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1.
J Infect Chemother ; 2024 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-39214386

RESUMEN

BACKGROUND: The National Early Warning Score 2 (NEWS2) standardizes assessment and response to acute illnesses using vital signs. Whether NEWS2 is useful in predicting the prognosis of candidemia remains to be determined. METHODS: Our study, conducted as a rigorous and retrospective analysis, examined patients with candidemia who were hospitalized between January 2014 and December 2023. We assessed candidemia severity using the Pitt Bacteremia Score (PBS) and NEWS2, while the Charlson Comorbidity Index (CCI) was used to assess underlying medical conditions. The endpoint was all-cause mortality within 30 days of candidemia onset, ensuring comprehensive evaluation of the patient's prognosis. RESULTS: Overall, 93 patients with candidemia were included. The 30-day all-cause mortality rate was 29.0 %. The area under the receiver operating characteristic curve (AUC) for CCI, PBS, and NEWS2 were 0.87 (95 % confidence interval [CI]: 0.80-0.95), 0.75 (95 % CI: 0.66-0.85), and 0.92 (95 % CI: 0.87-0.97), respectively, for predicting the 30-day mortality in patients with candidemia. The AUC values for CCI combined with PBS and NEWS2 were 0.89 (95 % CI: 0.83-0.96) and 0.96 (95 % CI: 0.93-1.00) for predicting the 30-day mortality in candidemia. Among the items that were significant in the univariate analysis, multivariate analysis showed that the combination of NEWS2 ≥ 10 and CCI ≥4 was the helpful prognostic factor for 30-day mortality. CONCLUSIONS: The combination of NEWS2 ≥ 10 and CCI ≥4 scores may be useful in predicting the risk of 30-day mortality in patients with candidemia.

2.
Nanomaterials (Basel) ; 14(2)2024 Jan 12.
Artículo en Inglés | MEDLINE | ID: mdl-38251139

RESUMEN

This study investigates the nanostructural properties of pseudo-binary Al-1.0Mg2Si (mass%) alloys with and without 0.5Cu using transmission electron microscopy (TEM) and small-angle neutron scattering (SANS). The TEM results show that both alloys exhibit extra electron diffraction spots related to MgSiMg second clusters at peak-aged conditions. High-resolution TEM images have revealed that the second cluster exists as a needle-shaped precipitate that is shorter and thicker than the ß″ phase. We found that the second cluster, which we referred to as the R phase in this paper, is more likely to form partially along the longitudinal axis of a random-type precipitate. Thus, the atomic arrangement in the random-type precipitate is not completely random. SANS is used to quantify the size and volume fraction of the observed needle-shaped precipitates since the R phase is difficult to observe with TEM. The R phase forms even in the Cu-free alloy, but the volume fraction is low, and the growth and formation are retarded near the peak-aged conditions. Undoubtedly, the Cu addition has the effect of stabilizing the growth of the R phase and also promoting its formation. Therefore, the R phase also contributes to the increase in hardness at both under- and peak-aged conditions in the Cu-containing alloy in addition to the strengthening ß″ phases.

3.
Mol Biol Evol ; 40(9)2023 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-37595132

RESUMEN

Horizontal gene transfer (HGT) is a means of exchanging genetic material asexually. The process by which horizontally transferred genes are domesticated by the host genome is of great interest but is not well understood. In this study, we determined the telomere-to-telomere genome sequence of the wheat-infecting Pyricularia oryzae strain Br48. SNP analysis indicated that the Br48 strain is a hybrid of wheat- and Brachiaria-infecting strains by a sexual or parasexual cross. Comparative genomic analysis identified several megabase-scale "insertions" in the Br48 genome, some of which were possibly gained by HGT-related events from related species, such as P. pennisetigena or P. grisea. Notably, the mega-insertions often contained genes whose phylogeny is not congruent with the species phylogeny. Moreover, some of the genes have a close homolog even in distantly related organisms, such as basidiomycetes or prokaryotes, implying the involvement of multiple HGT events. Interestingly, the levels of the silent epigenetic marks H3K9me3 and H3K27me3 in a genomic region tended to be negatively correlated with the phylogenetic concordance of genes in the same region, suggesting that horizontally transferred DNA is preferentially targeted for epigenetic silencing. Indeed, the putative HGT-derived genes were activated when MoKmt6, the gene responsible for H3K27me3 modification, was deleted. Notably, these genes also tended to be up-regulated during infection, suggesting that they are now under host control and have contributed to establishing a fungal niche. In conclusion, this study suggests that epigenetic modifications have played an important role in the domestication of HGT-derived genes in the P. oryzae genome.


