bluuebunny/crossref_metadata_2025 huggingface dataset:
Induction of hyperreactivity to endotoxin in mice by Coxiella burnetii
Authors: Schramek S , Kazar J , Sekeyova Z , Freudenberg M A , Galanos C
Published: January 2020

Intraperitoneal inoculation of mice with live or killed Coxiella burnetii phase I or phase II cells induced a marked hyperreactivity to the lethal effect of bacterial endotoxin and was accompanied by a marked hepatosplenomegaly. The degree and duration of hyperreactivity depended on the dose of C. burnetii administered and were higher with phase I than with phase II cells. Sensitization to the lethal effects of endotoxin and induction of splenomegaly by phase I C. burnetii cells also proceeded in the endotoxin-resistant C3H/HeJ strain of mice. Preincubation of C. burnetii cells with the corresponding immune serum significantly diminished the ability of phase I but not phase II cells to induce hyperreactivity to endotoxin.
In vitro inhibition of murine macrophage migration by Bordetella pertussis lymphocytosis-promoting factor
Authors: Meade B D , Kind P D , Ewell J B , McGrath P P , Manclark C R
Published: January 2020

Lymphocytosis promoting factor (LPF) of Bordetella pertussis is a protein toxin which may have a role in the pathogenesis of pertussis. Since macrophages have an important role in the control of respiratory infections, the in vitro effects of LPF on macrophages from C3H/HeN and C3H/HeJ mice and on a murine macrophage-like cell line, RAW264, were examined. LPF inhibited random migration of resident peritoneal macrophages as well as the chemotaxis of peritoneal macrophages and the cell line. Fifty percent inhibition of chemotaxis occurred at 0.2 to 0.3 ng of LPF per ml for the macrophages and at 1 to 2 ng of LPF per ml for the cell line. When LPF was either heated at 80 degrees C for 5 min or premixed with specific antibodies, it failed to inhibit migration. At 20 ng/ml, LPF inhibited chemotaxis by more than 80% and also decreased Fc-mediated phagocytosis by 25 to 35%. At this dose, LPF was not a chemoattractant for murine macrophages and did not reduce macrophage viability, adherence, or opsonized zymosan-stimulated superoxide release. When LPF-treated macrophages were added to tissue culture dishes and then examined microscopically after 4 h, the LPF-treated cells adhered but failed to spread and elongate as well as control macrophages. These data indicate that LPF specifically inhibits macrophage migration in vitro and suggest that a possible role for LPF in pathogenesis is to inhibit migration of macrophages to the site of B. pertussis infection.
Role of iron in intracellular growth of Trypanosoma cruzi
Authors: Loo V G , Lalonde R G
Published: January 2020

Host hypoferremic responses occur during infection with Trypanosoma cruzi, presumably through the transfer of iron to the sites of intracellular parasite replication. Depletion of host intracellular iron stores reduces parasite pathogenicity. It has therefore been hypothesized that T. cruzi requires iron for optimal growth in host cells and that, unlike extracellular pathogens, T. cruzi may benefit from host hypoferremic responses. These hypotheses were examined by the in vitro infection of peritoneal macrophages with T. cruzi. Various doses of desferrioxamine or referrated desferrioxamine were added to the culture medium, and parasite growth was monitored. The influence of treatment on uninfected macrophage morphology, function, and iron content was also verified. Desferrioxamine reduced the rate of amastigote replication in a dose-dependent fashion, whereas referrated desferrioxamine did not. The iron content of desferrioxamine-treated macrophages was decreased by 55% without provoking significant morphological or functional changes. Thus, amastigotes used host cell iron stores for optimal growth, and desferrioxamine reduced growth by depleting host cell iron. Hence, it was suggested that depletion of host intracellular iron stores may protect against T. cruzi and, furthermore, that host responses which transfer iron to the intracellular sites of T. cruzi replication may enhance parasite pathogenicity.
Bacteriology of experimental gingivitis in children
Authors: Moore W E , Holdeman L V , Smibert R M , Cato E P , Burmeister J A , Palcanis K G , Ranney R R
Published: January 2020

Children are more resistant to gingivitis than are adults. To determine possible differences in their periodontal floras, an experimental gingivitis study, identical in design to one reported earlier with young adults, was conducted with four 4- to 6-year-old children. The incidence of sites that developed gingival index scores of 2 in children was less than one-third of the incidence observed in adults. The composition of the flora of each child was statistically significantly different from that of any other child or adult. The floras of the children as a group were statistically significantly different from those of the adults. Children had 3-fold greater proportions of Leptotrichia species, 2.5-fold greater proportions of Capnocytophaga species, 2.3-fold greater proportions of Selenomonas species, 2-fold greater proportions of bacterial species that require formate and fumarate, and 1.5-fold greater proportions of Bacteroides species. Adults had greater proportions of Fusobacterium, Eubacterium, and Lactobacillus species. Fusobacterium nucleatum, Actinomyces WVa 963, Selenomonas D04, and Treponema socranskii were predominant species that correlated with increasing gingival index scores in both children and adults.
Anaerobic growth of Neisseria gonorrhoeae coupled to nitrite reduction
Authors: Knapp J S , Clark V L
Published: January 2020

