Modular engineering of Escherichia coli for high-level production of l-tryptophan / 生物工程学报

As an essential amino acid, l-tryptophan is widely used in food, feed and medicine sectors. Nowadays, microbial l-tryptophan production suffers from low productivity and yield. Here we construct a chassis E. coli TRP3 producing 11.80 g/L l-tryptophan, which was generated by knocking out the l-tryptophan operon repressor protein (trpR) and the l-tryptophan attenuator (trpL), and introducing the feedback-resistant mutant aroGfbr. On this basis, the l-tryptophan biosynthesis pathway was divided into three modules, including the central metabolic pathway module, the shikimic acid pathway to chorismate module and the chorismate to tryptophan module. Then we used promoter engineering approach to balance the three modules and obtained an engineered E. coli TRP9. After fed-batch cultures in a 5 L fermentor, tryptophan titer reached to 36.08 g/L, with a yield of 18.55%, which reached 81.7% of the maximum theoretical yield. The tryptophan producing strain with high yield laid a good foundation for large-scale production of tryptophan.

Development and validation of ID-LC-MS/MS method for L-tryptophan and its metabolites / 中华检验医学杂志

Objective:To establish an isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) method for the determination of L-tryptophan and its metabolites in serum.Methods:The methodology was established and evaluated using serum samples collected from 166 healthy subjects undergoing physical examinations at West China Hospital from November 2022 to January 2023 were collected. Isotope-labeled markers of L-tryptophan (Trp), L-kynurenine (Kyn), and kynurenic acid (KA) were used as internal standards. After protein precipitation treatment of serum samples, LC-MS/MS was used to determine Trp, Kyn, and KA simultaneously. The selectivity, specificity, linearity, detection limit (LOD), quantification limit (LOQ), carry-over, precision, recovery rate, matrix effect, and dilution integrity of the method were evaluated.Results:The linearity of Trp, Kyn, and KA was demonstrated to be 0.999. The LODs were 0.10 μmol/L, 0.01 μmol/L and 1.00 nmol/L, respectively. The LOQs were 0.20 μmol/L, 0.04 μmol/L and 2.00 nmol/L, respectively. The intra-batch precision and inter-batch precision were below<10%. The average recovery rate and the relative matrix effect were all about 100%. The samples over the upper limit of quantitation can be diluted up to 16 times. The Trp concentration, Kyn concentration, KA concentration, Kyn/Trp ratio, and KA/Kyn ratio in serum of healthy subjects were 59.55±10.92 μmol/L, 1.85±0.43 μmol/L, 39.89±17.93 nmol/L, (31.64±8.19)×10 -3 and 21.51±6.72, respectively. Conclusion:An ID-LC-MS/MS method was successfully established for the quantitative determination of Trp, Kyn, and KA in serum. The method proved to be simple, rapid, sensitive, accurate, and reliable, providing robust support for clinical research related to these analytes.

Evolution of blood-brain barrier in brain diseases and related systemic nanoscale brain-targeting drug delivery strategies

Blood-brain barrier (BBB) strictly controls matter exchange between blood and brain, and severely limits brain penetration of systemically administered drugs, resulting in ineffective drug therapy of brain diseases. However, during the onset and progression of brain diseases, BBB alterations evolve inevitably. In this review, we focus on nanoscale brain-targeting drug delivery strategies designed based on BBB evolutions and related applications in various brain diseases including Alzheimer's disease, Parkinson's disease, epilepsy, stroke, traumatic brain injury and brain tumor. The advances on optimization of small molecules for BBB crossing and non-systemic administration routes (

Acute and chronic bovine pulmonary edema and emphysema in Uruguay / Edema e enfisema pulmonar agudo e crônico em bovinos do Uruguai

