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PubMed2005

Fungicidal activity of human peripheral blood leukocytes against Paracoccidioides brasiliensis yeast cells.

Although epidemiological findings suggest that normal humans are resistant to Paracoccidioides brasiliensis infection, the host defense mechanisms against this fungus have not been fully understood. Here we examined human leukocytes for antifungal activity against yeast cells of this fungus, using an improved mycological culture medium with high plating efficiency for the yeast cell. In an attempt to minimize the impairment of leukocyte activities during the isolation process, leukocytes removed by centrifugation from a buffy coat of peripheral blood were used in the antifungal assay without further fractionation. The leukocytes thus prepared effectively killed P. brasiliensis yeast cells within the first 4 h of co-culture. Adding interferon-gamma (37 ng/ml), granulocyte-macrophage colony-stimulating factor (5 ng/ml), interleukin (IL)-1beta (12 ng/ml), or IL-4 (12 ng/ml) to the assay system enhanced the leukocyte antifungal (growth inhibitory) activity by 48 h. By contrast, addition of IL-8 (50 ng/ml) impaired the leukocyte activity. Tumor-necrosis factor-alpha (50 ng/ml) or IL-10 (25 ng/ml) had no effect in this respect. Dexamethasone (1 micromol/l) reduced the antifungal activity of leukocytes. This is the first demonstration that human leukocytes are able to effectively kill yeast cells of P. brasiliensis.

Humans↗
PubMed1997

Design of novel analogue peptides with potent fungicidal but low hemolytic activity based on the cecropin A-melittin hybrid structure.

In order to design synthetic peptides with potent antifungal activity but low cytotoxic activity under physiological conditions, several analogues of the previously reported cecropin A (CA)-melittin (ME) hybrid peptide, CA(1-8)-ME(1-12), were synthesized. These analogues were designed by analysis of the alpha-helical wheel diagram of CA(1-8)-ME(1-12). Antifungal activities were measured by growth inhibition of the yeast Trichosporon beigelii and by hemolytic assay with human red blood cells, respectively. Substitution of Thr for Lys at position 18 and 19 of CA(1-8)-ME(1-12) caused a dramatic reduction in hemolytic activity. Two analogue peptides (analogue I and III) showed more potent antifungal and lower hemolytic activity than the original peptide. To study the antifungal mechanism of these peptides, fluorescence activated flow cytometry and confocal laser scanning microscopy were performed with the most powerful antifungal analogue I peptide designed in the present study. As determined by propidium iodide staining, fungal cells treated with analogue I or melittin showed higher fluorescence intensity than those treated with the weak antifungal peptide, cecropin A. By confocal microscopy the analogue I was detected in the intracellular region as well as the in cell membrane. These facts suggested that the antifungal function of this novel peptide analogue acts by pore formation in the cell membrane.

Amino Acid Sequence↗
PubMed2001

Protection of bronchoalveolar macrophages by granulocyte-macrophage colony-stimulating factor against dexamethasone suppression of fungicidal activity for Aspergillus fumigatus conidia.

The objectives of this study were to: (i) see if granulocyte macrophage colony-stimulating factor (GM-CSF) could protect bronchoalveolar macrophages (BAM) against suppression by dexamethasone (DEX) and (ii) test the combined effect of GM-CSF and DEX on lymphocyte responses. Murine BAM killed Aspergillus fumigatus conidia by 33 +/- 4% (mean +/- SD) in a 2.5-h assay, unaffected by GM-CSF treatment. Killing by BAM treated with DEX (10(-7) M) for 48 h in vitro was reduced to 13 +/- 6%; however, if GM-CSF (500 U ml(-1)) was present during DEX treatment of BAM, killing of conidia (33 +/- 2%) by BAM was preserved. By contrast, DEX suppression of lymphocyte responses to concanavalin A was maintained during co-culture with GM-CSF. In sequence treatment experiments, initial treatment of BAM with GM-CSF protected against subsequent treatment with DEX. When macrophages were pretreated with DEX, GM-CSF could reverse suppression even when added subsequently, provided DEX treatment was discontinued. These data suggest that it may be possible to suppress lymphocyte responses with DEX, yet at the same time maintain BAM defenses with GM-CSF against pulmonary infections by conidia of A. fumigatus.

