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1,4-Diphenylbutadiene compounds, namely 1-p-cyanophenyl-4-phenylbuta-1E,3E-diene (2), 1-p-nitrophenyl-4-phenylbuta-1E,3E-diene (3), 1-cyano-1,4-diphenylbuta-1Z,3E-diene (4), 1-p-cyanophenyl-4-p-nit...

A fluorescence study of 1-p-cyanophenyl-4-phenylbuta-1E,3E-diene (2), 1-p-nitrophenyl-4-phenylbuta-1E,3E-diene (3), and 1-p-nitrophenyl-4-p-cyanophenylbuta-1E,3E-diene (4) in solvents of varying polarity at ambient temperature and in a 1:1 ethanol–methanol matrix at 298 and 77 K revealed that the nitro-substituted compounds are capable of exhibiting unusually red-shifted fluorescence emissions due to a twisted intramolecular charge transfer excited state.

Two new long chain tryptophan compounds viz [3-(indolyl-3′)-2-(N-octadecamido)]-methylpropionate (4) and sodium-[3-(indolyl-3′)-2-(N-octadecamido)]-propionate (5) have been prepared and their fluorescence properties (λmax, φf, τf, rss, quenching) have been investigated in homogeneous media and in phosphatidyl choline vesicles. Both 4 and 5 in a membrane mimicking system of phosphatidylcholine vesicles show blue-shifted emission maxima but higher quantum yields of fluorescence as compared to tryptophan. The steady state anisotropy values show that the molecules are immobilised in the membrane. While both the fluorophores show single exponential fluorescence decay profile in homogeneous media, a triple exponential fluorescence decay is observed in vesicular medium. The fluorescence of both the compounds are quenched by retinyl polyenes viz. retinal and retinyl acetate. The extent of quenching is more in organised media of vesicles as compared to organic solvents. A comparison of the fluorescence data for 4 and 5 with those for retinal-binding protein bacteriorhodopsin and the apoprotein bacterioopsin reveals some similarities in the nature of interaction between retinylidene polyenes and 4 and 5, and between retinylidene Schiff base chromophore and tryptophan residues in the protein., © Elsevier

Absorption and fluorescence studies of retinol (vitamin A alcohol) and retinol palmitate (vitamin A palmitate) intercalated in phosphatidylcholine (PC) liposomes show that these compounds are bound to the lipid bilayer. It is further found that retinol binds liposomes with greater affinity as compared to retinol palmitate. In addition, the delivery of liposome-incorporated retinoids to the blood has also been studied and it is found that these systems reduce blood viscosity and cause less lysis of red blood cells than retinoid compounds not complexed in liposomes., © Elsevier

Absorption spectral studies of all-trans-N-retinylidene-n-butylamine (1), all-trans-N-retinylidene-tryptamine (2) in various media (heptane, methanol, cellulose, cellulose acetate, ethylene glycol, polyethylene glycol, polyethylene, and polyvinyl alcohol) and in presence of various protonating agents (chloroacetic acid, 2-chloropropionic acid, perchloric acid) suggest that H-bond interactions play important role in regulating the absorption spectrum of retinylidene Schiff base chromophore. The results are discussed in terms of the characteristic absorption spectral properties of retinal based photoreceptor proteins. (C) Elsevier Science S.A.

Rates of hydrolysis of a model retinylidene Schiff base chromophore, namely all-trans-N-retinylidene-β-naphthylamine (1), have been determined in tetrahydrofuran, CHCl3, and CH3CN, in the presence and absence of metal cations (Li+, Mg2+) and trichloroacetic acid as the protonating agent. A mechanism for the hydrolysis of the Schiff base chromophore in visual pigments and a representation of the role of metal ions in maintaining the structure functions of bacteriorhodopsin have been proposed.

Dielectric constant and dielectric loss studies have been made on polycrystalline (with both random and partial grain orientation) and single-crystal samples of Bi2VO5.5. Both the dielectric constant and the dielectric loss decrease with increasing pressure for all the samples, although the decrease is appreciable in the case of partially grain oriented samples. On application of moderate pressures, unpoled single crystals exhibit ferroelectric hysteresis loops very similar to that of the electrically poled single crystals at room pressure. Similar behaviour has been observed in the case of random and partially grain oriented polycrystalline samples. Beyond about 2 GPa, the samples do not exhibit normal ferroelectric hysteresis loops.

Bacteriorhodopsin variants were generated by UV mutagenesis. The protein variants thus engineered were characterized for their UV-visible absorption, light induced proton release activity and photocycle kinetics (BR→M).

Fruit extract of Cupressus sempervirens (CS), which is used traditionally to treat Benign Prostatic Hyperplasia (BPH)-like urinary symptoms in patients, was scientifically validated for anti-BPH activity. The ethanolic fruit extract of CS inhibited proliferation of human BPH-stromal cells and the activity was localized to its chloroform-soluble, diterpene-rich fraction. Eight major diterpenes isolated from this fraction exhibited moderate to potent activity and the most active diterpene (labda-8(17),12,14-trien-19-oic acid) exhibited an IC50 of 37.5 μM (antiproliferative activity against human BPH-stromal cells). It significantly inhibited activation (phosphorylation) of Stat-3 in BPH-stromal cells and prevented transactivation of androgen sensitive KLK3/PSA and TMPRSS2 genes in LNCaP cells. Labda-8(17),12,14-trien-19-oic acid-rich CS fraction prevented prostatic hyperplasia in rat model and caused TUNEL labeling of stromal cells with lower expressions of IGF-I, TGF-ß and PCNA, and bcl-2/bax ratio. Human BPH tissues exhibited precise lowering of stromal component after incubation in labda-8(17),12,14-trien-19-oic acid, ex vivo. We conclude that labda-8(17),12,14-trien-19-oic acid contained in CS exhibits anti-BPH activity through inhibition of stromal proliferation and suppression of androgen action in the prostate, presenting a unique lead structure for further optimization of anti-BPH activity.

