bluuebunny/crossref_metadata_2025 huggingface dataset:
Lactoperoxidase and thiocyanate protect bacteria from hydrogen peroxide
Authors: Adamson M , Carlsson J
Published: January 2020

Lactoperoxidase and thiocyanate were shown to protect Escherichia coli and three oral streptococcal species from the bactericidal effect of hydrogen peroxide under aerobic conditions. Lactoperoxidase in the absence of thiocyanate was also protective for two of the bacterial species in a dilution medium but potentiated hydrogen peroxide toxicity for the other two under the same conditions. The products of the reaction between hydrogen peroxide and thiocyanate in the presence of lactoperoxidase were not bactericidal except in the case of E. coli, and then only under special conditions. The results demonstrate the effectiveness of lactoperoxidase and thiocyanate in protecting living cells from hydrogen peroxide toxicity. Although the effect on human cells was not examined in this study, extrapolation of these results to the cells of the oral mucosa would suggest an important protective role of lactoperoxidase and thiocyanate against the toxic effects of hydrogen peroxide in the oral cavity.
Mouse protection assay for group B streptococcus type III
Authors: Fleming D O
Published: January 2020

The mucin model for group B Streptococcus (GBS) type III was used to assay the protective effect of sera against a type III challenge in mice. Hyperimmune rabbit sera, prepared by the Lancefield method against the laboratory reference strain (SS620) and a clinical isolate (M732), protected against a lethal challenge with either strain of GBS type III. Absorption of the sera with either of these type III strains removed the protective effect. Neither normal rabbit sera nor heterologous antisera (anti-Ia, SS615) provided protection; however, protection was obtained with pooled human gamma globulin. Sera from adult volunteers were tested to assay protective levels in the mouse model. Human sera enhanced the mouse lethality of the clinical isolate, M732, but not the laboratory reference strain, SS620. Sera from adults vaccinated with type III polysaccharide of GBS were also tested. The murine-mucin-GBS model may be developed as a screening test to measure protective antibody levels in the pre- and postvaccine treatment period. The model may also be used to measure protective antibody in pooled human gamma globulin for use in the passive immunization of high-risk individuals.
Bacillus pumilus in the induction of clindamycin-associated enterocolitis in guinea pigs
Authors: Brophy P F , Knoop F C
Published: January 2020

Antibiotic-associated enterocolitis was induced in guinea pigs by the intraperitoneal injection of clindamycin. The colonic and cecal mucosa and feces of acutely ill animals were cultured under aerobic and anaerobic conditions on 5% sheep blood agar plates and on a selective and differential medium for Clostridium difficile. All morphologically distinct colony types were isolated in pure culture and identified. A sterile cell-free filtrate of each isolate was tested for ability to induce morphological changes in cultured monolayers of mouse adrenal cells. The filtrate of a predominant isolate, Bacillus pumilus, induced an alteration of cellular morphology; the sterile filtrate of other isolates were unreactive. Toxin contained in cell-free filtrates of B. pumilus caused a syndrome identical to clindamycin-associated enterocolitis when injected intracecally into guinea pigs. The toxin had a molecular weight of 6,500 daltons as determined by molecular sieve chromatography and was inactivated with pronase, lipase, and trypsin. The minimal inhibitory concentrations of clindamycin and vancomycin for B. pumilus were 50 micrograms/ml and less than or equal to 0.4 micrograms/ml, respectively.
Ultrastructure of Gram-negative cotton bacteria with different pulmonary toxicities
Authors: Lounatmaa K , Helander I
Published: January 2020

The shedding of outer membrane material was observed by electron microscopy in typical gram-negative cotton bacteria, except Agrobacterium sp. This finding is in accordance with the relative pulmonary toxicities of these bacteria. The presence of capsules did not seem to be correlated with the acute pulmonary toxicity of the bacteria.
Production of Antitoxins to Two Toxins of
Clostridium difficile
and Immunological Comparison of the Toxins by Cross-Neutralization Studies
Authors: Libby Jeffrey M. , Wilkins Tracy D.
Published: January 2020

We prepared antitoxins specific for each of two toxins of
Clostridium difficile
and used these to demonstrate that the toxins are immunologically distinct.
Genetic control of Propionibacterium acnes-induced protection of mice against Babesia microti
Authors: Wood P R , Clark I A
Published: January 2020

Using various strains of inbred mice, we found that Propionibacterium acnes-induced protection against the hemoprotozoan parasite Babesia microti was controlled by a dominant gene(s) not linked to the major histocompatibility gene (H2) complex of mice. P. acnes-induced resistance to infection was not merely an amplification of the normal immune response to B. microti, since innate resistance to infection was controlled by different genes. Expression of the nonspecific protection induced by P. acnes was found to be transferable with cells of bone marrow origin, and it did not necessarily accompany the induction of hepatosplenomegaly. The implication of these results for the understanding of the mechanism of P. acnes-induced protection is discussed.
Serum resistance associated with virulence in Yersinia enterocolitica
Authors: Pai C H , DeStephano L
Published: January 2020

