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1.
《Cryobiology》2017
Comparative quantitative metabolite profiling can be used for better understanding of cell functions and dysfunctions in particular circumstances such as sperm banking which is an important approach for cryopreservation of endangered species. Cryopreservation techniques have some deleterious effects on spermatozoa which put the obtained results in controversy. Therefore, in the present study, quantitative 1H NMR (Nuclear Magnetic Resonance) based metabolite profiling was conducted to evaluate metabolite changes related to energetics and some other detected metabolites in vitrified semen of critically endangered wild Acipenser persicus. The semen was diluted with extenders containing 0, 5, 10, and 15 μM of fish antifreeze protein (AFP) type III as a cryoprotectant. Semen-extenders were vitrified and stored for two days. Based on post-thaw motility duration and motility percentage assessments, two treatments with 10 μM and 0 μM of AFP had the highest and the lowest motility percentages respectively and they were objected to 1H NMR spectroscopy investigations in order to reveal the extremes of the metabolites dynamic range. Univariate (ANOVA) and multivariate (PCA) analysis of the resulting metabolic profiles indicated significant changes (P > 0.05) in metabolites. The level of some metabolites including acetate, adenine, creatine, creatine phosphate, lactate, betaine, sarcosine, β-alanine and trimethylamine N-oxide significantly decreased in vitrified semen while some others such as creatinine, guanidinoacetate, N, N-dimethylglycine, and glycine significantly increased. There were also significant differences between vitrified treatments in levels of creatine, creatine phosphate, creatinine, glucose, guanidinoacetate, lactate, N, N-dimethylglycine, and glycine, suggesting how fish AFP type III can be effective as a cryoprotectant. 相似文献
2.
Hien Thi Thu Nguyen Rikke Kristiansen Mette Vestergaard Reinhard Wimmer Per Halkj?r Nielsen 《Applied and environmental microbiology》2015,81(14):4809-4818
Dynamic anaerobic-aerobic feast-famine conditions are applied to wastewater treatment plants to select polyphosphate-accumulating organisms to carry out enhanced biological phosphorus removal. Acetate is a well-known substrate to stimulate this process, and here we show that different amino acids also are suitable substrates, with glycine as the most promising. 13C-labeled glycine and nuclear magnetic resonance (NMR) were applied to investigate uptake and potential storage products when activated sludge was fed with glycine under anaerobic conditions. Glycine was consumed by the biomass, and the majority was stored intracellularly as free glycine and fermentation products. Subsequently, in the aerobic phase without addition of external substrate, the stored glycine was consumed. The uptake of glycine and oxidation of intracellular metabolites took place along with a release and uptake of orthophosphate, respectively. Fluorescence in situ hybridization combined with microautoradiography using 3H-labeled glycine revealed uncultured actinobacterial Tetrasphaera as a dominant glycine consumer. Experiments with Tetrasphaera elongata as representative of uncultured Tetrasphaera showed that under anaerobic conditions it was able to take up labeled glycine and accumulate this and other labeled metabolites to an intracellular concentration of approximately 4 mM. All components were consumed under subsequent aerobic conditions. Intracellular accumulation of amino acids seems to be a novel storage strategy for polyphosphate-accumulating bacteria under dynamic anaerobic-aerobic feast-famine conditions. 相似文献
3.
