Highly-sensitive electrochemiluminescence biosensor for detection of inosine monophosphate in meat based on graphdiyne/AuNPs/luminol nanocomposites

Inosine monophosphate(IMP),as a critical umami substance,is one of the most important indicators for evaluating the quality of meat products.Here,a sensitive electrochemiluminescence(ECL)biosensor based on graphdiyne(GDY)/AuNPs/luminol nanocomposites was constructed to detect IMP.The GDY/AuNPs/luminol nanocomposites were synthesized by using simple one-pot method.GDY utilized its 2D framework to disperse and fix gold nanoparticles,which inhibited the agglomeration of gold nanoparticles and greatly improved its stability and catalytic properties.Importantly,GDY/AuNPs/luminol nanocomposites showed excellent catalytic ability and superior ECL activity towards luminol-H_(2)O_(2) systems due to the synergistic effect of GDY and AuNPs.Under optimal conditions,the prepared biosensor exhibited a wide linear range from 0.01 g/L to 20 g/L,a satisfactory limit detection of 0.0013 g/L,as well as an excellent specificity.Moreover,we carried out the precise analysis of IMP in actual meat samples with acceptable results compared to the liquid chromatography.We believe that this work could offer an efficient ECL platform for accurate and reliable report of IMP levels,which is significant for maintaining food quality and safety.

双核Pt(Ⅳ)配合物与Guanosine-5′-Monophosphate和Glutathione反应的核磁共振光谱研究(英文)

合成了一个新型的双核Pt(Ⅳ)配合物｛[cis-Pt(NH3)2Cl(OH)2]2(4,4′-methylenedianiline)｝(NO3)2(化合物1)及相应的15N标记化合物｛[cis-Pt(15NH3)2Cl(OH)2]2(4,4′-methylenedianiline)｝(NO3)2(化合物15N-1)。利用1HNMR和ESMS进行了结构表征,化合物15N-1的2D[1H,15N]HSQCNMR发现,该化合物在水溶液中存在同分异构体。2D[1H,15N]HSQCNMR技术跟踪了化合物15N-1与Guanosine-5′-Monophosphate(5′-GMP)和Glutathione(GSH)的反应。结果显示,5′-GMP能在0.5h内将化合物1还原,而GSH在6h以后才能够部分的将化合物1还原。化合物1所表现出来的反应性能将有利于提高其治疗效果和降低毒副作用。

Effects of plant extract neferine on cyclic adenosine monophosphate and cyclic guanosine monophosphate levels in rabbit corpus cavernosum in vitro

Aim： To further investigate the relaxation mechanism of neferine （NED, a bis-benzylisoquinoline alkaloid extracted （isolated） from the green seed embryo of Nelumbo nucifera Gaertn in China, on rabbit corpus cavernosum tissue in vitro. Methods： The effects of Nef on the concentrations of cyclic adenosine monophosphate （cAMP） and cyclic guanosine monophosphate （cGMP） in isolated and incubated rabbit corpus cavernosum tissue were recorded using ^125I radioimmunoassay. Results： The basal concentration of cAMP in corpus cavernosum tissue was 5.67 ± 0.97 pmol/mg. Nef increased the cAMP concentration in a dose-dependent manner （P 〈 0.05）, but this effect was not inhibited by an adenylate cyclase inhibitor （cis-N-[2-phenylcyclopentyl]azacyclotridec-1-en-2-amine, MDL-12, 330A） （P 〉 0.05）. The accumulation of cAMP induced by prostaglandin Et （PGEt, a stimulator of cAMP production） was also augmented by Nef in a dose-dependent manner （P 〈 0.05）. The basal concentration of cGMP in corpus cavernosum tissue is 0.44 ± 0.09 pmol/mg. Nef did not affect this concentration of cGMP, either in the presence or in the absence of a guanyl cyclase inhibitor （1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, ODQ） （P 〉 0.05）. Also, sodium nitroprusside （SNP, a stimulator of cGMP production）-induced cGMP production was not enhanced by Nef （P 〉 0.05）. Conclusion： Nef, with its relaxation mechanism, can enhance the concentration of cAMP in rabbit corpus cavernosum tissue, probably by inhibiting phosphodiesterase activity. （Asian JAndro12008 Mar; 10： 307-312）

