Pengaruh Suhu Pengukusan Terhadap Sifat Fisika Kimia Tepung Ikan Rucah

This research was aimed to determine the best steamed temperature and to determine the steamed effect on phsycochemical of trash fish. The research was conducted on June-July 2014 in fishery processing laboratory and fishery chemical laboratory Faculty of Fisheries and Marine Science Riau University, and this research was conducted also in food laboratory Bogor Agriculture Institute. Trash fish was obtained from Tanjung Beringin Village, Rampah - North Sumatera. The metode used in this research was completely randomized design (CRD) with 3 treatments of steamed temperature S1 (100 ºC), S2 (90 ºC) and S3 (80 ºC).The results showed that the treatment S3 (80 ºC) of steamed temperature was the best treatment with absorption 126.67, white degree 33.67, pH 6.41 and yield 16.90. Chemical characteristic for ash content 17.72 %, water content 7.51%, protein content 50.95%, fat content 7.70 % and crude fiber 4.22%

Комплексоутворення калікс[4]аренгідроксиметил-фосфонової кислоти з триптофаном та N-aцетил-триптофанамідом

The Host-Guest complexation of calixarene hydroxymethylphosphonic acid with tryptophan and N-acetyltryptophan amide has been investigated by the RP HPLC method in H2O/MeCN (99/1) solution (column support Hypersil CN, UV-detector, λ = 254 nm). Adsorption of calixarene hydroxymethylphosphonic acid on the Hypersil CN surface has been studied. It has been found that hydroxymethylphosphonic acid is characterized by reversible sorption on the Hypersil CN surface. The binding constants (KA = 23000 M-1 and 39000 M-1 for tryptophan and N-acetyltryptophan amide, respectively) of the supramolecular complexes have been calculated from the ratio between the capacity factors k’ of the Guest and the calixarene hydroxymethylphosphonic acid Host concentration in the mobile phase. The Gibbs free energies of the tryptophan and N-acetyltryptophan amide complexes are -24.84 and -26.15 kJ/mol, respectively. The molecular modelling of calixarene hydroxymethylphosphonic acid and its complexes with tryptophan and N-acetyltryptophan amide (Hyper Chem, version 8, force field PM3) has indicated that the complexes are stabilized by hydrogen bonds, electrostatic, π-π, and solvatophobic interactions. The geometric parameters of the energy minimized calixarene macrocycle and its complexes with tryptophan and N-acetyltryptophan amide have been calculated. According to the calculations it has been shown that the Host-Guest complexation does not change the flattened-cone conformation of calixarene. Finally, the inverse correlation has been found between the KA values of the complexes and the Log P values of the guest molecules.Методом ОФ ВЭЖХ исследован процесс комплексообразования типа Хозяин-Гость каликсаренгидроксиметилфосфоновой кислоты с триптофаном и N-aцетил-триптофанамидом в растворе H2O/MeCN (99/1) (насадка Hypersil CN, УФ-детектор, λ = 254 нм). Исследовано взаимодействие каликсаренгидроксиметилфосфоновой кислоты с поверхностью хроматографической насадки Hypersil CN. Установлено, что каликсаренгидроксиметилфосфоновая кислота характеризуется обратимой сорбцией на поверхности Hypersil CN. Константы связывания супрамолекулярных комплексов (23000 M-1 и 39000 M-1 для триптофана и N-aцетилтриптофанамида, соответственно) были рассчитаны из соотношения меж- ду коэффициентом емкости k’ молекулы Гостя и концентрацией каликсаренгидроксиметилфосфо­новой кислоты Хозяина в подвижной фазе. Значения свободных энергий Гиббса комплексов каликса­ренгидроксиметилфосфоновой кислоты с триптофаном и N-aцетил-триптофанамидом составили -24.84 и -26.15 кДж/моль, соответственно. Проведено молекулярное моделирование каликсаренгидрокси- метилфосфоновой кислоты и ее комплексов с триптофаном и N-aцетилтриптофанамидом (Hyper Chem, версия 8, силовое поле PM3). Отмечается, что супрамолекулярные комплексы могут стабилизироваться водородными связями, а также электростатическими, π-π, и сольватофобными взаимодействиями. Рассчитаны геометрические параметры энергетически минимизированных структур каликсаренгидроксиметилфосфоновой кислоты и ее комплексов с триптофаном и N-aцетилтриптофанамидом. Согласно расчетам показано, что процесс комплексообразования не меняет конформацию макроциклического остова каликсарена. Установлено, что значения KA повышаются со снижением Log P молекул Гостей.Методом ОФ ВЕРХ досліджено процес комплексоутворення типу Господар-Гість каліксаренгідрокси- метилфосфонової кислоти з триптофаном та N-aцетилтриптофанамідом у розчині H2O/MeCN (99/1) (насадка Hypersil CN, УФ-детектор, λ = 254 нм). Досліджено взаємодію каліксаренгідроксиметилфосфонової кислоти з поверхнею хроматографічної насадки Hypersil CN. Встановлено, що каліксаренгідроксиметилфосфонова кислота характеризується оберненою сорбцією на поверхні Hypersil CN. Кон- станти зв’язування супрамолекулярних комплексів (23000 M-1 і 39000 M-1 для триптофану і N-aцетилтриптофанаміду, відповідно) були розраховані із співвідношення між коефіцієнтом ємкості k’ молекули Гостя і концентрацією каліксаренгідроксиметилфосфонової кислоти Господаря в рухомій фазі. Значення вільних энергій Гіббса комплексів каліксаренгідроксиметилфосфонової кислоти з триптофаном і N-aце- тилтриптофанамідом складає -24.84 і -26.15 кДж/моль, відповідно. Здійснено молекулярне моделювання каліксаренгідроксиметилфосфонової кислоти і її комплексів з триптофаном і N-aцетилтриптофанамідом (Hyper Chem, версія 8, силове поле PM3). Супрамолекулярні комплекси можуть стабілізуватись водневими зв’язками, а також електростатичними, π-π, і сольватофобними взаємодіями. Розраховані геометричні параметри энергетично мінімізованих структур каліксаренгідроксиметилфосфонової кис- лоти та її комплексів з триптофаном і N-aцетилтриптофанамідом. Показано, що значення KA зрос­тають зі зниженням Log P молекул субстратів, а процес комплексоутворення не змінює конформації макроциклічного кістяка каліксарену

