Silanol: a bifunctional group for peptide synthesis and late-stage functionalization.

Chemical modification of a specific amino acid residue on peptides represents an efficient strategy to improve their pharmacokinetics and facilitates the potential to achieve post-synthetic diversification of peptides. Herein, we reported the first Pd-catalyzed late-stage ortho-olefination of Tyr residues on peptides with high chemo- and site-selectivity, by employing the easily attached and removable silanol as a bifunctional protecting group and directing group. Up to hexapeptides with variation on amino acid sequences or locations of the Tyr residue and different olefins were compatible with this protocol, which enriched the chemical toolbox for late-stage modification via C(sp2)-H functionalization. Furthermore, the orthogonal protection strategies of Tyr were also developed and could be applied to SPPS.

[Effect of cardiopulmonary bypass on the expression of survivin in neutrophils].

OBJECTIVE: To investigate the effects of cardiopulmonary bypass on neutrophils apoptosis and the expression of survivin. METHODS: Ten patients who scheduled for cardiac surgery under cardiopulmonary bypass were recruited as study group and 10 healthy volunteers as control. Blood samples were obtained before operation, at the end of surgery, and at 24 hours postoperatively. Neutrophils were isolated by density gradient centrifugation and its apoptosis were evaluated by fluorescent microscope and flow cytometry. The expression of survivin protein was examined by Western blotting analysis. Expression level of survivin mRNA was detected by RT-PCR. RESULTS: The apoptotic rate of neutrophils decreased significantly at the end of surgery (P < 0.01), and was still lower at 24 hours postoperatively than before operation (P < 0.05). The expression ratios of survivin protein and mRNA were increased at the end of surgery (P < 0.01), and decreased gently at 24 hours postoperatively but was still higher than before operation (P < 0.05). CONCLUSION: Cardiopulmonary bypass could inhibit neutrophils apoptosis and increase the expression of survivin. The decrease of neutrophils apoptosis was correlated with high expression of survivin.

[Foraging intensity of ants in Solenopsis invicta Buren (Hymenoptera: Formiciddae) invaded and un-invaded habitats].

By the methods of bait (honey, peanut oil, sausage, and mealworm larvae) trap, this paper studied the searching time, recruitment time, and recruitment number of ants in 3 typical habitats invaded and un-invaded by red imported fire ant (Solenopsis invicta) in South China, and analyzed the effects of S. invicta invasion on the foraging intensity of native ants. In S. invicta invaded lawn, the searching time of ants for mealworm larvae and peanut oil was significantly shorter, compared with that in S. invicta un-invaded area. Less difference was observed in the searching time for the 4 baits between S. invicta invaded and un-invaded wasteland, but the recruitment time for peanut oil was significantly longer in invaded than in un-invaded area. The searching time and recruitment time of the ants for the 4 baits had less difference between the invaded and un-invaded litchi orchard. 30 min after setting bait traps, the recruitment number of S. invicta workers on peanut oil, mealworm larvae, and sausage in invaded lawn, and on peanut oil in invaded wasteland was larger than that of native ants, but no significant difference was found in the recruitment number of S. invicta workers and native ants on the baits in invaded litchi orchard.