Self-assembled peptide based nanostructures gained enough popularity due to their easy biocompatibility and numerous potential applications. An excellent model of self-assembly of hydroxyethylamine based peptide nanostructures was synthesized and characterized by DLS and TEM. Spherical nano structures of I and III were observed with particle size ∼50 and ∼80 nm, respectively. Further, I and III were screened against anti-malarial target, falcipain-3 (FP3), a crucial cysteine protease involved as a major hemoglobinase of Plasmodium falciparum . Interestingly, compound III completely inhibited the activity of FP3. The effective concentration (1.5 μM) of III found to be more potent than I . This biochemical result was substantiated by molecular-docking studies indicating III to be best inhibitor of FP3. This is the first report showing that bis hydroxethylamine based peptide nanostructures could be very effective inhibitor of malarial cysteine proteases.

Chikungunya has emerged as one of the most important arboviral infection of global significance. Expansion of Chikungunya virus endemic areas can be ascribed to naive population, increasing vector population and adaptability of virus to new vector. In this study, a SYBR Green I based quantitative RT-PCR assay was developed. The assay was found to be 10-fold more sensitive than conventional RT-PCR and no cross reactivity was observed with related alphaviruses and flaviviruses. The detection efficiency of the assay was impervious to mosquitoes of different pool sizes. Vector surveillance has resulted in detection of CHIKV RNA in Aedes aegypti, confirming its vectorial potential for CHIKV in northern India. The assessment of the assay was further carried out by studying the competence of Indian Ae. aegypti for CHIKV, which revealed 100% infection rate and dissemination rate with 60% transmission rate. The replication kinetics of CHIKV in different anatomical sites of Ae. aegypti revealed highest titre at day 6 post infection in midgut and at day 10 post infection in saliva, legs and wings. The implementation of the assay in detecting lower viral load makes it a remarkable tool for surveillance of virus activity in mosquitoes.

Malaria represents the world’s greatest public health problem in terms of number of people affected, levels of morbidity and mortality in tropical and subtropical countries. Malaria parasites are members of the Apicomplexa, family of Plasmodiidae. Histidine-rich protein-II secreted by Plasmodium falciparum is known to be a compelling marker in malaria diagnosis and follow-up. In our present study, we have optimized the batch fermentation and downstream process for large scale production of recombinant P. falciparum HRP-II 62 kDa protein for diagnostic application. The culture broth was effectively induced with IPTG twice at different time intervals to sustain induction for a long period. Batch fermentation resulted in a wet weight of 61.34 g/L and dry cell biomass 12.81 g/L. With the improved downstream process, purified recombinant protein had a yield of 304.60 mg/L. The authenticity of the purified recombinant protein was confirmed via western blotting using indigenously developed HRP-II specific monoclonal antibodies and known positive human clinical sera samples. Further, the reactivity of recombinant HRP-II protein was validated using commercially available immuno chromatographic strips. Indirect ELISA using recombinant purified protein recognized the P. falciparum specific antibodies in suspected human sera samples. Our results clearly suggest that the recombinant HRP-II protein produced via batch fermentation has immense potential for routine diagnostic application.

The dielectric constants of lead iron niobate (PFN) and 40% lead zinc niobate (PZN) added to lead iron niobate (PFN0.6-PZN0.4) have been measured as a function of pressure up to 6 GPa under isothermal conditions between room temperature and 348 K. The relaxor transition temperature measured at 1 kHz excitation frequency varies at a rate −24.5 K/GPa for PFN and at a rate of −28.8 K/GPa for the PFN0.6-PZN0.4 composition.

All- trns -N-retinylidenetryptamine Schiff base was incorporated into aerosol-OT (AOT, sodium bis(2-ethylhexyl)sulphosuccinate)/heptane reverse micelles. This micellar system was used as a model to study the retinal-tryptophan interactions in retinal proteins. The retinylidene Schiff base remains stable in the presence of reverse micelle-solubilized water pools. Partition coefficient and microviscosity measurements show that the Schiff base is located in the micellar interphase. The results are discussed in terms of the interaction between the retinylidene chromophore and the active site environment of rhodopsin and bacteriorhodopsin. In the present model, the quencher and emitting units are covalently attached, and are separated by two carbon spacer units. The fluorescence emission data obtained for the micelle-intercalated Schiff base chromophore are compared with the fluorescence of the native protein and intermediates in the photochemical cycle of bacteriofhodopsin. A comparison of the data obtained for tryptamine and the Schiff base with the results available for bacteriorhodopsin and bacterioopsin reveals that there is a large degree of quenching on intercalation of the retinylidene chromophore in the vicinity of the fluorophore. Evidence provided by this model suggests that energy transfer to retinal can occur from tryptophan residues located in the retinal pocket in the native protein. Thus the retinylidene unit can act as a quencher of the energy of tryptophan, the nature and extent of which may depend on the conformation and relative orientation of the protein-bound fluorophore.