Yersinia enterocolitica strains that exhibited a calcium requirement for growth and autoagglutination at 37 degrees C were invariably virulent in rabbits, causing diarrhea and a high degree of lethality, and were capable of colonizing the intestinal lumen and establishing foci of infection on the Peyer's patches of mice. Strains that had lost the properties of calcium dependency and autoagglutinability were totally avirulent in rabbits and were quickly eliminated from the intestinal lumen and tissues of mice. Virulent and avirulent strains were shown to be equally invasive to HeLa cells. However, the virulent strains were resistant to the bactericidal action of normal serum, and this serum resistance was lost with the loss of virulence. Furthermore, the serum resistance of virulent strains was expressed, as were other properties, when strains were grown at 37 degrees C, but not at 27 degrees C. These results suggest that a virulence factor associated with serum resistance plays an essential role in the pathogenicity of Y. enterocolitica.
Plasmid pattern analysis of Staphylococcal epidermidis isolates from patients with prosthetic valve endocarditis
Authors: Archer G L , Vishniavsky N , Stiver H G
Published: January 2020

The electrophoretic pattern formed by individual bacterial plasmid DNA molecules of differing molecular size was evaluated as an epidemiological marker among isolates of Staphylococcus epidermidis from patients with prosthetic valve endocarditis (PVE). Purified covalently closed circular plasmid DNA was obtained from selected isolates, and 79% of the plasmids were found to be less than 10 megadaltons in size; only these small plasmids were sought in subsequent screening gels. Crude cell lysates obtained by a rapid lysis technique and screened by agarose gel electrophoresis revealed the presence of one or more small plasmids in 54 of 58 (93%) PVE isolates; 79% contained two or more. Among 45 plasmid-containing isolates from cases of sporadic PVE at three institutions there were no identical plasmid patterns, although several isolates differed by a single plasmid. In contrast, among nine isolates from a cluster of cases of PVE in Canada, two groups of three isolates each had identical plasmid patterns. Additional clinical data suggested that these isolates were epidemiologically related. Phage typing distinguished one of the groups with plasmid pattern identity, but not the other, from the three isolates with dissimilar patterns. Plasmid pattern analysis shows promise as an epidemiological marker for clinically important isolates of S. epidermidis.
Effect of estrogens on bacterial adherence to HeLa cells
Authors: Sugarman B , Epps L R
Published: January 2020

Incubating confluent cell culture HeLa cells for 18 h with increasing concentrations of estrogens progressively enhanced the subsequent attachment of a variety of radiolabeled bacteria to the HeLa cells. This effect was not caused by other hormones and was not produced by 1-h incubations of HeLa cells or bacteria with hormones. Estrogens did not similarly affect two other receptor cell lines studied. The addition of metabolic inhibitors showed that this effect of estrogens on HeLa cells was energy dependent and involved protein synthesis. Concurrent incubation of the HeLa cells and estrogens with the antiestrogen nafoxidine blocked the subsequent increase in adherence. These data suggest that estrogen receptors are present in HeLa cells and that hormonally-induced alterations in the synthesis of bacterial receptor sites may modify the capacity of certain cells to bind bacteria.
Susceptibility of bovine macrophages to infectious bovine rhinotracheitis virus infection
Authors: Forman A J , Babiuk L A , Misra V , Baldwin F
Published: January 2020

Infectious bovine rhinotracheitis virus replicated in cultured bovine alveolar macrophages (AM). However, yields of infectious virus were low, with maximum titers approximately 100 times that of the residual inoculum. Immunofluorescence and electron microscopic studies indicated that the majority of macrophages produced viral antigen, but after infection at a multiplicity of 0.1, only 4.1% of AM produced infectious centers. Virus-infected AM culture supernatants possessed interfering activity, probably due to interferon. Incubation of fresh AM with these fluids rendered them refractory to infection. Although AM from infectious bovine rhinotracheitis virus-immune and -susceptible donors were equally permissive and their susceptibility was unaltered by incubation with bacterial lipopolysaccharide, bovine mammary macrophages which were elicited with lipopolysaccharide became nonpermissive when further incubated for 48 h with 1 microgram of lipopolysaccharide per ml. Under these conditions, infected mammary macrophages failed to synthesize viral DNA, and there was reduced synthesis of "late" viral polypeptides.
Cytopathogenicity of Naegleria gruberi for rat neuroblastoma cell cultures
Authors: Marciano-Cabral F M , Bradley S G
Published: January 2020

Amoebae of Naegleria gruberi were cytopathic for cultures of rat neuroblastoma (B-103) cells. N. gruberi grew and destroyed B-103 cells at 30 degrees C. As few as one amoeba inoculated per million B-103 cells resulted in cytopathogenicity after extensive growth of N. gruberi.
Bactericidal Activity of Human Lactoferrin: Differentiation from the Stasis of Iron Deprivation
Authors: Arnold Roland R. , Russell James E. , Champion William J. , Brewer Michael , Gauthier Joseph J.
Published: January 2020

Previous studies have demonstrated a direct iron-irreversible inhibition of a variety of microorganisms by human apolactoferrin. The present study compared the bactericidal effects of lactoferrin on
Streptococcus mutans
with the bacteriostatic effects of iron deprivation. Growth (as determined by change in optical density) and macromolecular synthesis, as determined by incorporation of
14
C-labeled uracil, thymidine, and lysine, were inhibited by incubation of washed exponential-phase
S. mutans
NCTC 10449 with purified human apolactoferrin. Similarly, apolactoferrin inhibited glucose uptake and metabolism. Iron-saturated lactoferrin had no effect on bacterial growth or metabolism and was capable of serving as a source of iron in iron-depleted medium.
S. mutans
failed to grow, and there was no indication of macromolecular synthesis in iron-depleted partially defined medium; however, glucose metabolism continued, though at a reduced rate, and viability was retained for 72 h. There was no detectable metabolism of glucose by cells maintained for 18 h in iron-free medium. Metabolism was restored by transfer of iron-depleted
S. mutans
to iron-complete medium. This was in contrast to the irreversible inhibition by lactoferrin after 1 h of incubation. Inhibition could not be reversed by removal of cell surface-associated lactoferrin as detected by rhodamine isothiocyanate-labeled antilactoferrin. This inhibition of metabolism and rapid loss in viability observed with lactoferrin treatment suggest that lactoferrin has a direct bactericidal effect on
S. mutans
that cannot be attributed to simple iron deprivation.
Gonococci with mutations to low-level penicillin resistance exhibit increased sensitivity to the oxygen-independent bactericidal activity of human polymorphonuclear leukocyte granule extracts
Authors: Daly J A , Lee T J , Spitznagel J K , Sparling P F
Published: January 2020

