The biosorption of chromium (VI) on eighteen different natural biosorbents: Natural sediment, chitosan,
chitin, Aspergillus flavus I-V, Aspergillus fumigatus I-ll, Helmintosporium sp, Cladosporium sp, Mucor rouxii mutant, M. rouxii IM-80, Mucor sp-I and 2, Candida albicans and Cryptococcus neoformans was studied in this work. It was found that the biomass of C. neoformans, natural sediment, Helmintosporium sp and chitosan was more efficient to remove chromium (VI) (determined spectrophotometrically at 540 nm
using diphenylcarbazide as the complexing agent) achieving the. following percentage of removals: 98%,
98% and 63%, respectively. The highest adsorption was obtained with C. neoformans and Helmintosporium
sp at pH 2.0 and 4.0 + 0.2, respectively, at 28∘C after 24 hours of incubation, with 0.2 mg/L of cellular
The performances of nine biosorbents derived from dead fungal biomass were investigated for their ability to remove Reactive Black 5 from aqueous solution. The biosorption data for removal of Reactive Black 5 were readily modeled using the Langmuir adsorption isotherm. Kinetic analysis based on both pseudo-second-order and Weber-Morris models indicated intraparticle diffusion was the rate limiting step for biosorption of Reactive Black 5 on to the biosorbents. Sorption capacities of the biosorbents were not correlated with the initial biosorption rates. Sensitivity analysis of the factors affecting biosorption examined by an artificial neural network model showed that pH was the most important parameter, explaining 22%, followed by nitrogen content of biosorbents (16%), initial dye concentration (15%) and carbon content of biosorbents (10%). The biosorption capacities were not proportional to surface areas of the sorbents, but were instead influenced by their chemical element composition. The main functional groups contributing to dye sorption were amine, carboxylic, and alcohol moieties. The data further suggest that differences in carbon and nitrogen contents of biosorbents may be used as a selection index for identifying effective biosorbents from dead fungal biomass.
The increasing incidence of invasive fungal infections (IFI) in immunocompromised patients emphasizes the need to improve diagnostic tools. We established a DNA microarray to detect and identify DNA from 14 fungal pathogens (Aspergillus fumigatus, Aspergillus flavus, Aspergillus terreus, Candida albicans, Candida dubliniensis, Candida glabrata, Candida lusitaniae, Candida tropicalis, Fusarium oxysporum, Fusarium solani, Mucor racemosus, Rhizopus microsporus, Scedosporium prolificans, and Trichosporon asahii) in blood, bronchoalveolar lavage, and tissue samples from high-risk patients. The assay combines multiplex PCR and consecutive DNA microarray hybridization. PCR primers and capture probes were derived from unique sequences of the 18S, 5.8S, and internal transcribed spacer 1 regions of the fungal rRNA genes. Hybridization with genomic DNA of fungal species resulted in species-specific hybridization patterns. By testing clinical samples from 46 neutropenic patients with proven, probable, or possible IFI or without IFI, we detected A. flavus, A. fumigatus, C. albicans, C. dubliniensis, C. glabrata, F. oxysporum, F. solani, R. microsporus, S. prolificans, and T. asahii. For 22 of 22 patients (5 without IFI and 17 with possible IFI), negative diagnostic results corresponded with negative microarray data. For 11 patients with proven (n = 4), probable (n = 2), and possible IFI (n = 5), data for results positive by microarray were validated by other diagnostic findings. For 11 of 11 patients with possible IFI, the microarray results provided additional information. For two patients with proven and probable invasive aspergillosis, respectively, microarray results were negative. The assay detected genomic DNA from 14 fungal pathogens from the clinical samples, pointing to a high significance for improving the diagnosis of IFI.
