Biodiesel production and optimization from Calophyllum inophyllum linn oil (honne oil) – A three stage method

The present work examines the production of a biodiesel from a non-edible oil namely honne oil (Calophyllum inophyllum linn). A three stage process viz., pre-treatment, alkali catalyzed transesterification and post treatment adopted for the production is discussed. The reaction parameters such as methanol to oil molar ratio, catalyst concentration, temperature and time have been optimized for the production of biodiesel. The yield of biodiesel from the honne oil under the optimized conditions is found to be 89%.     

184 Small molecule identification against novel MDRA protein of Mycobacterium tuberculosis

Mycobacterium tuberculosis (Mtb) is an obstinate pathogen causing tuberculosis (TB) in Homo sapiens. One third of the World population is affected by Mtb (James et al., 2008). The multidrug-resistant protein-A (MDRA) belongs to ABC transporter family. The protein MDRA and the membrane integral protein MDRB together form the efflux pump (MDRA₂B₂ complex) that confers resistance by transport of the drugs out of the cell. The MDRB protein expression depends on the expression of MDRA (Baisakhee et al., 2002). In the present study, MDRA 3-D model (Figure) was generated with the help of comparative homology modeling techniques using pair-wise sequence alignment. The predicted 3-D model was subjected to refinement and validated. The active site of the protein was predicted. The virtual screening (VS) studies were performed at MDRB binding site with an in-house library of small molecules to identify a lead molecule that can inhibits the MDRA protein. The results of VS project competitive inhibitors of MDRB, for its binding with MDRA, and its drug-resistant activity. Hence, the MDRA protein may be treated as a novel target for the development of new chemical entities for tuberculosis therapy (Bhargavi et al., 2010; Malkhed et al., 2011).     

Bifunctional glycosyltransferases catalyze both extension and termination of pectic galactan oligosaccharides

Pectins are the most complex polysaccharides of the plant cell wall. Based on the number of methylations, acetylations and glycosidic linkages present in their structures, it is estimated that up to 67 transferase activities are involved in pectin biosynthesis. Pectic galactans constitute a major part of pectin in the form of side‐chains of rhamnogalacturonan‐I. In Arabidopsis, galactan synthase 1 (GALS1) catalyzes the addition of galactose units from UDP‐Gal to growing β‐1,4‐galactan chains. However, the mechanisms for obtaining varying degrees of polymerization remain poorly understood. In this study, we show that AtGALS1 is bifunctional, catalyzing both the transfer of galactose from UDP‐α‐d ‐Gal and the transfer of an arabinopyranose from UDP‐β‐l ‐Ara_p to galactan chains. The two substrates share a similar structure, but UDP‐α‐d ‐Gal is the preferred substrate, with a 10‐fold higher affinity. Transfer of Ara_p to galactan prevents further addition of galactose residues, resulting in a lower degree of polymerization. We show that this dual activity occurs both in vitro and in vivo. The herein described bifunctionality of AtGALS1 may suggest that plants can produce the incredible structural diversity of polysaccharides without a dedicated glycosyltransferase for each glycosidic linkage.     

cAMP has distinct acute and chronic effects on aquaporin-5 in lung epithelial cells

Aquaporin-5 (AQP5) is present on the apical membrane of epithelial cells in various secretory glands as well as on the apical membrane of the airway epithelium, airway submucosal glands, and type 1 pneumocytes, where it can participate in respiratory tract water homeostasis. We examined the effects of cAMP on AQP5 distribution and abundance. When AQP5-expressing mouse lung epithelial cells were treated with cAMP or the beta-adrenergic agonist terbutaline, a biphasic AQP5 response was observed. Short term (minutes) exposure to cAMP produced internalization of AQP5 off of the membrane and a decrease in protein abundance. Both of these responses were blocked by inhibition of protein kinase A and the decrease in abundance was blocked by chloroquine, indicating lysosome-mediated degradation. Sustained cAMP exposure (hours) produced an increase in membrane localization and increased abundance; these effects were also blocked by protein kinase A inhibition. The beta-adrenergic agonist terbutaline produced changes in AQP5 abundance in mouse trachea and lung, consistent with our findings in cultured epithelial cells. Purified AQP5 protein was phosphorylated by protein kinase A but not protein kinase C or casein kinase II, and aquaporin-5 was phosphorylated in cultured cells after long term (but not short term) exposure to cAMP. These studies indicate that cAMP and beta-adrenergic agonists produce distinct short and long term effects on AQP5 distribution and abundance that may contribute to regulation of lung water homeostasis.     

Copper influenced changes of lipid metabolism in the tissues of freshwater teleost Labeo rohita (Hamilton).

Modulations in the lipid metabolism in the gill, liver, muscle and brain of freshwater teleost Labeo rohita exposed to 1, 2 and 3 days to lethal (1.2 mg/l) and 1, 15 and 30 days to sublethal (0.24 mg/l) concentrations of copper were studied. The total lipids decreased and there was an increase in the free fatty acids, glycerol and lipase activity in the organs studied at lethal concentration of copper. The degree in these shifts increased over time of exposure (1 less than 2 less than 3 days). In sublethal concentration, the levels of total lipids, free fatty acids, glycerol and lipase activity increased in all the four organs and the shifts followed two different trends during the exposure periods, 1 less than 15 less than 30 days in total lipids and 1 greater than 15 greater than 30 days in the other parameters. Among the organs, in both concentration media the changes in the lipid metabolism were in the order liver greater than gill greater than muscle greater than brain.     

