bluuebunny/crossref_metadata_2025 huggingface dataset:
Isolation and characterization of minicell-producing mutants of Shigella spp
Authors: Gemski P , Griffin D E
Published: January 2020

Minicells are small, anucleate cells resulting from aberrant cell divisions at the polar ends of bacilli. We have isolated minicell-producing mutant strains of Shigella flexneri 2a (MC-I) and Shigella dysenteriae 1 (MC-V) after mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine. Microscopically, broth cultures of MC-I and MC-V were found to contain free minicells, normal cells, and filamentous cells with polar, attached minicells. Both strains retained their ability to provoke keratoconjunctivitis in guinea pigs and to invade HeLa cells. Purified suspensions of minicells containing less than one whole cell per 10(6) minicells were obtained by a combination of differential sedimentation and density gradient centrifugation (5 to 30% [wt/vol] linear sucrose gradients). Each MC-I minicell contained about 0.005 times the amount of deoxyribonucleic acid of one normal S. flexneri. The MC-V minicell had about 0.003 times the amount of deoxyribonucleic acid of one whole S. dysenteriae cell. Purified MC-V minicells were treated with polymyxin B to release Shiga toxin. Shiga toxin was readily detected in MC-V minicells by means of a microtiter HeLa cell cytotoxicity assay. Our findings indicate that such a minicell-producing alteration in the cell division cycle of shigellae has not significantly affected their virulence.
Impaired resistance to bacterial infection after tumor implant is traced to lactic dehydrogenase virus
Authors: Bonventre P F , Bubel H C , Michael J G , Nickol A D
Published: January 2020

A BALB/c mouse-passaged methylcholanthrene-induced fibrosarcoma tumor caused severe impairment of resistance to systemic listeriosis. Depressed resistance expressed immediately after tumor implantation was traced to inadvertent association of tumor with lactic dehydrogenase virus. Tumor cured of virus was totally inactive.
Immunity to herpes simplex virus type 2: cell-mediated immunity in latently infected guinea pigs
Authors: Donnenberg A D , Chaikof E , Aurelian L
Published: January 2020

Cell-mediated (CMI) and humoral immunity to herpes simplex virus type 2 (HSV-2) were evaluated in infected strain 13/N guinea pigs with (45%) and without a history of recurrent herpetic disease. Virus was isolated by cocultivation from active herpetic lesions (9 of 10) as well as from the footpads (17 of 38), sacral ganglia (7 of 21), and sciatic nerves (1 of 21) of asymptomatic animals. Viral isolates grew in cells of human origin and were neutralized by hyperimmune anti HSV-2 sera. Humoral immunity measured by the presence of virus-neutralizing antibody was similar in both experimental groups. The involvement of CMI in recurrent disease was assessed by comparing lymphocyte transformation (LT) and leukocyte migration inhibition factor (LIF) responses in animals with a history of recurrent disease studied while asymptomatic (quiescent) and in animals without clinical evidence of recurrent disease (seropositive controls). Spleen cells from quiescent animals evidenced significant impairment of both LIF and LT responses as reflected in the requirement of higher antigen concentrations (up to 58-fold) and longer in vitro culture periods (up to 2.5 days) to mount responses comparable in magnitude to those observed in the seropositive control groups. Peripheral blood lymphocyte cultures obtained from quiescent animals showed similar impairment of LIF responses but displayed intact LT response. The data suggest that recurrent disease is associated with an impairment in the generation of anamnestic effector functions as reflected by altered kinetics and dose response patterns in in vitro secondary responses.
Increased susceptibility to herpes simplex virus infections in children with acute measles
Authors: Orren A , Kipps A , Moodie J W , Beatty D W , Dowdle E B , McIntyre J P
Published: January 2020

Children with measles treated either in hospital or as outpatients were examined for clinical or laboratory evidence of oropharyngeal herpes simplex virus (HSV) infection. HSV was isolated from 43% of the hospitalized children and 37% of the outpatient children and an additional 9% of the hospitalized group had lesions without the virus being isolated. The incidence of both HSV isolation and clinical lesions in infected children was significantly greater in children hospitalized for measles than in a control group of children hospitalized for tuberculosis. Data from the outpatient group strongly suggest that malnourished children with measles are particularly susceptible to HSV infection. The immunosuppressed state of the children with acute measles was demonstrated by impaired lymphocyte transformation responses to phytohemagglutinin and the inability of their serum to support normal transformation responses by lymphocytes from normal individuals. However the extent of this immunosuppression was unrelated to the susceptibility of the children to HSV infection.
Mitogenic response of C3H/HeJ mouse lymphocytes to polyanionic polysaccharides obtained from Bordetella pertussis endotoxin and from other bacterial species
Authors: Girard R , Chaby R , Bordenave G
Published: January 2020

Lipopolysaccharide extracted from Bordetella pertussis was mitogenic for spleen cells of endotoxin-resistant C3H/HeJ mice. Although endotoxic lipid A was inactive, mitogenic activity of lipopolysaccharide was exhibited by purified preparations of polysaccharides I and II, which constitute the carbohydrate moiety of the macromolecule. These low-molecular-weight (2,800 and 3,600) polysaccharides, containing carboxyl groups, were not mitogenic for thymocytes and splenic T-cells of C3H/HeJ mice, but did show mitogenic activity for splenic B-cells of C3H/HeJ mice and for spleen cells of C57BL/6 athymic nude mice. The mitogenic activities of polysaccharides I and II were also compared with those of other polyanionic polysaccharides, and the results indicate that high molecular weight is not necessary, and negative charges are not sufficient, for mitogenicity.
Nature of the cross-protective antigen in subcellular vaccines of Streptococcus pneumoniae
Authors: Au C C , Eisenstein T K
Published: January 2020