Biosorption of Cd(II) ions from aqueous solutions by native and dried Oscillatoria sp. Cyanobacterium biomass was investigated in the batch mode. The Oscillatoria sp. was prepared from Molecular and Cell Laboratory of University of Mazandaran and grown in BG-11 medium. A comparison of Cd(II) adsorption properties of dried with native Oscillatoria sp. biomass was made, the dried one showed a higher biosorption capacity and faster kinetic. The influence of solution pH, contact time, biomass concentration, initial metal ion concentration, and presence of coions using dried Oscillatoria sp. biomass as well as pretreatment on the biosorption capacity of the biomass were studied. Various pretreatments of Oscillatoria sp. increased biosorption of Cd(II) at pH 7 in comparison with native biomass. However, heating at 100°C in a water bath showed significant improvement in Cd(II) biosorption capacity. The experimental biosorption data was well fitted to the Freundlich model compared to the Langmuir model, and the amount of Cd(II) removed from solution increased with increasing Cd(II) concentration. In addition, the dried biomass was investigated for Cd(II) removal from the simulated real sample containing about 14 mg/l Cd(II) at pH 7, under the same experimental condition.
A high-d-xylulose mixture (d-xylose-d-xylulose = 33:67) was prepared from the cold ethanol extract of preisomerized d-xylose solution (d-xylose-d-xylulose = 77:23). Fusarium oxysporum f. sp. lini and Aspergillus niger were demonstrated to preferentially utilize d-xylose in the mixture of d-xylose and d-xylulose. Chromatographically pure d-xylulose was thus obtained in 90% yield. A high-d-xylulose mixture was also incubated with Rhodotorula toruloides, Klebsiella pneumoniae, Candida utilis, or Mucor rouxii.d-Xylose and d-xylulose were simultaneously consumed. When borate was added to the mixture, a d-xylulose-borate complex was formed, and it could be used to protect d-xylulose from being utilized.
The germination of fungal spores into hyphae was inhibited by concentrations of phenethyl alcohol (PEA) from 0.05 to 0.3%. Spores of Mucor formed budding spherical cells instead of filaments. These cells were abundant in cultures of Mucor rouxii at 0.22% PEA, provided that the carbon source was a hexose at 2 to 5%. Morphology was filamentous with xylose, maltose, sucrose, or a mixture of amino acids. Removal of PEA resulted in the conversion of yeast-like cells into hyphae. PEA did not inhibit biosynthesis of cytochromes or oxygen uptake, but it stimulated CO2 and ethyl alcohol production. PEA had no effect on the rate of oxygen uptake, but it inhibited the oxidative-phosphorylation activity of mitochondria. These results suggested that growth inhibition by PEA could result from uncoupling of oxidative phosphorylation and that, in Mucor, yeast-like morphology and fermentation were linked.
Rapid detection and differentiation of Aspergillus and Mucorales species in fungal rhinosinusitis diagnosis are desirable, since the clinical management and prognosis associated with the two taxa are fundamentally different. We describe an assay based on a combination of broad-range PCR amplification and reverse line blot hybridization (PCR/RLB) to detect and differentiate the pathogens causing fungal rhinosinusitis, which include five Aspergillus species (A. fumigatus, A. flavus, A. niger, A. terreus, and A. nidulans) and seven Mucorales species (Mucor heimalis, Mucor racemosus, Mucor cercinelloidea, Rhizopus arrhizus, Rhizopus microsporus, Rhizomucor pusillus, and Absidia corymbifera). The assay was validated with 98 well-characterized clinical isolates and 41 clinical tissue specimens. PCR/RLB showed high sensitivity and specificity, with 100% correct identifications of 98 clinical isolates and no cross-hybridization between the species-specific probes. Results for five control isolates, Candida albicans, Fusarium solani, Scedosporium apiospermum, Penicillium marneffei, and Exophiala verrucosa, were negative as judged by PCR/RLB. The analytical sensitivity of PCR/RLB was found to be 1.8 × 10−3 ng/μl by 10-fold serial dilution of Aspergillus genomic DNA. The assay identified 35 of 41 (85.4%) clinical specimens, exhibiting a higher sensitivity than fungal culture (22 of 41; 53.7%) and direct sequencing (18 of 41; 43.9%). PCR/RLB similarly showed high specificity, with correct identification 16 of 18 specimens detected by internal transcribed spacer (ITS) sequencing and 16 of 22 detected by fungal culture, but it also has the additional advantage of being able to detect mixed infection in a single clinical specimen. The PCR/RLB assay thus provides a rapid and reliable option for laboratory diagnosis of fungal rhinosinusitis.
