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OBJECTIVE: To investigate the relationship between the sensitization state of acupoints on the surface of the myocardial ischemia (MI) model mice and the changes in the electrophysiological properties of the dorsal root ganglion (DRG) neurons in the corresponding spinal cord segment, and its underlying mechanism. METHODS: Sixty-eight male C57BL/6J mice were randomly divided into control and model groups (34 mice in each group). The model group received an intraperitoneal injection of 160 mg/kg isoproterenol (ISO) to establish the MI model, and the control group received an injection of the same dose of normal saline as the model group. After modeling for about 6 days, MI proportion was measured by HE staining to verify the pathological changes in the heart tissue. Evans blue (EB) dye was injected into the tail vein of mice to reflect the size, location, distribution, and number of exudates on the body surface. Then, whole-cell membrane currents, intrinsic excitability and membrane properties of different types of DRG neurons were evaluated by electrophysiological experiment in vitro. RESULTS: Compared with the control group, the heart size was larger, with pathological outcomes showing enlarged myocardial hypertrophy, destroyed structure of cardiomyocytes, with mononuclear cell infiltration among the cardiomyocytes in the model group. Compared with the control group, the number of EB exudation points was significantly increased (P<0.01), which were mainly concentrated in the epidermis near the T1-T5 segment of the spinal cord, "Feishu" (BL13), "Jueyinshu" (BL14) and "Xinshu" (BL15) in the model group. Compared with the control group, the rheobase and action potential amplitude (APA) of DRG medium-sized neurons were obviously decreased (P<0.01, P<0.05), while the whole-cell membrane currents, the spike numbers, the average instantaneous frequency, and the average discharge frequency were markedly increased (P<0.01). There were no significant alterations in the membrane properties and intrinsic excitability induced by depolarized currents of small-sized neurons between groups. Compared with the control group, the whole-cell membrane currents, spike numbers, and the average instantaneous frequency were significantly increased in the model group(P<0.05, P<0.01) while rheobase was significantly decreased (P<0.05) in DRG medium-sized neurons labeled with biotin and CGRP. CONCLUSION: After the mice were modeled by ISO, the DRG medium-size neurons in the T1-T5 segment of the spinal cord may mediate the sensitization of acupoints on the body surface through their different neuronal membrane properties and intrinsic excitabilities.
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Pontos de Acupuntura , Isquemia Miocárdica , Masculino , Animais , Camundongos , Camundongos Endogâmicos C57BL , Gânglios Espinais , Isquemia Miocárdica/terapia , Azul EvansRESUMO
In this study, soy protein isolate (SPI) was modified by a pulsed electric field (PEF) combined with pH shifting treatment (10 kV/cm, pH 11) to prepare SPI nanoparticles (PSPI11) for efficient loading of lutein. The results showed that when the mass ratio of SPI to lutein was 25:1, the encapsulation efficiency of lutein in PSPI11 increased from 54% to 77%, and the loading capacity increased by 41% compared to the original SPI. The formed SPI-lutein composite nanoparticles (PSPI11-LUTNPs) had smaller, more homogeneous sizes and larger negative charges than SPI7-LUTNPs. The combined treatment favored the unfolding of the SPI structure and could expose its interior hydrophobic groups to bind with lutein. Nanocomplexation with SPIs significantly improved the solubility and stability of lutein, with PSPI11 showing the greatest improvement. As a result, PEF combined with pH shifting pretreatment is an effective method for developing SPI nanoparticles loaded and protected with lutein.
