Anti-Biotin polyclonal antibody [FITC]

This work demonstrates that the biotinylated phenylalanine (biotin-Phe) monomers can be self-assembled into biotin-Phe nanoparticle (biotin-FNP) under mild conditions. The resulting biotin-FNP could be used as the signal enhancer for the assay of caspase-3 activity and evaluation of cell apoptosis. Specifically, the biotinylated Asp-Glu-Val-Asp (DEVD)-containing peptide substrate was immobilized on a gold electrode surface as the specific caspase-3 cleavage site. Through the strong interaction between biotin and the linker of streptavidin (SA), the in situ formation of biotin-FNP networks was initiated on the electrode surface, thus resulting in a significant increase in the electron transfer resistance. However, once the peptide substrate was cleaved by caspase-3, the biotin tag would be detached from the sensor surface, thus hampering the capture of SA and the formation of biotin-FNP networks. The method was successfully utilized to monitor caspase-3 activity in HeLa cells treated by various anticancer reagents. The impedimetric biosensor holds great potential for cell apoptosis evaluation and anticancer drug discovery. Moreover, the signal amplification strategy using the self-assembled biotin-FNP networks can potentially be applied to develop novel affinity biosensors for the detection of proteins, nucleic acids and proteases.

Propagation conditions have been shown to be of considerable importance for the fermentation ability ofSaccharomyces cerevisiae. The limited tolerance of yeast to inhibitors present in lignocellulosic hydrolysates is a major challenge in second-generation bioethanol production. We have investigated the hypothesis that the addition of nutrients during propagation leads to yeast cultures with improved ability to subsequently ferment lignocellulosic materials. This hypothesis was tested with and without short-term adaptation to wheat straw or corn stover hydrolysates during propagation of the yeast. The study was performed using the industrial xylose-fermentingS. cerevisiaestrain CR01. Adding a mixture of pyridoxine, thiamine, and biotin to unadapted propagation cultures improved cell growth and ethanol yields during fermentation in wheat straw hydrolysate from 0.04 g g(-1)to 0.19 g g(-1)and in corn stover hydrolysate from 0.02 g g(-1)to 0.08 g g(-1). The combination of short-term adaptation and supplementation with the vitamin mixture during propagation led to ethanol yields of 0.43 g g(-1)in wheat straw hydrolysate fermentation and 0.41 g g(-1)in corn stover hydrolysate fermentation. These ethanol yields were improved compared to ethanol yields from cultures that were solely short-term adapted (0.37 and 0.33 g g(-1)). Supplementing the propagation medium with nutrients in combination with short-term adaptation was thus demonstrated to be a promising strategy to improve the efficiency of industrial lignocellulosic fermentation.