bluuebunny/crossref_metadata_2025 huggingface dataset:
Paper Mill Effluent Decolorization by Fifty
Streptomyces
Strains
Authors: Hernández Manuel , Rodríguez Juana , Soliveri Juan , Copa José L. , Pérez María I. , Arias María E.
Published: January 2020

Fifty actinomycete strains isolated from lignocellulosic substrates were examined for the ability to remove the color from a paper mill effluent obtained after semichemical alkaline pulping of wheat straw.
Streptomyces
sp. strains UAH 15, UAH 23, UAH 30, and UAH 51 were selected for their ability to decolorize the effluent in a liquid medium containing 1% (wt/vol) glycerol, 0.2% (wt/vol) ammonium sulfate, and 80% (vol/vol) effluent. The highest levels of decolorization achieved after the strains grew were 60 to 65%. Strains UAH 30 and UAH 51 were selected for further study because of their different patterns of effluent decolorization during growth. Fractionation of the decolorized effluent by gel permeation chromatography demonstrated that there were reductions in the levels of absorbance of the high- and medium-molecular-weight compounds. These fractions were mainly responsible for the color of the effluent, while the last fractions, the low-molecular-weight compounds, could have been responsible for the residual color of the decolorized effluent. Thin-layer chromatography revealed significant differences among the patterns of bands corresponding to the acidified supernatants obtained after precipitation of alkali-lignin from the effluent samples decolorized by different
Streptomyces
strains.
Hydrostatic Pressure and Electroporation Have Increased Bactericidal Efficiency in Combination with Bacteriocins
Authors: Kalchayanand N. , Sikes T. , Dunne C. P. , Ray Bibek
Published: January 2020

We report here that both ultrahigh hydrostatic pressure (UHP) and electroporation (EP) induced sublethal injury to bacterial cells surviving the treatments. The injured cells of both gram-positive and -negative bacteria became sensitive to the bacteriocins pediocin AcH and nisin. Bacteriocins in combination with either UHP or EP have greater antibacterial effectiveness than UHP or EP alone.
Optimization of an Escherichia coli formate dehydrogenase assay for selenium compounds
Authors: Tschursin E , Wolf W R , Lacroix D , Veillon C , Patterson K Y
Published: January 2020

A microbiological assay to detect different chemical compounds of selenium for potential future use in the study of the distribution of these chemical forms in foods is being developed. This assay is based on the detection, by infrared analysis, of CO2 in a culture of Escherichia coli when the bacteria are grown in the presence of various selenium compounds. The CO2 production is the result of selenium-dependent formate dehydrogenase activity, which catalyzes oxidation of formic acid produced during glucose metabolism. Smooth response curves were generated over several orders of magnitude for selenocystine, selenite, and selenomethionine. The assay detects selenium concentrations (above background) as low as 1.5 nM for selenocystine and selenite and 4 nM for selenomethionine in minimal medium. Detection of selenomethionine was enhanced (to a sensitivity of 1.5 nM) by the addition of methionine to minimal medium and was enhanced even further (to a sensitivity of 0.8 nM) by the addition of a defined mixture of amino acids. Selenomethionine could be assayed in the presence of an amino acid concentration which is proportional to the amino acid/elemental selenium ratio found in a wheat gluten reference material (NIST SRM 8418). This implies that the assay can detect selenium compounds in a variety of foods at low concentrations, avoiding the background CO2 production caused by high concentrations of non-selenium-containing amino acids. The observation that methionine enhanced selenomethionine availability for formate dehydrogenase synthesis supports studies in animals demonstrating that methionine controls selenomethionine incorporation into selenoenzymes.(ABSTRACT TRUNCATED AT 250 WORDS)
Evidence for phage-mediated gene transfer among Pseudomonas aeruginosa strains on the phylloplane
Authors: Kidambi S P , Ripp S , Miller R V
Published: January 2020

As the use of genetically engineered microorganisms for agricultural tasks becomes more frequent, the ability of bacteria to exchange genetic material in the agricultural setting must be assessed. Transduction (bacterial virus-mediated horizontal gene transfer) is a potentially important mechanism of gene transfer in natural environments. This study investigated the potential of plant leaves to act as surfaces on which transduction can take place among microorganisms. Pseudomonas aeruginosa and its generalized transducing bacteriophage F116 were used as a model system. The application of P. aeruginosa lysogens of F116 to plant leaves resulted in genetic exchange among donor and recipient organisms resident on the same plant. Transduction was also observed when these bacterial strains were inoculated onto adjacent plants and contact was made possible through high-density planting.
Purification and Characterization of
Aeromonas caviae
ME-1 Xylanase V, Which Produces Exclusively Xylobiose from Xylan
Authors: Kubata Bruno Kilunga , Suzuki Tohru , Horitsu Hiroyuki , Kawai Keiichi , Takamizawa Kazuhiro
Published: January 2020

A xylanase, which produces exclusively xylobiose from oat spelt and birch xylans, was isolated from the culture medium of
Aeromonas caviae
ME-1. The enzyme (xylanase V) was purified by ammonium sulfate fractionation, hydrophobic interaction, and ion-exchange and gel filtration chromatographies. The homogeneity of the final preparation was demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and agarose gel electrofocusing. The molecular mass and isoelectric point of the xylanase were 46 kDa and 5.4, respectively. Xylanase V had a maximum activity at a pH of 6.8 and at a temperature between 30 and 37°C. It was relatively stable at a pH between 5.0 and 8.6 and a temperature between 25 and 37°C. When soluble birch xylan was used as the substrate, the enzyme had a
K

m

and
V
max
of 2 mg/ml and 182 μmol of xylose equivalent liberated · min
-1
· mg of protein
-1
, respectively. By the action of xylanase V on xylans (from oat spelt and birch), only one product corresponding to xylobiose was observed by thin-layer chromatography. The xylanase V putative product was confirmed to be xylobiose by acid and enzymatic hydrolyses. The xylanase had neither β-xylosidase, α-
l
-arabinofuranosidase, cellulase, nor β-1,3-xylanase activities. Xylotriose was the shortest substrate which the enzyme could attack. These findings suggest that xylanase V is a novel enzyme that cleaves a xylobiose unit from one of the ends of xylans, probably by an exomechanism.
Characteristics of beta-lactamase-inhibiting proteins from Streptomyces exfoliatus SMF19
Authors: Kim M K , Lee K J
Published: January 2020

