56 research outputs found
Automatic classification of spectra from the Infrared Astronomical Satellite (IRAS)
A new classification of Infrared spectra collected by the Infrared Astronomical Satellite (IRAS) is presented. The spectral classes were discovered automatically by a program called Auto Class 2. This program is a method for discovering (inducing) classes from a data base, utilizing a Bayesian probability approach. These classes can be used to give insight into the patterns that occur in the particular domain, in this case, infrared astronomical spectroscopy. The classified spectra are the entire Low Resolution Spectra (LRS) Atlas of 5,425 sources. There are seventy-seven classes in this classification and these in turn were meta-classified to produce nine meta-classes. The classification is presented as spectral plots, IRAS color-color plots, galactic distribution plots and class commentaries. Cross-reference tables, listing the sources by IRAS name and by Auto Class class, are also given. These classes show some of the well known classes, such as the black-body class, and silicate emission classes, but many other classes were unsuspected, while others show important subtle differences within the well known classes
Gene copy number variation throughout the Plasmodium falciparum genome
BACKGROUND: Gene copy number variation (CNV) is responsible for several important phenotypes of the malaria parasite Plasmodium falciparum, including drug resistance, loss of infected erythrocyte cytoadherence and alteration of receptor usage for erythrocyte invasion. Despite the known effects of CNV, little is known about its extent throughout the genome. RESULTS: We performed a whole-genome survey of CNV genes in P. falciparum using comparative genome hybridisation of a diverse set of 16 laboratory culture-adapted isolates to a custom designed high density Affymetrix GeneChip array. Overall, 186 genes showed hybridisation signals consistent with deletion or amplification in one or more isolate. There is a strong association of CNV with gene length, genomic location, and low orthology to genes in other Plasmodium species. Sub-telomeric regions of all chromosomes are strongly associated with CNV genes independent from members of previously described multigene families. However, approximately 40% of CNV genes were located in more central regions of the chromosomes. Among the previously undescribed CNV genes, several that are of potential phenotypic relevance are identified. CONCLUSION: CNV represents a major form of genetic variation within the P. falciparum genome; the distribution of gene features indicates the involvement of highly non-random mutational and selective processes. Additional studies should be directed at examining CNV in natural parasite populations to extend conclusions to clinical settings
Memory CD8<sup>+</sup> T cells exhibit tissue imprinting and non-stable exposure-dependent reactivation characteristics following blood-stage Plasmodium berghei ANKA infections
Experimental cerebral malaria (ECM) is a severe complication of Plasmodium berghei ANKA (PbA) infection in mice, characterized by CD8(+) Tâcell accumulation within the brain. Whilst the dynamics of CD8(+) Tâcell activation and migration during extant primary PbA infection have been extensively researched, the fate of the parasiteâspecific CD8(+) T cells upon resolution of ECM is not understood. In this study, we show that memory OTâI cells persist systemically within the spleen, lung and brain following recovery from ECM after primary PbAâOVA infection. Whereas memory OTâI cells within the spleen and lung exhibited canonical central memory (Tcm) and effector memory (Tem) phenotypes, respectively, memory OTâI cells within the brain postâPbAâOVA infection displayed an enriched CD69(+)CD103(â) profile and expressed low levels of Tâbet. OTâI cells within the brain were excluded from shortâterm intravascular antibody labelling but were targeted effectively by longerâterm systemically administered antibodies. Thus, the memory OTâI cells were extravascular within the brain postâECM but were potentially not resident memory cells. Importantly, whilst memory OTâI cells exhibited strong reactivation during secondary PbAâOVA infection, preventing activation of new primary effector T cells, they had dampened reactivation during a fourth PbAâOVA infection. Overall, our results demonstrate that memory CD8(+) T cells are systemically distributed but exhibit a unique phenotype within the brain postâECM, and that their reactivation characteristics are shaped by infection history. Our results raise important questions regarding the role of distinct memory CD8(+) Tâcell populations within the brain and other tissues during repeat Plasmodium infections
Roles for the Conserved Spc105p/Kre28p Complex in Kinetochore-Microtubule Binding and the Spindle Assembly Checkpoint
Kinetochores attach sister chromatids to microtubules of the mitotic spindle and orchestrate chromosome disjunction at anaphase. Although S. cerevisiae has the simplest known kinetochores, they nonetheless contain approximately 70 subunits that assemble on centromeric DNA in a hierarchical manner. Developing an accurate picture of the DNA-binding, linker and microtubule-binding layers of kinetochores, including the functions of individual proteins in these layers, is a key challenge in the field of yeast chromosome segregation. Moreover, comparison of orthologous proteins in yeast and humans promises to extend insight obtained from the study of simple fungal kinetochores to complex animal cell kinetochores.We show that S. cerevisiae Spc105p forms a heterotrimeric complex with Kre28p, the likely orthologue of the metazoan kinetochore protein Zwint-1. Through systematic analysis of interdependencies among kinetochore complexes, focused on Spc105p/Kre28p, we develop a comprehensive picture of the assembly hierarchy of budding yeast kinetochores. We find Spc105p/Kre28p to comprise the third linker complex that, along with the Ndc80 and MIND linker complexes, is responsible for bridging between centromeric heterochromatin and kinetochore MAPs and motors. Like the Ndc80 complex, Spc105p/Kre28p is also essential for kinetochore binding by components of the spindle assembly checkpoint. Moreover, these functions are conserved in human cells.Spc105p/Kre28p is the last of the core linker complexes to be analyzed in yeast and we show it to be required for kinetochore binding by a discrete subset of kMAPs (Bim1p, Bik1p, Slk19p) and motors (Cin8p, Kar3p), all of which are nonessential. Strikingly, dissociation of these proteins from kinetochores prevents bipolar attachment, even though the Ndc80 and DASH complexes, the two best-studied kMAPs, are still present. The failure of Spc105 deficient kinetochores to bind correctly to spindle microtubules and to recruit checkpoint proteins in yeast and human cells explains the observed severity of missegregation phenotypes
