RESUMO
AIMS/INTRODUCTION: This study aimed to investigate the diagnostic potential of two simplified tests, a point-of-care nerve conduction device (DPNCheck™) and a coefficient of variation of R-R intervals (CVR-R), as an alternative to traditional nerve conduction studies for the diagnosis of diabetic polyneuropathy (DPN) in patients with diabetes. MATERIALS AND METHODS: Inpatients with type 1 or type 2 diabetes (n = 167) were enrolled. The study population consisted of 101 men, with a mean age of 60.8 ± 14.8 years. DPN severity was assessed using traditional nerve conduction studies, and differentiated based on Baba's classification (BC). To examine the explanatory potential of variables in DPNCheck™ and CVR-R regarding the severity of DPN according to BC, a multiple regression analysis was carried out, followed by a receiver operating characteristic analysis. RESULTS: Based on BC, 61 participants (36.5% of the total) were categorized as having DPN severity of stage 2 or more. The multiple regression analysis yielded a predictive formula with high predictive power for DPN diagnosis (estimated severity of DPN in BC = 2.258 - 0.026 × nerve conduction velocity [m/s] - 0.594 × ln[sensory nerve action potential amplitude (µV)] + 0.528In[age(years)] - 0.178 × ln[CVR-R], r = 0.657). The area under the curve in receiver operating characteristic analysis was 0.880. Using the optimal cutoff value for DPN with severer than stage 2, the predictive formula showed good diagnostic efficacy: sensitivity of 83.6%, specificity of 79.2%, positive predictive value of 51.7% and negative predictive value of 76.1%. CONCLUSIONS: These findings suggest that DPN diagnosis using DPNCheck™ and CVR-R could improve diagnostic efficiency and accessibility for DPN assessment in patients with diabetes.
Assuntos
Neuropatias Diabéticas , Eletrocardiografia , Condução Nervosa , Sistemas Automatizados de Assistência Junto ao Leito , Humanos , Neuropatias Diabéticas/diagnóstico , Masculino , Pessoa de Meia-Idade , Condução Nervosa/fisiologia , Eletrocardiografia/instrumentação , Eletrocardiografia/métodos , Idoso , Feminino , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/diagnósticoRESUMO
We observed trees of the Japanese apricot, Prunus mume 'Nanko' (Rosaceae), bearing two types of flowers: 34% had blue fluorescent pollen under UV irradiation, and 66% had non-fluorescent pollen. The fluorescent pollen grains were abnormally crushed, sterile, and devoid of intine and pollenkitt. The development of microspores within anthers was investigated: in the abnormally developed anthers, tapetal cells were vacuolated at the unicellular microspore stage, and fluorescent pollen was produced. Compounds responsible for the blue fluorescence of pollen were identified as chlorogenic acid and 1-O-feruloyl-ß-D-glucose. The anthers with fluorescent pollen contained 6.7-fold higher and 3.8-fold lower amounts of chlorogenic acid and N 1,N 5,N 10-tri-p-coumaroylspermidine, respectively, compared to those with non-fluorescent pollen. The tapetal vacuolization, highly accumulated chlorogenic acid, and deficiency of N 1,N 5,N 10-tri-p-coumaroylspermidine imply that low-temperature stress during the early unicellular microspore stage caused a failure in microsporogenesis. Furthermore, potential effects of the visual difference on the bee behavior were also discussed through the colorimetry. The sterility, likely induced by low-temperature stress, and the preference of honeybees for fluorescence may reduce the pollination efficiency of P. mume.