Studies have been carried out to investigate the nature of the antigen present in subcellular extracts of a rough strain of Streptococcus pneumoniae A662b which has been shown to confer protection in mice against challenge with smooth, virulent organisms of the homologous and heterologous serotypes. The finding that whole, heat-killed cells were also capable of immunizing mice against challenge with organisms of heterologous serotypes suggests that the immunogen is present on the surface of the rough pneumococcal cell. Ribosomes purified by sucrose gradient centrifugation were not protective, but material recovered in the pellet retained activity. Subcellular extracts prepared from spheroplasts with a partial absence of cell wall showed decreased protective capacity, and extracts prepared from wall-deficient protoplasts were not protective. Crude cell walls evidenced cross-serotype protection, but purified walls did not protect. These results are interpreted as suggesting that the active moiety in the subcellular vaccine is present on the surface of rough pneumococci and is either a wall antigen that must be part of a larger macromolecular complex to be immunogenic, or a substance associated with the cell wall that is present in crude, but not purified, cell wall fractions.
Evaluation of the role of the pneumococcal Forssman antigen (F-polysaccharide) in the cross-serotype protection induced by pneumococcal subcellular preparations
Authors: Au C C , Einsenstein T K
Published: January 2020

We tested the hypothesis that the capacity of subcellular preparations of rough pneumococci to give cross-serotype protection is due to the presence of the pneumococcal Forssman antigen (F-polysaccharide). We found by hemagglutination inhibition that the Forssman antigen is present in the subcellular extracts. However, we concluded that the Forssman antigen is not the protective immunogen in the pneumococcal subcellular preparation, since absorption with sheep erythrocytes failed to remove the protective capacity from antiserum raised against the vaccine. Other evidence mitigating against the pneumococcal Forssman antigen being the protective immunogen included the absence of a detectable hemolytic titer in protective antiserum raised against the subcellular preparation, the failure of high-titered sheep hemolysin to passively protect mice against pneumococcal infection, and the failure of purified F-polysaccharide to immunize mice against pneumococcal infection.
Influence of the bursa of Fabricius on the pathogenesis of Marek's disease
Authors: Schat K A , Calnek B W , Fabricant J
Published: January 2020

A series of experiments was conducted to study the influence of embryonal bursectomy (EBX) on the early and late pathogenesis of Marek's disease (MD). The early lytic infection in the lymphoid organs normally associated with oncogenic MD virus infection in intact chickens was not seen in EBX chickens. Therefore, the damage to the immune system was minimal. EBX chickens also had lower viremia levels, higher lymphocyte responses to mitogens, and a lower or delayed MD mortality when compared with intact chickens. Furthermore, it was shown that although vaccination with SB-1 by itself did not protect against a highly virulent MD transplantable tumor, the combination of EBX and vaccination gave significant protection. All these effects could be explained by an enhanced immune response in EBX birds. In contrast, the pathogenesis of nononcogenic MD virus was not influenced by EBX. The possible mechanism(s) involved in these observed effects of EBX on MD pathogenesis are discussed.
Endogenous pyrogen production by human blood monocytes stimulated by staphylococcal cell wall components
Authors: Oken M M , Peterson P K , Wilkinson B J
Published: January 2020

To determine the properties of Staphylococcus aureus contributing to its pyrogenicity, we compared, in human monocytes, endogenous pyrogen production stimulated by heat-killed S. aureus with that stimulated by purified S. aureus cell walls or by particulate peptidoglycan prepared from the same strain. Peptidoglycan, but not the purified cell wall preparation, was found comparable to S. aureus as an endogenous pyrogen stimulus. This finding was associated with a more effective monocyte phagocytosis of S. aureus and peptidoglycan as compared with that of purified cell walls. Lysostaphin digestion of peptidoglycan markedly reduced its pyrogenicity. To test whether the chemical composition of the ingested particles is important, latex particles were tested as possible stimuli for monocyte endogenous pyrogen release. Although 40 to 68% of monocytes ingested latex particles during the first hour, there was no evidence of endogenous pyrogen activity in the supernatant even when supernatants equivalent to 5.2 X 10(6) monocytes were tested. This study demonstrates that the pyrogenic moiety of the S. aureus cell wall resides in the peptidoglycan component. Phagocytosis is not in itself a pyrogenic stimulus, but rather serves as an effective mechanism to bring about contact between the chemical stimulus and the monocyte.
Eikenella corrodens adherence to human buccal epithelial cells
Authors: Yamazaki Y , Ebisu S , Okada H
Published: January 2020

