RESUMO
Iron deficiency anemia (IDA) and cystoisosporosis are the most common clinical conditions of fast-growing piglets. Until now, IDA and cystoisosporosis have been managed by intramuscular injection of iron complexes (such as dextran or gleptoferron) and oral administration of toltrazuril. Recently, a new combination product containing toltrazuril and gleptoferron for intramuscular application (Forceris®) has been registered. The objective of this study was to compare the pharmacokinetic profiles of toltrazuril and its main metabolite, toltrazuril sulfone, following a single oral (Baycox®) or intramuscular (Forceris®, a toltrazuril-iron combination product) administration at 20 mg/kg to young suckling piglets. The orally treated piglets were also supplemented with iron (Gleptosil®), and the hematinic activities were compared. Piglets in both groups received comparable doses. The peak concentration (Cmax) of toltrazuril after intramuscular administration was 11% lower than that after oral administration (p = .376). However, the exposure to toltrazuril (AUC) was significantly increased (40% higher) when toltrazuril was administered intramuscularly (p = .036). The Cmax and AUC values of the active metabolite, toltrazuril sulfone were 39% and 34% higher, respectively, after intramuscular administration (p = .007 and 0.008, respectively). Piglets in both groups were properly protected against IDA. In conclusion, a higher relative bioavailability of toltrazuril is observed when toltrazuril is administered intramuscularly.
RESUMO
More precise identification and treatment monitoring of prediabetic/diabetic individuals will require additional biomarkers to complement existing diagnostic tests. Candidates include hyperglycemia-induced adducts such as advanced glycation end products (AGEs) of proteins, lipids, and DNA. The potential for DNA-AGEs as diabetic biomarkers was examined in a longitudinal study using the Leprdb/db animal model of metabolic syndrome. The DNA-AGE, N2-(1-carboxyethyl)-2'-deoxyguanosine (CEdG) was quantified by mass spectrometry using isotope dilution from the urine and tissue of hyperglycemic and normoglycemic mice. Hyperglycemic mice (fasting plasma glucose, FPG, ≥ 200 mg/dL) displayed a higher median urinary CEdG value (238.4 ± 112.8 pmol/24 h) than normoglycemic mice (16.1 ± 11.8 pmol/24 h). Logistic regression analysis revealed urinary CEdG to be an independent predictor of hyperglycemia. Urinary CEdG was positively correlated with FPG in hyperglycemic animals and with HbA1c for all mice. Average tissue-derived CEdG was also higher in hyperglycemic mice (18.4 CEdG/106 dG) than normoglycemic mice (4.4 CEdG/106 dG). Urinary CEdG was significantly elevated in Leprdb/db mice relative to Leprwt/wt, and tissue CEdG values increased in the order Leprwt/wt < Leprwt/db < Leprdb/db. These data suggest that urinary CEdG measurement may provide a noninvasive quantitative index of glycemic status and augment existing biomarkers for the diagnosis and monitoring of diabetes.
Assuntos
DNA/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Modelos Animais de Doenças , Produtos Finais de Glicação Avançada/metabolismo , Animais , Camundongos , Camundongos Endogâmicos C57BLRESUMO
The 2-oxoglutarate-dependent iron enzyme ALKBH3 is an antitumor target and a potential diagnostic marker for several tumor types, including prostate cancer. However, there is at present no simple way to measure this enzyme's activity. Here we describe a fluorogenic probe design (MAQ) that is directly responsive to ALKBH3 repair activity. It makes use of the fluorescence-quenching properties of 1-methyladenine; removal of the alkyl group results in a >10-fold light-up signal. The probe is specific for ALKBH3 over its related homologue ALKBH2 and can be used to identify and measure the effectiveness of enzyme inhibitors. Measurements of the enzyme substrate parameters show that MAQ displays Km and kcat values essentially the same as those of the native substrate. Finally, we show that the probe functions efficiently in cells, allowing imaging and quantitation of ALKBH3 activity by microscopy and flow cytometry. We expect that MAQ probes will be broadly useful in the study of the basic biology of ALKBH3 and in clinical cancer applications as well.
