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1.
World J Microbiol Biotechnol ; 36(1): 4, 2019 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-31832786

RESUMO

Colletotrichum gloeosporioides, one of the main agents of mango anthracnose, causes latent infections in unripe mango, and leads to huge economic losses during storage and transport. Dimethyl trisulfide (DMTS), one of the main volatile compounds produced by some microorganisms or plants, has shown antifungal activity against some phytopathogens in previous studies, but its effects on C. gloeosporioides and mechanisms of action have not been well characterized. In fumigation trials of conidia and mycelia of C. gloeosporioides for 2, 4, 6, 8, or 10 h, at a concentration of 100 µL/L of air space in vitro, DMTS caused serious damage to the integrity of plasma membranes, which significantly reduced the survival rate of spores, and resulted in abnormal hyphal morphology. Moreover, DMTS caused deterioration of subcellular structures of conidia and mycelia, such as cell walls, plasma membranes, Golgi bodies, and mitochondria, and contributed to leakage of protoplasm, thus promoting vacuole formation. In addition, to better understand the molecular mechanisms of the antifungal activity, the global gene expression profiles of isolate C. gloeosporioides TD3 treated in vitro with DMTS at a concentration of 100 µL/L of air for 0 h (Control), 1 h, or 3 h were investigated by RNA sequencing (RNA-seq), and over 62 Gb clean reads were generated from nine samples. Similar expressional patterns for nine differentially expressed genes (DEGs) in both RNA-seq and qRT-PCR assays showed the reliability of the RNA-seq data. In comparison to the non-treated control groups, we found DMTS suppressed expression of ß-1, 3-D-glucan, chitin, sterol biosynthesis-related genes, and membrane protein-related genes. These genes related to the formation of fungal cell walls and plasma membranes might be associated with the toxicity of DMTS against C. gloeosporioides. This is the first study demonstrating antifungal activity of DMTS against C. gloeosporioides on mango by direct damage of conidia and hyphae, thus providing a novel tool for postharvest control of mango anthracnose.


Assuntos
Antifúngicos/farmacologia , Colletotrichum/efeitos dos fármacos , Mangifera/microbiologia , Sulfetos/farmacologia , Quitina/metabolismo , Colletotrichum/isolamento & purificação , Contaminação de Alimentos , Microbiologia de Alimentos , Regulação Fúngica da Expressão Gênica , Hifas/efeitos dos fármacos , Proteínas de Membrana/metabolismo , Viabilidade Microbiana , Microscopia Eletrônica de Transmissão , Micélio/efeitos dos fármacos , Doenças das Plantas/microbiologia , RNA Fúngico/genética , RNA Fúngico/isolamento & purificação , Reprodutibilidade dos Testes , Alinhamento de Sequência , Análise de Sequência de RNA , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/isolamento & purificação , Esteróis/metabolismo , beta-Glucanas/metabolismo
2.
Inhal Toxicol ; 31(13-14): 446-456, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31874574

RESUMO

Objective: Stachybotrys chartarum is a hydrophilic fungal species commonly found as a contaminant in water-damaged building materials. Although several studies have suggested that S. chartarum exposure elicits a variety of adverse health effects, the ability to characterize the pulmonary immune responses to exposure is limited by delivery methods that do not replicate environmental exposure. This study aimed to develop a method of S. chartarum aerosolization to better model inhalation exposures. Materials and methods: An acoustical generator system (AGS) was previously developed and utilized to aerosolize and deliver fungal spores to mice housed in a multi-animal nose-only exposure chamber. In this study, methods for cultivating, heat-inactivating, and aerosolizing two macrocyclic trichothecene-producing strains of S. chartartum using the AGS are described. Results and discussion: In addition to conidia, acoustical generation of one strain of S. chartarum resulted in the aerosolization of fungal fragments (<2 µm aerodynamic diameter) derived from conidia, phialides, and hyphae that initially comprised 50% of the total fungal particle count but was reduced to less than 10% over the duration of aerosolization. Acoustical generation of heat-inactivated S. chartarum did not result in a similar level of fragmentation. Delivery of dry, unextracted S. chartarum using these aerosolization methods resulted in pulmonary inflammation and immune cell infiltration in mice inhaling viable, but not heat-inactivated S. chartarum. Conclusions: These methods of S. chartarum growth and aerosolization allow for the delivery of fungal bioaerosols to rodents that may better simulate natural exposure within water-damaged indoor environments.


