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1.
Nat Prod Res ; 38(10): 1687-1694, 2024 May.
Article in English | MEDLINE | ID: mdl-37234037

ABSTRACT

Bioassay-guided isolation of the stems of Garcinia paucinervis led to one new adamantane-type polycyclic polyprenylated acylphloroglucinols (PPAPs), (-)-garpauvinin A (1), and four known analogues (2-5). The structure and absolute configuration of 1 was established via spectroscopic techniques and ECD method. All the isolates displayed moderate antiproliferative activity against HL-60, PC-3 and Caco-2 human cancer cell lines with IC50 values ranging from 0.81 to 19.92 µM, and exhibited low toxicity on WPMY-1 normal human cells, showing selectivity between normal and malignant prostate cells. The biosynthetic pathways of the isolated PPAPs were proposed.


Subject(s)
Garcinia , Hypericum , Humans , Molecular Structure , Caco-2 Cells , Garcinia/chemistry , HL-60 Cells , Phloroglucinol , Hypericum/chemistry
2.
Org Biomol Chem ; 20(43): 8528-8532, 2022 Nov 09.
Article in English | MEDLINE | ID: mdl-36278495

ABSTRACT

Two pairs of unprecedented ß-carboline-phenylpropanoid heterogeneous alkaloids, (±)-pheharmines A-B (1-4), characterized by a morpholino[4,3,2-hi]ß-carboline core with two chiral centers, were isolated from the roots of Peganum harmala. The structures, including their absolute configurations, were identified using spectroscopic analyses and electronic circular dichroism (ECD) calculations. The biosynthetic hypothesis for the formation of pheharmines A-B was proposed. Compounds 1-4 exhibited moderate cytotoxic activities against HL-60 cell lines.


Subject(s)
Alkaloids , Peganum , Humans , Peganum/chemistry , Peganum/metabolism , Morpholinos/analysis , Morpholinos/metabolism , Seeds , Molecular Structure , Alkaloids/pharmacology , Alkaloids/chemistry , Carbolines/pharmacology , Carbolines/chemistry
3.
Zhongguo Zhong Yao Za Zhi ; 47(10): 2676-2680, 2022 May.
Article in Chinese | MEDLINE | ID: mdl-35718486

ABSTRACT

The chemical constituents from the roots of Thalictrum cultratum and T. baicalense were investigated. By various isolation methods, such as silica gel, aluminium oxide, ODS, and Sephadex LH-20 column chromatographies, and semi-preparative HPLC, 11 simple isoquinoline alkaloids were isolated from the ethanol extract of the roots of these two plants, including a new compound, named dehydrothalflavine(1), and ten known ones(2-11): N-methylcorydaline(2), N-methylthalidaldine(3), thaliflavine(4), oxyhydrastinine(5), noroxyhydrastinine(6), dimethoxyisoquinolone(7), thalactamine(8), dehydronoroxyhydrastinine(9), 6,7-dimethoxy-2-methyl-1,2,3,4-tetrahydroisoquinoline(10), and isopicnarrhine(11). Their structures were elucidated on the basis of HR-ESI-MS and 1 D and 2 D NMR techniques. Compound 1 was a new isoquinoline alkaloid. Compound 11 was obtained from Tha-lictrum plant for the first time. All compounds did not show cytotoxic activities against HL-60, U937, HCT116, Caco-2, and HepG2 cancer cell lines.


Subject(s)
Alkaloids , Thalictrum , Alkaloids/analysis , Caco-2 Cells , Humans , Isoquinolines/pharmacology , Plant Roots/chemistry , Thalictrum/chemistry
4.
J Asian Nat Prod Res ; 23(11): 1043-1050, 2021 Nov.
Article in English | MEDLINE | ID: mdl-34709085

ABSTRACT

Two new prenylated coumarins, 3'-hydroxytoddanone (1), and isotoddalolactone (2), along with four known analogues (3-6) were isolated from the roots of Zanthoxylum nitidum. Their chemical structures were elucidated based on extensive spectroscopic interpretation and HR-ESI-MS analysis. The absolute configuration of compound 2 was determined by comparing experimental ECD spectrum with that calculated by the time-dependent density functional theory (TDDFT) method. Compounds 4-6 were isolated from the Zanthoxylum genus for the first time. The two new compounds were tested for antiproliferative activities in vitro on the HL-60, K562 and THP-1 cell lines. Compounds 1 and 2 exhibited moderate cell growth inhibitory activities in vitro against human leukemic HL-60 cell lines, with IC50 values of 32.64 and 33.15 µM, respectively.


