bluuebunny/crossref_metadata_2025 huggingface dataset:
Protection by Candida albicans of Staphylococcus aureus in the establishment of dual infection in mice
Authors: Carlson E , Johnson G
Published: January 2020

Candida albicans has been shown to stimulate infection in mice by a number of bacteria when both organisms are inoculated intraperitoneally (E. Carlson, Infect. Immun. 39:193-197, 1983). When subcutaneous and intraperitoneal inoculations were given with Staphylococcus aureus and C. albicans injected at opposite sites, mixed infection was established at the site of fungal inoculation but not at the site of the bacterial injection. Histopathologic evaluation of tissues for the presence of C. albicans and S. aureus after intraperitoneal inoculation of both showed fungal growth in the mesentery and omentum of the abdominal cavity. Cocci were numerous and always associated with the fungi, located within the fungal growth rather than at its periphery. It was concluded that this growth pattern in some way protected the bacteria and was the basis for the generalized fungal stimulation of the bacterial infections observed. In addition to C. albicans, Candida stellatoidea, Candida tropicalis, Candida parapsilosis, Torulopsis glabrata, and heat-inactivated C. albicans also demonstrated some ability to protect bacteria injected simultaneously, although C. parapsilosis and T. glabrata were less effective than the other yeasts in this respect.
A 28,000-dalton protein of normal mouse serum binds specifically to the inner core region of bacterial lipopolysaccharide
Authors: Brade L , Brade H
Published: January 2020

Normal mouse serum was found to contain a protein, referred to here as factor, which binds to the inner core region of lipopolysaccharides (LPSs) of various bacterial families. Since factor-LPS interactions resulted in activation of guinea pig complement, factor activity could be assayed by a passive hemolysis test with sheep erythrocytes coated with LPS or lipid A from Acinetobacter calcoaceticus (which was found earlier to bind particularly well to factor). Factor was purified by G-50 and hydroxyapatite chromatography whereby the specific hemolytic activity was enriched 1,675-fold. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions revealed the presence of a 28,000-dalton protein as the main band. The identity of this band was determined by absorption experiments with LPS-coated sheep erythrocytes or latex beads, whereby the 28,000-dalton band disappeared after specific absorption and could be recovered from the absorbent. The binding specificity of factor was determined in a passive hemolysis inhibition assay with defined oligosaccharides representative for the inner core region of LPS. Thus, the di- and trisaccharides alpha-D-mannoheptopyranosyl-(1----5)-2-keto-3-deoxy-D-mannoocto nic acid and alpha-D-mannoheptopyranosyl-(1----3)-alpha-D-mannoheptopyranosy l-(1----5)-2- keto-3-deoxy-D-mannooctonic acid, respectively, were able to inhibit binding of factor to LPS. The results are in accordance with our earlier observation that the heptose-2-keto-3-deoxy-D-mannooctonic acid region represents a common antigen of bacterial LPS. Rabbit hyperimmune serum directed against this common antigen and purified factor was found to exhibit the same specificity for LPS. Factor activity was followed in mice in vivo after injection of LPS; it disappeared completely 15 min after the injection of LPS and reappeared within 1 h.
Detection of antibodies against lipopolysaccharides of Escherichia coli and Salmonella R and S strains by immunoblotting
Authors: de Jongh-Leuvenink J , Vreede R W , Marcelis J H , de Vos M , Verhoef J
Published: January 2020

Antisera raised against several smooth and rough strains of Escherichia coli and Salmonella typhimurium were tested against lipopolysaccharides (LPS) of homologous and heterologous strains. The LPS were separated by sodium dodecyl sulfate-gel electrophoresis, transferred to nitrocellulose paper, and overlaid with antisera. The results showed that antisera raised against smooth strains reacted with high- as well as low-molecular-weight bands of their corresponding LPS and showed very few cross-reactions. Anti-E. coli J5 antiserum cross-reacted with few strains in the core region. But, anti-S. typhimurium Ra antiserum cross-reacted with many more strains. When these sera were absorbed with either the homologous- or a heterologous-positive strain, reactions were abolished. It appears that reactions of anti-E. coli J5 antiserum and anti-S. typhimurium Ra antiserum with homologous and heterologous strains were not due to the same antibody. This immunoblotting technique proved to be a useful method to distinguish different antibodies in antiserum raised against LPS of gram-negative bacteria.
Role of cholera toxin in enteric colonization by Vibrio cholerae O1 in rabbits
Authors: Pierce N F , Kaper J B , Mekalanos J J , Cray W C
Published: January 2020

The role of cholera toxin (CT) in mucosal colonization by Vibrio cholerae O1 was studied in rabbits by using toxinogenic V. cholerae and nontoxinogenic (A-B+ or A-B-) recombinant mutants derived from them. After oral inoculation, toxinogenic strains colonized intestinal mucosa significantly more efficiently than did either A-B- or A-B+ mutants; average colonization was increased 1.5- to 30-fold with toxinogenic strains, depending on the inoculum used and the portion of intestine studied. Additionally, colonization by an A-B- mutant was increased to the levels of its toxinogenic parent by coadministration of CT with the inoculum. We conclude that CT contributes significantly to mucosal colonization by V. cholerae and that this effect is not due to an interaction of the CT B subunit with its mucosal receptor. The possibility that this effect contributes to the in vivo selection of hypertoxinogenic variants of V. cholerae is considered.
Induction of alpha/beta interferon and gamma interferon in mice infected with Listeria monocytogenes during pregnancy
Authors: Nakane A , Minagawa T , Yasuda I
Published: January 2020