Assuntos
Homólogo AlkB 3 da Dioxigenase Dependente de alfa-Cetoglutarato/análise , Biomarcadores Tumorais/análise , Dano ao DNA , Corantes Fluorescentes/química , Neoplasias da Próstata/enzimologia , Adenina/análogos & derivados , Adenina/análise , Adenina/química , Adenina/metabolismo , Homólogo AlkB 3 da Dioxigenase Dependente de alfa-Cetoglutarato/química , Homólogo AlkB 3 da Dioxigenase Dependente de alfa-Cetoglutarato/metabolismo , Animais , Antineoplásicos Alquilantes/farmacologia , Biomarcadores Tumorais/metabolismo , Corantes Fluorescentes/análise , Corantes Fluorescentes/síntese química , Humanos , Cinética , Masculino , Camundongos , Oxirredução , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/genética , Espectrometria de FluorescênciaRESUMO
BACKGROUND: The objective of the work was to characterize fungal endophytes from aerial parts of Vanilla planifolia. Also, to establish their biotransformation abilities of flavor-related metabolites. This was done in order to find a potential role of endophytes on vanilla flavors. RESULTS: Twenty three MOTUs were obtained, representing 6 fungal classes. Fungi from green pods were cultured on mature green pod based media for 30 days followed by (1)H NMR and HPLC-DAD analysis. All fungi from pods consumed metabolized vanilla flavor phenolics. Though Fusarium proliferatum was recovered more often (37.6% of the isolates), it is Pestalotiopsis microspora (3.0%) that increased the absolute amounts (quantified by (1)H NMR in µmol/g DW green pods) of vanillin (37.0 × 10(-3)), vanillyl alcohol (100.0 × 10(-3)), vanillic acid (9.2 × 10(-3)) and p-hydroxybenzoic acid (87.9 × 10(-3)) by significant amounts. CONCLUSIONS: All plants studied contained endophytic fungi and the isolation of the endophytes was conducted from plant organs at nine sites in Réunion Island including under shade house and undergrowth conditions. Endophytic variation occured between cultivation practices and the type of organ. Given the physical proximity of fungi inside pods, endophytic biotransformation may contribute to the complexity of vanilla flavors.
Assuntos
Endófitos/isolamento & purificação , Fungos/isolamento & purificação , Vanilla/microbiologia , Biodiversidade , Biotransformação/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Análise por Conglomerados , Meios de Cultura/farmacologia , Geografia , Metaboloma/efeitos dos fármacos , Dados de Sequência Molecular , Odorantes , Especificidade de Órgãos/efeitos dos fármacos , Filogenia , Análise de Componente Principal , Espectroscopia de Prótons por Ressonância Magnética , Reunião , Vanilla/efeitos dos fármacosRESUMO
PCSK9 promotes the lysosomal degradation of cell surface LDL receptor (LDLR). We analyzed how excess LDLR generated by PCSK9 deficiency is differently handled in male and female mice to possibly unveil the mechanism leading to the lower efficacy of PCSK9 mAb on LDL-cholesterol levels in women. Analysis of intact or ovariectomized PCSK9 knockout (KO) mice supplemented with placebo or 17ß-estradiol (E2) demonstrated that female, but not male mice massively shed the soluble ectodomain of the LDLR in the plasma. Liver-specific PCSK9 KO or alirocumab-treated WT mice exhibit the same pattern. This shedding is distinct from the basal one and is inhibited by ZLDI-8, a metalloprotease inhibitor pointing at ADAM10/ADAM17. In PCSK9 KO female mice, ZLDI-8 raises by 80â¯% the LDLR liver content in a few hours. This specific shedding is likely cholesterol-dependent: it is prevented in PCSK9 KO male mice that exhibit low intra-hepatic cholesterol levels without activating SREBP-2, and enhanced by mevalonate or high cholesterol feeding, or by E2 known to stimulate cholesterol synthesis via the estrogen receptor-α. Liver transcriptomics demonstrates that critically low liver cholesterol in ovariectomized female or knockout male mice also hampers the cholesterol-dependent G2/M transition of the cell cycle. Finally, higher levels of shed LDLR were measured in the plasma of women treated with PCSK9 mAb. PCSK9 knockout female mice hormonally sustain cholesterol synthesis and shed excess LDLR, seemingly like women. In contrast, male mice rely on high surface LDLR to replenish their stocks, despite 80â¯% lower circulating LDL.
