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2.
Pestic Biochem Physiol ; 201: 105881, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38685247

RESUMEN

Insect pests cause immense agronomic losses worldwide. One of the most destructive of major crops is the Fall Armyworm (Spodoptera frugiperda, FAW). The ability to migrate long distances, a prodigious appetite, and a demonstrated ability to develop resistance to insecticides, make it a difficult target to control. Insecticidal proteins, for example those produced by the bacterium Bacillus thuringiensis, are among the safest and most effective insect control agents. Genetically modified (GM) crops expressing such proteins are a key part of a successful integrated pest management (IPM) program for FAW. However, due to the development of populations resistant to commercialized GM products, new GM traits are desperately needed. Herein, we describe a further characterization of the newly engineered trait protein eCry1Gb.1Ig. Similar to other well characterized Cry proteins, eCry1Gb.1Ig is shown to bind FAW midgut cells and induce cell-death. Binding competition assays using trait proteins from other FAW-active events show a lack of competition when binding FAW brush border membrane vesicles (BBMVs) and when utilizing non-pore-forming versions as competitors in in vivo bioassays. Similarly, insect cell lines expressing SfABCC2 and SfABCC3 (well characterized receptors of existing commercial Cry proteins) are insensitive to eCry1Gb.1Ig. These findings are consistent with results from our previous work showing that eCry1Gb.1Ig is effective in controlling insects with resistance to existing traits. This underscores the value of eCry1Gb.1Ig as a new GM trait protein with a unique site-of-action and its potential positive impact to global food production.


Asunto(s)
Proteínas Bacterianas , Spodoptera , Animales , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/genética , Proteínas Hemolisinas/farmacología , Proteínas Hemolisinas/metabolismo , Proteínas Hemolisinas/genética , Endotoxinas/farmacología , Endotoxinas/metabolismo , Toxinas de Bacillus thuringiensis/farmacología , Bacillus thuringiensis/genética , Bacillus thuringiensis/metabolismo , Insecticidas/farmacología , Plantas Modificadas Genéticamente , Control Biológico de Vectores/métodos
3.
Front Endocrinol (Lausanne) ; 15: 1297164, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38505746

RESUMEN

Background: Syndrome of inappropriate antidiuretic(SIAD) occurs secondary to various diseases, which is characterised by hypotonic hyponatremia and impaired urinary diluting capacity. Research on SIAD in both domestic and international contexts has a long history. This study objectively and comprehensively analyses the research trends, hotspots and development of SIAD research of the past 20 years using the method of bibliometric analysis. Methods: The 2003-2022 data in the Web of Science Core Collection database were searched. The Bibliometrix software package, VOSviewer and CiteSpace were used to mine, extract and visualise the retrieved literature, and the generated maps were used in analysing the main topics and trends in the field of SIAD research. Results: A total of 1215 articles published in 623 journals were included in the analysis, with a total of 18,886 citations. Results showed that the research output on SIAD has continuously increased in the past 20 years, and the United States had the highest number of publications and citations. Keywords with the highest burst strength in recent years were the most mentioned keywords, in addition to the search terms 'hyponatremia', 'covid-19', and 'mortality'. Thus, the relationship among SIAD, covid-19 and mortality may become research frontiers and trends. Fifteen milestone articles were identified through co-citation analysis, which mainly focused on the pathophysiology and treatment of SIAD. Conclusion: Based on bibliometric analysis and knowledge mapping, this study summarises development trends in the field of SIAD research, providing references for current and future research into SIAD.


Asunto(s)
COVID-19 , Hiponatremia , Humanos , Bibliometría , COVID-19/epidemiología , Bases de Datos Factuales , Conocimiento
4.
Ital J Pediatr ; 50(1): 12, 2024 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-38263086