Alpha/beta interferon (IFN-alpha/beta) was induced in the bloodstream of mice 48 h after intravenous infection with Listeria monocytogenes, whereas IFN-gamma was induced in the bloodstream 6 h after stimulation with specific antigen on day 5 of infection in virgin mice. In contrast, no IFN-alpha/beta or IFN-gamma was produced in the bloodstream of pregnant mice after L. monocytogenes infection. However, unusual acid-labile IFN-alpha/beta instead of IFN-gamma was produced in some of the pregnant mice in response to specific antigen. The bacterial growth in the organs of pregnant mice in the early stage of infection was normal, but resulted in the delay of T-cell-dependent elimination of bacteria from the organs of pregnant animals in the late stage, and numerous bacteria were detected in both the placenta and the fetus. The significance of the IFN system induced by L. monocytogenes infection in pregnant mice is discussed.
Presence of common antigens, including major surface protein epitopes, between the cattle (intraerythrocytic) and tick stages of Anaplasma marginale
Authors: Palmer G H , Kocan K M , Barron S J , Hair J A , Barbet A F , Davis W C , McGuire T C
Published: January 2020

Epitopes of major surface proteins of the intraerythrocytic cattle stage of Anaplasma marginale were demonstrated in the midgut stage of the organism within the infective tick host Dermacentor andersoni. These proteins were common to all A. marginale isolates tested and at all stages of parasitemia. Sera from cattle immunized with the tick midgut stage of A. marginale immunoprecipitated multiple-erythrocyte-stage proteins, as demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The major proteins recognized (primarily greater than 14 and less than 200 kilodaltons [kDa]) included two major-erythrocyte-stage surface proteins of 36 and 105 kDa molecular size. To confirm the presence of common tick and erythrocyte A. marginale antigens with the immunized cattle sera, we purified the 36-kDa erythrocyte-stage protein by monoclonal immunoaffinity chromatography and developed an enzyme-linked immunosorbent assay based on the purified protein. All sera from cattle immunized with tick-stage A. marginale and cattle infected with various isolates of A. marginale developed antibodies to the 36-kDa protein. The potential immunoprophylactic, diagnostic, and epidemiologic value of the major epitopes common to both the invertebrate and mammalian stages of A. marginale, especially the 36-kDa protein, is discussed.
Viral contamination of a subline of Toxoplasma gondii RH
Authors: Grimwood B G
Published: January 2020

A subline of Toxoplasma gondii RH was determined to be contaminated with a viral agent, apparently lymphocytic choriomeningitis virus.
Effect of endogenous phosphoenolpyruvate potential on fluoride inhibition of glucose uptake by Streptococcus mutans
Authors: Germaine G R , Tellefson L M
Published: January 2020

The fluoride sensitivity of glucose uptake by whole cell suspensions of Streptococcus mutans was studied. Preincubation of the organism with up to 1 mM glucose markedly reduced the fluoride sensitivity of subsequent glucose uptake at pH 7.0 and 5.5. Glucose preincubation was shown to result in the establishment of a stable pool of three-carbon glycolytic intermediates. On the basis of inhibition studies and thin-layer chromatography of cell extracts, we suggest that 3- and 2-phosphoglycerate are the principal constituents of the pool. Increased concentrations of glucose used in preincubation mixtures was associated with increased pool sizes of the glycolytic intermediates and increased fluoride resistance. Transport of 2-deoxy-D-glucose by permeabilized cells was inhibited by fluoride when 2-phoshoglycerate served as the energy source. Increased concentrations of 2-phosphoglycerate were shown to overcome the fluoride inhibition of transport. The data suggest that establishment of a stable pool of glycolytic intermediates that includes 2-phosphoglycerate (or its progenitors) may contribute significantly to the apparent refractoriness of plaque microbes to fluoride in vivo.
Lipopolysaccharide structures in Enterobacteriaceae, Pseudomonas aeruginosa, and Vibrio cholerae are immunologically related to Campylobacter spp
Authors: Perez-Perez G I , Hopkins J A , Blaser M J
Published: January 2020

To determine whether lipopolysaccharide (LPS) structures of Campylobacter species are immunologically related to those of 11 other gram-negative organisms, we immunoblotted from polyacrylamide gels the LPS of these strains with immune rabbit serum raised against six Campylobacter jejuni strains and two Campylobacter fetus strains. The LPS studied were from Salmonella minnesota wild type and Ra to Re mutants, Salmonella typhi, Escherichia coli, Yersinia enterocolitica, Vibrio cholerae, and Pseudomonas aeruginosa. None of the 11 LPS preparations was recognized by the eight antisera, but antisera to each of the Campylobacter strains recognized core determinants of some LPS preparations. Antiserum directed against the most serum-sensitive C. jejuni strain, 79-193, was the only antiserum sample that recognized core regions of the rough Salmonella mutants. In converse experiments, when LPS preparations from five Campylobacter strains were blotted with antiserum to Salmonella lipid A, recognition of core structures of each was shown; data from an enzyme-linked immunosorbent assay confirmed this result. In contrast, antiserum to Salmonella typhimurium Re LPS showed no reactivity. We conclude that LPS of Campylobacter strains share lipid A antigenic determinants with the core region of LPS of several other gram-negative organisms.
Granulocyte-macrophage colony-stimulating factor produced by splenic T lymphocytes of mice infected with Schistosoma japonicum
Authors: Owhashi M , Nawa Y
Published: January 2020