A novel role for aquaporin-5 in enhancing microtubule organization and stability

Aquaporin-5 (AQP5) is a water-specific channel located on the apical surface of airway epithelial cells. In addition to regulating transcellular water permeability, AQP5 can regulate paracellular permeability, though the mechanisms by which this occurs have not been determined. Microtubules also regulate paracellular permeability. Here, we report that AQP5 promotes microtubule assembly and helps maintain the assembled microtubule steady state levels with slower turnover dynamics in cells. Specifically, reduced levels of AQP5 correlated with lower levels of assembled microtubules and decreased paracellular permeability. In contrast, overexpression of AQP5 increased assembly of microtubules, with evidence of increased MT stability, and promoted the formation of long straight microtubules in the apical domain of the epithelial cells. These findings indicate that AQP5-mediated regulation of microtubule dynamics modulates airway epithelial barrier properties and epithelial function.     

Recessive Mutations in SLC38A8 Cause Foveal Hypoplasia and Optic Nerve Misrouting without Albinism

Foveal hypoplasia and optic nerve misrouting are developmental defects of the visual pathway and only co-occur in connection with albinism; to date, they have only been associated with defects in the melanin-biosynthesis pathway. Here, we report that these defects can occur independently of albinism in people with recessive mutations in the putative glutamine transporter gene SLC38A8. Nine different mutations were identified in seven Asian and European families. Using morpholino-mediated ablation of Slc38a8 in medaka fish, we confirmed that pigmentation is unaffected by loss of SLC38A8. Furthermore, by undertaking an association study with SNPs at the SLC38A8 locus, we showed that common variants within this gene modestly affect foveal thickness in the general population. This study reveals a melanin-independent component underpinning the development of the visual pathway that requires a functional role for SLC38A8.     

Neuroprotective Effects of Bikaverin on H2O2-Induced Oxidative Stress Mediated Neuronal Damage in SH-SY5Y Cell Line

The generation of free radicals and oxidative stress has been linked to several neurodegenerative diseases including Parkinson’s disease, Alzheimer’s disease, Huntington’s disease, and Amyotrophic lateral sclerosis. The use of free radical scavenging molecules for the reduction of intracellular reactive oxygen species is one of the strategies used in the clinical management of neurodegeneration. Fungal secondary metabolism is a rich source of novel molecules with potential bioactivity. In the current study, bikaverin was extracted from Fusarium oxysporum f. sp. lycopersici and its structural characterization was carried out. Further, we explored the protective effects of bikaverin on oxidative stress and its anti-apoptotic mechanism to attenuate H₂O₂-induced neurotoxicity using human neuroblastoma SH-SY5Y cells. Our results elucidate that pretreatment of neurons with bikaverin attenuates the mitochondrial and plasma membrane damage induced by 100 µM H₂O₂ to 82 and 26 % as evidenced by MTT and LDH assays. H₂O₂ induced depletion of antioxidant enzyme status was also replenished by bikaverin which was confirmed by Realtime Quantitative PCR analysis of SOD and CAT genes. Bikaverin pretreatment efficiently potentiated the H₂O₂-induced neuronal markers, such as BDNF, TH, and AADC expression, which orchestrate the neuronal damage of the cell. The H₂O₂-induced damage to cells, nuclear, and mitochondrial integrity was also restored by bikaverin. Bikaverin could be developed as a preventive agent against neurodegeneration and as an alternative to some of the toxic synthetic antioxidants.     

Development of SCAR marker for sex identification in dioecious Garcinia gummi-gutta

Key message

We have developed sex-specific SCAR marker for the identification of dioecious Garcinia gummi - gutta (L.), which is useful for the selection of G. gummi - gutta at seedling stage and for plantation programmes.

Abstract

Garcinia gummi-gutta (L.) Robs. is a dioecious fruit yielding tree, which is naturally distributed as well as cultivated in the orchards in Western Ghat regions of India. A sex-linked DNA fragment was identified in Garcinia gummi-gutta (L.) Robs. by screening 150 randomly amplified polymorphic DNA primers and only one of them (OPBD20) showed different amplification band pattern associated with sex type. This sex-linked fragment was converted into male-specific sequence-characterized amplified region (SCAR) marker, CAM-566. The primers deigned in this study (OPBD20F and OPBD20R) correctly differentiated 12 male and 12 female plants at high annealing temperatures. Thus, a 556-bp band was amplified in male samples but not in female ones. Nevertheless, it should be noted that the fragments from both sexes were amplified at relatively low annealing temperatures. Additionally, the developed SCAR marker successfully identified the sexes of ten sex-unknown samples. Therefore, it can be used as an effective, convenient and reliable tool for sex determination in such dioecious species.