bluuebunny/crossref_metadata_2025 huggingface dataset:
Lipids of Putative Relevance to Virulence in
Mycobacterium tuberculosis
: Correlation of Virulence with Elaboration of Sulfatides and Strongly Acidic Lipids
Authors: Goren Mayer B. , Brokl Olga , Schaefer Werner B.
Published: January 2020

From examination of some 40 patient strains of
Mycobacterium tuberculosis
, a statistically very significant correlation (Spearman's rho) can be drawn between the root index of virulence for the guinea pig (D. A. Mitchison) and the ability of the individual strains to elaborate strongly acidic lipids (SAL) in culture. These include both sulfatides (SL) and phospholipids (PL). Since essentially all, if indeed not all, of the virulent and only few attenuated strains are prolific in elaborating SAL, this criterion may be a necessary requirement for the expression of virulence in
M. tuberculosis.
Tested by chi-square, this premise is seen to be statistically and pragmatically highly significant. We speculate that SL may contribute to the pathogenesis of tuberculosis because of a demonstrable activity directed against host liver mitochondrial membranes (manuscript in preparation) and its synergistic potentiation of the specific toxicity of trehalose dimycolate (cord factor). The activity may also be expressed against phagosomal and lysosomal membranes within macrophages. Because of their strongly anionic character, SL and PL may interact with cationic sites on lysosomal hydrolases with resultant immobilization and/or inactivation of the enzymes. By a similar mechanism, these ionic lipids may alter the activity of bactericidal basic proteins, previously recognized in the lysosomal armamentarium. Since a minor but significant fraction of demonstrably attenuated strains is nevertheless prolific in SL or SAL elaboration, this facility alone is evidently not a sufficient criterion for expression of virulence.
Streptolysin O Inhibition of Neutrophil Chemotaxis and Mobility: Nonimmune Phenomenon with Species Specificity
Authors: Van Epps Dennis E. , Andersen Burton R.
Published: January 2020

The effects of streptolysin O (SO) (1 to 4 hemolytic units) on the mobility of neutrophilic leukocytes from humans, baboons, sheep, and rabbits were compared. After SO treatment, chemotaxis and random mobility of human neutrophils were markedly suppressed, baboon and sheep neutrophils were partially suppressed, and rabbit neutrophils were unaffected and demonstrated normal chemotaxis and mobility. The amounts of SO used in the mobility studies caused no leukocyte lysis or trypan blue uptake by human, baboon, or sheep cells, and minimal lysis or trypan blue uptake by rabbit cells. The possible involvement of immune mediators in the observed inhibition of human neutrophils was considered and excluded by the following studies. White blood cells from humans with humoral or cellular immune deficiencies responded in a manner similar to normal human cells; supernatant solutions from SO-treated human white blood cells did not contain a chemotactic suppressor; preincubation of SO with cholesterol (an inhibitor of SO hemolytic activity) caused loss of the chemotactic suppressive effect of the toxin on human leukocytes; and leukocytes from rabbits preimmunized with SO remained refractory to chemotactic suppression.
Oxidative Peptide Cleavage and Decarboxylation by the MPO-H
2
O
2
-Cl
−
Antimicrobial System
Authors: Selvaraj Ratnam J. , Paul Benoy B. , Strauss Robert R. , Jacobs A. Alice , Sbarra Anthony J.
Published: January 2020

The antimicrobial activities of the myeloperoxidase-H
2
O
2
-halide system have received considerable attention recently. The precise mechanism by which this system exerts its lethal activity is presently not clear. In an effort to learn more regarding a possible mechanism of action, the susceptibility of protein-bound amino acids to enzymatic attack by myeloperoxidase (MPO) in the presence of chloride ions was investigated. [1, 7-
14
C]diaminopimelic acid (DAP) was incorporated into
Escherichia coli
W-7 proteins with little randomization of the radioactivity. Under appropriate conditions, it was observed that the MPO-H
2
O
2
-halide system released approximately 94% of the radioactivity from labeled bacteria. This would indicate that, in addition to decarboxylation, peptide bonds are also split during this reaction. The oxidative decarboxylation of DAP-labeled bacteria by MPO (i) is Cl
−
dependent, (ii) has an acid pH optimum, (iii) requires a specific concentration of H
2
O
2
for activity, (iv) reaches a plateau by 25 min, and (v) is markedly inhibited by taurine. These properties are similar to those observed with free amino acids. It appears from these data that MPO can not only decarboxylate free and bound amino acids, yielding aldehydes, but also it can actively participate in oxidative peptide cleavage. Both of those activities may play a critical role in the microbicidal action of the leukocyte.
Neuraminidase Activity in
Streptococcus sanguis
and in the Viridans Group, and Occurrence of Acylneuraminate Lyase in Viridans Organisms Isolated from Patients with Septicemia
Authors: Müller H. E.
Published: January 2020

The enzyme neuraminidase (EC 3.2.1.18) was found to be strongly active in different types of
Streptococcus sanguis
and
S. viridans
, and, in addition, the occurrence of the enzyme acylneuraminate pyruvate lyase (EC 4.1.3.3) was described in
S. viridans
. The enzyme-active bacteria strains were isolated from blood cultures of patients with septicemia. Whereas
S. sanguis
lost its strong neuraminidase activity after some weeks,
S. viridans
retained its enzyme activity for a long time in culture. Immunoelectrophoretic studies of the blood cultures of patients with streptococcal infections showed the loss of neuraminic acid in most glycoproteins of the serum, proving the in vivo action of neuraminidase. The pathogenic role of neuraminidase is discussed in streptococcal septicemia from the viewpoint of present knowledge.
Biochemical Properties of
Escherichia coli
Low-Molecular-Weight, Heat-Stable Enterotoxin
Authors: Jacks Thomas M. , Wu Bo Jack
Published: January 2020