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Nanopartículas , Proteínas de Soja , Proteínas de Soja/química , Luteína , Nanopartículas/química , Interações Hidrofóbicas e Hidrofílicas , Concentração de Íons de HidrogênioRESUMO
OBJECTIVE: To investigate the relationship between acupoint sensitization on the body surface and neuronal intrinsic excitability of the medium- and small-size dorsal root ganglion (DRG) neurons from the perspective of ion channel kinetics in mice with gastric ulcer. METHODS: Male C57BL/6J mice were randomly divided into control (n=32) and model groups (n=34). The gastric ulcer model was established by injection of 60% glacial acetic acid (0.2 mL/100 g) into the gastric wall muscle layer and submucosa near the pylorus in the minor curvature of the stomach. In contrast, the same dose of normal saline was injected in the same way in the control group. Six days after modeling, Evans blue (EB) solution was injected into the mouse's tail vein for observing the number and distribution of the exudation blue spots on the body surface. Histopathological changes of the gastric tissue were observed by H.E. staining. Then, whole-cell membrane currents and intrinsic excitability of medium- and small-size neurons in the spinal T9-T11 DRGs were measured by in vitro electrophysiology combining with biocytin-ABC method. RESULTS: In the control group, EB exudation blue spots were not obvious, while in the model group, the blue spots on the body surface were densely distributed in the area of spinal T9-T11 segments, the epigastric region, and the skin around "Zhongwan" (CV12) and "Huaroumen" (ST24) regions, and near the surgical incision region. Compared with the control group, the model group had a high level of eosinophilic infiltrates in the submucosa of gastric tissues, severe gastric fossa structure damage, gastric fundus gland dilation and other pathological manifestations. The number of exudation blue spots was proportional to the degree of inflammatory reaction in the stomach. In comparison with the control group, the spike discharges of type II of medium-size DRG neurons in T9-T11 segments were decreased, and the current of whole-cell membrane was increased, basic intensity was decreased (P<0.05), discharge frequency and discharge number were increased (P<0.01,P<0.000 1); while the discharges of type I small-size DRG neurons were decreased, those of type II neurons increased, the whole-cell membrane current was decreased, and discharge frequency and discharge number were decreased (P<0.01, P<0.000 1). CONCLUSION: Both the medium- and small-size DRG neurons from the spinal T9-T11 segments involve in gastric ulcer-induced acupoint sensitization via their different spike discharge activities. And intrinsic excitability of these DRG neurons can not only dynamically encode the plasticity of acupoint sensitization, but also can help us understand the neural mechanism of acupoint sensitization induced by visceral injury.
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Gânglios Espinais , Úlcera Gástrica , Ratos , Camundongos , Masculino , Animais , Gânglios Espinais/fisiologia , Úlcera Gástrica/genética , Úlcera Gástrica/terapia , Ratos Sprague-Dawley , Pontos de Acupuntura , Camundongos Endogâmicos C57BL , NeurôniosRESUMO
The partial nitritation-anaerobic ammonium oxidation (anammox; PN-A) process has been considered a sustainable method for wastewater ammonium removal, with recent attempts to treat low-strength wastewater. However, how microbes adapt to the alternate microaerobic-anoxic operation of the process when treating low ammonium concentrations remains poorly understood. In this study, we applied a metagenomic approach to determine the genomic contents of core members in a PN-A reactor treating inorganic ammonium wastewater at loading as low as 0.0192 kg-N/m3/day. The metabolic traits of metagenome-assembled genomes from 18 core species were analyzed. Taxonomically diverse ammonia oxidizers, including two Nitrosomonas species, a comammox Nitrospira species, a novel Chloroflexota-related species, and two anammox bacteria, Ca. Brocadia and Ca. Jettenia, accounted for the PN-A reactions. The characteristics of a series of genes encoding class II ribonucleotide reductase, high-affinity bd-type terminal oxidase, and diverse antioxidant enzymes revealed that comammox Nitrospira has a superior adaptation ability over the competitors, which may confer the privileged partnership with anammox bacteria in the PN-A reactor. This finding is supported by the long-term monitoring experiment, showing the predominance of the comammox Nitrospira in the ammonia-oxidizing community. Metagenomic analysis of seven heterotrophs suggested that nitrate reduction is a common capability in potentially using endogenous carbohydrates and peptides to enhance nitrogen removals. The prevalence of class II ribonucleotide reductase and antioxidant enzymes genes may grant the adaptation to cyclically microaerobic/anoxic environments. The predominant heterotroph is affiliated with Chloroflexota; its genome encodes complete pathways for synthesizing vitamin B6 and methionine. By contrast, other than the two growth factors, Nitrospira and anammox bacteria are complementary to produce various vitamins and amino acids. Besides, the novel Chloroflexota-related ammonia oxidizer lacks corresponding genes for detoxifying the reactive oxygen species and thus requires the aid of co-existing members to alleviate oxidative stress. The analysis results forecast the exchanges of substrates and nutrients as well as the collective alleviation of oxidative stress among the core populations. The new findings of the genomic features and predicted microbial interplay shed light on microbial adaptation to intermittent microaeration specific to the PN-A reactor, which may aid in improving its application to low-strength ammonium wastewater.
