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.     

Culture of Candida in vinasse and molasses: Effect of acid and salt addition on biomass and raw protein production

Species of the genera Candida grown in vinasse and molasses were studied under the following conditions: agitation of containers, pH 4.6, culture time of 24 hours at 30°C. The greatest biomass production of C. krusei grown in vinasse was obtained with the addition of 0.1% H₃PO₄, and of C. guilliermondii and C. utilis with the addition 0.02% urea plus 0.03% H₃PO₄. Protein levels near 50% were found in C. utilis in vinasse supplemented either with molasses, with 0.05% MgSO₄, or with 0.02% urea plus 0.03% H₃PO₄.     

Early diagnosis of blood culture isolates in patients with candidemia using PNA FISH

Candidemia is associated with high mortality, especially with neutropenic and intensive care unit patients. A delay in early, effective antifungal therapy has been associated with increased mortality and hospital costs. Peptide nucleic acid fluorescent in-situ hybridization (PNA FISH) can identify Candida species within 3 hours after a positive blood culture demonstrates yeast. A Candida albicans probe and a dual C. albicans/Candida glabrata probe are available in clinical practice, and multi-Candida species probes and flow cytometry are in development. Recent data suggest that the rapid identification of Candida species with PNA FISH can provide early targeted therapy to patients and thus reduce antifungal costs and improve patient care. This review evaluates the clinical and laboratory effects of the Candida probes and their limitations, and competing technologies. Candida PNA FISH probes offer clinicians the early knowledge of the species they are treating, allowing them to appropriately tailor therapy.     

Evaluation of Antifungal Susceptibility Testing with Microdilution and Etest Methods of <Emphasis Type="Italic">Candida</Emphasis> Blood Isolates

Candida species that show an increasing number of clinical and/or microbiological resistance to several antifungals and are the most common agents of invasive fungal infections. The aim of this study was to investigate the in vitro susceptibility of Candida blood isolates to antifungal agents (amphotericin B, fluconazole, itraconazole, and voriconazole) by comparative use of the CLSI reference microdilution method and Etest. Four hundred Candida blood isolates (215 Candida albicans, 185 non-albicans Candida strains) were included in the study. The broth microdilution test was performed according to the CLSI M27 A2 document. Etest was carried out according to the manufacturer’s instructions. The MIC results obtained with reference microdilution were compared with those obtained with the Etest by using percent and categorical agreements. According to MIK₉₀ values, voriconazole was the most active and itraconazole was the least active drug in vitro against all Candida species. Other than voriconazole, statistically significant differences were found when the susceptibility of Candida albicans and non-albicans Candida spp. to amphotericin B, fluconazole, and itraconazole were compared. These antifungal agents were found to be more active to C. albicans. Among the non-albicans Candida species, the lowest MIC values were obtained for Candida parapsilosis isolates. When the standard method was compared with Etest, the total agreement was higher for C. albicans than for non-albicans species, especially for fluconazole and voriconazole. In view of the findings, it was concluded that itraconazole showed the lowest activity against all Candida species. Etest could be an alternative method in assessing the in vitro antifungal susceptibility of Candida spp., but it is more convenient to use the microdilution method for studying in vitro susceptibility of non-albicans species, in particular for those possessing high MIC values against azoles.     

An immunofluorescent technique for rapid control of the purity of yeast cultures

Summary A rapid technique for control of purity of cultures ofCandida utilis can be based on fluorescent labeling of cells using an antiserum raised in rabbits and rendered specific by absorption with cross-reacting strains. Microscopical observation under mixed ultraviolet/visible illumination permits detection of one non-fluorescent contaminant cell among 10³ fluorescent cells. Cells of all ages of allC.utilis strains tested reacted with the antiserum. Seven cross-reacting species were found among the 53 species from 15 genera of yeast tested.     

Novel lignocellulolytic ability of Candida utilis during solid-substrate cultivation on apple pomace

Lignocellulolytic enzymes from conventional and non-conventional yeasts are not commonly studied, and they have never been described for Candida utilis species. After solid-substrate cultivation of C. utilis (CCT 3469) on apple pomace, degradation of cellulose, pectin and lignin fragments was observed. Production of the main lignocellulolytic enzymes by C. utilis was investigated and high activity for pectinase (239 U ml^–1) as well as a significant manganese-dependent peroxidase (19.1 U ml^–1) activity was found. Low cellulase (3.0 U ml^–1) and xylanase (1.2 U ml^–1) activities were also observed suggesting that C. utilis may have lignocellulose degradation ability.     

