Filamentous Yeasts Research Articles

Application of natamycin and farnesol as bioprotection agents to inhibit biofilm formation of yeasts and foodborne bacterial pathogens in apple juice processing lines

Biofilms serve as a reservoir for pathogenic and spoilage microorganisms, and their removal from different surfaces is a recurring problem in the beverage industry. This study aimed to investigate the effect of a combination of natamycin (NAT, 0.01 mmol/l) and farnesol (FAR, 0.6 mmol/l) against biofilms on ultrafiltration (UF) membranes and stainless steel (SS) surfaces using apple juice as food matrix. The co-adhesion of Rhodotorula mucilaginosa, Candida tropicalis, C. krusei and C. kefyr (mixed-yeast) with Listeria monocytogenes, Salmonella enterica or Escherichia coli O157:H7 (multi-species) in presence of NAT + FAR was evaluated for 2, 24, 48 h. In biofilms treated with NAT + FAR were observed by cell quantification and microscopy, inhibition of the filamentous yeast forms, disruption of the tri-dimensional structure and a high detachment of yeast cells. NAT + FAR affected the biofilms independently of the surfaces used and the presence (or not) of bacteria. L. monocytogenes was the most susceptible (p < 0.001) in multi-species biofilms, followed by E. coli O157:H7 on both surfaces (p < 0.001), whereas the growth of S. enterica was reduced (p < 0.05) in SS but not in UF-membranes (p > 0.05). Since the combination NAT + FAR affected the structure and viability of yeast species and foodborne pathogens in multi-species biofilms developed on UF-membranes and SS surfaces, the combination proposed could be considered a promising control agent to prevent biofilms in apple juice processing lines.

Analysis of aflatoxins and ergot alkaloids in feeds for adult equine

Mycotoxins are products resulting from fungi metabolism normally present in the environment and which can develop in food. The aim of this study was the fungi quantification, aflatoxin detection and investigation of ergot alkaloids occurrence in pelleted feed for adult equines during storage. The feed samples were collected from three rural properties with equideoculture activity in the city of Teresina, Piauí, Brazil. The results showed that was no significant difference (p&lt;0.05) for the counting of colony-forming units (CFU/g) of filamentous fungi and yeasts in the samples. Aflatoxins B1, B2, G1 and G2 were found in acceptable amounts and the other fungal metabolites: ergometrine, griseofulvin, festuclavin, ergine and lysergol. Concluding, the results of this study demonstrate that amount of filamentous fungi and the water activity present in the original package remain constant after six days of storage. Four types of aflatoxins were found: AFB1, AFB2, AFG1, AFG2 and the Ergot alkaloids: ergine, ergometrine, festuclavine, griseofulvin and lisergol in amounts within acceptable limits. These groups of toxic compounds produced by fungi can be present in equine feed and may lead to a risk to their health.

The diversity of fungal population from grape harvest to young wine in Small Carpathian wine region

The study aimed to identify the filamentous fungi and yeast mycobiota found on the surface and in grapes, grape must, and wine obtained from four red grape varieties: Alibernet, Dornfelder, Blue Frankish, Cabernet Sauvignon, and four white grape varieties: Green Veltliner, Rheinriesling, Pinot Blanc, Sauvignon. Grapes from vineyard Vrbové located in southwestern Slovakia were used for the research in 2020. The identification of filamentous fungi was performed using the macroscopic and microscopic observations and yeasts were identified by MALDI-TOF Mass Spectrometer. A total of 642 isolates were obtained. Grapes were rich in diversity of filamentous fungi (13 genera) and must on yeasts (8 genera). Penicillium, Botrytis, and Hanseniaspora uvarum were identified in both grapes and must. Three of the fungal genera identified by conventional or molecular techniques from the surface of red grape varieties were predominant: Alternaria (26%), Botrytis (21%), and Issatchenkia terricola (13%), two from endogenous mycobiota: Hanseniaspora uvarum (45%) and Botrytis (17%), four from the surface of white grape varieties: Penicillium (25%), Botrytis (21%), Alternaria (16%) and Hanseniaspora uvarum (15%), and three from endogenous mycobiota: Botrytis (44%), Hanseniaspora uvarum (23%) and Alternaria (20%). Saccharomyces cerevisiae, Candida krusei, C. utilis, and Cryptococcus neoformans were identified only in wine.