Asunto(s)
Ascomicetos , Código de Histonas , Histonas/genética , Filogenia , ADN , Ascomicetos/genética , Triticum
4.
Plant Cell Physiol ; 64(1): 94-106, 2023 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-36222360

RESUMEN

Rice is the model C3 crop for investigating the starch biosynthesis mechanism in endosperm because of its importance in grain production. However, little is known about starch biosynthesis in the vegetative organs of rice. In this study, we used novel rice mutants by inserting Tos17 into the starch synthase (SS) IIIb gene, which is mainly expressed in the leaf sheath (LS) and leaf blade (LB), and an ss1 mutant to clarify the differences in roles among SS isozymes during starch biosynthesis. Native polyacrylamide gel electrophoresis (PAGE)/activity staining for SS, using LS and LB of ss mutants, revealed that the lowest migrating SS activity bands on the gel were derived from SSIIIb activity and those of two ss3b mutants were not detected. The apparent amylose content of LS starch of ss3b mutants increased. Moreover, the chain-length distribution and size-exclusion chromatography analysis using ss mutants showed that SSIIIb and SSI synthesize the B2-B3 chain and A-B1 chain of amylopectin in the LS and LB respectively. Interestingly, we also found that starch contents were decreased in the LS and LB of ss3b mutants, although SSI deficiency did not affect the starch levels. All these results indicated that SSIIIb synthesizes the long chain of amylopectin in the LS and LB similar to SSIIIa in the endosperm, while SSI synthesizes the short chain in the vegetative organ as the same in the endosperm.


Asunto(s)
Oryza , Almidón Sintasa , Amilopectina , Oryza/genética , Almidón Sintasa/genética , Semillas/genética , Almidón , Amilosa
5.
Mol Plant Pathol ; 23(11): 1658-1670, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-35957505

RESUMEN

Pyricularia oryzae and Pyricularia grisea are pathogens that cause blast disease in various monocots. It has been reported that P. oryzae infects the leaves and roots of rice via different mechanisms. However, it is unclear to what extent the tissue types affect the host specificities of P. oryzae and P. grisea. Here, we evaluated the tissue-specific infection strategies of P. oryzae and P. grisea in various gramineous plants. Generally, mycelial plug inoculation caused root browning but the degree of browning did not simply follow the disease index on leaves. Interestingly, the Triticum and Digitaria pathotypes caused strong root growth inhibition in rice, wheat, and barley. Moreover, the Digitaria pathotype inhibited root branching only in rice. Culture filtrate reproduced these inhibitory effects on root, suggesting that some secreted molecules are responsible for the inhibitions. Observation of root sections revealed that most of the infection hyphae penetrated intercellular spaces and further extended into root cells, regardless of pathotype and host plant. The infection hyphae of Digitaria and Triticum pathotypes tended to localize in the outer layer of rice roots, but not in those of wheat and barley roots. The infection hyphae of the Oryza pathotype were distributed in both the intercellular and intracellular spaces of rice root cells. Pathogenesis-related genes and reactive oxygen species accumulation were induced after root inoculation with all combinations. These results suggest that resistance reactions were induced in the roots of gramineous plants against the infection with Pyricularia isolates but failed to prevent fungal invasion.


