey leukocytes but did not enhance virus replication. None of the mitogens significantly affected virus replication in cultures of dengue-immune monkey peripheral blood leukocytes.
Cellular Adherence, Glucosyltransferase Adsorption, and Glucan Synthesis of
Streptococcus mutans
AHT Mutants
Authors: Koga Toshihiko , Inoue Masakazu
Published: January 2020

Streptococcus mutans
AHT mutants M1, M2, and M13 failed to adhere to a glass surface, whereas mutants M9 and M35 exhibited decreased and increased adherence, respectively, as compared with the parent strain, when grown in sucrose broth. Extracellular glucosyltransferase prepared from glucose-grown cultures of the adherent strains (wild type, M9, and M35) induced adherence of heat-killed cells of the homologous and heterologous streptococcal strains as well as of
Escherichia coli
K-12 and uncoated resin particles. The glucosyltransferase was adsorbed on all the streptococcal cells and glucan-coated resins, but not on
E. coli
cells and the uncoated resins. Glucosyltransferase from the nonadhering mutants (M1, M2, M13) neither was significantly adsorbed on nor induced adherence of any of the cells and resins. Cell-free enzymes from the glucose-grown adherent strains produced water-soluble and water-insoluble glucans, whereas those from the nonadhering mutants produced only water-soluble glucans. Small amounts of alkali-soluble, cell-associated glucan were recovered from the sucrose-grown nonadhering mutants. Thus, the relative proportions of glucosyltransferase isozymes elaborated by the
S. mutans
mutants, insofar as they affect the physico-chemical properties of the glucans produced, seem to determine the adherence abilities of the cells. The adsorption of glucosyltransferase on glucan molecules on the cell surface is not required for the adherence of
S. mutans
, but de novo glucan synthesis is important in the adherence process.
Unsustained multiplication of treponema pallidum (nichols virulent strain) in vitro in the presence of oxygen
Authors: Sandok P L , Jenkin H M , Matthews H M , Roberts M S
Published: January 2020

Treponema pallidum (Nichols virulent strain) was incubated with or without oxygen using a modified medium supplemented with reduced glutathione and a variety of nutrients (PRNF10-B). Two- to fourfold increases in treponemal numbers were observed in cultures without mammalian cells within 96 h of incubation under 5 to 6% oxygen. Treponemal motility and multiplication were maintained more satisfactorily in cultures that were diluted and transferred daily, using an equal volume of fresh medium. Treponemes incubated without oxygen did not significantly increase in number. Virulent microorganisms were detected for at least 96 h in the cell-free system. In the presence of 3 to 4% oxygen, two- to fivefold increases in treponemal numbers were observed in the supernatant fluids of cultures containing human prepuce cells after 48 to 120 h at 35 degrees C. Without oxygen, treponemal numbers rarely approached a threefold increase. Virulent treponemes were detected by the rabbit skin lesion test after at least 120 h in vitro. Regardless of the system of incubation, increases in treponemal numbers could not be sustained for longer than 120 h, and treponemal virulence decreased as a function of time in vitro.
Humoral bactericidal systems: nonspecific and specific mechanisms
Authors: Skarnes R C
Published: January 2020

Bactericidal systems in normal serum from month-old rabbits and guinea pigs were characterized in terms of activity against rough- and smooth-phase species of gram-negative bacteria. Killing of the rough strains in the absence of natural antibody required complement and at least one additional nonspecific component exhibiting lability to freezer storage and to heating at 52 degrees C. Bactericidal action against the smooth-phase organisms, on the other hand, appeared to require natural antibody in addition to complement and the labile component. Both nonspecific and specific bactericidal systems were also functional in normal serum from adult animals. In immune systems, the labile nonspecific component was not essential for bactericidal activity. Whereas immune systems were subject to inhibition by homologous endotoxins, the normal serum bactericidal systems were not, indicating that the natural antibodies in normal serum were specific for surface antigens other than the O-somatic polysaccharides. The significance of these observations is discussed in relation to probable complement pathways that mediate killing in each of the systems described.
Production of antibodies to human interferons in mice
Authors: Dalton B J , Ogburn C A , Paucker K
Published: January 2020