RESUMEN

BACKGROUND: Lung ultrasound (LUS) is recommended as a reliable diagnostic alternative to chest X-ray (CXR) for detecting pneumonia in children. METHODS: PubMed, Embase, and Cochrane Library databases were used to identify eligible studies from their inception until April 2023. The investigated diagnostic parameters included sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and area under the receiver operating characteristic curves (AUC). RESULTS: Twenty-six studies involving 3,401 children were selected for meta-analysis. The sensitivity, specificity, PLR, NLR, DOR, and AUC of LUS for detecting pneumonia in children were 0.95, 0.92, 12.31, 0.05, 108.53, and 0.98, respectively, while the sensitivity, specificity, PLR, NLR, DOR, and AUC of CXR were 0.92, 0.93, 24.63, 0.08, 488.54, and 0.99, respectively. The sensitivity of LUS was higher than that of CXR for detecting pneumonia in children (ratio: 1.03; 95% CI: 1.01-1.06; P = 0.018), whereas the DOR of LUS was significantly lower than that of CXR (ratio: 0.22; 95% CI: 0.06-0.85; P = 0.028). CONCLUSIONS: This study found that the diagnostic performance of LUS was comparable to that of CXR for detecting pneumonia, and the sensitivity of LUS was superior to that of CXR.


Asunto(s)
Neumonía , Niño , Humanos , Radiografía , Ultrasonografía , Bases de Datos Factuales , Pulmón
5.
Front Endocrinol (Lausanne) ; 14: 1251718, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38116308

RESUMEN

A Chinese family was identified to have two patients with rickets, an adult female and a male child (proband), both exhibiting signs related to X-linked hypophosphatemic rickets (XLH). Gene sequencing analysis revealed a deletion of adenine at position 1985 (c.1985delA) in the PHEX-encoding gene. To investigate the relationship between this mutation and the pathogenicity of XLH, as well as analyze the effects of different dosages of PHEX gene mutations on clinical phenotypes, we developed a rat model carrying the PHEX deletion mutation. The CRISPR/Cas9 gene editing technology was employed to construct the rat model with the PHEX gene mutation (c.1985delA). Through reproductive procedures, five genotypes of rats were obtained: female wild type (X/X), female heterozygous (-/X), female homozygous wild type (-/-), male wild type (X/Y), and male hemizygous (-/Y). The rats with different genotypes underwent analysis of growth, serum biochemical parameters, and bone microstructure. The results demonstrated the successful generation of a stable rat model inheriting the PHEX gene mutation. Compared to the wild-type rats, the mutant rats displayed delayed growth, shorter femurs, and significantly reduced bone mass. Among the female rats, the homozygous individuals exhibited the smallest body size, decreased bone mass, shortest femur length, and severe deformities. Moreover, the mutant rats showed significantly lower blood phosphorus concentration, elevated levels of FGF23 and alkaline phosphatase, and increased expression of phosphorus regulators. In conclusion, the XLH rat model with the PHEX gene mutation dosage demonstrated its impact on growth and development, serum biochemical parameters, and femoral morphology.


Asunto(s)
Raquitismo Hipofosfatémico Familiar , Animales , Femenino , Masculino , Ratas , Raquitismo Hipofosfatémico Familiar/genética , Raquitismo Hipofosfatémico Familiar/diagnóstico , Genotipo , Mutación , Linaje , Endopeptidasa Neutra Reguladora de Fosfato PHEX/genética , Fósforo
6.
J Am Stat Assoc ; 118(541): 3-17, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37153845

RESUMEN

Over the past 30 years, magnetic resonance imaging has become a ubiquitous tool for accurately visualizing the change and development of the brain's subcortical structures (e.g., hippocampus). Although subcortical structures act as information hubs of the nervous system, their quantification is still in its infancy due to many challenges in shape extraction, representation, and modeling. Here, we develop a simple and efficient framework of longitudinal elastic shape analysis (LESA) for subcortical structures. Integrating ideas from elastic shape analysis of static surfaces and statistical modeling of sparse longitudinal data, LESA provides a set of tools for systematically quantifying changes of longitudinal subcortical surface shapes from raw structure MRI data. The key novelties of LESA include: (i) it can efficiently represent complex subcortical structures using a small number of basis functions and (ii) it can accurately delineate the spatiotemporal shape changes of the human subcortical structures. We applied LESA to analyze three longitudinal neuroimaging data sets and showcase its wide applications in estimating continuous shape trajectories, building life-span growth patterns, and comparing shape differences among different groups. In particular, with the Alzheimer's Disease Neuroimaging Initiative (ADNI) data, we found that the Alzheimer's Disease (AD) can significantly speed the shape change of ventricle and hippocampus from 60 to 75 years old compared with normal aging.