We developed a PCR-based assay to differentiate medically important species of Aspergillus from one another and from other opportunistic molds and yeasts by employing universal, fungus-specific primers and DNA probes in an enzyme immunoassay format (PCR-EIA). Oligonucleotide probes, directed to the internal transcribed spacer 2 region of ribosomal DNA from Aspergillus flavus, Aspergillus fumigatus, Aspergillus nidulans, Aspergillus niger, Aspergillus terreus, Aspergillus ustus, and Aspergillus versicolor, differentiated 41 isolates (3 to 9 each of the respective species; P < 0.001) in a PCR-EIA detection matrix and gave no false-positive reactions with 33 species of Acremonium, Exophiala, Candida, Fusarium, Mucor, Paecilomyces, Penicillium, Rhizopus, Scedosporium, Sporothrix, or other aspergilli tested. A single DNA probe to detect all seven of the most medically important Aspergillus species (A. flavus, A. fumigatus, A. nidulans, A. niger, A. terreus, A. ustus, and A. versicolor) was also designed. Identification of Aspergillus species was accomplished within a single day by the PCR-EIA, and as little as 0.5 pg of fungal DNA could be detected by this system. In addition, fungal DNA extracted from tissues of experimentally infected rabbits was successfully amplified and identified using the PCR-EIA system. This method is simple, rapid, and sensitive for the identification of medically important Aspergillus species and for their differentiation from other opportunistic fungi.
Bartnicki-Garcia, S. (Rutgers, the State University, New Brunswick, N. J.), and Walter J. Nickerson. Thiamine and nicotinic acid: Anaerobic growth factors for Mucor rouxii. J. Bacteriol. 82:142–148. 1961.—Mucor rouxii requires preformed thiamine and nicotinic acid for anaerobic growth. Such requirements are not manifested during aerobic incubation. Aerobically, the fungus was shown to be able to synthesize both vitamins.
The yeastlike form and the filamentous form of anaerobically grown M. rouxii exhibit the same vitamin requirements.
Thiamine can be substituted by its thiazole moiety. Under certain conditions, nicotinic acid was partly substituted by tryptophan, kynurenine, 3-hydroxykynurenine, and 3-hydroxyanthranilic acid.
Anaerobically. the fungus (thiamine requiring) was about ten times more susceptible to pyrithiamine antagonism than the same organism grown aerobically (thiamine independent).
Mucor rouxii CFR-G15, a locally isolated phycomycetous fungus, on cultivation at room temperature produced more than 30% (w/w) lipid in their dry cell weight, in which 14.2% accounted to be GLA content of the total fatty acids. It was observed that when incubation temperature lowered at 14°C, GLA content of the mycelium increased significantly (P<0.05) from 14.2% to 21.97%. In order to optimize the cultural conditions for high biomass and lipid production with high GLA content, the fungus was grown in association of two different temperatures and supply of additional glucose in culture medium. Maximum lipid and GLA were obtained 23.56 and 19.5% respectively, when the culture was grown at 28°C for four days and followed by addition of glucose (5%), and lowered the incubation temperature to 14°C for another four days. The presence of GLA in the oil obtained from M. rouxii CFR-G15 was confirmed by the gas chromatography-mass spectrometry. Gamma linolenic acid (GLA, n-6) is gaining importance in pharmaceutical and nutraceutical industries because of clinical evidence demonstrated that it has various beneficial effects in human health. In this paper temperature played a major role in enhancing the GLA content which has been described.