Streptomyces exfoliatus SMF19 produced two types of extracellular beta-lactamase-inhibiting proteins, 48 (beta LIP-I) and 33 (beta LIP-II) kDa. The inhibition mode of beta LIP-I on Bacto Penase and benzylpenicillin as substrates was uncompetitive (i.e., both Km and Vmax were changed), while that of beta LIP-II was noncompetitive (i.e., only Vmax was changed). The inhibition constants of beta LIP-I and beta LIP-II were 0.62 x 10(-4) and 2.74 x 10(-1) mumol, respectively. The N-terminal amino acid sequence of beta LIP-I was NH3-*-S-T-V-F-D-L-V-*-L-G, and that of beta LIP-II was NH3-D-F-*-V-F-D-L-E-A-T-D-E.
Comparison of the taxonomy, serology, drug resistance transfer, and virulence of Citrobacter freundii strains from mammals and poikilothermic hosts
Authors: Toranzo A E , Cutrín J M , Roberson B S , Núñez S , Abell J M , Hetrick F M , Baya A M
Published: January 2020

In this study, the phenotypic, antigenic, and virulence characteristics of 32 Citrobacter freundii strains of fish, human, and veterinary origin were comparatively analyzed. In addition, the spread of drug resistance factors by conjugation was investigated. Regardless of the source of isolation, the strains exhibited variable reactions mainly for arginine dihydrolase, ornithine decarboxylase, and fermentation of sucrose, melibiose, amygdalin, and salicin. Total fatty acid methyl ester analysis by gas chromatography proved to be useful for an intratypic differentiation within the C. freundii strains studied. In fact, although all of the isolates exhibited similar fatty acid methyl ester profiles, significant differences in the major fatty acids 16:1 and 16:0 and in the 17:0 delta region were observed between the isolates from salmonids and the remaining strains. Serological studies using agglutination tests, analysis of lipopolysaccharides (LPS), and the corresponding immunoblots with 13 antisera indicated a great antigenic diversity among the strains. Common LPS patterns were shared only by some isolates showing high cross-agglutination titers. In contrast, although all strains exhibited very similar surface protein patterns, only two common outer membrane proteins of 54 and 58 kDa were immunologically related. Infectivity trials performed in mice and rainbow trout indicated that all of the C. freundii strains were not pathogenic for mice (50% lethal dose of > 5 x 10(7)). Although the isolates displayed a low degree of virulence for trout, inoculated strains were always recovered from the survivors in pure culture.(ABSTRACT TRUNCATED AT 250 WORDS)
Cesium Accumulation and Growth Characteristics of
Rhodococcus erythropolis
CS98 and
Rhodococcus
sp. Strain CS402
Authors: Tomioka Noriko , Uchiyama Hiroo , Yagi Osami
Published: January 2020

Growth and cesium accumulation characteristics of two cesium-accumulating bacteria isolated from soils were investigated.
Rhodococcus erythropolis
CS98 and
Rhodococcus
sp. strain CS402 accumulated high levels of cesium (approximately 690 and 380 μmol/g [dry weight] of cells or 92 and 52 mg/g [dry weight] of cells, respectively) after 24 h of incubation in the presence of 0.5 mM cesium. The optimum pH for cesium uptake by both
Rhodococcus
strains was 8.5. Rubidium and cesium assumed part of the role of potassium in the growth of both
Rhodococcus
strains. Potassium and rubidium inhibited cesium accumulation by these
Rhodococcus
strains. It is likely that both
Rhodococcus
strains accumulated cesium through a potassium transport system.
Influence of substrate diffusion on degradation of dibenzofuran and 3-chlorodibenzofuran by attached and suspended bacteria
Authors: Harms H , Zehnder A J
Published: January 2020

Dibenzofuran uptake-associated kinetic parameters of suspended and attached Sphingomonas sp. strain HH19k cells were compared. The suspended cells were studied in a batch system, whereas glass beads in percolated columns were used as the solid support for attached cells. The maximum specific activities of cells in the two systems were the same. The apparent half-maximum uptake rate-associated concentrations (Kt') of attached cells, however, were considerably greater than those of suspended cells and depended on cell density and on percolation velocity. A mathematical model was developed to explain the observed differences in terms of substrate transport to the cells. This model was based on the assumptions that the intrinsic half-maximum uptake rate-associated concentration (Kt) was unchanged and that deviations of Kt' from Kt resulted from the stereometry and the hydrodynamics around the cells. Our calculations showed that (i) diffusion to suspended cells and to single attached cells is efficient and therefore only slightly affects Kt'; (ii) diffusion to cells located on crowded surfaces is considerably lower than that to single attached cells and greatly increases Kt', which depends on the cell density; (iii) the convective-diffusive transport to attached cells that occurs in a percolated column is influenced by the liquid flow and results in dependency of Kt' on the flow rate; and (iv) higher specific affinity of cells correlates with higher susceptibility to diffusion limitation. Properties of the experimental system which limited quantitative proof of exclusively transport-controlled variations of Kt' are discussed.
Comparative studies of genes encoding thermostable L-2-halo acid dehalogenase from Pseudomonas sp. strain YL, other dehalogenases, and two related hypothetical proteins from Escherichia coli
Authors: Nardi-Dei V , Kurihara T , Okamura T , Liu J Q , Koshikawa H , Ozaki H , Terashima Y , Esaki N , Soda K
Published: January 2020

