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1.
Ann Rheum Dis ; 81(5): 644-652, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35144926

RESUMEN

OBJECTIVE: To comparatively analyse the aberrant affinity maturation of the antinuclear and rheumatoid factor (RF) B cell repertoires in blood and tissues of patients with Sjögren's syndrome (SjS) using an integrated omics workflow. METHODS: Peptide sequencing of anti-Ro60, anti-Ro52, anti-La and RF was combined with B cell repertoire analysis at the DNA, RNA and single cell level in blood B cell subsets, affected salivary gland and extranodal marginal zone lymphomas of mucosa-associated lymphoid tissue (MALT) of patients with SjS. RESULTS: Affected tissues contained anti-Ro60, anti-Ro52, anti-La and RF clones as a small part of a polyclonal infiltrate. Anti-Ro60, anti-La and anti-Ro52 clones outnumbered RF clones. MALT lymphoma tissues contained monoclonal RF expansions. Autoreactive clones were not selected from a restricted repertoire in a circulating B cell subset. The antinuclear antibody (ANA) repertoires displayed similar antigen-dependent and immunoglobulin (Ig) G1-directed affinity maturation. RF clones displayed antigen-dependent, IgM-directed and more B cell receptor integrity-dependent affinity maturation. This coincided with extensive intra-clonal diversification in RF-derived lymphomas. Regeneration of clinical disease manifestations after rituximab coincided with large RF clones, which not necessarily belonged to the lymphoma clone, that displayed continuous affinity maturation and intra-clonal diversification. CONCLUSION: The ANA and RF repertoires in patients with SjS display tissue-restricted, antigen-dependent and divergent affinity maturation. Affinity maturation of RF clones deviates further during RF clone derived lymphomagenesis and during regeneration of the autoreactive repertoire after temporary disruption by rituximab. These data give insight into the molecular mechanisms of autoreactive inflammation in SjS, assist MALT lymphoma diagnosis and allow tracking its response to rituximab.


Asunto(s)
Linfoma de Células B de la Zona Marginal , Proteogenómica , Síndrome de Sjögren , Linfocitos B/inmunología , Linfocitos B/metabolismo , Humanos , Inmunoglobulina G/inmunología , Factor Reumatoide/metabolismo , Rituximab/uso terapéutico , Síndrome de Sjögren/inmunología
2.
Theor Appl Genet ; 135(6): 2121-2145, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35583656

RESUMEN

KEY MESSAGE: Several Fusarium wilt resistance genes were discovered, genetically and physically mapped, and rapidly deployed via marker-assisted selection to develop cultivars resistant to Fusarium oxysporum f. sp. fragariae, a devastating soil-borne pathogen of strawberry. Fusarium wilt, a soilborne disease caused by Fusarium oxysporum f. sp. fragariae, poses a significant threat to strawberry (Fragaria [Formula: see text] ananassa) production in many parts of the world. This pathogen causes wilting, collapse, and death in susceptible genotypes. We previously identified a dominant gene (FW1) on chromosome 2B that confers resistance to race 1 of the pathogen, and hypothesized that gene-for-gene resistance to Fusarium wilt was widespread in strawberry. To explore this, a genetically diverse collection of heirloom and modern cultivars and octoploid ecotypes were screened for resistance to Fusarium wilt races 1 and 2. Here, we show that resistance to both races is widespread in natural and domesticated populations and that resistance to race 1 is conferred by partially to completely dominant alleles among loci (FW1, FW2, FW3, FW4, and FW5) found on three non-homoeologous chromosomes (1A, 2B, and 6B). The underlying genes have not yet been cloned and functionally characterized; however, plausible candidates were identified that encode pattern recognition receptors or other proteins known to confer gene-for-gene resistance in plants. High-throughput genotyping assays for SNPs in linkage disequilibrium with FW1-FW5 were developed to facilitate marker-assisted selection and accelerate the development of race 1 resistant cultivars. This study laid the foundation for identifying the genes encoded by FW1-FW5, in addition to exploring the genetics of resistance to race 2 and other races of the pathogen, as a precaution to averting a Fusarium wilt pandemic.


