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INTRODUCTION: The Automated Quantification Algorithm (AQuA) is a rapid and efficient method for targeted NMR-based metabolomics, currently optimised for blood plasma. AQuA quantifies metabolites from 1D-1H NMR spectra based on the height of only one signal per metabolite, which minimises the computational time and workload of the method without compromising the quantification accuracy. OBJECTIVES: To develop a fast and computationally efficient extension of AQuA for quantification of selected metabolites in highly complex samples, with minimal prior sample preparation. In particular, the method should be capable of handling interferences caused by broad background signals. METHODS: An automatic baseline correction function was combined with AQuA into an automated workflow, the extended AQuA, for quantification of metabolites in plant root exudate NMR spectra that contained broad background signals and baseline distortions. The approach was evaluated using simulations as well as a spike-in experiment in which known metabolite amounts were added to a complex sample matrix. RESULTS: The extended AQuA enables accurate quantification of metabolites in 1D-1H NMR spectra with varying complexity. The method is very fast (< 1 s per spectrum) and can be fully automated. CONCLUSIONS: The extended AQuA is an automated quantification method intended for 1D-1H NMR spectra containing broad background signals and baseline distortions. Although the method was developed for plant root exudates, it should be readily applicable to any NMR spectra displaying similar issues as it is purely computational and applied to NMR spectra post-acquisition.
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Algoritmos , Metabolómica , Metabolómica/métodos , Espectroscopía de Protones por Resonancia Magnética , Exudados y Transudados , Raíces de PlantasRESUMEN
Biological control is a promising approach to reduce plant diseases caused by fungal pathogens and ensure high productivity in horticultural production. In the present study, we evaluated the biocontrol potential and underlying mechanisms of the beneficial fungus Aureobasidium pullulans against Botrytis cinerea and Colletotrichum acutatum, casual agents of gray mold and anthracnose diseases in strawberry. Notably, this is the first time that A. pullulans has been tested against C. acutatum in strawberry. A. pullulans strains (AP-30044, AP-30273, AP-53383, and AP-SLU6) showed significant variation in terms of growth and conidia production. An inverse relationship was found between the growth and conidiation rate, suggesting a trade-off between resource allocation for growth and conidial production. Dual plate co-culturing assays showed that mycelial growth of B. cinerea and C. acutatum was reduced by up to 35 and 18%, respectively, when challenged with A. pullulans compared with control treatments. Likewise, culture filtrates of A. pullulans showed varying levels of antifungal activity against B. cinerea and C. acutatum, reducing the mycelial biomass by up to 90 and 72%, respectively. Furthermore, milk powder plate assays showed that A. pullulans produced substantial amounts of extracellular proteases, which are known to degrade fungal cuticle. Ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS) analyses revealed that A. pullulans produced exophilins, liamocins, and free fatty acids known to have antifungal properties. A. pullulans shows high potential for successful biological control of strawberry diseases and discuss opportunities for further optimization of this beneficial fungus.
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Assessing risk, planning for safety and security, and aiding recovery for children subjected to violence in a family setting is a complex process. The aim of the article is to synthesize the current research literature about risks for children subjected to violence in the family and outline an empirical base for a holistic and practically usable model of risk assessments placing the individual child at the center. Such assessments need to recognize four different areas of risk: (1) child safety, i.e., known risk factors for severe and dangerous violence aimed at both adults and children and how they play out in the individual case; (2) the child's response in situations with violence; (3) the child's perspective, especially fear and feelings of powerlessness in situations with violence; (4) developmental risks, e.g., instability in the child's situation and care arrangements, lack of a carer/parent as a "secure base" and "safe haven", the child developing difficulties due to the violence (e.g., PTSD), problems in parents' caring capacities in relation to a child with experiences of, and reactions to, violence, and lack of opportunities for the child to make sense of, and create meaning in relation to, experiences of violence. In addition to the four areas of risk, the article emphasizes the importance of assessing the need for immediate intervention and safety planning in the current situation as regards safety, the child's responses, the child's perspectives, and long-term developmental risks.
