The Cryptosporidium parvum Kinome

<p>Abstract</p> <p>Background</p> <p>Hundreds of millions of people are infected with cryptosporidiosis annually, with immunocompromised individuals suffering debilitating symptoms and children in socioeconomically challenged regions at risk of repeated infections. There is currently no effective drug available. In order to facilitate the pursuit of anti-cryptosporidiosis targets and compounds, our study spans the classification of the <it>Cryptosporidium parvum </it>kinome and the structural and biochemical characterization of representatives from the CDPK family and a MAP kinase.</p> <p>Results</p> <p>The <it>C</it>. <it>parvum </it>kinome comprises over 70 members, some of which may be promising drug targets. These <it>C. parvum </it>protein kinases include members in the AGC, Atypical, CaMK, CK1, CMGC, and TKL groups; however, almost 35% could only be classified as OPK (other protein kinases). In addition, about 25% of the kinases identified did not have any known orthologues outside of <it>Cryptosporidium spp</it>. Comparison of specific kinases with their <it>Plasmodium falciparum </it>and <it>Toxoplasma gondii </it>orthologues revealed some distinct characteristics within the <it>C. parvum </it>kinome, including potential targets and opportunities for drug design. Structural and biochemical analysis of 4 representatives of the CaMK group and a MAP kinase confirms features that may be exploited in inhibitor design. Indeed, screening <it>Cp</it>CDPK1 against a library of kinase inhibitors yielded a set of the pyrazolopyrimidine derivatives (PP1-derivatives) with IC₅₀values of < 10 nM. The binding of a PP1-derivative is further described by an inhibitor-bound crystal structure of <it>Cp</it>CDPK1. In addition, structural analysis of <it>Cp</it>CDPK4 identified an unprecedented Zn-finger within the CDPK kinase domain that may have implications for its regulation.</p> <p>Conclusions</p> <p>Identification and comparison of the <it>C. parvum </it>protein kinases against other parasitic kinases shows how orthologue- and family-based research can be used to facilitate characterization of promising drug targets and the search for new drugs.</p

Effect of growth temperature on the fatty acid composition of a blue-green alga

The fatty acid composition of the blue-green alga, Anacystis nidulans, was investigated by gas-liquid chromatography at four different growth temperatures with illumination, aeration, cell density, medium composition, and growth rate kept constant. At all temperatures palmitic acid and a hexadecenoic acid presumed to be palmitoleic totaled approximately 90% of the fatty acids present but the ratio of the hexedecenoic to palmitic decreased as the temperature was raised. An octadecenoic and tetradecenoic (probably oleic and myristoleic, respectively) were also present and traces of a heptadecenoic acid and of others were detected. At 26[deg], 32[deg], and 35[deg], the ratio of total unsaturated to saturated acids remained approximately 1[middle dot]0 although the qualitative composition changed, but at 41[deg] the saturated acids predominated, the ratio being 0[middle dot]7. In contrast to other algae and higher plants, polyunsaturated acids were absent in Anacystis which in this way resembles the photosynthetic bacteria.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32105/1/0000155.pd