Kun Liu Xin-Jian Ye Wen-Yi Hu Gui-Yan Zhang Guang-Hui Bai Liang-Cai Zhao Jia-Wei He Huan Zhu Jian-Bo Shao Zhi-Han Yan Hong-Chang Gao 《Molecular neurobiology》2013,48(3):729-736
The brain of a human neonate is more vulnerable to hypoglycemia than that of pediatric and adult patients. Repetitive and profound hypoglycemia during the neonatal period (RPHN) causes brain damage and leads to severe neurologic sequelae. Ex vivo high-resolution 1H nuclear magnetic resonance (NMR) spectroscopy was carried out in the present study to detect metabolite alterations in newborn and adolescent rats and investigate the effects of RPHN on their occipital cortex and hippocampus. Results showed that RPHN induces significant changes in a number of cerebral metabolites, and such changes are region-specific. Among the 16 metabolites detected by ex vivo 1H NMR, RPHN significantly increased the levels of creatine, glutamate, glutamine, γ-aminobutyric acid, and aspartate, as well as other metabolites, including succine, taurine, and myo-inositol, in the occipital cortex of neonatal rats compared with the control. By contrast, changes in these neurochemicals were not significant in the hippocampus of neonatal rats. When the rats had developed into adolescence, the changes above were maintained and the levels of other metabolites, including lactate, N-acetyl aspartate, alanine, choline, glycine, acetate, and ascorbate, increased in the occipital cortex. By contrast, most of these metabolites were reduced in the hippocampus. These metabolic changes suggest that complementary mechanisms exist between these two brain areas. RPHN appears to affect occipital cortex and hippocampal activities, neurotransmitter transition, energy metabolism, and other metabolic equilibria in newborn rats; these effects are further aggravated when the newborn rats develop into adolescence. Changes in the metabolism of neurotransmitter system may be an adaptive measure of the central nervous system in response to RPHN. 相似文献
4.
Glucose and glycine metabolism in regenerating tobacco protoplasts: followed nondestructively by nuclear magnetic resonance spectroscopy 总被引:8,自引:7,他引:1
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The metabolic states and the uptake and metabolism of [1-13C]glucose, [2-13C]glycine, and [15N]glycine in intact Nicotiana tabacum L. (cv Xanthi) mesophyll protoplasts were measured by 13C and 15N nuclear magnetic resonance spectroscopy. Changes in the concentration of metabolites during the first two days of culture in darkness were followed. Protoplasts isolated in 0.55 molar mannitol medium showed a drop in the concentration of all the intracellular metabolites during the first 28 hours of culture. Uptake of glucose and synthesis of glucose-derived metabolites were observed, indicating activity of glycolysis and the tricarboxylic acid cycle. Addition of glycine caused the accumulation of serine in dark cultured protoplasts, via the photorespiratory pathway. Glutamate dehydrogenase and glutamine synthetase activities in photorespiratory NH4+ assimilation were observed. Glucose uptake and metabolism and cell division were inhibited by 3 millimolar glycine, suggesting that the accumulating serine or the release of ammonia during serine synthesis had toxic effects in this system. 相似文献
5.
This study was designed to provide a database of the endogenous metabolites in earthworm extracts of the species, Eisenia veneta and Lumbricus terrestris by high resolution 1H-NMR spectroscopy in view of identifying biomarkers of toxicity or stress in environmental metabolomics studies. 1D and 2D NMR spectroscopic techniques enabled the identification and confirmation of the organic components in the tissue extracts of whole and segmented earthworms, dissected organs, and coelomic fluid. The extracts gave rise to characteristic 1H-NMR spectral fingerprints of the low MW metabolites contained, specific to the species of earthworm, and to the specific regions or dissected organs of the earthworms under investigation. Distinct changes in the normal biochemistry were observed upon starvation and cooling, such as markedly decreased glucose and maltose, but increased lactate, acetate, succinate, formate and acetone. Additionally, slightly decreased threonine, arginine, lysine, leucine, citrate, asparagine and glycine were observed. Furthermore, lactate could be identified as a biomarker of acute toxic stress in expressed coelomic fluid following exposure to a model ecotoxin (3-trifluoromethylaniline). This work supports the application of 1H-NMR spectroscopy for the study of changes in the normal invertebrate biochemistry in order to allow for the reliable assessment of biomarker responses following toxicity testing. 相似文献
6.