7.
Front Neurosci ; 16: 954055, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36117613

RESUMEN

It is well-known that morphological features in the brain undergo changes due to traumatic events and associated disorders such as post-traumatic stress disorder (PTSD). However, existing approaches typically offer group-level comparisons, and there are limited predictive approaches for modeling behavioral outcomes based on brain shape features that can account for heterogeneity in PTSD, which is of paramount interest. We propose a comprehensive shape analysis framework representing brain sub-structures, such as the hippocampus, amygdala, and putamen, as parameterized surfaces and quantifying their shape differences using an elastic shape metric. Under this metric, we compute shape summaries (mean, covariance, PCA) of brain sub-structures and represent individual brain shapes by their principal scores under a shape-PCA basis. These representations are rich enough to allow visualizations of full 3D structures and help understand localized changes. In order to validate the elastic shape analysis, we use the principal components (PCs) to reconstruct the brain structures and perform further evaluation by performing a regression analysis to model PTSD and trauma severity using the brain shapes represented via PCs and in conjunction with auxiliary exposure variables. We apply our method to data from the Grady Trauma Project (GTP), where the goal is to predict clinical measures of PTSD. The framework seamlessly integrates accurate morphological features and other clinical covariates to yield superior predictive performance when modeling PTSD outcomes. Compared to vertex-wise analysis and other widely applied shape analysis methods, the elastic shape analysis approach results in considerably higher reconstruction accuracy for the brain shape and reveals significantly greater predictive power. It also helps identify local deformations in brain shapes associated with PTSD severity.

8.
J Clin Lab Anal ; 35(5): e23760, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33724522

RESUMEN

BACKGROUND: Identifying new molecular diagnostic markers for Mycoplasma Pneumoniae Pneumonia (MPP) has always been an essential topic since MPP cases have increased every year, especially among children. Here, we examined the correlation between serum level of Purinergic receptor P2X7, vitamin A, and 25-hydroxy vitamin D (25(OH)D) and the severity of MPP, aiming to identify molecules that have the potential to become diagnostic markers. METHODS: This study was conducted on 186 cases aged 1-14 (136 MPP and 50 non-MPP patients). Serum levels of Purinergic receptor P2X7, vitamin A, 25(OH)D, and multiple inflammatory and immune factors were measured, compared, and tested for statistical significance. RESULTS: Serum P2X7, tumor necrosis factor-α (TNF-α), and interleukin-1ß (IL-1ß) levels were significantly increased in severe MPP patients, while serum vitamin A, 25(OH)D, IgA, and IgG levels were significantly decreased. CONCLUSION: Our results demonstrated a positive correlation between serum P2X7 level and the severity of MPP, and negative correlations between serum levels of vitamin A and 25(OH)D and the severity of MPP, suggesting that high serum levels of P2X7 and low serum levels of vitamin A and 25(OH)D may indicate relatively severer MPP.


Asunto(s)
Mycoplasma pneumoniae/fisiología , Neumonía por Mycoplasma/sangre , Neumonía por Mycoplasma/microbiología , Receptores Purinérgicos P2X7/sangre , Vitamina A/sangre , Vitamina D/análogos & derivados , Adolescente , Niño , Preescolar , Citocinas/sangre , Humanos , Inmunoglobulina G/sangre , Lactante , Mediadores de Inflamación/sangre , Modelos Logísticos , Análisis Multivariante , Vitamina D/sangre
9.
PLoS One ; 15(2): e0228277, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32027662