Chikungunya virus is now recognised as a resurging arbovirus of global public health significance, with their circulation in both new and old world. It is horizontally transmitted among vertebrates by Aedes mosquitoes. So far, the existence of vertical transmission of Chikungunya virus in Aedes vector is riddled with conflicting reports. In this study, presence of Chikungunya virus was detected in adult Aedes aegypti mosquitoes that emerged from field-collected larvae from Gwalior, northern India during 2010. This was further confirmed through nucleotide sequencing that revealed the presence of novel east central south African (ECSA) genotype of Chikungunya virus. This provides molecular evidence for vertical transmission of Chikungunya virus in mosquitoes in nature, which may have important consequences for viral survival during inter-epidemic period and adverse climatic conditions.

Bacillus anthracis, the causative agent of anthrax is one of the most important biological warfare agents. In this study, surface plasmon resonance (SPR) technology was used for indirect detection of B. anthracis by detecting protective antigen (PA), a common toxin produced by all live B. anthracis bacteria. For development of biosensor, a monoclonal antibody raised against B. anthracis PA was immobilized on carboxymethyldextran modified gold chip and its interaction with PA was characterized in situ by SPR and electrochemical impedance spectroscopy. By using kinetic evaluation software, KD (equilibrium constant) and Bmax (maximum binding capacity of analyte) were found to be 20 fM and 18.74, respectively. The change in Gibb’s free energy (∆G = −78.04 kJ/mol) confirmed the spontaneous interaction between antigen and antibody. The assay could detect 12 fM purified PA. When anthrax spores spiked soil samples were enriched, PA produced in the sample containing even a single spore of B. anthracis could be detected by SPR. PA being produced only by the vegetative cells of B. anthracis, confirms indirectly the presence of B. anthracis in the samples. The proposed method can be a very useful tool for screening and confirmation of anthrax suspected environmental samples during a bio-warfare like situation.

Dengue non-structural protein (NS1) is known to be protective antigen and also has immense application for serodiagnosis. Several serodiagnostic assays available for dengue viral infection are dependent on tissue culture-grown viral proteins. This task is unsafe, laborious, more expensive that makes it unsuitable for routine large-scale production. Although bacterial expression is relatively simple and easy for recombinant protein expression, it is more challenging to make NS1 protein with native structural and immunological features using bacterial expression system. We have successfully developed a method leading to the purification and refolding of recombinant dengue virus type 3 (DENV3) NS1. The gene encoding NS1 was amplified and cloned in pET28a (+) vector. In order to increase the purity of the recombinant NS1, the transgene was engineered to carry 6× Histidine tags at both N and C-terminal ends. The recombinant construct (pETNS1) was transformed into E. coli Rosetta-gami cells and the expression conditions viz IPTG concentration, media type, temperature, and harvest time were optimized. The size of the expressed protein was found to be ~45 kDa and the authenticity of the expressed protein was confirmed using anti-His and anti-NS1 monoclonal antibodies. The NS1 protein was purified under denaturing conditions, to attain the native conformation, NS1 protein was in vitro refolded and dialyzed. The refolded NS1 protein was detected by commercial Immuno chromatographic strip and NS1 specific monoclonal antibodies. IgM antibody capture ELISA was performed using refolded recombinant NS1 protein which recognized the IgM antibodies in dengue-positive samples of acute phase of infection. Our result suggests that rNS1 protein has immense diagnostic potential and can be used in developing point of care diagnostic assays.

Dengue fever virus transmitted by Aedes aegypti causes lethal mortalities of human beings, and, because of the lack of any vaccine, management of this vector, especially with phytochemicals, is essential. In the present investigation, the structure-activity relationship of monoterpenes and their acetyl derivatives was studied to identify structural features that are responsible for mosquitocidal activity.Derivatization of monoterpenes (eugenol, geraniol, linalool, L-menthol and terpeniole) followed by structure-activity relationship studies identified all five acetyl derivatives as having enhanced mosquitocidal activity against fourth-instar larvae of Aedes aegypti. Acetylation of the hydroxyl group in general increased activity in comparison with hydroxyl compounds. Based on LC50 values (ppm), the activities could be placed in the following order: eugenyl acetate (50.2)linalyl acetate (119.7)terpinyl acetate (287.1)menthyl acetate (308.4)geranyl acetate (325.5), as compared with monoterpenoids: eugenol (82.8)linalool (242.6)terpineol (331.7)L-menthol (365.8)geraniol (415.0). In eugenyl acetate, the presence of an aromatic ring and a side chain with an allylic double bond makes it most effective.Bioactive functional groups identified in the study may contribute to the understanding of larvicidal activity of acetyl derivatives and may help in the development of ecofriendly mosquito larvicidal compounds.

Brucellosis is a disease caused by bacteria belonging to the genus Brucella. It affects cattle, goat, sheep, dog and humans. The serodiagnosis of brucellosis involves detection of antibodies generated against the LPS or whole cell bacterial extracts, however these tests lack sensitivity and specificity. The present study was performed to optimize the culture condition for the production of recombinant Brucella melitensis outer membrane protein 28 kDa protein in E.coli via fed batch fermentation. Expression was induced with 1.5mM isopropyl β thiogalactoside and the expressed recombinant protein was purified using Ni-NTA affinity chromatography. After fed-batch fermentation the dry cell weight of 17.81 g/L and a purified protein yield of 210.10 mg/L was obtained. The purified Brucella melitensis recombinant Omp 28 kDa protein was analyzed through SDS- poly acrylamide gel electrophoresis and western blotting. The obtained recombinant protein was evaluated for its diagnostic application through Indirect ELISA using brucellosis suspected human sera samples. Our results clearly indicate that recombinant Omp28 produced via fed batch fermentation has immense potential as a diagnostic reagent that could be employed in sero monitoring of brucellosis.

