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1.
Front Plant Sci ; 15: 1354413, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38766473

RESUMEN

Chickpea (Cicer arietinum L.) is a very important food legume and needs improved drought tolerance for higher seed production in dry environments. The aim of this study was to determine diversity and genetic polymorphism in zinc finger knuckle genes with CCHC domains and their functional analysis for practical improvement of chickpea breeding. Two CaZF-CCHC genes, Ca04468 and Ca07571, were identified as potentially important candidates associated with plant responses to drought and dehydration. To study these genes, various methods were used including Sanger sequencing, DArT (Diversity array technology) and molecular markers for plant genotyping, gene expression analysis using RT-qPCR, and associations with seed-related traits in chickpea plants grown in field trials. These genes were studied for genetic polymorphism among a set of chickpea accessions, and one SNP was selected for further study from four identified SNPs between the promoter regions of each of the two genes. Molecular markers were developed for the SNP and verified using the ASQ and CAPS methods. Genotyping of parents and selected breeding lines from two hybrid populations, and SNP positions on chromosomes with haplotype identification, were confirmed using DArT microarray analysis. Differential expression profiles were identified in the parents and the hybrid populations under gradual drought and rapid dehydration. The SNP-based genotypes were differentially associated with seed weight per plant but not with 100 seed weight. The two developed and verified SNP molecular markers for both genes, Ca04468 and Ca07571, respectively, could be used for marker-assisted selection in novel chickpea cultivars with improved tolerance to drought and dehydration.

3.
Front Plant Sci ; 14: 1221790, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37900763

RESUMEN

Early determination of transgenic plants that are homozygous for a single locus T-DNA insert is highly desirable in most fundamental and applied transgenic research. This study aimed to build on an accurate, rapid, and reliable quantitative real-time PCR (qPCR) method to fast-track the development of multiple homozygous transgenic rice lines in the T1 generation, with low copy number to single T-DNA insert for further analyses. Here, a well-established qPCR protocol, based on the OsSBE4 reference gene and the nos terminator, was optimized in the transgenic Japonica rice cultivar Nipponbare, to distinguish homozygous single-insert plants with 100% accuracy. This method was successfully adapted to transgenic Indica rice plants carrying three different T-DNAs, without any modifications to quickly develop homozygous rice plants in the T1 generation. The accuracy of this qPCR method when applied to transgenic Indica rice approached 100% in 12 putative transgenic lines. Moreover, this protocol also successfully detected homozygous single-locus T-DNA transgenic rice plants with two-transgene T-DNAs, a feature likely to become more popular in future transgenic research. The assay was developed utilizing universal primers targeting common sequence elements of gene cassettes (the nos terminator). This assay could therefore be applied to other transgenic plants carrying the nos terminator. All procedures described here use standardized qPCR reaction conditions and relatively inexpensive dyes, such as SYBR Green, thus the qPCR method could be cost-effective and suitable for lower budget laboratories that are involved in rice transgenic research.

4.
J Emerg Med ; 64(6): 714-717, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-37183055

RESUMEN

BACKGROUND: Biatrial thrombus is a rare condition that is typically associated with a patent foramen ovale (PFO). CASE REPORT: This is a case of a 75-year-old man with history of heavy alcohol use found down with altered sensorium. He was hypothermic and in atrial fibrillation with rapid ventricular rate and was subsequently found to have a biatrial thrombus with no evidence of PFO. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Biatrial thrombus presents the unique danger of progressing to both pulmonary embolus and acute embolic disease (including stroke); both are life-threatening diagnoses that can be prevented by means of identifying and treating this rare and dangerous condition.


