Strontium to calcium (Sr/Ca) ratio in otolith as a tool for stock discrimination of oilsardine and mackerel

Otoliths are found in the membranous labyrinth of the inner ear of teleost fish and serve mainly in balancing the organism. They are composed of calcium carbonate and are deposited rhythmically as aragonite crystals within a protein matrix. They have long been used in fish aging studies. Recently, changes in the strontium (Sr): calcium (Ca) ratios in otoliths have received increasing attention, as these provide a method of reconstructing environmental history of the fish. Strontium is a calcium analogue sharing a similar crystal ionic radius and can substitute for Ca in the aragonite lattice of otoliths

Monomeric and Dimeric CXCL8 Are Both Essential for In Vivo Neutrophil Recruitment

Rapid mobilization of neutrophils from vasculature to the site of bacterial/viral infections and tissue injury is a critical step in successful resolution of inflammation. The chemokine CXCL8 plays a central role in recruiting neutrophils. A characteristic feature of CXCL8 is its ability to reversibly exist as both monomers and dimers, but whether both forms exist in vivo, and if so, the relevance of each form for in vivo function is not known. In this study, using a ‘trapped’ non-associating monomer and a non-dissociating dimer, we show that (i) wild type (WT) CXCL8 exists as both monomers and dimers, (ii) the in vivo recruitment profiles of the monomer, dimer, and WT are distinctly different, and (iii) the dimer is essential for initial robust recruitment and the WT is most active for sustained recruitment. Using a microfluidic device, we also observe that recruitment is not only dependent on the total amount of CXCL8 but also on the steepness of the gradient, and the gradients created by different CXCL8 variants elicit different neutrophil migratory responses. CXCL8 mediates its function by binding to CXCR2 receptor on neutrophils and glycosaminoglycans (GAGs) on endothelial cells. On the basis of our data, we propose that dynamic equilibrium between CXCL8 monomers and dimers and their differential binding to CXCR2 and GAGs mediates and regulates in vivo neutrophil recruitment. Our finding that both CXCL8 monomer and dimer are functional in vivo is novel, and indicates that the CXCL8 monomer-dimer equilibrium and neutrophil recruitment are intimately linked in health and disease

Multiphasic inhibition of mild steel corrosion in H2S gas environment

Compounds like Octylpalmamide (OTP), Octylsteramide (OTS), Octylcaprylamide (OTC), Octylbenzamide (OTB) and one complex compound Dicyclohexylaminebenzotriazole (DCHAB) were synthesized and characterized by Fourier Transform infrared spectroscopy (FTIR). These synthesized compounds were drawn as volatile corrosion inhibitor (VCI) in H2S gas environment on mild steel (MS) at 323 K. Surface morphology and elemental analysis have been examined by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDX) respectively. Various studies like weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used for evaluating corrosion rate, inhibitor behaviour and change in charge transfer resistance (Rct) value, respectively. All the above experiments proved that DCHAB was the most efficacious corrosion inhibitor. Adsorption behaviour of the inhibitor was evaluated and it obeys Langmuir adsorption isotherm

Role of Intramolecular Disulfides in Stability and Structure of a Noncovalent Homodimer

The importance of intramolecular disulfides in a noncovalent dimeric protein interleukin-8 (IL-8) has been studied by replacing cysteines in each of the two disulfide pairs with α-aminobutyric acid (CH2-SH → CH2-CH3). Both disulfide mutants are less stable and exist as molten globules in the monomeric state. Interestingly, both mutants dimerize, though with slightly lower affinities compared to the native protein. NMR studies suggest a molten globule-like structure also in the dimeric state. Structures, sequence analysis, and mutagenesis studies have shown that the conserved hydrophobic residues are packed against each other in the protein core and that H bonding and van der Waals interactions stabilize the dimer interface. Deleting either disulfide in IL-8 results in substantial loss in receptor activity, indicating that both disulfides are critical for function in the folded protein. These data together suggest that the packing interactions of the hydrophobic core determine IL-8 monomer fold, that disulfides play only a marginal role in dimer formation, and that the stability imparted by the disulfides is intimately coupled to fold and function

Molecular docking approach on the binding stability of derivatives of phenolic acids (DPAs) with Human Serum Albumin (HSA): Hydrogen-bonding versus hydrophobic interactions or combined influences?

Molecular docking (Mol.Doc) techniques were employed to ascertain the binding affinity and energetics of hydroxy derivatives of benzoic and cinnamic acids extract from Psidium guajava L. with Human Serum Albumin (HSA). Caffeic acid (CA), Ferullic acid (FA), Sinapic acid (SA), Syringic acid (SyA) and Vanillic acid (VA) are the derivatives phenolic acids (DPA) employed in docking studies which acts as the guest molecule. Docking of various feasible conformers of DPA with HSA (host) was explored and these conformers were categorized based on the docking score which is correlated to the binding energy (BE) and the stability depends upon the molecular interactions. Among the phenolic acids, SA-HSA complex was energetically more favorable and feasible based on BE and the order of binding stability upon complex formation of various DPA-HSA follows the order SA > FA = CA > VA > SyA, though SA and SyA are structurally similar to each other, likewise FA and VA exhibit a similar structure. The stability upon complex formation is correlated to the docking of the guest molecule in the binding domains of HSA and several molecular interactions. Hydrogen-bonding (HB) interaction governs the stability of host-guest complex is established. Interestingly, the presence of multiple hydrophobic interactions (pi-pi, pi-alkyl, pi-cation or anion, pi-sigma and pi-amide) competes over HB interaction in several conformers resulting in a decrease in BE. We report that SA acts as an excellent site selective and site-specific ligand that prefers to dock in Sudlow binding site II comprising of sub domains IIIA and IIIB respectively. However, all other phenolic acids do not behave neither as site selective nor site specific ligand such that they prefer to reside both in site II and site III (non-Sudlow binding site) of HSA. We authenticate that all the DPA as well as the amino acid moieties in HSA act as HB donor as well as acceptor sites apart from several hydrophobic interactions. We further establish that all the DPA has the least probable affinity to reside in binding site I (warfarin binding site), whereas sub domain IIIA of site II is the most preferred site which is energetically most favoured among all the sub domains

G2/M-Phase-Inhibitory Mitochondrial-Depolarizing Re(I)/Ru(II)/Ir(III)-2,2′-Bipyrimidine-Based Heterobimetallic Luminescent Complexes: An Assessment of In Vitro Antiproliferative Activity and Bioimaging for Targeted Therapy toward Human TNBC Cells

Triple-negative breast cancer (TNBC) is an extremely vicious subtype of human breast cancer having the worst prognosis along with strong invasive and metastatic competency. Hence, it can easily invade into blood vessels, and presently, no targeted therapeutic approach is available to annihilate this type of cancer. Metal complexes have successfully stepped into the anticancer research and are now being applauded due to their anticancer potency after the discovery of cisplatin. Many of these metal complexes are also well recognized for their activity toward breast cancer. As the TNBC is a very dangerous subtype and has long been a challenging ailment to treat, we have intended to develop a few brand new mixed metallic Ru(II)/Ir(III)/Re(I)-2,2′-bipyrimidine complexes [L′Re2], [L′RuRe], and [L′IrRe] to abate the unbridled proliferation of TNBC cells. The potency of the complexes against TNBC cells has been justified using MDA-MB-468 TNBC cell lines where complex [L′IrRe] has displayed significant potency among all the three complexes with an IC50 value of 24.12 μM. The complex [L′IrRe] has been competent to cause apoptosis of TNBC cells through inhibition of the G2/M phase in the cell cycle in association with a profuse amount of ROS generation and mitochondrial depolarization