The production of granulocyte-macrophage (GM) colony-stimulating factor (CSF) by splenic lymphocytes was examined in murine schistosomiasis japonica. When splenic lymphocytes obtained at various weeks after infection were cultured with soluble egg antigen, GM-CSF activity in the conditioned medium became detectable at 3 weeks after infection, reached a peak at week 5, and persisted at least up to week 7. Not only soluble egg antigen but also concanavalin A was highly effective in stimulating splenic lymphocytes to produce GM-CSF. When splenic lymphocytes were treated with anti-Thy-1.2 antibody and complement, GM-CSF-producing activity was completely abolished. The molecular weight of this T-cell-derived GM-CSF was estimated to be 30,000 by gel filtration on Sephadex G-150. After isoelectric focusing, GM-CSF activity was detected as two major peaks at pH 3.7 and 5.5. The physicochemical nature of this T-cell-derived GM-CSF was compared with those of known lymphokine GM-CSFs or with that of a previously reported GM-CSF in the serum of S. japonicum-infected mice (M. Owhashi and Y. Nawa, Infect. Immun. 49: 533-537, 1985).
Reversal of the biological activity of Escherichia coli heat-stable enterotoxin by disulfide-reducing agents
Authors: ElDeib M M , Dove C R , Parker C D , Veum T L , Zinn G M , White A A
Published: January 2020

Various disulfide-reducing agents, mostly thiols and thiol precursors, were examined for their ability to reduce the disulfide bonds in the Escherichia coli heat-stable enterotoxin STa; reduction of the bonds results in loss of biological activity. The biological activity measured was the stimulation of guanylate cyclase in pig intestinal brush border membranes by STa. Nearly all of the compounds inactivated STa, although at different rates; a smaller number appreciably decreased guanylate cyclase activity when they were introduced into the reaction mixture after STa bound to its receptor. With dithiothreitol, the decrease in reaction rate was both time and concentration dependent and resulted in a reversal to basal activity. The anionic thiols were relatively ineffective in reversing activation, the neutral monothiols were moderately effective, and the aminothiols and neutral dithiols were the most effective. The order of effectiveness of the compounds was S-2-(3-aminopropylamino)ethanethiol greater than 2,3-dimercaptopropanol = 2-aminoethylisothiuronium bromide greater than dithiothreitol greater than 2-mercaptoethylamine greater than alpha-thioglycerol. These compounds were used in weanling pig ligated-intestinal-loop bioassays to determine if STa-induced secretion was reduced when they were injected 20 min after the STa. Instead of S-2-(3-aminopropylamino)ethanethiol we used the phosphorylated derivative S-2-(3-aminopropylamino)ethylphosphorothioic acid; this compound and 2,3-dimercaptopropanol were the only compounds that reduced STa-induced secretion and had no direct secretory or pathological effects.
Salivary immunoglobulin A and serum antibodies to Streptococcus mutans ribosomal preparations in dental caries-free and caries-susceptible human subjects
Authors: Gregory R L , Filler S J , Michalek S M , McGhee J R
Published: January 2020

Caries-free subjects or individuals with low caries susceptibility exhibited significantly higher (P less than 0.001) levels of naturally occurring salivary immunoglobulin A (IgA) and serum IgG, IgA, and IgM antibodies to a Streptococcus mutans ribosomal preparation than subjects with high caries susceptibility. Absorption of saliva and serum samples with S. mutans ribosomal preparations, but not with other S. mutans antigens or with Escherichia coli and Neisseria gonorrhoeae ribosomal preparations, removed the antibody activity. Absorption with Streptococcus sanguis ribosomes and NH4Cl-washed S. mutans ribosomes partially removed the anti-S. mutans ribosome antibody activity. These results provide evidence that naturally occurring salivary and serum antibodies to the S. mutans ribosomal preparation correlate with susceptibility to dental caries.
Distribution of an antigenically related iron-regulated protein among the Neisseria spp
Authors: Mietzner T A , Barnes R C , JeanLouis Y A , Shafer W M , Morse S A
Published: January 2020

Several iron-regulated proteins of Neisseria gonorrhoeae have been reported. One of these, a 37,000-molecular-weight protein (37K protein), appears to be common to all gonococcal isolates. Recently, the occurrence of a similar protein has also been noted in N. meningitidis. The gonococcal 37K protein has been purified and used to produce both rabbit monospecific antiserum and murine monoclonal antibodies. Using these antibody reagents, we analyzed 57 strains from nine species of Neisseria and the closely related organism Branhamella catarrhalis for the presence of proteins antigenically related to the gonococcal 37K protein. Strains grown on medium with low iron content were probed for antigenic reactivity by Western blot techniques and an enzyme-linked immunosorbent assay. Proteins which cross-reacted with the rabbit monospecific antiserum were designated as AgR-37K proteins. The data indicated that the AgR-37K proteins were conserved among the 40 strains of N. gonorrhoeae, N. meningitidis, N. lactamica, and N. cinerea tested. Seventeen strains from other species of Neisseria and Branhamella did not express AgR-37K proteins with the exception of one N. subflava isolate. All AgR-37K proteins appeared to be regulated by the amount of available iron in the growth medium. Murine monoclonal antibodies were used to probe the antigenic heterogeneity of the AgR-37K proteins from different Neisseria spp. Two of seven monoclonal antibodies were broadly cross-reactive, recognizing the AgR-37K proteins from all species examined. The remaining five monoclonal antibodies were more discriminating, recognizing the AgR-37K proteins from certain species. The antigenic conservation of these AgR-37K proteins, particularly among the pathogenic members of the genus Neisseria, may imply that these proteins serve a common function in pathogenicity.
Antimicrobial activity of various immunomodulators: independence from normal levels of circulating monocytes and natural killer cells
Authors: Morahan P S , Dempsey W L , Volkman A , Connor J
Published: January 2020

