Chemical transformation

The aims of the dissertation are: Isolation and purification of the main chemical constituents of the plant Centella asiatica (L.) Urban collected from various regions in Vietnam; synthesis of new derivatives of asiatic acid and madecassic acid obtained from C. asiatica.

27p capheviahe27 23-02-2021 34 3   Download

In order to set up a system for production of recombinant proteins using suspension cell culture of Nicotiana tabacum cv. Bright Yellow 2 (BY-2), in vitro culture and genetic transformation protocols of such cells were optimised at the laboratory of Plant Cell Biotechnology, Institute of Biotechnology.

10p tamynhan8 04-11-2020 9 1   Download

Compared to regressions obtained using the traditional logarithmic transformation method, the above regressions had a much better fit. The original biomass data of the sample trees were also used to calculate the proportion of total biomass apportioned to trunk, branches, leaves and roots.

13p tamynhan8 04-11-2020 13 1   Download

In our studies on the phytochemistry and biological activities of Croton tonkinensis Gagnep. (Euphorbiaceae) oriented by traditional medicine interesting biological activities of the plant were demonstrated in correlation with the ent-kaurane-type diterpenoid constituents. The high accumulation of the active principle ent-18-acetoxy-7
-hydroxykaur-16-en-15-one (1) led to our recent study on the chemical modification of this lead compound. In this paper the transformations of 1 into several derivatives by hydrolysis, acetylation, and oxydation were reported.

4p uocvong04 24-09-2015 42 4   Download

Polylactic acid is one of the most popular bioplastics used in recent years and it is often mixed with other polymers or chemicals to form polymer blend because polylactic acid is able to accelerate biodegradation of polymer blends. This paper presents some results of study on polymer blend based on polylactic acid (PLA) and ethylene-co-vinylacetate copolymer (EVA).

5p uocvong01 24-09-2015 92 9   Download

Amyloid deposits with Arg124 mutated TGFBI protein havebeen identified inautosomal dominant blindingcorneal dystrophies.We assessedin vitrothe mechanisms determin-ing TGFBI protein amyloid transformation involving mutations of Arg124.Eight peptides synthesized following the TGFBI protein sequence, centered on codon Arg124 holding the previously reported amyloidogenic mutations and the respective controls were studied.Cys124 andHis124 mutated peptide preparations contained significantly higher amounts of amyloid than the native peptide....

8p tumor12 22-04-2013 41 2   Download

Minichromosome maintenance proteins (Mcm) 2–7 play essential roles in eukaryotic DNA replication. Several reports have indicated the usefulness of Mcm proteins as markers of cancer cells in histopathological diagnosis. However, their mode of expression and pathophysiological significance in cancer cells remain to be clarified. We com-paredthe level of expressionofMcmproteins amonghuman HeLa uterine cervical carcinoma cells, SV40-transformed human fibroblast GM00637 cells andnormal human fibro-blastWI-38 cells....

13p tumor12 20-04-2013 30 2   Download

The folding of a 93-residue protein, the histidine-phospho-carrier protein ofStreptomyces coelicolor,HPr,hasbeen studied using several biophysical techniques, namely fluo-rescence, 8-anilinonaphthalene-1-sulfate binding, circular dichroism, Fourier transform infrared spectroscopy, gel filtration chromatography and differential scanning calori-metry. The chemical-denaturation behaviour of HPr, fol-lowed by fluorescence, CD and gel filtration, at pH 7.5 and 25
C, is described as a two-state process, which does not involve the accumulation of thermodynamically stable intermediates.

14p fptmusic 16-04-2013 55 4   Download

Growth factors, including fibroblast growth factor-2 (FGF-2) and transform-ing growth factor-b(TGF-b) regulate fibroblast function, differentiation and proliferation. S100A8 and S100A9 are members of the S100 family of Ca 2+ -binding proteins and are now accepted as markers of inflammation. They are expressed by keratinocytes and inflammatory cells in human⁄murine wounds and by appropriately activated macrophages, endothelial cells, epithelial cells and keratinocytesin vitro.

17p awards 06-04-2013 33 2   Download

Noncovalent binding of thioxylo-oligosaccharide inhibitors, methyl 4-thio-a-xylobioside (S-Xyl2-Me), methyl 4,4 II -dithio-a-xylotrioside (S-Xyl3-Me), methyl 4,4 II ,4 III -trithio-a-xylotetroside (S-Xyl4-Me), and methyl 4,4 II , 4 III ,4 IV -tetrathio-a-xylopentoside (S-Xyl5-Me), to three family 11 endo-1,4-b-xylanases from Trichoderma reesei(TRX I and TRX II) and Chaetomium thermophilum (CTX) was characterized using electrospray ionization Fourier transform ion cyclotron resonance (FT-ICR) MS and X-ray crys-tallography. ...