Biomass; Gamma linolenic acid; Microbial lipids; Mucor rouxii; Polyunsaturated fatty acids
Candida and Aspergillus spp., as well as other filamentous molds, have increasingly been reported as the causes of severe invasive fungal infections. We evaluated the new echinocandin aminocandin (AMN) for its antifungal activities against a range of fungal pathogens by determination of the MICs for the organisms. The MICs of the comparator drugs amphotericin B, caspofungin, micafungin, and voriconazole were also determined. The MICs of AMN for 25 strains each of non-Candida albicans Candida spp. (including Candida parapsilosis, Candida krusei, Candida guilliermondii, and Candida tropicalis), Aspergillus fumigatus, Scedosporium spp., Fusarium spp., and zygomycetes (including Absidia, Mucor, and Rhizopus spp.) were determined by using the Clinical and Laboratory Standards Institute M27-A2 and M38-A methodologies for yeasts and filamentous molds, respectively. The MIC ranges of AMN for all yeasts were similar (0.03 to 4.0 μg/ml), while the MIC ranges of AMN for filamentous fungi were species specific. AMN demonstrated potent antifungal activity against A. fumigatus, limited activity against Scedosporium spp., and no activity against zygomycetes or Fusarium spp. Our data showed that AMN demonstrated potent antifungal activities against all of the yeasts and Aspergillus isolates tested, suggesting that AMN could be an important addition to our arsenal of antifungals for the treatment of invasive fungal disease.
Removal of heavy metals (Pb2+, Zn2+) from aqueous solution by dried biomass of Spirulina sp. was investigated. Spirulina rapidly adsorbed appreciable amount of lead and zinc from the aqueous solutions within 15 min of initial contact with the metal solution and exhibited high sequestration of lead and zinc at low equilibrium concentrations. The specific adsorption of both Pb2+ and Zn2+ increased at low concentration and decreased when biomass concentration exceeded 0.1 g l−1. The binding of lead followed Freundlich model of kinetics where as zinc supported Langmuir isotherm for adsorption with their r2 values of 0.9659 and 0.8723 respectively. The adsorption was strongly pH dependent as the maximum lead biosorption occurred at pH 4 and 10 whereas Zn2+ adsorption was at pH 8 and 10.
Biosorption; Spirulina sp.; Lead; Zinc
The antifungal activities of equimolar quantities of three azole compounds, Bay n 7133 [1-(4-chlorophenoxy)-3,3-dimethyl-2-(1,2,4-triazole-1-yl)methylbutan-2-O1], Bay 1 19139 [1-(4-chlorophenoxy)-1-(1-imidazolyl)-3,3-dimethyl-2-butanol hydrochloride], and ketoconazole, were compared by testing the susceptibility in vitro of 10 clinical isolates each of Candida albicans, Candida parapsilosis, Torulopsis glabrata, Cryptococcus neoformans, Aspergillus fumigatus, Aspergillus niger, Aspergillus flavus, Rhizopus spp., Mucor spp., and Coccidioides immitis. Molecule for molecule, ketoconazole was consistently the most active drug. All three azoles were primarily fungistatic, although they were fungicidal at clinically relevant concentrations against some strains of A. niger.
Beef luncheon meat is one of the most popular meals in several countries in the world including Egypt. Thirty one fungal species and 3 species varieties were recovered from 30 samples of beef luncheon meat collected from different supermarkets in Qena. Alternaria, Aspergillus, Emericella, Mucor, Mycosphaerella, Penicillium and Rhizopus were the most common genera on the two types of media. From the above genera, the most prevalent species were Alternaria alternate, Aspergillus flavus, A. fumigatus, A. niger, A. terreus, Emericella nidulans, Mucor racemosus, Mycosphaerella tassiana, Penicillium chrysogenum and Rhizopus stolonifer. Screening of fungi for their abilities to produce lipase enzyme showed that, ten isolates represented 32.26% of total isolates appeared high lipase production, while sixteen isolates (51.61%) were moderate and 5 isolates (16.13%) were low producers. Aspergillus niger, Fusarium oxysporum and Nectria haematococca produced the highest amount of lipase enzyme, so these fungi were used in further studies. The incorporation of five food preservatives (Disodium phosphate, sodium benzoate, citric acid, potassium sorbate and sodium citrate) individually in the culture medium of lipase production exhibited an inhibitive effect on the mycelial growth and enzyme production by Aspergillus niger, Fusarium oxysporum and Nectria haematococca.