Asunto(s)
Fragaria , Fusarium , Cromosomas , Fragaria/genética , Enfermedades de las Plantas/genética
3.
Plant Dis ; 106(5): 1401-1407, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-34879728

RESUMEN

Previous research determined that Fusarium acuminatum and F. avenaceum are important causal agents of a canker disease in bareroot-propagated fruit and nut trees in California that emerges during cold storage or after transplanting. The disease largely disappeared after 2001, but it reemerged in 2011 in almond trees in at least one nursery. This motivated further study of the etiology and epidemiology of the disease by undertaking studies to determine distribution of the pathogens throughout almond nursery propagation systems and trace possible sources of inoculum. Research initiated in 2013 detected pathogenic Fusarium spp. throughout the almond propagation system, including in healthy trees, in soils, on wheat rotation crops, on equipment, and in the cold-storage facility air. In addition to the two Fusarium spp. implicated previously, F. brachygibbosum and a new Fusarium species, F. californicum, were found to be pathogenic on almond trees. Multilocus sequence typing and somatic compatibility testing confirmed that isolates within a species collected from different materials in the nursery were all highly genetically similar and likely of one clonal lineage. These findings affirm that equipment surfaces, wheat rotation crops, soil, cold-storage facility air, and asymptomatic almond tree materials (i.e., rootstock cuttings, budwood, and scions) can potentially contribute inoculum to increase disease prevalence and severity.


Asunto(s)
Fusarium , Casas Cuna , Prunus dulcis , Fusarium/genética , Variación Genética , Humanos , Lactante , Árboles , Triticum
4.
New Phytol ; 230(1): 327-340, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33616938

RESUMEN

The genes required for host-specific pathogenicity in Fusarium oxysporum can be acquired through horizontal chromosome transfer (HCT). However, it is unknown if HCT commonly contributes to the diversification of pathotypes. Using comparative genomics and pathogenicity phenotyping, we explored the role of HCT in the evolution of F. oxysporum f. sp. fragariae, the cause of Fusarium wilt of strawberry, with isolates from four continents. We observed two distinct syndromes: one included chlorosis ('yellows-fragariae') and the other did not ('wilt-fragariae'). All yellows-fragariae isolates carried a predicted pathogenicity chromosome, 'chrY-frag ', that was horizontally transferred at least four times. chrY-frag was associated with virulence on specific cultivars and encoded predicted effectors that were highly upregulated during infection. chrY-frag was not present in wilt-fragariae; isolates causing this syndrome evolved pathogenicity independently. All origins of F. oxysporum f. sp. fragariae occurred outside of the host's native range. Our data support the conclusion that HCT is widespread in F. oxysporum, but pathogenicity can also evolve independently. The absence of chrY-frag in wilt-fragariae suggests that multiple, distinct pathogenicity chromosomes can confer the same host specificity. The wild progenitors of cultivated strawberry (Fragaria × ananassa) did not co-evolve with this pathogen, yet we discovered several sources of genetic resistance.


Asunto(s)
Fragaria , Fusarium , Cromosomas , Fragaria/genética , Fusarium/genética , Enfermedades de las Plantas
5.
Pharmacol Res ; 163: 105336, 2021 01.
Artículo en Inglés | MEDLINE | ID: mdl-33276105