The mechanism of Eikenella corrodens adherence to human buccal epithelial cells in vitro was studied. Initial experiments to determine the optimal conditions for adherence of E. corrodens to buccal epithelial cells showed that adherence was dependent on time, temperature, bacterial concentration, and pH. Different strains of E. corrodens varied in their ability to adhere, and strain 1073 showed the greatest ability in adherence. Strain 1073 was selected for studies of adherence mechanisms. Trypsin treatment or heating (100 degrees C, 10 min) of the bacterial cells abolished their capacity to adhere to buccal epithelial cells. Treatment of buccal epithelial cells with trypsin also abolished adherence of E. corrodens 1073, whereas neuraminidase treatment of buccal epithelial cells enhanced the adherence. The adherence was inhibited by ethylenediaminetetraacetic acid and restored by adding Ca2+. The adherence was remarkably inhibited by sugars containing D-galactose and n-acetyl-D-galactosamine. Treatment of neuraminidase-treated epithelial cells with sodium metaperiodate or alpha- and beta-galactosidase did not decrease the adherence. These data suggest that adherence of E. corrodens 1073 to human buccal epithelial cells may require the interaction of lectin-like proteins on the bacterial surface with galactose-like receptors on the surface of epithelial cells.
Differences in the Adsorptive Behavior of Human Strains of
Actinomyces viscosus
and
Actinomyces naeslundii
to Saliva-Treated Hydroxyapatite Surfaces
Authors: Qureshi J. V. , Gibbons R. J.
Published: January 2020

Human strains of
Actinomyces viscosus
and
A. naeslundii
differ in the time of their appearance and in their patterns of colonization in the mouth. Strains of these organisms were found to differ in their abilities to adsorb to saliva-treated hydroxyapatite (S-HA) surfaces, thought to mimic the teeth, and these differences parallel their patterns of colonizing the dentition. Thus, strains of
A. viscosus
tended to adsorb in higher numbers to hydroxyapatite (HA) treated with saliva of older children and adults than with saliva of younger children (ages 6 to 11). These salivary changes may account for the increased frequency with which this organism can be isolated from the mouths of children as they grow older. In contrast, strains of
A. naeslundii
and
Streptococcus mutans
did not show a preference for attaching to either type of S-HA. Strains of
A. viscosus
also generally adsorbed in higher numbers than
A. naeslundii
to HA treated with adult saliva; this may explain why higher proportions of
A. viscosus
are usually recoverable from the teeth of adults, even though
A. naeslundii
is generally present in higher proportions in saliva. Significant variation was noted between strains and between saliva samples collected from different donors. The differences in adsorptive behavior of strains of these species suggests that they are binding to different receptors in the salivary glycoprotein coating on HA surfaces. Adsorption of
A. naeslundii
ATCC 12104 was enhanced when S-HA was pretreated with neuraminidase, but this had little effect upon the adsorption of other
Actinomyces
strains tested. Adsorption of strain ATCC 12104 to S-HA was also strongly inhibited by fructose and sucrose and weakly inhibited by glucose, maltose, galactose, and lactose. However, other strains of
A. naeslundii
tested were affected less, or not at all, by these sugars. Adsorption of two strains of
A. viscosus
was not affected by any of the sugars or amines tested.
Interactions between Rickettsia prowazekii and rabbit polymorphonuclear leukocytes: rickettsiacidal and leukotoxic activities
Authors: Walker T S , Winkler H H
Published: January 2020

Rickettsia prowazekii was assessed for in vitro susceptibility to phagocytosis by rabbit polymorphonuclear leukocytes. [alpha-32P]adenosine triphosphate-labeled rickettsiae were used to determine phagocytosis and adsorption quantitatively. R. prowazekii was less susceptible to phagocytosis than were Escherichia coli and Neisseria gonorrhoeae. Although R. prowazekii was similar to E. coli in susceptibility to superoxide and activated halide, few phagocytized rickettsial cells were inactivated after being ingested by polymorphonuclear leukocytes, and rickettsiae were observed free in polymorphonuclear leukocyte cytoplasm. At low ratios of rickettsiae to polymorphonuclear leukocytes, PMN phagocytosis increased as a linear function of time, but at high ratios (multiplicity of infection, 50) rickettsiae were phagocytized during only the first 10 min of incubation. Polymorphonuclear leukocytes were damaged in the presence of high rickettsial multiplicities such that they released lactate dehydrogenase into the medium and lost the ability to phagocytize both rickettsiae and E. coli. The amount of leukotoxic activity in a given rickettsial sample correlated with the relative hemolytic activity of that sample. The rickettsial leukotoxin was probably not a soluble product, was active in the absence of phagocytosis, and was inhibited by inactivation of the rickettsiae or by incubation at 4 degrees C.
Hemagglutination of Human Type O Erythrocytes, Hemolysin Production, and Serogrouping of
Escherichia coli
Isolates from Patients with Acute Pyelonephritis, Cystitis, and Asymptomatic Bacteriuria
Authors: Green Cheryl P. , Thomas Virginia L.
Published: January 2020

The purpose of this investigation was to study potential virulence factors associated with
Escherichia coli
urinary pathogens isolated from patients with urinary tract infection. These factors were compared with characteristics of normal-flora
E. coli
isolated from stool specimens of healthy individuals without a history of urinary tract infection. The potential virulence factor focused on in this study was hemagglutination (HA) of human type O erythrocytes by
E. coli
urinary pathogens. A total of 265 strains of
E. coli
isolated from patients with urinary tract infections were tested for their ability to hemagglutinate human type O erythrocytes; of these, 148 (56%) were HA positive. Only 6 of 36 fecal
E. coli
strains (17%) isolated from healthy controls were HA positive. This significant association of the presence of hemagglutinin on
E. coli
that causes urinary tract infections indicates the likelihood that HA is a marker of virulence. Only 12% (5 of 43) of
Proteus mirabilis
and 3% (3 of 104) of
Klebsiella pneumoniae
urinary isolates were HA positive. There was a trend for HA-positive
E. coli
to be isolated from patients with kidney infections and positive tests for antibody-coated bacteria rather than bladder infections and negative tests for antibody-coated bacteria, although the difference was not statistically significant. There was a significant correlation (
P
< 0.025) between hemolysin production and HA; 67% (69 of 103) of the isolates that produced hemolysin also hemagglutinated human type O erythrocytes. There was no significant correlation between HA and motility, although there was a trend for flagellated organisms to be non-hemagglutinators. There was a marked correlation between the presence of hemagglutinin and the serogroup of the
E. coli
isolate; serogroups O4, O7, and O50 were almost always HA positive (57 of 63; 90%). In contrast, serogroups O8 and O25 were rarely HA positive (2 of 30; 7%).
Effect of pH and human saliva on protease production by Candida albicans
Authors: Germaine G R , Tellefson L M
Published: January 2020