Subject(s)
Zanthoxylum , Coumarins/pharmacology , Molecular Structure , Plant Roots
5.
Org Lett ; 22(19): 7522-7525, 2020 10 02.
Article in English | MEDLINE | ID: mdl-32936652

ABSTRACT

Two nonbiaryl axially chiral ß-carboline-quinazoline dimers, pegaharmols A (1) and B (2), were isolated from the roots of Peganum harmala. Their planar structures were elucidated by the spectroscopic methods of high-resolution mass spectrometry and 1D and 2D nuclear magnetic resonance (NMR). The stereochemistry was established by a comparison between the experimental data of NMR and electronic circular dichroism and the computed data by quantum mechanical calculations. It is discovered for the first time that the ß-carboline at the C-8 position is bonded to the vasicine at the C-9 position. 1 exhibited moderate cytotoxic activity against HL-60 and A549 cell lines.


Subject(s)
Alkaloids/chemistry , Antineoplastic Agents, Phytogenic/pharmacology , Carbolines/pharmacology , Peganum/chemistry , Plant Roots/chemistry , Quinazolines/chemistry , Antineoplastic Agents, Phytogenic/chemistry , Antineoplastic Agents, Phytogenic/isolation & purification , Carbolines/chemistry , Carbolines/isolation & purification , Drug Screening Assays, Antitumor , HL-60 Cells , Humans , Molecular Structure , Plant Extracts/chemistry
6.
Org Lett ; 22(19): 7439-7442, 2020 10 02.
Article in English | MEDLINE | ID: mdl-32886519

ABSTRACT

Baicalensines A (1) and B (2) were isolated from the roots of Thalictrum baicalense and structurally characterized using spectroscopic data, 13C NMR calculations, and the CASE algorithm. Compound 1, representing a new class of alkaloid dimers, contains berberine conjugated to a ring-opened isoquinoline. Compound 2 is the first reported natural benzylisoquinoline bearing a formyl group at C-3. Plausible biosynthetic pathways are proposed. Compound 1 exerted moderate cytotoxicity against the Caco-2 and HL-60 cell lines.


Subject(s)
Antineoplastic Agents, Phytogenic/pharmacology , Berberine/pharmacology , Thalictrum/chemistry , Alkaloids/chemistry , Alkaloids/isolation & purification , Alkaloids/pharmacology , Antineoplastic Agents, Phytogenic/chemistry , Antineoplastic Agents, Phytogenic/isolation & purification , Berberine/chemistry , Berberine/isolation & purification , Caco-2 Cells , HL-60 Cells , Humans , Isoquinolines/chemistry , Isoquinolines/isolation & purification , Isoquinolines/pharmacology , Molecular Structure , Plant Roots/chemistry
7.
Sci Rep ; 10(1): 1815, 2020 02 04.
Article in English | MEDLINE | ID: mdl-32020007

