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1.
Mol Biol Rep ; 50(7): 6049-6061, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37294469

RESUMEN

BACKGROUND: Geotrichum is a genus of fungi found in different habitats throughout the world. Although Geotrichum and its related species have been extensively reclassified and taxonomically revised, it is still the target for many researches. METHODS AND RESULTS: In this study, phenotypic and molecular genetics comparisons were performed between Geotrichum candidum and Geotrichum silvicola. Mitis Salivarius Agar was used as the growing medium for the phenotypic comparison study, which was carried out at two temperatures (20-25 and 37 °C). For genotypic comparison, we compared the 18 S, ITS, and 28 S sequences of universal DNA barcode regions of both species. Important findings on the new culture media for fungal isolation were revealed by the results. The phenotypic variation between the two species' colonies, including their shapes, sizes, textures and growth rates, were strikingly different. DNA sequences of both species showed that pairwise identities of the species were 99.9% for 18 S, 100% for ITS and 99.6% for 28 S regions. CONCLUSIONS: Contrary to what is commonly seen, the results showed that 18 S, ITS and 28 S failed to discriminate the species. The first investigation into the performance of Mitis Salivarius Agar as a fungus culture medium is reported in this work, and proved its efficiency. Additionally, this is the first study to compare G. candidum with G. silvicola by means of both phenotypic and genotypic analysis.


Asunto(s)
Geotrichum , Pimenta , Geotrichum/genética , Agar , Biología Molecular
2.
Genomics ; 112(6): 4063-4071, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-32650101

RESUMEN

Sour rot, caused by Geotrichum citri-aurantii, is a major postharvest disease of citrus,and it causes serious economic losses. In this study, a high-quality genome sequence of G. citri-aurantii was obtained by Single Molecule Real-Time Sequencing (SMRT). Approximately 5.43 Gb of clean data were obtained and a total of 27.94-Mb genomic sequence was mapped to 10 chromosome groups after high-through chromosome conformation capture (Hi-C) assembly. In addition, three polygalacturonase genes which were related to pathogenicity in G. citri-aurantii genome were discovered. And transcriptome data of guazatine-resistance had been analyzed, the results showed that the guazatine-resistance of G. citri-aurantii was related to two ATP-binding cassette (ABC) transporter family genes, six major facilitator superfamily (MFS) transporter family genes and two multidrug and toxic compound extrusion (MATE) transporter family genes. In summary, our research may provide novel insights into the effective control of this pathogen.


Asunto(s)
Citrus/microbiología , Fungicidas Industriales/farmacología , Genoma Fúngico , Geotrichum/genética , Guanidinas/farmacología , Farmacorresistencia Fúngica/genética , Perfilación de la Expresión Génica , Genes Fúngicos , Genómica , Geotrichum/efectos de los fármacos , Geotrichum/metabolismo , Geotrichum/patogenicidad , Proteínas de Transporte de Membrana/genética , Poligalacturonasa/genética
3.
Enzyme Microb Technol ; 138: 109563, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32527532

RESUMEN

Cheese lacks essential fatty acids (EFAs). Delta 12 fatty acid desaturase (FADS12) is a critical enzyme required for EFA biosynthesis in fermentation of the predominant strains of cheese. Previously, we identified the FADS12 gene and characterized its function for the first time in Geotrichum candidum, a dominant strain used to manufacture soft cheese with white rind. In this study, we analyzed the molecular mechanism of FADS12 function by swapping domains from Mortierella alpina and G. candidum that had, respectively, high and low oleic acid conversion rates. The results revealed three regions that are essential to this process, including regions from the end of the second transmembrane domain to the beginning of the third transmembrane domain, from the end of the third transmembrane domain to the beginning of the fourth transmembrane domain, and from the 30-amino acid from the end of the sixth transmembrane domain to the C-terminal end region. Based on our domain swapping analyses, nine pairs of amino acids including H112, S118, H156, Q161, K301, R306, E307, A309 and S323 in MaFADS12 (K123, A129, N167, M172, T302, D307, I308, E310 and D324 in GcFADS12) were identified as having a significantly effect on FADS12 catalytic efficiency, and linoleic acid and its analogues (12,13-cyclopropenoid fatty acid) were found to inhibit the catalytic activity of FADS12 and related recombinant enzymes. Furthermore, the molecular mechanism of FADS12 inhibition was analyzed. The results revealed two allosteric domains, including one domain from the N-terminal region to the beginning of the first transmembrane domain and another from the 31st amino acid from the end of the sixth transmembrane domain to the C terminus. Y4 and F398 amino acid residues from MaFADS12 and eight pairs of amino acids including G56, L60, L344, G10, Q13, S24, K326 and L344 in MaFADS12 (while Y66, F70, F345, F20, Y23, Y34, F327 and F345 in GcFADS12) played a pivotal role in FADS12 inhibition. Finally, we found that both allosteric and active sites were responsible for the catalytic activity of FADS12 at various temperatures, pH, and times. This study offers a solid theoretical basis to develop preconditioning methods to increase the rate at which GcFADS12 converts oleic and linoleic acids to produce higher levels of EFAs in cheese.


