抗菌肽Bactenecin7重组质粒构建及其在乳酸菌的分泌表达和活性鉴定

构建抗菌肽Bactenecin7分泌表达载体,鉴定表达产物及检测其生物活性。采用重叠延伸PCR方法拼接合成Bactenecin7基因及其相关调控元件,将目的基因克隆到穿梭载体 pMG36e中,经鉴定后电击转化乳酸菌。通过RT PCR,Western blot检测目的基因表达情况,采用琼脂扩散法对表达产物的生物活性进行初步检测。结果显示成功构建了携Bactenecin7基因的重组质粒,将重组质粒转化至乳酸菌后,该乳酸菌能有效分泌表达Bactenecin7,经体外抑菌实验证实表达产物Bactenecin7具有抑菌活性。实验表明携Bactenecin7基因的乳酸菌能有效分泌表达具有生物活性的抗菌肽Bactenecin7,为进一步研究口服重组乳酸菌进行肠道细菌感染的治疗奠定了基础。     

The use of intensity‐based Doppler variance method for single vessel response to functional neurovascular activation

This study presents 1 use of optical coherence tomography (OCT) angiography technique to examine neurovascular coupling effect. Repeated B‐scans OCT recording is performed on the rat somatosensory cortex with cranial window preparation while its contralateral forepaw is electrically stimulated to activate the neurons in rest. We use an intensity‐based Doppler variance (IBDV) algorithm mapped cerebral blood vessels in the cortex, and the temporal alteration in blood perfusion during neurovascular activation is analyzed using the proposed IBDV quantitative parameters. By using principal component analysis‐based Fuzzy C Means clustering method, the stimulus‐evoked vasomotion patterns were classified into 3 categories. We found that the response time of small vessels (resting diameter 14.9 ±6.6 μm), middle vessels (resting diameter 21.1 ±7.9 μm) and large vessels (resting diameter 50.7 ±6.5 μm) to achieve 5% change of vascular dilation after stimulation was 1.5, 2 and 5.5 seconds, respectively. Approximately 5% peak change of relative blood flow (RBF) in both small and middle vessels was observed. The large vessels react slowly and their responses nearly 4 seconds delayed, but no significant change in RBF of the large vessels was seen.      

α-氯丙酸脱卤酶发酵动力学模型

对α-氯丙酸脱卤酶发酵动力学进行了研究。基于Logistic方程和Luedeking-Piret方程,得到了描述Pseudomonas W20菌发酵过程菌体生长、α-氯丙酸脱卤酶生成及基质消耗的动力学数学模型和模型参数,对试验数据与模型进行了验证比较,模型计算值与试验结果拟合良好,平均相对误差大部分小于10%;对脱卤酶反应动力学进行了研究,结果表明脱卤酶的脱卤反应基本符合米氏方程,并求得最大反应速率V_(max)=1.11×10~(-5)mol/(g·min),表观米氏常数K_m=3.72×10~(-3)mol/L。     

检测猪繁殖与呼吸综合征病毒RT-PCR的建立及应用

根据GenBank上PRRSV的保守序列,设计1对引物,建立了PRRSV的RT-PCR方法。试验结果表明,该RT-PCR方法敏感、特异,适于临床样品检测,为PRRSV的临床诊断和流行病学调查奠定了基础。     

重组人骨形成蛋白—3成熟肽的表达,纯化及诱骨活性的研究

推测人骨形成蛋白３羧基端的１２７氨基酸的肽段为其成熟肽（ｈＢＭＰ３ｍ）。将编码此成熟肽的ｃＤＮＡ插入含ＰＬ启动子的表达质粒ｐＤＨ中,构建表达质粒ｐＤＨＢ３ｍ,转化大肠杆菌ＤＨ５α。４２℃热诱导６ｈ后表达量达到最高水平,约占菌体总蛋白２８％;表达产物以包涵体形式存在。包涵体经分离和洗涤后,溶解于尿素,在变性溶解状态下经阳离子交换层析,目的蛋白纯度至少在９５％以上。再经稀释复性。然后将纯化、复性的重组人骨形成蛋白３成熟肽（ｒｈＢＭＰ３ｍ）植入小鼠肌肉间隙,于不同时间取材观察,在局部可见典型的软骨形成、软骨内成骨以及骨组织形成的过程,证实所制备的ｒｈＢＭＰ３ｍ具有明显的异位诱骨活性。     

