Initial attachment ofCandida albicans cells to buccal epithelial cells

The rapid-freezing technique was applied in association with scanning and transmission electron microscopy to observe the initial attachment (or contact) ofCandida albicans cells to exfoliated human buccal epithelial cells. Low temperature scanning electron microscopy provided detailed three-dimensional morphological features of the yeast-epithelial cell association; adhesion ofC. albicans cells to host cells was primarily owing to an interaction between fibrillar layer of the yeast cell wall and the membrane interdigitations of the epithelial cells. Such a particular interconnection between the two cells was confirmed by the freeze-substitution fixation for transmission electron microscopy. These results clearly demonstrate the outermost fibrillar cell wall layer ofC. albicans responsible for adhesion to host cells.     

A note on the experimental uptake and clearance of Candida albicans in a young captive gull (Larus sp.)

An immature gull (Larus sp.) was placed in captivity after having been kept as a pet for several weeks and allowed to roam freely. On day one of captivity, bird feces showed the presence of Candida albicans but the yeast was absent for the next 16 days. The gull was fed only yeast-free water and fish. On day 17 only, the bird was fed fish containing C. albicans which had been isolated from a wild gull. The yeast was present in all fecal samples (2–4 per day) for the next 13 days. Beginning on day 26 and irregularly thereafter the bird was fed fish containing 100–200 mg of ketoconazole. Feces continued to show the presence of C. albicans but only sporadically because the bird continued to reinfect itself, probably by contaminating the water supply via feet or feces. After protecting the water, yeast presence in feces decreased. The gull was released on day 57; feces that day were negative for C. albicans. During the experimental period the bird displayed no clinical symptoms of candidiasis. The observations indicated that one exposure to C. albicans was sufficient to establish the carrier state and that the possibility exists for shedding a potentially dangerous microorganism over a large geographical area.     

A possible function of the chilamydospores of Candida albicans

Strains ofCandida albicans produce large numbers of chlamydospores in a liquid medium composed of 1% sodium taurocholate in distilled water. Studies made of these chlamydospores revealed that they do not contain endospores or ascospores but they do contain globules which are lipoid in character. These globules are extruded when chlamydospores split in the liquid medium or under slight pressure. Evidence was not obtained which could support van der Walt's (1967, 1969) statements to the effect that chlamydospores bud, germinate or change into other types of cells. Furthermore, no morphological or cytological evidence was found to substantiate the proposed life cycle ofC. albicans as outlined by van der Walt (1969). It is suggested that a possible function of the chlamydospores ofC. albicans is that of a storage cell.     

The effect of parenteral alimentation fluid,undiluted or diluted with saline or frseh sera,on the growth of Candida albicans in vitro at 37 °C

Parenteral alimentation is often complicated by Candida albicans infection which may be fatal. This study investigated the effect of alimentation fluid (Aminosol) on C. albicans' growth in vitro. It was found that concentrated Aminosol (1400 milliosmoles) maintained C. albicans in a viable state but inhibited replication. Dilution of alimentation fluid to physiological concentrations (300 milliosmoles) with either saline or aged pooled normal sera promoted in vitro growth of C. albicans which was equivalent to that obtained in BHI broth and was slightly less than that obtained in Sabouraud's broth. The effects of fresh sera with full complement activity were also investigated. In fresh sera appropriately diluted with physiological saline, some clumping of the yeasts was observed and all formed germ tubes. Growth as defined by budding or the formation of hyphae was inhibited. When Aminosol was diluted to 300 milliosmoles with fresh sera, all yeasts were noted to be in clumps with germ tubes as well as continually growing hyphae. Growth was approximately equal to that seen in Aminosol similarly diluted with saline.     

Flocculation phenomenon of Candida albicans by lysozyme

Young colonies of Sabouraud's glucose agar room temperature culture ofCandida species from human isolation were suspended in distilled water. The suspension was mixed with a solution of lysozyme and incubated in a 37° C water bath. Within 3–5 hours, various species ofCandida cells showed flocculation to varying degrees which occurred at varying periods of onset. Among sevenCandida species,Candida albicans andCandida stellatoidea showed the strongest flocculation, earliest onset and most solution clarity than did any other species.Candida stellatoidea was indistinguishable fromCandida albicans in its degree of flocculation, and in the clarity of solution.Candida species may be arranged in the following order according to their decreasing positivity in flocculation:

1. Candida albicans
2. Candida stellatoidea
3. Candida tropicalis
4. Candida krusei
5. Candida pseudotropicalis
6. Candida parapsilosis
7. Candida guilliermondii
8. Saccharomyces species may be placed afterCandida guilliermondii.

It seems possible to separate theCandida species into 3 groups by the rate of flocculation, and clarity of solution. Group I.Candida albicans andCandida stellatoidea. Group II.Candida tropicalis, C. krusei andCandida pseudotropicalis. Group III.Candida parapsilosis andCandida guilliermondii. Saccharomyces specimens (S. cerevisiae and others) were placed after group III.     