Gonococci which cause disseminated gonococcal infection are nearly always highly penicillin sensitive, in contrast to many isolates causing uncomplicated gonorrhea. We questioned whether any of the known chromosomal mutations to low-level penicillin resistance might adversely affect virulence. The penA2 locus is known to result in low-level resistance to penicillins, whereas mtr-2 results in nonspecific resistance to a variety of antimicrobial agents. We found that the penA2 and mtr-2 mutations each markedly increased sensitivity of strain FA19 to oxygen-independent killing by human polymorphonuclear leukocyte mixed or isolated azurophilic granule extracts. The penA2 and mtr-2 mutations had no effect on sensitivity to serum antibody and complement. Isogenic opaque or transparent variants of several strains of Neisseria gonorrhoeae were equally resistant to human polymorphonuclear leukocyte mixed granule extract bactericidal systems. There were also no differences in susceptibility of piliated type 1 and nonpiliated type 4 variants to human polymorphonuclear leukocyte mixed granule extracts. Since the penA2 and mtr-2 loci are known to increase the degree of cross-linking of cell wall peptidoglycan, the structure of peptidoglycan apparently affects sensitivity to killing by one or more polymorphonuclear leukocyte azurophilic granule extract bactericidal systems. These observations might explain why gonococci with mutations similar to penA2 and mtr-2 are almost never isolated from patients with disseminated gonococcal infection.
Enhanced Plasmodium falciparum merozoite phagocytosis by monocytes from immune individuals
Authors: Khusmith S , Druilhe P , Gentilini M
Published: January 2020

Phagocytosis of merozoites and schizont-infected erythrocytes prepared from continuous cultures by peripheral blood monocytes from patients with falciparum malaria was investigated with an in vitro assay. Monocytes do ingest merozoites of Plasmodium falciparum, but rarely phagocytose parasitized or nonparasitized erythrocytes in the absence of immune serum. The monocytes from hyperimmune subjects were significantly more efficient in the ingestion of merozoites than were those obtained from sensitized or noninfected subjects. These data indicate, first, that the merozoite rather than the parasitized erythrocyte is the specific target for blood phagocytic cells in human falciparum malaria and, second, that the phagocytosis of merozoites by peripheral blood monocytes increases depending on the level of specific immunity.
Protection against colibacillosis in neonatal piglets by immunization of dams with procholeragenoid
Authors: Fürer E , Cryz S J , Dorner F , Nicolet J , Wanner M , Germanier R
Published: January 2020

Protection against colibacillosis in neonatal piglets was obtained by immunization of pregnant dams with procholeragenoid. Procholeragenoid is a stable high-molecular-weight aggregate of cholera toxin formed during the heating of cholera toxin. Procholeragenoid retained approximately 1% of the toxicity of native toxin as determined in the rabbit ileal loop and Y-1 adrenal cell assays and 5% of the activity in the rabbit skin assay. Immunization of pregnant dams with 50 micrograms of procholeragenoid 5 and 2 weeks before the expected delivery date elicited high titers of antitoxic immunoglobulin G and toxin-neutralizing antibody in both the colostrum and serum. In three independent field trials, immunization with procholeragenoid resulted in a substantial decrease in diarrhea (73% in controls versus 11% in immunized) and death (4.7% in controls versus 0.77% in immunized) in neonatal piglets. The protection rate in the immunized population was approximately 85% for both diarrhea and death. In the following gestation period, reimmunization of dams with a single dose of procholeragenoid (50 micrograms) 2 weeks before delivery elicited titers of antitoxic immunoglobulin G and toxin-neutralizing antibody comparable to those obtained during the primary immunization. The death rate in neonatal piglets (0.86%) was comparable to that seen after immunization during the first gestation period (0.77%). These results indicate that substantial protection of neonatal piglets against colibacillosis can be obtained by immunization of dams with procholeragenoid. Protection was found to be based solely on antitoxic immunity.
Comparison of heat-labile enterotoxins from porcine and human strains of Escherichia coli
Authors: Geary S J , Marchlewicz B A , Finkelstein R A
Published: January 2020

