Optimized in vitro micro-tuber production for colchicine biosynthesis in Gloriosa superba L. and its anti-microbial activity against Candida albicans

Plant Cell, Tissue and Organ Culture (PCTOC) - Gloriosa superba L. tubers are a rich source of commercially important colchicine and due to overexploitation, the species has become vulnerable. In...     

BLOC-2 targets recycling endosomal tubules to melanosomes for cargo delivery

Hermansky–Pudlak syndrome (HPS) is a group of disorders characterized by the malformation of lysosome-related organelles, such as pigment cell melanosomes. Three of nine characterized HPS subtypes result from mutations in subunits of BLOC-2, a protein complex with no known molecular function. In this paper, we exploit melanocytes from mouse HPS models to place BLOC-2 within a cargo transport pathway from recycling endosomal domains to maturing melanosomes. In BLOC-2–deficient melanocytes, the melanosomal protein TYRP1 was largely depleted from pigment granules and underwent accelerated recycling from endosomes to the plasma membrane and to the Golgi. By live-cell imaging, recycling endosomal tubules of wild-type melanocytes made frequent and prolonged contacts with maturing melanosomes; in contrast, tubules from BLOC-2–deficient cells were shorter in length and made fewer, more transient contacts with melanosomes. These results support a model in which BLOC-2 functions to direct recycling endosomal tubular transport intermediates to maturing melanosomes and thereby promote cargo delivery and optimal pigmentation.     

Epidermal Growth Factor Activates the Rho GTPase-activating Protein (GAP) Deleted in Liver Cancer 1 via Focal Adhesion Kinase and Protein Phosphatase 2A

Deleted in Liver Cancer 1 (DLC1) is a RHO GTPase-activating protein (GAP) that negatively regulates RHO. Through its GAP activity, it modulates the actin cytoskeleton network and focal adhesion dynamics, ultimately leading to suppression of cell invasion and metastasis. Despite its presence in various structural and signaling components, little is known about how the activity of DLC1 is regulated at focal adhesions. Here we show that EGF stimulation activates the GAP activity of DLC1 through a concerted mechanism involving DLC1 phosphorylation by MEK/ERK and its subsequent dephosphorylation by protein phosphatase 2A (PP2A) and inhibition of focal adhesion kinase by MEK/ERK to allow the binding between DLC1 and PP2A. Phosphoproteomics and mutation studies revealed that threonine 301 and serine 308 on DLC1, known previously to be mutated in certain cancers, are required for DLC1-PP2A interaction and the subsequent activation of DLC1 upon their dephosphorylation. The intricate interplay of this “MEK/ERK-focal adhesion kinase-DLC1-PP2A” quartet provides a novel checkpoint in the spatiotemporal control of cell spreading and cell motility.     

Gelsemiaceae (Gentianales) expanded to include the enigmatic Asian genus Pteleocarpa

The enigmatic South‐East Asian monotypic genus Pteleocarpa has been considered as a genus incertae sedis among the eudicots for a long time. Molecular data (plastid and nuclear ribosomal regions) from 44 widely sampled species across Lamiidae and phylogenetic analyses have finally clarified its familial relationships, and it is here included in Gelsemiaceae (order Gentianales). Its morphological characteristics support a placement in this family and order as a result of the presence of potential synapomorphies, such as imbricate and commonly yellow corollas, latrorse anther dehiscence, divided styles and compressed seeds. Unique characters for Pteleocarpa in Gelsemiaceae are alternate leaves and indehiscent samaras. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 175 , 482–496.     