Neutralizing antibodies were raised in mice that had been inoculated repeatedly with moderate quantities of human leukocyte interferon highly purified by affinity chromatography on immobilized anti-interferon globulins. Interferon preparations of lesser purity sensitized the mice to subsequent inoculations of interferon and almost invariably caused death before anti-interferon titers developed. Antibody-purified interferon stabilized by sodium dodecyl sulfate was a superior antigen to interferon that had received mouse serum albumin as an additive. The amount of antibody could be augmented by experimental induction of ascites. The antibodies specifically neutralized leukocyte and lymphoblastoid interferons but not those interferons obtained cultures of human foreskin fibroblasts, embryonic kidney cells, and amnion cells.
Inhibition of Neisseria gonorrhoeae by aerobic and facultatively anaerobic components of the endocervical flora: evidence for a protective effect against infection
Authors: Saigh J H , Sanders C C , Sanders W E
Published: January 2020

The ability of aerobic and facultatively anaerobic endocervical flora to inhibit the growth of Neisseria gonorrhoeae in vitro was assayed. Factors influencing the occurrence of inhibitory components of the flora in vivo were evaluated. Endocervical swabs were obtained from 229 women at a local venereal disease clinic. Endocervical flora and N. gonorrhoeae were isolated and identified, and the ability of the flora to inhibit the growth of N. gonorrhoeae was determined by an agar overlay assay. Results revealed the most active inhibitors to be streptococci, staphylococci, and lactobacilli, in that order. Among only those women harboring inhibitory endocervical flora, inhibitory lactobacilli were recovered from fewer women infected with N. gonorrhoeae than uninfected women (P less than 0.05). Among women having contact with an infected partner, those who subsequently developed gonorrhea were less likely to have inhibitory lactobacilli than those who did not become infected (P less than 0.05). No other significant differences in the composition of the inhibitory flora were noted between infected and uninfected women. During the 2 weeks following menses, recovery of inhibitory lactobacilli on culture was highest, whereas recovery of N. gonorrhoeae was lowest. These observations suggest that the presence of certain lactobacilli may reduce risk of acquisition of N. gonorrhoeae following exposure to infected partners and that the potential protective effect may be greatest during the 2 weeks after menses.
Cell-associated levan of Actinomyces viscosus
Authors: Warner T N , Miller C H
Published: January 2020

Actinomyces viscosus ATCC 15987 was examined for the presence of cell-associated levan by absorption of myeloma proteins with antilevan activity and direct immunofluorescence. Levan was not detectable on the surface of glucose-grown A. viscosus, but after a brief incubation of these cells with 5% sucrose, they were encapsulated with tenaciously adhering levan. The levan layer constituted between 0.02 and 0.03% of the cell dry weight. In contrast, sucrose-grown A. viscosus cells possessed a low level of cell-associated levan, which was only moderately increased by incubation in sucrose and which partially existed as a loose slime rather than a tenacious capsule.
Vole agent identified as a strain of the trench fever rickettsia, Rochalimaea quintana
Authors: Weiss E , Dasch G A , Woodman D R , Williams J C
Published: January 2020

