bluuebunny/crossref_metadata_2025 huggingface dataset:
Significance of Abnormal Rabbit Ileal Histology in the Pathogenesis of Diarrhea
Authors: Donowitz Mark , Charney Alan N. , Hynes Richard , Formal Samuel B. , Collins Hugh
Published: January 2020

In spite of several macroscopic criteria for predicting the presence of histological abnormalities in rabbit ileum, microscopic ileal abnormalities still can escape detection. The effect of histologically abnormal rabbit ileum was evaluated on basal intestinal absorption, on basal absorption, on basal adenylate cyclase activity, and on cholera toxin-induced secretion and cholera toxin-induced stimulation of adenylate cyclase activity. Compared to histologically normal rabbit ileum, the presence of histological abnormalities was associated with decreased basal intestinal water, Na, Cl, and glucose absorption, absent glucose-dependent water absorption, and elevated basal adenylate cyclase activities. However, histologically abnormal rabbit ileum responded to inoculation of purified cholera toxin with stimulation of intestinal water secretion and adenylate cyclase activity similar to that in histologically normal ileum. These data have implications concerning the design of experiments that attempt to study the pathogenesis of diarrheal diseases by correlating changes in ileal transport with changes in ileal mucosal adenylate cyclase activity. In spite of abnormal ileal histology, studies of intestinal secretory states which attempt to define the role of adenylate cyclase in secretory processes can be performed provided animals are used as their own controls. However, when groups of animals are compared, the presence of an histologically abnormal ileum can cause changes in basal and intestinal secretagogue-stimulated ileal water and electrolyte transport and in basal and intestinal secretagogue-stimulated mucosal adenylate cyclase activity which can lead to erroneous conclusions if the presence of the abnormal ileal histology is not considered.
Synergistic protection against experimental cholera by immunization with cholera toxoid and vaccine
Authors: Peterson J W
Published: January 2020

Rabbits were immunized with two parenteral injections of Wellcome toxoid PX389A, Wyeth toxoid 20101, or Merck bivalent vaccine. Other groups of rabbits were immunized with combinations of the Merck vaccine and each of the two toxoids. Antitoxin responses were monitored in each group of rabbits before livecell challenge of each animal by the ligated intestinal loop assay. Inaba and Ogawa strains of Vibrio cholerae were used for challenge experiments. Basically, the data indicate that the toxoids were equivalent in antigenic potency and antitoxin responses were unaffected by combination of the toxoids with the whole-cell vaccine. The 50 microgram doses of each toxoid as well as the 4 X 10(9) cells of the bivalent vaccine provided the same magnitude of protection against live-cell challenge with either Inaba or Ogawa vibrios. Immunization with either toxoid in combination with the bivalent vaccine resulted in a synergistic protective response against live-cell challenge of intestinal loops with V. cholerae. Synergistic protection was observed when toxoid and vaccine were administered together by the oral and parenteral routes. Maximum protection was obtained when rabbits were immunized with the combined toxoid-whole-cell vaccine administered by both oral and parenteral routes.
Pathogenesis of Marek's disease; effect of immunization with inactivated viral and tumor-associated antigens
Authors: Murthy K K , Calnek B W
Published: January 2020

Inactivated Marek's disease virus-infected chicken kidney cells and inactivated MSB-1 lymphoblastoid Marek's disease tumor cells were used to immunize chickens as virus- and tumor-associated antigens, respectively. Immune and nonimmune birds were then challenged by exposure to live virulent Marek's disease virus. Both vaccines protected significant numbers of chickens (P less than 0.05) against subsequent tumor development, although viral antigen appeared superior to tumor antigen. After challenge, the early appearance of viral antigen, infected lymphocytes, and degenerative changes in lymphoid organs was inhibited only by the viral antigen vaccine, whereas the early appearance of cells bearing tumor antigen was prevented by both vaccines. These results support the hypothesis that effective immunity in Marek's disease could be directed against either virus replication and spread or events associated with transformation and proliferation of lymphoid cells.
Generalized infection and lack of delayed hypersensitivity in BALB/c mice infected with Leishmania tropica major
Authors: Nasseri M , Modabber F Z
Published: January 2020

The susceptibility of a few strains of mice to a subcutaneous injection of Leishmania tropica major, the causative agent of cutaneous leishmaniasis in humans, was studied. The infection in six strains (CBA, AKR/J, AKR/cu, C57BL/6, A/J, and C3H) remained cutaneous, and the animals recovered within 3 to 4 months. In contast, the infection in BALB/c became generalized and killed 1005 of infected animals. Intraperitoneal injection of infected liver of BALB/c to A/J and syngeneic mice produced a lethal disease in BALB/c but no infection in A/J mice. Lower doses of the parasite produced a lethal infection in BALB/c but no apparent disease in A/J. Hence, the host rather than the parasite is responsible for the outcome of the disease. The peak antibody titer of BALB/c mice was not significantly higher than that of A/J mice. However, BALB/c failed to show any delayed hypersensitivity to leishmania tested by footpad reaction, whereas A/J mice showed a strong response.
Hemolytic complement and serum C3 levels in Zebu cattle infected with Trypanosoma congolense and Trypanosoma vivax and the effect of trypanocidal treatment
Authors: Rurangirwa F R , Tabel H , Losos G , Tizard I R
Published: January 2020

