bluuebunny/crossref_metadata_2025 huggingface dataset:
Properties of crude Campylobacter jejuni heat-labile enterotoxin
Authors: Klipstein F A , Engert R F
Published: January 2020

The amount of crude Campylobacter jejuni enterotoxin present in culture products was quantitated by comparing the response of these preparations with that of pure Escherichia coli heat-labile toxin (LT) in the Chinese hamster ovary assay and in enzyme-linked immunosorbent assays that used GM ganglioside or antisera to LT or both. Maximum C. jejuni enterotoxin production was achieved by growth at 42 degrees C for 24 h under agitation in supplemented GC medium. Adding polymyxin separately to either the broth supernatant or the cells enhanced the recovery of toxin; the yield from cell lysates was much lower. The quantity of C. jejuni enterotoxin produced by clinical isolates obtained locally or provided from Mexico varied widely, over a spectrum from none to large amounts; quantitative values for the amount of C. jejuni enterotoxin determined by the Chinese hamster ovary and enzyme-linked immunosorbent assays correlated with the degree of secretory potency of this material in ligated rat ileal loops. The cytotonic activity of C. jejuni enterotoxin in Chinese hamster ovary cells was abolished by heating at 96 degrees C for 10 min and by preincubation either with GM ganglioside or with LT or cholera toxin antisera. The secretory activity of C. jejuni enterotoxin in ligated rat ileal loops was passively neutralized by antiserum to LT, and immunizing rats with either LT or its B subunit significantly (P less than 0.001) reduced fluid response to active challenge with C. jejuni enterotoxin in ligated ileal loops. These observations indicate that strains of C. jejuni vary in their capacity to elaborate a heat-labile enterotoxin that has close immunological homology with LT and cholera toxin.
Pathogenicity of anaerobic gram-positive cocci
Authors: Brook I , Walker R I
Published: January 2020

The pathogenicity of 20 strains of facultative or anaerobic gram-positive cocci (AGPC) was investigated by injecting them alone or mixed with other flora into mice, utilizing the subcutaneous abscess model. Abscesses induced by a mixture of two organisms were uniformly larger than those induced by single organisms. The relationships among seven AGPC strains, eight aerobes, and two Bacteroides spp. were determined by treating the infected animals with antibiotics and observing the effect of therapy directed against one or both organisms present in the abscess. A total of 70 different combinations were tested. As judged by their responses to antimicrobial therapy, facultative cocci or AGPC were relatively more important than the other species in 6 combinations, equally important in 35 combinations, and less important in 29 combinations. The AGPC most often found to be equal to or more important than the other bacteria were Peptococcus magnus, Streptococcus constellatus, and Peptostreptococcus anaerobius. Proteus mirabilis, Escherichia coli, and Staphylococcus aureus were frequently found to be of more importance than the AGPC.
Phenotypic distinctiveness of Staphylococcus aureus strains associated with toxic shock syndrome
Authors: Todd J K , Franco-Buff A , Lawellin D W , Vasil M L
Published: January 2020

Twenty Staphylococcus aureus strains from patients with toxic shock syndrome (TSS) and 20 from control patients (non-TSS) with infection but no clinical evidence of TSS were compared phenotypically in a collaborative, blinded, randomized study. TSS strains were significantly (P less than 0.05) more likely than non-TSS strains to produce various previously described but related toxic shock-associated proteins (pyrogenic exotoxin C, enterotoxin F, and TSS marker protein), as well as differing in other distinctive phenotypic characteristics, such as hemolysis, bacteriocin susceptibility, arsenate resistance, pigment production, and casein proteolysis. TSS strains were significantly less likely to carry plasmids than control strains. A combination of two variables--proteolysis and toxic shock-associated protein production--statistically accounted for all other phenotypic variations between TSS and non-TSS strains. Only proteolysis covaried with all other significant variables, suggesting a primary role in the phenotypic distinctiveness of TSS S. aureus strains and possibly in the pathogenesis of TSS.
Colonization factors associated with enterotoxigenic Escherichia coli isolated in Thailand
Authors: Changchawalit S , Echeverria P , Taylor D N , Leksomboon U , Tirapat C , Eampokalap B , Rowe B
Published: January 2020

Eighty-six percent (72 of 84) of heat-labile and heat-stable, none of 141 heat-labile, and 24% (27 of 111) heat-stable enterotoxigenic Escherichia coli isolates from Thailand aggregated in less than 1 M (NH4)2SO4, hemagglutinated human group A and bovine erythrocytes in 1% D-mannose, and possessed either colonization factor I or colonization factor II. No other colonization factors were identified by these two methods.
Activated complex of L-cells and Rickettsia prowazekii with N-ethylmaleimide-insensitive phospholipase A
Authors: Winkler H H , Miller E T
Published: January 2020