The low-molecular-weight, heat-stable type of
Escherichia coli
enterotoxin (ST) was obtained from sterile syncase broth filtrates of human and animal enteropathogenic
E. coli
strains. ST was assayed in infant mice, and it was found that this assay was specific for ST in that the high-molecular-weight, heat-labile type of
E. coli
exterotoxin would not cause fluid accumulation in these animals. ST was first detected in the broth of a culture of human strain 334A(015:H11) 5 h after inoculation, immediately after the log phase of growth; the highest concentration of ST occurred at 24 h after inoculation. ST was purified 13-fold by ultrafiltration and gel filtration chromatography. The purest preparation contained 15% protein and 2% carbohydrate. The mean effective dose or 1 unit dose in infant mice was 5.0 μg/mouse. The ST molecular weight was between 1,000 and 10,000, and its activity was resistant to acid, trypsin, and Pronase.
Variation in the In Vitro Migration of Sensitized Guinea Pig Peritoneal Exudate Cells in the Presence of Coccidioidin
Authors: Zabezensky Ferne , Northey William T.
Published: January 2020

Guinea pigs were immunized by intramuscular injection of arthrospores from the M11 strain of
Coccidioides immitis
, and the peritoneal exudate cells were harvested 4 to 6 weeks later. After incubation with various concentrations of coccidioidin in tissue culture, the area of all migration was measured. Results of this study indicate that at a critical level, a variance of 0.1 μg of antigen per ml, determined the difference between approximately 88% migration and 5% migration as compared with control cells incubated in the absence of antigen. The concentration of antigen (ASU-9 stock coccidioidin concentrate) required to produce essentially complete inhibition of migration was determined to be 12.5 μg/ml.
Electron Microscope Study of the Interaction of Vaccinia Virus with Macrophages from Immunized and Nonimmunized Rabbits
Authors: Greer B. , Delfs D. , McElree H.
Published: January 2020

A study using the electron microscope was conducted with the objective of comparing the efficiency of phagocytosis and the subsequent fate of the vaccinia virus in immune and nonimmune rabbit macrophages. Although immune rabbit macrophages inhibited viral replication, they did not differ from permissive nonimmune rabbit macrophages in their ability to ingest the virus. In addition, the immune cells processed the vaccinia virus through the first stage of uncoating as evidenced by the observation of viral cores in the cell cytoplasm. These data support the thesis that the failure of vaccinia replication in immune macrophages is a function of intracellular mechanisms which operate at some point in the replicative sequence after the first stage of uncoating.
Stimulation of Steroidogenesis in Tissue Culture by Enterotoxigenic
Escherichia coli
and Its Neutralization by Specific Antiserum
Authors: Donta Sam T. , Smith Douglas M.
Published: January 2020

Y1 adrenal cells in monolayer tissue culture react to culture filtrates from enterotoxigenic strains of
Escherichia coli
, but not to those from nontoxigenic strains, by undergoing morphological changes similar to those inducible by cholera enterotoxin and increasing their production of steroids. Heating destroys the ability of crude preparations of the
E. coli
enterotoxin to effect these tissue culture changes. None of a number of culture filtrates of other enteric or enteropathogenic bacteria were capable of inducing either the morphological changes or steroidogenesis. The maximal degree of steroidogenesis achievable with
E. coli
enterotoxin was comparable to that of cholera enterotoxin and could not be further increased by combination of the two toxins. As with cholera enterotoxin, removal of the
E. coli
toxin from the tissue culture medium after an initial brief exposure of the cells to the toxin was accompanied by some decrease in maximal steroidogenesis and no changes in either the onset or the permanency of the morphological changes. Antiserum raised to one of the crude
E. coli
enterotoxins was capable of completely neutralizing the steroidogenic effects and preventing the morphological changes secondary to a variety of different enterotoxigenic strains of
E. coli
. At the concentrations tested, this antiserum was not effective in preventing these same tissue culture changes inducible by cholera enterotoxin. The results of these and other related experiments suggest that cholera and heat-labile
E. coli
enterotoxins have similar mechanisms of action which are dissimilar to those of the other enterotoxins thus far described and tested.
Attenuation of Rhinovirus Type 15: Relation of Illness to Plaque Size
Authors: Douglas R. Gordon , Couch Robert B. , Baxter Barbara D. , Gough Michael
Published: January 2020

Rhinovirus type 15 passaged three times in WI-38 cells produced illness in only one of 35 volunteers, but infection resulted in formation of significant quantities of antibodies in the serums of 100%, and in nasal secretions of 89%, of infected volunteers. The inoculum contained large- (60%) and small- (40%) plaque variants. “Purified” large- and small-plaque inocula were prepared, and each was administered to 20 volunteers. There was a significant association of illness with the small-plaque inocula (
P
< 0.01) but the incidence of infection, quantitative virus shedding patterns, and mean serum and nasal secretory antibodies were not significantly different between the two groups. These findings suggest that plaque size may be an in vitro marker of attenuation of illness production by rhinoviruses.
Corticosteroids, Serum, and Phagocytosis: In Vitro and In Vivo Studies
Authors: Olds John W. , Reed William P. , Eberle Betty , Kisch Alexander L.
Published: January 2020