We have determined the nucleotide sequence of the gene encoding thermostable L-2-halo acid dehalogenase (L-DEX) from the 2-chloroacrylate-utilizable bacterium Pseudomonas sp. strain YL. The open reading frame consists of 696 nucleotides corresponding to 232 amino acid residues. The protein molecular weight was estimated to be 26,179, which was in good agreement with the subunit molecular weight of the enzyme. The gene was efficiently expressed in the recombinant Escherichia coli cells: the amount of L-DEX corresponds to about 49% of the total soluble proteins. The predicted amino acid sequence showed a high level of similarity to those of L-DEXs from other bacterial strains and haloacetate dehalogenase H-2 from Moraxella sp. strain B (38 to 57% identity) but a very low level of similarity to those of haloacetate dehalogenase H-1 from Moraxella sp. strain B (10%) and haloalkane dehalogenase from Xanthobacter autotrophicus GJ10 (12%). By searching the protein amino acid sequence database, we found two E. coli hypothetical proteins similar to the Pseudomonas sp. strain YL L-DEX (21 to 22%).
Impact of Antibiotic-Resistant Bacteria on Immune Activation and Clostridioides difficile Infection in the Mouse Intestine
Authors: Keith James W. , Dong Qiwen , Sorbara Matthew T. , Becattini Simone , Sia Jonathan K. , Gjonbalaj Mergim , Seok Ruth , Leiner Ingrid M. , Littmann Eric R. , Pamer Eric G.
Published: January 2020

Antibiotic treatment of patients undergoing complex medical treatments can deplete commensal bacterial strains from the intestinal microbiota, thereby reducing colonization resistance against a wide range of antibiotic-resistant pathogens. Loss of colonization resistance can lead to marked expansion of vancomycin-resistant
Enterococcus faecium
(VRE),
Klebsiella pneumoniae
, and
Escherichia coli
in the intestinal lumen, predisposing patients to bloodstream invasion and sepsis.
Ultrastructure of Hamster Kidney Cell Culture Infected with Herpesvirus
Authors: Hamdy Farouk , Holt Stanley C. , Sevoian Martin
Published: January 2020

Hamster kidney cell culture was found susceptible to infection and replication of herpesvirus of turkey (HVT) as evidenced by cytopathic effect, induction of HVT-specific, complement-fixing antigen, and demonstration of virus particles by electron microscopy. Viral structures at different developmental stages were observed. Several infected cells showed a lamellar inclusion body possibly continuous with the endoplasmic reticulum. The function of these lamellar bodies is not known.
Dithiothreitol-Dependent Antilisterial Activity of Lysates from Normal Macrophages Exposed In Vitro to Culture Fluids from Spleen Cells of BCG-Immunized Mice
Authors: Muirhead Donna Y. , Mallmann Virginia H.
Published: January 2020

The effect of culture fluids from mouse lymphocytes on the antilisterial activity of normal macrophages in vitro was determined. Titers of lysates of macrophages incubated with or without culture fluids from lymphocytes from control mice had titers of 10 to 270 with or without a reducing agent, dithiothreitol. Lysates of macrophages after incubation with culture fluids of spleen lymphocytes from BCG-immunized mice had antilisterial titers with and without dithiothreitol of 197,000 and 810, respectively. This may indicate a dithiothreitol-dependent antilisterial system inherent in activated macrophages of cell-mediated immunity. Lysates of incubated spleen cells and their culture fluids also had slight antilisterial activity.
Neutralizing Activity in Isolated Serum Antibody Fractions from Visna-Infected Sheep
Authors: Mehta P. D. , Thormar H.
Published: January 2020

The neutralization technique was used to detect specific antibodies against visna virus in isolated immunoglobulin (Ig) G
1
, IgG
2
, and IgM fractions of visna-infected sheep serum. The neutralizing antibodies were present chiefly in the IgG
1
class. Low amount of activity was demonstrated in the IgM class, but no significant activity was seen in the IgG
2
class.
Comparison of Antibodies Against Different Viruses in Cerebrospinal Fluid and Serum Samples from Patients with Multiple Sclerosis
Authors: Norrby Erling , Link Hans , Olsson Jan-Edvin , Panelius Martin , Salmi Aimo , Vandvik Bodvar
Published: January 2020

The occurrence of a local production in the central nervous system (CNS) of antibodies against different selected viruses was analyzed by comparison of titers in serum and cerebrospinal fluid samples from groups of 50 patients with multiple sclerosis from Finland, Norway, and Sweden. Measles antibodies were determined in hemagglutination inhibition, hemolysis inhibition, and nucleocapsid complement fixation tests; mumps, parainfluenza virus type 1, and rubella virus antibodies were determined in hemagglutination inhibition tests; and herpes simplex virus type 1 antibodies were determined in passive hemagglutination tests. For reference purposes tests were also made for adenovirus antibodies in penton hemagglutination enhancement tests and poliovirus antibodies in neutralization enhancement tests. Among the 150 multiple sclerosis patients, a local production of antibodies against measles virus was found in the CNS in 57%, against rubella virus in 19%, mumps virus in 15%, herpes simplex virus type 1 in 11%, and parainfluenza virus type 1 (Sendai) in 3%. A local production in the CNS of antibodies against any of the viruses studied was found in 71% of multiple sclerosis patients. These included 48, 16, and 7% that produced antibodies to one, two, and three or more viruses, respectively.
Immunity to
Escherichia coli
in Pigs: Adhesion of Enteropathogenic
Escherichia coli
to Isolated Intestinal Epithelial Cells
Authors: Wilson M. R. , Hohmann A. W.
Published: January 2020