《Biochimica et Biophysica Acta (BBA)/General Subjects》2021,1865(11):129966
BackgroundPatients with pancreatic ductal adenocarcinoma (PDAC) have a very low survival rate and surgical resection is the only curative intent treatment available. However, the majority of patients relapse after surgery and identification of biomarkers for accurate prognostication of PDAC patients is required. We have recently identified a six biomarker (i.e., trigonelline, glycolate, hippurate, creatine, myoinositol and hydroxyacetone) urinary metabolite panel with very high potential to diagnose PDAC (Int J Cancer 2021;148:1508–18). This study aimed to assess the prognostic ability of these previously identified diagnostic metabolites in the urine of PDAC patients.MethodsMetabolite data from 88 PDAC patients was statistically assessed for their prognostic ability.ResultsA panel of three metabolites (i.e., trigonelline, hippurate and myoinositol) was able to stratify patients with good- or poor-prognosis based on overall survival. The PDAC patients with abnormal levels of 2 or more metabolites in their urine demonstrated significantly lower survival compared to patients with abnormal levels of one or less metabolites.ConclusionThese results demonstrate that the selected three metabolite panel could be used to stratify patients based on their prognostic outcomes and if independently validated may lead to the development of a urinary prognostic biomarker test for PDAC.General significanceThis study highlights the potential of using 1H-nuclear magnetic resonance spectroscopy for the identification of novel metabolites which can prognosticate cancer patients. 相似文献
7.
Chang‐Mo Kang Jin Seong Hyeon So Ra Kim Eun Kyeong Lee Hyun Jin Yun Sun Young Kim Young Kee Chae 《化学与生物多样性》2015,12(11):1696-1705
We employed the primary cell model system as a first step toward establishing a method to assess the influence of ionizing radiation by using a combination of common and abundant metabolites. We applied X‐ray irradiation amounts of 0, 1, and 5 Gy to the cells that were harvested 24, 48, or 72 h later, and profiled metabolites by 2D‐NMR spectroscopy to sort out candidate molecules that could be used to distinguish the samples under different irradiation conditions. We traced metabolites stemming from the input 13C‐glucose, identified twelve of them from the cell extracts, and applied statistical analysis to find out that all the metabolites, including glycine, alanine, and gluatamic acid, increased upon irradiation. The combinatorial use of the selected metabolites showed promising results where the product of signal intensities of alanine and lactate could differentiate samples according to the dose of X‐ray irradiation. We hope that this work can form a base for treating radiation‐poisoned patients in the future. 相似文献
8.
A.T. Peter P.W. Clark D.E. Van Roekel C.W. Luker J.D. Gaines W.T.K. Bosu 《Prostaglandins & other lipid mediators》1990,39(4)
A study was conducted to characterize the changes in the concentrations of three metabolites of prostanoids in the milk of a) heifers (n=14; control) inoculated with
(
) organisms into the udder and b) in heifers (n=10; treatment) vaccinated heifers. Milk samples were obtained from the challenged quarter and analyzed for the concentrations of stable metabolites of thromboxane A2 (TXB2), concentrations were significantly higher (P=0.03)bar compared to treated heifers. Milk PCM concentrations increased significantly (P=0.02) in control and treated heifers after the respective treatments, however, differences between the two groups were not significant. Milk PGEM concentrations also increased significantly (P=0.02) in control and treated heifers after the respective treatments, and there were no differences between the two groups. Results of the present study suggest that, the prostanoids have a role in the pathophysiologic process of coliform mastitis 相似文献
9.
Hong-Chang Gao Huan Zhu Cai-Yong Song Li Lin Yun Xiang Zhi-Han Yan Guang-Hui Bai Fa-Qing Ye Xiao-Kun Li 《Molecular neurobiology》2013,47(1):123-130
Parkinson’s disease (PD) is a neurodegenerative disorder characterized by the progressive loss of the dopaminergic neurons; however, its crucial mechanism of the metabolic changes of neurotransmitters remains ambiguous. The pathological mechanism of PD might involve cerebral metabolism perturbations. In this study, ex vivo proton nuclear magnetic resonance (1H NMR) was used to determine the level changes of 13 metabolites in the bilateral striatum of 6-hydroxydopamine (6-OHDA)-induced PD rats. The results showed that, in the right striatum of 6-OHDA-induced PD rats, increased levels of glutamate (Glu) and γ-aminobutyric acid (GABA) concomitantly with decreased level of glutamine (Gln) were observed compared to the control. Whereas, in the left striatum of 6-OHDA-induced PD rats, increased level of Glu with decreased level of GABA and unchanged Gln were observed. Other cerebral metabolites including lactate, alanine, creatine, succinate, taurine, and glycine were also found to have some perturbations. The observed metabolic changes for Glu, Gln, and GABA are mostly likely the result of a shift in the steady-state equilibrium of the Gln-Glu-GABA metabolic cycle between astrocytes and neurons. The altered Gln and GABA levels are most likely as a strategy to protect neurons from Glu excitotoxic injury after striatal dopamine depletion. Changes in energy metabolism and tricarboxylic acid cycle might be involved in the pathogenesis of PD. 相似文献
10.