The phagocytic-bactericidal capacity (PBC) of human polymorphonuclear leukocytes (PMNs) for strains of
Klebsiella
(K) and of
Enterococcus
(E) was unaffected in vitro by the presence of 100 μg of either hydrocortisone (HC) or of methylprednisolone (MP) per ml in the medium. At higher concentrations (500 to 2,000 μg/ml) both compounds impaired PBC-K and PBC-E, but the latter was less sensitive to steroid-induced inhibition. In addition to interfering with intracellular killing of both organisms by PMNs, 2,000 μg of HC per ml also inhibited ingestion of E, although not of K. Steroid-induced inhibition of PBC-K in vitro was completely abolished by increasing the concentration of serum used as opsonin. The PBC-K of human PMNs obtained 30 min after intravenous injection of 1 g of MP was unimpaired in vitro in the presence of 10 to 90% simultaneously obtained autologous serum containing 42 μg of MP per ml. These findings suggest that short-term, high-dosage administration of MP is unlikely to produce clinically significant impairment of intraleukocytic bacterial killing.
Relationship Between the Concentration of Bacteria in Saliva and the Colonization of Teeth in Humans
Authors: van Houte J. , Green D. B.
Published: January 2020

The relationship between the salivary concentration of bacteria and their number that can be recovered from tooth surfaces has been studied in 12 human subjects. The mean salivary concentration of naturally occurring
Steptococcus mutans
and lactobacilli, determined on selective media, was 3.7 × 10
5
and 3.8 × 10
5
colony-forming units (CFU) per ml, respectively. In subjects with salivary concentrations of
S. mutans
of about 10
4
CFU/ml or less or about 10
5
CFU/ml or less of lactobacilli, these organisms could not be isolated from cleaned teeth after 2 to 3 h of oral exposure. In experiments with streptomycin-labeled
S. sanguis
cells held in the mouth for 15 min, the minimal salivary concentration required for their recovery from the teeth was about 10
3
CFU/ml. Both
S. mutans
and lactobacilli were found to be highly localized on teeth. This evidence suggests that the concentrations of
S. mutans
and lactobacilli generally present in saliva are insufficient for the initiation of their firm attachment to relatively nonretentive tooth surfaces. The low efficiency of their intraoral spread, as suggested by their highly localized distribution on teeth, or of their transmission between subjects may be essentially due to the interrelated factors bacterial affinity and number of colony-forming units available for attachment.
In Vitro Lymphocyte Response to
Treponema refringens
in Human Syphilis
Authors: Musher Daniel M. , Schell Ronald F. , Knox John M.
Published: January 2020

The response of lymphocytes from patients with syphilis and normal subjects was studied in vitro by using phytohemagglutinin (PHA), pokeweed mitogen (PWM), streptolysin O (SLO), and a preparation of
Treponema refringens
. Normal lymphocytes exhibited a dose-response curve to treponemes. Although lymphocytes from patients with primary and secondary syphilis responded normally to PHA and PWM, their response to SLO was suppressed and they failed to show significant stimulation by treponemes. Serum from syphilitic patients did not affect normal lymphocytes, and culturing lymphocytes from patients with syphilis in normal serum did not restore their responsiveness. Six to 10 weeks after syphilitic patients had been treated, the degree of stimulation by treponemes was the same as for normal subjects. These data give indirect support to the hypothesis that immunological suppression occurs during active infection with
T. pallidum
.
Persistence of Regulation of Macromolecular Synthesis by
Escherichia coli
During Killing by Disrupted Rabbit Granulocytes
Authors: Elsbach Peter , Beckerdite Susan , Pettis Penelope , Franson Richard
Published: January 2020

Escherichia coli
incubated in balanced salt solution with glucose as a carbon source but no nitrogen source exhibit a marked step-up of macromolecular synthesis when various non-bactericidal tissue extracts, or fractions thereof, are added. When disrupted granulocytes that cause rapid loss of viability are added, a step-up is also observed; i.e., incorporation of labeled precursors into ribonucleic acid is stimulated more than 15-fold, and incorporation into protein and deoxyribonucleic acid about twofold. This stimulation of macromolecular synthesis is still evident 30 min after more than 95% of the
E. coli
have lost their ability to multiply. Stimulation by disrupted granulocytes of [
14
C]leucine incorporation into
E. coli
protein occurs over a wide range of leucine concentrations but is usually eliminated by adding a Casamino Acids mixture or another more complete medium. The substance(s) in tissue homogenates that trigger step-up is heat stable and dialyzable. Thus,
E. coli
exposed to the bactericidal and digestive components of disrupted granulocytes and no longer capable of division maintain their ability to regulate macromolecular synthesis in response to changes in nutritional conditions for at least 1 h.
Discrimination Between
Sporothrix schenckii
and
Ceratocystis stenoceras
Rhamnomannans by Proton and Carbon-13 Magnetic Resonance Spectroscopy
Authors: Travassos L. R. , Gorin P. A. J. , Lloyd K. O.
Published: January 2020

The proton and
13
C magnetic resonance (CMR) spectra of 10
Sporothrix schenckii
and three
Ceratocystis stenoceras
rhamnomannans were studied. On the basis of their CMR spectra, the rhamnomannans from
S. schenckii
strains could be classified into two major types, I and II, readily distinguishable from the polysaccharides formed at the same temperature (25 C) by
C. stenoceras
. Rhamnomannans from
S. schenckii
synthesized at 37 C gave CMR spectra (type III) differing from those of polysaccharides of types I and II and from those of
C. stenoceras
polysaccharides. The contention that
C. stenoceras
might be the perfect form of
S. schenckii
is not supported by the present data. A presumptive pathogenic mutant of
C. stenoceras
synthesized a type I rhamnomannan characteristic of
S. schenckii
, clearly differing from the rhamnomannans from
C. stenoceras
synthesized in the same conditions. Nuclear magnetic resonance spectroscopy revealed differences in the structures of the polysaccharides from these species not previously recognized by methylation analysis.
Age Dependence of Viral Expression: Comparative Pathogenesis of Two Rodent-Adapted Strains of Measles Virus in Mice
Authors: Griffin Diane E. , Mullinix Janice , Narayan Opendra , Johnson Richard T.
Published: January 2020