Heat-labile enterotoxins (LTs) from porcine EWD299) and human (H74-114) enterotoxigenic strains of Escherichia coli were isolated by a single-step galactose elution procedure. Although both strains had similar amounts of LT in their whole-cell lysates, H74-114 yielded a smaller quantity of purified LT than did EWD299. Immunodiffusion studies with specific antisera revealed that although the two LTs shared major antigenic determinants each also had unique antigens. Both also had shared and unique specificities in comparison with the cholera enterotoxin (choleragen). Differences also exist in the apparent molecular weights of their B-subunit oligomers (coligenoid) as well as in the B-subunit monomers. The monomer molecular weights are 11,500 for EWD299 porcine LT and 12,700 for H74-114 human LT. The results suggest that either this isolated human LT has a tetrameric coligenoid or it moves differently in sodium dodecyl sulfate gels for other reasons. The A-subunits of both LTs were similar in size (28,000 daltons), and both LTs were activated by mild proteolytic processing. Amino acid analysis showed a threefold increase in the level of tryptophan and two- and fourfold decreases in the levels of glutamic acid and methionine, respectively, in H74-114 LT compared with EWD299 LT. These structural and antigenic differences may prove to be significant in immunoprophylaxis of the cholera-coli family of enterotoxins. Further studies to define the extent of evolutionary drift of these toxins are needed.
Early clearance of pneumococci from the lungs of decomplemented rats
Authors: Rehm S R , Coonrod J D
Published: January 2020

Pneumococcal types which exhibited varying degrees of interaction with the complement system in vitro wee aerosolized into normal and decomplemented rats, and the rate of killing of pneumococci was monitored by serial cultures of whole lung homogenates. The clearance of pneumococci from the alveoli did not correlate with the ability of the pneumococci to be opsonized by complement in vitro. Similarly, rats depleted of complement in the serum and the bronchoalveolar lavage fluid maintained their ability to rapidly inactivate aerosolized pneumococci. These results indicate that the early phase of pneumococcal killing in the alveoli does not require complement and suggest that in the nonimmune host, phagocytosis by alveolar macrophages can be achieved without complement-dependent opsonization or, alternatively, that extracellular factors rapidly inactivate inhaled pneumococci.
Aleutian disease in ferrets
Authors: Porter H G , Porter D D , Larsen A E
Published: January 2020

When 32 antibody-free ferrets were inoculated with the highly mink-virulent Utah-1 strain of Aleutian disease virus (ADV), most developed ADV antibody starting 15 days after infection, but the antibody titers were much lower than those seen in mink. Relatively small amounts of ADV were demonstrated in CRFK cell culture, using ferret spleen and lymph node homogenates only 4 to 10 days after experimental infection, but low-level viral persistence for 180 days was shown by mink inoculation. The ferrets inoculated with the Utah-1 strain of ADV did not develop elevated gamma globulin levels, but did have mild tissue lesions. Forty-two percent of a group of 214, approximately 1-year-old, recently pregnant, female ferrets were found to have antibody to ADV. An analysis of the serum proteins of the ferrets with ADV antibody showed that they had a significant, but mild, elevation of their serum gamma globulin. Serial ferret-to-ferret transmission of a ferret strain of ADV by inoculation of spleen homogenates was demonstrated, and some of these ferrets developed liver lesions. Mink inoculated with ferret ADV made antibody, but did not develop hypergammaglobulinemia or tissue lesions. Although both ferret and mink strains of ADV replicate and persist in the ferret, they fail to cause severe disease of the type usually seen in the closely related mink. Mink and ferret ADV strains appear to be biologically distinct.
Maturity as a critical determinant of resistance to fungal infections: studies in murine blastomycosis
Authors: Brass C , Stevens D A
Published: January 2020

Marked resistance of 9-week-old mice as compared to that of 5-week-old mice was demonstrated after pulmonary challenge with three strains of Blastomyces dermatitidis of various virulences. Quantitative studies with graded doses of the strain that was intermediate in virulence indicated that the difference in resistance between the two age groups was 1,000-fold. Acquisition of resistance appeared to be gradual between the ages of 5 and 9 weeks. Maturational differences among individual mice appeared to be most crucial at 5 weeks of age. With two fungal strains, susceptibility of the younger mice was also demonstrated after intraperitoneal challenge; with one of these strains, the differences between the two groups of mice were much smaller, suggesting that maturation of defenses in the peritoneal cavity may develop faster. Studies with serial sacrifice of different groups of mice given pulmonary challenges (of comparable amounts) indicated that the differences are not due to the amount of challenge reaching the lungs or its clearance. The infection-limiting effect in the lungs of older mice occurred within 4 days after challenge. These differences in resistance over this narrow age interval appear to be unique; resistance appears to occur later than resistance to other infectious agents and at a time when most murine immune functions have matured. This model and these observations provide an opportunity for further studies of the mechanism of resistance and are relevant to clinical observations of susceptibility of infants and children to deep mycoses.
Salmonella and arizona infections of alimentary and reproductive tracts of Panamanian lizards
Authors: Kourany M , Telford S R
Published: January 2020

Salmonella and Arizona spp. were isolated from various sites of the digestive and reproductive tracts of lizards. The finding that bacteria in the oviducts and in the internal contents of oviductal eggs were of the same serotype raises the possibility that transovarian bacterial transmission in lizards occurs in nature.
Plasmid-mediated transformation of Streptococcus mutans
Authors: Kuramitsu H K , Long C M
Published: January 2020

Streptococcus mutans GS-5 was transformed to erythromycin resistance with streptococcal plasmid pVA736. Transformation frequencies were higher with plasmids reisolated from transformed GS-5 cells relative to plasmid originally derived from S. sanguis Challis.
Receptor in group C and G streptococci detects albumin structures present in mammalian species
Authors: Widebäck K , Seal U S , Kronvall G
Published: January 2020

