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Cholera, an acute infection of the small intestine, is caused by Vibrio cholerae. The present study identified a hypothetical protein in V. cholerae O395, which was predicted to be acquired through horizontal gene transfer the origin of which was found to be from a phage. Its expression was further confirmed by RT-PCR. Homology based 3D model of the hypothetical protein indicated DksA like homologue. Protein binding site of 3D-model revealed a deep cleft which may influence the dimer formation and interaction with ds-DNA molecule. Also, canonical function of direct interaction with RNA polymerase (RNAP) holoenzyme in complex with ppGpp suggests its dual role in the pathogenesis of cholera. [ABSTRACT FROM AUTHOR]

ContextThe effect of 6-gingerol (6G), the bioactive component ofZingiber officinaleRoscoe (Zingiberaceae), in the reduction ofVibriocholerae(Vibrionaceae)-induced inflammation has not yet been reported. Materials and methodsCell viability assay was performed to determine the working concentration of 6G. Elisa and RT-PCR were performed with Int 407 cells treated with 50 μM 6G and 100 multiplicity of infection (MOI)V.choleraefor 0, 2, 3, 3.5, 6 and 8 h to determine the concentration of IL-8, IL-6, IL-1α and IL-1β in both protein and RNA levels. Furthermore, the effect of 50 μM 6G on upstream MAP-kinases and NF-κB signalling pathways was evaluated at 0, 10, 15, 30, 60 and 90 min. ResultsThe effective dose (ED50) value of 6G was found to be 50 μM as determined by cell viability assay. Pre-treatment with 50 μM 6G reducedV.choleraeinfection-triggered levels of IL-8, IL-6, IL-1α and IL-1β by 3.2-fold in the protein level and two-fold in the RNA level at 3.5 h. The levels of MAP-kinases signalling molecules like p38 and ERK1/2 were also reduced by two- and three-fold, respectively, after 30 min of treatment. Additionally, there was an increase in phosphorylated IκBα and down-regulation of p65 resulting in down-regulation of NF-κB pathway. ConclusionOur results showed that 6G could modulate the anti-inflammatory responses triggered byV.cholerae-induced infection in intestinal epithelial cells by modulating NF-κB pathway. [ABSTRACT FROM PUBLISHER]

Heat shock protein-47 (Hsp-47) is exclusive collagen specific molecular chaperone involved in the maturation, processing and secretion of procollagen. Hsp-47 is consistently upregulated in several fibrotic diseases. Till date there is no potential antifibrotic small molecule drug available and Hsp-47 is known to be potential therapeutic target for fibrotic disorder and drug designing. We used the de novo drug design approach followed by pharmacophore generation and virtual screening to propose Hsp-47 based antifibrotic molecules. We used e-LEAD server for de novo drug design and ZINCPharmer for 3D pharmacophore generation and virtual screening. The virtually screened molecule may inhibit direct recruitment of collagen triple helix to interact with Hsp-47 and act as antifibrotic drug. [ABSTRACT FROM AUTHOR]

Early detection and quantification of DNA damage in oral premalignancy or malignancy may help in management of the disease and improve survival rates. The comet assay has been successfully utilised to detect DNA damage in oral premalignant or malignancy. However, due to the invasive nature of collecting blood, it may be painful for many unwilling patients. This study compares the micronucleus (MN) assay in oral buccal mucosa cells with the comet assay in peripheral blood cells in a subset of oral habit-induced precancer and cancer patients. For this, MN assay of exfoliated epithelial cells was compared with comet assay of peripheral blood leucocytes among 260 participants, including those with oral lichen planus (OLP; n = 52), leukoplakia (LPK; n = 51), oral submucous fibrosis (OSF; n = 51), oral squamous cell carcinoma (OSCC; n = 54) and normal volunteers (n = 52). Among the precancer groups, LPK patients showed significantly higher levels of DNA damage as reflected by both comet tail length (P < 0.0001) and micronuclei (MNi) frequency (P = 0.0009). The DNA damage pattern in precancer and cancer patients was OLP < OSF < LPK < OSCC, and with respective oral habits, it was multiple habits > cigarette + khaini > cigarette smokers > areca + khaini > areca. There was no significant difference in the comet length and MNi frequency between males and females who had oral chewing habits. An overall significant correlation was observed between MNi frequency and comet tail length with r = 0.844 and P < 0.0001. Thus, the extent of DNA damage evaluation by the comet assay in peripheral blood cells is perfectly reflected by the MN assay on oral exfoliated epithelial cells, and MNi frequency can be used with the same effectiveness and greater efficiency in early detection of oral premalignant conditions. [ABSTRACT FROM AUTHOR]