The vole agent described by Baker in 1946 was studied as an example of a bacterium that has been mistakenly regarded a rickettsia. Unlike rickettsiae, the vole agent killed chicken embryos with great irregularity, multipled primarily at the surface of avian or mammalian cells and not intracellularly, produced colonies rather than plaques on chicken embryo monolayers under agar, and developed small colonies after 4 to 7 days of cultivation on blood plates. It was most conveniently cultivated on monolayers of irradiated L cells and was purified by minor modifications of the Renografin gradient procedure used for rickettsiae. It actively catabolized glutamate, glutamine, succinate, and pyruvate, but not glucose or glucose-6-phosphate. Enzymatic activities of cell extracts were consistent with above findings. The base ratio (molar percent guanine plus cytosine) of its deoxyribonucleic acid was shown to be 39, which was identical to the base ratio of the deoxyribonucleic acid of Rochalimaea quintana tested simultaneously. Serological studies indicated no cross-reactivity with Rickettsia tsutsugamushi, but strong cross-reaction with R. quintana was observed when a hyperimmune rabbit serum and a convalescent human serum were tested. We conclude that the vole agent is a strain of the trench fever rickettsia, R. quintana.
Experimental infection of mouse peritoneal mesothelium with scrub typhus rickettsiae: an ultrastructural study
Authors: Ewing E P , Takeuchi A , Shirai A , Osterman J V
Published: January 2020

The infection cycle of Rickettsia tsutsugamushi in mouse peritoneal mesothelial cells, observed late in the course of an established infection, intimately involved the host cell plasma membrane. Organisms multiplied in the cytoplasm, moved to the cell periphery, and acquired a host-membrane coat as they budded from the cell surface. Rickettsiae enveloped by this membrane entered other mesothelial cells, apparently by a phagocytic mechanism. Organisms escaped from the phagocytic vacuole as the vacuole membrane and host membrane coat disintegrated. Free rickettsiae replicated by binary fission in the cell cytoplasm. Rickettsial infection of mesothelial cells induced conspicuous cellular hypertrophy with increased numbers of unaltered cytoplasmic organelles.
Adherence of Bacteroides fragilis in vivo
Authors: Onderdonk A B , Moon N E , Kasper D L , Bartlett J G
Published: January 2020

The ability of the encapsulated species Bacteroides fragilis to adhere to rat peritoneal mesothelium was compared to the adherence of unecapsulated strains of Bacteroides (B. distasonis, B. vulgatus, B. thetaiotaomicron, B. ovatus, and B. "other"). Adherence was assayed by attaching plexiglas plates containing 8-mm holes to the peritoneal mesothelium of anesthetized rats. Cell suspension (0.25 ml) was incubated in each well, after which the suspension was aspirated, and a 4-mm punch biopsy was removed. Viable organisms adhering to the biopsy specimen were enumerated by plate count following washing of the biopsy tissue. It was found that B. fragilis adhered significantly better to mesothelial tissue (10(3.00) colony-forming units per biopsy) than unencapsulated species of Bacteroides (10(1.07) colony-forming units per biopsy). This effect was not due to differential oxygen sensitivity of the various inocula. Immunization of rats with capsular polysaccharide did not demonstrate decrease in the adherence of B. fragilis; however, preincubation of the mesothelium with purified capsular polysaccharide resulted in a substantial reduction in adherence. These results indicate that B. fragilis adheres to rat peritoneal mesothelium better than unencapsulated species and suggests that the capsular polysaccharide of B. fragilis plays some role in this increased adherence.
Inhibition of hemolysis by zinc and its reversal by L-histidine
Authors: Avigad L S , Bernheimer A W
Published: January 2020

Hemolysis induced by staphylococcal alpha-toxin, staphylococcal beta-toxin, streptolysin O, and streptolysin S was inhibited by zinc ions by virtue of inhibition of an early step in the events leading to lysis, presumably by preventing the lysins from attaching to the plasma membrane. In contrast, in hemolysis induced by Clostridium perfringens alpha-toxin and by perfringolysin O, a later step was inhibited by zinc. In hemolysis caused by saponin, lysolecithin, and Triton X-100, hemoglobin was precipitated by zinc ions as it was released from the erythrocyte. Inhibition by zinc was abolished by several amino acids of which L-histidine was the most effective.
Ribosomal Ribonucleic Acid Synthesis by Virulent
Treponema pallidum
Authors: Nichols J. C. , Baseman J. B.
Published: January 2020