Design and development of a direct injection system for cryogenic engines
The cryogenic engine has received increasing attention due to its promising potential as a zero-emission engine. In this study, a new robust liquid nitrogen injection system was commissioned and set up to perform high-pressure injections into an open vessel. The system is used for quasi-steady flow tests used for the characterisation of the direct injection process for cryogenic engines. An electro-hydraulic valve actuator provides intricate control of the valve lift, with a minimum cycle time of 3âŻms and a frequency of up to 20âŻHz. With additional sub-cooling, liquid phase injections from 14 to 94âŻbar were achieved. Results showed an increase in the injected mass with the increase in pressure, and decrease in temperature. The injected mass was also observed to increases linearly with the valve lift. Better control of the injection process, minimises the number of variables, providing more comparable and repeatable sets of data. Implications of the results on the engine performance were also discussed
Memory CD8 + T cells exhibit tissue imprinting and nonâstable exposureâdependent reactivation characteristics following bloodâstage Plasmodium berghei ANKA infections
From Wiley via Jisc Publications RouterHistory: received 2020-11-02, rev-recd 2021-08-09, accepted 2021-08-13, pub-electronic 2021-08-27Article version: VoRPublication status: PublishedFunder: Medical Research Council; Id: http://dx.doi.org/10.13039/501100000265; Grant(s): G0900487, MR/R010099/1Abstract: Experimental cerebral malaria (ECM) is a severe complication of Plasmodium berghei ANKA (PbA) infection in mice, characterized by CD8+ Tâcell accumulation within the brain. Whilst the dynamics of CD8+ Tâcell activation and migration during extant primary PbA infection have been extensively researched, the fate of the parasiteâspecific CD8+ T cells upon resolution of ECM is not understood. In this study, we show that memory OTâI cells persist systemically within the spleen, lung and brain following recovery from ECM after primary PbAâOVA infection. Whereas memory OTâI cells within the spleen and lung exhibited canonical central memory (Tcm) and effector memory (Tem) phenotypes, respectively, memory OTâI cells within the brain postâPbAâOVA infection displayed an enriched CD69+CD103â profile and expressed low levels of Tâbet. OTâI cells within the brain were excluded from shortâterm intravascular antibody labelling but were targeted effectively by longerâterm systemically administered antibodies. Thus, the memory OTâI cells were extravascular within the brain postâECM but were potentially not resident memory cells. Importantly, whilst memory OTâI cells exhibited strong reactivation during secondary PbAâOVA infection, preventing activation of new primary effector T cells, they had dampened reactivation during a fourth PbAâOVA infection. Overall, our results demonstrate that memory CD8+ T cells are systemically distributed but exhibit a unique phenotype within the brain postâECM, and that their reactivation characteristics are shaped by infection history. Our results raise important questions regarding the role of distinct memory CD8+ Tâcell populations within the brain and other tissues during repeat Plasmodium infections
Chromosomal Instability by Inefficient Mps1 Auto-Activation Due to a Weakened Mitotic Checkpoint and Lagging Chromosomes
BACKGROUND: Chromosomal instability (CIN), a feature widely shared by cells from solid tumors, is caused by occasional chromosome missegregations during cell division. Two of the causes of CIN are weakened mitotic checkpoint signaling and persistent merotelic attachments that result in lagging chromosomes during anaphase. PRINCIPAL FINDINGS: Here we identify an autophosphorylation event on Mps1 that is required to prevent these two causes of CIN. Mps1 is phosphorylated in mitotic cells on at least 7 residues, 4 of which by autophosphorylation. One of these, T676, resides in the activation loop of the kinase domain and a mutant that cannot be phosphorylated on T676 is less active than wild-type Mps1 but is not kinase-dead. Strikingly, cells in which endogenous Mps1 was replaced with this mutant are viable but missegregate chromosomes frequently. Anaphase is initiated in the presence of misaligned and lagging chromosomes, indicative of a weakened checkpoint and persistent merotelic attachments, respectively. CONCLUSIONS/SIGNIFICANCE: We propose that full activity of Mps1 is essential for maintaining chromosomal stability by allowing resolution of merotelic attachments and to ensure that single kinetochores achieve the strength of checkpoint signaling sufficient to prevent premature anaphase onset and chromosomal instability. To our knowledge, phosphorylation of T676 on Mps1 is the first post-translational modification in human cells of which the absence causes checkpoint weakening and CIN without affecting cell viability
Randomised, open-label, phase II study of Gemcitabine with and without IMM-101 for advanced pancreatic cancer
Background:
Immune Modulation and Gemcitabine Evaluation-1, a randomised, open-label, phase II, first-line, proof of concept study (NCT01303172), explored safety and tolerability of IMM-101 (heat-killed Mycobacterium obuense; NCTC 13365) with gemcitabine (GEM) in advanced pancreatic ductal adenocarcinoma.