The pathogenesis of two rodent-adapted strains of measles virus was studied in 1- to 2-day-old suckling and 4-week-old weanling BALB/c mice. Both the mouse-adapted Edmonston (MAEd) strain and the hamster-neurotropic (HNT) strain caused necrotizing giant-cell encephalitis with a 90 to 100% mortality after intracerebral inoculation into suckling mice. After intracerebral inoculation into weanling mice, MAEd virus caused fatal disease in 20% of the mice; HNT virus caused fatal disease in 30%, but an additional 35% of these mice developed disease and then recovered. Even when mice were moribund there was little histological evidence of disease in weanling mice inoculated intracerebrally with either strain of virus. Fluorescent-antibody staining showed extensive measles virus antigen in the suckling mouse brain and focal areas of measles virus antigen in the weanling mouse brain. Infectious virus was recovered easily from the brains of suckling mice by plaquing on Vero cells, but no infectious virus could be recovered similarly from weanling mice. However, virus could be recovered by intracerebral inoculation of weanling mouse tissue homogenates into suckling animals. The immune response appeared to play no role in the recovery from infection or in these age-related differences in disease. It appears that maturation of the cells of the mouse central nervous system converted the production of measles virus from the infectious form in the suckling mouse to a primarily defective infection in the weanling mouse.
Release of Histamine from Hamster Mast Cells by Concanavalin A and Phytohemagglutinin
Authors: Hook W. A. , Dougherty S. F. , Oppenheim J. J.
Published: January 2020

Concanavalin A (Con A) and phytohemagglutinin (PHA) released histamine from hamster mast cells incubated in a serum-free medium. Concentrations of Con A and PHA approximating those optimal for transforming lymphocytes also released maximal amounts of histamine without apparent cytotoxicity. Higher concentrations of mitogen inhibited both lymphocyte transformation and histamine release. Incubation at 37 C for 15 min released histamine, although longer times were more effective. Supernatants from cultured hamster splenocytes stimulated with Con A also released histamine from added mast cells. However, the effect could be inhibited by the addition of 0.1 M methyl alpha-D-mannoside or by passing the spleen cell culture supernatants through Sephadex G-75 to remove Con A. This mitogen-induced release of mast cell histamine is therefore not mediated by a lymphokine but probably results from a direct interaction of mitogens with receptors on mast cells.
Correlates to Increased Lethality of Attenuated Venezuelan Encephalitis Virus Vaccine for Immunosuppressed Hamsters
Authors: Jahrling Peter B. , Dendy Earl , Eddy Gerald A.
Published: January 2020

Splenectomy or pretreatment of adult hamsters with cyclophosphamide (Cytoxan) increased the lethality of the TC-83 vaccine strain of Venezuelan encephalitis virus (VEE), inoculated subcutaneously, from 12% for normal hamsters to 75 and 76%, respectively. Neither splenectomy nor cyclophosphamide treatment significantly increased the lethality of Pixuna virus. Cytoxantreated (Cy) hamsters developed and maintained levels of TC-83 virus higher than normal infected controls in blood, brain, spleen, and femoral bone marrow; splenectomy had a similar but less intense effect. A severe myeloid necrosis of femoral bone marrow developed 4 to 9 days after TC-83 virus inoculation in 78% of the Cy hamsters and in 48% of the splenectomized (Sx) hamsters. In contrast, only 13% of normal TC-83-infected hamsters developed this lesion. Extensive hemorrhagic lesions in the olfactory lobes and adjacent areas of the brain also developed more frequently in Cy or Sx hamsters than in normal infected controls. Lethally infected hamsters developed and maintained a severe thrombocytopenia, which may be related to the bone marrow lesion and to the hemorrhagic manifestations of lethal VEE infections.
Rickettsial Infectious Antibody Complexes: Detection by Antiglobulin Plaque Reduction Technique
Authors: Kenyon Richard H. , McManus Albert T.
Published: January 2020

Rickettsia rickettsii
and
R. australis
formed infectious antibody complexes when reacted with homologous convalescent serum. The addition of antiglobulin to these complexes showed neutralization of plaques proportional to the concentration of rickettsial immune serum.
Scanning Density Gradient Isoelectric Focusing of
Staphylococcus aureus
Enterotoxins B and C
1
Authors: Yotis William W. , Catsimpoolas Nicholas , Bergdoll Merlin S. , Schantz Edward J.
Published: January 2020

Purified
Staphylococcus aureus
enterotoxins B and C
1
, the causative agents of staphylococcal food poisoning, were resolved into several components by scanning isoelectric focusing in sucrose density gradients in the absence and presence of 6 M urea and 5 mM dithiothreitol. The observed heterogeneity persisted in the denaturing medium, which suggests that the primary structure of protein enterotoxins B and C
1
may be partly responsible for the isoelectric point differences of the various forms. To our knowledge, the scanning isoelectric focusing patterns of staphylococcal enterotoxins B and C
1
are reported for the first time.
Partial Characterization of Aerolysin, a Lytic Exotoxin from
Aeromonas hydrophila
Authors: Bernheimer Alan W. , Avigad Lois S.
Published: January 2020