An outbreak of pulmonary edema and emphysema with acute and chronic cases is reported in a farm in Uruguay. In a herd of 40 Hereford steers, 20 died. The deaths began four days after a change of paddock, from an old pasture of Avena sativa to a lush growing pasture of the same grass. Acutely affected animals showed severe dyspnea, sialorrhea, cough, and subcutaneous edema, and died within 72 hours. Chronically affected steers showed dyspnea, respiratory noises, weight loss, and intolerance to exercise. The deaths began four days after the change of paddock. Ten days after the first death, the steers were withdrawn from the pasture, but continued dying throughout the following 40 days. Twenty animals died and six were necropsied. Grossly, the lungs were diffusely armed and glistening, with reddish and crepitant cut surface, and presented alveolar septae sharply distended by edema and emphysema. There was subpleural emphysema with air blebs distributed across the pleural surface. Presence of Dictyocaulus viviparus was observed in three steers. In some animals, the trachea was diffusely reddish with presence of pink foam; in some others, there was bloody liquid in the tracheal lumen. Histologic examination showed severe diffuse alveolar and interstitial emphysema, hyaline membranes adhered to the alveolar wall, thickening of the interlobular septae with proliferation of type II pneumocytes, and moderate-to-severe multifocal histiocytic, neutrophilic and eosinophilic infiltrate. In the trachea, there was submucosal hemorrhage and moderate multifocal eosinophilic and lymphocytic infiltrate. The steers with chronic signs presented similar lung lesions, but multifocal pulmonary fibrosis and cardiac dilatation were also observed. The diagnosis of acute bovine pulmonary emphysema and edema (ABPE) was based on the occurrence of the disease after introduction of the herd in a lush green pasture, on the characteristic gross and histologic lesions, and on the absence of other toxic or infectious agents causing similar lesions. Cattle raisers should be alert to the risks of occurrence of this disease after the introduction of the herds into paddocks with green and lush pastures.(AU)

Descreve-se um surto de edema e enfisema pulmonar com casos agudos e crônicos em bovinos em uma criação semi-intensiva no Uruguai. De um lote de 40 novilhos da raça Hereford morreram 20. As mortes começaram quatro dias após uma mudança de alimentação, de uma pastagem mais velha de Avena sativa, para uma pastagem recentemente plantada de aveia que estava em brotação. Os animais afetados apresentaram sinais clínicos agudos de dispneia, sialorreia, tosse e alguns desenvolveram edema subcutâneo, morrendo em até 72 horas. Outros novilhos mais cronicamente afetados apresentaram dispneia, ruídos respiratórios, perda de peso e intolerância ao exercício. As mortes começaram quatro dias após a mudança de pastagens. Dez dias após a primeira morte, os novilhos foram retirados do pasto, mas morreram ainda durante 40 dias mais. Ao total, morreram vinte animais e seis foram necropsiados. Nas necropsias dos animais mortos na fase aguda os pulmões estavam difusamente armados e brilhosos e ao corte de coloração avermelhada e crepitante, com os septos alveolares acentuadamente distendidos por edema e enfisema. Havia enfisema subpleural caracterizado por bolhas de ar distribuídas pela superfície pleural. Em três bovinos havia ainda presença de Dictyocaulus viviparus. Alguns animais apresentaram a traqueia difusamente avermelhada com espuma de coloração rósea ou liquido sanguinolento livre na luz traqueal. Histologicamente havia edema e enfisema alveolar e intersticial difuso severo, membranas hialinas espessas aderidas à parede alveolar, espessamento dos septos interlobulares com proliferação de pneumócitos tipo II e infiltrado inflamatório histiocítico, neutrofílico e eosinofílico multifocal moderado a severo. Na traqueia havia hemorragias na submucosa e infiltrado eosinofílico e linfocítico multifocal. Os novilhos com sinais crônicos apresentaram lesões pulmonares semelhantes, entretanto, foram observadas também, fibrose pulmonar multifocal e dilatação cardíaca. O diagnóstico de EEPAB baseou-se na ocorrência da doença após a introdução do rebanho em uma pastagem viçosa em brotação, nas características macroscópicas e histológicas e na ausência de outros agentes tóxicos ou infecciosos que causam lesões semelhantes. Se alerta para os riscos da ocorrência desta enfermidade, quando houver mudanças de pastagens.(AU)

Removing the by-products acetic acid and NH4 + from the L-tryptophan broth by vacuum thin film evaporation during L-tryptophan production

