bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of phenethyl alcohol on Staphylococcus aureus alpha-lysin production
Authors: Lee K Y , Birkbeck T H
Published: January 2020

Phenethyl alcohol, at the maximum concentration which did not inhibit growth (0.3% [vol/vol]), inhibited the production of alpha-lysin and exoproteases but not that of delta-lysin in Staphylococcus aureus Wood 46. The inhibition of alpha-lysin was reversible, and transient accumulation of cell-associated alpha-lysin occurred in the presence of PEA. A precursor of alpha-lysin ca. 3,000 daltons larger than extracellular alpha-lysin was immunologically detected in the sodium dodecyl sulfate extracts of membranes and whole cells of phenethyl alcohol-treated S. aureus cultures. Also, a degraded form of alpha-lysin was detected in membranes prepared from cells lysed by lysostaphin but not in membranes from cells lysed with an X-press.
Decreased protective efficacy of reduced and alkylated human immune serum globulin in experimental infection with Haemophilus influenzae type b
Authors: Schreiber J R , Barrus V A , Siber G R
Published: January 2020

Conventionally prepared immune serum globulin frequently produces severe side effects when administered intravenously. A modified preparation in which 4 to 5 interchain disulfide bonds have been reduced and alkylated has been made for intravenous use. However, reduction and alkylation may affect Fc-mediated functions of immunoglobulin G, particularly its ability to fix complement by the classical pathway. To determine whether reduction and alkylation alters the protective activity of immune serum globulin in vivo we compared it with two less harshly prepared globulins (pH 4 treated or ultrafiltered) in an infant rat model of Haemophilus influenzae b infection. Antibody binding to the capsular and noncapsular components of H. influenzae b and in vitro bactericidal activity were similar in the globulin preparations. Infant rats were treated with various doses of globulins adjusted to provide identical concentrations of anticapsular antibodies as measured by the Farr radioactive antigen binding assay. At high doses of anticapsular antibody (greater than 1,500 ng per pup), all preparations protected well. At marginal doses (750 ng per pup), however, rats given reduced and alkylated globulin had a significantly greater incidence of bacteremia (P less than 0.05), meningitis (P less than 0.01), and death (P less than 0.05) and a higher magnitude of bacteremia (P less than 0.02) than rats who received pH4-treated or ultrafiltered globulins. These differences were not due to differences in anticapsular antibody concentrations achieved in the serum. The 50% protective serum concentrations of anticapsular antibody in this model were 200 to 300 ng/ml for reduced and alkylated globulin and 100 to 200 ng/ml for acid-treated globulin. Absorption of the globulins with purified H. influenzae b capsule reduced in vitro bactericidal activity and rat protective activity. However, the magnitude of bacteremia was lower in rats receiving absorbed pH 4-treated globulin than in those receiving absorbed reduced and alkylated globulin (P less than 0.05). We conclude that reduced and alkylated immunoglobulin G provides significantly less protective activity against H. influenzae b infection in this model than globulins not so modified, and we suggest that the altered Fc function of the immunoglobulin G, such as the decreased ability to fix complement by the classical pathway or decreased Fc-mediated opsonization, may be responsible for this impairment.
Expression of antigens encoded by the virulence plasmid of Yersinia enterocolitica under different growth conditions
Authors: Skurnik M
Published: January 2020

The expression of polypeptides of the virulence plasmid of Yersinia enterocolitica serotype O:3 was studied with the immunoblotting technique and specifically absorbed antisera to Y. enterocolitica O:3. At least 16 polypeptides were apparently specified by the virulence plasmid when plasmid-bearing bacterial were grown at 37 degrees C or intraperitoneally in semipermeable capsules. The different growth media used (also with added Ca2+) had quantitatively or qualitatively only a little influence on the expression of these polypeptides, whereas the growth temperature had a stronger influence. The best expression was achieved at 37 degrees C, at 22 degrees C the expression was weak, and at 4 degrees C the plasmid genes were inactive. Two chromosomally encoded polypeptides were expressed only at 37 degrees C, whereas the expression of eight polypeptides expressed at 22 degrees C was repressed at 37 degrees C. The intraperitoneal growth in capsules was used to detect the virulence plasmid-associated polypeptides of Yersinia pestis. Four plasmid-associated polypeptides were detected in Y. pestis with antiserum to Y. enterocolitica virulence plasmid antigens, and three were detected with antiserum to Y. pestis EV76. These results suggested that the virulence plasmid of Y. pestis was activated in the interstitial environment in vivo, where Ca2+ concentration was high, and also that the virulence plasmids of Y. enterocolitica and Y. pestis have three to four immunologically related polypeptides in common.
Antigenic evidence for host origin of exudative fluids in lesions of Treponema pallidum-infected rabbits
Authors: Wos S M , Wicher K
Published: January 2020

Mucoid fluid accumulating within syphilitic lesions has been considered to be of Treponema pallidum origin. To test this assumption, we examined testicular exudative fluids from T. pallidum-infected rabbits for the presence of T. pallidum antigens by various sensitive immunochemical methods, including Western blot analysis. Antigenic analysis of these fluids revealed host components but not treponemal antigens. Prolonged immunization of rabbits, guinea pigs, and a goat with this material in complete Freund adjuvant elicited low titers (fluorescent-treponemal-antibody test titer, less than or equal to 10) of antitreponemal antibodies in the rabbits and guinea pigs but not in the goat. The data suggest that these mucoid fluids are of host origin. The presence of mucopolysaccharides in these fluids may be related to the infective process. The possible mechanism by which mucopolysaccharides protect T. pallidum from immune mechanisms and its potential relationship to the pathogenesis of the disease are discussed.
Tryptophan content of Clostridium perfringens epsilon toxin
Authors: Sakurai J , Nagahama M
Published: January 2020