RESUMEN

Approximately 94% of the land area of the Northern Tibetan Plateau is covered by grasslands, which comprise one of five key livestock producing regions in China. In contrast to most other regions worldwide, these alpine grasslands are much more sensitive to global climate change, thus they are under intense study. The differences in species diversity, plant biomass, and soil properties of five representative's alpine grassland types in the Northern Tibetan Plateau were investigated in this research. The results revealed that 11 community types were identified according to the importance of dominant species and constructive species. There were significant differences in the Margalef index (H), Simpson diversity index (D), Shannon-wiener diversity index (H'), and Pielou evenness index (J) indices between these five alpine grasslands. Further, the above-ground biomass (AGB), below-ground biomass (BGB), total biomass (TB), root:shoot (R/S) ratio, and coverage showed significant differences in 5 alpine grasslands. There were also considerable variations in the pH, total nitrogen concentration (TN), total phosphorus concentration (TP), soil organic carbon (SOC) and C-to-N ratio (C:N) among the five alpine grasslands. The highest value of biomass and soil characteristics was always in the alpine steppe (AS), or AM, while the lowest of that was in the alpine desert steppe (ADS), or alpine desert (AD). Moreover, there were significant differences in the soil particle size fractions between the five alpine grasslands. In the AM and AS, the dominant soil particle was clay, while in the alpine meadow-steppe (AMS), ADS, and AD it was fine and medium sand. Substantial correlations were found between the biomass and species diversity indices H, D or H' and soil TN, TP, or SOC. Moreover, silt had a significantly positive correlation with soil C:N, BGB, TB, and R/S, while medium sand and coarse sand was significant negatively correlated. With regard to these grassland types, it is proposed that the AM or AS may be an actively changing grassland types in the Northern Tibetan Plateau.


Asunto(s)
Biodiversidad , Biomasa , Pradera , Suelo/química , Concentración de Iones de Hidrógeno , Nitrógeno/análisis , Raíces de Plantas/fisiología , Brotes de la Planta/fisiología , Plantas/química , Plantas/metabolismo , Tibet
10.
GM Crops ; 1(4): 220-9, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-21844677

RESUMEN

In recent years, there has been a rapid increase in the planting of transgenic crops with stacked traits. Most of these products have been formed by conventional breeding, i.e. the crossing of transgenic plant (event) containing individual transgenes with other event(s) containing single or double transgenic traits. Many biotech companies are developing stacked trait products with increasing numbers of insect and herbicide tolerance genes for controlling a broad range of insect pests and weeds. There has also been an increase in development of technologies for molecular stacking of multiple traits in a single transgene locus. In this review we look at the status of stacked trait products, crop trait stacking technologies and the technical challenges we are facing. We also review recent progress in developing technology for assembling large transgene arrays in vitro (molecular stacks), their delivery to crop plants and issues they pose for transgene expression.


Asunto(s)
Productos Agrícolas/genética , Plantas Modificadas Genéticamente/genética , Transgenes/genética , Animales , Cruzamiento , Productos Agrícolas/parasitología , Resistencia a la Enfermedad/genética , Gossypium/genética , Gossypium/parasitología , Insectos/crecimiento & desarrollo , Resistencia a los Insecticidas/genética , Plantas Modificadas Genéticamente/parasitología , Zea mays/genética , Zea mays/parasitología
11.
J Biol Chem ; 283(5): 2973-85, 2008 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-18048357

RESUMEN

The alpha(1a)-adrenergic receptor (alpha(1a)AR) occupies intracellular and plasma membranes in both native and heterologous expression systems. Based on multiple independent lines of evidence, we demonstrate the alpha(1a)AR at the cell surface occupies membrane rafts but exits from rafts following stimulation. In non-detergent raft preparations, basal alpha(1a)AR is present in low density membrane rafts and colocalizes with its G protein effectors on density gradients. Raft disruption by cholesterol depletion with methyl-beta-cyclodextrin eliminates these light rafts. To confirm the presence of the alpha(1a)AR in plasma membrane rafts, fluorescence resonance energy transfer measurements were used to demonstrate colocalization of surface receptor and the raft marker, cholera toxin B. This colocalization was largely lost following alpha(1a)AR stimulation with phenylephrine. Similarly, receptor stimulation causes exit of the alpha(1a)AR from light rafts within 3-10 min in contrast to the G proteins, which largely remain in light rafts. Importantly, this delayed exit of the alpha(1a)AR suggests acute receptor signaling and desensitization occur entirely within rafts. Interestingly, both confocal analysis and measurement of surface alpha(1a)AR levels indicate modest receptor internalization during the 10 min following stimulation, suggesting most of the receptor has entered non-raft plasma membrane. Nevertheless, activation does increase the rate of receptor internalization as does disruption of rafts with methyl-beta-cyclodextrin, suggesting raft exit enables internalization. Confocal analysis of surface-labeled hemagglutinin-alpha(1a)AR reveals that basal and stimulated receptor occupies clathrin pits in fixed cells consistent with previous indirect evidence. The evidence presented here strongly suggests the alpha(1a)AR is a lipid raft protein under basal conditions and implies agonist-mediated signaling occurs from rafts.


