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1.
Antonie Van Leeuwenhoek ; 114(1): 37-44, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33392934

RESUMEN

A Gram-stain positive, aerobic, motile, rod-shaped bacterium designated as strain CBP-2801T was isolated as a contaminant from a culture containing maize callus in Peoria, Illinois, United States. The strain is unique relative to other Cohnella species due to its slow growth and reduced number of sole carbon sources. Phylogenetic analysis using 16S rRNA indicated that strain CBP-2801T is a Cohnella bacterium and showed the highest similarity to Cohnella xylanilytica (96.8%). Genome-based phylogeny and genomic comparisons based on average nucleotide identity confirmed the strain to be a novel species of Cohnella. Growth occurs at 15-45 °C (optimum 40 °C), pH 5-7 (optimum pH 6) and with 0-1% NaCl. The predominant fatty acids are anteiso-15:0 and 18:1 ω6c. Genome mining for secondary metabolites identified a putative biosynthetic cluster that encodes for a novel lasso peptide. In addition, this study contributes five new genome assemblies of type strains of Cohnella species, a genus with less than 30% of the type strains sequenced. The DNA G + C content is 58.7 mol %. Based on the phenotypic, phylogenetic and biochemical data strain CBP-2801T represents a novel species, for which the name Cohnella zeiphila sp. nov. is proposed. The type strain is CBP-2801T (= DSM 111598 = ATCC TSD-230).


Asunto(s)
Fosfolípidos , Zea mays , Bacillales , Técnicas de Tipificación Bacteriana , Composición de Base , ADN Bacteriano/genética , Ácidos Grasos/análisis , Fosfolípidos/análisis , Filogenia , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN
2.
Antonie Van Leeuwenhoek ; 113(7): 973-987, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32279200

RESUMEN

Onions can be damaged by Fusarium basal rot caused by the soilborne fungus Fusarium oxysporum f. sp. cepae (FOC). Control of this pathogen is challenging since there is limited genetic resistance in onion. The identification of molecules that inhibit this pathogen is needed. Antagonism screening showed Brevibacillus fortis NRS-1210 secreted antifungal compounds into growth medium. The spent growth medium, diluted 1:1, inhibited growth of FOC conidia after seven hours and killed 67-91% of conidia after 11 h. The spent medium also inhibited growth of propagules from F. graminearum, F. proliferatum, F. verticillioides and Galactomyces citri-aurantii. Full strength spent growth medium did not effectively kill FOC conidia and chlamydospores inoculated into a sand cornmeal mixture. In silico analysis of the B. fortis NRS-1210 genome indicated the biosynthetic clusters of several antibiotics. Fractionation of spent medium followed by reverse-phase liquid chromatography with tandem mass spectrometry analysis found that fractions with the most antifungal activity contained a combination of edeines A, B and F and no other recognized antibiotics. 1H NMR signals of the active fraction corresponded to edeine, a pentapeptide with broad spectrum antimicrobial activity which blocks translation in both prokaryotes and eukaryotes. Comparative genomics of Brevibacillus genomes shows edeine producers form a clade which consists of: Brevibacillus brevis, Brevibacillus formosus, 'Brevibacillus antibioticus', Brevibacillus schisleri, Brevibacillus fortis, and Brevibacillus porteri. This observation suggests edeine played an important role in the evolution and speciation of the Brevibacillus genus.


Asunto(s)
Brevibacillus/metabolismo , Edeína/biosíntesis , Edeína/farmacología , Fusarium/efectos de los fármacos , Cebollas/microbiología , Enfermedades de las Plantas/prevención & control , Esporas Fúngicas/efectos de los fármacos , Antifúngicos/farmacología , Brevibacillus/clasificación , Brevibacillus/genética , Edeína/química , Genoma Bacteriano/genética , Filogenia , Enfermedades de las Plantas/microbiología , Saccharomycetales/efectos de los fármacos , Metabolismo Secundario/genética
3.
Antonie Van Leeuwenhoek ; 112(7): 991-999, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-30693434