Background: During L-tryptophan production by Escherichia coli, the by-products, acetic acid and NH4 +, accumulate in the fermentation broth, resulting in inhibited cell growth and activity and decreased L-tryptophan production. To improve the L-tryptophan yield and glucose conversion rate, acetic acid and NH4 + were removed under low-temperature vacuum conditions by vacuum scraper concentrator evaporation; the fermentation broth after evaporation was pressed into another fermenter to continue fermentation. To increase the volatilisation rate of acetic acid and NH4 + and reduce damage to bacteria during evaporation, different vacuum evaporation conditions were studied. Results: The optimum operating conditions were as follows: vacuum degree, 720 mm Hg; concentration ratio, 10%; temperature, 60°C; and feeding rate, 300 mL/min. The biomass yield of the control fermentation (CF) and fermentation by vacuum evaporation (VEF) broths was 55.1 g/L and 58.3 g/L at 38 h, respectively, (an increase of 5.8%); the living biomass yield increased from 8.9 (CF) to 10.2 pF (VEF; an increase of 14.6%). L-tryptophan production increased from 50.2 g/L (CF) to 60.2 g/L (VEF) (an increase of 19.9%), and glucose conversion increased from 18.2% (CF) to 19.5% (VEF; an increase of 7.1%). The acetic acid concentrations were 2.74 g/L and 6.70 g/L, and the NH4 + concentrations were 85.3 mmol/L and 130.9 mmol/L in VEF and CF broths, respectively. Conclusions: The acetic acid and NH4 + in the fermentation broth were quickly removed using the vacuum scraper concentrator, which reduced bacterial inhibition, enhanced bacterial activity, and improved the production of L-tryptophan and glucose conversion rate.

Development of a novel vector for cloning and expressing extremely toxic genes in Escherichia coli

Background: Escherichia coli has been widely used as a host to clone and express heterologous genes. However, there are few vectors available for cloning and expressing extremely toxic genes, which limits further basic and applied research on extremely toxic proteins. Results: In this study, a novel vector pAU10 was constructed in E. coli. pAU10 utilizes the combination of the efficient but highly repressible T7-lacO promoter/operator and the strong rrnBT2 transcriptional terminator upstream of the T7 promoter to strictly control unwanted transcription of the extremely toxic gene; in addition, the trp promoter/operator is oriented opposite to the T7 promoter to control the production of the antisense RNA that may block the translation of leaky mRNA. Without the supplementation of IPTG and L-tryptophan in the culture medium, transcription of the extremely toxic gene by the T7 promoter is highly repressed, and the trp promoter produces the antisense RNA, which strictly prevents unwanted expression of the extremely toxic protein in E. coli. With the supplementation of IPTG and L-tryptophan, the T7 promoter efficiently transcribes the extremely toxic gene, and the trp promoter does not produce the antisense RNA, ensuring efficient expression of the extremely toxic protein in E. coli. Tight regulation and efficiency of expression of an extremely toxic gene cloned in the vector pAU10 were confirmed by cloning and expressing the restriction endonuclease-encoding gene bamHI without its corresponding methylase gene in E. coli JM109(DE3). Conclusion: pAU10 is a good vector used for cloning and expressing extremely toxic genes in E. coli.

Chemical constituents from leaves of Elaeagnus mollis / 中草药

Objective: To study the chemical constituents in the leaves of Elaeagnus mollis. Methods: Their structures were identified on the basis of silica gel column chromatography and Sephadex LH-20 gel column chromatography, and HPLC methods were used for the separation and purification of chemical constituents. Results: Sixteen compounds were isolated from 70% ethanol extracts of the leaves of E. mollis. The structures were identified as kaempferol-3-O-β-D-glucopyranoside (1), kaempferol-3-O-(6″-O-trans-p-coumaroyl)-β-D- glucopyranoside (2), kaempferol-3-O-(6″-O-cis-p-coumaroyl)-β-D-glucopyranoside (3), quercetin-3-O-α-L-arabinopyranoside (4), kaempferol-7-O-α-L-rhamnopyranoside (5), kaempferol-3,7-di-O-α-L-rhamnopyranoside (6), kaempferol-3-O-β-D-galactopyranosyl-7- O-α-L-rhamnopyranoside (7), kaempferol-3-O-α-Larabinofuranosyl-7-O-α-L-rhamnopyranoside (8), hippophamide (9), L-tryptophan (10), arjunolicacid (11), ursolicacid (12), kaempferol (13), rutin (14), adenosine (15), and β-daucosterol (16). Conclusion: Compounds 3-10 and 15 are isolated from the plants of Elaeagnus L. for the first time. Compounds 1, 2, 11, and 12 are isolated from this plant for the first time.