Assuntos
Microbiologia do Ar/normas , Poluentes Atmosféricos/isolamento & purificação , Exposição por Inalação/análise , Pulmão/microbiologia , Stachybotrys/isolamento & purificação , Aerossóis , Animais , Líquido da Lavagem Broncoalveolar/microbiologia , Feminino , Temperatura Alta , Pulmão/imunologia , Pulmão/patologia , Camundongos , Camundongos Endogâmicos , Viabilidade Microbiana , Oryza/microbiologia , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/isolamento & purificação , Esporos Fúngicos/metabolismo , Stachybotrys/crescimento & desenvolvimento , Stachybotrys/metabolismo , Tricotecenos/metabolismo
3.
J Basic Microbiol ; 59(11): 1092-1104, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31613011

RESUMO

Melanins are one of the great natural pigments produced by a wide variety of fungal species that promote fitness and cell survival in diverse hostile environments, including during mammalian infection. In this study, we sought to demonstrate the production of melanin in the conidia and hyphae of saprophytic fungi, including dematiaceous and hyaline fungi. We showed that a melanin-specific monoclonal antibody (MAb) avidly labeled the cell walls of hyphae and conidia, consistent with the presence of melanin in these structures, in 14 diverse fungal species. The conidia of saprophytic fungi were treated with proteolytic enzymes, denaturant, and concentrated hot acid to yield dark particles, which were shown to be stable free radicals, consistent with their identification as melanins. Samples obtained from patients with fungal keratitis due to Fusarium falciforme, Aspergillus fumigatus, Aspergillus flavus, Curvularia lunata, Exserohilum rostratum, or Fonsecaea pedrosoi were found to be intensely labeled by the melanin-specific MAb at the fungal hyphal cell walls. These results support the hypothesis that melanin is a common component that promotes survival under harsh conditions and facilitates fungal virulence. Increased understanding of the processes of melanization and the development of methods to interfere with pigment formation may lead to novel approaches to combat these complex pathogens that are associated with high rates of morbidity and mortality.


Assuntos
Fungos/metabolismo , Melaninas/biossíntese , Micoses/microbiologia , Anticorpos Monoclonais/imunologia , Parede Celular/metabolismo , Fungos/isolamento & purificação , Humanos , Hifas/isolamento & purificação , Hifas/metabolismo , Ceratite/microbiologia , Melaninas/imunologia , Esporos Fúngicos/isolamento & purificação , Esporos Fúngicos/metabolismo
4.
An Acad Bras Cienc ; 91(4): e20180165, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31644640

RESUMO

Arbuscular Mycorrhizae (AM) are mutualistic associations between Arbuscular Mycorrhizal Fungi (AMF) and the roots of many plant species. AMF spores give rise to filaments that develop in the root system of plants and contribute to the absorption of water and some nutrients. This article introduces a semi-automated counting model of AMF spores in slide images based on Artificial Neural Network (ANN). The semi-automated counting of AMF spores facilitates and accelerates the tasks of researchers, who still do the AMF spore counting manually. We built a representative database of spore images, processing images through the Circle Hough Transform (CHT) method and training an ANN to classify patterns automatically. The classification analysis and the performances of the proposed method against the manual method are presented in this paper. The accuracy for the identification of spores by CHT in conjunction to ANN classification in the images was 90%. The results indicate that this method can accurately detect the presence of AMF spores in images as well as count them with a high level of confidence.


Assuntos
Micorrizas/isolamento & purificação , Raízes de Plantas/microbiologia , Microbiologia do Solo , Esporos Fúngicos/isolamento & purificação , Algoritmos , Redes Neurais de Computação
6.
Braz J Microbiol ; 50(4): 899-903, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31435853

