Arabidopsis thaliana ASN2 encoding asparagine synthetase is involved in the control of nitrogen assimilation and export during vegetative growth

We investigated the function of ASN2, one of the three genes encoding asparagine synthetase (EC 6.3.5.4), which is the most highly expressed in vegetative leaves of Arabidopsis thaliana. Expression of ASN2 and parallel higher asparagine content in darkness suggest that leaf metabolism involves ASN2 for asparagine synthesis. In asn2‐1 knockout and asn2‐2 knockdown lines, ASN2 disruption caused a defective growth phenotype and ammonium accumulation. The asn2 mutant leaves displayed a depleted asparagine and an accumulation of alanine, GABA, pyruvate and fumarate, indicating an alanine formation from pyruvate through the GABA shunt to consume excess ammonium in the absence of asparagine synthesis. By contrast, asparagine did not contribute to photorespiratory nitrogen recycle as photosynthetic net CO₂ assimilation was not significantly different between lines under both 21 and 2% O₂. ASN2 was found in phloem companion cells by in situ hybridization and immunolocalization. Moreover, lack of asparagine in asn2 phloem sap and lowered ¹⁵N flux to sinks, accompanied by the delayed yellowing (senescence) of asn2 leaves, in the absence of asparagine support a specific role of asparagine in phloem loading and nitrogen reallocation. We conclude that ASN2 is essential for nitrogen assimilation, distribution and remobilization (via the phloem) within the plant.     

Development and Characterization of Zein-Based Micro Carrier System for Sustained Delivery of Aceclofenac Sodium

Nonsteroidal anti-inflammatory drugs (NSAIDs) induce gastric injury on long-term usage. This study aims at reducing the side effect of NSAIDs by encapsulating in zein, an acid-resistant biopolymer. Aceclofenac-loaded zein microspheres were prepared by emulsification and solvent evaporation method. The stability of zein microspheres at gastric pH retarded the release of the entrapped drug and hence reduces the possibility of gastric injury. However, the in vitro release of aceclofenac was sustained up to 72 h at intestinal pH. Thus, zein microspheres pave the way for the development of safe and sustained delivery system for NSAIDs thereby achieving the desired therapeutic potential with reduced side effects for chronic inflammatory disorders.     

Tetratricopeptide Repeat Domain 9A Negatively Regulates Estrogen Receptor Alpha Activity

Tetratricopeptide repeat domain 9A (TTC9A) is a target gene of estrogen and progesterone. It is over-expressed in breast cancer. However, little is known about the physiological function of TTC9A. The objectives of this study were to establish a Ttc9a knockout mouse model and to study the consequence of Ttc9a gene inactivation. The Ttc9a targeting vector was generated by replacing the Ttc9a exon 1 with a neomycin cassette. The mice homozygous for Ttc9a exon 1 deletion appear to grow normally and are fertile. However, further characterization of the female mice revealed that Ttc9a deficiency is associated with greater body weight, bigger thymus and better mammary development in post-pubertal mice. Furthermore, Ttc9a deficient mammary gland was more responsive to estrogen treatment with greater mammary ductal lengthening, ductal branching and estrogen target gene induction. Since Ttc9a is induced by estrogen in estrogen target tissues, these results suggest that Ttc9a is a negative regulator of estrogen function through a negative feedback mechanism. This is supported by in vitro evidence that TTC9A over-expression attenuated ERα activity in MCF-7 cells. Although TTC9A does not bind to ERα or its chaperone protein Hsp90 directly, TTC9A strongly interacts with FKBP38 and FKBP51, both of which interact with ERα and Hsp90 and modulate ERα activity. It is plausible therefore that TTC9A negatively regulates ERα activity through interacting with co-chaperone proteins such as FKBP38 and FKBP51.     

1H NMR metabolomics reveals increased glutaminolysis upon overexpression of NSD3s or Pdp3 in Saccharomyces cerevisiae

NSD3s, the proline-tryptophan-tryptophan-proline (PWWP) domain-containing, short isoform of the human oncoprotein NSD3, displays high transforming properties. Overexpression of human NSD3s or the yeast protein Pdp3 in Saccharomyces cerevisiae induces similar metabolic changes, including increased growth rate and sensitivity to oxidative stress, accompanied by decreased oxygen consumption. Here, we set out to elucidate the biochemical pathways leading to the observed metabolic phenotype by analyzing the alterations in yeast metabolome in response to NSD3s or Pdp3 overexpression using ¹H nuclear magnetic resonance (NMR) metabolomics. We observed an increase in aspartate and alanine, together with a decrease in arginine levels, on overexpression of NSD3s or Pdp3, suggesting an increase in the rate of glutaminolysis. In addition, certain metabolites, including glutamate, valine, and phosphocholine were either NSD3s or Pdp3 specific, indicating that additional metabolic pathways are adapted in a protein-dependent manner. The observation that certain metabolic pathways are differentially regulated by NSD3s and Pdp3 suggests that, despite the structural similarity between their PWWP domains, the two proteins act by unique mechanisms and may recruit different downstream signaling complexes. This study establishes for the first time a functional link between the human oncoprotein NSD3s and cancer metabolic reprogramming.     