RESUMO
BACKGROUND: A new physical control method using ultraviolet-B (UV-B) lamps and light-reflecting sheets (UV method) significantly suppressed a spider mite population on greenhouse strawberries. Although UV-B radiation may adversely affect the survival of phytoseiid mites, previous research has suggested that Neoseiulus californicus can improve its survival on exposure to UV-B irradiation by consuming antioxidants contained in tea and peach pollen. In this study, we evaluated strawberry pollen as an alternative food source for N. californicus and examined whether antioxidants in the pollen mitigated UV-B damage to N. californicus. RESULTS: The fecundity of N. californicus females reared on Tetranychus urticae decreased on shifting their diet to pollen. By contrast, females reared continuously on strawberry pollen produced as many eggs as females reared continuously on T. urticae. Survival and fecundity after UV-B irradiation were higher in females on the pollen diet. Oxygen radical absorbance capacity analysis revealed that the high antioxidant activity of strawberry pollen was due to four hydroxycinnamoyl spermidine derivatives. CONCLUSION: Strawberry pollen was an adequate alternative food source for N. californicus. Feeding on strawberry pollen, which contains spermidine derivatives with high antioxidant activity, mitigated UV-B damage. This shows the potential of combining the UV-method with N. californicus for controlling T. urticae in strawberries.
Assuntos
Fragaria , Ácaros , Tetranychidae , Animais , Feminino , Controle Biológico de Vetores , Pólen , Comportamento PredatórioRESUMO
AIMS/INTRODUCTION: A gold standard in the diagnosis of diabetic polyneuropathy (DPN) is a nerve conduction study. However, as a nerve conduction study requires expensive equipment and well-trained technicians, it is largely avoided when diagnosing DPN in clinical settings. Here, we validated a novel diagnostic method for DPN using a point-of-care nerve conduction device as an alternative way of diagnosis using a standard electromyography system. MATERIALS AND METHODS: We used a multiple regression analysis to examine associations of nerve conduction parameters obtained from the device, DPNCheck™, with the severity of DPN categorized by the Baba classification among 375 participants with type 2 diabetes. A nerve conduction study using a conventional electromyography system was implemented to differentiate the severity in the Baba classification. The diagnostic properties of the device were evaluated using a receiver operating characteristic curve. RESULTS: A multiple regression model to predict the severity of DPN was generated using sural nerve conduction data obtained from the device as follows: the severity of DPN = 2.046 + 0.509 × ln(age [years]) - 0.033 × (nerve conduction velocity [m/s]) - 0.622 × ln(amplitude of sensory nerve action potential [µV]), r = 0.649. Using a cut-off value of 1.3065 in the model, moderate-to-severe DPN was effectively diagnosed (area under the receiver operating characteristic curve 0.871, sensitivity 70.1%, specificity 87.7%, positive predictive value 83.0%, negative predictive value 77.3%, positive likelihood ratio 5.67, negative likelihood ratio 0.34). CONCLUSIONS: Nerve conduction parameters in the sural nerve acquired by the handheld device successfully predict the severity of DPN.
Assuntos
Neuropatias Diabéticas/diagnóstico , Condução Nervosa , Testes Imediatos , Adulto , Idoso , Idoso de 80 Anos ou mais , Eletromiografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Estatísticos , Índice de Gravidade de DoençaRESUMO
AIMS/INTRODUCTION: Diabetic polyneuropathy (DPN) develops in the early stage of diabetes. However, no common diagnostic protocol has yet been established. Here, to verify that the flicker electroretinogram using a hand-held device can detect the early dysfunction of the peripheral nervous system in patients with diabetes, we investigated the correlation between the progression of DPN and neuroretinal dysfunction. MATERIALS AND METHODS: In total, 184 participants with type 1 or 2 diabetes underwent a flicker electroretinogram (ERG) using a hand-held device RETeval™ and nerve conduction study. Participants were also evaluated for intima-media thickness, ankle-brachial index, toe brachial index and brachial-ankle pulse wave velocity. Parameters of the nerve conduction study were used to diagnose the severity according to Baba's classification. A multiple regression analysis was used to examine the associations of ERG parameters with the severity of DPN categorized by Baba's classification. Diagnostic properties of the device in DPN were evaluated using a receiver operating characteristic curve. RESULTS: A multiple regression model to predict the severity of DPN was generated using ERG. In the model, moderate-to-severe DPN was effectively diagnosed (area under the receiver operating characteristic curve 0.692, sensitivity 56.5%, specificity 78.3%, positive predictive value 70.6%, negative predictive value 66.1%, positive likelihood ratio 2.60, negative likelihood ratio 0.56). In the patients without diabetic retinopathy, the implicit time and amplitude in ERG significantly correlated with the parameters of the nerve conduction study, brachial-ankle pulse wave velocity and intima-media thickness. CONCLUSIONS: Electroretinogram parameters obtained by the hand-held device successfully predict the severity of DPN. The device might be useful to evaluate DPN.