Beef luncheon fungi; Food preservatives; Lipase
In anaerobic cultures of Mucor rouxii, morphogenesis was strongly dependent on hexose concentration as well as pCO2. At low levels of hexose or CO2, or both, hyphal development occurred; at high levels, the fungus developed as yeast cells. Other dimorphic strains of Mucor responded similarly to hexose and CO2 but differred in their relative sensitivity to these agents. Glucose was the most effective hexose in eliciting yeast development of M. rouxii; fructose and mannose were next; and galactose was last. The fungus may be grown into shapes covering its entire dimorphic spectrum simply by manipulating the hexose concentration of the medium. Thus, at 0.01% glucose, hyphae were exceedingly long and narrow; at higher sugar concentrations, the hyphae became progressively shorter and wider; finally, at about 8% glucose, almost all cells and their progeny were isodiametric (spherical budding cells). Such yeast development occurred without a manifested requirement for exogenous CO2. The stimulation of yeast development by hexose is not an artifact due to increased production of metabolic CO2 (hyphae or yeast cells released metabolic CO2 at similar rates). Presumably, the effect was caused by some other hexose catabolite which interfered with hyphal morphogenesis (apical growth); deprived of its polarity, the fungus grew into spherical yeastlike shapes. Although 10% glucose inhibited the development of hyphae from germinating spores, it did not prevent the elongation of preformed hyphae. This suggests that hexose inhibits hyphal morphogenesis not by blocking the operation of the enzyme complex responsible for apical growth but by preventing its initiation; such inhibition may be regarded as a repression of hyphal morphogenesis.
Bartnicki-Garcia, S. (Rutgers, The State University, New Brunswick, N.J.) and Walter J. Nickerson. Nutrition, growth, and morphogenesis of Mucor rouxii. J. Bacteriol. 84:841–858. 1962.—Mucor rouxii was grown under three different atmospheres of incubation: air, N2, and CO2 in parallel cultures. The atmosphere of incubation markedly affected nutritional requirements, growth, and morphogenesis. Absence of oxygen greatly reduced growth and increased the nutritional demands of the fungus. Presence of a high tension of CO2 resulted in a change from filamentous to yeastlike morphogenesis. Aerobically, a large variety of carbon sources was utilized; anaerobically, only hexoses served to meet requirements for carbon and energy. Aerobically, various amino acids supported abundant growth; anaerobically, they were poorly utilized. Ammonium and nitrate ions were better sources of nitrogen for anaerobic growth. In general, incubation under either air or N2 resulted in development of coenocytic filamentous mycelium, whereas incubation under CO2 resulted in development of budding yeastlike cells. Variations in temperature and time of incubation, inoculum size, type and concentration of carbon source, type of nitrogen source, and presence of various substances with known action on fungal morphogenesis altered growth in many cases, but did not significantly affect the patterns of vegetative morphogenesis conditioned by each atmosphere of incubation. However, vegetative morphogenesis was strongly affected by addition of certain chelating agents. Yeastlike development of M. rouxii was prevented by ethylene-diaminetetraacetic acid (EDTA) in concentrations which were also partially inhibitory for growth; under these conditions, development was filamentous. Chemically related chelating agents were similarly active. The growth-inhibitory and morphogenetic effects of EDTA were reversed by transition-group metal ions. Yeastlike development of M. subtilissimus, which does not require CO2 for its induction, was also inhibited by EDTA.