Non-coordinating anions assemble cyanine amphiphiles into ultra-small fluorescent nanoparticles

A non-coordinating anion, fluorinated tetraphenylborate, assembles specially designed cationic cyanine amphiphiles into 7–8 nm fluorescent nanoparticles that are >40-fold brighter than a single cyanine dye. This kind of anion, combining hydrophobic and electrostatic forces in aqueous media, constitutes promising building blocks in the self-assembly of functional nanomaterials

Intermolecular dark resonance energy transfer (DRET): Upgrading fluorogenic DNA sensing

The sensitivity of FRET-based sensing is usually limited by the spectral overlaps of the FRET donor and acceptor, which generate a poor signal-to-noise ratio. To overcome this limitation, a quenched donor presenting a large Stokes shift can be combined with a bright acceptor to perform Dark Resonance Energy Transfer (DRET). The consequent fluorogenic response from the acceptor considerably improves the signal-to-noise ratio. To date, DRET has mainly relied on a donor that is covalently bound to the acceptor. In this context, our aim was to develop the first intermolecular DRET pair for specific sensing of nucleic acid sequences. To this end, we designed DFK, a push-pull probe based on a fluorenyl π-platform that is strongly quenched in water. DFK was incorporated into a series of oligonucleotides and used as a DRET donor with Cy5-labeled complementary sequences. In line with our expectations, excitation of the dark donor in the double-labeled duplex switched on the far-red Cy5 emission and remained free of cross-excitation. The DRET mechanism was supported by time-resolved fluorescence measurements. This concept was then applied with binary probes, which confirmed the distance dependence of DRET as well as its potency in detecting sequences of interest with low background noise

