Age and changes in succinate dehydrogenase activity in functionally different muscles of the young rat

The antigravitational m. triceps brachii, its antagonist m. brachialis and the muscle having a universal functional specialization--m. serratus ventralis--have been studied in 35 male rats of Wistar strain, 60-105-day-old. Succinate dehydrogenase activity is determined in muscle fibers. Changes in the muscle fibers continue after the rats reach their sex maturation. Certain stageness of the process is observed, but the division of the period into separate steps either is absent (m. brachials), or their number is not great as compared to those during the 1st--60th days after birth. The borders of the periods in the muscles studied coinside (the 70th--74th day). Although it is possible to reveal the periods and separate steps in the changes occurring in the muscle fibers and in the muscles of the animals having reached their sex maturation, nevertheless, the borders between them are not distinct, the reconstruction during this age proceeds slower and more smoothely than before the sex maturation. It is possible that in young rats after sex maturation differentiation of the muscle fibers continues and that, in its turn, stimulates further specialization of the muscles as organs. The changes in the muscle fibers revealed histochemically occur most slowly under a low static loading, and when loading of various modality (kinetic and static) are combined, they are mostly pronounced.     

TDZ-induced axillary shoot proliferation of Rhododendron mucronulatum Turcz and assessment of clonal fidelity using DNA-based markers and flow cytometry

In Vitro Cellular & Developmental Biology - Plant - In order to induce in vitro axillary shoot proliferation from single-node explants of Rhododendron mucronulatum Turcz., two techniques of...     

Role of Lipopolysaccharide and Nonspecific Porins of Yersinia pseudotuberculosis in the Reception of Pseudotuberculous Diagnostic Bacteriophage

Applied Biochemistry and Microbiology - The role of the outer membrane components of Yersinia pseudotuberculosis and Yersinia pestis in the adsorption of pseudotuberculous diagnostic bacteriophage...     

Activation of acid growth in germinating horse chestnut seeds

The validity of the acid-growth hypothesis is proved for the case of cell elongation initiation in germinating seeds of horse chestnut (Aesculus hippocastanum L.), the embryo axes of which are known to extend during the first stages of germination only by cell elongation. During seed imbibition, H⁺-ion excretion was firstly low; it increased several times prior to radicle emergence and was maintained at a high level during growth initiation and further cell elongation. Cell wall acidification and radicle emergence were enhanced in the presence of 0.02 mM fusicoccin, thus indicating the involvement of the plasma membrane H⁺-ATPase in the execution of acid growth. The presence of this enzyme and its activator (14-3-3 protein) in microsomal fractions obtained from radicles and hypocotyls of the embryo axes during and after initiation of cell elongation was demonstrated immunochemically. It is supposed that the initiation of cell elongation at early germination occurs via the activation of the plasma membrane H⁺-ATPase and results in the acidification of cell walls, leading to their higher extensibility, in accordance with the hypothesis of acid growth.     

An Artificial Neural Network Model to Predict the Phenology of Early-Maturing Soybean Varieties from Climatic Factors

Biophysics - Abstract—Soybean phenology is strongly influenced by temperature and day length, and phenological records clearly reflect the changes in climatic conditions. A model including...     

Stress-protective and cross action of the extracellular reactivating factor of the microorganisms of the domains Bacteria, Archaea, and Eukaryota

Cross protection of members of the domains Bacteria, Archaea, and lower Eukaryota from stress factors due to the action of extracellular low-molecular metabolites with adaptogenic functions was shown. The adaptogen produced by Luteococcus japonicus subsp. casei and described previously as a reactivating factor (RF) was shown to protect the yeasts Saccharomyces cerevisiae, archaea Haloarcula marismorti, and the cells of higher eukaryotes (HeLa) against weak stressor impacts. Production of an archaeal extracellular metabolite with a weak adaptogenic effect of the producer cells and capable of a threefold increase in survival of heat-inactivated yeast cells was discovered. Our results confirm the similarity of the compensatory adaptive reactions in prokaryotes (bacteria and archaea) and eukaryotes.     

OmpC-like porin from outer membrane of Yersinia enterocolitica: Molecular structure and functional activity

OmpC-like porin was isolated from the outer membrane (OM) of Yersinia enterocolitica cultured at 37°C (the “warm” variant) and its physicochemical and functional properties were studied. The amino acid sequence of OmpC porin was established, and the primary structure and transmembrane topology of this protein were analyzed in comparison with the OmpF porin isolated from Y. enterocolitica cultured at 6°C (the “cold” variant). Both porins of Y. enterocolitica had a high homology degree (65%) between themselves and with OmpC and OmpF porins from OM of Escherichia coli (58 and 76% homology, respectively). The secondary structure of OmpC and OmpF porins from OM of Y. enterocolitica consists of 16 β-strands connected by short “periplasmic” and longer “extracellular” loops with disordered structure, according to the topological model developed for porins of E. coli. The molecular structures of OmpC and OmpF porins of Y. enterocolitica have significant differences in the structure of the “extracellular” loops and in the position of one of three tryptophan residues. Using the bilayer lipid membrane (BLM) technique, pores formed by OmpC porin of Y. enterocolitica were shown to differ in electrophysiological characteristics from channels of OmpF protein of this microorganism. The isolated OmpC porin reconstructed into BLM displayed functional plasticity similarly to OmpF protein and nonspecific porins of other enterobacteria. The conductivity level of the channels formed by this protein in the BLM was regulated by value of the applied potential.