1. The effect of triperidol on the metabolism of glucose, pyruvate, glutamate, aspartate and glycine was studied with rat brain-cortex slices, U-14C-labelled substrates and a quantitative radiochromatographic technique. 2. Triperidol at a concentration of 0·2mm decreased the oxygen uptake and the 14CO2 production by about 30% when glucose, pyruvate and glutamate were used as substrates, whereas no effects were observed with aspartate and glycine. 3. The drug did not alter qualitatively the metabolic pattern of the substrates. 4. Quantitatively, triperidol decreased the incorporation of 14C from [U-14C]glucose and [U14-C]-pyruvate into glutamate, glutamine and γ-aminobutyrate but not into lactate, alanine and aspartate. The overall utilization rates of glucose and pyruvate were decreased. The relative specific radioactivities of glutamate and aspartate were also decreased. 5. Triperidol increased the rate of disappearance of U-14C-labelled glutamate, aspartate and glycine from the incubation medium, and altered the distribution of their metabolites between medium and tissue. 6. No appreciable effect of triperidol on [1-14C]galactose disappearance was found. 相似文献
11.
Influence of pH on Terminal Carbon Metabolism in Anoxic Sediments from a Mildly Acidic Lake 总被引:7,自引:5,他引:2
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The carbon and electron flow pathways and the bacterial populations responsible for transformation of H2-CO2, formate, methanol, methylamine, acetate, glycine, ethanol, and lactate were examined in sediments collected from Knaack Lake, Wis. The sediments were 60% organic matter (pH 6.2) and did not display detectable sulfate-reducing activity, but they contained the following average concentration (in micromoles per liter of sediment) of metabolites and end products: sulfide, 10; methane, 1,540; CO2, 3,950; formate, 25; acetate, 157; ethanol, 174; and lactate, 138. Methane was produced predominately from acetate, and only 4% of the total CH4 was derived from CO2. Methanogenesis was limited by low environmental temperature and sulfide levels and more importantly by low pH. Increasing in vitro pH to neutral values enhanced total methane production rates and the percentage of CO2 transformed to methane but did not alter the amount of 14CO2 produced from [2-14C]acetate (~24%). Analysis of both carbon transformation parameters with 14C-labeled tracers and bacterial trophic group enumerations indicated that methanogenesis from acetate and both heterolactic- and acetic acid-producing fermentations were important to the anaerobic digestion process. 相似文献
12.
Shoot tips of M.4 apple clone were excised from actively growing one year-old stoolbed branches, and cultured in order to determine the optimal nutrient medium for each stage of their in vitro culture. The basal medium (BM) used was that described by Murashige and Skoog, supplemented with vitamins, glycine, myoinositol, sucrose, with or without agar, and different combinations of plant growth regulators. Best media for each stage were: BM+0.5 mg 1-1 indole-3yl-butyric acid (IBA)+0.5 mg 1-1 6-benzylaminopurine (BAP) for explant establishment (Stage I); BM+0.1 mg 1-1 IBA+1.0 mg 1-1 BAP for multiplication and internode enlargement (Stage II); and 2.0 mg 1-1 IBA+0.1 mg 1-1 BAP without agar for the rooting of the plantlets (Stage III). 相似文献
13.