Assuntos
Ácido Mevalônico , Pró-Proteína Convertase 9 , Animais , Colesterol/metabolismo , Estradiol/metabolismo , Estradiol/farmacologia , Feminino , Fígado/metabolismo , Metaloproteases/metabolismo , Ácido Mevalônico/metabolismo , Camundongos , Camundongos Knockout , Pró-Proteína Convertase 9/metabolismo , Receptores de Superfície Celular , Receptores de Estrogênio , Receptores de LDL/genética , Receptores de LDL/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismoRESUMO
Somatic mutation theory explains how DNA damage can lead to the malignant transformation of cells. It therefore elucidates the connection between genotoxic agents and cancers. Mutational spectra, which tend to be characteristic of a cancer type, are available for certain genes like p53 which is frequently mutated in tumors. A mutational spectrum could therefore be the signature of the genotoxic agent(s) at the origin of the malignant transformation. Ligation-mediated PCR (LMPCR) is a genomic sequencing method that can be used for the mapping of DNA damage at nucleotide resolution. Such a mapping can then be compared to a mutational spectrum to test the hypothesis that implies one agent can cause mutations into one cancer type. LMPCR has been used this way to map DNA damage generated by different UV wavelengths. The frequently damaged sites following UVB irradiation correlate with the mutational spectrum of p53 in skin cancer. Similarly, BPDE, the activated form of the benzo[a]pyrene present in tobacco smoke, generates frequent adducts at sites corresponding to mutation hotspots of p53 in lung cancers. Still, the correlation between BPDE damage sites and p53 mutations is not perfect and this suggests a role of other genotoxic substances that are also present in tobacco smoke, such as the nitrosamine NNK. Finally, and beyond this objective of better understanding somatic mutagenesis, LMPCR is commonly used whenever DNA damage frequency and/or repair is to be investigated.
Assuntos
Transformação Celular Neoplásica/genética , Dano ao DNA , Mutagênese , 7,8-Di-Hidro-7,8-Di-Hidroxibenzo(a)pireno 9,10-óxido/efeitos adversos , Aflatoxina B1/efeitos adversos , Animais , Carcinógenos/toxicidade , Carcinoma Hepatocelular/induzido quimicamente , Códon/efeitos dos fármacos , Códon/efeitos da radiação , DNA/efeitos dos fármacos , DNA/efeitos da radiação , Metilação de DNA , Reparo do DNA , Genes p53 , Humanos , Neoplasias Hepáticas/induzido quimicamente , Neoplasias Pulmonares/etiologia , Neoplasias Pulmonares/genética , Neoplasias Induzidas por Radiação/etiologia , Neoplasias Induzidas por Radiação/genética , Reação em Cadeia da Polimerase/métodos , Neoplasias Cutâneas/etiologia , Neoplasias Cutâneas/genética , Luz Solar/efeitos adversos , Raios Ultravioleta/efeitos adversosRESUMO
The ultraviolet (UV) component of sunlight is the main cause of skin cancer. More than 50% of all non-melanoma skin cancers and >90% of squamous cell carcinomas in the US carry a sunlight-induced mutation in the p53 tumor suppressor gene. These mutations have a strong tendency to occur at methylated cytosines. Ligation-mediated PCR (LMPCR) was used to compare at nucleotide resolution DNA photoproduct formation at dipyrimidine sites either containing or lacking a methylated cytosine. For this purpose, we exploited the fact that the X chromosome is methylated in females only on the inactive X chromosome, and that the FMR1 (fragile-X mental retardation 1) gene is methylated only in fragile-X syndrome male patients. Purified genomic DNA was irradiated with UVC (254nm), UVB (290-320nm) or monochromatic UVB (302 and 313nm) to determine the effect of different wavelengths on cyclobutane pyrimidine dimer (CPD) formation along the X-linked PGK1 (phosphoglycerate kinase 1) and FMR1 genes. We show that constitutive methylation of cytosine increases the frequency of UVB-induced CPD formation by 1.7-fold, confirming that methylation per se is influencing the probability of damage formation. This was true for both UVB sources used, either broadband or monochromatic, but not for UVC. Our data prove unequivocally that following UVB exposure methylated cytosines are significantly more susceptible to CPD formation compared with unmethylated cytosines.
