Designing and Judd–Ofelt evaluation of versatile luminescent Eu (III) complexes sensitized with β-diketone ligand for multifarious applications

The present research work entails the synthesis of one binary and four ternary red light−emitting Eu (III)-based complexes with 3-benzylidene-2,4-pentanedione as the main ligand and 1,10-phenanthroline, bathophenanthroline, neocuproine, and 4,4′-′dimethyl-2,2′-′bipyridyl as auxiliary ligands. The metal–organic framework of the series was elucidated using energy dispersive X-ray analysis, elemental analysis, Fourier transform infrared spectroscopy, and proton nuclear magnetic resonance. This Eu (III) series exhibits optimum thermal stability, making them a promising candidate for organic light-emitting diodes. On the basis of emission spectra, their optical parameters such as nonradiative and radiative decay rates, luminescence decay time, intrinsic quantum efficiency, and Judd–Ofelt intensity parameter were determined. The monocentric luminescence and Judd–Ofelt parameters reveal the absence of symmetry around the europium center. CIE chromaticity coordinates, correlated color temperature values, color purity, and asymmetric ratios authenticate the color coordinates of the complexes in red region. Optical band gap values lie within the range of wide band gap semiconductors, indicating their utilization in military radars and biological labeling.     

Conformational Preferences of Hypermodified Nucleoside Lysidine (k2C) Occurring at “Wobble” Position in Anticodon Loop of tRNAIle

Conformational preferences of hypermodified nucleoside, 4-amino-2-(N⁶-lysino)-1-(β-D-ribofuranosyl) pyrimidinium (Lysidine or 2-lysyl cytidine), usually designated as k²C, have been investigated theoretically by the quantum chemical perturbative configuration interaction with localized orbitals (PCILO) method. The zwitterionic, non-zwitterionic, neutral, and tautomeric forms have been studied. Automated geometry optimization using molecular mechanics force field (MMFF), semi-empirical quantum chemical PM3, and ab initio molecular orbital Hartree-Fock SCF quantum mechanical calculations have also been made to compare the salient features. The predicted most stable conformations of zwitterionic, non-zwitterionic, neutral, and tautomeric form are such that in each of these molecules the orientation of lysidine moiety (R) is trans to the N(1) of cytidine. The preferred base orientation is anti (χ = 3°) and the lysine substituent folds back toward the ribose ring. This results in hydrogen bonding between the carboxyl oxygen O(12a) of lysine moiety and the 2′-hydroxyl group of ribose sugar. In all these four forms of lysidine O(12a)…H-C(9) and O(12b)…H-N(11) interactions provide stability to respective stable conformers. Watson-Crick base pairing of lysidine with A is feasible only with the tautomeric form of usual anti oriented lysidine. This can help in recognition of AUA codon besides in avoiding misrecognition of AUG.     

Ribosomal activity of the 16 S.23 S RNA complex

It has been demonstrated in this laboratory that 16 S and 23 S RNAs form a binary complex like 30 S and 50 S ribosomes under certain specific conditions, and 5 S RNA can be incorporated into the complex in stoichiometric amounts in presence of three ribosomal proteins, L5, L18, and L15/25. These studies raised the basic question of whether such complex will have biological activity. Therefore, the following steps in protein synthesis were examined with the complex in place of the ribosomes: (i) poly-U-dependent binding of phenylalanyl tRNA; (ii) EF-G-dependent GTPase activity; (iii) initiation complex formation; (iv) peptidyl transferase activity; and (v) poly-U-dependent polyphenylalanine synthesis. All the steps could be unequivocally demonstrated by the addition of a limited number of proteins although the complex had comparatively much less activity than 70 S ribosomes. It appears that rRNAs are directly involved in various steps of protein synthesis. Furthermore, the 16 S.23 S RNA complex might have acted as a primitive ribosome, as suggested by Crick and Orgel.     

Root colonization of different hosts by the vesicular-arbuscular mycorrhizal fungus Glomus dimorphicum

Colonization of the roots of beans, alfalfa, onions, red clover, corn, and four barley cultivars (Bonanza, Klondike, Gateway 63, and Olli) by Glomus dimorphicum Boyetchko and Tewari, a vesicular-arbuscular mycorrhizal fungus isolated from a barley field in Alberta, Canada, was studied under greenhouse conditions. Infection levels were low in all four barley cultivars but were higher in beans, alfalfa, and onions and were highest in red clover and corn roots. The infection patterns of G. dimorphicum varied among all the hosts. Coiling of intracellular hyphae occurred in corn, alfalfa, and red clover roots. Appreciable numbers of intraradical vesicles were found only in red clover and bean roots, while arbuscules formed in all hosts except barley. It was concluded that the pattern of root colonization by G. dimorphicum is influenced by the host genome and that the fungal morphology in the roots is variable and, thus, not diagnostic for the mycorrhizal species.     