Vibrio cholerae, the causative agent of epidemic cholera, has been a constant source of concern for decades. It has constantly evolved itself in order to survive the changing environment. Acquisition of new genetic elements through genomic islands has played a major role in its evolutionary process. In this present study a hypothetical protein was identified which was present in one of the predicted genomic island regions of the large chromosome of V. cholerae O395 showing a strong homology with a conserved phage encoded protein. In-silico physicochemical analysis revealed that the hypothetical protein was a periplasmic protein. Homology modeling study indicated that the hypothetical protein was an unconventional and atypical serine protease belonging to HtrA protein family. The predicted 3D-model of the hypothetical protein revealed a catalytic centre serine utilizing a single catalytic residue for proteolysis. The predicted catalytic triad may help to deduce the active site for the recruitment of the substrate for proteolysis. The active site arrangements of this predicted serine protease homologue with atypical catalytic triad is expected to allow these proteases to work in different environments of the host. [ABSTRACT FROM AUTHOR]

Here, we report the design and synthesis of a Schiff base probe, DBNHC ((E)-2-(2,4-dihydroxybenzylidene)-N-(naphthalen-1-yl)hydrazine-1-carbothioamide), and its interaction with bovine serum albumin (BSA). In ∼100% PBS buffer, the probe DBNHC can self-assemble into nonfluorescent nanoaggregates due to the aggregation caused quenching (ACQ) effect. However, it becomes highly fluorescent (∼14 fold) in the presence of BSA which facilitates the disassembly of nanoaggregates into its monomer. The site-selective fluorescence displacement assay and molecular docking simulations reveal that mainly hydrogen bonding, π⋯sulphur and π⋯alkyl interactions are responsible for the disassembly of nanoaggregates leading to encapsulation of DBNHC monomer at site II in BSA, resulting in a cyan green emission. The detection limit determined by the 3σ/slope method was found to be 58 nM, and the lower dissociation constant [Kd = (1.506 ± 0.196) μM] value suggests strong binding between the probe and BSA. Further, DBNHC was used for cell incubation and in vitro fluorescence imaging of BSA. [ABSTRACT FROM AUTHOR]

A new rhodamine 6G-benzylamine-based sensor (L1), having only hydrocarbon skeletons in the extended part, was synthesized and characterized by single-crystal X-ray crystallographic study. It exhibited excellent selective and sensitive recognition of trivalent metal ions M3+ (M = Fe, Al and Cr) over mono- and di-valent and other trivalent metal ions. A large enhancement of the fluorescence intensity for Fe3+ (41-fold), Al3+ (31-fold) and Cr3+ (26-fold) was observed upon the addition of 3.0 equivalent of these metal ions into the probe in H2O/CH3CN (4 : 1, v/v, pH 7.2) with naked eye detection. The corresponding Kf values were evaluated to be 9.4 × 103 M−1 (Fe3+), 1.34 × 104 M−1 (Al3+) and 8.7 × 103 M−1 (Cr3+). Quantum yields of the L1, [L1–Fe3+], [L1–Al3+] and [L1–Cr3+] complexes in H2O/CH3CN (4 : 1, v/v, pH 7.2) were found to be 0.012, 0.489, 0.376 and 0.310, respectively, using rhodamine-6G as standard. LODs for Fe3+, Al3+ and Cr3+ were determined by 3σ methods and found to be 1.28, 1.34 and 2.28 μM, respectively. Cyanide ion scavenged Fe3+ from the [Fe3+–L1] complex and quenched its fluorescence via its ring-closed spirolactam form. Advanced level molecular logic devices using different inputs (2 and 4 inputs) as advanced level logic gates and memory devices were constructed. The large enhancement in fluorescence emission of L1 upon complexation with M3+ metal ions makes the probe suitable for the bio-imaging of M3+ (M = Fe, Al and Cr) in living cells. [ABSTRACT FROM AUTHOR]