The effects of 89Sr treatment on the natural host resistance of CD-1 mice and the enhancement of resistance by immunomodulators to infection with Listeria monocytogenes or herpes simplex virus type 2 (HSV-2) were determined. In the CD-1 mouse, single-dose treatment with 89Sr caused a profound decrease in the number of circulating monocytes (Mo), lymphocytes, and polymorphonuclear leukocytes (PMN) within 1 week. There was also marked functional impairment of the Mo inflammatory response, as well as markedly decreased spontaneous and activatable cytotoxicity by splenic natural killer (NK) cells. Despite this profound cellular suppression, there was no significant change in natural resistance of CD-1 mice to L. monocytogenes or HSV-2 infection. Furthermore, prophylactic treatment of mice with the biologic immunomodulator Corynebacterium parvum or the synthetic immunomodulators maleic anhydride-divinyl ether or avridine in liposomes resulted in comparable enhancement of resistance in 89Sr-treated and normal mice. These data indicate that natural and immunomodulator-enhanced resistance of CD-1 mice to microbial infections do not depend on normal levels of Mo, PMN, or NK cells. The resistance enhancement may rely on activated tissue macrophages (M phi). In contrast to the early changes in circulating leukocytes, the resident peritoneal cell populations were not markedly altered until after day 30. There then was a distinct decline in lymphocytes and a gradual decline in M phi; the change in M phi was apparently due to the lack of an age-related increase in the peritoneal M phi population in 89Sr-treated mice in comparison with a slight increase in resident M phi in normal mice. After CD-1 mice were treated with 89Sr, the number of PMN and the function of NK cells generally recovered by about day 50 and was followed by partial recovery of circulating Mo, unless a second dose of 89Sr was administered.
Isolation, purification, and partial characterization of a lipopolysaccharide from Haemophilus pleuropneumoniae
Authors: Maudsley J R , Kadis S , Mayberry W R
Published: January 2020

Lipopolysaccharide (LPS) from Haemophilus pleuropneumoniae 1536, serotype 2, was isolated and purified by a procedure designed to be equally satisfactory for both smooth- and rough-type LPS. The LPS yield was 53%. Analysis of the preparations revealed that protein, nucleic acid, and cellular phospholipid contamination was negligible (less than 0.1%). Analysis of the sugar content of the LPS by gas-liquid chromatography and colorimetric analysis revealed the presence of rhamnose, mannose, galactose, glucose, heptose, glucosamine, galactosamine, and 3-deoxy-D-manno-2-octulosonic acid. The heptose and glucose contents appeared to be unusually high. The fatty acids of the LPS consisted of a mixture of C14:0 and C16:0 in a ratio of about 4.5:1 (50% of the total) and 3-hydroxy C14:0. When used as a preparatory dose for the dermal Shwartzman reaction, as little as 10 micrograms of the LPS injected intradermally in rabbits produced reddening and swelling. After intravenous injection of a 100-micrograms LPS provoking dose, necrosis was observed at all intradermal injection sites. Limulus amebocyte lysate gelation was observed with an LPS concentration as low as 0.5 ng/ml. A typical biphasic fever response was noted in rabbits injected with as little as 0.25 ng of LPS per kg of body weight.
Release of fibronectin-lipoteichoic acid complexes from group A streptococci with penicillin
Authors: Nealon T J , Beachey E H , Courtney H S , Simpson W A
Published: January 2020

Fibronectin binds to Streptococcus pyogenes, and this binding is inhibited by lipoteichoic acid (LTA). Previous studies have shown that LTA can be released from S. pyogenes by treatment with penicillin. Penicillin released LTA from both S. pyogenes and Staphylococcus aureus; however, the binding of fibronectin correlated with the amount of LTA released only in the case of S. pyogenes. Contrarily, clindamycin decreased the ability of S. aureus to bind fibronectin without affecting the binding of fibronectin to S. pyogenes. Further studies indicated that LTA does not inhibit the binding of fibronectin to S. aureus. Fibronectin bound to S. pyogenes could be released from the cell surface by penicillin. Immunological analysis of the released fibronectin indicated that LTA was the only surface component which could be detected as a soluble complex with the released fibronectin. These studies suggest that LTA plays a central role in the binding of fibronectin to S. pyogenes and is not involved in the binding of fibronectin to S. aureus.
Interaction between heat-stable hemolytic substance from Haemophilus pleuropneumoniae and porcine pulmonary macrophages in vitro
Authors: Kume K , Nakai T , Sawata A
Published: January 2020