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Familia , Violencia , Adulto , Humanos , Cuidadores , Medición de RiesgoRESUMEN
BACKGROUND: Clinicians increasingly serve youths from societal/cultural backgrounds different from their own. This raises questions about how to interpret what such youths report. Rescorla et al. (2019, European Child & Adolescent Psychiatry, 28, 1107) found that much more variance in 72,493 parents' ratings of their offspring's mental health problems was accounted for by individual differences than by societal or cultural differences. Although parents' reports are essential for clinical assessment of their offspring, they reflect parents' perceptions of the offspring. Consequently, clinical assessment also requires self-reports from the offspring themselves. To test effects of individual differences, society, and culture on youths' self-ratings of their problems and strengths, we analyzed Youth Self-Report (YSR) scores for 39,849 11-17 year olds in 38 societies. METHODS: Indigenous researchers obtained YSR self-ratings from population samples of youths in 38 societies representing 10 culture cluster identified in the Global Leadership and Organizational Behavioral Effectiveness study. Hierarchical linear modeling of scores on 17 problem scales and one strengths scale estimated the percent of variance accounted for by individual differences (including measurement error), society, and culture cluster. ANOVAs tested age and gender effects. RESULTS: Averaged across the 17 problem scales, individual differences accounted for 92.5% of variance, societal differences 6.0%, and cultural differences 1.5%. For strengths, individual differences accounted for 83.4% of variance, societal differences 10.1%, and cultural differences 6.5%. Age and gender had very small effects. CONCLUSIONS: Like parents' ratings, youths' self-ratings of problems were affected much more by individual differences than societal/cultural differences. Most variance in self-rated strengths also reflected individual differences, but societal/cultural effects were larger than for problems, suggesting greater influence of social desirability. The clinical significance of individual differences in youths' self-reports should thus not be minimized by societal/cultural differences, which-while important-can be taken into account with appropriate norms, as can gender and age differences.
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Individualidad , Padres , Niño , Adolescente , Humanos , Padres/psicología , AutoinformeRESUMEN
Children's exposure to intimate partner violence (IPV) and child abuse (CA) is strongly related to later psychological problems. Few studies exist on patients in child and adolescent mental health services (CAMHS) who have been singly or doubly exposed to IPV and/or CA. The overall aim of the current study was to compare self-reported psychiatric symptoms, post-trauma impact, and post-traumatic stress disorder (PTSD) diagnoses among CAMHS patients who had been singly or doubly exposed or had reported no family violence (NoFV). We expected to find more severe symptoms in both singly and doubly exposed patients than in the NoFV group and that double exposure was associated with more severe symptoms than single exposure (to IPV or CA). Finally, we expected to find that higher frequencies of exposure to IPV or CA were related to more psychiatric symptoms, greater post-trauma impact, and a higher likelihood of PTSD diagnosis. We compared psychiatric symptoms, post-trauma impact, and PTSD diagnosis in 578 patients aged 9-17 years with NoFV (n = 287), single exposure (n = 162), and double exposure (n = 129). The influence of gender, age, age of onset, frequency, and traumatic interpersonal events outside the family (IPE) were regressed on psychiatric symptoms, post-trauma impact, and PTSD diagnoses. Patients with double exposure had more severe symptoms than the NoFV group, and patients with single exposure had more trauma-related symptoms than the NoFV group. Double exposure was associated with more severe symptoms than single exposure, and frequency (of exposure to IPV and/or CA) and IPE influenced trauma symptoms and psychiatric symptoms, respectively. Exposure to more than one type of violence is associated with more severe symptoms, but other factors such as frequency of violent acts and IPE are important factors to focus on in future studies and clinical assessment.
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Maltrato a los Niños , Violencia Doméstica , Exposición a la Violencia , Violencia de Pareja , Trastornos por Estrés Postraumático , Adolescente , Niño , Maltrato a los Niños/psicología , Violencia Doméstica/psicología , Femenino , Humanos , Violencia de Pareja/psicología , Madres/psicología , Trastornos por Estrés Postraumático/epidemiología , Trastornos por Estrés Postraumático/psicologíaRESUMEN
The fungus Aspergillus amoenus Roberg strain UP197 was shown to produce antibacterial tetramic acid based alkaloids. Two new compounds, pyranterreone I and J (1 and 2), were isolated and characterized, in addition to the known compounds cordylactam, 7-hydroxycordylactam, pyranterreone C, D, F and G. Neither the pyranterreones nor the cordylacctams had previously been tested for antimicrobial activity. Thus, all isolated compounds were tested against a panel of clinically important bacteria and fungi. Pyranterreone C was active against Gram-positive and Gram-negative bacteria, with minimal inhibitory concentrations (MIC) between 1 and 8 µg/mL, whereas the MICs for all other compounds were >32 µg/mL. Pyranoterreone C was cytotoxic towards HepG2 cells, and since pyranterreone C reacted rapidly with the nucleophile cysteine, it is likely that the observed antibacterial activity is due to the chemical reactivity rather than enzymatic affinity, making it unsuitable for development as an antibacterial drug.