Antifungal Susceptibility Pattern of Non - Dermatophytic Fungi Causing Onychomycosis

Introduction: Non-dermatophytic molds (NDM) are filamentous fungi or yeast, commonly found in nature as saprophytes and plant pathogens. The incidence of onychomycosis due to NDM is 1.45 – 16.6%. NDMs are usually resistant to conventional antifungal treatment.&#x0D; Objective: To know the anti-fungal susceptibility pattern of non-dermatophyte fungi causing onychomycosis. &#x0D; Materials and Methods: A prospective hospital based cross-sectional study was done on non - dermatophytic isolates from patients with clinical suspicion of onychomycosis. All non – dermatophytic isolates were subjected to anti-fungal susceptibility against terbinafine, itraconazole, fluconazole and griseofulvin by micro broth dilution method. &#x0D; Results: NDM were isolated in 20.2% cases of clinically suspected onychomycosis, among which Fusarium species was the most common followed by Aspergillus species and Candida species. MIC50 (Mean Inhibitory Concentration) for overall non - dermatophytic isolates for terbinafine, itraconazole, fluconazole and griseofulvin was 0.25μg/mL, 0.5μg/mL, 32μg/mL and 2μg/mL respectively and the order of sensitivity was Itraconazole (74.7%) &gt; terbinafine (68%) &gt; Fluconazole (60%) &gt; Griseofulvin (51.6%) of the study samples. For Fusarium species, the sensitivity for terbinafine was (73.5%) &gt; itraconazole (67.6%) &gt; fluconazole (64.7%) and griseofulvin (64.7%). For Aspergillus species, the sensitivity for itraconazole was 79.1% &gt; fluconazole (58.3%) &gt; terbinafine (54.1%) &gt; griseofulvin (50%). For Candida species, the sensitivity was fluconazole (83.3%) &gt; itraconazole (75%) &gt; terbinafine (41.6%), while no candida species was found sensitive to griseofulvin. &#x0D; Conclusion: Non-dermatophytes play a significant role in onychomycosis. On in vitro estimation, Itraconazole was the most sensitive drug, followed by terbinafine, fluconazole and griseofulvin.

Stress Tolerance of Yeasts Dominating Reverse Osmosis Membranes for Whey Water Treatment.

Filamentous yeast species belonging to the closely related Saprochaete clavata and Magnusiomyces spicifer were recently found to dominate biofilm communities on the retentate and permeate surface of Reverse Osmosis (RO) membranes used in a whey water treatment system after CIP (Cleaning-In-Place). Microscopy revealed that the two filamentous yeast species can cover extensive areas due to their large cell size and long hyphae formation. Representative strains from these species were here further characterized and displayed similar physiological and biochemical characteristics. Both strains tested were able to grow in twice RO-filtrated permeate water and metabolize the urea present. Little is known about the survival characteristics of these strains. Here, their tolerance toward heat (60, 70, and 80°C) and Ultraviolet light (UV-C) treatment at 255 nm using UV-LED was assessed as well as their ability to form biofilm and withstand cleaning associated stress. According to the heat tolerance experiments, the D60°C of S. clavata and M. spicifer is 16.37 min and 7.24 min, respectively, while a reduction of 3.5 to >4.5 log (CFU/mL) was ensured within 5 min at 70°C. UV-C light at a dose level 10 mJ/cm2 had little effect, while doses of 40 mJ/cm2 and upward ensured a ≥4log reduction in a static laboratory scale set-up. The biofilm forming potential of one filamentous yeast and one budding yeast, Sporopachydermia lactativora, both isolated from the same biofilm, was compared in assays employing flat-bottomed polystyrene microwells and peg lids, respectively. In these systems, employing both nutrient rich as well as nutrient poor media, only the filamentous yeast was able to create biofilm. However, on RO membrane coupons in static systems, both the budding yeast and a filamentous yeast were capable of forming single strain biofilms and when these coupons were exposed to different simulations of CIP treatments both the filamentous and budding yeast survived these. The dominance of these yeasts in some filter systems tested, their capacity to adhere and their tolerance toward relevant stresses as demonstrated here, suggest that these slow growing yeasts are well suited to initiate microbial biofouling on surfaces in low nutrient environments.