Asunto(s)
Magnaporthe , Oryza , Ascomicetos , Especificidad del Huésped , Magnaporthe/genética , Oryza/microbiología , Enfermedades de las Plantas/microbiología , Raíces de Plantas , Pyricularia grisea , Especies Reactivas de Oxígeno , Triticum
6.
PLoS Negl Trop Dis ; 15(2): e0009103, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33617533

RESUMEN

Severe fever with thrombocytopenia syndrome (SFTS) is a bunyavirus infection with high mortality. Favipiravir has shown effectiveness in preventing and treating SFTS virus (SFTSV) infection in animal models. A multicenter non-randomized, uncontrolled single arm trial was conducted to collect data on the safety and the effectiveness of favipiravir in treatment of SFTS patients. All participants received favipiravir orally (first-day loading dose of 1800 mg twice a day followed by 800 mg twice a day for 7-14 days in total). SFTSV RT-PCR and biochemistry tests were performed at designated time points. Outcomes were 28-day mortality, clinical improvement, viral load evolution, and adverse events (AEs). Twenty-six patients were enrolled, of whom 23 were analyzed. Four of these 23 patients died of multi-organ failure within one week (28-day mortality rate: 17.3%). Oral favipiravir was well tolerated in the surviving patients. AEs (abnormal hepatic function and insomnia) occurred in about 20% of the patients. Clinical symptoms improved in all patients who survived from a median of day 2 to day10. SFTSV RNA levels in the patients who died were significantly higher than those in the survivors (p = 0.0029). No viral genomes were detectable in the surviving patients a median of 8 days after favipiravir administration. The 28-day mortality rate in this study was lower than those of the previous studies in Japan. The high frequency of hepatic dysfunction as an AE was observed. However, it was unclear whether this was merely a side effect of favipiravir, because liver disorders are commonly seen in SFTS patients. The results of this trial support the effectiveness of favipiravir for patients with SFTS.


Asunto(s)
Amidas/efectos adversos , Amidas/uso terapéutico , Pirazinas/efectos adversos , Pirazinas/uso terapéutico , Síndrome de Trombocitopenia Febril Grave/tratamiento farmacológico , Adulto , Anciano , Anciano de 80 o más Años , Amidas/administración & dosificación , Amidas/sangre , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos , Femenino , Humanos , Japón , Hepatopatías , Masculino , Persona de Mediana Edad , Phlebovirus/aislamiento & purificación , Pirazinas/administración & dosificación , Pirazinas/sangre , ARN Viral/aislamiento & purificación , Síndrome de Trombocitopenia Febril Grave/mortalidad , Trastornos del Inicio y del Mantenimiento del Sueño/inducido químicamente , Resultado del Tratamiento , Carga Viral/efectos de los fármacos
7.
Microscopy (Oxf) ; 69(3): 141-155, 2020 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-32115659

RESUMEN

Transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) enable the visualization of three-dimensional (3D) microstructures ranging from atomic to micrometer scales using 3D reconstruction techniques based on computed tomography algorithms. This 3D microscopy method is called electron tomography (ET) and has been utilized in the fields of materials science and engineering for more than two decades. Although atomic resolution is one of the current topics in ET research, the development and deployment of intermediate-resolution (non-atomic-resolution) ET imaging methods have garnered considerable attention from researchers. This research trend is probably not irrelevant due to the fact that the spatial resolution and functionality of 3D imaging methods of scanning electron microscopy (SEM) and X-ray microscopy have come to overlap with those of ET. In other words, there may be multiple ways to carry out 3D visualization using different microscopy methods for nanometer-scale objects in materials. From the above standpoint, this review paper aims to (i) describe the current status and issues of intermediate-resolution ET with regard to enhancing the effectiveness of TEM/STEM imaging and (ii) discuss promising applications of state-of-the-art intermediate-resolution ET for materials research with a particular focus on diffraction contrast ET for crystalline microstructures (superlattice domains and dislocations) including a demonstration of in situ dislocation tomography.