17p awards 06-04-2013 38 3   Download

The core structure of the lipopolysaccharide (LPS) isolated from a rough strain of the phytopathogenic bacterium Pseudomonas syringaepv.phaseolicola, GSPB 711, was investigated by sugar and methylation analyses, Fourier transform ion-cyclotron resonance ESI MS, and one- and two-dimensional 1 H-, 13 C- and 31 P-NMR spectroscopy. Strong alkaline deacylation of the LPS resulted in two core-lipid A backbone undecasaccharide pentakisphos-phates in the ratio
2.

0p awards 05-04-2013 38 2   Download

The cloning of two novel genes that encode cytokinin oxidase/dehydrogenase (CKX) in barley is described in this work. Transformation of both genes intoArabidopsisand tobacco showed that at least one of the genes codes for a functional enzyme, as its expression caused a cytokinin-deficient phenotype in the heterologous host plants. Addi-tional cloning of two gene fragments, and anin silicosearch in the public expressed sequence tag clone databases, revealed the presence of at least 13 more members of the CKXgene family in barley and wheat. ...

13p awards 05-04-2013 53 4   Download

During a search for cDNAs encoding plant sterol acyl-transferases, we isolated four full-length cDNAs fromAra-bidopsis thaliana that encode proteins with substantial identity with animal lecithin : cholesterol acyltransferases (LCATs). The expressionof one of these cDNAs,AtLCAT3 (At3g03310), invarious yeast strains resulted in the doubling of the triacylglycerol content.

13p awards 05-04-2013 39 4   Download

Ligand-induced oligomerization of receptors is a key step in initiating growth factor signaling. Nevertheless, complex biological responses often require additionaltrans-signaling mechanisms involving two or more signaling cascades. For cells of neuronal origin, it was shown that neurotrophic effects evoked by nerve growth factor or other neurotro-phins dependhighlyon the cooperativitywith cytokines that belong to the transforming growth factor b (TGF-b) superfamily.

12p dell39 03-04-2013 31 3   Download

A catalytic turnover of supercoiled DNA (scDNA) transformation medi-ated by topoisomerases leads to changes in the linking number (Lk) of the polymeric substrate by 1 or 2 per cycle. As a substrate of the topoisomeri-zation reaction it is chemically identical to its product; even a single catalytic event results in the quantum leap in the scDNA topology.

8p dell39 27-03-2013 33 4   Download

The EVI1 transcriptional repressor is critical to the normal development of a variety of tissues and participates in the progression of acute myeloid leu-kaemias. The repressor domain (Rp) was used to screen an adult human kidney yeast two-hybrid library and a novel binding partner designated ubiquitously expressed transcript (UXT) was isolated.

12p galaxyss3 21-03-2013 40 5   Download

Although one of the priorities in Alzheimer’s research is to clarify the fila-ment formation mechanism for the tau protein, it is still unclear how it is transformed from a normal structure in a neuron. To examine the linkage-dependent contribution of each repeat peptide (R1–R4) to filament forma-

11p media19 06-03-2013 33 2   Download

The ubiquitin–proteasome pathway is crucial for a variety of biological processes, including spermatogenesis. Ubiquitin C-terminal hydrolase-L1 (Uch-L1) is thought to associate with monoubiquitin to control ubiquitin levels. Here, we report the identification of Uch-L1 cDNA from the testis of the rice field eel, a natural sex reversal vertebrate, by using cDNA microarray analysis.

8p media19 05-03-2013 37 3   Download

Smad proteins are the cellular mediators of the transforming growth fac-tor-b superfamily signals. Herein, we describe the isolation of a fourth Smad gene from the helminthSchistosoma mansoni, a receptor-regulated Smad (R-Smad) gene termedSmSmad1B. The SmSmad1B protein is com-posed of 380 amino acids, and contains conserved MH1 and MH2 domains separated by a short 42 amino acid linker region.

19p media19 04-03-2013 32 1   Download

A platform based on hydrophilic interaction chromatography in combina-tion with Fourier transform mass spectrometry was developed in order to carry out metabonomics of Drosophila melanogasterstrains. The method was able to detect230 metabolites, mainly in the positive ion mode, after checking to eliminate false positives caused by isotope peaks, adducts and fragment ions.

12p viettel02 20-02-2013 40 2   Download