Assuntos
Citosina/metabolismo , Metilação de DNA/efeitos da radiação , Dímeros de Pirimidina/metabolismo , Dímeros de Pirimidina/efeitos da radiação , Raios Ultravioleta/efeitos adversos , Sequência de Bases , Células Cultivadas , Cromossomos Humanos X/metabolismo , Cromossomos Humanos X/efeitos da radiação , Dano ao DNA , Primers do DNA/genética , Feminino , Proteína do X Frágil da Deficiência Intelectual/genética , Síndrome do Cromossomo X Frágil/genética , Síndrome do Cromossomo X Frágil/metabolismo , Humanos , Masculino , Fosfoglicerato Quinase/genética , Inativação do Cromossomo X/genéticaRESUMO
Filamentous fungi asymptomatically colonize the inner tissues of macroalgae, yet their ecological roles remain largely underexplored. Here, we tested if metabolites produced by fungal endophytes might protect their host against a phylogenetically broad spectrum of protistan pathogens. Accordingly, the cultivable fungal endophytes of four brown algal species were isolated and identified based on LSU and SSU sequencing. The fungal metabolomes were tested for their ability to reduce the infection by protistan pathogens in the algal model Ectocarpus siliculosus. The most active metabolomes effective against the oomycetes Eurychasma dicksonii and Anisolpidium ectocarpii, and the phytomixid Maullinia ectocarpii were further characterized chemically. Several pyrenocines isolated from Phaeosphaeria sp. AN596H efficiently inhibited the infection by all abovementioned pathogens. Strikingly, these compounds also inhibited the infection of nori (Pyropia yezoensis) against its two most devastating oomycete pathogens, Olpidiopsis pyropiae, and Pythium porphyrae. We thus demonstrate that fungal endophytes associated with brown algae produce bioactive metabolites which might confer protection against pathogen infection. These results highlight the potential of metabolites to finely-tune the outcome of molecular interactions between algae, their endophytes, and protistan pathogens. This also provide proof-of-concept toward the applicability of such metabolites in marine aquaculture to control otherwise untreatable diseases.
RESUMO
The comet assay is sensitive and can detect DNA damage frequencies less than 1 in 10(7) bases. We have previously shown that several types of DNA damage associated with 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a tobacco-specific pro-mutagen, can be investigated with some specificity using this technique. Little is known about their repair. We verified the ability of the comet assay to quantify the repair kinetics of specific types of damage in normal fibroblasts, e.g., dimethylsulfate-induced 7-methylguanines (7-mG) and UVB-induced cyclobutane pyrimidine dimers. The time course, formation and repair, of DNA damage after acute doses of NNK reactive metabolites, were then compared in normal human cells (fibroblasts and lymphocytes) and in cells proficient for activating NNK (U937 and NCI-H23). NNK can be activated in cells into reactive metabolites that can either methylate or pyridyloxobutylate DNA. The 7-mG generated by methylation gave post-treatment patterns that were sufficiently different between cell types to conclude that repair of 7-mG in U937 cells was fast, repair in lymphocytes was slow, and repair in NCI-H23 cells and fibroblasts displayed intermediate rates. Pyridyloxobutylation generated formamidopyrimidine (fapy) glycosylase (fpg)-sensitive sites that could be the fapy form of 7-pyridyloxobutylguanines produced in cells. For this type of adducts, the post-treatment patterns of adduct frequency as a function of time depended even more clearly on the cell type: fibroblasts and NCI-H23 cells showed an initial rapid increase in fpg-sensitive damage frequency that did not occur in lymphocytes and U937 cells. This increase seemed associated with p53 proficiency in fibroblasts. Our results show that repair kinetics can be investigated with the comet assay and that differences between cell types can be observed with that technique. But it seems that pro-mutagen activation and/or the way a type of adducts is formed can affect the quantification of the repair.