RESUMO

The savanna cashew (Anacardium humile A. St. Hil.) nut is a native shrub species distributed in the savanna biome of Central Western Brazil. This species is similar to the cashew (Anacardium occidentale L.) nut, and its edible pseudo-fruits have been used for various purposes. However, A. humile is at risk of extinction. One reason for this is the phytosanitary issues. Therefore, phytosanitary studies of the serious plant diseases caused by fungal pathogens are necessary. The aim of this study was to survey the savanna cashew nut (Anacardium humile) in Central Western Brazil from August 2013 to October 2014. Serious damage caused by anthracnose to the plant's leaves and fruits was consistently detected. The pathogen fungal species was Colletotrichum gloeosporioides. It was identified by morphological characteristics and molecular analyses. Additional experiments showed evidence that C. gloeosporioides can be transmitted by cashew seeds. We observed anthracnose symptoms on the surfaces of the floral peduncle, leaves, and peduncle of the A. humile cashew nuts. The genomic DNA sequences of the selected strains for molecular characterization have had 99% identity with the analogous sequences of C. gloeosporioides. Naturally occurring C. gloeosporioides infection of the leaves of A. humile was low (20.3%) compared with that of the nuts (79.7%). Our results can be used to design strategies to prevent the introduction and establishment of C. gloeosporioides in new areas. They can also be helpful in monitoring programs in areas with a current occurrence of C. gloeosporioides. Finally, these results can be used in future research plans of C. gloeosporioides infection management.


Assuntos
Anacardium/microbiologia , Colletotrichum/isolamento & purificação , Doenças das Plantas/microbiologia , Brasil , Colletotrichum/classificação , Colletotrichum/genética , Colletotrichum/crescimento & desenvolvimento , Nozes/microbiologia , Filogenia , Folhas de Planta/microbiologia , Esporos Fúngicos/genética , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/isolamento & purificação
7.
Braz J Microbiol ; 50(4): 1011-1020, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31396863

RESUMO

Positive feedback between arbuscular mycorrhizal fungal (AMF) and vascular plants can contribute to plant species establishment, but how this feedback affects plant invasion by Prosopis juliflora SW. (DC.), or resistance to invasion by Mimosa tenuiflora (Willd.) Poir in Brazilian semi-arid region is not well known. In this work, we tested how modified and native AMF communities affect the establishment of P. juliflora and M. tenuiflora plants. We examined the effects of inoculation with modified and native AMF communities on number of AMF spores, root colonization, number of N-fixing nodules, plant dry biomass, plant phosphorous concentration, and plant responsiveness to mycorrhizas of P. juliflora and M. tenuiflora. We found that the modified AMF community enhanced the root colonization, plant dry biomass, and plant phosphorous concentration of invasive P. juliflora, whereas native AMF enhanced M. tenuiflora. Our results demonstrate that the invasive P. juliflora alters soil AMF community composition, and this change generates positive feedback to the invasive P. juliflora itself and decreases AMF associations with native M. tenuiflora.


Assuntos
Fabaceae/microbiologia , Fungos/isolamento & purificação , Mimosa/microbiologia , Micorrizas/isolamento & purificação , Biodiversidade , Brasil , Fabaceae/crescimento & desenvolvimento , Fungos/classificação , Fungos/genética , Fungos/metabolismo , Espécies Introduzidas , Mimosa/crescimento & desenvolvimento , Micorrizas/classificação , Micorrizas/genética , Micorrizas/metabolismo , Fósforo/metabolismo , Raízes de Plantas/microbiologia , Solo/química , Microbiologia do Solo , Esporos Fúngicos/classificação , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/isolamento & purificação , Esporos Fúngicos/metabolismo
8.
Appl Microbiol Biotechnol ; 103(18): 7767-7782, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31388730

RESUMO

Exposure to bioaerosols can adversely influence human health through respiratory tract, eye, and skin irritation. Bioaerosol composition is unique on the International Space Station (ISS), where the size distribution of particles in the air differs from those on Earth. This is due to the lack of gravitational settling and sources of biological particles. However, we do not understand how microbes are influenced by particle size in this environment. We analyzed two types of samples from the ISS: (1) vacuum bag debris which had been sieved into five different size fractions and (2) passively collected particles on a tape substrate with a passive aerosol sampler. Using quantitative polymerase chain reaction (qPCR), the highest concentration of fungal spores was found in the 106-150 µm-sized sieved dust particles, while the highest concentration of bacterial cells was found in the 150-250 µm-sized sieved dust particles. Illumina MiSeq DNA sequencing revealed that particle size was associated with bacterial and fungal communities and statistically significant (p = 0.035, p = 0.036 respectively). Similar fungal and bacterial species were found within the passive aerosol sample and the sieved dust samples. The most abundant fungal species identified in the aerosol and sieved samples are commonly found in food and plant material. Abundant bacterial species were most associated with the oral microbiome and human upper respiratory tract. One limitation to this study was the suboptimal storage conditions of the sieved samples prior to analysis. Overall, our results indicate that microbial exposure in space may depend on particle size. This has implications for ventilation and filtration system design for future space vehicles and habitats.