Cytocidal and anti-phagocytic effects of the heat-stable hemolytic substance produced in culture supernatant by Haemophilus pleuropneumoniae serotype 2 on porcine pulmonary macrophages (PMP) were investigated in vitro. The substance was partially purified by sucrose density gradient ultracentrifugation, and it seems to be a carbohydrate. The partially purified preparation of the heat-stable carbohydrate with hemolytic activity was used as H. pleuropneumoniae hemolysin throughout this study. Viability of the PMP cells exposed to hemolysin with a hemolytic unit of 32 decreased by about 35% during the first 30-min exposure. The response was hemolysin dose- and exposure time-dependent and was neutralized by the anti-hemolysin antiserum. The PMP cells were found to be the most sensitive to hemolysin among the pulmonary, peritoneal, and peripheral blood macrophages obtained from the same animal. Heat treatment of the hemolytic substance in the culture supernatant at 121 degrees C for 2 h did not significantly (P greater than 0.05) alter the cytocidal and hemolytic activities. Pretreatment of the PMP cells with hemolysin at a sublethal dose significantly (P less than 0.01) reduced their phagocytic abilities. Thus, the heat-stable carbohydrate H. pleuropneumoniae hemolysin appears to possess the potential for both cytocidal and antiphagocytic effects on the PMP cells. Death and impaired phagocytosis of the PMP cells by the hemolysin, if it occurs in vivo, would enhance the chances of survival for an invading H. pleuropneumoniae organism. These findings promote understanding of the pathogenesis of pleuropneumonia caused by H. pleuropneumoniae in swine.
Quantitative comparisons of potentially cariogenic microorganisms cultured from noncarious and carious root and coronal tooth surfaces
Authors: Brown L R , Billings R J , Kaster A G
Published: January 2020

Potentially cariogenic microorganisms cultured from noncarious and carious root and coronal (enamel) surfaces were quantitatively compared in patients 22 to 84 years of age (mean, 52 years). We collected 150 plaque specimens from 26 in situ teeth with initial root lesions and from 25 extracted teeth with advanced root lesions. The frequencies of isolation of Streptococcus mutans, Actinomyces viscosus, and Lactobacillus spp. were, respectively, 94, 72, and 51% at the noncarious root site; 98, 71, and 54% at the root lesion; 84, 61, and 44% at the noncarious enamel site; and 100, 66, and 90% at the enamel lesion. The streptococci made up the largest mean proportion of the total anaerobic cultivable microflora, ranging from 31.2% at the noncarious enamel site to 37.6% at the root lesion, while S. mutans varied between 18% at the noncarious enamel and root surfaces and approximately 24% at both the enamel and root lesions. The proportion of actinomyces ranged from 12.3% at the root lesion to 23.6% at the noncarious root site, while A. viscosus varied from 7.8% at the root lesion to 15.1% at the noncarious root site. The largest mean proportion of lactobacilli (4.2%) was recovered at the enamel lesion site. Proportions of Candida spp. made up less than 0.1% at all sites. Proportions of microorganisms did not differ significantly between noncarious enamel and root sites, but the noncarious coronal and root sites had higher (P less than 0.05) proportions of actinomyces than did the root lesion. Also, enamel lesions had a greater (P less than 0.05) percentage of Lactobacillus spp. than did root lesions. The number of streptococci recovered from the root lesion was greater (P less than 0.01) than the number of actinomyces at the same site. S. mutans was recovered from initial root lesions in greater numbers (P less than 0.001) than were actinomyces and lactobacilli. The number of S. mutans recovered at the initial root lesions was greater (P less than 0.01) than that recovered from the advanced root lesions.
Plasmid-determined cytotoxicity in Yersinia pestis and Yersinia pseudotuberculosis
Authors: Goguen J D , Walker W S , Hatch T P , Yother J
Published: January 2020

Yersinia pestis KIM5 was found to be cytotoxic for the IC21 and P388D1 mouse macrophage cell lines, as well as for resident peritoneal macrophages from C57BL/6 mice. Affected cells phagocytosed KIM5 inefficiently, became spherical, detached readily from culture dishes, and retained 51Cr poorly. The cytotoxic effect was dependent on the presence of the 75-kilobase plasmid pCD1. Because this plasmid also encodes the low calcium response (LCR), three Mu d1 insertion mutants previously shown to be LCR- and of reduced virulence in mice were examined for cytotoxicity; all were found to be atoxic. The insertions in these mutants lie within three distinct LCR loci (lcrB, C, and D). Like LCR, cytotoxicity was expressed only at 37 degrees C. Unlike LCR, it was not influenced by Ca2+ concentration, indicating that the V and W antigens are probably not involved. Yersinia pseudotuberculosis was found to have a similar plasmid-dependent cytotoxicity. Thus, biological activity observed as cytotoxicity in vitro may well be a common feature contributing to virulence of the yersiniae.
Uveitis induction in the rabbit by muramyl dipeptides
Authors: Waters R V , Terrell T G , Jones G H
Published: January 2020

Intraocular inflammation (uveitis) was produced in rabbits by intravenous or subcutaneous treatment with N-acetylmuramyl-L-alanyl-D-isoglutamine and several of its synthetic analogs at doses of greater than or equal to 0.2 mg/kg in saline. A dose-dependent increase in permeability of the ocular blood-aqueous barrier as measured by leakage of protein or fluoresceinated dextran from the serum into the eye was observed from 2 to 14 h after glycopeptide treatment. Peak response occurred at approximately 3 h postdose. The lowest dose found to produce maximal vascular leakage for the most active glycopeptide analogs was 1 mg/kg. The adjuvant-inactive L-L stereoisomer of N-acetylmuramyl-L-alanyl-D-isoglutamine was inactive, even at doses as high as 10 mg/kg. Analogs of N-acetylmuramyl-L-alanyl-D-isoglutamine which were homologous in the lactyl side chain were found to cause less uveitis. Chronic biweekly intravenous treatment of rabbits for 1 month with either N-acetyl-L-alpha-aminobutyryl-D-isoglutamine or its lipophilic 6-O-stearoyl derivative at 1 mg/kg, but not with murabutide, resulted in leukocytic inflammatory lesions unique to the uveal tract of the eye. The uveitis was potentially reversible and occurred with decreased severity as long as 2 months after cessation of chronic treatment. Vascular leakage but not cellular infiltrate in the choroid could be modulated by pharmacologic means. Pyrogenicity but not adjuvanticity correlated with ability of glycopeptides to induce vascular leakage. Several adjuvant-active muramyl dipeptide analogs with minimal ability to cause acute vascular leakage or chronic inflammation in the rabbit eye have been identified.
Effect of guinea pig or monkey colonic mucus on Shigella aggregation and invasion of HeLa cells by Shigella flexneri 1b and 2a
Authors: Dinari G , Hale T L , Washington O , Formal S B
Published: January 2020