J. Ampofo‐Asiama V. M. M. Baiye M. L. A. T. M. Hertog E. Waelkens A. H. Geeraerd B. M. Nicolai 《Plant biology (Stuttgart, Germany)》2014,16(3):594-606
The storage of fruits and vegetables under a controlled atmosphere can induce low oxygen stress, which can lead to post‐harvest losses through the induction of disorders such as core breakdown and browning. To gain better understanding of the metabolic response of plant organs to low oxygen, cultured tomato cells (Lycopersicum esculentum) were used as a model system to study the metabolic stress response to low oxygen (0 and 1 kPa O2). By adding 13C labelled glucose, changes in the levels of polar metabolites and their 13C label accumulation were quantified. Low oxygen stress altered the metabolite profile of tomato cells, with the accumulation of the intermediates of glycolysis in addition to increases in lactate and sugar alcohols. 13C label data showed reduced label accumulation in almost all metabolites except lactate and some sugar alcohols. The results showed that low oxygen stress in tomato cell culture activated fermentative metabolism and sugar alcohol synthesis while inhibiting the activity of the TCA cycle and the biosynthesis of metabolites whose precursors are derived from central metabolism, including fluxes to most organic acids, amino acids and sugars. 相似文献
14.
Peng?Zheng Hong-Chang?Gao Zhi-Guo?Qi Jian-Min?Jia Fang?Fang?Li Jian?Jun?Chen Ying?Wang Jing?Guo N.?D.?Melgiri Peng?Xie
Suicide is the most serious consequence of major depressive disorder (MDD), yet a vast majority of MDD patients never attempt nor commit suicide. This discrepancy suggests a predisposition to suicidal behavior independent of MDD. However, the molecular basis of this predisposition remains largely unknown, hampering development of specific and targeted treatment of MDD patients at risk for suicide. A proton nuclear magnetic resonance (1H NMR)-based metabonomic approach was used to capture metabolic perturbations related to suicide predisposition in the context of MDD. 1H NMR spectra of plasma sampled from drug-naïve depressed suicide attempters (n = 21), non-attempters (n = 35), and healthy controls (n = 35) were recorded and analyzed through a multivariate statistical approach. Multivariate statistical analysis demonstrated that the depressed suicide attempter group was significantly distinguishable from the depressed non-attempter group and controls group. Several key metabolites, including lipids (low-density lipoprotein, very low-density lipoprotein, cholesterol and unsaturated lipid), lipid metabolism-related molecules (glucose, pyruvate and lactate) and amino acids (alanine, glycine and taurine) responsible for discriminating depressed suicide attempters from the nonattempters and controls were identified. This study is the first to indicate that peripheral perturbations in lipid and amino acid metabolism may be implicated in the predisposition to suicide in MDD patients. 相似文献
15.
Prediabetes has been associated with alterations in male reproductive tract, especially in testis and epididymis. Moreover, in vitro studies described a promising action of tea (Camellia sinensis L.) against metabolic dysfunctions. Herein, we hypothesized that white tea (WTEA) ingestion by prediabetic animals could ameliorate the metabolic alterations induced by the disease in testicular and epididymal tissues, preserving sperm quality. WTEA infusion was prepared and its phytochemical profile was evaluated by 1H-NMR. A streptozotocin-induced prediabetic rat model was developed and three experimental groups were defined: control, prediabetic (PreDM) and prediabetic drinking WTEA (PreDM+WTEA). Metabolic profiles of testis and epididymis were evaluated by determining the metabolites content (1H-NMR), protein levels (western blot) and enzymatic activities of key metabolic intervenient. The quality of spermatozoa from cauda epididymis was also assessed. Prediabetes increased glucose transporter 3 protein levels and decreased lactate dehydrogenase activity in testis, resulting in a lower lactate content. WTEA ingestion led to a metabolic adaptation to restore testicular lactate content. Concerning epididymis, prediabetes decreased the protein levels of several metabolic intervenient, resulting in decreased lactate and alanine content. WTEA consumption restored most of the evidenced alterations, however, not lactate content. WTEA also improved epididymal sperm motility and restored sperm viability. Prediabetes strongly affected testicular and epididymal metabolic status and most of these alterations were restored by WTEA consumption, resulting in the improvement of sperm quality. Our results suggest that WTEA consumption can be a cost-effective strategy to improve prediabetes-induced reproductive dysfunction. 相似文献
16.
