Platinum(II) and palladium(II) complexes with 2-Acetyl pyridine 4N-ethyl thiosemicarbazone able to overcome the cis-Platin resistance. Structure, antibacterial activity and DNA strand breakage

The reactions of Pd(II) and Pt(II) with 2-Acetyl Pyridine N(4)-Ethyl-Thiosemicarbazones, HAc4Et and 2-Acetyl Pyridine N(4)-1-(2-pyridyl)-piperazinyl Thiosemicarbazone, HAc4PiPiz and 2-Formyl Pyridine N(4)-1-(2-pyridyl)-piperazinyl Thiosemicarbazone, HFo4PiPiz afforded the complexes, [Pd(Ac4Et)], 1, [Pd(HAc4Et)₂]Cl₂, 2 and [Pd(Ac4Et)₂], 3[Pt(Ac4Et)], 4, [Pt(HAc4Et)₂]Cl₂, 5, [Pt(Ac4Et)₂], 6 and [Pd(Fo4PipePiz)Cl], 7, [Pd(Fo4PipePiz)₂], 8, [Pd(Ac4PipePiz)Cl], 9 and [Pd(Ac4PipePiz)₂], 10. The crystal structure of the complex [Pt(Ac4Et)₂], 6 has been solved. The platinum(II) atom is in a square planar environment surrounded by two cis nitrogen atoms and two cis sulfur atoms. The ligands are not equivalent, one being tridentate with (N,N,S) donation, the other being monodentate using only the sulfur atom to coordinate to the metal. The tridentate ligand shows a Z, E, Z configuration while the monodentate ligand shows an E, E, Z. Inter-molecular hydrogen bonds stabilize the structure, while the crystal packing is determined by –, and Pt – C interactions. The antibacterial effect of Pd(II) and Pt(II) complexes were studied in vitro. The complexes were found to have effect on Gram(+) bacteria, while the same complexes showed no bactericidal effect on Gram(–) bacteria. The effect of the Pd(II) and Pt(II) complexes on the in vitro DNA strand breakage was studied by agarose gel electrophoresis. The complexes 1-6 were found to exhibit a cytotoxic potency in a very low micromolar range and to be able to overcome the cisplatin resistance of A2780/Cp8 cells (Kovala-Demertzi et al. 2000).     

Himalayan musk deer (Moshcus leucogaster) behavior at latrine sites and their implications in conservation

Elusive species often use latrines which also serves as communication and information hubs. Thus, studying behavior at latrines may provide critical insights into the species’ ecology and behavior. While it is established that musk deer use latrines for defecating, very little is known about the endangered Himalayan musk deer (Moschus leucogaster) and their latrines. We examined musk deer behavior from the various video clips lasting 238 min altogether, captured at latrine sites during both breeding and non‐breeding seasons in the Annapurna Conservation Area of Nepal. A total of 428 visits by musk deer and 479 behavioral events by them were captured. We constructed an ethogram to describe musk deer behavior and compared behavior across individuals and sex using parametric and non‐parametric tests. We found that musk deer are crepuscular and nocturnal animals. Both male and female musk deer repeatedly and independently visited shared latrine sites as well as exclusively used latrine sites. The proportion of male musk deer visited latrine sites were significantly higher than that of female musk deer. Hence, male musk deer were found more active (>2 times) than females during both seasons. The most frequently observed behavioral activities at the latrine sites were defecating, sniffing and browsing, followed by scrapping and covering, and ignoring the latrine sites. The defecating and sniffing activity were performed throughout breeding and non‐breeding seasons to establish communication among peers and to claim territory. Based on the behaviors observed at the latrine sites, we can presume that Himalayan musk deer likely use latrines to convey various messages, including personality, maturity, sexual status, and territory marking among conspecifics. These findings of this study can be used for the conservation of musk deer in its natural habitat and replicated in captivity to enhance breeding performance that improves long‐term conservation prospects for this species.     

Localized exocytosis detected by spatially resolved amperometry in single pancreatic β-cells

Spatially resolved measurements of exocytosis in pancreatic beta-cells were made using amperometry with 1-microm radius electrodes. These measurements revealed that certain portions of a cell actively undergo exocytosis following stimulation with depolarizing agents, but other regions are inactive. The amperometric measurements were compared to measurements made with the membrane indicator dye, FM1-43, which showed uneven increases in fluorescence around the surface of the cell, with amperometric secretion being detected only at the brightest regions. In some instances, a large number of exocytotic events were detected from one electrode position. The number of events was larger than what would be expected based on the number of vesicles that could fit under an electrode of the dimensions used. These results suggest a mechanism of vesicle traffic that allows multiple fusions at a small membrane area.     

Chronic hyperhomocysteinemia causes vascular remodelling by instigating vein phenotype in artery

In the present study we tested the hypothesis whether hyperhomocysteinemia, an elevated homocysteine level, induces venous phenotype in artery. To test our hypothesis, we employed wild type (WT) and cystathionine β-synthase heterozygous (+/-) (CBS+/-) mice treatment with or without folic acid (FA). Aortic blood flow and velocity were significantly lower in CBS+/-mice compared to WT. Aortic lumen diameter was significantly decreased in CBS+/-mice, whereas FA treatment normalized it. Medial thickness and collagen were significantly increased in CBS+/-aorta, whereas elastin/collagen ratio was significantly decreased. Superoxide and gelatinase activity was significantly high in CBS+/-aorta vs WT. Western blot showed significant increase in MMP-2, -9,-12, TIMP-2 and decrease in TIMP-4 in aorta. RT-PCR revealed significant increase of vena cava marker EphB4, MMP-13 and TIMP-3 in aorta. We summarize that chronic HHcy causes vascular remodelling that transduces changes in vascular wall in a way that artery expresses vein phenotype.     

