Synthesis of novel d-glucuronic acid fatty esters using Candida antarctica lipase in tert-butanol

Glucuronic acid n-alkyl esters, a novel class of promising biosurfactants and their corresponding glucose esters with the same side-chain length, were synthesized by direct esterification in a non-aqueous phase (tert-butanol) using an immobilized lipase.     

Enzymatic hydrolysis of cyanohydrins with recombinant nitrile hydratase and amidase from hodococcus erythropolis

Nitrile hydratase and amidase from Rhodococcus erythropolis CIMB11540 were both cloned and expressed in Escherichia coli. Crude cell free extracts were used for the hydrolysis of different aromatic cyanohydrins. Nitrile hydratase expression was increased up to 5-fold by redesign of the expression cassette. The recombinant enzymes were successfully used for the conversion of several cyanohydrins to the corresponding alpha-hydroxy amides and acids while retaining enantiopurity.     

Somatic embryogenesis in Centella asiatica L. an important medicinal and neutraceutical plant of India

Leaf segments excised from Centella asiatica, a medicinal and neutraceutical plant, produced abundant somaticembryoswhen cultured onMS mediumwith 9.29 Mkinetin in combination with 2.26 M2,4-D. Granular, white,shiny clusters of callus developed after 1 week of culture, and then formed heart and cotyledonary stage embryoson the same medium after 4 weeks. Somatic embryos matured and germinated in the presence of MS mediumcontaining 2.32 M kinetin with (2.89M) GA3. Plantlets were successfully transferred to pots containing amixture of soil and vermiculite (1:1).     

Absence of intrinsic electric conductivity in single dsDNA molecules

The intrinsic dc conductivity of long, individual lambda phage dsDNA molecules has been investigated by ultrasensitive low current-voltage-spectroscopy (IV) under ambient conditions and controlled low humidity inert gas atmosphere on microfabricated metal-insulator-metal gap structures. We found a strong dependence of the measured conductivity on the apparent humidity, which we attribute to capillary condensation of water to the immobilized DNA molecules, giving rise to additional ionic currents. Additional IV-spectroscopy experiments under controlled argon atmosphere always revealed a significant drop in electrical conductivity to 4 x 10(-15)AV(-1)microm(-1), indicating almost no considerable contribution of electrical long range charge transport.     

Plant wounding affects the oviposition of Hellula undalis(F.). The impact of leaf chemistry

Crucifer specialists, such as the tropical pest Hellula undalis (F.), developed a close association to their hosts and depend on characteristic secondary plant compounds, the glucosinolates (GS), in many cases. Following tissue damage, GS undergo hydrolysis catalyzed by the enzyme myrosinase to produce a complex array of products which include isothiocyantes, cyanides, and thiocyanates depending on reaction condition and the chemical nature of the side chain. We found that mechanical plant damage to the tropical crop plant Brassica campestris L. ssp. chinensis (pak-choi) leads to increased GS content, especially of indolyl GS and affected the oviposition behaviour of H. undalis negatively. GS were detected in methanolic leaf surface extracts from intact B chinensis and Sinapis alba (L.) plants, but no hydrolysis products of GS were found in leaf extracts with methylene chloride. Furthermore, the oviposition stimulant activity of GS extracts for H. undalis was greatly reduced after hydrolysis of GS by myrosinase. These results suggest the importance of GS for inducing oviposition, thus excluding hydrolysis products as active principle. Specific produced slightly volatile hydrolysis products of GS (3-indolylmethyl-cyanide and 5-vinyloxazolidine-2-thione) reduced oviposition, when applied to the host-plant. Leaf chemistry, including volatile and non-volatile compounds, may determine oviposition in H. undalis indicating a suitable host-plant.     

Inhibition of the p53-hdm2 interaction with low molecular weight compounds

The hdm2 protein, upon binding to p53, inhibits its tumor suppressor activity. The inhibition of the p53-hdm2 interaction represents therefore a new therapeutic strategy to activate wild type p53 in tumors. Potent low molecular weight compounds inhibiting this protein-protein interaction, which are active in vivo, have just been identified. This offers new perspectives and hopes in this research area.     

