LL-00066471, a novel positive allosteric modulator of α7 nicotinic acetylcholine receptor ameliorates cognitive and sensorimotor gating deficits in animal models: Discovery and preclinical characterization

α7 nicotinic acetylcholine receptor (α7 nAChR) is an extensively validated target for several neurological and psychiatric conditions namely, dementia and schizophrenia, owing to its vital roles in cognition and sensorimotor gating. Positive allosteric modulation (PAM) of α7 nAChR represents an innovative approach to amplify endogenous cholinergic signaling in a temporally restricted manner in learning and memory centers of brain. α7 nAChR PAMs are anticipated to side-step burgeoning issues observed with several clinical-stage orthosteric α7 nAChR agonists, related to selectivity, tolerance/tachyphylaxis, thus providing a novel dimension in therapeutic strategy and pharmacology of α7 nAChR ion-channel. Here we describe a novel α7 nAChR PAM, LL-00066471, which potently amplified agonist-induced Ca2+ fluxes in neuronal IMR-32 neuroblastoma cells in a α-bungarotoxin (α-BTX) sensitive manner. LL-00066471 showed excellent oral bioavailability across species (mouse, rat and dog), low clearance and good brain penetration (B/P ratio > 1). In vivo, LL-00066471 robustly attenuated cognitive deficits in both procognitive and antiamnesic paradigms of short-term episodic and recognition memory in novel object recognition task (NORT) and social recognition task (SRT), respectively. Additionally, LL-00066471 mitigated apomorphine-induced sensorimotor gating deficits in acoustic startle reflex (ASR) and enhanced antipsychotic efficacy of olanzapine in conditioned avoidance response (CAR) task. Further, LL-00066471 corrected redox-imbalances and reduced cortico-striatal infarcts in stroke model. These finding together suggest that LL-00066471 has potential to symptomatically alleviate cognitive deficits associated with dementias, attenuate sensorimotor gating deficits in schizophrenia and correct redox-imbalances in cerebrovascular disorders. Therefore, LL-00066471 presents potential for management of cognitive impairments associated with neurological and psychiatric conditions.

Mimicking the Synaptic Weights and Human Forgetting Curve Using Hydrothermally Grown Nanostructured CuO Memristor Device

In the present investigation, we have fabricated copper oxide (CuO) thin film memristor by employing a hydrothermal method for neuromorphic application. The X-ray diffraction pattern confirms the films are polycrystalline in nature with the monoclinic crystal structure. The developed devices show analog memory and synaptic property similar to biological neuron. The size dependent synaptic behavior is investigated for as-prepared and annealed CuO memristor. The results suggested that the magnitude of synaptic weights and resistive switching voltages are dependent on the thickness of the active layer. Synaptic weights are improved in the case of the as-prepared device whereas they are inferior for annealed CuO memristor. The rectifying property similar to a biological neuron is observed only for the as-prepared device, which suggested that as-prepared devices have better computational and learning capabilities than annealed CuO memristor. Moreover, the retention loss of the CuO memristor is in good agreement with the forgetting curve of human memory. The results suggested that hydrothermally grown CuO thin film memristor is a potential candidate for the neuromorphic device development.

First Report of Leaf Spot Caused by Phoma costarricensis on Delphinium malabaricum in Western Ghats of India