The elaboration of extracellular proteolytic activity by Candida albicans during growth in laboratory broth or in human whole salivary supernatant was investigated. Growth of the organism in broth at pH 3 to 7 followed by assay of culture supernatants at pH 4 (optimum for activity) indicated protease was only present in cultures grown at a pH of less than 5. In contrast, growth in sterile human whole salivary supernatant over the pH range of 3 to 7 uniformly failed to result in production of protease. Growth of the organism at pH 4 in broth supplemented with saliva resulted in a saliva-dependent inhibition of protease production. Although the addition of up to 16% (vol/vol) saliva had essentially no effect on growth, 4% saliva caused a 50% reduction in proteolysis of substrate protein. Due to the low pH requirement for protease production and activity and the demonstration that saliva is a potent inhibitor of protease synthesis, we conclude C. albicans most likely does not produce extracellular protease in the human oral cavity.
Propagation of Korean hemorrhagic fever virus in laboratory rats
Authors: Lee P W , Amyx H L , Gibbs C J , Gajdusek D C , Lee H W
Published: January 2020

Korean hemorrhagic fever virus (KHFV) has been adapted to the Wistar and Fisher strains of rats. Infection was detected by the appearance of specific antigen in the lung tissue of the infected rats at 14 to 64 days after inoculation and by the appearance of circulating antibodies in ther serum which reacted specifically with KHFV antigen in the lungs of infected Apodemus agrarius subsp. coreae 3 weeks after inoculation. Distribution of antigen in rat tissues as determined by immunofluorescent staining was the same as that in Apodemus mice except that antigen was present in the spleens of rats. Adaptation of KHFV to the laboratory rat provides an animal model that is free of wild rodent viruses and is readily available for use in studies on the characterization of KHFV.
Use of combined immunization routes in induction of a salivary immunoglobulin A response to Streptococcus mutans in Macaca fascicularis monkeys
Authors: Linzer R , Evans R T , Emmings F G , Genco R J
Published: January 2020

Various combinations of immunization routes were examined for ability to elicit or prolong (or both) a salivary secretory immunoglobulin A response to Streptococcus mutans strain Ingbritt (serotype c) in Macaca fascicularis monkeys. Intraductal (i.d.), per os (p.o.), and subcutaneous (s.c.) routes were utilized. Four groups of three to five monkeys each were immunized by the following schedules: group I--p.o., s.c., i.d.; group II--i.d., p.o., i.d.; group III--s.c., p.o., i.d.; and group IV--control. Immune responses in the serum and parotid fluid were quantitated by using passive hemagglutination assays with purified serotype-specific polysaccharide and by indirect immunofluorescent staining assays. Both s.c. and i.d., but not p.o., routes resulted in detectable serum antibody responses. Only i.d. immunization resulted in a measurable salivary response. Indirect immunofluorescent staining revealed specific secretory immunoglobulin A antibodies in the parotid fluid which correlated with passive hemagglutination titers. The p.o. procedures used in this study did not result either in a prolonged immune response or in measurable tolerance related to the humoral or secretory immune system.
Effect of fructose and other carbohydrates on the surface properties, lipoteichoic acid production, and extracellular proteins of Streptococcus mutans Ingbritt grown in continuous culture
Authors: Hardy L , Jacques N A , Forester H , Campbell L K , Knox K W , Wicken A J
Published: January 2020

Streptococcus mutans Ingbritt was grown in a chemostat at destined dilution rates in either 0.5% fructose or 0.5% sorbitol and at destined pH values in 0.5% fructose. The yield of cells was affected by the carbohydrate source, as well as by the pH, with the lowest yield being at pH 5.5 in 0.5% fructose. Fructose-grown cells showed greater susceptibility to lysis by a muramidase than the corresponding glucose-grown cells, but there were no marked differences in the lytic susceptibilities of the corresponding cell wall preparations or in the serological reactivities of wall lysates with antiserum to S. mutans Ingbritt. The greatest amounts of cellular lipoteichoic acid were obtained at high dilution rates in both fructose and sorbitol, as well as at high pH values in fructose. The greatest amounts of extracellular lipoteichoic acid were found at low dilution rates, as estimated by rocket immunoelectrophoresis and also by hemagglutination. Three major extracellular protein components were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the effects of growth conditions on these components were determined. Results for batch-grown cultures showed that there was genotypic variation in the susceptibility of cells to lysis by a muramidase. The enhancement of lipoteichoic acid production by fructose and sorbitol in batch cultures was not identical in representative strains of S. mutans serotype c, nor was the effect of fructose found uniformly in representative strains of the different S. mutans serotypes.
Bactericidal activity of fractionated granule contents from human polymorphonuclear leukocytes: role of bacterial membrane lipid
Authors: Modrzakowski M C , Paranavitana C M
Published: January 2020

