RESUMEN
Two-phase flow separation is a key step in various downstream purification processes. The use of a separator with controllable flow behavior is recommended to avoid contamination. In this study, a core-annular separator for biphasic flow separation with four different chemical polarities was developed, and two machine learning-based methods were proposed for answering two emergent questions to meet real industrial needs. (1) Could complete two-phase separation be achieved under these operating conditions? (2) Could the separation process be accelerated by determining the maximum input flow rate of the water? Process prediction for automation, machine learning-based classifiers, and multilayer perceptron were used to address these questions by predicting successful separation and the maximum input flow rates of unknown water-solvent systems with limited experimental data as training samples. The core-annular separator achieved complete two-phase water-solvent separation at a maximum total input flow rate of 4000 µL min-1. Moreover, the classification accuracy for complete separation reached 92.2%, and the multilayer perceptron network had the best performance for predicting the flow rate. This liquid-liquid interface manipulation separator and machine learning method could decrease the cost of relevant process development.
RESUMEN
Tourette Syndrome (TS) is a heritable, early-onset neuropsychiatric disorder that typically begins in early childhood. Identifying rare genetic variants that make a significant contribution to risk in affected families may provide important insights into the molecular aetiology of this complex and heterogeneous syndrome. Here we present a whole-genome sequencing (WGS) analysis from the 11-generation pedigree (>500 individuals) of a densely affected Costa Rican family which shares ancestry from six founder pairs. By conducting an identity-by-descent (IBD) analysis using WGS data from 19 individuals from the extended pedigree we have identified putative risk haplotypes that were not seen in controls, and can be linked with four of the six founder pairs. Rare coding and non-coding variants present on the haplotypes and only seen in haplotype carriers show an enrichment in pathways such as regulation of locomotion and signal transduction, suggesting common mechanisms by which the haplotype-specific variants may be contributing to TS-risk in this pedigree. In particular we have identified a rare deleterious missense variation in RAPGEF1 on a chromosome 9 haplotype and two ultra-rare deleterious intronic variants in ERBB4 and IKZF2 on the same chromosome 2 haplotype. All three genes play a role in neurodevelopment. This study, using WGS data in a pedigree-based approach, shows the importance of investigating both coding and non-coding variants to identify genes that may contribute to disease risk. Together, the genes and variants identified on the IBD haplotypes represent biologically relevant targets for investigation in other pedigree and population-based TS data.
Asunto(s)
Neurogénesis , Síndrome de Tourette , Preescolar , Humanos , Costa Rica , Haplotipos , Linaje , Transducción de Señal , Síndrome de Tourette/genética , Neurogénesis/genética , Polimorfismo Genético , Secuenciación Completa del Genoma , Factor 2 Liberador de Guanina Nucleótido/genéticaRESUMEN
This Letter reports on the first results from the Taiwan Axion Search Experiment with a Haloscope, a search for axions using a microwave cavity at frequencies between 4.707 50 and 4.798 15 GHz. Apart from the nonaxion signals, no candidates with a significance of more than 3.355 were found. The experiment excludes models with the axion-two-photon coupling |g_{aγγ}|â³8.1×10^{-14} GeV^{-1}, a factor of eleven above the benchmark Kim-Shifman-Vainshtein-Zakharov model, in the mass range 19.4687
RESUMEN
We report on a holoscope axion search experiment near 19.6 µeV from the Taiwan Axion Search Experiment with Haloscope collaboration. This experiment is carried out via a frequency-tunable cavity detector with a volume V = 0.234 liter in a magnetic field B0 = 8 T. With a signal receiver that has a system noise temperature Tsys â 2.2 K and an experiment time of about one month, the search excludes values of the axion-photon coupling constant gaγγ â³ 8.1 × 10-14 GeV-1, a factor of 11 above the Kim-Shifman-Vainshtein-Zakharov benchmark model, at the 95% confidence level in the mass range of 19.4687-19.8436 µeV. We present the experimental setup and procedures to accomplish this search.
