Development of a preventive vaccine for Ebola virus infection in primates

Outbreaks of haemorrhagic fever caused by the Ebola virus are associated with high mortality rates that are a distinguishing feature of this human pathogen. The highest lethality is associated with the Zaire subtype, one of four strains identified to date. Its rapid progression allows little opportunity to develop natural immunity, and there is currently no effective anti-viral therapy. Therefore, vaccination offers a promising intervention to prevent infection and limit spread. Here we describe a highly effective vaccine strategy for Ebola virus infection in non-human primates. A combination of DNA immunization and boosting with adenoviral vectors that encode viral proteins generated cellular and humoral immunity in cynomolgus macaques. Challenge with a lethal dose of the highly pathogenic, wild-type, 1976 Mayinga strain of Ebola Zaire virus resulted in uniform infection in controls, who progressed to a moribund state and death in less than one week. In contrast, all vaccinated animals were asymptomatic for more than six months, with no detectable virus after the initial challenge. These findings demonstrate that it is possible to develop a preventive vaccine against Ebola virus infection in primates.     

Dll4 signalling through Notch1 regulates formation of tip cells during angiogenesis

In sprouting angiogenesis, specialized endothelial tip cells lead the outgrowth of blood-vessel sprouts towards gradients of vascular endothelial growth factor (VEGF)-A. VEGF-A is also essential for the induction of endothelial tip cells, but it is not known how single tip cells are selected to lead each vessel sprout, and how tip-cell numbers are determined. Here we present evidence that delta-like 4 (Dll4)-Notch1 signalling regulates the formation of appropriate numbers of tip cells to control vessel sprouting and branching in the mouse retina. We show that inhibition of Notch signalling using gamma-secretase inhibitors, genetic inactivation of one allele of the endothelial Notch ligand Dll4, or endothelial-specific genetic deletion of Notch1, all promote increased numbers of tip cells. Conversely, activation of Notch by a soluble jagged1 peptide leads to fewer tip cells and vessel branches. Dll4 and reporters of Notch signalling are distributed in a mosaic pattern among endothelial cells of actively sprouting retinal vessels. At this location, Notch1-deleted endothelial cells preferentially assume tip-cell characteristics. Together, our results suggest that Dll4-Notch1 signalling between the endothelial cells within the angiogenic sprout serves to restrict tip-cell formation in response to VEGF, thereby establishing the adequate ratio between tip and stalk cells required for correct sprouting and branching patterns. This model offers an explanation for the dose-dependency and haploinsufficiency of the Dll4 gene, and indicates that modulators of Dll4 or Notch signalling, such as gamma-secretase inhibitors developed for Alzheimer's disease, might find usage as pharmacological regulators of angiogenesis.     

A molecular information ratchet

Motor proteins and other biological machines are highly efficient at converting energy into directed motion and driving chemical systems away from thermodynamic equilibrium. But even though these biological structures have inspired the design of many molecules that mimic aspects of their behaviour, artificial nanomachine systems operate almost exclusively by moving towards thermodynamic equilibrium, not away from it. Here we show that information about the location of a macrocycle in a rotaxane-a molecular ring threaded onto a molecular axle-can be used, on the input of light energy, to alter the kinetics of the shuttling of the macrocycle between two compartments on the axle. For an ensemble of such molecular machines, the macrocycle distribution is directionally driven away from its equilibrium value without ever changing the relative binding affinities of the ring for the different parts of the axle. The selective transport of particles between two compartments by brownian motion in this way bears similarities to the hypothetical task performed without an energy input by a 'demon' in Maxwell's famous thought experiment. Our observations demonstrate that synthetic molecular machines can operate by an information ratchet mechanism, in which knowledge of a particle's position is used to control its transport away from equilibrium.     