A total of 204 Neisseria gonorrhoeae strains, including 39 penicillinase-producing strains, representing 64 distinct auxotype and serovar classes were tested for their ability to grow anaerobically with nitrite as a terminal electron acceptor. All strains grew anaerobically with subtoxic concentrations of nitrite, and all penicillinase-producing strains produced beta-lactamase when grown anaerobically. Nitrite reductase was produced constitutively under aerobic conditions in the absence of nitrite, and cytochrome oxidase was produced constitutively under anaerobic conditions. Strains could not grow anaerobically with sulfite as a terminal electron acceptor. Strain NRL 905 grew anaerobically in broth medium containing nitrite at a rate comparable to its growth rate under aerobic conditions. The feasibility and significance of in vivo anaerobic growth of N. gonorrhoeae is discussed.
Recovery of aerobic and anaerobic bacteria from irradiated mice
Authors: Brook I , MacVittie T J , Walker R I
Published: January 2020

Anaerobic and aerobic bacteria were often found as mixed infections in 225 lethally irradiated mice. Of a total of 57 mice that were sacrificed, aerobic bacteria were recovered exclusively in 9 (27%) of the 34 culture-positive mice, anaerobic bacteria were recovered exclusively in 15 (44%), and mixed aerobic and anaerobic flora were recovered in 10 (29%). The predominant organisms were anaerobic cocci Escherichia coli, Proteus mirabilis, Staphylococcus spp., and Bacteroides spp.
Influence of steroidal and nonsteroidal sex hormones on host resistance in mice: increased susceptibility to Listeria monocytogenes after exposure to estrogenic hormones
Authors: Pung O J , Luster M I , Hayes H T , Rader J
Published: January 2020

Subchronic exposure to pharmacological levels of estrogenic compounds, including 17 beta-estradiol, diethylstilbestrol, and alpha-dienestrol, significantly increased the mortality of B6C3F1 female mice after Listeria infection. Compounds with little estrogenic activity, including 5 alpha-dihydrotestosterone, progesterone, zearalenol, and corticosterone, did not alter Listeria-related mortality. Estrogen-induced alterations in resistance were inhibited by both adult thymectomy and the estrogen antagonist tamoxifen. Estrogen exposure depressed the accumulation of monocytes and lymphocytes at infective foci. Significantly elevated numbers of bacteria were observed in infective foci of estrogen-treated mice later in the infection when bacteria were nearly eliminated from untreated animals. These results indicate that estrogen-induced suppression of Listeria immunity is partially mediated by the thymus, probably through receptor events which may ultimately suppress the activation of T cell-dependent defense mechanisms. This may be partially reflected by the inability of estrogen-exposed mice to eliminate Listeria cells or to accumulate mononuclear effector cells at infective foci at the same rate as controls.
Cloning of enterotoxin gene from Aeromonas hydrophila provides conclusive evidence of production of a cytotonic enterotoxin
Authors: Chakraborty T , Montenegro M A , Sanyal S C , Helmuth R , Bulling E , Timmis K N
Published: January 2020

Culture filtrates of two Aeromonas hydrophila strains which were isolated from patients with diarrhea and assumed to be causative agents of the infections were shown to contain enterotoxic, cytotoxic, and hemolytic activities. Modest heat treatment of the filtrates inactivated the cytotoxic and cytolytic activities, but not the enterotoxic activity. The construction of cosmid gene banks in Escherichia coli of DNA from both A. hydrophila strains demonstrated that the determinants of the three activities are located on three different segments of the A. hydrophila chromosome. Both heated culture filtrates of A. hydrophila and nonheated filtrates of an E. coli clone containing the A. hydrophila enterotoxin gene provoked fluid accumulation in the rabbit ileal loop and suckling mouse models and caused elongation of Chinese hamster ovary cells. Differences in the responses of the models to the A. hydrophila enterotoxin and to the heat-labile and heat-stabile toxins of E. coli indicated that the former is distinct from the latter two types of toxin. These results constitute conclusive evidence for the production by A. hydrophila of a cytotonic enterotoxin that is distinct from the A. hydrophila cytotoxin and hemolysin and known E. coli enterotoxins.
Construction of a potential live oral bivalent vaccine for typhoid fever and cholera-Escherichia coli-related diarrheas
Authors: Clements J D , El-Morshidy S
Published: January 2020

We used the Salmonella typhi galactose epimerase (galE) mutant strain Ty21a, shown to be a safe, effective, living, attenuated oral typhoid vaccine, as a recipient for a recombinant plasmid containing the gene for production of the nontoxic B subunit of the heat-labile enterotoxin of Escherichia coli. The S. typhi derivative, strain SE12, produced heat-labile enterotoxin subunit B that was structurally and immunologically indistinguishable from heat-labile enterotoxin subunit B produced by strains of E. coli harboring the same plasmid. Tests in mice and guinea pigs showed that strain SE12 was safe when given orally and was capable of inducing a significant antitoxic antibody response when injected parenterally. Moreover, it retained the galactose sensitivity of the parent strain, preserving its utility as a typhoid vaccine. This strain may prove to be a useful live oral bivalent vaccine strain for typhoid fever and cholera-E. coli-related diarrheas.
Presence of toxic shock toxin in toxic shock and other clinical strains of Staphylococcus aureus
Authors: Reeves M W , Pine L , Feeley J C , Wells D E
Published: January 2020

