A series of conformationally flexible furan-derived allocolchicinoids was prepared from commercially available colchicine in good to excellent yields using a three-step reaction sequence. Cytotoxicity studies indicated the potent activity of two compounds against human epithelial and lymphoid cell lines (AsPC-1, HEK293, and Jurkat) as well as against Wnt-1 related murine epithelial cell line W1308. The results of in vitro experiments demonstrated that the major effect of these compounds was the induction of cell cycle arrest in the G2/M phase as a direct consequence of effective tubulin binding. In vivo testing of the most potent furanoallocolchicinoid 10c using C57BL/6 mice inoculated with Wnt-1 tumor cells indicated significant inhibition of the tumor growth.

We report a novel family of natural lipoglycopeptides produced by Streptomyces sp. INA-Ac-5812. Two major components of the mixture, named gausemycins A and B, were isolated, and their structures were elucidated. The compounds are cyclic peptides with a unique peptide core and several remarkable structural features, including unusual positions of D-amino acids, lack of the Ca 2+ -binding Asp-X-Asp-Gly (DXDG) motif, tyrosine glycosylation with arabinose, presence of 2-amino-4-hydroxy-4-phenylbutyric acid (Ahpb) and chlorinated kynurenine (ClKyn), N-acylation of the ornithine side chain. These major components of the peptide antibiotic family have pronounced activity against Grampositive bacteria. The mechanism of action of gausemycins was explored by a number of methods, showing significant differences compared to glycopeptides and related lipopeptides. Gausemycins exhibit only slight Ca 2+ -dependence of antimicrobial activity and induce no pore formation at low concentrations. Moreover, there is no detectable accumulation of cell wall biosynthesis precursors under treatment with gausemycins.

Ubiquitous fungus Aspergillus fumigatus (A. fumigatus) is involved in invasive pulmonary aspergillosis (IPA), a frequent infection in immunocompromized patients. Genetic differences are likely to play a role predisposing to IPA. This study was aimed to compare six genetically different mouse strains in their susceptibility to IPA and to determine possible mechanisms involved in the pathogenesis of this infection. Immunosuppressed BALB/c and C57BL/6 mice infected with A. fumigatus conidia were more resistant to IPA than DBA/1, DBA/2, CBA, and A/Sn strains. Phagocytosis of A. fumigatus conidia by blood polymorphonuclear neutrophils (PMN) or bone marrow derived dendritic cells showed no difference between strains. All IPA susceptible strains demonstrated decreased PMN influx into the lungs during infection compared with resistant strains. Flow cytometry analysis of the composition of lung infiltrating cells showed that IPA susceptible mice had a decreased number of phagocytes before the infection. After infection the numbers of Gr-1(+)CD11b(+) PMN cells in the lungs of immunosuppressed mice increased from 10-20% to 50-60% while the percentage of CD11(+)F4/80(+) resident macrophages was unchanged. Among susceptible strains DBA/2 and A/Sn have a defect in C5 component of complement. Injection of normal serum into complement deficient but not into complement sufficient CBA or DBA/1 mice significantly improved their survival. We showed that complement replacement significantly increased PMN homing to the lungs of complement deficient mice. Thus, defect in complement system can predispose to IPA. Our results demonstrated that early influx of PMN into the lungs of mice is important for the resistance to IPA.

Background Numerous data obtained by different research laboratories indicate that specific IgE production is triggered independently of specific IgG or IgA ones and so it is not linked to fully matured germinal centers formation in the secondary lymphoid organs. The aim of this study was to clarify whether specific IgE production is triggered by low antigen doses administrated in tertiary tissues enriched by lymphoid structures. Methods Ovalbumin (OVA) in different doses (100 ng to 10 μg) was administrated three times a week for 4–5 weeks intraperitoneally (i.p.) or subcutaneously (s.c.) to female BALB/c mice in the wither region which is enriched in fat-associated lymphoid clusters or in the foot pad region not containing them. Results OVA-specific IgE was predominantly induced by low but not high antigen doses and only after immunization into the withers. IgE isotype switching was triggered exclusively in the withers adipose tissue but not in the regional lymph nodes while mature IgE expressing cells were observed both in the withers and lymph nodes. Anti-proliferative genotoxic stress inducing drugs shifted the balance from IgG1 towards IgE production. Conclusions Tertiary lymphoid structures possess unique environment where B-cell antibody isotype switching to IgE predominantly occurs. This phenomenon is partially explained by hampered proliferation of B-cells in these structures.

Chitosan (Chi) is a natural biodegradable cationic polymer with remarkable potency as a vehicle for drug or vaccine delivery. Chi possesses multiple groups, which can be used both for Chi derivatization and for particle formation. The aim of this work was to produce stable nanosized range Chi gels (nanogels, NGs) with different charge and to study the driving forces of complex formation between Chi NGs and proteins or peptides. Positively charged NGs of 150 nm in diameter were prepared from hexanoyl chitosan (HC) by the ionotropic gelation method while negatively charged NGs of 190 nm were obtained from succinoyl Chi (SC) by a Ca 2+ coacervation approach. NGs were loaded with a panel of proteins or peptides with different weights and charges. We show that NGs preferentially formed complexes with oppositely charged molecules, especially peptides, as was demonstrated by gel-electrophoresis, confocal microscopy and HPLC. Complex formation was accompanied by a change in zeta-potential and decrease in size. We concluded that complex formation between Chi NGs and peptide/proteins is mediated mostly by electrostatic interactions.