Comparative study of the effect of some antiseptics, antibiotics and SNPs NPs on the inhibition of growth of filamentous fungi and yeast isolated from diabetic foo

Comparative study of the effect of some antiseptics, antibiotics and SNPs NPs on the inhibition of growth of filamentous fungi and yeast isolated from diabetic foo

New plectosphaerellaceous species from Dutch garden soil

During 2017, the Westerdijk Fungal Biodiversity Institute (WI) and the Utrecht University Museum launched a Citizen Science project. Dutch school children collected soil samples from gardens at different localities in the Netherlands, and submitted them to the WI where they were analysed in order to find new fungal species. Around 3000 fungal isolates, including filamentous fungi and yeasts, were cultured, preserved and submitted for DNA sequencing. Through analysis of the ITS and LSU sequences from the obtained isolates, several plectosphaerellaceous fungi were identified for further study. Based on morphological characters and the combined analysis of the ITS and TEF1-α sequences, some isolates were found to represent new species in the genera Phialoparvum, i.e. Ph. maaspleinense and Ph. rietveltiae, and Plectosphaerella, i.e. Pl. hanneae and Pl. verschoorii, which are described and illustrated here.

Microbial biofilm communities on Reverse Osmosis membranes in whey water processing before and after cleaning

The need for recovering valuable compounds and water from side streams has increased the use of Reverse Osmosis (RO) membrane filtration in the food industry. RO membranes, however, are highly susceptible to biofilm formation, which may decrease performance and increase industrial costs. In order to identify and characterize the biofilm forming communities, industrial RO membranes from whey water recovery lines in a dairy industry were investigated before and after Cleaning-In-Place (CIP) treatments. Phase contrast and Confocal Laser Scanning Microscopy (CLSM) were used to visualize the biofilms. The Heterotrophic Plate Count (HPC) and yeast population were enumerated, and 16S, 26S, and ITS rRNA sequencing was employed to identify the dominant isolates. A dense biofilm of the filamentous yeast species Saprochaete clavata and Magnusiomyces spicifer was observed together with budding yeasts and Gram-negative bacteria. The filamentous yeasts had long hyphae, which spatially dominated the biofilm on the retentate and permeate surface and they were not inactivated by the standard CIP treatment. Since neither plate counts nor DNA-based methods reflect the wide membrane coverage of the filamentous yeasts, their role in biofouling may easily be underestimated. We suggest that filamentous yeasts are included in further research on fouling of water treatment membranes in the dairy industry when investigating the effect of different CIP treatments or new RO membrane properties.

GC-MS based profiling of alkanes in the filamentous yeast Hyphozyma roseoniger (Moesziomyces antarcticus).

Hyphozyma roseoniger, a filamentous yeast, is used as a biocatalyst in the bio-transformation of terpenoids; however, the microorganism's endogenous ability to synthesise and metabolise hydrophobic terpenes and alkanes has not been characterised. When grown in potato dextrose broth the organism reached the stationary phase at 14 d. The non-polar fraction from cells, harvested every second day, were obtained with ethyl acetate extraction and analysed by gas chromatography with mass-spectrometric detection. Principal component-and hierarchical cluster analysis indicated growth-dependent clustering of the sample groups. A total of 26 alkanes were annotated across the different developmental stages. The major hydrocarbons comprised linear and branched structures. The dominant alkanes were all odd- or even-carbon numbered long-chain n-alkanes, C15 > C18 > C24.

Bioactivities of Flavonoids from Lopezia racemosa.

Lopezia racemosa Cav. (Onagraceae) has been used in Mexican traditional medicine to alleviate stomachache, biliary colic, urine retention, stomach cancer, and skin, dental, buccal, and urinary infections. The objective of this study was to determine the bioactivities of specific parts of the plant to scientifically confirm its traditional use. Aerial parts and flowers were macerated and subsequently extracted with hexane, chloroform, and methanol. This study was focused on the analysis of polar components, and thus the methanolic fractions were selected for further investigations. These fractions were evaluated for their antimicrobial activity using a panel of bacterial Gram-positive and -negative strains, as well as fungal strains, including filamentous fungi and yeasts. In addition, the cytotoxic activity of the extract was assessed by MTT using the human-derived monocytic THP-1 and the normal human fibroblast cell lines. Various fractions showed antimicrobial activity against various pathogens, although the most relevant were against Pseudomonas aeruginosa and Trichophyton mentagrophytes. No inhibition of yeasts was recorded. Only four fractions showed cytotoxic effects when the human-derived THP-1 and fibroblast cells were assessed. The four flavonoids isolated from the extract were luteolin, luteolin-6-C-hexoside, luteolin-8-C-hexoside, and hyperoside. The biological activities presented in this study validate some traditional uses of the plant.