Response gene to complement (RGC)-32 is a novel molecule that plays an important role in cell proliferation. We investigated the expression of RGC-32 in multiple sclerosis (MS) brain and in peripheral blood mononuclear cells (PBMCs) obtained from patients with relapsing–remitting multiple sclerosis. We found that CD3 + , CD68 + , and glial fibrillar acidic protein (GFAP) + cells in MS plaques co-localized with RGC-32. Our results show a statistically significant decrease in RGC-32 mRNA expression in PBMCs during relapses when compared to the levels in stable MS patients. This decrease might be useful in predicting disease activity in patients with relapsing–remitting MS. RGC-32 expression was also correlated with that of FasL mRNA during relapses. FasL mRNA expression was significantly reduced after RGC-32 silencing, indicating a role for RGC-32 in the regulation of FasL expression. In addition, the expression of Akt1, cyclin D1, and IL-21 mRNA was significantly increased during MS relapses when compared to levels in healthy controls. Furthermore, we investigated the role of RGC-32 in TGF-β-induced extracellular matrix expression in astrocytes. Blockage of RGC-32 using small interfering RNA significantly inhibits TGF-β induction of procollagen I, fibronectin and of the reactive astrocyte marker α-smooth muscle actin (α-SMA). Our data suggest that RGC-32 plays a dual role in MS, both as a regulator of T-cells mediated apoptosis and as a promoter of TGF-β-mediated profibrotic effects in astrocytes.

Variable-temperature X-ray diffraction studies of C70 suggest the occurrence of two phase transitions around 350 and 280 K where the high-temperature phase is fcc and the low-temperature phase is monoclinic, best described as a distorted hcp structure with a doubled unit cell; two like-phases (possibly hcp) seem to coexist in the 280-350 K range. Application of pressure gives rise to three distinct transitions associated with characteristic pressure coefficients, the extrapolated values of the transition temperatures at ambient pressure being around 340, 325 and 270 K. Pressure delineates closely related phases Of C70 just as in the case Of C60 which exhibits two orientational phase transitions at high pressures.

Currently available vaccines for the pandemic Influenza A (H1N1) 2009 produced in chicken eggs have serious impediments viz limited availability, risk of allergic reactions and the possible selection of sub-populations differing from the naturally occurring virus, whereas the cell culture derived vaccines are time consuming and may not meet the demands of rapid global vaccination required to combat the present/future pandemic. Hemagglutinin (HA) based subunit vaccine for H1N1 requires the HA protein in glycosylated form, which is impossible with the commonly used bacterial expression platform. Additionally, bacterial derived protein requires extensive purification and refolding steps for vaccine applications. For these reasons an alternative heterologous system for rapid, easy and economical production of Hemagglutinin protein in its glycosylated form is required. The HA gene of novel H1N1 A/California/04/2009 was engineered for expression in Pichia pastoris as a soluble secreted protein. The full length HA- synthetic gene having α-secretory tag was integrated into P. pastoris genome through homologous recombination. The resultant Pichia clones having multiple copy integrants of the transgene expressed full length HA protein in the culture supernatant. The Recombinant yeast derived H1N1 HA protein elicited neutralising antibodies both in mice and rabbits. The sera from immunised animals also exhibited Hemagglutination Inhibition (HI) activity. Considering the safety, reliability and also economic potential of Pichia expression platform, our preliminary data indicates the feasibility of using this system as an alternative for large-scale production of recombinant influenza HA protein in the face of influenza pandemic threat.

Voltage-gated potassium (K(v)) channels play an important role in the regulation of growth factor-induced cell proliferation. We have previously shown that cell cycle activation is induced in oligodendrocytes (OLGs) by complement C5b-9, but the role of K(v) channels in these cells had not been investigated. Differentiated OLGs were found to express K(v)1.4 channels, but little K(v)1.3. Exposure of OLGs to C5b-9 modulated K(v)1.3 functional channels and increased protein expression, whereas C5b6 had no effect. Pretreatment with the recombinant scorpion toxin rOsK-1, a highly selective K(v)1.3 inhibitor, blocked the expression of K(v)1.3 induced by C5b-9. rOsK-1 inhibited Akt phosphorylation and activation by C5b-9 but had no effect on ERK1 activation. These data strongly suggest a role for K(v)1.3 in controlling the Akt activation induced by C5b-9. Since Akt plays a major role in C5b-9-induced cell cycle activation, we also investigated the effect of inhibiting K(v)1.3 channels on DNA synthesis. rOsK-1 significantly inhibited the DNA synthesis induced by C5b-9 in OLG, indicating that K(v)1.3 plays an important role in the C5b-9-induced cell cycle. In addition, C5b-9-mediated myelin basic protein and proteolipid protein mRNA decay was completely abrogated by inhibition of K(v)1.3 expression. In the brains of multiple sclerosis patients, C5b-9 co-localized with NG2(+) OLG progenitor cells that expressed K(v)1.3 channels. Taken together, these data suggest that K(v)1.3 channels play an important role in controlling C5b-9-induced cell cycle activation and OLG dedifferentiation, both in vitro and in vivo.

An equation has been derived for the lattice strain that corresponds to the strain measured by X-ray diffraction in a specimen compressed non-hydrostatically in a diamond anvil cell. This equation has been used to discuss the observed difference between the volume compressions of C60 fullerite measured under non-hydrostatic and hydrostatic pressure conditions.

