43 research outputs found
Stereoselective synthesis of C1-C11 fragment of antitumor cyclodepsipeptide (–)-doliculide
376-384A general and stereoselective synthetic route for C1-C11 polyketide fragment of doliculide has been achieved in an efficient manner. The key reactions of our synthetic route are enzymatic desymmetrization of meso-diol, application of Evans auxiliary to introduce methyl group, Sharpless asymmetric epoxidation and substrate controlled nucleophilic addition reactions
Quantitative Immunohistochemistry to Measure Regional Expression of Nurr1 in the Brain and the Effect of the Nurr1 Heterozygous Genotype
Genome-wide identification and expression profile analysis of nuclear factor Y family genes in Sorghum bicolor L. (Moench)
Members of the plant Heme Activator Protein (HAP) or NUCLEAR FACTOR Y (NF-Y) are trimeric
transcription factor complexes composed of the NF-YA, NF-YB and NF-YC subfamilies.
They bind to the CCAAT box in the promoter regions of the target genes and regulate gene
expressions. Plant NF-Ys were reported to be involved in adaptation to several abiotic
stresses as well as in development. In silico analysis of Sorghum bicolor genome resulted in
the identification of a total of 42 NF-Y genes, among which 8 code for the SbNF-YA, 19 for
SbNF-YB and 15 for the SbNF-YC subunits. Analysis was also performed to characterize
gene structures, chromosomal distribution, duplication status, protein subcellular localizations,
conserved motifs, ancestral protein sequences, miRNAs and phylogenetic tree construction.
Phylogenetic relationships and ortholog predictions displayed that sorghum has additional
NF-YB genes with unknown functions in comparison with Arabidopsis. Analysis of promoters
revealed that they harbour many stress-related cis-elements like ABRE and HSE, but surprisingly,
DRE and MYB elements were not detected in any of the subfamilies. SbNF-YA1, 2, and
6 were found upregulated under 200 mM salt and 200 mM mannitol stresses. While NF-YA7
appeared associated with high temperature (40˚C) stress, NF-YA8 was triggered by both cold
(4˚C) and high temperature stresses. Among NF-YB genes, 7, 12, 15, and 16 were induced
under multiple stress conditions such as salt, mannitol, ABA, cold and high temperatures.
Likewise, NF-YC 6, 11, 12, 14, and 15 were enhanced significantly in a tissue specific manner
under multiple abiotic stress conditions. Majority of the mannitol (drought)-inducible genes
were also induced by salt, high temperature stresses and ABA. Few of the high temperature
stress-induced genes are also induced by cold stress (NF-YA2, 4, 6, 8, NF-YB2, 7, 10, 11, 12,
14, 16, 17, NF-YC4, 6, 12, and 13) thus suggesting a cross talk among them. This work paves
the way for investigating the roles of diverse sorghum NF-Y proteins during abiotic stress
responses and provides an insight into the evolution of diverse NF-Y members
Root and Leaf Anatomy, Ion Accumulation, and Transcriptome Pattern under Salt Stress Conditions in Contrasting Genotypes of Sorghum bicolor
Roots from salt-susceptible ICSR-56 (SS) sorghum plants display metaxylem elements with thin cell walls and large diameter. On the other hand, roots with thick, lignified cell walls in the hypodermis and endodermis were noticed in salt-tolerant CSV-15 (ST) sorghum plants. The secondary wall thickness and number of lignified cells in the hypodermis have increased with the treatment of sodium chloride stress to the plants (STN). Lignin distribution in the secondary cell wall of sclerenchymatous cells beneath the lower epidermis was higher in ST leaves compared to the SS genotype. Casparian thickenings with homogenous lignin distribution were observed in STN roots, but inhomogeneous distribution was evident in SS seedlings treated with sodium chloride (SSN). Higher accumulation of K+ and lower Na+ levels were noticed in ST compared to the SS genotype. To identify the differentially expressed genes among SS and ST genotypes, transcriptomic analysis was carried out. Both the genotypes were exposed to 200 mM sodium chloride stress for
24 h and used for analysis. We obtained 70 and 162 differentially expressed genes (DEGs) exclusive to SS and SSN and 112 and 26 DEGs exclusive to ST and STN, respectively. Kyoto Encyclopaedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analysis unlocked the changes in metabolic pathways in response to salt stress. qRT-PCR was performed to validate 20 DEGs in
each SSN and STN sample, which confirms the transcriptomic results. These results surmise that anatomical changes and higher K+/Na+ ratios are essential for mitigating salt stress in sorghum apart from the genes that are differentially up- and downregulated in contrasting genotypes
An update and perspectives on the use of promoters in plant genetic engineering
Genetically engineered plants have varied applications in agriculture for enhancing the values of food and feed.
Genetic engineering aims to introduce selected genetic regions with desirable traits into target plants for both
spatial and temporal expressions. Promoters are the key elements responsible for regulating gene expressions
by modulating the transcription factors (TFs) through recognition of RNA polymerases. Based on their
recognition and expression, RNA polymerases were categorized into RNA pol II and pol III promoters.