Microbiota of different wine grape berries

The wine grape berries share a complex microbial ecology including filamentous fungi, yeasts and bacteria. The microbiota reveals different physiological characteristics and depends on the grape ripening stage and the availability of nutrients with different effect on wine production. The microbiota of grape berries (n = 12) was isolated and identified in the present study. The samples were collected in September 2018. Grape berries were obtained from Vrbovo vineyard located in Slovakia. The grape berries investigated belonged to Blue Frankish, Cabernet Sauvignon, Chardonnay, Dornfelder, Feteasca regala, Green Veltliner, Irsai Oliver, Mūller Thurgau, Pálava, Pinot Blanc, Rhinriesling and Welschriesling varieties. The microorganisms were cultivated on Malt extract agar (MEA) at 25 °C for five days in aerobically for microscopic filamentous fungi and Tryptone Soya agar (TSA) at 37 °C for 24 – 48 h aerobically for bacteria and yeasts. Total bacterial counts on different wine grape berries ranged from 2.57 ±0.09 in Chardonnay to 4.39 ±0.21 log CFU.g-1 in Pálava. Microscopic filamentous fungi count ranged from 1.18 ±0.03 in Blue Frankish to 2.60 ±0.17 log CFU.g-1 in Welschriesling. MALDI-TOF MS Biotyper mass spectrometry was used for identification of microorganisms (bacteria and yeasts) and microscopic filamentous fungi with manuals. The most identified microscopic fungal species was Alternaria sp., for yeasts Issatchenkia orientalis and Leuconostoc mesenteroides subsp. mesenteroides for bacteria.

Avaliação do efeito de yacon em kefir sabor morango

Este trabalho objetivou avaliar o efeito da polpa de yacon em kefir sabor morango nas concentrações de 0, 2, 4 e 6% de yacon e nos tempos 0, 14 e 28 dias de fabricação. Quanto ao número mais provável de coliformes totais e termotolerantes as amostras do tempo 28 dias apresentaram-se conforme a legislação vigente com contagens &lt; 3,0 NMP/g. A contagem de fungos filamentosos e leveduras e bactérias láticas estavam de acordo com a legislação, para leveduras as contagens entre os tratamentos variaram de 104 a 106 UFC/g. As análises físico-químicas também estavam conforme a legislação vigente, para o quesito acidez e pH, os tratamentos variaram de 0,42 a 1,05% de ácido lático a 4,09 a 4,65 respectivamente e na análise de cor foi verificado que a maioria das amostras não se alteraram com o passar do tempo. Produtos adicionados ou não de yacon apresentaram contagens de bactérias láticas entre 8,0 a 9,5 log UFC/g, indicando assim que a adição de yacon não interfere no crescimento desses microrganismos. Este tubérculo não apresentou efeito prebiótico, mas por ter sido comprovado que não influenciou nas contagens de bactérias láticas, o mesmo pode ser uma boa opção para adição ao kefir, com intuito de agregar valor nutricional ao produto, uma vez que é rico em fibras.

Physicochemical and microbiological evaluation of yoghurts marketed in Rio Pomba/MG and comparison with the parameters of the legislation

O objetivo deste trabalho foi verificar a qualidade microbiológica e físico-química de iogurtes comercializados na cidade de Rio Pomba/MG. Foram analisadas amostras de sete marcas. Para coliformes totais e termotolerantes, as amostras apresentaram valores inferiores a 2 NMP/g. Conforme a legislação vigente, quanto à contagem de bactérias láticas viáveis, apenas em uma amostra foi encontrado valor superior a 107 UFC/g. As marcas apresentaram variação de 14,12 % a 18,52 % para ESD, sendo que cinco delas estavam acima do limite preconizado pela atual legislação (15% ESD). Todas as amostras atenderam ao padrão estabelecido para acidez (0,6 a 1,5g de ácido lático/100g). Para proteínas, quatro estavam fora dos limites estabelecidos (mínimo 2,9g/100g). Além disso, quatro amostras apresentaram amido em sua composição. Em relação à contagem de fungos filamentosos e leveduras, as amostras estavam em conformidade com as normas. Assim, torna-se necessária uma fiscalização mais eficiente, haja vista que parte das marcas analisadas não atendeu aos padrões estabelecidos pela legislação em vigor.

