13 research outputs found
Association between Plasma Antibody Response and Protection in Rainbow Trout Oncorhynchus mykiss Immersion Vaccinated against Yersinia ruckeri
A key hallmark of the vertebrate adaptive immune system is the generation of antigen-specific antibodies from B cells. Fish are the most primitive gnathostomes (jawed vertebrates) possessing an adaptive immune system. Vaccination of rainbow trout against enteric redmouth disease (ERM) by immersion in Yersinia ruckeri bacterin confers a high degree of protection to the fish. The immune mechanisms responsible for protection may comprise both cellular and humoral elements but the role of specific immunoglobulins in this system has been questioned and not previously described. The present study demonstrates significant increase in plasma antibody titers following immersion vaccination and significantly reduced mortality during Y. ruckeri challenge
Phage therapy as an approach to prevent Vibrio anguillarum infections in fish larvae production
Fish larvae in aquaculture have high mortality rates due to pathogenic bacteria, especially the Vibrio species, and ineffective prophylactic strategies. Vaccination is not feasible in larvae and antibiotics have reduced efficacy against multidrug resistant bacteria. A novel approach to controlling Vibrio infections in aquaculture is needed. The potential of phage therapy to combat vibriosis in fish larvae production has not yet been examined. We describe the isolation and characterization of two bacteriophages capable of infecting pathogenic Vibrio and their application to prevent bacterial infection in fish larvae. Two groups of zebrafish larvae were infected with V. anguillarum (âŒ106 CFU mL-1) and one was later treated with a phage lysate (âŒ108 PFU mL-1). A third group was only added with phages. A fourth group received neither bacteria nor phages (fish control). Larvae mortality, after 72 h, in the infected and treated group was similar to normal levels and significantly lower than that of the infected but not treated group, indicating that phage treatment was effective. Thus, directly supplying phages to the culture water could be an effective and inexpensive approach toward reducing the negative impact of vibriosis in larviculture
A history of British seismology
The work of John Milne, the centenary of whose death is marked in 2013, has had a large impact in the development in global seismology. On his return from Japan to England in 1895, he established for the first time a global earthquake recording network, centred on his observatory at Shide, Isle of Wight. His composite bulletins, the âShide Circularsâ developed, in the twentieth century, into the world earthquake bulletins of the International Seismological Summary and eventually the International Seismological Centre, which continues to publish the definitive earthquake parameters of world earthquakes on a monthly basis. In fact, seismology has a long tradition in Britain, stretching back to early investigations by members of the Royal Society after 1660. Investigations in Scotland in the early 1840s led to a number of firsts, including the first network of instruments, the first seismic bulletin, and indeed, the first use of the word âseismometerâ, from which words like âseismologyâ are a back-formation. This paper will present a chronological survey of the development of seismology in the British Isles, from the first written observations of local earthquakes in the seventh century, and the first theoretical writing on earthquakes in the twelfth century, up to the monitoring of earthquakes in Britain in the present day
Diversity and Geographical Distribution of <em>Flavobacterium psychrophilum</em> Isolates and Their Phages: Patterns of Susceptibility to Phage Infection and Phage Host Range
ArtĂculo de publicaciĂłn ISIFlavobacterium psychrophilum is an important fish
pathogen worldwide that causes cold water disease (CWD) or
rainbow trout fry syndrome (RTFS). Phage therapy has been
suggested as an alternative method for the control of this
pathogen in aquaculture. However, effective use of bacteriophages
in disease control requires detailed knowledge about the
diversity and dynamics of host susceptibility to phage infection.
For this reason, we examined the genetic diversity of 49
F. psychrophilum strains isolated in three different areas
(Chile, Denmark, and USA) through direct genome restriction
enzyme analysis (DGREA) and their susceptibility to 33 bacteriophages
isolated in Chile and Denmark, thus covering large
geographical (>12,000 km) and temporal (>60 years) scales of
isolation. An additional 40 phage-resistant isolates obtained
from culture experiments after exposure to specific phageswere
examined for changes in phage susceptibility against the 33
phages. The F. psychrophilum and phage populations isolated
from Chile and Denmark clustered into geographically distinct
groups with respect to DGREA profile and host range,
respectively. However, cross infection between Chilean phage
isolates and Danish host isolates and vice versa was observed.
Development of resistance to certain bacteriophages led to
susceptibility to other phages suggesting that âenhanced infectionâ
is potentially an important cost of resistance in
F. psychrophilum, possibly contributing to the observed coexistence
of phage-sensitive F. psychrophilum strains and lytic
phages across local and global scales. Overall, our results
showed that despite the identification of local communities of
phages and hosts, some key properties determining phage
infection patterns seem to be globally distributed.This work was partially supported by Grant
INNOVA 07CN13PPT-09 of CORFO-Chile, by a grant from The Danish
Council for Independent Research (FNU-09-072829) and The Danish
Directorate for Food, Fisheries and Agri Business (ProAqua, project # 09-
072829) to MMand by the EU-IRSES-funded project AQUAPHAGE to
MM and RE