Conditions are defined for the production, in high titers, of an extracellular hemolytic toxin of
Aeromonas hydrophila
, here termed “aerolysin.” Substantial purification of the toxin was accomplished by means of salt fractionation, dialysis, and gel filtration, with a yield of 24% of the starting activity. Analysis of the product by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate revealed a single, heavy protein band and a number of faint protein bands. The estimated molecular weight of the heavy band (50,000) was in close agreement with that (53,000) of the substance responsible for hemolytic activity as determined by gel filtration. Purified aerolysin is a labile substance, apparently protein. It is not inactivated by any of several proteases under the conditions employed nor is it inhibited by any of several lipids tested. About 0.1 μg administered to mice intravenously is lethal. The physical properties of aerolysin show considerable resemblance to those described for the exotoxin of
Pseudomonas aeruginosa.
Serological Activity of Lipids of a T strain of
Mycoplasma
Authors: Romano Nino , Scarlata Giuliana
Published: January 2020

Complement-fixing activity of a T strain of
Mycoplasma
was found to be associated with its lipid components. Heat stability and lability of periodate and β-glucosidase treatments led to the conclusion that complement-fixing, active lipids had carboydrate determinants. Periodate treatment of chromatographic fractions of a chloroform-methanol extract showed that only antigens contained in the acetone fraction were periodate labile. Lipids also appeared to be involved in the passive hemagglutination, since the lipid fraction active in complement fixation also combined and blocked the action of antibodies which agglutinated sensitized erythrocytes with strain P108.
Antigenic Cross-Reaction Between Mouse Intestine and a Member of the Autochthonous Microflora
Authors: Foo M. C. , Lee Adrian
Published: January 2020

Antigenic cross-reaction has been demonstrated between homogenates of intestine taken from fetal mice and suspensions of a
Bacteriodes
species isolated from the large intestines of normal adult mice. This observation provides an explanation for the lack of immunological response observed in mice after antigenic stimulation with this member of the normal autochthonous intestinal flora of these animals.
Role of Typhoid Antigens in Protection and Pathogenicity for Mice
Authors: Diena B. B. , Baron L. S. , Johnson E. M. , Wallace R. , Ashton F. E.
Published: January 2020

Swiss white mice immunized with acetone-killed vaccines prepared from strains of
Salmonella typhosa, S. typhimurium
, and mouse-virulent
S. typhimurium
hybrids which had acquired, by conjugal genetic transfer, the
S. typhosa
antigens 9, Vi, and d were challenged with the
S. typhimurium
hybrids and with the
S. typhimurium
parent strain. The results of these experiments suggested that the
Salmonella
somatic antigens were important in conferring protection against death in this system. The
S. typhosa
Vi antigen did not appear to play any significant role in this protection. The
S. typhimurium
hybrids employed in these studies did not show any loss of mouse virulence as the consequence of acquisition of various combinations of the
S. typhosa
somatic, flagella, or Vi antigens, nor did
S. typhosa
hybrids which had acquired the somatic antigen of
S. typhimurium
show any increase in mouse virulence.
Influence of Sex and Age on Natural Resistance to St. Louis Encephalitis Virus Infection in Mice
Authors: Andersen Arthur A. , Hanson Robert P.
Published: January 2020

A difference was observed in susceptibility of adult male and female mice to St. Louis encephalitis (SLE) virus as measured by the death rate after intravenous challenge. Female mice that had susceptibility similar to that of males at 2 months of age had increased resistance to SLE virus at 3 and 4 months of age. The increased resistance occurred after sexual maturity, indicating that the resistance factor possibly was related to an aging process in the female. The susceptibility of male mice remained unchanged over the 2- to 4-month period. Neither pregnancy nor castration had any effect on resistance of adult mice to St. Louis encephalitis virus.
Effect of Bile Acids on the Intestinal Absorption of Endotoxin in Rats
Authors: Kocsár L. T. , Bertók L. , Várterész V.
Published: January 2020

The absorption of tritium-labeled
Escherichia coli
O89 Westphal-type endotoxin from the peritoneal cavity of rats was diminished by bile by 23% and by sodium deoxycholate by 47%, respectively. Practically, there is no endotoxin absorption from the intestinal tract of normal rats. The bile duct of rats was chronically cannulated for experimental purposes. A significant amount of perorally administered endotoxin absorbed from the intestinal canal into the blood in the rats treated thus. Absorption was demonstrated by the lethal effect of endotoxin on rats previously hypersensitized by lead acetate, and by the radioactivities found in the blood samples. The intestinal absorption of endotoxin in rats, rendered bile-deficient, may be prevented by sodium deoxycholate. Supported by their experimental findings, we emphasize the important role of bile acids in the defense mechanism of the macroorganism against bacterial endotoxins.
Sodium-Stimulated Transport of Glutamate in
Escherichia coli
Authors: Frank Leonard , Hopkins Irene
Published: January 2020

Wild-type
Escherichia coli
B grew poorly on glutamate as the sole carbon source, except at very high concentrations of the amino acid. The addition of sodium ion markedly stimulated the growth. It had the same effect in a mutant of
E. coli
B selected for the ability to grow at low glutamate concentrations. Sodium ion also potentiated growth inhibition by analogues of glutamate. The uptake of glutamate by nongrowing cells of the mutant was markedly stimulated by sodium ion in the presence of an energy source, chloramphenicol, and arsenite, which retarded glutamate degradation.
Biological Studies with α-Dehydrobiotin
Authors: Hanka L. J. , Reineke L. M. , Martin D. G.
Published: January 2020