Asunto(s)
Fibrilación Atrial , Foramen Oval Permeable , Embolia Pulmonar , Accidente Cerebrovascular , Trombosis , Masculino , Humanos , Anciano , Fibrilación Atrial/complicaciones , Trombosis/complicaciones , Embolia Pulmonar/complicaciones , Foramen Oval Permeable/complicaciones , Accidente Cerebrovascular/complicaciones
5.
Front Plant Sci ; 13: 876843, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36466234

RESUMEN

Stress-responsive components of the mitochondrial alternative electron transport pathway have the capacity to improve tolerance of plants to abiotic stress, particularly the alternative oxidase AOX1A but also external NAD(P)H dehydrogenases such as NDB2, in Arabidopsis. NDB2 and AOX1A can cooperate to entirely circumvent the classical electron transport chain in Arabidopsis mitochondria. Overexpression of AOX1A or NDB2 alone can have slightly negative impacts on plant growth under optimal conditions, while simultaneous overexpression of NDB2 and AOX1A can reverse these phenotypic effects. We have taken a global transcriptomic approach to better understand the molecular shifts that occur due to overexpression of AOX1A alone and with concomitant overexpression of NDB2. Of the transcripts that were significantly up- or down- regulated in the AOX1A overexpression line compared to wild type (410 and 408, respectively), the majority (372 and 337, respectively) reverted to wild type levels in the dual overexpression line. Several mechanisms for the AOX1A overexpression phenotype are proposed based on the functional classification of these 709 genes, which can be used to guide future experiments. Only 28 genes were uniquely up- or down-regulated when NDB2 was overexpressed in the AOX1A overexpression line. On the other hand, many unique genes were deregulated in the NDB2 knockout line. Furthermore, several changes in transcript abundance seen in the NDB2 knockout line were consistent with changes in the AOX1A overexpression line. The results suggest that an imbalance in AOX1A:NDB2 protein levels caused by under- or over-expression of either component, triggers a common set of transcriptional responses that may be important in mitochondrial redox regulation. The most significant changes were transcripts associated with photosynthesis, secondary metabolism and oxidative stress responses.

6.
Front Plant Sci ; 13: 948099, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36186054

RESUMEN

Height from soil at the base of plant to the first pod (HFP) is an important trait for mechanical harvesting of legume crops. To minimise the loss of pods, the HFP must be higher than that of the blades of most combine harvesters. Here, we review the genetic control, morphology, and variability of HFP in legumes and attempt to unravel the diverse terminology for this trait in the literature. HFP is directly related to node number and internode length but through different mechanisms. The phenotypic diversity and heritability of HFP and their correlations with plant height are very high among studied legumes. Only a few publications describe a QTL analysis where candidate genes for HFP with confirmed gene expression have been mapped. They include major QTLs with eight candidate genes for HFP, which are involved in auxin transport and signal transduction in soybean [Glycine max (L.) Merr.] as well as MADS box gene SOC1 in Medicago trancatula, and BEBT or WD40 genes located nearby in the mapped QTL in common bean (Phaseolus vulgaris L.). There is no information available about simple and efficient markers associated with HFP, which can be used for marker-assisted selection for this trait in practical breeding, which is still required in the nearest future. To our best knowledge, this is the first review to focus on this significant challenge in legume-based cropping systems.

7.
Int J Mol Sci ; 22(22)2021 Nov 10.
Artículo en Inglés | MEDLINE | ID: mdl-34830037

RESUMEN

Two genes, HvSAP8 and HvSAP16, encoding Zinc-finger proteins, were identified earlier as active in barley plants. Based on bioinformatics and sequencing analysis, six SNPs were found in the promoter regions of HvSAP8 and one in HvSAP16, among parents of two barley segregating populations, Granal × Baisheshek and Natali × Auksiniai-2. ASQ and Amplifluor markers were developed for HvSAP8 and HvSAP16, one SNP in each gene, and in each of two populations, showing simple Mendelian segregation. Plants of F6 selected breeding lines and parents were evaluated in a soil-based drought screen, revealing differential expression of HvSAP8 and HvSAP16 corresponding with the stress. After almost doubling expression during the early stages of stress, HvSAP8 returned to pre-stress level or was strongly down-regulated in plants with Granal or Baisheshek genotypes, respectively. For HvSAP16 under drought conditions, a high expression level was followed by either a return to original levels or strong down-regulation in plants with Natali or Auksiniai-2 genotypes, respectively. Grain yield in the same breeding lines and parents grown under moderate drought was strongly associated with their HvSAP8 and HvSAP16 genotypes. Additionally, Granal and Natali genotypes with specific alleles at HvSAP8 and HvSAP16 were associated with improved performance under drought via higher 1000 grain weight and more shoots per plant, respectively.