Asunto(s)
Ácido Graso Desaturasas/química , Ácido Graso Desaturasas/metabolismo , Geotrichum/enzimología , Mortierella/enzimología , Sitio Alostérico , Biocatálisis , Dominio Catalítico , Estabilidad de Enzimas , Ácido Graso Desaturasas/genética , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Geotrichum/genética , Concentración de Iones de Hidrógeno , Ácido Linoleico/metabolismo , Mortierella/genética , Ácido Oléico/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Temperatura , Factores de Tiempo
4.
5.
Appl Microbiol Biotechnol ; 103(23-24): 9529-9541, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31720775

RESUMEN

Enzyme engineering has been widely employed to tailor the substrate specificity and enantioselectivity of enzymes. In this study, we mutated Trp288, an unconserved residue in the small binding pocket of an acetophenone reductase from Geotrichum candidum NBRC 4597 (GcAPRD). Trp288 mutants showed substrate specificity expansion towards bulky-bulky ketones and enantioselectivity alteration which was highly dependent on the substrate substituent length. In aliphatic ketone reduction, enantioselectivity inverted from (S) to (R) when one of the substituents to the carbonyl carbon was elongated from propyl to butyl or pentyl. The best (R)-selective mutant, Trp288Val, achieved the reduction of 3-heptanone to its corresponding (R)-alcohol with 97% ee. Our docking simulation suggested that when enantioselectivity inverted to (R), only pro-R binding poses were productive. Gly94 played an important role to stabilize the butyl or pentyl group for their productive pro-R poses. Interestingly, when the substituent was further elongated, the enantioselectivity inverted back to the (S) form.


Asunto(s)
Acetofenonas/metabolismo , Oxidorreductasas de Alcohol/genética , Oxidorreductasas de Alcohol/metabolismo , Geotrichum/enzimología , Cetonas/química , Sitios de Unión , Biocatálisis , Geotrichum/genética , Cinética , Simulación del Acoplamiento Molecular , Mutagénesis Sitio-Dirigida , Oxidación-Reducción , Estereoisomerismo , Especificidad por Sustrato
6.
J Food Biochem ; 43(3): e12745, 2019 03.
Artículo en Inglés | MEDLINE | ID: mdl-31353560

RESUMEN

Sour rot is a leading disease of citrus fruit caused by the postharvest pathogen Geotrichum citri-aurantii. It has been reported that essential oils can be used as substitutes for synthetic fungicides to control the pathogen. In this study, changes in metabolites and antifungal effects of G. citri-aurantii treated with peppermint oil (PO) were investigated. The inhibition rate of the mycelial growth increased as the PO concentration increased, and 6 µl PO/disk resulted in a radial growth inhibition of 79.2%. The electrical conductivity of G. citri-aurantii treated with PO increased compared to the control. By comparing the metabolic profiles of treated and untreated G. citri-aurantii cells, a total of 53 distinct metabolites 9 were up-regulated and 44 were down-regulated were found, including 16 lipid metabolites, 6 carbohydrate metabolites, 2 amino acid metabolites, 5 alcohols, 2 glycoside metabolites, and 3 ketone metabolites, etc, and these metabolites are involved in 25 major metabolic pathways. PRACTICAL APPLICATIONS: Chemical fungicides can effectively control G. citri-aurantii during fruit postharvest period. However, synthetic chemical fungicides have gradually led to buildup of resistance of fungil, which seriously causes the frequent of food-borne diseases. PO extracted from natural plants can be used as natural additive in many foods due to their antioxidant, antibacterial, and antifungal properties. Therefore, PO can be considered as a promising bacteriostatic agent for the defense of G. citri-aurantii during fruit postharvest period.


