No abstract

A new probe 2-benzo[1,2,5]thiadiazol-4-yl-isoindole-1,3-dione (BTI) based on the Gabriel reaction was developed for hydrazine which shows promising selectivity towards hydrazine over other analytes.

Bradyrhizobial invasion in dalbergoid legumes like Arachis hypogaea and endophytic bacterial invasions in non-legumes like Oryza sativa occur through epidermal cracks. Here, we show that there is no overlap between the bradyrhizobial consortia that endosymbiotically and endophytically colonise these plants. To minimise contrast due to phylogeographic isolation, strains were collected from Arachis/Oryza intercropped fields and a total of 17 bradyrhizobia from Arachis (WBAH) and 13 from Oryza (WBOS) were investigated. 16SrRNA and concatenated dnaK-glnII-recA phylogeny clustered the nodABC-positive WBAH and nodABC-deficient WBOS strains in two distinct clades. The in-field segregation is reproducible under controlled conditions which limits the factors that influence their competitive exclusion. While WBAH renodulated Arachis successfully, WBOS nodulated in an inefficient manner. Thus, Arachis, like other Aeschynomene legumes support nod-independent symbiosis that was ineffectual in natural fields. In Oryza, WBOS recolonised endophytically and promoted its growth. WBAH however caused severe chlorosis that was completely overcome when coinfected with WBOS. This explains the exclusive recovery of WBOS in Oryza in natural fields and suggests Nod-factors to have a role in counterselection of WBAH. Finally, canonical soxY1 and thiosulphate oxidation could only be detected in WBOS indicating loss of metabolic traits in WBAH with adaptation of symbiotic lifestyle.

A pyrene containing chemosensor viz. has been designed for the efficient and selective detection of Cu(2+) and F(-) ions in dual sensing mode which do not interfere with each other. The chemosensing behavior of towards Cu(2+) was demonstrated through fluorescence, time resolved fluorescence spectroscopy, and visual fluorescence colour changes, and towards F(-) through naked-eye colour changes, absorption and (1)H NMR titrations. The chemosensor shows excellent selectivity towards Cu(2+) through an excimer switch-off mechanism. Density Functional Theory (DFT) calculations were performed to show the structure and electronic properties of and its copper complex [-Cu(2+)]. The selectivity and sensitivity towards F(-) were explained in terms of H-bonding interactions between and F(-), then deprotonation of . The biological application of has been evaluated in HEK 293 cells and it exhibits good membrane permeability for the detection of Cu(2+). The sensor also shows appreciable sensitivity towards fluoride in toothpaste.

A BODIPY-based pyrenebutyrate-linked (BPB) chromogenic and fluorogenic probe was synthesized and characterized for the specific detection of hydrazine.

A new ‘turn-ON’ fluorescent probe, pyrene appended thymine acetamide (PTA), with high sensitivity and selectivity for the detection of uric acid (UA) was developed and first time imaging of uric acid in living cells in water was achieved.

No abstract

A new coumarin-appended thioimidazole-linked imine conjugate, viz. has been synthesized and characterized. has been found to recognize Cu(2+) selectively among a wide range of biologically relevant metal ions. The chemosensing behavior of has been demonstrated through fluorescence, absorption, visual fluorescence color changes, ESI-MS and (1)H NMR titrations. The chemosensor showed selectivity toward Cu(2+) by switch on fluorescence among the 18 metal ions studied with a detection limit of 1.53 μM. The complex formed between and Cu(2+) is found to be 1 : 1 on the basis of absorption and fluorescence titrations and was confirmed by ESI-MS. DFT and TDDFT calculations were performed in order to demonstrate the structure of and [CuL] and the electronic properties of chemosensor and its copper complex. This highly fluorescent [CuL] complex has been used to recognize sulphide selectively among the other allied anions. Microstructural features of and its Cu(2+) complex have been investigated by SEM imaging (scanning electron microscopy). The biological applications of were evaluated in Vero cells and it was found to exhibit low cytotoxicity and good membrane permeability for the detection of Cu(2+).