Animals↗
PubMed1977

Fungicidal components of mammalian granulocytes active against Cryptococcus neoformans.

Citric acid extracts of granule-rich fractions, prepared from rabbit and guinea pig heterophils or human neutrophis, killed Cryptococcus neoformans in vitro. These extracts sere fractionated by micropreparative electrophoresis on polyacrylamide gels. In preparation of rabbit and guinea pig heterophils, cryptococcidal activity was associated predominantely with lysosomal cationic protein complex. Human neutrophils lacked strictly comparable cationic proteins but contained other components that killed C. neoformans. These components appeared to be identical to previously described proteins of the human neutrophil active against Candida parapsilosis.

Animals↗
PubMed2001

Enhanced fungicidal activity of N-chlorotaurine in nasal secretion.

The antifungal activity of N-chlorotaurine (NCT), a long-lived oxidant produced by stimulated human leucocytes, was investigated. Incubation of Aspergillus spp., Candida spp., Fusarium spp., Penicillium spp. and Alternaria spp. in 1% NCT (55 mM) for 1-4 h produced a log10 reduction in cfu of between 1 and 4. In samples of nasal secretion, killing was significantly hastened (30 min), which may be explained by the formation of monochloramine by halogenation of ammonium, which was found at a concentration of 1 mM in these samples. For these reasons, NCT is of interest as a new agent for treatment of local inflammatory mycosis, e.g. eosinophilic fungal rhinosinusitis.

Antifungal Agents↗
PubMed1991

Fungicidal activity of Candida albicans-induced murine lymphokine-activated killer cells against C. albicans hyphae in vitro.

Multiple intraperitoneal injections of inactivated Candida albicans cells resulted in the generation of cytotoxic peritoneal cells with phenotypical and functional properties similar to in vitro-generated lymphokine-activated killer (LAK) cells. Using an in vitro [3H]glucose uptake assay, C. albicans-induced LAK-like (CA-LAK) cells exhibited high levels of anti-hyphal activity, the effects being effector to target cell (E:T) ratio- and time-dependent. Maximal levels of anti-C. albicans activity (approximately 60%) were observed after 4 h and at E:T greater than or equal to 300:1. Similar patterns of anti-C. albicans activity were exerted by in vivo-activated natural killer (NK) cells, in vitro interleukin-2- (IL-2) generated LAK cells and polymorphonuclear cells. The anti-hyphal activity of CA-LAK cells was enriched by separation on a Percoll gradient, F2 and F3 fractions retaining most of the activity. Experiments using immunodepressed animals demonstrated that the in vivo lethality of the C. albicans hyphal form is significantly affected by in vitro pre-exposure to CA-LAK cells. While control mice receiving C. albicans alone had a median survival time of 2 d, mice receiving C. albicans pre-exposed to CA-LAK cells (E:T = 300:1) had a median survival time of 15 d. Overall, the susceptibility of the C. albicans hyphal form to CA-LAK cells suggests that C. albicans-induced effectors might play a significant role as a second-line defence mechanism against the C. albicans hyphal form.

Animals↗
PubMed2001

X-ray investigations of sulfur-containing fungicides. III. Intramolecular forces governing the conformation of a novel orthorhombic polymorph of benzoylmethyl phenyl sulfone, benzoylmethyl 4-chlorophenyl sulfone and benzoylphenylmethyl phenyl sulfone.