Asunto(s)
Proteínas Fúngicas/genética , Fungicidas Industriales/farmacología , Geotrichum/química , Geotrichum/efectos de los fármacos , Aceites de Plantas/farmacología , Cromatografía Líquida de Alta Presión , Citrus/microbiología , Proteínas Fúngicas/metabolismo , Cromatografía de Gases y Espectrometría de Masas , Regulación Fúngica de la Expresión Génica/efectos de los fármacos , Geotrichum/genética , Geotrichum/metabolismo , Mentha piperita , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control
7.
FEBS Open Bio ; 9(1): 18-25, 2019 01.
Artículo en Inglés | MEDLINE | ID: mdl-30652070

RESUMEN

Soft cheese with white rind lacks essential fatty acids (EFAs), and as a result its long-term consumption may lead to various kinds of cardiovascular and cerebrovascular diseases, such as hyperlipidemia, hypertension, and atherosclerosis. Geotrichum candidum is a dimorphic yeast that plays an important role in the ripening of mold cheese. A gene coding for Δ12 fatty acid desaturase, a critical bifunctional enzyme desaturating oleic acid (OA) and linoleic acid (LA) to produce LA and α-linolenic acid (ALA), respectively, was isolated from G. candidum, and then cloned and heterologously expressed in Saccharomyces cerevisiae. This gene, named GcFADS12, had an open reading frame of 1257 bp and codes for a protein of 419 amino acids with a predicted molecular mass of 47.5 kDa. Characterization showed that GcFADS12 had the ability to convert OA to LA and LA to ALA, and the conversion rates for OA and LA were 20.40 ± 0.66% and 6.40 ± 0.57%, respectively. We also found that the protein product of GcFADS12 catalyzes the conversion of the intermediate product (LA) to ALA by addition of OA as the sole substrate. The catalytic activity of GcFADS12 on OA and LA was unaffected by fatty acid concentrations. Kinetic analysis revealed that GcFADS12 had stronger affinity for the OA than for the LA substrate. This study offers a solid basis for improving the production of EFAs by G. candidum in cheese.


Asunto(s)
Queso/microbiología , Clonación Molecular , Ácido Graso Desaturasas/genética , Ácido Graso Desaturasas/metabolismo , Geotrichum/enzimología , Geotrichum/genética , Secuencia de Aminoácidos , Filogenia , Alineación de Secuencia
8.
FEMS Yeast Res ; 19(1)2019 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-30295727

RESUMEN

Geotrichum candidum is a fungus-like yeast widely used as a starter culture for cheese ripening for its proteolytic and lipolytic activities and its contribution to the cheese flavours. The sequenced strain G. candidum CLIB 918 was isolated from cheese Pont-L'Evêque. This strain's ability to produce volatile compounds was compared to the ability of a known strong sulphur compound producer G. candidum strain (Gc203). The aminotransferase-coding genes BAT2 and ARO8 were identified to be involved in methionine catabolism. The production of volatile compounds indicated that the sequenced strain was a moderate producer compared to the strong producer strain. The major volatile compounds were produced from sulphur amino acid, branched-chain amino acid and fatty acid metabolisms. Metabolite content of the cells showed that the ability of the strain to produce volatile compounds was inversely proportional to its ability to store amino acids inside the cells. Reduced glutathione, hypotaurine and taurine intracellular concentrations and volatile fatty aldehyde production indicated the role of oxidative stress sensitivity in flavour production. The increase in expression of several genes in a Reblochon-type cheese at the end of ripening confirmed that oxygen and iron were key factors regulating cheese flavour production.


Asunto(s)
Aminoácidos/metabolismo , Aromatizantes/metabolismo , Regulación Fúngica de la Expresión Génica , Geotrichum/genética , Geotrichum/metabolismo , Estrés Oxidativo , Compuestos Orgánicos Volátiles/metabolismo , Queso/microbiología , Geotrichum/aislamiento & purificación , Redes y Vías Metabólicas/genética , Secuenciación Completa del Genoma
9.
Artículo en Inglés | MEDLINE | ID: mdl-29229638

RESUMEN

Saprochaete capitata, formerly known as Geotrichum capitatum, is an emerging fungal pathogen with low susceptibility to echinocandins. Here, we report the nucleotide sequence of the S. capitata hot spot 1 region of the FKS gene (FKS HS1), which codifies for the catalytic subunit of ß-1,3-d-glucan synthase, the target of echinocandins. For that purpose, we first designed degenerated oligonucleotide primers derived from conserved flanking regions of the FKS1 HS1 segment of 12 different fungal species. Interestingly, analysis of the translated FKS HS1 sequences of 12 isolates of S. capitata revealed that all of them exhibited the same F-to-L substitution in a position that is highly related to reduced echinocandin susceptibility.


