Kinetics of medium-chain-length polyhydroxyalkanoate production by a novel isolate of Pseudomonas putida LS46

Six bacteria that synthesize medium-chain-length polyhydroxyalkanoates (mcl-PHAs) were isolated from sewage sludge and hog barn wash and identified as strains of Pseudomonas and Comamonas by 16S rDNA gene sequencing. One isolate, Pseudomonas putida LS46, showed good PHA production (22% of cell dry mass) in glucose medium, and it was selected for further studies. While it is closely related to other P.?putida strains (F1, KT2440, BIRD-1, GB-1, S16, and W619), P.?putida LS46 was genetically distinct from these other strains on the basis of nucleotide sequence analysis of the cpn60 gene hypervariable region. PHA production was detected as early as 12?h in both nitrogen-limited and nitrogen-excess conditions. The increase in PHA production after 48?h was higher in nitrogen-limited cultures than in nitrogen-excess cultures. Pseudomonas?putida LS46 produced mcl-PHAs when cultured with glucose, glycerol, or C(6)-C(14) saturated fatty acids as carbon sources, and mcl-PHAs accounted for 56% of the cell dry mass when cells were batch cultured in medium containing 20?mmol/L octanoate. Although 3-hydroxydecanoate was the major mcl-PHA monomer (58.1-68.8?mol%) in P.?putida LS46 cultured in glucose medium, 3-hydroxyoctanoate was the major monomer produced in octanoate medium (88?mol%).     

Oligonucleotide-stabilized fluorescent silver nanoclusters for turn-on detection of melamine

Fluorescence nanoclusters have been used for the determination of melamine for the first time. The method is based on the fluorescence turn-on of oligonucleotide-stabilized silver nanoclusters (DNA-Ag NCs) by melamine. The enhancement factors (I-I(0))/I(0) increase linearly with melamine concentrations over the range 5.0×10(-8)-7.0×10(-6) M (R(2)=0.998). The detection limit is 1.0×10(-8) M, which is approximately 2000 times lower than the US Food and Drug Administration estimated melamine safety limit of 20.0 μM. Furthermore, the milk samples spiked with melamine are analyzed with excellent recoveries.     

Benzimidazole bearing oxadiazole and triazolo-thiadiazoles nucleus: Design and synthesis as anticancer agents

Two new series of benzimidazole bearing oxadiazole[1-(1H-benzo[d]imidazol-2-yl)-3-(5-substituted-1,3,4-oxadiazol-2-yl)propan-1-ones (4a-l)] and triazolo-thiadiazoles[1-(1H-benzo[d]imidazol-2-yl)-3-(6-(substituted)-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazol-3-yl)propan-1-one (7a-e)] have been synthesized successfully from4-(1H-benzo[d]imidazol-2-yl)-4-oxobutanehydrazide (3) with an aim to produce promising anticancer agents. In vitro anticancer activities of synthesized compounds were screened at the National Cancer Institute (NCI), USA, according to their applied protocol against full NCI 60 human cell lines panel; results showed good to remarkable anticancer activity. Among them, compound (4j, NCS: 761980) exhibited significant growth inhibition and further screened at 10-fold dilutions of five different concentrations (0.01, 0.1, 1, 10 and 100μM) with GI(50) values ranging from 0.49 to 48.0μM and found superior for the non-small cell lung cancer cell lines like HOP-92 (GI(50) 0.49, TGI 19.9,LC(50) >100 and Log(10)GI(50) -6.30, Log(10)TGI -4.70, Log(10)LC(50) >-4.00).     

Synthesis, spectroscopy, and biological properties of vanadium(IV)-hydrazide complexes

The synthesis, spectroscopic, enzyme-inhibition, and free-radical-scavenging properties of a series of vanadium(IV) complexes, compounds 1-10, were investigated. These complexes exhibit a dimeric structure with hydrazide ligands coordinated in a bidentate fashion. All complexes are stable in the solid state, but exhibit varying degrees of stability in solution. In coordinating solvent such as DMSO, stepwise binding of two solvent molecules at the 6th positions trans to the V double bond O bond of the dimeric unit is observed. The dimeric compounds are converted to monomeric species in which both solvent molecules and the hydrazide ligands are coordinated to the V(IV) center. The free hydrazide ligands 11-20 were inactive against alpha-glucosidase, but the V(IV) complexes showed varying degrees of inhibition, depending on the type of ligand. The DPPH-radical-scavenging activities of 1-20 were determined, which indicated that steric and/or electronic effects responsible for changes in geometry play important roles in terms of antioxidant potential.     