RESUMEN

During a screen for antifungal activity of Brevibacillus strains in the Northern Regional Research Laboratory collection we identified two strains with strong activity. Subsequent genomic sequencing and phylogenomic analysis revealed that these strains (NRRL NRS-1210T and NRRL B-41110T) are likely novel species. To confirm their taxonomic placement, we conducted a 16S rRNA phylogenetic analysis and subsequently sequenced the genomes of 10 Brevibacillus type strains with a 16S homology > 97%. Phylogenomic analysis of these type strains and of representative Brevibacillus strains deposited in GenBank also identified several novel clades that should be recognised as novel species. For one of these novel clades, we were able to obtain a publicly available isolate (ATCC 35690T) that could serve as a type strain. The three new species were subjected to a polyphasic characterisation to confirm their taxonomic status. Cells of strains NRRL NRS-1210T, NRRL B-41110T and ATCC 35690T are Gram-staining positive, motile and form tan colonies. All three strains are obligate aerobic mesophiles with a broad pH range for growth. The two most prominent fatty acids of the three strains were identified as iso-C15:0 and anteiso-C15:0. The DNA G+C contents of strains NRRL NRS-1210T, NRRL B-41110T and ATCC 35690T are 47.2 mol%, 47.1 mol% and 47.3 mol%, respectively. Based on these characteristics, three novel species are proposed: Brevibacillus fortis sp. nov. (NRRL NRS-1210T = DSM 9886T = ATCC 51666T), Brevibacillus porteri sp. nov. (NRRL B-41110T = KACC 19693T) and Brevibacillus schisleri sp. nov. (ATCC 35690T = LMG 17055T).


Asunto(s)
Brevibacillus/clasificación , Filogenia , Composición de Base , Brevibacillus/genética , Brevibacillus/aislamiento & purificación , Brevibacillus/metabolismo , ADN Bacteriano/genética , ADN Ribosómico/genética , Ácidos Grasos/química , Ácidos Grasos/metabolismo , Genoma Bacteriano , ARN Ribosómico 16S/genética
4.
J Plant Res ; 129(1): 13-20, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26659597

RESUMEN

Mycotoxin presence in maize causes health and economic issues for humans and animals. Although many studies have investigated expression differences of genes putatively governing resistance to producing fungi, few have confirmed a resistance role, or examined putative resistance gene structure in more than a couple of inbreds. The pericarp expression of maize Px5 has previously been associated with resistance to Aspergillus flavus growth and insects in a set of inbreds. Genes from 14 different inbreds that included ones with resistance and susceptibility to A. flavus, Fusarium proliferatum, F. verticillioides and F. graminearum and/or mycotoxin production were cloned using high fidelity enzymes, and sequenced. The sequence of Px5 from all resistant inbreds was identical, except for a single base change in two inbreds, only one of which affected the amino acid sequence. Conversely, the Px5 sequence from several susceptible inbreds had several base variations, some of which affected amino acid sequence that would potentially alter secondary structure, and thus enzyme function. The sequence of the maize peroxidase Px5 common to inbreds resistant to mycotoxigenic fungi was overexpressed in maize callus. Callus transformants overexpressing the gene caused significant reductions in growth for fall armyworms, corn earworms, and F. graminearum compared to transformant callus with a ß-glucuronidase gene. This study demonstrates rarer transcripts of potential resistance genes overlooked by expression screens can be identified by sequence comparisons. A role in pest resistance can be verified by callus expression of the candidate genes, which can thereby justify larger scale transformation and regeneration of transgenic plants expressing the resistance gene for further evaluation.