Protective effect of N-acetyl-L-tryptophan on intestinal damage after rat hepatic ischemia reperfusion / 重庆医学

Objective To investigate the protective effects of N-acetyl-L-tryptophan (L-NAT) on intestinal damage after rat hepatic ischemia reperfusion.Methods Twenty-four healthy adult rats were divided into the sham operation group (Sham),ischemia reperfusion group (IR),ischemia reperfusion and N-acetyl-L-tryptophan group(IR+L-NAT).The hepatic ischemia reperfusion model was established by occluding the afferent vessels of the left and middle lobes.The morphological structures of the small intestine were observed by hematoxylin-eosin (HE) staining.The expressions of active caspase-3,Bax and Bcl-2 were detected by immunohistochemistry staining.Results (1) In the IR group,the structure of intestinal villis was destroyed,the intestinal mucosa showed congestion and exfoliation,the epithelial cells had degeneration and necrosis,and infiltration of inflammatory cells appeared;which could be alleviated by L-NAT.(2)The immunohistochemistry showed that compared with the Sham group,the expression of active caspase-3,Bcl-2 and Bax in the IR group was increased,after L-NAT intervention,the Bax and caspase-3 expression was decreased,while the Bcl-2 expression was further increased.Conclusion L-NAT could inhibit the apoptosis of small intestinal epithelial cells caused by liver ischemic reperfusion and attenuates intestinal epithelial damage.

Protective effect of N-acetyl-L-tryptophan on intestinal damage after rat hepatic ischemia reperfusion / 重庆医学

Objective To investigate the protective effects of N-acetyl-L-tryptophan (L-NAT) on intestinal damage after rat hepatic ischemia reperfusion.Methods Twenty-four healthy adult rats were divided into the sham operation group (Sham),ischemia reperfusion group (IR),ischemia reperfusion and N-acetyl-L-tryptophan group(IR+L-NAT).The hepatic ischemia reperfusion model was established by occluding the afferent vessels of the left and middle lobes.The morphological structures of the small intestine were observed by hematoxylin-eosin (HE) staining.The expressions of active caspase-3,Bax and Bcl-2 were detected by immunohistochemistry staining.Results (1) In the IR group,the structure of intestinal villis was destroyed,the intestinal mucosa showed congestion and exfoliation,the epithelial cells had degeneration and necrosis,and infiltration of inflammatory cells appeared;which could be alleviated by L-NAT.(2)The immunohistochemistry showed that compared with the Sham group,the expression of active caspase-3,Bcl-2 and Bax in the IR group was increased,after L-NAT intervention,the Bax and caspase-3 expression was decreased,while the Bcl-2 expression was further increased.Conclusion L-NAT could inhibit the apoptosis of small intestinal epithelial cells caused by liver ischemic reperfusion and attenuates intestinal epithelial damage.

Effect of PTS modifications on L-tryptophan production in Escherichia coli / 生物工程学报

L-tryptophan, one of the aromatic amino acids, is widely used in the fields of medicine, food and feed additives. The phosphoenolpyruvate-carbohydrate phosphotransferase system (PTS) plays an important role in glucose transport and phosphorylation in Escherichia coli. PTS-mediated regulation dominates the carbohydrates' uptake and metabolism in E. coli. We constructed L-tryptophan-producing bacteria containing two typical PTS mutations (ptsHIcrrglf⁻ glk⁺ and ptsG⁻) by Red homologous recombination system, and studied in 50 L jar fermenter using fed-batch fermentation. Both PTS system mutants had a great impact on the biomass (increasing 47.0% and 17.6%, respectively), L-tryptophan production (increasing 25.9% and 9.4%, respectively), glucose conversion rate (increasing 26.5% and 17.4%, respectively) and byproduct acetic acid generation (slightly increased and decreased，respectively).