Asunto(s)
Invaginaciones Cubiertas de la Membrana Celular/metabolismo , Proteínas de Unión al GTP/metabolismo , Microdominios de Membrana/metabolismo , Receptores Adrenérgicos alfa 1/metabolismo , Animales , Línea Celular , Toxina del Cólera/metabolismo , Colesterol/metabolismo , Transferencia Resonante de Energía de Fluorescencia , Humanos , Microdominios de Membrana/efectos de los fármacos , Fenilefrina/farmacología , Ratas , Receptores Adrenérgicos alfa 1/genética , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Transducción de Señal/efectos de los fármacos , beta-Ciclodextrinas/farmacología
12.
Methods ; 39(1): 43-9, 2006 May.
Artículo en Inglés | MEDLINE | ID: mdl-16793282

RESUMEN

Measurement of fluorescence recovery after photobleaching (FRAP) is a non-invasive technique for studying protein dynamics in real time in living cells. FRAP studies are carried out on proteins tagged with green fluorescent protein (GFP) or one of its spectral variants. Illumination with high intensity laser light irreversibly bleaches the GFP fluorescence but has no effect on protein function. By photobleaching a limited region of the cytoplasm, the rate of fluorescence recovery provides a measure of the rate of protein diffusion. A detailed description of the FRAP technique is given, including its application to measuring the mobility of GFP-tagged Sup35p in [psi(-)] and [PSI(+)] cells.


Asunto(s)
Citosol/metabolismo , Recuperación de Fluorescencia tras Fotoblanqueo/métodos , Priones/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Algoritmos , Difusión , Proteínas Fluorescentes Verdes/química , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Factores de Terminación de Péptidos , Priones/genética , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética
13.
Proc Natl Acad Sci U S A ; 102(36): 12789-94, 2005 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-16123122

RESUMEN

Propagation of the yeast prion [PSI+], a self-replicating aggregated form of Sup35p, requires Hsp104. One model to explain this phenomenon proposes that, in the absence of Hsp104, Sup35p aggregates enlarge but fail to replicate thus becoming diluted out as the yeast divide. To test this model, we used live imaging of Sup35p-GFP to follow the changes that occur in [PSI+] cells after the addition of guanidine to inactivate Hsp104. After guanidine addition there was initially an increase in aggregation of Sup35p-GFP; but then, before the yeast divided, the aggregates began to dissolve, and after approximately 6 h the Sup35-GFP looked identical to the Sup35-GFP in [psi+] cells. Although plating studies showed that the yeast were still [PSI+], this reduction in aggregation suggested that curing of [PSI+] by inactivation of Hsp104 might be independent of cell division. This was tested by measuring the rate of curing of [PSI+] cells in both dividing and nondividing cells. Cell division was inhibited by adding either alpha factor or farnesol. Remarkably, with both of these methods, we found that the rate of curing was not significantly affected by cell division. Thus, cell division is not a determining factor for curing [PSI+] by inactivating Hsp104 with guanidine. Rather, curing apparently occurs because Sup35-GFP polymers slowly depolymerize in the absence of Hsp104 activity. Hsp104 then counteracts this curing possibly by catalyzing formation of new polymers.