Asunto(s)
Antifúngicos/farmacología , Farmacorresistencia Fúngica/genética , Equinocandinas/farmacología , Proteínas Fúngicas/genética , Regulación Fúngica de la Expresión Génica , Geotrichum/genética , Glucosiltransferasas/genética , Sustitución de Aminoácidos , Secuencia de Bases , ADN de Hongos/genética , Proteínas Fúngicas/metabolismo , Geotricosis/tratamiento farmacológico , Geotricosis/microbiología , Geotricosis/patología , Geotrichum/efectos de los fármacos , Geotrichum/crecimiento & desarrollo , Geotrichum/aislamiento & purificación , Glucosiltransferasas/metabolismo , Humanos , Pruebas de Sensibilidad Microbiana , Subunidades de Proteína/genética , Subunidades de Proteína/metabolismo , Análisis de Secuencia de ADN
10.
Microb Ecol ; 75(3): 647-661, 2018 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-28894891

RESUMEN

Plant-associated endophytes are recognized as sources of novel bioactive molecules having diverse applications. In this study, an endophytic yeast-like fungal strain was isolated from the fruit of eggplant (Solanum melongena) and identified as Geotrichum candidum through phenotypic and genotypic characterizations. This endophytic G. candidum isolate PF005 was found to emit fruity scented volatiles. The compositional profiling of volatile organic compounds (VOCs) revealed the presence of 3-methyl-1-butanol, ethyl 3-methylbutanoate, 2-phenylethanol, isopentyl acetate, naphthalene, and isobutyl acetate in significant proportion when analyzed on a time-course basis. The VOCs from G. candidum exhibited significant mycelial growth inhibition (54%) of phytopathogen Rhizoctonia solani, besides having mild antifungal activity against a few other fungi. The source of carbon as a nutrient was found to be an important factor for the enhanced biosynthesis of antifungal VOCs. The antifungal activity against phytopathogen R. solani was improved up to 91% by feeding the G. candidum with selective precursors of alcohol and ester volatiles. Furthermore, the antifungal activity of VOCs was enhanced synergistically up to 92% upon the exogenous addition of naphthalene (1.0 mg/plate). This is the first report of G. candidum as an endophyte emitting antifungal VOCs, wherein 2-penylethanol, isopentyl acetate, and naphthalene were identified as important contributors to its antifungal activity. Possible utilization of G. candidum PF005 as a mycofumigant has been discussed based upon its antifungal activity and the qualified presumption of safety status.


Asunto(s)
Antifúngicos/farmacología , Endófitos/metabolismo , Geotrichum/metabolismo , Solanum melongena/microbiología , Compuestos Orgánicos Volátiles/farmacología , Antifúngicos/química , Carbono/metabolismo , Medios de Cultivo/química , ADN de Hongos/genética , Endófitos/genética , Endófitos/crecimiento & desarrollo , Endófitos/aislamiento & purificación , Genotipo , Geotrichum/genética , Geotrichum/crecimiento & desarrollo , Geotrichum/aislamiento & purificación , Pruebas de Sensibilidad Microbiana , Micelio/efectos de los fármacos , Micelio/crecimiento & desarrollo , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control , ARN Ribosómico 18S/genética , Rhizoctonia/efectos de los fármacos , Rhizoctonia/crecimiento & desarrollo , Rhizoctonia/patogenicidad , Compuestos Orgánicos Volátiles/química
11.
Appl Microbiol Biotechnol ; 101(17): 6637-6649, 2017 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-28718057

RESUMEN

Higher alcohols are the byproducts of yeasts in alcohol fermentation and are harmful to human health at high concentrations. In this study, immobilized crude enzymes extracted from Geotrichum spp. strains S12 and S13 were separately employed to treat red wine, then GC and GC-MS analyses were used to determine the profiles of volatile compounds in untreated and treated wine samples. Immobilized enzymes from S13 (SA-S13E) were more active in decreasing higher alcohols than enzymes from S12. Conditions for preparing SA-S13E were optimized, and best results were obtained at a sodium alginate concentration of 35 g/L, calcium chloride of 20 g/L, and crude enzyme dosage of 3 mL. Treatment with SA-S13E significantly increased the ester content and sensory quality of wine. After being reused three times, SA-S13E still exhibited approximately 80% activity towards 1-propanol, isobutanol, and hexanol and had certain activity even after 3 months storage at -20 °C, indicating high stability in application and storage and thus showing potential in wine processing.