Asunto(s)
Alelos , Regulación de la Expresión Génica de las Plantas , Hordeum , Proteínas de Plantas , Polimorfismo de Nucleótido Simple , Estrés Fisiológico/genética , Factores de Transcripción , Deshidratación , Hordeum/genética , Hordeum/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Dedos de Zinc
8.
Prehosp Disaster Med ; 36(5): 543-546, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34425934

RESUMEN

INTRODUCTION: Along with an increase in opioid deaths, there has been a desire to increase the accessibility of naloxone. However, in the absence of respiratory depression, naloxone is unlikely to be beneficial and may be deleterious if it precipitates withdrawal in individuals with central nervous system (CNS) depression due to non-opioid etiologies. OBJECTIVE: The aim of this study was to evaluate how effective prehospital providers were in administering naloxone. METHODS: This is a retrospective study of naloxone administration in two large urban Emergency Medical Service (EMS) systems. The proportion of patients who had a respiratory rate of at least 12 breaths per minute at the time of naloxone administration by prehospital providers was determined. RESULTS: During the two-year study period, 2,580 patients who received naloxone by prehospital providers were identified. The median (interquartile range) respiratory rate prior to naloxone administration was 12 (6-16) breaths per minute. Using an a priori respiratory rate of under 12 breaths per minute to define respiratory depression, only 1,232 (47.8%; 95% CI, 50.3%-54.2%) subjects who received naloxone by prehospital providers had respiratory depression. CONCLUSION: This study showed that EMS providers in Los Angeles County, California (USA) frequently administered naloxone to individuals without respiratory depression.


Asunto(s)
Sobredosis de Droga , Servicios Médicos de Urgencia , Insuficiencia Respiratoria , Analgésicos Opioides/uso terapéutico , Sobredosis de Droga/tratamiento farmacológico , Humanos , Los Angeles , Naloxona/uso terapéutico , Antagonistas de Narcóticos/uso terapéutico , Insuficiencia Respiratoria/inducido químicamente , Insuficiencia Respiratoria/tratamiento farmacológico , Estudios Retrospectivos
9.
Am Surg ; : 31348211025748, 2021 Jun 09.
Artículo en Inglés | MEDLINE | ID: mdl-34105994

RESUMEN

Actinomycosis is an infection characterized by abscess formation, draining sinuses, and tissue fibrosis. The causative bacterium is a Gram-positive facultative anaerobe from the genus Actinomyces. Infections classically affect the cervicofacial, thoracic, or pelvic region and often require prolonged antibiotic therapy. Actinomycosis of the breast is a rare condition that may present as a recurrent breast abscess. We present a 33-year-old female with a recurrent breast abscess which grew A. radingae and A. israeli on aspirated fluid cultures. Treatment with surgical aspiration and a 6-week course of oral amoxicillin/clavulanic acid 875 mg twice daily resulted in clinical improvement. Our case demonstrates how recurrent breast abscesses caused by Actinomyces can be difficult to manage. Long-term antibiotic therapy with surgical aspiration and regular follow-up offer the best chance of clinical resolution.

