ES5 is involved in the regulation of phosphatidylserine synthesis and impacts on early senescence in rice (Oryza sativa L.)

Leaf senescence, which affects plant growth and yield in rice, is an ideal target for crop improvement and remarkable advances have been made to identify the mechanism underlying this process. We have characterized an early senile mutant es5 (early leaf senescence 5) in rice exhibiting leaf yellowing phenotype after the 4-leaf stage. This phenotype was confirmed by the higher accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA), the disintegration of chloroplasts, reduction in chlorophyll content and photosynthetic rate and up-regulation of senescence-associated genes (SAGs) like Osh36, OsI57, and OsI85. Positional cloning revealed that the es5 phenotype is the result of one base substitution in ES5, encoding phosphatidylserine synthase (PSS) family protein, which is involved in the base-exchange type reaction to synthesize the minor membrane phospholipid phosphatidylserine. Functional complementation of ES5 in the es5 plants completely restored the wild-type phenotype. Ultra-high-performance liquid chromatography (UHPLC) analysis showed that es5 plants had increased levels of phosphatidylserine (PS) and decreased level of phosphatidylcholine (PC). These results provide evidence about the role of PS in rice leaf senescence.

     

CCAAT/enhancer-binding protein beta (C/EBPβ) knockdown reduces inflammation,ER stress,and apoptosis,and promotes autophagy in oxLDL-treated RAW264.7 macrophage cells

Molecular and Cellular Biochemistry - Atherosclerosis is associated with deregulated cholesterol metabolism and formation of macrophage foam cells. CCAAT/enhancer-binding protein beta (C/EBPβ)...     

Potential evolutionary trade-off between feeding and stability in Cambrian cinctan echinoderms

Reconstructing the function and behaviour of extinct groups of echinoderms is problematic because there are no modern analogues for their aberrant body plans. Cinctans, an enigmatic group of Cambrian echinoderms, exemplify this problem: their asymmetrical body plan differentiates them from all living species. Here, we used computational fluid dynamics to analyse the functional performance of cinctans without assuming an extant comparative model. Three-dimensional models of six species from across cinctan phylogeny were used in computer simulations of water flow. The results demonstrate that cinctans with strongly flattened bodies produced much less drag than species characterized by dorsal protuberances or swellings, suggesting the former were more stable on the seafloor. However, unlike the flattened forms, cinctans with high-relief bodies were able to passively direct flow towards the mouth and associated food grooves, indicating that they were capable of more efficient feeding on particles suspended in the water. This study provides evidence of a previously unknown evolutionary trade-off between feeding and stability in Cambrian cinctan echinoderms.     

Treatment of nitric oxide supplemented with nitrogen and sulfur regulates photosynthetic performance and stomatal behavior in mustard under salt stress

Nitric oxide (NO) is a hormone that connects numerous reactions in plant cells under normal and environmental stress conditions. The application of 100 µM NO as sodium nitroprusside (SNP; NO donor) applied individually or in combination with N or S in different combinations (i.e. 100 mg N or S kg⁻¹ soil applied at the time of sowing [100 N + 100S]_0d or with split, 50 mg N or S kg⁻¹ soil at the time of sowing and similar dose at 20 d after sowing [50 N + 50S]_0d + [50 N + 50S]_20d) was tested to alleviate salt stress in mustard (Brassica juncea L.). Application of 100 µM NO plus split application of N and S more significantly promoted stomatal behavior, photosynthetic and growth performance in the absence of salt stress and maximally alleviated effects of salt stress through increased N- and S-use efficiency, proline and antioxidant system. The combined application of N and S at the time of sowing was lesser effective in promoting photosynthesis and growth under salt or no salt stress conditions in presence or absence of NO. The study suggests that salt stress effects on the photosynthetic performance are mitigated more efficiently when NO was applied together with the split application of N and S given at two stages, and the photosynthetic activity was promoted under salt stress through increased N and S assimilation and antioxidant system. This strategy may be adopted in agricultural system for overcoming salt stress effects on performance of mustard.     

Development of EST-SSR markers for genetic diversity analysis in coconut (Cocos nucifera L.)

Molecular Biology Reports - Genetic improvement in coconut relies on exploiting the vast existing diversity among coconut accessions. Robust molecular markers are a pre-requisite for efficient...     