Asunto(s)
Enzimas Inmovilizadas/metabolismo , Geotrichum/enzimología , Vino/análisis , Fermentación , Manipulación de Alimentos , Cromatografía de Gases y Espectrometría de Masas , Geotrichum/genética , Geotrichum/metabolismo , Humanos
12.
Mycoses ; 60(4): 273-279, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-28150341

RESUMEN

Saprochaete and Geotrichum spp. are rare emerging fungi causing invasive fungal diseases in immunosuppressed patients and scarce evidence is available for treatment decisions. Among 505 cases of rare IFD from the FungiScope™ registry, we identified 23 cases of invasive infections caused by these fungi reported from 10 countries over a 12-year period. All cases were adults and previous chemotherapy with associated neutropenia was the most common co-morbidity. Fungaemia was confirmed in 14 (61%) cases and deep organ involvement included lungs, liver, spleen, central nervous system and kidneys. Fungi were S. capitata (n=14), S. clavata (n=5), G. candidum (n=2) and Geotrichum spp. (n=2). Susceptibility was tested in 16 (70%) isolates. All S. capitata and S. clavata isolates with the exception of one S. capitata (MIC 4 mg/L) isolate had MICs>32 mg/L for caspofungin. For micafungin and anidulafungin, MICs varied between 0.25 and >32 mg/L. One case was diagnosed postmortem, 22 patients received targeted treatment, with voriconazole as the most frequent first line drug. Overall mortality was 65% (n=15). Initial echinocandin treatment was associated with worse outcome at day 30 when compared to treatment with other antifungals (amphotericin B ± flucytosine, voriconazole, fluconazole and itraconazole) (P=.036). Echinocandins are not an option for these infections.


Asunto(s)
Geotricosis/microbiología , Geotrichum/aislamiento & purificación , Infecciones Fúngicas Invasoras/microbiología , Sistema de Registros , Saccharomycetales/aislamiento & purificación , Adolescente , Adulto , Anciano , Anfotericina B/farmacología , Anfotericina B/uso terapéutico , Antifúngicos/farmacología , Antifúngicos/uso terapéutico , Equinocandinas/farmacología , Equinocandinas/uso terapéutico , Femenino , Fluconazol/farmacología , Fluconazol/uso terapéutico , Fungemia/diagnóstico , Fungemia/tratamiento farmacológico , Fungemia/microbiología , Geotricosis/tratamiento farmacológico , Geotricosis/mortalidad , Geotrichum/clasificación , Geotrichum/efectos de los fármacos , Geotrichum/genética , Humanos , Huésped Inmunocomprometido , Infecciones Fúngicas Invasoras/tratamiento farmacológico , Infecciones Fúngicas Invasoras/mortalidad , Lipopéptidos/farmacología , Lipopéptidos/uso terapéutico , Masculino , Micafungina , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Neutropenia/complicaciones , Neutropenia/tratamiento farmacológico , Neutropenia/microbiología , Saccharomycetales/clasificación , Saccharomycetales/efectos de los fármacos , Saccharomycetales/genética , Voriconazol/farmacología , Voriconazol/uso terapéutico , Adulto Joven
13.
Yeast ; 34(4): 165-178, 2017 04.
Artículo en Inglés | MEDLINE | ID: mdl-27862252

RESUMEN

Geotrichum candidum is a ubiquitous yeast and an essential component in the production of many soft cheeses. We developed a multilocus sequence typing (MLST) scheme with five retained loci (NUP116, URA1, URA3, SAPT4 and PLB3) which were sufficiently divergent to distinguish 40 sequence types (STs) among the 67 G. candidum strains tested. Phylogenetic analyses defined five main clades; one clade was restricted to environmental isolates, three other clades included distinct environmental isolates and dairy strains, while the fifth clade comprised 34 strains (13 STs), among which all but two were isolated from milk, cheese or the dairy environment. These findings suggest an adaptation to the dairy ecosystems by a group of specialized European G. candidum strains. In addition, we developed a polymerase chain reaction inter-long terminal repeat scheme, a fast and reproducible random amplification of polymorphic DNA-like method for G. candidum, to type the closely related dairy strains, which could not be distinguished by MLST. Overall, our findings distinguished two types of dairy strains, one forming a homogeneous group with little genetic diversity, and the other more closely related to environmental isolates. Neither regional nor cheese specificity was observed in the dairy G. candidum strains analysed. This present study sheds light on the genetic diversity of both dairy and environmental strains of G. candidum and thus extends previous characterizations that have focused on the cheese isolates of this species. Copyright © 2016 John Wiley & Sons, Ltd.