Nucleic Acids Res

We have used surface plasmon resonance to investigate the nucleic acid binding properties of the core protein of hepatitis C virus, a disordered protein believed to chaperone the genomic RNA. It was previously shown that a peptide (peptide E) corresponding to the association of two basic clusters of core enhances the annealing and the dimerization of nucleic acid fragments derived from a stem loop (SL2) in the 3' untranslated region of the hepatitis C virus genome. However, strong aggregation of nucleic acids by core or peptide E in the excess of the latter precluded the characterization of their binding parameters up to now. By careful design of surface plasmon resonance experiments, we obtained accurate binding parameters for the interaction of peptide E with SL2-derived oligonucleotides of different lengths and sequences, in form of stem-loop, duplex or strand. Peptide E was found to bind in a salt dependent manner to all oligonucleotides assayed. Affinity data identify at least two binding modes, of which one is independent of sequence/structure, and the other is specific to the SL2 stem-loop fold. Stoichiometry data support a multi-motif binding model allowing formation of higher-order complexes. We propose that the modular binding mode demonstrated for structured RNA-binding proteins also applies to this disordered chaperone and is relevant to its activity

Wnt signaling is boosted during intestinal regeneration by a CD44-positive feedback loop

Enhancement of Wnt signaling is fundamental for stem cell function during intestinal regeneration. Molecular modules control Wnt activity by regulating signal transduction. CD44 is such a positive regulator and a Wnt target gene. While highly expressed in intestinal crypts and used as a stem cell marker, its role during intestinal homeostasis and regeneration remains unknown. Here we propose a CD44 positive-feedback loop that boosts Wnt signal transduction, thus impacting intestinal regeneration. Excision of Cd44 in Cd44$^{fl/fl}$;VillinCreER$^{T2}$ mice reduced Wnt target gene expression in intestinal crypts and affected stem cell functionality in organoids. Although the integrity of the intestinal epithelium was conserved in mice lacking CD44, they were hypersensitive to dextran sulfate sodium, and showed more severe inflammation and delayed regeneration. We localized the molecular function of CD44 at the Wnt signalosome, and identified novel DVL/CD44 and AXIN/CD44 complexes. CD44 thus promotes optimal Wnt signaling during intestinal regeneration

Nucleic Acids Res

The HIV-1 nucleocapsid protein (NCp7) is a nucleic acid chaperone required during reverse transcription. During the first strand transfer, NCp7 is thought to destabilize cTAR, the (-)DNA copy of the TAR RNA hairpin, and subsequently direct the TAR/cTAR annealing through the zipping of their destabilized stem ends. To further characterize the destabilizing activity of NCp7, we locally probe the structure and dynamics of cTAR by steady-state and time resolved fluorescence spectroscopy. NC(11-55), a truncated NCp7 version corresponding to its zinc-finger domain, was found to bind all over the sequence and to preferentially destabilize the penultimate double-stranded segment in the lower part of the cTAR stem. This destabilization is achieved through zinc-finger-dependent binding of NC to the G(10) and G(50) residues. Sequence comparison further revealed that C*A mismatches close to the two G residues were critical for fine tuning the stability of the lower part of the cTAR stem and conferring to G(10) and G(50) the appropriate mobility and accessibility for specific recognition by NC. Our data also highlight the necessary plasticity of NCp7 to adapt to the sequence and structure variability of cTAR to chaperone its annealing with TAR through a specific pathway

Photopolymerized micelles of diacetylene amphiphile: physical characterization and cell delivery properties:

A series of polydiacetylene (PDA) - based micelles were prepared from diacetylenic surfactant bearing polyethylene glycol, by increasing UV-irradiation times. These polymeric lipid micelles were analyzed by physicochemical methods, electron microscopy and NMR analysis. Cellular delivery of fluorescent dye suggests that adjusting the polymerization state is vital to reach the full in vitro potential of PDA-based delivery system