RESUMEN

Glioblastomas (GBMs), the most frequent and aggressive human primary brain tumours, have altered cell metabolism, and one of the strongest indicators of malignancy is an increase in choline compounds. Choline is also a selective agonist of some neuronal nicotinic acetylcholine receptor (nAChR) subtypes. As little is known concerning the expression of nAChR in glioblastoma cells, we analysed in U87MG human grade-IV astrocytoma cell line and GBM5 temozolomide-resistant glioblastoma cells selected from a cancer stem cell-enriched culture, molecularly, pharmacologically and functionally which nAChR subtypes are expressed and,whether choline and nicotine can affect GBM cell proliferation. We found that U87MG and GBM5 cells express similar nAChR subtypes, and choline and nicotine increase their proliferation rate and activate the anti-apoptotic AKT and pro-proliferative ERK pathways. These effects are blocked by the presence of non-cell-permeable peptide antagonists selective for α7- and α9-containing nicotinic receptors. siRNA-mediated silencing of α7 or α9 subunit expression also selectively prevents the effects of nicotine and choline on GBM cell proliferation. Our findings indicate that nicotine and choline activate the signalling pathways involved in the proliferation of GBM cells, and that these effects are mediated by α7 and α9-containing nAChRs. This suggests that these nicotinic receptors may contribute to the aggressive behaviour of this tumor and may indicate new therapeutic strategies against high-grade human brain tumours.


Asunto(s)
Neoplasias Encefálicas/metabolismo , Colina/farmacología , Glioblastoma/metabolismo , Nicotina/farmacología , Receptores Nicotínicos/metabolismo , Receptor Nicotínico de Acetilcolina alfa 7/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Humanos , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Proteínas Proto-Oncogénicas c-akt/metabolismo , ARN Interferente Pequeño/genética , Receptores Nicotínicos/genética , Receptor Nicotínico de Acetilcolina alfa 7/genética
6.
Phytopathology ; 111(7): 1064-1079, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-33200960

RESUMEN

Scientific communication is facilitated by a data-driven, scientifically sound taxonomy that considers the end-user's needs and established successful practice. In 2013, the Fusarium community voiced near unanimous support for a concept of Fusarium that represented a clade comprising all agriculturally and clinically important Fusarium species, including the F. solani species complex (FSSC). Subsequently, this concept was challenged in 2015 by one research group who proposed dividing the genus Fusarium into seven genera, including the FSSC described as members of the genus Neocosmospora, with subsequent justification in 2018 based on claims that the 2013 concept of Fusarium is polyphyletic. Here, we test this claim and provide a phylogeny based on exonic nucleotide sequences of 19 orthologous protein-coding genes that strongly support the monophyly of Fusarium including the FSSC. We reassert the practical and scientific argument in support of a genus Fusarium that includes the FSSC and several other basal lineages, consistent with the longstanding use of this name among plant pathologists, medical mycologists, quarantine officials, regulatory agencies, students, and researchers with a stake in its taxonomy. In recognition of this monophyly, 40 species described as genus Neocosmospora were recombined in genus Fusarium, and nine others were renamed Fusarium. Here the global Fusarium community voices strong support for the inclusion of the FSSC in Fusarium, as it remains the best scientific, nomenclatural, and practical taxonomic option available.


Asunto(s)
Fusarium , Fusarium/genética , Filogenia , Enfermedades de las Plantas , Plantas
7.
Plant Dis ; 105(12): 3880-3888, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34232056

RESUMEN

Fusarium circinatum, the causal agent of pitch canker in pines and a cryptic endophyte of grasses, was examined for heritable variation in tolerance of the grass defense compound 2-benzoxazolinone (BOA). A diverse population of F. circinatum progeny was assayed for growth rate on potato dextrose agar amended with BOA. Matings were conducted to allow for selection of progeny with lower and higher tolerance of BOA. The results confirmed heritable variation in BOA tolerance in F. circinatum. A subset of differentially tolerant progeny was used for inoculations of growth chamber-grown Zea mays and greenhouse-grown Pinus radiata. No differences were detected in the rate of infection or extent of colonization of Z. mays inoculated with F. circinatum progeny differing in tolerance of BOA. Pitch canker symptoms in inoculated P. radiata trees showed that high BOA-tolerating isolates induced significantly longer lesion lengths than those induced by low BOA-tolerating isolates. Results from this study were consistent with the proposition that F. circinatum evolved from grass-colonizing ancestors and that pathogenicity to pine is a relatively recent evolutionary innovation.