Promoter activity and specificity are the two prime parameters in regulating the transgene expression. Since the
use of constitutive promoters like Cauliflower mosaic virus (CaMV) 35S may lead to adverse effects on nontarget
organisms or ecosystem, inducible/tissue specific promoters and/or the RNA pol III promoters provide
myriad opportunities for gene expressions with controlled regulation and with minimum adverse effects.
Besides their role in transgene expression, their influence in synthetic biology and genome editing are also
discussed. This review provides an update on the importance, current prospects, and insight into the advantages
and disadvantages of promoters reported thus far would help to utilize them in the endeavour to develop
nutritionally and agronomically improved transgenic crops for commercialization
Antifungal benzo[b]thiophene 1,1-dioxide IMPDH inhibitors exhibit pan-assay interference (PAINS) profiles
Fungi cause serious life-threatening infections in immunocompromised individuals and current treatments are now complicated by toxicity issues and the emergence of drug resistant strains. Consequently, there is a need for development of new antifungal drugs. Inosine monophosphate dehydrogenase (IMPDH), a key component of the de novo purine biosynthetic pathway, is essential for growth and virulence of fungi and is a potential drug target. In this study, a high-throughput screen of 114,000 drug-like compounds against Cryptococcus neoformans IMPDH was performed. We identified three 3-((5-substituted)-1,3,4-oxadiazol-2-yl)thio benzo[b]thiophene 1,1-dioxides that inhibited Cryptococcus IMPDH and also possessed whole cell antifungal activity. Analogs were synthesized to explore the SAR of these hits. Modification of the fifth substituent on the 1,3,4-oxadiazole ring yielded compounds with nanomolar in vitro activity, but with associated cytotoxicity. In contrast, two analogs generated by substituting the 1,3,4-oxadiazole ring with imidazole and 1,2,4-triazole gave reduced IMPDH inhibition in vitro, but were not cytotoxic. During enzyme kinetic studies in the presence of DTT, nucleophilic attack of a free thiol occurred with the benzo[b]thiophene 1,1-dioxide. Two representative compounds with substitution at the 5 position of the 1,3,4-oxadiazole ring, showed mixed inhibition in the absence of DTT. Incubation of these compounds with Cryptococcus IMPDH followed by mass spectrometry analysis showed non-specific and covalent binding with IMPDH at multiple cysteine residues. These results support recent reports that the benzo[b]thiophene 1,1-dioxides moiety as PAINS (pan-assay interference compounds) contributor
Coupled piezoelectric fans with two degree of freedom motion for the application of flapping wing micro aerial vehicles
Piezoelectric fans consisting of a piezoelectric layer and an elastic metal
layer were prepared by epoxy bonding and a coupled flexible wing was formed by a
pair of carbon fibre reinforced plastic wing spars and polymer skin attached to
two piezoelectric fans. Two sinusoidal voltages with phase differences were then
used to drive the coupled piezoelectric fans. High speed digital cameras were
used to characterize the two degree of freedom (DOF) motion of the wing and
these results were compared to finite element model of the wing and the coupled
piezoelectric fans. It has been observed that the phase delay between the
driving voltages applied to the coupled piezoelectric fans plays an important
role in the control of the flapping and twisting motions of the wing and this
set-up has the potential for application to the control of flapping wings for
micro aerial vehicles. (c) 2008 Elsevier B.V. All rights reserved
Template-cum-catalysis free synthesis of α-MnO2 nanorods-hierarchical MoS2 microspheres composite for ultra-sensitive and selective determination of nitrite
In this work, a novel composite constituted by α-MnO2 nanorods and hierarchical MoS2 microspheres is synthesized by a simple, template-cum-catalysis free two-step hydrothermal method for ultra-sensitive and selective detection of nitrite. The nitrite sensor (with optimal MnO2-MoS2 weight ratio) showed a limit of detection of 16 μM, the short response time (<5 s), outstanding selectivity, reproducibility, and sensitivity of 515.84 μA mM−1 cm−2 (R2 = 0.996) in the range of 100–800 μM in an optimized electrolytic pH of 4. The excellent sensing ability of the sensor can be attributed to the heterogeneous interface between two material constituents that results in unimpeded electrical transport due to the presence of intertwined nanosheets in MoS2 and 1D α-MnO2 nanorods, high number of active sites emanating from huge numbers of edges and defects in MoS2, high proportion of metallic (1T) phase than semiconducting (2H) phase in MoS2 and the combined effect of 1D α-MnO2 nanorods and MoS2 nanosheets. The fabricated sensor was also effectively assessed for the detection of nitrite in potable water. This novel, binder-free, MnO2-MoS2 composite based electrode material paves a new way for the development of simple, non-enzymatic and inexpensive electrochemical sensors for analytical applications