Granule contents from human polymorphonuclear leukocytes were prepared by extraction with 0.2 M acetate, pH 4. A buffer extract fraction (peak D) obtained by Sephadex G-100 column chromatography demonstrated distinct antimicrobial activity toward Acinetobacte sp. independent of added H2O2 or Cl-. The protein of this fraction had an apparent molecular weight of 9,000 and demonstrated time and dose dependence that was more active against stationary-growth cells than mid-log-phase cells. The bactericidal activity of the fraction was most active at 37 degrees C, with only slight activity demonstrated at 22 degrees C and no activity at 4 degrees C. Boiling the granule fraction for 30 min did not affect the antimicrobial activity. However, pronase or trypsin pretreatment of the peak D fraction reduced its antimicrobial activity. When the membrane lipid composition of Acinetobacter sp. was altered by growth on specific n-alkane carbon sources, the susceptibility to the granule fraction was also altered. Resistance to the activity of the granule fraction increased as the carbon chain length of the growth substrate increased. Liposomes formed from Acinetobacter sp. lipid extracts and containing glucose were made leaky with the addition of the granule fraction (boiled and not boiled), suggesting a membrane-disruptive activity of the granule protein against Acinetobacter sp. membranes.
Analysis of avian leukosis virus infections with an enzyme immunoassay
Authors: Clark D P , Ball R F , Dougherty R M
Published: January 2020

An enzyme-linked immunosorbent assay (ELISA) for avian leukosis virus group-specific antigen was used to study infections with and shedding of avian leukosis virus in a commercial flock of chickens with a known high incidence of infection. Avian leukosis virus group-specific antigen was detected in serum or cloacal washings from 76% of a group of 100 61-week-old hens. With eggs collected during the next 3 weeks, antigen was detected in the albumen of 88% of the eggs from ELISA-positive hens and 2% of the eggs from ELISA-negative hens. Results of assays for infectivity correlated closely with the ELISA results. Serum and cloacal specimens were almost equally sensitive in detecting infection; however, a higher proportion of cloaca-positive hens (97%) than serum-positive hens (91%) shed virus in their eggs. Similar results were obtained from a second sampling of eggs taken when the hens were 84 weeks old, after an intervening molt. Avian leukosis virus infection was correlated with reduced egg production and increased mortality. Eggs were produced by 100% of the ELISA-negative birds during both sampling periods, whereas only 69% of the ELISA-positive birds produced eggs at 61 weeks and 76% produced eggs at 84 weeks. All birds that were ELISA negative at 61 weeks survived the experiment. Of 14 ELISA-positive birds that died and were examined postmortem between 61 and 84 weeks, 8 had malignancies, and the remainder died of a variety of nonmalignant diseases.
Influence of yeast mannan on human neutrophil functions: inhibition of release of myeloperoxidase related to carbohydrate-binding property of the enzyme
Authors: Wright C D , Herron M J , Gray G R , Holmes B , Nelson R D
Published: January 2020

We investigated the possibility that dissolved mannan polysaccharide from Candida may have an inhibitory influence on the host defense mechanisms associated with neutrophils and thereby contribute to the pathogenesis of candidoses. We created a model for this hypothesis by using mannan derived from bakers' yeast (Saccharomyces cerevisiae) and mannan isolated from the serum of a patient with chronic mucocutaneous candidosis. We observed that these mannans inhibited the respiratory burst and release of myeloperoxidase stimulated by phagocytosis of serum-opsonized zymosan in vitro. Mannan did not inhibit release of three other lysosomal enzymes. The selective inhibition of release of myeloperoxidase was attributable to a carbohydrate-binding property of the enzyme, with the mannan causing co-sedimentation of the enzyme with the cellular fraction.
Biochemistry of Theiler's murine encephalomyelitis virus isolated from acutely infected mouse brain: identification of a previously unreported polypeptide
Authors: Stroop W G , Baringer J R
Published: January 2020

The WW strain of Theiler's murine encephalomyelitis virus (WW-TMEV) was purified from homogenates of acutely infected mouse brain. Infectious WW-TMEV was found to have an estimated sedimentation coefficient of 156 (s20,w) and a density of 1.35 g/cm3 in CsCl. Electron microscopy revealed a homogeneous population of 26-nm nonenveloped particles. Iodination of sodium dodecyl sulfate (SDS)-disrupted virions revealed four major capsid proteins with molecular weights of 58,000, 37,000, 34,000, and 27,000. A 6,000-dalton polypeptide was observed after long exposures of autoradiograms. The 37,000-, 24,000-, 27,000-, and 6,000-dalton polypeptides corresponded to picornaviral VP1, VP2, VP3, and VP4 capsid polypeptides, respectively. Comparison of autoradiograms of virions radiolabeled before and after SDS disruption indicated that the 58,000-dalton protein, VP2, and VP3 preferentially bound 125I under the labeling conditions used. Direct evidence was obtained that VP2 and VP3 were derived from the 58,000-dalton polypeptide by isolation of the 58,000-dalton polypeptide from polyacrylamide gels run under nonreducing conditions and subjecting it to reelectrophoresis under reducing conditions. The effect of trypsin on purified virions and their polypeptides was also investigated. Trypsin-sensitive sites were found in the 58,000-dalton protein, VP1, and VP2. Our results indicate that, in addition to the four typical picornaviral capsid polypeptides, there is a 58,000-dalton polypeptide present in WW-TMEV, which is sensitive to trypsin and can be reduced into two of the capsid proteins, VP2 and VP3.
Immune Defenses Against
Legionella pneumophila
in Rats
Authors: Rolstad Bent , Berdal Bjørn P.
Published: January 2020