The pressure (0·28–0·69 GPa)–temperature (382–409 K) dependence of the kinetics of the crystallization of amorphous Se to the trigonal phase has been investigated. The crystallized fraction-time data under different isobaric-isothermal conditions have been obtained, by monitoring the time dependence of the volume change, using the piston-displacement technique. The temperature dependence of the spherulitic growth rate g at different pressures has also been measured by optical microscopy. The isothermal rate of crystallization is found to increase with increase in temperature and to decrease with increase in pressure. The temperature dependences of the incubation period, the time t0·5 for 50% crystallized fraction and g at each pressure have been used to determine the activation energy barriers for nucleation, for overall crystallization and for the growth processes. Ali these energies correspond to the activation energy ΔG∗d for the diffusion process involved in the nucleation of spherulites. ΔG∗...

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system that is mediated by activated lymphocytes, macrophages/microglia, and complement. In MS, the myelin-forming oligodendrocytes (OLGs) are the targets of the immune attack. Experimental evidence indicates that C5b-9 plays a role in demyelination during the acute phase of experimental allergic encephalomyelitis (EAE). Terminal complement C5b-9 complexes are capable of protecting OLGs from apoptosis. During chronic EAE complement C5 promotes axonal preservation, remyelination and provides protection from gliosis. These findings indicate that the activation of complement and C5b-9 assembly can also have protective roles during demyelination.

Interaction of 3-styrylindoles 1-8 viz. 3-(2-phenylethenyl-E)-NH-indole (1), 3-[2-(4-nitrophenyl)ethenyl-E]-NH-indole (2), 5-bromo-3-[2-(4-nitrophenyl)ethenyl-E]-NH-indole (3), 5-methoxy-3-[2-(4-nitrophenyl)ethenyl-E]-NH-indole (4), 3-[2-(4-cyanophenyl)ethenyl-E]-NH-indole (5), 3-[2-(4-cyanophenyl)ethenyl-E]-N-ethylindole (6), 5-bromo-3-[2-(4-chlorophenyl)ethenyl-E]-NH-indole (7) and 5-methoxy-3-[2-(4-chlorophenyl)ethenyl-E]-NH-indole (8) with bovine serum albumin (BSA) was examined by UV-vis and steady-state fluorescence spectroscopy. The fluorescence intensity of 1-8 increases with the increasing BSA concentration. Upon binding with BSA, while 1 and 5-8 show a blue shift in their lambda(f max), 2-4 do not exhibit such behavior. Compounds 1-8 also quench the 345 nm fluorescence of BSA in phosphate buffer (lambda(ex), 280 nm). These compounds intercalate in the hydrophobic regions of BSA, as evidenced by the determination of BSA binding site micropolarity using compounds 2-8. As evidenced by the estimation of energy transfer efficiency and distance between the donor (BSA-Trp-212) and the acceptor (3-styrylindoles), the halo-substituted compounds 3 and 7 interact with BSA more effectively than the other 3-strylindoles. These compounds have potential for use as neutral and hydrophobic fluorescence probes for examining the microenvironments in proteins, polymers, micelles, etc.

Experimental studies (Bishop 1966) show that for saturated normally consolidated clay the cohesion varies linearly with depth. The ultimate bearing capacity in such soil is generally obtained by limit equilibrium and limit analysis methods. Sokolovski's (1960) approach to the method of characteristics is used to find the ultimate bearing capacity of saturated clay whose cohesion is homogeneous and isotropic. In this technical note, the method of characteristics is further developed to determine ultimate bearing capacity of clay whose cohesion varies linearly with depth.

Fluorescence properties of fluorescamine-modified bacteriorhodopsin (BR) have been studied. BR reacts with fluorescamine (1:2 ratio) to give protein (FLBR-I) modified at Lys-129. By making use of citraconic anhydride as a masking reagent, fluorescamine modification of Lys-40/41 in BR has been achieved. Forster's resonance energy transfer studies indicate that the distance between FL-Lys-129 and retinylidene chromophore is 11 angstrom, whereas that between FL-Lys-40/41 and retinylidene chromophore is 24 angstrom. These measured distances have been analysed in terms of BR structure.

Resistin, a small secreted peptide initially identified as a link between obesity and diabetes in mice, was shown to be involved in mediating inflammation in humans. We had shown earlier that recombinant human resistin has a tendency to form aggregates by formation of inter/intramolecular disulfide linkages and that it undergoes a concentration-dependent conformational change in secondary structure from alpha-helical to beta-sheet form. Here we report that this change in secondary structural conformation is due to the increase in the oligomeric form of human resistin as a function of protein concentration. Gel filtration analysis under different conditions further demonstrated that recombinant human resistin exists as a mixture of oligomer and trimer but is converted to a mixture of monomer and oligomer in the presence of 100 mM NaCl. We show that while the trimeric form of human resistin is stable to urea-induced denaturation, it is highly susceptible to NaCl and NaF, indicating the importance of ionic interactions in stabilization of trimer. In addition, urea was able to destabilize the oligomers indicating the involvement of hydrophobic interactions in oligomerization. Ionic as well as hydrophobic interactions stabilize the monomeric human resistin. Our data suggest that human resistin exists predominantly as oligomer and trimer in vitro. The oligomeric form of human resistin shows more potent effect on stimulation of proinflammatory cytokines. Therefore, it is very tempting to propose that the structural conformation of resistin may be involved in maintaining the very fine balance in regulation of macrophage function for successful response to a variety of pathological conditions.