The crystal and molecular structures of three beta-ketosulfones: benzoylmethyl phenyl sulfone (I), benzoylmethyl 4-chlorophenyl sulfone (II) and benzoylphenylmethyl phenyl sulfone (III) have been investigated using X-ray analysis and quantum mechanics ab initio calculations. Compound (I) crystallizes in the monoclinic and orthorhombic crystal systems. The crystal structure of the orthorhombic polymorph has not been reported previously. At room temperature and in the presence of daylight the pale yellow orthorhombic crystals undergo transformation to the stable colourless monoclinic polymorph. Hyperconjugative sigma(S-C1) - pi(*)(C2=O3) and sigma(*)(S-C1) - pi(C2=O3) stabilization energies in benzoylmethyl phenyl sulfones are highly dependent on the central dihedral angle alpha: S-C1-C2=O3 and are largest for a gauche arrangement, as found in both crystal forms of (I). The electron density distribution in all compounds (I), (II) and (III) is significantly affected by interactions of oxygen lone pairs with non-bonding orbitals of the adjacent S-C1 and C1-C2 bonds. The latter effect is responsible for back-donation of the electron density from O atoms towards the central part of the molecule.

Journal Article↗
PubMed2002

In vivo fungicidal effect of KP-103 in a guinea pig model of interdigital tinea pedis determined by using a new method for removing the antimycotic carryover effect.

We developed a new technique for culture study that successfully recovers fungi from drug-treated skin tissues, in which tissue specimens were homogenized, dialyzed against water, digested with trypsin, and then washed with PBS, to eliminate the drug that remaining in the skin tissue specimens. With this modified culture method, we reevaluated the efficacy of KP-103, neticonazole, and lanoconazole in a guinea pig interdigital tinea pedis model. Guinea pigs with tinea pedis were topically treated with a 1% solution of KP-103 or a reference drug once a day for 10 consecutive days. Five days after the last treatment, left and right feet were subjected to culture study by the conventional and modified recovery culture methods, respectively. One hundred percent (20/20) of lanoconazole-treated feet were judged as culture-negative by the conventional culture method, but 85% (17/20) of the feet were shown to be culture-positive when the modified recovery culture method was used. On the other hand, KP-103 achieved high rates of culture-negative rates, 95% (19/20) and 85% (17/20), in both conventional and modified culture methods, respectively. Furthermore, on day-30 posttreatment, KP-103 sterilized 14 of the 20 infected feet, whereas neticonazole and lanoconazole were not effective even in reducing fungal burden. KP-103 proved to be highly effective in achieving mycological cure and preventing relapse against tinea pedis presumably because of its good bioavailability in the skin based on its low keratin-affinity, along with its potent antifungal activity.

Animals↗
PubMed1996

New mechanisms of action with fungicidal antifungals.

Morphological modifications of growth forms of dermatophyte fungi, arthroconidia and germ tubes exposed to terbinafine incorporated in the stratum corneum were studied by scanning and transmission electron microscopy. Changes observed in arthroconidial morphology included pores and erosions present in the cell wall, with layers peeling off. The cell membrane was destroyed. Dilated vacuoles and small electron-dense areas were evident in the arthroconidial cytosol. Although germination was partially arrested, inhibition of hyphal extension was seen on all body sites examined. Germ tubes were susceptible to terbinafine, with pores appearing along their length and collapsed hyphae seen following exposure to the drug. This study suggests that the outer and inner layers of the arthroconidial cell wall are the initial targets of terbinafine action, followed by alterations to the cytosol and intracellular organelles.

Adult↗
PubMed1983

The bactericidal, fungicidal and sporicidal properties of hydrogen peroxide and peracetic acid.

The antimicrobial properties of aqueous solutions of peracetic acid and hydrogen peroxide have been compared. Peracetic acid exhibited excellent antimicrobial properties, especially under acidic conditions. Reductions by a factor of 10(6) in the numbers of vegetative bacteria are obtained within 1 min at 25 degrees C using a solution containing 1.3 mmol/l of peracetic acid. Rapid activity against bacterial spores and yeasts also occurs. Hydrogen peroxide is more effective as a sporicide than as a bactericide, with sporicidal action being obtained using a solution containing 0.88 mol/l. Bactericidal action is poor but hydrogen peroxide was bacteriostatic at concentrations above 0.15 mmol/l.

Acetates↗