豚鼠耳蜗中ATP对一氧化氮/环磷酸鸟苷途径的激活作用

实验研究了豚鼠耳蜗中ATP和一氧化氮／环磷酸鸟苷途径(nitric oxide／cyclic guanosine monophosphate,NO／cGMP pathway)的关系。将40只耳廓反射灵敏的健康白色豚鼠随机分为5组,分别对其离体的耳蜗即刻灌流人工外淋巴基础液(artificial perilymph basic solution,APBS)以及溶于人工外淋巴基础液的ATP、一氧化氮合酶抑制剂左旋-N^G-硝基精氨酸(L-N^G-nitroarginine,L-NNA) ATP、可溶性鸟苷酸环化酶抑制剂1H-[1,2,4]草酸重氮[4,3-a]喹恶啉(1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one,ODQ) ATP和A-23187(Ca^2 载体),收集耳蜗组织标本,利用放射免疫方法测定耳蜗组织中的cGMP的平均含量,比较各组之间耳蜗组织cGMF平均含量的差异。试验结果显示,向刚离体的耳蜗中灌流ATP和A-23187可以引起耳蜗组织中的cGMP含量升高,而灌流L-NNA和ODQ则可以抑制ATP所引起的耳蜗组织中cGMP含量的升高,提示在耳蜗组织中ATP可以通过升高细胞内Ca^2 浓度的作用而激活NO／cGMF途径。从本实验结果可以提出假说：耳蜗中ATP从神经末梢释放,通过提高细胞内Ca^2 的浓度,有激活NO／cGMP途径的作用,而NO／cGMP又能对ATP进行负反馈调节,两者共同调节耳蜗的生理功能,在耳蜗中存在ATP／Ca^2 -NO／cGMP通路。     

Granulation of activated sludge in a continuous flow airlift reactor by strong drag force

Most aerobic granule cultivation has been based on the sequencing batch reactor (SBR) and then the factors that affect aerobic granulations were developed in the SBR. However, little work has been done to cultivate aerobic granules in a continuous-flow bioreactor with simple structure that is realistic for engineering. This work is the first to cultivate aerobic granules in a continuous flow airlift fluidized bed reactor (CAFB) possesses a very simple structure and without settling time and starvation time controlling. The configuration of CAFB was the simplest continuous-flow aerobic granular bioreactor reported by now. The majority of granules could be formatted in the CAFB after 12 days cultivation. The effluent COD concentration maintained at 50 ± 10 mg/L for the variable COD loading rate of 3.5 g COD/L/d and 4.8 g COD/L/d, which confirmed that the CAFB performed good anti-shock abilities. CAFB performed good nitrification ability, however, little denitrification was found under the operating conditions of this study. The shear stress acting on the solid phase were hundreds of times stronger in the CAFB than in the SBR at the same aeration strength. It seems CAFB is very efficient for granulation due to the strong shear-force exertion, which is promising for continuous-flow aerobic granular bioreactor. Protein, positive to the hydrophobicity, was predominant in extracellular polymeric substances in the granules, and favored the granules formation in the CAFB combined with the polysaccharides. However, filamentous bulking always happened in 35 days operation of the CAFB, thus further study on the stability of this bioreactor is urgently necessary.     

Whole‐brain microcirculation detection after ischemic stroke based on swept‐source optical coherence tomography

The occurrence and development of ischemic stroke are closely related to cerebral blood flow. Real‐time monitoring of cerebral perfusion level is very useful for understanding the mechanisms of the disease. A wide field of view (FOV) is conducive to capturing lesions and observing the progression of the disease. In this paper, we attempt to monitor the whole‐brain microcirculation in middle cerebral artery occlusion (MCAO) rats over time using a wide FOV swept‐source OCT (SS‐OCT) system. A constrained image registration algorithm is used to remove motion artifacts that are prone to occur in a wide FOV angiography. During ischemia, cerebral perfusion levels in the left and right hemispheres, as well as in the whole brain were quantified and compared. Changes in the shape and location of blood vessels were also recorded. The results showed that the trend in cerebral perfusion levels of both hemispheres was highly consistent during MCAO, and the position of the blood vessels varied over time. This work will provide new insights of ischemic stroke and is helpful to assess the effectiveness of potential treatment strategies.      

不同氮源对球形棕囊藻生长的影响

采用实验室培养的方法比较了6种不同氮源-硝态氮、尿素、甘氨酸、精氨酸、谷氨酸、腺嘌呤对典型赤潮藻球形棕囊藻(Phaeocystis globosa)生长的影响。结果表明,6种氮源均能不同程度地促进球形棕囊藻的生长,但比生长速率和光合作用效率具有显著差异性。将球形棕囊藻在不同浓度氮源下的最大比生长速率分别拟合Monod方程,得出球形棕囊藻在硝态氮、尿素、甘氨酸、精氨酸、谷氨酸和腺嘌呤等6种氮源下的最大比生长率分别为1.05,1.17,0.82,0.87,1.09,0.90d^-1,相应的半饱和常数分别为9.132,23.758,85.519,7.104,23.94,10.959μmol/L。其中,高氮浓度(8820μmol/L)下腺嘌呤对球型棕囊藻的生长具有显著抑制作用。相比较而言,球形棕囊藻对甘氨酸的亲和力最高。当硝态氮、尿素、甘氨酸、精氨酸、谷氨酸和腺嘌呤的浓度分别为8820,882,882,8820,882,0.441μmol/L时,球形棕囊藻的最大光合效率(Fv/Fm)分别为0.619,0.620,0.579,0.595,0.648,0.667。由此可见,氮源对球形棕囊藻的生长和光合作用具有显著影响;球形棕囊藻能够利用多种无机和有机氮源,与其它仅能利用无机氮源的浮游植物相比,更具有竞争优势。     

Reconstruction of Ancestral Gene Orders Using Probabilistic and Gene Encoding Approaches

Current tools used in the reconstruction of ancestral gene orders often fall into event-based and adjacency-based methods according to the principles they follow. Event-based methods such as GRAPPA are very accurate but with extremely high complexity, while more recent methods based on gene adjacencies such as InferCARsPro is relatively faster, but often produces an excessive number of chromosomes. This issue is mitigated by newer methods such as GapAdj, however it sacrifices a considerable portion of accuracy. We recently developed an adjacency-based method in the probabilistic framework called PMAG to infer ancestral gene orders. PMAG relies on calculating the conditional probabilities of gene adjacencies that are found in the leaf genomes using the Bayes'' theorem. It uses a novel transition model which accounts for adjacency changes along the tree branches as well as a re-rooting procedure to prevent any information loss. In this paper, we improved PMAG with a new method to assemble gene adjacencies into valid gene orders, using an exact solver for traveling salesman problem (TSP) to maximize the overall conditional probabilities. We conducted a series of simulation experiments using a wide range of configurations. The first set of experiments was to verify the effectiveness of our strategy of using the better transition model and re-rooting the tree under the targeted ancestral genome. PMAG was then thoroughly compared in terms of three measurements with its four major competitors including InferCARsPro, GapAdj, GASTS and SCJ in order to assess their performances. According to the results, PMAG demonstrates superior performance in terms of adjacency, distance and assembly accuracies, and yet achieves comparable running time, even all TSP instances were solved exactly. PMAG is available for free at http://phylo.cse.sc.edu.     

RETRACTED ARTICLE: Silencing SP1 Alleviated Sevoflurane-Induced POCD Development via Cholinergic Anti-inflammatory Pathway

Neurochemical Research - Postoperative cognitive dysfunction (POCD) is a common complication induced by anesthesia or surgery, which affects the concentration, cognition and memory of patients....