A method was developed to test for the ability of
Escherichia coli
to adhere to isolated intestinal epithelial cells. Of the
E. coli
tested, those having either K88ac or K88ab antigens adhered to the cells, and those which did not have these antigens did not. Since some enteropathogenic
E. coli
did not have the ability to adhere, it is assumed that adherence is not an essential factor of pathogenesis but rather should be considered an enhancement to the pathogenicity of some
E. coli
. None of the
E. coli
enteropathogens of cattle tested adhered to either pig or cattle cells. Similarly, human strains did not adhere to pig cells. Although the test system may not have been ideal for human or bovine
E. coli
, the results reported here suggest that adhesiveness is a property limited to porcine enteropathogenic
E. coli
carrying one of the K88 antigens. Adhesiveness is associated with the K88c or K88b antigens, and their adhesive ability is only neutralizable by the homologous antisera.
Plaque Size Reduction as a Measure of Viral Cell-Mediated Immunity
Authors: Simmons Richard L. , Centifanto Ysolina , Kaufman Herbert E.
Published: January 2020

This new assay of viral cell-mediated immunity is sensitive, reproducible, and in many ways resembles the in vivo state. The spread of herpes simplex virus between adjacent monolayer cells was inhibited in the presence of spleen cells from guinea pigs sensitized to that virus. This in vitro control of viral growth was quantified by determining plaque size in monolayers to which were added sensitized spleen cells as opposed to nonsensitized or no spleen cells. The simple measurement of plaque size reduction as an in vitro test of viral cell-mediated immunity is described. In addition to correlating highly with skin testing and macrophage migration inhibition as a test of viral cell-mediated immunity, the ability of sensitized spleen cells to reduce plaque size developed by day 7, paralleling the onset of delayed cutaneous hypersensitivity. The specificity of this lymphocyte-mediated interaction was demonstrated by the inability of herpes simplex virus-sensitized spleen cells to alter the growth of vaccinia virus in cell culture. A ratio of sensitized spleen cells to monolayer cells of 6:1 resulted in significant plaque size reduction on both HEp-2 and conjunctiva monolayers. The data presented demonstrate the potential usefulness of plaque size reduction as a technically simple, specific, and more direct measure of cellular antiviral activity.
Purification of
Treponema pallidum
from Infected Rabbit Tissue: Resolution into Two Treponemal Populations
Authors: Baseman Joel B. , Nichols Jean C. , Rumpp J. William , Hayes Nancy S.
Published: January 2020

Virulent
Treponema pallidum
organisms, extracted from infected rabbit testes, were subjected to velocity sedimentation in discontinuous gradients of Hypaque, a high density, low viscosity material. After centrifugation of extracts at 20 C for 45 min at 100,000 x
g
, treponemes separated into two distinct bands based upon their relative velocities, although some variation was observed in the densities of the two bands and the number of treponemes per band. Rabbit tissue components sedimented more rapidly. Dark field and electron microscopy of preparations after velocity sedimentation indicated that treponemes retained general structural characteristics and no tissue contamination occurred in the treponemal fractions. Purification of treponemes in Hypaque resulted in their loss of motility and infectivity based upon animal inoculation. Antigenicity with respect to reactivity with antibody was preserved as shown by the high fluorescence intensity of treponemes in the fluorescent treponemal antibody adsorption test.
Cytotoxicity of
Mycoplasma pneumoniae
Membranes
Authors: Gabridge Michael G. , Johnson Cynthia K. , Cameron Alexander M.
Published: January 2020

Organ cultures of adult hamster trachea were used to evaluate the cytotoxic potential of cell fractions of
Mycoplasma pneumoniae
. Cytoplasm was essentially devoid of activity, whereas viable cells and membrane preparations, at a level of 25 μg of protein per ml, induced necrosis. Damage, as revealed by light and electron microscopy, included ciliostasis, vacuolization, loss of ciliated respiratory epithelial cells, disorganization, and a loss of polarity. Dose response data indicated that the speed and degree of cytotoxicity was directly related to the concentration of membranes. Doses of 30 to 60 μg of protein per ml could reduce relative ciliary activity to 20% of the control level within 4 days. Membranes prepared after freeze-thaw lysis of cells were almost twice as active as those isolated after a combination of osmotic and sonic shock. Membranes of
M. fermentans
were inactive, though both the FH and M129 strains of
M. pneumoniae
were toxic. These data indicate that the toxic factor responsible for
M. pneumoniae
may be located in the cell membrane.
Test for enterotoxigenic Escherichia coli using Y-1 adrenal cells in miniculture
Authors: Sack D A , Sack R B
Published: January 2020

A rapid, potentially clinically useful test for detection of enterotoxigenic Escherichia coli is described. Whole bacterial cultures of enterotoxigenic E. coli, when briefly exposed to Y1 adrenal cells in tissue miniculture, effect a rounding response in the tissue culture that can be discerned at 18 to 24 h. The tissue culture technique agreed with the rabbit ileal loop in all 58 enterotoxigenic and 52 non-enterotoxigenic E. coli strains tested.
Interaction of cultured mammalian cells with [125I] diphtheria toxin
Authors: Bonventre P F , Saelinger C B , Ivins B , Woscinski C , Amorini M
Published: January 2020