Effect of L-tryptophan and its derivatives on cephalotaxine production in Cephalotaxu mannii suspension cells / 中草药

Objective: To investigate the effects of L-tryptophan and its derivative 5-methyl-DL-tryptophan (5-MT) on suspension cells growth and cephalotaxine production of Cephalotaxu mannii. Methods: The cell suspension cultures were treated with L-tryptophan and 5-MT on day 15, respectively. Then the cell growth, cephalotaxine production, and activity of key enzymes in the metabolism pathway were determined. Results: L-tryptophan and 5-MT could enhance cephalotaxine production. The cultures treated with 5 mg/L L-tryptophan showed the highest cephalotaxine yield (2.944 mg/L). While treated with 10 mg/L L-tryptophan and 5 mg/L 5-MT, the cephalotaxine yields were 1.947 and 2.192 times of the control culture (1.343 mg/L); The biomass of suspension cultures were decreased by 9.35% and 18.04%, respectively, less than those in the control group (2.406 g/L); The activity of 3-deoxy-D-arabino- heptulosonate-7-phosphate synthase was decreased by 12.4% and 5.57% compared with the control (0.67 U/mg); The activity of phenylalanine ammonium-lyase activity increased by 37.72% and 28.02% and the total phenolics content increased by 19.14% and 9.61% compared with the control (78.21 U/mg and 0.36 mg/mL). Conclusion: L-tryptophan and its derivative 5-MT can inhibit the L-tryptophan biosynthetic pathway and promote the accumulation of cephalotaxus alkaloids.

Determination of L-Tryptophan by Using Ordered Mesoporous Silica Modified Carbon Paste Electrode Based on Enhancement Effects of Surfactant / 分析化学

An ordered mesoporous silica ( OMS ) was synthesized through hydrothermal process. The synthesized material was characterized by different techniques such as X-ray diffraction, nitrogen adsorption-desorption and transmission electron microscope. The electrochemical characteristics of the OMS modified carbon paste electrode ( OMS/CPE ) were investigated by using cyclic voltammetry and electrochemical impedance spectroscopy. Compared with bare carbon paste electrode ( CPE ) , the OMS/CPE exhibited a larger electrode surface and a faster electron-transfer rate. Electrochemical behaviors and kinetic properties of L-tryptophan ( L-Trp) at the OMS/CPE in the presence of sodium dodecylsulphate ( SDS) were studied. The results showed that the voltammetric response of L-Trp at OMS/CPE was improved due to the synergistic effect of OMS and SDS. The electrochemical oxidation of L-Trp at OMS/CPE in the presence of SDS was an irreversible process involved two electrons and two protons, and the electrode process was controlled by the adsorption step. Some parameters such as SDS concentration, accumulation time, accumulation potential and pH were optimized. Under optimal conditions, the oxidation peak current was linearly proportional to L-Trp concentration in the range of 8. 0×10-8 to 4. 0×10-6 mol/L, with a detection limit of 7. 0×10-8 mol/L (S/N=3 ) . The proposed method was applied for the determination of L-Trp in oral liquid with the recoveries of 99 . 6%-102 . 6%.

Simultaneous determination of L-tryptophan and L-kynurenine in rat plasma by LC-MS/MS / 中国药科大学学报