The tryptophan content of Clostridium perfringens epsilon toxin was investigated. When the tryptophan content was determined by amino acid analysis after the hydrolysis of epsilon prototoxin with methanesulfonic acid containing 3-(2-aminoethyl)indole and by the spectrophotometric method with N-bromosuccinimide, the number of tryptophan residues was calculated at 1/mol of the protein. Cleavage of the prototoxin or the toxin with N-bromosuccinimide in the presence of urea gave two new fragments on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. There was only a tyrosine residue as the new N-terminal amino acid after the cleavage of the prototoxin or the toxin with N-bromosuccinimide. The data showed that epsilon prototoxin or epsilon toxin contained only one tryptophan residue.
Activation of rat B lymphocytes by Actinobacillus actinomycetemcomitans
Authors: Yoshie H , Taubman M A , Ebersole J L , Olson C L , Smith D J , Pappo J
Published: January 2020

We examined the lymphoproliferative responses of cervical lymphocytes and splenocytes of homozygous (rnu/rnu) congenitally athymic nude and normal heterozygous (rnu/+) Rowett rats to whole cells of Actinobacillus actinomycetemcomitans, a suspected periodontal disease pathogen. Previously sensitized cells from immunized only, infected only, or immunized and infected, normal rats demonstrated proliferation in response to formalinized A. actinomycetemcomitans, but cells from nude rats did not proliferate. The maximum antigenic response was observed at day 5 of culture. A. actinomycetemcomitans caused cervical lymphocytes and splenocytes from untreated naive normal and nude rats to undergo increased DNA synthesis at day 2 of culture. Highly enriched nonsensitized spleen T cells prepared on a nylon wool column did not respond to A. actinomycetemcomitans, whereas enriched nonsensitized B cells proliferated. Differences in response were probably not attributable to contributions from macrophages in the T- or B-cell populations, since macrophage percentages were approximately the same in both preparations. T-cell reconstitution of nude rats with neonatal thymus cells from rnu/+rats resulted in partial recovery of T-cell function but had no effect on the mitogenic response to A. actinomycetemcomitans. It is suggested that the antigenic responses to A. actinomycetemcomitans are dependent on T cells and that A. actinomycetemcomitans cells have mitogenic activity for B cells. The potential importance of these findings in periodontal disease is discussed.
Adherence of Escherichia coli in pathogenesis of endometritis and effects of estradiol examined by scanning electron microscopy
Authors: Nishikawa Y
Published: January 2020

Escherichia coli was inoculated into the uterine lumen of ovariectomized rats, and the endometrial surfaces were examined by scanning electron microscopy. Adherence of E. coli to the epithelium and destruction of the surface leading to purulent endometritis were noticed. When rats were treated previously with estradiol, adherence of E. coli was not detected.
Cloning of the gene for the common pathogenic Neisseria H.8 antigen from Neisseria gonorrhoeae
Authors: Black W J , Cannon J G
Published: January 2020

Neisseria gonorrhoeae DNA that encodes the pathogenic Neisseria H.8 common antigen was cloned in the lambda phage sep6. The recombinant phage, designated s6H.8, was detected immunologically with a monoclonal antibody that binds to the H.8 antigen. The gonococcal and s6H.8 forms of the antigen yielded identical partial proteolysis epitope maps. Neisseria species that did not manifest the H.8 antigen showed little or no DNA homology with s6H.8. This clone should facilitate investigation into the clinical utility of this antigen and determination of its possible function in gonococcal pathogenesis.
Human plasma fibronectin inhibits adherence of Streptococcus pyogenes to hexadecane
Authors: Courtney H S , Ofek I , Simpson W A , Whitnack E , Beachey E H
Published: January 2020

The effect of human plasma fibronectin on the adherence of Streptococcus pyogenes to hexadecane droplets was investigated. Fibronectin blocked the adherence of streptococci to hexadecane in a dose-dependent manner. The inhibitory effect resulted from the binding of fibronectin to the streptococcal cells; radiolabeled fibronectin failed to bind to the hexadecane but bound readily to untreated streptococci. Chemical treatments of streptococci that decreased streptococcal binding of fibronectin also decreased their binding to hexadecane. Pretreatment of fibronectin with lipoteichoic acid blocked the binding of fibronectin to streptococci and abolished its ability to inhibit streptococcal adherence to hexadecane in a dose-related manner. In contrast, wheat germ agglutinin, which binds to N-acetylglucosamine on the surface of S. pyogenes cells, failed to alter hexadecane adherence. The data suggest that fibronectin binds to lipoteichoic acid on the surface of the streptococci, thereby preventing lipoteichoic acid from interacting with the hexadecane phase.
Interaction of Salmonella telaviv with Maclura pomifera lectin
Authors: Allen P Z
Published: January 2020