Low-power laser irradiation promotes the proliferation and osteogenic differentiation of human periodontal ligament cells via cyclic adenosine monophosphate

Retaining or improving periodontal ligament （PDL） function is crucial for restoring periodontal defects. The aim of this study was to evaluate the physiological effects of low-power laser irradiation （LPLI） on the proliferation and osteogenic differentiation of human PDL （hPDL） cells. Cultured hPDL cel Is were irradiated （660 nm） daily with doses of O, 1, 2 or 4 J .cm-2. Cell proliferation was evaluated by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide （MTT） assay, and the effect of LPLI on osteogenic differentiation was assessed by Alizarin Red S staining and alkaline phosphatase （ALP） activity. Additionally, osteogenic marker gene expression was confirmed by real-time reverse transcription-polymerase chain reaction （RT-PCR）. Our data showed that LPLI at a dose of 2 J.cm-2 significantly promoted hPDL cell proliferation at days 3 and 5. In addition, LPLI at energy doses of 2 and 4 J.cm-2 showed potential osteogenic capacity, as it stimulated ALP activity, calcium deposition, and osteogenic gene expression. We also showed that cyclic adenosine monophosphate （cAMP） is a critical regulator of the LPLI-mediated effects on hPDL cells. This study shows that LPLI can promote the proliferation and osteogenic differentiation of hPDL cells. These results suggest the potential use of LPLI in clinical applications for periodontal tissue regeneration.

Icariin upregulates phosphorylated cyclic adenosine monophosphate response element binding protein levels in the hippocampus of the senescence-accelerated mouse

At 8 weeks after intragastric administration of icariin to senescence-accelerated mice （P8 strain）, Morris water maze results showed that escape latency was shortened, and the number of platform crossings was increased. Immunohistochemical staining and western blot assay detected significantly increased levels of cyclic adenosine monophosphate response element binding protein These results suggest that icariin upregulates phosphorylated cyclic adenosine monophosphate response element binding protein levels and improves learning and memory functions in hippocampus of the senescence-accelerated mouse.

Existence of Heme Oxygenase-carbon Monoxide-cyclic Guanosine Monophosphate Pathway in Human Trabecular Meshwork Cells In Vitro

To confirm the existence of heme oxygenase (HO)-carbon monoxide (CO)- cyclic guanosine monophosphate (cGMP) pathway in the cultured human trabecular meshwork cells (HTMCs) in vitro, and to evaluate the inductive role of hemin on this pathway, HTMCs of the third to fourth generation were cultured in vitro. Reverse transcripase-polymerase chain reaction (RT-PCR) was employed for detection of HO-1 and HO-2 mRNA. Immunohistochemical staining was used to detect HO-1 and HO-2 proteins. Hemin was added into the culture solution. The HO-1 mRNA levels were quantified by RT-PCR. The relative amount of carbon monoxide released into the media was measured with the quantifying carbon monoxide hemoglobin (HbCO) by spectrophotometry. Radioimmunoassay was used to determine changes of cGMP in HTMCs. The results showed that cultured cells had the specific characteristics of HTMCs. Both HO-1 and HO-2 genes were expressed in HTMCs, as well as HO-1 and HO-2 proteins in HTMCs. Hemin induced HO-1 mRNA, HbCO and cGMP in a dose-dependent manner. In conclusion, HO-CO-cGMP pathway exists in the cultured HTMCs and can be induced by hemin. Pharmacological stimulation of HO-CO-cGMP pathway may constitute a novel therapeutic approach to rescuing glaucoma.