Asunto(s)
Peroxidasas/genética , Peroxidasas/metabolismo , Enfermedades de las Plantas/genética , Proteínas de Plantas/genética , Zea mays/genética , Zea mays/microbiología , Aspergillus/fisiología , Secuencia de Bases , Secuencia Conservada , Fusarium/fisiología , Micotoxinas/farmacología , Fitomejoramiento , Enfermedades de las Plantas/microbiología , Proteínas de Plantas/metabolismo , Análisis de Secuencia de ADN , Zea mays/efectos de los fármacos , Zea mays/enzimología
5.
J Exp Bot ; 66(14): 4317-35, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-26093023

RESUMEN

The phenylpropanoid pathway in plants synthesizes a variety of structural and defence compounds, and is an important target in efforts to reduce cell wall lignin for improved biomass conversion to biofuels. Little is known concerning the trade-offs in grasses when perturbing the function of the first gene family in the pathway, PHENYLALANINE AMMONIA LYASE (PAL). Therefore, PAL isoforms in the model grass Brachypodium distachyon were targeted, by RNA interference (RNAi), and large reductions (up to 85%) in stem tissue transcript abundance for two of the eight putative BdPAL genes were identified. The cell walls of stems of BdPAL-knockdown plants had reductions of 43% in lignin and 57% in cell wall-bound ferulate, and a nearly 2-fold increase in the amounts of polysaccharide-derived carbohydrates released by thermochemical and hydrolytic enzymic partial digestion. PAL-knockdown plants exhibited delayed development and reduced root growth, along with increased susceptibilities to the fungal pathogens Fusarium culmorum and Magnaporthe oryzae. Surprisingly, these plants generally had wild-type (WT) resistances to caterpillar herbivory, drought, and ultraviolet light. RNA sequencing analyses revealed that the expression of genes associated with stress responses including ethylene biosynthesis and signalling were significantly altered in PAL knocked-down plants under non-challenging conditions. These data reveal that, although an attenuation of the phenylpropanoid pathway increases carbohydrate availability for biofuel, it can adversely affect plant growth and disease resistance to fungal pathogens. The data identify notable differences between the stress responses of these monocot pal mutants versus Arabidopsis (a dicot) pal mutants and provide insights into the challenges that may arise when deploying phenylpropanoid pathway-altered bioenergy crops.


Asunto(s)
Biomasa , Brachypodium/genética , Fenilanina Amoníaco-Liasa/genética , Estrés Fisiológico
6.
Mol Genet Genomics ; 289(5): 895-902, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24858840

RESUMEN

The piggyBac transposable element, originally isolated from a virus in an insect cell line, is a valuable molecular tool for transgenesis and mutagenesis of invertebrates. For heterologous transgenesis in a variety of mammals, transfer of the piggyBac transposable element from an ectopic plasmid only requires expression of piggyBac transposase. To determine if piggyBac could function in dicotyledonous plants, a two-element system was developed in tobacco (Nicotiana tabacum) to test for transposable element excision and insertion. The first transgenic line constitutively expressed piggyBac transposase, while the second transgenic line contained at least two non-autonomous piggyBac transposable elements. Progeny from crosses of the two transgenic lines was analyzed for piggyBac excision and transposition. Several progeny displayed excision events, and all the sequenced excision sites exhibited evidence of the precise excision mechanism characteristic of piggyBac transposase. Two unique transposition insertion events were identified that each included diagnostic duplication of the target site. These data indicate that piggyBac transposase is active in a dicotyledonous plant, although at a low frequency.


Asunto(s)
Elementos Transponibles de ADN/genética , Genes de Insecto , Nicotiana/genética , Plantas Modificadas Genéticamente/genética , Ingeniería Genética , Mutagénesis Insercional
7.
Biotechnol Lett ; 36(8): 1735-42, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-24770871

RESUMEN

Lycotoxin I, from the wolf spider (Lycosa carolinensis), is an amphipathic pore-forming peptide that has antimicrobial and anti-insect activity. Constitutive expression of a lycotoxin I modified for oral toxicity to insects in tobacco (Nicotiana tabacum) conferred significantly enhanced resistance to larvae of the corn earworm (Helicoverpa zea) and cigarette beetle (Lasioderma serricorne). Gene expression levels of modified lycotoxin I were negatively correlated to the survival of corn earworm larvae. In addition, pathogenic symptoms caused by Pseudomonas syringae pathovar tabaci and Alternaria alternata on the modified lycotoxin I-expressing leaves were significantly less severe than on wild type leaves. These results indicate that modified lycotoxin I expression in tobacco can potentially protect leaf tissue from a broad spectrum of pests and pathogens.