Asunto(s)
Guanidina/farmacología , Proteínas de Choque Térmico/metabolismo , Priones/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/efectos de los fármacos , Saccharomyces cerevisiae/metabolismo , División Celular/efectos de los fármacos , Proteínas de Choque Térmico/genética , Factores de Terminación de Péptidos , Priones/genética , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética
14.
Eukaryot Cell ; 4(2): 289-97, 2005 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-15701791

RESUMEN

The Saccharomyces cerevisiae [PSI+] prion is a misfolded form of Sup35p that propagates as self-replicating cytoplasmic aggregates. Replication is believed to occur through breakage of transmissible [PSI+] prion particles, or seeds, into more numerous pieces. In [PSI+] cells, large Sup35p aggregates are formed by coalescence of smaller sodium dodecyl sulfate-insoluble polymers. It is uncertain if polymers or higher-order aggregates or both act as prion seeds. A mutant Hsp70 chaperone, Ssa1-21p, reduces the number of transmissible [PSI+] seeds per cell by 10-fold but the overall amount of aggregated Sup35p by only two- to threefold. This discrepancy could be explained if, in SSA1-21 cells, [PSI+] seeds are larger or more of the aggregated Sup35p does not function as a seed. To visualize differences in aggregate size, we constructed a Sup35-green fluorescent protein (GFP) fusion (NGMC) that has normal Sup35p function and can propagate like [PSI+]. Unlike GFP fusions lacking Sup35p's essential C-terminal domain, NGMC did not form fluorescent foci in log-phase [PSI+] cells. However, using fluorescence recovery after photobleaching and size fractionation techniques, we find evidence that NGMC is aggregated in these cells. Furthermore, the aggregates were larger in SSA1-21 cells, but the size of NGMC polymers was unchanged. Possibly, NGMC aggregates are bigger in SSA1-21 cells because they contain more polymers. Our data suggest that Ssa1-21p interferes with disruption of large Sup35p aggregates, which lack or have limited capacity to function as seed, into polymers that function more efficiently as [PSI+] seeds.


Asunto(s)
Adenosina Trifosfatasas/metabolismo , Proteínas HSP70 de Choque Térmico/metabolismo , Priones/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/fisiología , Adenosina Trifosfatasas/genética , Fraccionamiento Celular , Recuperación de Fluorescencia tras Fotoblanqueo , Proteínas HSP70 de Choque Térmico/genética , Factores de Terminación de Péptidos , Priones/genética , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Proteínas de Saccharomyces cerevisiae/genética
15.
Phytopathology ; 94(6): 584-92, 2004 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-18943483

RESUMEN

ABSTRACT We reported previously that physiological leaf spot (PLS) formation in winter and spring barley is dependent on genotype-related oxidative stress under field conditions. In the present study, we searched for factors inducing PLS symptoms in the greenhouse similar to those observed in the field and investigated its relationship to reactive oxygen species (ROS) metabolism. We found that in the greenhouse, oxidative stress induced spring barley cv. Extract, which is sensitive to PLS, to express symptoms similar to those observed in the field. Leaves severely affected by PLS showed significantly lower activities of key enzymes in the Halliwell-Asada cycle such as ascorbate peroxidase, glutathione reductase, dehy-droascorbate reductase, and monodehydroascorbate reductase. The sensitive cultivar also showed lower levels of total superoxide dismutase (SOD) and Cu/Zn-SOD activity but a higher level of chloroplast-specific Fe-SOD activity than that of the insensitive cultivar. Thus, an unbalanced ROS metabolism in chloroplasts may trigger PLS incidence in sensitive cultivars, which is in agreement with the fact that light is essential for the induction of PLS expression under both field and greenhouse conditions. Accordingly, under greenhouse conditions, continuous light stress (7 days), but not light shock treatments, induced PLS similar to that of field conditions in sensitive cv. Extract, but not in resistant cv. Scarlett. Light with a high proportion of energy in the blue wavelength spectrum (350 to 560 nm) was significantly more PLS inductive than light with a pronounced red (photosynthetically active radiation) spectrum (580 to 650 nm). Exposure to ozone did not produce PLS-like symptoms. Furthermore, similar to earlier observations in the field, PLS symptom expression was closely correlated with the accumulation of superoxide (O(2) (-)) detected by both biochemical and histochemical assays. Taken together, these data suggest that PLS in barley is genotype-dependent but its expression appears to be induced by certain environmental stress factors, among which photosyn-thetically active radiation plays a major role.