All-trans-retinal (1) was reacted with n-butylamine in sodium bis(2-ethylhexyl)sulfosuccinate (AOT) reverse micelles in heptane to form all-trans-N-retinylidene–n-butylamine Schiff bases (2). The extent of protonation of 2 by 3-chloropropionic acid (CPA) to give 3 in AOT reverse micelles in heptane was found to depend on the ratio of [CPA] to [2], as well as on [H2O]/[AOT] (i.e., on the ω value). At any given [2] and ω values, increasing amounts of CPA increased the protonation and at any given constant [2] and [CPA], increasing ω values also increased the protonation. Over a period of 24 hours, there was only 4% decomposition of 2 in AOT reverse micelles in heptane at ω = 24. Conversely, in three hours, 23% of 3 decomposed in the same system. The trans to cis photoisomerization of 2 in heptane occurred at a much faster rate in the presence of AOT reverse micelles than in their absence. The appearance of carboxylate peaks (FTIR, 1400–1500 cm−1) indicated that the larger the AOT solubilized water pools, the greater the CPA dissociation. 1 also reacted with the α-NH2 group of l-lysine (4) in AOT reverse micelles in heptane to give the corresponding Schiff base 6. Protonation of 6 occurred either intramolecularly or by reaction with unreacted 4. These results were discussed in terms of rhodopsin protonations. Keywords: retinylidene Schiff bases, reverse micelles, protonation of Schiff bases, trans to cis photoisomerization.

Dodecylammonium glutamate (4) has been prepared from dodecylamine (2) and l-glutamic acid (3) in ethanol and in aqueous ethanol. The obtained crystalline glutamic acid salt of dodecylamine (4) has been characterized by absorption, FTIR, 1H NMR, 13C NMR, and mass spectroscopy. Reaction of all-trans retinal (5) with the α-amino group of 4 gave a Schiff base (6), which was protonated by the α-COOH group of the glutamyl residue. However, the protonated Schiff base underwent acid-catalyzed hydrolysis to 2 + 3 + 5. Some of 5 reacted with 2 to give the corresponding Schiff base. The proposed structures have been substantiated by insitu absorption, FTIR, and 1H NMR spectroscopy. Keywords: retinal Schiff base, retinal, rhodopsin model, dodecylammonium glutamate, Schiff-base protonation.

The fluorescence properties of 9-anthraldehyde ( 1 ) and 3-methyl-5-(9-anthryl)-2 E ,4 E -pentadienal ( 2 ) in organic ( n -hexane, tetrahydrofuran, n -butanol) and micellar (Triton-X-100 in water) environments are described. The fluorescence efficiency Φ f of 1 (0.38) is approximately ten times larger than that of 2 (0.035). Fluorescence quenching of 1 and 2 with N,N -dimethylaniline (DMA) was also studied. Compound 1 exhibits exciplex formation with DMA in organic solvents. Exciplex formation between compound 2 and DMA is only seen in non-polar solvents. The fluorescence lifetime τ of 2 is very similar in different media. Thus the lifetime τ of compound 2 in n -butanol (14.78 ns) is similar to that in Triton-X-100 (14.45 ns). Stern—Volmer analyses of quenching data indicate a dynamic quenching mechanism with a quenching rate constant of 1.23 × 10 9 M −1 s −1 . The fluorophores are likely to have a polar, viscous micro-environment.

Preparation and properties of the bacteriorhodopsin (bR) analogue having the 3,7-dimethyl-9-(9-anthryl)-2E,4E,6E,8E-nonatetraenal (12) chromophore is described. Synthesis of the chromophore has been achieved by successive introduction of C5 units to 9-anthraldehyde (3) via the Horner reaction. The all-trans chromophore has been characterized by its ultraviolet–visible and 1H nuclear magnetic resonance spectra. Incubation of 12 with bacterioopsin suspension (prepared by photobleaching of bR isolated from Halobacteriumhalobium) at ambient temperature in the dark gave the new bR analogue 15, which showed an absorption band at 545 nm, and an opsin shift of 5575 cm−1. The new pigment is stable to hydroxylamine in the dark. It showed light–dark adaptation with the light-adapted form absorbing at a slightly red-shifted value of 550 nm. All-trans-retinal did not replace the anthryl chromophore in competitive bindings. Photolysis of the bR analogue 15, followed by difference spectrophotometric analysis, indicated formation of a photoproduct with an absorption band near 400 nm. The results are discussed in terms of the stereoelectronic requirements of the bR reaction centre. Keywords: bacteriorhodopsin (bR), retinal analogue, reconstitution, opsin shift (OS), external point charge model (EPC).

In this paper are presented absorption and fluorescence emission properties of 3-styrylindoles viz. 3-(2-phenylethenyl-E)-NH-indole (1), 3-[2-(4-nitrophenyl)ethenyl-E)-NH-indole (2), 3-[2-(4-cyanophenyl)ethenyl-E]-N-ethylindole (3) and 3-[2-(4-cyanophenyl)ethenyl-E]-NH-indole (4) in organic solvents, 1,4-dioxane-water binary mixtures and micelles (SDS, CTAB and Triton-X-100). The fluorescence properties of 2-4 have been utilized to probe the microenvironment (binding constant, CMC, micropolarity and solubilization site) of the micelles.