Assuntos
Aterosclerose/fisiopatologia , Diabetes Mellitus Tipo 1/fisiopatologia , Diabetes Mellitus Tipo 2/fisiopatologia , Neuropatias Diabéticas/diagnóstico , Retinopatia Diabética/diagnóstico , Eletrorretinografia/instrumentação , Idoso , Índice Tornozelo-Braço , Aterosclerose/complicações , Espessura Intima-Media Carotídea , Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 2/complicações , Neuropatias Diabéticas/etiologia , Retinopatia Diabética/etiologia , Eletrorretinografia/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Condução Nervosa/fisiologia , Nervos Periféricos/fisiopatologia , Valor Preditivo dos Testes , Análise de Onda de Pulso , Curva ROC , Índice de Gravidade de DoençaRESUMO
Flowering plants attract pollinators via various stimuli such as odor, color, and shape. Factors determining the foraging behavior of pollinators remain a major theme in ecological and evolutionary research, although the floral traits and cognitive ability of pollinators have been investigated for centuries. Here we show that the autofluorescence emitted from pollen and anthers under UV irradiation may act as another attractant for flower-visiting insects. We have identified fluorescent compounds from pollen and anthers of five plant species as hydroxycinnamoyl derivatives. The fluorescent compounds are also shown to quench UV energy and exhibit antioxidant activity, indicating a function as protectants of pollen genes from UV-induced damage. A two-choice assay using honeybees in the field demonstrated that they perceived the blue fluorescence emitted from the fluorescent compounds and were attracted to it. This result suggested that the fluorescence from pollen and anthers serves as a visual cue to attract pollinators under sunlight.
Assuntos
Abelhas/fisiologia , Corantes Fluorescentes/química , Magnoliopsida/metabolismo , Pólen/química , Animais , Antioxidantes/química , Comportamento Animal/efeitos dos fármacos , Ácido Clorogênico/química , Ácido Clorogênico/farmacologia , Cromatografia Líquida de Alta Pressão , Flores/química , Flores/metabolismo , Magnoliopsida/química , Magnoliopsida/crescimento & desenvolvimento , Espectrometria de Massas , Microscopia Confocal , Pólen/metabolismo , Polinização , Espectrofotometria Ultravioleta , Raios UltravioletaRESUMO
Tricholoma matsutake, a basidiomycete, forms ectomycorrhizas with Pinus densiflora as the host tree. Its fruiting body, "matsutake" in Japanese, is an edible and highly prized mushroom, and it grows in a circle called a fairy ring. Beneath the fairy ring of T. matsutake, a whitish mycelium-soil aggregated zone, called "shiro" in Japanese, develops. The front of the shiro, an active mycorrhizal zone, functions to gather nutrients from the soil and roots to nourish the fairy ring. Bacteria and sporulating fungi decrease from the shiro front, whereas they increase inside and outside the shiro front. Ohara demonstrated that the shiro front exhibited antimicrobial activity, but the antimicrobial substance has remained unidentified for 50 years. We have identified the antimicrobial substance as the (oxalato)aluminate complex, known as a reaction product of oxalic acid and aluminum phosphate to release soluble phosphorus. The complex protects the shiro from micro-organisms, and contributes to its development.