16.
Environ Pollut ; 116(1): 37-47, 2002.
Artículo en Inglés | MEDLINE | ID: mdl-11808554

RESUMEN

Two modern fungicides, a strobilurin, azoxystrobin (AZO), and a triazole, epoxiconazole (EPO), applied as foliar spray on spring barley (Hordeum vulgare L. cv. Scarlett) 3 days prior to fumigation with injurious doses of ozone (150-250 ppb; 5 days; 7 h/day) induced a 50-60% protection against ozone injury on leaves. Fungicide treatments of barley plants at growth stage (GS) 32 significantly increased the total leaf soluble protein content. Additionally, activities of the antioxidative enzymes superoxide dismutase (SOD), catalase (CAT), ascorbate-peroxidase (APX) and glutathione reductase (GR) were increased by both fungicides at maximal rates of 16, 75, 51 and 144%, respectively. Guiacol-peroxidase (POX) activity was elevated by 50-110% only in AZO treated plants, while this effect was lacking after treatments with EPO. This coincided with elevated levels of hydrogen peroxide (H2O2) only in EPO and not in AZO treated plants. The enhancement of the plant antioxidative system by the two fungicides significantly and considerably reduced the level of superoxide (O2*-) in leaves. Fumigation of barley plants for 4 days with non-injurious ozone doses (120-150 ppb, 7 h/day) markedly and immediately stimulated O2*- accumulation in leaves, while H2O2 was increased only after the third day of fumigation. Therefore, O2*- itself or as precursor of even more toxic oxyradicals appears to be more indicative for ozone-induced leaf damage than H2O2. Ozone also induced significant increases in the activity of antioxidant enzymes (SOD, POX and CAT) after 2 days of fumigation in fungicide untreated plants, while after 4 days of fumigation these enzymes declined to a level lower than in unfumigated plants, due to the oxidative degradation of leaf proteins. This is the first report demonstrating the marked enhancement of plant antioxidative enzymes and the enhanced scavenging of potentially harmful O2*- by fungicides as a mechanism of protecting plants against noxious oxidative stress from the environment. The antioxidant effect of modern fungicides widely used in intense cereal production in many countries represents an important factor when evaluating potential air pollution effects in agriculture.


Asunto(s)
Acrilatos/efectos adversos , Antioxidantes/farmacología , Exposición a Riesgos Ambientales , Compuestos Epoxi/efectos adversos , Fungicidas Industriales/efectos adversos , Hordeum/fisiología , Oxidantes Fotoquímicos/efectos adversos , Ozono/efectos adversos , Pirimidinas/efectos adversos , Especies Reactivas de Oxígeno , Triazoles/efectos adversos , Inducción Enzimática , Metacrilatos , Estrés Oxidativo , Hojas de la Planta/enzimología , Estrobilurinas
17.
Phytopathology ; 92(2): 145-55, 2002 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-18943087

RESUMEN

ABSTRACT A leaf spot disease with unknown etiology has become more pronounced in spring and winter barley in Germany in recent years. The symptoms are similar to net blotch and Ramularia leaf spots, but the causal agents of these diseases are not identified. The symptom expression varied much on cultivars. Cultivars most affected by the disease of both spring and winter barley showed a significantly higher level of superoxide (O(2) ) production and lipid peroxidation (malondialdehyde), but a lower level of antioxidant potential expressed as superoxide dismutase (SOD) activity, catalase activity, and integral water-soluble antioxidant capacity (ACW) than insensitive cultivars. A high positive correlation between O(2) production and leaf spot development between ear emergence and milk ripeness was established in the most sensitive winter barley cv. Anoa (r(2) = 0.9622) and spring barley cv. Barke (r(2) = 0.9434). Leaf H(2)O(2) levels increased with the severity of leaf spots. The histochemical localization of O(2) and H(2)O(2) in the tissues adjacent to leaf spots indicated that these two active oxygen species (AOS) are involved in the formation of leaf spots. Reduction of symptom severity by applying strobilurin and azole fungicides was always associated with elevated SOD activity and ACW content and suppressed O(2) production. However, peroxidase activities were significantly higher in sensitive cultivars and in more severely affected tissues and decreased by applying fungicides. Thus, it is assumed that a possible genetic mechanism based on the imbalanced AOS metabolism contributes to formation of physiological leaf spots.

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