Assuntos
Aerossóis/análise , Microbiologia do Ar , Poeira/análise , Microbiota , Tamanho da Partícula , Astronave , Bactérias/genética , Bactérias/isolamento & purificação , Monitoramento Ambiental , Humanos , Internacionalidade , Sistema Respiratório/microbiologia , Análise de Sequência de DNA , Esporos Fúngicos/genética , Esporos Fúngicos/isolamento & purificação
9.
J Sci Food Agric ; 99(14): 6589-6600, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31328271

RESUMO

BACKGROUND: Rice smut and rice blast are listed as two of the three major diseases of rice. Owing to the small size and similar structure of rice blast and rice smut spores, traditional microscopic methods are troublesome to detect them. Therefore, this paper uses microscopy image identification based on the synergistic judgment of texture and shape features and the decision tree-confusion matrix method. RESULTS: The distance transformation-Gaussian filtering-watershed algorithm method was proposed to separate the adherent rice blast spores, and the accuracy was increased by about 10%. Four shape features (area, perimeter, ellipticity, complexity) and three texture features (entropy, homogeneity, contrast) were selected for decision-tree model classification. The confusion-matrix algorithm was used to calculate the classification accuracy, in which global accuracy is 82% and the Kappa coefficient is 0.81. At the same time, the detection accuracy is as high as 94%. CONCLUSIONS: The synergistic judgment of texture and shape features and the decision tree-confusion matrix method can be used to detect rice disease quickly and precisely. The proposed method can be combined with a spore trap, which is vital to devise strategies early and to control rice disease effectively. © 2019 Society of Chemical Industry.


Assuntos
Fungos/isolamento & purificação , Processamento de Imagem Assistida por Computador/métodos , Microscopia/métodos , Oryza/microbiologia , Doenças das Plantas/microbiologia , Esporos Fúngicos/citologia , Algoritmos , Árvores de Decisões , Fungos/química , Fungos/citologia , Microscopia/instrumentação , Esporos Fúngicos/química , Esporos Fúngicos/isolamento & purificação
10.
Analyst ; 144(16): 4962-4971, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31322144

RESUMO

The research of fungi is of great importance in a number of fields, such as environmental and healthcare studies. While there are a large number of optical and molecular methods available for characterization and identification of fungi and their spores, their isolation is still conducted using slow and labor-intensive methods. Here, we develop a microfluidic device for the continuous separation of fungal spores from other eukaryotic cells. The spores were separated through the microfluidic device by expanding pinched flow fractionation (PFF) containing the spores, achieving a spatial separation perpendicular to the flow direction according to the spore size. Further branch flow fractionation (BFF) and co-flow of a Newtonian and viscoelastic fluid were used to enhance the separation performance. Using this microfluidic device, we demonstrated the separation of two different types of fungal spores and further separation of fungal spores from eukaryotic cells with a separation efficiency of above 90%. Compared to the existing conventional methods, our microfluidic flow focusing device requires little manual handling and uses small amounts of samples without any pre-treatment steps of the samples.


Assuntos
Dispositivos Lab-On-A-Chip , Esporos Fúngicos/isolamento & purificação , Alternaria/isolamento & purificação , Aspergillus niger/isolamento & purificação , Fracionamento Químico/instrumentação , Fracionamento Químico/métodos , Cladosporium/isolamento & purificação , Desenho de Equipamento , Técnicas Analíticas Microfluídicas/instrumentação , Técnicas Analíticas Microfluídicas/métodos
11.
Trop Doct ; 49(4): 306-308, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31179890

RESUMO

Cutaneous chrysosporium infection is extremely rare and underdiagnosed. We present an immunocompromised patient who presented with recurrent cutaneous abscesses. Histopathology of the abscess showed thick-walled conidia and septate fungal hyphae within the subcutis and fungal culture grew Chrysosporium species.