Intraoperative isolation and processing of BM-derived stem cells

To improve tissue regeneration of ischemic myocardium, autologous bone marrow-derived stem cells have been injected intramyocardially in five patients undergoing coronary artery bypass grafting and transmyocardial laser revascularization. An innovative method for the intraoperative isolation of CD133(+)-stem cells in less than 3 hours has been established. After induction of general anesthesia, approx. 60-240 ml of bone marrow were harvested from the posterior iliac crest and processed in the operating room under GMP conditions using the automated cell selection device Clini-MACS. Following standard CABG surgery, LASER channels were shot in predefined areas within the hibernating myocardium. Subsequently, autologous CD133(+)-stem cells (1.9-9.7 x 10(6) cells; purity up to 97%) were injected in a predefined pattern around the laser channels. Through the intraoperative isolation of CD133(+)-cells, this effective treatment of ischemic myocardium can be applied to patients scheduled both for elective and for emergency revascularisation procedures.     

Effects of vestibular and support afferentation upon visual pursuit in microgravity

Evaluation of the accuracy of eye turns (saccades) to fix a jerky pointed stimulus, and smooth pursuit of slow linear and sinusoidal movements of both pointed and optokinetic stimuli was performed in 31 cosmonauts on flight days 2-3, 5-8, 30, and once in one or two months of mission. An additional investigation of the eye pursuit function involved 10 cosmonauts, who, after testing during free floating, fulfilled stimulus tracking following a cycle of active head rotation, and 14 cosmonauts who received support afferentation. It was found that at the beginning of adaptation and periodically in the course of long mission, the systems of slow pursuit tracking adopted the strategy of saccadic approximation whereby gaze fixation was achieved through a sequence of macro- or microsaccadic movements. It was demonstrated that these disturbances, practically in all investigated cosmonauts, were consequent to the vestibular deprivation developing in microgravity. Vestibular afferentation produced by active head rotation improved characteristics of visual pursuit. Support deprivation also affects pursuit tracking by cosmonauts who form the concept of space orientation based on perception of their head and leg position. With support afferentation, these cosmonauts demonstrated improved visual pursuit characteristics.     

Involvement of Ca2+/calmodulin-dependent protein kinase II in endothelial NO production and endothelium-dependent relaxation

Nitric oxide (NO) is synthesized from l-arginine by the Ca(2+)/calmodulin-sensitive endothelial NO synthase (NOS) isoform (eNOS). The present study assesses the role of Ca(2+)/calmodulin-dependent protein kinase II (CaMK II) in endothelium-dependent relaxation and NO synthesis. The effects of three CaMK II inhibitors were investigated in endothelium-intact aortic rings of normotensive rats. NO synthesis was assessed by a NO sensor and chemiluminescence in culture medium of cultured porcine aortic endothelial cells stimulated with the Ca(2+) ionophore A23187 and thapsigargin. Rat aortic endothelial NOS activity was measured by the conversion of l-[(3)H]arginine to l-[(3)H]citrulline. Three CaMK II inhibitors, polypeptide 281-302, KN-93, and lavendustin C, attenuated the endothelium-dependent relaxation of endothelium-intact rat aortic rings in response to acetylcholine, A23187, and thapsigargin. None of the CaMK II inhibitors affected the relaxation induced by NO donors. In a porcine aortic endothelial cell line, KN-93 decreased NO synthesis and caused a rightward shift of the concentration-response curves to A23187 and thapsigargin. In rat aortic endothelial cells, KN-93 significantly decreased bradykinin-induced eNOS activity. These results suggest that CaMK II was involved in NO synthesis as a result of Ca(2+)-dependent activation of eNOS.     

X-Ray Analysis of the Magnesium-containing Endonuclease from Serratia marcescens

The three-dimensional crystal structure of the DNA/RNA nonspecific endonuclease from Serratia marcescenswas refined at the resolution of 1.07 Å to Rfactor of 12.4% and R _freefactor of 15.3% using the anisotropic approximation. The structure includes 3924 non-hydrogen atoms, 715 protein-bound water molecules, and a Mg²⁺ion in each binding site of each subunit of the nuclease homodimeric globular molecule. The 3D topological model of the enzyme was revealed, the inner symmetry of the monomers in its N-and C-termini was found, and the local environment of the magnesium cofactor in the nuclease active site was defined. Mg²⁺ion was found to be bound to the Asn119 residue and surrounded by five associated water molecules that form an octahedral configuration. The coordination distances for the water molecules and the O¹atom of Asn119 were shown to be within the range of 2.01–2.11 Å. The thermal factors for the magnesium ion in subunits are 7.08 and 4.60 Ų, and the average thermal factors for the surrounding water molecules are 11.14 and 10.30 Ų, respectively. The region of the nuclease subunit interactions was localized, and the alternative side chain conformations were defined for 51 amino acid residues of the nuclease dimer.