Ultraviolet microscopy of purine compounds in the yeast vacuole

Svihla, G. (Argonne National Laboratory, Argonne, Ill.), J. L. Dainko, and F. Schlenk. Ultraviolet microscopy of purine compounds in the yeast vacuole. J. Bacteriol. 85:399-409. 1962.-Yeast cells (Candida utilis and Saccharomyces cerevisiae) suspended in nitrogen-free medium were exposed to various ultraviolet-absorbing biological compounds, particularly nucleic acid constituents. Ultraviolet photomicrography was used to locate these substances in the cells. Purines were taken up readily and concentrated in the vacuoles of C. utilis but not of S. cerevisiae. Crystallization occurred, as observed earlier by other techniques. Neither organism assimilated pyrimidine bases, or purine or pyrimidine nucleosides, at a detectable rate. From the selective uptake and release of some purine derivatives, it can be concluded that the properties of the vacuolar membrane and the cytoplasmic membrane differ in several respects.

Production of tolerance to the toxicity of Candida albicans by nonfungal materials

Hasenclever, H. F. (National Institute of Allergy and Infectious Diseases, Bethesda, Md.) and W. O. Mitchell. Production of tolerance to the toxicity of Candida albicans by nonfungal materials. J. Bacteriol. 84:1325-1329. 1962.-Tolerance in mice to the toxic manifestations of viable Candida albicans cells was elicited by injections of Salmonella enteritidis or S. typhosa lipopolysaccharides, or complete Freund's adjuvant. The greatest host stimulation occurred when the lipopolysaccharides were given 1 or 6 days before intravenous challenge. The highest level of tolerance produced by intraperitoneal preinfection with C. albicans was found when the yeast cells were injected 6 days before challenge. Older mice appeared to require larger amounts of endotoxin to demonstrate toxicity tolerance. Protection in mice that received both lipopolysaccharide injections and C. albicans intraperitoneal preinfection was slightly higher than in those mice given only the individual components.

Spheroplasts of the yeast Candida utilis

Svihla, G. (Argonne National Laboratory, Argonne, Ill.), F. Schlenk, and J. L. Dainko. Spheroplasts of the yeast Candida utilis. J. Bacteriol. 82:808-814. 1961.-The formation and properties of spheroplasts of the yeast Candida utilis, produced by digestion of the cell walls with snail gut juice (Helix pomatia) in isotonic medium, were studied by phase, interference, and ultraviolet microscopy, and tracer techniques. Cells cultivated in the presence of l-methionine, S-methyl-l-methionine, and l-homocysteine (5 mumoles/ml) were more susceptible to enzyme action than ordinary cells. These cells contain increased amounts of S-adenosylmethionine in the vacuole which facilitates ultraviolet microscopy. Spheroplasts are stable in 0.6 m KCl containing 0.04 m phosphate, but are disintegrated by water, sonic vibration, or ultraviolet irradiation. Exposure in isotonic medium to 6 x 10(4) erg/mm(2) energy at 253 mmu breaks the cytoplasmic membrane and liberates the vacuole with membrane intact. The vacuolar membrane may be broken with about three times the initial dose of ultraviolet.

POLYVINYL-PYRROLIDONE-IODINE: AN ASSESSMENT OF ANTIBACTERIAL ACTIVITY

Polyvinyl-pyrrolidone-iodine complex (PVP-I) was shown to have a rapid disinfectant activityin vitroagainst vegetative bacteria and fungi and against vegetativeTrichomonas. The presence of organic matter had a slight delaying effect on the killing time. Bacterial spores survived in PVP-I for 17 hr. and fungal spores for 1½ hr. Used as an agent for pre-operative preparation of the skin, PVP-I was more efficient than others tested, rendering the skin surface sterile even when heavily contaminated, and keeping it so for 1 hr. None of the staining characteristics of iodine were noted since PVP-I was easily removed by water. Two individuals, known to be iodine sensitive, developed mild iodism after application of PVP-I.

The authors are indebted to the staff of the hospital for their co-operation; and to Berk Pharmaceuticals Limited for supplies of PVP-I, manufactured by them as Betadine (Povidone-iodine B.P.).

