Potato transformation byAgrobacterium rhizogenes Ri plasmid

Potato root cultures transformed by_pRiA4 T-DNA do not regenerate plants in vitro spontaneously, but regeneration can be induced by a sequence of callogenesis and regeneration media. Both T_l and T_r-DNA were found by Southern blotting. Regenerated transformants showed characteristic morphological deviations in the in_vitro cultures. Plants in the soil showed differences in the inflorescence and tuber development.     

Gold nanoparticles and electromagnetic irradiation in tissue culture systems of bleeding heart: biochemical,physiological, and (cyto)genetic effects

Plant Cell, Tissue and Organ Culture (PCTOC) - This study aimed to analyze the effect of various mutagens on the in vitro development, physiological activity, acclimatization efficiency, and...     

Species richness of plants and fungi in western Panama: towards a fungal inventory in the tropics

In order to document the species richness of plants and fungi in a tropical area, a trail of 500?m in tropical lowlands in the Chiriquí province, on the Pacific side of western Panama, was sampled each month during 2?years with 2?h dedicated to plants and 2?h dedicated to fungi, each by two botanists or mycologists respectively. The 24 sampling events yielded approximately 4,000 records of plants corresponding to 311 species as well as 1,614 records of fungi corresponding to approximately 567 species. Lists of more or less certain names of plants and fungi as well as voucher specimens are provided. The randomized species accumulation curve for plants approaches an asymptote and estimators yield stable values of 310–318 predicted plant species in the area of investigation. The curve for records of fungal species, however, did not saturate and all applied estimator functions failed to predict the total richness of fungi for the area convincingly. Two plant collections correspond to new records for Panama and 54 species and infraspecific taxa are new for the Chiriquí province. The identification of fungi is still in process and yielded two species probably new to science as well as 17 new records of species for Panama to date. In order to assess biodiversity patterns (e.g. fungi to plant ratios) of tropical fungi more accurately, it is necessary to repeat such investigations in other areas and to improve the tools for taxonomic identification of these highly diverse but mostly microscopic organisms.     

Responsive polymer systems for controlled delivery of therapeutics.

The ideal drug-delivery system should provide therapeutics in response to physiological requirements, having the capacity to 'sense' changes and alter the drug-release process accordingly. Such responsive controlled delivery systems are still at an experimental stage. This review focuses on two basic approaches: (1) externally regulated systems (utilizing triggers such as magnetism, ultrasound, temperature and electricity), and (2) self-regulated systems (utilizing pH-sensitive polymers, enzyme-substrate reactions, competitive binding, and antibody interactions).     

Dominance‐related changes in spatial memory are associated with changes in hippocampal cell proliferation rates in mountain chickadees

It is well established that spatial memory is dependent on the hippocampus in both mammals and birds. As memory capacity can fluctuate on a temporal basis, it is important to understand the mechanisms mediating such changes. It is known that early memory‐dependent experiences in young animals result in hippocampal enlargement and in increased neurogenesis, including cell proliferation and neuron survival. It is less clear, however, whether temporal changes in spatial memory are also associated with changes in hippocampal anatomy and cell proliferation in fully grown and experienced adult animals. In a previous study, we experimentally demonstrated that socially subordinate mountain chickadees (Poecile gambeli) showed inferior spatial memory performance compared to their dominant group mates, in the absence of significant differences in baseline corticosterone levels. Here we investigated whether these differences in memory between dominant and subordinate birds were associated with changes in the hippocampus. Following memory tests, chickadees were injected with 5‐bromo‐2′‐deoxyuridine to label dividing cells and sacrificed 2 days after the injections. We found no significant differences in volume or the total number of neurons in the hippocampal formation between dominant and subordinate chickadees, but subordinate birds had significantly lower cell proliferation rates in the ventricular zone adjacent to both the hippocampus and mesopallium compared to the dominants. Individuals, which performed better on spatial memory tests tended to have higher levels of cell proliferation. These results suggest that social status can affect cell proliferation rates in the ventricular zone and support the hypothesis that neurogenesis might be involved in memory function in adult animals. © 2004 Wiley Periodicals, Inc. J Neurobiol, 2005     

