Relative Sensitivities of Viruses to Different Species of Interferon

Some viruses were found to be more sensitive than others to the action of interferons from certain species of animals but less sensitive to interferons from other species. Vaccinia virus was the most sensitive to mouse and hamster interferons of five viruses tested, but the least sensitive of these five viruses to human, rabbit, and bat interferons. The relative sensitivities of the viruses to interferons were found to be characteristic for each of the species tested, with those closely related phylogenetically exhibiting similar patterns of relative interferon-induced virus resistance. The amount of synthetic double-stranded polynucleotide polyinosinic acid-polycytidylic acid required to induce resistance to each of the viruses in each of the cell species correlated with the interferon sensitivities of the viruses.     

Intracellular Production of Brucella L Forms I. Recovery of L Forms from Tissue Culture Cells Infected with Brucella abortus

Hatten, Betty A. (The University of Texas Southwestern Medical School, Dallas), and S. Edward Sulkin. Intracellular production of Brucella L forms. I. Recovery of L forms from tissue culture cells infected with Brucella abortus. J. Bacteriol. 91:285-296. 1966.-Infectivity of virulent Brucella abortus strain 3183 was less for hamster macrophages after a 2-hr adsorption period than for an attenuated strain (S19) and its tissue culture variant (30). Both strains S19 and 30 were very toxic for the cells, but 3183 was not toxic. Two types of L forms were recovered from a large percentage of hamster kidney cell cultures when disintegration of infected cells was accelerated by tissue culture medium of high pH. One type grew in finely granular microcolonies, was isolated from cells infected for short periods of time, and often reverted to the bacterial form. The other type occurred in small irregularly shaped forms which later developed into round bodies. Both stained specifically with fluorescein-conjugated B. abortus antiserum. Semisolid media containing 0.7% agar provided optimal subsurface L-form growth. L forms also grew well in Thioglycollate Medium but grew poorly in other liquid media. Surface L-form growth was supported by several agar media, but CO(2) was required for optimal growth. Monolayers infected with strain 3183 and examined immediately after adsorption contained occasional small, round bodies. Bizarre forms increased in number with time and, after 24 to 72 hr, large pink-staining inclusions were often present which persisted for several days. Also appearing at about the same time were smaller, dark-staining forms which were first seen in clusters but later dispersed and finally occurred in chainlike configurations. Direct fluorescent-antibody stains of infected cells established that the intracellular forms were related to the infecting strain of B. abortus.     

Optical Mapping of Action Potentials and Calcium Transients in the Mouse Heart

The mouse heart is a popular model for cardiovascular studies due to the existence of low cost technology for genetic engineering in this species. Cardiovascular physiological phenotyping of the mouse heart can be easily done using fluorescence imaging employing various probes for transmembrane potential (V_m), calcium transients (CaT), and other parameters. Excitation-contraction coupling is characterized by action potential and intracellular calcium dynamics; therefore, it is critically important to map both V_m and CaT simultaneously from the same location on the heart^1-4. Simultaneous optical mapping from Langendorff perfused mouse hearts has the potential to elucidate mechanisms underlying heart failure, arrhythmias, metabolic disease, and other heart diseases. Visualization of activation, conduction velocity, action potential duration, and other parameters at a myriad of sites cannot be achieved from cellular level investigation but is well solved by optical mapping^1,5,6. In this paper we present the instrumentation setup and experimental conditions for simultaneous optical mapping of V_m and CaT in mouse hearts with high spatio-temporal resolution using state-of-the-art CMOS imaging technology. Consistent optical recordings obtained with this method illustrate that simultaneous optical mapping of Langendorff perfused mouse hearts is both feasible and reliable.     

Homology modeling, simulation and molecular docking studies of catechol-2, 3-Dioxygenase from Burkholderia cepacia: Involved in degradation of Petroleum hydrocarbons

Catechol 2, 3-dioxygenase is present in several types of bacteria and undergoes degradation of environmental pollutants through an important key biochemical pathways. Specifically, this enzyme cleaves aromatic rings of several environmental pollutants such as toluene, xylene, naphthalene and biphenyl derivatives. Hence, the importance of Catechol 2, 3-dioxygenase and its role in the degradation of environmental pollutants made us to predict the three-dimensional structure of Catechol 2, 3-dioxygenase from Burkholderia cepacia. The 10ns molecular dynamics simulation was carried out to check the stability of the modeled Catechol 2, 3- dioxygenase. The results show that the model was energetically stable, and it attains their equilibrium within 2000 ps of production MD run. The docking of various petroleum hydrocarbons into the Catechol 2,3-dioxygenase reveals that the benzene, O-xylene, Toluene, Fluorene, Naphthalene, Carbazol, Pyrene, Dibenzothiophene, Anthracene, Phenanthrene, Biphenyl makes strong hydrogen bond and Van der waals interaction with the active site residues of H150, L152, W198, H206, H220, H252, I254, T255, Y261, E271, L276 and F309. Free energy of binding and estimated inhibition constant of these compounds demonstrates that they are energetically stable in their binding cavity. Chrysene shows positive energy of binding in the active site atom of Fe. Except Pyrene all the substrates made close contact with Fe atom by the distance ranges from 1.67 to 2.43 Å. In addition to that, the above mentioned substrate except pyrene all other made π-π stacking interaction with H252 by the distance ranges from 3.40 to 3.90 Å. All these docking results reveal that, except Chrysene all other substrate has good free energy of binding to hold enough in the active site and makes strong VdW interaction with Catechol-2,3-dioxygenase. These results suggest that, the enzyme is capable of catalyzing the above-mentioned substrate.     