IMMUNOLOGIC STUDIES IN HUMAN ORGAN TRANSPLANTATION. I. OBSERVATION AND CHARACTERIZATION OF SUPPRESSED CUTANEOUS REACTIVITY IN UREMIA

Twenty-eight patients with chronic renal diseases and uremia were investigated with respect to their cutaneous responsiveness to a panel of antigens expected to elicit immediate and delayed hypersensitivity reactions. Compared to a control group, there was a marked decrease in the incidence of responses of both types. Eighteen patients received renal allografts from members of the control group and were available for restudy in the postoperative period prior to the institution of adrenal steroid therapy. Each recipient acquired delayed responsiveness with specificity identical with that of the kidney donor. The donor group was reactive to 49 antigens to which the recipients were non-reactive preoperatively. Postoperatively, 40 of these reactivities were observed in the recipients. This successful demonstration of the transfer of immunologically competent tissue in association with renal transplantation indicates that the cause of depressed cutaneous hypersensitivity in uremia is not an inability of the skin per se to react.

CONJUNCTIVA CONTAINS FACTOR INHIBITING GROWTH OF CANDIDA ALBICANS

Intact conjunctiva and conjunctival extracts have a strong inhibitory effect upon Candida albicans. The fungistatic effect is not attributable to antimetabolic action and is not caused by lysozyme or tears, neither of which inhibit growth and viability of Candida albicans.

THE INCIDENCE OF THE SEROLOGICAL GROUPS OF CANDIDA ALBICANS IN SOUTHERN ENGLAND

Cultures ofC. albicanshave been classified into two groups by means of a double diffusion precipitin test employing rabbit antisera and polysaccharide extracts. In the present series it has been found that 75% of cultures belong to group A and 25% to group B, and it is suggested that the higher incidence of group B strains occurring in the sputum of hospital in-patients with chest disease may be the result of reinfection by attenuated forms which persist in the environment.

My thanks are due to many colleagues who provided me with the strains ofC. albicans, and to Prof. H. Hare for helpful criticism in the preparation of this paper.

IN VITRO BIOLOGICAL ACTIVITY OF CEPHALOTHIN

Chang, Te-Wen (Tufts University School of Medicine, Boston, Mass.) and Louis Weinstein. In vitro biological activity of cephalothin. J. Bacteriol. 85:1022-1027. 1963.-Cephalothin is a "broad-spectrum" antibiotic active, in low concentrations, against Diplococcus pneumoniae, Streptococcus pyogenes, and Staphylococcus aureus. Shigella, Salmonella, and Proteus mirabilis were the most sensitive of the gram-negative organisms. Escherichia coli and Aerobacter aerogenes were suppressed to a lesser degree, whereas Pseudomonas aeruginosa and Herellea were highly resistant. Penicillin-sensitive and -resistant strains of S. aureus were equally susceptible to cephalothin. Exposure to increasing concentrations of the drug very frequently led to the development of resistance in gram-negative organisms; this was observed less often with S. aureus. Cephalothin stimulated the production of penicillinase by staphylococci, which remained sensitive to the cephalosporanic acid derivatives despite repeated subculture in increasing concentrations of the agent. Cephalothin was not inhibited by penicillinase. This antibiotic was more toxic to cultures of human amnion and mouse embryo cells than benzyl penicillin G but was less injurious than oxytetracycline, chlortetracycline, and demethylchlortetracycline; tetracylcine produced about the same degree of cellular damage as cephalothin.

MODE OF ACTION OF MYCOBACILLIN, A NEW ANTIFUNGAL ANTIBIOTIC

Banerjee, N. (Calcutta University, Calcutta, India) and S. K. Bose. Mode of action of mycobacillin, a new antifungal antibiotic. J. Bacteriol. 86:387-391. 1963.-Mycobacillin agglutinates cells of Candida albicans. The agglutination reaction was found to be dependent on temperature, pH level, etc. Experiments have also been planned to assess whether agglutination and antifungal action are causally related. It appears that agglutination may be a secondary late effect of the action of the drug, not causally related to but simply associated with the primary cause responsible for antifungal action.