Mendelian transmission,structure and expression of transgenes following their injection into the cytoplasm of trout eggs

High frequencies of mosaic transgenic trout are generated when linear DNA fragments are injected into the egg cytoplasm. The fact that these animals transmit the foreign DNA to a minority of their offspring suggests that their germline is also mosaic, but it may also indicate that some transgenes are lost. We have produced seven F₂ families from wild-type females mated with F₁ transgenic males. In all of them, the ratio of transgenics was Mendelian, and classical Southern analyses clearly showed the segregation of one or two foreign loci. They also provide firm arguments for gene integration in families carrying single-copy transgenes. Images obtained by Southern blotting strongly suggest the presence of extrachromosomal linear concatemers in two other families. However, this hypothesis was contradicted by further analyses usingin situ hybridization on chromosomes and with pulse field gel electrophoresis (PFGE). The reconciliation of these apparently contradictory observations is allowed by a model in which integrated concatemers adopt hairpin loop structures at the junction of inversely oriented copies. Further experiments with denaturing electrophoresis, which opens such secondary structures, provides additional support for this model. In this stable gene transfer system accompanied by chromosomal integration, the CAT reporter gene was expressed from the promoter/enhancer of human cytomegalovirus early genes, in all tissues examined in F₀ fishes, as well as in the F₁ offsprings of nine males. This indicates that the palindromic structures of some of the transgenes do not prevent their expression.     

Epiphytic succession on tree trunks in a mixed oak-cedar forest,Kumaun Himalaya

The epiphytes present at about breast height on trunks of different size were studied for three major tree species in a seasonally wet forest at 2050 m altitude in the Kumaun Himalaya: Cedrus deodora, Quercus floribunda and Q. leucotrichophora. The total biomass and species number per unit trunk area, were found to increase with trunk size. It was supposed that the results indicated a succession in the type of epiphytic cover from young trunks to older trunks.The amount of loose material (plant remains and soil) per unit area of trunk increased with increasing girth. The C:N ratio in this material was initially very high on the oaks (129–197) and declined with increasing trunk size (to 73–78); the ratio was constant across girth classes in the cedar (86–87).Bryophytes produced most biomass on most trunks; next to them were lichens on the smallest trunks, and flowering plants on the largest. The number of species of epiphytes was similar on all three host species. The results are discussed in relation to contemporary ideas on diversity and strategies.Nomenclature follows: Ganguli (1972, 1977 & 1980); Kashyap (1929); Nayar (1970); Osmaston (1927).Financial support from the Council of Scientific and Industrial Research, Delhi and University Grants Commission, New Delhi is gratefully acknowledged.     

Lithium Treatment Aggregates the Adverse Effects on Erythrocytes Subjected to Arsenic Exposure

The present study was designed to investigate the effects of lithium treatment on red blood cells which were given arsenic exposure. Long-term lithium therapy is being extensively used for the treatment of bipolar disorders. Arsenic is a group I carcinogen and a major toxic pollutant in drinking water that affects millions of people worldwide. Male SD rats were segregated into four groups, viz. normal control, lithium treated, arsenic treated, and lithium + arsenic treated. Lithium was supplemented as lithium carbonate at a dose level of 1.1 g/kg diet for a period of 8 weeks. Arsenic was given in the form of sodium arsenite at a dose level of 100 ppm in drinking water, ad libitum, for the same period. Lysates of red blood cells were used to investigate the effects of lithium and arsenic treatments on anti-oxidant enzymes, reduced glutathione (GSH), and lipid peroxidation (LPO) levels. Various hematological parameters, activities of Na⁺ K⁺ ATPase and delta-aminolevulinic acid dehydratase (δ-ALAD) were also assessed. A significant reduction was observed in the activities of antioxidant enzymes, GSH levels, total erythrocyte counts, Na⁺ K⁺ ATPase, and ALAD enzyme activities in lysates of red blood cells when exposed either to lithium or arsenic. In addition, a significant increase in the levels of malondialdehyde (MDA), lymphocytes, neutrophils, and total leukocytes was also observed following lithium as well as arsenic treatments. However, when arsenic-treated rats were subjected to lithium treatment, a pronounced alteration was noticed in all the above parameters. Therefore, we conclude that lithium supplementation to the arsenic-treated rats enhances the adverse effects on red blood cells and therefore use of lithium may not be medicated to patients who are vulnerable to arsenic exposure through drinking water. It can also be inferred that adverse effects of lithium therapy may get aggravated in patients thriving in the arsenic-contaminated area.

     

Effective management of soft rot of ginger caused by Pythium spp. and Fusarium spp.: emerging role of nanotechnology

Applied Microbiology and Biotechnology - Ginger (Zingiber officinale Rosc.) is a tropical plant cultivated all over the world due to its culinary and medicinal properties. It is one of the most...     

Histochemical studies on the distribution of β-glucuronidase and succinic dehydrogenase in young and old spinal ganglion cells of the rat

Summary The present study compares the distribution of -glucuronidase and succinic dehydrogenase in young and old spinal ganglion cells of rat. In young cells there are indications of cyclic activity of these enzymes, i.e., in some stages there are perinuclear concentrations of the enzymes, at other times -glucuronidase and succinic dehydrogenase are uniformly distributed throughout the cytoplasm. These stages have been discussed with the identical distribution of mitochondria. However, in old spinal ganglion cells both -glucuronidase and succinic dehydrogenase become mainly concentrated in the pigment areas, suggesting thereby their possible role in the production of pigment, through the medium of the mitochondria.