ABSTRACT

The purpose of this study was to compare differences of energy expenditure and substrate metabolism between motorized-treadmill and overground running in three different velocities in Chinese middle-aged women. In total, 74 healthy middle-aged women (age, 48 ± 4 years; height, 159.4 ± 4.9 cm; weight, 58.6 ± 6.7 kg; and body-mass index (BMI), 23.1 ± 2.7 kg/m2) volunteered to participate in this study. Bioelectrical-impedance analysis was used to measure body composition. Energy expenditure, carbohydrates (CHO), and fat oxidation were calculated with indirect calorimetry during motorized-treadmill and overground running. Running speed from slow to fast was 7.0, 8.0, and 9.0 km/h. The duration of each velocity was 6 min, separated by 5-15 min rest. There was no significant difference in energy expenditure between overground and treadmill running at the speed of 7 km/h (8.10 ± 1.25 vs. 7.75 ± 1.13 kcal/min, p > 0.05). Energy expenditure of overground running at 8 and 9 km/h was higher than that of treadmill running (9.36 ± 1.40 vs. 8.54 ± 1.21 kcal/min; 10.33 ± 1.55 vs. 9.54 ± 1.36 kcal/min; both p < 0.01). Fat contribution to energy consumption was significantly higher during treadmill running than during overground running (both p < 0.01) at speeds of 8 and 9 km/h. Overground running at high intensity incurred greater energy consumption than treadmill running did. However, results showed greater fat utilization during treadmill running than during overground running at high intensity. It is critical that these differences are taken into account when we prescribe training modes and intensities for middle-aged women.


Subject(s)
Body Composition/physiology , Energy Metabolism/physiology , Running/physiology , Adult , China , Electric Impedance , Exercise Test , Female , Humans , Middle Aged , Oxygen Consumption/physiology
8.
Fitoterapia ; 139: 104359, 2019 Nov.
Article in English | MEDLINE | ID: mdl-31629049

ABSTRACT

Two new lignanamides, majusamides A and B (1 and 2), and two new alkaloids, chelidoniumine (3) and tetrahydrocoptisine N-oxide (4), together with six known hydroxycinnamic acid amides (HCCA) were isolated from the 75% ethanol extract of Chelidonium majus through the silica gel, Sephadex LH-20, MCI, ODS column chromatography, and semi-HPLC. Their structures were determined on the basis of spectroscopic data and physico-chemical methods. The absolute configurations of 1-3 were determined by electronic circular dichroism (ECD) calculations. The anti-inflammatory activities of all the isolates on the NO production in lipopolysaccharide (LPS)-induced macrophages were evaluated. Compounds 7 and 9 exhibited moderate inhibitory activity with IC50 values of 25.3 ±â€¯0.5 and 23.5 ±â€¯1.7 µM, respectively.


Subject(s)
Alkaloids/pharmacology , Amides/pharmacology , Anti-Inflammatory Agents/pharmacology , Chelidonium/chemistry , Lignans/pharmacology , Nitric Oxide/metabolism , Alkaloids/isolation & purification , Amides/isolation & purification , Animals , Anti-Inflammatory Agents/isolation & purification , Cell Line , China , Lignans/isolation & purification , Mice , Microglia/drug effects , Molecular Structure , Phytochemicals/isolation & purification , Phytochemicals/pharmacology , Plant Components, Aerial/chemistry
9.
Fitoterapia ; 130: 37-42, 2018 Oct.
Article in English | MEDLINE | ID: mdl-30086333

ABSTRACT

Three new (1a/1b and 2b) and five known flavans (2a, 6a/6b, 7, and 8), one new flavan glycoside (3), and two new (4 and 5) and six known 1,3-diphenylpropanes (9-14) were isolated from the twigs of Broussonetia kazinoki. Compounds 1, 2, and 6 are scalemic mixtures, and were resolved by chiral HPLC to provide 1a/1b, 2a/2b, and 6a/6b. The structures of these compounds were elucidated by extensive spectroscopic methods, including NMR, MS, and ECD analyses. Compounds 1, 2, 5, 8, 9, 11, and 12 showed in vitro inhibition of protein tyrosine phosphatase 1B (PTP1B).