Assuntos
Abscesso/diagnóstico , Abscesso/etiologia , Chrysosporium/fisiologia , Dermatomicoses/complicações , Dermatomicoses/diagnóstico , Abscesso/imunologia , Abscesso/microbiologia , Adulto , Chrysosporium/crescimento & desenvolvimento , Chrysosporium/isolamento & purificação , Dermatomicoses/imunologia , Dermatomicoses/microbiologia , Humanos , Hospedeiro Imunocomprometido , Masculino , Recidiva , Pele/microbiologia , Pele/patologia , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/isolamento & purificação
12.
Int J Parasitol ; 49(8): 657-667, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31170411

RESUMO

Nosema ceranae is the most prevalent endoparasite of Apis mellifera iberiensis and it is a major health problem for bees worldwide. The infective capacity of N. ceranae has been demonstrated experimentally in honey bee brood, however no data are available about its prevalence in brood under natural conditions. Thus, brood combs from 10 different hives were analyzed over two consecutive years, taking samples before and after winter. A total of 1433 larvae/pupae were analyzed individually and N. ceranae (3.53%) was the microsporidian most frequently detected, as opposed to Nosema apis (0.42%) which was more frequently detected in conjunction with N. ceranae (0.71%). The active multiplication of both microsporidians was confirmed by the expression (real-time-PCR) of the N. ceranae polar tube protein 3 gene and/or the N. apis RNA polymerase II gene in 24% of the brood samples positive for Nosema spp. Both genes are related to microsporidian multiplication. As such, N. ceranae multiplication was confirmed in 1.06% of the samples, while N. apis multiplication was only observed in co-infections with N. ceranae (0.07%). Brood cells were analyzed for the presence of Nosema spp., as those are the immediate environment where the brood stages develop. The brood samples infected by Nosema spp. were in brood cells in which that microsporidians were not detected, while brood cells positive for N. ceranae hosted brood stages that were not apparently infected, indicating that this is unlikely to be the main pathway of infection. Finally, the colonies with brood infected by N. ceranae showed higher levels (numbers) of infected adult bees, although the differences were not significant before (P = 0.260), during (P = 0.055) or after (P = 0.056) brood sampling. These results show that N. ceranae is a bee parasite ubiquitous to all members of the colony, irrespective of the age of the bee. It is also of veterinary interest and should be considered when studying the epidemiology of the disease.


Assuntos
Abelhas/parasitologia , Nosema/crescimento & desenvolvimento , Animais , Abelhas/enzimologia , Abelhas/genética , Abelhas/crescimento & desenvolvimento , DNA Fúngico/química , DNA Fúngico/isolamento & purificação , Proteínas Fúngicas/genética , Larva/parasitologia , Nosema/genética , Nosema/isolamento & purificação , Pupa/parasitologia , RNA Polimerase II/genética , Reação em Cadeia da Polimerase em Tempo Real , Reprodutibilidade dos Testes , Esporos Fúngicos/genética , Esporos Fúngicos/isolamento & purificação
13.
Int. microbiol ; 22(2): 191-201, jun. 2019. ilus, graf, tab
Artigo em Inglês | IBECS | ID: ibc-184826

RESUMO

In this study, endophytic bacteria isolated from root, stem, and leaf tissues of stripe rust-susceptible (Inqilab 91, Galaxy 2013, and 15BT023) and stripe rust-resistant (NARC 2011, Ujala 2015, TW1410) cultivars were identified and characterized. Abundance of endophytes was found in roots as compared with stems and leaves. Resistant and susceptible cultivars significantly differed in abundance of endophytic bacteria. Restriction analysis of 16S rRNA genes amplified from 100 bacterial isolates produced 17 unique patterns. Representatives of each of the 17 unique patterns were sequenced and identified. Among the sequenced bacteria, 8 belonged to Firmicutes, 7 were Proteobacteria, and 2 were Actinobacteria. Most of the isolates have plant growth-promoting properties and a few have the potential of producing hydrolytic enzymes. Two isolates showed significant inhibition of rust spore germination. These endophytic bacteria not only can be helpful in growth-promoting activities but also can assist in biocontrol of stripe rust disease