Delphinium L. is a genus of more than 300 species of perennial flowering plants belonging to the family Ranunculaceae and is native throughout the Northern Hemisphere. In India, 24 species are found mainly in the Himalayan regions. Delphinium malabaricum (Huth) Munz is the only species of the genus endemic to northern Western Ghats. Its mediumsized violet-to-metallic blue spurred flowers have considerable ornamental value as a floriculture crop (3). There is no report of serious diseases of this genus in India. Since 2008, a severe foliar disease was observed each year on D. malabaricum cultivated on the experimental plots located at Shivaji University, Kolhapur, India. Symptoms were small, necrotic spots on the abaxial and adaxial sides of infected leaves, with spots enlarging to form round areas that were 6 to 9 mm in diameter and well defined by a dark black margin. Severely infected leaves wilted without abscising. No symptoms were observed on other plant parts. From infected leaves, a fungus was isolated on Czapek Dox agar (CDA) amended with 25 mg/liter of streptomycin sulfate. The fungus was grown on CDA and cultures were maintained at 4°C for further studies. After 6 days, black pycnidia developed, which were variable in size, releasing abundant hyaline, elliptical conidia measuring from 3 to 4 × 1.5 to 2 μm. On the basis of cultural and morphological characteristics, the fungus was identified as Phoma costarricensis (1,2). The identification was verified by sequencing a region of 28S ribosomal RNA with the geneOmbio LSU gene sequencing primers and ABI BigDye Terminator v3.1 Cycle Sequencing Reaction Kit (Applied Biosystems, Carlsbad, CA). The sequence was deposited as Accession No. HE608244 in EMBL-Bank. Blast analysis of the sequence obtained showed a 99% homology with several isolates of P. costarricensis in the GenBank database (Accession No. GU238058.1). Pathogenicity tests were performed by spraying leaves of 10 healthy plants with spores (~10,000 spores or mycelial fragments per ml) on the abaxial and adaxial surface of leaves. Noninoculated plants served as control. Symptoms identical to those on field samples developed on all inoculated plants 1 week after inoculation but controls remained asymptomatic during the observation period. P. costarricensis was reisolated from inoculated symptomatic plants and the identity was confirmed, which completed Koch's postulates. This experiment was repeated three times in a greenhouse, confirming the pathogenicity of P. costarricensis on D. malabaricum. P. ajacis (Thum.) Aa & Boerema, P. delphinii (Rabenh.) Cooke, P. aquilegiicola M. Petrov, and P. xanthina Sacc. are reported to cause leaf spot and stem rot in Delphinium spp. (1). However, to our knowledge, there are no previous reports of leaf spot of D. malabaricum caused by P. costarricensis. Leaf spot severity induced premature defoliation, leading to reduction in flower setting and ultimately the yield. The disease could lead to an economic crisis in the farmer community of western India. The only other known host of P. costarricensis is Coffea arabica (2). References: (1) G. H. Boerema et al. Phoma Identification Manual. CABI Publishing, Wallingford, UK and Cambridge, MA, 2004. (2) E. Echandi. Rev. Biol. Trop. 5:83, 1957. (3) S. R. Pai et al. Cytologia 72:319, 2007.

First Report of Aspergillus niger as a Plant Pathogen on Zingiber officinale from India

Zingiber officinale Rosc., belonging to the Zingiberaceae family, is medicinally important. It is commonly known as ginger and has been extensively cultivated for many centuries for use as a spice and traditional medicine in India. During a survey in September of 2007, leaves of Z. officinale showed a necrotic leaf spot disease on a plant growing in Kolhapur, India. Symptoms of the disease appeared as small (10 to 15 mm), rectangular to irregular, yellow spots on the leaves that covered a major area of the leaf when severe. The infection caused defoliation. Symptomatic leaves were collected and isolations from infected leaves were made on Czapek's Dox agar supplemented with streptomycin sulfate (30 mg/l). Plates were incubated at 28 to 30°C for 6 to 7 days. The fungal colonies were colorless to pale on the reverse side and covered with a dense layer of dark brown-to-black conidial heads. Conidia were globose to subglobose (3.5 to 5.0 μm in diameter), dark brown to black, and rough walled. 16S rRNA of isolates was amplified and sequenced (EMBL Accession No. AM941157) and compared with sequences of known Aspergillus species obtained from GenBank. The closest matches (99% identity) were with A. niger. On the basis of morphological and molecular approaches, the pathogen was confirmed as A. niger. Of five isolates, AN-5 was used for pathogenicity study. Koch's postulates were satisfied after reisolating the fungus from leaves inoculated with a conidial suspension that showed symptoms (6 days after inoculation) similar to the lesions observed on the leaves collected from Z. officinale. The tests were repeated three times in the greenhouse. Healthy, potted Z. officinale plants were grown in isolation after artificial inoculation with a suspension of spores (10,000 conidia per ml), which was prepared in 100 ml of sterile distilled water and then sprayed on the abaxial and adaxial surface of leaves. Noninoculated plants served as controls. These results confirmed the pathogenicity of A. niger on Z. officinale. To our knowledge, this is the first report of A. niger causing a disease on ginger (1). Reference: (1) G. N. Dake. J. Spices Aromatic Crops. 4:40, 1995.

Spherical crystallization of celecoxib

Celecoxib exhibits poor flow properties and compressibility. Spherical crystallization of celecoxib was carried out using the solvent change method. An acetone:dichloromethane (DCM):water system was used where DCM acted as a bridging liquid and acetone and water as good and bad solvent, respectively. Hydroxypropylmethylcellulose (HPMC) was used to impart strength and sphericity to the agglomerates. The effect of amount of bridging liquid and speed of agitation was studied using 3(2) factorial design. Primary properties of the agglomerates were evaluated by infrared spectroscopy, powder X-ray diffraction, and differential scanning calorimetry. The effect of variables on micromeritic, mechanical, compressional, and dissolution behavior was evaluated by response surface methodology. Particle size, bulk density, mean yield pressure (MYP), and drug release were found to be significantly affected by either of the two variables. Interaction of variables significantly affected the MYP.