Toxic shock toxin (TST), also known as pyrogenic exotoxin C (Schlievert et al., J. Infect. Dis. 143:509-516, 1981) and staphylococcal enterotoxin F (Bergdoll et al., Lancet i:1017-1021, 1981), was purified from toxic shock strains of Staphylococcus aureus by preparative isoelectric focusing and by chromatofocusing. Neither method produced an absolutely pure protein as determined by silver staining of sodium dodecyl sulfate-acrylamide gels, although chromatofocusing was the better method of the two. Three molecular weight variants of the protein were found in the two toxic shock syndrome strains that were studied, regardless of the purification method that was used. An isoelectric point of 7.15 and molecular weights of 21,400, 22,100, and 23,200 were determined for the different forms of the protein from electrophoresis data. A sedimentation coefficient of 2.3S was determined by sucrose gradient centrifugation, and a Stokes radius of 2 X 10(-7) cm was determined by gel filtration. An average molecular weight of 18,900 for all of the TST forms was calculated from these data by the Stokes-Einstein equation. A survey for TST in 32 control and 46 toxic shock strains of S. aureus by isoelectric focusing and by agarose gel double immunodiffusion with specific rabbit antiserum revealed that the isoelectric focusing method tends to overestimate the number of TST-positive strains because of the detection of non-TST, neutral staphylococcal proteins. Based on immunodiffusion data, the association of TST with toxic shock strains was found to be 100% in vaginal isolates and 62% in non-vaginal isolates. In the control strains, TST was found in 16% of the vaginal strains and 23% of the non-vaginal strains. The value of this toxin as a marker for toxic shock and its relationship to the pathogenesis of this disease are discussed.
Primary sequence of the alpha-toxin gene from Staphylococcus aureus wood 46
Authors: Gray G S , Kehoe M
Published: January 2020

The complete DNA sequence of a cloned alpha-toxin gene from Staphylococcus aureus was determined. The amino acid sequence of the alpha-toxin protein, predicted from the DNA sequence, was described and compared with published data. The primary product of the cloned alpha-toxin gene contained a 26-amino-acid leader sequence which possessed characteristic features of a signal sequence involved in secretion. The mature alpha-toxin protein had a molecular size of 33,000 and contained only three short regions of high hydrophobicity in addition to a number of short, weakly hydrophobic regions.
A role for rheumatoid factor enhancement of Plasmodium falciparum schizont inhibition in vitro
Authors: Green T J , Packer B J
Published: January 2020

Studies were undertaken to determine whether rheumatoid factor (RF) was present in immune human and Aotus trivirgatus monkey sera which inhibited Plasmodium falciparum schizonts in vitro and to determine whether RF could be responsible for or contribute to merozoite agglutination in the parasite inhibition test. Additional studies were conducted to determine the effect of exogenous RF on schizont inhibition when used alone or in conjunction with immune or normal sera. RF was not detected in any of the 11 immune monkey sera or the 3 immune human sera which were tested. However, when RF was added to immune human or Aotus sera, levels of schizont inhibition increased significantly over levels obtained with immune serum alone. When RF was used alone or in conjunction with normal sera, levels of schizont inhibition were comparable to those obtained with normal serum. Furthermore, adsorption of the RF with immunoglobulin G-coated erythrocytes removed the enhancing activity. The results of this study indicate that RF, which is sometimes produced during acute or chronic malarial infection, may contribute nonspecifically to the enhanced clearance of plasmodia in vivo.
Lymphocytosis-promoting factor of Bordetella pertussis alters mononuclear phagocyte circulation and response to inflammation
Authors: Meade B D , Kind P D , Manclark C R
Published: January 2020

Previous results from our laboratory demonstrated that purified lymphocytosis-promoting factor (LPF), a protein toxin from Bordetella pertussis, inhibited the migration of murine macrophages in vitro. The current study examined the in vivo effects of LPF on mononuclear phagocyte circulation and response to an inflammatory stimulus. Intravenous injection of mice with 200 ng of LPF produced a prolonged monocytosis which peaked with a fivefold increase on day 5 after injection. LPF (200 ng) also inhibited by more than 75% the increase in peritoneal inflammatory macrophages induced by intraperitoneal injection of thioglycolate broth, phytohemagglutinin, or paraffin oil. The inhibition was significant when thioglycolate was given 1 h or 2 or 4 days after LPF but not when thioglycolate was given 2 or 4 days before LPF. The LPF-induced monocytosis on day 5 after injections was not altered by the intraperitoneal injection of thioglycolate broth. The leukocytosis-promoting and macrophage-inhibiting properties of LPF were the same in N:NIH(S) and C3H/HeJ mice. Treatments of LPF that reduced the leukocytosis-promoting effect of LPF also reduced the ability of LPF to inhibit the macrophage response. LPF doses sufficient to induce leukocytosis (greater than or equal to 25 ng) significantly inhibited the thioglycolate-induced increase in peritoneal macrophages. The results indicate that coincident with an LPF-induced monocytosis is a reduction in the number of mononuclear phagocytes at a site of inflammation. An in vivo inhibition of mononuclear phagocyte migration would explain both effects of LPF and is consistent with the in vitro inhibition of macrophage migration by LPF.
Protective role of intestinal flora against infection with Pseudomonas aeruginosa in mice: influence of antibiotics on colonization resistance
Authors: Hentges D J , Stein A J , Casey S W , Que J U
Published: January 2020