Assuntos
Alumínio/química , Compostos Organometálicos/química , Compostos Organometálicos/farmacologia , Oxalatos/química , Microbiologia do Solo , Tricholoma/efeitos dos fármacos , Anti-Infecciosos/química , Anti-Infecciosos/isolamento & purificação , Anti-Infecciosos/farmacologia , Bactérias/efeitos dos fármacos , Fungos/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Compostos Organometálicos/isolamento & purificaçãoRESUMO
The metabolites of tebufenozide, a model compound, formed by the yeast-expressed human CYP3A4 and CYP2C19 were identified to clarify the substrate recognition mechanism of the human cytochrome P450 (CYP) isozymes. We then determined whether tebufenozide metabolites may be predicted in silico. Hydrogen abstraction energies were calculated with the density functional theory method B3LYP/6-31G(∗). A docking simulation was performed using FRED software. Several alkyl sites of tebufenozide were hydroxylated by CYP3A4 whereas only one site was modified by CYP2C19. The accessibility of each site of tebufenozide to the reaction center of CYP enzymes and the susceptibility of each hydrogen atom for metabolism by CYP enzymes were evaluated by a docking simulation and hydrogen abstraction energy estimation, respectively.
Assuntos
Simulação por Computador , Citocromo P-450 CYP2C19/metabolismo , Citocromo P-450 CYP3A/metabolismo , Hidrazinas/análise , Hidrazinas/metabolismo , Humanos , Simulação de Acoplamento Molecular , SoftwareRESUMO
We propose an approach of estimating individual growth curves based on the birthday information of Japanese Thoroughbred horses, with considerations of the seasonal compensatory growth that is a typical characteristic of seasonal breeding animals. The compensatory growth patterns appear during only the winter and spring seasons in the life of growing horses, and the meeting point between winter and spring depends on the birthday of each horse. We previously developed new growth curve equations for Japanese Thoroughbreds adjusting for compensatory growth. Based on the equations, a parameter denoting the birthday information was added for the modeling of the individual growth curves for each horse by shifting the meeting points in the compensatory growth periods. A total of 5,594 and 5,680 body weight and age measurements of Thoroughbred colts and fillies, respectively, and 3,770 withers height and age measurements of both sexes were used in the analyses. The results of predicted error difference and Akaike Information Criterion showed that the individual growth curves using birthday information better fit to the body weight and withers height data than not using them. The individual growth curve for each horse would be a useful tool for the feeding managements of young Japanese Thoroughbreds in compensatory growth periods.
RESUMO
The effects of blue and red light irradiation at night on abscisic acid (ABA) metabolism and anthocyanin synthesis were examined in grape berries. The expressions of VlMYBA1-2, VlMYBA2, UDP-glucose-flavonoid 3-O-glucosyltransferase (VvUFGT), 9-cis-epoxycarotenoid dioxygenase (VvNCED1), and ABA 8'-hydroxylase (VvCYP707A1) were also investigated. Endogenous ABA, its metabolite phaseic acid (PA), and the expressions of VvNCED1 and VvCYP707A1 were highest in red light-emitting diode (LED)-treated skin. In contrast, anthocyanin concentrations were highest in blue LED-treated skin, followed by red LED treatment. However, the expressions of VlMYBA1-2, VlMYBA2, and VvUFGT did not necessarily coincide with anthocyanin concentrations. The quality of coloring may depend on the amount of malvidin-based anthocyanin, which increased toward harvest in blue and red LED-treated skin, unlike in untreated controls. An increase in sugars was also observed in blue and red LED-treated skin. These results suggest that blue LED irradiation at night may be effective in increasing anthocyanin and sugar concentrations in grape berries. However, there is evidence that another factor may influence anthocyanin concentrations in grape berry skin significantly more than endogenous ABA: ABA concentrations were highest in red LED-treated skin, which had lower anthocyanin concentrations than blue LED-treated skin.