RESUMEN
Chronic obstructive pulmonary disease (COPD) is a progressive lung disease with high morbidity and mortality worldwide. Although several mechanisms to account for deleterious immune effects were proposed, molecular description for the underlying alveolar structural alterations for COPD is lacking. Here, silencing of α1,6-fucosyltransferase (Fut8), the enzyme for core-fucosylation and highly expressed in lung stem cells, resulted in alveolar structural changes in lung organoids, recapitulating COPD. Site-specific mass spectrometry analysis demonstrated that the secreted protein acidic and rich in cysteine (SPARC), which binds collagen, contains a core-fucosylation site in its VCSNDNcfK glycopeptide. Biacore assay showed markedly reduced collagen binding of SPARC lacking core fucosylation. Molecular dynamics analysis revealed that core fucosylation of SPARC-induced dynamic conformational changes in its N-glycan, allowing terminal galactose and N-acetylglucosamine to interact with K150, P261 and H264 residues, thereby promoting collagen binding. Site-specific mutagenesis of these residues also resulted in low affinity for collagen binding. Moreover, loss of collagen and decline of core fucosylation were observed in COPD lung tissues. These findings provide a new mechanistic insight into the role of core fucosylation of SPARC in cell-matrix communication and contribution to the abnormal alveolar structures in COPD.
Asunto(s)
Osteonectina , Enfermedad Pulmonar Obstructiva Crónica , Colágeno/metabolismo , Fucosiltransferasas/genética , Fucosiltransferasas/metabolismo , Glicosilación , Humanos , Osteonectina/genética , Osteonectina/metabolismo , Enfermedad Pulmonar Obstructiva Crónica/genéticaRESUMEN
This study investigates an association between obesity and cardiorespiratory fitness concerning their potential effects on cognitive flexibility in young adults from behavioral and neuroelectrical perspectives. Eligible young adults (N = 140, 18-25 years) were assigned into one of four groups, according to their status of obesity (i.e., body mass index) and cardiorespiratory fitness levels (i.e., estimated maximal oxygen uptake), namely, normal weight with high cardiorespiratory fitness (NH), obese with high cardiorespiratory fitness (OH), normal weight with low cardiorespiratory fitness (NL), and obese with low cardiorespiratory fitness (OL). The task-switching test was utilized, and its induced endogenous (P3) and exogenous (N1) event-related potential components were recorded. Concerning behavioral indices, the NH demonstrated superior behavioral performance across global switching and local switching of the task-switching test compared to individuals with lower cardiorespiratory fitness and obesity (i.e., NL, OH, and OL). Additionally, the OH demonstrated better performance than the OL during the heterogeneous condition. For neuroelectrical indices, the NH had larger mean P3 amplitudes during global and local switching than the other three groups. A larger N1 amplitude was also observed in the NH during local switching than in the OH group. The findings suggest that cardiorespiratory fitness has beneficial effects on cognitive flexibility, attentional resource allocation, and sensory evaluation in young adults. Furthermore, our research provided novel evidence showing that cardiorespiratory fitness might potentially alleviate the adverse effects of obesity on cognitive flexibility in young adults.
RESUMEN
Puf-A, a nucleolar Puf domain protein, is required for ribosome biogenesis. A study of Puf-A in zebrafish has shown that Puf-A is highly expressed in primordial germ cells (PGCs) and participates in PGC development. However, it remains unclear how Puf-A governs PGC development in mammals. Here, we generated transgenic mice carrying inducible Puf-A shRNA and obtained double heterozygous mice with Puf-A shRNA and Oct4-EGFP to examine the behavior of PGCs. It was found that the knockdown of Puf-A led to the loss of a considerable number of PGCs and a slowdown of the movement of the remaining PGCs. Puf-A and NPM1 colocalized in clusters in the nuclei of the PGCs. The silencing of Puf-A resulted in the translocation of NPM1 from nucleolus to nucleoplasm and the hyperactivation of p53 in the PGCs. The PGCs in Puf-A knockdown embryos showed a significant increase in subpopulations of PGCs at G1 arrest and apoptosis. Moreover, the expression of essential genes associated with PGC maintenance was decreased in the Puf-A knockdown PGCs. Our study showed that Puf-A governed PGC development by regulating the growth, survival, and maintenance of PGCs. We also observed the alterations of NPM1 and p53 upon Puf-A knockdown to be consistent with the previous study in cancer cells, which might explain the molecular mechanism for the role of Puf-A in PGC development.