The presence of albumin structures with the capacity to bind to a surface receptor in group C and G streptococci was studied in serum samples from 45 mammalian species representing 15 different orders, using an inhibition assay. The ability of animal sera to inhibit the uptake of radiolabeled human serum albumin by the streptococci indicated the presence of such albumin structures. Positive reactions were found in species of most orders tested, with Marsupialia as a notable exception. All Carnivora sera tested were strongly positive. In some orders such as Artiodactyla both positive and negative species were identified. Serum samples from 62 bird species representing 15 orders and from 5 fish species were also tested in the inhibition assay. None of these serum samples was capable of inhibiting the uptake of human serum albumin by streptococci. Some differences were also noted in the results obtained with group C and G streptococci from human and bovine sources, respectively, indicating the presence of two types of receptors. The present studies suggest a phylogenetic origin of albumin structures with affinity for the streptococcal receptor to a period after the divergence of Marsupialia from the other mammalian orders.
Differences in phagocytosis and killing by alveolar macrophages from humans, rabbits, rats, and hamsters
Authors: Nguyen B Y , Peterson P K , Verbrugh H A , Quie P G , Hoidal J R
Published: January 2020

Phagocytosis and killing by alveolar macrophages from humans, rabbits, rats, and hamsters, were compared in vitro. In the absence of serum opsonins, human alveolar macrophages could phagocytize Staphylococcus aureus Cowan I (protein A positive), but not S. aureus EMS (protein A negative) or Pseudomonas aeruginosa MN. In contrast, rabbit, rat, and hamster alveolar macrophages did not phagocytize S. aureus Cowan I or other nonopsonized bacteria. Human alveolar macrophages, but not other species, stained positively with fluorescein isothiocyanate-conjugated protein A. When opsonized bacterial were studied, phagocytosis by human, rabbit, and hamster alveolar macrophages was found to be mediated by both Fc and C3 receptors. However, only Fc receptor-mediated phagocytosis of bacteria was demonstrated for rat alveolar macrophages. Differences were also found in the kinetics of bacterial killing by alveolar macrophages from different species. Human and rabbit alveolar macrophages rapidly killed opsonized S. aureus Cowan I. However, bacterial killing by hamster alveolar macrophages proceeded at a slower rate, and rat alveolar macrophages completely failed to kill S. aureus. These significant differences in the function of alveolar macrophages from four different species emphasize the need to document the appropriateness of animal models before using them to predict the biological activities of human alveolar macrophages.
Deficient autolytic enzyme activity in antibiotic-tolerant lactobacilli
Authors: Kim K S , Morrison J O , Bayer A S
Published: January 2020

To define the mechanism(s) of penicillin tolerance in lactobacilli, one nontolerant and two tolerant strains were examined for autolytic enzyme activity. When incubated with 14C-labeled cell wall preparations, autolysin extracts of tolerant lactobacilli released significantly less radioactivity than did extracts of nontolerant lactobacilli (p less than 0.02). These differences in the release of radioactivity by nontolerant and tolerant strains were maximal during the logarithmic growth phase. Moreover, this activity was greatest at pH 8, was heat labile, and was inhibited by the addition of magnesium, suggesting characteristics of an enzyme. This study illustrates that autolytic enzyme activity is deficient in strains of antibiotic-tolerant lactobacilli and suggests that this may be partially responsible for the delayed killing effect of penicillins against such strains.
Chemotaxis of purified human monocytes in vitro: lack of accessory cell requirement
Authors: Falk W , Leonard E J
Published: January 2020

This study was undertaken to determine whether cell cooperation, either among monocytes or between monocytes and lymphocytes, is a prerequisite for monocyte chemotactic responsiveness. We compared Ficoll-Hypaque-separated mononuclear cells and a preparation of 99% pure monocytes obtained by chemotaxis in a newly designed separation chamber. Monocytes of both preparations migrated to chemoattractants without a lag phase, and no further increase in migrated cells was observed after 70 min. The cell dose-response was linear for both preparations over a wide range of cell concentrations in the cell input well of the chemotaxis chamber, suggesting that no monocyte-monocyte interaction was required. Since only 20 to 60% of the monocytes purified by chemotaxis migrated a second time, the possibility of a requirement for an accessory cell was tested. The addition to purified monocytes of several different mononuclear cell preparations comprising lymphocytes or nonmigrating monocytes had no effect on monocyte migration. These experiments show that normal human blood monocytes in vitro do not require stimuli from other cells to respond to chemoattractants. Their behavior is profoundly different from that of mouse peritoneal macrophages, which exhibit a time lag in vitro before migration toward an attractant and become more responsive with either increasing cell concentration or addition of purified lymphocytes.
Genetic control of responses to Trypanosoma cruzi in mice: multiple genes influencing parasitemia and survival
Authors: Wrightsman R , Krassner S , Watson J
Published: January 2020