Total hemolytic complement and C3 levels were found to drop to 6.25% and 50% of preinfection levels, respectively, during trypanosome infections. Chemotherapeutic elimination of the trypanosomes with Berenil led to recovery of preinfection levels within 7 days and 11 days when cattle infected with Trypanosome congolense and Trypanosoma vivax, respectively, were treated 37 days after onset of infection. Recovery was slower in T. vivax-infected cattle treated on day 50. Berenil treatment had no effect on complement levels in control animals. The possible causes and implications of these low complement levels in bovine trypanosomiasis are discussed.
Virulence of
Streptococcus mutans
: Restoration of Pathogenesis of a Glucosyltransferase-Defective Mutant (C4)
Authors: Hirasawa Masatomo , Kiyono Hiroshi , Shiota Tetsuo , Hull Richard A. , Curtiss Roy , Michalek Suzanne M. , McGhee Jerry R.
Published: January 2020

Previous studies have shown that a mutant (designated C4) of
Streptococcus mutans
6715 wild type (WT) is defective in glucosyltransferase (GTF)-synthesized insoluble glucan and is avirulent in gnotobiotic rats. This study investigated the factors which would render this mutant virulent in gnotobiotic rats. Microbial analysis of plaque from gnotobiotic rats (45 days old) infected with a mixture of C4 and virulent
S. mutans
PS-14 (approximately 15,000 C4 organisms to each
S. mutans
PS-14) yielded higher numbers of C4 organisms than
S. mutans
PS-14. These animals exhibited significantly lower caries scores than did gnotobiotic rats (age, 45 days) monoassociated with
S. mutans
PS-14. Similar mixed infection studies using C4 and an avirulent, aggregation-defective mutant of
S. mutans
6715 WT (designated UAB 165) which exhibits GTF activity similar to that of the parent strain resulted in plaque consisting almost exclusively of UAB 165 and low caries activity. However, high levels of both C4 and UAB 165 in plaque and high caries activity were observed in gnotobiotic rats infected at weaning with C4 followed by UAB 165 3 days later. When dried
S. mutans
6715 WT culture supernatant containing GTF activity was mixed with diet provided rats monoassociated with C4, significant caries activity was observed. Insoluble glucan supplemented in diet did not restore C4 to virulence; however, admixture of suboptimal GTF-rich supernatant with insoluble glucan and C4 resulted in high caries activity in gnotobiotic rats. These results suggest that in vivo restoration of pathogenesis of a GTF-defective mutant of
S. mutans
can be achieved either by complementation with a mutant defective in aggregation properties or by providing exogenous GTF and glucan from the parent
S. mutans
6715 WT.
Carbon dioxide metabolism by Actinomyces viscosus: pathways for succinate and aspartate production
Authors: Brown A T , Breeding L C
Published: January 2020

14C-labeled bicarbonate was incorporated into trichloroacetic acid-insoluble material by cell suspensions of A. viscosus strain M100 and also into the four-carbon fermentation product, succinate, but not into the three-carbon fermentation product, lactate. The initial step in the conversion of 14C-labeled bicarbonate into both trichloroacetic acid-insoluble material and succinate was catalyzed by the enzyme phosphoenolypyruvate carboxylase, which served to convert the glycolytic intermediate, phosphoenolpyruvate, and bicarbonate to the four-carbon compound, oxalacetate. The metabolic fate of oxalacetate was its conversion to either trichloroacetic acid-insoluble material or succinate. One pathway by which oxalacetate may be metabolized into acid-insoluble material is via its conversion to the biosynthetic precursor aspartate by the action of glutamate aspartate aminotransferase. One source of the alpha-amino group of aspartate was the ammonium ion, which could be incorporated into glutamate, the substrate of the glutamate aspartate aminotransferase reaction, by the action of a reduced nicotinamide adenine dinucleotide phosphate-dependent glutamate dehydrogenase whose reducing equivalents could be derived from the nicotinamide adenine dinucleotide phosphate-dependent oxidative reactions of the hexose monophosphate pathway catalyzed by glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase. Alternatively, oxalacetate was converted to the fermentation product, succinate, through the sequential action of malate dehydrogenase, fumarase, and succinic dehydrogenase. The resolution and partial purification of phosphoenolpyruvate carboxylase, glutamate aspartate aminotransferase, glutamate dehydrogenase, malate dehydrogenase, fumarase, and succinic dehydrogenase are also reported.
Aerosol infection of mice with Bordetella pertussis
Authors: Sato Y , Izumiya K , Sato H , Cowell J L , Manclark C R
Published: January 2020

Aerosol inhalation of Bordetella pertussis Tohama phase I resulted in a reproducible and uniform infection of mice (strain DDY or ICR). Mice in groups of 10 exposed for 30 min to aerosols generated from bacterial suspensions of 10(9) and 10(10) organisms per ml resulted in mean bacterial counts of 2.3 (+/- 0.3) X 10(4) and 1.0 (+/- 0.3) X 10(5) colony-forming units, respectively, in the lung of each animal. Subsequent studies using a 30-min aerosol inoculation of ICR mice with 2 X 10(9) bacterial cells per ml showed: (i) B. pertussis cells reached a maximum of about 10(7) colony-forming units per lung 14 days after inhalation. (ii) Deaths (10 to 100%, depending on mouse age) occurred 10 to 14 days after exposure. (iii) The lung weight and the leukocyte count increased from basal values of 100 mg and 10(4) leukocytes per mm3 to a plateau of 950 mg and 1.95 X 10(5) leukocytes per mm3, respectively, 14 days after challenge. (iv) There was a significantly reduced rate of body weight gain by infected mice compared to noninfected mice. (v) With mortality as the criterion for disease, susceptibility varied with the age of mice as follows: 10 days old greater than 18 greater than 28 greater than 49. (vi) Bacteria were associated with ciliated respiratory epithelial cells by scanning electron microscopy.
Purification and characterization of Clostridium perfringens delta-toxin
Authors: Alouf J E , Jolivet-Reynaud C
Published: January 2020

