Identification of Multifaceted Binding Modes for Pyrin and ASC Pyrin Domains Gives Insights into Pyrin Inflammasome Assembly

Inflammasomes are macromolecular complexes that mediate inflammatory and cell death responses to pathogens and cellular stress signals. Dysregulated inflammasome activation is associated with autoinflammatory syndromes and several common diseases. During inflammasome assembly, oligomerized cytosolic pattern recognition receptors recruit procaspase-1 and procaspase-8 via the adaptor protein ASC. Inflammasome assembly is mediated by pyrin domains (PYDs) and caspase recruitment domains, which are protein interaction domains of the death fold superfamily. However, the molecular details of their interactions are poorly understood. We have studied the interaction between ASC and pyrin PYDs that mediates ASC recruitment to the pyrin inflammasome, which is implicated in the pathogenesis of familial Mediterranean fever. We demonstrate that both the ASC and pyrin PYDs have multifaceted binding modes, involving three sites on pyrin PYD and two sites on ASC PYD. Molecular docking of pyrin-ASC PYD complexes showed that pyrin PYD can simultaneously interact with up to three ASC PYDs. Furthermore, ASC PYD can self-associate and interact with pyrin, consistent with previous reports that pyrin promotes ASC clustering to form a proinflammatory complex. Finally, the effects of familial Mediterranean fever-associated mutations, R42W and A89T, on structural and functional properties of pyrin PYD were investigated. The R42W mutation had a significant effect on structure and increased stability. Although the R42W mutant exhibited reduced interaction with ASC, it also bound less to the pyrin B-box domain responsible for autoinhibition and hence may be constitutively active. Our data give new insights into the binding modes of PYDs and inflammasome architecture.     

Yellow fever vaccine: Comparison of the neurovirulence of new 17D-204 Stamaril™ seed lots and RK 168-73 strain

The neurovirulence of two new candidate 17D-204 Stamaril? working seed lots and that of two reference preparations were compared. The Stamaril? working seed lots have been used for more than twenty years for the manufacturing of vaccines of acceptable safety and efficacy. The preparation designated RK 168-73 and provided by the Robert Koch Institute was used as a reference. It was confirmed that RK 168-73 strain was not a good virus control in our study because it has a very low neurovirulence regarding both the clinical and histopathological scores in comparison with Stamaril? strain and is not representative of a vaccine known to be satisfactory in use. The results were reinforced by the phenotypic characterization by plaque assay demonstrating that RK 168-73 was very different from the Stamaril? vaccine, and by sequencing results showing 4 mutations between Stamaril? and RK 168-73 viruses leading to amino acid differences in the NS4B and envelop proteins.     

Neuropeptide FF receptor antagonist, RF9, attenuates the fever induced by central injection of LPS in mice

The endogenous opioid system has been found to be involved in the fever caused by lipopolysaccharide (LPS). Neuropeptide FF (NPFF, FLFQPQRF-NH₂) is an endogenous peptide known to modulate opioid activity, mainly in the central nervous system. Therefore, those data suggested a link between LPS-induced fever and NPFF systems. Using a model of acute neuroinflammation, we sought to determine the effects of NPFF systems on the fever induced by i.c.v. injection of LPS. Coinjected with different doses of NPFF (10 and 30 nmol), the fever of LPS (125 ng) was not modified. Interestingly, the selective NPFF receptors antagonist RF9 (30 nmol) injected into the third ventricle failed to induce significant effect, but it decreased the fever of LPS (125 ng) after cerebral administration in mice. These results suggest that NPFF receptors activation is required for LPS to produce fever. This interaction is the first evidence that NPFF systems participate in the control of acute neuroinflammation in conscious animals.     

The metabolic cost of fever in Pekin ducks

Fever is an energetically expensive component of the mammalian immune system’s acute phase response. Like mammals, birds also develop fever when exposed to pathogens, but, as yet, the energy requirements of febrile mediation in birds are not known. We injected ducks (Anas platyrhynchos; n=8) with 100 μ kg⁻¹ LPS or sterile isotonic saline and recorded their core body temperatures while measuring their O₂ consumption and CO₂ production in an open-flow respirometric circuit. Lipopolysaccharide elicited robust increases in the core body temperatures of our birds. The metabolic rate of the ducks increased about 80 min after treatment with LPS, relative to the metabolic rate of saline injected birds, and peaked 100 min later when the highest body temperatures were recorded. Our ducks increased their energy expenditure by 33.1% for about 3 h to mount a febrile response that, on average, increased their body temperature 1.4 °C. Studies with humans and rats, kept at thermoneutral temperatures, found a 10-15% increase in metabolic rate for every 1 °C increase in body temperature. The increase in metabolic rate, reported here (23%/°C), is noticeably higher and we conclude that febrile mediation is metabolically more expensive in Pekin ducks than in mammals.     

HFRSV在平皿表面室温暴露后存活力的定量研究

将肾综合症出血热病毒布于玻璃平皿表面,室温条件下分别暴露０、３０、６０、９０和１２０ｍｉｎ,观察病毒的定量存活情况。结果在经过１２０ｍｉｎ的暴露后,ＨＦＲＳＶ的效价仍高达１０４．２３ＴＣＩＤ５０。这一结果为ＨＦＲＳ的流行病学及其防治研究提供了重要的基础数据。     

Larvicidal effects of fungal Meroterpenoids in the control of Aedes aegypti L., the main vector of dengue and Yellow fever

The mosquito Aedes aegypti is an increasing problem of public health, being the vector responsible for dengue and Yellow Fever in tropical and subtropical regions. The aim of this work was to determine the potential larvicidal activity of a series of meroterpenoids, compounds 1-7, previously obtained fungal secondary metabolites from Penicillium sp., against the third-instar larvae of A. aegypti. The lethal concentrations (LC(50) and LC(90)) of 1-7 were evaluated 24 h after exposure. Dehydroaustin (4) was the most active meroterpenoid in the series, with an LC(50) value of 2.9 ppm, making it an attractive natural insecticide.     

中国和日本分离的几株流行性出血热病毒的抗原性比较

采用间接免疫荧光法(IFA)和ELISA法比较了几株中国和日本流行性出血热病毒(EHFV)的抗原性,IFA法不能区分大鼠属和姬鼠属来源的病毒,ELISA竞争试验表明,大鼠型病毒(R22、SR-11和TR-352株)与姬鼠型病毒(A 9株)存在弱单向交叉反应,交叉ELISA证实,A 9株与R22株、SR-11株和TR-352株均有较显著的抗原性差异,但R22,SR-11和TR-352株彼此间抗原性相近,本文讨论了有关EHFV抗原性比较中的一些问题。     

猪瘟和猪繁殖与呼吸综合征混合感染的快速检测及地域流行性分析

呼吸道和繁殖障碍疾病是猪场最常见的两种疾病,严重影响猪群的健康和正常生产,已经给世界养猪业造成了很大的经济损失。而且这两种疾病的病原复杂多样,不同的猪场病因可能完全不同,从而给疾病的诊断与防治带来了极大的困难。多年的研究表明,呼吸道和繁殖障碍疾病的病原包