Asunto(s)
Células Germinativas , Proteínas de Unión al ARN/metabolismo , Proteínas de Pez Cebra/metabolismo , Pez Cebra , Animales , Diferenciación Celular , Células Germinativas/metabolismo , Mamíferos , Ratones , ARN Interferente Pequeño/metabolismo , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/metabolismoRESUMEN
IL-20 is a proinflammatory cytokine of the IL-10 family and involved in several diseases. However, the regulatory role of IL-20 in obesity is not well understood. We explored the function of IL-20 in the pathogenesis of obesity-induced insulin resistance by ELISA, Western blotting and flow cytometry. The therapeutic potential of IL-20 monoclonal antibody 7E for ameliorating diet-induced obesity was analysed in murine models. Higher serum IL-20 levels were detected in obese patients. It was upregulated in leptin-deficient (ob/ob), leptin-resistant (db/db) and high-fat diet (HFD)-induced murine obesity models. In vitro, IL-20 regulated the adipocyte differentiation and the polarization of bone marrow-derived macrophages into proinflammatory M1 type. It also caused inflammation and macrophage retention in adipose tissues by upregulating TNF-α, monocyte chemotactic protein 1 (MCP-1), netrin 1 and unc5b (netrin receptor) expression in macrophages and netrin 1, leptin and MCP-1 in adipocytes. IL-20 promoted insulin resistance by inhibiting glucose uptake in mature adipocytes through the SOCS-3 pathway. In HFD-induced obesity in mice, 7E treatment reduced body weight and improved glucose tolerance and insulin sensitivity; it also reduced local inflammation and the number of M1-like macrophages in adipose tissues. We have identified a critical role of IL-20 in obesity-induced inflammation and insulin resistance, and we conclude that IL-20 may be a novel target for treating obesity and insulin resistance in patients with metabolic disorders.
Asunto(s)
Adipogénesis , Susceptibilidad a Enfermedades , Interleucinas/metabolismo , Macrófagos/metabolismo , Obesidad/etiología , Obesidad/metabolismo , Adipocitos/metabolismo , Adipogénesis/genética , Adulto , Anciano , Anciano de 80 o más Años , Animales , Biomarcadores , Quimiotaxis de Leucocito , Citocinas/metabolismo , Modelos Animales de Enfermedad , Femenino , Expresión Génica , Glucosa/metabolismo , Humanos , Insulina/metabolismo , Interleucinas/genética , Macrófagos/inmunología , Masculino , Ratones , Persona de Mediana Edad , Obesidad/patología , Transducción de SeñalRESUMEN
This study investigated the effects of a mindfulness-based intervention (MBI) called mindfulness-based peak performance (MBPP) on athletic performance and cognitive functions in archers, as well as the role of psychological status and the dose-response relationship of MBPP in archery performance. Twenty-three archers completed a simulated archery competition and the Stroop task prior to and after MBPP training, which consisted of eight sessions over four weeks, while the mindfulness and rumination levels of the archers were assessed at three time points, namely, before, at the mid-point of, and after the MBPP program. The results revealed that the MBPP program significantly improved the shooting performance (p = 0.002, d = 0.27), multiple cognitive functions (ps < 0.001, d = 0.51~0.71), and mindfulness levels of the archers on the post-test, compared to the pre-test (p = 0.032, η p 2 = 0.15 for general; p = 0.004, η p 2 = 0.22 for athletic). Additionally, negative ruminations level was decreased from the pre-test to the middle-test and post-test (ps < 0.001, η p 2 = 0.43). These findings provide preliminary evidence to support the view that MBPP could serve as a promising form of training for fine motor sport performance, cognitive functions, and specific psychological status, such that it warrants further study.
RESUMEN
Stem cell activity and cell differentiation is robustly influenced by the nutrient availability in the gonads. The signal that connects nutrient availability to gonadal stem cell activity remains largely unknown. In this study, we show that tumor necrosis factor Eiger (Egr) is upregulated in testicular smooth muscles as a response to prolonged protein starvation in Drosophila testis. While Egr is not essential for starvation-induced changes in germline and somatic stem cell numbers, Egr and its receptor Grindelwald influence the recovery dynamics of somatic cyst stem cells (CySCs) upon protein refeeding. Moreover, Egr is also involved in the refeeding-induced, ectopic expression of the CySC self-renewal protein and the accumulation of early germ cells. Egr primarily acts through the Jun N-terminal kinase (JNK) signaling in Drosophila. We show that inhibition of JNK signaling in cyst cells suppresses the refeeding-induced abnormality in both somatic and germ cells. In conclusion, our study reveals both beneficial and detrimental effects of Egr upregulation in the recovery of stem cells and spermatogenesis from prolonged protein starvation.