Bacillus mesophilum sp. nov., strain IITR-54T,a novel 4-chlorobiphenyl dechlorinating bacterium

The taxonomic position of a Gram-positive, endospore-forming bacterium isolated from soil sample collected from an industrial site was analyzed by a polyphasic approach. The strain designated as IITR-54^T matched most of the phenotypic and chemical characteristics of the genus Bacillus and represents a novel species. It was found to biodegrade 4-chlorobiphenyl through dechlorination and was isolated through enrichment procedure from an aged polychlorinated biphenyl-contaminated soil. Both resting cell assay and growth under aerobic liquid conditions using 4-chlorobiphenyl as sole source of carbon along with 0.01 % yeast extract, formation of chloride ions was measured. 16S rRNA (1,489 bases) nucleotide sequence of isolated strain was compared with those of closely related Bacillus type strains and confirmed that the strain belongs to the genus Bacillus. Strain IITR-54^T differs from all other species of Bacillus by at least 2.1 % at the 16S rRNA level, and the moderately related species are Bacillus oceanisediminis (97.9 %) followed by Bacillus infantis (97.7 %), Bacillus firmus (97.4 %), Bacillus drentensis (97.3 %), Bacillus circulans (97.2 %), Bacillus soli (97.1 %), Bacillus horneckiae (97.1 %), Bacillus pocheonensis (97.1 %) and Bacillus bataviensis (97.1 %), respectively. The cell wall peptidoglycan contained meso-diaminopimelic acid and the major isoprenoid quinone was MK-7. Major fatty acids are iso-C_15:0 (32.4 %) and anteiso-C_15:0 (27.4 %). Predominant polar lipids are diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The results of physiological and biochemical tests allowed the genotypic and phenotypic distinctiveness of strain IITR-54^T with its phylogenetic relatives and suggest that the strain IITR-54^T should be recognized as a novel species, for which the name Bacillus mesophilum sp. nov. is proposed. The type strain is IITR-54^T (= MTCC 11060^T = JCM 19208^T).     

Poly-lysine peptidomimetics having potent antimicrobial activity without hemolytic activity

Diversity of sequence and structure in naturally occurring antimicrobial peptides (AMPs) limits their intensive structure–activity relationship (SAR) study. In contrast, peptidomimetics have several advantages compared to naturally occurring peptide in terms of simple structure, convenient to analog synthesis, rapid elucidation of optimal physiochemical properties and low-cost synthesis. In search of short antimicrobial peptides using peptidomimetics, which provide facile access to identify the key factors involving in the destruction of pathogens through SAR study, a series of simple and short peptidomimetics consisting of multi-Lys residues and lipophilic moiety have been prepared and found to be active against several Gram-negative and Gram-positive bacteria containing methicillin-resistant Staphylococcus aureus (MRSA) without hemolytic activity. Based on the SAR studies, we found that hydrophobicity, +5 charges of multiple Lys residues, hydrocarbon tail lengths and cyclohexyl group were crucial for antimicrobial activity. Furthermore, membrane depolarization, dye leakage, inner membrane permeability and time-killing kinetics revealed that bacterial-killing mechanism of our peptidomimetics is different from the membrane-targeting AMPs (e. g. melittin and SMAP-29) and implied our peptidomimetics might kill bacteria via the intracellular-targeting mechanism as done by buforin-2.     

PPS: A computing engine to find Palindromes in all Protein sequences

The primary structure of a protein molecule comprises a linear chain of amino acid residues. Certain parts of this linear chain are unique in nature and function. They can be classified under different categories and their roles studied in detail. Two such unique categories are the palindromic sequences and the Single Amino Acid Repeats (SAARs), which plays a major role in the structure, function and evolution of the protein molecule. In spite of their presence in various protein sequences, palindromes have not yet been investigated in detail. Thus, to enable a comprehensive understanding of these sequences, a computing engine, PPS, has been developed. The users can search the occurrences of palindromes and SAARs in all the protein sequences available in various databases and can view the three-dimensional structures (in case it is available in the known three-dimensional protein structures deposited to the Protein Data Bank) using the graphics plug-in Jmol. The proposed server is the first of its kind and can be freely accessed through the World Wide Web.

Availability

URL http://pranag.physics.iisc.ernet.in/pps/     

Tetrahydroquinazole-based secondary sulphonamides as carbonic anhydrase inhibitors: synthesis,biological evaluation against isoforms I,II, IV,and IX,and computational studies

A library of variously decorated N-phenyl secondary sulphonamides featuring the bicyclic tetrahydroquinazole scaffold was synthesised and biologically evaluated for their inhibitory activity against human carbonic anhydrase (hCA) I, II, IV, and IX. Of note, several compounds were identified showing submicromolar potency and excellent selectivity for the tumour-related hCA IX isoform. Structure–activity relationship data attained for various substitutions were rationalised by molecular modelling studies in terms of both inhibitory activity and selectivity.     