The interaction of large numbers of viable Rickettsia prowazekii cells with L-cells results in the expression of a phospholipase A activity with the concomitant release of free fatty acids and lysophosphatides from the phospholipids of the L-cell. About 50% of rickettsiae present in the suspension that was centrifuged onto an L-cell monolayer at 0 degree C to effect this interaction formed a tight L-cell-rickettsiae association from which the rickettsiae could not be removed by simple washing. Both the L-cell-rickettsiae association and the rickettsiae before association with L-cells interact with N-ethylmaleimide, so that the subsequent expression of the phospholipase A activity was inhibited (treatment of the L-cells with N-ethylmaleimide before centrifugation does not inhibit phospholipase activity). However, treatment of this association with 2,4-dinitrophenol and KCN caused much less inhibition of this phospholipase A activity than did treatment of the rickettsiae with these agents before centrifugation onto the L-cells. Incubation of the L-cell-rickettsiae association for a short time at 35 degrees C resulted in a very low level of free fatty acid formation and changed this association to an activated complex in which the phospholipase A activity was no longer sensitive to the inhibitory effects of N-ethylmaleimide. The characteristics of the association and activated complex were stable: after a 2-h incubation at 0 degrees C, the association and the activated complex retained both their basal phospholipase A activities and their characteristic responses to N-ethylmaleimide treatment. In scanning electron micrographs of the activated complexes, the rickettsiae that were initially attached were no longer visible after 45 min at 35 degrees C, and the surface of the L-cell appeared to have been etched away. These activated complexes provide a system in which modulators of the phospholipase A can be investigated without the confusion caused by the first-step receptor interaction between rickettsiae and their host cells.
Effect of zinc and phosphate on an antibacterial peptide isolated from lung lavage
Authors: LaForce F M , Boose D S
Published: January 2020

Incubation of Escherichia coli (10(4) organisms per ml) in cell-free rabbit lung lavage for 30 min at 37 degrees C resulted in a 70% reduction in colony counts on deoxycholate agar. A low-molecular-weight peptide (about 3,400 daltons), with zinc as a cofactor, was responsible for this activity. The peptide was isolated by Sephadex G-15 separation of lyophilized rabbit lung lavage which had been centrifuged to remove macrophages and suspended phospholipids and passed through a 10,000-dalton (pore size) membrane filter. Peptide activity against E. coli was inhibited by phosphate buffer but not by borate, Tris, or barbital buffer. Bacteria incubated in phosphate buffer and then washed in saline were resistant to peptide activity. Antibacterial activity was also inhibited when peptide-exposed bacteria were incubated in phosphate buffer before deoxycholate treatment. 32P-radiolabeled E. coli cells lost about 20% of their radiolabel after 15 min of incubation with peptide.
A longitudinal microbiological investigation of Actinobacillus actinomycetemcomitans and Eikenella corrodens in juvenile periodontitis
Authors: Mandell R L
Published: January 2020

Longitudinal clinical and microbiological monitoring of subjects with localized juvenile periodontitis indicated that Actinobacillus actinomycetemcomitans and Eikenella corrodens were significantly associated (P less than 0.05) with active tissue destruction.
Purification and some properties of Aeromonas hydrophila hemolysin
Authors: Asao T , Kinoshita Y , Kozaki S , Uemura T , Sakaguchi G
Published: January 2020

A hemolysin produced by a strain of Aeromonas hydrophila isolated from a patient with diarrhea was purified by acid precipitation and quarternary aminoethyl-Sephadex chromatography. The molecular weight of the hemolysin was estimated at 50,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and at 48,000 by Sephadex G-100 gel filtration. In polyacrylamide gel electrophoresis at pH 4.0 and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the hemolysin migrated as a single band, whereas electrophoresis at pH 9.4 and thin-layer isoelectric focusing demonstrated multiple bands. The results may indicate charge isomers of the hemolysin. The purified hemolysin had a hemolytic activity of 134 hemolytic units per microgram of protein on rabbit erythrocytes. It caused fluid accumulation in infant mouse intestines and rabbit ligated ileal loops. Purified hemolysin also elicited cytotoxicity to Vero cells and lethal toxicity to mice. All these biological activities were lost on heating for 5 min at 56 degrees C. These findings support the notion that A. hydrophila hemolysin is a cytotoxic enterotoxin.
Spontaneous and egg antigen-induced syntheses of immunoglobulin and antibody by spleen cells and hepatic granulomas of mice infected with Schistosoma japonicum
Authors: Stavitsky A B , Garb K S
Published: January 2020

In the absence of egg antigen (SEA), spleen cells from C57BL/6 mice infected for 22 weeks with Schistosoma japonicum were spontaneously induced in vitro to synthesize total immunoglobulin and antibody to SEA. Hepatic granulomas from mice infected for 12 weeks, but not for 22 weeks, also showed spontaneous syntheses of total immunoglobulin and antibody to SEA, but these syntheses were not enhanced upon the addition of SEA. Total immunoglobulin production was enhanced when SEA was added to spleen cells from mice infected for 4 to 7 weeks but not at any other time point.
A cluster of five genes specifying the aerobactin iron uptake system of plasmid ColV-K30
Authors: Carbonetti N H , Williams P H
Published: January 2020

The genetic determinants for the aerobactin iron uptake system of plasmid ColV-K30, cloned as recombinant plasmid pABN1, were mapped by insertional inactivation using Tn1000 (gamma delta). Sites of insertion resulting in loss of aerobactin biosynthesis spanned ca. 5.5 kilobase pairs of cloned ColV-K30 DNA contiguous with a 2-kilobase-pair region in which transposon insertion resulted in loss of the outer membrane ferric-aerobactin receptor protein. Translation products of plasmid pABN1, and of subclones specifying siderophore biosynthesis alone or receptor activity alone, were analyzed by using the maxicell and minicell expression system. Four polypeptides (Mr = 62,000, 35,000, 45,000, and 50,000) are required for biosynthesis of aerobactin. A fifth product (Mr = 74,000) of plasmid pABN1 represents the outer membrane receptor protein. The linear order of genes for these polypeptides was determined by comparing translation products of a series of smaller derivative plasmids and of a number of mutant plasmids carrying Tn1000 at known locations.
Isolation and identification of two hemolytic forms of streptolysin-O
Authors: Bhakdi S , Roth M , Sziegoleit A , Tranum-Jensen J
Published: January 2020