Asunto(s)
Bacterias/crecimiento & desarrollo , Insectos/crecimiento & desarrollo , Nicotiana/metabolismo , Venenos de Araña/metabolismo , Arañas/química , Animales , Bacterias/efectos de los fármacos , Bioensayo , Cruzamientos Genéticos , Resistencia a la Enfermedad , Insectos/efectos de los fármacos , Larva/fisiología , Enfermedades de las Plantas/inmunología , Hojas de la Planta/anatomía & histología , Hojas de la Planta/metabolismo , Plantas Modificadas Genéticamente , Reacción en Cadena de la Polimerasa , Nicotiana/genética , Nicotiana/inmunología
8.
Microorganisms ; 11(6)2023 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-37375052

RESUMEN

Tar spot disease in corn, caused by Phyllachora maydis, can reduce grain yield by limiting the total photosynthetic area in leaves. Stromata of P. maydis are long-term survival structures that can germinate and release spores in a gelatinous matrix in the spring, which are thought to serve as inoculum in newly planted fields. In this study, overwintered stromata in corn leaves were collected in Central Illinois, surface sterilized, and caged on water agar medium. Fungi and bacteria were collected from the surface of stromata that did not germinate and showed microbial growth. Twenty-two Alternaria isolates and three Cladosporium isolates were collected. Eighteen bacteria, most frequently Pseudomonas and Pantoea species, were also isolated. Spores of Alternaria, Cladosporium, and Gliocladium catenulatum (formulated as a commercial biofungicide) reduced the number of stromata that germinated compared to control untreated stromata. These data suggest that fungi collected from overwintered tar spot stromata can serve as biological control organisms against tar spot disease.

9.
Sci Rep ; 13(1): 14292, 2023 08 31.
Artículo en Inglés | MEDLINE | ID: mdl-37653049

RESUMEN

The compound 2,4-diacetylphloroglucinol (DAPG) is a broad-spectrum antibiotic that is primarily produced by Pseudomonas spp. DAPG plays an important role in the biocontrol disease suppressing activity of Pseudomonas spp. In the current study, we report the discovery of the DAPG biosynthetic cluster in strains of Chromobacterium vaccinii isolated from Brazilian aquatic environments and the distribution of the biosynthetic cluster in the Chromobacterium genus. Phylogenetic analysis of the phlD protein suggests the biosynthetic cluster probably entered the genus of Chromobacterium after a horizontal gene transfer event with a member of the Pseudomonas fluorescens group. We were able to detect trace amounts of DAPG in wild type cultures and confirm the function of the cluster with heterologous expression in Escherichia coli. In addition, we identified and verified the presence of other secondary metabolites in these strains. We also confirmed the ability of C. vaccinii strains to produce bioactive pigment violacein and bioactive cyclic depsipeptide FR900359. Both compounds have been reported to have antimicrobial and insecticidal activities. These compounds suggest strains of C. vaccinii should be further explored for their potential as biocontrol agents.


Asunto(s)
Antibacterianos , Chromobacterium , Chromobacterium/genética , Filogenia , Antibacterianos/farmacología , Brasil , Escherichia coli , Pseudomonas
10.
PLoS One ; 18(6): e0285685, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37262030

RESUMEN

Protein transporters move essential metabolites across membranes in all living organisms. Downy mildew causing plant pathogens are biotrophic oomycetes that transport essential nutrients from their hosts to grow. Little is known about the functions and gene expression levels of membrane transporters produced by downy mildew causing pathogens during infection of their hosts. Approximately 170-190 nonredundant transporter genes were identified in the genomes of Peronospora belbahrii, Peronospora effusa, and Peronospora tabacina, which are specialized pathogens of basil, spinach, and tobacco, respectively. The largest groups of transporter genes in each species belonged to the major facilitator superfamily, mitochondrial carriers (MC), and the drug/metabolite transporter group. Gene expression of putative Peronospora transporters was measured using RNA sequencing data at two time points following inoculation onto leaves of their hosts. There were 16 transporter genes, seven of which were MCs, expressed in each Peronospora species that were among the top 45 most highly expressed transporter genes 5-7 days after inoculation. Gene transcripts encoding the ADP/ATP translocase and the mitochondrial phosphate carrier protein were the most abundant mRNAs detected in each Peronospora species. This study found a number of Peronospora genes that are likely critical for pathogenesis and which might serve as future targets for control of these devastating plant pathogens.


