The fslE Homolog, FTL_0439 (fupA/B), Mediates Siderophore-Dependent Iron Uptake in Francisella tularensis LVS ▿

The Gram-negative pathogen Francisella tularensis secretes a siderophore to obtain essential iron by a TonB-independent mechanism. The fslABCDE locus, encoding siderophore-related functions, is conserved among different Francisella strains. In the virulent strain Schu S4, fslE is essential for siderophore utilization and for growth under conditions of iron limitation. In contrast, we found that deletion of fslE did not affect siderophore utilization by the attenuated live vaccine strain (LVS). We found that one of the fslE paralogs encoded in the LVS genome, FTL_0439 (fupA/B), was able to partially complement a Schu S4 ΔfslE mutant for siderophore utilization. We generated a deletion of fupA/B in LVS and in the LVS ΔfslE background. The ΔfupA/B mutant showed reduced growth under conditions of iron limitation. It was able to secrete but was unable to utilize siderophore. Mutation of both fupA/B and fslE resulted in a growth defect of greater severity. The ΔfupA/B mutants showed a replication defect in J774.1A cells and decreased virulence following intraperitoneal infection in mice. Complementation of the ΔfupA/B mutation in cis restored the ability to utilize siderophore and concomitantly restored virulence. Our results indicate that fupA/B plays a significant role in the siderophore-mediated iron uptake mechanism of LVS whereas fslE appears to play a secondary role. Variation in iron acquisition mechanisms may contribute to virulence differences between the strains

Direct Observation of Intermediate State(s) in the Mechanistic Investigation of Domain Specific Protein-Surfactant Interaction

Introduction: Interaction of surfactants with proteins can decipher important information regarding the stability and behavior of proteins. For multi-domain proteins, these interactions vary domain wise and these details are crucial in understanding the contribution of different domains of the protein in its overall activity. Objective: The objective of the present work is to study the interaction of surfactants with domain III of Human Serum Albumin (HSA) and to compare the same with the global interaction. Methods: Interaction of the anionic Sodium Dodecyl Sulphate (SDS) and the Cationic Cetyltrimethylammonium Bromide (CTAB) surfactants with domain III of Human Serum Albumin (HSA) has been studied using 8-Anilino-1-Naphthalene-Sulphonate (ANS) as a fluorescent marker. Circular Dichroism (CD) spectroscopy has been used to study the protein-surfactant interaction for the overall protein. Results: SDS is found to interact sequentially with domain III of HSA having two detectable intermediate states in the binding process. In case of CTAB, we have observed only one intermediate state for its interaction with domain III. Although Quantum yield measurement can reflect the presence of such intermediate state, the overall conformational change of the HSA on addition of surfactants, studied by Circular Dichroism (CD) spectroscopy, and the ANS-Trp distance measurement by FRET could not resolve the presence of such intermediate states. The esterase activity of HSA in presence of different amount of surfactants is also in accordance with our above observation. Conclusion: The interaction of both the surfactants with HSA is found to be sequential in nature. The most important conclusion revealed from our study is that the nature of protein-surfactant interaction is not same throughout the entire protein. Our study reveals that different parts of the multi-domain HSA have different affinity to the surfactant molecules

The Dynamics of Finance-Growth-Inequality Nexus: Theory and Evidence for India

The purpose of this research study has been to expand our understanding of the finance-growth ‘nexus’ to finance-growth-inequality ‘nexus’ in the presence of both the formal and the informal sources of borrowing. Using empirical evidence of IHDS Survey data for two rounds the study attempts to assess the co-evolution of finance-growth-inequality in an intertemporal framework. The most important finding of the paper pertains to the econometric result that the household asset grows at the same rate independent of the source of loans - banks or moneylenders though the level effect (intercept) is higher if the loan is obtained from banks or lower if the household lives below poverty line. The same also holds for the rate of growth of per capita income. There is virtually no significant difference for the households living below poverty line (BPL) on the rate of growth of capital asset or income whether source of borrowing is bank or money lender. This is then formalized in a theoretical model of intertemporal choice of entrepreneur-investor to show that if there are both formal and informal sources of borrowing with a constraint on the formal sector borrowing and no constraint on the latter, then growth rates of asset and income are determined by the informal sector interest rate. The result can be generalised for any number of sources of borrowing. This questions the conventional wisdom regarding the policy aimed at financial inclusion. Inequality of income increases independent of the source of borrowing, though the BPL households are worse off in general

Conformational Fluctuation Dynamics of Domain I of Human Serum Albumin in the Course of Chemically and Thermally Induced Unfolding Using Fluorescence Correlation Spectroscopy