Subject(s)
Broussonetia/chemistry , Flavonoids/isolation & purification , Glycosides/isolation & purification , Phytochemicals/isolation & purification , Protein Tyrosine Phosphatase, Non-Receptor Type 1/antagonists & inhibitors , China , Flavonoids/pharmacology , Glycosides/pharmacology , Molecular Structure , Phytochemicals/pharmacology , Structure-Activity Relationship
10.
Am J Ther ; 25(6): e642-e651, 2018.
Article in English | MEDLINE | ID: mdl-29557807

ABSTRACT

BACKGROUND: Diabetes mellitus, metabolic syndrome, and other obesity-related diseases are characterized by insulin resistance (IR) as a common pathophysiological change and are closely related to cardiovascular disease, which seriously threaten human health. Telmisartan belongs to a group of drugs called angiotensin II receptor antagonists (ARBs) and it can partially activate peroxisome proliferator-activated receptors. Animal experiments have confirmed that telmisartan can regulate glucose and lipid metabolism, and improve IR. STUDY QUESTION: This study performs a systematic review of the advantages of telmisartan in improving IR and compared it with other ARBs. STUDY DESIGN: Randomized controlled trials (RCTs) that compared telmisartan with other ARBs in patients with obesity, diabetes, impaired glucose tolerance, and metabolic syndrome were searched from PubMed, EMBASE, the Cochrane Library, China National Knowledge Infrastructure, Wan Fang Database, and Chinese biomedical literature database (CBM). RCTs published as of the end of April 2017 were included in the present study. MEASURES AND OUTCOMES: The outcomes included homeostasis model assessment of insulin resistance, fasting blood glucose level, fasting insulin level, diastolic blood pressure, and systolic blood pressure. We used a fixed-effects model or random-effects model to pool the estimates according to the heterogeneity between the included studies. RESULTS: A total of 21 RCTs, which included 1679 patients, were included. Results revealed that telmisartan was superior in improving homeostasis model assessment of insulin resistance (mean difference = -0.23, 95% confidence interval [CI], -0.40 to -0.06), reducing fasting blood glucose level (mean difference = -0.32, 95% CI, -0.57 to -0.07), reducing fasting insulin level (mean difference = -1.01, 95% CI, -1.63 to -0.39), and decreasing diastolic blood pressure (mean difference = -1.46, 95% CI, -2.10 to -0.82) compared with other ARBs. However, for the decrease in systolic pressure, the difference was not statistically significant (mean difference = -0.73, 95% CI, -1.53 to 0.07). CONCLUSION: Telmisartan can better improve IR compared with other ARBs.


Subject(s)
Angiotensin II Type 1 Receptor Blockers/therapeutic use , Diabetes Mellitus/drug therapy , Hypertension/drug therapy , Insulin Resistance , Metabolic Syndrome/metabolism , Telmisartan/therapeutic use , Blood Glucose/drug effects , Blood Pressure/drug effects , Diabetes Mellitus/blood , Diabetes Mellitus/metabolism , Fasting , Humans , Hypertension/metabolism , Insulin/pharmacology , Insulin/therapeutic use , Metabolic Syndrome/blood , Randomized Controlled Trials as Topic , Telmisartan/pharmacology , Treatment Outcome
11.
J Nanosci Nanotechnol ; 18(6): 4087-4092, 2018 Jun 01.
Article in English | MEDLINE | ID: mdl-29442747

ABSTRACT

T-Ag/ZnO nanoflowers were successfully fabricated via two steps methods on zinc foil. The chemical composition of norfloxacin was investigated by FTIR spectroscopy. The morphology, composition, and structural and optical properties of the as-synthesized materials were characterized. The results show that triangular silver nanoplates exhibit unique surface plasmon resonance (SPR) absorption spectra, and the absorption spectrum range of ZnO nanoflowers are effectively expanded by coating triangular silver nanoplates. The photocatalytic degradation of norfloxacin activity can be obviously improved because of a synergetic effect and unique SPR of triangular silver nanoplates in the T-Ag/ZnO nanoflowers under visible light. In addition, the possible mechanism for T-Ag/ZnO nanoflowers for the photodegradation of norfloxacin are discussed. The stability of T-Ag/ZnO nanoflowers are also studied.