Asunto(s)
Oomicetos , Peronospora , Peronospora/genética , Enfermedades de las Plantas/genética , Oomicetos/genética , Análisis de Secuencia de ARN , Expresión Génica
11.
J Chem Ecol ; 38(10): 1247-63, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23135603

RESUMEN

Microarray analysis was used to measure the impact of herbivory by Helicoverpa zea, (corn earworm caterpillar) on wild-type and transgenic tomato, Solanum lycopersicum, plants that over-express peroxidase. Caterpillar herbivory had by far the greatest affect on gene expression, but the peroxidase transgene also altered the expression of a substantial number of tomato genes. Particularly high peroxidase activity resulted in the up-regulation of genes encoding proteinase inhibitors, pathogenesis-related (PR) proteins, as well as proteins associated with iron and calcium transport, and flowering. In a separate experiment conducted under similar conditions, real-time quantitative polymerase chain reaction (qPCR) analysis confirmed our microarray results for many genes. There was some indication that multiple regulatory interactions occurred due to the interaction of the different treatments. While herbivory had the greatest impact on tomato gene expression, our results suggest that levels of expression of a multifunctional gene, such as peroxidase and its products, can influence other gene expression systems distinct from conventional signaling pathways, further indicating the complexity of plant defensive responses to insects.


Asunto(s)
Regulación de la Expresión Génica de las Plantas , Herbivoria , Mariposas Nocturnas/fisiología , Peroxidasa/metabolismo , Proteínas de Plantas/metabolismo , Solanum lycopersicum/genética , Animales , Solanum lycopersicum/metabolismo , Análisis de Secuencia por Matrices de Oligonucleótidos , Peroxidasa/genética , Proteínas de Plantas/genética , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa
12.
Int J Food Microbiol ; 370: 109633, 2022 Jun 02.
Artículo en Inglés | MEDLINE | ID: mdl-35313251

RESUMEN

Natural food flavour (E)-2-hexenal, a green leaf volatile, exhibits potent antifungal activity on Aspergillus flavus, but its antifungal mechanism has not been fully elucidated. In this study, we evaluated (E)-2-hexenal-induced apoptosis in A. flavus conidia and explored the underlying mechanisms of action. Evidence of apoptosis in A. flavus conidia were investigated by methods including fluorescent staining, flow cytometry, confocal laser scanning microscope, and spectral analysis. Results indicated that 4.0 µL/mL (minimum fungicidal concentration, MFC) of (E)-2-hexenal application induced early markers of apoptotic cell death in A. flavus conidia with a rate of 38.4% after 6 h exposure. Meanwhile, typical hallmarks of apoptosis, such as decreased mitochondrial membrane potential (MMP), activated metacaspase activity, fragmented DNA, mitochondrial permeability transition pore (MPTP) opening and cytochrome c (Cyt C) release from mitochondria to the cytosol were also confirmed. Furthermore, intracellular ATP levels were reduced by 63.3 ± 3.6% and reactive oxygen species (ROS) positive cells increased by 31.1 ± 3.1% during A. flavus apoptosis induced by (E)-2-hexenal. l-Cysteine (Cys), an antioxidant, could strongly block the excess ROS generation caused by (E)-2-hexenal, which correspondingly resulted in a significant inhibition of MPTP opening and decrease of apoptosis in A. flavus, indicating that ROS palys a pivotal role in (E)-2-hexenal-induced apoptosis. These results suggest that (E)-2-hexenal exerts its antifungal effect on A. flavus conidia via a ROS-dependent mitochondrial apoptotic pathway.