10.
Front Plant Sci ; 12: 643024, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33747023

RESUMEN

Tartaric acid (TA) is an obscure end point to the catabolism of ascorbic acid (Asc). Here, it is proposed as a "specialized primary metabolite", originating from carbohydrate metabolism but with restricted distribution within the plant kingdom and lack of known function in primary metabolic pathways. Grapes fall into the list of high TA-accumulators, with biosynthesis occurring in both leaf and berry. Very little is known of the TA biosynthetic pathway enzymes in any plant species, although recently some progress has been made in this space. New technologies in grapevine research such as the development of global co-expression network analysis tools and genome-wide association studies, should enable more rapid progress. There is also a lack of information regarding roles for this organic acid in plant metabolism. Therefore this review aims to briefly summarize current knowledge about the key intermediates and enzymes of TA biosynthesis in grapes and the regulation of its precursor, ascorbate, followed by speculative discussion around the potential roles of TA based on current knowledge of Asc metabolism, TA biosynthetic enzymes and other aspects of fruit metabolism.

11.
Front Plant Sci ; 12: 747886, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-35082803

RESUMEN

The proposed method is a modified and improved version of the existing "Allele-specific q-PCR" (ASQ) method for genotyping of single nucleotide polymorphism (SNP) based on fluorescence resonance energy transfer (FRET). This method is similar to frequently used techniques like Amplifluor and Kompetitive allele specific PCR (KASP), as well as others employing common universal probes (UPs) for SNP analyses. In the proposed ASQ method, the fluorophores and quencher are located in separate complementary oligonucleotides. The ASQ method is based on the simultaneous presence in PCR of the following two components: an allele-specific mixture (allele-specific and common primers) and a template-independent detector mixture that contains two or more (up to four) universal probes (UP-1 to 4) and a single universal quencher oligonucleotide (Uni-Q). The SNP site is positioned preferably at a penultimate base in each allele-specific primer, which increases the reaction specificity and allele discrimination. The proposed ASQ method is advanced in providing a very clear and effective measurement of the fluorescence emitted, with very low signal background-noise, and simple procedures convenient for customized modifications and adjustments. Importantly, this ASQ method is estimated as two- to ten-fold cheaper than Amplifluor and KASP, and much cheaper than all those methods that rely on dual-labeled probes without universal components, like TaqMan and Molecular Beacons. Results for SNP genotyping in the barley genes HvSAP16 and HvSAP8, in which stress-associated proteins are controlled, are presented as proven and validated examples. This method is suitable for bi-allelic uniplex reactions but it can potentially be used for 3- or 4-allelic variants or different SNPs in a multiplex format in a range of applications including medical, forensic, or others involving SNP genotyping.

12.
Int J Mol Sci ; 21(21)2020 Nov 05.
Artículo en Inglés | MEDLINE | ID: mdl-33167455

RESUMEN

Down-regulator associated protein, DrAp1, acts as a negative cofactor (NC2α) in a transcription repressor complex together with another subunit, down-regulator Dr1 (NC2ß). In binding to promotors and regulating the initiation of transcription of various genes, DrAp1 plays a key role in plant transition to flowering and ultimately in seed production. TaDrAp1 and TaDrAp2 genes were identified, and their expression and genetic polymorphism were studied using bioinformatics, qPCR analyses, a 40K Single nucleotide polymorphism (SNP) microarray, and Amplifluor-like SNP genotyping in cultivars of bread wheat (Triticum aestivum L.) and breeding lines developed from a cross between spelt (T. spelta L.) and bread wheat. TaDrAp1 was highly expressed under non-stressed conditions, and at flowering, TaDrAp1 expression was negatively correlated with yield capacity. TaDrAp2 showed a consistently low level of mRNA production. Drought caused changes in the expression of both TaDrAp1 and TaDrAp2 genes in opposite directions, effectively increasing expression in lower yielding cultivars. The microarray 40K SNP assay and Amplifluor-like SNP marker, revealed clear scores and allele discriminations for TaDrAp1 and TaDrAp2 and TaRht-B1 genes. Alleles of two particular homeologs, TaDrAp1-B4 and TaDrAp2-B1, co-segregated with grain yield in nine selected breeding lines. This indicated an important regulatory role for both TaDrAp1 and TaDrAp2 genes in plant growth, ontogenesis, and drought tolerance in bread and spelt wheat.