Streptolysin-O was isolated from culture supernatants of group-A beta-hemolytic streptococci (Richards strain) by ammonium sulfate and polyethylene glycol precipitation, DEAE-ion exchange chromatography, preparative isoelectric focusing, and chromatography on Sephacryl S-300. Two forms of the toxin possessing similar hemolytic capacity were identified. The native toxin was a single polypeptide chain devoid of amino sugars with a sedimentation coefficient of 3.9S and a molecular weight of 69,000, and was isoelectric at pH 6.0 to 6.4. Partial degradation of the native toxin occurred during the isolation procedure, yielding a hemolytically active polypeptide with a molecular weight of 57,000 and a pI of 7.0 to 7.5. Both forms of the toxin generated the typical, heterogeneous, open and closed ring-structured channels in erythrocyte membranes. Structural considerations indicated that between 25 and 100 monomer toxin molecules constituted the individual ultrastructurally recognizable channels. Hemolytic titrations indicated that the presence of 70 to 125 toxin molecules per erythrocyte was required to generate an average of one functional lesion per cell. The data are consistent with the concept that one or very few streptolysin-O channels will cause hemolysis.
Lipopolysaccharide hyperreactivity of animals infected with Trypanosoma lewisi or Trypanosoma musculi
Authors: Ferrante A , Carter R F , Ferluga J , Allison A C
Published: January 2020

Rats and mice infected with Trypanosoma lewisi and Trypanosoma musculi, respectively, showed hyperreactivity to lipopolysaccharide (LPS) from gram-negative bacteria. Fatal shock could be precipitated with a dose of LPS 100 to 1,000 times less in infected compared with noninfected animals. In trypanosome-infected rats and mice, extensive liver damage was evident after LPS challenge. These animals showed a pronounced hypoglycemia, marked elevation of blood aspartate transaminase level, and diffuse severe degeneration and total depletion of glycogen in hepatocytes. Only minor changes were observed in noninfected animals given the same dose of LPS. No mononuclear phagocytic cell infiltration was observed in the liver of infected animals. The most striking change was the great increase in size and the probable increase in phagocytic activity and number of sinusoidal Kupffer cells. We suggest that elevated Kupffer cell activity in trypanosome-infected animals may play a role in LPS-induced hepatotoxicity.
Persistence of HLA-B27 cross-reactive bacteria in bowel flora of patients with ankylosing spondylitis
Authors: Prendergast J K , McGuigan L E , Geczy A F , Kwong T S , Edmonds J P
Published: January 2020

Previous studies have shown that antisera raised in rabbits to certain enteric bacteria (cross-reactive bacteria) are capable of specifically lysing in a 51chromium-release lymphocytotoxicity test the lymphocytes of HLA-B27-positive (B27+) patients with ankylosing spondylitis (AS). This study investigated the clinical relevance of this finding by ascertaining whether Escherichia coli isolated from the rectal swabs of 20 B27+ AS patients (B27+ AS+) and 46 controls (35 B27- AS- and 11 B27+ AS-) were able to absorb the lymphocytotoxic activity of these antisera. All isolates from B27+ AS+ patients and one from a B27- AS- individual were capable of removing this activity. These organisms persisted in the bowel flora of five selected patients for at least 9 months. Cross-reactive bacteria were also found in a range of gram-positive organisms, including streptococcal, staphylococcal, and clostridial species. The relevance of these findings is discussed in terms of a pathogenetic concept relating the persistence of cross-reactive bacteria in the bowel flora of B27+ individuals to an early event in the development of AS.
Variation in periodontal floras
Authors: Moore W E , Holdeman L V , Cato E P , Good I J , Smith E P , Ranney R R , Palcanis K G
Published: January 2020

Statistical analyses indicated (i) that the floras of individual samples taken from the depth of sulci with nickel-plated Morse 00 scalers were highly reproducible and representative of the flora present at any given time, (ii) that the different compositions of floras of different people with similar clinical signs were statistically highly significant, and (iii) that floras of different affected sites may differ significantly in some (two of three) people at any one time or may differ from week to week in other people (one of three). Thus the flora composition of individual sites appears to be in dynamic flux, probably in response either to environmental changes or to host responses. There was no evidence that double sampling per se (two single passes with 00 scalers) changed the composition of the flora. Repeat samples taken after 1 week were slightly more similar to the initial samples than were samples taken after 3 weeks.
Location and distribution of a receptor for the 987P pilus of Escherichia coli in small intestines
Authors: Dean E A , Isaacson R E
Published: January 2020

Frozen sections of rabbit or pig small intestines were stained with fluorescein-labeled antibody specific for the 987P receptor isolated from adult rabbit small intestines. The 987P receptor was present along the entire villous surface and in goblet cells in adult rabbits, but only in goblet cells in infant rabbits. In adult rabbits, the receptor was distributed equally in the jejunum and the ileum. Material antigenically similar to the rabbit 987P receptor was demonstrated in goblet cells in neonatal piglet ileum.
In vivo effects of bacterial lipopolysaccharide on proliferation of macrophage colony-forming cells in bone marrow and peripheral lymphoid tissues
Authors: Yokochi T , Nakashima I , Kato N , Miyadai T , Yoshida K , Kimura Y
Published: January 2020