Analysis of the nitric oxide-cyclic guanosine monophosphate pathway in experimental liver cirrhosis suggests phosphodiesterase-5 as potential target to treat portal hypertension

AIM To investigate the potential effect of inhibitors of phosphodiesterase-5(PDE-5) for therapy of portal hypertension in liver cirrhosis.METHODS In the rat model of thioacetamide-induced liver fibrosis/cirrhosis the nitric oxide-cyclic guanosine monophosphate(NO-cGMP) pathway was investigated. Expression and localization of PDE-5, the enzyme that converts vasodilating cGMP into inactive 5'-GMP, was in the focus of the study. Hepatic gene expression of key components of the NO-cGMP pathway was determined by qRT-PCR: Endothelial NO synthase(eNOS), inducible NO synthase(iNOS), soluble guanylate cyclase subunits α1 and β1(sGCa1, sGCb1), and PDE-5. Hepatic PDE-5 protein expression and localization were detected by immunohistochemistry. Serum cGMP concentrations were measured using ELISA. Acute effects of the PDE-5 inhibitor Sildenafil(0.1 mg/kg or 1.0 mg/kg) on portal and systemic hemodynamics were investigated using pressure transducers.RESULTS Hepatic gene expression of eNOS(2.2-fold; P = 0.003), sGCa1(1.7-fold; P = 0.003), sGCb1(3.0-fold; P = 0.003), and PDE-5(11-fold; P = 0.003) was increased in cirrhotic livers compared to healthy livers. Overexpression of PDE-5(7.7-fold; P = 0.006) was less pronounced in fibrotic livers. iNOS expression was only detected in fibrotic and cirrhotic livers. In healthy liver, PDE-5 protein was localized primarily in zone 3 hepatocytes and to a lesser extent in perisinusoidal cells. This zonation was disturbed in cirrhosis: PDE-5 protein expression in perisinusoidal cells was induced approximately 8-fold. In addition, PDE-5-expressing cells were also found in fibrous septa. Serum cGMP concentrations were reduced in rats with cirrhotic livers by approximately 40%. Inhibition of PDE-5 by Sildenafil caused a significant increase in serum cGMP concentrations [+ 64% in healthy rats(P = 0.024), + 85% in cirrhotic rats(P = 0.018)]. Concomitantly, the portal venous pressure was reduced by 19% in rats with liver cirrhosis. CONCLUSION Overexpression and abrogated zonation of PDE-5 likely contribute to the pathogenesis of cirrhotic portal hypertension. PDE-5 inhibition may therefore be a reasonable therapeutic approach for portal hypertension.

ADSL, AMPD1, and ATIC Expression Levels in Muscle and Their Correlations with Muscle Inosine Monophosphate Content in Dapulian and Hybridized Pig Species

We investigated the relationship between muscle inosine monophosphate (IMP) content and mRNA levels of ADSL, AMPD1, and ATIC in Dapulian (DPL), Landrace × Dapulian (LDPL), and Duroc × Landrace × Dapulian (DLDPL) hybridized pigs. Methods: The total RNA in longissimus dorsi was isolated from Dapulian (DPL), Landrace × Dapulian (LDPL) and Duroc × Landrace × Dapulian (DLDPL) hybridized pigs, weighed about 95.0 kg, n = 8/species. The internal genes with highest stability (YWHAZ and RPL4) were chosen from 11 common internal genes using Quantitative real-time PCR (qPCR) and geNorm software. The mRNA levels of ADSL, AMPD1 and ATIC genes were corrected with YWHAZ and RPL4 genes. The muscular IMP content was determined by HPLC. The muscular IMP content in DPL was higher than that in LDPL and DLDPL, 25.00% (p 0.05) and 15.56% (p > 0.05), respectively. The muscular mRNA level of ADSL gene in DPL and LDPL was higher than that in DLDPL, 24.14% and 12.07%, respectively (p 0.05). The muscular mRNA level of ATIC gene in DPL and LDPL was higher than that in DLDPL, 66.67% and 33.33%, respectively (p 0.05). The muscular mRNA level of AMPD1 gene in DPL and LDPL was higher than that in DLDPL, 14.49% and 33.26%, respectively. Furthermore, the IMP content was positively correlated with the mRNA level of ADSL, AMPD1 and ATIC genes, respectively (p 0.05). The mRNA level of ADSL gene was highly related to that of AMPD1 and ATIC gene, respectively (p 0.01), while that of AMPD1 gene was not strongly correlated with that of ATIC gene (p > 0.05). The muscular mRNA level of AMPD1, ADSL and ATIC genes and the muscular IMP content in DPL were highest, followed by those in LDPL and DLDPL. The muscular IMP content was positively correlated with the muscular mRNA level of ADSL, AMPD1 and ATIC genes, respectively.