OBLIGATELY PSYCHROPHILIC YEASTS FROM THE POLAR REGIONS

Sixty-seven pure cultures of psychrophilic bacteria and yeasts were isolated from polar ice, snow, soil, and other materials. Low temperatures were maintained during all phases of the isolation procedure to avoid possible destruction of obligate psychrophiles. Four of the cultures, all yeasts, proved to be obligate psychrophiles. Three are species of Candida and one of Torulopsis. They grew in the range of 0 °C to 20 °C and the optimum growth temperature was 15 °C. They died rapidly when exposed to temperatures of 30 °C or 40 °C.The rate of fermentation of glucose by psychrophilic Candida sp. P16 was higher than that of mesophilic Saccharomyces cerevisiae at temperatures below 25 °C. At and above 25 °C, this rate relationship was reversed and at 35 °C all fermentative activity of the psychrophilic yeast was destroyed while that of the mesophile was maximal. Oxidative activity of Candida sp. P16 was much less sensitive to 35 °C, which suggests that fermentation and oxidation proceed by different pathways.The extent of occurrence of obligately psychrophilic microorganisms in nature is discussed.

IN VITRO INHIBITION OF YEAST GROWTH BY MOUSE ASCITES FLUID AND SERUM

Summers, Donald F. (National Institute of Allergy and Infectious Diseases, Bethesda, Md.), and H. F. Hasenclever. In vitro inhibition of yeast growth by mouse ascites fluid and serum. J. Bacteriol. 87:1-7. 1964.-A nondialyzable heat-stable factor(s) present in experimentally produced mouse ascites fluid and in serum from these ascitic mice was shown to inhibit the invitro growth of several yeasts. The inhibitory activity was almost totally abolished by trypsin treatment of the ascites fluid, and was progressively diminished by repeated adsorption of the ascites fluid by heat-killed Candida albicans cells. A close relationship was shown to exist between growth inhibition by ascites fluid and concentration of free iron or nutrients in the growth medium. Increased concentration of nutrients or free iron caused diminution of inhibitory activity.

ACTION OF RIBONUCLEASE PREPARATIONS ON VIABLE YEAST CELLS AND SPHEROPLASTS

Schlenk, F. (Argonne National Laboratory, Argonne, Ill.), and J. L. Dainko. Action of ribonuclease preparations on viable yeast cells and spheroplasts. J. Bacteriol. 89:428-436. 1965.-Recrystallized pancreatic ribonuclease releases more than half of the ultraviolet-absorbing cellular constituents of Candida utilis and Saccharomyces cerevisiae. The presence of salts and buffer interferes with the action of the enzyme on the cytoplasmic membrane, and intracellular constituents show a similar inhibitory effect. Polymerized ribonuclease and conformational isomers cannot penetrate the pores of the yeast cell wall, but they are effective on the membrane of spheroplasts. All forms of the enzyme interfere strongly with the viability of the cells.

SUGAR TRANSPORT IN A PSYCHROPHILIC YEAST

Cirillo, Vincent P. (Seton Hall College of Medicine and Dentistry, Jersey City, N.J.), Peter O. Wilkins, and Joseph Anton. Sugar transport in a psychrophilic yeast. J. Bacteriol. 86:1259-1264. 1963.-The mechanism and temperature characteristic for sugar transport were compared in a psychrophilic and a mesophilic yeast. Between 0 and 10 C, glucose utilization, glucosamine accumulation, and sorbose transport showed a very high temperature characteristic in the mesophile (mu = 50,000) compared with the psychrophile (mu = 12,000). Hexokinase activity in cell-free extracts from both yeasts, however, showed the same low temperature characteristic (mu = 15,000). Although the temperature characteristic for sugar transport was markedly different for the mesophile and the psychrophile, sugar transport in both yeasts met the criteria for carrier-mediated facilitated diffusion.

EVALUATION OF DISINFECTANTS FOR HOSPITAL HOUSEKEEPING USE

A use-dilution procedure and screening method are proposed to aid the hospital bacteriologist in selecting the most effective disinfectants. Sixteen disinfectants were tested with and without organic material on six different organisms. Sporadic results usually obtained with quaternaries tested by the procedure of the Association of Official Agricultural Chemists (AOAC) were eliminated by the methods of this study. The use-dilution procedure employs the material upon which the disinfectant is to be used, rather than stainless steel, as in the AOAC use-dilution test. The importance of testing each disinfectant against several organisms and in the presence of organic material is discussed.