Methodological synthesis of a new biocompatible bi-compartmental rhodamine based probe (L 3 ) provides a multi-inputs and multi-outputs molecular logic circuit based on simple chemosensing phenomena. Spectroscopic responses of Cu 2+ and Hg 2+ towards L 3 together with reversible binding of S 2- with L 3 -Cu 2+ and L 3 -Hg 2+ complexes help us to construct a thee-input molecular circuit on their control and sequential addition to a solution of L 3 in a mixed organo-aqueous medium. We have further successfully encoded binary digits out of these inputs and outputs which may convert a three-digit input string into a two-digit output string resulting a simple monomolecular logic circuit. Such a molecular ‘Boolean’ logic operation may improve the complexity of logic gate circuitry and computational speed and may be useful to employ in potential biocompatible molecular logic platforms. [ABSTRACT FROM AUTHOR]

Neo-tanshinlactone (NTL) a natural product is known for its specificity and selectivity towards the breast cancer cells. By NTL D-ring modification approach, 13 new analogues were synthesized ( 1A – 1M ). Among them 1J showed the best anticancer activity in MCF-7 (ER+, PR+/−, HER2−), SKBR3 (ER−, PR−, HER2+) and MDA-MB-231 (ER−, PR−, HER2−) cells lines with IC 50 value 11.98 nM, 23.71 nM, and 62.91 nM respectively. 1J showed minor grove binding interaction with DNA at AT-rich region and induced DNA double strand breaks (DDSBs). This had triggered several key molecular events involving, activation of ATM, Chk2 and p53, reduction in mitochondrial potential (Δ ψ m ) leading to caspase-3 and PARP cleavage mediated apoptosis. These results along with other biochemical studies strongly suggest that novel NTL analogue 1J caused DNA cleavage mediated apoptosis in the breast cancer cells and this may serve as potential lead for future breast cancer treatment. [ABSTRACT FROM AUTHOR]

A new type of easily synthesized rhodamine-based chemosensor L3, with potential NO2 donor atoms, selectively and rapidly recognizes Hg2+ ions in the presence of all biologically relevant metal ions and toxic heavy metals. A very low detection limit (78 nM) along with cytoplasmic cell imaging applications with no or negligible cytotoxicity indicate good potential for in vitro/in vivo cell imaging studies. SEM and TEM studies reveal strongly agglomerated aggregations in the presence of 5 mM SDS which turn into isolated core shell microstructures in the presence of 9 mM SDS. The presence of SDS causes an enhanced quantum yield (φ) and stability constant (Kf) compared to those in the absence of SDS. Again, the FI of the [L3–Hg]2+ complex in an aqueous SDS (9 mM) medium is unprecedentedly enhanced (∼143 fold) compared to that in the absence of SDS. All of these observations clearly manifest in the enhanced rigidity of the [L3–Hg]2+ species in the micro-heterogeneous environment significantly restricting its dynamic movements. This phenomenon may be ascribed as an aggregation induced emission enhancement (AIEE). The fluorescence anisotropy assumes a maximum at 5 mM SDS due to strong trapping (sandwiching) of the doubly positively charged [L3–Hg]2+ complex between two co-facial laminar microstructures of SDS under pre-miceller conditions where there is a strong electrostatic interaction that causes an improved inhibition to dynamic movement of the probe-mercury complex. On increasing the SDS concentration there is a phase transition in the SDS microstructures and micellization starts to prevail at SDS ≥ 7.0 mM. The doubly positively charged [L3–Hg]2+ complex is trapped inside the hydrophobic inner core of the micelle which is apparent from the failure to quench the fluorescence of the complex on adding 10 equivalents of H2EDTA2− solution but in the absence of SDS it is quenched effectively. [ABSTRACT FROM AUTHOR]