8.
Diagn Microbiol Infect Dis ; 95(2): 125-130, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31182246

RESUMEN

Human granulocytic anaplasmosis (HGA) is caused by Anaplasma phagocytophilum. Indirect immunofluorescence assay (IFA) is generally used for HGA serodiagnosis. A. phagocytophilum immunodominant P44 major outer membrane proteins are encoded by p44/msp2 multigene family, responsible for IFA reactivity. However, because multiple P44-related proteins may involve immunoreactivity in IFA, the available diagnostic antigens remain obscure. In this study, we identified 12 B-cell epitopes on triple P44-related proteins using peptide array that reacted with 4 HGA patients' sera. Then, peptide spot immunoassay using 14 synthetic peptides derived from those 12 epitopes as antigens was applied for the detection of antibody to A. phagocytophilum from patients with fever of unknown origin. The sensitivities and diagnostic efficiencies of this immunoassay were higher than those of Western blot analysis using 3 recombinant proteins previously developed. Thus, the immunoassay using our epitope-derived antigens, which has higher diagnostic performances, may have significant benefit for HGA serodiagnosis.


Asunto(s)
Anaplasma phagocytophilum/inmunología , Anaplasmosis/diagnóstico , Antígenos Bacterianos/inmunología , Proteínas de la Membrana Bacteriana Externa/química , Epítopos de Linfocito B/inmunología , Inmunoensayo/métodos , Secuencia de Aminoácidos , Anaplasma phagocytophilum/aislamiento & purificación , Anaplasmosis/sangre , Anaplasmosis/microbiología , Anticuerpos Antibacterianos/sangre , Antígenos Bacterianos/química , Proteínas de la Membrana Bacteriana Externa/inmunología , Western Blotting , Epítopos de Linfocito B/química , Humanos , Sensibilidad y Especificidad , Pruebas Serológicas
9.
Virology ; 534: 25-35, 2019 08.
Artículo en Inglés | MEDLINE | ID: mdl-31170545

RESUMEN

Three ourmia-like viruses, designated Pyricularia oryzae ourmia-like virus (PoOLV) 1 to 3, were identified in a wheat-infecting isolate of P. oryzae. The sizes of the full-length PoOLV1-3 genomes were determined to be 2,528, 1,671, and 2,557 nt. Interestingly, we also found two abundant single-stranded RNAs sharing their 5' terminal 25 and 255 nt with PoOLV1 RNA and PoOLV3 RNA, respectively. The PoOLV1- and PoOLV3-associated RNAs (ARNA1 and ARNA3) were 639 and 514 nt in length, and possessed one and two small ORFs, respectively. In the field isolates of P. oryzae, PoOLVs and ARNAs were detectable at varying levels, and the levels of PoOLV1 and ARNA1 as well as those of PoOLV3 and ARNA3, were tightly correlated. In addition, gene silencing of PoOLV1 and PoOLV3 resulted in a reduction of ARNA1 and ARNA3, respectively. There results indicated that replication of ARNA1 and ARNA3 was associated with PoOLV1 and PoOLV3, respectively.


Asunto(s)
Ascomicetos/virología , Virus Fúngicos/aislamiento & purificación , Enfermedades de las Plantas/microbiología , ARN Viral/metabolismo , Virus Fúngicos/clasificación , Virus Fúngicos/genética , Genoma Viral , Sistemas de Lectura Abierta , Filogenia , ARN Viral/genética , Triticum/microbiología , Proteínas Virales/genética , Proteínas Virales/metabolismo
10.
Plant Cell Physiol ; 60(5): 961-972, 2019 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-30690625

RESUMEN

CO2-responsive CCT protein (CRCT) is suggested to be a positive regulator of starch biosynthesis in the leaf sheaths of rice, regulating the expression levels of starch biosynthesis-related genes. In this study, the effects of CRCT expression levels on the expression of starch biosynthesis-related enzymes and the quality of starch were studied. Using native-PAGE/activity staining and immunoblotting, we found that the protein levels of starch synthase I, branching enzyme I, branching enzyme IIa, isoamylase 1 and phosphorylase 1 were largely correlated with the CRCT expression levels in the leaf sheaths of CRCT transgenic lines. In contrast, the CRCT expression levels largely did not affect the expression levels and/or activities of starch biosynthesis-related enzymes in the leaf blades and endosperm tissues. The analysis of the chain-length distribution of starch in the leaf sheaths showed that short chains with a degree of polymerization from 5 to 14 were increased in the overexpression lines but decreased in the knockdown lines. The amylose content of starch in the leaf sheath was greatly increased in the overexpression lines. In contrast, the molecular weight of the amylopectin of starch in the leaf sheath of overexpression lines did not change compared with those of the non-transgenic rice. These results suggest that CRCT can control the quality and the quantity of starch in the leaf sheath by regulating the expression of particular starch biosynthesis-related enzymes.