Rats were examined for their susceptibility to infection with
Legionella pneumophila.
Different strains of
L. pneumophila
representing serogroups 1 to 4 were tested (Philadelphia 1 and 2, Togus 1, Bloomington 2, Los Angeles 1, and the recently isolated LD-8 from the epidemics in Västeraas, Sweden). When about 9 × 10
8
bacteria, or 6 × 10
8
colony-forming units, were injected intraperitoneally, only rats infected with the LD-8 strain showed signs of illness. They became ill within 4 to 6 h and usually died within 24 h with septicemia and signs of circulatory collapse. Bacteria killed by heating at 100°C for 15 min lost their pathogenicity. Rats that were preimmunized with the Philadelphia 1 strain (same serogroup as LD-8), regardless of the route of immunization (subcutaneous, intraperitoneal, or intravenous), developed resistance to subsequent infection with LD-8. This resistance was serogroup specific and could be passively transferred to nonimmune animals with syngeneic immune serum or immunoglobulin fractions of serum. Antiserum or gamma globulin-enriched serum fractions from sheep with specificity for the Philadelphia 1 or Togus 1 strains also protected rats from the lethal effect of strain LD-8. The kinetics of the antibody and blood leukocyte response to immunization with the Philadelphia 1 strain of
L. pneumophila
in normal rats was investigated. During week 1 after intravenous injection the rats developed a marked lymphocytosis, which lasted for at least 1 week. The antibody response, as measured by indirect immunofluorescence or by a modification of the microagglutination method which we describe here, reached a peak during week 2 after immunization. Splenectomized rats were also resistant to infection with the Philadelphia 1 strain, but their antibody responses were substantially lower than those of their sham-operated littermates.
Placental and fetal alterations due to Venezuelan equine encephalitis virus in rats
Authors: García-Tamayo J , Esparza J , Martínez A J
Published: January 2020

Histopathological changes in the placentas, embryos, and fetuses of rats inoculated intraperitoneally with the virulent Guajira strain of Venezuelan equine encephalitis virus were studied by light microscopy and immunoperoxidase methods. Rats inoculated before day 15 of pregnancy showed necrosis and hemorrhages in the embryonic disks. Swelling of cytoplasm and nuclear pyknosis of cyto- and syncytotrophoblastic cells were noted as early as 2 days after inoculation. During weeks 1 and 2 of pregnancy, death of the embryos was always observed 3 to 4 days after Venezuelan equine encephalitis virus inoculation. Placental and fetal damage varied among the specimens. In rats 18 days pregnant and sacrificed 2 days after inoculation, there were some viable fetuses; the placentas showed inflammatory reactions in the mesometrial and decidual vessels. Other rats sacrificed at 3 to 4 days after inoculation showed large placental infarcts with fetal death. Viremia peaked during day 2 after inoculation. Immunoperoxidase stains demonstrated viral antigens present in the decidua, myometrium, and cyto- and syncytotrophoblastic cells. These experiments provide additional data regarding the pathogenesis and structural damage in the placental and fetal tissues caused by Venezuelan equine encephalitis virus.
Localization of Streptococcus mutans GS-5 glucosyltransferases and intracellular invertase
Authors: Bozzola J J , Kuramitsu H K , Maynard M T
Published: January 2020

Antibodies directed against Streptococcus mutans GS-5 intracellular invertase and glucosyltransferase fractions capable of synthesizing primarily water-soluble or insoluble glucans were used to ultrastructurally localize the enzymes by means of the unlabeled antibody peroxidase-antiperoxidase method. This immunocytochemical procedure revealed that the intracellular invertase was associated primarily with the cytoplasmic membrane of the cariogenic organism. The glucosyltransferase complex responsible for insoluble glucan synthesis was localized as aggregates attached to the cell surface or extracellular polysaccharides of strain GS-5. In contrast, the glucosyltransferase activity synthesizing primarily water-soluble glucans was distributed uniformly over the cell surface or in association with extracellular polysaccharides. These results are discussed relative to the sucrose-metabolizing ability of Streptococcus mutans.
Helical Conformation of
Treponema pallidum
(Nichols Strain),
Treponema paraluis-cuniculi, Treponema denticola, Borrelia turicatae
, and Unidentified Oral Spirochetes
Authors: Stepan Daniel E. , Johnson Russell C.
Published: January 2020

Borrelia turicatae
(mouse virulent) and
Treponema denticola
, a small oral treponeme, formed right-handed helices as determined by scanning electron microscopy.
Treponema pallidum
(Nichols strain),
Treponema paraluis-cuniculi
, and two unidentified oral spirochetes displayed left-handed helices.
Incorporation of [
14
C]Methionine by
Yersinia enterocolitica
After Invasion of HeLa Cells
Authors: McCoubrey William K. , Howard Lawrence V.
Published: January 2020

Invasion of HeLa cells by
Yersinia enterocolitica
can be measured by the incorporation of [
14
C]methionine in the presence of streptomycin and cycloheximide.
Specific
Pseudomonas
Immunoglobulin E Antibodies in Sera of Patients with Cystic Fibrosis
Authors: Shen Jasmin , Brackett Robert , Fischer Thomas , Holder Alan , Kellogg Frank , Michael J. Gabriel
Published: January 2020