Delta-toxin, an extracellular hemolysin released by Clostridium perfringens type C, was purified from culture supernatant fluid by sequential ammonium sulfate precipitation, thiol-Sepharose gel chromatography, isoelectric focusing, and Sephadex G-75 gel filtration. The purified preparation had a specific activity of 320,000 hemolytic units per mg of protein and was homogeneous, as determined by immunochemical and electrophoretic tests. This toxin was characterized as a single polypeptide chain composed of 391 amino acid residues, 30% of which were hydrophobic. The molecular weight was found to be 42,000, and the isoelectric point was pH 9.1. Delta-toxin appeared to be amphiphilic by charge shift electrophoresis in a three-detergent system. It was immunogenic in rabbits and lethal to mice at a dose of 0.12 micrograms. The lytic activity of delta-toxin was restricted to erythrocytes of even-toed ungulates (sheep, goats, and pigs). This activity was inhibited by GM2 ganglioside but not by other gangliosides, cholesterol, lecithin, or sphingomyelin.
Immune Response in the Bovine Mammary Gland After Intestinal, Local, and Systemic Immunization
Authors: Chang C. C. , Winter A. J. , Norcross N. L.
Published: January 2020

The immune response in mammary glands of cattle was measured after intestinal, local, and systemic immunization with T4 bacteriophage. Nonlactating pregnant cows were immunized by infusions into the intestine or mammary gland and by subcutaneous injections in the region of the prescapular or external inguinal lymph nodes. Titers of antibodies of different isotypes were measured in serum and in lacteal secretions by enzyme-linked immunosorbent assay, and numbers of cells producing antibodies of each isotype were determined in lacteal secretions by the Jerne plaque assay. Substantial increases in immunoglobulin G subclass 1 (IgG1) and IgG2 antibody titers were detected in serum and lacteal secretions of animals immunized through an intestinal fistula. IgM and IgA antibody responses were low or undetectable. Low numbers of IgA and IgG1 plaque-forming cells were occasionally detected. It is proposed on the basis of these data that migration of antigen-stimulated IgG lymphoblasts, and perhaps of antigen, to spleen and peripheral lymph nodes may be dominant events after intestinal immunization of ruminants. This is consistent with the predominance of serum-derived IgG antibodies in colostrum and milk. Intramammary infusion of antigen gave rise to increases in antibody titers in all classes which were greater not only in lacteal secretions but also in blood serum than with either systemic route used. There was clear evidence from relative antibody titers for local synthesis of antibodies, principally IgA and IgG1, in the immunized glands. Comparison of IgA titers in secretions from the immunized glands with those in serum also suggested that locally synthesized IgA antibodies may have contributed in some measure to serum titers. Local synthesis in both immunized and nonimmunized glands was also reflected by the presence of increased numbers of IgA and IgG1 plaque-forming cells. It is hypothesized that antibody-forming cells responsible for local synthesis originated in lymphoid tissue within the mammary gland or from peripheral lymph nodes, depending upon the route of immunization.
Microbicidal cationic proteins of rabbit alveolar macrophages: amino acid composition and functional attributes
Authors: Patterson-Delafield J , Szklarek D , Martinez R J , Lehrer R I
Published: January 2020

We purified two microbicidal cationic proteins, MCP-1 and MCP-2, from rabbit alveolar macrophages. MCP-1 was remarkably rich in arginine (25.5 mol%) and half cystine (18.7 mol%) residues and constituted approximately 1.5% of the total protein content of Freund adjuvant-elicited alveolar macrophages. MCP-2 was approximately half as abundant as MCP-1 and contained relatively less arginine (14.9 mol%) and half cystine (9.8 mol%). The amino acid compositions of MCP-1 and MCP-2 resembled those reported for the lysosomal cationic proteins of rabbit granulocytes, but were distinct from those of any known histone. MCP-1 (1 microgram/ml) killed 99.6% of Candida albicans in 20 min, whereas MCP-2 killed approximately 80% under similar conditions. Both proteins rapidly suppressed O2 consumption by C. albicans and induced a rapid loss of intracellular 86Rb+. Although more information is needed about the biological origin, distribution, and roles of macrophage microbicidal proteins, it seems likely that MCP-1 and MCP-2 contribute to the microbicidal efficacy of rabbit alveolar macrophages.
Interaction of influenza virus with mouse macrophages
Authors: Rodgers B , Mims C A
Published: January 2020

Mouse peritoneal and alveolar macrophages differed substantially in their response to influenza in vitro. Immunofluorescent and infectious-center techniques showed that viral proteins were produced in only a small subpopulation (17%) of peritoneal macrophages and that these infected cells were removed from culture by 3 days postinfection. In contrast, alveolar macrophages were highly susceptible to influenza, and viral antigens were produced in all cells. This was accompanied by a cytopathic effect and cell death. However, no infectious virus was released and the infection was considered abortive. With mouse cytomegalovirus, however, both alveolar and peritoneal macrophages were equally restrictive, and viral antigens were produced in only 1 to 5% of either cell population. No significant differences were observed between mouse-virulent and -avirulent strains of influenza in their interaction with macrophages either in vitro or in vivo. In vivo, both strains induced an influx of cells to the alveolar spaces by 3 to 4 days postinfection, and this was reflected by a 5- to 10-fold increase in the number of "macrophages" in harvest fluids at this time. Many of these cells had an altered morphology compared with alveolar macrophages from uninfected mice, and the cell population as a whole was not susceptible to influenza. However, this resistance was lost by 7 days of in vitro culture.
Entrapment of human leukocyte interferon in the aqueous interstices of liposomes
Authors: Anderson P , Vilcek J , Weissmann G
Published: January 2020