The characteristics of cell adsorption and pinocytotic uptake of diphtheria toxin by several mammalian cell types were studied. Purified toxin iodinated by a solid-state lactoperoxidase method provided preparations of high specific activity and unaltered biological activity. Dephtheria toxin-sensitive HEp-2 cells and guinea pig macrophage cultures were compared with resistant mouse L-929 cells. At 37 C the resistant cells in monolayer adsorbed and internalized [125I] toxin to a greater extent than did the HEp-2 cell cultures; no significant differences were observed at 5 C. Ammonium chloride protection levels did not alter uptake of toxin by either L-929 OR HEp-2 cells. Biological activity of the iodinated toxin, however, was negated provided the presence of ammonium chloride was maintained. The ammonium salt appears to maintain toxin in a state amenable to antitoxin neutralization. Guinea pig macrophages internalized iodinated toxin to a level 10 times greater than the established cell lines. In spite of the increased uptake of toxin by the endocytic cells, ammonium chloride prevented expression of toxicity. In an artificial system, toxin adsorbed to polystyrene latex spheres and internalized by guinea pig macrophages during phagocytosis did express biological activity. Ammonium chloride afforded some but not total protection against toxin present in the phagocytic vacuoles. The data suggest that two mechanisms of toxin uptake by susceptible cells may be operative. Toxin taken into the cell by a pinocytotic process probably is not ordinarily of physiological significance since it is usually degraded by lysosomal enzymes before it can reach cytoplasmic constituents on which it acts. When large quantities of toxin are pinocytized, toxicity may be expressed before enzymatic degradation is complete. A more specific uptake involving direct passage of the toxin through the plasma membrane may be the mechanism leading to cell death in the majority of instances.
Virologic and serologic studies of zoo birds for Marek's disease virus infection
Authors: Cho B R , Kenzy S G
Published: January 2020

One hundred and eleven zoo birds representing 49 species in 14 orders were examined for Marek's disease (MD) herpesvirus (MDHV) infection. MDHV was isolated from 10 birds, all belonging to genus Gallus. The precipitating antibodies against MDHV were demonstrated only in the Gallus birds, when 51 selected birds including 34 Galliformes and 17 other birds representing 12 species from nine orders were examined. The 10 MDHV isolates all induced morphologically similar plaques in cell cultures closely resembling those of HN strain, a low pathogenic isolate of MDHV. Six of the 10 isolates, when inoculated into an experimental line of chickens highly susceptible to MD, caused only a minimal degree of histologic lesions without causing clinical MD, gross MD lesions, or deaths from MD. Natural hosts of MD are probably Galliformes, primarily affecting Gallus and less often other genera of Galliformes.
Lanthanum inhibition of Vibrio cholerae and Escherichia coli enterotoxin-induced enterosorption and its effects on intestinal mucosa cyclic adenosine 3',5'-monophosphate and cyclic guanosine 3',5'-monophosphate levels
Authors: Leitch G J , Amer M S
Published: January 2020

Several trivalent cations, including lanthanum (La3+), inhibited the secretion (enterosorption) induced by the enterotoxins of Vibrio cholerae and Escherichia coli in the rabbit ileum in vivo. High concentrations (greater than 10 mM) of La3+ were required to inhibit cholera enterotoxin (CE)-induced enterosorption, probably because of the adsorption of the La3+ often potentiated the CE-induced enterosorption. If luminal La3+ exposure followed CE exposure, some recovery of the enterosorptive response was observed. The longer the lag between the CE exposure and the La3+ exposure, the greater was the recovery of the enterosorptive response. Lanthanum inhibited HCO3- secretion more than Cl- secretion. By altering the luminal fluid pH at the time of La3+ exposure, it was found that La3+ was adsorbed to negatively charged luminal sites, having an apparent pK between 2.5 and 3.0. Although La3+ antagonized the enterosorptive response to CE, it mimicked rather than antagonized the cyclic adenosine 3',5'-monophosphate elevation and cyclic guanosine 3',5'-monophosphate depression induced by the toxin. It is therefore concluded that the La3+ inhibition of the CE-induced enterosorption must have occurred at a site following the generation of the cyclic nucleotides. Cholera enterotoxin caused complex time-dependent changes in the mucosal cyclic adenosine 3',5'-monophosphate and cyclic guanosine 3',5'-monophosphate levels, as revealed by studying tissue cyclic adenosine 3',5'-monophosphate/cyclic guanosine 3',5'-monophosphate ratios. The possible roles these two cyclic nucleotides may play in the pathogenesis of the cholera diarrhea are discussed.
Paramyxovirus-avian cell relationship: discrepant impact of 6-azauridine on virus production by susceptible and less susceptible cells
Authors: Saint Geme J W , Martin H L , Davis C W
Published: January 2020

The replication of mumps virus in susceptible chicken embryonic heart cells was escalated by daily treatment of cultures with 6-azauridine (6-AU). On the other hand, virus production by less susceptible liver cells was depressed by 6-AU. The population of infected susceptible cells was not increased, but the release of virus by infected susceptible cells was enhanced 20-fold by 10 mug of 6-AU per ml. Less susceptible cells, which incorporated less ribonucleic acid and protein precursor than susceptible cells, sustained a constant level of viral release during 6-AU treatment; however, the number of infected less susceptible cells underwent substantial decline.
Immunoglobulin E antibody formation in response to homologous rabbit albumin heavily substituted with dinitrophenol: effect of adjuvant
Authors: Brummer E
Published: January 2020