Ribosomal ribonucleic acid (rRNA) synthesis by virulent
Treponema pallidum
was monitored by incorporation of [
3
H]uridine into trichloroacetic acid-precipitable counts and examination of radiolabeled rRNA on polyacrylamide gels. Verification that rRNA synthesis originated with
T. pallidum
was based upon co-electrophoresis with
Escherichia coli
rRNA, proportionate reductions in the amount of rRNA synthesized when numbers of treponemes were decreased, and inclusion of appropriate animal cell controls. The rate of treponemal rRNA synthesis was greater at temperatures of 37 and 39°C than at 33°C; rRNA synthesis was inhibited at 4 and 42°C and was effectively inhibited by actinomycin D. Kinetic experiments indicated that the majority of rRNA synthesis occurred early after extraction of treponemes from infected rabbit testicular tissue. Polyacrylamide gel profiles demonstrated the capacity of virulent
T. pallidum
to synthesize and process RNA to 23
s
, 16
s
, and 4 to 5
s
classes. Although motility of
T. pallidum
appeared unaffected during longer periods of incubation, pulselabeling experiments confirmed significant reductions in the rate of rRNA synthesis. When the effect of various environmental conditions upon rRNA synthesis was investigated, optimal synthesis was found to occur in an atmosphere of 20% oxygen whereas virtually no synthesis was observed under anaerobic or low-oxygen conditions.
Enhanced Resistance Against Junin Virus Infection Induced by
Corynebacterium parvum
Authors: Budzko Delia B. , Casals J. , Waksman B. H.
Published: January 2020

The effects of intraperitoneal administration of
Corynebacterium parvum
on the course of Junin virus infection in mice were investigated. This treatment produced enhanced resistance to the virus infection, evidenced by an increase in both survival times and the proportion of survivors. The protective effect was dependent upon the dose of
C. parvum
, and 280 μg/g of body weight was found to be the optimal dose. In various experiments, about 80% of the infected animals receiving this dose survived, whereas survival ranged between 0 and 20% among untreated infected mice. Maximal protection was afforded by
C. parvum
when administered simultaneously with the virus. A smaller but significant degree of resistance was induced by
C. parvum
given 3 or 6 days after infection.
C. parvum
injected before infection was ineffective. Viral titers measured in the brains of
C. parvum
-treated and untreated mice at various times after infection were found to be comparable. In addition, there were no significant differences between circulating-antibody titers measured either by neutralization tests or by complement fixation. Depression of the reticuloendothelial system by treatment with silica particles also resulted in enhanced resistance to Junin virus infection, suggesting that the protective effect of
C. parvum
is not likely to be due merely to its capacity to stimulate macrophages. The present data, highlighting that the presence of high titers of Junin virus and disease do not necessarily correlated, suggest that in mice this disease is not the consequence of cell damage caused directly by the virus but of a still undefined indirect mechanism induced by the virus, not necessarily mediated by macrophages.
Reversion of dextran sulfate-induced loss of antibacterial resistance by Bordetella pertussis
Authors: Finger H , Heymer B , Wirsing C H , Emmerling P , Hof H
Published: January 2020

Parenteral injection of dextran sulfate 500 (DS 500; 50 mg/kg of body weight) into mice caused a complete loss of resistance to a sublethal (2 X 10(3) to 5 X 10(3)) infection with Listeria monocytogenes. Such loss could be prevented by pretreatment of animals with 3 X 10(9) heat-killed Bordetella pertussis organisms (PO) 5 to 30 days before the administration of DS 500. The increased phagocytic capcity induced by PO was only exhausted when a fourfold dose of DS 500, effecting complete loss of antibacterial resistance (50 mg/kg ob body weight), was administered. Listeriosis in mice treated with DS 500 is characterized by rapid-progressive necro-purulent inflammation of liver and spleen, lack of mononuclear phagocyte response, and 100% lethality within 72 h after infection. In contrast, the time course, extent, and morphological characteristics of listeriosis in animals pretreated with PO before the DS 500 application were not significantly different from those of nonpretreated controls. Evidence is presented that the protective effect of PO is due to activation of the mononuclear phagocyte system, which without such treatment is blocked by the DS 500 administration. The data presented indicate that the protective effect of PO is due only in part to the endotoxic moiety of these bacteria. Differences in the course and morphology of listeriosis in animals with dysfunction of the mononuclear phagocyte system and in animals with deficiency of the cellular immune system are discussed.
Mediation of immunity to intracellular infection (Toxoplasma and Besnoitia) within somatic cells
Authors: Chinchilla M , Frenkel J K
Published: January 2020