Human leukocyte interferon has been trapped in the aqueous interstices of multilamellar liposomes (phosphatidylcholine, dicetyl phosphate, and cholesterol [7:2:1]). Such liposomes trapped [3H]inulin (aqueous space marker) and interferon to the extent of 0.22 +/- 0.01 mg (n = 8) and 350 +/- 54 U (n = 4) per mumol of liquid, respectively, as judged by molecular sieve chromatography. Interferon trapped within liposomes was resistant to tryptic digestion under conditions which completely inactivated free interferon. Studies in which interferon was added to preformed liposomes excluded the possibility that interferon bound nonspecifically to the outer layer of the multilamellar liposomes. When interferon was added to the aqueous medium in which liposomes of various net surface charges were permitted to form, trapping of interferon varied directly with the interlamellar aqueous compartments of the liposomes. The demonstration that stable liposomes can entrap interferon suggests that these may constitute suitable vectors for the delivery of interferon to cells.
Antibody-independent binding of the first component of complement (C1) and its subcomponent C1q to the S and R forms of Salmonella minnesota
Authors: Clas F , Loos M
Published: January 2020

Strong bactericidal effects of normal guinea pig and human sera against the Salmonella minnesota S form and an R form (Re) depend on Ca2+, complement component C4, and subcomponent C1q of complement component C1. Therefore, the interaction of C1 and C1q with these forms was investigated. The bacteria directly bound subcomponent C1q, as demonstrated by fixation and transfer tests and by fluorescent methods. Binding of macromolecular C1 was shown by fixation and transfer tests and by C4 consumption. C1 fixation and transfer tests provide evidence that C1 and C1q were bound more tightly to the Re form than to the S form. At physiological ionic strength, all cell-bound molecules were released from the S form, whereas at least 60% remained on the cell surface of the Re form. The Re form showed another binding behavior for C1: preincubation of bacteria with purified C1q totally prevented C1 uptake by the S form, compared to only 10% inhibition of the uptake by the Re form. Therefore, we conclude that macromolecular C1 is bound differently by the S form than by the Re form. The analysis of five other core-deficient mutants of S. minnesota (Ra, Rb, Rc, Rd1, and Rd2) revealed that the difference could be explained by a deficiency of the O-specific polysaccharide. In contrast, all the C1q bound to Ra, Rb, and Rc mutants was detectable by the transfer test. Therefore, we postulate that binding of macromolecular C1 to these mutants must be due to an additional C1 subcomponent besides C1q.
In Vitro Identification and Characterization of a Virus Isolated from a Dog with Neurological Dysfunction
Authors: Baumgärtner Wolfgang K. , Metzler Alfred E. , Krakowka Steven , Koestner Adalbert
Published: January 2020

A virus, 78-238, isolated from the cerebrospinal fluid of a dog with neurological dysfunction, was characterized as a paramyxovirus. This conclusion was supported by viral cytopathic effects and morphological appearance of virions and nucleocapsids in infected cells. Nucleocapsids were found in the cytoplasm of all infected cells and in the nuclei of 0.001% of these cells. Growth curves revealed that a high percentage (≥76%) of infectious progeny virus was cell released. Persistent infection of Vero cells with 78-238 showed a consistently high percentage of fluorescence-positive cells and a low proportion of hemadsorption-positive cells. Serological studies indicate that the virus was closely related to Simian virus 5 and reference canine parainfluenza virus.
Role of antibody to leukocytosis-promoting factor hemagglutinin and to filamentous hemagglutinin in immunity to pertussis
Authors: Sato Y , Izumiya K , Sato H , Cowell J L , Manclark C R
Published: January 2020

Gamma globulins were obtained from rabbits hyperimmunized with the filamentous hemagglutinin (FHA) or the leukocytosis-promoting factor hemagglutinin (LPF.HA) of Bordetella pertussis. Double immunodiffusion analyses showed the antibodies to be highly specific for the homologous antigen. Intraperitoneal injection of anti-FHA or anti-LPF.HA into 10-day-old ICR mice 30 min before aerosol challenge with B. pertussis protected the mice from disease as evidenced by survival and a normal rate of gain in body weight. Both anti-LPF.HA and anti-FHA enhanced the clearance of B. pertussis from the lung and prevented leukocytosis which normally occurs after aerosol infection of mice with B. pertussis. Anti-LPF.HA, but not anti-FHA, neutralized the leukocytosis-promoting and histamine-sensitizing activities of LPF.HA when incubated with the purified protein in vitro. Anti-FHA, but not anti-LPF.HA, prevented the attachment of B. pertussis to mammalian cells (HeLa and Vero) in culture.
Antigenic modification: its relation to protective host resistance in murine salmonellosis
Authors: Bigley N J , Smith R A , Warren P , Minahan W T , Kreps D P
Published: January 2020

Both the physical state of the immunogen and the route of immunization were found to be extremely important in inducing effective host resistance against salmonellosis.
Protein synthesis in HeLa or Henle 407 cells infected with Shigella dysenteriae 1, Shigella flexneri 2a, or Salmonella typhimurium W118
Authors: Hale T L , Formal S B
Published: January 2020