English

Tannase is an inducible extracellular enzyme produced by filamentous fungi, yeasts, and bacteria by solid-state fermentation (SSF) or submerged fermentation (SmF). Among the filamentous fungi, Aspergillus and Penicillium are recognized as the most efficient producers of tannase. The aims of this study were to evaluate the production of tannase under SSF by isolation from Aspergillus and Penicillium preserved in the Collection of Cultures Micoteca - URM (WDCM604); select the best enzyme producer, and use the crude extract to clarify mangaba and tamarind juices. The optimal conditions were determined by using the Placket-Burman Planning (PB) and response surface methodology (RSM). All tested crops produced activity between 2088.19 and 238.93 U/gds, and Aspergillus carneus URM5577 was the best producer. Through MSR, the best parameters for producing tannase were found to be 70 h of cultivation at pH 6.0, 7% tannic acid at 28°C and, as the response variable, 5449.31 activity U/gds. The optimum purification conditions were the molecular weight of PEG 8000 (g/mol), concentration of PEG 15% (w/w), 25% citrate (w/w), and pH 8.0. Its application in mangaba juice reduced the tannin content by 49.66% after 90 min and in tamarind by 51.82% at 120 min incubation at 37°C. Key words: Tannase, agroforestry waste, Aspergillus, Penicillium.

Effects of paraffine oil on leaf and berry mycobiota on two grape varieties

Application of fungicides have advantages and also some direct or indirect disadvantages, such as imbalance and/or fungicide resistance in microbe population. To avoid these problems the development of alternative, eco-friendly methods like mostly spraying with oils are in the focus nowadays. The investigations of the effects of fungicides on microbiota in some cultivations can give a more complex view to this topic and developmental possibilities. In the present study, our aim was testing of the effects of paraffine oil (as alternative fungicide) on microbial properties (CFU and rate of filamentous fungi and yeasts) of Chardonnay and Kékfrankos leaves and berries.&#x0D; Our results from 2014 showed that the application of paraffine oil as sole spray agent can decrease the presence of saprophytic filamentous fungi on the berries of Chardonnay (susceptible for fungal infections). In the case of Kékfrankos berries opposite properties were observed, which may be the result of the absorption of oil by the thick wax layer of this variety. The oil treatment did not affect the yeast population of Chardonnay and Kékfrankos berries contrary to negative effect of the regular pesticide treatment. The selective fungicide effect of paraffine oil against filamentous fungal population caused the accumulation of yeast cells in the mycobiota of grape berries. The careful use of this yeasts in spontaneous fermentation can improve the aroma profile of wines. The year of 2015 did no prefer the growth of fungi, therefore no interesting properties were detected in the mycobiota of grape varieties. The occurence of the harmful saprophytic filamentous fungi predicted to be increased in mild climate agricultures as the result of the climate change.&#x0D; In summary, the paraffine oils are seem to be promising tools for the eco-friendly control of harmful fungi of grapes.

Mrskn7, a putative response regulator gene of Monascus ruber M7, is involved in oxidative stress response, development, and mycotoxin production

Skn7, a response regulator (RR), is associated with oxidative stress adaptation, hypo-osmotic stress response, fungicide sensitivity, cell wall biosynthesis, cell cycle regulation, sexual mating, and sporulation in many filamentous fungi and yeasts. In this study a Skn7-like protein gene mrskn7 (Monascus ruber skn7) was isolated, sequenced, and disrupted to investigate its function in M. ruber. Bioinformatics predicted that the deduced protein encoded by mrskn7 contained the conserved DNA-binding and signal-receiver domains similar to the Skn7-like protein structure in other filamentous fungi. The Δmrskn7 strain produced fewer conidia and less mycotoxin, demonstrated increased sensitivity to peroxide but the same level of osmotic resistance to NaCl and glycerol with the wild-type. Additionally, cleistothecia observed at different time point showed a different morphology between the wild-type and the Δmrskn7 strain, suggesting the involvement of mrskn7 in sexual development of M. ruber. These results indicated that mrskn7 plays important roles in asexual and sexual development, the production of mycotoxin as well as regulation of oxidative stress signal in M. ruber.

Avaliação microbiológica da linguiça artesanal bubalina produzida na Ilha do Marajó, Pará, Brasil