Asunto(s)
Antifúngicos , Aspergillus flavus , Aldehídos , Antifúngicos/metabolismo , Antifúngicos/farmacología , Apoptosis , Aspergillus flavus/metabolismo , Aditivos Alimentarios/farmacología , Mitocondrias , Especies Reactivas de Oxígeno/metabolismo , Esporas Fúngicas
13.
Mol Genet Genomics ; 285(6): 517-25, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21556895

RESUMEN

As maize seedlings germinate into the soil, they encounter an environment teeming with insects seeking rich sources of nutrition. Maize presumably has developed a number of molecular mechanisms to ensure survival at the beginning of its life cycle. Comparative transcription analysis using microarrays was utilized to document the expression of a number of genes with potential defensive functions in seedling tissue. In addition to elevated levels of the genes involved in the biosynthesis of DIMBOA (2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one), an anti-insect resistance molecule, other highly expressed genes in the seedling encode the following putative defensive proteins: defensin, hydroxyproline and proline-rich protein, thaumatin-like protein, lipase, cystatin, protease inhibitor, and a variety of proteases. The potential resistance genes identified occurred mainly on chromosomes 1 and 5 in the B73 genome. Analysis of promoters of seven DIMBOA biosynthetic genes identified three transcription factor binding sites that are possibly involved in regulation of the DIMBOA biosynthetic pathway. The results indicate that maize employs a wide variety of potential resistance mechanisms in seedling tissue to resist a possible insect attack.


Asunto(s)
Perfilación de la Expresión Génica/métodos , Genes de Plantas/inmunología , Lepidópteros/fisiología , Plantones/inmunología , Zea mays/genética , Animales , Benzoxazinas , Redes y Vías Metabólicas/genética , Regiones Promotoras Genéticas , Plantones/genética , Zea mays/inmunología
14.
J Chem Ecol ; 37(5): 443-9, 2011 May.
Artículo en Inglés | MEDLINE | ID: mdl-21503618

RESUMEN

A variety of glycosylated and unglycosylated saponins from seven different plant families (Aquifoliaceae, Asparagaceae, Caryophyllaceae, Dioscoreaceae, Leguminosae, Rosaceae, Sapindaceae) were tested against the corn earworm, Helicoverpa zea, and the fall armyworm, Spodoptera frugiperda. The corn earworm feeds readily on both monocots and dicots, while the fall armyworm is primarily a grass feeder. Most of the saponins were similarly effective or ineffective against both insect species, with the glycosides being the primary active form (compared to aglycones). However, one aglycone possessed antifeedant properties toward the fall armyworm. Thus, in contrast to many plant secondary metabolites effective against either of these two species where the aglycone is more effective, in the case of the saponins the opposite is generally true. This appears to be a contradictory strategy of plant defenses that requires further consideration. The activity of protodioscin against insects is reported for the first time and may be important in insect defense by the bioenergy crop switchgrass.


Asunto(s)
Interacciones Huésped-Parásitos , Lepidópteros/fisiología , Plantas/metabolismo , Plantas/parasitología , Saponinas/metabolismo , Spodoptera/fisiología , Animales , Plantas/química , Saponinas/química , Saponinas/aislamiento & purificación
15.
Plasmid ; 61(1): 22-38, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-18831987

RESUMEN

A three-plasmid yeast expression system utilizing the portable small ubiquitin-like modifier (SUMO) vector set combined with the efficient endogenous yeast protease Ulp1 was developed for production of large amounts of soluble functional protein in Saccharomyces cerevisiae. Each vector has a different selectable marker (URA, TRP, or LEU), and the system provides high expression levels of three different proteins simultaneously. This system was integrated into the protocols on a fully automated plasmid-based robotic platform to screen engineered strains of S. cerevisiae for improved growth on xylose. First, a novel PCR assembly strategy was used to clone a xylose isomerase (XI) gene into the URA-selectable SUMO vector and the plasmid was placed into the S. cerevisiae INVSc1 strain to give the strain designated INVSc1-XI. Second, amino acid scanning mutagenesis was used to generate a library of mutagenized genes encoding the bioinsecticidal peptide lycotoxin-1 (Lyt-1) and the library was cloned into the TRP-selectable SUMO vector and placed into INVSc1-XI to give the strain designated INVSc1-XI-Lyt-1. Third, the Yersinia pestis xylulokinase gene was cloned into the LEU-selectable SUMO vector and placed into the INVSc1-XI-Lyt-1 yeast. Yeast strains expressing XI and xylulokinase with or without Lyt-1 showed improved growth on xylose compared to INVSc1-XI yeast.