Assuntos
Ácido Abscísico/metabolismo , Antocianinas/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Luz , Reguladores de Crescimento de Plantas/metabolismo , Vitis/metabolismo , Ácido Abscísico/análise , Antocianinas/análise , Carboidratos/análise , Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/metabolismo , Dioxigenases/genética , Dioxigenases/metabolismo , Frutas/genética , Frutas/metabolismo , Frutas/efeitos da radiação , Perfilação da Expressão Gênica , Glucosiltransferases/genética , Glucosiltransferases/metabolismo , Reguladores de Crescimento de Plantas/análise , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Vitis/genética , Vitis/efeitos da radiaçãoRESUMO
The plant stress hormone abscisic acid (ABA) is critical for several abiotic stress responses. ABA signaling is normally repressed by group-A protein phosphatases 2C (PP2Cs), but stress-induced ABA binds Arabidopsis PYR/PYL/RCAR (PYL) receptors, which then bind and inhibit PP2Cs. X-ray structures of several receptor-ABA complexes revealed a tunnel above ABA's 3' ring CH that opens at the PP2C binding interface. Here, ABA analogs with sufficiently long 3' alkyl chains were predicted to traverse this tunnel and block PYL-PP2C interactions. To test this, a series of 3'-alkylsulfanyl ABAs were synthesized with different alkyl chain lengths. Physiological, biochemical and structural analyses revealed that a six-carbon alkyl substitution produced a potent ABA antagonist that was sufficiently active to block multiple stress-induced ABA responses in vivo. This study provides a new approach for the design of ABA analogs, and the results validated structure-based design for this target class.
Assuntos
Ácido Abscísico/análogos & derivados , Proteínas de Arabidopsis/antagonistas & inibidores , Fosfoproteínas Fosfatases/antagonistas & inibidores , Reguladores de Crescimento de Plantas , Ácido Abscísico/síntese química , Ácido Abscísico/farmacologia , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Germinação/efeitos dos fármacos , Lactuca/efeitos dos fármacos , Lactuca/metabolismo , Modelos Moleculares , Fosfoproteínas Fosfatases/metabolismo , Reguladores de Crescimento de Plantas/síntese química , Reguladores de Crescimento de Plantas/farmacologia , Fenômenos Fisiológicos Vegetais , Ligação Proteica , Raphanus/efeitos dos fármacos , Raphanus/metabolismo , Sementes/efeitos dos fármacos , Sementes/metabolismo , Relação Estrutura-AtividadeRESUMO
Percentile growth curves are often used as a clinical indicator to evaluate variations of children's growth status. In this study, we propose empirical percentile growth curves using Z-scores adapted for Japanese Thoroughbred horses, with considerations of the seasonal compensatory growth that is a typical characteristic of seasonal breeding animals. We previously developed new growth curve equations for Japanese Thoroughbreds adjusting for compensatory growth. Individual horses and residual effects were included as random effects in the growth curve equation model and their variance components were estimated. Based on the Z-scores of the estimated variance components, empirical percentile growth curves were constructed. A total of 5,594 and 5,680 body weight and age measurements of male and female Thoroughbreds, respectively, and 3,770 withers height and age measurements were used in the analyses. The developed empirical percentile growth curves using Z-scores are computationally feasible and useful for monitoring individual growth parameters of body weight and withers height of young Thoroughbred horses, especially during compensatory growth periods.