Yeasts in Antarctic soils

The yeast flora of 126 soil samples from the Ross Dependency of Antarctica was examined and compared with that of eight samples from East Greenland. Fifty-two Antarctic samples contained yeasts, in numbers ranging from 5 to over 100,000/g; species isolated belonged to the generaDebaryomyces, Cryptococcus, Candida, Trichosporon andRhodotorula. Nearly all isolates ofCandida were obligate psychrophils; they belonged toCandida scottii, C. nivalis, C. gelida andC. frigida. Duplicate samples, taken at the same site within a few yards of one another, contained the same size and kind of yeast populations. Although not all samples which contained plants (algae, lichens or mosses) contained yeasts, almost all samples which contained yeasts contained plants. There was no correlation between yeast population and the pH of the sample, nor between yeast populations and the presence of vertebrate animals. The samples from East Greenland, which were from an area sufficiently warm and moist to support growth of higher plants, all contained yeasts, in numbers from 200 to 56,000/g. Species isolated were similar to those from Antarctic material.     

Epidemiology and Antifungal Susceptibilities of Yeasts Causing Vulvovaginitis in a Teaching Hospital

Vulvovaginal candidiasis is one of the most common mycosis. However, the information about antifungal susceptibilities of the yeasts causing this infection is scant. We studied 121 yeasts isolated from 118 patients with vulvovaginal candidiasis. The isolates were identified by phenotypic and molecular methods, including four phenotypic methods described to differentiate Candida albicans from C. dubliniensis. Antifungal susceptibility testing was performed according to CLSI documents M27A3 and M27S4 using the drugs available as treatment option in the hospital. Diabetes, any antibacterial and amoxicillin treatment were statistically linked with vulvovaginal candidiasis, while oral contraceptives were not considered a risk factor. Previous azole-based over-the-counter antifungal treatment was statistically associated with non-C.albicans yeasts infections. The most common isolated yeast species was C. albicans (85.2 %) followed by C. glabrata (5 %), Saccharomyces cerevisiae (3.3 %), and C. dubliniensis (2.5 %). Fluconazole- and itraconazole-reduced susceptibility was observed in ten and in only one C. albicans strains, respectively. All the C. glabrata isolates showed low fluconazole MICs. Clotrimazole showed excellent potency against all but seven isolates (three C. glabrata, two S. cerevisiae, one C. albicans and one Picchia anomala). Any of the strains showed nystatin reduced susceptibility. On the other hand, terbinafine was the less potent drug. Antifungal resistance is still a rare phenomenon supporting the use of azole antifungals as empirical treatment of vulvovaginal candidiasis.     

Stability and zymogenic nature of chitin synthase fromCandida albicans

Chitin synthase preparations from both yeast and mycelialCandida albicans were chiefly in a zymogenic form, activatable by trypsin treatment. This was especially marked for preparations that had been solubilized with digitonin treatment. Endogenous activation of chitin synthase zymogen was observed over many days in preparations stored in glycerol (33%, wt/v) at?12°C and over many hours in preparations stored at 30°C. Gel chromatography of enzyme preparations suggested that zymogen was preferentially retarded on the columm matrices in comparison with active enzyme.     

Interactions ofCandida albicans with bacteria and salivary molecules in oral biofilms

The yeastCandida albicans coaggregates with a variety of streptococcal species, an interaction that may promote oral colonization by yeast cells.C. albicans andCandida tropicalis are the yeasts most frequently isolated from the human oral cavity and our data demonstrate that both these species bind toStreptococcus gordonii NCTC 7869 while two otherCandida species (Candida krusei andCandida kefyr) do not. Adherence ofC. albicans was greatest when the yeast had been grown at 30° C to mid-exponential growth phase. For 21 strains ofC. albicans there was a positive correlation between the ability to adhere toS. gordonii and adherence to experimental salivary pellicle. Whole saliva either stimulated or slightly inhibited adherence ofC. albicans toS. gordonii depending on the streptococcal growth conditions. The results suggest that the major salivary adhesins and coaggregation adhesins ofC. albicans are co-expressed.     

Antimicrobial agents

The effect of 2-aminotridecane and its addition salts with different substituted phenols on growth ofCandida albicans was studied and the fungistatic and fungicidal activity of these substances was compared. The addition 2-aminotridecane salts with 2,4,5-trichlorophenol and with 2-chloro-4-introphenol were found to be the most active in all three tests. The activity of the other addition salts tested differed little from that of actual 2-aminotridecane.     

Interaction between the antimicrobial peptide Aurein 1.2 dimer and mannans

We have previously described the structure and the ability of a dimeric analog of the antimicrobial peptide Aurein 1.2 to aggregate Candida albicans. In this study, circular dichroism and fluorescence spectroscopy data showed that this aggregation is related to the interaction between the peptide and mannans, the main component of yeast cell wall. In this context, we propose a model in which dimers interact with the polysaccharide leading to cells aggregation.     