Salmonella telaviv, Salmonella tranoroa, and Salmonella illinois were examined for their ability to interact with 15 purified lectins of known sugar specificity. The only interaction observed was between the lectin of Maclura pomifera and S. telaviv. M. pomifera lectin specifically agglutinated suspensions of S. telaviv and precipitated with its purified lipopolysaccharide and isolated lipid A free O polysaccharide. Quantitative inhibition assays showing methyl-alpha-D-galactopyranoside and N-acetyl-D-galactosamine to be potent inhibitors of Maclura lectin precipitation by S. telaviv O polysaccharide suggest that the interaction is mediated by D-galactose or N-acetyl-D-galactosamine units of bacterial polysaccharide structure, or both.
Effects of Clostridium difficile toxins given intragastrically to animals
Authors: Lyerly D M , Saum K E , MacDonald D K , Wilkins T D
Published: January 2020

We examined the activities of Clostridium difficile toxin preparations given intragastrically to hamsters, mice, and rats. The culture filtrate from a highly toxigenic strain of C. difficile caused hemorrhage and accumulation of fluid in the small intestine and cecum, diarrhea, and death in hamsters and mice. In rats, the culture filtrate caused only a small amount of fluid accumulation and slight hemorrhage along the small intestine. When toxin A was removed from the culture filtrate, the filtrate lost its activity. Preparations of homogeneous toxin A caused a response similar to that observed after the administration of culture filtrate. Hamsters were more sensitive to toxin A than mice or rats were. When hamsters were given multiple low doses of toxin A 1 week apart at a concentration which singly caused no response, they became ill and died, indicating that the toxin may have long-term effects. High amounts of toxin B did not cause any significant response when given intragastrically, unless initially mixed with low amounts of toxin A or given to hamsters with bruised ceca. These results suggest that toxins A and B act synergistically and that the action of toxin B may occur via the tissue damage caused by toxin A.
Integration of the Vwa plasmid into the chromosome of Yersinia pestis strains harboring F' plasmids of Escherichia coli
Authors: Zsigray R M , Hopper J B , Zukowski K , Chesbro W R
Published: January 2020

Conditional virulent strains of Yersinia pestis were used as recipients of an F-lac plasmid from either Escherichia coli 23.10S or E. coli CSH23. The transconjugants of Y. pestis were calcium independent; however, calcium dependence was restored after the loss of the E. coli plasmid. The plasmid contents of several Y. pestis F-lac clones were compared with those of the parent strains and several lac segregants. Although the 6- and 61-megadalton plasmids were detected in all strains tested, the Vwa plasmid was absent in the F-containing strains. The plasmid was evident, however, in the lac segregants derived from the F-lac clones. Results of Southern transfers indicated that the Vwa plasmid had integrated into the chromosome of Y. pestis strains harboring F-lac.
Molecular cloning and expression of Chlamydia trachomatis major outer membrane protein antigens in Escherichia coli
Authors: Stephens R S , Kuo C C , Newport G , Agabian N
Published: January 2020

DNA obtained from Chlamydia trachomatis (serovar L2) was partially digested with DNase I and inserted into the beta-galactosidase gene of bacteriophage lambda gt11. Seven recombinants were selected that produced immunoreactive fusion proteins which were detected with anti-C. trachomatis rabbit serum. One recombinant, designated lambda gt11/L2/33, reacted with various monoclonal antibodies that recognize species-, subspecies-, and type-specific determinants on the chlamydial major outer membrane protein (MOMP). Immunoblot analysis of a lambda gt11/L2/33 lysogen revealed a fusion protein that expressed a approximately 15,000-dalton carboxyl-terminal peptide of the chlamydial MOMP. This moiety of the MOMP possesses epitopes responsible for each of the unique reactivities demonstrated by anti-MOMP monoclonal antibodies. The lambda gt11/L2/33 recombinant contained a 1.1-kilobase DNA insert which hybridized to DNA isolated from each of the 15 C. trachomatis serovars.
T-cell-mediated immune response in murine malaria: differential effects of antigen-specific Lyt T-cell subsets in recovery from Plasmodium yoelii infection in normal and T-cell-deficient mice
Authors: Brinkmann V , Kaufmann S H , Simon M M
Published: January 2020

For analysis of the role of immune T cells in protective immunity against murine malaria, Plasmodium yoelii-immune Lyt T-cell subsets were functionally characterized in vitro and in vivo. Selected Lyt2- and Lyt2+ T cells from P. yoelii-immune C57BL/10 mice differed in their capability to proliferate in response to P. yoelii antigen in vitro. Only the Lyt2- T-cell population produced T-cell growth factor upon restimulation, and none of the selected T-cell subsets produced detectable amounts of macrophage activating factor. Lyt2- but not Lyt2+ lymphocytes were capable of transferring protection to normal C57BL/10 mice. When transferred into T-cell-deficient C57BL/6-nu/nu mice, adoptive resistance to P. yoelii by Lyt2- lymphocytes was only demonstrable after prior reconstitution of recipients with normal T cells. These results suggest an interaction between P. yoelii-immune Lyt2- T cells and normal T lymphocytes via T-cell growth factor in the development of protective immunity to malaria.
Systemic Coccidioides immitis infection in nude and beige mice
Authors: Clemons K V , Leathers C R , Lee K W
Published: January 2020