Asunto(s)
Dióxido de Carbono/metabolismo , Oryza/metabolismo , Hojas de la Planta/metabolismo , Almidón/metabolismo , Enzima Ramificadora de 1,4-alfa-Glucano/metabolismo , Amilosa/metabolismo , Isoamilasa/metabolismo , Almidón Sintasa/metabolismo
12.
Nucleic Acids Res ; 46(5): 2495-2508, 2018 03 16.
Artículo en Inglés | MEDLINE | ID: mdl-29309640

RESUMEN

Small RNA (sRNA)-mediated gene silencing phenomena, exemplified by RNA interference (RNAi), require a unique class of proteins called Argonautes (AGOs). An AGO protein typically forms a protein-sRNA complex that contributes to gene silencing using the loaded sRNA as a specificity determinant. Here, we show that MoAGO2, one of the three AGO genes in the fungus Pyricularia oryzae (Magnaporthe oryzae) interferes with RNAi. Gene knockout (KO) studies revealed that MoAGO1 and MoAGO3 additively or redundantly played roles in hairpin RNA- and retrotransposon (MAGGY)-triggered RNAi while, surprisingly, the KO mutants of MoAGO2 (Δmoago2) showed elevated levels of gene silencing. Consistently, transcript levels of MAGGY and mycoviruses were drastically reduced in Δmoago2, supporting the idea that MoAGO2 impeded RNAi against the parasitic elements. Deep sequencing analysis revealed that repeat- and mycovirus-derived small interfering RNAs were mainly associated with MoAGO2 and MoAGO3, and their populations were very similar based on their size distribution patterns and positional base preference. Site-directed mutagenesis studies indicated that sRNA binding but not slicer activity of MoAGO2 was essential for the ability to diminish the efficacy of RNAi. Overall, these results suggest a possible interplay between distinct sRNA-mediated gene regulation pathways through a competition for sRNA.


Asunto(s)
Proteínas Argonautas/metabolismo , Proteínas Fúngicas/metabolismo , Interferencia de ARN , ARN Interferente Pequeño/metabolismo , Proteínas Argonautas/biosíntesis , Proteínas Argonautas/genética , Proteínas Argonautas/fisiología , Ascomicetos/genética , Ascomicetos/virología , Gránulos Citoplasmáticos/metabolismo , Proteínas Fúngicas/biosíntesis , Proteínas Fúngicas/genética , Proteínas Fúngicas/fisiología , Virus Fúngicos/genética , Eliminación de Gen , Genoma Fúngico , Retroelementos
13.
Mol Plant Pathol ; 19(4): 975-985, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-28722830

RESUMEN

After invasion into intercellular spaces of tomato plants, the soil-borne, plant-pathogenic Ralstonia solanacearum strain OE1-1 forms mushroom-shaped biofilms (mushroom-type biofilms, mBFs) on tomato cells, leading to its virulence. The strain OE1-1 produces aryl-furanone secondary metabolites, ralfuranones (A, B, J, K and L), dependent on the quorum sensing (QS) system, with methyl 3-hydroxymyristate (3-OH MAME) synthesized by PhcB as a QS signal. Ralfuranones are associated with the feedback loop of the QS system. A ralfuranone productivity-deficient mutant (ΔralA) exhibited significantly reduced growth in intercellular spaces compared with strain OE1-1, losing its virulence. To analyse the function of ralfuranones in mBF formation by OE1-1 cells, we observed cell aggregates of R. solanacearum strains statically incubated in tomato apoplast fluids on filters under a scanning electron microscope. The ΔralA strain formed significantly fewer microcolonies and mBFs than strain OE1-1. Supplementation of ralfuranones A, B, J and K, but not L, significantly enhanced the development of mBF formation by ΔralA. Furthermore, a phcB- and ralA-deleted mutant (ΔphcB/ralA) exhibited less formation of mBFs than OE1-1, although a QS-deficient, phcB-deleted mutant formed mBFs similar to OE1-1. Supplementation with 3-OH MAME significantly reduced the formation of mBFs by ΔphcB/ralA. The application of each ralfuranone significantly increased the formation of mBFs by ΔphcB/ralA supplied with 3-OH MAME. Together, our findings indicate that ralfuranones are implicated not only in the development of mBFs by strain OE1-1, but also in the suppression of QS-mediated negative regulation of mBF formation.