No disponible


Assuntos
Endófitos/isolamento & purificação , Raízes de Plantas/microbiologia , Phakopsora pachyrhizi/isolamento & purificação , RNA Ribossômico 16S/isolamento & purificação , Bactérias/isolamento & purificação , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/metabolismo , Firmicutes/isolamento & purificação , Actinobacteria/enzimologia , Actinobacteria/isolamento & purificação , Esporos Bacterianos/crescimento & desenvolvimento , Esporos Fúngicos/isolamento & purificação , Paquistão
14.
Indoor Air ; 29(5): 780-790, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31106451

RESUMO

Experimental aerosolization studies revealed that fungal fragments including small fragments in the submicrometer size are released from fungal cultures and have been suggested to represent an important fraction of overall fungal aerosols in indoor environments. However, their prevalence indoors and outdoors remains poorly characterized. Moldy basements were investigated for airborne fungal particles including spores, submicron fragments, and larger fragments. Particles were collected onto poly-L-lysine-coated polycarbonate filters and qualitatively and quantitatively analyzed using immunogold labeling combined with field emission scanning electron microscopy. We found that the total fungal aerosol levels including spores, submicrometer, and larger fragments in the moldy basements (median: 80 × 103  m-3 ) were not different from that estimated in control basements (63 × 103  m-3 ) and outdoor (90 × 103  m-3 ). However, mixed effect modeling of the fungal aerosol composition revealed that the fraction of fragments increased significantly in moldy basements, versus the spore fraction that increased significantly in outdoor air. These findings provide new insight on the compositional variation of mixed fungal aerosols in indoor as compared to outdoor air. Our results also suggest that further studies, aiming to investigate the role of fungal aerosols in the fungal exposure-disease relationships, should consider the mixed composition of various types of fungal particles.


Assuntos
Aerossóis/análise , Microbiologia do Ar , Poluição do Ar em Ambientes Fechados/análise , Fungos/isolamento & purificação , Monitoramento Ambiental/métodos , Habitação , Humanos , Noruega , Estações do Ano , Esporos Fúngicos/isolamento & purificação
15.
Artigo em Inglês | MEDLINE | ID: mdl-30972306

RESUMO

Paraphysoderma sedebokerense (P. sedebokerense) (Blastocladiomycota) is a facultative pathogenic chytrid that causes irreversible damage to some green microalgae. Specific attacks leading to culture collapse under different conditions have only been described in the lucrative microalga Haematococcus pluvialis (H. pluvialis), while generating biomass for ketocarotenoid astaxanthin production, both indoors and outdoors. In order to manage the infection, parasite propagules (zoospores/amoeboid swarmers), the initiators of the disease, must be studied. Until now, no report on isolated P. sedebokerense propagules has been published. Here, we report on a reproducible method for the stimulation of P. sedebokerense propagule release and their isolation from fungal cultures in synthetic media and infected H. pluvialis cultures, and we further studied their development under different conditions. The isolated propagules featured different spore morphotypes, with coatless spherical spores and amoeboid swarmers being the most dominant in the first pulse of propagule release in both cultures. Inoculating the pure propagules with the host, in both the presence and absence of nitrogen, resulted in epidemic development in both green and red cells; however, in red cells, the epidemic developed more quickly in the presence of nitrogen. Biologically non-active autoclaved host cells were used to distinguish the initial stages of recognition from more progressive stages of the epidemics; on these cells, propagules encysted but did not develop further. These results prove the existence of heat-stable recognition sites on the host and an obligatory signal transduction from the host to support fungal cyst development. The propagule isolation method described herein is a breakthrough that will enable researchers to study the influence of different substances on the propagules, specifically as the initiators of the infection, and thus assist in the management of chytrid diseases. Moreover, it will be useful in studying host-parasite recognition and, therefore, will increase our understanding of the multiple chytrid infections found in nature.