12.
Fitoterapia ; 127: 220-225, 2018 Jun.
Article in English | MEDLINE | ID: mdl-29474978

ABSTRACT

Bioassay-guided fractionation of the dichloromethane-soluble portion of the stems of Garcinia paucinervis led to the isolation of eight new xanthones, including three pairs of enantiomers, (+) and (-) paucinervins L-N (1a-3a, and 1b-3b), one optically pure compound, (-) paucinervin O (4), and one new analogue, paucinervin P (5), as well as thirteen known xanthones (6-18). Their structures were established by detailed analysis of extensive spectroscopic data. The absolute configurations of 1-4 were confirmed by ECD calculations. All the isolates 1-18 displayed antiproliferative effect against HL-60 with IC50 values ranging from 0.87 to 29.14 µM, of which compound 5 was the most active. Compounds 6, and 14 exhibited potential inhibitory activity against PC-3 cells, while compounds 5-7, 14, and 16-17 displayed cytotoxic potency against Caco-2 cells. A preliminary structure-activity relationship was also discussed.


Subject(s)
Antineoplastic Agents, Phytogenic/chemistry , Garcinia/chemistry , Xanthones/chemistry , Caco-2 Cells , HL-60 Cells , Humans , Molecular Structure , Plant Stems/chemistry , Structure-Activity Relationship
13.
Chem Biodivers ; 14(6)2017 Jun.
Article in English | MEDLINE | ID: mdl-28371315

ABSTRACT

Three new alkylated chalcones, villosins A - C (1 - 3), five known analogues, together with ten known coumarins, were isolated from Fatoua villosa. The structures of the new compounds were elucidated by extensive spectroscopic analysis, including 1D-, 2D-NMR, and MS data. Compounds 1 - 3 showed cytotoxicity against five kinds of human tumor cell lines (NB4, A549, SHSY5Y, PC3, and MCF7) with IC50 values ranging from 1.4 ± 0.1 to 5.7 ± 0.3 µm.


Subject(s)
Antineoplastic Agents, Phytogenic/chemistry , Chalcones/isolation & purification , Coumarins/isolation & purification , Digitaria/chemistry , Alkylation , Antineoplastic Agents, Phytogenic/isolation & purification , Antineoplastic Agents, Phytogenic/pharmacology , Cell Line, Tumor , Chalcones/chemistry , Chalcones/pharmacology , Coumarins/pharmacology , Humans , Inhibitory Concentration 50 , Molecular Structure , Spectrum Analysis
14.
Neurorehabil Neural Repair ; 29(8): 767-76, 2015 Sep.
Article in English | MEDLINE | ID: mdl-25549656

ABSTRACT

BACKGROUND: Augmented physical training with assistance from robot and neuromuscular electrical stimulation (NMES) may introduce intensive motor improvement in chronic stroke. OBJECTIVE: To compare the rehabilitation effectiveness achieved by NMES robot-assisted wrist training and that by robot-assisted training. METHODS: This study was a single-blinded randomized controlled trial with a 3-month follow-up. Twenty-six hemiplegic subjects with chronic stroke were randomly assigned to receive 20-session wrist training with an electromyography (EMG)-driven NMES robot (NMES robot group, n = 11) and with an EMG-driven robot (robot group, n = 15), completed within 7 consecutive weeks. Clinical scores, Fugl-Meyer Assessment (FMA), Modified Ashworth Score (MAS), and Action Research Arm Test (ARAT) were used to evaluate the training effects before and after the training, as well as 3 months later. An EMG parameter, muscle co-contraction index, was also applied to investigate the session-by-session variation in muscular coordination patterns during the training. RESULTS: The improvement in FMA (shoulder/elbow, wrist/hand) obtained in the NMES robot group was more significant than the robot group (P < .05). Significant improvement in ARAT was achieved in the NMES robot group (P < .05) but absent in the robot group. NMES robot-assisted training showed better performance in releasing muscle co-contraction than the robot-assisted across the training sessions (P < .05). CONCLUSIONS: The NMES robot-assisted wrist training was more effective than the pure robot. The additional NMES application in the treatment could bring more improvements in the distal motor functions and faster rehabilitation progress.


