Phytoene production utilizing the isoprenoid biosynthesis capacity of Thermococcus kodakarensis

Phytoene (C₄₀H₆₄) is an isoprenoid and a precursor of various carotenoids which are of industrial value. Archaea can be considered to exhibit a relatively large capacity to produce isoprenoids, as they are components of their membrane lipids. Here, we aimed to produce isoprenoids such as phytoene in the hyperthermophilic archaeon Thermococcus kodakarensis. T. kodakarensis harbors a prenyltransferase gene involved in the biosynthesis of farnesyl pyrophosphate and geranylgeranyl pyrophosphate, which are precursors of squalene and phytoene, respectively. However, homologs of squalene synthase and phytoene synthase, which catalyze their condensation reactions, are not found on the genome. Therefore, a squalene/phytoene synthase homolog from an acidothermophilic archaeon Sulfolobus acidocaldarius, Saci_1734, was introduced into the T. kodakarensis chromosome under the control of a strong promoter. Production of the Saci_1734 protein was confirmed in this strain, and the generation of phytoene was detected (0.08–0.75 mg L⁻¹ medium). We then carried out genetic engineering in order to increase the phytoene production yield. Disruption of an acetyl-CoA synthetase I gene involved in hydrolyzing acetyl-CoA, the precursor of phytoene, together with the introduction of a second copy of Saci_1734 led to a 3.4-fold enhancement in phytoene production.

     

ERRγ Preserves Brown Fat Innate Thermogenic Activity

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Primary Cilium-Mediated Retinal Pigment Epithelium Maturation Is Disrupted in Ciliopathy Patient Cells

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Influence of a developing tree canopy on the yield of Pennisetum pedicellatum sown on a mine spoil

Abstract. Shoot and root biomass yield of a sown grass, Pennisetum pedicellatum, were measured at below-canopy, canopy edge and open locations in young monoculture stands of eight tree species planted on a coalmine spoil. Incident light as percentage of full sunlight decreased from open to canopy edge to below-canopy locations. The shoot and root weights of Pennisetum in different tree stands for each of the three locations were significantly different and were significantly related to each other, and to percentage sunlight across all tree species plots and locations. The gradient of incident light was the principal factor governing the gradient of grass biomass under developing canopies of tree plantations on the mine spoil.     

Metal(II) complexes of 1-formylisoquinoline thiosemicarbazone: their preparation,characterization and antitumour activity

Complexes of Co(II), Ni(lI), Cu(II), Zn(II) and Pt(II) with 1-formylisoquinoline thiosemicarbazone (1-iqtsc-H) were prepared and characterized by elemental analyses, conductance measurement and spectral studies. On the basis of these studies a distorted octahedral structure for [Co(1-iqtsc)₂]·2H₂O, a distorted trigonal-bipyramidal structure for [Ni- (1-iqtsc-H)Cl₂], [Cu(1-iqtsc-H)Cl₂] and [Zn(1-iqtsc- H)(OAc)₂]·H₂O and a square-planar structure for [Pt(1-iqtsc)Cl] are suggested. All these metal(II) complexes were screened for their antitumour activity in the P388 lymphocytic leukaemia test system in mice. Except for Pt(Il), the complexes were found to possess significant activity; the Ni(II) complex showed a T/C value of 161 at the optimum dosage.     

Antifungal activity of soybean and chickpea isoflavones and their reduced derivatives

The fungicidal activity of the isoflavones from soybean (Glycine max) and chickpea (Cicer arietinum) has been studied on three food and forage contaminating fungi, Aspergillus ochraceus, Penicillium digitatum and Fusarium culmorum. The reduced derivatives of the corresponding isoflavones—the isoflavanones and the isoflavans—were also included in the investigation. For the first time in a comparative study it is shown that isoflavones and isoflavanones are variable in their activity whereas the isoflavans are moderately active inhibitors of fungal growth.     