The course of experimental systemic Coccidioides immitis infection was assessed quantitatively and histologically in beige mice, congenitally athymic nude mice, and their respective normal counterparts. After intravenous inoculation with 50 arthroconidia, the number of viable C. immitis cultured from the spleens, livers, and lungs progressively increased throughout the assay in the organs of all mice. During the first 2 weeks of infection, significantly greater numbers of CFU were recovered from the spleens and livers, but not the lungs, of nude mice than from the respective organs of their phenotypically normal littermates. Significantly greater numbers of CFU were cultured from the lungs and spleens of beige mice compared with the number recovered from their functionally normal littermates. After intranasal inoculation, extrapulmonary dissemination of C. immitis occurred at an equal rate and resulted in similar organ burdens in nude mice and their normal littermates. Histological examination of infected tissues revealed a characteristic mixed inflammatory cell infiltrate in euthymic mice; the response in nude mice was less severe, consisting predominantly, if not solely, of granulocytes. In addition, in tissue sections from nude mice, but not in those from their euthymic counterparts, mature spherules were frequently observed to be devoid of an associated inflammatory response. The inflammatory lesion in beige mice contained a predominance of mononuclear cells, whereas their littermates responded with a typical mixed granulomatous infiltrate. Collectively, these results provide evidence supporting the hypothesis that resistance to C. immitis infection involves two primary cell populations, one under the direct influence of T-cells and the other independent of T-lymphocytes.
Selective detection of Mycoplasma hyorhinis using cloned genomic DNA fragments
Authors: Taylor M A , Wise K S , McIntosh M A
Published: January 2020

A 13-kilobase DNA fragment from a genomic library of Mycoplasma hyorhinis demonstrated specific Southern hybridization and dot hybridization when tested against a group of different mycoplasmas. This probe selectively recognized M. hyorhinis sequences in purified DNA, broth-grown organisms, and infected cell cultures, providing a direct method for differential detection of this species.
Possible relationship of a 36-megadalton Salmonella enteritidis plasmid to virulence in mice
Authors: Nakamura M , Sato S , Ohya T , Suzuki S , Ikeda S
Published: January 2020

All of the Salmonella enteritidis strains isolated from diseased animals (61 strains) and from beef (2 strains) in Japan and in West Germany (1 strain), except for 2 strains isolated from ducks, harbored either a 36-megadalton (Md) plasmid alone or in combination with several other plasmids of different sizes. It is likely that these 36-Md plasmids from various S. enteritidis strains were derived from the same origin because their plasmid DNAs showed the same cleavage patterns obtained with EcoRI, HindIII, and BamHI. We also suggested that this plasmid is native to S. enteritidis. Tests carried out on two strains isolated from ducks which naturally lacked this plasmid and one strain whose plasmid was artificially cured showed that the strains without the 36-Md plasmid showed less virulence compared to a wild-type strain harboring the 36-Md plasmid, suggesting that this 36-Md plasmid might be associated with virulence for mice.
A comparison of bacterial aggregation induced by saliva, lysozyme, and zinc
Authors: Golub E E , Cheruka J , Boosz B , Davis C , Malamud D
Published: January 2020

Aggregation of bacteria by zinc and lysozyme was studied and compared with aggregation induced by a high-molecular-weight salivary agglutinin. Each ligand was found to exhibit a unique profile of properties when examined by both a microradiochemical centrifugation assay and a turbidimetric assay. Significant differences in rate of aggregation and bacterial species specificity were noted. Zinc- and lysozyme-mediated aggregations were shown to be calcium independent and to proceed rapidly at 0 degree C, in contrast to the salivary agglutinin. Zinc produced large, asymmetric aggregates, saliva produced intermediate-sized aggregates, and lysozyme produced the smallest aggregates. These size differences are consistent with many of the observed reaction properties.
Immunomodulation of the antibody response to lipopolysaccharide in C3H/HeJ mice by complexing with heterologous ribosomes
Authors: Phillips M , Eisenstein T K , Meissler J
Published: January 2020

We show that formaldehyde fixation of Salmonella typhimurium lipopolysaccharide (LPS) to ribosomes purified from Brucella abortus induced a primary immunoglobulin M (IgM) response to LPS in C3H/HeJ mice and upon revaccination resulted in elevated titers of IgM and induction of IgG antibody to the O antigens of LPS, as measured by an enzyme-linked immunosorbent assay. A similar LPS-Aspergillus fumigatus ribosomal complex yielded IgM and IgG antibody to LPS only after secondary stimulation. These results demonstrate that the hyporesponsiveness of C3H/HeJ mice with respect to antibody formation to LPS can be overcome by complexing this molecule to ribosomal particles and provide a theoretical mechanism for the action of some "ribosomal" vaccines. The results are compatible with the hypothesis that LPS in complex with the ribosomes is converted to a T-dependent form of the antigen to which the C3H/HeJ mice can respond.
Role of fibronectin in attachment of Streptococcus pyogenes and Escherichia coli to human cell lines and isolated oral epithelial cells
Authors: Stanislawski L , Simpson W A , Hasty D , Sharon N , Beachey E H , Ofek I
Published: January 2020

We studied the binding of cells of Streptococcus pyogenes and mannose-sensitive Escherichia coli to human fibroblast cell lines and isolated buccal epithelial cells in relation to the cell-associated endogenous or exogenous fibronectin of the host cells. The degree of bacterial binding to cell lines correlated directly with the content of endogenous fibronectin on the surface of the cultured cells, although the correlation was better with S. pyogenes than with E. coli. The addition of exogenous plasma fibronectin to the cell lines or oral epithelial cells enhanced binding of S. pyogenes but suppressed binding of mannose-sensitive E. coli. These findings are consistent with the notion that exogenously acquired fibronectin on the surface of host cells modulates bacterial adherence by providing attachment sites for certain pathogens, such as S. pyogenes, and by blocking receptors for others, such as mannose-sensitive E. coli.
Immunologically reactive proteins of Streptococcus equi
Authors: Timoney J F , Trachman J
Published: January 2020