A 2-hydroxy-5-methyl-benzene-1,3-dicarboxaldehyde di-oxime based turn-on blue emission fluorescent probe was found to recognize both AsO2− and H2AsO4− in a purely aqueous medium in intra and extra-cellular conditions. Self-organization of the ligand in the absence and presence of AsO2− and H2AsO4− was investigated by DLS, optical microscopy, optical fluorescence microscopy and FE-SEM methods. [ABSTRACT FROM AUTHOR]

A diformyl-p-cresol (DFC)-8-aminoquinoline based dual signaling probe was found to exhibit colorimetric and fluorogenic properties on selective binding towards Mg2+ and Zn2+. Turn-on fluorescent enhancements (FE) as high as 40 fold and 53 fold in 9 : 1 MeCN/water (v/v) at pH 7.2 in HEPES buffer for Mg2+ and Zn2+, respectively, were observed. The binding constants determined from the fluorescence titration data are: K = (1.52 ± 0.21) × 105 M−1 and (9.34 ± 4.0) × 103 M−2 at n = 1 and 0.5, for Mg2+ and Zn2+, respectively. The L : M binding ratios were also determined by Job's method, which support the above findings. This is further substantiated by HRMS analysis. Due to solubility in mixed organo-aqueous solvents as well as cell permeability it could be used for the in vitro/in vivo cell imaging of Mg2+ and Zn2+ ions with no or negligible cytotoxicity. This probe could be made selective towards Mg2+ over Zn2+ in the presence of TPEN, both under intra- and extracellular conditions and is superior to other Mg2+ probes which suffer from selectivity of Mg2+ over Ca2+ or Zn2+. Furthermore the dissociation constant (Kd = 6.60 μM) of the Mg2+-(DFC-8-AQ) complex is far lower than the so far reported Mg2+ probes which fall in the mM range. [ABSTRACT FROM AUTHOR]

[Display omitted] • We have successfully designed and synthesized a new biocompatible chromo- and fluorogenic probe L2 derived from rhodamine-6G which showed a selective and sensitive colorimetric as well as " turn-ON " fluorescence response towards Fe3+ ion over mono-, di- and other trivalent metal ions. • Complete aqua friendliness of this probe has drawn special attention over other rhodamine 6G based chemosensors. • A large enhancement of fluorescence intensity of L2 (14 fold) in the presence of Fe3+ in aqueous medium (HEPES buffer at pH 7.2) with the development of reddish yellow color clearly indicates that this probe L2 can be used for the detection of Fe3+ through naked eye. • The K f value was evaluated to be (1.16 ± 0.04) x 104 M−1 from the fluorescence titration data at systematic increasing concentration of metal ions and fixed 20 μM concentration of ligand. • The higher values of quantum yields (0.523) for [ L2 -Fe3+] over the free ligand (0.013) indicate the higher stability of the complexes in the excited states. • Job's plot confirms 1:1 stoichiometric ratio for the binding of Fe3+ with L2. • An excellent reversible fluorescence ' OFF-ON " property of L2 has been observed through fluorescence study with the sequential addition of Fe3+ and CN– ions at room temperature which suggests the reusability of this chemosensor. • The detection limit of L2 for Fe3+ was evaluated to be 4.184 μM and this makes the probe usable to quantify the Fe3+ in real water samples. • As the sensing phenomenon is reversible it helps to frame INHIBIT gate and memory devices. A novel rhodamine-6G based biocompatible chromo- and fluorogenic "OFF-ON" sensor L2 , having amide based metal ion receptor, has been synthesized using Michael addition reaction and characterized by IR, NMR and HRMS spectroscopic studies. It exhibits an excellent selectivity and sensitivity towards Fe3+ in aqueous medium over mono- and di-valent and other trivalent metal ions. A 14-fold enhancement of fluorescence intensity was found upon addition of 11.5 equivalent Fe3+ ion into the probe L2 in H 2 O (pH 7.2, 10 mM HEPES buffer) with colour change from colourless to reddish yellow, providing an opportunity for naked eye detection of Fe3+. The corresponding binding constant K f was evaluated to be (1.16 ± 0.04) x 104 M−1 with 1:1 stoichiometry. Quantum yields of L2 and [L2 - Fe3+] complex in H 2 O (pH 7.2, 10 mM HEPES buffer) were found to be 0.013 and 0.523, respectively using Rhodamine-6G as standard. LOD of L2 for Fe3+ detection in aqueous medium determined by 3σ/slope method was found to be 4.184 μM. Cyanide ion scavanges Fe3+ from [L2 - Fe3+] resulting quenching of fluorescence due to re-attainment of the non-fluorescent spirolactam ring form of the probe. As the sensing phenomenon is reversible, it helps to frame INHIBIT logic gate and memory devices. [ABSTRACT FROM AUTHOR]

