Asymbiotic seed germination of Cymbidium bicolor Lindl. (Orchidaceae) and the influence of mycorrhizal fungus on seedling development

An in vitro plant regeneration protocol was successfully established for Cymbidium bicolor an epiphytic orchid by culturing seeds from green pods. Immature seeds were germinated on four basal media viz., Murashige and Skoog (MS) medium, Knudson C (KC) orchid medium, Knudson C modified Morel (KCM) medium and Lindemann orchid (LO) medium. Seed germination and protocorm development was significantly higher in LO medium (96.6 %) followed by KCM (89 %), MS (77.5 %) and KC (62.7 %) media after 56 days. For multiple shoot induction the protocorms were transferred to B5 medium supplemented with cytokinin. Among the various cytokinins tested, BAP (4.42 μM) induced maximum (27.59) number of multiple shoots per explant. IBA was effective in inducing healthy roots. Tissue-cultured protocorms and seedlings of C. bicolor were inoculated with AC-01 fungal strain (Moniliopsis sp.) isolated from the mycorrizal roots of an epiphytic orchid Aerides crispum. Mycorrhizal fungi significantly enhanced number of roots, root length and shoot number.     

The translocator protein ligands as mitochondrial functional modulators for the potential anti-Alzheimer agents

Small molecule modulators of mitochondrial function have been attracted much attention in recent years due to their potential therapeutic applications for neurodegenerative diseases. The mitochondrial translocator protein (TSPO) is a promising target for such compounds, given its involvement in the formation of the mitochondrial permeability transition pore in response to mitochondrial stress. In this study, we performed a ligand-based pharmacophore design and virtual screening, and identified a potent hit compound, 7 (VH34) as a TSPO ligand. After validating its biological activity against amyloid-β (Aβ) induced mitochondrial dysfunction and in acute and transgenic Alzheimer’s disease (AD) model mice, we developed a library of analogs, and we found two most active compounds, 31 and 44, which restored the mitochondrial membrane potential, ATP production, and cell viability under Aβ-induced mitochondrial toxicity. These compounds recovered learning and memory function in acute AD model mice with improved pharmacokinetic properties.     

TBC1D13 is a RAB35 Specific GAP that Plays an Important Role in GLUT4 Trafficking in Adipocytes

Insulin stimulates glucose transport in adipocytes by triggering translocation of GLUT4 glucose transporters to the plasma membrane (PM) and several Rabs including Rab10 have been implicated in this process. To delineate the molecular regulation of this pathway, we conducted a TBC/RabGAP overexpression screen in adipocytes. This identified TBC1D13 as a potent inhibitor of insulin-stimulated GLUT4 translocation without affecting other trafficking pathways. To determine the potential Rab substrate for TBC1D13 we conducted a yeast two-hybrid screen and found that the GTP bound forms of Rabs 1 and 10 specifically interacted with TBC1D13 but not with eight other TBC proteins. Surprisingly, a comprehensive in vitro screen for TBC1D13 GAP activity revealed Rab35 but not Rab10 as a specific substrate. TBC1D13 also displayed in vivo GAP activity towards Rab35. Overexpression of constitutively active Rab35 but not constitutively active Rab10 reversed the block in insulin-stimulated GLUT4 translocation observed with TBC1D13 overexpression. These studies implicate an important role for Rab35 in insulin-stimulated GLUT4 translocation in adipocytes.     

Pyroglutamate stimulates Na+ -dependent glutamate transport across the blood-brain barrier

Regulation of Na(+)-dependent glutamate transport was studied in isolated luminal and abluminal plasma membranes derived from the bovine blood-brain barrier. Abluminal membranes have Na(+)-dependent glutamate transporters while luminal membranes have facilitative transporters. This organization allows glutamate to be actively removed from brain. gamma-Glutamyl transpeptidase, the first enzyme of the gamma-glutamyl cycle (GGC), is on the luminal membrane. Pyroglutamate (oxoproline), an intracellular product of GGC, stimulated Na(+)-dependent transport of glutamate by 46%, whereas facilitative glutamate uptake in luminal membranes was inhibited. This relationship between GGC and glutamate transporters may be part of a regulatory mechanism that accelerates glutamate removal from brain.     

Insights from the molecular docking aided interaction analysis of HfQ with small RNAs

Hfq, RNA binding protein, is widely found in most of the prokaryotes. It plays a key role in gene regulation by binding with small RNA and facilitates mRNA pairing there by suppress or boost translation according to RNA structures. Interaction between sRNAs and HfQ in Salmonella SL1344 were screened using Co-Immuno Precipitation (HfQ-CoIP) studies earlier. We have formulated an In silico approach, to model the 3D structures of 155 sRNA and studied their interactions with HfQ proteins. We have reported the key interacting PHE42, LEU7, VAL27, PHE39 and PRO21 residues of HfQ binds with many small RNAs. Further mutation of PHE42 in to ALA42 in HfQ leads to loss of sRNA binding efficiency. We have differentiated the interactions in to HfQ binding and non-binding sRNAs, based on Atomic Contact Energy and area. This methodology may be applied generically for functional grouping of small RNAs in any organism.     

RoBuST: an integrated genomics resource for the root and bulb crop families Apiaceae and Alliaceae

Background  

Root and bulb vegetables (RBV) include carrots, celeriac (root celery), parsnips (Apiaceae), onions, garlic, and leek (Alliaceae)—food crops grown globally and consumed worldwide. Few data analysis platforms are currently available where data collection, annotation and integration initiatives are focused on RBV plant groups. Scientists working on RBV include breeders, geneticists, taxonomists, plant pathologists, and plant physiologists who use genomic data for a wide range of activities including the development of molecular genetic maps, delineation of taxonomic relationships, and investigation of molecular aspects of gene expression in biochemical pathways and disease responses. With genomic data coming from such diverse areas of plant science, availability of a community resource focused on these RBV data types would be of great interest to this scientific community.     

Reduced Crossover Interference and Increased ZMM-Independent Recombination in the Absence of Tel1/ATM

Meiotic recombination involves the repair of double-strand break (DSB) precursors as crossovers (COs) or noncrossovers (NCOs). The proper number and distribution of COs is critical for successful chromosome segregation and formation of viable gametes. In budding yeast the majority of COs occurs through a pathway dependent on the ZMM proteins (Zip2-Zip3-Zip4-Spo16, Msh4-Msh5, Mer3), which form foci at CO-committed sites. Here we show that the DNA-damage-response kinase Tel1/ATM limits ZMM-independent recombination. By whole-genome mapping of recombination products, we find that lack of Tel1 results in higher recombination and reduced CO interference. Yet the number of Zip3 foci in tel1Δ cells is similar to wild type, and these foci show normal interference. Analysis of recombination in a tel1Δ zip3Δ double mutant indicates that COs are less dependent on Zip3 in the absence of Tel1. Together these results reveal that in the absence of Tel1, a significant proportion of COs occurs through a non-ZMM-dependent pathway, contributing to a CO landscape with poor interference. We also see a significant change in the distribution of all detectable recombination products in the absence of Tel1, Sgs1, Zip3, or Msh4, providing evidence for altered DSB distribution. These results support the previous finding that DSB interference depends on Tel1, and further suggest an additional level of DSB interference created through local repression of DSBs around CO-designated sites.