Subject(s)
Electric Stimulation Therapy/methods , Electromyography/methods , Robotics/instrumentation , Stroke Rehabilitation , Wrist/physiopathology , Brain Ischemia/complications , Brain Ischemia/physiopathology , Brain Ischemia/rehabilitation , Cerebral Hemorrhage/complications , Cerebral Hemorrhage/physiopathology , Cerebral Hemorrhage/rehabilitation , Chronic Disease , Elbow/physiopathology , Electric Stimulation Therapy/instrumentation , Electromyography/instrumentation , Female , Follow-Up Studies , Hand/physiopathology , Humans , Male , Middle Aged , Movement Disorders/etiology , Movement Disorders/physiopathology , Movement Disorders/rehabilitation , Muscle Contraction/physiology , Recovery of Function/physiology , Severity of Illness Index , Shoulder/physiopathology , Single-Blind Method , Stroke/complications , Stroke/physiopathology , Treatment Outcome
15.
Zhonghua Yi Xue Za Zhi ; 93(23): 1801-5, 2013 Jun 18.
Article in Chinese | MEDLINE | ID: mdl-24124713

ABSTRACT

OBJECTIVE: To explore the swallowing functions of stroke patients with dysphagia. METHODS: A total of 41 subjects were recruited.There were 15 stroke patients with dysphagia, 12 stroke patients without swallowing disorders and 14 age-and gender-matched healthy controls.Surface electromyography (sEMG) was employed over the suprahyoid muscle group.Single swallow was applied twice with 5 and 10 ml of thin liquid barium as well as 5 and 10 ml of paste barium.The duration, average amplitude of sEMG and peak amplitude of submental muscle contraction were compared among three groups.Three-way analysis of variance (ANOVA) was performed. RESULTS: No significant differences existed in the general data among three groups (P > 0.05).However, all volumes, consistencies and durations [ (1.38 ± 0.21), (1.66 ± 0.30), (1.46 ± 0.24), (1.78 ± 0.28) s] were significantly longer for the group of dysphagia patients than for those without dysphagia and healthy subjects (P < 0.05).And the average amplitudes ( (16 ± 6), (15 ± 5), (20 ± 13), (19 ± 7) µV) were significantly smaller for the group of dysphagia patients than for those without dysphagia and healthy subjects (P < 0.05) while the peak amplitudes ((48 ± 23), (51 ± 23), (51 ± 31), (63 ± 32) µV) were significantly smaller for the group of dysphagia patients than for those without dysphagia and healthy subjects (P < 0.05). There were no significant differences between patients without dysphagia and those of healthy subjects (P > 0.05). CONCLUSION: As a simple and useful tool, sEMG is feasible for evaluating swallowing function and quantifying the strength of swallowing muscles in post-stroke patients with dysphagia.


Subject(s)
Deglutition Disorders/physiopathology , Facial Muscles/physiopathology , Stroke/physiopathology , Aged , Case-Control Studies , Electromyography , Female , Humans , Male , Middle Aged
16.
Zhen Ci Yan Jiu ; 38(2): 87-92, 2013 Apr.
Article in Chinese | MEDLINE | ID: mdl-23819208