Qishun Zhou Sinem Usluer Fangrong Zhang Aneta J. Lenard Benjamin M. R. Bourgeois Tobias Madl 《Protein science : a publication of the Protein Society》2021,30(7):1438
Intrinsically disordered proteins and proteins containing intrinsically disordered regions are highly abundant in the proteome of eukaryotes and are extensively involved in essential biological functions. More recently, their role in the organization of biomolecular condensates has become evident and along with their misregulation in several neurologic disorders. Currently, most studies involving these proteins are carried out in vitro and using purified proteins. Given that in cells, condensate‐forming proteins are exposed to high, millimolar concentrations of cellular metabolites, we aimed to reveal the interactions of cellular metabolites and a representative condensate‐forming protein. Here, using the arginine–glycine/arginine–glycine–glycine (RG/RGG)‐rich cold inducible RNA binding protein (CIRBP) as paradigm, we studied binding of the cellular metabolome to CIRBP. We found that most of the highly abundant cellular metabolites, except nucleotides, do not directly bind to CIRBP. ATP, ADP, and AMP as well as NAD+, NADH, NADP+, and NADPH directly interact with CIRBP, involving both the folded RNA‐recognition motif and the disordered RG/RGG region. ATP binding inhibited RNA‐driven phase separation of CIRBP. Thus, it might be beneficial to include cellular metabolites in in vitro liquid–liquid phase separation studies of RG/RGG and other condensate‐forming proteins in order to better mimic the cellular environment in the future. 相似文献
17.
R.F. Cooke N. DiLorenzo A. DiCostanzo J.V. Yelich J.D. Arthington 《Animal Feed Science and Technology》2009,150(3-4):163-174
Two experiments were conducted to evaluate a commercially available supplemental N source for beef cattle (Fermenten®; Church & Dwight Co., Inc., Princeton, NJ, USA). The first experiment evaluated kinetics of in vitro NH3-N release using batch cultures of rumen fluid incubated with: control (no N added), soybean meal, urea, and Fermenten®. Ammonia-N was measured at 0, 0.5, 2, 4, 6, 8, 12 and 24 h after incubation began. A treatment by time interaction (P<0.01) occurred in which, during the initial 2 h, Fermenten® cultures had the highest (P<0.01) NH3-N but, from 4 to 24 h, the highest (P<0.01) NH3-N concentrations were with urea-incubated cultures. The total increase in NH3-N concentrations from 0 to 24 h of incubation was less for Fermenten® (P<0.01) than for the soybean meal and urea. The second experiment assessed effects of Fermenten® supplementation on growth, blood parameters, voluntary forage intake and reproductive performance of beef heifers. Sixty heifers, stratified by initial body weight (BW), were randomly allocated to one of two treatments that consisted of iso-nitrogenous grain-based supplements containing either Fermenten® (72 g/kg, as-fed) or urea (9.7 g/kg, as-fed). Supplements were offered three times weekly at a rate of 2.4 kg of dry matter per heifer daily. Shrunk BW was measured on days 0 and 112 for calculation of daily body weight gain. Body volume measurements were completed on days 0, 28, 56, 84 and 112, whereas pelvic area was assessed on days 0, 56 and 112. Blood samples were collected on days 28, 56, 84 and 112 for analysis of metabolites and hormones. On day 56, 2 heifers, which were randomly selected from each pasture, were placed in individual feeding stations for 26 days to determine treatment effects on voluntary forage intake. On day 112, all heifers were grouped by treatment and exposed to bulls for 60 days. Fewer heifers offered the Fermenten® supplement attained puberty (P<0.05) and became pregnant during the study compared to heifers fed urea (0.60 and 0.93, respectively; P<0.01). Addition of Fermenten® to batch cultures of rumen fluid rapidly increased NH3-N concentrations, whereas further increases occurred in a slower and steady rate. Beef heifers fed a supplement containing Fermenten® had similar growth and development, but inferior reproductive performance, than heifers fed a supplement containing urea. 相似文献
18.