Immunologically reactive proteins in acid extracts and culture supernatants of Streptococcus equi were recognized through a combination of chromatographic and immunologic procedures. Both high- and low-molecular-weight components of each of these protein preparations were protective for mice and were, therefore, presumed to contain a variety of hydrolytic products or fragments of the M protein of S. equi. Convalescent horse sera that exhibited strong bactericidal activity for S. equi always reacted with polypeptides in the molecular weight range of 24,000 to 29,000, whereas preinfection sera did not. Rabbit antisera to affinity-purified S. equi protein also reacted with these polypeptides, as well as with a polypeptide of about 36,000 to 37,000 molecular weight. M protein in acid extract and culture supernatant did not cross-react in immunodiffusion, but rabbit antiserum to affinity-purified M protein from an acid extract of S. equi reacted strongly with culture supernatant proteins of approximate molecular weights of 67,000, 58,000, and 43,000. We suggest, therefore, that the M protein in culture supernatant is masked by other sequences that are removed by hot acid during preparation of acid extracts. Polypeptides common to acid extracts of S. equi and Streptococcus zooepidemicus were also identified. These polypeptides had molecular weights of about 55,000 and 31,000.
Construction and comparison of recombinant plasmids encoding type 1 fimbriae of members of the family Enterobacteriaceae
Authors: Clegg S , Hull S , Hull R , Pruckler J
Published: January 2020

The genes encoding type 1 fimbriae of Salmonella typhimurium, Enterobacter cloacae, and Serratia marcescens were cloned in Escherichia coli. All transformants possessing recombinant plasmids were shown to be fimbriate and demonstrated mannose-sensitive hemagglutinating activity. A comparison of the physical maps of these plasmids revealed little similarity among them, although plasmids encoding type 1 fimbriae of Escherichia coli and Klebsiella pneumoniae appeared similar with respect to restriction enzyme sites. The fimbrial gene cluster ranged in size from 5.5 to 9.0 kilobase pairs as determined by transposon mutagenesis. Plasmid-containing E. coli strains were shown to produce species-specific fimbrial antigens with little or no cross-reactivity between genera. Therefore, it was presumed that each plasmid contained the gene encoding the fimbrial subunit. Complementation was not detected between nonfimbriate insertion mutants of different species but was seen with mutants of the same species.
Adherence of Entamoeba histolytica trophozoites to rat and human colonic mucosa
Authors: Ravdin J I , John J E , Johnston L I , Innes D J , Guerrant R L
Published: January 2020

We studied the adherence of [3H]thymidine-labeled axenic Entamoeba histolytica (strain HM1-IMSS) to in vitro preparations of rat and human colonic mucosa. Studies were performed with fixed or unfixed rat colonic mucosa, unfixed rat mucosa exposed to trypsin, unfixed rat submucosa, and fixed human colonic mucosa. Twenty percent of the amebae adhered to fixed rat colonic mucosa; adherence was specifically inhibited by N-acetyl-D-galactosamine (GalNAc), galactose, and asialofetuin. The adherence of amebae to fixed human colonic mucosa was also GalNAc inhibitable. Greater adherence was found with unfixed rat colonic mucosa (40.9%) and was not GalNAc inhibitable unless the tissue was first exposed to trypsin. However, GalNAc did inhibit the adherence of amebae to unfixed rat submucosa. Glutaraldehyde fixation of amebae inactivates known amebic adhesion proteins; there was a markedly decreased adherence of fixed amebae to trypsin-exposed mucosa or fixed rat colonic mucosa. However, fixed or viable amebae had equal levels of adherence to unfixed rat colonic mucosa, suggesting the presence of a host adhesion protein that binds to receptors on amebae. Human (10%) and rabbit (5%) immune sera reduced the adherence of viable amebae to fixed rat colonic mucosa. We concluded that the GalNAc-inhibitable adhesion protein on the surface of E. histolytica trophozoites mediated adherence to fixed rat mucosa, fixed human colonic mucosa, trypsin-exposed unfixed rat mucosa, and unfixed rat submucosa. The surface of unfixed rat colonic mucosa contained a glutaraldehyde- and trypsin-sensitive host adhesion protein, perhaps in the overlying mucus blanket, which bound viable or fixed E. histolytica trophozoites.
Effect of genetic modification of antibody responsiveness on resistance to Toxoplasma gondii infection
Authors: Siqueira M , Drumond L S , Gennari M , Ferreira V C , Reis M H , Biozzi G
Published: January 2020

Resistance to Toxoplasma gondii infection was studied in the high (H/f) and low (L/f) antibody responder lines of mice that were selected on the basis of quantitative antibody responsiveness to the flagellar antigen of Salmonella (selection III). No interline difference was observed in resistance to a highly virulent strain of T. gondii. In contrast, H/f mice were much more resistant than L/f mice to a moderately virulent strain of T. gondii: a 5000-fold difference in terms of the 50% lethal dose was found. The degree of resistance in (H/f X L/f)F1 hybrids was intermediate compared with that in parental lines for both mortality and survival time. The antibody titers to Toxoplasma antigens measured during the course of the infection were significantly higher in H/f than in L/f mice. This interline difference was underestimated because parasite multiplication occurs faster in L/f mice, which increases antigenic stimulation. The stronger resistance of H/f mice is probably due to their higher capacity of antibody production in the course of infection.
Partial amino acid sequence and molecular cloning of the encoding gene for the major outer membrane protein of Chlamydia trachomatis
Authors: Nano F E , Barstad P A , Mayer L W , Coligan J E , Caldwell H D
Published: January 2020