Biophysical insights into the binding characteristics of bovine serum albumin with dipyridamole and the influence of molecular interaction with β cyclodextrin

Abstract

The binding characteristic of anti-platelet drug dipyridamole has been investigated with a transport protein, serum albumin. A multi-spectroscopic approach has been employed, and the results were well supported by in silico molecular docking and simulation studies. The fluorescence quenching of serum albumin at three different temperatures revealed that the mechanism involved is static and the binding constant of the interaction was found to be of the order of 10⁴ M^?1. The reaction was found to be spontaneous and involved hydrophobic interactions. Synchronous, 3D fluorescence and CD spectroscopy indicated a change in conformation of bovine serum albumin (BSA) on interaction with DP. Using site-selective markers, the binding site of DP was found to be in subdomain IB. Molecular docking studies further corroborated these results. Molecular dynamic (MD) simulations showed lower RMSD values on interaction, suggesting the existence of a stable complex between DP and BSA. Furthermore, since β-Cyclodextrin (βCD) is used to improve the solubility of DP in ophthalmic solutions, therefore, the effect of (βCD) on the interaction of BSA and DP was also studied, and it was found that in the presence of βCD, the binding constant for BSA-DP interaction decreased. The present study is an attempt to characterize the transport of DP and to improve its bioavailability, consequently helping in dosage design to achieve optimum therapeutic levels.

Communicated by Ramaswamy H. Sarma     

Reduction of nuclear Y654-p-β-catenin expression through SH3GL2-meditated downregulation of EGFR in chemotolerance TNBC: Clinical and prognostic importance

Triple negative breast cancer (TNBC) originates from a less differentiated ductal cell of breast, which is less sensitive to chemotherapy. The chemotolerance mechanism of TNBC has not yet been studied in detail. For this reason, molecular profiles (expression/genetic/epigenetic) of Y654-p-β-catenin (active) and its kinase epidermal growth factor receptor (EGFR) along with SH3GL2 (regulator of EGFR homeostasis) were compared between neoadjuvant chemotherapy treated (NACT) and pretherapeutic TNBC samples. Reduced nuclear expression of Y654-p-β-catenin protein with low proliferation index and CD44 prevalence showed concordance with reduced expression of EGFR/Y1045-p-EGFR proteins in the NACT samples than the pretherapeutic TNBC samples. Infrequent messenger RNA expression, gene amplification (10–32.5%), and mutation (1%) of EGFR were seen in the TNBC samples irrespective of therapy, suggesting the importance of EGFR protein stabilization in this tumor. The upregulation of SH3GL2 seen in the NACT samples in contrast to the pretherapeutic samples might be due to its promoter hypomethylation, as seen in the quantitative methylation assay. A similar trend of upregulation of SH3GL2 and downregulation of EGFR, Y1045-p-EGFR, Y654-p-β-catenin were seen in the MDA-MB-231 cell line using antharacycline antitumor drugs (doxorubicin/nogalamycin). The NACT patients with reduced expression of Y654-p-β-catenin and/or EGFR and high expression of SH3GL2 showed comparatively better prognosis than the pretherapeutic patients. Thus, our study showed that reduced nuclear expression of Y654-p-β-catenin in NACT samples due to downregulation of EGFR protein through promoter hypomethylation-mediated upregulation of SH3GL2, resulting in low proliferation index/CD44 prevalence with better prognosis of the NACT patients, might have an important role in the chemotolerance of TNBC.     

A critical look on CRISPR-based genome editing in plants

Clustered regularly interspaced short palindromic repeats (CRISPR)-based genome editing, derived from prokaryotic immunity system, is rapidly emerging as an alternative platform for introducing targeted alterations in genomes. The CRISPR-based tools have been deployed for several other applications including gene expression studies, detection of mutation patterns in genomes, epigenetic regulation, chromatin imaging, etc. Unlike the traditional genetic engineering approaches, it is simple, cost-effective, and highly specific in inducing genetic variations. Despite its popularity, the technology has limitations such as off-targets, low mutagenesis efficiency, and its dependency on in-vitro regeneration protocols for the recovery of stable plant lines. Several other issues such as persisted CRISPR activity in subsequent generations, the potential for transferring to its wild type population, the risk of reversion of edited version to its original phenotype particularly in cross-pollinated plant species when released into the environment and the scarcity of validated targets have been overlooked. This article briefly highlights these undermined aspects, which may challenge the wider applications of this platform for improving crop genetics.     

Polymorphism in the internal transcribed spacer (ITS) region of the ribosomal DNA among different Fusarium species

Fusarium species causing wilt diseases in different plants were characterised by comparing nonpathogenic and different pathogenic species using rDNA RFLP analysis. The ITS (internal transcribed spacer) region of 12 isolates belonging to the section Elegans, Laseola, Mortiella, Discolor, Gibbosum, Lateritium and Sporotrichiella were amplified by universal ITS primers (ITS-1 and ITS-4) using polymerase chain reaction (PCR). Amplified products, which ranged from 522 to 565 bp were obtained from all 12 Fusarium isolates. The amplified products were digested with seven restriction enzymes, and restriction fragment length polymorphism (RFLP) patterns were analysed. A dendrogram derived from PCR-RFLP analysis of the rDNA region divided the Fusarium isolates into three major groups. Assessment of molecular variability based on rDNA RFLP clearly indicated that Fusarium species are heterogeneous and most of the forma speciales have close evolutionary relationships.