藏药七十味珍珠丸改善APP/PS1小鼠学习记忆能力

藏药七十味珍珠丸（ratanasampil,RNSP）可改善大脑氧化应激水平,改善大脑功能,有安神和促进学习记忆的功效,然而RNSP是否可改善阿尔茨海默症（AD）小鼠的学习记忆功能,尚缺乏系统研究。本研究采用APP/PS 1转基因小鼠为研究对象,并随机将其分为实验组和对照组。对实验组进行为期12周的RNSP灌胃给药,对照组进行12周的蒸馏水灌胃,采用Morris水迷宫与开场实验评价小鼠学习记忆能力,比较小鼠体重与相关器官质量,并比较器官质量指数,通过分子生物学检测指标评价小鼠脑内老年斑数量,Aβ生成量及BACE1表达水平。本研究证实,与对照组相比,给药组小鼠定位航行潜伏期明显缩短（22.60±13.26 vs. 46.44±8.41, P<0.01, day 5）,穿越平台次数明显增加（1.29±0.37 vs. 0.54±0.29, P<0.01）,探洞次数明显增加（32.11±9.85 vs. 20.89±8.78, P<0.05）,表明RNSP提高了APP/PS 1小鼠的学习记忆能力和空间探索能力。与对照组相比,给药组小鼠大脑重量及脑质量指数均增高（0.4135±0.0102 vs. 0.3833±0.0254, P<0.05;2.04±0.08 vs. 1.84±0.15, P<0.05）,脑内老年斑数量减少（18.70±7.88 vs. 38.83±6.15, P<0.05）,Aβ1- 42水平及BACE1表达均显著降低（0.19±0.08 vs. 0.41±0.12, P<0.05; 0.136±0.04 vs. 0.206±0.02, P<0.05）,表明RNSP延缓了APP/PS 1小鼠的脑萎缩进程,降低脑内老年斑的形成,下调脑内Aβ1-42水平和BACE1裂解酶的蛋白质表达量。本研究提示,RNSP可改善APP/PS 1小鼠的学习记忆能力,其机制可能和RNSP抑制脑萎缩,降低BACE1蛋白表达以及减少脑内Aβ沉积有关。     

甘肃盐池湾黑颈鹤亚成体夏季生境选择

开展对亚成体的研究,可以更加全面了解一个物种,进而更有效地开展保护工作。甘肃盐池湾国家级自然保护区是黑颈鹤（Grus nigricollis）成体的重要繁殖地和亚成体的重要栖息地之一。为研究甘肃盐池湾黑颈鹤亚成体生境选择,于2020年7月初至8月中旬在盐池湾党河湿地展开调查,并依据Johnson对生境选择空间尺度的划分,对亚成体活动区内各类型生境和觅食微生境的生境选择进行了研究。通过遥感影像解译和卫星跟踪分别获得各栖息地类型面积以及黑颈鹤的活动位点,利用核密度分析法估计活动区面积并利用Manly研究中的设计Ⅲ来研究活动区内各类型生境选择;通过选取利用样方和对照样方,使用χ2检验、独立样本t检验和Mann-Whitney U检验,对比检验样方数据,进行微生境选择的研究。结果表明,活动区内各类型生境中亚成体选择河流,拒绝戈壁和沼泽化草甸,对沼泽既不选择也不拒绝,而成体选择湖泊,没有利用河流,同时拒绝戈壁、山脉、沼泽化草甸和盐化草甸,对沼泽既不选择也不拒绝;觅食微生境选择中,亚成体选择平均植被盖度为57.07% ± 4.53%,基质类型为泥炭,基质硬度为中,主要植被黑褐苔草（Carex atrofusca）的微生境栖息,相比成体,亚成体选择的生境基质更硬,距道路距离更近,距房屋、河流、山脉和湖泊距离更远。亚成体的栖息地选择主要受到生境质量、生境资源有限性以及成体选择等因素的影响。在这些因素的影响下,亚成体与成体产生了生态位分离,并在栖息地选择上出现了分化。这种分化对亚成体的生存和成体的繁殖都有益,可以避免种内无效的冲突和竞争,有利于亚成体和成体的适合度增加。保护黑颈鹤的栖息环境需同时考虑到亚成体的选择和生存。     

Local and systemic effects of two herbivores with different feeding mechanisms on primary metabolism of cotton leaves

Caterpillars and spider mites are herbivores with different feeding mechanisms. Spider mites feed on the cell content via stylets, while caterpillars, as chewing herbivores, remove larger amounts of photosynthetically active tissue. We investigated local and systemic effects of short-term caterpillar and spider mite herbivory on cotton in terms of primary metabolism and growth processes. After short-term caterpillar feeding, leaf growth and water content were decreased in damaged leaves. The glutamate/glutamine ratio increased and other free amino acids were also affected. In contrast, mild spider mite infestation did not affect leaf growth or amino acid composition, but led to an increase in total nitrogen and sucrose concentrations. Both herbivores induced locally increased dark respiration, suggesting an increased mobilization of storage compounds potentially available for synthesis of defensive substances, but did not affect assimilation and transpiration. Systemically induced leaves were not significantly affected by the treatments performed in this study. The results show that cotton plants do not compensate the loss of photosynthetic tissue with higher photosynthetic efficiency of the remaining tissue. However, early plant responses to different herbivores leave their signature in primary metabolism, affecting leaf growth. Changes in amino acid concentrations, total nitrogen and sucrose content may affect subsequent herbivore performance.