The first 25 N-terminal amino acids of the major outer membrane protein of Chlamydia trachomatis serovar L2 were determined. The amino acid sequence was used to construct an oligonucleotide probe specific for the major outer membrane protein gene. Using this oligonucleotide as a hybridization major outer membrane protein gene. Using this oligonucleotide as a hybridization probe, we discovered one recombinant clone that produced a 15-kilodalton polypeptide which reacted with a monoclonal antibody directed against the major outer membrane protein type-specific epitope. In a separate set of experiments, we uncovered another recombinant clone that produced a 51-kilodalton polypeptide which was reactive with an anti-major outer membrane protein subspecies-specific monoclonal antibody. The expression of these recombinant DNA plasmids in Escherichia coli is discussed.
Purification and characterization of fimbriae isolated from Bordetella pertussis
Authors: Zhang J M , Cowell J L , Steven A C , Carter P H , McGrath P P , Manclark C R
Published: January 2020

Fimbriae were detached from Bordetella pertussis by mechanical shearing and purified by successive precipitations with ammonium sulfate, phosphate buffer (pH 6.0), and magnesium chloride. In each of these purification steps, the fimbriae aggregated into bundles as seen by electron microscopy. These aggregates could be disaggregated at pH 9.5. By electron microscopy, the purified fimbriae appeared as long filaments with a diameter of 5 nm. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified fimbriae showed a single protein subunit with a molecular weight of 22,000. The purified fimbriae did not have hemagglutinating activity when assayed with several types of erythrocytes, and they were antigenically, chemically, and structurally distinct from the filamentous hemagglutinin of B. pertussis. The purified fimbriae were also identified as serotype 2 agglutinogens, since antibody to the purified fimbriae agglutinated B. pertussis strains serotyped as 1.2.4, 1.2.3, or 1.2.3.6 but did not agglutinate those serotyped as 1.3.6.
Individual evolution of digestive tract colonization of holoxenic mice by Candida albicans
Authors: Walbaum S , Dujardin L
Published: January 2020

Oral administration of various concentrations of Candida albicans to 6-day-old mice established colonization of the digestive tract without mortality. After being weaned (day 21), the development of colonization was studied in a group of mice by daily counting of the number of CFU contained in the feces of each animal. Two features concerning the development of colonization were noted. The course of colonization in individual mice was highly erratic and lead to either transitory or sometimes long-lasting colonization. These results show the importance of a dynamic study of colonization, a condition necessary for any experimental study.
Comparative bacteriology of juvenile periodontitis
Authors: Moore W E , Holdeman L V , Cato E P , Smibert R M , Burmeister J A , Palcanis K G , Ranney R R
Published: January 2020

Statistical comparisons of the floras associated with juvenile periodontitis, severe periodontitis, and moderate periodontitis indicated that differences in the bacterial compositions of affected sites in these populations were not statistically significant. The subgingival flora of affected juvenile periodontitis sites was statistically significantly different from the adjacent supragingival flora and from the subgingival floras of people with healthy gingiva and of children with developing (experimental) gingivitis. However, the subgingival flora of affected juvenile periodontitis sites was not significantly different from the flora of sites with gingival index scores of 1 or 2 in adults with developing (experimental) gingivitis. Of 357 bacterial taxa among over 18,000 isolates, 54 non-treponemal species, 2 treponemal species, and mycoplasma were most associated with diseased periodontal sulci. These species comprised an increasing proportion of the flora during developing gingivitis and constituted over half of the cultivable flora of diseased sites.
Microbial ecology of plaque in rats with naturally occurring gingivitis
Authors: Isogai E , Isogai H , Sawada H , Kaneko H , Ito N
Published: January 2020

The microbial ecology of adherent plaque was investigated in relation to the pathological findings of gingivitis in plaque-susceptible rats. Plaque developed in the gingiva of the lower incisor in plaque-susceptible rats, but not in plaque-resistant rats, after they were fed a commercial powder diet. With increase in plaque volume, the total counts of bacteria increased 10(9) to 10(11)/g. In the first 3 months, Bacteroides species increased and became the predominant population. Streptococcus species also increased at the same time. After 9 months, Fusobacterium species and oral Treponema species were recognized in increasing numbers. The anaerobic bacteria increased in proportion with the progression of plaque development. Bacteroides intermedius, Fusobacterium nucleatum, Streptococcus salivarius, and other species were isolated. Acute gingivitis was observed within 3 months, and subacute-chronic gingivitis was observed between 2 and 12 months. These findings suggest that proportional changes in the gingival plaque flora may uniquely contribute to the development of gingival inflammation in this experimental model.
Toxicity of group B Streptococcus agalactiae in adult rats
Authors: Warejcka D J , Goodrum K J , Spitznagel J K
Published: January 2020