Swiss white mice were given ampicillin, clindamycin, kanamycin, metronidazole, or streptomycin in drinking water for a period of 3 weeks. One week after the initiation of antibiotic administration, the treated mice and untreated control mice were challenged orally with approximately 10(8) viable, streptomycin-resistant (SR) Pseudomonas aeruginosa isolates. All five of the antibiotics decreased the resistance of the mice to intestinal colonization with SR P. aeruginosa, as reflected by an increased fecal carriage of the organism and an increase in population levels of SR P. aeruginosa in feces as compared with untreated controls. Metronidazole was least effective in this regard. The antibiotics lowered the dose of SR P. aeruginosa that resulted in implantation in 50% of the mice ID50 to various degrees. Administration of streptomycin, the most effective antibiotic, caused a 10,000-fold decrease in ID50 as compared with untreated controls. Oral inoculation of approximately 10(8) organisms of SR P. aeruginosa resulted in translocation of the organism to the mesenteric lymph nodes, spleens, or livers of 13 or 17 streptomycin-treated mice, 1 of 20 clindamycin-treated mice, and 1 of 14 metronidazole-treated mice. Translocation was not observed, however, in ampicillin- or kanamycin-treated animals. Antibiotic activity was detected in the cecal contents of streptomycin-, kanamycin, and clindamycin-treated mice but not in the cecal contents of ampicillin- or metronidazole-treated animals.
Role of the carbohydrate domains of glycophorins as erythrocyte receptors for invasion by Plasmodium falciparum merozoites
Authors: Vanderberg J P , Gupta S K , Schulman S , Oppenheim J D , Furthmayr H
Published: January 2020

Solubilized preparations of purified glycophorins and specific domains of these molecules were assessed for their effects as inhibitors of Plasmodium falciparum invasion of human erythrocytes in vitro. The ability of newly invaded merozoites to continue developing and incorporating [3H]hypoxanthine during a 24-h period after their invasion was used as an assay for merozoite invasion. Glycophorins A, B, and C were found to be equally effective as inhibitors. Previous studies had shown N-acetylglucosamine, a sugar component of glycophorins A and C but not B, to be an effective inhibitor. Accordingly, molecular domains common to all of the glycophorins were further assessed. Sialic acid was shown to act almost as effectively as N-acetylglucosamine, presumably because of the structural similarities between these sugars. The inhibitory ability of sialic acid is considerably enhanced when presented to the parasite in a clustered form, as in an oligosaccharide. The acetyl group of these sugars does not appear to play an essential role in this inhibition. How the P. falciparum merozoite recognizes and interacts with the sugar domains of the glycophorin molecule remains to be determined.
Production of neutralizing monoclonal antibodies to Escherichia coli heat-stable enterotoxin
Authors: Brandwein H , Deutsch A , Thompson M , Giannella R
Published: January 2020

In an effort to develop new approaches to the study and control of infectious diarrhea, we prepared murine monoclonal antibodies to the Escherichia coli heat-stable enterotoxin (STa). The toxin was purified from E. coli culture media and conjugated to bovine serum albumin. The STa-bovine serum albumin conjugate was used to immunize BALB/c mice, and the immune spleen cells from these mice were fused with SP2/0 myeloma cells. Resultant hybridomas were screened in an enzyme-linked immunosorbent assay protocol against 500 ng of STa-bovine serum albumin bound to microtiter wells as the solid-phase antigen. Five stable clones were selected and grown further in ascites fluid, which demonstrated anti-STa activity at dilutions of up to 1:500,000 in the enzyme-linked immunosorbent assay for heat-stable enterotoxin. In a competitive enzyme-linked immunosorbent assay format, the antibodies recognized several human and porcine strains of STa to various extents, but did not recognize E. coli heat-labile toxin, cholera toxin, or staphylococcal enterotoxin B. The antibodies were all able to bind lactoperoxidase-labeled [125I]STa, and antibody 20B3 was also able to dissociate [125I]STa bound to toxin receptors on rat jejunal villous cells. Preincubation of STa with antibodies 20B3 or 20F5 led to a concentration-dependent neutralization of toxin activity in a suckling mouse intestinal secretion assay. These antibodies are likely to provide new tools for the continued study of STa structure-function relationships and may lead to improved diagnosis and treatment of E. coli-induced infectious diarrhea.
A minor high-molecular-weight outer membrane protein of Haemophilus influenzae type b is a protective antigen
Authors: Kimura A , Gulig P A , McCracken G H , Loftus T A , Hansen E J
Published: January 2020

Cell surface-exposed antigenic determinants of several high-molecular-weight outer membrane proteins of Haemophilus influenzae type b (Hib) have been shown to be consistently immunogenic in human infants convalescing from Hib meningitis. A monoclonal antibody (mab), 6G12, directed against one of these cell surface-exposed outer membrane proteins that has an apparent molecular weight of 98,000 (98K) was identified by radioimmunoprecipitation analysis. Of 120 clinical isolates of Hib, 83 were found to possess antigenic determinants which reacted with mab 6G12 in a colony blot-radioimmunoassay procedure, indicating that the antigenic determinant recognized by mab 6G12 is present in the majority of Hib strains. A different radioimmunoassay, which uses whole Hib cells as antigen, confirmed that strains reactive with mab 6G12 in the colony blot-radioimmunoassay procedure possessed a cell surface-exposed and antibody-accessible antigenic determinant recognized by this mab. Hib strains which did not react with mab 6G12 were found to lack a 98K protein. Passive immunization with mab 6G12 reduced the level of bacteremia that developed in infant rats challenged with the homologous Hib strain against which this mab was raised. In contrast, no protection was observed when the challenge strain was one which lacks the antigenic determinant recognized by mab 6G12. Radioimmunoprecipitation analysis of sera from human infants convalescing from Hib meningitis detected an antibody response directed against the 98K protein. The protection against experimental Hib disease provided by antibody to the 98K protein, the immunogenicity of this protein in human infants, and its presence in a majority of Hib strains indicate that the 98K outer membrane protein may have potential for vaccine development.
Virulence of human and bovine isolates of group B streptococci (types Ia and III) in experimental pregnant mouse models
Authors: Poutrel B , Dore J
Published: January 2020