Assuntos
Dano ao DNA , Reparo do DNA , Mutagênicos/toxicidade , Nitrosaminas/toxicidade , Biotransformação , Linhagem Celular , Cromatina/efeitos dos fármacos , Ensaio Cometa , Adutos de DNA/metabolismo , DNA-Formamidopirimidina Glicosilase/metabolismo , Humanos , Cinética , Mutagênicos/química , Mutagênicos/farmacocinética , Nitrosaminas/química , Nitrosaminas/farmacocinética , Proteína Supressora de Tumor p53/metabolismo , Células U937RESUMO
A major fungal invasion was discovered in the prehistoric painted cave of Lascaux in France in Sep 2001. At least three species of the Fusarium solani complex were isolated and identified with a portion of the translation elongation factor 1alpha gene (EF-1alpha), a portion of the nuclear large subunit rDNA (LSU) and nuclear ribosomal intergenic spacer region (ITS). This study represents the first time that Fusarium species have been reported from a cave containing prehistoric paintings. Significant interspecific molecular variability was observed, suggesting that there might have been repeated introduction of the species, possibly carried by water from soils above the cave.
Assuntos
Arqueologia , Fusarium/classificação , Fusarium/isolamento & purificação , Pinturas , DNA Fúngico/análise , DNA Fúngico/isolamento & purificação , DNA Espaçador Ribossômico/análise , França , Fusarium/genética , Dados de Sequência Molecular , Fator 1 de Elongação de Peptídeos/genética , Filogenia , Análise de Sequência de DNARESUMO
Patients who undergo autologous hematopoietic stem cell transplantation (aHCT) for treatment of a relapsed or refractory lymphoma are at risk of developing therapy related- myelodysplasia/acute myeloid leukemia (t-MDS/AML). Part of the risk likely resides in inherent interindividual differences in their DNA repair capacity (DRC), which is thought to influence the effect chemotherapeutic treatments have on the patient's stem cells prior to aHCT. Measuring DRC involves identifying small differences in repair proficiency among individuals. Initially, we investigated the cell model in healthy individuals (primary lymphocytes and/or lymphoblastoid cell lines) that would be appropriate to measure genetically determined DRC using host-cell reactivation assays. We present evidence that interindividual differences in DRC double-strand break repair (by non-homologous end-joining [NHEJ] or single-strand annealing [SSA]) are better preserved in non-induced primary lymphocytes. In contrast, lymphocytes induced to proliferate are required to assay base excision (BER) or nucleotide excision repair (NER). We established that both NHEJ and SSA DRCs in lymphocytes of healthy individuals were inversely correlated with the age of the donor, indicating that DSB repair in lymphocytes is likely not a constant feature but rather something that decreases with age (~0.37% NHEJ DRC/year). To investigate the predictive value of pre-aHCT DRC on outcome in patients, we then applied the optimized assays to the analysis of primary lymphocytes from lymphoma patients and found that individuals who later developed t-MDS/AML (cases) were indistinguishable in their DRC from controls who never developed t-MDS/AML. However, when DRC was investigated shortly after aHCT in the same individuals (21.6 months later on average), aHCT patients (both cases and controls) showed a significant decrease in DSB repair measurements. The average decrease of 6.9% in NHEJ DRC observed among aHCT patients was much higher than the 0.65% predicted for such a short time frame, based on ageing results for healthy individuals.
Assuntos
Reparo do DNA/genética , Transplante de Células-Tronco Hematopoéticas , Doença de Hodgkin/genética , Linfócitos/metabolismo , Linfoma não Hodgkin/genética , Adolescente , Adulto , Idoso , Feminino , Doença de Hodgkin/patologia , Doença de Hodgkin/terapia , Humanos , Linfócitos/patologia , Linfoma não Hodgkin/patologia , Linfoma não Hodgkin/terapia , Masculino , Pessoa de Meia-Idade , Prognóstico , Transplante Autólogo , Adulto JovemRESUMO
BACKGROUND: Penicillium roqueforti is a filamentous fungus used for making blue cheeses worldwide. It also occurs as a food spoiler and in silage and wood. Previous studies have revealed a strong population genetic structure, with specific traits associated with the different populations. Here, we used a large strain collection from worldwide cheeses published recently to investigate the genetic structure of P. roqueforti. PRINCIPAL FINDINGS: We found a genetic population structure in P. roqueforti that was consistent with previous studies, with two main genetic clusters (W+C+ and W-C-, i.e., with and without horizontal gene transferred regions CheesyTer and Wallaby). In addition, we detected a finer genetic subdivision that corresponded to the environment and to protected designation of origin (PDO), namely the Roquefort PDO. We indeed found evidence for eight genetic clusters, one of the cluster including only strains from other environments than cheeses, and another cluster encompassing only strains from the Roquefort PDO. The W-C- and W+C+ cheese clusters were not the most closely related ones, suggesting that there may have been two independent domestication events of P. roqueforti for making blue cheeses. SIGNIFICANCE: The additional population structure revealed here may be relevant for cheese-makers and for understanding the history of domestication in P. roqueforti.