Inbred strains of mice can be divided into two groups based on the level of parasitemia which develops after injection with 10(3) trypomastigotes of Trypanosoma cruzi (Peru). Strains which developed parasitemias of greater than 10(7) trypomastigotes per ml by day 17, including C3H/HeJ, BALB/c, and CBA/N mice, were termed high parasitemia strains. Low parasitemia strains, including C57BL/6J and DBA/2J mice, developed parasitemias of less than 5 x 10(6) trypomastigotes per ml by day 17 of infection. Congenic mice from C57BL/10J, C57BL/6J, and BALB/c backgrounds which differed at the H-2 region were injected with 10(3) trypomastigotes to determine the effect of the H-2 locus on response to infection. The H-2 locus had no effect on the level of parasitemia attained during infection. However, one strain, B10.S (H-2s), was unusual in that most of the mice survived infection. The results of infection of F1 hybrid progeny with T. cruzi (Peru) suggest that the low parasitemia response in inherited in a dominant manner and that survival may be influenced by several other genes. The response to T. cruzi infection in inbred mice, as measured by parasitemia and survival time, was influenced by several genes. One or more genes, located outside the H-2 region, were involved in regulating the level of parasitemia reached during infection. Another H-2-linked gene(s) was involved in survival of the infection and appeared to be unique to the H-2s haplotype.
Murine respiratory mycoplasmosis in F344 and LEW rats: evolution of lesions and lung lymphoid cell populations
Authors: Davis J K , Thorp R B , Maddox P A , Brown M B , Cassell G H
Published: January 2020

By comparison of two strains, LEW and F344, which are known to differ in susceptibility to Mycoplasma pulmonis respiratory disease, it was shown that differences in lesion severity and progression were associated with changes in lung lymphocyte populations. Lung lesions in LEW rats developed earlier after infection, became more severe, and were characterized by continued proliferation of all classes of lymphoid cells, T lymphocytes, B lymphocytes, and plasma cells, throughout the 120-day observation period. In contrast, lymphoid proliferation in F344 rats reached a plateau at 28 days and was restricted to an increase in T lymphocytes, immunoglobulin A (IgA)-bearing B lymphocytes, and IgA and IgG plasma cells. Although approximately 10 times as many IgG B cells and 4 times as many IgG plasma cells were found in infected LEW rats as compared with F344 rats, the specific anti-M. pulmonis IgG response in the two strains was roughly parallel. The same relationships held true, although to a lesser extent, for specific IgA antibody responses and cellular responses. Whereas lung lesions showed a tendency to resolve in F344 rats by 120 days, severe lesions persisted in LEW rats. The disparity between the cellular response and specific antibody response, the seemingly uncontrolled lymphocyte proliferation in LEW rats, and the mitogenic potential of M. pulmonis suggest that differences between LEW and F344 rats in lung lesion severity and progression are related to differences in the degree of nonspecific lymphocyte activation in the two strains, an imbalance in regulation of lymphocyte proliferation in LEW rats, or both.
Mycoplasma arthritidis-induced ocular inflammatory disease
Authors: Thirkill C E , Gregerson D S
Published: January 2020

Mycoplasma arthritidis was demonstrated to incite experimental conjunctivitis and uveitis in Swiss Webster mice which have a known susceptibility to the arthritis customarily associated with infection by this mycoplasma. The initial symptom of ocular involvement was conjunctivitis, which appeared as early as 1 day after intravenous injection with viable culture concentrates of M. arthritidis. By day 2, histological analysis showed intraocular localized inflammatory reactions that were confined primarily to the anterior portion of the uvea and produced results which were compatible with those seen in iridocyclitis. Serological assays of the titer and the class of antibodies involved in the early humoral immune response to infection confirmed the predominance of immunoglobulin G (IgG) concentrations over IgM concentrations that was described by others (Cole et al., Infect. Immun. 4:431-440, 1971) and revealed significant titers of the IgG2a and IgG2b subclasses of complement-fixing antibodies. The rapid onset of acute conjunctivitis, together with the early appearance of immunoglobulins of the IgG class, suggests that the M. arthritidis-infected Swiss Webster mice may have experienced an anamnestic response to the mycoplasma antigens. These observations introduce a new animal model for the study of mycoplasma-induced experimental uveitis and conjunctivitis, which are demonstrated here to accompany a disseminated systemic disease process.
Use of indomethacin to demonstrate enterotoxic activity in extracts of Entamoeba histolytica trophozoites
Authors: Udezulu I A , Leitch G J , Bailey G B
Published: January 2020

The present study was designed to develop and characterize animal models for the assay of enterotoxic activity in extracts of Entamoeba histolytica trophozoites. Marked water and electrolyte secretion occurred in both in vivo rabbit ileal loops and rat colon loops exposed to clarified sonic fluids of E. histolytica strain HM-1 trophozoites (10(6)/ml) when the animals were first administered indomethacin (0.1 mg/kg). No effect on intestinal absorption was observed in animals exposed to Entamoeba extracts alone or after administration of a lower (0.01 mg/kg). No effect on intestinal absorption was observed in animals exposed to Entamoeba extracts alone or after administration of a lower (0.01 mg/kg) dose of indomethacin. Higher doses (greater than or equal to 1 mg/kg) of indomethacin inhibited extract-induced secretion. No enterotoxic activity was detected with or without indomethacin, using extracts from the nonpathogenic E. histolytica-like Laredo strain, even at 10-fold-higher cell concentrations. The HM-1 enterotoxic activity was heat labile. Prior exposure of the loop lumen to fetuin (100 micrograms/ml) blocked the secretory response to subsequent HM-1 extract exposure, but postexposure of the loop to fetuin did not block secretion that had already been established by the amoeba extract. No histological changes were seen associated with the amoeba extract-induced secretion. The data suggest that E. histolytica HM-1 strain elaborates an enterotoxic activity capable of causing consistent secretion in the mammalian intestine that has had its mucosal cytoprotection impaired by indomethacin.
Experimental otitis media in gerbils and chinchillas with Streptococcus pneumoniae, Haemophilus influenzae, and other aerobic and anaerobic bacteria
Authors: Fulghum R S , Brinn J E , Smith A M , Daniel H J , Loesche P J
Published: January 2020