Changes in the number of macrophage colony-forming cells in various tissues of mice injected with lipopolysaccharide (LPS) from Klebsiella pneumoniae, Escherichia coli, or Salmonella enteritidis were studied. The injection of LPS increased macrophage colony-forming cells in peripheral lymphoid tissues such as the spleen, mesenteric lymph nodes, and regional lymph node, although the same treatment caused the decrease of such cells in the bone marrow. This phenomenon was consistently observed when tested by various LPSs. The injection of LPS into mice which had been exposed to X-ray irradiation and reconstituted with syngeneic normal bone marrow cells decreased colony-forming cells in the spleen. The increase of macrophage colony-forming cells in the spleen seemed, therefore, not to be due to migration from the bone marrow. The injection of LPS appeared to shorten the lag time before the initiation of mitosis of colony-forming cells in the spleen but not in the bone marrow. No participation of serum factors in this phenomenon could be detected. It was suggested that there might be an essential difference between the responsiveness to LPS of macrophage colony-forming cells in the spleen and those of the bone marrow.
Purification and characterization of hyaluronidase from oral Peptostreptococcus species
Authors: Tam Y C , Chan E C
Published: January 2020

Hyaluronidase was purified to apparent homogeneity from the spent medium of Peptostreptococcus sp. strain 84H14S. The enzyme was purified 310-fold by ethanol precipitation, gel chromatography, and cation-exchange chromatography with a recovery of 42% of the original activity in the culture medium. The molecular weight of the purified enzyme was estimated to be 160,000 by gel filtration with Sephacryl S-300. Like bacterial mucopolysaccharidases of other sources, the enzyme carried out an eliminative reaction with the substrate, producing 4,5-unsaturated disaccharides as the final end products. Its optimum temperature of activity is 46 degrees C. The purified peptostreptococcal hyaluronidase was different from previously reported bacterial hyaluronidases in several respects. It degraded hyaluronic acid rapidly and also exhibited some activity against chondroitin sulfate A and chondroitin sulfate C. The KmS for hyaluronic acid, chondroitin sulfate A, and chondroitin sulfate C were 0.14, 1.4, and 2.6 mg/ml, respectively. The specific activity of hyaluronidase was much higher than that of any previously purified mucopolysaccharidases. The Vmax against hyaluronic acid reached 400 mmol of product per min per mg of protein at 22 degrees C. The peptostreptococcal hyaluronidase was also unique in that its optimum pH of activity was around neutrality, whereas other bacterial hyaluronidases were most active at acidic pHs.
High surface hydrophobicity of autoaggregating Staphylococcus aureus strains isolated from human infections studied with the salt aggregation test
Authors: Ljungh A , Hjertén S , Wadström T
Published: January 2020

A total of 209 strains of Staphylococcus aureus isolated from infections and 23 strains from nose cultures of healthy laboratory personnel were compared for relative surface hydrophobicity in the salt aggregation test (Lindahl et al., Biochim. Biophys. Acta 677:471-476, 1981). In the standard method, bacterial cell suspensions from blood agar-grown cultures were tested for visible aggregation by "salting out" in serial dilutions of ammonium sulfate (0.1 to 1.6 M [final concentration]). Bacteria were defined as extremely hydrophobic when showing autoaggregation in saline or in 0.002 M sodium phosphate buffer (pH 6.8). Using this definition, we found a large number of strains isolated from various infections to be very hydrophobic: 123 of 135 strains from patients with septicemia (91%), 54 of 60 strains from wound infections (90%), and 12 of 14 strains from urinary tract infections (86%). In contrast, only 9 of 23 strains from nose cultures of healthy carriers (39%) were autoaggregating. A total of 12 autoaggregating strains were grown on various solid and liquid media. Only growth on hematin agar was found to completely suppress surface hydrophobicity as revealed by our salt aggregation test method, and growth in liquid media prevented the expression of hydrophobicity in most strains. Growth at 20 or 42 degrees C or under anaerobic conditions did not affect hydrophobicity. Cells harvested from various phases of growth did not differ significantly in surface hydrophobicity. Heating washed cell suspensions at 56 degrees C did not affect the salt aggregation test values, whereas heating the cell suspensions at 80 and 100 degrees C caused a significant decline in hydrophobicity. The addition of ethylene glycol (25% [vol/vol] final concentration) prevented the autoaggregation of 10 of the 12 strains. Likewise, treating the cell suspensions with proteolytic enzymes decreased the surface hydrophobicity, indicating that surface proteins contribute to high surface hydrophobicity of autoaggregating strains.
Modulation of in vitro natural cell-mediated activity against enteropathogenic bacteria by simple sugars
Authors: Nencioni L , Villa L , Boraschi D , Tagliabue A
Published: January 2020