Efficient production of cyclic adenosine monophosphate from adenosine triphosphate by the N-terminal half of adenylate cyclase from Escherichia coli

In this study,we aimed at developing an efficient biocatalytic process for bio-production of cyclic adenosine monophosphate(c AMP)from adenosine triphosphate(ATP).First,adenylate cyclase from Escherichia coli MG1655(EAC)and Bordetella Pertussis(BAC)were expressed in E.coli BL21(DE3)and comparatively analyzed for their activities.As a result,EAC from E.coli MG1655 exhibited a higher activity.However,amount of EAC were obtained in an insoluble form.Therefore,we expressed the first 446 amino acids of EAC(EAC446)to avoid the inclusion body.The effects of induction temperature,incubation time,and incubation p H were further evaluated to improve the expression of EAC446.Subsequently,the reaction process for the production of c AMP with ATP as a starting material was investigated.As none of c AMP was detected in the whole-cell based biocatalytic process,the reaction catalyzed by the crude enzyme was determined for c AMP production.What's more,the reaction temperature,reaction p H,metal ion additives and substrate concentration was optimized,and the maximum c AMP production of 18.45 g·L^-1was achieved with a yield of 95.4%after bioconversion of 6 h.

Symptomatic improvement in an acute, non-traumatic spine pain model with a combination of uridine triphosphate, cytidine monophosphate, and hydroxocobalamin

Rationale: In a previously published trial on spinal acute non-traumatic pain, peripheral neuro- regenerative combination of UTP, CMP and hydroxocobalamin presented unexpected analgesicproperties. Objective: To corroborate analgesiceffects of UTP, CMP and hydroxocobalamin combination in a self-paired evolutionary model. Methods: Mean VAS scores from pretreatment, V2 (5th treatment day) and V3 (10th treatment day) were plotted and statistically analyzed (ANOVA) for differences. PFQ scores from pretreatment, V2, and V3 were analyzed using the chisquare test. Results: The difference between V3 and pretreatment mean VAS scores was statistically significant (p < 0.0001). The improvement in PFQ scores throughout the study was found to be statistically significant (p < 0.0001). Conclusion: The combination of UTP, CMP and hydroxocobalamin seems to have analgesic properties in mediumterm use. The complex peripheral neu-roregenerative pharmacodynamics of this combination provides a plausible basis for this finding. Further randomized studies are needed to explore this combination for the indication of neuropathic pain due to spinal structure involvement.

Diabetes and inflammatory diseases:An overview from the perspective of Ca^(2+)/3'-5'-cyclic adenosine monophosphate signaling