Comparative spikelet morphology ofOryza schlechteri Pilger and related species ofLeersia andOryza (Poaceae)

Oryza schlechteri has only recently been rediscovered in Papua New Guinea. This species is quite distinct from otherOryza species but resembles closely related genusLeersia in its small panicle and profusely spreading habit. On the basis of spikelet morphology that has previously been used to distinguishLeersia andOryza species,O. schlechteri was compared withO. brachyantha. O. longiglumis, O. sativa, L. perrieri, L. tisseranti, andL. hexandra to clarify its generic position. Results corroborate that the presence of a sterile lemma and a striated spikelet epidermal (abaxial) surface lacking siliceous triads inO. schlechteri allies this species with otherOryza species rather than withLeersia.     

川西米亚罗亚高山暗针叶林岷江冷杉和糙皮桦空间格局及其关联性分析

基于2019年9月完成的川西米亚罗亚高山暗针叶林9.6 hm~2动态样地的调查数据,分析了主要优势种岷江冷杉(Abies fargesii var.faxoniana)与糙皮桦(Betula utilis)的径级结构,并运用O-ring统计中的成对相关函数g(r)和g₁₂(r),研究了两个优势种的空间格局及其种内、种间的关联性。结果表明：岷江冷杉与糙皮桦径级分布连续,均呈倒“J”型。岷江冷杉与糙皮桦的不同径级个体主要呈现由聚集分布向随机分布发展的趋势。岷江冷杉的小树对幼树、中树对幼树、中树对小树以及大树对中树的种内相关性在所有空间尺度上均为显著正相关(P<0.05),而相同径级糙皮桦的种内相关性则表现为由显著正相关(P<0.05)逐渐向无显著相关(P>0.05)变化。随着空间尺度的增大,岷江冷杉的大树对幼树、大树和小树由无显著相关(P>0.05)逐渐向显著正相关(P<0.05)变化,糙皮桦的大树对幼树由显著负相关(P<0.05)逐渐向无显著相关(P>0.05)变化。岷江冷杉大树对糙皮桦所有径级个体的种间相关性主要呈现由为显...     

The carriage of Candida species on the dorsal surface of the tongue: the correlation with the dental, periodontal and prosthetic status in elderly subjects

Objectives: To screen the carriage status of Candida species, especially Candida albicans and its genotype in an epidemiological survey and to investigate its correlation with the dental, periodontal and prosthetic status of healthy elderly subjects. Materials and methods: Microbiological samples were collected from the dorsum of the tongue of 366 subjects, aged 75, and cultured on CHROMagar medium. The carriage status of Candida spp. and the distribution of C. albicans genotypes by a polymerase chain reaction (PCR) method were analysed and compared with the dental, periodontal and prosthetic status of the subjects. Results: A high carriage rate (68.6%) of Candida spp. and the predominant species of C. albicans (72.1%) were found in this study. The prevalence, density and multi‐species of Candida spp. were significantly related to the presence of a dental prosthesis. In C. albicans, genotype A predominated (56.4%) and genotype D showed a higher prevalence (12.5%) than previous reports. When comparing Candida spp. carriage with the oral status, significant positive correlations were found with the presence of any dental prosthesis, missing teeth, the number of retained roots and the percentage of sites showing bleeding on probing (BOP), while significant negative correlations were found with the number of teeth present, sound and filled teeth. Conclusions: Candida carriage on the dorsum of the tongue in healthy elderly is significantly associated with the dental, periodontal and prosthetic status, especially the presence of a dental prosthesis. As the complexity of the prosthesis being worn increased, the relative risk of Candida carriage and the numbers and multi‐species of Candida increased accordingly.     

Advances in Candida detection platforms for clinical and point-of-care applications

Invasive candidiasis remains one of the most serious community and healthcare-acquired infections worldwide. Conventional Candida detection methods based on blood and plate culture are time-consuming and require at least 2–4 days to identify various Candida species. Despite considerable advances for candidiasis detection, the development of simple, compact and portable point-of-care diagnostics for rapid and precise testing that automatically performs cell lysis, nucleic acid extraction, purification and detection still remains a challenge. Here, we systematically review most prominent conventional and nonconventional techniques for the detection of various Candida species, including Candida staining, blood culture, serological testing and nucleic acid-based analysis. We also discuss the most advanced lab on a chip devices for candida detection.     