RESUMO
Abscisic acid (ABA, 1), a plant hormone, has electrophilicity derived almost entirely from the side-chain, 3-methylpenta-2,4-dienoic acid. The electrochemical property of ABA was investigated by analysis of its cathodic reaction. ABA methyl ester (1-Me) was reduced at a peak potential of -1.6 V to give a unique and unstable bicyclic compound (5-Me) as a major product at pH 3 and 7. This finding showed that an electron was absorbed in the conjugated dienecarboxyl group, and that C-5 with a high electron density attacked C-2' through an intramolecular nucleophilic addition. At pH 10, in addition to 5-Me, a compound 4-Me was formed by isomerization of 5-Me under alkaline conditions. For a cathodic reaction of ABA at pH 3 and 7, compound 5 was a major product as well as in the case of ABA methyl ester. However, at pH 10, a dimer (6) with an epoxy group, 1'-deoxy-ABA (7) and other compounds were formed instead of compounds 4 and 5. Compounds 4 and 5 were biologically inactive, suggesting the importance of the electrophilic side-chain of ABA for biological activity.
Assuntos
Ácido Abscísico/química , Eletrólise , Ácido Abscísico/metabolismo , Ácido Abscísico/farmacologia , Ésteres , Germinação/efeitos dos fármacos , Lactuca/efeitos dos fármacos , Lactuca/crescimento & desenvolvimento , Oxirredução , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Sementes/efeitos dos fármacos , Sementes/crescimento & desenvolvimentoRESUMO
We developed abscinazole-E2B (Abz-E2B), a practical and specific inhibitor of abscisic acid (ABA) 8'-hydroxylase (CYP707A), by structural modification of abscinazole-E1 (Abz-E1), another compound we developed. A butoxy group was introduced to Abz-E2B instead of the tosylate group of Abz-E1, in expectation of better water solubility, because the calculated logP value of Abz-E2B is 3.47, which is smaller than that of Abz-E1 (4.02). The water solubility of Abz-E2B was greater than 90% at a concentration of 100 µM, at which the solubility of Abz-E1 was 20%. The enzyme specificity was improved significantly. In in vitro assays constructed using recombinant enzymes, (±)-Abz-E2B was a considerably weaker inhibitor than (±)-Abz-E1 for CYP701A, a GA biosynthetic enzyme, which is a target of S-uniconazole (S-UNI), a lead compound of Abz-E1. (±)-Abz-E2B application to plants resulted in improved desiccation tolerance and an increase in endogenous ABA, with little retardation of growth. We also prepared optically pure Abz-E2B and determined its absolute configuration. The R-enantiomer of Abz-E2B was the more potent inhibitor of CYP707A, unlike UNI, whereas both enantiomers were markedly less effective than S-UNI in inhibiting CYP701A. Because S-Abz-E2B arrested the growth of rice seedlings at 100 µM, probably because of off-target effects, R-Abz-E2B should be used as a chemical tool for research focusing on CYP707A when 100 µM or higher concentration is required, although (±)-Abz-E2B may be useful as an alternative option at a lower concentration.
Assuntos
Inibidores das Enzimas do Citocromo P-450 , Oryza/efeitos dos fármacos , Triazóis/química , Triazóis/farmacologia , Sistema Enzimático do Citocromo P-450 , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Estrutura Molecular , Oryza/crescimento & desenvolvimento , Proteínas de Plantas , Plântula/efeitos dos fármacos , Solubilidade , Especificidade por Substrato , Água/químicaRESUMO
The plant growth retardant uniconazole (UNI), which has been used as an effective inhibitor of ent-kaurene oxidase (CYP701A) involved in gibberellin biosynthesis, also strongly inhibits ABA 8'-hydroxylase (CYP707A), a key enzyme in abscisic acid catabolism. Azole P450 inhibitors bind to the P450 active site by both coordinating to the heme-iron atom via an sp(2) nitrogen and interacting with surrounding protein residues through a lipophilic region. We hypothesized that poor selectivity of UNI may result from its small molecular size and flexible conformation that allows it to fit into active sites differing in size and shape. To find a selective inhibitor of CYP701A based on this hypothesis, we examined inhibitory activities of three types of UNI analogues, which were conformationally constrained, enlarged in width, and enlarged in length, against recombinant rice CYP701A6 and Arabidopsis CYP707A3. Conformationally restricted analogues, UFAP2 and UFAP2N, inhibited CYP701A6 as strongly as UNI, whereas it inhibited CYP707A3 less than UNI.