In the present study, in vitro regeneration system for a recalcitrant woody tree legume, Leucaena leucocephala (cvs. K-8, K-29, K-68 and K-850) from mature tree derived nodal explants as well as seedling derived cotyledonary node explants
was developed. Best shoot initiation and elongation was found on full-strength Murashige and Skoog (MS) medium supplemented
with 3 % (m/v) sucrose, 100 mg dm−3 myoinositol, 100 mg dm−3 glutamine, 20.9 μM N
6-benzylamino-purine (BAP) and 5.37 μM 1-naphthalene acetic acid (NAA). Rooting was induced in half-strength MS medium containing
2 % (m/v) sucrose, 100 mg dm−3 myoinositol, 14.76 μM indole-3-butyric acid (IBA) and 0.23 μM kinetin. The cultivar K-29 gave the best response under in vitro conditions. Rooted plantlets were subjected to hardening and successfully transferred to greenhouse. Further, somatic embryogenesis
from nodal explants of cv. K-29 via an intermittent callus phase was also established. Pronounced callusing was observed on full-strength MS medium containing
3 % (m/v) sucrose, 100 mg dm−3 myoinositol, 40.28 μM NAA and 12.24 μM BAP. These calli were transferred to induction medium and maximum number of globular
shaped somatic embryos was achieved in full-strength MS medium fortified with 3 % (m/v) sucrose, 100 mg dm−3 myoinositol, 15.0 μM 2,4-dichlorophenoxyacetic acid (2,4-D), 5.0 μM BAP and 1.0 mM proline. Moreover, an increase in endogenous
proline content up to 28th day of culture in induction medium was observed. These globular shaped somatic embryos matured in full-strength MS medium
with 3 % (m/v) sucrose, 100 mg dm−3 myoinositol, 10.0 μM BAP, 2.5 to 5.0 μM IBA and 0.5 mM spermidine. 相似文献
19.
G. Roy 《The Journal of membrane biology》1995,147(1):35-44
During volume regulation in hypotonic media, glial cells release a large portion of their amino acids. These amino acid losses appear to be mediated by a diffusion type of transport and a swelling-activated chloride channel seems to be involved. The objective of this project was to provide direct evidence that amino acids could diffuse through a Cl? channel. Using a human glial cell line, Cl? currents activated in hypotonic media were measured in whole-cell patch clamp. To measure the currents produced by amino acids, it was necessary to increase the pH of external solutions to basic values reaching 9.6 and 10.0 to raise the concentration of the anionic form of these amino acids. Introducing external hypotonic media containing high concentrations of amino acids, like glycine, taurine, glutamine and glutamate, it was possible to measure their respective current-voltage curves with NMDG-Cl-filled pipettes. From the reversal potentials, their permeability ratios with respect to chloride were determined. It was found that the low molecular weight amino acids, like glycine, were most permeant, while the larger ones, like glutamine, had a lower permeability with respect to chloride. The amino acids with two carboxyl groups, like glutamate, had a much lower permeability ratio. The reversal potentials for some metabolites, like lactate and malate were also measured for comparison. These results demonstrate that amino acids can diffuse through anion channels and that activation of these channels in pathological conditions could be at least partly responsible for the observed increase in external amino acids. 相似文献
20.
Staphylococcus aureus is a major pathogen in the medical area and food-producing sector. Detailed analyses of its basic cell physiology will help comprehensively understand this pathogen, which will be useful for developing novel diagnostic and treatment tools. Oxygen is one of the most crucial growth-limiting factors for S. aureus. In this study, to characterize and distinguish metabolic profiles of S. aureus cultivated under aerobic and anaerobic conditions, nontargeted analyses of both types of cultures were carried out using (1)H nuclear magnetic resonance spectroscopy. Fifty compounds were identified by Chenomx software. Characteristics of metabolic profiles were achieved by using principal components analysis. During aerobic growth, S. aureus mainly consumed glucose, alanine, arginine, glycine, isoleucine, leucine, phenylalanine, and acetate. Meanwhile, it accumulated 17 metabolites, mainly 2-oxoglutarate, isobutyrate, isovalerate, succinate, and ethanol. Under anaerobic condition, S. aureus mainly consumed glucose, arginine, and threonine. Meanwhile, it accumulated 13 metabolites, mainly ethanol, lactate, and ornithine. The representative metabolites that could most significantly differentiate metabolic profiles of S. aureus were isobutyrate, isovalerate, and succinate in aerobic cultivation; and lactate, ethanol, and ornithine in anaerobic cultivation. Among these metabolites, isobutyrate and ornithine were present only in aerobic and anaerobic culture, respectively. 相似文献