A non‐canonical role of the p97 complex in RIG‐I antiviral signaling

RIG‐I is a well‐studied sensor of viral RNA that plays a key role in innate immunity. p97 regulates a variety of cellular events such as protein quality control, membrane reassembly, DNA repair, and the cell cycle. Here, we report a new role for p97 with Npl4‐Ufd1 as its cofactor in reducing antiviral innate immune responses by facilitating proteasomal degradation of RIG‐I. The p97 complex is able to directly bind both non‐ubiquitinated RIG‐I and the E3 ligase RNF125, promoting K48‐linked ubiquitination of RIG‐I at residue K181. Viral infection significantly strengthens the interaction between RIG‐I and the p97 complex by a conformational change of RIG‐I that exposes the CARDs and through K63‐linked ubiquitination of these CARDs. Disruption of the p97 complex enhances RIG‐I antiviral signaling. Consistently, administration of compounds targeting p97 ATPase activity was shown to inhibit viral replication and protect mice from vesicular stomatitis virus (VSV) infection. Overall, our study uncovered a previously unrecognized role for the p97 complex in protein ubiquitination and revealed the p97 complex as a potential drug target in antiviral therapy.     

Mapping quantitative trait loci (QTLs) for fatty acid composition in an interspecific cross of oil palm

Background  

Marker Assisted Selection (MAS) is well suited to a perennial crop like oil palm, in which the economic products are not produced until several years after planting. The use of DNA markers for selection in such crops can greatly reduce the number of breeding cycles needed. With the use of DNA markers, informed decisions can be made at the nursery stage, regarding which individuals should be retained as breeding stock, which are satisfactory for agricultural production, and which should be culled. The trait associated with oil quality, measured in terms of its fatty acid composition, is an important agronomic trait that can eventually be tracked using molecular markers. This will speed up the production of new and improved oil palm planting materials.     

Ecdysteroids and meiotic reinitiation in Palaemon serratus (Crustacea Decapoda Natantia) and in Locusta migratoria (Insecta orthoptera). A comparative study

Summary

Meiotic reinitiation has been studied in Locusta migratoria and Palaemon serratus in relation to the titre of free ecdysteroids present in the maturing oocyte. In both species meiotic reinitiation is characterized by two meiotic arrests, in prophase I and in metaphase I, and the first meiotic resumption which leads to germinal vesicle breakdown (GVBD) is correlated with increasing titres of ecdysteroids in the oocyte. Meiotic reinitiation has been successfully triggered in the oocytes of both species by incubation with physiological doses of ecdysteroids.     

Fabrication of plumbagin on silver nanoframework for tunable redox modulation: Implications for therapeutic angiogenesis

The redox state of the endothelial cells plays a key role in the regulation of the angiogenic process. The modulation of the redox state of endothelial cells (ECs) could be a viable target to alter angiogenic response. In the present work, we synthesized a redox modulator by caging 5-hydroxy 2-methyl 1, 4-napthoquinone (Plumbagin) on silver nano framework (PCSN) for tunable reactive oxygen species (ROS) inductive property and tested its role in ECs during angiogenic response in physiological and stimulated conditions. In physiological conditions, the redox modulators induced the angiogenic response by establishing ECs cell–cell contact in tube formation model, chorio allontoic membrane, and aortic ring model. The molecular mechanism of angiogenic response was induced by vascular endothelial growth factor receptor 2 (VEGFR2)/p42-mitogen-activated protein kinase signaling pathway. Under stimulation, by mimicking tumor angiogenic conditions it induced cytotoxicity by generation of excessive ROS and inhibited the angiogenic response by the loss of spatiotemporal regulation of matrix metalloproteases, which prevents the tubular network formation in ECs and poly-ADP ribose modification of VEGF. The mechanism of opposing effects of PCSN was due to modulation of PKM2 enzyme activity, which increased the EC sensitivity to ROS and inhibited EC survival in stimulated condition. In normal conditions, the endogenous reactive states of NOX4 enzyme helped the EC survival. The results indicated that a threshold ROS level exists in ECs that promote angiogenesis and any significant enhancement in its level by redox modulator inhibits angiogenesis. The study provides the cues for the development of redox-based therapeutic molecules to cure the disease-associated aberrant angiogenesis.     

Evidence against the use of surrogates for biomonitoring of Neotropical floodplains

1. Community concordance measures the level of association between the compositional patterns shown by two groups of organisms. If strong community concordance occurs, one group could be used as a surrogate for another in conservation planning and biodiversity monitoring. In this study, we evaluated the variability in the strength of community concordance, the likely mechanisms underlying community concordance and the degree to which one community can predict another in a set of Neotropical floodplain lakes (Upper Paraná River floodplain, Brazil). 2. We used a data set including six aquatic communities: fish, macrophytes, benthic macroinvertebrates, zooplankton, phytoplankton and periphyton. We used Mantel and PROTEST approaches to evaluate the levels of community concordance in up to four sampling periods. Also, we used partial Mantel test and information about biotic interactions to investigate reasons for observed patterns of concordance. Finally, we used co‐correspondence analysis to evaluate the performance of one taxonomic group in predicting the structures of other communities. 3. The levels of community concordance varied over time for almost all cross‐taxa comparisons. Concordance between phytoplankton and periphyton probably resulted from similar responses to environmental gradients, whereas other patterns of concordance were likely generated by interactions among groups. However, the levels of predictability were low, and no particular taxonomic group significantly predicted all other groups. 4. The low and temporally variable levels of community concordance cast doubts on the use of surrogate groups for biodiversity management in Neotropical floodplains.     

Novel phenolic antioxidants as multifunctional inhibitors of inducible VCAM-1 expression for use in atherosclerosis

A series of novel phenolic compounds has been discovered as potent inhibitors of TNF-alpha-inducible expression of vascular cell adhesion molecule-1 (VCAM-1) with concurrent antioxidant and lipid-modulating properties. Optimization of these multifunctional agents led to the identification of 3a (AGI-1067) as a clinical candidate with demonstrated efficacies in animal models of atherosclerosis and hyperlipidemia.