A large amount of evidence has supported a clinical link between diabetes and inflammatory diseases,e.g.,cancer,dementia,and hypertension.In addition,it is also suggested that dysregulations related to Ca^(2+)signaling could link these diseases,in addition to 3'-5'-cyclic adenosine monophosphate(cAMP)signaling pathways.Thus,revealing this interplay between diabetes and inflammatory diseases may provide novel insights into the pathogenesis of these diseases.Publications involving signaling pathways related to Ca^(2+)and cAMP,inflammation,diabetes,dementia,cancer,and hypertension(alone or combined)were collected by searching PubMed and EMBASE.Both signaling pathways,Ca^(2+)and cAMP signaling,control the release of neurotransmitters and hormones,in addition to neurodegeneration,and tumor growth.Furthermore,there is a clear relationship between Ca^(2+)signaling,e.g.,increased Ca^(2+)signals,and inflammatory responses.cAMP also regulates pro-and anti-inflammatory responses.Due to the experience of our group in this field,this article discusses the role of Ca^(2+)and cAMP signaling in the correlation between diabetes and inflammatory diseases,including its pharmacological implications.As a novelty,this article also includes:(1)A timeline of the major events in Ca^(2+)/cAMP signaling;and(2)As coronavirus disease 2019(COVID-19)is an emerging and rapidly evolving situation,this article also discusses recent reports on the role of Ca^(2+)channel blockers for preventing Ca^(2+)signaling disruption due to COVID-19,including the correlation between COVID-19 and diabetes.

Sevoflurane effects on cyclic adenosine monophosphate response element binding protein,phosphorylated cyclic adenosine monophosphate response element binding protein,and Livin expression in the cortex and hippocampus of a vascular cognitive impairment rat

BACKGROUND： Neuronal necrosis and apoptosis play important roles in the pathophysiology of cerebral ischemia and resulting cognitive impairment. However, inhibition of neuronal necrosis and apoptosis has been shown to attenuate cognitive impairment following cerebral ischemia. OBJECTIVE： To investigate the effects of sevoflurane on cyclic adenosine monophosphate response element binding protein （CREB）, phosphorylated CREB （pCREB）, and Livin expression in the cortex and hippocampus of a rat model of vascular cognitive impairment.DESIGN, TIME AND SETTING： A randomized, controlled experiment was performed in the Chongqing Key Laboratory of Neurology between June 2007 and July 2008.MATERIALS： Sevoflurane was provided by Abbott Laboratory, UK; Morris water maze was provided by Chinese Academy of Medical Sciences, China; goat anti-rat CREB, goat anti-rat pCREB and goat anti-rat Livin antibodies were provided by Biosource International, USA. METHODS： A total of 42 female, Wistar rats were randomly assigned to the following groups： sham operation, vascular cognitive impairment, and sevoflurane treatment. The vascular cognitive impairment rat model was established by permanent bilateral occlusion of both common carotid arteries, and 1.0 MAC sevoflurane was immediately administered by inhalation for 2 hours. MAIN OUTCOME MEASURES： CREB, pCREB, and Livin expression was measured in the cortex and hippocampus by Western blot and reverse transcription-polymerase chain reaction. Behavior was evaluated with Morris water maze. RESULTS： CREB, pCREB, and Livin expression in the sevoflurane treatment group was significantly greater than the vascular cognitive impairment group （P 〈 0.01）. However, expression of CREB and pCREB was significantly less in the sevoflurane treatment and vascular cognitive impairment groups, compared with the sham operation group （P 〈 0.01）. Livin expression in the sevoflurane treatment and vascular cognitive impairment groups was significantly greater than the sham operation group （P 〈 0.01）. Learning, memory, and behavior disorders were observed in the vascular cognitive impairment group. Sevoflurane treatment significantly improved these observed disorders. CONCLUSION： Sevoflurane improved cognitive impairment due to permanent bilateral occlusion of both common carotid arteries. Improved function was associated with increased CREB, pCREB, and Livin expression in the cortex and hippocampus.