The effects of guinea pig and rhesus monkey colonic mucus preparations on Shigella aggregation and invasion of HeLa cell monolayers by Shigella flexneri serotype 1b, 2a, and 5 strains were investigated. Guinea pig mucus caused agglutination of S. flexneri serotype 1b but not of S. flexneri serotype 2a or 5. Guinea pig mucus also inhibited HeLa cell invasion by S. flexneri serotypes 1b and 2a. Monkey mucus neither agglutinated any Shigella strain nor inhibited HeLa cell invasion.
Antibodies to porin antigens of Salmonella typhi induced during typhoid infection in humans
Authors: Calderón I , Lobos S R , Rojas H A , Palomino C , Rodríguez L H , Mora G C
Published: January 2020

Immunoglobulin G (IgG)- and IgM-specific antibody titers against Salmonella typhi Ty2 porins have been measured in 30 paired typhoid sera by enzyme-linked immunosorbent assay. These studies have found that IgG serum titers of acute and convalescent sera were 625 and 5,000 times higher, respectively than the control serum titers. The same typhoid sera were titrated with S. typhi Ty2 flagellin and S. typhi lipopolysaccharide. The titers against these antigens were considerably lower than those against the porins. The highest IgM-specific titer has also been found against porins in convalescent-phase sera. However, the largest increase in IgM-specific titer compared with the control group titer was obtained against flagellin during the acute phase of typhoid. The lowest increases in antibody titer were obtained with the IgM-specific anti-lipopolysaccharide in both types of sera. This may be because many normal individuals in endemic areas already have IgM titers against lipopolysaccharide. This study has provided good evidence that porins are excellent antigens and that IgG-specific antiporin titers may be of diagnostic value in typhoid infections in endemic areas.
Hormonal influence on experimental infections by a toxic shock strain of Staphylococcus aureus
Authors: Best G K , Abney T O , Kling J M , Kirkland J J , Scott D F
Published: January 2020

Subcutaneous infection chambers in rabbits were infected with a strain of Staphylococcus aureus isolated from a patient with toxic shock syndrome. Estrogens (mestranol and 17-beta-estradiol) protected male rabbits and prolonged survival. Neither androgens (testosterone and dihydrotestosterone) nor progesterone affected the susceptibility of intact or ovarihysterectomized female rabbits.
Transposon mutagenesis as a tool to study the role of hemolysin in the virulence of Listeria monocytogenes
Authors: Gaillard J L , Berche P , Sansonetti P
Published: January 2020

The role of hemolysin in the virulence of Listeria monocytogenes was studied by using transposon mutagenesis. The 26-kilobase conjugative transposon Tn1545, originally found in Streptococcus pneumoniae, was transferred to a hemolytic virulent strain of L. monocytogenes. The frequency of transfer was estimated to be about 10(-8) per recipient. This allowed us to isolate a nonhemolytic mutant which most likely harbors a single copy of Tn1545. Loss of hemolysin production was associated with loss of virulence. The 50% lethal dose of the mutant was assessed to about 10(9.6) bacteria per mouse after intravenous challenge. Nonhemolytic bacteria were unable to grow in host tissues and were rapidly eliminated from the spleen and liver of infected mice. Virulence was restored in hemolysin-producing revertant obtained by spontaneous loss of transposon Tn1545. These results strongly suggest that hemolysin is a major virulence factor implicated in the intracellular growth of L. monocytogenes.
Characterization of murine monoclonal antibodies to Escherichia coli J5
Authors: Miner K M , Manyak C L , Williams E , Jackson J , Jewell M , Gammon M T , Ehrenfreund C , Hayes E , Callahan L T , Zweerink H
Published: January 2020

Twenty-eight independently derived monoclonal antibodies (MAb) directed against Escherichia coli J5 endotoxin were produced and characterized. Each MAb exhibited a specific titer by both radioimmunoassay and passive hemagglutination assay. Most of the MAb were of the immunoglobulin G isotype; however, several immunoglobulin M antibodies and one immunoglobulin A antibody were produced. When characterized for their capacity to cross-react with purified endotoxin preparations from several gram-negative bacteria, 22 MAb exhibited no cross-reactivity; 6 demonstrated a limited capacity to cross-react with other endotoxin preparations. When characterized for their capacity to react with the intact organism instead of the purified endotoxin the pattern of cross-reactivity was quite different. Most of the MAb were able to react with Salmonella minnesota Re595. Eighteen were able to react with E. coli O111:B4 (the parent strain of E. coli J5), 13 MAb reacted weakly with Pseudomonas aeruginosa, and 3 reacted weakly with Klebsiella pneumonia. The data imply that MAb generated against E. coli J5 endotoxin demonstrate greater cross-reactivity when assayed against the whole bacterium than when assayed against the corresponding purified endotoxin. We were unable to demonstrate that any of the 28 MAb could passively protect mice against lethal endotoxin challenge.
Comparison of in vivo degradation of 125I-labeled peptidoglycan-polysaccharide fragments from group A and group D streptococci
Authors: Stimpson S A , Esser R E , Cromartie W J , Schwab J H
Published: January 2020