It is estimated that about 10% of the population have IgE antibodies to common inhalant molds. Exposure to fungal allergens could be linked to the presence and persistence of asthma, rhinitis and atopic dermatitis. Mold sensitization is a risk factor for development and deterioration of upper airway allergy, especially chronic rhinosinusitis. We addressed the incidence of mold allergy measured as specific IgE to molds and skin prick tests in chronic sinusitis patients. We assessed prevalence of allergic reactions to mould among surgery treated chronic sinusitis patients.
A group of 28 chronic sinusitis patients after surgery were included into the study. Routine medical examination, skin prick tests with common inhaled allergens and extended mold panel (Alternaria alternate, Cladosporium herbarium, Aspergilus fumigatus, Candida albicans, Mucor mucedo, Botrytis cinerea, Rhisopus nigricans, Penicilliumi notatum, Fusarum moniliforme Pullularia pullulans (Allergopharma, Germany), tIgE, asIgE measurement were performed (Phadia, Sweden). All investigated patients were consulted by laryngologist and mycological examination was performed.
We found that sensitization to at least one allergen was present in 43.8(14/32) of sinusitis patients. The most prevalent was sensitization to house dust mite Dermatophagoides pt., found in 21.8 % (7/32) patients. Positive results of skin prick tests with Candida albicans we observed in 18.8% (6/32), with Alternaria alternate in 15,6% (5/32), Cladosporium herbarium in 6,3% (2/32), Aspergilus fumigatus in 3,13 % (1/32). None of investigated patients presented sensitization to other mold allergens. Microbiological methods demonstrated fungal infection only in 2 patients.
Almost half of chronic sinusitis patients presented sensitization to at least one allergen. Fungal allergy is relatively rare in chronic sinusitis patients.
The present study aims to evaluate the competitive biosorption of lead, cadmium, copper, and arsenic ions by using native algae. A series of experiments were carried out in a batch reactor to obtain equilibrium data for adsorption of single, binary, ternary, and quaternary metal solutions. The biosorption of these metals is based on ion exchange mechanism accompanied by the release of light metals such as calcium, magnesium, and sodium. Experimental parameters such as pH, initial metal concentrations, and temperature were studied. The optimum pH found for removal were 5 for Cd2+ and As3+ and 3 and 4 for Pb2+ and Cu2+, respectively. Fourier transformation infrared spectroscopy analysis was used to find the effects of functional groups of algae in biosorption process. The results showed that Pb2+ made a greater change in the functional groups of algal biomass due to high affinity to this metal. An ion exchange model was found suitable for describing the biosorption process. The affinity constants sequence calculated for single system was KPb > KCu > KCd > KAs; these values reduced in binary, ternary, and quaternary systems. In addition, the experimental data showed that the biosorption of the four metals fitted well the pseudo-second-order kinetics model.
Competitive biosorption; Algae; Ion exchange model; Affinity constant; Kinetics
In recent years, biosorption process has become an economic and eco-friendly alternative treatment technology in the water and wastewater industry. In this light, a number of biosorbents were developed and are successfully employed for treating various pollutants including metals, dyes, phenols, fluoride, and pharmaceuticals in solutions (aqueous/oil). However, still there are few technical barriers in the biosorption process that impede its commercialization and thus to overcome these problems there has been a steadily growing interest in this research field. This resulted in large numbers of publications and patents each year. This review reports the state of the art in biosorption research. In this review, we provide a compendium of know-how in laboratory methodology, mathematical modeling of equilibrium and kinetics, identification of the biosorption mechanism. Various mathematical models of biosorption were discussed: the process in packed-bed column arrangement, as well as by suspended biomass. Particular attention was paid to patents in biosorption and pilot-scale systems. In addition, we provided future aspects in biosorption research.