Lymphoid cells from mouse Peyer's patches and spleens were tested in a 2-h in vitro assay for their natural activity against the enteropathogenic bacteria Salmonella typhimurium, Salmonella enteritidis, Salmonella tel aviv, and Shigella sp. X16. The antibacterial activity expressed by normal cells was detected against all the bacterial strains tested with the exception of Peyer's patch lymphocytes against S. tel aviv and splenocytes against Shigella sp. X16. To determine whether the different expression of natural antibacterial activity might be due to lectin-like proteins interacting with the saccharidic moieties of the bacterial wall, 11 simple sugars were preincubated with the effector cells before the in vitro assays. We found that some of them could block the natural antibacterial activity as well as induce antibacterial activity when this was not spontaneously expressed. Interestingly, a different panel of sugars among those employed was observed to affect the antibacterial activities for each of the above-mentioned bacterial targets and each effector cell. However, the same panel of sugars was able to block or stimulate the lymphocyte activity when bacteria with the same somatic antigens as two substrains of S. typhimurium and one strain of Salmonella schottmuelleri were employed. To further investigate the interaction between effector cells and bacteria, effector cells or Shigella sp. X16 targets were treated with proteolytic, glycolytic, and lipolytic enzymes before the in vitro assays. Furthermore, EDTA was used to analyze the role of divalent cations in this experimental system. The results obtained suggest that lectin-like proteins playing a role in this interaction are present not only on lymphocytes but also on bacteria and that divalent cations are essential for the expression of in vitro antibacterial activity.
Role of nasopharyngeal colonization with and without bacteremia in the protection of infant rats against Haemophilus influenzae type b challenge
Authors: Gilsdorf J R , Ferrieri P
Published: January 2020

Nasopharyngeal colonization of infant rats with Haemophilus influenzae type b was investigated by two methods of intranasal inoculation. After traumatic instillation of the bacteria, 100% of the animals became colonized, compared with 75.5% of animals after atraumatic instillation. Among colonized rats, significantly more animals in the traumatic group developed bacteremia compared with those in the atraumatic group. Rats in the traumatic group had an onset of bacteremia at a mean of 2.6 days after inoculation compared with 7.3 days in the atraumatic group. The duration of colonization and bacteremia was the same in both groups. The majority of heavily colonized rats developed bacteremia compared with none of the lightly colonized rats. Thus, the development of bacteremia appeared to be related independently to both heavy colonization and traumatic instillation. Protection against intraperitoneal bacterial challenge with H. influenzae type b developed in rats that had been bacteremic; in the majority of animals, this correlated with the development of serum bactericidal activity. Protection and bactericidal activity were only rarely observed in nonbacteremic rats that had been either heavily or lightly colonized. The development of serum bactericidal activity was not related to either the duration or peak level of bacteremia. Thus, in this rat model, H. influenzae type b nasopharyngeal colonization without bacteremia did not appear to stimulate circulating antibodies that protected the animals against challenge.
Actinobacillus actinomycetemcomitans strains Y4 and N27 adhere to hydroxyapatite by distinctive mechanisms
Authors: Kagermeier A S , London J
Published: January 2020

Actinobacillus actinomycetemcomitans strains Y4 and N27 absorb to spheroidal hydroxyapatite in roughly the same numbers per milligram of substrate and with the same tenacity as two previously tested Cytophaga species. Although the two strains of A. actinomycetemcomitans exhibited similar affinities and number of binding sites for SHA, their response to enzyme treatment and heating were very different. The capacity of strain Y4 to attach to spheroidal hydroxyapatite was diminished by treatment with proteases and phospholipases and was unaffected by neuraminidase, while strain N27 was unaffected by proteases and phospholipases and lost its binding capabilities when treated with neuraminidase.
Identification and occurrence of Vibrio cholerae flagellar core proteins in isolated outer membrane
Authors: Richardson K , Parker C D
Published: January 2020

Sodium dodecyl sulfate-urea polyacrylamide gel electrophoresis of outer membranes from a flagellated and an isogenic nonflagellated strain of Vibrio cholerae (classical, Inaba) suggested that two proteins were absent from the nonflagellated strain. Immunoblot examination of such preparations demonstrated that two proteins, present only in outer membrane from the flagellated strain, were associated with flagella. Analysis of purified flagellar cores from strains CA401 and N16961 (El Tor, Inaba) by electron microscopy, sodium dodecyl sulfate-urea polyacrylamide gel electrophoresis, and immunoblotting showed that these two proteins, with apparent molecular weights of 47,000 and 49,000, composed the flagellar core. Antiserum specific for flagellar core proteins did not agglutinate or inhibit the motility of intact V. cholerae. These latter findings suggested that, for intact cells, the flagellar core proteins are not accessible to antibody.
Pathogenicity, stability, and immunogenicity of a knobless clone of Plasmodium falciparum in Colombian owl monkeys
Authors: Langreth S G , Peterson E
Published: January 2020