Asunto(s)
Regulación de la Expresión Génica de las Plantas/genética , Fosfoproteínas/genética , Factores de Transcripción/genética , Triticum/genética , Alelos , Sequías , Genes de Plantas/genética , Fosfoproteínas/metabolismo , Fitomejoramiento/métodos , Desarrollo de la Planta/genética , Polimorfismo de Nucleótido Simple/genética , Proteínas Represoras/genética , Proteínas Represoras/metabolismo , Semillas , Estrés Fisiológico/genética , Factores de Transcripción/metabolismo , Triticum/metabolismo
13.
BMC Plant Biol ; 20(Suppl 1): 156, 2020 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-33050881

RESUMEN

BACKGROUND: A family of genes designated as the Zinc finger A20/AN1 Transcription factors encoding stress-associated proteins (SAP) are well described in Arabidopsis and rice, and include 14 AtSAP and 18 OsSAP genes that are associated with variable tolerances to multiple abiotic stresses. The SAP gene family displays a great diversity in its structure and across different plant species. The aim of this study was to identify all HvSAP genes in barley (Hordeum vulgare L.), to analyse the expression of selected genes in response to salinity in barley leaves and develop SNP marker for HvSAP12 to evaluate the association between genotypes of barley plants and their grain yield in field trials. RESULTS: In our study, 17 HvSAP genes were identified in barley, which were strongly homologous to rice genes. Five genes, HvSAP5, HvSAP6, HvSAP11, HvSAP12 and HvSAP15, were found to be highly expressed in leaves of barley plants in response to salt stress in hydroponics compared to controls, using both semi-quantitative RT-PCR and qPCR analyses. The Amplifluor-like SNP marker KATU-B30 was developed and used for HvSAP12 genotyping. A strong association (R2 = 0.85) was found between KATU-B30 and grain yield production per plant of 50 F3 breeding lines originating from the cross Granal × Baisheshek in field trials with drought and low to moderate salinity in Northern and Central Kazakhstan. CONCLUSIONS: A group of HvSAP genes, and HvSAP12 in particular, play an important role in the tolerance of barley plants to salinity and drought, and is associated with higher grain yield in field trials. Marker-assisted selection with SNP marker KATU-B30 can be applied in barley breeding to improve grain yield production under conditions of abiotic stress.


Asunto(s)
Hordeum/genética , Proteínas de Plantas/genética , Polimorfismo de Nucleótido Simple , Estrés Salino/genética , Dedos de Zinc/genética , Biología Computacional , Marcadores Genéticos , Kazajstán , Oryza/genética , Dominios Proteicos , Reacción en Cadena en Tiempo Real de la Polimerasa , Especificidad de la Especie , Factores de Transcripción/genética , Transcriptoma
14.
BMC Plant Biol ; 20(Suppl 1): 183, 2020 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-33050887