Asunto(s)
Isomerasas Aldosa-Cetosa/metabolismo , Fosfotransferasas (Aceptor de Grupo Alcohol)/metabolismo , Plásmidos/genética , Saccharomyces cerevisiae/metabolismo , Proteínas Modificadoras Pequeñas Relacionadas con Ubiquitina/genética , Venenos de Araña/metabolismo , Xilosa/metabolismo , Isomerasas Aldosa-Cetosa/genética , Clonación Molecular , Vectores Genéticos , Microscopía Electrónica de Rastreo , Microscopía Electrónica de Transmisión , Mutación , Fosfotransferasas (Aceptor de Grupo Alcohol)/genética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crecimiento & desarrollo , Saccharomyces cerevisiae/ultraestructura , Proteínas Modificadoras Pequeñas Relacionadas con Ubiquitina/metabolismo , Venenos de Araña/genética , Transformación Genética
16.
Heliyon ; 5(1): e01117, 2019 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-30766928

RESUMEN

Basil downy mildew caused by Peronospora belbahrii is a disease of sweet basil (Ocimum basilicum) production worldwide. In this study, sweet basil was grown in plant growth chambers and inoculated with sporangia of P. belbahrii harvested from previously infected plants. Plants were placed in closed, clear plastic bags and leaves harvested over time and observed using scanning electron microscopy. In most cases, sporangia germinated myceliogenically on abaxial and adaxial leaf surfaces as early as three days after inoculation. Germ tubes and the tips of hyphae ramifying on leaf surfaces directly penetrated basil leaves to initiate the infection process. Hyphal growth was not observed to gain entrance to the interior of leaves through stomata, though growth over these openings was observed. Most frequently, seven days after inoculation, one or more sporangiophores grew through stomata to produce new sporangia on both the abaxial and adaxial surfaces of leaves. Macroscopic signs of infection were visible on both sides of leaves approximately ten days after inoculation under the conditions of this study. These results contribute to a better understanding of the infection process and disease onset of P. belbahrii and should help in the development of more effective measures for reducing basil downy mildew.

18.
Mycotoxin Res ; 34(1): 29-37, 2018 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29164518

RESUMEN

The fungus Fusarium verticillioides is a maize pathogen that can produce fumonisin mycotoxins in ears under certain environmental conditions. Because fumonisins pose health risks to humans and livestock, control strategies with minimal risk to the environment are needed to reduce fumonisin contamination. Host-induced gene silencing is a promising technique in which double-stranded RNA expressed in the plant host is absorbed by an invading fungus and down-regulates genes critical for pathogenicity or mycotoxin production in the fungus. A key preliminary step of this technique is identification of DNA segments within the targeted fungal gene that can effectively silence the gene. Here, we used segments of the fumonisin biosynthetic gene FUM1 to generate double-stranded RNA in F. verticillioides. Several of the resulting transformants exhibited reduced FUM1 gene expression and fumonisin production (24- to 3675-fold reduction in fumonisin FB1). Similar reductions in fumonisin production resulted from double-stranded RNA constructs with segments of FUM8, another fumonisin biosynthetic gene (3.5- to 2240-fold reduction in fumonisin FB1). FUM1 or FUM8 silencing constructs were transformed into three isolates of F. verticillioides. Whole genome sequence analysis of seven transformants revealed that reductions in fumonisin production were not due to mutation of the fumonisin biosynthetic gene cluster and revealed a complex pattern of plasmid integration. These results suggest the cloned FUM1 or FUM8 gene segments could be expressed in maize for host-induced gene silencing of fumonisin production.