Asunto(s)
Pinus , Poaceae , Benzoxazoles , Fusarium , Enfermedades de las Plantas
8.
Plant Dis ; 105(4): 912-918, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33135994

RESUMEN

Fusarium oxysporum f. sp. lactucae, the cause of Fusarium wilt of lettuce, can survive on crop residue in soil. Persistence of the pathogen over time will be influenced by the rate at which residue decomposes. We evaluated the effect of drying and fragmenting crop residue on the rate of decomposition and survival of F. oxysporum f. sp. lactucae. In a controlled experiment that represented optimal drying conditions, fragmenting and oven drying infested lettuce taproots at 30°C significantly reduced the frequency of recovery of the pathogen, compared with untreated tissue. However, in a field experiment, drying infested crop residue on the soil surface prior to incorporation did not significantly reduce survival of F. oxysporum f. sp. lactucae after 1 year. Regardless of treatment, there was not a significant decrease in soil inoculum density between 1 and 12 months after residue was incorporated. In a greenhouse experiment, fragmenting crop residue prior to incorporation in pathogen-free soil resulted in significantly higher inoculum densities of F. oxysporum f. sp. lactucae after 1 year. The increase in inoculum levels was associated with a faster rate of residue decomposition, which may be beneficial in the long run but not where lettuce will be replanted within the next year.


Asunto(s)
Fusarium , Lactuca , Suelo , Microbiología del Suelo
9.
Plant Dis ; 105(2): 264-267, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-32791882

RESUMEN

Fusarium oxysporum f. sp. mori, the causal agent of Fusarium wilt of blackberry, was first reported in California and Mexico in 2016. A limited survey of the population revealed this pathogen to be one of the most diverse formae speciales of F. oxysporum. We explored the possibility that strains of F. oxysporum pathogenic to commercial blackberry could also be recovered from wild blackberry (Rubus spp.) in California. For this purpose, wild Rubus species in blackberry nurseries, fruit production fields, and nearby areas were collected between 2017 and 2019. Thirty-four isolates of F. oxysporum were recovered from asymptomatic Rubus armeniacus and Rubus ursinus plants. Based on sequence of the translation elongation factor 1-α, somatic compatibility, and pathogenicity to blackberry, 16 isolates were confirmed as F. oxysporum f. sp. mori. These isolates were associated with three somatic compatibility groups, one of which was first identified in this study. Recovery of the pathogen confirmed that wild blackberry plants can act as a reservoir of inoculum of F. oxysporum f. sp. mori and that it can move from wild blackberry plants to commercial cultivars or vice versa.


Asunto(s)
Fusarium , Rubus , California , México , Enfermedades de las Plantas
10.
J Neurochem ; 154(2): 158-176, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-31967330

RESUMEN

Adrenal chromaffin cells release neurotransmitters in response to stress and may be involved in conditions such as post-traumatic stress and anxiety disorders. Neurotransmitter release is triggered, in part, by activation of nicotinic acetylcholine receptors (nAChRs). However, despite decades of use as a model system for studying exocytosis, the nAChR subtypes involved have not been pharmacologically identified. Quantitative real-time PCR of rat adrenal medulla revealed an abundance of mRNAs for α3, α7, ß2, and ß4 subunits. Whole-cell patch-clamp electrophysiology of chromaffin cells and subtype-selective ligands were used to probe for nAChRs derived from the mRNAs found in adrenal medulla. A novel conopeptide antagonist, PeIA-5469, was created that is highly selective for α3ß2 over other nAChR subtypes heterologously expressed in Xenopus laevis oocytes. Experiments using PeIA-5469 and the α3ß4-selective α-conotoxin TxID revealed that rat adrenal medulla contain two populations of chromaffin cells that express either α3ß4 nAChRs alone or α3ß4 together with the α3ß2ß4 subtype. Conclusions were derived from observations that acetylcholine-gated currents in some cells were sensitive to inhibition by PeIA-5469 and TxID, while in other cells, currents were sensitive only to TxID. Expression of functional α7 nAChRs was determined using three α7-selective ligands: the agonist PNU282987, the positive allosteric modulator PNU120596, and the antagonist α-conotoxin [V11L,V16D]ArIB. The results of these studies identify for the first time the expression of α3ß2ß4 nAChRs as well as functional α7 nAChRs by rat adrenal chromaffin cells.