@#To establish a simple and sensitive LC-MS/MS method for simultaneous determination of the concentration for L-tryptophan(L-Try)and L-kynurenine(L-Kyn)in rat plasma. The changesin the process of the liver tumors formation may provide a basis for the diagnosis of liver cancer. 3-Nitro-L-tyrosine(3-NT)were added as the internal standard for the determination of two active substances and the chromatographic analysis was performed on a RRHD Eclipse Plus C18 column(3. 0 mm×100 mm, 1. 8 μm). The mobile phase was composed of water and acetonitrile(containing 0. 1%formic acid)(90 ∶10)at a flow rate of 0. 25 mL/min, and the injection volume is 5 μL. Detection and quantification were performed by mass spectrometry in multiple reaction monitoring mode with m/z 205. 12→146. 10(L-Try), m/z 209. 09 →146. 10(L-Kyn), m/z 227. 09→181. 10(3-NT), respectively. The results show that thelinear ranges were 9. 670-9 670 ng/mL for L-Try, and 9. 973-9973 ng/mL for L-Kyn(r2≥0. 9990). The limit of quantitation were 9. 670 ng/mL for L-Try, and 9. 973 ng/mL for L-Kyn, respectively. The intra- and inter-day precisions were all less than15%; the recoveries ofthe two analytes were more than 81. 17% and severe matrix effect was not observed. The ratio of L-Try/L-Kyn determined by LC-MS/MS in rat plasma showed an overall downward trend, which could used effectively for the drug metabolism studies and researches on the action mechanism of medicine on liver cancer. A rapid, simple, sensitive and specific LC-MS/MS method has been successfully developed and could also be used effectively for the drug metabolism studies and researches on the action mechanism of medicine on liver cancer.

Edema e enfisema pulmonar agudo em bovinos no Sul do Brasil: doença espontânea e reprodução experimental / Acute pulmonary edema and emphysema in cattle in Southern Brazil: spontaneous disease and experimental reproduction

The paper reports the epidemiological data, clinical signs and lesions of four outbreaks of acute pulmonary edema and emphysema in cattle (ABPE) which occurred in the states of Parana and Santa Catarina, as well as its experimental reproduction. The spontaneous disease occurred after the cattle was transferred from a mature and dry pasture to another luxurious sprouting one. All affected animals were adult dairy cows of Holstein and Brown Swiss breed. The main clinical signs were dyspnea of laborious abdominal breathing with extended neck and open mouth.The sick animals also presented subcutaneous emphysema, decreased milk production, slow recovery or death. Postmortem findings were restricted to a dark red not collapsed lung, which was shiny and hyper sizzling more than usual and with marked interlobular emphysema. Histological lesions in the lung consisted of alveolar and interlobular emphysema, areas with congestion and edema, hyaline degeneration of the alveolus wall and moderate diffuse infiltration of macrophages and eosinophils. The experimental reproduction of the disease was performed in a cow by orally administration of 0.7mg/kg /LW of L-Tryptophan single dose. The animal died on the seventh day of the experiment. The clinical signs and lesions were similar to those observed in the naturally occurring disease.

Descrevem-se os dados epidemiológicos, os sinais clínicos e as lesões de quatro surtos da doença do edema e enfisema pulmonar agudo em bovinos (EEPAB) nos estados de Santa Catarina e Paraná e sua reprodução experimental. A doença espontânea ocorreu após transferência de bovinos de pastagem madura e seca para outra jovem e viçosa. Todos os bovinos afetados eram vacas das raças holandês e pardo suíço. Os principais sinais clínicos foram dispneia e respiração abdominal dificultosa com o pescoço estendido e a boca aberta. Apresentaram, também, enfisema subcutâneo, queda na produção de leite e recuperação lenta ou morte. Os achados de necropsia foram restritos ao pulmão o qual tinha coloração vermelho escuro, não colabado, de aspecto brilhante e hipercriptante com enfisema interlobular acentuado. As lesões histológicas no pulmão consistiam principalmente de enfisema alveolar e interlobular intercalado por áreas de congestão e edema, degeneração hialina da parede dos alvéolos e infiltrado de macrófagos e eosinófilos, moderado, difuso. A reprodução experimental da doença foi realizada em um bovino, com administração de 0,7mg/kg de peso corporal de L-triptofano por via oral em dose única. O animal morreu no sétimo dia de experimento. Os sinais clínicos e lesões foram idênticos aos observados na doença espontânea.