Asunto(s)
Biopelículas/crecimiento & desarrollo , Lactonas/metabolismo , Ralstonia solanacearum/crecimiento & desarrollo , Ralstonia solanacearum/metabolismo , Solanum lycopersicum/microbiología , Percepción de Quorum , Virulencia
14.
Fungal Biol ; 121(2): 127-136, 2017 02.
Artículo en Inglés | MEDLINE | ID: mdl-28089044

RESUMEN

The Sclerotium is one of the most persistent organs in filamentous fungi. Control of sclerotial formation is promising in the prevention of sclerotial disease. In this study, cytological analyses of sclerotial development were conducted in Sclerotinia minor. Number and size of sclerotia were correlated with nutrient concentration of the media. Interruption of aeration by sealing with parafilm completely suppressed sclerotial formation. We also found that reactive oxygen species (ROS) generated two phases, i.e., hydrogen peroxide at sclerotial initial (SI) stage and O2- at outer layer of sclerotial development/mature stages, during sclerotial formation. Ultrastructural analyses revealed that ROS was prominently produced at the outer layer of sclerotia in sclerotial mature (SM) phase. Although most of the inhibitors for ROS generation enzymes were ineffective for sclerotial formation, ascorbic acid, one of the scavengers of hydrogen peroxide, inhibited melanin biosynthesis during sclerotial maturation stage. The mycelia sealed with parafilm, when exogenously sprayed with hydrogen peroxide, could not produce sclerotium. These results indicated that ROS generation during sclerotial formation is mainly involved in the production of melanin layer.


Asunto(s)
Ascomicetos/citología , Ascomicetos/efectos de los fármacos , Hifa/crecimiento & desarrollo , Hifa/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Aerobiosis , Anaerobiosis , Ascomicetos/crecimiento & desarrollo , Ascomicetos/metabolismo , Medios de Cultivo/química , Melaninas/metabolismo
15.
Photosynth Res ; 131(1): 41-50, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-27432175

RESUMEN

Light and temperature affect state transitions through changes in the plastoquinone (PQ) redox state in photosynthetic organisms. We demonstrated that light and/or heat treatment induced preferential photosystem (PS) I excitation by binding light-harvesting complex II (LHCII) proteins. The photosystem of wheat was in state 1 after dark overnight treatment, wherein PQ was oxidized and most of LHCII was not bound to PSI. At the onset of the light treatment [25 °C in the light (100 µmol photons m-2 s-1)], two major LHCIIs, Lhcb1 and Lhcb2 were phosphorylated, and the PSI-LHCII supercomplex formed within 5 min, which coincided with an increase in the PQ oxidation rate. Heat treatment at 40 °C of light-adapted wheat led to further LHCII protein phosphorylation of, resultant cyclic electron flow promotion, which was accompanied by ultrafast excitation of PSI and structural changes of thylakoid membranes, thereby protecting PSII from heat damage. These results suggest that LHCIIs are required for the functionality of wheat plant PSI, as it keeps PQ oxidized by regulating photochemical electron flow, thereby helping acclimation to environmental changes.