Assuntos
Queijo/microbiologia , Indústria de Laticínios , Penicillium/genéticaRESUMO
4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is the most lung-specific of the carcinogens present in tobacco smoke. Its bioactivation in cells leads to a small amount of methylation or pyridyloxobutylation DNA damage. Considering its great sensitivity, the comet assay seems a technique of choice to investigate NNK-related damage. Several strategies were used to impart some specificity to the assay: (1) using analogs that produce a limited variety of DNA lesions, as they mimic either the methylation or the pyridyloxobutylation pathway; (2) using cells with different bioactivation abilities; (3) using alkali conversion and/or enzymes specific for cleaving particular classes of damage; (4) using different lysis conditions to convert a specific class of DNA lesions into enzyme-sensitive lesions. We determined that several NNK-associated lesions can be detected with some specificity with the comet assay. For the methylation pathway, they are AP sites and the more frequent formamidopyrimidine (fapy) adducts. These fapy adducts correspond to N7-methylguanines generated in the cells that were ring-opened during the assay by the lysis solution at pH 10. For the pyridyloxobutylation pathway, alkylphosphotriesters and a roughly equal frequency of fapy sites were detected. By analogy to the methylation damage, these fapy adducts are thought to be the ring-opened form of N7-pyridyloxobutylguanines (N7-pobG). N7-pobG are unstable and this constitutes the first indirect demonstration of their formation in cells. But contrary to N7-m-fapy, the lysis time or pH did not influence the frequency of N7-pob-fapy adducts detected, suggesting that they already exist in the cells and are not related to the experimental conditions. These N7-pob-fapy have a strong mutagenic potential and we think that the comet assay, in spite of its limitations, is a good way to study them considering their low frequency and the inherent instability of the adduct from which they originate.
Assuntos
Carcinógenos/toxicidade , Ensaio Cometa/métodos , Adutos de DNA/análise , Nitrosaminas/toxicidade , Carcinógenos/química , DNA/metabolismo , Adutos de DNA/metabolismo , Dano ao DNA , Metilação de DNA , Humanos , Concentração de Íons de Hidrogênio , Nitrosaminas/química , Pirimidinas/análise , Células Tumorais Cultivadas , Células U937RESUMO
The aim of this work was to investigate the diversity of endogenous microbes from wheat (Triticum aestivum) and to study the structure of its microbial communities, with the ultimate goal to provide candidate strains for future evaluation as potential biological control agents against wheat diseases. We sampled plants from two wheat cultivars, Apache and Caphorn, showing different levels of susceptibility to Fusarium head blight, a major disease of wheat, and tested for variation in microbial diversity and assemblages depending on the host cultivar, host organ (aerial organs vs. roots) or host maturity. Fungi and bacteria were isolated using a culture dependent method. Isolates were identified using ribosomal DNA sequencing and we used diversity analysis to study the community composition of microorganisms over space and time. Results indicate great species diversity in wheat, with endophytes and pathogens co-occurring inside plant tissues. Significant differences in microbial communities were observed according to host maturity and host organs but we did not find clear differences between host cultivars. Some species isolated have not yet been reported as wheat endophytes and among all species recovered some might be good candidates as biological control agents, given their known effects toward plant pathogens.
