Features of 80S mammalian ribosome and its subunits

It is generally believed that basic features of ribosomal functions are universally valid, but a systematic test still stands out for higher eukaryotic 80S ribosomes. Here we report: (i) differences in tRNA and mRNA binding capabilities of eukaryotic and bacterial ribosomes and their subunits. Eukaryotic 40S subunits bind mRNA exclusively in the presence of cognate tRNA, whereas bacterial 30S do bind mRNA already in the absence of tRNA. 80S ribosomes bind mRNA efficiently in the absence of tRNA. In contrast, bacterial 70S interact with mRNA more productively in the presence rather than in the absence of tRNA. (ii) States of initiation (Pi), pre-translocation (PRE) and post-translocation (POST) of the ribosome were checked and no significant functional differences to the prokaryotic counterpart were observed including the reciprocal linkage between A and E sites. (iii) Eukaryotic ribosomes bind tetracycline with an affinity 15 times lower than that of bacterial ribosomes (Kd 30 μM and 1–2 μM, respectively). The drug does not effect enzymatic A-site occupation of 80S ribosomes in contrast to non-enzymatic tRNA binding to the A-site. Both observations explain the relative resistance of eukaryotic ribosomes to this antibiotic

The potential of vacuum therapy in the treatment of a newborn infant with severe thermal injury

The paper describes a clinical case of successful combination therapy in a newborn infant with severe thermal injury. When admitted to the hospital, the infant was diagnosed with third-degree flame burn covering 75% of the body surface and shock. Specialized emergency care involved antishock measures and replacement of vital functions, stepwise surgical interventions aimed to excise necrotic tissues and to restore lost skin tissue, and antimicrobial and symptomatic therapies. Topical treatment included the use of current wound coatings. Skin autocells were used for significant skin defect. Aacuum therapy was performed to stimulate repair processes and to prepare wounds for further skin plasty. The techniques of vacuum therapy included RENAS\S-GO and PICO apparatuses. Its efficiency was evaluated by microbiological, immunohistochemical, and planimetric examinations. Analysis of the decontaminating impact of a vacuum coating could establish its substantial effect in reducing wound bacterial contamination by 65% in the study group and by an average of 21% in the comparison group. That of immunohistochemical findings during vacuum therapy could reveal the high expression of two markers characterizing wound an-giogenesis. Comparative analysis of planimetric readings showed no significant differences in the use of vacuum therapy and current wound coatings. Thus, negative-pressure therapy creates favorable conditions for a wound healing process, providing effective wound decontamination and stimulating granulation tissue maturation as a factor to prepare for skin plasty

Structural Snapshots of Actively Translating Human Ribosomes

Summary Macromolecular machines, such as the ribosome, undergo large-scale conformational changes during their functional cycles. Although their mode of action is often compared to that of mechanical machines, a crucial difference is that, at the molecular dimension, thermodynamic effects dominate functional cycles, with proteins fluctuating stochastically between functional states defined by energetic minima on an energy landscape. Here, we have used cryo-electron microscopy to image ex-vivo-derived human polysomes as a source of actively translating ribosomes. Multiparticle refinement and 3D variability analysis allowed us to visualize a variety of native translation intermediates. Significantly populated states include not only elongation cycle intermediates in pre- and post-translocational states, but also eEF1A-containing decoding and termination/recycling complexes. Focusing on the post-translocational state, we extended this assessment to the single-residue level, uncovering striking details of ribosome-ligand interactions and identifying both static and functionally important dynamic elements

PHYSIOLOGICAL AND BIOCHEMICAL ASPECTS OF REPRODUCING THE WILD LONG-RHIZOME MORPHOTYPE OF <i> MEDICAGO FALCATA </i> L. UNDER CULTIVATION

Morphology, nitrogen-fixing activity and seed productivity of the introduced wild long-rhizome yellow alfalfa (Medicago falcata L.) under exogenous treatment with microbial preparations and phytohormone (homobrassinolide) were studied in field experiments. It was revealed that growth activators increase seed productivity and nitrogen-fixing activity in the cultivated taproot alfalfa type and, on the whole, have no effect on metabolism in the long-rhizome morphotype plants. To solve the problem it is necessary to develop Rhizobium preparations increasing nitrogen-fixing activity of the long-rhizome alfalfa plants on the basis of natural isolates and the use of phytohormones with due regard to the peculiarities of the ontogenesis of the long-rhizome M. falcata morphotype