Immunoglobulin E antibodies to
Psuedomonas aeruginosa
were demonstrated in patients with cystic fibrosis colonized with the bacterium.
Identification of immunogenic outer membrane proteins of Haemophilus influenzae type b in the infant rat model system
Authors: Hansen E J , Frisch C F , McDade R L , Johnston K H
Published: January 2020

Outer membrane proteins of Haemophilus influenzae type b which are immunogenic in infant rats were identified by a radioimmunoprecipitation method. Intact cells of H. influenzae type b were radioiodinated by a lactoperoxidase-catalyzed procedure, and an outer membrane-containing fraction was prepared from these cells. These radioiodinated outer membranes were mixed with sera obtained from rats convalescing from systemic H. influenzae type b disease induced at 6 days of age, and the resultant (antibody-outer membrane protein antigen) complexes were extracted from these membranes by treatment with nonionic detergent and ethylenediaminetetraacetic acid. These soluble antibody-antigen complexes were isolated by means of adsorption to protein A-bearing staphylococci, and the radioiodinated protein antigens were identified by gel electrophoresis followed by autoradiography. Infant rats were shown to mount a readily detectable antibody response to several different proteins present in the outer membrane of H. influenzae type b. Individual infant rats were found to vary both qualitatively and quantitatively in their immune response to these immunogenic outer membrane proteins.
Transposon-facilitated recombination in classical biotypes of Vibrio cholerae
Authors: Sublett R D , Romig W R
Published: January 2020

Transposon-facilitated recombination (Tfr) donors of classical Vibrio cholerae strain 162 were constructed by introducing the ampicillin transposon Tn1 into the P conjugative plasmid and the bacterial chromosome. The improved donors mediated high-frequency, polarized transfer of chromosomal genes from origins to confirm the gene orders of the previous classical strain 162 genetic map and to establish its circularity. Significant transfer of linked genes from E1 Tor Tfr donors to classical recipients was demonstrated, and other evidence for genetic relatedness of these two V. cholerae biotypes is discussed.
Edema and hemoconcentration in mice experimentally infected with Vibrio vulnificus
Authors: Bowdre J H , Poole M D , Oliver J D
Published: January 2020

Vibrio vulnificus (lactose-positive Vibrio), a recently recognized pathogenic marine species, produced extreme hemoconcentration and death within 3 to 6 h after subcutaneous or intraperitoneal injection of 10(8) viable cells into mice; hemotocrit values approached 70% (normal, 45%). About 1 ml of edema fluid accumulated at the site of each subcutaneous injection, and locally increased vascular permeability was demonstrated by a skin bluing assay, using Evans blue dye. A corresponding fluid accumulation did not occur in the peritoneal cavity after an intraperitoneal injection. Filter-sterilized supernatants of cultures grown under a variety of conditions did not produce local edema or lethality, nor did whole Vibrio cells killed by a variety of methods or disrupted by sonic oscillation. Edema fluids collected from infected mice and sterilized by filtration had no effect when they were injected subcutaneously or intraperitoneally into mice. Inocula of 10(9) viable cells of V. vulnificus contained within a diffusion chamber implanted subcutaneously did not produce skin bluing, edema, or lethality; Vibrio cells remained viable and virulent within these chambers for at least 2 weeks. These experiments suggested that vascular permeability changes in V. vulnificus infections may not be attributable to a diffusible toxin and may require direct contact between host cells and viable Vibrio cells.
Measurement of 5′-Nucleotidase in Mouse Peritoneal Macrophages in Listeriosis
Authors: Pietrangeli C. E. , Skamene E. , Edelson P. J. , Kongshavn P. A. L.
Published: January 2020

5′-Nucleotidase activity in peritoneal macrophages of mice was measured both before and after infection with
Listeria monocytogenes
in hosts which possessed high or low anti-listerial resistance either due to a genetically determined trait or as a result of splenectomy. Reduction in enzyme activity was directly related to the degree of infection that developed in the hosts and hence was inversely related to the level of anti-listerial resistance observed. Basal 5′-nucleotidase activity was significantly lower in noninfected hosts that possessed high anti-listerial resistance, possibly reflecting a higher level of native macrophage activation in these hosts.
Serotypes of attachment pili of enterotoxigenic Escherichia coli isolated from humans
Authors: Deneke C F , Thorne G M , Gorbach S L
Published: January 2020

Pili from enterotoxigenic Escherichia coli isolated from humans have been partially purified, and antisera have been prepared. These pili were initially attached to erythrocytes and then removed by thermal elution for purification. Three distinct antigenic types of pili have been identified. Antisera against these three pili types reacted with 60 of 106 (56%) enterotoxigenic E. coli isolated from humans but not with nontoxigenic, normal human fecal isolates of E. coli nor with enterotoxigenic E. coli strains isolated from animals. There was no correlation between pili serogroup and any of the following toxin production (heat labile, heat stable, or both), O antigenic type, geographical source of isolation, or mannose-resistant hemagglutination patterns of various erythrocyte types.
Rubella-Associated Arthritis: Rescue of Rubella Virus from Peripheral Blood Lymphocytes Two Years Postvaccination
Authors: Chantler J. K. , Ford D. K. , Tingle A. J.
Published: January 2020