Synergy of human neutrophils with fluconazole in killing Candida species

The killing of Candida species by human neutrophils in a long-term 24-h assay and possible synergy with fluconazole (FCZ) for killing was investigated. The test medium (TM) consisted of RPMI-1640, penicillin and streptomycin (P/S), and 10% fresh autologous serum. TM alone was highly fungistatic for Candida species compared to TM without serum. When neutrophils were cocultured in TM with Candida species for 24 h the inoculum colony-forming units (CFU) were always significantly reduced (killing) by 58 to 99%. FCZ was tested over a range of 1–500 g/ml, and though almost always fungistatic itself, it synergized with neutrophils for significantly increased killing of C. albicans (isolate Sh27) (P<0.01) and C. albicans (isolate 94-20) (P<0.05). Killing of non-albicans Candida species was so efficient in the absence of FCZ that demonstration of synergy with FCZ was difficult.     

Evidence from RAPD markers in the evolution ofEchinochloa millets (Poaceae)

Echinochloa (Poaceae) includes two domesticated species,Echinochloa utilis (Japanese barnyard millet) andE. frumentacea (Indian sawa millet) and 20–30 wild species. The two millets are morphologically very variable and overlap in spikelet and inflorescence characteristics. Both species are hexaploids based on x = 9. Cytogenetic studies point to the hexaploid wild speciesE. crusgalli andE. colona as possible progenitors ofE. utilis andE. frumentacea, respectively. The tetraploidE. oryzoides is considered as a possible genome donor to wild and domesticated barnyard millet. Markers from Random Amplified Polymorphic DNA method were used to assess the proposed phylogeny and examine the genetic diversity in both domesticated and wild species. The data were analyzed numerically.Echinochloa utilis andE. frumentacea appear very distinct, but grouped withE. crusgalli andE. colona, respectively. The tetraploidE. oryzoides show strong genetic affinity to theE. utilis—E. crusgalli group. The data are in general agreement with the cytogenetic information; however, some disagreements on the interpretation of some of the cytogenetic information is raised. The variability in DNA markers observed in the domesticated species, particularlyE. frumentacea, points to the feasibility of using RAPD markers in cultivar fingerprinting and breeding programs of these millets.     

<Emphasis Type="Italic">Colletotrichum echinochloae</Emphasis>, a new species on Japanese barnyard millet (<Emphasis Type="Italic">Echinochloa utilis</Emphasis>)

Five isolates of a species of Colletotrichum were collected from Japanese barnyard millet (Echinochloa utilis) in Japan. Although the fungus had once been identi-fied as C. graminicola sensu lato, it was clearly different from C. graminicola isolated from maize (Zea mays) in its falcate and short conidia, 18.0–22.2 μm in length, cultural characteristics, and specific pathogenicity to E. utilis. Moreover, molecular phylogenetic analyses using sequences of rDNA-ITS, HMG, and SOD2 indicated a monophyly of the isolates. A new species, Colletotrichum echinochloae, is then proposed based on the morphological, pathological, and molecular characteristics.     

Systematics of the genusCandida Berkhout: Proton magnetic resonance spectra of the mannans and mannose-containing polysaccharides as an aid in classification

The proton magnetic resonance (p.m.r.) spectra of the mannans, galactomannans and mannose-containing heteropolysaccharides of a number of species ofCandida were determined, and compared with the spectra of similar polysaccharides of some species of the sporogenous generaPichia, Hansenula, Endomycopsis, Debaryomyces andSaccharomyces. Similarities among the spectra were used as an aid in classification. TheCandida species studied were placed in four groups: 1) thoseCandida species classified as asporogenous forms of perfect species, 2) those which produce mannose-containing polysaccharides having p.m.r. spectra resembling those of the mannans of known perfect species, 3) members of theCandida parapsilosis group, 4) thoseCandida species which did not ferment glucose and which were not included in one of the other groups.Issued as N.R.C. No. 10566.The authors are grateful to all those who made the work possible by supplying the cultures and materials studied. They wish also to thank Mr. M. Mazurek for the determination of the p.m.r. spectra, and Mr. N. R. Gardner and Mr. R. J. Magus for valuable technical assistance.     

Biological control of oliver scale,Parlatoria oleae (Colvée), in a deciduous fruit Orchard in California

Conclusions Data obtained during the years 1960–1966 show conclusively that the olive scale parasites,Aphytis maculicornis andCoccophagoides utilis, when well-established, are capable of fully effective control of their host on a commerciallty-grown deciduous fruit host.A. maculicornis alone, prior to the establishment ofC. utilis, failed to reduce or maintain control of scale densities. Subsequent to the colonization and establishement ofC. utilis in 1962 and its assumption of a contributing role as an agent of biological control of oliver scale, both species of parasites were able to reduce the host below economic levels within a year. Scale densities have decreased continually since 1963. Continuation of satisfactory biological control is indicated by the low densities of scales now maintained by its parasites. Judicious use of chemical treatments, both in selection and in timing of application, to control other insect and mit problems will ensure the continuing biological control of oliove scale in this deciduous orchard.     