Antigen-treated lymphocytes from immune hamsters specifically protected not only macrophages, but also cultured fibroblasts and kidney cells infected with Toxoplasma gondii or Besnoitia jellisoni. Macrophages were not necessary for the protection of fibroblasts and kidney cells. A mediator that inhibited the intracellular proliferation of these microbes was obtained from immune lymphocytes in contact with specific antigen. Again, macrophages were not necessary for the elaboration of this mediator or its activity in kidney cells or fibroblasts. The mediator was microbe and host specific, had a molecular weight between 4,000 and 5,000, was resistant to heating at 56 degrees C for 30 min, and was sensitive to chymotrypsin, but resistant to ribonuclease and deoxyribonuclease. A single injection of Besnoitia mediator afforded better protection to hamsters infected with Besnoitia than did antibody. Whereas antibody lysed extracellular organisms, the microbe-specific mediators conferred immunity not only on macrophages, but also on other cells of the body, apparently the first such demonstration.
Modifying Effect of Colicin on Experimental
Shigella
Keratoconjunctivitis
Authors: Streelman A. J. , Snyder I. S. , Six E. W.
Published: January 2020

The ability of colicinogenic bacteria and colicin to inhibit
Shigella sonnei
during the course of infection was studied. Infection of the guinea pig conjunctivae was used as the experimental model. In
S. sonnei
-infected guinea pig conjunctivae which were treated with a colicinogenic strain of
Escherichia coli
or with colicin, the number of
S. sonnei
cells was lower than in animals infected with
S. sonnei
but not treated. The decrease in the number of pathogenic organisms was associated with absence of disease. A noncolicinogenic strain of
E. coli
had no effect on production of disease in infected animals. Treatment with a colicinogenic strain of
E. coli
or colicin did not affect the production of disease or the numbers of organisms in an animal infected with a colicin-resistant strain of
S. sonnei
.
Interactions Between Macrophages of Guinea Pigs and Salmonellae II. Phagocytosis of
Salmonella typhimurium
by Macrophages of Normal Guinea Pigs
Authors: Wells Patricia S. , Hsu H. S.
Published: January 2020

Peritoneal macrophages from normal guinea pigs were allowed to phagocytize
Salmonella typhimurium
in vitro. The extent of phagocytosis was determined by quantitative viable counts of the bacteria released after lysis of the phagocytes with sodium deoxycholate. It was shown that the avirulent strain RIA of salmonellae was more susceptible to ingestion by macrophages than the virulent strain SR-11. The presence of immune serum in the phagocytic mixture greatly enhanced the extent with which strain SR-11 was phagocytized. Also, the virulent bacteria recovered from infected mice exhibited a greater resistance to phagocytosis than those maintained in artificial media.
Evidence on Possible Mycoplasma Etiology of Aster Yellows Disease II. Suppression of Aster Yellows in Insect Vectors
Authors: Whitcomb R. F. , Davis R. E.
Published: January 2020