The in vivo degradation and persistence of 125I-labeled peptidoglycan-polysaccharide (PG-PS) fragments from the cell walls of group A and D streptococci were compared by group after intraperitoneal injection into rats. The quantity of PG-PS in the livers and spleens of group D PG-PS-injected rats was less than the quantity in rats injected with group A PG-PS throughout the course of the experiment. Gel filtration analyses of liver and spleen homogenates indicated that group A PG-PS was relatively resistant to degradation, whereas group D PG-PS was extensively degraded to yield a heterogeneous mixture of fragments of lower molecular weight. There was no significant difference in the content of group A PG-PS versus that of group D in joints or blood samples. Analysis of fragment sizes in these tissues also indicated more extensive degradation of group D PG-PS. However, the majority of group A PG-PS in blood samples and joints was a lower molecular weight than that found in the livers or spleens. We conclude that group A PG-PS undergoes a significant but low level of degradation and that group D PG-PS is much less persistent and more extensively degraded than group A PG-PS is in vivo. These differences in PG-PS catabolism may account, in part, for the capacity of group A PG-PS to induce chronic, recurrent arthritis of longer duration than that induced by group D PG-PS.
Outer membrane protein profiles of Haemophilus pleuropneumoniae
Authors: Rapp V J , Munson R S , Ross R F
Published: January 2020

Outer membrane protein profiles of Haemophilus pleuropneumoniae were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Cells were disrupted by sonication, and outer membrane-enriched fractions were prepared by differential centrifugation and selective solubilization of the inner membrane with sodium N-lauroyl sarcosinate. Colony type, growth medium, time of harvest, and in vitro or in vivo passage had no appreciable effect on the protein profiles of the strains examined. Seven patterns were distinguished among the reference strains of the nine capsular serotypes. These patterns were based on the mobility of the major outer membrane proteins migrating in the 39,000- to 44,000-molecular-weight region of the gel, a 16K to 16.5K protein, and a heat-modifiable 29K protein. Strains of serotypes 1 and 9 had identical outer membrane protein profiles, as did strains of serotypes 2 and 6. The reference strains of the remaining five serotypes each had a distinct pattern. The outer membrane protein profiles of 95 field isolates belonging to serotypes 1, 5, 7, and 9 from swine in the midwestern United States were determined and compared with the reference patterns. The results indicate that the population of H. pleuropneumoniae is clonal, with three predominant clones distinguished by both serotype and outer membrane protein profile responsible for the majority of H. pleuropneumoniae disease occurring in swine in the United States.
Molecular studies of Pseudomonas exotoxin A gene
Authors: Vasil M L , Chamberlain C , Grant C C
Published: January 2020

A 2.7-kilobase DNA fragment carrying the entire exotoxin A (ETA) structural gene was divided into three nonoverlapping probes. Two probes covering the ETA structural gene were used in colony hybridization experiments to determine whether sequences homologous to the ETA gene could be detected in genera other than Pseudomonas or in Pseudomonas species other than Pseudomonas aeruginosa. The majority of strains examined other than the P. aeruginosa strains failed to react in the colony hybridization assays. Some Pseudomonas spp. other than P. aeruginosa and some Bordetella spp. did react in colony hybridization assays with the probes. However, additional studies in which we used Southern hybridization methods indicated that these reactions were apparently nonspecific and that the ETA gene is limited to P. aeruginosa. Studies in which we used all three ETA-related probes in Southern hybridization experiments to analyze the ETA gene and surrounding sequences in P. aeruginosa strains isolated from diverse sources revealed the following: (i) the incidence of the ETA gene in P. aeruginosa is approximately equal to 95%; (ii) there are strains which have been isolated from human infections that do not carry the ETA structural gene; (iii) there is a maximum of one copy of the ETA gene per genome in any given strain; (iv) sequences within and 4 to 5 kilobases downstream of the ETA structural gene appear to be well conserved in different strains of P. aeruginosa; and (v) in contrast, sequences immediately upstream of the ETA structural gene are considerably rearranged from strain to strain. A multicopy plasmid carrying the entire cloned ETA gene was transferred to a tox- P. aeruginosa strain. This strain synthesized and secreted mature, full-length ETA, but the amount produced was small considering the multicopy nature of the plasmid. Synthesis of toxin in this strain was only minimally affected by iron. Our data suggest that the synthesis of ETA is positively regulated. Finally, we found that the presence of the ETA gene is independent of the ability of P. aeruginosa to produce several other recognized virulence factors, supporting the concept of the multifactorial nature of P. aeruginosa virulence.
Monoclonal antibody to Streptococcus mutans type e cell wall polysaccharide antigen
Authors: Kato H , Ota F , Fukui K , Yagawa K
Published: January 2020

A monoclonal antibody against the polysaccharide antigen of Streptococcus mutans serotype e was prepared. It was found that beta-methyl-D-glucopyranoside and cellobiose markedly inhibited the precipitin reaction, whereas maltose showed no inhibition. The beta-glucosyl moiety of the type e polysaccharide seems to be the predominant antigenic determinant of the antigen.
Electrophoretic and serological characterization of the lipopolysaccharides of Legionella pneumophila
Authors: Nolte F S , Conlin C A , Motley M A
Published: January 2020