A growing culture of
Streptomyces lydicus
converted biotin-
14
C to α-dehydrobiotin-
14
C. The conversion was demonstrated by isolating crystalline α-dehydrobiotin-
14
C from fermentation liquors supplemented with biotin-
14
C. The addition of pimelic acid-
14
C to the growing culture did not produce any radioactive α-dehydrobiotin. α-Dehydrobiotin did not substitute for biotin in
Lactobacillus plantarum
or in
Saccharomyces cerevisiae
. Antimicrobial activity of α-dehydrobiotin was abolished by avidin. α-Dehydrobiotin appears to be different from several biotin vitamers described in the literature. It is concluded that α-dehydrobiotin is a product of biotin catabolism in
S. lydicus
.
Ultraviolet Micrography of Penetration of Exogenous Cytochrome
c
into the Yeast Cell
Authors: Svihla G. , Dainko J. L. , Schlenk F.
Published: January 2020

Candida utilis
and
Saccharomyces cerevisiae
in water suspension were found to be very sensitive to exogenous cytochrome
c
. The protein was taken up by the cells, and the viable count was reduced to a few per cent of the initial value. Micrography at 405 nm revealed penetration of cytochrome
c
into the interior of the cell. The cytoplasmic membrane lost its capacity to retain intracellular constituents, and ultraviolet-absorbing compounds were released into the medium. When budding cells were subjected to treatment with cytochrome
c
, the mother cells were found to be more susceptible than the buds. Phosphate buffer protected the cells and spheroplasts against cytochrome
c
.
Experimental Arthritis in Mice with
Mycoplasma pulmonis
Authors: Barden Jerri A. , Tully Joseph G.
Published: January 2020

A
Mycoplasma pulmonis
strain, recovered from the arthritic joints of mice employed in the serial passage of a chemically induced tumor, was found to be arthritogenic for mice under experimental conditions. Some joint involvement occurred in all mice challenged intravenously with this strain, and
M. pulmonis
was recovered frequently from the enlarged joints. The arthritis was migratory, appearing first in the radiocarpal joints and later in the tibiotarsal joints. There was little evidence of a generalized mycoplasmal infection as a consequence of the experimental challenge. Histopathologically, the early stages of the infection in the joints was characterized by an inflammatory response in the synovium and periarticular tissues. Exudate in the joint space contained about equal numbers of polymorphonuclear and mononuclear cells. The polyarthritis resolved slowly, but some residual joint enlargement was noted for as long as 4 months. Two other
M. pulmonis
strains were also observed to be arthritogenic for mice. Rats were not susceptible to
M. pulmonis
challenge. Characteristics of the nonsuppurative
M. pulmonis
arthritis in mice were compared to
M. arthritidis
joint infections in rats.
Heterogeneity Between Two Mouse-Toxic Protein Polymers from
Pasteurella pestis
Indicated by Electrophoresis Patterns in a Phenol-Acetic Acid-Urea Gel System
Authors: Montie Thomas C. , Montie Diane B.
Published: January 2020

Highly purified plague murine toxins A or B dissociate to form single uncommon polypeptide bands and another polypeptide band common to both toxins.
Ileal Loop Fluid Accumulation and Production of Diarrhea in Rabbits by Cell-free Products of
Clostridium perfringens
Authors: Duncan Charles L. , Strong Dorothy H.
Published: January 2020

The ability of cell extracts and culture filtrates of various strains of
C. perfringens
to produce ileal loop fluid accumulation and overt diarrhea in rabbits was tested. Good correlation was obtained in the ability of whole cells and a toxic factor (present in cell extracts and concentrated culture filtrates) to produce both fluid accumulation in ileal loops and diarrhea when injected into the normal ileum of the rabbit. The toxic factor was present in cell-free preparations when cells were grown in a sporulation medium, but not when they were grown in an asporogenic medium. The factor was shown to be heat labile, nondialyzable, and was inactivated by Pronase but not by trypsin, lipase, or amylase. Loss of activity occurred at
p
H 1.0, 3.0, 5.0, and 12.0.
Ultrastructural Changes During Germination of
Dictyostelium discoideum
Spores
Authors: Cotter David A. , Miura-Santo Leatrice Y. , Hohl Hans R.
Published: January 2020

Spores of
Dictyostelium discoideum
undergo significant changes in fine structure during germination. The mitochondria progressively become less dense and lose their peripherally attached ribosomes, and the tubuli become more pronounced as germination proceeds. During this period, the three-layered spore wall breaks down in two stages: first, the outer and middle layers are ruptured as a unit, and, second, the inner wall is breached. Crystals and dark (lipid) bodies disappear shortly before or during emergence of the myxamoebae. Autophagic vacuoles are found in dormant spores and throughout the entire germination process. The addition of cycloheximide to germinating spores inhibited the loss of the crystals and dark (lipid) bodies. In addition, the drug inhibited the breakdown of the inner wall layer. Cycloheximide did not prevent the formation of the water expulsion vesicle or the apparent function of the autophagic vacuoles.
Ultrastructural Changes in Bacteria Isolated from Cases of Leprosy
Authors: Freer John , Kim Kwang S. , Krauss M. R. , Beaman Lovelle , Barksdale Lane
Published: January 2020

One of two groups of rod-shaped bacteria (bacilli) isolated from cases of human leprosy have been found, under certain cultural conditions, to give rise to unusual phenotypes. In electron micrographs of ultrathin sections and negatively stained whole cells of these osmotically fragile bacteria, ultrastructural anomalies are apparent and seem to arise from disorder in the process(es) of septum formation or cell envelope biosynthesis or both. Two of the four strains examined are related toCorynebacterium acnes.
Vibrio cholerae
Enterotoxin in Miniature Pigs
Authors: Heckly Robert J. , Wolochow H. , Christiansen C.
Published: January 2020