Assuntos
Inibidores das Enzimas do Citocromo P-450 , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Oryza/enzimologia , Triazóis/química , Triazóis/farmacologia , Sistema Enzimático do Citocromo P-450 , Conformação Molecular , Especificidade por SubstratoRESUMO
The effects of an abscisic acid (ABA) 8'-hydroxylase inhibitor (Abz-F1) on ABA catabolism, stomatal aperture, and water potential were examined in apple seedlings under dehydration and rehydration conditions. In this study, 9-cis-epoxycarotenoid dioxigenase (MdNCED) and ABA 8'-hydroxylase (MdCYP707A) genes were isolated and their expressions were investigated under dehydration and rehydration conditions. The stomatal aperture decreased up to 4 h after spraying with Abz-F1 and the stomatal aperture in the Abz-F1-treated leaves was generally lower than that in the untreated control-leaves during the dehydration condition. Although the water potential in untreated control-leaves decreased with the progress of dehydration, it was maintained at a higher level in the Abz-F1 treated-leaves than in the untreated control-leaves during dehydration. Endogenous ABA concentrations increased with dehydration in both the Abz-F1 treated- and untreated-control-leaves, but the ABA levels in the Abz-F1 treated-leaves were higher than those in the untreated control-leaves throughout dehydration. In contrast, the phaseic acid (PA) concentrations in the Abz-F1 treated-leaves were lower than those in the untreated control-leaves during dehydration. The expressions of MdNCEDs in the Abz-F1 treated-leaves were lower than those in the untreated control-leaves regardless of the higher endogenous ABA concentrations. Moreover, the expressions of MdCYP707As in the Abz-F1 treated-leaves were also lower than those in the untreated control-leaves. Higher 50% effective concentrations (EC(50)) and ascorbic acid concentrations were observed in the Abz-F1 treated-leaves, which show that the oxidative damage under dehydration may be reduced by Abz-F1 application. These results suggest that prompt stomata closure is required for survival under dehydration, and Abz-F1 application may therefore be of practical use. The increase of endogenous ABA, which induced prompt stomata closure in Abz-F1 treated-leaves may depend on inhibition of the expression of MdCYP707As. Furthermore, the results showed the close relationship between MdNCEDs and MdCYP707As on ABA catabolism.
Assuntos
Inibidores das Enzimas do Citocromo P-450 , Desidratação/metabolismo , Inibidores Enzimáticos/metabolismo , Malus/metabolismo , Ácido Abscísico/metabolismo , Sistema Enzimático do Citocromo P-450/metabolismo , Malus/crescimento & desenvolvimento , Reguladores de Crescimento de Plantas/metabolismo , Proteínas de Plantas , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Água/metabolismoRESUMO
We prepared 19 amino acid conjugates of the plant hormone abscisic acid (ABA) and investigated their biological activity, enzymatic hydrolysis by a recombinant Arabidopsis amidohydrolases GST-ILR1 and GST-IAR3, and metabolic fate in rice seedlings. Different sets of ABA-amino acids induced ABA-like responses in different plants. Some ABA-amino acids, including some that were active in bioassays, were hydrolyzed by recombinant Arabidopsis GST-IAR3, although GST-ILR1 did not show hydrolysis activity for any of the ABA-amino acids. ABA-L-Ala, which was active in all the bioassays, an Arabidopsis seed germination, spinach seed germination, and rice seedling elongation assays, except in a lettuce seed germination assay and was hydrolyzed by GST-IAR3, was hydrolyzed to free ABA in rice seedlings. These findings suggest that some plant amidohydrolases hydrolyze some ABA-amino acid conjugates. Because our study indicates the possibility that different plants have hydrolyzing activity toward different ABA-amino acids, an ABA-amino acid may function as a species-selective pro-hormone of ABA.