Assuntos
Blastocladiomycota/crescimento & desenvolvimento , Blastocladiomycota/isolamento & purificação , Clorofíceas/microbiologia , Técnicas Microbiológicas/métodos , Blastocladiomycota/citologia , Exposição Ambiental , Esporos Fúngicos/citologia , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/isolamento & purificação , Temperatura
16.
Plant Dis ; 103(7): 1464-1473, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30998450

RESUMO

Colletotrichum Corda, 1831 species are well-documented pathogens of citrus that are associated with leaf and fruit anthracnose diseases. However, their role in twig and shoot dieback diseases of citrus has recently become more prominent. Recent surveys of orchards in the Central Valley of California have revealed C. gloeosporioides and a previously undocumented species, C. karstii, to be associated with twig and shoot dieback. Pathogenicity tests using clementine (cv. 4B) indicated that both C. karstii and C. gloeosporioides are capable of producing lesions following inoculation of citrus stems. Pathogenicity tests also revealed C. karstii to be the most aggressive fungal species producing the longest lesions after 15 months. The majority of spores trapped during this study were trapped during or closely following a precipitation event with the majority of spores being trapped from January through May. These findings confirm C. karstii as a new pathogen of citrus in California.


Assuntos
Colletotrichum , Virulência , California , Colletotrichum/classificação , Colletotrichum/patogenicidade , Colletotrichum/fisiologia , Doenças das Plantas/microbiologia , Esporos Fúngicos/isolamento & purificação
17.
Food Microbiol ; 82: 551-559, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31027818

RESUMO

Moldy food products that are not subject to pathogenic bacterial contamination could be trimmed by consumers to remove fungal mycelium before consumption. However, prior to giving such recommendations to consumers, it is necessary to evaluate potential mycotoxin migration in these products. This study aimed at quantifying citrinin (CIT) and ochratoxin A (OTA) accumulation and migration in a French semi-hard Comté cheese after artificial inoculation with a CIT- and OTA-producing Penicillium verrucosum strain. At 8 °C, CIT and OTA production started after 14 days and 28 days incubation, respectively; while at 20 °C, both mycotoxins were produced from day 7. At 20 °C, maximum CIT concentration, about 50000 ng/g, was 20 fold that at 8 °C. Regardless of temperature, maximum OTA concentration was about 4000 ng/g cheese. Maximum concentrations were obtained in the upper part of the cheese, but depending on incubation time, mycotoxins were detected up to 1.6 cm in depth. As long as only white mycelium developed on the cheese surface, trimming can be acceptable, but a blue mold color (due to fungal sporulation) was associated with the accumulation of significant amounts of mycotoxins so the product should be discarded.


Assuntos
Queijo/microbiologia , Citrinina/biossíntese , Microbiologia de Alimentos , Ocratoxinas/biossíntese , Penicillium/metabolismo , Queijo/análise , Citrinina/análise , Inocuidade dos Alimentos , França , Micotoxinas/análise , Micotoxinas/biossíntese , Ocratoxinas/análise , Penicillium/crescimento & desenvolvimento , Penicillium/isolamento & purificação , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/isolamento & purificação , Esporos Fúngicos/metabolismo , Temperatura
18.
Food Microbiol ; 81: 108-114, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30910081

RESUMO

Fungi are able to grow on diverse food products and contribute to food spoilage worldwide causing food loss. Consumers prefer freshly squeezed fruit juices, however, the shelf life of these juices is limited due to outgrowth of yeast and fungi. The shelf life of pulsed electric field (PEF) treated juice can be extended from 8 days up to a few weeks before spoilage by moulds becomes apparent. Conidia produced by three Penicillium ssp. (Penicillium expansum, Penicillium buchwaldii and Penicillium bialowiezense), previously isolated from spoiled PEF treated fruit juice and smoothie, were characterized for resistance towards selected mild physical processing techniques in orange juice and toward sanitizers on surfaces. The results show that Penicillium spp. conidia are susceptible to mild heat, high pressure pasteurization (HPP), PEF, cold atmospheric plasma (CAP), UV, and chemical sanitizers chlorine dioxide and hypochlorite albeit with different susceptibility. Treatment with mild heat, HPP, PEF, or chlorine dioxide reduced conidia by more than 5 log. For hypochlorite, UV, and CAP the reduction was between 1 and 3 log. Together, this study provides data for the development of intervention strategies to eliminate spoilage mould conidia in fruit juices.