The incorporation of [14C]leucine into protein was studied in two mammalian cell lines which had been infected with strains of Shigella dysenteriae 1, Shigella flexneri 2a, or Salmonella typhimurium W118. These cell lines differed in susceptibility to the effects of exogenously applied Shiga cytotoxin. All invasive shigella strains (which synthesize this toxin to a greater or lesser degree) were found to inhibit protein synthesis in both cell lines with equal efficiency. Leucine accumulation continued in these cells, but the labeled amino acid was preferentially incorporated into bacterial protein. S. typhimurium W118, which has not been shown to elaborate a Shiga-like toxin, had little effect on protein synthesis in infected host cells.
Pathogenesis of Listeria monocytogenes for gnotobiotic rats
Authors: Czuprynski C J , Balish E
Published: January 2020

Listeria monocytogenes colonized the gastrointestinal tract of adult germfree rats (10(10) to 10(11)/g, dry weight) within 24 h after oral exposure. Between 3 and 14 days after monoassociation, L. monocytogenes caused a self-limiting pseudomembranous colitis, bacteremia, and infection of the spleen and liver. Monoassociation of rats with Listeria for 8 weeks stimulated 32- and 4-fold increases in serum immunoglobulin A (IgA) and IgG, respectively, whereas serum IgM decreased 2-fold. The normal microbial flora was inhibitory to Listeria colonization, since L. monocytogenes was cleared from the gastrointestinal tract of formerly monoassociated rats within 20 days after conventionalization and did not colonize the gastrointestinal tract of conventional rats after intragastric instillation of 10(8) viable L. monocytogenes. Listeria-monoassociated rats delivered large litters of healthy pups whose gastrointestinal tracts were slowly colonized with L. monocytogenes. between 3 and 60 days of age, Listeria-monoassociated rat pups exhibited eight- and fourfold increases in serum IgG and IgM, respectively; however, serum IgA was elevated (16-fold) only at 9 to 15 days of age. Adult Listeria-monoassociated rats had acquired cellular resistance to intravenous challenge with L. monocytogenes. Prolonged monoassociation of L. monocytogenes in rats attenuated its virulence for conventional rats.
Comparative sensitivity of Histoplasma capsulatum conidiospores and blastospores to oxidative antifungal systems
Authors: Howard D H
Published: January 2020

The comparative sensitivity of blastospores and conidiospores of Histoplasma capsulatum to hydrogen peroxide, to hydrogen peroxide and halides, and to a combination of hydrogen peroxide and halide with the enzyme myeloperoxidase was studied. Blastospores of different strains of H. capsulatum varied in their sensitivity to hydrogen peroxide. This variation correlated with the amount of catalase in cell-free extracts from the strains. Blastospores and conidiospores of a single isolate were about equally susceptible to hydrogen peroxide, but this sensitivity could obviously vary with the catalase content of the two types of spores. Halides augmented the antifungal activity of hydrogen peroxide for both types of spores. Iodide was far more efficient in this regard than was chloride. A crude granule lysate from guinea pig polymorphonuclear leukocytes was quite inhibitory to blastospore but not to conidiospore germination. A study of the myeloperoxidase activity of such preparations against blastospores was thus precluded. A sample of a very highly purified human myeloperoxidase functioned in the presence of hydrogen peroxide and either iodide or chloride to prevent germination of both blastospores and conidiospores. The preparation had no toxicity for spores apart from its interaction with hydrogen peroxide and halides.
Competition between congenic Escherichia coli K-12 strains in vivo
Authors: Onderdonk A , Marshall B , Cisneros R , Levy S B
Published: January 2020

The ability of Escherichia coli to colonize the large bowels of animals is related to many factors inherent to the intestinal environment and the bacterium. The use of germfree mice eliminates the competition between E. coli and the other microflora and allows most E. coli strains to colonize. We found that E. coli K-12 strains differing in chromosomal antibiotic resistance could monoassociate in germfree mice in large numbers. However, when two or more strains were in competition with each other, we detected quantitative differences in the abilities of the strains to colonize. The order of colonizing ability was as follows: nalidixic acid resistance greater than streptomycin resistance greater than rifampin resistance. We also found that a nalidixic acid-resistant strain bearing plasmid pBR322 colonized less efficiently and at lower levels when in competition with the nalidixic acid-resistant strain. Studies of the membrane proteins of the various strains indicated that changes in membrane proteins occurred concomitantly with altered resistance to antimicrobial agents. These results suggest that chromosomally linked alterations in antimicrobial sensitivity may also reflect changes in membrane proteins and a decreased ability to colonize mammalian intestines in otherwise isogenic bacterial strains.
Role of surface mannan in the adherence of Candida albicans to fibrin-platelet clots formed in vitro
Authors: Maisch P A , Calderone R A
Published: January 2020