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Nitric oxide (NO), as a free radical, is produced by inflamed microglia cells and is one of the destructive factors of the immune system and a factor in myelin degradation. Therefore, inhibition of microglia activity is a chief strategy in reducing neurotoxic damage to the central nervous system. In this study, an herbal Immunomodulatory Drug (IMOD) was used to evaluate the effects of this drug in controlling the amount of nitric oxide. Nitric oxide induction was performed by bacterial lipopolysaccharide (LPS) in rat inflamed microglial cell line, CHME-5. ELISA test was used to measure the produced nitric oxide at 24, 48, and 72 hours. The results showed that the high concentrations of IMOD (1.2, and 4% V/V) had anti-inflammatory effects on microglial cells and were able to reduce the amount of nitric oxide in these cells but the effective dose of IMOD was in the range of 1.2% V/V. Therefore, the safest dose and the best time for the effect of IMOD on inflammatory cell groups are 1.2% V/V and 72h, respectively. Hence, with further studies, IMOD can be considered as an herbal anti-inflammatory drug that is effective in controlling neurodegenerative diseases.
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Agentes de Imunomodulação/farmacologia , Microglia/efeitos dos fármacos , Óxido Nítrico/biossíntese , Extratos Vegetais/farmacologia , Plantas Medicinais/química , Animais , Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Linhagem Celular , Relação Dose-Resposta a Droga , Agentes de Imunomodulação/química , Lipopolissacarídeos/farmacologia , Microglia/citologia , Microglia/metabolismo , Extratos Vegetais/química , Ratos , Fatores de TempoRESUMO
The capability of gut microbiota in degrading foods and drugs administered orally can result in diversified efficacies and toxicity interpersonally and cause significant impact on human health. Production of atherogenic trimethylamine N-oxide (TMAO) from carnitine is a gut microbiota-directed pathway and varies widely among individuals. Here, we demonstrated a personalized TMAO formation and carnitine bioavailability from carnitine supplements by differentiating individual TMAO productivities with a recently developed oral carnitine challenge test (OCCT). By exploring gut microbiome in subjects characterized by TMAO producer phenotypes, we identified 39 operational taxonomy units that were highly correlated to TMAO productivity, including Emergencia timonensis, which has been recently discovered to convert γ-butyrobetaine to TMA in vitro. A microbiome-based random forest classifier was therefore constructed to predict the TMAO producer phenotype (AUROC = 0.81) which was then validated with an external cohort (AUROC = 0.80). A novel bacterium called Ihubacter massiliensis was also discovered to be a key microbe for TMA/TMAO production by using an OCCT-based humanized gnotobiotic mice model. Simply combining the presence of E. timonensis and I. massiliensis could account for 43% of high TMAO producers with 97% specificity. Collectively, this human gut microbiota phenotype-directed approach offers potential for developing precision medicine and provides insights into translational research. Video Abstract.
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Carnitina/farmacologia , Metilaminas/metabolismo , Microbiota/efeitos dos fármacos , Administração Oral , Adulto , Animais , Carnitina/administração & dosagem , Clostridiales/efeitos dos fármacos , Clostridiales/metabolismo , Feminino , Humanos , Masculino , Camundongos , Microbiota/genéticaRESUMO
Spatiotemporally regulated callose deposition is an essential, genetically programmed phenomenon that promotes pollen development and functionality. Severe male infertility is associated with deficient callose biosynthesis, highlighting the significance of intact callose deposition in male gametogenesis. The molecular mechanism that regulates the crucial role of callose in production of functional male gametophytes remains completely unexplored. Here, we provide evidence that the gradual upregulation of a previously uncharacterized cotton (Gossypium hirsutum) pollen-specific SKS-like protein (PSP231), specifically at the post pollen-mitosis stage, activates callose biosynthesis to promote pollen maturation. Aberrant PSP231 expression levels caused by either silencing or overexpression resulted in late pollen developmental abnormalities and male infertility phenotypes in a dose-dependent manner, highlighting the importance of fine-tuned PSP231 expression. Mechanistic analyses revealed that PSP231 plays a central role in triggering and fine-tuning the callose synthesis and deposition required for pollen development. Specifically, PSP231 protein sequesters the cellular pool of RNA-binding protein GhRBPL1 to destabilize GhWRKY15 mRNAs, turning off GhWRKY15-mediated transcriptional repression of GhCalS4/GhCalS8 and thus activating callose biosynthesis in pollen. This study showed that PSP231 is a key molecular switch that activates the molecular circuit controlling callose deposition toward pollen maturation and functionality and thereby safeguards agricultural crops against male infertility.