Asunto(s)
ADN de Hongos/genética , Variación Genética , Geotrichum/genética , Tipificación de Secuencias Multilocus , Filogenia , Técnicas de Tipificación Micológica , Análisis de Secuencia de ADN
14.
Sci Rep ; 5: 11571, 2015 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-26108467

RESUMEN

The evolutionary history of the characters underlying the adaptation of microorganisms to food and biotechnological uses is poorly understood. We undertook comparative genomics to investigate evolutionary relationships of the dairy yeast Geotrichum candidum within Saccharomycotina. Surprisingly, a remarkable proportion of genes showed discordant phylogenies, clustering with the filamentous fungus subphylum (Pezizomycotina), rather than the yeast subphylum (Saccharomycotina), of the Ascomycota. These genes appear not to be the result of Horizontal Gene Transfer (HGT), but to have been specifically retained by G. candidum after the filamentous fungi-yeasts split concomitant with the yeasts' genome contraction. We refer to these genes as SRAGs (Specifically Retained Ancestral Genes), having been lost by all or nearly all other yeasts, and thus contributing to the phenotypic specificity of lineages. SRAG functions include lipases consistent with a role in cheese making and novel endoglucanases associated with degradation of plant material. Similar gene retention was observed in three other distantly related yeasts representative of this ecologically diverse subphylum. The phenomenon thus appears to be widespread in the Saccharomycotina and argues that, alongside neo-functionalization following gene duplication and HGT, specific gene retention must be recognized as an important mechanism for generation of biodiversity and adaptation in yeasts.


Asunto(s)
Adaptación Fisiológica/genética , Evolución Molecular , Genes Fúngicos/genética , Variación Genética , Geotrichum/genética , Levaduras/genética , Biodiversidad , ADN de Hongos/química , ADN de Hongos/genética , Proteínas Fúngicas/genética , Transferencia de Gen Horizontal , Genoma Fúngico/genética , Genoma Mitocondrial/genética , Geotrichum/crecimiento & desarrollo , Datos de Secuencia Molecular , Filogenia , Análisis de Secuencia de ADN , Especificidad de la Especie , Levaduras/clasificación , Levaduras/crecimiento & desarrollo
15.
Int J Food Microbiol ; 194: 54-61, 2015 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-25461609

RESUMEN

Cheese ripening involves the activity of various bacteria, yeasts or molds, which contribute to the development of the typical color, flavor and texture of the final product. In situ measurements of gene expression are increasingly being used to improve our understanding of the microbial flora activity in cheeses. The objective of the present study was to investigate the physiology and metabolic activity of Geotrichum candidum during the ripening of Reblochon-type cheeses by quantifying mRNA transcripts at various ripening times. The expression of 80 genes involved in various functions could be quantified with a correct level of biological repeatability using a set of three stable reference genes. As ripening progresses, a decrease in expression was observed for genes involved in cell wall organization, translation, vesicular mediated transport, and in cytoskeleton constituents and ribosomal protein genes. There was also a decrease in the expression of mitochondrial F1F0 ATP synthase and plasma membrane H(+) ATPase genes. Some genes involved in the catabolism of lactate, acetate and ethanol were expressed to a greater extent at the beginning of ripening. During the second part of ripening, there was an increased expression of genes involved in the transport and catabolism of amino acids, which could be attributed to a change in the energy source. There was also an increase in the expression of genes involved in autophagy and of genes possibly involved in lifespan determination. Quantification of mRNA transcripts may also be used to produce bioindicators relevant for cheesemaking, for example when considering genes encoding enzymes involved in the catabolism of amino acids.