Two experimental mouse models were tested for their suitability in measuring virulence of two human and two bovine isolates (types Ia and III) of group B streptococci. In the first model, the kinetics of the number of bacteria in the spleen, liver, and placenta of mice inoculated intravenously on day 16 of pregnancy were monitored for 48 h after infection. In the second model, lethality and abortion were recorded for mice inoculated on day 13 of pregnancy. Levels of colonization in spleens or livers and lethality were significantly greater (P less than 0.001) for human isolates than for bovine isolates. In contrast, no statistically significant differences in the ability to colonize placentas and to induce abortions were noted between human and bovine isolates. The results showed that pregnant mice were more sensitive than nonpregnant mice to a challenge with group B streptococci. The results also suggest that placental colonization and abortion could be a suitable mouse model in evaluating the virulence of human and bovine isolates of group B streptococci.
Anaerobiosis increases resistance of Neisseria gonorrhoeae to O2-independent antimicrobial proteins from human polymorphonuclear granulocytes
Authors: Casey S G , Shafer W M , Spitznagel J K
Published: January 2020

We investigated the in vitro resistance of Neisseria gonorrhoeae FA19 to the O2-independent antimicrobial systems of human polymorphonuclear leukocytes. Acid extracts of polymorphonuclear leukocyte granules (crude granule extracts) and a purified granule protein (57 kilodaltons) were, at low concentrations, bactericidal for gonococci under aerobic conditions that permitted growth. However, they were less effective under anaerobic conditions that imposed bacteriostasis. We found that adding sodium nitrite to reduced growth media permitted the growth of strain FA19 in an anaerobic environment. Under these conditions with nitrite, anaerobic cultures of strain FA19 were no more resistant to the crude granule extract and the 57-kilodalton protein than aerobic cultures. In contrast, Salmonella typhimurium SL-1004, a facultative anaerobe, was readily killed by both the crude granule extract and the 57-kilodalton antimicrobial protein regardless of the presence or absence of free molecular oxygen. This is the first demonstration that an isolated antimicrobial protein from polymorphonuclear leukocyte granules is active against bacteria under anaerobic conditions. Our results also indicated that the efficacy of human polymorphonuclear leukocyte O2-independent killing of N. gonorrhoeae may, in part, be inhibited by bacteriostatic conditions imposed by hypoxia.
Isolation, propagation, and characterization of a newly recognized pathogen, cilia-associated respiratory bacillus of rats, an etiological agent of chronic respiratory disease
Authors: Ganaway J R , Spencer T H , Moore T D , Allen A M
Published: January 2020

A Gram-negative, filamentous, rod-shaped bacillus which failed to grow in cell-free media was isolated in apparently pure culture from the bronchial scraping and washing of a laboratory rat suffering from chronic respiratory disease by inoculating embryonated chicken eggs via the allantoic route. None of the embryos died during 20 serial passages at weekly intervals. The bacillus was reisolated in embryonated eggs from cesarean-derived barrier-maintained N:SD(SD) rats 8 and 12 weeks after intranasal inoculation with 10th-passage allantoic fluid. The inoculated rats were housed in Horsfall-type units and remained free from other known respiratory pathogens, including mycoplasmas and murine viruses, throughout the study. The bacillus colonized the ciliated epithelial cells of the respiratory tract and caused a marked peribronchial infiltration and hyperplasia of mononuclear cells which progressed with time. The bacillus, ca. 0.2 micron wide by 4 to 6 micron long, stained very poorly with basic aniline dyes but was readily demonstrated with the Warthin-Starry silver technique. It was heat labile (56 degrees C for 30 min); spore forms were not observed. It withstood freeze-thawing and was successfully stored at -70 degrees C. Although no visible means of locomotion was observed with the electron microscope, a slow gliding motility, sometimes with bending and flexing of bacilli apparently adherent to the glass surface, was observed with phase microscopy. As an etiological agent of chronic respiratory disease of rats, this cilia-associated respiratory bacillus (tentatively designated the CAR bacillus) may be the first recognized gliding bacterium known to cause disease in a warm-blooded vertebrate.
Penicillinase plasmid-linked genetic determinants for enterotoxins B and C1 production in Staphylococcus aureus
Authors: Altboum Z , Hertman I , Sarid S
Published: January 2020

