Thraustochytrid Aurantiochytrium sp. 18W-13a accummulates high amounts of squalene

Here we report on the 18W-13a strain of Aurantiochytrium sp., which accumulates very high amounts of squalene. The squalene contents and production at 4 d of culture were 198 mg/g and 1.29 ± 0.13 g/L, respectively, exceptionally high values compared to previous reports.     

BAG3 mediates chaperone-based aggresome-targeting and selective autophagy of misfolded proteins

Increasing evidence indicates the existence of selective autophagy pathways, but the manner in which substrates are recognized and targeted to the autophagy system is poorly understood. One strategy is transport of a particular substrate to the aggresome, a perinuclear compartment with high autophagic activity. In this paper, we identify a new cellular pathway that uses the specificity of heat-shock protein 70 (Hsp70) to misfolded proteins as the basis for aggresome-targeting and autophagic degradation. This pathway is regulated by the stress-induced co-chaperone Bcl-2-associated athanogene 3 (BAG3), which interacts with the microtubule-motor dynein and selectively directs Hsp70 substrates to the motor and thereby to the aggresome. Notably, aggresome-targeting by BAG3 is distinct from previously described mechanisms, as it does not depend on substrate ubiquitination.     

The effects on immune response of levamisole treatment following infection of U-937 macrophages with Candida albicans

The aim of this study was to investigate the effects on the immune response of levamisole alone and in conjunction with Candida albicans stimulation in human macrophage cell culture by determining the alterations in the levels of cytokine release. Levamisole treatment was performed before, during and after infecting U-937 human macrophage cells with C. albicans. In cell supernatants, interleukin (IL)-1b, IL-12, IL-18, tumour necrosis factor alpha (TNF-α) levels were measured by ELISA. In vitro levamisole treatment accompanied by C. albicans stimulation significantly increased IL-12, IL-1β and IL-18 production in macrophage cells (p < 0.05). It was observed that when administered before C. albicans infection, levamisole significantly increased IL-12 and IL-1β production in macrophage cells (p < 0.05). Another finding was that when applied to macrophage cells simultaneously with C. albicans infection, or before infection with C. albicans, levamisole suppressed the TNF-β production stimulating effect of C. albicans (p < 0.05). These results indicated that levamisole could be useful in treating patients infected with C. albicans or in protecting individuals under the risk of being infected with this pathogen. There is a need for further experimental and clinical studies on this hypothesis.     

Cryo-electron tomography: The challenge of doing structural biology in situ

The mitotic segregation apparatus composed of microtubules and chromatin functions to faithfully partition a duplicated genome into two daughter cells. Microtubules exert extensional pulling force on sister chromatids toward opposite poles, whereas pericentric chromatin resists with contractile springlike properties. Tension generated from these opposing forces silences the spindle checkpoint to ensure accurate chromosome segregation. It is unknown how the cell senses tension across multiple microtubule attachment sites, considering the stochastic dynamics of microtubule growth and shortening. In budding yeast, there is one microtubule attachment site per chromosome. By labeling several chromosomes, we find that pericentromeres display coordinated motion and stretching in metaphase. The pericentromeres of different chromosomes exhibit physical linkage dependent on centromere function and structural maintenance of chromosomes complexes. Coordinated motion is dependent on condensin and the kinesin motor Cin8, whereas coordinated stretching is dependent on pericentric cohesin and Cin8. Linking of pericentric chromatin through cohesin, condensin, and kinetochore microtubules functions to coordinate dynamics across multiple attachment sites.     

Viral information

Viruses are major drivers of global biogeochemistry and the etiological agents of many diseases. They are also the winners in the game of life: there are more viruses on the planet than cellular organisms and they encode most of the genetic diversity on the planet. In fact, it is reasonable to view life as a viral incubator. Nevertheless, most ecological and evolutionary theories were developed, and continue to be developed, without considering the virosphere. This means these theories need to be to reinterpreted in light of viral knowledge or we need to develop new theory from the viral point-of-view. Here we briefly introduce our viral planet and then address a major outstanding question in biology: why is most of life viral? A key insight is that during an infection cycle the original virus is completely broken down and only the associated information is passed on to the next generation. This is different for cellular organisms, which must pass on some physical part of themselves from generation to generation. Based on this premise, it is proposed that the thermodynamic consequences of physical information (e.g., Landauer’s principle) are observed in natural viral populations. This link between physical and genetic information is then used to develop the Viral Information Hypothesis, which states that genetic information replicates itself to the detriment of system energy efficiency (i.e., is viral in nature). Finally, we show how viral information can be tested, and illustrate how this novel view can explain existing ecological and evolutionary theories from more fundamental principles.     

Investigation of the mechanism of nicotine-induced relaxation on the sheep sphincter of Oddi

Possible mechanisms for nicotine-induced relaxation were investigated in the isolated sheep's sphincter of Oddi. Sheep's sphincter of Oddi rings were mounted in tissue bath with modified Krebs-Henseleit solution and aerated with 95% oxygen and 5% carbon dioxide. Tension was measured with isometric force transducers, and muscle relaxation was expressed as percent decrease of precontraction induced by carbachol. Nicotine (1 x 10(-5) to 3 x 10(-3) mol/L) produced concentration-dependent relaxation on sphincter of Oddi precontracted by carbachol (10(-6) mol/L). Nicotine-induced relaxation was 72.8 +/- 4.2% of precontraction with carbachol (10(-6) mol/L) (mean pD2 value, 3.76 +/- 0.05 mol/L). Nicotine-induced relaxation was not affected by N(w)-nitro L-arginine methyl ester (L-NAME) (3 x 10(-5) mol/L), methylene blue (10(-5) mol/L), indomethacin (10(-5) mol/L), hexamethonium (10(-5) mol/L), glibenclamide (10(-5) mol/L), 4-aminopyridine (10(-3) mol/L), tetraethylammonium (3 x 10(-4) mol/L), clotrimazole (10(-6) mol/L), 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) (10(-6) mol/L), and anthracene-9-carboxylate (9-AC) (10(-6) mol/L), but potentiated by bupivacain (10(-5) mol/L). A calcium-antagonizing effect of nicotine was not observed. The results suggest that nicotine-induced relaxation of the sheep's sphincter of Oddi is not mediated by the release of prostaglandins, nitric oxide (NO), or a related substance; by the activation of potassium channels or chloride channels; or by the stimulation of nicotinic cholinoceptors. Potentiation of the nicotine-induced relaxation by bupivacain indicates that blockade of sodium channels may play a role in this relaxation.     

密云古石峪封山育林试验方法

要加速北京地区的绿化,除造林外,封山育林是一种有效办法。本次试验的目的就是探讨一个封山育林试验方法,寻找检查封育效果的指标。本次试验设置样地6组,12块,分别测定了环境因子、母树条件、土壤水分、植被盖度,多样性指数和生物量。通过对各测定因子进行横向(类型)和纵向(历史)的比较看出：(1)影响封育效果的主要是坡向,坡向与水分条件密切相关,其它因子也与水分相关;(2)灌木、草木植物的盖度和生物量经封山育林后有所提高。所以草、灌的盖度、牛物量等的变化可作为乔木更新前封育效果的指标。