RESUMO
Genetic differentiation occurs when gene flow is prevented, due to reproductive barriers or asexuality. Investigating the early barriers to gene flow is important for understanding the process of speciation. Here, we therefore investigated reproductive isolation between different genetic clusters of the fungus Penicillium roqueforti, used for maturing blue cheeses, and also occurring as food spoiler or in silage. We investigated premating and postmating fertility between and within three genetic clusters (two from cheese and one from other substrates), and we observed sexual structures under scanning electron microscopy. All intercluster types of crosses showed some fertility, suggesting that no intersterility has evolved between domesticated and wild populations despite adaptation to different environments and lack of gene flow. However, much lower fertility was found in crosses within the cheese clusters than within the noncheese cluster, suggesting reduced fertility of cheese strains, which may constitute a barrier to gene flow. Such degeneration may be due to bottlenecks during domestication and/or to the exclusive clonal replication of the strains in industry. This study shows that degeneration has occurred rapidly and independently in two lineages of a domesticated species. Altogether, these results inform on the processes and tempo of degeneration and speciation.
Assuntos
Queijo/microbiologia , Domesticação , Fluxo Gênico , Penicillium/fisiologia , Isolamento Reprodutivo , Adaptação Biológica , Fertilidade , Microscopia Eletrônica de Varredura , Penicillium/genética , Penicillium/ultraestruturaRESUMO
Domestication is an excellent model for studies of adaptation because it involves recent and strong selection on a few, identified traits [1-5]. Few studies have focused on the domestication of fungi, with notable exceptions [6-11], despite their importance to bioindustry [12] and to a general understanding of adaptation in eukaryotes [5]. Penicillium fungi are ubiquitous molds among which two distantly related species have been independently selected for cheese making-P. roqueforti for blue cheeses like Roquefort and P. camemberti for soft cheeses like Camembert. The selected traits include morphology, aromatic profile, lipolytic and proteolytic activities, and ability to grow at low temperatures, in a matrix containing bacterial and fungal competitors [13-15]. By comparing the genomes of ten Penicillium species, we show that adaptation to cheese was associated with multiple recent horizontal transfers of large genomic regions carrying crucial metabolic genes. We identified seven horizontally transferred regions (HTRs) spanning more than 10 kb each, flanked by specific transposable elements, and displaying nearly 100% identity between distant Penicillium species. Two HTRs carried genes with functions involved in the utilization of cheese nutrients or competition and were found nearly identical in multiple strains and species of cheese-associated Penicillium fungi, indicating recent selective sweeps; they were experimentally associated with faster growth and greater competitiveness on cheese and contained genes highly expressed in the early stage of cheese maturation. These findings have industrial and food safety implications and improve our understanding of the processes of adaptation to rapid environmental changes.
Assuntos
Queijo/microbiologia , Fungos/genética , Transferência Genética Horizontal , Adaptação Biológica/fisiologia , DNA Fúngico/metabolismo , Microbiologia de Alimentos , Penicillium/metabolismo , FenótipoRESUMO
Patients who develop therapy-related myelodysplasia/acute myeloid leukemia after autologous-hematopoietic stem cell (aHCT) transplant show lower expression levels of DNA repair genes in their pre-aHCT CD34+ cells. To investigate whether this leads to functional differences in DNA repair abilities measurable in patients, we adapted two plasmid-based host-cell reactivation assays for use in primary lymphocytes. Prior to applying these assays to patients who underwent aHCT, we wanted first to verify whether sample preparation affected repair measurements, as patient samples were simply depleted of erythrocytes (with hetastarch) prior to freezing, which is not the classical way to prepare lymphocytes prior to DNA repair experiments (with a density gradient). We show here that lymphocytes from healthy donors freshly prepared with hetastarch show systematically a higher level of double-strand break repair as compared to when prepared with a density gradient, but that most of this difference disappears after samples were frozen. Several observations points to granulocytes as the source for this effect of sample preparation on repair: 1) removal of granulocytes makes the effect disappear, 2) DSB repair measurements for the same individual correlate to the percentage of granulocytes in the sample and 3) nucleofection in presence of granulocytes increases the level of reactive oxygen species (ROS) in neighboring lymphocytes in a dose-dependent manner (R2 of 0.95). These results indicate that co-purified granulocytes, possibly through the release of ROS at time of transfection, can lead to an enhanced repair in lymphocytes that obfuscates any evaluation of inter individual differences in repair as measured by host-cell reactivation. As a result, hetastarch-prepared samples are likely unsuitable for the assessment of DSB repair in primary cells with that type of assay. Granulocyte contamination that exists after a density gradient preparation, although much more limited, could have similar effects, but might be circumvented by freezing cells prior to analysis.