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Alcaloides , Antibacterianos , Alcaloides/química , Antibacterianos/química , Aspergillus , Bacterias Gramnegativas , Bacterias Grampositivas , Pruebas de Sensibilidad Microbiana , PirrolidinonasRESUMEN
Dicer-like proteins (DCLs) play a vital role in RNA interference (RNAi), by cleaving RNA filament into small RNAs. Although DCL-mediated RNAi can regulate interspecific communication between pathogenic/mutualistic organisms and their hosts, its role in mycoparasitic interactions is yet to be investigated. In this study, we deleted dcl genes in the mycoparasitic fungus Clonostachys rosea and characterize the functions of DCL-dependent RNAi in mycoparasitism. Deletion of dcl2 resulted in a mutant with reduced secondary metabolite production, antagonism toward the plant-pathogenic fungus Botrytis cinerea, and reduced ability to control Fusarium foot rot disease on wheat, caused by Fusarium graminearum. Transcriptome sequencing of the in vitro interaction between the C. rosea Δdcl2 strain and B. cinerea or F. graminearum identified the downregulation of genes coding for transcription factors, membrane transporters, hydrolytic enzymes, and secondary metabolites biosynthesis enzymes putatively involved in antagonistic interactions, in comparison with the C. rosea wild-type interaction. A total of 61 putative novel microRNA-like RNAs (milRNAs) were identified in C. rosea, and 11 were downregulated in the Δdcl2 mutant. In addition to putative endogenous gene targets, these milRNAs were predicted to target B. cinerea and F. graminearum virulence factor genes, which showed an increased expression during interaction with the Δdcl2 mutant incapable of producing the targeting milRNAs. In summary, this study constitutes the first step in elucidating the role of RNAi in mycoparasitic interactions, with important implications for biological control of plant diseases, and poses the base for future studies focusing on the role of cross-species RNAi regulating mycoparasitic interactions. IMPORTANCE Small RNAs mediated RNA interference (RNAi) known to regulate several biological processes. Dicer-like endoribonucleases (DCLs) play a vital role in the RNAi pathway by generating sRNAs. In this study, we investigated a role of DCL-mediated RNAi in interference interactions between mycoparasitic fungus Clonostachys rosea and the two fungal pathogens Botrytis cinerea and Fusarium graminearum (here called mycohosts). We found that the dcl mutants were not able to produce 11 sRNAs predicted to finetune the regulatory network of genes known to be involved in production of hydrolytic enzymes, antifungal compounds, and membrane transporters needed for antagonistic action of C. rosea. We also found C. rosea sRNAs putatively targeting known virulence factors in the mycohosts, indicating RNAi-mediated cross-species communication. Our study expanded the understanding of underlying mechanisms of cross-species communication during interference interactions and poses a base for future works studying the role of DCL-based cross-species RNAi in fungal interactions.
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Botrytis/genética , ARN Helicasas DEAD-box/metabolismo , Fusarium/genética , Hypocreales/genética , Interferencia de ARN/fisiología , Ribonucleasa III/metabolismo , Agentes de Control Biológico/metabolismo , Perfilación de la Expresión Génica , Regulación Fúngica de la Expresión Génica/genética , MicroARNs/genética , Enfermedades de las Plantas/microbiología , Transcriptoma/genética , Triticum/microbiologíaRESUMEN
Twenty-eight multidrug-resistant bacterial strains closely related or identical to Pedobacter cryoconitis, Pedobacter lusitanus and Pedobacter steynii were isolated from soil samples by selection for multidrug-resistance. Approximately 3-30% of the selected isolates were identified as Pedobacter, whereas isolation without antibiotics did not yield any isolates of this genus. Next generation sequencing data showed Pedobacter to be on 69th place among the bacterial genera (0.32% of bacterial sequences). The Pedobacter isolates produced a wide array of novel compounds when screened by UHPLC-MS/MSMS, and hierarchical cluster analysis resulted in several distinct clusters of compounds produced by specific isolates of Pedobacter, and most of these compounds were found to be peptides. The Pedobacter strain UP508 produced isopedopeptins, whereas another set of strains produced pedopeptins, which both are known cyclic lipodepsipeptides produced by Pedobacter sp. Other Pedobacter strains produced analogous peptides with a sequence variation. Further strains of Pedobacter produced additional novel antibacterial cyclic lipopeptides (ca 800 or 1400 Da in size) and/or linear lipopeptides (ca 700-960 Da in size). A 16S rRNA phylogenetic tree for the Pedobacter isolates revealed several distinct clades and subclades of isolates. One of the subclades comprised isolates producing isopedopeptin analogs, but the isopedopeptin producing isolate UP508 was clearly placed on a separate branch. We suggest that the non-ribosomal peptide synthases producing pedopeptins, isopedopeptins, and the analogous peptides, may derive from a common ancestral non-ribosomal peptide synthase gene cluster, which may have been subjected to a mutation leading to changed specificity in one of the modules and then to a modular rearrangement leading to the changed sequence found in the isopedopeptins produced by isolate UP508.