Chlortetracycline or chloramphenicol (but not kanamycin, penicillin, or erythromycin), when administered in hydroponic solution to diseased aster, reduced the availability of the aster yellows (AY) agent to nymphs of
Macrosteles fascifrons
(Stål). Insects exposed to healthy plants whose roots were immersed in chlortetracycline were able to acquire AY agent from diseased plants the day after removal from the antibiotic-treated plants, but the latent period of the ensuing disease in the insects was prolonged. Chlortetracycline or tylosin tartrate blocked AY infection in nymphs injected with a mixture of antibiotic and the AY agent, but polymyxin, neomycin, vancomycin, penicillin, carbomycin, or chloramphenicol did not. All tetracyclines tested, methacycline, oxytetracycline, and chlortetracycline, produced a dramatic reduction in the ability of infected vectors to transmit AY agent. Tylosin tartrate also reduced transmission when injected into AY-transmitting vectors, but carbomycin, spectinomycin, cycloserine, penicillin, erythromycin, or kanamycin had no such effect. During the first 10 days after injection of tylosin tartrate or oxytetracycline into transmitting vectors, ability of the insects to transmit AY decayed rapidly. Transmission by insects injected with buffer alone, after decreasing the first day after injection, gradually returned to its normal level in less than 1 week. By 2 to 3 weeks after injection with tylosin or oxytetracycline, ability to transmit AY was regained by vectors. The results suggest that tetracycline antibiotics and tylosin tartrate inhibit multiplication of AY agent in the insect. The spectrum of antibiotic activity in the insect is consistent with the hypothesis that AY and other plant yellows diseases are caused by mycoplasma-like organisms.
Fractionation of Phenol Extracts from
Brucella suis
: Separation of Multiple Biologically Active Components
Authors: McGhee Jerry R. , Freeman Bob A.
Published: January 2020

Brucella suis
endotoxin prepared by a modification of Westphal's method was purified further by gel filtration and ion-exchange chromatography. The latter proved to be the most effective means of separating antigenic components associated with this fraction. All of the toxic activity was located in a single peak from carboxymethyl-Sephadex. Subsequent separation of this material on diethylaminoethyl (DEAE)-Sephadex indicated the presence of two or more toxic components in phenol extracts of
B. suis
. A factor which increases vascular permeability was separated by use of the ion exchanger DEAE-Sephadex, and was associated with the first peak. Its manifestations could be destroyed by heating at 60 C for 30 min or neutralized by reaction with specific antiserum. This permeability factor is believed to be distinct from other toxins which appear in column eluates and which can be assayed by skin induration.
Lipids of Parasitic and Saprophytic Leptospires
Authors: Johnson R. C. , Livermore B. P. , Walby Judith K. , Jenkin H. M.
Published: January 2020

The lipid composition of five parasitic and six saprophytic leptospires was compared. Lipids comprise 18 to 26% of the dry weight of the cells after chloroform-methanol extraction. No residual (bound) lipid was found after acid or alkaline hydrolysis of the extracted residue. The total lipid was composed of 60 to 70% phospholipid, and the remaining lipid was free fatty acids. The phospholipid fraction contained phosphatidylethanolamine as the major component, and phosphatidylglycerol and diphosphatidylglycerol were minor components with traces of lysophatidylethanolamine sometimes found. The major fatty acids of leptospires were hexadecanoic, hexadecenoic, and octadecenoic acids. Both the unusual
cis
-11-hexadecenoic acid and the more common
cis
-9-hexadecenoic acid were synthesized by the leptospires. Neither the parasitic nor the saprophytic leptospires can chain elongate fatty acids. However, they were capable of β-oxidation of fatty acids. Both groups of leptospires desaturate fatty acids by an aerobic pathway. When the parasite
canicola
was cultivated on octadecanoic acid, 87% of the hexadecenoic acid was the 11 isomer, whereas the saprophyte
semeranga
consisted of 10% of this isomer. In addition, the saprophytic leptospires contained more tetradecanoic acid than the parasites. No differences were observed in the lipid composition of virulent and avirulent strains of
canicola.
Ability of
Staphylococcus aureus
Cells to Bind Normal Human Immunoglobulin G
Authors: Virgilio A. R. , González P. C. , Munoz S. Nubia , Mendoza G. Silvia
Published: January 2020

Staphylococcus aureus
cells suspended in a human immunoglobulin G (IgG) solution adsorbed nearly 90% of the IgG; electron micrographs showed the cells enclosed in a thick, dense envelope of IgG.