Several strains of group B Streptococcus agalactiae were found to be lethal for young adult rats. When bacteria were heat killed and then injected intraperitoneally into rats, rapid death (14 to 18 h) of the rats occurred, characterized by labored breathing, hemolyzed serum, hemoglobinuria, and subungual hemorrhages. Sections of tissues from these rats failed to reveal the cause of death. Rats injected with toxic or nontoxic strains of group B S. agalactiae had reduced numbers of circulating leukocytes and low serum C3 levels in comparison with those in control rats. The toxic strains of group B S. agalactiae induced dramatic decreases in platelet numbers, and in plasma fibrinogen levels as well, suggesting that the toxicity was due to disruption of the coagulation system. Rapid death in the absence of infection suggests that group B S. agalactiae may have a cell-associated toxin that induces these changes. Such a toxin may be a contributory factor in the high mortality rate associated with group B streptococcal infections of the human neonate.
Lack of antibacterial activity after intravenous hydrogen peroxide infusion in experimental Escherichia coli sepsis
Authors: Shenep J L , Stokes D C , Hughes W T
Published: January 2020

The intravenous administration of hydrogen peroxide has been reported to benefit patients with pneumonia and to reduce Plasmodium parasitemia in experimentally infected mice. We assessed the antibacterial activity of intravenously infused hydrogen peroxide against hydrogen peroxide-susceptible Escherichia coli (MBC of hydrogen peroxide, 0.23 mM) in experimentally infected rabbits. No decrease in the level of bacteremia was detected at the maximum intravenous infusion rate of hydrogen peroxide physiologically tolerated by the rabbits (2.0 mumol/h). Moreover, the addition ex vivo of greater amounts of hydrogen peroxide to human or murine blood containing E. coli resulted in no detectable antibacterial action. In contrast, ethyl hydrogen peroxide, which is not affected by catalase, was bactericidal when added ex vivo to human blood containing E. coli. These results suggest that extracellular hydrogen peroxide, whether of exogenous or endogenous origin, does not have antibacterial activity in the blood of animals having even low levels of catalase.
Vaccination of rabbits against Entamoeba histolytica with aqueous suspensions of trehalose-dimycolate as the adjuvant
Authors: Sharma A , Haq A , Ahmad S , Lederer E
Published: January 2020

Rabbits were immunized with soluble Entamoeba histolytica antigen with an aqueous suspension of trehalose-6,6'-dimycolate used as the adjuvant. Induction of protective immunity in the immunized animals was demonstrated by enhanced humoral and cell-mediated immune responses and 100% survival after challenge. Administration of soluble antigen only failed to induce a similar degree of protective immunity. Trehalose-6,6'-dimycolate alone produced only a slight increase in nonspecific resistance.
Suppressive effect of secondary Toxoplasma gondii infection on antibody responses in mice
Authors: Suzuki Y , Kobayashi A
Published: January 2020

The effect of the secondary infection with Toxoplasma gondii on antibody responses to unrelated antigens was examined in mice. A reinfection with 5 X 10(3) organisms did not affect either primary anti-sheep erythrocyte antibody responses, or anti-dinitrophenol antibody responses to dinitrophenylated keyhole limpet hemocyanin. With an increase of the reinfection dose to 2.5 X 10(4) organisms, suppression of anti-sheep erythrocyte antibody responses was induced. By contrast, in the primary infection, the anti-sheep erythrocyte and anti-dinitrophenol antibody responses were markedly suppressed by an injection with only 5 X 10(2) or 1 X 10(3) T. gondii organisms. Plastic-adherent cells of spleens from mice reinfected with 2.5 X 10(4) organisms showed a strong suppressor activity in an in vitro primary anti-sheep erythrocyte antibody response system. These results demonstrate that a nonspecific suppression of antibody responses is provoked by a secondary T. gondii infection, only when mice receive a large number of organisms in the reinfection, and the suppressed antibody responses seem to be caused by an activation of suppressor cells that adhere to plastic.
Susceptibility of Propionibacterium acnes to killing and degradation by human neutrophils and monocytes in vitro
Authors: Webster G F , Leyden J J , Musson R A , Douglas S D
Published: January 2020

Propionibacterium acnes, the target of inflammation in acne, was tested for its sensitivity to the bactericidal and degradative functions of human polymorphonuclear leukocytes (PMN), monocytes, and their fractions. P. acnes strains were not killed by PMN under any conditions and were variably killed by monocytes in the presence of serum from acne patients. Control strains of Staphylococcus aureus and Micrococcus lysodeicticus were susceptible to both PMN and monocyte killing. P. acnes strains were also not killed by lysozyme, chymotrypsin, H2O2, human serum, PMN granule lysate, and PMN and monocyte cell lysates. The organism was sensitive to the bactericidal activity of myeloperoxidase in acid pH. In addition, P. acnes was shown to be relatively resistant to the degradative action of PMN and monocyte lysates, whereas M. lysodeicticus, S. aureus, and Staphylococcus epidermidis were all degraded to various degrees. The moieties that were liberated from P. acnes by PMN enzymes were predominantly low in molecular weight (1,000 to 25,000) and were consistent with cell wall fragments.
Arachidonic acid facilitates experimental chronic osteomyelitis in rats
Authors: Rissing J P , Buxton T B , Fisher J , Harris R , Shockley R K
Published: January 2020

Arachidonic acid was used as a facilitating agent in experimental rat Staphylococcus aureus osteomyelitis and compared with the more commonly used agent, sodium morrhuate. The injection of arachidonic acid or sodium morrhuate and S. aureus into rat tibiae caused increased quantitative bacterial bone counts, gross bone pathology, roentgenographic changes, and weight loss. The doses required to produce these changes appeared to be lower for arachidonic acid.
Production of fimbrial adhesins K99 and F41 by enterotoxigenic Escherichia coli as a function of growth-rate domain
Authors: van Verseveld H W , Bakker P , van der Woude T , Terleth C , de Graaf F K
Published: January 2020