Asunto(s)
Queso/microbiología , Microbiología de Alimentos , Regulación Fúngica de la Expresión Génica , Geotrichum/genética , Perfilación de la Expresión Génica , Genes Fúngicos/genética , Geotrichum/metabolismo
16.
Mycopathologia ; 177(5-6): 319-24, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24748454

RESUMEN

Invasive Geotrichum clavatum fungal infections are extremely rare and unusual, occurring nearly exclusively in patients experiencing prolonged neutropenia during the treatment for acute myeloid leukaemia. Several groups of cases of fatal G. clavatum infection were reported in France between 2011 and 2012, but the ecological niche has not yet been identified. We report a case of a 32-year-old patient with acute myeloid leukaemia who developed G. clavatum sepsis with primary peritonitis, hepatic nodular lesions, and multivisceral failure during aplasia after induction followed by salvage chemotherapy. He was treated with voriconazole and is still alive 1 year after with controlled disease. We then discuss the epidemiological, clinical, and therapeutic features of these serious fungal infections compared to the published data.


Asunto(s)
Geotricosis/etiología , Geotrichum/aislamiento & purificación , Leucemia Mieloide Aguda/complicaciones , Adulto , Antifúngicos/uso terapéutico , Geotricosis/tratamiento farmacológico , Geotricosis/microbiología , Geotrichum/genética , Geotrichum/fisiología , Humanos , Masculino , Voriconazol/uso terapéutico
17.
BMC Genomics ; 15: 235, 2014 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-24670012

RESUMEN

BACKGROUND: Camembert-type cheese ripening is driven mainly by fungal microflora including Geotrichum candidum and Penicillium camemberti. These species are major contributors to the texture and flavour of typical bloomy rind cheeses. Biochemical studies showed that G. candidum reduces bitterness, enhances sulphur flavors through amino acid catabolism and has an impact on rind texture, firmness and thickness, while P. camemberti is responsible for the white and bloomy aspect of the rind, and produces enzymes involved in proteolysis and lipolysis activities. However, very little is known about the genetic determinants that code for these activities and their expression profile over time during the ripening process. RESULTS: The metatranscriptome of an industrial Canadian Camembert-type cheese was studied at seven different sampling days over 77 days of ripening. A database called CamemBank01 was generated, containing a total of 1,060,019 sequence tags (reads) assembled in 7916 contigs. Sequence analysis revealed that 57% of the contigs could be affiliated to molds, 16% originated from yeasts, and 27% could not be identified. According to the functional annotation performed, the predominant processes during Camembert ripening include gene expression, energy-, carbohydrate-, organic acid-, lipid- and protein- metabolic processes, cell growth, and response to different stresses. Relative expression data showed that these functions occurred mostly in the first two weeks of the ripening period. CONCLUSIONS: These data provide further advances in our knowledge about the biological activities of the dominant ripening microflora of Camembert cheese and will help select biological markers to improve cheese quality assessment.


Asunto(s)
Queso/microbiología , Geotrichum/genética , Penicillium/genética , Mapeo Contig , Bases de Datos Genéticas , Etiquetas de Secuencia Expresada , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Perfilación de la Expresión Génica , Geotrichum/aislamiento & purificación , Penicillium/aislamiento & purificación , Análisis de Secuencia de ADN , Azufre/metabolismo , Transcriptoma
18.
Artículo en Inglés | MEDLINE | ID: mdl-24316824

RESUMEN

Here, a 1.82 Šresolution X-ray structure of a glycoside hydrolase family 74 (GH74) enzyme from Acidothermus cellulolyticus is reported. The resulting structure was refined to an R factor of 0.150 and an Rfree of 0.196. Structural analysis shows that five related structures have been reported with a secondary-structure similarity of between 75 and 89%. The five similar structures were all either Clostridium thermocellum or Geotrichum sp. M128 GH74 xyloglucanases. Structural analysis indicates that the A. cellulolyticus GH74 enzyme is an endoxyloglucanase, as it lacks a characteristic loop that blocks one end of the active site in exoxyloglucanases. Superimposition with the C. thermocellum GH74 shows that Asp451 and Asp38 are the catalytic residues.


Asunto(s)
Actinomycetales/química , Proteínas Bacterianas/química , Glicósido Hidrolasas/química , Modelos Moleculares , Actinomycetales/enzimología , Actinomycetales/genética , Secuencia de Aminoácidos , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Clostridium thermocellum/química , Clostridium thermocellum/enzimología , Clostridium thermocellum/genética , Cristalografía por Rayos X , Escherichia coli/genética , Escherichia coli/metabolismo , Expresión Génica , Geotrichum/química , Geotrichum/enzimología , Geotrichum/genética , Glicósido Hidrolasas/genética , Glicósido Hidrolasas/metabolismo , Datos de Secuencia Molecular , Dominios y Motivos de Interacción de Proteínas , Estructura Secundaria de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Alineación de Secuencia , Homología Estructural de Proteína
19.
J Dairy Sci ; 96(12): 7692-7, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24119798