Rubella virus was isolated from the peripheral lymphocytes of a patient with rubella-associated arthritis 2 years after rubella vaccination. The rescue of the virus was carried out by stimulating the lymphocytes with mitogens for several days in cultures and then cocultivating them with RK13 cells at 35°C. Rubella virus was detected by a variety of techniques, including electron microscopy, indirect immunofluorescence, polyacrylamide gel analysis of labeled viral proteins, and microfocus assay for infectious virus particles. Assessment of the immune status of the patient did not indicate any impairment of immune function associated with long-term persistence of the virus.
Host-parasite interaction and development of infraforms in chicken embryos infected with Coxiella burnetii via the yolk sac
Authors: Khavkin T , Sukhinin V , Amosenkova N
Published: January 2020

Two phase I strains of Coxiella burnetii of different virulence were injected into the yolk sacs of chicken embryos, and the yolk sacs and livers were examined at intervals by light, fluorescent, and electron microscopy. The high absorptive and digestive capacities of the yolk endoderm contributed to he entrance of the organisms into endodermal epithelial cells where C. burnetii multiplied. Organisms multiplied not only inside specific vacuoles originating from phagolysosomes but also in the cytoplasm itself. Lysis of the limiting membrane of some phagolysosomes, a normal function of endodermal cells, as well as rupture of vacuoles, provided the release of C. burnetii into the cytoplasm. The C. burnetii strain of greater virulence infected 100% of the endodermal cells, whereas the strain of lesser virulence infected only 60%. Budding of very small particles from the C. burnetii bodies was demonstrated. The particles were regarded as filterable forms of the organism. Despite the enormous multiplication of C. burnetii in the endodermal cells, organisms were only rarely detected in the vitelline blood vessels and liver sinusoids of the embryos. Peculiarities of the infectious process of C. burnetii in chicken embryos and possible mechanisms of limitation of spread of the infection are discussed.
Genetic Transformation of
Streptococcus mutans
Authors: Perry Dennis , Kuramitsu Howard K.
Published: January 2020

Three strains of
Streptococcus mutans
belonging to serotypes a, c, and f were transformed to streptomycin resistance by deoxyribonucleic acids derived from homologous and heterologous streptomycin-resistant strains of
S. mutans
and
Streptococcus sanguis
strain Challis. Homologous transformation of
S. mutans
was less efficient than heterologous transformation by deoxyribonucleic acids from other strains of
S. mutans.
Role of macrophages in resistance of mice to experimental cryptococcosis
Authors: Monga D P
Published: January 2020

Mice with either a stimulated or depressed reticuloendothelial system were used to study the role of macrophages in resistance to experimental Cryptococcus neoformans infection. Silica, administered intravenously to destroy macrophages, considerably decreased the phagocytic index of the reticuloendothelial system as determined by a carbon clearance test. Silica given 1 day before intravenous challenge with 5 X 10(3) (1 50% lethal dose) of C. neoformans markedly decreased the resistance of mice to cryptococcal infection. Mice given repeated doses of BCG to nonspecifically activate their macrophages could withstand a challenge of 100 50% lethal doses of C. neoformans. These results provide evidence that macrophages play an essential role in natural or nonspecific cell-mediated immunity to murine cryptococcosis.
Reduction of circulating granulocytes induced by type 1 pneumococcal cell walls in New Zealand white rabbits
Authors: Goldblum S E , Reed W P , Barton L L
Published: January 2020

Granulocytopenia seen during human pneumococcal disease is associated with a worsened prognosis. Streptococcus pneumoniae type 1 reduces circulating granulocytes and induces pulmonary leukostasis in rabbits. We studied which type 1 pneumococcal fraction(s) might be responsible for the reduction in circulating granulocytes. Rabbits were challenged intravenously with nonpyrogenic sterile saline, sonicated type 1 pneumococci, capsular polysaccharide from type 1 pneumococci, or cell walls from type 1 pneumococci. Nonviable pneumococci caused a mean decrease in blood granulocytes of 64% as compared with a mean increase of 124% in saline-injected controls, a difference significant at P less than 0.001. Pneumococcal cell walls induced significant decreases in circulating granulocytes at all doses tested when compared with saline-injected controls, whereas capsular polysaccharide induced no reduction in granulocytes. On a weight-for-weight basis, cell wall induced significantly more granulocyte reduction than did capsular polysaccharide at doses of either 10 mg (P less than 0.01) or 20 mg (P less than 0.005). A nonencapsulated pneumococcus also induced a profound granulocyte reduction (mean decrease in blood granulocytes, 88%) in the absence of detectable circulating polysaccharide. The cell wall fraction of S. pneumoniae type 1 was a more effective constituent in promoting the reduction in circulating granulocytes in rabbits.
Variation in human rotavirus electropherotypes occurring between rotavirus gastroenteritis epidemics in central Australia
Authors: Schnagl R D , Rodger S M , Holmes I H
Published: January 2020

The changes in human rotavirus electropherotypes, occurring during a period including two rotavirus gastroenteritis epidemics in 1976 and 1979 in relatively remote Central Australia, were determined by polyacrylamide gel electrophoretic analysis of the rotavirus genome ribonucleic acid. A number of different electropherotypes were present during each of the epidemics, although a single type was predominant in each one. The predominant electropherotype of the first epidemic persisted in the area for approximately 2 years afterwards. Apart from this electropherotype, only three others were recognized in the 3 years between the two epidemics. One of these, first seen 1 year before the second epidemic, bore a very close similarity to the predominant type of the second epidemic. Altogether, 12 different electropherotypes were recognized during the period of the survey. No type common to both areas was found when rotavirus electropherotypes recognized in Central Australia were compared with those detected in a 1973-to-1979 survey in Melbourne, Australia.