RESUMEN
Isopedopeptins are antibiotic cyclic lipodepsipeptides containing the subsequence L-Thr-L-2,3-diaminopropanoic acid-D-Phe-L-Val/L-3-hydroxyvaline. Acidic hydrolysis of isopedopeptins in D2O showed the D-Phe residues to racemize extensively in peptides with L-3-hydroxyvaline but not in peptides with L-Val. Similarly, one Leu residue in pedopeptins, which are related peptides containing the subsequence Leu-2,3-diaminopropanoic acid-Leu-L-Val/L-3-hydroxyvaline, was found to racemize in peptides with L-3-hydroxyvaline. Model tetrapeptides, L-Ala-L-Phe-L-Val/3-hydroxyvaline-L-Ala, gave the corresponding results, i.e. racemization of L-Phe only when linked to a L-3-hydroxyvaline. We propose the racemization to proceed via an oxazoline intermediate involving Phe/Leu and the L-3-hydroxyvaline residues. The 3-hydroxyvaline residue may form a stable tertiary carbocation by loss of the sidechain hydroxyl group as water after protonation. Elimination of the Phe/Leu H-2 and ring-closure from the carbonyl oxygen onto the carbocation results in the suggested oxazoline intermediate. The reversed reaction leads to either retained or inversed configuration of Phe/Leu. Such racemization during acidic hydrolysis may occur whenever a 3-hydroxyvaline residue or any amino acid that can form a stable carbocation on the C-3, is present in a peptide. The proposed mechanism for racemization was supported by incorporation of 18O in the 3-hydroxyvaline sidechain when the acidic hydrolysis was performed in H2O/H218O (1:1). The 2,3-diaminopropanoic residues of isopedopeptins and pedopeptins were also found to racemize during acidic hydrolysis, as previously described. Based on the results, the configuration of the Leu and 2,3-diaminopropanoic acid residues of the pedopeptins were reassigned to be L-Leu and D-Leu, and 2 × L-2,3-diaminopropanoic acid.
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Aminoácidos/química , Oxazoles/química , Péptidos/química , Dipéptidos/química , Hidrólisis , Isomerismo , Péptidos Cíclicos/química , Valina/químicaRESUMEN
Pedobacter cryoconitis strain UP508 was isolated from a soil sample using a mixture of ampicillin, kanamycin, and nalidixic acid for selection. UP508 was found to produce >30 unknown antibacterial peptides, of which eight, isopedopeptins A-H (1-8), were isolated by bioassay-guided fractionation and characterized with respect to structures and biological properties. Compounds 1-8 were all composed of nine amino acid residues and one 3-hydroxy fatty acid residue, and the structures were ring-closed via an ester bond from the C-terminal aspartic acid to the 3-hydroxy fatty acid. The differences between the peptides were the size and branching of the 3-hydroxy fatty acid and the presence of a valine or a 3-hydroxyvaline residue. The isopedopeptins mainly had activity against Gram-negative bacteria, and isopedopeptin B (2), which had the best combination of antibacterial activity, in vitro cytotoxicity, and hemolytic properties, was selected for further studies against a larger panel of Gram-negative bacteria. Isopedopeptin B was found to have good activity against strains of WHO top-priority Gram-negative bacteria, i.e., carbapenem-resistant Acinetobacter baumannii, Escherichia coli, and Pseudomonas aeruginosa, with minimal inhibitory concentrations (MIC) down to 1, 2, and 4 µg/mL, respectively. Furthermore, compound 2 had activity against colistin-resistant strains of A. baumannii, E. coli, and Klebsiella pneumoniae, with a MIC down to 8, 2, and 4 µg/mL, respectively. Compound 6 was tested in an E. coli liposome system where it induced significant leakage, indicating membrane disruption as one mechanism involved in isopedopeptin antibacterial activity. Isopedopeptin B stands out as a promising candidate for further studies with the goal to develop a new antibiotic drug.