Anti-depression effect of licorice flavonoids from Glycyrrhiza uralensis through promotion of central serotonergic neural function in mice / 中国药理学与毒理学杂志

OBJECTlVE To investigate the antidepressant effect and reIated mechanism of the totaI fIavonoids extract parts( Iicorice fIavonoids,LF)from Glycyrrhiza uralensisFisch. cuItivated IocaIIy in Ningxia. METHODS Forced swimming test( FST)and taiI suspension test( TST)were adopted to study the antidepressant pharmacoIogicaI effect in the acute stress-induced depression modeI in mice. The Km mice were intragastricaIIy administered with LF(5,30 and 180 mg·kg-1 )once daiIy,for 21 con-secutive days. One hour after the first,seventh and Iast administrations,the mice were submitted to FST by recording the immobiIity period within the Iast 4 min of the totaI 6 min in both tests and the resuIts were expressed as decrease in immobiIity period with respect to vehicIe controI. In TST,the other group of Km mice was used to evaIuate the antidepressant effect in same protocoI. In the antagonism of reserpine-induced symptoms test( ART),ICR mice were administered intragastricaIIy with LF( 50,150 and 400 mg·kg-1 )once daiIy for 7 consecutive days. One hour after the Iast administration,the mice received reserpine(4 mg·kg-1 ,ip),and ptosis or akinesia was measured 1 h after reserpine injection whiIe rectaI temperature was measured 4 h after the reserpine injection respectiveIy. The same protocoI was adopted in yohimbine toxicity potentiation test(YTT)as in ART. Thirty minutes fter the Iast adminis-tration,the mice received the threshoId IethaI dosage of yohimbine(30 mg·kg-1 ,sc)respectiveIy,and the death number of the mice was caIcuIated in 24 h after the yohimbine administration. In the 5-hydroxy-L-tryptophan(5-HTP)induced head-twitches test(HTT)in mice,after being administered intragastricaIIy with LF(50,150 and 400 mg·kg-1 )once daiIy for 7 consecutive days,the mice received pargiIine (100 mg·kg-1 ,ip)the next day,and 30 min Iater,5-HTP(10 mg·kg-1 ,ip)was intraperitoneaIIy injec-ted to induced the head twitch respectiveIy,and the times of head twitch in a 30 min period after 5-HTP treatment were observed at 6 time points. After HTT,the mice were sacrificed quickIy,and the mono-amine oxidase(mAO)activity in the brain cortex,hippocampus and thaIamus was examined to evaIuate the antidepressant effect of fIavonoids with mAO inhibition. RESULTS Compared with the vehicIe controI,LF significantIy decreased the immobiIity period in both FST and TST(P﹤0.05). LF(50,150 and 400 mg·kg-1 )antagonized the ptosis and akinesia symptoms respectiveIy in 1 h after reserpine administration( P ﹤ 0. 05 ), but faiIed to antagonize hypothermia produced 4 h after reserpine administration. AIso,at the same dosage,LF did not synergeticaIIy produce the enhancement of death by subcutaneous injection of yohimbine at the threshoId IethaI dosage. LF(150 and 400 mg·kg-1 )couId significantIy and synergeticaIIy increase 5-HTP induced head-twitches response(P﹤0.05),but LF couId not promote mAO activity in the cortex,hippocampus and thaIamus at the same dosage. CONCLUSlON LF exerts antidepressant-Iike effect on the modeI of acute despair test. The mechanism might be reIated to direct enhancement of the serotonergic neuraI function in the brain.

Determination of epristeride by its quenching effect on the fluorescence of L-tryptophan / 药物分析学报

A rapid, novel spectrofluorimetric method to determine epristeride (EP) in biological fluids and a pharmaceutical formulation was developed, based on the fact that fluorescence intensity of L-tryptophan could be quenched by EP in the medium of pH ? 9.0. The various factors influencing fluorescence quenching were discussed. The quenching mechanism was investigated with the quenching type, synchronous fluorescence spectra and quantum efficiency. Under the optimized conditions, fluorescence quenching value (ΔF ? FL-tryptophan-FEP-L-tryptophan) showed a good linear relationship with the EP concentration ranging from 0.4 to 12.0μg/mL. The linearity, recovery and limit of detection demonstrated that the proposed method was suitable for EP determination in biological fluids and EP tablets. The method was successfully applied to the analysis of EP in real samples and the obtained results were in good agreement with the results of the official method.