Counterimmunoelectrophoresis as a routine mycoserological procedure

Counterimmunoelectrophoresis (CIE) has been compared in a diagnostic laboratory with agar gel double diffusion (DD) as a routine procedure for detection of antibodies to pathogenic and allergenic fungi and actinomycetes. It was shown to be of particular value in detecting antibodies to Aspergillus fumigatus. Thus 72 of 106 sera in which precipitins were detected were positive by CIE alone. Some sera were positive only by CIE to antigens prepared from Histoplasma capsulatum, Allescheria boydii, Candida albicans and C. parapsilosis.     

The antibacterial agent,moxifloxacin inhibits virulence factors of <Emphasis Type="Italic">Candida albicans</Emphasis> through multitargeting

Fluoroquinolines are broad spectrum fourth generation antibiotics. Some of the Fluoroquinolines exhibit antifungal activity. We are reporting the potential mechanism of action of a fluoroquinoline antibiotic, moxifloxacin on the growth, morphogenesis and biofilm formation of the human pathogen Candida albicans. Moxifloxacin was found to be Candidacidal in nature. Moxifloxacin seems to inhibit the yeast to Hyphal morphogenesis by affecting signaling pathways. It arrested the cell cycle of C. albicans at S phase. Docking of moxifloxacin with predicted structure of C. albicans DNA Topoisomerase II suggests that moxifloxacin may bind and inhibit the activity of DNA Topoisomerase II in C. albicans. Moxifloxacin could be used as a dual purpose antibiotic for treating mixed infections caused by bacteria as well as C. albicans. In addition chances of developing moxifloxacin resistance in C. albicans are less considering the fact that moxifloxacin may target multiple steps in yeast to hyphal transition in C. albicans.     

Neutral proteinase activity ofCandida albicans

Neutral proteinase activity (pH optimum 6–7.5) was demonstrated in cell extracts of the yeast form ofCandida albicans H-317. Proteolytic activity which required activation by treatment with sodium dodecyl sulfate was measured by a colorimetric assay for Azocoll hydrolysis. The activity was inhibited by antipain, chymostatin, phenylmethylsulfonyl fluoride, andp-chloromercuribenzoate, but was not affected by ethylenediaminetetraacetate, leupeptin, or pepstatin A. These results give the first evidence of a neutral proteinase inC. albicans.     

Isolation of Candida albicans and halophilic Vibrio spp. from aquatic birds in Connecticut and Florida

Halophilic vibrios were recovered from feces of six types of aquatic birds (gulls, pelicans, Canada geese, swans, egrets, cormorants) from Connecticut and/or Florida shorelines. Candida albicans was isolated from gulls and Canada geese in Connecticut and from gulls and cormorants in Florida.     

Isolation of Candida albicans and halophilic Vibrio spp. from aquatic birds in Connecticut and Florida.

Halophilic vibrios were recovered from feces of six types of aquatic birds (gulls, pelicans, Canada geese, swans, egrets, cormorants) from Connecticut and/or Florida shorelines. Candida albicans was isolated from gulls and Canada geese in Connecticut and from gulls and cormorants in Florida.     

Taxonomy and distribution of Chaptalia dentata and C. Albicans (Asteraceae: Mutisieae)

Chaptalia dentata (L.) Cass. andC. albicans (Sw.) Vent. ex Steudel incorrectly have been recognized as conspecific in recent treatments. Although they are vegetatively similar, they differ in features of the flowers and fruits—especially the mature achenes. Both species occur in the Bahamas and the Greater Antilles of the West Indies:Chaptalia dentata is endemic to that area, absent only from Jamaica;C. albicans is more widespread, as it occurs in Jamaica as well as in scattered localities on the American mainland—southern Florida, various localities in Belize, Honduras, and Guatemala, and the Mexican states of Veracruz, San Luis Potosí, Chiapas, and Yucatán.     

Forest and laboratory evaluations of hybridizedApanteles melanoscelus [Hym.: Braconidae], a parasitoid ofPorthetria dispar [Lep.: Lymantriidae]

Hybrids ofApanteles melanoscelus (Ratzeburg) were produced from colonies originating from France, Yugoslavia, and Connecticut. All strains, as well as freshly collected “wild” Connecticut parasitoids of the same species were evaluated in the laboratory for developmental rate, host attack rate, and sex ratios. Development was significantly slower in all the laboratory strains compared to the progeny of forest collected Connecticut females. Progeny production was greater (almost 2X) for the “wild” females and the French-Yugoslavian-Connecticut hybrid than for the laboratory Connecticut strain. The proportion of females collected from the “wild” (Connecticut) strain was higher than that observed in any laboratory strain. A field test was conducted using the triple hybrid in 3 release plots with ca. 6000A. melanoscelus cocoons released per plot in central Connecticut, U.S.A. Weekly collections of gypsy moth larvae showed that the % parasitism was significantly higher in release plots than in the 3 check plots. These results suggest the value of inundative releases ofA. melanoscelus for reduction of sparse gypsy moth populations, but they did not show that hybridization of these strains produced a more effective parasitoid under forest conditions.