The pathogenicity, immunogenicity, and morphological stability of a knobless clone of strain FCR-3 of the human malaria parasite Plasmodium falciparum was investigated in Aotus monkeys. An early knob-bearing (K+), wild-type isolate of strain FCR-3 and the D3 knobless (K-) clone were adapted to Aotus monkey erythrocytes in continuous culture, establishing the parasites in Aotus cells without exposure to in vivo cellular or humoral immune responses. All monkeys, intact or splenectomized, which were infected with wild-type FCR-3 adapted to Aotus cells in vitro, developed virulent infections and had to be drug treated. The intact nonsplenectomized animals which received knobless D3 cloned parasites did not develop virulent infections even after multiple infections. The splenectomized monkeys which received the K- D3 clone had virulent infections. Late-stage wild-type K+ parasites sequestered in both intact and splenectomized monkeys, whereas late-stage D3 K- parasites did not sequester in the splenectomized animals. These results suggest that two elements affected the pathogenicity of the malaria parasites in these experiments. Knobs on K+-infected erythrocytes enabled these parasites to sequester, presumably by attachment to capillary endothelium. When present, the spleen eliminated circulating K- late-stage erythrocytes, presumably by selection on the basis of their nondeformability. Although clone D3 K- parasites are nonvirulent in intact monkeys, they induced some immunological protection against challenge with wild-type K+ parasites. The surface morphology of K--infected erythrocytes remains unaltered throughout these experiments, suggesting that loss of knobs is a stable condition.
Stimulation by staphylococcal enterotoxin A of nonspecific resistance of mice to microbial infection
Authors: Otani T , Katami K , Osada Y
Published: January 2020

The effects of staphylococcal enterotoxins A, B, and C2 (SEA, SEB, and SEC2) on the resistance of mice to microbial infections were studied. SEA stimulated the resistance strongly, whereas SEB and SEC2 had no such effect. Treatment with SEA increased the number of peripheral blood polymorphonuclear leukocytes significantly within 4 h, and these polymorphonuclear leukocytes exhibited a higher chemiluminescence response than those of the controls. Furthermore, a significant increase in spleen weight was also observed in mice treated with SEA, and histologically that increase was characterized by a proliferation of lymphoblast-like cells which were stained with antibody to mouse Thy-1 but not with antibody to mouse immunoglobulin G by indirect immunofluorescence. As expected from the above findings, the treatment of nude mice (nu/nu) with SEA failed to protect them against Escherichia coli infections, whereas treatment of heterozygous (nu/+) controls afforded such protection. This was in part supported by the fact that the chemiluminescence response of peripheral blood polymorphonuclear leukocytes was increased significantly by treatment with SEA in nu/+mice but not in nu/nu mice.
Increased translocation of bacteria from the gastrointestinal tracts of tumor-bearing mice
Authors: Penn R L , Maca R D , Berg R D
Published: January 2020

Aerobic gram-negative bacilli and other indigenous gastrointestinal (GI) bacteria are important opportunistic pathogens in immunosuppressed cancer patients. These same bacteria frequently translocate from the GI tracts of mice immunosuppressed by single injections of certain anticancer drugs or by T-lymphocyte impairments. Since similar cellular and humoral immune deficiencies may be present in the tumor-bearing host, we sought to determine if progressive growth of a tumor alone would be sufficient to enhance the translocation of indigenous bacteria from the murine GI tract. Pathogen-free DBA/2 mice were injected intraperitoneally with 10(6) viable sarcoma 180 (S-180) cells or 0.5 ml of sterile buffer. Mesenteric lymph nodes, livers, spleens, and kidneys were tested for the presence of translocated aerobic GI bacteria on various days after tumor injection. Immunity was assessed by measuring footpad delayed-type hypersensitivity and serum hemagglutinins to sheep erythrocytes. Overall, translocated aerobic GI bacteria infected 33 of 92 S-180-bearing mice (36%) and only 9 of 99 control mice (9%) (P less than 10(-6)). Cumulatively, 50 of 460 sites (10.9%) in S-180-bearing mice were infected with translocated GI bacteria as opposed to only 9 of 485 sites (1.9%) in control animals (P less than 10(-7)). GI bacteria often translocated to infect more than one site in tumor-bearing mice, but not in controls. Aerobic gram-negative bacilli translocated 11 times in tumor-bearing mice, but only once in controls, even though the mean cecal population levels of these bacteria were relatively low (range, 4.33 to 5.28 log10 bacteria per g). The population levels of cecal aerobic bacteria were similar in S-180 and control mice throughout the period of observation. S-180 mice had significantly suppressed (P less than 0.04) delayed-type hypersensitivity and serum hemagglutinin responses when sensitized 4 or 8 days after S-180 injection. S-180 growth was associated with a neutrophilic leukocytosis and a slight drop in platelet counts; no bleeding was detected. Thus, the translocation of gram-negative bacilli and other indigenous aerobic bacteria from the GI tract to the mesenteric lymph nodes and other organs was increased in immunosuppressed S-180-bearing mice, and this increase was not caused by bacterial overgrowth in the intestines or by neutropenia.
Decreased delayed-type hypersensitivity and increased protection to Listeria monocytogenes seen in mice infected with mucoid and nonmucoid Pseudomonas aeruginosa
Authors: Blackwood L L
Published: January 2020

Infection of mice with Pseudomonas aeruginosa, washed and unwashed, mucoid and nonmucoid, altered subsequent immunity to Listeria monocytogenes. Mice were protected against lethal doses of L. monocytogenes yet exhibited decreased delayed-type hypersensitivity footpad swelling to sublethal doses. The mucoid coating of mucoid P. aeruginosa, an important pathogen in chronic bronchopulmonary disorders, imparted no additional immunomodulating capabilities to P. aeruginosa.
Outer membrane proteins of nontypable Haemophilus influenzae and reactivity of paired sera from infected patients with their homologous isolates
Authors: Hansen M V , Musher D M , Baughn R E
Published: January 2020