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Gametogênese/genética , Gametogênese/fisiologia , Glucanos/biossíntese , Gossypium/fisiologia , Proteínas de Plantas/genética , Pólen/crescimento & desenvolvimento , Pólen/genética , Produtos Agrícolas/citologia , Produtos Agrícolas/genética , Produtos Agrícolas/fisiologia , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Glucanos/genética , Gossypium/citologia , Gossypium/genética , Proteínas de Plantas/metabolismo , Pólen/citologia , Pólen/metabolismoRESUMO
BACKGROUND: We developed and validated an artificial intelligence (AI)-assisted prediction of preeclampsia applied to a nationwide health insurance dataset in Indonesia. METHODS: The BPJS Kesehatan dataset have been preprocessed using a nested case-control design into preeclampsia/eclampsia (n = 3318) and normotensive pregnant women (n = 19,883) from all women with one pregnancy. The dataset provided 95 features consisting of demographic variables and medical histories started from 24 months to event and ended by delivery as the event. Six algorithms were compared by area under the receiver operating characteristics curve (AUROC) with a subgroup analysis by time to the event. We compared our model to similar prediction models from systematically reviewed studies. In addition, we conducted a text mining analysis based on natural language processing techniques to interpret our modeling results. FINDINGS: The best model consisted of 17 predictors extracted by a random forest algorithm. Nineâ¼12 months to the event was the period that had the best AUROC in external validation by either geographical (0.88, 95% confidence interval (CI) 0.88-0.89) or temporal split (0.86, 95% CI 0.85-0.86). We compared this model to prediction models in seven studies from 869 records in PUBMED, EMBASE, and SCOPUS. This model outperformed the previous models in terms of the precision, sensitivity, and specificity in all validation sets. INTERPRETATION: Our low-cost model improved preliminary prediction to decide pregnant women that will be predicted by the models with high specificity and advanced predictors. FUNDING: This work was supported by grant no. MOST108-2221-E-038-018 from the Ministry of Science and Technology of Taiwan.
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Aprendizado de Máquina , Modelos Estatísticos , Pré-Eclâmpsia/epidemiologia , Adulto , Pressão Sanguínea , Demografia/estatística & dados numéricos , Feminino , Humanos , Indonésia , Anamnese/estatística & dados numéricos , Programas Nacionais de Saúde/estatística & dados numéricos , GravidezRESUMO
Striatal spiny projection neurons (SPNs) receive convergent excitatory synaptic inputs from the cortex and thalamus. Activation of spatially clustered and temporally synchronized excitatory inputs at the distal dendrites could trigger plateau potentials in SPNs. Such supralinear synaptic integration is crucial for dendritic computation. However, how plateau potentials interact with subsequent excitatory and inhibitory synaptic inputs remains unknown. By combining computational simulation, two-photon imaging, optogenetics, and dual-color uncaging of glutamate and GABA, we demonstrate that plateau potentials can broaden the spatiotemporal window for integrating excitatory inputs and promote spiking. The temporal window of spiking can be delicately controlled by GABAergic inhibition in a cell-type-specific manner. This subtle inhibitory control of plateau potential depends on the location and kinetics of the GABAergic inputs and is achieved by the balance between relief and reestablishment of NMDA receptor Mg2+ block. These findings represent a mechanism for controlling spatiotemporal synaptic integration in SPNs.