Asunto(s)
Fumonisinas/metabolismo , Fusarium/genética , Fusarium/metabolismo , Venenos/metabolismo , Interferencia de ARN , Vías Biosintéticas/genética , Regulación Fúngica de la Expresión Génica , Genes Fúngicos , Transformación Genética , Zea mays/microbiología
19.
Artículo en Inglés | MEDLINE | ID: mdl-30110896

RESUMEN

The purpose of this study is to understand among a convenience sample of 400 adults aged 60 years of age or older (1) reasons for being willing or unwilling to participate in a vaccine clinical research study and (2) overall perceptions about vaccine clinical research. A cross-sectional study using a sample of older adults residing in the metro-Atlanta area and surrounding neighborhoods was conducted. The study questionnaire contained 37 questions, including questions about socio-demographics and perceptions about clinical trial processes. Statistical analysis was conducted using logistic regression. The adjusted modeling results indicated that sex, distance to research clinic, and being informed about the research findings played a role in the likelihood of an elderly person participating in a vaccine study. Males were more likely to participate in clinical trials as compared to females (OR: 2.486; CI: 1.042⁻5.934). Most participants were willing to travel up to 25 miles from the research clinic. Of the respondents, 45% were unlikely to participate if the results of the current trial are not shared. Improving access to clinical trials in terms of distance traveled and ensuring streamlined processes to inform participants about the results of the trial in the future would increase willingness to participate in vaccine clinical trials. The survey could serve as a useful tool for conducting vaccine studies and other clinical trials by understanding the barriers specific to the elderly.


Asunto(s)
Ensayos Clínicos como Asunto/psicología , Voluntarios Sanos/psicología , Vacunas/administración & dosificación , Factores de Edad , Anciano , Anciano de 80 o más Años , Estudios Transversales , Femenino , Estado de Salud , Humanos , Modelos Logísticos , Masculino , Persona de Mediana Edad , Factores Sexuales , Factores Socioeconómicos , Encuestas y Cuestionarios , Transportes
20.
J Agric Food Chem ; 55(9): 3421-8, 2007 May 02.
Artículo en Inglés | MEDLINE | ID: mdl-17417870

RESUMEN

Insect chitin is a potential target for resistance plant proteins, but plant-derived chitin-degrading enzymes active against insects are virtually unknown. Commercial beta-N-acetylhexosaminidase (NAHA), a chitin-degrading enzyme from jack bean Canavalia ensiformis, caused significant mortality of fall armyworm Spodoptera frugiperda larvae at 75 microg/gm, but no significant mortality was noted with Aspergillus niger NAHA. Maize Zea mays callus transformed to express an Arabidopsis thaliana clone that putatively codes for NAHA caused significantly higher mortality of cigarette beetle Lasioderma serricorne larvae and significantly reduced growth rates (as reflected by survivor weights) of S. frugiperda as compared to callus that expressed control cDNAs. Tassels from model line Hi-II maize (Z. mays) plants transformed with the NAHA gene fed to S. frugiperda caused significantly higher mortality than tassels transformed to express glucuronidase; mortality was significantly correlated with NAHA expression levels detected histochemically. Leaf disks from inbred Oh43 maize plants transformed with the NAHA gene on average had significantly less feeding by caterpillars than null transformants. Leaf disks of Oh43 transformants caused significant mortality of both S. frugiperda and corn earworm Helicoverpa zea larvae, which was associated with higher expression levels of NAHA detected by isoelectric focusing, histochemically, or with antibody. Overall, these results suggest that plant NAHA has a role in insect resistance. Introduction of NAHA genes or enhancement of activity through breeding or genetic engineering has the potential to significantly reduce insect damage and thereby indirectly reduce mycotoxins that are harmful to animals and people.


Asunto(s)
Insecticidas/administración & dosificación , Spodoptera , beta-N-Acetilhexosaminidasas/administración & dosificación , Animales , Canavalia/enzimología , Expresión Génica , Larva , Plantas Modificadas Genéticamente/enzimología , Semillas/enzimología , Zea mays/enzimología , Zea mays/genética , beta-N-Acetilhexosaminidasas/genética
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