Aldose reductase modulates cardiac glycogen synthase kinase-3β phosphorylation during ischemia-reperfusion

Earlier studies have demonstrated that aldose reductase (AR) plays a key role in mediating ischemia-reperfusion (I/R) injury. Our objective was to investigate if AR mediates I/R injury by influencing phosphorylation of glycogen synthase kinase-3β (p-GSK3β). To investigate this issue, we used three separate models to study the effects of stress injury on the heart. Hearts isolated from wild-type (WT), human expressing AR transgenic (ARTg), and AR knockout (ARKO) mice were perfused with/without GSK3β inhibitors (SB-216763 and LiCl) and subjected to I/R. Ad-human AR (Ad-hAR)-expressing HL-1 cardiac cells were exposed to hypoxia (0.5% O(2)) and reoxygenation (20.9% O(2)) conditions. I/R in a murine model of transient occlusion and reperfusion of the left anterior descending coronary artery (LAD) was used to study if p-GSK3β was affected through increased AR flux. Lactate dehydrogenase (LDH) release and left ventricular developed pressure (LVDP) were measured. LVDP was decreased in hearts from ARTg mice compared with WT and ARKO after I/R, whereas LDH release and apoptotic markers were increased (P < 0.05). p-GSK3β was decreased in ARTg hearts compared with WT and ARKO (P < 0.05). In ARKO, p-GSK3β and apoptotic markers were decreased compared with WT (P < 0.05). WT and ARTg hearts perfused with GSK3β inhibitors improved p-GSK3β expression and LVDP and exhibited decreased LDH release, apoptosis, and mitochondrial pore opening (P < 0.05). Ad-hAR-expressing HL-1 cardiac cells, exposed to hypoxia (0.5% O(2)) and reoxygenation (20.9% O(2)), had greater LDH release compared with control HL-1 cells (P < 0.05). p-GSK3β was decreased and correlated with increased apoptotic markers in Ad-hAR HL-1 cells (P < 0.05). Treatment with phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) inhibitor increased injury demonstrated by increased LDH release in ARTg, WT, and ARKO hearts and in Ad-hAR-expressing HL-1 cells. Cells treated with protein kinase C (PKC) α/β inhibitor displayed significant increases in p-Akt and p-GSK3β expression, and resulted in decreased LDH release. In summary, AR mediates changes in p-GSK3β, in part, via PKCα/β and Akt during I/R.     

Chemical composition and antioxidant activity of Strobilanthes crispus leaf extract

This study investigated the components present in and the total antioxidant activity of leaves of Strobilanthes crispus (L.) Bremek or Saricocalyx crispus (L.) Bremek (Acanthacea). Proximate analyses and total antioxidant activity using ferric thiocyanate and thiobarbituric acid methods were employed. Minerals content was determined using the atomic absorption spectrophotometer, whereas the water-soluble vitamins were determined by means of the UV-VIS spectrophotometer (vitamin C) and fluorimeter (vitamins B₁ and B₂). Catechin, tannin, caffeine, and alkaloid contents were also studied. All data were compared to the previously reported results of Yerbamate, green tea, black tea, and Indian tea. The dried leaves contained a high amount of total ash (21.6%) as a result of a high amount of minerals including potassium (51%), calcium (24%), sodium (13%), iron (1%), and phosphorus (1%). High content of water-soluble vitamins (C, B₁, and B₂) contributed to the high antioxidant activity of the leaves. The leaves also contained a moderate amount of other proximate composition as well as other compounds such as catechins, alkaloids, caffeine, and tannin, contributing further to the total antioxidant activity. Catechins of Strobilanthes crispus leaves showed highest antioxidant activity when compared to Yerbamate and vitamin E. Consumption of the leafy extract daily (5 g/day) as an herbal tea could contribute to the additional nutrients and antioxidants needed in the body to enhance the defense system, especially toward the incidence of degenerative diseases.