Compatibility studies between carbamazepine and tablet excipients using thermal and non-thermal methods

Proper formulation is an important aspect of any dosage form design. As a part of preformulation studies, differential scanning calorimetry (DSC) was used to investigate the physicochemical compatibility between Carbamazepine and various excipients commonly used in tablet manufacturing, supported by Fourier transform infrared (FTIR) and x-ray powder diffraction (XRPD) studies. Compatibility studies were conducted on samples kept at room temperature and at an elevated temperature of 55 degrees C for 3 weeks. Carbamazepine was found to be compatible with all lactose-based components, such as Granulac 230, Flowlac 100, and Microcelac 100. Differential scanning calorimetry studies indicated incompatibility with mannitol, microcrystalline cellulose, starch, and stearic acid. However, XRPD and FTIR studies implied that all the above excipients are compatible with Carbamazepine. X-ray powder diffraction demonstrated incompatibility with stearic acid for samples stored at 55 degrees C for 3 weeks, indicative of formation of a solid solution. Thus, DSC being a thermal method of analysis should not be used singly to detect any inherent incompatibility. It has to be supported sufficiently by other non-thermal techniques, such as XRPD and FTIR.

Std1, a gene involved in glucose transport in Schizosaccharomyces pombe

A wild-type strain, Sp972 h-, of Schizosaccharomyces pombe was mutagenized with ethylmethanesulfonate (EMS), and 2-deoxyglucose (2-DOG)-resistant mutants were isolated. Out of 300 independent 2-DOG-resistant mutants, 2 failed to grow on glucose and fructose (mutants 3/8 and 3/23); however, their hexokinase activity was normal. They have been characterized as defective in their sugar transport properties, and the mutations have been designated as std1-8 and std1-23 (sugar transport defective). The mutations are allelic and segregate as part of a single gene when the mutants carrying them are crossed to a wild-type strain. We confirmed the transport deficiency of these mutants by [14C]glucose uptake. They also fail to grow on other monosaccharides, such as fructose, mannose, and xylulose, as well as disaccharides, such as sucrose and maltose, unlike the wild-type strain. Lack of growth of the glucose transport-deficient mutants on maltose revealed the extracellular breakdown of maltose in S. pombe, unlike in Saccharomyces cerevisiae. Both of the mutants are unable to grow on low concentrations of glucose (10 to 20 mM), while one of them, 3/23, grows on high concentrations (50 to 100 mM) as if altered in its affinity for glucose. This mutant (3/23) shows a lag period of 12 to 18 h when grown on high concentrations of glucose. The lag disappears when the culture is transferred from the log phase of its growth on high concentrations. These mutants complement phenotypically similar sugar transport mutants (YGS4 and YGS5) reported earlier by Milbradt and Hoefer (Microbiology 140:2617-2623, 1994), and the clone complementing YGS4 and YGS5 was identified as the only glucose transporter in fission yeast having 12 transmembrane domains. These mutants also demonstrate two other defects: lack of induction and repression of shunt pathway enzymes and defective mating.

Thin-layer chromatographic spray reagent for the screening of biological materials for the presence of carbaryl

A spray reagent for the detection of the carbamate insecticide carbaryl was developed, consisting of 1% ammonium cerium(IV) nitrate in 20% v/v hydrochloric acid. This reagent reacts with the hydrolysis product of carbaryl, 1-naphthol, and forms a violet complex. Other carbamate insecticides do not give similar coloured spots. Moreover, organophosphorus, organochlorine and pyrethroid insecticides and constituents of visceral extracts (amino acids, peptides, proteins, etc.) do not interfere. The sensitivity of the reagent is about 0.1 microgram.

Thin-layer chromatographic detection of pyrethroid insecticides containing a nitrile group

A spray reagent for the detection of pyrethroid insecticides containing a nitrile group by thin-layer chromatography is described. These insecticides on alkaline hydrolysis yield cyanide ion, which in turn reacts with copper(II) acetate and o-tolidine in an acetic acid medium to give a blue colour. Organochlorine, organophosphorus and carbamate insecticides do not interfere. The limit of detection is about 1 microgram.

Zinc chloride-diphenylamine reagent for thin layer chromatographic detection of some organophosphorus and carbamate insecticides

Zinc chloride-diphenylamine reagent, whose use has been reported for the detection of organochlorine insecticides by thin layer chromatography, was further studied for its ability to detect the organophosphorus insecticides phorate, phosphamidon, DDVP, and phosalone and the carbamate insecticide carbaryl and aldicarb. These insecticides give intense blue-green spots with this reagent. The procedure can be applied to the detection of the insecticides in biological materials and thus has a potential use in forensic toxicology.