Safflower (Carthamus Tinctorius L.) a Potential Source of Drugs against Cryptococcal Infections,Malaria and Leishmaniasis

In this research we present that Carthamus Tinctorius L. (gen. Asteraceae, otherwise known as Safflower) (Fig. 1) may contain agents active in Cryptococcal infections, malaria and Leishmaniasis, as treatment options are becoming scarce due to drug resistance development. Phytochemistry and pharmacological activities (antimicrobial, antimalarial, antileishmanial) of C. tinctorius L. were analyzed. The composition of volatile oil of safflower dried flowers was analyzed by gas chromatography-mass spectrophotometry with flame ionization detector (GC-FID) and in vitro sensitivity assays were performed to assess biological activity. 8 known and 3 unknown compounds were detected in the extract (Fig. 1). Then the Safflower ointment was manufactured and its acute toxicity study on rats was tested. The volatile oil of C. tinctorius L exhibited activity against Cryptococcus neoformans, Plasmodium falciparum and Leishmania donovani. Safflower volatile oil has anticryptococcal, antimalarial and antileishmanial effects. The prepared ointment had an excellent acute toxicity safety profile.     

The pesticin receptor of Yersinia enterocolitica: a novel virulence factor with dual function

The iron-repressible outer membrane protein FyuA of Yersinia enterocolitica operates as a receptor with dual function: (i) as a receptor for the Y. pestis bacterlocin pesticin, and (ii) as a receptor for yersiniabactin, a siderophore that is produced by mouse-viruient Y. enterocolitica strains of biogroup IB. Cloning of the FyuA-encoding gene was achieved by mobilization of a genomic cosmid library of the pesticin-sensitive and mouse-virulent Y. enterocolitica O:8 strain WA into the pesticin-reslstant WA fyuA mutant and subsequent in vivo selection of transconjugants for the ability to survive and multiply in mice (phenotype mouse viruience). The reisolated transconjugants which survived in mice for 3d harboured a unique cosmid and phenotypicaity were pesticin sensitive. From this cosmid a 2650 bp SalI-PstI fragment conferring pesticin sensitivity was subcioned. Sequencing of this DNA fragment revealed a single open reading frame of 2022 bp, which encodes a deduced polypeptide of 673 amino acids with a predicted molecular mass of 73 677 Da. Cleavage of a putative signal sequence composed of 22 amino acids should lead to a mature protein of 651 amino acids with a molecular mass of 71 368 Da. The open reading frame is preceded by a sequence which shares homoiogy with the postulated consensus Fur iron-repressor protein-binding site. FyuA shows homology to other iron-regulated TonB-dependent outer membrane proteins with receptor functions (e.g. BtuB, CirA, FepA, lutA, FhuA, FoxA, FcuA). On the basis of multiple alignment of amino acid sequences of FyuA and other TonB-dependent receptors, a phylogenetic tree was constructed, demonstrating that FyuA probably belongs to the citrate subfamily or represents a new subfamily of TonB-dependent receptors. Moreover, by complementation of the WA fyuA mutant by the cioned fyuA gene.     

Virulence of Yersinia enterocolitica is closely associated with siderophore production, expression of an iron-repressible outer membrane polypeptide of 65 000 Da and pesticin sensitivity

Iron-repressible outer membrane proteins (Irp) and siderophore production of Yersinia enterocolitica, serotype 08, were subjected to analysis. Here four Irps of apparent molecular weights of 62000, 65000, 74000 and 75000 could be identified which were expressed constitutively by a fur mutant. Production of a novel catechol-containing siderophore (denoted yersiniabactin) was detected by siderophore-indicator agar (chrome azurol S) and feeding experiments. Growth support by yersiniabactin under iron-restricted conditions was TonB- and Irp65-dependent and correlated with pesticin-sensitivity of Yersinia enterocolitica and Escherichia coliø. From these results we conclude that Irp65 of Y. enterocolitica functions as yersiniabactin receptor (FyuA) and as pesticin receptor. By immunoblotting using rabbit antibodies against Irp65 and chrome azurol S-agar, we were able to demonstrate that all tested mouse-lethai Y. enterocoiitica and Yersinia pseudotuberculosis strains of different serotypes express siderophores and Irp65. Moreover, the anti-lrp65 rabbit serum did not cross-react with the known iron-repressible high-molecular-weight proteins (HMWPs). Evidently, the mouse lethality trait in enteropathogenic Yersinia spp. is closely associated with a novel iron-uptake system, comprising the production of a siderophore and a siderophore receptor of apparent molecular mass 65 000 Da.