Irradiation (λ ~ 350 nm in an aqueous environment) of carboxylic acid esters derived from the reaction between carboxylic acids and 2-bromo-1-(naphthalene-2-yl)ethanone affords the parent carboxylic acid in good yield, making the 2-acetonaphthyl chromophore a good phototrigger for caging applications, including biomolecular caging., © Elsevier

A novel class of phthalimides functionalized with privileged scaffolds was designed, synthesized and evaluated as potential inhibitors of plasmepsin 2 (Ki: 0.99 ± 0.1 μM for 6u) and plasmepsin 4 (Ki: 3.3 ± 0.3 μM for 6t), enzymes found in the digestive vacuole of the plasmodium parasite and considered as crucial drug targets. Three compounds were identified as potential candidates for further development. The listed compounds were also assayed for their antimalarial efficacy against chloroquine (CQ) sensitive strain (3D7) of Plasmodium falciparum. Assay of twenty seven hydroxyethylamine derivatives revealed four (5e, 6j, 6o and 6s) as strongly active, which were further evaluated against CQ resistant strain (7GB) of P. falciparum. Compound 5e possessing the piperidinopiperidine moiety exhibited promising antimalarial activity with an IC50 of 1.16 ± 0.04 μM. Further, compounds 5e, 6j, 6o and 6s exhibited low cytotoxic effect on MCF-7 cell line. Compound 6s possessing C 2 symmetry was identified as the least cytotoxic with significant antimalarial activity (IC50: 1.30 ± 0.03 μM). The combined presence of hydroxyethylamine and cyclic amines (piperazines and piperidines) was observed as crucial for the activity. The current studies suggest that hydroxyethylamine based molecules act as potent antimalarial agent and may be helpful in drug development.

We report here a case of 18 year old male with tremors of hands, deafness, tendency to fall while walking, drowsiness and double vision of total duration 1(1/2) years. He had internuclear ophthalmoplegia, broken saccades, hypertonia and hyperreflexia of all four limbs, intention tremors, signs of gait and limb ataxia. Pupillary reactions and fundus examination were normal and signs of meningeal irritation or sensory neurological deficit were absent. MRI head and cervical spine with gadolinium enhancement revealed demyelination as evident from multiple oblong foci isointense on T1-weighted images and hyperintense on T2-weighted and fluid attenuated inversion recovery sequences in corpus callosum, sub-cortical white matter, right thalamus, pons and periaqueductal region of midbrain. Ill-defined linear hyperintense signals were observed in cervical spinal cord. No skeletal abnormality was noted in the skull or cervical spine. Oligoclonal bands were present in the cerebrospinal fluid. Brainstem auditory evoked potentials were abnormal, although visual evoked potentials were in normal range. A diagnosis of primary progressive multiple sclerosis (PPMS) was made fulfilling the revised criteria as laid down. In view of its presentation, it is a unique case of PPMS from India.

Development of bacteriorhodopsin (bR) analogues employing chromophore substitution technique for the purpose of characterizing the binding site of bR and generating bR analogues with novel opto-electronic properties for applications as photoactive element in nanotechnical devices are described. Additionally, the photophysical and photochemical properties of variously substituted diarylpolyenes as models of photobiologically relevant linear polyenes are discussed. The role of charge separated dipolar excited states in the photoprocesses of linear polyenes is highlighted.

Photocleavable protecting groups are important in synthesis and caging. Among many such groups, 2-nitrobenzyl and related groups have been found useful in many applications. However, most of the known 2-nitrobenzyl-based caging chromophores show either low quantum yield or the photolysis wavelength is not suitable for various applications. In this paper, we report 2-nitro-3-naphthalenemethanol (NNM) as an efficient photocleavable protecting group for molecules containing a carboxylic function. NNM possesses photochemical properties better than the 2-nitrobenzyl chromophores as it is photoactivatable at 380 nm in aqueous medium (CH3CN/H2O, 3:2 v/v) showing the desired photochemistry. The carboxylic acids are efficiently photoreleased from NNM-based esters in almost quantitative yield., © Elsevier

While 3-(4-nitrophenyl ethenyl-E)-N-H indole is photochemi­ cally stable, and shows dramatically red-shifted solvatochromic nuorescence emission Ocm 642 nm with Acx 405 nm in acetoni­ trile), the corresponding p-aminophenyl derivative, 3-(4-amino phenyl cthcnyi-£)-N-H indole undergoes photocyelodehydrogena­ tion yielding a bcnzocarbazole photoproduct together with a mod­ erately red-shifted nuorcscence emission O'"cm 404/414 nm with An 323 nm in acetonitrile).

Chromophore-modified bacteriorhodopsin (bR) analogs are prepared, to study the nature of chromophore-protein interaction as well as to develop new bR analogs that can find applications as photoactive element in molecular electronic devices. This article describes the preparation and characterization of hitherto unknown bR analogs based on diphenylpolyene chromophores. Diphenylpolyene compounds, namely, 4-[(E)-2-phenylvinyl]benzaldehyde (1), 3-methyl-5-[4-[(E)-2-phenylvinyl]phenyl]penta-2E,4E-dienal (2), 4-[4-phenylbuta-1E,3E-dienyl]benzaldehyde (3) and 3-methyl-5-[4-[4-phenylbuta-lE,3E-dienyl]phenyl]penta-2E,4E-dienal (4), have been synthesized, and their interaction with bacterioopsin (bOP) has been studied. Whereas aldehydes 2 and 4 interact with bOP and yield bR analogs bR-2 and bR-4, aldehydes 1 and 3 do not yield any pigment. Analogs bR-2 and bR-4 have been characterized for their opsin shift, competitive binding, photochemical properties and fluorescence spectral behavior.