RESUMEN

This study reports a rapid PCR-based technique using a one-enzyme RFLP for discrimination of yeasts isolated from bovine clinical and subclinical mastitis milk samples. We analyzed a total of 1,486 milk samples collected over 1 yr in south Sardinia and northern Italy, and 142 yeast strains were preliminarily grouped based on their cultural morphology and physiological characteristics. Assimilation tests were conducted using the identification kit API ID 32C and APILAB Plus software (bioMérieux, Marcy l'Etoile, France). For PCR-RFLP analysis, the 18S-ITS1-5.8S ribosomal(r)DNA region was amplified and then digested with HaeIII, and dendrogram analysis of RFLP fragments was carried out. Furthermore, within each of the groups identified by the API or PCR-RFLP methods, the identification of isolates was confirmed by sequencing of the D1/D2 region using an ABI Prism 310 automatic sequencer (Applied Biosystems, Foster City, CA). The combined phenotypic and molecular approach enabled the identification of 17 yeast species belonging to the genera Candida (47.9%), Cryptococcus (21.1%), Trichosporon (19.7%), Geotrichum (7.1%), and Rhodotorula (4.2%). All Candida species were correctly identified by the API test and their identification confirmed by sequencing. All strains identified with the API system as Geotrichum candidum, Cryptococcus uniguttulatus, and Rhodotorula glutinis also produced characteristic restriction patterns and were confirmed as Galactomyces geotrichum (a teleomorph of G. candidum), Filobasidium uniguttulatum (teleomorph of Crypt. uniguttulatus), and R. glutinis, respectively, by D1/D2 rDNA sequencing. With regard to the genus Trichosporon, preliminary identification by API was problematic, whereas the RFLP technique used in this study gave characteristic restriction profiles for each species. Moreover, sequencing of the D1/D2 region allowed not only successful identification of Trichosporon gracile where API could not, but also correct identification of misidentified isolates. In conclusion, the 18S-ITS1-5.8S region appears to be useful in detecting genetic variability among yeast species, which is valuable for taxonomic purposes and for species identification. We have established an RFLP database for yeast species identified in milk samples using the software GelCompar II and the RFLP database constitutes an initial method for veterinary yeast identification.


Asunto(s)
Mastitis Bovina/microbiología , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción , Levaduras/aislamiento & purificación , Animales , Secuencia de Bases , Candida/clasificación , Candida/genética , Bovinos , Cryptococcus/clasificación , Cryptococcus/genética , ADN de Hongos/química , ADN Ribosómico/análisis , ADN Ribosómico/genética , Femenino , Francia , Geotrichum/clasificación , Geotrichum/genética , Italia , Leche/microbiología , Rhodotorula/clasificación , Rhodotorula/genética , Saccharomyces cerevisiae/clasificación , Saccharomyces cerevisiae/genética , Análisis de Secuencia de ADN , Trichosporon/clasificación , Trichosporon/genética , Levaduras/clasificación , Levaduras/genética
20.
Food Microbiol ; 36(2): 481-7, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24010632

RESUMEN

The aim of this work was the genetic characterization at the strain level of 39 presumed Geotrichum candidum isolates isolated throughout the artisanal manufacturing and ripening of Armada cheese and tentatively identified at genus and/or species level by phenotypic characteristics. The molecular identification of the strains included among others the amplification and sequencing of the D1/D2 domains of the 26S rRNA gene. A restriction fragment length polymorphism (RFLP) analysis with the ITS1-5.8S-ITS2 PCR amplicons and a randomly amplified polymorphic DNA (RAPD) analysis with five different primers were carried out. The bands pattern profile obtained through RFLP by enzymatic restriction with HinfI was the same for all the strains studied, which confirmed the classification of the strains at species level. A RAPD-PCR analysis with three different primers was applied to assess the intraspecific diversity, in this way 16 band profiles were obtained for the 39 strains studied by the combined use of primers Ari1 and Omt1. This study contributes to know the occurrence and genotypic biodiversity of G. candidum in Armada cheese.


Asunto(s)
Queso/microbiología , Geotrichum/genética , Geotrichum/aislamiento & purificación , Leche/microbiología , Animales , Bovinos , ADN de Hongos/genética , Variación Genética , Geotrichum/clasificación , Datos de Secuencia Molecular , Filogenia , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción
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