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Dendritos/fisiologia , Potenciais Pós-Sinápticos Excitadores/fisiologia , Neurônios/fisiologia , Animais , Córtex Cerebral/metabolismo , Córtex Cerebral/fisiologia , Dendritos/metabolismo , Feminino , Ácido Glutâmico/metabolismo , Masculino , Camundongos , Vias Neurais/metabolismo , Vias Neurais/fisiologia , Neurônios/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Sinapses/metabolismo , Sinapses/fisiologia , Transmissão Sináptica/fisiologia , Tálamo/metabolismo , Tálamo/fisiologia , Ácido gama-Aminobutírico/metabolismoRESUMO
Glycosaminoglycans (GAGs), in particular chondroitin sulfate, are an accepted marker of chondrogenic cells. In this study, a cell-based sulfated GAG assay for identifying the chondrogenesis of mesenchymal stem cells was developed. Based on fluorescent staining using safranin O and 4',6-diamidino-2-phenylindole (DAPI), this method was highly sensitive. The results were both qualitative and quantitative. The method is suitable for identifying the chondrogenic process and also for screening compounds. The method may be helpful for discovering novel bioactive compounds for cartilage regeneration.
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Condrogênese/efeitos dos fármacos , Sulfatos de Condroitina/metabolismo , Avaliação Pré-Clínica de Medicamentos/métodos , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Criança , Sulfatos de Condroitina/química , DNA/química , DNA/metabolismo , Humanos , Indóis/química , Limite de Detecção , Fenazinas/químicaRESUMO
Changes in basal ganglia plasticity at the corticostriatal and thalamostriatal levels are required for motor learning. Endocannabinoid-dependent long-term depression (eCB-LTD) is known to be a dominant form of synaptic plasticity expressed at these glutamatergic inputs; however, whether eCB-LTD can be induced at all inputs on all striatal neurons is still debatable. Using region-specific Cre mouse lines combined with optogenetic techniques, we directly investigated and distinguished between corticostriatal and thalamostriatal projections. We found that eCB-LTD was successfully induced at corticostriatal synapses, independent of postsynaptic striatal spiny projection neuron (SPN) subtype. Conversely, eCB-LTD was only nominally present at thalamostriatal synapses. This dichotomy was attributable to the minimal expression of cannabinoid type 1 (CB1) receptors on thalamostriatal terminals. Furthermore, coactivation of dopamine receptors on SPNs during LTD induction re-established SPN-subtype-dependent eCB-LTD. Altogether, our findings lay the groundwork for understanding corticostriatal and thalamostriatal synaptic plasticity and for striatal eCB-LTD in motor learning.
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Endocanabinoides/metabolismo , Depressão Sináptica de Longo Prazo , Plasticidade Neuronal , Receptor CB1 de Canabinoide/biossíntese , Animais , Gânglios da Base/metabolismo , Gânglios da Base/patologia , Corpo Estriado/metabolismo , Corpo Estriado/patologia , Expressão Gênica , Aprendizagem/fisiologia , Camundongos , Neurônios Motores/metabolismo , Neurônios Motores/patologia , Receptor CB1 de Canabinoide/metabolismo , Sinapses/metabolismo , Sinapses/patologia , Tálamo/metabolismo , Tálamo/patologiaRESUMO
Osteoblast differentiation plays an essential role in bone integrity. Isoflavones and some flavonoids are reported to have osteogenic activity and potentially possess the ability to treat osteoporosis. However, limited information concerning the osteogenic characteristics of hydroxyflavones is available. This study investigates the effects of various hydroxyflavones on osteoblast differentiation in MC3T3-E1 cells. The results showed that 6-hydroxyflavone (6-OH-F) and 7-hydroxyflavone (7-OH-F) stimulated ALP activity. However, baicalein and luteolin inhibited ALP activity and flavone showed no effect. Up to 50 µ M of each compound was used for cytotoxic effects study; flavone, 6-OH-F, and 7-OH-F had no cytotoxicity on MC3T3-E1 cells. Moreover, 6-OH-F activated AKT and serine/threonine kinases (also known as protein kinase B or PKB), extracellular signal-regulated kinases (ERK 1/2), and the c-Jun N-terminal kinase (JNK) signaling pathways. On the other hand, 7-OH-F promoted osteoblast differentiation mainly by activating ERK 1/ 2 signaling pathways. Finally, after 5 weeks of 6-OH-F induction, MC3T3-E1 cells showed a significant increase in the calcein staining intensity relative to merely visible mineralization observed in cells cultured in the osteogenic medium only. These results suggested that 6-OH-F could activate AKT, ERK 1/2, and JNK signaling pathways to effectively promote osteoblastic differentiation.