An alkali-soluble extract from a cell wall preparation of Candida albicans was conjugated to sheep erythrocytes (SRBC) by using periodate oxidation or concanavalin A. Conjugated SRBC readily attached to a fibrin-platelet matrix, whereas nonconjugated SRBC did not. To determine the active component which promoted attachment of SRBC, the alkali-soluble fraction was treated with alpha-mannosidase, pronase, or glusulase or chemically degraded by acetolysis. The treated extract was then reconjugated with SRBC, and attachment was measured. When treated with alpha-mannosidase or degraded by acetolysis, the alkali-soluble extract failed to promote the adherence of SRBC to the fibrin-platelet matrix. Pronase- or glusulase-digested extract promoted attachment equally as well as untreated controls. In addition, when preabsorbed with antiserum to whole cells of C. albicans, the alkali extract abrogated the inhibition of adherence by antiserum, thus indicating its antigenicity. The extract consisted primarily of polysaccharide (72%) and contained a small amount of protein (less than 1%). Mannose and glucose (ratio, 3:1) were detected by gas-liquid chromatography. These data indicate that cell surface mannan may play an important role in the adherence of C. albicans to the fibrin-platelet matrices which form in vivo on the endocardium of heart valves.
Monoclonal antibodies to stage-specific, species-specific, and cross-reactive antigens of the rodent malarial parasite, Plasmodium yoelii
Authors: Taylor D W , Kim K J , Munoz P A , Evans C B , Asofsky R
Published: January 2020

Eighteen hybridoma cell lines were used to study species-specific, stage-specific, and serological cross-reactive antigens of the rodent malarial parasite, Plasmodium yoelii. Specificity and location of plasmodial antigens were determined by indirect fluorescent-antibody analysis. Results showed that a minimum of 12 distinct plasmodial antigens could be distinguished by the 18 hybridomas. Antigens were found on the surface or within the cytoplasm of the parasite, but not on the surface of erythrocytes from infected animals. The majority (11 of 12) of antigens were present in all erythrocytic stages of the parasite, but one was stage-specific for merozoites. Additional studies showed that 6 of 18 of the monoclonal antibodies identified species-specific antigens, 2 of 18 recognized antigens confined to related rodent malarial parasites (Plasmodium berghei, Plasmodium vinckei, and Plasmodium chabaudi), whereas 8 of 18 detected cross-reactive antigens common to rodent, primate (Plasmodium knowlesi, Plasmodium falciparum), and avian (Plasmodium gallinaceum) malarias.
Protection in rats immunized with Escherichia coli heat-stable enterotoxin
Authors: Klipstein F A , Engert R F , Clements J D
Published: January 2020

Rats immunized with a semipurified preparation of the Escherichia coli heat-stable (ST) enterotoxin conjugated with a protein carrier were protected against challenge with semipurified or purified ST and viable organisms of multiple heterologous serotypes that produce only ST (LT-/ST+), but they were not protected against heal-labile (LT) toxin or viable strains which produce LT either alone (LT+/ST-) or together with ST (LT+/ST+).
Induction of C3b-mediated phagocytosis in macrophages by distinct populations of lipopolysaccharide-stimulated lymphocytes
Authors: Wrigley D M , Saluk P H
Published: January 2020

Unelicited resident peritoneal macrophages do not significantly ingest erythrocytes coated with C3b. However, these resident macrophages can be induced to ingest via the C3b receptor when cocultured with peritoneal or splenic nonadherent cells obtained from mice previously injected with lipopolysaccharide. In this study, the extent of ingestion induced in resident macrophages was dependent on the number of stimulated nonadherent cells cocultured with the macrophages as well as on the amount of lipopolysaccharide injected in the mice from which the nonadherent cells were obtained. The ability of the stimulated nonadherent cells to convert resident macrophages to a state of C3b receptor-mediated ingestion was not abrogated by the inclusion of polymyxin B in the cocultivation medium. To further characterize these nonadherent cells, different lipopolysaccharide-stimulated cells were obtained by either nylon-wool filtration, depletion of C3b receptor-bearing cells, or depletion of Thy 1.2-positive cells. None of these populations by themselves were capable of inducing resident macrophages to ingest via the C3b receptor, whereas unfractionated cells were. However, coculture of resident macrophages with recombinations of splenic nylon-wool effluent (T cell-enriched) or bound (B cell-enriched) nonadherent cells from lipopolysaccharide-injected mice reconstituted the ability to induce ingestion via the C3b receptor. Taken together, these results suggest that one means by which lipopolysaccharide can induce C3b receptor-mediated ingestion by macrophages is through the cooperative effects of stimulated T and B lymphocytes.
Binding of Salmonella typhimurium lipopolysaccharides to rat high-density lipoproteins
Authors: Munford R S , Hall C L , Dietschy J M
Published: January 2020

These studies were undertaken to investigate the binding of gram-negative bacterial lipopolysaccharides (LPS) to high-density lipoproteins (HDL) of rat plasma. Purified Salmonella typhimurium LPS, intrinsically labeled with [3H]-galactose, bound rapidly in vitro to isolated rat HDL. Maximal binding of LPS to HDL occurred when LPS and HDL were incubated with lipoprotein-free plasma (rho greater than 1.21 g/ml). Since LPS, when purified, form large aggregates, we tested the hypothesis that disaggregation of LPS enhances LPS-HDL binding. We found that calcium chloride (1 mM), an agent which prevents LPS disaggregation, inhibited binding of LPS to HDL by interfering with the modification of LPS by lipoprotein-free plasma. Conversely, sodium deoxycholate (0.15 g/dl), which disaggregates LPS, greatly increased binding of LPS to HDL in the absence of lipoprotein-free plasma. Analysis of labeled LPS by sodium deodecyl sulfate-polyacrylamide gel electrophoresis showed only minor differences in the sizes of LPS molecules before and after binding to HDL, suggesting that chemical modification of LPS is not required for binding. The results provide evidence that disaggregation increases the binding of LPS to HDL.
Positive Cooperativity in the Binding of
Streptococcus sanguis
to Hydroxylapatite
Authors: Nesbitt Warren E. , Doyle Ronald J. , Taylor K. Grant , Staat Robert H. , Arnold Roland R.
Published: January 2020