The aging-associated increase of cancer risk is linked with stromal fibroblast senescence and concomitant cancer-associated fibroblast (CAF) activation. Surprisingly little is known about the role of androgen receptor (AR) signaling in this context. We have found downmodulated AR expression in dermal fibroblasts underlying premalignant skin cancer lesions (actinic keratoses and dysplastic nevi) as well as in CAFs from the 3 major skin cancer types, squamous cell carcinomas (SCCs), basal cell carcinomas, and melanomas. Functionally, decreased AR expression in primary human dermal fibroblasts (HDFs) from multiple individuals induced early steps of CAF activation, and in an orthotopic skin cancer model, AR loss in HDFs enhanced tumorigenicity of SCC and melanoma cells. Forming a complex, AR converged with CSL/RBP-Jκ in transcriptional repression of key CAF effector genes. AR and CSL were positive determinants of each other's expression, with BET inhibitors, which counteract the effects of decreased CSL, restoring AR expression and activity in CAFs. Increased AR expression in these cells overcame the consequences of CSL loss and was by itself sufficient to block the growth and tumor-enhancing effects of CAFs on neighboring cancer cells. As such, the findings establish AR as a target for stroma-focused cancer chemoprevention and treatment. [ABSTRACT FROM AUTHOR]

A new, highly sensitive probe L2 for the selective detection of Hg2+ in organo-aqueous (H2O:CH3CN, 1:1, v/v, HEPES buffer, pH 7.2) medium has been synthesized from rhodamine 6G-hydrazide and 4-nitroindole-3-carboxaldehyde. It was thoroughly characterized by physicochemical techniques including single crystal X-ray diffraction studies. The reaction of L2 with Hg2+ gives a 1:1 stoichiometry resulting in a 146 fold fluorescence enhancement and a binding constant (Kf) of 3 × 104 M−1. The spirolactam form of the probe is non-fluorescent; however, it shows dual channel (absorbance and fluorescence) recognition of Hg2+ via CHEF effect through the opening of the spirolactam ring. The quantum yields of L2 (0.00045) and L2-Hg2+ (0.29) show the higher stability of complex in the excited state over the free ligand. The 44.5 nM LOD value demonstrates the detection of Hg2+ at a very low concentration range. Cell imaging studies show the cytoplasmic recognition of Hg2+ by L2. Experimental results are comparable with theoretical values obtained by DFT studies. The fluorescence emission of the complex was completely quenched by I- and from the reversibility studies an advance level INHIBIT logic gate and memory device can be framed. [ABSTRACT FROM AUTHOR]