Plant growth inhibitory activity of Ophiopogon japonicus Ker-Gawler and role of phenolic acids and their analogues: a comparative study

Allelopathic potential of Ophiopogon japonicus was investigated. The methanolic extract of O. japonicus roots strongly inhibited root and hypocotyls growth of lettuce. Sequential partitioning of the methanol extract with organic solvents showed that the diethyl ether and n-butanol extract possess strong plant growth inhibitory activities. The allelopathic constituents of the diethyl ether extract were isolated and identified as salicylic acid and p-hydroxybenzoic acid by NMR spectroscopy. Both of these phenolic acids were found in the aqueous extracts of leaves as well. The concentration of salicylic acid in roots and leaves were estimated as 0.011 and 0.02%, respectively, and it inhibited the root and shoot of tested plants by 50% even at less than 3 ppm. The p-hydroxybenzoic acid on the other hand was in less abundance (0.005%) and inhibited the plant growth to a lesser extent. The biological activity of commercially available O-methyl derivatives of these phenolic acids was also determined to establish structure–activity relationship. Among these, salicylic acid was found to be the most active one. These results suggest that Ophiopogon japonicus produces plant growth inhibitors, which are responsible for its potential allelopathic activity.     

D-Aspartate oxidase and D-amino acid oxidase are localised in the peroxisomes of terrestrial gastropods

D-Aspartate oxidase and D-amino acid oxidase were found in high activity in the tissues of representative species of terrestrial gastropods. Analytical subcellular fractionation demonstrated that both of these oxidases co-localised with the peroxisome markers, acyl-CoA oxidase and catalase, in the digestive gland homogenate. Electron microscopy of peak peroxisome fractions showed particles of uniform size with generally well preserved variably electron-dense matrices bounded by an apparently single limiting membrane. Many of the particles exhibited a core region of enhanced electron density. Catalase cytochemistry of peak fractions confirmed the peroxisome identity of the organelles. Peroxisome-enriched subcellular fractions were used to investigate the properties of gastropod D-aspartate oxidase and D-amino acid oxidase activities. The substrate and inhibitor specificities of the two activities demonstrated that two distinct enzymes were present analogous to, but not identical to, the equivalent mammalian peroxisomal enzymes.     

Microsatellite Marker Linked to a Leaf Rust Resistance Gene from Triticum monococcum L Transferred to Bread Wheat

Triticum monococcum L, a diploid wheat species closely related to the A genome of cultivated wheats, is highly resistant to leaf rust. A synthetic amphiploid, T. monococcum — T. durum was crossed with T. aestivum cv WL711, highly susceptible to leaf rust. Leaf rust resistant derivatives were selected among backcross generations with the recurrent parent WL711 and cytologically analysed. Chromosome number of the leaf rust resistant BC₁F₃ progenies varied from 39 to 44. Six leaf rust resistant and susceptible bulks from different BC₁F₃ progenies were analysed using 29 wheat microsatellite(WMS) markers already mapped on A genome of bread wheat and found polymorphic among parents. One T. monococcum specific allele of WMS gwm136 locus was found to be closely linked to the leaf rust resistance gene in all the resistant bulks. Differential chromosome number, frequency of univalents and multivalents, however, indicated that the critical T. monococcum chromosome might be present in addition to the A genome chromosomes of wheat, substituted either for the B or D genome chromosome of wheat or translocated to chromosome 1A of wheat in one or the other bulks. The association of the T. monococcum specific allele of WMS gwm136 locus to leaf rust resistance was further confirmed from bulked segregant analysis in BC₂F₁ generation.     

Pro-oxidant, anti-oxidant and cleavage activities on DNA of curcumin and its derivatives demethoxycurcumin and bisdemethoxycurcumin.

Curcumin, a naturally occurring phytochemical responsible for the colour of turmeric shows a wide range of pharmacological properties including antioxidant, anti-inflammatory and anti-cancer effects. We have earlier shown that curcumin in the presence of Cu(II) causes strand cleavage in DNA through generation of reactive oxygen species, particularly the hydroxyl radical. Thus, curcumin shows both antioxidant as well as pro-oxidant effects. In order to understand the chemical basis of various biological properties of curcumin, we have studied the structure-activity relationship between curcumin and its two naturally occurring derivatives namely demethoxycurcumin (dmC) and bisdemethoxycurcumin (bdmC). Curcumin was found to be the most effective in the DNA cleavage reaction and a reducer of Cu(II) followed by dmC and bdmC. The rate of formation of hydroxyl radicals by the three curcuminoids also showed a similar pattern. The relative antioxidant activity was examined by studying the effect of these curcuminoids on cleavage of plasmid DNA by Fe(II)-EDTA system (hydroxyl radicals) and the generation of singlet oxygen by riboflavin. The results indicate that curcumin is considerably more active both as an antioxidant as well as an oxidative DNA cleaving agent. The DNA cleavage activity is the consequence of binding of Cu(II) to various sites on the curcumin molecule. Based on the present results, we propose three binding sites for Cu(II). Two of the sites are provided by the phenolic and methoxy groups on the two benzene rings and the third site is due to the presence of 1,3-diketone system between the rings. Furthermore, both the antioxidant as well as pro-oxidant effects of curcuminoids are determined by the same structural moieties.     

Fibre Optic SPR Sensor Using Functionalized CNTs for the Detection of SMX: Comparison with Enzymatic Approach

Plasmonics - A novel approach for the detection of sulfamethaxazole (SMX) based on fibre optic surface plasmon resonance (SPR) technique and functionalized carbon nanotubes (CNTs) is proposed for 0...