Biosorption; Research methodology; Kinetics; Equilibrium; Process solutions; Application in practice
The aim of this study was to find a reliable method for the detection and identification of fungi in fungus balls of the maxillary sinus and to evaluate the spectrum of fungi in these samples. One hundred twelve samples were obtained from patients with histologically proven fungal infections; 81 samples were paraffin-embedded tissue sections of the maxillary sinus. In 31 cases, sinus contents without paraffin embedding were sent for investigation. PCR amplification with universal fungal primers for 28S ribosomal DNA and amplicon identification by hybridization with species-specific probes for Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger, Aspergillus terreus, Aspergillus glaucus, Pseudallescheria boydii, Candida albicans, and Candida glabrata were performed for all samples. Furthermore, PCR products were sequenced. Fresh samples were also cultivated. Fungal DNA was detected in all of the fresh samples but only in 71 paraffin-embedded tissue samples (87.7%). Sequence analysis was the most sensitive technique, as results could be obtained for 28 (90.3%) fresh samples by this method in comparison to 24 (77.4%) samples by hybridization and 16 (51.6%) samples by culture. However, sequence analysis delivered a result for only 36 (50.7%) of the paraffin-embedded specimens. Hybridization showed reliable results for A. fumigatus, which proved to be the most common agent in fungus balls of the maxillary sinus. Other Aspergillus species and other genera were rarely found.
In the present study, effort has been made to find the antimicrobial activity of haemolymph collected from freshwater crab, Paratelphusa hydrodromous. The haemolymph collected was tested for antimicrobial assay by disc diffusion method against clinical pathogens. Five bacterial species, namely, Escherichia coli, Klebsiella pneumonia, Proteus mirabilis, Pseudomonas aeruginosa, Staphylococcus aureus, and five fungal strains, namely and Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Rhizopus sp., and Mucor sp., were selected for the study. The result shows a strong response of haemolymph against the clinical pathogens which confirms the immune mechanism of the freshwater crab.
Seventy-three fungal species belonging to forty-three genera were isolated from 40 samples of Saccharrum officinarum (collected from Naage-Hamadi canal in Qena Governorate, Egypt). Aspergillus, Trichoderma, Mucor and Pythium were the most common genera on the two isolation media. The dominant species of Aspergillus were A. niger, A. flavus, A. ustus, A. terreus and A. wentii. Some species were dominant on 40 g/l sucrose such as Aspergillus niger, A. flavus, Emericella nidulans, Trichoderma viride, Torula herbarum and Mamaria echinoeotryoides, while the dominant species on 10 g/l glucose were Mucor circinelloides, Aspergillus niger, Torula herbarum and Trichoderma viride. Mycotoxins including aflatoxins B1, B2, G1 and G2, zearalenone and diacetoxyscirpenol were detected in the examined samples of Saccharrum officinarum. The mycelial growth of A. flavus, A. niger, Fusarium moniliforme and Torula herbarum decreased with the increase in Dimethoate concentrations, although 25 ppm was less effective than the higher levels of the insecticide (75~200 ppm). Dimethoate stimulated the activity of Go-T in A. niger, F. moniliforme and T. harbarum, while the Go-T activity was inhibited in A. flavus with the Dimethoate treatments.
Aquatic and terrestrial fungi; Mycotoxin production; Saccharrum officinarum
Platinum nanomaterial is one of the significant noble metal catalysts, and the interaction of platinum with microbe is one of the key factors in influencing the size and the distribution of the platinum nanoparticles on the microbial biomass. Some properties of Pt(IV) adsorption and reduction by resting cells of Bacillus megatherium D01 biomass have once been investigated, still the mechanism active in the platinum biosorption remains to be seen and requires further elucidating.