The genes encoding for beta-lactamase (bla+) and resistance to metallic ions (cadmium, mercury, lead, arsenate, and arsenite) were located in a 56.2-kilobase plasmid, pZA10, isolated from a clinical strain, Staphylococcus aureus 6344. This strain produced enterotoxin B and enterotoxin C1. Elimination of pZA10 by either sodium dodecyl sulfate or heat treatment (43 degrees C) resulted in the loss of the capability of the bacteria to produce both enterotoxin B and enterotoxin C1. A physical map of pZA10 was constructed with BamHI, SalI and BglII restriction endonucleases. Penicillin-resistant, enterotoxin B- and C1-producing cotransformants were isolated by transformation with pZA10 DNA with either S. aureus RN450 or cured S. aureus 6344 as recipients. The transferred plasmids exhibited genetic instability shown by changes in restriction pattern and molecular size, loss of plasmid DNA, and addition of chromosomal DNA. Enterotoxin B production was related to a 18.1-kilobase pZA10 fragment carried by such a rearranged plasmid. Chromosomal cointegration of bla+ with genetic determinants for metallic ion resistance and enterotoxin B and C1 production were detected in heat-treated S. aureus 6344. Transformation employing chromosomal DNA containing the integrated plasmid resulted in excision and reestablishment of pZA10-related plasmids in the transformants. pZA10-linked resistance to cadmium, which was lost upon the integration of pZA10 into the host chromosome, reappeared in transformants carrying the excised plasmid.
Reaction of human sera with Eubacterium brachy: isolation and characterization of an extracellular antigen
Authors: Vincent J W , Falkler W A , Dalessandro N F , Miller R A , Heath J R
Published: January 2020

Recent studies have demonstrated an association of Eubacterium sp. with the subgingival microflora of patients with chronic periodontitis. One species, Eubacterium brachy, was evaluated to determine the possible mechanisms by which this microorganism may contribute to these diseases. Of 167 sera evaluated by double diffusion in agar, 20.8% displayed reactivity with a sonicated preparation of E. brachy. An extracellular antigen was identified in the culture supernatant fluid which reacted with antibodies in human sera. This antigen was isolated by methanol precipitation and purified by gel filtration. When tested by an enzyme-linked immunosorbent assay, all sera displayed some reactivity. Lines of identity were not shared with other species of Eubacterium, but were shared with other clinical isolates of E. brachy. The reactive antibody was identified as immunoglobulin G by immunoelectrophoresis, verified by enzyme-linked immunosorbent assay, and found to be capable of complement fixation. The monosaccharides and amino acids of the extracellular antigen were identified by high-pressure liquid chromatography. This antigen was shown to have a molecular weight of 170,000 and to share a line of identity with the sonicated preparation of E. brachy. The possible role of the organism in the immunopathology of periodontal diseases is discussed.
Acquired ability of Staphylococcus aureus to produce toxic shock-associated protein and resulting illness in a rabbit model
Authors: Rasheed J K , Arko R J , Feeley J C , Chandler F W , Thornsberry C , Gibson R J , Cohen M L , Jeffries C D , Broome C V
Published: January 2020

Staphylococcus aureus from patients with toxic shock syndrome (TSS) produce TSS toxin 1. We transferred, by a bacteriophage, the ability to produce TSS toxin 1 from a TSS toxin 1-positive to a TSS toxin 1-negative strain of S. aureus. This recombinant strain produced TSS toxin 1 as confirmed by isoelectric focusing, immunodiffusion, radioimmunoassay, and autoradiography. The recombinant produced TSS-like illness in rabbits, and was significantly (P less than 0.001) more lethal than the recipient strain. Both strains produced fever and diarrhea, but, in addition, rabbits challenged with the recombinant also developed lowered blood pressure (P = 0.002), conjunctival hyperemia, erythroderma, and respiratory distress. Histopathological findings in rabbits challenged with the recombinant strain were remarkably similar to those described for humans with TSS, e.g., erythrophagocytosis, liver "triaditis," and vasodilatation. This study demonstrates that this protein may contribute to the pathogenesis of the TSS.
Mucosal nasopharyngeal immune responses of horses to protein antigens of Streptococcus equi
Authors: Galan J E , Timoney J F
Published: January 2020

Mucosal nasopharyngeal immunoglobulin A (IgA) and IgG responses to proteins of Streptococcus equi were studied in horses after the experimental production of strangles. S. equi-specific IgA and IgG titers in nasopharyngeal mucus were much higher in samples from animals 1 to 2 weeks after challenge than in samples from control animals. Although IgA was the major immunoglobulin in nasal mucus, there was more antibody activity associated with IgG as measured by radioimmunoassay. Great differences between the specificities of antibodies in nasal mucus and in serum were detected. IgA and IgG of mucus origin recognized only two major proteins with molecular weights of about 41,000 and 46,000 in acid extracts of S. equi and gave no detectable reaction with culture supernatant proteins. Only one protein of about 62,000 molecular weight was recognized in acid extracts of an equine strain of S. zooepidemicus. In contrast, immunoglobulins in serum recognized a great variety of proteins in culture supernatants and acid extracts of S. equi and S. zooepidemicus which did not include those proteins recognized by immunoglobulins in mucus. These findings provide good evidence for the independence of the local and systemic immune responses of the horse to S. equi. Horses rechallenged shortly after recovery from the first infection were resistant to challenge with an inoculum of S. equi 10 times greater than that to which they were originally susceptible. This resistance appeared to be independent of the levels of bactericidal antibody in serum. We therefore suggest that immunity to S. equi infection is mediated by locally produced nasopharyngeal antibodies.
Role of fibronectin in human monocyte and macrophage bactericidal activity
Authors: Proctor R A , Textor J A , Vann J M , Mosher D F
Published: January 2020