Methods:
Patients were randomised (2â:â1) to IMM-101 (10âmgâmlâl intradermally)+GEM (1000âmgâmâ2 intravenously; n=75), or GEM alone (n=35). Safety was assessed on frequency and incidence of adverse events (AEs). Overall survival (OS), progression-free survival (PFS) and overall response rate (ORR) were collected.
Results:
IMM-101 was well tolerated with a similar rate of AE and serious adverse event reporting in both groups after allowance for exposure. Median OS in the intent-to-treat population was 6.7 months for IMM-101+GEM v 5.6 months for GEM; while not significant, the hazard ratio (HR) numerically favoured IMM-101+GEM (HR, 0.68 (95% CI, 0.44â1.04, P=0.074). In a pre-defined metastatic subgroup (84%), OS was significantly improved from 4.4 to 7.0 months in favour of IMM-101+GEM (HR, 0.54, 95% CI 0.33â0.87, P=0.01).
Conclusions:
IMM-101 with GEM was as safe and well tolerated as GEM alone, and there was a suggestion of a beneficial effect on survival in patients with metastatic disease. This warrants further evaluation in an adequately powered confirmatory study
Aspects de la génomique des Penicilliums : Assemblage de génome par Peignage Moléculaire, échange génétique dans les aliments et potentiel de production de métabolites secondaires
Penicillium are filamentous fungi belonging to the Ascomycota genus. Penicillium species have been used by Man for centuries in food making processes. More recently they have also been used in the biotechnology industry for the production of compounds of pharmaceutical interest. Some Penicillium species are food spoilage agents, pathogens of plants including fruits. Aspects of their genomics are largely unknown. In this study, we analysed the genomes of two newly sequenced species, Penicillium roqueforti and Penicillium camemberti. Here we report the development of a new methodology for improving and validating genome assembly using an original single DNA molecule technology, Molecular Combing. Using this methodology we were able to produce a high quality genome assembly of Penicillium roqueforti. This work also reports the multiple and recurrent horizontal transfer of a large genomic island of over half a megabase between several Penicillium species. This horizontal transfer indicates a higher frequency of lateral genetic exchange between cheesemaking fungi than previously expected. Finally, we present an early assessment of the genomic potential for secondary metabolite production in these important food associated penicilliums.Les Penicilliums sont des champignons filamenteux appartenant au genre Ascomycota. Ces champignons ont Ă©tĂ© utilisĂ©s par lâhomme pour la production de nourriture depuis des siĂšcles. Plus rĂ©cemment, ils ont aussi Ă©tĂ© utilisĂ©s dans lâindustrie biotechnologique pour la production de composĂ©s chimiques dâintĂ©rĂȘts pharmaceutiques. Certaines espĂšces de Penicillium sont par ailleurs des moisissures contaminants certains aliments, dâautres sont des pathogĂšnes de plantes, y compris de certains fruits. Leur gĂ©nomique est globalement peut connue. Dans cette Ă©tude, nous avons analysĂ© les gĂ©nomes de deux espĂšces nouvellement sĂ©quencĂ©es, Penicillium roqueforti et Penicillium camemberti. Nous reportons ici le dĂ©veloppement dâune nouvelle mĂ©thodologie pour lâamĂ©lioration et la validation dâassemblage de gĂ©nomes en utilisant une technologie permettant lâobservation de molĂ©cules dâADN unique, le Peignage MolĂ©culaire. En utilisant cette mĂ©thode, nous avons amĂ©liorĂ© lâassemblage de Penicillium roqueforti. Ce manuscrit dĂ©crit aussi de multiples occurrences dâun transfert horizontal dâun ilot gĂ©nomique de plus de cinq cent kilobases entre plusieurs Penicillium. Ce cas de transfert horizontal indique une frĂ©quence dâĂ©change latĂ©ral de matĂ©riel gĂ©nĂ©tique plus forte quâattendue. Enfin nous prĂ©sentons un inventaire prĂ©liminaire du potentiel gĂ©nomique pour la production de mĂ©tabolites secondaires dans ces importants Penicillium alimentaires
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