Assuntos
Desinfecção/métodos , Conservação de Alimentos/métodos , Sucos de Frutas e Vegetais/microbiologia , Penicillium/efeitos dos fármacos , Penicillium/efeitos da radiação , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/efeitos da radiação , Compostos Clorados/farmacologia , Citrus sinensis , Eletricidade , Manipulação de Alimentos , Armazenamento de Alimentos , Temperatura Alta , Ácido Hipocloroso/farmacologia , Testes de Sensibilidade Microbiana , Óxidos/farmacologia , Pasteurização/métodos , Penicillium/crescimento & desenvolvimento , Penicillium/isolamento & purificação , Gases em Plasma/farmacologia , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/isolamento & purificação , Raios Ultravioleta
19.
Appl Environ Microbiol ; 85(9)2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30824432

RESUMO

There are limitations in establishing a direct link between fungal exposure and health effects due to the methodology used, among other reasons. Culture methods ignore the nonviable/uncultivable fraction of airborne fungi. Molecular methods allow for a better understanding of the environmental health impacts of microbial communities. However, there are challenges when applying these techniques to bioaerosols, particularly to fungal cells. This study reveals that there is a loss of fungal cells when samples are recovered from air using wet samplers and aimed to create and test an improved protocol for concentrating mold spores via filtration prior to DNA extraction. Results obtained using the new technique showed that up to 3 orders of magnitude more fungal DNA was retrieved from the samples using quantitative PCR. A sequencing approach with MiSeq revealed a different diversity profile depending on the methodology used. Specifically, 8 fungal families out of 19 families tested were highlighted to be differentially abundant in centrifuged and filtered samples. An experiment using laboratory settings showed the same spore loss during centrifugation for Aspergillus niger and Penicillium roquefortii strains. We believe that this work helped identify and address fungal cell loss during processing of air samples, including centrifugation steps, and propose an alternative method for a more accurate evaluation of fungal exposure and diversity.IMPORTANCE This work shed light on a significant issue regarding the loss of fungal spores when recovered from air samples using liquid medium and centrifugation to concentrate air particles before DNA extraction. We provide proof that the loss affects the overall fungal diversity of aerosols and that some taxa are differentially more affected than others. Furthermore, a laboratory experiment confirmed the environmental results obtained during field sampling. The filtration protocol described in this work offers a better description of the fungal diversity of aerosols and should be used in fungal aerosol studies.


Assuntos
Microbiologia do Ar , Poluição do Ar em Ambientes Fechados/análise , Aspergillus niger/isolamento & purificação , Monitoramento Ambiental/métodos , Penicillium/isolamento & purificação , Esporos Fúngicos/isolamento & purificação , Fungos/isolamento & purificação
20.
Sci Total Environ ; 653: 938-946, 2019 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-30759619

RESUMO

Airborne fungal spores are prevalent components of bioaerosols with a large impact on ecology, economy and health. Their major socioeconomic effects could be reduced by accurate and timely prediction of airborne spore concentrations. The main aim of this study was to create and evaluate models of Alternaria and Cladosporium spore concentrations based on data on a continental scale. Additional goals included assessment of the level of generalization of the models spatially and description of the main meteorological factors influencing fungal spore concentrations. Aerobiological monitoring was carried out at 18 sites in six countries across Europe over 3 to 21 years depending on site. Quantile random forest modelling was used to predict spore concentrations. Generalization of the Alternaria and Cladosporium models was tested using (i) one model for all the sites, (ii) models for groups of sites, and (iii) models for individual sites. The study revealed the possibility of reliable prediction of fungal spore levels using gridded meteorological data. The classification models also showed the capacity for providing larger scale predictions of fungal spore concentrations. Regression models were distinctly less accurate than classification models due to several factors, including measurement errors and distinct day-to-day changes of concentrations. Temperature and vapour pressure proved to be the most important variables in the regression and classification models of Alternaria and Cladosporium spore concentrations. Accurate and operational daily-scale predictive models of bioaerosol abundances contribute to the assessment and evaluation of relevant exposure and consequently more timely and efficient management of phytopathogenic and of human allergic diseases.


Assuntos
Microbiologia do Ar/normas , Poluentes Atmosféricos/análise , Alternaria/fisiologia , Cladosporium/fisiologia , Conceitos Meteorológicos , Esporos Fúngicos/isolamento & purificação , Poluentes Atmosféricos/imunologia , Poluição do Ar/análise , Alérgenos/análise , Alérgenos/imunologia , Alternaria/imunologia , Cladosporium/imunologia , Monitoramento Ambiental/estatística & dados numéricos , Europa (Continente) , Previsões , Modelos Estatísticos , Esporos Fúngicos/imunologia
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