Normal human serum and acute or convalescent serum from patients infected with nontypable Haemophilus influenzae were tested for reactivity with electroblotted outer membrane proteins obtained from the homologous nontypable H. influenzae isolates. Of 12 patients, 8 had immunoglobulin G antibodies to outer membrane proteins from their own infecting nontypable H. influenzae isolates that were not present in normal human serum. Three patients had immunoglobulin antibody in convalescent serum that had been absent in acute serum, but no consistent outer membrane protein was involved in the sets of patient sera with outer membrane proteins examined.
Siderophore activity of pyoverdin for Pseudomonas aeruginosa
Authors: Cox C D , Adams P
Published: January 2020

Pseudomonas aeruginosa produces an extracellular compound with yellowish green fluorescence, called pyoverdin, which functions as a siderophore. The production of pyoverdin, formerly called fluorescein, is concomitant with the production of another siderophore, pyochelin. Pyoverdin is produced by P. aeruginosa in several forms, some of which were separated on gel filtration columns and on reverse-phase, high-pressure liquid chromatography columns. An active form of iron-free pyoverdin was purified to homogeneity. The elution of pyoverdin from the columns was monitored for absorbance, fluorescence, and siderophore activities. These activities, iron binding, and the stimulation of bacterial iron transport indicated that pyoverdin can function as a siderophore for P. aeruginosa. The siderophore function of pyoverdin may be related to the pathogenicity of this bacterium because pyoverdin stimulated growth not only in iron-deficient culture medium, but also in defined medium containing transferrin and in human serum or plasma.
Phagocytosis of Campylobacter jejuni and its intracellular survival in mononuclear phagocytes
Authors: Kiehlbauch J A , Albach R A , Baum L L , Chang K P
Published: January 2020

In vitro phagocytosis and intracellular survival of Campylobacter jejuni strain 2964 in mononuclear phagocytes were studied. The following three types of mononuclear phagocytes were used: a J774G8 peritoneal macrophage line derived from BALB/c mice, resident BALB/c peritoneal macrophages, and human peripheral blood monocytes. When C. jejuni and mononuclear phagocytes were combined at a ratio of 75:1, light microscopy, fluorescent microscopy, and electron microscopy all indicated that C. jejuni cells were readily phagocytized. The majority of C. jejuni cells were spirals immediately following ingestion and were rapidly converted to the coccal form within 4 to 8 h. Conversion from the spiral form to the coccal form was complete in the presence of phagocytes within 96 h. In control preparations without phagocytes, conversion began after 24 h and was complete after 48 h. The extent of phagocytosis over time was determined by observing Giemsa-stained preparations and counting the number of intracellular bacterial colony-forming units after removal of extracellular C. jejuni. Human monocytes ingested C. jejuni more rapidly and vigorously than murine macrophages. Intracellular survival of C. jejuni was examined by measuring the number of C. jejuni colony-forming units associated with phagocytes after phagocytosis for 2 h and removal of extracellular bacteria. C. jejuni survived intracellularly for up to 6 to 7 days.
Structure and surface exposure of protein IIs of Neisseria gonorrhoeae JS3
Authors: Judd R C
Published: January 2020

Colonies of Neisseria gonorrhoeae JS3, each bearing a predominate protein II (PII) type, were derived from a progenitor transparent colony. Five distinct PIIs were identified and isolated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The PII bands were excised from gels of unlabeled whole cells and from gels containing lysates of surface-radioiodinated bacteria. These were subjected to alpha-chymotrypsin digestion and two-dimensional peptide mapping, which allowed for a comparison of both the primary structures of the PIIs and the identification of surface-exposed regions of the molecules. The results demonstrated that PIIs are unrelated to either Protein I or Protein III in structure but are closely related to one another, sharing about two-thirds of the peptides generated by alpha-chymotrypsin. The remaining third of the peptides varied with each PII, resulting in unique portions of the molecule being exposed on the bacterial surface. However, the variable peptides were not always among the exposed peptides, suggesting that the structural differences in the PIIs occur at a discrete site (or sites) of the PII molecule and not randomly throughout the protein. Such alterations can result in the exposure of distant, nonvariant portions of the molecule to the surface, perhaps by conformational changes. These bacteria can thus present a variety of new immunodeterminant sites to the host during the course of disease.
Immunization against experimental murine salmonellosis with liposome-associated O-antigen
Authors: Desiderio J V , Campbell S G
Published: January 2020

Partially delipidated Salmonella typhimurium (O-1,4,5,12) lipopolysaccharide was incorporated into small multilamellar liposomes composed of either naturally occurring or synthetic phospholipids. Vaccination of mice with the liposome-lipopolysaccharide complexes induced a cellular response specific for O-1,4,5,12 determinants, as determined by the development of a delayed-type hypersensitivity reaction. The liposome-lipopolysaccharide vaccines were significantly more effective, compared with other nonviable vaccines tested, in protecting mice against a lethal intravenous challenge infection with virulent S. typhimurium. Protection afforded by the liposome-lipopolysaccharide vaccines was comparable to that conferred by a live S. typhimurium vaccine. Results suggest that liposome-induced modulation of the host immune response in favor of cell-mediated immunity may be more efficacious in preventing diseases in which cell-mediated immunity is of prime importance.
Binding of the two components of C2 toxin to epithelial cells and brush borders of mouse intestine
Authors: Ohishi I , Miyake M
Published: January 2020