The adherence of
Streptococcus sanguis
to hydroxylapatite beads has been analyzed by binding isotherms, Langmuir isotherms, and Scatchard plots. For saliva-coated beads, the Scatchard curves contained components with both positive and negative slopes. The results are interpreted as evidence for positive cooperativity in the binding process. Although all Scatchard curves were similar in shape, distinct differences were observed between saliva samples from different individuals. Salivary agglutinins against whole
S. sanguis
cells did not appear to influence the shapes of the curves or the extent of adherence. In addition, different strains of
S. sanguis
yielded similar Scatchard plots. When the binding of
S. sanguis
to buffer-coated hydroxylapatite beads was analyzed by Scatchard plots or binding isotherms, curves were generated which suggested that either direct ligand-ligand or nonspecific interactions were occurring. Hill plots of the adherence data yielded curves with slopes greater than unity for saliva-coated beads, providing additional support for the view that the interactions between
S. sanguis
and the pellicle involve cooperative phenomena. In contrast, a Hill plot for the binding data of
S. sanguis
to buffer-coated hydroxylapatite beads gave a curve with a slope of 0.91 ± 0.07, suggesting negative cooperativity or limited specificity. When adherence data were plotted by the Langmuir method, curves were obtained which could not discriminate between the binding of the bacteria to the hydroxylapatite beads coated with either saliva or buffer. It was also observed that several different proteins and whole saliva tended to inhibit adherence. Scatchard plots, however, describing the binding of
S. sanguis
to the proteincoated beads were unique and revealed possible specific and nonspecific interactions. Scatchard analyses of binding data may be useful in understanding the mechanism(s) of adherence of streptococci to smooth surfaces.
Surface coat variant antigen of Trypanosoma brucei brucei: its clearance from blood and concentration in organs of normal, infected, and immune mice
Authors: Diffley P , Jayawardena A N
Published: January 2020

Experiments were conducted to determine the fate of variant antigen once it was shed from the surface of Trypanosoma brucei brucei. Radioiodinated variant antigen was administered intravenously to normal mice, mice immunized to the homologous variant antigen, and mice infected with an antigenically dissimilar (heterologous) T. brucei brucei variant. The variant antigen was cleared slightly faster in infected and immune animals. Though over 80% of the variant antigen was cleared in all animals within 4 h, traces of radioactivity could be detected in the peripheral blood at 48 h postinjection. At 1 h postinjection, most of the variant antigen had collected in the liver, kidneys, bone marrow, spleen, lungs, thymus, and lymph nodes (listed in the order of decreasing radioactivity). At 24 h, the kidneys, liver, and spleen retained the most radioactivity. The kidneys had 10 to 20 times, the liver had 8 to 10 times, and the spleen had 5 to 7 times more variant antigen than was present in the organs' blood supply. At 48 h postinjection, two-thirds of the radioactivity present at 24 h remained in these tissues. The livers and spleens from infected animals had, on a per gram of tissue weight basis, reduced uptake of the soluble antigen whereas their lungs had an increased uptake. Radioactivity in blood and organs was proved to be associated with protein by electrophoresis/autoradiography and precipitation of radioactive protein of tissue extracts.
Immunological Activities of Purified Preparations of Enterobacterial Common Antigen
Authors: Gannon Patrick J. , Jacobs Diane M. , Marx Arthur , Mayer Hubert , Romanowska Elzbieta , Neter Erwin
Published: January 2020

The immunological activities of three purified preparations of enterobacterial common antigen (ECA) obtained by different procedures were studied. ECA-Ma (method of A. Marx) was from
Salmonella typhimurium
TV149 (Ra mutant), ECA-My (method of H. Mayer) was from
S. montevideo
, and ECA-Ro (method of E. Romanowska) was from
Shigella sonnei
phase I. These preparations, on a weight basis, neutralized similar amounts of ECA antibodies, indicating that the serological activities were comparable. Neither ECA-My nor ECA-Ro elicited specific delayed-type hypersensitivity skin reactions at 24 or 48 h in immunized guinea pigs. ECA-Ma, as well as the nonpurified preparations of the antigens used for immunization, elicited reactions at 24 h but not at 48 h. Thus, ECA-specific delayed-type hypersensitivity was not detected in immunized guinea pigs. Striking differences were noted in the immunogenicity of these antigens, ECA-Ma being highly immunogenic in the rabbit in contrast to ECA-My and ECA-Ro. ECA-Ma was a potent mitogen for guinea pig spleen cells, stimulating high levels of DNA synthesis; ECA-My was only slightly active. The three antigens were mitogenic to spleen cells from both CBA/J and C3H/HeJ mice, although not to the same degree, indicating that this effect is not due to contaminating lipopolysaccharide, since the latter strain of mice is resistant to endotoxin. Since an ECA-Ma extract made from an ECA-negative mutant proved to be mitogenic to murine spleen cells, the mitogenicity is not due to the ECA haptenic determinant. The mitogenic effect is polyclonal in nature, ECA-Ma producing a maximum response on day 3. Thus, the ECA preparations are both B-cell mitogens and polyclonal activators in murine spleen cells. From these studies it is evident that the biological and immunological activities of these purified antigens depend not only on the haptenic determinant but also on associated or bound components of the preparations.
Effects of estradiol and progesterone on Bacteroides melaninogenicus and Bacteroides gingivalis
Authors: Kornman K S , Loesche W J
Published: January 2020

