Cancer cell cytotoxicity was used to guide the isolation of nine new swinholide-related compounds, named samholides A-I (1-9), from an American Samoan marine cyanobacterium cf. Phormidium sp. Their ...structures were determined by extensive analysis of 1D and 2D NMR spectroscopic data. The new compounds share an unusual 20-demethyl 44-membered lactone ring composed of two monomers, and they demonstrate structural diversity arising from geometric isomerization of double bonds, sugar units with unique glyceryl moieties and varied methylation patterns. All of the new samholides were potently active against the H-460 human lung cancer cell line with IC
values ranging from 170 to 910 nM. The isolation of these new swinholide-related compounds from a marine cyanobacterium reinvigorates questions concerning the evolution and biosynthetic origin of these natural products.
The arrangement of the apparatus “DACON” for examining buoyancy driven thermal convection caused by microgravity environment aboard a spacecraft is expounded. Experiments carried out with the sensor ...“DACON” on board the Orbital Station “Mir” during 25th – 28th missions in 1998 – 2000 are presented. The results of measurements of convection and evaluation of low-frequency microacceleration components in different modules and for various regimes of crew and Station activity are reported.
In this study, we have used an approach that allows us to determine in what region of the polypeptide chain of protein it is required to insert a disulphide bond in order to stabilize it. In our ...previous paper Melnik et al., JBSD. 2012 it was proposed that to search for a "weak" site in the protein, it is possible to use programs (for example, PONDR-FIT and IsUnstruct) finding intrinsic disorder protein regions. We suggested that in structured globular proteins, such programs predict not protein regions in the polypeptide chain disordered under native conditions, but "weakened", feebly stabilized ones. Accordingly, an artificial introduction of SS-bridges using mutations in such regions would reliably result in the protein stabilization. We have taken advantage of this approach to stabilize protein Gαo from Drosophila melanogaster. The designed SS-bridge increased by 4 degrees the melting temperature of one domain of protein Gαo.
The method for the detection of 2,4-dinitrophenol (DNP) in solution is proposed. This method employs the sensors based on silicon nanowire field-effect transistors with protective layers of high-k ...dielectrics, whose surface is functionalized with an amino silane. Direct highly sensitive detection of DNP has been demonstrated, and the lowest detectable concentration of DNP was determined to be 10−14 M. Silicon-on-insulator nanowire (SOI-NW) sensors can well be employed for the rapid detection of a wide range of toxic and explosive compounds by selection of sensor surface modification techniques.
The detection of influenza A virions with a nanoribbon detector (NR detector) has been demonstrated. Chips for the detector have been fabricated based on silicon-on-insulator nanoribbon structures ...(SOI nanoribbon chip), using a complementary metal-oxide-semiconductor (CMOS)-compatible technology-by means of gas-phase etching and standard optical photolithography. The surface of the SOI nanoribbon chip contains a matrix of 10 nanoribbon (NR) sensor elements. SOI nanoribbon chips of n-type conductance have been used for this study. For biospecific detection of target particles, antibodies against influenza virus have been covalently immobilized onto NRs. Influenza A virus detection was performed by real-time registration of the source-drain current through the NRs. The detection of the target viral particles was carried out in buffer solutions at the target particles concentration within the range from 10
to 10
viral particles per milliliter (VP/mL). The lowest detectable concentration of the target viral particles was 6 × 10
M (corresponding to 10
VP/mL). The use of solutions containing ~10
to 10
VP/mL resulted in saturation of the sensor surface with the target virions. In the saturation mode, detection was impossible.
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