Assuntos
Quebras de DNA de Cadeia Dupla , Reparo do DNA , Granulócitos/citologia , Linfócitos/citologia , Artefatos , Linhagem Celular , Sobrevivência Celular , DNA Super-Helicoidal/genética , Transplante de Células-Tronco Hematopoéticas , Humanos , Antígenos CD15/metabolismo , Linfócitos/metabolismo , Estresse Oxidativo , Plasmídeos/genética , TransfecçãoRESUMO
While the extent and impact of horizontal transfers in prokaryotes are widely acknowledged, their importance to the eukaryotic kingdom is unclear and thought by many to be anecdotal. Here we report multiple recent transfers of a huge genomic island between Penicillium spp. found in the food environment. Sequencing of the two leading filamentous fungi used in cheese making, P. roqueforti and P. camemberti, and comparison with the penicillin producer P. rubens reveals a 575 kb long genomic island in P. roqueforti--called Wallaby--present as identical fragments at non-homologous loci in P. camemberti and P. rubens. Wallaby is detected in Penicillium collections exclusively in strains from food environments. Wallaby encompasses about 250 predicted genes, some of which are probably involved in competition with microorganisms. The occurrence of multiple recent eukaryotic transfers in the food environment provides strong evidence for the importance of this understudied and probably underestimated phenomenon in eukaryotes.
Assuntos
DNA Fúngico/genética , Transferência Genética Horizontal/genética , Ilhas Genômicas/genética , Penicillium/genética , Sequência de Bases , Queijo , Dados de Sequência MolecularRESUMO
Although endophytes of conifers have been extensively studied, few data are available on Cephalotaxaceae. We examined foliar and stem endophytes of Cephalotaxus harringtonia, within its natural range in Japan and outside its natural range in France to study the effect of geography on endophyte community composition. In Japan, rapidly growing endophytes were dominant and may have masked the real diversity, in comparison to France where most endophytes were growing slowly. Analyses of ITS rDNA revealed 104 different Blast Groups among 554 isolates. Almost no overlap between endophyte assemblages of C. harringtonia from the two countries was observed. It seems that Japanese C. harringtonia trees, which should be well adapted to their native site, would host a specific, endemic endophyte community, while trees that have been introduced recently to a foreign site, in France, should have captured existing cosmopolitan and more generalist taxa. In Japan the majority of xylariaceous taxa, which dominated the communities, were unknown and, although closely related to Asian taxa, may be new to science. Dothideomycetes were more prevalent in France. Locally, urban environment, particularly in Japan, may have introduced some perturbations in the native endophyte community of C. harringtonia, with an abundance of generalist fungi such as Nigrospora and Colletotrichum.
Assuntos
Cephalotaxus/microbiologia , Endófitos/isolamento & purificação , Fungos/isolamento & purificação , Endófitos/classificação , Endófitos/genética , França , Fungos/classificação , Fungos/genética , Geografia , Japão , Dados de Sequência Molecular , Filogenia , Especificidade da EspécieRESUMO
Cheese is made from milk by a succession of microbes (bacteria, yeasts and fungi) that determine the consistency and flavor of the cheese. Apart from the emblematic species, Penicillium camemberti and Penicillium roqueforti, cheese fungi are not well known. Here we present a taxonomic and phylogenetic overview of the most important filamentous cheese Ascomycota based on 133 isolates provided by the producers of cheese and cheese starter cultures and 97 isolates from culture collections. We checked the congruence of different gene genealogies to circumscribe cheese species and our results allow us to propose molecular targets for their identification. To study their phylogenetic affiliation, we used LSU rDNA and showed that cheese fungi are found in two classes, the Eurotiomycetes with Penicillium species (Eurotiales) and Sporendonema casei/Sphaerosporium equinum (Onygenales), and the Sordariomycetes with Scopulariopsis species (Microascales) and Fusarium domesticum (Hypocreales). Some of these fungi, such as, P. camemberti, F. domesticum, Scopulariopsis flava and S. casei, are only known from cheeses and are probably adapted to this particular habitat, which is extremely rich in protein and fat. Other cheese fungi are ubiquitous, such as, P. roqueforti, Scopulariopsis candida and Scopulariopsis fusca.