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Antibacterianos/farmacología , Carbapenémicos/farmacología , Farmacorresistencia Bacteriana/efectos de los fármacos , Bacterias Gramnegativas/efectos de los fármacos , Pedobacter/química , Péptidos Cíclicos/farmacología , Escherichia coli/efectos de los fármacos , Infecciones por Bacterias Gramnegativas/tratamiento farmacológico , Humanos , Klebsiella pneumoniae/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Péptidos Cíclicos/química , Pseudomonas aeruginosa/efectos de los fármacos , Organización Mundial de la SaludRESUMEN
Biological control is a promising approach to reduce plant diseases caused by nematodes to ensure high productivity in agricultural production. Large-scale analyses of genetic variation in fungal species used for biocontrol can generate knowledge regarding interaction mechanisms that can improve efficacy of biocontrol applications. In this study, we performed a genome-wide association study (GWAS) for in vitro antagonism against the root lesion nematode Pratylenchus penetrans in 53 previously genome re-sequenced strains of the biocontrol fungus Clonostachys rosea. Nematode mortality in C. rosea potato dextrose broth (PDB) culture filtrates was highly variable and showed continuous variation (p < .001) between strains, indicating a polygenic inheritance. Twenty-one strains produced culture filtrates with higher (p ≤ .05) nematode mortality compared with the PDB control treatment, while ten strains lowered (p ≤ .05) the mortality. The difference in in vitro antagonism against P. penetrans correlated with antagonism against the soybean cyst nematode Heterodera glycines, indicating lack of host specificity in C. rosea. An empirical Bayesian multiple hypothesis testing approach identified 279 single nucleotide polymorphism markers significantly (local false sign rate < 10-10) associated with the trait. Genes present in the genomic regions associated with nematicidal activity included several membrane transporters, a chitinase and genes encoding proteins predicted to biosynthesize secondary metabolites. Gene deletion strains of the predicted nonribosomal peptide synthetase genes nps4 and nps5 were generated and showed increased (p ≤ .001) fungal growth and conidiation rates compared to the wild type. Deletion strains also exhibited reduced (p < .001) nematicidal activity and reduced (p ≤ .05) biocontrol efficacy against nematode root disease and against fusarium foot rot on wheat. In summary, we show that the GWAS approach can be used to identify biocontrol factors in C. rosea, specifically the putative nonribosomal peptide synthetases NPS4 and NPS5.
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In the search for new antibiotic compounds, fractionation of Pseudomonas protegens UP46 culture extracts afforded several known Pseudomonas compounds, including 2,4-diacetylphloroglucinol (DAPG), as well as two new antibacterial alkaloids, 6-(pyrrolidin-2-yl)DAPG (1) and 6-(piperidin-2-yl)DAPG (2). The structures of 1 and 2 were determined by nuclear magnetic resonance spectroscopy and mass spectrometry. Compounds 1 and 2 were found to have antibacterial activity against the Gram-positive bacteria Staphylococcus aureus and Bacillus cereus, with minimal inhibitory concentration (MIC) 2 and 4 µg ml-1, respectively, for 1, and 2 µg ml-1 for both pathogens for 2. The MICs for 1 and 2, against all tested Gram-negative bacteria, were >32 µg ml-1. The half maximal inhibitory concentrations against HepG2 cells for compounds 1 and 2 were 11 and 18 µg ml-1, respectively, which suggested 1 and 2 be too toxic for further evaluation as possible new antibacterial drugs. Stable isotope labelling experiments showed the pyrrolidinyl group of 1 to originate from ornithine and the piperidinyl group of 2 to originate from lysine. The P. protegens acetyl transferase (PpATase) is involved in the biosynthesis of monoacetylphloroglucinol and DAPG. No optical rotation was detected for 1 or 2, and a possible reason for this was investigated by studying if the PpATase may catalyse a stereo-non-specific introduction of the pyrrolidinyl/piperidinyl group in 1 and 2, but unless the PpATase can be subjected to major conformational changes, the enzyme cannot be involved in this reaction. The PpATase is, however, likely to catalyse the formation of 2,4,6-triacetylphloroglucinol from DAPG.