Asunto(s)
Médula Suprarrenal/metabolismo , Células Cromafines/metabolismo , Antagonistas Nicotínicos/farmacología , Receptores Nicotínicos/biosíntesis , Animales , Células Cultivadas , Conotoxinas/farmacología , Masculino , Ratas , Ratas Sprague-Dawley , Xenopus laevis , Receptor Nicotínico de Acetilcolina alfa 7/antagonistas & inhibidores , Receptor Nicotínico de Acetilcolina alfa 7/biosíntesis
11.
Plant Dis ; 104(6): 1811-1816, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32282277

RESUMEN

Fusarium wilt of lettuce, caused by Fusarium oxysporum f. sp. lactucae, is now found in all major lettuce producing regions in California and Arizona. The population structure of F. oxysporum f. sp. lactucae in California and Arizona was characterized based on somatic compatibility and sequences of the translation elongation factor 1-α gene (EF-1α) and rDNA intergenic spacer region (IGS). In this study, 170 isolates were tested for somatic compatibility based on heterokaryon formation, using complementary nitrate nonutilizing (nit) mutants. Five subgroups (A to E) of somatic compatibility group 0300 were identified. Isolates associated with the same subgroup had a strong complementation reaction, whereas reactions between isolates of different subgroups were weak or delayed. An isolate from the first known infestation of Fusarium wilt of lettuce in California was associated with subgroup A, which predominated among isolates in our collection. Isolates representative of each subgroup were confirmed to be associated with race 1, based on the reaction of differential lettuce cultivars. It is possible that somatic compatibility subgroups B to E of F. oxysporum f. sp. lactucae were derived from subgroup A, as a consequence of somatic mutations affecting compatibility. If so, subgroups of F. oxysporum f. sp. lactucae may represent an intermediate step in divergence that will lead to clearly separable compatibility groups. Sequences of EF-1α and IGS were both identical for 58 isolates of F. oxysporum f. sp. lactucae that represented all somatic compatibility subgroups and locations from which isolates were obtained, indicating that subgroups were derived from the same clonal lineage (VCG 0300).


Asunto(s)
Fusarium , Arizona , California , ADN Ribosómico , Lactuca
12.
Plant Dis ; 104(1): 194-197, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31725344

RESUMEN

At Point Reyes National Seashore in California, Fusarium circinatum, the causal agent of pitch canker in pines, was isolated from Pinus muricata, the California native grass, Bromus carinatus, and the introduced grass, Holcus lanatus. All grass plants from which F. circinatum was isolated were symptomless. Pathogenicity of grass isolates was confirmed by inoculation of P. radiata trees, which developed symptoms similar to trees inoculated with a pine isolate of F. circinatum. Isolates from grasses were somatically compatible with isolates recovered from symptomatic pines. B. carinatus grown in a growth chamber was inoculated with a green fluorescent protein-expressing strain of F. circinatum. Segments of inoculated leaves were incubated in moist chambers; after 1 to 2 days, sporulating hyphae were observed growing from leaf tissue. Spores of F. circinatum removed from B. carinatus leaves were confirmed to be fluorescent when illuminated with ultraviolet light. These results raise the possibility that B. carinatus cryptically infected by F. circinatum may be a source of propagules capable of infecting pines.


Asunto(s)
Bromus , Fusarium , Enfermedades de las Plantas , Bromus/microbiología , California , Fusarium/fisiología , Pinus/microbiología , Enfermedades de las Plantas/microbiología , Poaceae/microbiología , Esporas Fúngicas
13.
Plant Dis ; 104(3): 772-779, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31967508

