A novel approach for the biosynthesis of silver nanoparticles using the defensive gland extracts of the beetle, Luprops tristis Fabricius.

Discovering novel natural resources for the biological synthesis of metal nanoparticles is one of the two key challenges facing by the field of nanoparticle synthesis. The second challenge is a lack of information on the chemical components needed for the biological synthesis and the chemical mechanism involved in the metal nanoparticles synthesis. In the current study, microwave-assisted silver nanoparticle (AgNP) synthesis employing the defensive gland extract of Mupli beetle, Luprops tristis Fabricius (Order: Coleoptera; Family: Tenebrionidae), addresses these two challenges. This study was conducted without killing the experimental insect. Earlier studies in our laboratory showed the presence of the phenolic compounds, 2,3-dimethyl-1,4-benzoquinone, 1,3-dihydroxy-2-methylbenzene, and 2,5-dimethylhydroquinone in the defensive gland extract of L. tristis. The results of the current study show that the phenolic compounds in the defensive gland extract of the beetle has the ability to reduce silver ions into AgNPs and also acts as a good capping and stabilizing agent. A possible mechanism for the reduction of silver nitrate (AgNO3) into AgNPs is suggested. The synthesized AgNPs were characterized by Ultraviolet-Visible (UV-Vis) spectroscopy, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy energy-dispersive X-ray (SEM-EDX) analysis and high-resolution transmission electron microscopic (HR-TEM) techniques. The stability of biologically synthesized nanoparticles was studied by zeta potential analysis. The TEM analysis confirmed that AgNPs are well dispersed and almost round shaped. The average size of nanoparticle ranges from 10 to 20 nm. EDX analysis showed that silver is the prominent metal present in the nanomaterial solution. The AgNPs synthesized have antibacterial property against both Staphylococcus aureus and Escherichia coli. Radical scavenging (DPPH) assay was used to determine the antioxidant activity of the AgNPs. AgNPs exhibited anticancer activity in a cytotoxicity experiment against Dalton's lymphoma ascites (DLA) cell line.

Green Synthesis of Silver Nanoparticles Using the Leaf Extract of the Medicinal Plant, Uvaria narum and Its Antibacterial, Antiangiogenic, Anticancer and Catalytic Properties.

Silver nanoparticles (AgNPs) made by green synthesis offer a variety of biochemical properties and are an excellent alternative to traditional medications due to their low cost. In the current study, we synthesised AgNPs from the leaf extract of the medicinal plant Uvaria narum, commonly called narumpanal. The nanoparticles were characterised by ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM analysis showed AgNPs are highly crystalline and spherical with an average diameter of 7.13 nm. The outstanding catalytic activity of AgNPs was demonstrated by employing the reduction of 4-nitrophenol to 4-aminophenol. The AgNPs showed antiangiogenic activity in the chick chorioallantoic membrane (CAM) assay. AgNPs demonstrated anticancer activity against Dalton's lymphoma ascites cells (DLA cells) in trypan blue assay and cytotoxicity against three fish cell lines: Oreochromis niloticus liver (onlL; National Repository of Fish Cell Lines, India (NRFC) Accession number-NRFC052) cells, Cyprinus carpio koi fin (CCKF; NRFC Accession number-NRFC007) cells and Cyprinus carpio gill (CyCKG; NRFC Accession number-NRFC064). Furthermore, the AgNPs demonstrated their ability to inhibit pathogenic microorganisms, Staphylococcus aureus, and Escherichia coli. The results from the study displayed green synthesised AgNPs exhibit antiangiogenic activity, cytotoxicity, antimicrobial and catalytic properties, which are crucial characteristics of a molecule with excellent clinical applications.

The Chemical Composition and Antimitotic, Antioxidant, Antibacterial and Cytotoxic Properties of the Defensive Gland Extract of the Beetle, Luprops tristis Fabricius.

The unpredictable invasion of the Mupli beetle, Luprops tristis Fabricius (Coleoptera: Tenebrionidae), makes areas uninhabitable to humans. These beetles produce a strong-smelling, irritating secretion as a defence mechanism, which causes blisters on contact with human skin. In the current study, gas chromatography high-resolution mass spectrometry (GC-HRMS) analysis of the defensive gland extract of the Mupli beetle revealed the presence of compounds such as 2,3,dimethyl-1,4-benzoquinone, 1,3-dihydroxy-2-methylbenzene, 2,5-dimethyl hydroquinone, tetracosane, oleic acid, hexacosane, pentacosane, 7-hexadecenal and tert-hexadecanethiol. The defensive gland extracts showed considerable antibacterial activity on Gram-negative and Gram-positive bacteria in an agar diffusion assay. The chromosomal aberration analysis using root tips of Allium cepa L. exposed to the defensive secretion showed chromosomal aberrations such as disturbed metaphase, sticky chromosomes and chromosomal breakage. The antioxidant activity of the extract was determined using a radical scavenging (DPPH) assay. A cytotoxic assay of the defensive gland extract against Dalton's lymphoma ascites (DLA) cell line showed anticancer properties. In the present study, the defensive gland extract of the Mupli beetle, L. tristis, which is generally perceived as a nuisance insect to humans, was found to have beneficial biological activities.

Pleiotropic Hes-1 Concomitant with its Differential Activation Mediates Neural Stem Cell Maintenance and Radial Glial Propensity in Developing Neocortex.

