Genomic analyses of the Daphnia pulex peptidome

Genome mining has provided a valuable tool for peptide discovery in many species, yet no crustacean has undergone this analysis. Currently, the only crustacean with a sequenced genome is the cladoceran Daphnia pulex, a model organism in many fields of biology. Here, we have mined the D. pulex genome for peptide-encoding genes. For each gene identified, the encoded precursor protein was deduced, and its mature peptides predicted. Twenty-four peptide-encoding genes were identified, including ones predicted to produce members of the A-type allatostatin, B-type allatostatin, C-type allatostatin, allatotropin (ATR), bursicon α, bursicon β, calcitonin-like diuretic hormone, corazonin, crustacean cardioactive peptide, crustacean hyperglycemic hormone, ecdysis-triggering hormone, eclosion hormone (EH), insulin-like peptide (ILP), molt-inhibiting hormone, neuropeptide F, orcokinin (two genes), pigment-dispersing hormone, proctolin, red pigment concentrating hormone/adipokinetic hormone (RPCH/AKH), short neuropeptide F, SIFamide, sulfakinin, and tachykinin-related peptide (TRP) families/subfamilies. In total, 96 peptides were predicted from these genes. Our identification of isoforms of corazonin, EH, ILP, proctolin, RPCH/AKH, sulfakinin and TRP are the first for D. pulex, while our prediction of ATR from this species is the first from any crustacean. The number of peptides predicted in our study shows the power of genome mining for peptide discovery, and provides a model for future genomic analyses of the peptidomes of other crustaceans. In addition, the data presented in our study provide foundations for future molecular, biochemical, anatomical, and physiological investigation of peptidergic signaling in D. pulex and other cladoceran species.     

碱性成纤维细胞生长因子对缺血再灌注损伤后肠道细胞信号转导途径的影响

目的：观察给予外源性碱性成纤维细胞生长因子（bFGF)后大鼠肠道细胞信号转导途径细胞外信号调节激酶（p42/p44MAPK)活性的变化,并探讨外源性bFGF对大鼠肠缺血-再灌注（I-R）损伤保护作用的分子机制。方法：以大鼠肠系膜上动脉（SMA）夹闭造成肠道缺血-再灌注模型,并将动物随机分为假手术组,生理盐水对照组,bFGF抗体预处理组及bFGF治疗组,各组分别于缺血45分钟及再灌注后2、6、24和48小时活杀动物,取血及小肠组织标本,检测血浆中二胺氧化酶（DAO）含量及组织中磷酸化p42/p44MAPK的活性。结果：缺血-再灌注损伤可激活p42/p44MAPK信号转导途径,磷酸化p42/p44MAPK在小肠的绒毛及隐窝部的上皮细胞及绒毛的基质细胞中均有表达,与生理盐水对照组及bFGF抗体预处理组相比,bFGF治疗组磷酸化p42/p44MAPK的表达被快速激活,于再灌注后2小时即达高峰,而其它2组在6小时达峰值,血浆DAO变化及HE染色显示,再灌注后6小时肠屏障功能损伤最严重,而bFGF治疗组损伤在伤后48小时较其它2组有所减轻。结论：I-R损伤可激活p42/p44MAPK信号转导途径,而外源性bFGF可使p42/p44MAPK表达的峰值提前,提示bFGF对肠道缺血-再灌注损伤后屏障功能的保护作用可能与信号转导途径p42/p44MAPK的早期激活有关。     

Pathogens resistant to antibacterial agents

Resistance to antimicrobial drugs is increasing at an alarming rate among both gram-positive and gram-negative bacteria. Traditionally, bacteria resistant to multiple antimicrobial agents have been restricted to the nosocomial environment. A disturbing trend has been the recent emergence and spread of resistant pathogens in nursing homes, in the community, and in the hospital. This article reviews the epidemiology, molecular mechanisms of resistance, and treatment options for pathogens resistant to antimicrobial drugs.     

Prevalence of extended-spectrum beta-lactamases in Proteus mirabilis in a Taiwanese university hospital, 1999 to 2005: identification of a novel CTX-M enzyme (CTX-M-66)

A total of 1574 nonduplicate Proteus mirabilis isolates collected at a Taiwanese hospital during 1999 to 2005 were analyzed for production of extended-spectrum beta-lactamases (ESBLs). Forty-four ESBL-producing isolates including 22 CTX-M-14, 18 CTX-M-3, 2 CTX-M-24, and 2 CTX-M-66 producers were detected, and the proportion of ESBL producers increased from 0.7% in 1999 to approximately 6% after 2002. CTX-M-66 is a novel variant of CTX-M ESBLs that differs from CTX-M-3 by a Ser to Asn change at amino acid position 23. Coresistances to aminoglycosides and ciprofloxacin were very common in the CTX-M-3 producers. The presence of ArmA-type or RmtB-type 16S rRNA methylase that confers high-level aminoglycoside resistance was detected in 12 CTX-M-3 producers and 4 CTX-M-14 producers. Twenty-four clones including an endemic CTX-M-14-producing clone were observed among the 44 ESBL producers by pulsed-field gel electrophoresis, suggesting that both horizontal transfer and clonal spread contributed to the increased prevalence of bla(CTX-M) in P. mirabilis.     