RESUMEN

BACKGROUND: Chickpea is an important legume and is moderately tolerant to salinity stress during the growing season. However, the level and mechanisms for salinity tolerance can vary among accessions and cultivars. A large family of CaRab-GTP genes, previously identified in chickpea, is homologous to intracellular vesicle trafficking superfamily genes that play essential roles in response to salinity stress in plants. RESULTS: To determine which of the gene family members are involved in the chickpea salt response, plants from six selected chickpea accessions (Genesis 836, Hattrick, ICC12726, Rupali, Slasher and Yubileiny) were exposed to salinity stress and expression profiles resolved for the major CaRab-GTP gene clades after 5, 9 and 15 days of salt exposure. Gene clade expression profiles (using degenerate primers targeting all members of each clade) were tested for their relationship to salinity tolerance measures, namely plant biomass and Na+ accumulation. Transcripts representing 11 out of the 13 CaRab clades could be detected by RT-PCR, but only six (CaRabA2, -B, -C, -D, -E and -H) could be quantified using qRT-PCR due to low expression levels or poor amplification efficiency of the degenerate primers for clades containing several gene members. Expression profiles of three gene clades, CaRabB, -D and -E, were very similar across all six chickpea accessions, showing a strongly coordinated network. Salt-induced enhancement of CaRabA2 expression at 15 days showed a very strong positive correlation (R2 = 0.905) with Na+ accumulation in leaves. However, salinity tolerance estimated as relative plant biomass production compared to controls, did not correlate with Na+ accumulation in leaves, nor with expression profiles of any of the investigated CaRab-GTP genes. CONCLUSION: A coordinated network of CaRab-GTP genes, which are likely involved in intracellular trafficking, are important for the salinity stress response of chickpea plants.


Asunto(s)
Cicer/genética , Cicer/metabolismo , Hojas de la Planta/metabolismo , Cloruro de Sodio/farmacología , Sodio/metabolismo , Proteínas de Unión al GTP rab/metabolismo , Vesículas Citoplasmáticas/metabolismo , Perfilación de la Expresión Génica , Genes de Plantas , Potasio/metabolismo , Tolerancia a la Sal/genética
15.
Int J Mol Sci ; 21(11)2020 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-32481694

RESUMEN

All plants contain an alternative electron transport pathway (AP) in their mitochondria, consisting of the alternative oxidase (AOX) and type 2 NAD(P)H dehydrogenase (ND) families, that are thought to play a role in controlling oxidative stress responses at the cellular level. These alternative electron transport components have been extensively studied in plants like Arabidopsis and stress inducible isoforms identified, but we know very little about them in the important crop plant chickpea. Here we identify AP components in chickpea (Cicer arietinum) and explore their response to stress at the transcript level. Based on sequence similarity with the functionally characterized proteins of Arabidopsis thaliana, five putative internal (matrix)-facing NAD(P)H dehydrogenases (CaNDA1-4 and CaNDC1) and four putative external (inter-membrane space)-facing NAD(P)H dehydrogenases (CaNDB1-4) were identified in chickpea. The corresponding activities were demonstrated for the first time in purified mitochondria of chickpea leaves and roots. Oxidation of matrix NADH generated from malate or glycine in the presence of the Complex I inhibitor rotenone was high compared to other plant species, as was oxidation of exogenous NAD(P)H. In leaf mitochondria, external NADH oxidation was stimulated by exogenous calcium and external NADPH oxidation was essentially calcium dependent. However, in roots these activities were low and largely calcium independent. A salinity experiment with six chickpea cultivars was used to identify salt-responsive alternative oxidase and NAD(P)H dehydrogenase gene transcripts in leaves from a three-point time series. An analysis of the Na:K ratio and Na content separated these cultivars into high and low Na accumulators. In the high Na accumulators, there was a significant up-regulation of CaAOX1, CaNDB2, CaNDB4, CaNDA3 and CaNDC1 in leaf tissue under long term stress, suggesting the formation of a stress-modified form of the mitochondrial electron transport chain (mETC) in leaves of these cultivars. In particular, stress-induced expression of the CaNDB2 gene showed a striking positive correlation with that of CaAOX1 across all genotypes and time points. The coordinated salinity-induced up-regulation of CaAOX1 and CaNDB2 suggests that the mitochondrial alternative pathway of respiration is an important facet of the stress response in chickpea, in high Na accumulators in particular, despite high capacities for both of these activities in leaf mitochondria of non-stressed chickpeas.