Resistin, a small cysteine rich protein secreted by adipocytes, has been proposed to be a link between obesity and type II diabetes by modulating the insulin signaling pathway and thus inducing insulin resistance. Resistin protein, with 11 cysteine residues, was not significantly homologous at the amino acid level to any other known cysteine rich proteins. Resistin cDNA derived from human subcutaneous adipose tissue was expressed in Escherichia coli as an N-terminal six-His-tag fusion protein. The overexpressed recombinant resistin was purified to homogeneity from inclusion bodies, after solubilization in 8 M urea, using a metal affinity column. While MALDI-TOF mass spectrometric analysis of the purified protein generated a single peak corresponding to the estimated size of 11.3 kDa, the protein exhibited a concentration-dependent oligomerization which is evident from size exclusion chromatography. The oligomeric structure was SDS-insensitive but beta-mercaptoethanol-sensitive, pointing to the importance of disulfide linkages in resistin oligomerization. Estimation of free cysteine residues using the NBD-Cl assay revealed a concentration- and time-dependent increase in the extent of formation of disulfide linkages. The presence of intermolecular disulfide bond(s), crucial in maintaining the global conformation of resistin, was further evident from fluorescence emission spectra. Circular dichroism spectra revealed that recombinant resistin has a tendency to reversibly convert from alpha-helical to beta-sheet structure as a direct function of protein concentration. Our novel observations on the biophysical and biochemical features of human resistin, particularly those shared with prion proteins, may have a bearing on its likely physiological function.

OBJECTIVE: Tuberculous atlantoaxial dislocation is a rare disease entity. However, tuberculosis continues to be endemic in developing countries. Its earliest clinical presentation may be nonspecific, and delay in diagnosis may lead to irreversible neurological deficit. The management of tuberculous atlantoaxial dislocation includes ventral cervicomedullary decompression, occipitocervicol arthrodesis, and administration of antituberculous medications. METHODS: Eighteen patients with tuberculous atlantoaxial disfocation who presented with neck pain and/or occipital headache, restriction of neck movement, difficulty swallowing, and signs of myelopathy were studied. Four patients had evidence of associated pulmonary tuberculosis. Plain x-rays of the cervical spine, computed tomographic scans, and magnetic resonance images were obtained in all patients for diagnosis and to assess the degree of dislocation and cervicomedullary compression. Simultaneous anterior neural decompression, via a trarnscervical retropharyngeal approach, and posterior arthrodesis were performed on all patients while they remained under anesthesia. Antituberculous chernotherapy was continued for 18 months. RESULTS: Histopathological analysis of excised tissue was consistent with tuberculosis in all patients. However, Ziehl-Neeisen staining for acid-fast bacilli was positive in two cases, and culture for Mycobacterium tuberculosis was negative in all patients. Patients with severe myelopathy experienced marked improvement. One patient died of fulminant resistant tuberculous meningitis. CONCLUSION: The transcervical retropharyngeal approach to the craniovertebral junction provides direct access to the lesion and avoids the potential bacterial contamination of the oral and pharyngeal cavity. It also prevents the development of persistent fistulae. Posterior stabilization should be performed directly after anterior neural decompression, while the patient remains under anesthesia, to prevent neurological deterioration before subsequent posterior fixation. This technique also is help-ful for early mobilization of patients. The aim of surgical treatment should be to obtain biopsy tissue and to perform radical excision of epidural granulation tissue/abscess and infected bone using microsurgical technique. Antituberculous medication must be continued for 18 months with four drug regimens, and continuous monitoring of drug toxicity should be performed throughout the course of treatment.

This paper reports absorption and fluorescence spectral studies of methyl 4-[(1E,3E)-4-phenylbuta-1,3-dienyl]benzoate (1), N,N-dimethyl-N-{4-[(1E,3E)-4-phenylbuta-1,3-dienyl]phenyl}amine (2), methyl 4-{(1E,3E)-4-[4-(dimethylamino)phenyl]buta-1,3-dienyl}benzoate (3) and 1-methyl-4-{(1E,3E)-4-[4-methoxyphenyl]buta-1,3-dienyl}benzoate (4) in homogeneous media of 1,4-dioxane and 1,4-dioxane–water binary mixtures, and in microheterogeneous media of cetyl trimethyl ammonium bromide (CTAB), sodium dodecyl sulfate (SDS) and Triton-X-100 micelles, and dipalmotoyl phosphatidylcholine (DPPC) vesicles. The binding site of the diene probes in micelles and vesicles has been determined and it has been found that while in micelles dienes occupy the polar interfacial regions, in vesicles the probes are located deep inside the hydrophobic bilayer. The binding of dienes to the vesicles is stronger than their binding to the micelles as indicated by the binding constant values. The fluorescence emission of the probe dienes in micelles is from a conformationally relaxed intramolecular charge transfer excited state. However, in vesicles, since the excited state conformational motions are restricted due to the rigidity of the alkyl chain, the dienes fluoresce from their planar locally excited states., © Elsevier

We have studied a computer simulations of the surface structure and chemical composition in NiAl for three low index surface orientations and three bulk compositions. We have applied a grand canonical Monte Carlo method in conjuction with a embedded atom potential fit to a large database. We found that the chemical composition of the (110) surface is very close to the bulk composition. For the (100) and (111) surface orientations, the Al termination contains some percentage of Ni atoms in the form of antisites and for the (111) orientation also a significant amount of surface vacancies and adatoms exist. The Ni termination of both surfaces are unstable and transform to Al terminations.