RESUMEN

Loss of water that reduces the relative water content (RWC) of bark can occur during processing, cold storage, and planting of bare-root stone fruit trees. In California nurseries and newly planted orchards, this stress can predispose young almond trees (Prunus dulcis) to a canker disease caused primarily by Fusarium species. While reduced bark RWC contributes to disease development, anecdotal observations suggest a seasonal effect on host physiology may also influence disease severity. We evaluated the effect of season and the impact of drying and reduced RWC on susceptibility of almond branch segments excised from orchard trees (cv. Nonpareil) to Fusarium acuminatum, Fusarium avenaceum, Fusarium brachygibbosum, and Fusarium californicum sp. nov. With lesion size as the criterion, excised inoculated branch segments were most susceptible in spring, of intermediate susceptibility during winter dormancy, and least susceptible during summer and fall. Consistent with an earlier study, branches with RWC between 80 and 85% yielded lesions that were significantly larger than lesions from branches with bark that was above or below that range. However, the effect of reduced bark moisture on lesion size was only apparent in the spring. These results affirm the importance of avoiding conditions that diminish moisture status in bare-root almond trees in Fusarium canker disease management, especially during transport and planting operations in the spring, a period of high physiological vulnerability. California nurseries apply fungicides to bare-root trees prior to cold storage to reduce "mold" growth. Of eight fungicides currently registered for use on almond trees, fludioxonil (Scholar), fluopyram/trifloxystrobin (Luna Sensation), and fluxapyroxad/pyraclostrobin (Merivon) were most inhibitory to in vitro mycelial growth of F. acuminatum, F. avenaceum, and F. brachygibbosum. However, our almond branch disease assay did not demonstrate preventive or curative fungicide action against infections by F. acuminatum or F. avenaceum.


Asunto(s)
Fusarium , Prunus dulcis , California , Estaciones del Año , Árboles
14.
J Sch Nurs ; 36(2): 144-156, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-30033842

RESUMEN

Half of U.S. states measure students' body mass index (BMI), with many communicating that information to parents through a "BMI report card" or notification letter. School nurses are usually responsible for implementing these programs and communicating results to parents. The purpose of this study was to understand parents' perceptions of BMI screening programs to help inform school nurses about messages that are most helpful to use in report cards to motivate parents to follow-up with a health-care provider or to make behavioral changes for their child. Using a cluster analysis and perceptual mapping methods, a commercial marketing technique that creates three-dimensional graphic maps, we identified four unique clusters of parents based on their core attitudes and beliefs related to BMI screenings and report cards. Based on vector modeling techniques, key message strategies were developed that can be used by school nurses to enhance parent response to a BMI report card.


Asunto(s)
Índice de Masa Corporal , Comunicación en Salud/métodos , Tamizaje Masivo , Padres/psicología , Servicios de Enfermería Escolar , Adolescente , Adulto , Análisis por Conglomerados , Estudios Transversales , Femenino , Humanos , Imagenología Tridimensional , Masculino , Persona de Mediana Edad , Modelos Teóricos , Philadelphia/epidemiología
15.
Phytopathology ; 109(5): 770-779, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-30644330

RESUMEN

Asymptomatic plant colonization is hypothesized to enhance persistence of pathogenic forms of Fusarium oxysporum. However, a correlation between pathogen populations on living, asymptomatic plant tissues and soilborne populations after tillage has not been demonstrated. Living and dead tissues of broccoli, lettuce, spinach, wheat, cilantro, raspberry, and strawberry plants grown in soil infested with F. oxysporum f. sp. fragariae (the cause of Fusarium wilt of strawberry) were assayed to quantify the incidence of infection and extent of colonization by this pathogen. All crops could be infected by F. oxysporum f. sp. fragariae but the extent of colonization varied between plant species. Pathogen population densities on nonliving crown tissues incorporated into the soil matrix were typically greater than those observed on living tissues. Crop-dependent differences in the inoculum density of F. oxysporum f. sp. fragariae in soil were only observed after decomposition of crop residue. Forty-four weeks after plants were incorporated into the soil, F. oxysporum f. sp. fragariae soil population densities were positively correlated with population densities on plant tissue fragments recovered at the same time point. Results indicate that asymptomatic colonization can have a significant, long-term impact on soilborne populations of Fusarium wilt pathogens. Cultural practices such as crop rotation should be leveraged to favor pathogen population decline by planting hosts that do not support extensive population growth on living or decomposing tissues.