Chemical constituents from leaves of Datura metel (I) / 中草药

Objective: To study the chemical constituents in the leaves of Datura metel. Methods: The chemical constituents of ethanol extract from the leaves of D. metel were isolated and purified by chromatography over silica gel, AB-8 macroperous resin, ODS, Sephadex LH-20 columns, and RP-preparative HPLC. The structures were elucidated on the basis of physicochemical properties and spectral data analyses. Results: Forteen compounds were isolated and identified as naphthisoxazol A (1), congmuyaglyeoside I (2), L-tryptophan (3), quercetin3-O-2-(E-caffeoyl)-α-larabinopyranosyl- (1→2)-β-D-glucopyranoside-7-O-β-D-glucoside (4), n-butyl-O-α-D-fructofuranosidase (5), anoectochine (6), dihydrovomifoliol-O-β-D-glucoside (7), (6S, 7E, 9S)-9- [(β-D-glucopyranosyl)-oxy] megastigma-4, 7-dien-3-one (8), kaepmferol-3, 7-di-O-β-D-glucopyranoside (9), kaempferol-7-O-β-D-glucoside (10), quercetin-7-O-glucoside (11), (6S, 9R)-6-hydroxy-3-ketone-α-violet-grape alcohol-9-O-β-D-glucopyranoside (12), stigmasterol (13), and stigmasterol-3-O-β-D-glucoside (14). Conclusion: Compounds 1-8 are firstly found in the plants of Solanaceae.

Acute tryptophan administration impairs cortical spreading depression propagation in REM sleep deprived and non-deprived adult rats

The enhanced availability of tryptophan in the brain, as a consequence of exogenous tryptophan administration, can increase neuronal serotonin synthesis and this can interfere with brain function. REM sleep deprivation (D) constitutes another external factor that can change brain excitability, facilitating, in some cases, the manifestation of neurological diseases like epilepsy. Here we used cortical spreading depression (CSD) as a neurophysiological parameter to investigate the effects of a single L-tryptophan intraperitoneal injection combined or not with 72h D-condition (water-tank technique) in rats. A 1h baseline CSD-recording was performed under urethane+chloralose (1g/kg + 40mg/kg) anesthesia and revealed increased CSD propagation velocities in D rats, as compared with non-deprived (ND), or pseudo-deprived (Pseudo) controls. After the baseline CSD recording, L-tryptophan was immediately injected (125 mg/kg ip, dissolved in water at pH about 3) and this was followed by a significant decrease of CSD propagation velocities, as compared to the baseline values in the same animals of the Pseudo, ND and D condition. In an additional control group (ND rats injected with the vehicle), no CSD propagation change was seen. Our findings indicate an important acute antagonistic influence of tryptophan on CSD propagation, which is not affected by REM sleep deprivation. We suggest that this tryptophan effect may be due to a serotonin-mediated action, probably caused by increased serotonin synthesis as a consequence of enhanced tryptophan availability in the brain.

Positron Emission Tomography: Application in Pediatric Epilepsy / 대한간질학회지

No abstract available.

A Case of Eosinphilia-Myalgia Syndrome / 대한류마티스학회지

Eosinophilia-myalgia syndrome (EMS) is a multisystemic disorder characterized by severe myalgia and peripheral eosinophilia, and frequently accompanied by fasciitis, neuropathy and various cutaneous manifestations associated with consumption of L-tryptophan. Although EMS has not been uncommon in the United States, it has not been reported in Korea. We experienced a 28-year-old man who presented with severe myalgia, peripheral eosinophilia, right upper extremity motor weakness developed during ingestion of L-tryptophan containing food. He was diagnosed as EMS based on the diagnostic criteria by the Centers for Disease Control. His symptoms and laboratory findings including severe myalgia and eosinophilia rapidly improved after steroid treatment. To our knowledge, this is the first case report of EMS developed in L-tryprophan users in Korea. We report a case of EMS with a review of literature.