The present study elucidates the involvement of conformational fluctuation dynamics during chemically and thermally induced unfolding of human serum albumin (HSA) by fluorescence correlation spectroscopic (FCS) study, time-resolved fluorescence measurements, and circular dichroism (CD) spectroscopic methods. Two fluorescent probes, tetramethylrhodamine-5-maleimide (TMR) and <i>N</i>-(7-dimethylamino-4-methylcoumarin-3-yl) iodoacetamide (DACIA) were used to selectively label the domain I of HSA through the reaction with cys-34 for these studies. The guanidine hydrochloride (GnHCl) induced global structural change of HSA is monitored through its hydrodynamic radius (<i>r</i>_H) and CD response, which is found to be two step in nature. In FCS experiment, along with the diffusion time component we have observed an exponential relaxation time component (τ_R) that has been ascribed to the concerted chain dynamics of HSA. Unlike in the global structural change, we found that the τ_R value changes in a different manner in the course of the unfolding. The dependence of τ_R on the concentration of GnHCl was best fitted with a four state model, indicating the involvement of two intermediate states during the unfolding process, which were not observed through the CD response and <i>r</i>_H data. The fluorescence lifetime measurement also supports our observation of intermediate states during the unfolding of HSA. However, no such intermediate states were observed during thermally induced unfolding of HSA

Benzo(a)pyrene induced p53 mediated male germ cell apoptosis: Synergistic protective effects of curcumin and resveratrol

B(a)P (Benzo(a)pyrene) is an environmental toxicant that induces male germ cell apoptosis. Curcumin and resveratrol are phytochemicals with cytoprotective and anti-oxidative properties. At the same time resveratrol is also a natural Aryl hydrocarbon Receptor (AhR) antagonist. Our present study in isolated testicular germ cell population from adult male Wistar rats, highlighted the synergistic protective effect of curcumin and resveratrol against B(a)P induced p53 mediated germ cell apoptosis. Curcumin-resveratrol significantly prevented B(a)P induced decrease in sperm cell count and motility, as well as increased serum testosterone level. Curcumin-resveratrol co-treatment actively protected B(a)P induced testicular germ cell apoptosis. Curcumin-resveratrol co-treatment decreased the expression of pro-apoptotic proteins like cleaved caspase 3, 8 and 9, cleaved PARP, Apaf1, FasL, tBid. Curcumin-resveratrol co-treatment decreased Bax/Bcl2 ratio, mitochondria to cytosolic translocation of cytochrome c and activated the survival protein Akt. Curcumin-resveratrol decreased the expression of p53 dependent apoptotic genes like Fas, FasL, Bax, Bcl2 and Apaf1. B(a)P induced testicular ROS (Reactive Oxygen Species) generation and oxidative stress were significantly ameliorated with curcumin and resveratrol. Curcumin-resveratrol co-treatment prevented B(a)P induced nuclear translocation of AhR and CYP1A1(Cytochrome P4501A1) expression. The combinatorial treatment significantly inhibited B(a)P induced ERK 1/2, p38 MAPK and JNK 1/2 activation. B(a)P treatment increased the expression of p53 and its phosphorylation (p53 ser 15). Curcumin-resveratrol co-treatment significantly decreased p53 level and its phosphorylation (p53 ser 15). The study concludes that curcumin-resveratrol synergistically modulated MAPKs and p53, prevented oxidative stress, regulated the expression of pro and anti-apoptotic proteins as well as the proteins involved in B(a)P metabolism thus protected germ cells from B(a)P induced apoptosis

A Novel Feature Representation for Prediction of Global Horizontal Irradiance Using a Bidirectional Model

Complex weather conditions—in particular clouds—leads to uncertainty in photovoltaic (PV) systems, which makes solar energy prediction very difficult. Currently, in the renewable energy domain, deep-learning-based sequence models have reported better results compared to state-of-the-art machine-learning models. There are quite a few choices of deep-learning architectures, among which Bidirectional Gated Recurrent Unit (BGRU) has apparently not been used earlier in the solar energy domain. In this paper, BGRU was used with a new augmented and bidirectional feature representation. The used BGRU network is more generalized as it can handle unequal lengths of forward and backward context. The proposed model produced 59.21%, 37.47%, and 76.80% better prediction accuracy compared to traditional sequence-based, bidirectional models, and some of the established states-of-the-art models. The testbed considered for evaluation of the model is far more comprehensive and reliable considering the variability in the climatic zones and seasons, as compared to some of the recent studies in India