C2 toxin elaborated by Clostridium botulinum types C and D is composed of two nonlinked protein components and has enterotoxic activity, for which the cooperation of these two components is necessary. In the present study, the binding of components I and II, the two components of C2 toxin, to isolated epithelial cells and brush borders of mouse intestine was examined. Immunofluorescence studies showed that component II, either trypsinized (T-II) or untrypsinized (UT-II), bound to the cells and the brush borders of mouse intestine, whereas component I alone did not. The binding of I was observed only when the cells and the brush borders were reacted with T-II, but not when they were reacted with UT-II. These results are consistent with the fact that the biological activities of C2 toxin are elicited by the combination of I and T-II, but not of I and UT-II. The in vitro binding of I and II to isolated brush borders of mouse intestinal cells also showed similar binding characteristics. The binding of I and II to brush borders was rapid and not temperature dependent. Ultracentrifugal analysis revealed that both I and T-II bound to microvillous membranes of the intestinal cells. The data from the present study indicate that the enterotoxic activity of C2 toxin is initiated by the binding of T-II to the microvillous membrane of intestinal cells followed by that of I, for which the site of the cell membrane is induced by the binding of T-II, but not of UT-II.
Characterization of two different antibody specificities recognizing distinct antigenic determinants in free lipid A of Escherichia coli
Authors: Brade L , Brade H
Published: January 2020

Antisera were raised in rabbits with acid-treated Re mutant bacteria from Salmonella minnesota and Escherichia coli and tested in a passive hemolysis assay with di- and monophosphorylated free lipid A of E. coli (LipA-Ac and LipA-HCl, respectively) coated onto sheep erythrocytes. Depending on the acid used to prepare the immunogen (acetic versus hydrochloric acid), different antibody specificities were obtained. Antiserum prepared against HCl-treated bacteria was found to react with both antigens to the same extent (i) in the passive hemolysis test, (ii) in the passive hemolysis inhibition test, and (iii) in absorption experiments, suggesting that antibodies in this antiserum recognize an antigenic determinant equally present in LipA-Ac and LipA-HCl. Antiserum raised against acetic acid-treated bacteria reacted with the homologous antigen (LipA-Ac) in the passive hemolysis and passive hemolysis inhibition test as well as in absorption experiments. However, the antiserum failed to react with the heterologous antigen (LipA-HCl) in the hemolysis test and during absorption, whereas in inhibition studies interaction of this antiserum with both antigens was observed. The inhibiting capacity of LipA-Ac was lower compared with that of LipA-HCl, indicating that the antigenic determinant of LipA-Ac is partly expressed by LipA-HCl in solution, but not when fixed on the surface of sheep erythrocytes. The role of glycosidically linked phosphate in lipid A is discussed with respect to antigenicity.
Purification and characterization of a phagocytosis-stimulating factor from phagocytosing polymorphonuclear neutrophils: comparison with granule basic proteins
Authors: Ishibashi Y , Yamashita T
Published: January 2020

Phagocytosis-stimulating factor (PSF) was purified by copper chelate chromatography and characterized in comparison with basic proteins in the granule of polymorphonuclear neutrophils. By copper chelate chromatography, PSF was eluted at pH 3.7; whereas cationic protein, lysozyme, and lactoferrin were eluted at pH 5.6, 5.1, and 4.0, respectively. Purified PSF has an approximate molecular weight of 16,000 and an isoelectric point at 8.7, which differ from those of basic proteins, such as cationic protein, lysozyme, and lactoferrin. Anionic substances such as DNA and heparin did not influence the phagocytosis-stimulating activity of PSF, whereas that of the granule basic protein fraction from resting polymorphonuclear neutrophils was abolished. PSF had little bactericidal activity against Escherichia coli and Staphylococcus aureus, whereas the granule basic protein fraction from resting PMNs had strong bactericidal activity against E. coli and weak activity against S. aureus. These results indicate that PSF is a basic protein which is distinguishable from cationic protein, lysozyme, and lactoferrin.
Elicitation of enteroluminal neutrophils by enterotoxigenic and nonenterotoxigenic strains of Escherichia coli in swine
Authors: Rose R , Moon H W
Published: January 2020

In intact neonatal piglets, two strains of enterotoxigenic Escherichia coli (ETEC), which could adhere to epithelial cells and thus colonize the small intestine, attracted greater numbers of neutrophils into the lumen and wall of the intestine than did a nonenteropathogenic strain of E. coli. Ligated loops of small intestine in 8-week-old pigs were used in attempts to identify the attributes of ETEC involved in stimulating an increased enteroluminal migration of neutrophils. A nonenteropathogenic strain of E. coli did not attract neutrophils into the intestinal lumen in this model. However, three of the five ETEC strains tested did so. The three positive strains all produced heat-stable enterotoxin type b (STb). Neither of the negative ETEC strains produced STb. An STb-containing culture supernatant prepared from a strain of E. coli which contained an STb plasmid did not attract significantly more neutrophils than did a control supernatant prepared from the same strain of E. coli without the plasmid. The ETEC strains which attracted neutrophils in loops did not associate intimately with loop villi more consistently, nor did they grow to higher numbers in loops than strains which did not. It was concluded that there are increased numbers of neutrophils in the intestinal lumen during ETEC infection of newborn pigs. However, attempts to identify the attribute(s) of ETEC responsible for eliciting enteroluminal neutrophils were not successful.