The production of fimbrial adhesins K99 and F41 by enterotoxigenic Escherichia coli has been measured in steady-state chemostat experiments at various specific growth rates (microseconds) and in a recycling fermentor across a range of mu values falling to less than 0.004 h-1. It has been demonstrated that the production of K99 and F41 fimbriae is correlated with mu both in aerobic and anaerobic chemostat experiments. A significant production of fimbriae was only detected at mu values higher than 0.2 h-1. This behavior was further examined by culturing the bacteria in a recycling fermentor with complete biomass retention. It could be shown that the production of K99 and F41 fimbriae only occurred during balanced growth, with a high biomass yield at mu values higher than 0.04 h-1 corresponding to mass doubling times (td) of less than 17 h. The production of both fimbriae halted during balanced growth with a lower biomass yield (at mu values between 0.012 and 0.04 h-1 corresponding to td values between 17 and 58 h) and unbalanced stringent growth (at mu values lower than 0.012 h-1 or td values higher than 58 h). The external pH of the medium greatly influenced the production of both K99 and F41 fimbriae. At pH values lower than 7, the production of fimbriae was strongly inhibited. Also, at pH values higher than 7, a decrease in production was observed. The consequences of the observed phenomena for the pathogenic behavior of this E. coli strain are discussed.
Synthetic lipid A with endotoxic and related biological activities comparable to those of a natural lipid A from an Escherichia coli re-mutant
Authors: Kotani S , Takada H , Tsujimoto M , Ogawa T , Takahashi I , Ikeda T , Otsuka K , Shimauchi H , Kasai N , Mashimo J
Published: January 2020

A synthetic compound (506), beta (1-6) D-glucosamine disaccharide 1,4'-bisphosphate, which is acylated at 2'-amino and 3'-hydroxyl groups with (R)-3-dodecanoyloxytetradecanoyl and (R)-3-tetradecanoyloxytetradecanoyl groups, respectively, and has (R)-3-hydroxytetradecanoyl groups at 2-amino and 3-hydroxyl groups, exhibited full endotoxic activities identical to or sometimes stronger than those of a reference lipid A from an Escherichia coli Re-mutant (strain F515). Endotoxic activities tested include pyrogenicity and leukopenia-inducing activity in rabbits, body weight-decreasing toxicity in normal mice, lethal toxicity in galactosamine-sensitized mice and chicken embryos, and the preparation and provocation of the local Shwartzman reaction in rabbits. Compound 406, a synthetic counterpart of a biosynthetic precursor of lipid A molecule, showed by contrast only weak activities in all of the above assay systems except for the lethality in galactosamine-loaded mice. This finding strongly suggests that the presence of acyloxyacyl groups at the C-2' and C-3' positions of the disaccharide backbone is one of the most important determinant structures of the lipid A molecule for exhibition of strong biological activities characteristic of lipopolysaccharide and its lipid A moiety. The activities of the corresponding 4'-monophosphate (compound 504) and 1-monophosphate (505) analogs were considerably less than those of the parent molecule 506 and the reference F515 lipid A. Regarding other biological activities, not only compound 506 but also compounds 504, 505, and 406 showed definite activities, sometimes comparable to those of F515 lipid A and other reference natural products. These are the activation of Tachypleus tridentatus amoebocyte clotting enzyme cascade and human complement via the classical pathway, mitogenic and polyclonal B-cell activation of murine splenocytes, stimulation of peritoneal macrophages in a guinea pig, enhancement of migration of human blood polymorphonuclear leukocytes, and induction of a serum factor that is cytostatic and cytocidal to L-929 cells in Mycobacterium bovis BCG-primed mice. Relative potencies of test synthetic compounds depended on the assay systems and varied from one system to another. Dephospho-compound 503 lacked most of the biological activities that were definitely observed with phosphorylated compounds, probably because of its insolubility. This study demonstrates the successful chemical synthesis of an E. coli-type lipid A.
Detection of genes for heat-stable enterotoxin I in Escherichia coli strains isolated in Brazil
Authors: Maas R , Silva R M , Gomes T A , Trabulsi L R , Maas W K
Published: January 2020

Heat-stable enterotoxin I (STI) can be assayed in intestinal loops of pigs and rabbits and in the gut of infant mice. To produce a simpler and more discriminating assay procedure, we used three gene probes corresponding to three forms of STI called STIa, STIb, and STIc. We tested 159 Brazilian isolates, of which 40 were positive in the infant mouse assay. The STIb and STIc probes are similar (93% DNA homology) and are both different from the STIa probe (70% DNA homology). Of 33 strains that were still active for STI 3 years after their isolation, 25 reacted with both the STIb and STIc probes, 4 reacted with the STIc probe only, and 7 reacted strongly with the STIa probe and weakly or not at all with the other probes. Two strains reacted with all three probes. Further analysis showed that each of these two strains contains a small plasmid that reacts with the STIa probe and a large plasmid that reacts with the STIc probe in one strain and weakly with both the STIa and STIc probes in the other strain. It was also shown that the STIa probe reacts with the cloning vehicle pACYC184 used for the cloning of STIc. We conclude that the gene probes used can identify most STI-producing strains and that in cases of positive responses with several probes careful scrutiny is necessary for analysis.