ABSTRACT
The first total synthesis of MA026 and the identification of its candidate target protein for anti-hepatitis C virus activity are presented. MA026, a novel lipocyclodepsipeptide isolated from the fermentation broth of Pseudomonas sp. RtIB026, consists of a cyclodepsipeptide, a chain peptide, and an N-terminal (R)-3-hydroxydecanoic acid. The first subunit, side chain 2, was prepared by coupling fatty acid moiety 4 with tripeptide 5. The key macrocyclization of the decadepsipeptide at L-Leu(10)-D-Gln(11) provided the second subunit, cyclodepsipeptide 3. Late-stage condensation of the two key subunits and final deprotection afforded MA026. This convergent, flexible, solution-phase synthesis will be invaluable in generating MA026 derivatives for future structure-activity relationship studies. An infectious hepatitis C virus (HCV) cell culture assay revealed that MA026 suppresses HCV infection into host hepatocytes by inhibiting the entry process in a dose-dependent manner. Phage display screening followed by surface plasmon resonance (SPR) binding analyses identified claudin-1, an HCV entry receptor, as a candidate target protein of MA026.
Subject(s)
Antiviral Agents/chemical synthesis , Antiviral Agents/pharmacology , Depsipeptides/chemical synthesis , Depsipeptides/pharmacology , Hepacivirus/drug effects , FermentationABSTRACT
In the ultrasonic atomization of metal nitrate solutions, the molar ratio of metal ions is changed between solution and mist. Small molar metal ions tend to be transferred to mist by ultrasonic wave acceleration, while large molar ions tend to remain in solution. As a result, metal ions can be separated by ultrasonic atomization. We show experimental data and propose a conceptual mechanism for the ultrasonic separation of metal ions.
Subject(s)
Chemistry, Physical/instrumentation , Chemistry, Physical/methods , Ions/isolation & purification , Metals/isolation & purification , Nitrates/chemistry , Ultrasonics , Bismuth/chemistry , Ethanol/chemistry , Ethanol/isolation & purification , Iron/chemistry , Lead/chemistry , Models, Chemical , Potassium/chemistry , Yttrium/chemistryABSTRACT
Redshift, namely, the frequency decline in the frequency spectrum of an acoustic wave in water, was observed by measuring the frequency spectrum of acoustic streaming in a standing wave field. We desire that relations of the energy epsilon and momentum mu of acoustic waves analogous to those under quantum conditions hold, that is, epsilon =n(p)h(omega), mu=n(p)h(k), where h=h/2pi (h is Planck's constant), n(p) is the phonon density, omega is the angular frequency, and k is the wave number. In this case, a redshift indicates that acoustic waves suffer energy loss or annihilation of phonons. We show that the driving force of streaming is derived from the momentum transfer of phonons and the direct conversion of energy from acoustic energy to kinetic energy of the medium.
ABSTRACT
The acoustically agitated bubble oscillation in liquids that is considered to be related to the half-subharmonic acoustic bubble oscillations is discussed in terms of parametric decay instability. At the frequency of about 40 kHz, the half-subharmonic bubble oscillation mode should be a surface bubble oscillation that does not easily emit acoustic waves into water and confines acoustic energy from longitudinal waves. The half-subharmonic bubble oscillation is the dominant mode that leads to parametric decay instability of bubble oscillations.