Miniature pigs appear to be less sensitive than rabbits to cholera toxin introduced into segments of the ileum.
Metabolism of Phloridzin by
Erwinia herbicola
: Nature of the Degradation Products, and the Purification and Properties of Phloretin Hydrolase
Authors: Chatterjee A. K. , Gibbins L. N.
Published: January 2020

Erwinia herbicola
Y46 degrades phloridzin to yield phloretin, phloroglucinol, and phloretic acid, when grown on defined medium containing phloridzin as the sole source of carbon. The identities of the intermediates isolated from culture filtrates were established by co-chromatography and by ultraviolet absorption spectra. Only 3 of 11 strains of this species, and none of the 12 species of bacterial phytopathogens tested could effect this breakdown. Some of the latter organisms possessed β-glucosidase activity which liberated
d
-glucose from phloridzin. The enzyme phloretin hydrolase was purified from cells of
E. herbicola
Y46 grown on Yeast Beef Broth, by treatment of crude extracts with protamine sulfate, ammonium sulfate precipitation, elution from calcium phosphate gel, elution from diethylaminoethyl-cellulose, and concentration by ultrafiltration. The final preparation was free of β-glucosidase, had a specific activity of 213 units per mg of protein, and represented a 142-fold purification over the crude extract. The enzyme had a
p
H optimum of 6.7 to 6.8, and produced only phloroglucinol and phloretic acid as products of phloretin breakdown, there being an equimolar relationship between the cleavage of phloretin and the formation of the products. The Michaelis constant (K
m
) for the enzyme with phloretin as substrate was 3.8 × 10
−5
m
, and the enzyme was sensitive to Hg
2+
and Cu
2+
ions. Phloroglucinol, phloretic acid,
p
-chloromercuribenzoate and iodoacetamide were without effect on the activity. The enzyme did not react with phloridzin, naringin, or naringenin. The physiological significance of the results is discussed.
Control of Dimorphism in a Biochemical Variant of
Candida albicans
Authors: Mardon D. , Balish E. , Phillips A. W.
Published: January 2020

The cellular morphology of a biochemical variant of
Candida albicans
could be controlled by the ratio of carbon dioxide to oxygen in the culture system or by individual amino acids. Predominantly pseudohyphal morphology was observed (i) at a CO
2
to O
2
ratio of 2:1 and (ii) without the addition of carbon dioxide, when either glycine,
d
- or
l
-ornithine,
l
-serine,
l
-methionine,
l
-phenylalanine, or
l
-tyrosine was the sole nitrogen source in the culture medium. When ammonium chloride, ammonium sulfate,
l
-glutamic acid,
l
-glutamine, or
l
-proline was the nitrogen source, yeastlike growth was observed in the presence or absence of CO
2
. More adenosylmethionine was present in pseudohyphal than in yeastlike cells, and pseudohyphal cell wall preparations contained less methionine than cell walls from the yeastlike form. These results suggest a correlation between sulfur amino acid metabolism and dimorphism.
Inhibitory Effect of Penicillin on Proline Synthesis in
Escherichia coli
Authors: Baich Annette
Published: January 2020

The production of glutamic γ-semialdehyde, an intermediate in the synthesis of proline, was inhibited in
Escherichia coli
by physiological concentrations of penicillin. Sucrose (0.6
m
) and sodium chloride (0.1
m
) prevented penicillin inhibition of glutamic γ-semialdehyde synthesis. Cells which were in the stationary phase, or which had been permitted to metabolize without growth, were insensitive to the effects of penicillin on glutamic γ-semialdehyde synthesis.
Observations on Membranes of
Mycoplasma laidlawii
Strain B
Authors: Smith P. F. , Koostra W. L. , Mayberry W. R.
Published: January 2020

The cytoplasmic membrane of
Mycoplasma laidlawii
strain B is solubilized by anionic and nonionic detergents, succinylation, phospholipase A, alkaline phosphatase, trypsin, and chymotrypsin. Cationic detergents are without effect, as are chelating agents, even in the presence of high concentrations of monovalent cation. The detergent-solubilized membrane exhibits one peak in the analytical ultracentrifuge, but the sedimentation coefficient is dependent upon concentration of detergent. Simple dialysis does not remove all of the sodium dodecylsulfate except from lipid-depleted membrane particles. Membranes bind sodium dodecylsulfate but acetone powders of membranes do not. Sulfated alcohols with chain lengths of C
14
and C
16
are more tightly bound than dodecylsulfate. A constant amount of di- and trivalent cation is bound by the membrane upon aggregation. Only a portion of this cation is removable with chelating agents. No chelating agent is bound by these aggregates. A portion of the lipid-depleted membrane particles is solubilized by negatively charged lipids and detergents, giving rise to aggregates in the presence of divalent cation. Fractionations of detergent-solubilized membranes by preparative gel electrophoresis and ammonium sulfate were inconclusive. Density gradient centrifugation of succinylated membranes yielded at least five fractions which exhibited homogeneity by ultracentrifugation. Analytical gel electrophoresis of these fractions demonstrated heterogeneity. The composition of these five fractions suggested separation of protein from lipid.
Isozymes of β-Glucosidase in
Dictyostelium discoideum
Authors: Coston M. Bruce , Loomis W. F.
Published: January 2020

The activity of β-glucosidase (EC 3.2.1.21) in extracts of
Dictyostelium discoideum
was investigated. The specific activity increased early in development, declined during pseudoplasmodium formation, and increased again during sorocarp formation. The β-glucosidase which was present in growing amoebae and during the first stages of multicellular development was electrophoretically distinct from the enzyme which accumulated during the final stages of morphogenesis. Ribonucleic acid synthesis and protein synthesis during development were required for the accumulation of the later isozyme. Analysis of β-glucosidase activity in a number of morphological mutants suggests that the enzyme which accumulates late in morphogenesis is developmentally controlled.
Transketolase Mutants ofEscherichia coli
Authors: Josephson Betty L. , Fraenkel D. G.
Published: January 2020