Cardiac matrix: A clue for future therapy

Cardiac muscle is unique because it contracts ceaselessly throughout the life and is highly resistant to fatigue. The marvelous nature of the cardiac muscle is attributed to its matrix that maintains structural and functional integrity and provides ambient micro-environment required for mechanical, cellular and molecular activities in the heart. Cardiac matrix dictates the endothelium myocyte (EM) coupling and contractility of cardiomyocytes. The matrix metalloproteinases (MMPs) and their tissue inhibitor of metalloproteinases (TIMPs) regulate matrix degradation that determines cardiac fibrosis and myocardial performance. We have shown that MMP-9 regulates differential expression of micro RNAs (miRNAs), calcium cycling and contractility of cardiomyocytes. The differential expression of miRNAs is associated with angiogenesis, hypertrophy and fibrosis in the heart. MMP-9, which is involved in the degradation of cardiac matrix and induction of fibrosis, is also implicated in inhibition of survival and differentiation of cardiac stem cells (CSC). Cardiac matrix is distinct because it renders mechanical properties and provides a framework essential for differentiation of cardiac progenitor cells (CPC) into specific lineage. Cardiac matrix regulates myocyte contractility by EM coupling and calcium transients and also directs miRNAs required for precise regulation of continuous and synchronized beating of cardiomyocytes that is indispensible for survival. Alteration in the matrix homeostasis due to induction of MMPs, altered expression of specific miRNAs or impaired signaling for contractility of cardiomyocytes leads to catastrophic effects. This review describes the mechanisms by which cardiac matrix regulates myocardial performance and suggests future directions for the development of treatment strategies in cardiovascular diseases.     

Synthesis and biological activities of 4-N-(anilinyl-n-[oxazolyl])-7-chloroquinolines (n=3' or 4') against Plasmodium falciparum in in vitro models

The synthesis (Pd-mediated coupling strategy) and characterization (NMR, IR, elemental analysis, etc.) of a short series of quinoline-oxazole hybrid compounds has been carried out. These materials are found to be moderately active against Plasmodium falciparum in vitro, with activities in the sub-micromolar range, and to display acceptable cytotoxicity to mononuclear leukocytes. Chemical modification strategies, with the intention to increase the biological potency of this new class of anti-malarial agents, are discussed.     

Ecological correlates of Himalayan musk deer Moschus leucogaster

Himalayan musk deer (Moschus leucogaster; hereafter musk deer) are endangered as a result of poaching and habitat loss. The species is nocturnal, crepuscular, and elusive, making direct observation of habitat use and behavior difficult. However, musk deer establish and repeatedly use the same latrines for defecation. To quantify musk deer habitat correlates, we used observational spatial data based on presence–absence of musk deer latrines, as well as a range of fine spatial‐scale ecological covariates. To determine presence–absence of musk deer, we exhaustively searched randomly selected forest trails using a 20‐m belt transect in different study sites within the Neshyang Valley in the Annapurna Conservation Area. In a subsequent way, study sites were classified as habitat or nonhabitat for musk deer. A total of 252 plots, 20 × 20 m, were systematically established every 100 m along 51 transects (each ~0.5 km long) laid out at different elevations to record a range of ecological habitat variables. We used mixed‐effect models and principal component analysis to characterize relationships between deer presence–absence data and habitat variables. We confirmed musk deer use latrines in forests located at higher elevations (3,200–4,200 m) throughout multiple seasons and years. Himalayan birch (Betula utilis) dominated forest, mixed Himalayan fir (Abies spectabilis), and birch forest were preferred over pure Himalayan fir and blue pine (Pinus wallichiana) forest. Greater crown cover and shrub diversity were associated with the presence of musk deer whereas tree height, diameter, and diversity were weakly correlated. Topographical attributes including aspect, elevation, distance to water source, and slope were also discriminated by musk deer. Over‐ and understory forest management can be used to protect forests likely to have musk deer as predicted by the models to ensure long‐term conservation of this rare deer.     

MicroRNA-133a regulates DNA methylation in diabetic cardiomyocytes

We tested the hypothesis that miR-133a regulates DNA methylation by inhibiting Dnmt-1 (maintenance) and Dnmt-3a and -3b (de novo) methyl transferases in diabetic hearts by using Ins2(+/-) Akita (diabetic) and C57BL/6J (WT), mice and HL1 cardiomyocytes. The specific role of miR-133a in DNA methylation in diabetes was assessed by two treatment groups (1) scrambled, miR-133a mimic, anti-miR-133a, and (2) 5mM glucose (CT), 25mM glucose (HG) and HG+miR-133a mimic. The levels of miR-133a, Dnmt-1, -3a and -3b were measured by multiplex RT-PCR, qPCR and Western blotting. The results revealed that miR-133a is inhibited but Dnmt-1 and -3b are induced in Akita suggesting that attenuation of miR-133a induces both maintenance (Dnmt-1) - and de novo - methylation (Dnmt-3b) in diabetes. The up regulation of Dnmt-3a in Akita hearts elicits intricate and antagonizing interaction between Dnmt-3a and -3b. In cardiomyocytes, over expression of miR-133a inhibits but silencing of miR-133a induces Dnmt-1, -3a and -3b elucidating the involvement of miR-133a in regulation of DNA methylation. The HG treatment up regulates only Dnmt-1 and not Dnmt-3a and -3b suggesting that acute hyperglycemia triggers only maintenance methylation. The over expression of miR-133a mitigates glucose mediated induction of Dnmt-1 illustrating the role of miR-133a in regulation of DNA methylation in diabetes.