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Flavonoids are natural compounds derived from plants and some of them have been shown to inhibit osteoclast formation, implicating their potential use for the treatment of osteoporosis. Conventionally, the screening of antiosteoclastic agents is a tedious process that requires visual counting of the number of osteoclasts produced. The purpose of this study was to establish an easier and faster method for screening the antiosteoclastogenic flavonoids by using an enzyme assay. Tartrate-resistant acid phosphatase (TRAP) is a marker enzyme of the osteoclast. Results obtained demonstrated that cellular TRAP activity tended to correlate with the number of osteoclasts formed. However, the secreted TRAP activity was actually responsible for the resorption activities of the functional osteoclasts. Consequently, the effectiveness of antiosteoclastogenic agents was screened for by assessing their inhibition on receptor activator of NF-κB ligand (RANKL)-induced TRAP secretion. The half-inhibitory concentrations of flavonoids on TRAP secretion were employed as indices to compare the effectiveness of various flavonoids. The effective flavonoids also exhibited similar inhibitory potencies in the pit-formation analysis. This protocol provides a rapid analysis to screen for effective antiosteoclastogenic agents.
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Flavonoides/farmacologia , Osteoclastos/citologia , Osteoclastos/efeitos dos fármacos , Fosfatase Ácida/metabolismo , Animais , Contagem de Células , Linhagem Celular , Tamanho Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Feminino , Isoenzimas/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Osteoclastos/metabolismo , Ligante RANK/farmacologia , Fosfatase Ácida Resistente a TartaratoRESUMO
OBJECTIVE: To investigate the distribution characteristics of syndrome types of traditional Chinese medicine (TCM) in essential hypertension and to explore the distribution rule of TCM syndromes. METHODS: A multicenter, large-sample survey method of clinical epidemiology was applied to choose the patients with essential hypertension from North, Middle, and South China. A questionnaire was designed and filled in, then 477 untreated patients with first-diagnosed essential hypertension were selected and the information was recorded into FileMaker database. A cluster analysis method was utilized to study the TCM syndrome distribution rule of essential hypertension. RESULTS: Two-step cluster analysis was done from 3 to 7 clusters. Seven clusters were appropriate, which included deficiency of heart and kidney qi, hyperactivity of liver-yang, deficiency of yin and yang, stagnation of phlegm-dampness, phlegm-heat (subtype of stagnation of phlegm-dampness), blood stasis obstructing collaterals, and other syndromes. The symptoms presenting high percentage in each cluster were more significant in TCM theory. The syndromes of hyperactivity of liver-yang (24.1%) and stagnation of phlegm-dampness (27.1%) presented the high percentages, and deficiency of heart and kidney qi (10.1%), deficiency of yin and yang (8.4%), and blood stasis obstructing collaterals (9.0%) presented the low percentages. CONCLUSION: As compared with the current syndrome differentiation criteria, two-step cluster analysis results not only include the syndromes of deficiency of yin and yang, hyperactivity of liver-yang, stagnation of phlegm-dampness, but also cover qi deficiency and blood stasis.
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Hipertensão , Medicina Tradicional Chinesa/métodos , China , Análise por Conglomerados , Hipertensão Essencial , Humanos , Inquéritos e Questionários , Síndrome , Deficiência da Energia YinRESUMO
Transglutaminases (TGs) are widely distributed enzymes that catalyze posttranslational modification of proteins by Ca(2+)-dependent cross-linking reactions. The family members of TGs participate in many significant processes of biological functions such as tissue regeneration, cell differentiation, apoptosis, and certain pathologies. A novel technique for TG activity assay was developed in this study. It was based on the rapid capturing, fluorescence quenching, and fast separation of the unreacted fluorescent molecules from the macromolecular product with magnetic dextran-coated charcoal. As few as 3 ng of guinea pig liver transglutaminase (gpTG) could be detected by the method; activities of 96 TG samples could be measured within an hour. The K(m) of gpTG determined by this method for monodansylcadaverine (dansyl-CAD) and N, N-dimethylcasein was 14 and 5 muM, respectively. A typical competitive inhibition pattern of cystamine on dansyl-CAD for gpTG activity was also demonstrated. The application of this technique is not limited to the use of dansyl-CAD as the fluorescent substrate of TG; other small fluor-labeled TG substrates may substitute dansyl-CAD. Finally, this method is rapid, highly sensitive, and inexpensive. It is suitable not only for high-throughput screening of enzymes or enzyme inhibitors but also for enzyme kinetic analysis.