Capnocytophaga canimorsus : genomic characterization of a specialised host-dependent lifestyle and implications in pathogenesis

Here is presented the complete 2,571,405-bp genome sequence of Capnocytophaga canimorsus strain 5 (Cc5), a strain that was isolated from a fatal septicaemia. Phylogenetic analysis of conserved genes supports the inclusion of C. canimorsus into the Cytophaga-Flavobacteria-Bacteroides (CFB) phylum and indicates close relationships with environmental flavobacteria as Flavobacterium johnsoniae and Gramella forsetii. In addition, relative phylogenetic topology of Capnocytophaga species shows that C. canimorsus share more sequence similarities with human host associated Capnocytophaga species than species from the latter group among themselves (e.g. C. gingivalis and C. ochracea). As compared to other Capnocytophaga, C.canimorsus seems to have differentiated by large-scale horizontal gene transfer compensated by gene losses. Consistently with a relatively reduced genome size, genome scale metabolic modelling suggested a reduced global pleiotropy as it is illustrated by the presence of a split TCA cycle or by the metabolic uncoupling of the hexoses and N-acetylhexosamines pathways. In addition and in agreement with the high content in HCO3- and Na+ ions in saliva, we predicted a CO2-dependent fumarate respiration coupled to a Na+ ions gradient based respiratory chain in Cc5. All together these observations draw the picture of an organism with a high degree of specialization to a relatively homeostatic host environment. Unexpectedly, the genome of Cc5 did not encode classical complex virulence functions as T3SSs or T4SSs. However it exhibits a very high relative number of predicted surface-exposed lipoproteins. Many of them are encoded within 13 different putative polysaccharide utilization loci (PULs), a hallmark of the CFB group, discovered in the gut commensal Bacteroides thetaiotaomicron. When Cc5 bacteria were grown on Hek293 cells, at least 12 PULs were expressed and detected by mass spectrometry. Semi-quantitative analysis of the Cc5 surfome identified 73 surface exposed proteins among which 40 were lipoproteins and accounted for 76% of the total quantification. Interestingly, 28 proteins (38%) were encoded by 9 different PULs and corresponded to more than 54% of total MS-flying peptides detected. A systematic knockout analysis of the 13 PULs revealed that 6 PULs are involved in growth during cell culture infections with most dramatic effect observed for ΔPUL5. Proteins encoded by PUL5, one of the most abundant PULs (12%), turned out to be devoted to foraging glycans from N-linked glycoproteins as fetuin but also IgG. It was not only essential for growth on cells but also for survival in mice and in fresh human serum therefore representing a new type of virulence factor. Further characterization of the PUL5 deglycosylation mechanism revealed that deglycosylation is achieved by a large surface complex spanning the outer membrane and consisting of five PUL5 encoded Gpd proteins and the Siac sialidase. GpdCDEF contribute to the binding of glycoproteins at the bacterial surface while GpdG is a β-endo-glycosidase cleaving the N-linked oligosaccharide after the first N-linked GlcNAc residue. We demonstrate that GpdD, -G, -E and -F are surface-exposed outer membrane lipoproteins while GpdC resembles a TonB-dependent OM transporter and presumably imports oligosaccharides into the periplasm after cleavage from glycoproteins. Terminal sialic acid residues of the oligosaccharide are then removed by SiaC in the periplasm. Finally, degradation of the oligosaccharide proceeds sequentially from the desialylated non reducing end by the action of periplasmic exoglycosidases, including β-galactosidases, β-N-Acetylhexosaminidases and α-mannosidases. Genome sequencing of additional C. canimorsus strains have been performed with the only use of second generation sequencing methods (Solexa and 454). Two assembling approaches were developed in order to enhance assembly capacities of pre-existing tools. Draft assemblies of the three pathogenic human blood isolates C. canimorsus 2 (three contigs), C. canimorsus 11 (152 contigs) and C. canimorsus 12 (63 contigs) are presented here. Comparative genomics including genomes of four available human hosted Capnocytophaga species stressed C. canimorsus exclusively conserved features as an oxidative respiratory chain and an oxidative stress resistance or the presence of a Cc5 specific PULs content. Therefore we propose these features as potential factors involved in the pathogenesis of C. canimorsus