Asunto(s)
Productos Agrícolas/microbiología , Fusarium/crecimiento & desarrollo , Enfermedades de las Plantas/microbiología , Microbiología del Suelo , Agricultura/métodos , Fusarium/patogenicidad
16.
Proc Natl Acad Sci U S A ; 113(15): 3966-71, 2016 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-27035977

RESUMEN

Photocatalytic pathways could prove crucial to the sustainable production of fuels and chemicals required for a carbon-neutral society. Electron-hole recombination is a critical problem that has, so far, limited the efficiency of the most promising photocatalytic materials. Here, we show the efficacy of anisotropy in improving charge separation and thereby boosting the activity of a titania (TiO2) photocatalytic system. Specifically, we show that H2 production in uniform, one-dimensional brookite titania nanorods is highly enhanced by engineering their length. By using complimentary characterization techniques to separately probe excited electrons and holes, we link the high observed reaction rates to the anisotropic structure, which favors efficient carrier utilization. Quantum yield values for hydrogen production from ethanol, glycerol, and glucose as high as 65%, 35%, and 6%, respectively, demonstrate the promise and generality of this approach for improving the photoactivity of semiconducting nanostructures for a wide range of reacting systems.

17.
Plant Dis ; 103(7): 1498-1506, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-31059386

RESUMEN

Seven lettuce cultivars were transplanted into a field infested with Fusarium oxysporum f. sp. lactucae (causal agent of Fusarium wilt of lettuce) in August and September of 2014, 2015, and 2016. For moderately susceptible cultivars, 1- or 2-week differences in planting date had a significant effect on severity of Fusarium wilt. In growth chamber experiments, cultivars of moderate susceptibility were maintained in a growth chamber under cool conditions (23/18°C), and a subset of plants was transferred to a warm chamber (33/23°C) for 1 week, at weekly intervals after transplanting. Plants exposed to high temperatures at 2 and 3 weeks after transplanting (WAT) had more severe symptoms of Fusarium wilt than those exposed at 4 WAT. In October 2015, April 2016, August 2016, and August 2017, moderately susceptible cultivars were planted into field soil with an inoculum density gradient. Moderately susceptible cultivars were little affected by Fusarium wilt where inoculum densities of F. oxysporum f. sp. lactucae were <125 per gram of soil, even in warm planting windows. Adjusting planting dates to avoid high temperatures during a critical stage of growth and maintaining low inoculum density in soil can contribute to management of Fusarium wilt in moderately susceptible lettuce cultivars.


Asunto(s)
Fusarium , Lactuca , Microbiología del Suelo , California , Fusarium/fisiología , Lactuca/microbiología , Enfermedades de las Plantas/microbiología , Estaciones del Año , Temperatura
18.
Plant Dis ; 103(5): 1006-1013, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-30946629

RESUMEN

Isolates of the Fusarium oxysporum species complex have been characterized as plant pathogens that commonly cause vascular wilt, stunting, and yellowing of the leaves in a variety of hosts. F. oxysporum species complex isolates have been grouped into formae speciales based on their ability to cause disease on a specific host. F. oxysporum f. sp. fragariae is the causal agent of Fusarium wilt of strawberry and has become a threat to production as fumigation practices have changed in California. F. oxysporum f. sp. fragariae is polyphyletic and limited genetic markers are available for its detection. In this study, next-generation sequencing and comparative genomics were used to identify a unique genetic locus that can detect all of the somatic compatibility groups of F. oxysporum f. sp. fragariae identified in California. This locus was used to develop a TaqMan quantitative polymerase chain reaction assay and an isothermal recombinase polymerase amplification (RPA) assay that have very high sensitivity and specificity for more than 180 different isolates of the pathogen tested. RPA assay results from multiple field samples were validated with pathogenicity tests of recovered isolates.