Ploidy-dependent survival of progeny arising from crosses between natural allotriploid Cobitis females and diploid C. taenia males (Pisces,Cobitidae)

Crosses between 21 triploid hybrid Cobitis females and 19 C. taenia (2n = 48) males led to viable progeny; whereas no embryonic development was observed in crosses with tetraploid males (4n = 98). The ploidy status of 491 progenies randomly selected with flow cytometry (316) or chromosome analysis (175) revealed an average of 55.2 % triploids and 44.8 % tetraploids, but the ratio of 3n versus 4n fish did change during development. In the first 2 days after hatching, approximately 65.1 % of tetraploid larvae were observed. Their number decreased significantly to 30.8 and 6.2 % on average during 2–5 and 10–15 months of life, respectively. The karyotype of tetraploid progeny (4n = 98) included 3n = 74 chromosomes of the parental female and n = 24 of C. taenia male. The number of tetraploid progeny indicated indirectly that about 66 % of eggs from 3n females were fertilized with C. taenia. The rest of the eggs developed clonally via gynogenesis or hemiclonally via hybridogenesis into triploids of the same karyotype structure as parental females. We have documented for the first time that (at least under experimental conditions) tetraploids are commonly formed, but are less viable than triploids, and a ratio similar to what is found under natural conditions is finally attained. The current explanation concerning the ploidy and karyotype structure of the progeny confirms that the eggs of 3n Cobitis females are not only capable of maintaining all chromosomes but are also capable of incorporating the sperm genome, thus creating the potential to produce tetraploids.     

Heavy and light forms of some aminoacyl-tRNA synthetases in fraction X,microsomes and cytosol of rabbit liver

Summary Aminoacyl-tRNA synthetase activity for alanine, glutamic acid, lysine and phenylalanine was studied in the three subcellular fractions of rabbit liver: fraction X, microsomes and cytosol. From 60 to 80% of the enzyme activities were found in fraction X and microsomes. Fraction X was especially rich in the synthetase activities. By means of gel chromatography, heavy (over 10⁶ daltons) and light (below 480 × 10³ daltons) forms of lysyl- and phenylalanyl- but only light ones of alanyl- and glutamyl-tRNA synthetase activities were found in all the subcellular fractions studied. It is concluded that in higher organisms (mammals) all aminoacyl-tRNA synthetases, at least in part, are associated with cell structural constituents.Abbreviations ALA, GLU, LYS, PHE alanyl-, glutamyl-, lysyl-, phenylalanyl-tRNA synthetase - PMSF phenylmethylsulfonyl fluoride - BSA bovine serum albumin     

Microwave‐assisted 18O labeling of Fmoc‐protected amino acids

Recently, there has been an increased interest in isotopical labeling of peptides. Although there are several techniques allowing for a complete labeling of all carboxyl groups in peptides, regioselective labeling would be beneficial in many situations. Such labeling requires the use of ¹⁸O‐labeled Fmoc amino acids. We have designed a method for such labeling that is an improvement on a technique proposed earlier. The new procedure is suitable for microscale synthesis and could be used in peptide and proteomics laboratories. Although for the majority of tested amino acids our method gives good labeling efficiency, it is time consuming. Therefore, we have decided to use microwave‐assisted procedure. This approach resulted in reduction of reaction time to 15 min and increased reaction efficiency. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.     

A Comparative Study of Nitrilases Identified by Genome Mining

Escherichia coli strains expressing different nitrilases transformed nitriles or KCN. Six nitrilases (from Aspergillus niger (2), A. oryzae, Neurospora crassa, Arthroderma benhamiae, and Nectria haematococca) were arylacetonitrilases, two enzymes (from A. niger and Penicillium chrysogenum) were cyanide hydratases and the others (from P. chrysogenum, P. marneffei, Gibberella moniliformis, Meyerozyma guilliermondi, Rhodococcus rhodochrous, and R. ruber) preferred (hetero)aromatic nitriles as substrates. Promising nitrilases for the transformation of industrially important substrates were found: the nitrilase from R. ruber for 3-cyanopyridine, 4-cyanopyridine and bromoxynil, the nitrilases from N. crassa and A. niger for (R,S)-mandelonitrile, and the cyanide hydratase from A. niger for KCN and 2-cyanopyridine.