Although much progess has been made in the detection and characterization of homocytotropic antibodies, identification of the factors which control their synthesis remains to be determined. To assess the influence of different adjuvants on anti-dinitrophenol (DNP) immunoglobulin E (IgE) antibody responses, rabbits were immunized with adjuvant plus homologous albumin (HRA) heavily substituted with DNP (DNP30-HRA). This antigen in rabbits has a B cell-reactive determinant (DNP) and weak non-B cell-reactive determinants (new antigenic determinants) which sensitize rabbits for delayed-type hypersensitivity reactions to DNP30-HRA. It was postulated that the anti-DNP IgE response to DNP30-HRA could be regulated if the immunogenicity of the weak non-B cell-reactive determinants (new antigenic determinants) in DNP30-HRA could be manipulated by adjuvants and dosage. Complete Freund adjuvant and incomplete Freund adjuvant increased the immunogenicity of the new antigenic determinants in DNP30-HRA (10 mg) much more than did alum. However, equivalent primary anti-DNP IgE responses were made by all rabbits sensitized with this dose, regardless of the adjuvant used. Larger doses of DNP30-HRA (25 mg) in alum sensitized rabbits for strong delayed-type hypersensitivity reactions to DNP30-HRA and also elicited enhanced and persistent primary anti-DNP IgE responses. Enhanced but transient primary anti-DNP IgE responses were elicited by 25 mg of DNP30-HRA in incomplete Freund adjuvant. In contrast, no primary anti-DNP IgE responses were made to 25 mg of DNP30-HRA in complete Freund adjuvant. Regardless of the adjuvant or dosage used for primary immunization, no secondary anti-DNP IgE responses to DNP30-HRA were detected.
Detection of virus-specific antibody-forming cells of mice immunized with Newcastle disease virus
Authors: Kim Y T , Ault J , Wodzinski R J
Published: January 2020

The hemolytic plaque assay was adapted to the detection of antibodies to Newcastle disease virus (NDV) in an in vivo, an in vitro system, and a combined in vivo-in vitro system. Several conditions were tested for coupling of sheep erythrocytes to NDV and for the kinetics of plaque formation in the in vivo and in vitro systems. The one set of conditions which provided the best responses is presented. The effect of multiple injections of NDV into mice on plaque formation was optimized.
Factors in the inactivation of Encephalomyocarditis virus in aerosols
Authors: de Jong J C , Harmsen M , Trouwborst T
Published: January 2020

Encephalomyocarditis virus in aerosols is inactivated rapidly at relative humidities below 50%. In glycerol-water mixtures a similar decrease of infectivity occurs when the glycerol concentration exceeds 78% (wt/wt), corresponding to a relative humidity of 50%. The decay in aerosols does not involve oxygen or surface-dependent factors. Variation of temperature shows the inactivation to be a low-energy process with an activation enthalpy of 15 kcal per mol. The damage could be ascribed to dehydration of the virion, presumably proceeding to removal of structurally essential water molecules. This might trigger irreversible changes in the protein coat, resulting in disintegration of the virion.
Prevention of Streptococcus mutans infection of tooth surfaces by salivary antibody in Irus monkeys (Macaca fascicularis)
Authors: Evans R T , Emmings F G , Genco R J
Published: January 2020

Four irus monkeys (Macaca fascicularis) were immunized with Streptococcus mutans 6715 killed cells and cell products by injection in the vicinity of the major salivary glands and by instillation into the parotid glands via the ducts. After immune group and a sham-immunized control group of monkeys were infected orally with viable strain 6715 organisms. Dental plaque samples were taken at intervals from the buccal and lingual grooves of the first permanent molars. These samples were evaluated for recovery of strain 6715 by cultural methods. In addition, individual samples were taken from 10 representative tooth surfaces and were evaluated by indirect immunofluorescent staining for strain 6715. Results showed that immune monkeys had fewer infected surfaces and fewer organisms on the infected surfaces than the control animals. These studies indicate that salivary antibody to cariogenic streptococci inhibits implantation of these organisms in dental plaque and may be protective against dental caries.
Agglutinating serum for distinguishing Staphylococcus aureus of human biotype
Authors: Live I
Published: January 2020

Antiserum to Staphylococcus aureus strain 17 was treated with S. aureus strain 61218 until the antibodies against thermostable agglutinogen were removed. The absorbed serum agglutinated phage-typable as well as phageuntypable staphylococci of human biotype, whether recovered from people or from dogs.
Immunogenic Mycobacterial Ribosomal and Ribonucleic Acid Preparations: Chemical and Physical Characteristics
Authors: Youmans Anne S. , Youmans Guy P.
Published: January 2020