CYTOLOGY OF CANDIDA ALBICANS AS INFLUENCED BY DRUGS ACTING ON THE CYTOPLASMIC MEMBRANE

Gale, Glen R. (Veterans Administration Hospital, Durham, N.C.) Cytology of Candida albicans as influenced by drugs acting on the cytoplasmic membrane. J. Bacteriol. 86:151-157. 1963.-An electron microscopic comparison was made of the cytological responses of Candida albicans to benzalkonium chloride, amphotericin B, and filipin, all of which are thought to exert their primary pharmacological actions on the cytoplasmic membrane of susceptible microorganisms. After 5 to 15 min of exposure to benzalkonium chloride, most of the cytoplasm became less dense, and intact nuclei, mitochondria, or intracytoplasmic membranes were not observed. The remaining dense cytoplasm contained numerous small holes. The polyene antifungal agents, amphotericin B and filipin, caused a reduction in cytoplasmic density, but had no observable effect on nuclei or mitochondria. The intervals before onset of changes induced by the polyene agents correlated with the known time-dependent binding of these drugs by cells, and the decreased electron scattering induced by all three agents was compatible with their known abilities to cause a loss of integrity of the cytoplasmic membrane with resultant leakage of cytoplasmic components. No consistent morphological effect of any of these drugs on the cytoplasmic membrane could be shown.

IMMUNOLOGICAL AND TOXIC DIFFERENCES BETWEEN MOUSE-VIRULENT AND MOUSE-AVIRULENT CANDIDA ALBICANS

Isenberg, Henry D. (Long Island Jewish Hospital, New Hyde Park, N.Y.), Jona Allerhand, James I. Berkman, and Dorothy Goldberg. Immunological and toxic differences between mouse-virulent and mouse-avirulent Candida albicans. J. Bacteriol. 86:1010-1018. 1963.-The differences between mouse-avirulent and -virulent strains of Candida albicans reside at least in part in cell surface materials which can be extracted with solvents such as ethanolethyl ether and phenol. These extracts are complex haptens which behave like endotoxins in mice and rabbits. Antibodies produced against intact and extracted cells show some strain specificity in agglutination and precipitin reactions, but underline primarily the differences between the virulent and avirulent variants. The chemical constitution of the extracted complex haptens suggests that the toxic or virulent principles are polysaccharide in nature and that the avirulent strain substitutes fats and lipids for some polysaccharides on their cell surface.

DEVELOPMENT OF RESISTANCE TO POLYENE ANTIBIOTICS IN CANDIDA ALBICANS

Hebeka, Elias K. (Rutgers, The State University, New Brunswick, N.J.), and Morris Solotorovsky. Development of resistance to polyene antibiotics in Candida albicans. J. Bacteriol. 89:1533-1539. 1965.-Strains of Candida albicans resistant to the polyenes candidin and amphotericin B, but not to nystatin, were developed by sub-culturing the organism in gradually increasing concentrations of the antibiotic in broth on a shaker, or by repeated transfer on gradient plates. Demonstration of resistance on solid media was best observed when a purified agar, Ionagar no. 2 (Oxoid), was used in preparing the medium. Strains that were 150-fold resistant to candidin, and 4-, 16-, 45-, and 60-fold resistant to amphotericin B were developed. The degree of resistance depended on the strain, the type of medium, and, most importantly, on the antibiotic used. The polyenes candidin, amphotericin B, nystatin, and fungimycin and the nonpolyenes griseofulvin and eulicin were used to extend the scope of study of cross-resistance. Cells rendered resistant to candidin were also resistant to amphotericin B, but not to nystatin, fungimycin, or griseofulvin. Cells rendered resistant to amphotericin B showed cross-resistance to candidin, but not to nystatin, fungimycin, or griseofulvin. Candidinor amphotericin B-resistant strains were more sensitive to eulicin than their parent strains. Increased resistance to candidin or amphotericin B was accompanied by a decrease in virulence for mice, the rate of growth, the ability to reduce bismuth sulfite, and by an increased tendency for filamentation. No change in the ability to form chlamydospores was noticed.