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showing 10 items of 5424 documents
Design, Synthesis and Biological Evaluation of Novel Pyrazolo[1,2,4]triazolopyrimidine Derivatives as Potential Anticancer Agents
2021
Three novel pyrazolo-[4,3-e][1,2,4]triazolopyrimidine derivatives (1, 2, and 3) were designed, synthesized, and evaluated for their in vitro biological activity. All three compounds exhibited different levels of cytotoxicity against cervical and breast cancer cell lines. However, compound 1 showed the best antiproliferative activity against all tested tumor cell lines, including HCC1937 and HeLa cells, which express high levels of wild-type epidermal growth factor receptor (EGFR). Western blot analyses demonstrated that compound 1 inhibited the activation of EGFR, protein kinase B (Akt), and extracellular signal-regulated kinase (Erk)1/2 in breast and cervical cancer cells at concentrations…
Retracted Article: Differential detection and quantification of cyclic AMP and other adenosine phosphates in live cells
2017
A new naphthol-based rhodamine derivative (NpRD) has been developed for the selective and differential detection of adenosine 3′,5′-cyclic monophosphate (cAMP) and adenosine phosphates (APs) (ATP, ADP, and AMP) from other nucleotides. The simple detection and quantification of cAMP in human blood cells and in other samples based on the ‘turn on’ fluorescence properties of this chemosensor through colorimetry or fluorometry makes it unique for probable application in high throughput screening.
Ligands affecting silver antimicrobial efficacy on Listeria monocytogenes and Salmonella enterica
2013
Although silver is being extensively used in food or other applications as the key component to control microbial proliferation, many factors affecting its real potential are still unknown. In the present work, the presence of specific ligands or the contents in organic matter was correlated with silver speciation and its antibacterial performance. Silver was found to be only active in form of free silver ions (FSI). The presence of chloride ions produced an equilibrium of stable silver chloride complexes which were void of antimicrobial efficacy. However, even at relatively high concentrations of chlorides, a small fraction of FSI may still be present, producing a bactericidal effect with …
The effect of iron on the biodegradation of natural dissolved organic matter
2016
Iron (Fe) may alter the biodegradation of dissolved organic matter (DOM), by interacting with (DOM), phosphorus (P) and microbes. We isolated DOM and a bacterial community from boreal lake water and examined bacterial growth on DOM in laboratory experiments. Fe was introduced either together with DOM (DOM-Fe) or into bacterial suspension, which led to the formation of insoluble Fe-precipitates on bacterial surfaces (Fe coating). In the latter case, the density of planktonic bacteria was an order of magnitude lower than that in the corresponding treatment without introduced Fe. The association of Fe with DOM decreased bacterial growth, respiration, and growth efficiency compared with DOM alo…
Factors influencing axillary shoot proliferation and adventitious budding in cedar.
2005
We developed procedures for in vitro cloning of Cedrus atlantica Manetti and C. libani A. Rich explants from juvenile and mature plants. Explant size was one determinant of the frequency of axillary bud break in both species. Shoot tips and nodal explants mainly developed calli, whereas bud sprouting occurred in defoliated microcuttings cultured on a modified Murashige and Skoog medium without growth regulators. Isolation and continuous subculture of sprouted buds on the same medium allowed cloning of microcuttings from C. atlantica and C. libani seedlings and bicentennial C. libani trees, thus providing a desirable alternative for multiplying mature trees that have demonstrated superior ch…
Microscale magnesium distribution in shell of the Mediterranean mussel Mytilus galloprovincialis: An example of multiple factors controlling Mg/Ca in…
2019
Abstract Since magnesium concentration (Mg/Ca) in biogenic calcite is considered to reflect water temperature during precipitation, the magnesium-to‑calcium ratio has been examined as a proxy for water temperature in paleoclimate research, although factors other than temperature may also influence Mg/Ca in biogenic calcite, thereby introducing a potential bias in the relationship between Mg/Ca and temperature observed in inorganic systems. To better understand factors controlling Mg incorporation into the calcitic shells of bivalves, the distribution of Mg in the Mediterranean mussel Mytilus galloprovincialis was studied, being compared with ambient sea surface temperature (SST), shell grow…
Synthesis and biological evaluation of antimalarial and antileukemic activity of new C-10 modified artemisinin derivatives
2021
Abstract Several non-acetal artemisinin derivatives were synthesized and their antimalarial activity against chloroquine-resistant parasites as well as their antileukemic activity were investigated. The azide 10 was proved to have slightly better activity than the current antimalarial drugs such as artesunate and chloroquine. In addition, the azide 10 and the aldehyde 7 were found to be effective in decreasing cell proliferation in leukemia cells.
SF002-96-1, a new drimane sesquiterpene lactone from an Aspergillus species, inhibits survivin expression
2013
Survivin, a member of the IAP (inhibitor of apoptosis) gene family, is overexpressed in virtually all human cancers and is functionally involved in the inhibition of apoptosis, regulation of cell proliferation, metastasis and resistance to therapy. Because of its upregulation in malignancy, survivin has currently attracting considerable interest as a new target for anticancer therapy. In a screening of approximately 200 strains of imperfect fungi for the production of inhibitors of survivin promoter activity, a new drimane sesquiterpene lactone, SF002-96-1, was isolated from fermentations of an Aspergillus species. The compound inhibited survivin promoter activity in transiently transfected…
Isolation, identification and toxicological characterization of TSS 1, a new mycotoxin of the rosenane class.
1990
11-β-hydroxy-7-deoxy-rosenonolactone (TSS1), a product of the pathogenic fungusTrichothecium roseum (Moniliaceae) was isolated from culture medium extracts and completely described in its structure by spectroscopical methods.TSS 1 was classified as a representative of the lactone series of the rosenane class and as a structural isomer to Rosenololactone (1) and Rosololactone (2, 3).TSS1 showed toxic effects in the growth inhibition test toE coli (EC 50: lOμg/mL) andB subtil is (EC 50: 17μg/mL), inhibited fermentation of yeast (EC 50: 2.8μg/mL) and suppressed motility ofAnemia satina larvae (EC 50: 45/μg/mL).Rosenonolactone, the best known representative of that mycotoxin class, showed only …
Theory of nucleation and crystal growth of polymers in concentrated solutions
1974
ABSTRACT The process of crystallization in concentrated solutions depends strongly on the rate of crystallization and the rate of long range diffusion of the polymer chains. If the crystallization proceeds slowly compared to diffusion, this type of crystal nucleus will be formed for which the free energy of nucleation is smallest. By taking into account entropy effects which are characteristic for chain molecules one can show that the crystal with smallest free energy of nucleation is a crystal with almost regular chain folds on the surfaces. The influence of supercooling, concentration and molecular weight on the thickness and growth rate of such crystals is discussed. If the crystallizati…