Notch signaling pathway and its downstream effector Hes-1 are well known for their role in cortical neurogenesis. Despite the canonical activation of Hes-1 in developing neocortex, recent advances have laid considerable emphasis on Notch/CBF1-independent Hes-1 (NIHes-1) expression with poor understanding of its existence and functional significance. Here, using reporter systems and in utero electroporation, we could qualitatively unravel the existence of NIHes-1 expressing neural stem cells from the cohort of dependent progenitors throughout the mouse neocortical development. Though Hes-1 expression is maintained in neural progenitor territory at all times, a simple shift from Notch-independent to -dependent state makes it pleiotropic as the former maintains the neural stem cells in a non-dividing/slow-dividing state, whereas the latter is very much required for maintenance and proliferation of radial glial cells. Therefore, our results provide an additional complexity in neural progenitor heterogeneity regarding differential Hes-1 expression in the germinal zone during neo-cortical development.

Regulation of Tlx3 by Pax6 is required for the restricted expression of Chrnα3 in Cerebellar Granule Neuron progenitors during development.

Homeobox gene Tlx3 is known to promote glutamatergic differentiation and is expressed in post-mitotic neurons of CNS. Contrary to this here, we discovered that Tlx3 is expressed in the proliferating progenitors of the external granule layer in the cerebellum, and examined factors that regulate this expression. Using Pax6(-/-)Sey mouse model and molecular interaction studies we demonstrate Pax6 is a key activator of Tlx3 specifically in cerebellum, and induces its expression starting at embryonic day (E)15. By Postnatal day (PN)7, Tlx3 is expressed in a highly restricted manner in the cerebellar granule neurons of the posterior cerebellar lobes, where it is required for the restricted expression of nicotinic cholinergic receptor-α3 subunit (Chrnα3) and other genes involved in formation of synaptic connections and neuronal migration. These results demonstrate a novel role for Tlx3 and indicate that Pax6-Tlx3 expression and interaction is part of a region specific regulatory network in cerebellum and its deregulation during development could possibly lead to Autistic spectral disorders (ASD).

Umbilical cord blood-derived mesenchymal stem cells consist of a unique population of progenitors co-expressing mesenchymal stem cell and neuronal markers capable of instantaneous neuronal differentiation.

INTRODUCTION: Umbilical cord blood (UCB)-derived mesenchymal stem cells (MSCs) are self-renewing multipotent progenitors with the potential to differentiate into multiple lineages of mesoderm, in addition to generating ectodermal and endodermal lineages by crossing the germline barrier. In the present study we have investigated the ability of UCB-MSCs to generate neurons, since we were able to observe varying degrees of neuronal differentiation from a few batches of UCB-MSCs with very simple neuronal induction protocols whereas other batches required extensive exposure to combination of growth factors in a stepwise protocol. Our hypothesis was therefore that the human UCB-MSCs would contain multiple types of progenitors with varying neurogenic potential and that the ratio of the progenitors with high and low neurogenic potentials varies in different batches of UCB. METHODS: In total we collected 45 UCB samples, nine of which generated MSCs that were further expanded and characterized using immunofluorescence, fluorescence-activated cell sorting and RT-PCR analysis. The neuronal differentiation potential of the UCB-MSCs was analyzed with exposure to combination of growth factors. RESULTS: We could identify two different populations of progenitors within the UCB-MSCs. One population represented progenitors with innate neurogenic potential that initially express pluripotent stem cell markers such as Oct4, Nanog, Sox2, ABCG2 and neuro-ectodermal marker nestin and are capable of expanding and differentiating into neurons with exposure to simple neuronal induction conditions. The remaining population of cells, typically expressing MSC markers, requires extensive exposure to a combination of growth factors to transdifferentiate into neurons. Interesting to note was that both of these cell populations were positive for CD29 and CD105, indicating their MSC lineage, but showed prominent difference in their neurogenic potential. CONCLUSION: Our results suggest that the expanded UCB-derived MSCs harbor a small unique population of cells that express pluripotent stem cell markers along with MSC markers and possess an inherent neurogenic potential. These pluripotent progenitors later generate cells expressing neural progenitor markers and are responsible for the instantaneous neuronal differentiation; the ratio of these pluripotent marker expressing cells in a batch determines the innate neurogenic potential.

Hes-1 regulates the excitatory fate of neural progenitors through modulation of Tlx3 (HOX11L2) expression.

Tlx3 (HOX11L2) is regarded as one of the selector genes in excitatory versus inhibitory fate specification of neurons in distinct regions of the nervous system. Expression of Tlx3 in a post-mitotic immature neuron favors a glutamatergic over GABAergic fate. The factors that regulate Tlx3 have immense importance in the fate specification of glutamatergic neurons. Here, we have shown that Notch target gene, Hes-1, negatively regulates Tlx3 expression, resulting in decreased generation of glutamatergic neurons. Down-regulation of Hes-1 removed the inhibition on Tlx3 promoter, thus promoting glutamatergic differentiation. Promoter-protein interaction studies with truncated/mutated Hes-1 protein suggested that the co-repressor recruitment mediated through WRPW domain of Hes-1 has contributed to the repressive effect. Our results clearly demonstrate a new and unique role for canonical Notch signaling through Hes-1, in neurotransmitter/subtype fate specification of neurons in addition to its known functional role in proliferation/maintenance of neural progenitors.