Asunto(s)
Adaptación Fisiológica , Calor , Complejos de Proteína Captadores de Luz/química , Luz , Complejo de Proteína del Fotosistema I/química , Fosforilación , Espectrometría de Fluorescencia , Tilacoides/metabolismo
16.
Plant Cell Physiol ; 57(11): 2334-2341, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27519315

RESUMEN

CO2-responsive CCT protein (CRCT) is the suggested positive regulator of starch synthesis in vegetative organs, particularly the leaf sheath of rice. In this study, we analyzed the effects of the starch level in the leaf sheath on the photosynthetic rate in the leaf blade using CRCT overexpression and RNA interference (RNAi) knockdown transgenic rice grown under ambient (38 Pa) or elevated (100 Pa) CO2 conditions. In leaf sheath, the starch content was markedly changed in relation to CRCT expression levels under both CO2 conditions. In contrast, the soluble sugar and starch contents of the leaf blade were markedly increased in the knockdown line grown under elevated CO2 conditions. The overexpression or RNAi knockdown of CRCT did not cause large effects on the photosynthetic rate of the transgenic lines grown under ambient CO2 condition. However, the photosynthetic rate of the overexpression line was enhanced, while that of the knockdown line was substantially decreased under elevated CO2 conditions. These photosynthetic rates were weakly correlated with the nitrogen contents and negatively correlated with the total non-structural carbohydrate contents. Thus, the capacity for starch synthesis in leaf sheath, which is controlled by CRCT, can indirectly affect the carbohydrate content, and then the photosynthetic rate in the leaf blade of rice grown under elevated CO2 conditions.


Asunto(s)
Dióxido de Carbono/farmacología , Oryza/fisiología , Fotosíntesis , Hojas de la Planta/metabolismo , Proteínas de Plantas/metabolismo , Almidón/metabolismo , Biomasa , Metabolismo de los Hidratos de Carbono/efectos de los fármacos , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Células del Mesófilo/efectos de los fármacos , Células del Mesófilo/metabolismo , Células del Mesófilo/ultraestructura , Nitrógeno/metabolismo , Oryza/genética , Oryza/crecimiento & desarrollo , Fotosíntesis/efectos de los fármacos , Hojas de la Planta/efectos de los fármacos , Hojas de la Planta/genética , Proteínas de Plantas/genética , Plantas Modificadas Genéticamente , Solubilidad
17.
Plant Physiol ; 170(4): 2024-39, 2016 04.
Artículo en Inglés | MEDLINE | ID: mdl-26884484

RESUMEN

Lipid-derived reactive carbonyl species (RCS) possess electrophilic moieties and cause oxidative stress by reacting with cellular components. Arabidopsis (Arabidopsis thaliana) has a chloroplast-localized alkenal/one oxidoreductase (AtAOR) for the detoxification of lipid-derived RCS, especially α,ß-unsaturated carbonyls. In this study, we aimed to evaluate the physiological importance of AtAOR and analyzed AtAOR (aor) mutants, including a transfer DNA knockout, aor (T-DNA), and RNA interference knockdown, aor (RNAi), lines. We found that both aor mutants showed smaller plant sizes than wild-type plants when they were grown under day/night cycle conditions. To elucidate the cause of the aor mutant phenotype, we analyzed the photosynthetic rate and the respiration rate by gas-exchange analysis. Subsequently, we found that both wild-type and aor (RNAi) plants showed similar CO2 assimilation rates; however, the respiration rate was lower in aor (RNAi) than in wild-type plants. Furthermore, we revealed that phosphoenolpyruvate carboxylase activity decreased and starch degradation during the night was suppressed in aor (RNAi). In contrast, the phenotype of aor (RNAi) was rescued when aor (RNAi) plants were grown under constant light conditions. These results indicate that the smaller plant sizes observed in aor mutants grown under day/night cycle conditions were attributable to the decrease in carbon utilization during the night. Here, we propose that the detoxification of lipid-derived RCS by AtAOR in chloroplasts contributes to the protection of dark respiration and supports plant growth during the night.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimología , Carbono/metabolismo , Cloroplastos/enzimología , Oscuridad , Oxidorreductasas Actuantes sobre Donantes de Grupos Aldehído u Oxo/metabolismo , Oxidorreductasas/metabolismo , Hojas de la Planta/enzimología , Supresión Genética , Acroleína/metabolismo , Arabidopsis/genética , Arabidopsis/efectos de la radiación , Proteínas de Arabidopsis/genética , Respiración de la Célula/efectos de la radiación , Clorofila/metabolismo , Cloroplastos/efectos de la radiación , ADN Bacteriano/genética , Regulación de la Expresión Génica de las Plantas/efectos de la radiación , Luz , Mutación/genética , Nitrógeno/metabolismo , Oxidorreductasas Actuantes sobre Donantes de Grupos Aldehído u Oxo/genética , Fenotipo , Fotosíntesis , Extractos Vegetales/metabolismo , Hojas de la Planta/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa , Almidón/metabolismo
18.
Micron ; 82: 1-8, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26748212