氧化亚铁硫杆菌的分离及其培养条件优化

目的:获得可应用于烟气脱硫的菌株,并对其培养条件进行优化.方法:从化工厂取土样分离氧化亚铁硫杆菌,分析分离菌株的形态学特征、培养特征及16S rDNA序列,确定菌株的分类地位.通过单因子实验,对培养基中主要成分硫酸亚铁和硫酸铵的浓度进行优化.利用SAS软件中的Box-Behnken法设计实验,通过响应面分析对初始pH、温度、接种量、装液量4个因素进行优化.结果:获得菌株N16,经鉴定为嗜酸性氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans).确定FeSO_4·7H_2O和(NH_4)_2SO_4的最适添加量分别为60/L和1g/L.确定菌株最适培养条件为:初始pH 1.8,温度28℃,转速150r/min,接种量15%,装液量30mL.在最适培养墓及培养条件下,菌株N16的亚铁氧化率可达99.78%.结论:分离得到的菌株适合于微生物法烟气脱硫的应用.     

丽蝇蛹集金小蜂气味结合蛋白基因的克隆与序列分析

利用RACE技术,首次从丽蝇蛹集金小蜂Nasonia vitripennis中克隆获得一个气味结合蛋白全长cDNA序列.该基因全长553 bp,开放阅读框411 bp,3'和5'端非编码序列分别为13 bp和129 bp.其推导的氨基酸序列编码136个氨基酸,推测编码蛋白质的分子量为15.4 kDa,等电点为8.76.同源性比对分析发现,丽蝇蛹集金小蜂气味结合蛋白基因与现已报道的其它昆虫气味结合蛋白基因在氨基酸水平上的相似性均低于30%,拥有6个保守半胱氨酸位点等气味结合蛋白所具有的典型特征.系统进化树分析表明,丽蝇蛹集金小蜂气味结合蛋白与意大利蜜蜂Apis mellifera气味结合蛋白2,3,4,5,6,7,8和12聚为同一族,与意大利蜜蜂气味结合蛋白5,6和8的进化程度最近.RT-PCR分析表明,丽蝇蛹集金小蜂气味结合蛋白基因不仅在雌、雄成虫触角中高度表达,而且在头部和足中有微弱表达.     

簇生岐柄菌的超微形态学研究

为揭示网柄细胞状黏菌的超微结构特征,对簇生岐柄菌Cavendericfasciculata生活史过程中的孢子、黏变形体和柄细胞3种类型的细胞超微结构进行系统观察,并与目前仅知的3种网柄细胞状黏菌的超微结构进行比较.结果表明:簇生岐柄菌C.fasciculata的孢子、黏变形体和柄细胞内均有线粒体结构,随着细胞分化,线粒...     

KxVPO4F (x∼0): A New High-Voltage and Low-Stain Cathode Material for Ultrastable Calcium Rechargeable Batteries

The utilization of high-voltage intercalation cathodes in calcium-ion batteries (CIBs) is impeded by the substantial size and divalent character of Ca²⁺ ions, which result in pronounced volume alterations and sluggish ion mobility, consequently causing inferior reversibility and low energy/power densities. To tackle these issues, polyanionic K-vacant K_xVPO₄F (x∼0, designated as K₀VPF) is proposed as high-voltage and ultra-stable cathode material in CIBs. The K₀VPF demonstrates a decent calcium storage capacity of 75 mAh g⁻¹ at 10 mA g⁻¹ and remarkable capacity retention of 84.2% over 1000 cycles. The average working voltage of the K₀VPF is 3.85 V versus Ca²⁺/Ca, representing the highest value reported for CIB cathodes to date. The combined experimental and theoretical investigations revealed that the low volume changes and hopping diffusion barriers contribute to the extraordinary stability and high-power capabilities, respectively, of K₀VPF. The distribution of Ca ions into polyanionic frameworks with pronounced spatial separation effectively attenuates the Ca²⁺–Ca²⁺ repulsive force and thus augmenting the Ca migration kinetics. The high voltage of K₀VPF is attributed to the inductive effect from the largely electronegative fluorine. In conjunction with a calcium metal anode and a compatible electrolyte, Ca metal full cells featured a record-high energy density of ≈300 Wh kg⁻¹.