Asunto(s)
Cicer/genética , Cicer/fisiología , Mitocondrias/metabolismo , Proteínas Mitocondriales/genética , Oxidorreductasas/genética , Proteínas de Plantas/genética , Estrés Salino , Calcio/metabolismo , Transporte de Electrón , Regulación Enzimológica de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , NADPH Deshidrogenasa/metabolismo , Oxígeno/metabolismo , Fotosíntesis , Raíces de Plantas/metabolismo , Brotes de la Planta/metabolismo , Sodio/química , Especificidad de la Especie , Transcriptoma
17.
New Phytol ; 225(3): 1072-1090, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-31004496

RESUMEN

Agriculture is expanding into regions that are affected by salinity. This review considers the energetic costs of salinity tolerance in crop plants and provides a framework for a quantitative assessment of costs. Different sources of energy, and modifications of root system architecture that would maximize water vs ion uptake are addressed. Energy requirements for transport of salt (NaCl) to leaf vacuoles for osmotic adjustment could be small if there are no substantial leaks back across plasma membrane and tonoplast in root and leaf. The coupling ratio of the H+ -ATPase also is a critical component. One proposed leak, that of Na+ influx across the plasma membrane through certain aquaporin channels, might be coupled to water flow, thus conserving energy. For the tonoplast, control of two types of cation channels is required for energy efficiency. Transporters controlling the Na+ and Cl- concentrations in mitochondria and chloroplasts are largely unknown and could be a major energy cost. The complexity of the system will require a sophisticated modelling approach to identify critical transporters, apoplastic barriers and root structures. This modelling approach will inform experimentation and allow a quantitative assessment of the energy costs of NaCl tolerance to guide breeding and engineering of molecular components.


Asunto(s)
Productos Agrícolas/fisiología , Metabolismo Energético , Tolerancia a la Sal/fisiología , Transporte Biológico , Respiración de la Célula , Raíces de Plantas/anatomía & histología
18.
J Biol Chem ; 294(44): 15932-15946, 2019 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-31488549

RESUMEN

Tartaric acid has high economic value as an antioxidant and flavorant in food and wine industries. l-Tartaric acid biosynthesis in wine grape (Vitis vinifera) uses ascorbic acid (vitamin C) as precursor, representing an unusual metabolic fate for ascorbic acid degradation. Reduction of the ascorbate breakdown product 2-keto-l-gulonic acid to l-idonic acid constitutes a critical step in this l-tartaric acid biosynthetic pathway. However, the underlying enzymatic mechanisms remain obscure. Here, we identified a V. vinifera aldo-keto reductase, Vv2KGR, with 2-keto-l-gulonic acid reductase activity. Vv2KGR belongs to the d-isomer-specific 2-hydroxyacid dehydrogenase superfamily and displayed the highest similarity to the hydroxyl pyruvate reductase isoform 2 in Arabidopsis thaliana Enzymatic analyses revealed that Vv2KGR efficiently reduces 2-keto-l-gulonic acid to l-idonic acid and uses NADPH as preferred coenzyme. Moreover, Vv2KGR exhibited broad substrate specificity toward glyoxylate, pyruvate, and hydroxypyruvate, having the highest catalytic efficiency for glyoxylate. We further determined the X-ray crystal structure of Vv2KGR at 1.58 Å resolution. Comparison of the Vv2KGR structure with those of d-isomer-specific 2-hydroxyacid dehydrogenases from animals and microorganisms revealed several unique structural features of this plant hydroxyl pyruvate reductase. Substrate structural analysis indicated that Vv2KGR uses two modes (A and B) to bind different substrates. 2-Keto-l-gulonic acid displayed the lowest predicted free-energy binding to Vv2KGR among all docked substrates. Hence, we propose that Vv2KGR functions in l-tartaric acid biosynthesis. To the best of our knowledge, this is the first report of a d-isomer-specific 2-hydroxyacid dehydrogenase that reduces 2-keto-l-gulonic acid to l-idonic acid in plants.