Assuntos
Ácido Abscísico , Aminoácidos , Ácido Abscísico/síntese química , Ácido Abscísico/química , Ácido Abscísico/metabolismo , Ácido Abscísico/farmacologia , Aminoácidos/síntese química , Aminoácidos/química , Aminoácidos/metabolismo , Aminoácidos/farmacologia , Proteínas de Arabidopsis/metabolismo , Germinação , Concentração Inibidora 50 , Estrutura Molecular , Oryza/metabolismo , Reguladores de Crescimento de Plantas/química , Reguladores de Crescimento de Plantas/metabolismo , Sementes/crescimento & desenvolvimento , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
We developed abscinazole-E1 (Abz-E1), a specific inhibitor of abscisic acid (ABA) 8'-hydroxylase (CYP707A). This inhibitor was designed and synthesized as an enlarged analogue of uniconazole (UNI), a well-known plant growth retardant, which inhibits a gibberellin biosynthetic enzyme (ent-kaurene oxidase, CYP701A) as well as CYP707A. Our results showed that Abz-E1 functions as a potent inhibitor of CYP707A and a poor inhibitor of CYP701A both in vitro and in vivo. Abz-E1 application to plants resulted in improved desiccation tolerance and an increase in endogenous ABA.
Assuntos
Sistema Enzimático do Citocromo P-450/química , Sistema Enzimático do Citocromo P-450/metabolismo , Triazóis/química , Arabidopsis/enzimologia , Arabidopsis/fisiologia , Germinação , Oryza/enzimologia , Oryza/fisiologia , Proteínas de PlantasRESUMO
Thoroughbred horses are seasonal mating animals, raised in northern regions or countries. Foals born yearly in spring generally show a typical seasonal compensatory growth pattern, in which their growth rate declines in the first winter and increases in the next spring. In this study, a new empirical adjustment approach is proposed to adjust for this compensatory growth when growth curve equations are estimated, by using 1,633 male body weights of Thoroughbreds as an illustrating example. Based on general Richards growth curve equation, a new growth curve equation was developed and fit to the weight-age data. The new growth curve equation had a sigmoid sub-function that can adjust the compensatory growth, combined with the Richards biological parameter responsible for the maturity of animals. The unknown parameters included in the equations were estimated by SAS NLMIXED procedure. The goodness of fit was examined by using Akaike's Information Criterion (AIC). The AIC values decreased from 13,053 (general Richards equation) to 12,794 (the newly developed equation), indicating the better fit of the new equation to the weight-age data. The shape of the growth curve was improved during the period of compensatory growth. The proposed method is one of the useful approaches for adjusting seasonal compensatory growth in growth curve estimations for Thoroughbreds, and for their management during the compensatory period. Based on this approach, the optimal growth curve equations can be estimated also for female body weight of Thoroughbreds or other growth traits affected by seasonal compensatory growth.
RESUMO
The plant growth-retardant uniconazole (UNI), a triazole inhibitor of gibberellin biosynthetic enzyme (CYP701A), inhibits multiple P450 enzymes including ABA 8'-hydroxylase (CYP707A), a key enzyme in ABA catabolism. Azole P450 inhibitors bind to a P450 active site by both coordinating to the heme-iron atom via sp2 nitrogen and interacting with surrounding protein residues through a lipophilic region. We hypothesized that poor selectivity of UNI may result from adopting a distinct conformation and orientation for different active sites. Based on this hypothesis, we designed and synthesized novel UNI analogs with a disubstituted azole ring (DSI). These analogs were expected to have higher selectivity than UNI because the added functional group may interact with the active site to restrict orientation of the molecule in the active site. DSI-505ME and DSI-505MZ, which have an imidazolyl group with a methyl 5-acrylate, strongly inhibited recombinant CYP707A3, with no growth-retardant effect.