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Antibacterianos/aislamiento & purificación , Floroglucinol/análogos & derivados , Pseudomonas/química , Alcaloides/química , Alcaloides/aislamiento & purificación , Alcaloides/farmacología , Antibacterianos/farmacología , Cromatografía Líquida de Alta Presión , Bacterias Gramnegativas/efectos de los fármacos , Células Hep G2/efectos de los fármacos , Humanos , Espectroscopía de Resonancia Magnética , Espectrometría de Masas , Redes y Vías Metabólicas , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Floroglucinol/química , Floroglucinol/aislamiento & purificación , Floroglucinol/farmacologíaRESUMEN
In the search for new microbial antibacterial secondary metabolites, two new compounds (1 and 2) were isolated from culture broths of Penicillium spathulatum Em19. Structure determination by nuclear magnetic resonance and mass spectrometry identified the compounds as 6,7-dihydroxy-5,10-dihydropyrrolo[1,2-b]isoquinoline-3-carboxylic acid (1, spathullin A) and 5,10-dihydropyrrolo[1,2-b]isoquinoline-6,7-diol (2, spathullin B). The two compounds displayed activity against both Gram-negative and -positive bacteria, including Escherichia coli, Acinetobacter baumannii, Enterobacter cloacae, Klebsiella pneumonia, Pseudomonas aeruginosa, and Staphylococcus aureus. Compound 2 was more potent than 1 against all tested pathogens, with minimal inhibitory concentrations down to 1 µg/mL (5 µM) against S. aureus, but 2 was also more cytotoxic than 1 (50% inhibitory concentrations 112 and 11 µM for compounds 1 and 2, respectively, towards Huh7 cells). Based on stable isotope labelling experiments and a literature comparison, the biosynthesis of 1 was suggested to proceed from cysteine, tyrosine and methionine via a non-ribosomal peptides synthase like enzyme complex, whereas compound 2 was formed spontaneously from 1 by decarboxylation. Compound 1 was also easily oxidized to the 1,2-benzoquinone 3. Due to the instability of compound 1 and the toxicity of 2, the compounds are of low interest as possible future antibacterial drugs.
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Alcaloides/química , Alcaloides/farmacología , Antibacterianos/química , Antibacterianos/farmacología , Isoquinolinas/química , Isoquinolinas/farmacología , Penicillium , Alcaloides/aislamiento & purificación , Antibacterianos/aislamiento & purificación , Vías Biosintéticas , Farmacorresistencia Bacteriana , Isoquinolinas/aislamiento & purificación , Espectroscopía de Resonancia Magnética , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Penicillium/química , Penicillium/metabolismoRESUMEN
Heterobasidion annosum s.s. and H. parviporum are severe pathogens of conifers causing butt rot and root rot thus reducing the economic value of timber. Here, the antifungal activity of Bacillus subtilis isolate A18 against these two Heterobasidion species was investigated. Five different culture media with different culture age were investigated to study the effect of substrate composition and culture age for metabolite production. Bacterial cultures and cell-free culture filtrates were tested for antifungal activity. Inhibition of fungal growth was analysed using the agar disc-diffusion method. MALDI-TOF and LC-HRMS analyses were used to identify the antifungal metabolites. Substrate composition and age of culture were found to be active variables with direct effect on the antifungal activity of bacterial culture extracts. High anti-fungal activity was observed when B. subtilis was cultured in PDB, SGB and LB media for four days. Mass-spectrometry analysis showed the presence of lipopeptides in culture filtrates identified as members of the surfactins, polymixins, kurstakins and fengycins. A culture filtrate containing fengycin-type lipopeptides showed the highest bioactivity against Heterobasidion species. Bacterial cultures had higher bioactivity compared to their respective cell free culture filtrates. The results of the present study suggest that B. subtilis A18 is a powerful biocontrol agent against Heterobasidion infections of tree wounds and stumps.
