Isoenzymes of human blood cholinesterases and their genetic control

Acetylcholinesterase from human erythrocytes solubilized by 1% Triton X-100 was resolved using polyacrylamide gel electrophoresis into two components. The first one (fast) is more firmly bound to cell membranes than the other. The existence of multiple forms (C1-C4) of serum cholinesterase-1 (CHE1) has been established. Electrophoresis in acid medium (pH 4.8) permits to detect the C5 component and a group of supplementary isoenzymes of cholinesterase-2. Individual differences observed in patterns of the CHE2 isozymes are controlled by a pair of autosomal codominant alleles Che2A and Che2B. The serum of subjects with phenotypes Che2AB(C5+) and Che2BB(C5-) showed on the average equal level of cholinesterase activity.     

Interaction of the photosystem 1 reaction center with antenna chlorophyll in a pigment-protein complex isolated from pea chloroplasts

Using a specially developed phosporoscopic attachment to spectropolarimeter, light induced spectra of circular dichroism (CD) in region 600-750 nm were measured for a pigment protein complex of photosystem 1 (PC-1) isolated from pea chloroplast (chlorophyll : P700 = 40). Minor components at 672 and 678 nm are observed in light induced spectra besides the components of dimer splitting of P700 Qy transition at 691 and 698 nm. Haussian deconvolution of light induced CD spectra of P700 and low temperature CD spectrum of PC-1 indicates that minor components are due to forms of antenna chlorophylls Chl672 and Chl678, rotational strength of that is changed by 2-4% as a result of P700 oxidation. Long term incubation of PC-1 with Triton X-100 inhibits P700 and destroys longwave optically active chlorophyll forms. A strong relation between dichroic density of 693 nm band in CD spectrum of PC-1 and the value of light induced absorption change at 698 nm could be used to determine P700 concentration on the basis of CD spectrum of PC-1. Such a relation shows that Chl693 is an important component of photo-system 1 reaction center. It is suggested that P700 is not an isolated dimer but it is included in the local complex from 8-10 chlorophyll molecules (Chl672, Chl678, Chl686, Chl693).     

Dependence of skeletal muscle fatigue on the membrane polarization of the different types of muscle fibers in tourniquet shock

Fatigue, polarization level and excitability of striated muscle fibers from ischemia zone were studied on experimental rats under the tourniquet shock. It was established that violation-mediated contraction and fatigue of skeletal muscle was associated with a decrease in a number of muscle fibers with high level of MPP. The article discussed the mechanisms of fatigue and depolarization of muscle fibres in tourniquet shock.     

A new pathogenic trait encoded by Yersinia pseudotuberculosis pVM82 plasmid

The strains of Yersinia pseudotuberculosis isolated from patients in the course of outbreaks of infection (epidemic strains) were found to possess at least two plasmids with molecular masses of 45 and 82 MD. In contrast, the strains obtained in sporadic cases harbored different sets of plasmids, but never the 82 MD plasmids. These plasmids designated pVM82 and isolated from strains of different geographic regions of the country were identical. pVM82 have no homology with Y. pestis plasmids of the similar size coding for the FraI antigen. The pVM82 DNA was found to be composed of the 57 MD plasmid DNA and the 25 MD fragment of Y. pseudotuberculosis DNA. Using Western blot hybridization technique it was shown that the presence of pVM82 suppressed formation of antibody against some major antigenic determinants of Y. pseudotuberculosis. Immunosuppression took place when the animals were infected with bacteria grown below 20 but not at 37 degrees C. The 57 MD plasmid failed to produce immunosuppression. It was concluded that the 25 MD fragment of pFN82 encoded a novel pathogenic factor responsible for immunosuppression.     

Dendrite‐Free Metallic Lithium in Lithiophilic Carbonized Metal–Organic Frameworks

Although metallic lithium is a promising anode material due to its high theoretical capacity, the uncontrollable growth of lithium dendrites and infinite volume change hamper its practical applications. Here, the lithiophilic property of carbonized metal–organic frameworks (cMOFs) is harnessed with zinc species to achieve a uniform lithium‐cMOFs (Li‐cMOFs) hybrid via a molten lithium infusion approach. In the resultant Li‐cMOFs, not only are abundant Zn clusters are uniformly confined and dispersed in the matrix, serving as homogeneous nucleation sites to guide Li deposition, but also the 3D conductive porous structure enables the homogenization of the distributions of electric field and Li ion flux, avoiding the formation of lithium dendrites. Hence, this hybrid exhibits superior electrochemical performance with a very low voltage hysteresis and a good cycle life. This provides a new manner to achieve a series of stable metallic lithium anodes based on the large family of metal–organic frameworks with tunable metal species.     

Feeding kinematics and morphology of the alligator gar (Atractosteus spatula,Lacépède, 1803)

Living gars are a small clade of seven species that occupy an important position on the actinopterygian phylogenetic tree as members of Holostei, sister-group to teleosts, and exhibit many plesiomorphic traits used to interpret and reconstruct early osteichthyan feeding mechanisms. Previous studies of gar feeding kinematics have focused on the ram-based, lateral-snapping mode of prey capture found in the narrow-snouted Lepisosteus genus, whereas this study focuses on a member of the broad-snouted Atractosteus sister-genus, the alligator gar (Atractosteus spatula, Lacépède, 1803). High-speed videography reveals that the feeding system of alligator gars is capable of rapid expansion from anterior to posterior, timed in a way to generate suction, counteract the effects of a bow-wave during ram-feeding, and direct a unidirectional flow of water through the feeding system. Reconstructed contrast-enhanced μCT-based cranial anatomy and three-dimensional modeling of linkage mechanics show that a lateral-sliding palatoquadrate, flexible intrasuspensorial joint, pivoting interhyal, and retractable pectoral girdle increase the range of motion and expansive capabilities of the alligator gar feeding mechanism. Reconstructions of muscular anatomy, inferences from in vivo kinematics, and in situ manipulations show that input from the hyoid constrictors and hypaxials play an important role in decoupling and modulating the dual roles of the sternohyoideus during feeding: hyoid retraction (jaw opening) and hyoid rotation (pharyngeal expansion). The alligator gar possesses an intricate feeding mechanism, capable of precise control with plesiomorphic muscles that represent one of the many ways the ancestral osteichthyan feeding mechanism has been modified for prey capture.     

The role of repair processes in synergism

Using a simple mathematical model of microorganism inactivation by the combined effect of two agents it was shown that repair processes lead to the synergistic increase of the damage. The latter is due to the additional nonlinearity between the response (inactivation rate constant) and the parameters of the intensity of the damage to the bioobject.     

Red chlorophyll excitation dynamics in Arthrospira platensis photosystem I trimeric complexes as studied by femtosecond transient absorption spectroscopy

Femtosecond absorption spectroscopy was applied to study for the first time excitation dynamics in isolated photosystem I trimers from Arthrospira platensis, which display extremely long-wavelength absorption peaks. Pump–probe spectra observed at 77 K in the timescale of dozens of picoseconds upon 70-fs excitation revealed two maxima near 710 and 730 nm, which correspond to red chlorophyll forms. Bleaching at 680 nm developed in ∼200 fs, whereas the bleaching kinetics at 710 and 730 nm exhibited two components with time constants of 1 and 5.5 ps. Comparison of the kinetics of bleaching development at 710 nm and 730 nm with that of bleaching decay at 680 nm indicated that both long-wavelength forms of trimers are populated mainly via direct energy transfer from bulk chlorophyll.