Lipopolysaccharide (LPS) is a major constituent of the outer membrane of gram-negative bacteria. We used sodium dodecyl sulfate-polyacrylamide gel electrophoresis of proteinase-K-digested cell lysates to provide preliminary data on the LPS chemotypes for 20 strains of Legionella pneumophila (serogroups 1 to 8). The profiles of all strains except Chicago 2 (serogroup 6) were similar in the number, spacing, and size distribution of the bands visualized on silver-stained gels and were indicative of smooth LPS. However, compared with the bands from Salmonella minnesota smooth LPS, their banding pattern was much tighter, with three to four legionella bands for every salmonella band. The proteinase K digest of Chicago 2 was unique in that only two widely separated silver-stained bands were seen. LPS profiles of 10 serogroup 1 strains were identical, and the profile of Knoxville 1 was not altered by extensive in vitro passage. We used immunoblotting to investigate the serological specificities of the LPSs. When a rabbit antiserum prepared against a serogroup 1 strain was used to probe nitrocellulose sheets that bound LPS from strains belonging to eight different serogroups, it recognized only the LPS from the homologous serogroup. Similar results were observed with serogroup 2, 4, and 6 antisera. Our data indicate that L. pneumophila has a smooth-type LPS with an unusual banding pattern and that it is a serogroup-specific antigen.
Susceptibility of Campylobacter jejuni to strain-specific bactericidal activity in sera of infected patients
Authors: Pennie R A , Pearson R D , Barrett L J , Lior H , Guerrant R L
Published: January 2020

Campylobacter jejuni is a common cause of inflammatory enteritis, which in normal hosts is usually self-limited and resolves without antibiotic therapy. C. jejuni bacteremia is very rare. We examined sera for bactericidal activity that might be important in limiting the extent of C. jejuni infection in man. We studied the ability of nonimmune sera and homologous and heterologous immune sera from infected patients to kill different fresh case isolates of C. jejuni in vitro. The reduction of the log10 concentration of viable C. jejuni (log10 killing) by fresh sera from nonimmune donors was only 0.2. Log10 killing by homologous acute sera varied from 0 to 3.8 (mean, 1.8). Convalescent sera showed remarkable log10 killing of only homologous C. jejuni, with values of 2.7 to 4.4 (mean, 3.7). The bactericidal effects of acute and convalescent sera were abrogated by heat and EDTA chelation, indicating mediation by complement. The role of classical complement pathway activation was supported by chelating sera with magnesium EGTA [ethylene glycol-bis(beta-aminoethyl ether)-N, N, N', N'-tetraacetic acid] and by reconstitution experiments with heat-inactivated sera, C2-deficient serum, and purified C2. The requirement of specific antibody for the serum bactericidal effect was indicated by the loss of bactericidal activity when immune sera were absorbed with homologous but not heterologous whole C. jejuni isolates. The presence of specific antibodies was further documented by agglutination of only homologous C. jejuni suspensions by heat-inactivated immune sera. Studies with polymorphonuclear leukocytes suggested that ingestion and killing of two C. jejuni strains were modest and variable in the presence of heat-inactivated homologous serum. In summary, the data document a potent serum bactericidal effect that develops rapidly and specifically during C. jejuni enteritis and may be an important factor in host defense against C. jejuni.
Enhanced resistance against Listeria monocytogenes at an early phase of primary infection in pregnant mice: activation of macrophages during pregnancy
Authors: Watanabe Y , Mitsuyama M , Sano M , Nakano H , Nomoto K
Published: January 2020

We investigated the pregnancy-induced changes in macrophage activity which are important in the expression of host defense against infections. Several macrophage functions were examined by using Listeria monocytogenes. In pregnant mice, prolonged survival and enhanced in vivo elimination of bacteria were observed in the early phase of primary infection. Functions of peritoneal macrophages, including in vitro phagocytosis intracellular killing, glucose consumption, generation of superoxide anion, and intracellular beta-glucuronidase activity were shown to be enhanced in pregnant mice. These findings indicate that pregnancy enhances macrophage functions qualitatively. Possible mechanisms for this enhancement and the significance of macrophage activation for pregnant hosts are discussed.
The use of monoclonal antibodies to analyze the structure of Clostridium botulinum type E derivative toxin
Authors: Kozaki S , Kamata Y , Nagai T , Ogasawara J , Sakaguchi G
Published: January 2020

Six monoclonal antibodies against Clostridium botulinum type E derivative toxin were prepared. Three of the five binding to the heavy chain neutralized the derivative toxin; the other one binding to the light chain did not. Immunoblotting analysis with the monoclonal antibodies showed that the fragment obtained by tryptic digestion consisted of the light chain and part of the heavy chain (H-1 fragment) linked together by a disulfide bond(s) and that the antigenic determinants common between type E and F derivative toxins were located on both the heavy and light chains. The fragment induced by chymotrypsin treatment, like the tryptic fragment, bound to four monoclonal antibodies. The mild tryptic treatment and reduction resulted in separation of the chymotryptic fragment into two smaller fragments corresponding to the light chain and H-1 fragment. These results indicate that H-1 fragment contains the amino-terminal portion of the heavy chain. The monoclonal antibody neutralizing the toxin and probably recognizing the epitope on the carboxyl-terminal portion (H-2 fragment) of the heavy chain effectively competed for binding of 125I-labeled derivative toxin to synaptosomes. Of the two monoclonal antibodies neutralizing the toxin and recognizing the epitopes on H-1 fragment, one partially inhibited binding, but the other did not. This suggests that the binding of 125I-labeled derivative toxin depends mainly on the carboxyl-terminal region of the heavy chain and that interference with binding is not the only means of toxin neutralization.