SwePub
Sök i LIBRIS databas

  Utökad sökning

id:"swepub:oai:DiVA.org:uu-2770"
 

Sökning: id:"swepub:oai:DiVA.org:uu-2770" > Parasite on Crayfish :

Parasite on Crayfish : Characterisation of Their Pathogenesis, Host Interactions and Diversity

Bangyeekhun, Eakaphun, 1973- (författare)
Uppsala universitet,Jämförande fysiologi
Tunlid, Anders, Professor (opponent)
Department of Microbial Ecology, Lund
 (creator_code:org_t)
ISBN 9155453767
Uppsala : Acta Universitatis Upsaliensis, 2002
Engelska 46 s.
Serie: Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, 1104-232X ; 737
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)
Abstract Ämnesord
Stäng  
  • The crayfish plague refractory crayfish, Pacifastacus leniusculus, which can harbour the fungal parasite within melanotic sheath, are found to constitutively express the gene encoding for prophenoloxidase (proPO) after mimicking parasite attack. In contrast, the susceptible crayfish, Astacus astacus, responds to the parasite by increased levels of proPO transcript, particularly in the semigranular haemocytes. The upregulation of proPO could confer a temporary resistance towards the fungal infection, suggesting that additional factors are involved in maintaining the balance between host and parasite. The resistant crayfish may have adapted to the parasite by increasing the transcript level of immune genes. The parasite can be considered as a symbiont since it does not harm the host rather than it activates the immune gene and possibly preventing other pathogens to become established.Two serine proteinase genes encoding a subtilisin-like (AaSP1) and a trypsin (AaSP2) enzyme were isolated from the crayfish plague fungus, Aphanomyces astaci. These proteinases are prepropeptides and generate mature proteins of 39 kDa and 29 kDa, respectively. Characterisation of AaSP1 suggests that the enzyme may be involved in intracellular control mechanisms rather than playing a role in pathogenesis. The AaSP2 transcript was not controlled by catabolic repression, but was induced by crayfish plasma, implying a role in pathogenesis toward the crayfish host. Physiology and genetics of five Aphanomyces strains, which were isolated from moribund crayfish, were characterised with regard to their pathogen diversity. These strains are not virulent against crayfish. Some physiological properties of these strains differed from A. astaci, such as growth rate, germination and production of chitinase. Genetic analysis clearly indicated that they are not related to A. astaci and their name are proposed to be Aphanomyces repetans.The crayfish P. leniusculus was found to be susceptible to white spot syndrome virus infection. The virus has a significant effect to the population of crayfish haemocyte. The number and proportion of granular cell from virus-infected crayfish were higher than in controls, indicating granular cells are more resistant to and may interact by some means with the virus.Two morphotypes of the crayfish parasite Psorospermium haeckeli obtained from different crayfish hosts of different geographical origin were analysed for ribosomal ITS DNA in order to compare their genetic diversity. The sequence difference between them was found largely in ITS 1 and ITS 2 regions, which was variable in length and showed 66% and 58% sequence similarity. Thus, different morphotypes of P. haeckeli are genetically diverse.

Ämnesord

NATURVETENSKAP  -- Biologi -- Zoologi (hsv//swe)
NATURAL SCIENCES  -- Biological Sciences -- Zoology (hsv//eng)

Nyckelord

Zoophysiology
Crayfish
Parasite
Oomycete
Prophenoloxidase
Peroxinectin
Aphanomyces astaci
Psorospermium haecheli
White spot syndrome virus
Zoofysiologi
Animal physiology
Zoofysiologi
biologisk beroendeforskning
Biological Research on Drug Dependence

Publikations- och innehållstyp

vet (ämneskategori)
dok (ämneskategori)

Hitta via bibliotek

Till lärosätets databas

Hitta mer i SwePub

Av författaren/redakt...
Bangyeekhun, Eak ...
Tunlid, Anders, ...
Om ämnet
NATURVETENSKAP
NATURVETENSKAP
och Biologi
och Zoologi
Delar i serien
Comprehensive Su ...
Av lärosätet
Uppsala universitet

Sök utanför SwePub

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy