Interactions between metal oxides and biomolecules: from fundamental understanding to applications

Metallo-oxide (MO) based bioinorganic nanocomposites promise unique structures, physico-chemical properties and novel bio-chemical functionalities and within the last decade, investment in research on materials such as ZnO, TiO2, SiO2 and GeO2 has significantly increased. Besides traditional approaches, the synthesis, shaping, structural patterning and post-processing chemical functionalization of the materials surface is inspired by strategies which mimic processes in nature. Would such materials deliver new technologies? Answering this question requires the merging of historical knowledge and current research from different fields of science. Practically, we need an effective defragmentation of the research area. From our perspective, the superficial accounting of material properties, chemistry of the surfaces and the behaviour of biomolecules next to such surfaces is a problem. This is particularly of concern when we wish to bridge between technologies in vitro and biotechnologies in vivo. Further, besides the potential practical technological efficiency and advantages such materials might exhibit, we have to consider the wider long-term implications of material stability and toxicity. In this contribution we present a critical review of recent advances in the chemistry and engineering of MO based biocomposites highlighting the role of interactions at the interface and the techniques by which these can be studied. At the end of the article we outline the challenges which hamper progress in research and extrapolate to developing and promising directions including additive manufacturing and synthetic biology that could benefit from molecular level understanding of interactions occurring between inanimate (abiotic) and living (biotic) materials

Neonatal streptozotocin-induced rat model of Type 2 diabetes mellitus: A glance

Diabetes mellitus is a group of syndromes characterized by hyperglycemia, altered metabolism of lipids, carbohydrates and protein and an increased risk of complication of vascular diseases. Type 2 diabetes mellitus is characterized by derangement of insulin secretion and an inability of the peripheral tissues to respond to insulin. In spite of the availability of many animal models for Type 2 diabetes mellitus including genetic and chemically induced, none of them simulate human Type 2 diabetes mellitus. An attempt has been made in the present review, to evaluate the neonatal streptozotocin-induced rat (n-STZ rats) model of Type 2 diabetes mellitus, for its potential advantages as a suitable model over the others. The n-STZ model (with alteration of dose and day of STZ injection) exhibits various stages of Type 2 diabetes mellitus such as impaired glucose tolerance, and mild, moderate and severe glycemia. The cells in n-STZ rats bear a resemblance to insulin secretory characteristics found in patients with Type 2 diabetes mellitus. Thus the n-STZ model can be considered as one of the suitable animal models of Type 2 diabetes mellitus

Pharmacological investigations of Sapindus trifoliatus in various in vitro and in vivo models of inflammation

OBJECTIVE: To investigate the effect of lyophilized aqueous extract of pericarps of Sapindus trifoliatus (ST) in various in vitro and in vivo inflammatory models. METHODS: ST was studied for its in vitro inhibitory activity against 5-lipoxygenase (5-LO), cyclo-oxygenase (COX), leukotriene B4 (LTB4) and nitric oxide synthase (NOS). At doses 20 and 100 mg/kg, i.p. ST was evaluated in acute pedal inflammation induced by carrageenan, histamine, serotonin and zymosan in rats and mice. Further, the effect of topical application of the extract (1 mg and 5 mg) on ear inflammation induced by various inflammatory agents like -O-tetradecanoyl-phorbol 13-acetate (TPA) or capsaicin or arachidonic oxazolone or dinitrofluorobenzene (DNFB) was also investigated. RESULTS: In vitro evaluation of the extract revealed its inhibitory activity against the major inflammatory mediators 5-LO, COX, LTB4 and NOS. The extract significantly inhibited the pedal inflammation produced by carrageenan, histamine, serotonin and zymosan. Further, topical application of ST significantly inhibited the ear inflammation induced by acute and multiple applications of TPA and acute application of capsaicin or arachidonic acid. However, the extract failed to inhibit ear inflammation induced by oxazolone or DNFB. CONCLUSION: ST has antiinflammatory activity possibly mediated through 5-LO and COX pathways

Investigations of Sapindus trifoliatus in dopaminergic and serotonergic systems: Putative antimigraine mechanisms

OBJECTIVE: To evaluate the potential dopaminergic and serotonergic receptor-mediated modulatory effect of the aqueous extract of Sapindus trifoliatus [(ST), (family: Sapindaceae)], a traditional phytomedicine used in the treatment of hemicrania (migraine), using animal models and receptor assays. MATERIALS AND METHODS: ST (at 20 and 100 mg/kg, i.p. doses) was evaluated for its effect on apomorphine-induced climbing behavior, 5-hydroxytryptophan (l-5-HTP)-induced serotonin syndrome, and MK-801-induced hyperactivity in mice. The radioligand binding studies for various receptors and enzymes were carried out (outsourced) using standard procedures at 250 µg/ml concentration of ST. RESULTS: ST significantly inhibited the apomorphine-induced climbing behavior, the l-5-HTP-induced serotonin syndrome and MK-801-induced hyperactivity in mice. In the receptor radioligand binding studies, ST exhibited affinity towards dopamine D2, 5-HT2A receptors. CONCLUSION: The results of the behavioral studies in mice indicate that ST modulated D2 and 5-HT2A receptor-mediated paradigms. The radioligand binding studies supported these observations, suggesting the possible involvement of dopaminergic and serotonergic mechanisms in the antimigraine activity of ST

<span style="font-size:14.0pt;line-height: 115%;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:black;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">5-HT₃receptors in selective animal models of cognition</span>

174-180<span style="font-size:14.0pt;line-height: 115%;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" color:black;mso-ansi-language:en-in;mso-fareast-language:en-in;mso-bidi-language:="" hi"="" lang="EN-IN">Role of 5-HT3 receptors in cholinergic hypofunctional models of cognitive impairment in the elevated plus maze model and a passive avoidance model is studied. Cognitive impairment was caused by scopolamine (1 mg/kg, ip) in mice and 5-HT3 ligands mCPBG (1 and 5 mg/kg, ip) and ondansetron (0.5 and 5mg/kg, ip) were administered before the pre- learning phase to study the effects on acquisition, while post-learning administration was used to determine the effects on consolidation. Ondansetron improved acquisition and retention in cholinergic hypofunctional models while mCPBG potentiated selected impaired cognitive indices. The results indicate the role of 5-HT3 receptors in cognition and that an ideal evaluation of 5-HT3 ligands in cognition should distinguish true cognitive effects from locomotor, motivational and emotional effects<span style="font-size: 8.0pt;line-height:115%;font-family:" times="" new="" roman";mso-fareast-font-family:="" "times="" roman";color:black;mso-ansi-language:en-in;mso-fareast-language:="" en-in;mso-bidi-language:hi"="" lang="EN-IN">.</span

Synthesis of new fluorescently labeled glycosylphosphatidylinositol (GPI) anchors

The borondipyrromethene (BODIPY) labeled new glycosylphosphatidylinositol (GPI) molecules were synthesized as cellular probes to study the chemical basis of microdomain organization of GPI-anchored proteins and cholesterol in plasma membrane. The synthesis enabled by a new stereo-selective glycosylation of myo-D-inositol acceptor led to the preparation of optically pure glucosaminyl-(1-6)-a-phosphatidylmyo-D-inositol and its unnatural stereoisomer