To ascertain the usefulness of Mongolian gerbils as an inbred model for otitis media, 52 Mongolian gerbils (Meriones unguiculatus, strain MONT/Tum) were compared with 26 chinchillas (Chinchilla laniger) for susceptibility to Streptococcus pneumoniae type 3. Haemophilus influenzae type b, and a polymicrobic culture including anaerobes (Streptococcus intermedius, Propionibacterium acnes, Staphylococcus epidermidis, and Corynebacterium sp.). Organisms were inoculated percutaneously into the superior chamber of the middle ear bulla. The gerbils and chinchillas shared similar susceptibilities and responses to the inoculated organisms as determined by X-ray, otoscopic, histopathological, and microbiological determinations at 5 to 7 days. Koch's postulate studies proved the role of S. pneumoniae and H. influenzae in the pathology found in both animal models. The animals were also susceptible to the polymicrobic culture, although the relative virulence of the individual members of this mixture was low, suggesting that these species potentiated as a polymicrobic mixture. The Corynebacterium sp. appeared to elicit the greatest histopathological response in chronic (8-week) studies in gerbils. The gerbils were found to be useful as an alternative animal model for the study of otitis media of bacterial etiology.
Susceptibility of radiation chimeras to Trypanosoma cruzi
Authors: Trischmann T M
Published: January 2020

Reciprocal bone marrow transfers were performed with C3H/HeJ mice, which are susceptible to infection with the Brazil strain of Trypanosoma cruzi, and resistant F1 (C3H/HeJ X C57BL/6J) mice. Mice reconstituted after lethal irradiation with syngeneic bone marrow displayed the resistance phenotype of the strain used, but neither C3H mice reconstituted with F1 bone marrow cells nor F1 mice reconstituted with C3H bone marrow cells survived challenge. Resistance to T. cruzi appears to be dependent upon factors associated both with host background and with bone marrow-derived cells.
Serotypes of enterotoxigenic Escherichia coli in Thailand and the Philippines
Authors: Echeverria P , Orskov F , Orskov I , Plianbangchang D
Published: January 2020

The serotypes of 386 enterotoxigenic Escherichia coli (ETEC) isolated from 82 individuals with and without diarrhea in Thailand and the Philippines were determined. The 136 strains producing both heat-labile toxin (LT) and heat-stable toxin (ST) belonged to 12 different O serogroups; however, 83% (113/136) were of one of four serogroups (O6, O8, O25, and O78), and 76% of (104/136) belonged to one of seven O:K:H serotypes. Only 14% (28/196) of LT-only-producing ETEC belonged to serogroups most common among LT and ST strains, and these 196 strains belonged to 35 different O:K:H serotypes. Three O serogroups (O20, O27, and O78) accounted for 94% (52/54) of strains producing only ST. Although only 4% (2/54) of ST-only ETEC belonged to the seven serotypes most commonly found among strains which produced LT and ST, 85% of ETEC belonged to three other serotypes, O20:K?:H21, O27:K?:H7, and O78:H-. A total of 46% (37/80) of ETEC of serotypes O6:H16, O8:H9, O25:H42, and O78:H12 were resistant to two or more antibiotics in comparison to 68% (208/306) of ETEC of other serotypes (P less than 0.001). In Thailand and the Philippines, E. coli which produced LT and ST or ST alone, but not those which produced LT alone, were restricted in their O:K:H serotypes.
Pathogenesis of herpes simplex labialis: correlation of vesicle fluid interferon with lesion age and virus titer
Authors: Spruance S L , Green J A , Chiu G , Yeh T J , Wenerstrom G , Overall J C
Published: January 2020

Of 51 patients with herpes simplex labialis, 50 had detectable interferon (IFN) in samples of lesion vesicle fluid. The median titer of vesicle fluid IFN was 8,200 U. and the range of values was 400 to 63,600 U. The amount of vesicle fluid IFN was correlated with lesion age (r = 0.32, P = 0.024) and vesicle fluid virus titer (r = 0.59, P = 0.00004), but not with the clinical severity of the disease. The presence of vesicle fluid IFN (1,500 to 28,600 U) in 15 lesions less than 12 h old emphasizes the need for early treatment in studies of antiviral agents for herpes simplex labialis.
Purification and Biological Characterization of Shiga Toxin from
Shigella dysenteriae
1
Authors: Brown J. Edward , Griffin Darrell E. , Rothman Sara W. , Doctor B. P.
Published: January 2020

Shiga toxin has been purified in milligram quantities to near homogeneity from cell lysates of
Shigella dysenteriae
1 strain 3818-0. Purification involved an initial ultracentrifugation, ammonium sulfate fractionation, chromatography on DEAE-cellulose and carboxymethyl cellulose, gel filtration, and preparative isoelectric focusing in sucrose gradients. The purified toxin was resolved by discontinuous polyacrylamide gel electrophoresis into a major cytotoxic protein band and a closely migrating, cytotoxic protease-nicked minor band. Antiserum generated by immunization with glutaraldehyde-inactivated toxin was shown to be monospecific against
S. dysenteriae
cell lysates. This highly purified toxin was cytotoxic to HeLa cells, enterotoxic in rabbit ileal loops, and lethal to mice. Monospecific antiserum to the toxin neutralized completely these toxin activities in both purified toxin preparations and crude shigella cell lysates.
Genomic and phenotypic analyses of Mycoplasma pneumoniae strains
Authors: Chandler D K , Razin S , Stephens E B , Harasawa R , Barile M F
Published: January 2020