A further insight into the biosorption mechanism of Pt(IV) onto resting cells of Bacillus megatherium D02 biomass on a molecular level has been obtained. The image of scanning electron microscopy (SEM) of the D02 biomass challenged with Pt(IV) displayed a clear distribution of bioreduced platinum particles with sizes of nanometer scale on the biomass. The state of Pt(IV) bioreduced to elemental Pt(0) examined via X-ray photoelectron spectroscopy (XPS) suggested that the biomass reduces the Pt(IV) to Pt(II) followed by a slower reduction to Pt(0). The analysis of glucose content in the hydrolysates of D02 biomass for different time intervals using ultraviolet-visible (UV-vis) spectrophotometry indicated that certain reducing sugars occur in the hydrolyzed biomass and that the hydrolysis of polysaccharides of the biomass is a rapid process. The infrared (IR) spectrometry on D02 biomass and that challenged with Pt(IV), and on glucose and that reacted with Pt(IV) demonstrated that the interaction of the biomass with Pt(IV) seems to be through oxygenous or nitrogenous chemical functional groups on the cell wall biopolymers; that the potential binding sites for Pt species include hydroxyl of saccharides, carboxylate anion and carboxyl of amino acid residues, peptide bond, etc.; and that the free monosaccharic group bearing hemiacetalic hydroxyl from the hydrolyzed biomass behaving as an electron donor, in situ reduces the Pt(IV) to Pt(0). And moreover, the binding of the Pt(IV) to the oxygen of the carbonyl group of peptide bond caused a change in the secondary structure of proteins; i.e. a transformation, in polypeptide chains, of β-folded to α-helical form; it might be expected to be more advantageous than β-folded form to the platinum nanoparticles under shelter from gathering although the both special conformations of proteins could be much probably responsible for the stabilization of the particles.
That knowledge could serve as a guide in the researches for improving the preparation of highly dispersive supported platinum catalyst and for fabricating new advanced platinum nanostructured devices by biotechnological methods.
Inserts which carried the CUP gene from Saccharomyces cerevisiae or Mucor racemosus were used as hybridization probes to measure the methylation state and expression of the CUP gene from Mucor rouxii at different stages of growth. It was observed that the fungus contains a CUP multigene family. All the CUP genes were present in a hypermethylated DNA region in nongrowing and isodiametrically growing spores and were not transcribed at these stages. After germ tube emergence, CUP genes became demethylated and transcriptionally active. Development, demethylation, and transcription of CUP genes were blocked by the ornithine decarboxylase inhibitor 1,4-diaminobutanone. These results suggest that genes that are activated during development became demethylated in this fungus.
In immunocompromised patients suffering from invasive fungal infection, rapid identification of the fungal species is a prerequisite for selection of the most appropriate antifungal treatment. We present an assay permitting reliable identification of a wide range of clinically relevant fungal pathogens based on the high-throughput Luminex microbead hybridization technology. The internal transcribed spacer (ITS2) region, which is highly variable among genomes of individual fungal species, was used to generate oligonucleotide hybridization probes for specific identification. The spectrum of pathogenic fungi covered by the assay includes the most commonly occurring species of the genera Aspergillus and Candida and a number of important emerging fungi, such as Cryptococcus, Fusarium, Trichosporon, Mucor, Rhizopus, Penicillium, Absidia, and Acremonium. Up to three different probes are employed for the detection of each fungal species. The redundancy in the design of the assay should ensure unambiguous fungus identification even in the presence of mutations in individual target regions. The current set of hybridization oligonucleotides includes 75 species- and genus-specific probes which had been carefully tested for specificity by repeated analysis of multiple reference strains. To provide adequate sensitivity for clinical application, the assay includes amplification of the ITS2 region by a seminested PCR approach prior to hybridization of the amplicons to the probe panel using the Luminex technology. A variety of fungal pathogens were successfully identified in clinical specimens that included peripheral blood, samples from biopsies of pulmonary infiltrations, and bronchotracheal secretions derived from patients with documented invasive fungal infections. Our observations demonstrate that the Luminex-based technology presented permits rapid and reliable identification of fungal species and may therefore be instrumental in routine clinical diagnostics.