Isolation of gibberellins A3, A4 and A7 from Pinus attenuata pollen

Three native gibberellins of Pinus attenuata pollen, GA₃, GA₄ and GA₇ have been characterized by GC-MS and a fourth, less polar, GA with chromatographic characteristics similar to GA₉ was shown to be present. At least two other as yet unidentified, less polar GA-like substances are also present in the dormant and/or germinating pollen. The concentration of the GA₉-like substance, and of GA₄ and GA₇, decreases during germination, while peaks of biological activity of a more polar nature increase. The most predominant of the polar peaks present 15 hr after germination was GA₃.     

Zur Frage des Vorkommens der GattungTsuga im polnischen Interglazial

Ohne Zusammenfassung     

Isolation and characterization of polymorphic microsatellites for the bastard sole (Microchirus azevia)

The bastard sole (Microchirus azevia) is a species of commercial interest in Spain. Nevertheless, little information is currently available about the genetic characteristics of wild populations. In this survey, we have developed eight new microsatellites using an enriched genome library protocol. Primers were screened on a total of 54 individuals from two wild populations (Mediterranean and Atlantic) from the south coast of Spain, revealing six to 18 alleles per locus with expected heterozygosities ranging from 0.51 to 0.94. These markers can potentially be useful tools for use in population genetic studies.     

A DNA aptamer with high affinity and specificity for therapeutic anthracyclines

We describe the characterization of a DNA aptamer that displays high affinity and specificity for the anthracyclines daunomycin and doxorubicin, both of which are frequently used in chemotherapy. Aptamers were isolated from a pool of random sequences using a semiautomated procedure for magnetic beads. All selected aptamers displayed high affinity for the target molecule daunomycin. One aptamer was further characterized and exhibited a dissociation constant (KD) of 20 nM. To examine the aptamer's binding properties and clarify its applicability for diagnostic assays, its performance under various buffer conditions was evaluated. The aptamer proved to be very robust and not dependent on the presence of specific ions. It also tolerated a wide pH range and immobilization via 5'-biotinylation. Furthermore, a competition assay for sensitive daunomycin detection was established. This not only allows the determination of the aptamer's specificity but also allows the quantification of as little as 8.4 microg/L daunomycin and doxorubicin.     

Response surface method to optimize the production and characterization of lipase from Penicillium verrucosum in solid-state fermentation

Current studies about lipase production by solid-state fermentation involve the use of agro-industrial residues towards developing cost-effective systems directed to large-scale commercialization of enzyme-catalyzed processes. In this work, lipase production and partial characterization of the crude enzymatic extracts obtained by Penicillium verrucosum using soybean bran as substrate was investigated. Different inductors were evaluated and the results showed that there is no influence of this variable on the lipase production, while temperature and initial moisture were the main factors that affected enzyme production. The optimized cultivation temperature (27.5 °C) and initial moisture of substrate (55%) were determined using the response surface methodology. Kinetics of lipase production was followed at the optimized growth conditions. Optimum lipase yield was 40 U/g of dry bran. The crude enzymatic extract showed optimal activity in the range from 30 to 45 °C and in pH 7.0.     

A calibrated diversity assay for nucleic acid libraries using DiStRO—a Diversity Standard of Random Oligonucleotides

We have determined diversities exceeding 10¹² different sequences in an annealing and melting assay using synthetic randomized oligonucleotides as a standard. For such high diversities, the annealing kinetics differ from those observed for low diversities, favouring the remelting curve after annealing as the best indicator of complexity. Direct comparisons of nucleic acid pools obtained from an aptamer selection demonstrate that even highly complex populations can be evaluated by using DiStRO, without the need of complicated calculations.     

12 Reconstructing the RNA world

A critical event in the origin of life is thought to have been the emergence of an RNA molecule capable of self-replication as well as mutation, and hence evolution towards ever more efficient replication. As this primordial replicase appears to have been lost in time, we use synthetic biology to build modern-day “Doppelgangers” of the ancestral replicase to reconstruct and study their properties in an effort to learn more about life’s first genetic system. I will discuss our progress in the engineering and evolution of RNA polymerase ribozymes as well as the potential role that structured media such as the eutectic phase of water–ice may have played in the emergence of RNA self-replication.     

Systematic coordination chemistry and cytotoxicity of copper(II) complexes with methyl substituted 4-nitropyridine N-oxides

Three new nitrato copper(II) complexes of dimethyl substituted 4-nitropyridine N-oxide were synthesized and characterized by elemental analysis, magnetic, spectroscopic, thermal and X-ray methods, respectively. They were isolated as trans isomers, mononuclear (μ = 1.70-1.88 BM), five (1-2) and four (3) coordinate species of general formula [Cu(NO₃)₂(H₂O)L₂] where L = 2,3-dimethyl-, 2,5-dimethyl-4-nitropyridine N-oxide and [Cu (NO₃)₂L₂], L = 3,5-dimethyl-4-nitropyridine N-oxide, respectively. The X-ray crystal structure of (1) (L = 2,3-dimethyl-4-nitropyridine N-oxide) was determined. The organic ligands, the complexes and copper hexaqua ion as a reference were tested in vitro on the cytotoxic activity against human cancer cell lines: MCF-7 (breast), SW-707 (colon) and P-388 (murine leukemia). The complexes are relatively strong cytotoxic agents towards P-388 cell line. Comparative analysis was performed for all known copper(II) complexes containing methyl derivatives of the 4-nitropyridine N-oxide on the basis of their composition, structure and cytotoxic activities. To obtain the typical structure for these species (i.e., 4-coordinate mononuclear of the type trans-[Cu(inorganic anion)₂L₂]), two methyl groups must be situated on both sides of nitrogen atom(s) (i.e., NO and NO₂) in the ligand. The biological activity was found to be strongly dependent upon the number of the methyl groups and the type of cell line. The best cytotoxic results were found for the complexes without substituents or with one methyl group. Generally, for all cell lines, the complexation increased cytotoxicity when compared with the free ligands.