ABSTRACT

OBJECTIVE: To observe the effect of electroacupuncture (EA) on the expression of myocardial 1-phosphatidylinositol 3-kinase (PI 3 K), hypoxia-inducible factor-1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) in rats with cerebral-cardiac syndrome (CCS), so as to reveal its mechanism underlying reducing ischemic myocardial injury. METHODS: Forty SD rats were randomly and equally divided into sham-operation, model, EA and non-acupoint (the lateral-superior side of the hip) groups (10 rats/group). CCS model was established by injection of collagenase (1 U/microL) and heparin (7 U/microL) into the right caudate nucleus. Following modeling, EA (1.5 mA, 2 Hz, 20 min) was applied to "Shuigou" (GV 26), "Fengfu" (GV 16), "Neiguan" (PC 6) and "Xinshu" (BL 15) acupoints, once daily for three consecutive days. The expression levels of PI 3 K,HIF-1alpha and VEGF in the myocardium were detected by immunohistochemistry. RESULTS: Compared with the sham-operation group, the expression levels of myocardial PI 3 K, HIF-1a and VEGF proteins were significantly increased in the model group (P<0.01). While in comparison with the model group, there were little increase in the non-acupoint group (P>0.05) and considerable increase in the expression levels of the 3 myocardial proteins in the EA group (P<0.05). CONCLUSION: EA intervention has a function in upregulating the expression of myocardial VEGF, HIF-1alpha and PI 3 K proteins in CCS rats, which maybe contribute to its protective effect on ischaemic myocardial injury.


Subject(s)
Cerebellar Diseases/genetics , Cerebellar Diseases/therapy , Electroacupuncture , Heart Diseases/genetics , Heart Diseases/therapy , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Phosphatidylinositol 3-Kinase/genetics , Vascular Endothelial Growth Factor A/genetics , Acupuncture Points , Animals , Cerebellar Diseases/metabolism , Female , Heart Diseases/metabolism , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Male , Phosphatidylinositol 3-Kinase/metabolism , Rats , Rats, Sprague-Dawley , Vascular Endothelial Growth Factor A/metabolism
17.
Anal Chem ; 84(21): 9199-207, 2012 Nov 06.
Article in English | MEDLINE | ID: mdl-23035833

ABSTRACT

A novel nonchromatographic speciation technique for ultratrace inorganic mercury (Hg(2+)) and methylmercury (CH(3)Hg(+)) in biological materials is developed and validated by electrolytic vapor generation (EVG) coupled with atomic fluorescence spectrometry (AFS). The studies show that CH(3)Hg(+) and Hg(2+) can be converted to Hg vapor efficiently on an l-cysteine modified graphite cathode, which has never been reported before. We observe that only Hg(2+) can be converted efficiently to Hg vapor at low current mode (0.2 A). While at high current mode (2.2 A), both CH(3)Hg(+) and Hg(2+) can be reduced efficiently. As a result, we successfully establish an exact and sensitive method based on the current control to detect mercury speciation for the first time. The factors of electrolytic conditions have been optimized, and the potential mechanism is discussed. Under the optimal conditions, the detection limits (3s) of Hg(2+) and CH(3)Hg(+) in aqueous solutions are 0.098 and 0.073 µg L(-1), respectively. The relative standard deviations for 6 replicate determinations of 2 µg L(-1) Hg are determined as 3.2% and 4.7% for Hg(2+) and CH(3)Hg(+). The accuracy of the method is verified through the analysis of certified reference materials (CRM, NRC-DORM-2), and the proposed method has been applied satisfactorily to the determination of mercury speciation in several seafood samples by calibration curve mode.


Subject(s)
Cysteine/chemistry , Electrochemistry/instrumentation , Graphite/chemistry , Methylmercury Compounds/chemistry , Electrodes , Food Analysis , Kinetics , Mercury/analysis , Mercury/chemistry , Spectrometry, Fluorescence , Volatilization
18.
Fen Zi Xi Bao Sheng Wu Xue Bao ; 41(5): 412-6, 2008 Oct.
Article in Chinese | MEDLINE | ID: mdl-19127777

ABSTRACT

In this report, we studied the fertilization and embryo development of a cross between rice and maize. The results showed that the pollen grains of maize could enter into the tissue of style of rice, and reached the embryo sac and released the sperms. Maize sperm might fuse with rice egg or polar nucleus and formed zygote or primary endosperm. But the embryo and endosperm could not be developed normally, and thus the underdeveloped hybrid seeds were formed. The reason was probably that the parental genomes could not coordinate well. This work provided a clue to solve the crossing obstacles between different species.


Subject(s)
Chimera/embryology , Chimera/genetics , Hybridization, Genetic/genetics , Oryza/genetics , Zea mays/genetics
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