Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    A malaria scavenger receptor-like protein essential for parasite development (2002)
    Oxford, UK : Blackwell Science Ltd
    Molecular microbiology 45 (2002), S. 0 
    Details
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Malaria parasites suffer severe losses in the mosquito as they cross the midgut, haemolymph and salivary gland tissues, in part caused by immune responses of the insect. The parasite compensates for these losses by multiplying during the oocyst stage to form the infectious sporozoites. Upon human infection, malaria parasites are again attenuated by sustained immune attack. Here, we report a single copy gene that is highly conserved amongst Plasmodium species that encodes a secreted protein named PxSR. The predicted protein is composed of a unique combination of metazoan protein domains that have been previously associated with immune recognition/activation and lipid/protein adhesion interactions at the cell surface, namely: (i) scavenger receptor cysteine rich (SRCR); (ii) pentraxin (PTX); (iii) polycystine-1, lipoxygenase, alpha toxin (LH2/PLAT); (iv) Limulus clotting factor C, Coch-5b2 and Lgl1 (LCCL). In our assessment the PxSR molecule is completely novel in biology and is only found in Apicomplexa parasites. We show that PxSR is expressed in sporozoites of both human and rodent malaria species. Disruption of the PbSR gene in the rodent malaria parasite P. berghei results in parasites that form normal numbers of oocysts, but fail to produce any sporozoites. We suggest that, in addition to a role in sporogonic development, PxSR may have a multiplicity of functions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2958.2002.03118.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Reconstructing the Diversification of α-Esterases: Comparing the Gene Clusters of Drosophila buzzatii and D. melanogaster (2000)
    Springer
    Journal of molecular evolution 51 (2000), S. 149-160 
    Details
    ISSN: 1432-1432
    Keywords: Key words:Drosophila— Gene duplications — Carboxyl/cholinesterases — Phylogeny — Tertiary structure — Evolutionary rates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. A cluster composed of 10 active α-esterase genes and a pseudogene is distributed over 60 kb in the Drosophila melanogaster genome. This paper describes the corresponding cluster in Drosophila buzzatii, whose lineage diverged from that of D. melanogaster when the subgenera Drosophila and Sophophora diverged about 50 Mya. With three exceptions we find that the composition of the cluster is conserved in the two lineages. The location of αE1 in D. melanogaster differs from that of its nearest relative in D. buzzatii, and αE4 has duplicated independently in the two lineages. The nature of these differences indicates that a mechanism exists whereby copies of genes can be placed in opposite orientation and nonadjacent positions within a gene cluster, although this does not seem to be a feature of earlier events in the cluster's evolution. The rates of amino acid change are not significantly different between orthologs, but the rates differ sevenfold among paralogs, indicating that very different selective forces are acting on the genes of the cluster. Mapping of sequence differences onto a model of the tertiary structure of the enzymes indicates that motifs contributing to substrate binding and catalysis have changed radically in the αE4s and suggest that this subgroup of α-esterases may be evolving into a substantially different functional niche.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002390010075
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Biochemistry of Esterases Associated with Organophosphate Resistance in Lucilia cuprina with Comparisons to Putative Orthologues in Other Diptera (1997)
    Springer
    Biochemical genetics 35 (1997), S. 17-40 
    Details
    ISSN: 1573-4927
    Keywords: organophosphorus insecticide resistance ; esterase ; Lucilia cuprina ; Musca domestica
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Esterase activities associated with organophosphate insecticide resistance in the Australian sheep blowfly, Lucilia cuprina, are compared with similar activities in other Diptera. The enzymes making the major contribution to methyl butyrate hydrolysis (“ali-esterase”) in L. cuprina, M. domestica, and D. melanogaster comigrate during electrophoresis. The enzymes in L. cuprina and D. melanogaster correspond to the naphthyl acetate hydrolyzing E3 and EST23 isozymes of those species. These and previously published data suggest that the ali-esterases of all three species are orthologous. Strains of L. cuprina fall into four groups on the basis of quantitative determinations of their ali-estesterase, OP hydrolase, and malathion carboxylesterase activities and these groups correspond to their status with respect to two types of OP resistance. Strains susceptible to OPs have high ali-esterase, low OP hydrolase, and intermediate MCE activities; those resistant to malathion but not diazinon have low ali-esterase, intermediate OP hydrolase, and high MCE activities; those resistant to diazinon but not malathion have low ali-esterase, high OP hydrolase, and low MCE activities; those resistant to both OPs have low ali-esterase, high OP hydrolase, and high MCE activities. The correlated changes among the three biochemical and two resistance phenotypes suggest that they are all properties of one gene/enzyme system; three major allelic variants of that system explain OP susceptibility and the two types of OP resistance. Models are proposed to explain the joint contribution of OP hydrolase and MCE activities to malathion resistance and the invariant association of low ali-esterase and elevated OP hydrolase activities in either type of resistance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022256412623
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...