Comparative Assessment of Forage Legume and Grass-legume Mixture Quality Ensiled with Biological and Chemical Preservatives

Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - The paper presents research and production studies evaluating the forage legume ensiling quality treated with...     

Dual effects of ATP on isolated arteries of the bovine eye

Although the presence of purinoreceptors has been shown in many human and animal arteries, there is few data yet about their role in the arteries of the eye. The purpose of the present study was to evaluate the effects of several agonists of purinoreceptors on isolated arteries of the bovine eye. Responses of isolated preparations of bovine ophthalmic (OA) and posterior ciliary arteries (PCA) to agonists of purinoreceptors (ATP, α,β-methylene-ATP-α,β-meATP, 2-methylthioATP-2meSATP, uridine-5'-triphosphate-UTP) as well as agonists of adreno-, cholino-, adenosine and histamine receptors were recorded by a standard organ bath method. ATP induced contractions of the intact vessels but caused relaxation of α,β-meATP-pretreated arteries. Contractile responses of PCA to high concentrations of ATP and α,β-meATP were significantly stronger than responses of OA, as well as relaxative responses to ATP and adenosine were significantly stronger in PCA than in OA. We suggest that there are several subtypes of functionally active purinoreceptors in both OA and PCA, although the potency of agonists of purinoreceptors to produce mechanical responses is higher in PCA than in OA. Purinoreceptors can be potential targets for new drugs, treating vascular pathology of the eye.     

Geometrical confinement of Gd(DOTA) molecules within mesoporous silicon nanoconstructs for MR imaging of cancer

Porous silicon has been used for the delivery of therapeutic and imaging agents in several biomedical applications. Here, mesoporous silicon nanoconstructs (SiMPs) with a discoidal shape and a sub-micrometer size (1000 × 400 nm) have been conjugated with gadolinium-tetraazacyclododecane tetraacetic acid Gd(DOTA) molecules and proposed as contrast agents for Magnetic Resonance Imaging. The surface of the SiMPs with different porosities – small pore (SP: ∼5 nm) and huge pore (HP: ∼40 nm) – and of bulk, non-porous silica beads (1000 nm in diameter) have been modified with covalently attached (3-aminopropyl)triethoxysilane (APTES) groups, conjugated with DOTA molecules, and reacted with an aqueous solution of GdCl₃. The resulting Gd(DOTA) molecules confined within the small pores of the Gd-SiMPs achieve longitudinal relaxivities r₁ of ∼17 (mM s)⁻¹, which is 4 times greater than for free Gd(DOTA). This enhancement is ascribed to the confinement and stable chelation of Gd(DOTA) molecules within the SiMP mesoporous matrix. The resulting nanoconstructs possess no cytotoxicity and accumulate in ovarian tumors up to 2% of the injected dose per gram tissue, upon tail vein injection. All together this data suggests that Gd-SiMPs could be efficiently used for MR vascular imaging in cancer and other diseases.     

The effects of ATP on the contractions of rat and mouse fast skeletal muscle

Introduction: The aim of this study was to compare the effects of adenosine-5'-triphosphate (ATP) and adenosine on the contractility of rodent extensor digitorum longus (EDL) muscle at normal and low temperatures. Methods: Contractions of rat and mouse isolated EDL were induced by either electrical stimulation (ES) or exogenous carbachol and recorded in the presence of ATP or adenosine (both at 100 μM). Results: ATP at all temperatures caused a decrease of the contractions induced by carbachol in rat and mouse EDL and ES-induced contractions in rat EDL, while it potentiated the ES-induced contractions of mouse EDL. Adenosine reduced the contractility of rat and mouse EDL evoked by ES and did not affect the carbachol-induced contractions of rat and mouse EDL at any temperature. Discussion: Under various temperature conditions, ATP inhibits pre- but potentiates postsynaptic processes in the mouse EDL; in the rat EDL ATP causes only inhibition of neuromuscular conduction. Muscle Nerve 59:509–516, 2019     

Mechanical Properties of Cubene Crystals

The fullerene family, whose most popular members are the spherical C60 and C70 molecules, has recently added a new member, the cube-shaped carbon molecule C8 called a cubene. A molecular crystal based on fullerenes is called fullerite. In this work, based on relaxational molecular dynamics, two fullerites based on cubenes are described for the first time, one of which belongs to the cubic system, and the other to the triclinic system. Potential energy per atom, elastic constants, and mechanical stress components are calculated as functions of lattice strain. It has been established that the cubic cubene crystal is metastable, while the triclinic crystal is presumably the crystalline phase in the ground state (the potential energies per atom for these two structures are −0.0452 and −0.0480 eV, respectively).The cubic phase has a lower density than the monoclinic one (volumes per cubene are 101 and 97.7 Å3). The elastic constants for the monoclinic phase are approximately 4% higher than those for the cubic phase. The presented results are the first step in studying the physical and mechanical properties of C8 fullerite, which may have potential for hydrogen storage and other applications. In the future, the influence of temperature on the properties of cubenes will be analyzed.     

Effects of ATP and adenosine on contraction amplitude of rat soleus muscle at different temperatures

Introduction: The aim of this study was to evaluate the effects of adenosine 5′‐triphosphate (ATP) and adenosine on the contractility of mammalian skeletal muscle under hypothermic conditions. Methods: Contractions of isolated rat soleus muscle were induced by either electrical stimulation (ES) or carbachol at physiological temperatures (37°C) and hypothermic conditions (30–14°C) and recorded in the presence of ATP, adenosine, suramin, and 8‐(p‐sulfophenyl)‐theophylline (8‐SPT). Results: At 37°C, incubation of the muscles with ATP inhibited ES‐induced contractions; the inhibitory effect of ATP disappeared at 14°C. Adenosine inhibited ES‐induced contractions at all temperature levels; 8‐SPT fully prevented the action of adenosine. ATP and adenosine did not significantly affect carbachol‐induced contractions at 37°C, while at lower temperatures ATP potentiated them. Suramin fully prevented effects of ATP. Conclusions: ATP is involved in both pre‐ and postsynaptic regulation of rat soleus muscle contractility, and these processes are significantly more pronounced at low temperatures. Muscle Nerve 55 : 417–423, 2017