Bacteroides melaninogenicus subsp. intermedius increases in the subgingival microflora during pregnancy. These studies evaluated direct interactions between hormonal steroids and oral Bacteroides species. Resting cell suspensions of pure cultures of plaque organisms were incubated anaerobically with [14C]estradiol and [14C]progesterone. Uptake of labeled compound per microgram of bacterial protein was determined by thin-layer chromatography and liquid scintillation counting. B. melaninogenicus subsp. intermedius and B. melaninogenicus subsp. melaninogenicus took up 2.6 x 10(-4) to 5.4 x 10(-4) mumol of estradiol or progesterone per microgram of cell protein. Minimal steroid uptake was observed with B. gingivalis and five other organisms. Uptake of steroids by B. melaninogenicus subsp. intermedius was temperature dependent and resulted in a labeled product as detected on thin-layer chromatography. Growth curves indicated that intermedius and melaninogenicus subspecies of B. melaninogenicus but not B. gingivalis could substitute progesterone or estradiol for vitamin K, an essential growth factor. Growth of B. melaninogenicus subsp. intermedius in steroids was concentration dependent. Addition of fumarate to resting cells of B. melaninogenicus subspecies as well as B. gingivalis increased steroid uptake by 70 to 500% and resulted in the gas-liquid chromatographic detection of succinate. Cultures given fumarate alone or steroids alone produced no succinate. Steroids appeared to directly interact with the fumarate reductase system and foster the growth of B. melaninogenicus subsp. intermedius. This interaction may be of ecological significance.
Pilus Production, Hemagglutination, and Adhesion by Porcine Strains of Enterotoxigenic
Escherichia coli
Lacking K88, K99, and 987P Antigens
Authors: Awad-Masalmeh M. , Moon H. W. , Runnels P. L. , Schneider R. A.
Published: January 2020

Three strains of enterotoxigenic
Escherichia coli
which adhered, colonized intensively, and caused disease in pig intestine, but which did not produce pili of the K88, K99, or 987P antigen types were designated 3P
−
ETEC. The 3P
−
ETEC caused mannose-resistant hemagglutination, adhered to porcine intestinal epithelial cells in vitro, and produced pili. However, most bacteria taken directly from the intestine of pigs infected with 3P
−
ETEC appeared to be nonpiliated. Two preparations were isolated from the 3P
−
ETEC. One (material A) contained pili, caused mannose-sensitive hemagglutination, and did not inhibit adhesion of whole bacteria to epithelial cells in vitro. The other (material B) had no demonstrable pili, caused mannose-resistant hemagglutination, and blocked ahesion of bacteria to epithelial cells in vitro. Antiserum against an acapsular mutant (K
−
) of one 3P
−
ETEC strain was absorbed to remove antibodies directed against somatic (O) antigen. The absorbed antiserum agglutinated all three 3P
−
ETEC strains grown in the K
−
form at 37°C, but not when they were grown at 18°C. The absorbed antiserum blocked the hemagglutinating activity of material B, but not of material A. It also reacted (via indirect immunofluorescence) with all of the 3P
−
ETEC when they were grown in pig intestine. The results were interpreted to indicate that: (i) the epithelial adhesive and mannose-resistant hemagglutinating activities of the 3P
−
ETEC strains may be mediated by an antigen contained in material B; (ii) this antigen either is not pilus associated or is associated with pili that are not demonstrable by the methods used here; (iii) the 3P
−
ETEC strains produce type 1 pili which do not mediate their adhesion to intestinal epithelium of pigs.
Isolation of heart- and kidney-binding protein from group A streptococci
Authors: Stinson M W , Bergey E J
Published: January 2020

Tritium-labeled, water-soluble components of Streptococcus pyogenes type M6 absorbed to cardiac tissue in vitro. Tissue binding was time dependent, saturable, and reversible. Chromatography of the crude bacterial extract on Bio-Gel P-300 indicated a molecular weight greater than 300,000 for the heart-binding component. Sodium dodecyl sulfate (SDS) dissociated this aggregate into a protein of 18,000 to 20,000 daltons as determined by Sephacryl S-200 chromatography and SDS-polyacrylamide disc gel electrophoresis. The tissue-binding protein was also purified from streptococcal extracts by absorption to immobilized heart components. SDS-polyacrylamide gel electrophoresis of the protein desorbed from tissue revealed a radioactive band of 19,000 daltons. Indirect immunofluorescence tests on cardiac tissue treated with streptococcal extract showed an accumulation of a bacterial antigen on the sarcolemmal sheaths. Streptococcal components also adsorbed to basement membranes of kidney. Antisera prepared to isolated cytoplasmic membranes and water-soluble extracts of S. pyogenes type M6 were the most sensitive reagents for the detection of bacterial components bound to tissue. Antisera prepared to isolated cell walls and to intact bacteria were weakly reactive in these assays.
Biological activities of toxins A and B of Clostridium difficile
Authors: Lyerly D M , Lockwood D E , Richardson S H , Wilkins T D
Published: January 2020

Examination of the biological activities of the two known toxins of Clostridium difficile revealed that one of the toxins (toxin A) elicited a hemorrhagic fluid response in rabbit intestinal loops and a positive fluid response in infant mice. The other toxin (toxin B) did not produce a significant fluid response in either model, although the toxin was more lethal in infant mice. Both toxins elicited erythematous and hemorrhagic skin reactions and increased vascular permeability in rabbit skin.