Asunto(s)
Proteínas en la Dieta/metabolismo , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Proteínas Quinasas JNK Activadas por Mitógenos/genética , Proteínas de la Membrana/genética , Espermatozoides/metabolismo , Células Madre/metabolismo , Animales , Diferenciación Celular , Proteínas en la Dieta/administración & dosificación , Proteínas de Drosophila/agonistas , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/citología , Drosophila melanogaster/crecimiento & desarrollo , Drosophila melanogaster/metabolismo , Ingestión de Alimentos/fisiología , Regulación del Desarrollo de la Expresión Génica , Homeostasis/genética , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Sistema de Señalización de MAP Quinasas , Masculino , Proteínas de la Membrana/agonistas , Proteínas de la Membrana/metabolismo , Espermatogénesis/efectos de los fármacos , Espermatogénesis/genética , Espermatozoides/citología , Espermatozoides/efectos de los fármacos , Inanición/genética , Inanición/metabolismo , Nicho de Células Madre/genética , Células Madre/citología , Células Madre/efectos de los fármacos , Testículo/citología , Testículo/efectos de los fármacos , Testículo/crecimiento & desarrollo , Testículo/metabolismoRESUMEN
Transposons are known to participate in tissue aging, but their effects on aged stem cells remain unclear. Here, we report that in the Drosophila ovarian germline stem cell (GSC) niche, aging-related reductions in expression of Piwi (a transposon silencer) derepress retrotransposons and cause GSC loss. Suppression of Piwi expression in the young niche mimics the aged niche, causing retrotransposon depression and coincident activation of Toll-mediated signaling, which promotes Glycogen synthase kinase 3 activity to degrade ß-catenin. Disruption of ß-catenin-E-cadherin-mediated GSC anchorage then results in GSC loss. Knocking down gypsy (a highly active retrotransposon) or toll, or inhibiting reverse transcription in the piwi-deficient niche, suppresses GSK3 activity and ß-catenin degradation, restoring GSC-niche attachment. This retrotransposon-mediated impairment of aged stem cell maintenance may have relevance in many tissues, and could represent a viable therapeutic target for aging-related tissue degeneration.
Asunto(s)
Proteínas Argonautas/metabolismo , Senescencia Celular , Proteínas de Drosophila/metabolismo , Drosophila melanogaster , Células Germinativas/metabolismo , Animales , Proteínas Argonautas/genética , Cadherinas/metabolismo , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Femenino , Silenciador del Gen , Glucógeno Sintasa Quinasa 3/metabolismo , Ovario/citología , Ovario/metabolismo , Retroelementos/genética , Transducción de Señal , Nicho de Células Madre/fisiología , Células Madre/metabolismo , Receptores Toll-Like/metabolismo , beta Catenina/metabolismoRESUMEN
Stem cells rely on instructive cues from their environment. Alterations in microenvironments might contribute to tissue dysfunction and disease pathogenesis. Germline stem cells (GSCs) and cyst stem cells (CySC) in Drosophila testes are normally maintained in the apical area by the testicular hub. In this study, we found that reproduction leads to accumulation of early differentiating daughters of CySCs and GSCs in the testes of aged male flies, due to hyperactivation of Jun-N-terminal kinase (JNK) signaling to maintain self-renewal gene expression in the differentiating cyst cells. JNK activity is normally required to maintain CySCs in the apical niche. A muscle sheath surrounds the Drosophila testis to maintain its long coiled structure. Importantly, reproduction triggers accumulation of the tumor necrosis factor (TNF) Eiger in the testis muscle to activate JNK signaling via the TNF receptor Grindelwald in the cyst cells. Reducing Eiger activity in the testis muscle sheath suppressed reproduction-induced differentiation defects, but had little effect on testis homeostasis of unmated males. Our results reveal that reproduction in males provokes a dramatic shift in the testicular microenvironment, which impairs tissue homeostasis and spermatogenesis in the testes.