A novel hexa-coordinating rhodamine-based chemosensor, HL6, with N4O2 donor atoms, selectively and rapidly recognizes Fe3+ in the presence of all biologically relevant as well as toxic metal ions, numerous anions (except for F− and I−, which quench FI) and amino acids. The lower detection limit (110 nM) along with cytoplasmic cell imaging applications with negligible cytotoxicity provides a good opportunity towards in vitro/in vivo cell imaging of Fe3+ ions. Scanning electron microscopy (SEM) studies reveal a spherical microstructure for the free ligand, HL6, which melts upon increasing the applied voltage (≥2 kV); however, this is reduced in size in the presence of SDS, morphology remaining the same. [L6-Fe]2+ gives hexagonal rod-like microstructures due to π…π stacking extended in a one dimensional fashion, which, in the presence of SDS, turn into cubic microstructures. However, in the presence of HSA both HL6 and [L6-Fe]2+ agglomerated severely. A plot of FI (or r) vs. [SDS] at constant [L6-Fe2+] (20 μM) shows a rapid decrease in FI (or r); FI or r reaches a minimum at ∼2 mM SDS and then increases and becomes saturated at ≥8 mM SDS. The initial rapid decrease in FI or r with the increase in [SDS] arises due to the breakdown of the self-assembled microstructures of [L6-Fe]2+ formed probably through π…π stacking in pure aqueous solution in the presence of SDS (≤2 mM). The increase in FI or r with [SDS] beyond 2 mM may arise due to trapping of the [L6-Fe]2+ moiety inside the micellar cavity thereby giving it a thermodynamically rigid structure. Again, fluorescence anisotropy measured as a function of HSA concentration (0–70 μM) at a fixed concentration of HL6 and Fe3+ (20 μM each) at 555 nm showed a gradual increase in r with the increase in [HSA]. Site selective binding and molecular modeling studies revealed that [L6-Fe]2+ predominantly binds in the subdomain IIA of HSA by both hydrophobic and electrostatic forces. A circular dichroism (CD) study clearly points towards the reduction in α-helical organization of the protein and subsequent increase in the coiled structure upon binding with [L6-Fe]2+ indicating a small but definitive partial unfolding of the protein. [ABSTRACT FROM AUTHOR]

A sensor (HL5) based on rhodamine 6G–en and 3-(3,5-dimethyl-pyrazol-1-ylmethyl)-2-hydroxy-5-methyl-benzaldehyde (HL4) has been developed for a highly sensitive and selective CHEF based recognition of trivalent metal ions M3+ (M = Al, Fe and Cr) over mono- and di-valent and other biologically abundant trivalent metal ions with prominent enhancement in absorption and emission intensities. A large enhancement of fluorescence intensities for Fe3+ (21 fold), Al3+ (14 fold) and Cr3+ (10 fold) was observed upon addition of 1.8 equivalents of these metals into the probe in methanol/H2O (1 : 1, v/v, pH 7.2) with the possibility of naked eye detection. The corresponding Kf values were evaluated to be 6.7 × 104 M−1 (Fe3+); 8.2 × 104 M−1 (Al3+) and 6.0 × 104 M−1 (Cr3+). The quantum yields of HL5 and [HL5–Fe3+] and [HL5–Cr3+] and [HL5–Al3+] complexes in methanol/H2O (1 : 1, v/v, pH 7.2) are found to be 0.013, 0.290, 0.120, and 0.158, respectively, using rhodamine-6G as the standard. The LOD for Fe3+, Al3+ and Cr3+ were determined by 3σ methods with values 0.29, 0.34 and 0.31 μM, respectively. An arsenate ion snatches Al from the Al–HL5 complex and quenches its fluorescence via its ring closed spirolactam form. Advanced level molecular logic devices using the inputs 2 and 4 and memory devices, have been constructed. The low cytotoxicity and large enhancement in fluorescence intensity of HL5 upon complexation with M3+ metal ions make the probe suitable for bio-imaging of M3+ (M = Al, Fe and Cr) in living cells and native cellular iron pools. [ABSTRACT FROM AUTHOR]

Background: Oral squamous cell carcinoma (OSCC) is one of the common malignancies in Southeast Asia. Epigenetic changes, mainly the altered DNA methylation, have been implicated in many cancers. Considering the varied environmental and genotoxic exposures among the Indian population, we conducted a genome-wide DNA methylation study on paired tumor and adjacent normal tissues of ten well-differentiated OSCC patients and validated in an additional 53 well-differentiated OSCC and adjacent normal samples. Results: Genome-wide DNA methylation analysis identified several novel differentially methylated regions associated with OSCC. Hypermethylation is primarily enriched in the CpG-rich regions, while hypomethylation is mainly in the open sea. Distinct epigenetic drifts for hypo- and hypermethylation across CpG islands suggested independent mechanisms of hypo- and hypermethylation in OSCC development. Aberrant DNA methylation in the promoter regions are concomitant with gene expression. Hypomethylation of immune genes reflect the lymphocyte infiltration into the tumor microenvironment. Comparison of methylome data with 312 TCGA HNSCC samples identified a unique set of hypomethylated promoters among the OSCC patients in India. Pathway analysis of unique hypomethylated promoters indicated that the OSCC patients in India induce an anti-tumor T cell response, with mobilization of T lymphocytes in the neoplastic environment. Survival analysis of these epigenetically regulated immune genes suggested their prominent role in OSCC progression. Conclusions: Our study identified a unique set of hypomethylated regions, enriched in the promoters of immune response genes, and indicated the presence of a strong immune component in the tumor microenvironment. These methylation changes may serve as potential molecular markers to define risk and to monitor the prognosis of OSCC patients in India. [ABSTRACT FROM AUTHOR]