Five to 20% linear sucrose gradients were used to obtain sedimentation patterns of mycobacterial ribosomes, ribosomal subfractions, and ribonucleic acid (RNA) preparations. Classical 70
S
ribosomes were obtained when 10
−1
m
magnesium chloride was used. These, when dialyzed against 10
−4
m
MgCl
2
, yielded typical 50
S
, 30
S
, and smaller ribosomal subunits. The 30
S
subunits were the most immunogenic under these conditions. A ribosomal preparation containing subunits which varied from 2.5 to 40
S
was fractionated by collecting five fractions from a sucrose gradient; based upon the amount of nucleic acid present, the fraction containing the 40
S
particles was most immunogenic. Physical and chemical evidence suggested that mycobacterial RNA preparations extracted with 65% ethyl alcohol from the ribosomes and diluted in distilled water, were either double-stranded, or mostly double-helical, or had a highly organized secondary structure. This was based on the following observations. (i) Native RNA was resistant to trace amounts of ribonuclease. (ii) The approximate T
m
value in SSC buffer (0.15
m
NaCl plus 0.015
m
sodium citrate) was greater than 85 C and in 0.1 SSC buffer was 55 C; the RNA diluted in SSC buffer produced a hypochromic effect on cooling at room temperature. (iii) Formaldehyde, in the presence of SSC buffer, decreased the T
m
of the RNA to approximately 55 C, and there was no hypochromic effect on cooling. (iv) Formaldehyde did not increase the wavelength of maximal adsorption of the RNA. (v) The purine/pyrimidine ratio was close to one. (vi) The major peak of the RNA sedimented in the more dense zones of the sucrose gradients. There was a relationship between the sedimentation pattern obtained with the RNA-protein subunits on sucrose gradients and immunogenicity; several examples are given. RNA-protein complexes of approximately 14 to 20
S
, and occasionally 23
S
in the major peak, appeared to produce the highest immune response. Smaller RNA-protein complexes such as 6
S
, which were obtained when the RNA preparation was diluted in certain buffers, were much less immunogenic. This was confirmed by collecting five fractions from sucrose gradients and finding the third fraction (containing RNA-protein complexes approximately 15 to 16
S
) the most immunogenic. Immunogenic activity was apparently related to the structure of the RNA since it was maximal when the RNA appeared to be either double stranded, double helical, or had a highly organized structure.
Crossed immunoelectrophoretic analysis of two antigen extracts of Thermoactinomyces candidus
Authors: Hollick G E , Larsh H W
Published: January 2020

A pyridine extract antigen and a double-dialysis antigen (DDA) obtained from Thermoactinomyces candidus were analyzed by crossed immunoelectrophoresis. In addition, the heat lability, pronase sensitivity, and isolectric points of the components of the DDA were determined. By using antisera raised against crude pyridine extract antigen, two immunogenic components were resolved by crossed immunoelectrophoresis. A similar analysis of DDA using antisera raised against crude DDA revealed 15 immunogens. All but six components were heat labile, whereas pronase had little effect on the number of resolvable components. Intermediate gel crossed immunoelectrophoresis using antiserum raised to whole spores detected six immunogenic components, four of which were also detected by the anti-DDA serum. A total of 19 bands were obtained when the DDA was subjected to flatbed isoelectric focusing on polyacrylamide gels. The isoelectric points for the various components were found to range from 3.5 to 5.7. Crossed immunoelectrophoresis using isoelectric focusing in the first dimension yielded at least 16 immunogenic components. Six components with isoelectric points falling in the range of 4.5 to 6.4 were found to be resistant to heat. A comparison with antigens obtained from other thermophilic actinomycetes is presented.
Prevalence of Pilus Antigens, Enterotoxin Types, and Enteropathogenicity Among K88-Negative Enterotoxigenic
Escherichia coli
from Neonatal Pigs
Authors: Moon H. W. , Kohler E. M. , Schneider R. A. , Whipp S. C.
Published: January 2020

Enterotoxigenic
Escherichia coli
(ETEC) that were isolated from neonatal pigs and that did not react in preliminary tests for pilus antigen K88 were subjected to additional tests for K88 and for pilus antigens K99 and 987P. Four such isolates produced K88, 9 isolates produced K99, 55 isolates produced 987P, and the remaining 43 isolates produced none of the three pilus antigens (3P
−
). Immunofluorescence tests of ileal sections from pigs were more sensitive for 987P detection than was serum agglutination of bacteria grown from the ileum. Most ETEC that produced K88, K99, or 987P were enteropathogenic (adhered to ileal villi, colonized intensively, and caused profuse diarrhea) when given to neonatal pigs. In contrast, only 3 of the 43 ETEC that produced none of the pilus antigens were enteropathogenic. The isolates were also tested for the type of enterotoxin produced. The K88
+
isolates all produced heat-labile enterotoxin (LT) detectable in cultured adrenal cells (i.e., were LT
+
). None of the 987P
+
, K99
+
, or enterpathogenic 3P
−
isolates produced LT. However (except for a single K99
+
isolate), they all produced heat-stable enterotoxin detectable in infant mice (STa
+
). Sixteen isolates produced neither LT nor STa but did produce enterotoxin detectable in ligated intestinal loops of pigs (STb). Most of these LT
−
STa
−
STb
+
isolates were also K88
−
, K99
−
, and 987P
−
and non-enteropathogenic. One of them was K99
+
and enteropathogenic. Our conclusions are as follows. (i) Most enteropathogenic ETEC from neonatal pigs produce either K88, 987P, or K99; however, there are some that produce none of the three antigens. (ii) Immunofluorescence tests for pilus antigens produced in vivo are recommended for the diagnosis of ETEC infections. (iii) Reports of LT
−
STa
−
STb
+
swine ETEC are confirmed; furthermore, such isolates can be enteropathogenic.
Host Defenses in Murine Malaria: Immunological Characteristics of a Protracted State of Immunity to
Plasmodium yoelii
Authors: Murphy James R.
Published: January 2020

Random-bred ICR mice recovered from infection with avirulent
Plasmodium yoelii
were challenged at various later times with virulent
P. yoelii
or with another species of
Plasmodium, P. berghei
, to characterize the immunological nature of the long-term state of immunity generated in response to the avirulent infection. It was found that recovered mice resisted lethal challenge with virulent
P. yoelii
through at least 416 days after primary infection. However, the quality of this immunity changed as the time after avirulent infection increased. Mice challenged early after recovery were able to prevent the development of patent parasitemia. Later, these immune animals lost this capacity and after challenge infections progressed to patency at the same rate as did nonimmune controls. However, after the establishment of parasitemia, those animals which had encountered the homologous parasite a long time before controlled, and then eliminated, blood infection and survived. The “early” state of immunity was expressed by animals which may have harbored small numbers of viable avirulent parasites and possessed a protective humoral factor which could passively transfer anti-
P. yoelii
activity to naive recipients. In contrast, animals with “late” immunity showed evidence of neither persisting avirulent parasites nor serum anti-
P. yoelii
activity. The results support the proposition that immunity to this parasite exists as two distinct but interrelated states of immunological reactivity: an early “active” immunity and a later state which has characteristics suggestive of a state of immunological memory wherewith the animals were capable of anamnestically responding to
P. yoelii
challenge. Little evidence of heterologous immunity to
P. berghei
was observed for animals recovered from
P. yoelii
.
Clearance of
Serratia marcescens
from Lungs of Normal Mice
Authors: Southern Paul M. , Pierce Alan K. , Sanford Jay P.
Published: January 2020