Use of CHROMagar in the Differentiation of Common Species of <Emphasis Type="Italic">Candida</Emphasis>

CHROMagar has been reported to be useful for the rapid and accurate identification of Candida species. We tested 135 isolates of Candida species isolated from oropharyngeal candidiasis in HIV patients and found that it was useful in the presumptive identification of Candida albicans and Candida krusei. Occasional strains of C. tropicalis produced colonies with a greenish tinge making it difficult to differentiate from C. albicans.     

A real‐time PCR assay for the differentiation of Candida species

Aims: We established a real‐time PCR assay for the detection and strain identification of Candida species and demonstrated the ability to differentiate between Candida albicans the most common species, and also Candida parapsilosis, Candida glabrata, Candida tropicalis and Candida dubliniensis by LightCycler PCR and melting curve analysis. Methods and Results: The DNA isolation from cultures and serum was established using the QIAmp Tissue Kit. The sensitivity of the assay was ≥ 2 genome equivalents/assay. It was possible to differentiate all investigated Candida species by melting curve analysis, and no cross‐reaction to human DNA or Aspergillus species could be observed. Conclusions: The established real‐time PCR assay is a useful tool for the rapid identification of Candida species and a base technology for more complex PCR assays. Significance and Impact of the Study: We carried out initial steps in validation of a PCR assay for the detection and differentiation of medically relevant Candida species. The PCR was improved by generating PCR standards, additional generation of melting curves for species identification and the possibility to investigate different specimens simultaneously.     

金佛山方竹经营对扁刺栲群落物种多样性和优势种种群结构的影响

为探讨金佛山方竹经营对扁刺栲群落物种多样性和优势种种群结构的影响,该研究以金佛山的扁刺栲自然群落和金佛山方竹经营群落为对象,分析了两类群落的物种组成特征、物种多样性及优势种种群结构。结果表明：(1)两种群落内共记录维管束植物84种,隶属于40科63属,以樟科、蔷薇科、壳斗科、山茶科物种为主;扁刺栲为群落优势种,中华木荷和灰柯为次优势种,金佛山方竹为灌木层优势种,扁刺栲群落组成与亚热带其他地区的扁刺栲群落组成相似。(2)金佛山方竹经营群落的灌木层物种丰富度显著低于自然群落,草本层Shannon-Wiener指数和Pielou指数均显著低于自然群落。(3)扁刺栲和灰柯在自然群落中为稳定型种群,而在金佛山方竹经营群落中为衰退型种群,中华木荷在两类群落中均为衰退型种群。(4)自然群落中扁刺栲、中华木荷、灰柯种群的萌枝率、有萌个体率和幼苗相对优势度均高于金佛山方竹经营群落。综上认为,金佛山方竹经营对金佛山扁刺栲群落灌木层和草本层物种多样性产生了负面影响,并显著影响扁刺栲群落优势种种群更新和维持。     

Species distribution and antifungal susceptibility patterns of <Emphasis Type="Italic">Candida</Emphasis> spp. bloodstream isolates from a Brazilian tertiary care hospital

In this work, we collect data from surveys of bloodstream Candida isolates performed in Brazil from 1996 to 2004. Besides, we analyzed the species distribution of bloodstream Candida isolates together with potential risk factors for candidemia and the susceptibility profile of these isolates in patients from Hospital das Clínicas in Goiania city, Brazil. Blood samples were collected in the admission day and on every 7 days, in the intensive care unit (ICU) of a tertiary hospital. Candida isolates were identified by standard protocols that included germ tube formation, chlamydoconidia production on cornmeal agar and sugar fermentation and assimilation tests. Data of patients were recorded and analyzed according to age at the time of diagnosis, gender and presence of potential risk factors. Statistical analysis was used to determine if the time of hospital permanence increased Candida colonization in ICU patients’ blood. The antifungal susceptibility testing was performed by broth microdilution method according to document NCCLS/CLSI M27–A2. Among the 345 blood samples cultured, candidemia was recovered in 33 patients, which were isolated 51.5% of Candida non-albicans. Fungemia was associated with long-term hospitalization. Fluconazole, itraconzole, voriconazole and amphotericin B exhibited a potent activity against all isolates of Candida. Voriconazole MICs were much low for all isolates tested. This work confirms data of increase of Candida non-albicans species in bloodstream in ICU and shows that voriconazole in vitro activity was higher than those of itraconazole, fluconazole and amphotericin B.