Cyclic adenosine monophosphate signal pathway is involved in regulation of triacylglycerol biosynthesis following nitrogen deprivation in Chlamydomonas reinhardtii

The unicellular green alga,Chlamydomonas reinhardtii is a model organism for studying various biological processes,such as photosynthesis,flagellar motility,and lipid metabolism.To find some novel genes regulating the lipid metabolism under various stress conditions,the paromomycin resistance gene aphVIII was transferred into the genome of C.reinhardtii to establish a mutant library.Two genes mutated in two of the TAG-reduced mutants(Cre06.g278111 in M2 mutant,Cre06.g278110 in M6 mutants)were neighboring in the genome,and their expression levels were down-regulated in their corresponding mutants in parallel with their reduced TAG levels following N deprivation.The proteins encoded by these two genes(KCN11 by Cre06.g278111,ACYC3 by Cre06.g278110)contained a conversed cyclic mononucleotide phosphate(cNMP)binding protein and an adenylate domain,respectively.Since cNMP binding protein and adenylate domain have been known as important components of cyclic adenosine monophosphate(cAMP)signaling pathway,suggesting that these two genes might af fect cellular TAG biosynthesis through cAMP signal pathway.

Studies on Relationship between Serum Nitric Oxide and Plasma Cyclic Guanosine Monophosphate and Prolonged Bleeding after Medical Abortion as well as Prophylaxis and Treatment of Bleeding with Traditional

Objectives To study the relationship between serum nitric oxide (NO and plasma cyclic guanosine monophosphate (cGMP) and prolonged bleeding after medical abortion. Methods A total of 120 women having received medical abortions at random were recruited and divided into two groups: the one (Group A,n=60) taking 'Gong Fu Mixture(Uterus Recovering Mixture)' and the other (Group B,n=60) not taking it after abortion. On d 10, 20 and 30 after medical abortion, serum NO and plasma cGMP were tested before and after mifepristone administration and 10 d later by Gresis reaction method and radioimmunoassay respectively. Results NO concentration in serum and cGMP concentration in plasma decreased significantly after taking mifepristone given (P<0.05). Ten days later, the number of those with bleeding discontinuation in the group A was significantly greater than that in the group B (P<0.05). Serum NO level and plasma cGMP level in the group A decreased more significantly than those in the group B (P<0.05). Conclusion The slow decrease of serum NO and plasma cGMP is closely related to prolonged bleeding after medical abortion. “Gong Fu Mixture (uterus recovering mixture)” is effective in prevention and treatment of prolonged bleeding.

A New Mixed-metal Monophosphate:Ba2Bi2Co(PO4)4

A new member of mixed-metal Ba2Bi2M-Ⅱ（PO4）4 monophosphate, namely Ba2Bi2Co（PO4）4, was synthesized by solid state method and characterized by X-ray single-crystal diffraction and powder diffraction for the first time. It crystallizes in the orthorhombic system with space group Pnma（No. 62） and features a 3D architecture built up of adjacent zig-zag linear structures of [CoP4O（16）]∞ along [100], and further connected by [Bi2O（11）] dimers to form a 3D framework, where the Ba2＋ are located in the free space. The stereochemical activity of the Bi3＋ lone pair has also been discussed. The result of magnetic property measurement confirms the antiferromagnetic property of Ba2Bi2Co（PO4）4.

Absorption of Curcumin Monophosphate in Rat Intestinal Circulation

[Objectives] This study aimed to study the absorption of curcumin monophosphate, a derivative of curcumin, in the small intestine of rats. [Methods] In situ recirculation perfusion technique was used to study the absorption of curcumin monophosphate in intestinal circulation of rats, and the content of curcumin monophosphate in intestinal circulation solution was determined by high-performance liquid chromatography/ultraviolet detector(HPLC/UV). [Results] The established HPLC/UV method has good specificity. Linear regression was conducted between the peak area of curcumin monophosphate(A) and the concentration of curcumin monophosphate(C). The established standard curve equation was y=30.07x+102.48(R^2=0.999 0), indicating that curcumin monophosphate has good linearity in the range of 1.25-100.00 μg/mL. After excluding the degradation of the drug and the loss of sampling, within the first 2 h of the experiment, the drug absorption in the small intestine of rat was 1.39 mg, accounting for 97.2% of the total drug absorption during the 5-h experimental period, and the absorption rate was 53.9%.[Conclusions] Curcumin monophosphate has a good absorption in the small intestine of rats.