Asunto(s)
Células Madre Germinales Adultas/citología , Drosophila melanogaster/fisiología , Reproducción , Células Madre Germinales Adultas/metabolismo , Animales , Diferenciación Celular , Autorrenovación de las Células , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/citología , Femenino , Homeostasis , Sistema de Señalización de MAP Quinasas , Masculino , Proteínas de la Membrana/metabolismo , Conducta Sexual Animal , Espermatogénesis , Nicho de Células Madre , Testículo/citología , Testículo/metabolismoRESUMEN
A key aspect of germ cell development is to establish germline sexual identity and initiate a sex-specific developmental program to promote spermatogenesis or oogenesis. Previously, we have identified the histone reader Plant Homeodomain Finger 7 (PHF7) as an important regulator of male germline identity. To understand how PHF7 directs sexual differentiation of the male germline, we investigated the downstream targets of PHF7 by combining transcriptome analyses, which reveal genes regulated by Phf7, with genomic profiling of histone H3K4me2, the chromatin mark that is bound by PHF7. Through these genomic experiments, we identify a novel spermatocyte factor Receptor Accessory Protein Like 1 (REEPL1) that can promote spermatogenesis and whose expression is kept off by PHF7 in the spermatogonial stage. Loss of Reepl1 significantly rescues the spermatogenesis defects in Phf7 mutants, indicating that regulation of Reepl1 is an essential aspect of PHF7 function. Further, increasing REEPL1 expression facilitates spermatogenic differentiation. These results indicate that PHF7 controls spermatogenesis by regulating the expression patterns of important male germline genes.
Asunto(s)
Proteínas de Drosophila/genética , Proteínas de Homeodominio/genética , Espermatocitos/metabolismo , Espermatogénesis/genética , Animales , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/citología , Drosophila melanogaster/genética , Drosophila melanogaster/crecimiento & desarrollo , Histonas/metabolismo , Proteínas de Homeodominio/metabolismo , Masculino , Espermatocitos/citologíaRESUMEN
AIMS: Activation of glomerular mesangial cells (MCs) and functional changes of renal tubular cells are due to metabolic abnormalities, oxidative stress, and matrix accumulation in the diabetic nephropathy (DN). Aryl hydrocarbon receptor (AhR) activation has been implicated in DN. In this study, we investigated the role of AhR in the pathophysiological processes of DN using AhR knockout (AhRKO) and pharmacological inhibitor α-naphthoflavone mouse models. RESULTS: The increased blood glucose, glucose intolerance, MC activation, macrophage infiltration, and extracellular matrix (ECM) accumulation were significantly attenuated in AhRKO mice with diabetic inducer streptozotocin (STZ) treatment. AhR deficiency by genetic knockout or pharmacological inhibition also decreased the induction of cyclooxygenase-2 (COX-2)/prostaglandin E2 (PGE2), lipid peroxidation, oxidative stress, NADPH oxidase activity, and N-É-carboxymethyllysine (CML, a major advanced glycation end product) in STZ-induced diabetic mice. CML showed remarkably increased AhR/COX-2 DNA-binding activity, protein-DNA interactions, gene regulation, and ECM formation in MCs and renal proximal tubular cells, which could be reversed by siRNA-AhR transfection. CML-increased AhR nuclear translocation and biological activity in MCs and renal proximal tubular cells could also be effectively attenuated by antioxidants. INNOVATION: We elucidate for the first time that AhR plays an important role in MC activation, macrophage infiltration, and ECM accumulation in DN conferred by oxidative stress. CONCLUSIONS: AhR-regulated COX-2/PGE2 expression and ECM deposition through oxidative stress cascade is involved in the CML-triggered MC activation and macrophage infiltration. These findings suggest new insights into the development of therapeutic approaches to reduce diabetic microvascular complications. Antioxid. Redox Signal. 24, 217-231.