Asunto(s)
Fragaria , Fusarium , Filogenia , California , Fragaria/microbiología , Fusarium/genética , Fusarium/fisiología , Genes Fúngicos/genética , Enfermedades de las Plantas/microbiología
19.
AIDS Care ; 28(4): 528-36, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-26572215

RESUMEN

Minority participation in HIV clinical trials research is critical to understanding the impact of medications or behavioral interventions, but little is known about gender differences in perceptions of participation. We surveyed 50 minority HIV+ patients from an urban clinic to assess perceived risks/benefits of clinical trial research participation and used innovative marketing methods to analyze results. Perceptual mapping and vector message-modeling, a method that creates 3-D models representing how groups conceptualize elements, were used to assess how male and female participants could be motivated to participate. Results showed men farther away from participation and more concerned with HIV disclosure and experimentation than women. Men expressed distrust of the medical system, doubted HIV's origin, and knew less about research implementation. Women were closer to participation in both behavior and medical trials and perceived medication issues as more significant, including fear of losing medication stability, medications not working, being in the placebo group, and experiencing side effects. Vector modeling shows that messages would need to focus on different aspects of clinical research for men and women and that interventions aimed at minority HIV+ patients to encourage clinical trial participation would need to be targeted to their unique perceptions. Understanding gender perceptions of HIV clinical research has significant implications for targeting messages to increase minority participation.


Asunto(s)
Ensayos Clínicos como Asunto/psicología , Barreras de Comunicación , Infecciones por VIH/psicología , Seropositividad para VIH/epidemiología , Grupos Minoritarios , Factores Sexuales , Adolescente , Adulto , Anciano , Femenino , Grupos Focales , Infecciones por VIH/etnología , Conocimientos, Actitudes y Práctica en Salud/etnología , Humanos , Masculino , Persona de Mediana Edad , Motivación , Aceptación de la Atención de Salud/etnología , Percepción , Estigma Social , Encuestas y Cuestionarios , Confianza , Estados Unidos/epidemiología , Población Urbana , Adulto Joven
20.
BMC Public Health ; 16: 413, 2016 05 17.
Artículo en Inglés | MEDLINE | ID: mdl-27184052

RESUMEN

BACKGROUND: Research suggests that men are less likely to seek help for depression, substance abuse, and stressful life events due to negative perceptions of asking for and receiving help. This may be exacerbated in male military cadets who exhibit higher levels of gender role conflict because of military culture. METHODS: This exploratory study examined the perceptions of 78 male military cadets toward help-seeking behaviors. Cadets completed the 31-item Barriers to Help Seeking Scale (BHSS) and a component factor analysis was used to generate five composite variables and compare to validated factors. Perceptual mapping and vector modeling, which produce 3-dimensional models of a group's perceptions, were then used to model how they conceptualize help-seeking. RESULTS: Factor analysis showed slightly different groupings than the BHSS, perhaps attributed to different characteristics of respondents, who are situated in a military school compared to general university males. Perceptual maps show that cadets perceive trust of doctors closest to them and help-seeking farthest, supporting the concept that these males have rigid beliefs about having control and its relationship to health seeking. Differences were seen when comparing maps of White and non-White cadets. White cadets positioned themselves far away from all variables, while non-White cadets were closest to "emotional control". CONCLUSION: To move these cadets toward help-seeking, vector modeling suggests that interventions should focus on their general trust of doctors, accepting lack of control, and decreasing feelings of weakness when asking for help. For non-White cadets a focus on self-reliance may also need to be emphasized. Use of these unique methods resulted in articulation of specific barriers that if addressed early, may have lasting effects on help-seeking behavior as these young men become adults. Future studies are needed to develop and test specific interventions to promote help-seeking among military cadets.


Asunto(s)
Intención , Personal Militar/psicología , Aceptación de la Atención de Salud/psicología , Universidades , Adolescente , Depresión/psicología , Depresión/terapia , Identidad de Género , Humanos , Masculino , Estrés Psicológico/psicología , Estrés Psicológico/terapia , Trastornos Relacionados con Sustancias/psicología , Trastornos Relacionados con Sustancias/terapia , Adulto Joven
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