Fibronectin is a high-molecular-weight glycoprotein found as a soluble dimer in plasma and as an insoluble multimer in tissues. It has been proposed that plasma fibronectin facilitates phagocytic removal of lysed cells and damaged tissues. Fibronectin binds avidly to several species of gram-positive bacteria and enhances staphylococcal and streptococcal attachment to cultured cells. Determination of whether fibronectin will enhance the bactericidal activity of monocytes and macrophages has not been reported. The bactericidal activity of freshly isolated monocytes, cultured monocytes, or lymphokine-activated macrophages was tested in the presence of either dimeric or multimeric fibronectin. Freshly isolated monocytes and lymphokine-activated macrophages killed Staphylococcus aureus effectively in the absence of fibronectin or whole serum. In contrast, monocytes cultured for 7 to 10 days had diminished staphylocidal capacity. When the monocytes were cultured with either dimeric or multimeric fibronectin, however, bactericidal capacity was maintained. Thus, although fibronectin did not enhance the bactericidal activity of mononuclear phagocytes, both multimeric and dimeric fibronectin were effective at maintaining the bactericidal capacity.
Passage of Salmonella enteritidis and Salmonella thompson through chick ileocecal mucosa
Authors: Popiel I , Turnbull P C
Published: January 2020

The passage of Salmonella enteritidis and S. thompson across the cecal mucosa has been visualized in an electron microscope study with the freshly hatched chick as a model. The uptake of salmonellae by macrophages took place in the cecal lumen; the macrophages became abnormal and often ruptured to release organisms back into the lumen. The entry of bacteria into the epithelial cells was associated with a series of pathological changes, beginning with the appearance of active Golgi apparatus and the production of a variety of lysosomal vesicles. Salmonellae became sequestered within lysosomes but were unaffected by the presence of hydrolytic enzyme. Epithelial cell death was related to particularly large numbers of bacteria. Fragments of invaded epithelial cells, especially those undergoing cell death, contributed to the cytoplasmic debris and released further salmonellae into the lumen. Bacteria were never observed in large numbers below the basement membrane, and there was no significant pathology in the lamina propria tissue. Wandering cells, identified as macrophages and containing the bacteria, were observed spanning the epithelial and lamina propria regions through breaks in the basement membrane. It is suggested that the passage of bacteria from the epithelium to the lamina propria is primarily the result of capture and transport within host macrophages.
Cyclic development of immunological memory to bacterial lipopolysaccharide
Authors: Baker P J , Hiernaux J R , Stashak P W , Rudbach J A
Published: January 2020

Immunological memory to the lipopolysaccharide of Escherichia coli O113 was generated in strains of inbred mice given a single subimmunogenic dose of either E. coli O113 lipopolysaccharide or the native protoplasmic polysaccharide of E. coli O113. Such memory, which only involved antibody of the immunoglobulin M class, developed in a cyclic manner that was characteristic for the strain of mice used. It involved cell proliferation as well as differentiation and persisted for at least 25 days after priming with a single injection of a subimmunogenic dose of E. coli O113 lipopolysaccharide.
Effect of streptomycin administration on colonization resistance to Salmonella typhimurium in mice
Authors: Que J U , Hentges D J
Published: January 2020

The addition of 5 mg of streptomycin sulfate per ml to the drinking water of Swiss white mice resulted in a 100,000-fold reduction in the 50% implantation dose of streptomycin-resistant Salmonella typhimurium for the animals. When streptomycin-treated and untreated mice were challenged orogastrically with 10(3) viable S. typhimurium organisms, 100% of the treated and none of the untreated mice excreted the pathogen in their feces. Similarly, translocation of S. typhimurium from the intestinal tract to the liver, spleen, and mesentery occurred in 10 of 10 treated mice but in none of the untreated mice 7 days after challenge with 10(3) CFU. Studies of colonization dynamics showed that S. typhimurium was present at high population levels in the intestines of streptomycin-treated mice and in detectable levels in the liver, spleen, and mesentery within 72 h after challenge with 10(3), 10(5), or 10(8) organisms. In untreated mice challenged with either 10(3) or 10(5) S. typhimurium organisms, the organisms were isolated from ileal and cecal tissues but not from ileal or cecal contents or from extraintestinal tissue 72 h after challenge. When untreated mice were challenged with 10(8) organisms, however, S. typhimurium was present in all organs and in intestinal contents. Streptomycin treatment, therefore, facilitated colonization and development of streptomycin-resistant S. typhimurium populations in intestines of mice and the subsequent translocation of the organisms from the intestinal tract to other tissues.
Simultaneous loss of bacteriophage receptor and coaggregation mediator activities in Actinomyces viscosus MG-1
Authors: Tylenda C A , Enriquez E , Kolenbrander P E , Delisle A L
Published: January 2020

Actinomyces bacteriophages were used as tools to study coaggregation between actinomyces and streptococci. Four bacteriophage isolates, phages AV-1, AV-2, AV-3, and 1281, bound to coaggregation group A Actinomyces viscosus and to group E A. naeslundii. No binding to groups B, C, D, or F was observed. Only A. viscosus MG-1 was capable of supporting a productive infection by these phages. Spontaneously occurring bacteriophage-resistant mutants of A. viscosus MG-1 were isolated and were shown to fall into two classes. Class I mutants were resistant to all four phages, whereas class II mutants were resistant only to phage AV-3. In each case, strains resistant to a particular phage were unable to bind that phage, suggesting that a loss or alteration of the cell surface phage receptor had occurred. Both classes of mutants were unable to coaggregate with streptococci representing coaggregation group 1 and had also lost the ability to mediate one type of coaggregation with group 4 streptococci. Class II mutants also were unable to coaggregate with group 2 streptococci. Lactose-inhibitable interactions with other streptococci (groups 3 and 4) were unchanged in the mutants. The simultaneous loss of sensitivity to phage AV-3 and the ability to coaggregate with coaggregation group 1 streptococci suggests the possibility of a relationship between these two cell surface structures.
Transfer of the virulence plasmid of Yersinia pestis to Yersinia pseudotuberculosis
Authors: Wolf-Watz H , Portnoy D A , Bölin I , Falkow S
Published: January 2020