Asunto(s)
Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/deficiencia , Nefropatías Diabéticas/metabolismo , Matriz Extracelular/patología , Macrófagos/patología , Células Mesangiales/patología , Especies Reactivas de Oxígeno/metabolismo , Receptores de Hidrocarburo de Aril/deficiencia , Animales , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Benzoflavonas/farmacología , Glucemia/metabolismo , Diabetes Mellitus Experimental/complicaciones , Nefropatías Diabéticas/genética , Matriz Extracelular/efectos de los fármacos , Matriz Extracelular/metabolismo , Regulación de la Expresión Génica/efectos de los fármacos , Peroxidación de Lípido/efectos de los fármacos , Macrófagos/metabolismo , Células Mesangiales/efectos de los fármacos , Células Mesangiales/metabolismo , Ratones , Estrés Oxidativo/efectos de los fármacos , Receptores de Hidrocarburo de Aril/genética , EstreptozocinaRESUMEN
The aim of this research was to investigate the hyphal growth-promoting factors (HGFs) of Antrodia camphorata from the host-related species, Cinnamomum camphora (CC) and the underlying chemical produced. The HGF was identified in the polysaccharide fraction of CC at levels ranging from 80 to 320 mg L(-1), and it maximally stimulated growth to 5.50 g L(-1) during a 14-day culture period compared to that of the control of 2.88 g L(-1). We also investigated the nature and chemical composition of the CC polysaccharide. Herein, size-exclusion column chromatography followed by high-performance anion-exchange chromatography after complete hydrolysis of the CC polysaccharide was performed to derive its molecular weight and sugar composition. The Mw values of the CC polysaccharide were determined to be 728.2, 187.5, 28.7, 7.5, and 1.9 kDa. Compositional analysis of the CC polysaccharide showed that galactosamine, mannose, and glucose were the major monosaccharides. Time-course studies of mycelial extracts of cultures revealed that prolonged incubation with the water-soluble extracts of CC resulted in an increase in the relative amounts of two lanostane-type compounds, i.e., dehydrosulphurenic acid and 15alpha-acetyl-dehydrosulphurenic acid, which are found in the fruiting bodies of A. camphorata. This finding offers the possibility of the reliable production of this medicinal fungus under laboratory conditions compared to its limited slow growth in nature.
Asunto(s)
Cinnamomum camphora/química , Polyporales/crecimiento & desarrollo , Polisacáridos/aislamiento & purificación , Extractos Celulares/farmacología , Cromatografía Líquida de Alta Presión , Hifa/crecimiento & desarrollo , Peso Molecular , Tamaño de la Partícula , Polyporales/fisiología , Polisacáridos/análisis , Polisacáridos/farmacología , Solubilidad , Factores de TiempoRESUMEN
Extract: Radiation has become a mainstay therapy and currently provides care for approximately one half of the cancer population since its discovery more than a century ago. However, the efficacy of radiotherapy is largely restricted by the radiation-associated side effects, which in a way reflects the lack of tumor specificity of radiation. Drugs targeting DNA topoisomerase I (TOP1) are a novel class of anticancer agents with established activity against many cancers. In addition to their ability to kill cancer cells directly, these drugs are also excellent radiation sensitizers that can enhance the cell-killing effect of radiation. Combining TOP1-targeted drugs and radiotherapy represents a new promising cancer therapy. Here, we briefly review, from basic science to clinical application, the current status of targeted radiosensitization (RS) by combining TOP1 drugs with radiation.
RESUMEN
Although Al-induced iron chlorosis has been observed in many plants, the mechanisms responsible for this phenomenon are yet to be understood. We investigated the effect of Al on iron acquisition in a Strategy II plant, wheat (Triticum aestivum L.) using both Al-tolerant (Atlas 66) and -sensitive (Scout 66) cultivars. When iron was supplied as insoluble iron, ferric hydroxide, in the culture solution, both cultivars without Al treatment grew normally, while those with 100 µM AlCl3 developed chlorosis of the young leaves after 3 days of the treatment. A 21-h treatment with 100 µM AlCl3 in 0.5 mM CaCl2 solution (pH 4.5) decreased the amount of 2'-deoxymugineic acid (DMA) secreted by Fe-deficient Atlas 66 and Scout 66 plants by 85 and 90%, respectively. The amount of DMA secreted decreased with increasing external Al concentrations. Al treatment during the biosynthesis process caused the inhibition of that of DMA within 3 h. The secretion process was also found to be inhibited by Al, resulting in the biosynthesized DMA remaining in the roots. These results demonstrate the inhibition by Al of both biosynthesis and secretion of DMA attributed to Al-induced iron chlorosis.