A linguiça artesanal bubalina é um alimento tipicamente marajoara, que se enquadra na classe de linguiça frescal. Seu processo de fabricação envolve fatores de risco microbiológico relacionados às suas características intrínsecas e aos fatores externos, como a manipulação inadequada, falta de cuidados higiênicos, bem como tratamento térmico inadequado. Diante disso, o presente trabalho tem como objetivo, analisar a qualidade microbiológica de linguiça artesanal bubalina, elaboradas e comercializadas nos municípios de Soure (Amostra L. S) e Cachoeira do Arari (Amostra L. CA), na Ilha do Marajó, Pará. Foram realizadas análises microbiológicas de Coliformes Totais, Coliformes Termotolerantes, Staphylococcus aureus, contagem padrão de bactérias aeróbias mesófilas, e contagem de fungos filamentosos e leveduras. As determinações microbiológicas foram realizadas em triplicata, seguindo os métodos oficiais de American Public Health Association. De acordo com os resultados microbiológicos, as duas amostras avaliadas apresentaram valores máximos (&gt; 1.100 NMP/g) para coliformes totais e termotolerantes. Os níveis de Staphylococcus aureus (5,7 x 104 UFC/g para a amostra L. S e 3,8 x 103 UFC/g para a amostra L. CA) estiveram próximos ao limite permitido pela legislação vigente. As mesmas também apresentaram elevada contaminação por bactérias aeróbias mesófilas, fungos filamentosos e leveduras. Dessa forma, pode-se dizer que as amostras de linguiças artesanais bubalinas encontram-se fora dos padrões microbiológicos para embutidos frescais como linguiças cruas e similares, indicando assim falha no controle higiênico-sanitário em seu processo de elaboração.

Isolamento de microrganismos e estudo da produção de lipase utilizando resíduos agroindustriais

Lipases são enzimas que vêm se destacando no cenário da biotecnologia, principalmente devido a sua capacidade em catalisar reações de hidrólise e de síntese. As lipases são produzidas por microrganismos, animais e vegetais, porém as de origem microbiana são atualmente as mais utilizadas industrialmente. Dentre os microrganismos produtores de lipases estão os fungos filamentosos, as bactérias e as leveduras. O presente trabalho objetivou o isolamento e seleção de bactérias produtoras de lipase, bem como o estudo da produção da enzima usando resíduos provenientes da agroindústria. As amostras para o isolamento foram coletadas em uma planta piloto de biodiesel. Os microrganismos foram isolados e posteriormente submetidos a testes de detecção da atividade lipásica. Após o processo de seleção, os isolados que apresentaram maior índice enzimático (IE), foram utilizados para o estudo da produção de lipase utilizando bagaço de cana-de-açúcar e bagaço de mandioca. Nesse estudo foram isolados 16 microrganismos, sendo que 75% apresentaram atividade lipolítica. Dentre os isolados selecionados como produtores de lipase, a máxima produção foi atingida com a cepa 8A quando utilizado o bagaço de mandioca durante 48 h de fermentação.

Physicochemical and microbiological aspects of honey produced in Minas Gerais State, Brazil

Samples from ten brands of floral honey produced in different cities of the state of Minas Gerais, Brazil, were analyzed for their physicochemical and microbiological characteristics. The studied parameters were humidity, reducing sugars, apparent saccharose, insoluble solids, ashes, total acidity, diastatic activity, content of hydroxymethylfurfural; counting of filamentous fungi and yeasts, of sulfite-reducing Clostridia , of Staphylococcus aureus ; Shigella spp . and Salmonella spp . detection, and numeration of total coliforms and Escherichia coli . All of these analyses followed official methodology. The physicochemical analyses indicated that a fraction of 60% (6/10) of evaluated brands were in disagreement with Brazilian legislation in, at least, one of analyzed parameters. Respecting to microbiological results, it was verified the presence of filamentous fungi and yeasts in five brands of honey; total coliforms and E. coli in two brands, and absence of any other microorganisms in all evaluated brands. Simultaneous presence of filamentous fungi and yeasts with total coliforms and E. coli was observed in one sample. The obtained results demonstrate that not all honey samples were in accordance to Brazilian legislation, and the presence of deteriorative and pathogenic microorganisms indicated a possible decrease in the product quality, and a potential risk to consumer.

Molecular basis of the regulation of iron homeostasis in fission and filamentous yeasts.

When iron load exceeds that needed by fission and filamentous yeasts, iron-regulatory GATA-type transcription factors repress genes encoding iron acquisition systems. In contrast, under iron starvation, optimization of cellular iron utilization is coordinated by a specialized regulatory subunit of the CCAAT-binding factor that fosters repression of genes encoding iron-using proteins. Despite these findings, there is still limited knowledge concerning the mechanisms by which these iron-responsive regulators respond to high- or low-iron availability. To provide a framework for understanding common and distinct properties of iron-dependent transcriptional regulators, a repertoire of their functional domains in different fungal species is presented here. In addition, discovery of interacting partners of these iron-responsive factors contributes to provide additional insight into their properties.