Transketolase mutants have been selected after ethyl methane sulfonate mutagenesis ofEscherichia coli. These strains are unable to grow on any pentose and, in addition, require a supplement of aromatic amino acids or shikimic acid for normal growth on any other carbon source. Revertants are normal in both respects and also contain transketolase. Transketolase mutants do not require exogenous pentose for growth. Preliminary genetic mapping of the locus is presented.
Streptolydigin, an Inhibitor of Oxidative Phosphorylation in Rat Liver Mitochondria
Authors: Reusser Fritz
Published: January 2020

Streptolydigin interferes with oxidative phosphorylation in rat liver mitochondria. The agent acts primarily as an uncoupler of respiration-associated phosphorylation but also impairs respiration to various degrees depending on the substrate. Streptolydigin partially inhibits electron flow at a point past the cytochrome
b
and prior to the cytochrome
c
reduction site. Streptolydigin also inhibits the function of the enzyme ribonucleic acid polymerase in whole bacterial cells and cell-free systems. The streptolydigin concentrations that cause effective inhibition of ribonucleic acid polymerase in cell-free systems are approximately 10 times less than those required to inhibit oxidative phosphorylation in mitochondria.
Glucose Degradation in
Clostridium perfringens
Type A
Authors: Groves D. J. , Gronlund Audrey F.
Published: January 2020

Cell-free extracts of
Clostridium perfringens
were found to contain all the enzymes of the Embden-Meyerhof pathway of glycolysis in addition to lactic acid dehydrogenase and the pyruvate-clastic system. Neither glucose-6-phosphate dehydrogenase nor 6-phosphogluconate dehydrogenase activities could be demonstrated, suggesting the absence of the conventional hexose-monophosphate pathway in this organism.
Double-Bond Requirement in a Fatty Acid Desaturase Mutant of
Saccharomyces cerevisiae
Authors: Wisnieski Bernadine J. , Keith Alec D. , Resnick Michael R.
Published: January 2020

A fatty acid Δ
9
-desaturase mutant of yeast was analyzed to establish the specificity of the fatty acid structural requirement. Several double-bond-containing and substituted fatty acids were tested. It was concluded that the presence of a Δ
9
cis
double bond is necessary for growth. The need for a specific chain length or a specific number of double bonds, or for both, is more flexible. Tracer-containing 16:1Δ
9
cis
, 18:1Δ
9
cis
, 18:2Δ
9,12
cis,cis
and 18:3Δ
9,12,15
all
cis
revealed that each of these growth-supporting components, once taken up, was not converted into other fatty acids. Concentration effects on doubling time were also considered.
Resistance of
Escherichia coli
to Penicillins VI. Purification and Characterization of the Chromosomally Mediated Penicillinase Present in
ampA
-Containing Strains
Authors: Lindström E. Börje , Boman Hans G. , Steele Barbara B.
Published: January 2020

The chromosomally mediated penicillinase present in three strains of
Escherichia coli
K-12 has been purified and characterized. Two of the strains carried the
ampA
gene and the third the wild-type allele. The purification involves release of the enzyme by spheroplast formation, dialysis, chromatography on sulfoethyl cellulose, and chromatography on hydroxylapatite. Enzyme from the two mutants appeared homogeneous in polyacrylamide gel electrophoresis. Enzyme from the wild-type strain gave two bands. Immunologically, the enzymes from all three strains were identical. Ultracentrifugation gave a homogeneous peak with a sedimentation coefficient of 3.4
S
. Gel filtration gave an estimated molecular weight of 29,000. The N-terminal amino acid residue was found to be alanine. Complete amino acid analysis showed a lack of cysteine. Ultraviolet spectra were recorded at three different
p
H values. The extinction coefficient at 280 nm is 21.0 for a 1% solution at
p
H 6.8. The optimal
p
H is 7.3. With enzyme from one of the resistant mutants, the following
K
m
and turnover number values were obtained: for penicillin G, 12 μ
m
and 2,080; for
d
-ampicillin, 6 μ
m
and 83; for cephalosporin C, 217 μ
m
and 18,400. The effect of different salts on the enzyme activity was tested. Under many conditions the enzyme was found to be unstable.
Differentiation Within the Bacterial Flagellum and Isolation of the Proximal Hook
Authors: Abram Dinah , Mitchen J. R. , Koffler Henry , Vatter A. E.
Published: January 2020

Purified and crude flagellar isolates from cells of
Bacillus pumilus
NRS 236 were treated with acid, alcohol, acid-alcohol, or heat, and were examined electron microscopically in negatively stained and shadow-cast preparations. Under certain conditions, each of these agents causes the flagella to break between the proximal hooks and the spiral filaments. In such preparations, filaments are seen in various stages of disintegration, whereas hooks of fairly constant length retain their integrity and morphological identity. When crude isolates of flagella are treated under these conditions, the hooks remain attached to membrane fragments or bear basal material. These findings substantiate previous structural observations that led to the view that the proximal hook is a distinct part of the bacterial flagellum and further confirm that the hook is tightly associated with basal material and the cytoplasmic membrane. It appears that the hook is a polarly oriented structure, and that the interactions between the hook and the basal material or the cytoplasmic membrane are different from those between the hook and the filamentous portion of the organelle. Moreover, both types of interaction apparently differ still from those by which the flagellin subunits are held together in the flagellar filament. Hooks were isolated by exploiting the differences in relative stability shown by the various morphological regions of the bacterial flagellum.