Transposon Tn5 insertion derivatives of the virulence plasmid pYV019 of Yersinia pestis were transferred by P1 transduction into a plasmid-free strain of Y. pseudotuberculosis. One of these plasmid derivatives conferred virulence upon the Y. pseudotuberculosis strain. This strain had the ability to express temperature-inducible plasmid-coded outer membrane proteins and was also found to be Ca2+ dependent.
Haemophilus influenzae can use human transferrin as a sole source for required iron
Authors: Herrington D A , Sparling P F
Published: January 2020

Haemophilus influenzae grown on enriched medium containing protoporphyrin IX rather than hemin was iron starved by the addition of the chelator ethylenediamine di-o-hydroxyphenylacetic acid. Iron starvation could be overcome in each of 33 H. influenzae type b isolates by 30% Fe-saturated human transferrin but not by human lactoferrin. Among nontypeable H. influenzae, 28 of 35 isolates, including 2 of 3 systemic isolates, were able to utilize Fe-transferrin. None of 18 H. parainfluenzae isolates was able to use Fe-transferrin. Iron starvation of H. influenzae type b resulted in increased amounts of three membrane proteins of 94,000 to 98,000 daltons.
Naturally acquired immunity to tetanus toxin in an isolated community
Authors: Matzkin H , Regev S
Published: January 2020

Literature on natural immunity to tetanus is scarce. We examined antitetanus antibody levels with the enzyme-linked immunosorbent assay in 200 people living in an isolated community and clarified the influence of age and sex on immunity. In 197 subjects, antitoxin antibodies were measured. No sex differences were noted, and 30% had protective levels (above 0.01 IU/ml). The percentage of those considered protected was age dependent.
Detection of circulating antigens in sera of rabbits infected with Toxoplasma gondii
Authors: Ise Y , Iida T , Sato K , Suzuki T , Shimada K , Nishioka K
Published: January 2020

Experiments were performed to investigate the usefulness of an enzyme-linked immunosorbent assay utilizing avidin-biotin interaction as a diagnostic tool for detection of Toxoplasma antigen in blood. The lower limit of sensitivity of the assay by this method was ca. 4 ng/ml, and standard assays provided a linear plot of antigen concentration over a range up to 250 ng/ml. In rabbits inoculated subcutaneously with trophozoites of the RH strain, Toxoplasma antigen became demonstrable in the circulation 3 days after injection, before emergence of antibody in serum and development of parasitemia. Analysis of the antigen in serum from infected rabbits by high-permeation liquid gel chromatography suggested the occurrence of antigens of four different molecular weights, greater than or equal to 400,000, 220,000, 130,000, and 45,000. Of these antigens, those of molecular weights 220,000 and 130,000 showed a conspicuous elevation with time after infection.
Promotion of Streptococcus mutans glucose transport by human whole saliva and parotid fluid
Authors: Germaine G R , Tellefson L M
Published: January 2020

Human saliva and parotid fluid have two effects on glucose uptake by Streptococcus mutans: a reduction in the overall rate of uptake, and the promotion of a biphasic mode of uptake. The former effect had been previously shown to result from lactoperoxidase-mediated inhibition of transport or metabolism or both. The objective of the present study was to uncover the basis of the second effect. Biphasic glucose uptake consisted of a rapid phase of low capacity and short duration (approximately 10 to 15 s) followed by a slower phase of high capacity and long duration (several minutes). The slow phase is typical of cells not exposed to the secretions (control cells). S. mutans BHT cells pretreated with as little as 10 microM glucose for 10 min at 37 degrees C, followed by its removal, subsequently exhibit biphasic glucose uptake typical of saliva- or parotid fluid-treated cells. Since pretreatment of the organism with glucose, whole saliva supernatant, or parotid fluid supported subsequent transport of the nonmetabolized glucose analog, 2-deoxyglucose, we concluded that pretreatments established a relatively stable pool of glycolytic intermediates (i.e., a phosphoenolpyruvate potential). Thin-layer chromatographic analysis of extracts from [14C]glucose-pretreated cells confirmed the presence of a stable pool of triose phosphates. Dialysis experiments indicated that high-molecular-weight substrates in the secretions were readily utilized by the organism to establish a phosphoenolpyruvate potential, especially when the lactoperoxidase system was rendered inactive. A survey of several carbohydrate constituents of salivary glycoproteins revealed that mannose, galactose, and N-acetylglucosamine, in addition to glucose, established phosphoenolpyruvate potentials in the organisms. Inactive substances included, among others, N-acetylgalactosamine and N-acetylneuraminic acid. In a survey of selected amino acids, arginine alone promoted 2-deoxyglucose accumulation by the organism, albeit feebly. Finally, it is argued that the phenomenon of biphasic glucose uptake provides evidence that the rate limiting step in glucose uptake by S. mutans is glucose metabolism and not glucose transport.