Transformation of microstructure and phase of disodium guanosine 5′-monophosphate: Thermodynamic perspectives

Microstructure and phase transformation of disodium guanosine 5′-monophosphate(5′-GMPNa_2) are extremely important for controlling the process and understanding the mechanism of crystallization. In this work, the thermodynamic properties of polymorphous 5′-GMPNa_2 especially the solubility were studied, the solubility results show that 5′-GMPNa_2 is more soluble in ethanol–water(E–W) than in isopropanol–water(I–W). The amorphous form of 5′-GMPNa_2 is more soluble than the crystalline form at the same mole fraction and temperature. Meanwhile, the crystalline forms and morphologies of the residual solids were characterized by PXRD and SEM. The results indicate that solid forms of 5′-GMPNa_2 transformed spontaneously from amorphous to crystalline when the ethanol proportion is ≥20%. In addition, increasing the pH facilitates the dissolution of 5′-GMPNa_2 and helps to maintain the crystalline form. The associated Gibbs free energy values were calculated to verify the trend of transformation from amorphous to crystalline 5′-GMPNa_2. These results should help to guide the industrial crystallization process and to obtain the crystalline form of 5′-GMPNa_2.

A unique insertion of low complexity amino acid sequence underlies protein-protein interaction in human malaria parasite orotate phosphoribosyltransferase and orotidine 5'-monophosphate decarboxylase

Objective:To investigate the multienzyine complex formation of human malaria parasite Plasmodium falciparum[P.falciparum)orotate phosphoribosyltransferase(OPRT)and orotidine5'-monophosphate decarboxylase(OMPDC),the fifth and sixth enzyme of the de novo pyrimidine biosynthetic palhway.Previously,we have clearly established that the two enzymes in the malaria parasite exist physically as a heterotetrameric(OPRT)_2(OMPDG)_2 complex containing two subunits each of OPRT and OMPDC.and that the complex have catalytic kinetic advantages over the monofunetional enzyme.Methods:Both enzymes were cloned and expressed as recombinant proteins.The protein-protein interaction in the enzyme complex was identified using bifunctionul chemical cross-linker,liquid chromatography-mass spectrometric analysis and homology modeling,Results:The unique insertions of low complexity region at the a 2 and a 5 helices of the parasite OMPDC,characterized by single amino acid repeat sequence which was not found in homologous proteins from other organisms,was located on the OPRT-OMPDC interface.The structural models for the protein-prolein interaction of the helerotetrameric(OPRT)_2(OMPDC)_2multienzyme complex were proposed.Conclusions:Based on the proteomic data and structural modeling,it is surmised that the human malaria parasite low complexity region is responsible for the OPRT-OMPDC interaction.The structural complex of the parasite enzymes,thus,represents an efficient functional kinetic advantage,which in line with co-localization principles of evolutional origin,and allosteric control in protein-protein-interactions.

Electroacupuncture preconditioning attenuates ischemic brain injury by activation of the adenosine monophosphate-activated protein kinase signaling pathway

Electroacupuncture has therapeutic effects on ischemic brain injury, but its mechanism is still poorly understood. In this study, mice were stimulated by electroacupuncture at the Baihui（GV20） acupoint for 30 minutes at 1 m A and 2/15 Hz for 5 consecutive days. A cerebral ischemia model was established by ligating the bilateral common carotid artery for 15 minutes. At 72 hours after injury, neuronal injury in the mouse hippocampus had lessened, and the number of terminal deoxynucleotide transferase-mediated d UTP nick-end labeling-positive cells reduced after electroacupuncture treatment. Moreover, expression of adenosine monophosphate-activated protein kinase α（AMPKα） and phosphorylated AMPKα was up-regulated. Intraperitoneal injection of the AMPK antagonist, compound C, suppressed this phenomenon. Our findings suggest that electroacupuncture preconditioning alleviates ischemic brain injury via AMPK activation.