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Antifúngicos/farmacología , Bacillus subtilis/metabolismo , Basidiomycota/efectos de los fármacos , Basidiomycota/crecimiento & desarrollo , Agentes de Control Biológico/metabolismo , Lipopéptidos/antagonistas & inhibidores , Lipopéptidos/metabolismo , Antifúngicos/aislamiento & purificación , Bacillus subtilis/genética , Bacillus subtilis/aislamiento & purificación , Basidiomycota/patogenicidad , Agentes de Control Biológico/aislamiento & purificación , Técnicas de Cocultivo , Pruebas Antimicrobianas de Difusión por Disco , Glucosa , Lipopéptidos/aislamiento & purificación , Enfermedades de las Plantas/microbiología , ARN Ribosómico 16S/genética , Metabolismo Secundario , Espectrometría de Masa por Láser de Matriz Asistida de Ionización DesorciónRESUMEN
Secondary metabolites produced by biological control agents may influence the outcome of their interactions with plant pathogenic microorganisms and plants. In the present study, we investigated the role of the nonribosomal peptide synthetase gene nps1 expressed by the biocontrol fungus Clonostachys rosea. A gene expression analysis showed that nps1 was induced during confrontations with the plant pathogenic fungus Botrytis cinerea. Gene deletion strains of nps1 displayed increased growth rates and conidiation. However, the nematicidal activity of culture filtrates from C. rosea Δnps1 strains was significantly weaker than that from wild-type filtrates (P ≤ 0.001); after 24 h of incubation with culture filtrates from nps1 deletion strains, only 13 to 33% of a mixed community of nematodes were dead compared with 42% of nematodes incubated with wild-type culture filtrates. The Δnps1 strains also showed reduced biocontrol efficacy during pot experiments, thus failing to protect wheat seedlings from foot rot disease caused by the plant pathogenic fungus Fusarium graminearum. Furthermore, C. rosea Δnps1 strains were not able to reduce populations of plant-parasitic nematodes in soil or in roots of wheat as efficiently as the wild-type strain. Both C. rosea wild-type and Δnps1 strains increased the dry shoot weight and shoot length of wheat by 20 and 13%, respectively. We showed that NPS1, a putative nonribosomal peptide synthetase encoded by nps1, is a biocontrol factor, presumably by producing a hitherto unknown nonribosomal peptide compound with antifungal and nematicidal properties that contributes to the biocontrol properties of C. rosea.
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Fusarium , Eliminación de Gen , Genes Fúngicos , Hypocreales , Nematodos , Animales , Fusarium/fisiología , Genes Fúngicos/genética , Hypocreales/enzimología , Hypocreales/genética , Nematodos/microbiología , Péptido Sintasas/genética , Enfermedades de las PlantasRESUMEN
As societies become increasingly diverse, mental health professionals need instruments for assessing emotional, behavioral, and social problems in terms of constructs that are supported within and across societies. Building on decades of research findings, multisample alignment confirmatory factor analyses tested an empirically based 8-syndrome model on parent ratings across 30 societies and youth self-ratings across 19 societies. The Child Behavior Checklist for Ages 6-18 and Youth Self-Report for Ages 11-18 were used to measure syndromes descriptively designated as Anxious/Depressed, Withdrawn/Depressed, Somatic Complaints, Social Problems, Thought Problems, Attention Problems, Rule-Breaking Behavior, and Aggressive Behavior. For both parent ratings (N = 61,703) and self-ratings (N = 29,486), results supported aggregation of problem items into 8 first-order syndromes for all societies (configural invariance), plus the invariance of item loadings (metric invariance) across the majority of societies. Supported across many societies in both parent and self-ratings, the 8 syndromes offer a parsimonious phenotypic taxonomy with clearly operationalized assessment criteria. Mental health professionals in many societies can use the 8 syndromes to assess children and youths for clinical, training, and scientific purposes.
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Padres/psicología , Psicopatología/métodos , Sociedades/normas , Adolescente , Niño , Femenino , Humanos , Masculino , SíndromeRESUMEN
Clonostachys rosea is a mycoparasitic fungus used for biological control of plant diseases. Its genome contains 31 genes putatively encoding for polyketide synthases (PKSs), 75% of which are arranged in biosynthetic gene clusters. Gene expression analysis during C. rosea interactions with the fungal plant pathogens Botrytis cinerea and Fusarium graminearum showed common and species-specific induction of PKS genes. Our data showed a culture media dependent correlation between PKS gene expression and degree of antagonism in C. rosea. The pks22 and pks29 genes were highly induced during fungal-fungal interactions but not during pigmentation, and gene deletion studies revealed that PKS29 was required for full antagonism against B. cinerea, and for biocontrol of fusarium foot rot on barley. Metabolite analysis revealed that Δpks29 strains has a 50% reduced production (P = 0.001) of an unknown polyketide with molecular formula C15H28O3, while Δpks22 strains lost the ability to produce four previously unknown polyketides named Clonorosein A-D. Clonorosein A and B were purified, their structures determined, and showed strong antifungal activity against B. cinerea and F. graminearum. These results show that PKS22 is required for production of antifungal polyketide Clonorosein A-D, and demonstrate the role of PKS29 in antagonism and biocontrol of fungal plant diseases.