Visfatin Protects Rat Pancreatic β-cells against IFN-γ-Induced Apoptosis through AMPK and ERK1/2 Signaling Pathways

ObjectiveInterferon-γ (IFN-γ) plays an important role in apoptosis and was shown to increase the risk of diabetes.Visfatin, an adipokine, has anti-diabetic, anti-tumor, and regulating inflammatory properties. In this study we investigated the effect of visfatin on IFN-γ-induced apoptosis in rat pancreatic β-cells. MethodsThe RINm5F (rat insulinoma cell line) cells exposed to IFN-γ were treated with or without visfatin. The viability and apoptosis of the cells were assessed by using MTT and flow cytometry. The expressionsof mRNA and protein were detected by using real-time PCR and western blot analysis. ResultsThe exposure of RINm5F cells to IFN-γ for 48 h led to increased apoptosis percentage of the cells. Visfatin pretreatment significantly increased the cellviability and reduced the cell apoptosis induced by IFN-γ. IFN-γ-induced increase in expression of p53 mRNA and cytochrome c protein, decrease in mRNA and protein levels of anti-apoptotic protein Bcl-2 were attenuated by visfatin pretreatment. Visfatin alsoincreasedAMPK and ERK1/2phosphorylation and the anti-apoptotic action of visfatin was attenuated by the AMPK and ERK1/2 inhibitor. ConclusionThese results suggested that visfatin protected pancreatic islet cells against IFN-γ-induced apoptosis via mitochondria-dependent apoptotic pathway. The anti-apoptotic action of visfatin is mediated by activation of AMPK and ERK1/2 signaling molecules.     

钙激活中性蛋白酶-2对整合素β4水解的影响

目的:观察乳腺癌细胞系MCF7细胞中,钙激活中性蛋白酶2(calpain-2)对整合素(integrin)β4水解的影响。方法:利用"短发夹"RNA(shRNA)和微小RNA(mirRNA)技术结合的calpain-2基因沉默(gene silencing)慢病毒质粒(GIPZ lentiviral shRNAmir)转染乳腺癌细胞株MCF7,嘌呤霉素筛选稳定沉默calpain-2基因的细胞株,细胞株传4代,用荧光显微镜观察转染效率,用蛋白质印迹(Western blot)实验检测calpain-2基因沉默效率及integrinβ4水解的情况。结果:嘌呤霉素筛选、细胞传4代,荧光显微镜下观察显示转染和筛选后,EGFP表达阳性的MCF7细胞的比例分别达到(95.6±2.6)%(空shRNAmir载体)、(97.1±1.7)%(Calpain-2 shRNAmir1)和(97.7±0.2)%(Calpain-2 shRNAmir 2),差异无统计学意义(P>0.05);Western blot结果显示,基因沉默的MCF7细胞中calpain-2的表达被明显抑制,相对于空shRNAmir载体转染的MCF7细胞,差异有统计学意义(P<0.01),calpain-2的表达下调到21.5%(Calpain-2 shRNAmir 1)和18.8%(Calpain-2 shRNAmir 2),空shRNAmir载体转染的MCF7细胞中calpain-2的表达与未转染的MCF7细胞比较,差异无统计学意义(P>0.05);比较calpain-2基因沉默和空shRNAmir载体转染的MCF7细胞,发现integrinβ4均被水解,水解片段的分子量主要有200 k D、130和95 k D;calpain-2基因沉默后,calpain-2基因沉默MCF7细胞中200 k D的水解片段比空shRNAmir载体转染的MCF7细胞减少(P<0.01)。结论:在乳腺癌细胞MCF7中,calpain-2可能参与integrinβ4的200 k D片段的形成,从而参与调整integrinβ4的构象变化。     

Comparing α7 nicotinic acetylcholine receptor binding,amyloid‐β deposition,and mitochondria complex‐I function in living brain: A PET study in aged monkeys

