Search results for "Host"

Clinical significance of Pneumocystis jirovecii DNA detection by real-time PCR in hematological patient respiratory specimens

2020

Evolutionary history conditions the timing of transmission in vesicular stomatitis virus.

2001

It has been postulated that early transmitted viruses would evolve to be more virulent than late transmitted ones. The reason for this prediction is that early transmission selects for rapid viral replication and, consequently, rapid host death, whereas late transmission would select for slow-replicating viruses that permit longer survival to the host. To test this prediction, experimental lineages of vesicular stomatitis virus (VSV) had been adapted to three different transmission dynamics during more than 100 generations. Transmission dynamic differed in the stage of infection at which transmission took place: early, intermediate or late. Regardless the timing of transmission imposed duri…

Cooperation and conflict in host manipulation: interactions among macro-parasites and micro-organisms.

2014

10 pages; International audience; Several parasite species are known to manipulate the phenotype of their hosts in ways that enhance their own transmission. Co-occurrence of manipulative parasites, belonging to the same species or to more than one species, in a single host has been regularly observed. Little is known, however, on interactions between co-occurring manipulative parasites with same or different transmission routes. Several models addressing this problem have provided predictions on how cooperation and conflict between parasites could emerge from multiple infections. Here, we review the empirical evidence in favor of the existence of synergistic or antagonistic interactions bet…

Honey Bee Suppresses the Parasitic Mite Vitellogenin by Antimicrobial Peptide

2020

AbstractThe negative effects of honey bee parasitic mites and deformed wing virus (DWV) on honey bee and colony health have been well characterized. However, the relationship between DWV and mites, particularly viral replication inside the mites, remains unclear. Furthermore, the physiological outcomes of honey bee immune responses stimulated by DWV and the mite to the host (honey bee) and perhaps the pathogen/parasite (DWV/mite) are not yet understood. To answer these questions, we studied the tripartite interactions between the honey bee,Tropilaelaps mercedesae, and DWV as the model.T. mercedesaefunctioned as a vector for DWV without supporting active viral replication. Thus, DWV negligib…

Early Development of the Gut Microbiota and Immune Health

2014

In recent years, the increase in human microbiome research brought about by the rapidly evolving “omic” technologies has established that the balance among the microbial groups present in the human gut, and their multipronged interactions with the host, are crucial for health. On the other hand, epidemiological and experimental support has also grown for the ‘early programming hypothesis’, according to which factors that act in utero and early in life program the risks for adverse health outcomes later on. The microbiota of the gut develops during infancy, in close interaction with immune development, and with extensive variability across individuals. It follows that the specific process of…

TLR2: for or against Candida albicans?

2005

In a recent issue of Trends in Microbiology, Netea and coworkers presented their opinion that toll-like receptors (TLRs) are involved in escape from the defense mechanisms of the host [1]. In their article, the authors clearly identified three major TLR-mediated escape mechanisms that are used by microbial pathogens, such as Yersinia, Mycobacterium and Candida. Here, we wish to comment on the roll of TLR2 in Candida albicans infections. Netea's interesting hypothesis, that TLR2 expression might confer to mice an increased susceptibility to C.

Biocontrol of the Major Plant Pathogen Ralstonia solanacearum in Irrigation Water and Host Plants by Novel Waterborne Lytic Bacteriophages

2019

Three new lytic bacteriophages were found to effectively control the pathogen Ralstonia solanacearum, a quarantine bacterium in many countries, and causative agent of bacterial wilt, one of the most important vascular plant diseases. Bacterial wilt management has been carried out with fluctuating effects, suggesting the need to find alternative treatments. In this work, three lytic phages were isolated from environmental water from geographically distant regions in Spain. They proved to specifically infect a collection of R. solanacearum strains, and some of the closely related pathogenic species Ralstonia pseudosolanacearum, without affecting non-target environmental bacteria, and were abl…

Study of the cwaRS-ldcA Operon Coding a Two-Component System and a Putative L,D-Carboxypeptidase in Lactobacillus paracasei

2020

International audience; The cell surface is the primary recognition site between the bacterium and the host. An operon of three genes, LSEI_0219 (cwaR), LSEI_0220 (cwaS), and LSEI_0221 (ldcA), has been previously identified as required for the establishment of Lactobacillus paracasei in the gut. The genes cwaR and cwaS encode a predicted two-component system (TCS) and ldcA a predicted D-alanyl-D-alanine carboxypeptidase which is a peptidoglycan (PG) biosynthesis enzyme. We explored the functionality and the physiological role of these three genes, particularly their impact on the bacterial cell wall architecture and on the bacterial adaptation to environmental perturbations in the gut. The …

Lymnaea cousinni (Gastropoda: Lymnaeidae) as transmitter of fascioliasis

2007

Dear Editor,In the article entitled “First report of Lymnaea cou-sini Jousseaume, 1887 naturally infected with Fasciolahepatica (Linnaeus, 1758) (Trematoda: Digenea) inMachachi, Ecuador” recently published by AngelVillavicencio A and Mauricio Carvalho de Vasconcellosin Memorias do Instituto Oswaldo Cruz (vol. 100, is-sue 7, pages 735-737, November 2005), it is stated thattheir finding in Ecuador represents the first report ofspecimens of this lymnaeid species naturally infectedby the liver fluke. However, it is well known from longago that this species acts as intermediate host of fascio-liasis in Andean countries. In the first half of the lastcentury, Brumpt et al. (1939-1940) already demo…

The Effect of the Environmental Temperature on the Adaptation to Host in the Zoonotic Pathogen Vibrio vulnificus

2020

Vibrio vulnificus is a zoonotic pathogen that lives in temperate, tropical and subtropical aquatic ecosystems whose geographical distribution is expanding due to global warming. The species is genetically variable and only the strains that belong to the zoonotic clonal-complex can cause vibriosis in both humans and fish (being its main host the eel). Interestingly, the severity of the vibriosis in the eel and the human depends largely on the water temperature (highly virulent at 28°C, avirulent at 20°C or below) and on the iron content in the blood, respectively. The objective of this work was to unravel the role of temperature in the adaptation to the host through a transcriptomic and phen…