RESUMEN

Variations of Vickers hardness were observed in Al-Mg-Mn alloy and Al-Mg-Mn-Sc-Zr alloy at different ageing times, ranging from a peak value of 81.2 HV at 54 ks down to 67.4 HV at 360 ks, below the initial hardness value, 71.8 HV at 0 ks for the case of Al-Mg-Mn-Sc-Zr alloy. Microstructures of samples at each ageing stage were examined carefully by transmission electron microscopes (TEMs) both in two-dimensions and three-dimensions. The presence of different types, densities, and sizes of particles were observed dispersed spherical Al3Sc1-xZrx and also block-shaped Al3Sc precipitates growing along <100>Al with facets {100} and {110} of the precipitates. TEM analysis both in two-dimensions and three-dimensions, performed on various samples, confirmed the direct correlation between the hardness and the density of Al3Sc.

19.
Mol Plant Pathol ; 17(6): 890-902, 2016 08.
Artículo en Inglés | MEDLINE | ID: mdl-26609568

RESUMEN

The mechanism of colonization of intercellular spaces by the soil-borne and vascular plant-pathogenic bacterium Ralstonia solanacearum strain OE1-1 after invasion into host plants remains unclear. To analyse the behaviour of OE1-1 cells in intercellular spaces, tomato leaves with the lower epidermis layers excised after infiltration with OE1-1 were observed under a scanning electron microscope. OE1-1 cells formed microcolonies on the surfaces of tomato cells adjacent to intercellular spaces, and then aggregated surrounded by an extracellular matrix, forming mature biofilm structures. Furthermore, OE1-1 cells produced mushroom-type biofilms when incubated in fluids of apoplasts including intercellular spaces, but not xylem fluids from tomato plants. This is the first report of biofilm formation by R. solanacearum on host plant cells after invasion into intercellular spaces and mushroom-type biofilms produced by R. solanacearum in vitro. Sugar application led to enhanced biofilm formation by OE1-1. Mutation of lecM encoding a lectin, RS-IIL, which reportedly exhibits affinity for these sugars, led to a significant decrease in biofilm formation. Colonization in intercellular spaces was significantly decreased in the lecM mutant, leading to a loss of virulence on tomato plants. Complementation of the lecM mutant with native lecM resulted in the recovery of mushroom-type biofilms and virulence on tomato plants. Together, our findings indicate that OE1-1 produces mature biofilms on the surfaces of tomato cells after invasion into intercellular spaces. RS-IIL may contribute to biofilm formation by OE1-1, which is required for OE1-1 virulence.


Asunto(s)
Biopelículas , Espacio Extracelular/microbiología , Haz Vascular de Plantas/microbiología , Ralstonia solanacearum/patogenicidad , Solanum lycopersicum/microbiología , Adhesión Bacteriana/efectos de los fármacos , Biopolímeros/metabolismo , Carbohidratos/farmacología , Recuento de Colonia Microbiana , Espacio Extracelular/efectos de los fármacos , Solanum lycopersicum/efectos de los fármacos , Solanum lycopersicum/ultraestructura , Mutación/genética , Haz Vascular de Plantas/efectos de los fármacos , Ralstonia solanacearum/efectos de los fármacos , Ralstonia solanacearum/ultraestructura , Virulencia/efectos de los fármacos
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