Developing simple probes to sense Al 3+ in vivo and in vitro in real time is highly desirable as Al 3+ imbalance has been linked to a variety of diseases in human being. Here, we introduce a new, highly selective and sensitive Schiff base chemosensor, H 2 bpet , based on benzophenone that can detect Al 3+ in a 0.01% ethanol in 50 mM HEPES buffer medium by fluorimetric sensing. The structure of the probe, H 2 bpet involves existence of keto−–enol tautomerism. Single crystal X-ray diffraction study reveals prevalence of keto form of H 2 bpet in the solid state. The binding properties of H 2 bpet with Al 3+ was thoroughly investigated by fluorescence spectroscopy and ESI–MS analyses. The binding of Al 3+ to the probe H 2 bpet , induces distinct 1 H and 13 C NMR shifts in favour of H 2 bpet (keto form):Al 3+ aggregate. The sensing mechanism of H 2 bpet toward Al 3+ and composition of H 2 bpet:Al 3+ aggregate was proposed and established by DFT/TDDFT calculations. Its application in fluorescent imaging in HepG2 cells was also tested. This report demonstrates an advancement in detection of Al 3+ with the introduction of a new benzophenone containing Schiff base chemosensor. [ABSTRACT FROM AUTHOR]

A new 8-hydroxyquinoline-pyrazole based highly sensitive and selective Al3+ sensor, 8Q-NH-Pyz (H2L3), was found to exhibit a turn-on fluorescence enhancement (FE) as high as 157 fold with Kd = (1.76 ± 0.06) × 10−5 M. The 1 : 1 binding stoichiometry was revealed from the linear fit of (Fmax−F0)/(F−F0) vs. 1/[Al3+] of the fluorescence titration data which was further substantiated by Job's method and HRMS studies. The LOD determined by 3σ methods was found to be 4.29 nM and quantum yields were determined to be 0.002 and 0.28 for the ligand and its Al3+ complex, respectively. The tentative coordination environment in the [Al(L3)(H2O)]+ complex was delineated by DFT calculations. TDDFT calculations reveal spectral features comparable to the experimental ones. This constitutes the first report on the fluorescence sensing of Al3+ and hence F− in a purely aqueous medium. [ABSTRACT FROM AUTHOR]

Organic molecules with the possibility of logic operations are highly useful building blocks for the development of molecule-based “intelligent” devices for information processing applications. We have designed herein a very simple bio-friendly chemosensor (LC) equipped with a rhodamine fluorophore moiety. This probe showed a chromo-fluorescence response profile for Al3+but a colorimetric response for Cu2+metal. The absorption responses of LCcaused by these metal ions along with the “OFF–ON–OFF” fluorescence behavior of an LC–Al3+complex towards EDTA were employed for the development of a three-input and one output combinatorial molecular system. Interactions of the mentioned metal ions with LCin controlled sequential experiments gave fluorescence responses, enabling us to fabricate a ‘key-pad-logic’ function. So, a single molecular system performing such multiple ‘Boolean’ operations not only simplifies the complexity of a chemical driven ‘Intelligence’ device but also enriches the security of such a device against information invasion due to the sequence controlled sensor–analyte interactions and may find potential applications in biocompatible molecular logic platforms. [ABSTRACT FROM AUTHOR]