Polypeptide motions are dominated by peptide group oscillations resulting from dihedral angle correlations between nearest neighbors

To identify basic local backbone motions in unfolded chains, simulations are performed for a variety of peptide systems using three popular force fields and for implicit and explicit solvent models. A dominant "crankshaft-like" motion is found that involves only a localized oscillation of the plane of the peptide group. This motion results in a strong anticorrelated motion of the phi angle of the ith residue (phi(i)) and the psi angle of the residue i - 1 (psi(i-1)) on the 0.1 ps time scale. Only a slight correlation is found between the motions of the two backbone dihedral angles of the same residue. Aside from the special cases of glycine and proline, no correlations are found between backbone dihedral angles that are separated by more than one torsion angle. These short time, correlated motions are found both in equilibrium fluctuations and during the transit process between Ramachandran basins, e.g., from the beta to the alpha region. A residue's complete transit from one Ramachandran basin to another, however, occurs in a manner independent of its neighbors' conformational transitions. These properties appear to be intrinsic because they are robust across different force fields, solvent models, nonbonded interaction routines, and most amino acids.     

Genetic characterization of chayote [<Emphasis Type="Italic">Sechium edule</Emphasis> (Jacq.) Swartz.] landraces of North Eastern Hills of India and conservation measure

Chayote or chow–chow is an underutilized cucurbit vegetable crop, widely cultivated by farmers in the backyards and Jhum lands for its tender leaves, fruits and tuberous root. In order to initiate crop improvement program in this crop, the present study was undertaken to assess the genetic variations in the 74 chow–chow landraces collected from the North Eastern Hill region of India. Wide variations for fruit colors, fruit length (6.5–21.5 cm), fruit width (4.2–10.7 cm), fruit weight (60–560 g), vitamin-C (2.6–13.8 mg/100 g), reducing sugar (0.18–2.77%), total sugar (1.09–2.94%) and phenol content (0.17–3.85 mg/100 g FW) were recorded among the landraces. All the landraces were also characterized using random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) markers. In RAPD analyses, out of 28 primers a total of 198 reproducible amplicons were formed at an average of 7.01 per primer and an overall polymorphism of 88.38%. Eight fragments were specific to landraces with light green fruits. Four fragments were observed to be specific to RCSC-22 (dark green fruits) and another four specific to a RCSC-30 (pale yellow fruits). Out of 30 ISSR, only 5 primers generated a total of 32 reproducible amplicons with an average of 6.4 per primer and overall polymorphism of 62.5%. The pair wise similarity coefficient values ranged from 0.55 to 0.96. The grouping of landraces in cluster analysis was found to be independent of their respective geographic locations. The cuttings of suckers and shoot top (2 months old) treated with indole-3-butyric acid (200 mg l^?1) provide an alternative for the conservation of the diverse genetic materials to the researchers.     

Analysis of fatty acid composition of PGPR <Emphasis Type="Italic">Klebsiella</Emphasis> sp. SBP-8 and its role in ameliorating salt stress in wheat

A halotolerant plant-growth-promoting rhizobacteria (PGPR) can ameliorate salt stress in associated plants by various mechanisms. Therefore, the present study aimed to characterize a PGPR Klebsiella sp. SBP-8 for its ability to tolerate salt stress and to study the mechanism of PGPR-mediated mitigation of salt stress in the wheat plant. The abiotic stressors result in multiple changes in the fatty acid composition of Klebsiella sp. SBP-8, helping the membrane to keep its integrity, fluidity, and function for its growth under salt (NaCl) stress conditions. The changes in fatty acid composition of test organism were analyzed by fatty acid methyl ester (FAME) analysis under varying saline conditions. The spectroscopy (GC-MS) profile of cell extract at different salt concentrations was comprised of hydrocarbons, and fatty alcohols with varying carbon chain length. Inoculation of Klebsiella sp. SBP-8 to wheat seedling showed increase in proline, total soluble sugar, and total protein content of treated plants. Bacterial inoculation also decreased the concentration of salinity-induced malondialdehyde (MDA) content. In addition, bacterial inoculation also increased the various antioxidative enzymes like superoxide dismutase (SOD), catalase (CAT), and peroxidase (POX) in treated plants. It is likely that bacterial inoculation alleviated the salt stress to wheat plant by co-ordination of antioxidative machinery, and improvement in osmolyte contents. Therefore, the present study suggests that bacterial-inoculated wheat plants were able to cope better with salt stress than uninoculated control, therefore it can serve as a promising bio-inoculant for enhancing the growth of wheat like cereal crops under saline stress.