Mycoplasma pneumoniae strains PI-1428, M129, B176, FH, and MAC were analyzed for homology by DNA-DNA hybridization, thermal elution midpoints of the DNA-DNA heteroduplexes, DNA cleavage patterns with restriction endonucleases, and protein gel electrophoretic profiles. These properties were compared with biological assays, such as antigenic reactivity with reference antisera in the growth inhibition and metabolic inhibition tests, as well as the ability to attach to human WiDr cell cultures. The avirulent, nonhemadsorbing strain B176 could be differentiated from the others by diminished attachment capacity to WiDr cells and by slightly reduced DNA homology. The other strains appeared to be identical when examined by these procedures. No significant differences were detected among any of the strains by the metabolic inhibition or growth inhibition tests. The DNA cleavage patterns of the five strains were also similar, although strains FH and MAC differed from the other three strains in a few bands. These results demonstrate that these five strains are similar and that the species M. pneumoniae is remarkably homogeneous.
Tissue localization of complement component 3 receptor-bearing cells in lymphoid tissue after injection with complete Freund adjuvant
Authors: Okuyama H , Kobayashi S , Fujita M , Yasumizu R , Morikawa K
Published: January 2020

Localizations of complement component 3 (C3) receptor (C3R)-bearing cells in lymph nodes obtained from normal guinea pigs or from guinea pigs inoculated with complete Freund adjuvant were examined by staining with fluorescein-labeled anti-guinea pig C3 antibody after treatment with aggregated rabbit immunoglobulin M bound with guinea pig complement. In normal lymph nodes, a small number of C3R-positive cells were observed in the cortical and medullary areas. Non-granulomatous lymph nodes from complete Freund adjuvant-inoculated animals showed a number of C3R-positive lymphocytes in a mantle zone of the secondary follicles between the follicles and medullary cords, whereas in the paracortical areas and germinal centers, only a few positive cells were scattered. Long-lasting existence of positive cells was seen in the epithelioid cell granuloma, although the staining patterns were different from those of the lymphocytes. The appearance of a number of C3R-bearing lymphocytes in lymph nodes from complete Freund adjuvant-inoculated animals might be an expression of adjuvant activity.
Mammary gland contamination as a means of establishing long-term gastrointestinal colonization of infant mice with Candida albicans
Authors: Hector R F , Domer J E
Published: January 2020

Infant outbred CD-1 mice were infected intragastrically with Candida albicans by inoculating the mammary glands of the lactating mothers with viable blastospores and allowing the infants to suckle. Levels of colonization were determined by quantitative cultures of stomachs and selected organs at various intervals up to 6 weeks after infection. The results demonstrate that a high percentage of infant mice can be colonized in this manner and that the colonization is of long duration. Although systemic spread of the yeast to other visceral organs did occur, the numbers of yeasts recovered were minimal.
Failure to detect conventional enterotoxins in classical enteropathogenic (serotyped) Escherichia coli strains of proven pathogenicity
Authors: Robins-Browne R M , Levine M M , Rowe B , Gabriel E M
Published: January 2020

Ammonium sulfate-precipitated supernatants of classical enteropathogenic Escherichia coli strains were negative when investigated for enterotoxin production in rabbit ligated ileal loops, rabbit skin vascular permeability factor tests, suckling mice, and Y-1 adrenal cells. They also failed to stimulate guanylate cyclase activity in homogenates of rabbit, rat, and infant mouse intestines. Furthermore, DNA from enteropathogenic E. coli lacked sequences that encode heat-labile and heat-stable enterotoxins. These studies fail to show conventional enterotoxin synthesis by classical enteropathogenic E. coli.
Generation of chemotactic factors by Rhizopus oryzae in the presence and absence of serum: relationship to hyphal damage mediated by human neutrophils and effects of hyperglycemia and ketoacidosis
Authors: Chinn R Y , Diamond R D
Published: January 2020

As our previous studies had shown that human neutrophils could kill Rhizopus oryzae hyphae in vitro, interactions of these hyphae with neutrophils and serum were further explored. Heated or fresh normal human sera suppressed hyphal metabolic activity as determined by [14C]uracil uptake, but severe ketoacidosis (8 X 10(-3) M beta-hydroxybutyric acid plus 2 X 10(-3) M acetoacetic acid at pH 7.0) negated this effect. Hyperglycemia (500 mg/dl) and severe ketoacidosis did not affect damage to hyphae by human neutrophils. Hyphae generated factors from sera which induced comparable chemotactic responses by neutrophils obtained from both normal and diabetic subjects, using a leading front assay performed in modified Boyden chambers. Zymosan-stimulated neutrophil chemotaxis was marginally depressed only by the combined elevation of both glucose (500 mg/dl) and ketoacids (10(-2)M) irrespective of pH (7.0 to 7.4), but not by any of these factors alone. Protein-containing supernatants from live or killed hyphae were chemotactic in the absence of serum based upon "checkerboard" assays varying the concentrations of hyphal supernatants above and below filters in the Boyden chambers. The supernatant-induced chemotactic response by neutrophils from diabetic subjects was minimally less than that of normal neutrophils (P less than 0.05). These findings indicate that R. oryzae hyphae can generate chemotactic factors which might prove to influence the inflammatory response to infections in vivo, and that severe hyperglycemia and ketoacidosis might affect interaction between the host and invading hyphae in mucormycosis.