小鼠胚胎干细胞对病毒性心肌炎的影响

目的使用小鼠验证这样一个假设:外界病毒浸入诱发心肌炎时,机体的干细胞将进入心脏提高心肌的抗病毒能力。方法雄性BALB/c小鼠分为三组:小鼠胚胎干细胞对照组(ES),心肌炎病毒组(EM CV)及EM-CV加ES治疗组。通过尾静脉注射,令小鼠立即感染病毒。小鼠死亡率,炎性细胞浸润及心肌坏死等为观察指征。干细胞的游走及分化等通过免疫荧光法来验证。结果给予干细胞后的小鼠的存活率明显高于生理盐水对照组,炎性细胞侵润及心肌坏死亦明显低于生理盐水对照组。免疫荧光法表明,干细胞进入心肌并分化成新的心肌细胞。结论干细胞能明显提高心肌炎小鼠的存活率,减少心肌组织的坏死。同时,亦证明当心脏遭受病毒的侵入后,干细胞通过某种机理修复或再生心肌细胞,从而提高组织的抗病毒能力。     

Common genetic variants at the CRAC1 (HMPS) locus on chromosome 15q13.3 influence colorectal cancer risk

We mapped a high-penetrance gene (CRAC1; also known as HMPS) associated with colorectal cancer (CRC) in the Ashkenazi population to a 0.6-Mb region on chromosome 15 containing SCG5 (also known as SGNE1), GREM1 and FMN1. We hypothesized that the CRAC1 locus harbored low-penetrance variants that increased CRC risk in the general population. In a large series of colorectal cancer cases and controls, SNPs near GREM1 and SCG5 were strongly associated with increased CRC risk (for rs4779584, P = 4.44 x 10(-14)).     

Genome-wide association scan of tag SNPs identifies a susceptibility locus for lung cancer at 15q25.1

To identify risk variants for lung cancer, we conducted a multistage genome-wide association study. In the discovery phase, we analyzed 315,450 tagging SNPs in 1,154 current and former (ever) smoking cases of European ancestry and 1,137 frequency-matched, ever-smoking controls from Houston, Texas. For replication, we evaluated the ten SNPs most significantly associated with lung cancer in an additional 711 cases and 632 controls from Texas and 2,013 cases and 3,062 controls from the UK. Two SNPs, rs1051730 and rs8034191, mapping to a region of strong linkage disequilibrium within 15q25.1 containing PSMA4 and the nicotinic acetylcholine receptor subunit genes CHRNA3 and CHRNA5, were significantly associated with risk in both replication sets. Combined analysis yielded odds ratios of 1.32 (P < 1 x 10(-17)) for both SNPs. Haplotype analysis was consistent with there being a single risk variant in this region. We conclude that variation in a region of 15q25.1 containing nicotinic acetylcholine receptors genes contributes to lung cancer risk.     

施加岩粉对水稻生态系统植硅体碳的增汇作用(英文)

植硅体态碳(Phyt OC)在植硅体的"保护"作用下,可以长时间地保存在土壤中,是一种长期有效的生物固碳机制.本文通过在盆栽水稻中施加不同水平的岩粉来探讨其对植硅体态碳增汇的影响.通过微波消解法提取植硅体和氢氟酸溶解生物硅测定其植硅体封存的碳含量.结果表明,施加岩粉显著地提高了水稻各器官中植硅体和植硅体态碳含量及其植硅体碳的产生通量.因此,硅营养调控机制(外施硅肥)是一种提高农田生态系统(尤其是稻田)植硅体封存有机碳的潜力、增加土壤中Phyt OC积累速率的有效措施.     

Does vagal stimulation liberate secretin and/or cholecystokinin in pigs?

Zusammenfassung Beim Schwein wird mittels Parameter des Pankreas nachgewiesen, dass Sekretin- oder auch Cholecystokinin-Sekretion vom Vagus reguliert wird.

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Supported by funds from National Science Foundation, Industria Distillers, and Veterans Administration Hospital, Omaha, Nebraska, USA.

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Acknowledgement: We are grateful for the help of R. Pfahler, G. Rice and R. Williams.