Generative AI and the future for China’s diplomacy

This paper explores the challenges of Generative AI technologies to China’s diplomatic engagement worldwide. First, it examines the discourse in China about the development of ChatGPT, by focusing on the treatment of the technology and the possible risks and opportunities regarding international affairs. Second, the article highlights four challenges: (1) the securitization of AI, where import/export controls, data access, and semiconductors open a new field of research; (2) the (techno-) socialism with Chinese characteristics and the response to the arrival of cutting-edge technologies from U.S. capital and their impact on the development of a local model; (3) the soft censorship: the development of a technology that responds in the "correct" way (i.e., in line with the ruling ideology) by discriminating the suitability of sources/data deemed correct and appropriate for the public sphere; (4) the impact on public diplomacy, as AI projects an aura of innovation and technological reputation. In summary, this paper contributes to the theoretical debate on the challenges posed by Generative IA technologies in the context of China’s diplomatic practices

The Use of Experimental Evolution to Study the Response of Pseudomonas aeruginosa to Single or Double Antibiotic Treatment

The widespread use of antibiotics promotes the evolution and dissemination of drug resistance and tolerance. Both mechanisms promote survival during antibiotic exposure and their role and development can be studied in vitro with different assays to document the gradual adaptation through the selective enrichment of resistant or tolerant mutant variants. Here, we describe the use of experimental evolution in combination with time-resolved genome analysis as a powerful tool to study the interaction of antibiotic tolerance and resistance in the human pathogen Pseudomonas aeruginosa . This method guides the identification of components involved in alleviating antibiotic stress and helps to unravel specific molecular pathways leading to drug tolerance or resistance. We discuss the influence of single or double drug treatment regimens and environmental aspects on the evolution of antibiotic resilience mechanisms

Mises y el consumo de cerveza campesina.

In this text I will analyze how, in the texts of Mises -central author in the strategy and deployment of neoliberalism- a problem related to subjectivity and like is highlighted.In opposition to an interpretation of man who, as homo economicus, mechanically orients his actions in order to obtain profits. The aforementioned author recognizes the existence of infinity of reasons why man chooses to act, beyond what can provide him with an immediate economic benefit. In this sense, subjective meanings, likes, emotions and feelings become objects to be incorporated into the neoliberal government strategy.En este trabajo analizaré de qué modo, en los textos de Mises -autor central en la estrategia y el despliegue del neoliberalismo- se pone de relieve una problemática relacionada con la subjetividad y el gusto. En oposición a una interpretación del hombre que, en tanto homo economicus, orienta mecánicamente sus acciones con el fin de obtener ganancias. El citado autor reconoce la existencia de una infinidad de motivos por los cuales el hombre elige actuar, más allá de aquello que pueda brindarle un beneficio económico inmediato. En este sentido, las significaciones subjetivas, los gustos, las emociones y los sentimientos se constituyen en objetos a ser incorporados dentro de la estrategia de gobierno neoliberal

Asymptotic Mean-Value Formulas for Solutions of General Second-Order Elliptic Equations

We obtain asymptotic mean-value formulas for solutions of second-order elliptic equations. Our approach is very flexible and allows us to consider several families of operators obtained as an infimum, a supremum, or a combination of both infimum and supremum, of linear operators. The families of equations that we consider include well-known operators such as Pucci, Issacs, and k-Hessian operators

Draft Genome Sequences of Three Capnocytophaga canimorsus Strains Isolated from Septic Patients

Capnocytophaga canimorsus is a bacterium from the normal oral flora of dogs and cats that causes rare generalized infections in humans. In an attempt to determine whether infections could be caused by a subset of strains and to identify pathogenicity factors, we sequenced the genomes of three strains isolated from human infections

Draft Genome Sequences of Three Capnocytophaga cynodegmi Strains Isolated from the Oral Cavity of Healthy Dogs

Here, we present the draft genome sequences of three strains of Capnocytophaga cynodegmi. In contrast to the very close relationship among them, C. cynodegmi and Capnocytophaga canimorsus differ dramatically in terms of virulence in humans. Comparative genomics provided some understanding on how Capnocytophaga species may switch from being dog commensals to human pathogens

Draft Genome Sequences of Three Capnocytophaga canimorsus Strains Isolated from Healthy Canine Oral Cavities

Here, we present the draft genome sequences of three strains of Capnocytophaga canimorsus, each isolated from a different dog's mouth. Genome analysis provided evidence that these organisms may belong to a different nonpathogenic subtype of C. canimorsus