Asunto(s)
Aldo-Ceto Reductasas/metabolismo , Ácido Ascórbico/metabolismo , Proteínas de Plantas/metabolismo , Azúcares Ácidos/metabolismo , Tartratos/metabolismo , Vitis/enzimología , Aldo-Ceto Reductasas/química , Dominio Catalítico , Glioxilatos/metabolismo , Proteínas de Plantas/química , Ácido Pirúvico/metabolismo , Especificidad por Sustrato , Vitis/metabolismo
19.
Plant Physiol ; 181(2): 774-788, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31409698

RESUMEN

In addition to the classical electron transport pathway coupled to ATP synthesis, plant mitochondria have an alternative pathway that involves type II NAD(P)H dehydrogenases (NDs) and alternative oxidase (AOX). This alternative pathway participates in thermogenesis in select organs of some species and is thought to help prevent cellular damage during exposure to environmental stress. Here, we investigated the function and role of one alternative path component, AtNDB2, using a transgenic approach in Arabidopsis (Arabidopsis thaliana). Disruption of AtNDB2 expression via T-DNA insertion led to a 90% decrease of external NADH oxidation in isolated mitochondria. Overexpression of AtNDB2 led to increased AtNDB2 protein abundance in mitochondria but did not enhance external NADH oxidation significantly unless AtAOX1A was concomitantly overexpressed and activated, demonstrating a functional link between these enzymes. Plants lacking either AtAOX1A or AtNDB2 were more sensitive to combined drought and elevated light treatments, whereas plants overexpressing these components showed increased tolerance and capacity for poststress recovery. We conclude that AtNDB2 is the predominant external NADH dehydrogenase in mitochondria and together with AtAOX1A forms a complete, functional, nonphosphorylating pathway of electron transport, whose operation enhances tolerance to environmental stress. This study demonstrates that at least one of the alternative NDs, as well as AOX, are important for the stress response.


Asunto(s)
Arabidopsis/enzimología , Mitocondrias/enzimología , Proteínas Mitocondriales/metabolismo , NADH Deshidrogenasa/metabolismo , Oxidorreductasas/metabolismo , Proteínas de Plantas/metabolismo , Estrés Fisiológico , Arabidopsis/genética , Arabidopsis/crecimiento & desarrollo , Respiración de la Célula , Proteínas Mitocondriales/genética , NADH Deshidrogenasa/genética , Oxidorreductasas/genética , Proteínas de Plantas/genética , Plantas Modificadas Genéticamente
20.
Clin Med (Lond) ; 19(3): 252-254, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-31092522

RESUMEN

With the incidence of syphilis more than doubling over the last decade, knowledge of its manifestations is of increasing importance. Yet, today's clinicians are less experienced in the recognition of syphilis than the physicians of Osler's day.In this case, a 56-year-old man presented with acute confusion and a history suggestive of encephalitis. Neuroimaging revealed cystic infarcts. He was subsequently tested for HIV and syphilis and found to be positive for both. HIV co-infection had accelerated the rate of neurosyphilis progression. After timely diagnosis and treatment of both conditions, cognitive testing returned to baseline.This case highlights that neuroimaging can often show non-specific infarcts and haemorrhages instead of characteristic syphilitic gummae. This variability adds to the challenge of diagnosis. Thus syphilis serology screening should be sent in those presenting with acute confusion and neuroimaging abnormalities. In cases of cryptogenic stroke, syphilis serology should be added to the screening tests.


Asunto(s)
Neurosífilis , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Isquemia Encefálica/complicaciones , Isquemia Encefálica/diagnóstico por imagen , Isquemia Encefálica/patología , Diagnóstico Diferencial , Infecciones por VIH/complicaciones , Infecciones por VIH/diagnóstico , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Neurosífilis/complicaciones , Neurosífilis/diagnóstico por imagen , Neurosífilis/patología , Accidente Cerebrovascular , Tomografía Computarizada por Rayos X
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