This study was aimed to assess the correlations among α7 nicotinic acetylcholine receptor (α7‐nAChR) binding, amyloid‐β (Aβ) deposition, and mitochondrial complex I (MC‐I) activity in the brain of aged monkeys (Macaca mulatta). Positron emission tomography (PET) measurements with [¹¹C](R)‐MeQAA, [¹¹C]PIB, and [¹⁸F]BCPP‐EF were conducted in monkeys in a conscious condition. [¹¹C](R)‐MeQAA binding was analyzed by a simplified reference tissue model to calculate nondisplaceable binding potential (BP_ND), [¹¹C]PIB uptake was calculated by standard uptake value ratio (SUVR), and [¹⁸F]BCPP‐EF binding was determined by Logan graphical analysis to calculate total distribution volume (V_T) with arterial blood sampling. Higher brain uptake was determined in the thalamus, hippocampus, striatum, and cortical regions for [¹¹C](R)‐MeQAA, while being lower in the cerebellum. Significant age‐related reduction of [¹¹C](R)‐MeQAA binding to α7‐nAChR was determined only in the occipital cortex. The plot of Vt of [¹⁸F]BCPP‐EF against BP_ND of [¹¹C](R)‐MeQAA indicated a significant negative correlation in the hippocampus and cortical regions in aged animals. Plotting of SUVR of [¹¹C]PIB against BP_ND of [¹¹C](R)‐MeQAA showed a positive correlation. The in vivo binding of [¹¹C](R)‐MeQAA could reflect the upregulation of α7‐nAChR induced by neurodegenerative damage determined by Aβ deposition as well as impaired MC‐I activity in living brain. Synapse 69:475–483, 2015. © 2015 Wiley Periodicals, Inc.     

Cdc42: Role in Cancer Management

Contribution of Cdc42, a member of Rho family, has been characterized for the beginning of variety of cellular responses including cellular transformation, cell division, cell invasion, migration, invadopodia formation, enzyme activity, filopodia formation, and cell polarity in cells. Deregulation of Cdc42 can alter the normal functioning of the cells, responsible for the initiation of signaling pathways and is correlated with several pathogenic processes such as cancer. Therefore, maintaining the level of Cdc42 and its effectors in cells, tumor progression can be controlled. Therefore, it can be suggested that deeper understanding about the Cdc42 contribution in cancer cell progression at molecular level can approach to the development of Cdc42 inhibitors in cancer management.     

电针对局灶性脑缺血再灌注大鼠皮质Slit-Robo三磷酸鸟苷酶激活蛋白-1和细胞分裂周期蛋白42表达的影响

目的:观察电针对大脑中动脉闭塞(MCAO)模型大鼠皮质Slit-Robo三磷酸鸟苷酶激活蛋白-1(Slit-Robo GTPase-activating protein-1,srGAP 1)和细胞分裂周期蛋白42(cell division-cycle 42,Cdc 42)表达的影响,探讨srGAP 1和Cdc 42在电针治疗MCAO后神经恢复中的作用。方法:雄性SD大鼠随机分为正常组、模型组、非经穴组和电针组,每组12只。利用改进的Longa法复制MCAO模型。电针组取"曲池""足三里"穴,非经穴组取手足阳明经与少阳经之间非经穴处,每日1次,每次30min,共14d。分别在术后1、3、7、14d时间点对各组大鼠进行神经功能评分(mNSS),并利用免疫荧光法检测缺血侧大脑皮质中srGAP 1和Cdc 42的荧光强度及分布,用免疫印迹(Western blot)法检测大鼠梗死区周围大脑皮质中srGAP1和Cdc 42蛋白表达。结果:神经功能评分显示,在术后7、14d时电针组较模型组、非经穴组同时间段的mNSS评分显著降低(P0.01)。免疫荧光检测结果显示,srGAP 1和Cdc 42主要在细胞质表达;模型组srGAP 1高于正常组(P0.01),而电针组显著低于模型组和非经穴组(P0.01);模型组Cdc 42显著低于正常组(P0.01),而电针组明显高于模型组和非经穴组(P0.01)。Western blot检测结果显示,模型组srGAP 1蛋白表达量较正常组明显升高(P0.01),电针组srGAP 1蛋白表达显著低于模型组及非经穴组(P0.01);模型组Cdc 42蛋白表达量与正常组的差异无统计学意义(P0.05),而电针组Cdc 42蛋白表达显著高于模型组和非经穴组(P0.01)。结论:局灶性脑缺血再灌注后大鼠脑损区周围皮质srGAP 1明显增高,而Cdc 42明显减少,这可能与srGAP 1使Cdc 42失活有关;电针治疗后srGAP 1显著下调,而Cdc42上调,可能是电针促进脑梗死后神经功能恢复的机制之一。