Asunto(s)
Genoma Fúngico/genética , Hypocreales/enzimología , Enfermedades de las Plantas/genética , Sintasas Poliquetidas/genética , Agentes de Control Biológico , Botrytis/genética , Botrytis/patogenicidad , Fusarium/genética , Fusarium/patogenicidad , Eliminación de Gen , Regulación Fúngica de la Expresión Génica/genética , Hordeum/genética , Hordeum/microbiología , Filogenia , Enfermedades de las Plantas/microbiología , Especificidad de la EspecieRESUMEN
Our comparative studies reveal that the two lytic polysaccharide monooxygenases HiLPMO9B and HiLPMO9I from the white-rot conifer pathogen Heterobasidion irregulare display clear difference with respect to their activity against crystalline cellulose and glucomannan. HiLPMO9I produced very little soluble sugar on bacterial microcrystalline cellulose (BMCC). In contrast, HiLPMO9B was much more active against BMCC and even released more soluble sugar than the H. irregulare cellobiohydrolase I, HiCel7A. Furthermore, HiLPMO9B was shown to cooperate with and stimulate the activity of HiCel7A, both when the BMCC was first pretreated with HiLPMO9B, as well as when HiLPMO9B and HiCel7A were added together. No such stimulation was shown by HiLPMO9I. On the other hand, HiLPMO9I was shown to degrade glucomannan, using a C4-oxidizing mechanism, whereas no oxidative cleavage activity of glucomannan was detected for HiLPMO9B. Structural modeling and comparison with other glucomannan-active LPMOs suggest that conserved sugar-interacting residues on the L2, L3 and LC loops may be essential for glucomannan binding, where 4 out of 7 residues are shared by HiLPMO9I, but only one is found in HiLPMO9B. The difference shown between these two H. irregulare LPMOs may reflect distinct biological roles of these enzymes within deconstruction of different plant cell wall polysaccharides during fungal colonization of softwood.
Asunto(s)
Basidiomycota/enzimología , Celulosa/química , Proteínas Fúngicas/química , Mananos/química , Oxigenasas de Función Mixta/química , Modelos Moleculares , Celulosa/metabolismo , Proteínas Fúngicas/metabolismo , Mananos/metabolismo , Oxigenasas de Función Mixta/metabolismoRESUMEN
Three cyclopentanoids (phlebiopsin Aâ»C), one glycosylated p-terphenyl (methyl-terfestatin A), and o-orsellinaldehyde were isolated from the biocontrol fungus Phlebiopsis gigantea, and their structures were elucidated by 1D and 2D NMR spectroscopic analysis, as well as by LC-HRMS. The biological activity of the compounds against the root rot fungus Heterobasidion occidentale, as well as against Fusarium oxysporum and Penicillium canescens, was also investigated, but only o-orsellinaldehyde was found to have any antifungal activity in the concentration range tested.
Asunto(s)
Aldehídos/aislamiento & purificación , Antifúngicos/aislamiento & purificación , Catecoles/aislamiento & purificación , Ciclopentanos/aislamiento & purificación , Enfermedades de las Plantas/prevención & control , Polyporales/química , Compuestos de Terfenilo/aislamiento & purificación , Agaricales/efectos de los fármacos , Aldehídos/química , Aldehídos/farmacología , Antifúngicos/química , Antifúngicos/farmacología , Catecoles/química , Catecoles/farmacología , Cromatografía Liquida , Ciclopentanos/química , Ciclopentanos/farmacología , Fusarium/efectos de los fármacos , Espectroscopía de Resonancia Magnética , Estructura Molecular , Penicillium/efectos de los fármacos , Enfermedades de las Plantas/microbiología , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/microbiología , Polyporales/crecimiento & desarrollo , Metabolismo Secundario , Compuestos de Terfenilo/química , Compuestos de Terfenilo/farmacologíaRESUMEN
Plants can detect the presence of their neighbours and modify their growth behaviour accordingly. But the extent to which this neighbour detection is mediated by abiotic stressors is not well known. In this study we tested the acclimation response of Zea mays L. seedlings through belowground interactions to the presence of their siblings exposed to brief mechano stimuli. Maize seedling simultaneously shared the growth solution of touched plants or they were transferred to the growth solution of previously touched plants. We tested the growth preferences of newly germinated seedlings toward the growth solution of touched (T_solution) or untouched plants (C_solution). The primary root of the newly germinated seedlings grew significantly less towards T_solution than to C_solution. Plants transferred to T_solution allocated more biomass to shoots and less to roots. While plants that simultaneously shared their growth solution with the touched plants produced more biomass. Results show that plant responses to neighbours can be modified by aboveground abiotic stress to those neighbours and suggest that these modifications are mediated by belowground interactions.