After aerosol deposition of
Serratia marcescens
in mice, initial delayed pulmonary clearance was followed between 4 and 24 hr later by progressive elimination.
Experimental
Pseudomonas aeruginosa
Infection of the Mouse Cornea
Authors: Gerke John R. , Magliocco Michael V.
Published: January 2020

Pseudomonas aeruginosa
infection of human cornea is rare but serious. The work of previous investigators using experimental infection primarily of rabbit cornea resulted in successful therapy for 10 to 50% of clinical cases. The advantage of using the mouse is demonstrated. The methods we adapted for characterizing the untreated experimental infection included: incising the cornea to enable establishing the infection; corneal examination with a steroscopic microscope; grading corneal pathology; qualitative and quantitative monitoring of the infecting bacteria by culturing and staining sectioned and dissected tissues. The characteristics of the tissue pathology, host response, and infection were similar to those reported for other animals and man. Corneal pathology was frequently nearly maximal 1 day after infection; host response involved a progression of events of long duration; pathology persisted well beyond the period of bacterial infection. The infection was essentially noncommunicable, and invasiveness was limited to the tissues of the incised eye. The results show the possibility of tests for invasiveness of clinical isolates and for screening for therapeutic and prophylactic measures.
Macrophage Cytophilic Antibody in Mice: Effect of Bacterial Lipopolysaccharide on the Uptake of Immunoglobulins by Mouse Peritoneal Cells
Authors: Tizard Ian R.
Published: January 2020

Injection of lipopolysaccharide from
Escherichia coli
intravenously into mice affected the ability of their peritoneal macrophages to adsorb antisheep erythrocyte cytophilic antibodies in vitro. After a single intravenous injection of lipopolysaccharide, the alteration in antibody uptake took the form of a triphasic response. An early evanescent increase in adsorptive capacity took place, which reached a maximum 5 min after injection and was followed immediately by a phase of depressed uptake of antibody. Enhancement of antibody uptake then increased to reach a maximum about 24 hr after injection, before declining slowly. The second enhancement phase was inhibited by prior immunization with
E. coli
or after multiple injections of lipopolysaccharide. Exposure of macrophages to lipopolysaccharide in vitro did not alter their capacity to take up cytophilic antibody. Changes in the capacity of macrophages and polymorphonuclear neutrophil leukocytes to adsorb opsonized erythrocytes were induced by injection of lipopolysaccharide and were similar to those induced with respect to the uptake of cytophilic antibodies by macrophages.
Latent Syphilis: Immunoglobulins Reactive in Immunofluorescence and Other Serological Tests
Authors: Julian A. J. , Logan L. C. , Norins L. C. , Scotti A. T.
Published: January 2020

Study of sera from 69 patients with untreated or inadequately treated latent syphilis revealed that immunoglobulin (Ig)G antibodies made up the bulk of the fluorescent treponemal antibody-absorption (FTA-ABS)-test reactivity found in the sera. IgM and IgA antibodies also contributed in some cases. Venereal Disease Research Laboratory slide-test reactivity was found in both 19 and 7
S
serum fractions, whereas
Treponema pallidum
immobilization-test reactivity was found mainly in the 7
S
fraction.
Effect of β-3-Thienylalanine on Antibody Synthesis IV. Suppression of the Immune Response in Mice
Authors: Misefari Aldo , La Via Mariano F.
Published: January 2020

The analogue of phenylalanine, β-3-thienylalanine (β-3-TA), inhibits the primary and secondary immune responses to sheep red blood cells in CBA mice fed with phenylalanine-free diet. The optimal dose of β-3-TA needed to obtain maximum immunosuppression with minimal toxicity is 250 mg per kg per day. The drug is maximally effective when administered for 7 days, beginning 2 days prior to primary immunization. With these experimental conditions, the antibody titers and the numbers of direct and indirect plaque-forming cells are greatly reduced during the primary and the secondary immune response.
Bactericidal activity of human lactoferrin: influence of physical conditions and metabolic state of the target microorganism
Authors: Arnold R R , Russell J E , Champion W J , Gauthier J J
Published: January 2020

Lactoferrin is an iron-binding protein that is bactericidal against Streptococcus mutans and several other microorganisms. In this study, the influence of several physical conditions as well as the metabolic state of S. mutans on lactoferrin susceptibility were investigated. After exposure to lactoferrin, a 15-min lag period occurred before the initiation of killing, indicating that a two-step process is involved in lactoferrin killing. Cultures harvested during the early exponential phase were very sensitive to lactoferrin, whereas cultures harvested in the early stationary phase were markedly more resistant. The rate of killing was dependent on temperature; there was no loss of viability at 2 degrees C. Killing occurred at pH 5.0 to 6.0 in water and 20 mM glycine, but did not occur at any pH in 50 mM sodium phosphate or N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES) buffer. Addition of exogenous ferrous or ferric ions did not reverse or prevent lactoferrin killing, nor did addition of 1 mM magnesium chloride.