Elementary approach to closed billiard trajectories in asymmetric normed spaces

We apply the technique of K\'aroly Bezdek and Daniel Bezdek to study billiard trajectories in convex bodies, when the length is measured with a (possibly asymmetric) norm. We prove a lower bound for the length of the shortest closed billiard trajectory, related to the non-symmetric Mahler problem. With this technique we are able to give short and elementary proofs to some known results.Comment: 10 figures added. The title change

Review: Late stages of protein secretion in bacilli

This review highlights the later stages of protein secretion in bacilli, which include protein release from the membrane and their translocation through the cell wall. Mechanisms of release of secreted polypeptides into the medium differ in Gram-positive and Gram-negative bacteria due to different structure of their cell envelope. Exogenous factors including molecular chaperons that can influence polypeptide folding may be also involved in later stages of protein secretion in bacilli. In Gram-positive bacteria protein secretion also depends on structural components of the cell wall. Certain evidence exists that maintenance of the secretory function is important for normal development of the sporulation process in these bacteria

Cooperative effects in surfactant adsorption layers at water/alkane interfaces

In the present work, the properties of dodecyl dimethyl phosphine oxide (C12DMPO) at the water/decane interface are studied and compared with those obtained earlier at the interface to hexane. To simulate the interfacial behavior, a two-component thermodynamic model is proposed, which combines the equation of state and Frumkin isotherm for decane with the reorientation model involving the intrinsic compressibility for the surfactant. In this approach, the surface activity of decane is governed by its interaction with C12DMPO. The theory predicts the influence of decane on the decrease of the surface tension at a very low surfactant concentration for realistic values of the ratio of the adsorbed amounts of decane and surfactant. The surfactantrsquo;s distribution coefficient between the aqueous and decane phases is determined. Two types of adsorption systems were used: a decane drop immersed into the C12DMPO aqueous solution, and a water drop immersed into the C12DMPO solution in decane. To determine the distribution coefficient, a method based on the analysis of the transfer of C12DMPO between water and decane is also employed

Late stages of protein secretion in bacilli

This review highlights the later stages of protein secretion in bacilli, which include protein release from the membrane and their translocation through the cell wall. Mechanisms of release of secreted polypeptides into the medium differ in Gram-positive and Gram-negative bacteria due to different structure of their cell envelope. Exogenous factors including molecular chaperons that can influence polypeptide folding may be also involved in later stages of protein secretion in bacilli. In Gram-positive bacteria protein secretion also depends on structural components of the cell wall. Certain evidence exists that maintenance of the secretory function is important for normal development of the spomlation process in these bacteria

The cellularlocation of proteolytic enzymes of bacillus intermedium

The activities of proteinases in the culture fluid and cellular fractions of Bacillus intermedius 3-19 grown under various conditions were studied. Thiol-dependent serine proteinase was the prevalent enzyme in the total pool of extracellular proteinases (70%); its catalytically active form was also detected in the cell membrane and, during active enzyme production, in the cell wall. Another enzyme, glutamyl endopeptidase (10% of the total pool), was detected in the cell membrane; it was also found in the cell wall and cytoplasm during active enzyme secretion into the growth medium. Production of these enzymes was maximal on medium containing inorganic phosphate and gelatin and decreased 2- to 4-fold on medium with glucose and lactate. The level of activity of extracellular enzymes correlated with that of corresponding membrane-bound proteins. The addition of CoCl2 (2 mM) into the medium caused an essential increase in extracellular glutamyl endopeptidase activity and promoted the release of the membrane-bound enzyme into the culture fluid. Proteolytic activity towards casein was also detected in the cytoplasm. The proteinases localized in the cytoplasm were shown to differ in their properties from those secreted

Energy-efficient building management via model predictive control

The growing world population and energy consumption, along with the depletion of fossil energy resources and increasing concern regarding the pollution of the environment, make the world-energy problem the largest challenge for technology in the forthcoming decades [1]. Distributed generation could play a major role in the technological changes of the new electricity service paradigm. The use of localized energy sources is only one of the faces of energy management in buildings. A large part of the produced energy is used for heating and cooling systems, in order to maintain acceptable levels of comfort for the occupants of the apartments (hereafter referred to as "users"). Therefore, at a local level, there is a need for the definition and the testing of intelligent algorithms that can automatically manage distributed energy sources, at the same time taking into account the management of heating/ cooling systems

Energy-efficient building management via model predictive control

The growing world population and energy consumption, along with the depletion of fossil energy resources and increasing concern regarding the pollution of the environment, make the world-energy problem the largest challenge for technology in the forthcoming decades [1]. Distributed generation could play a major role in the technological changes of the new electricity service paradigm. The use of localized energy sources is only one of the faces of energy management in buildings. A large part of the produced energy is used for heating and cooling systems, in order to maintain acceptable levels of comfort for the occupants of the apartments (hereafter referred to as "users"). Therefore, at a local level, there is a need for the definition and the testing of intelligent algorithms that can automatically manage distributed energy sources, at the same time taking into account the management of heating/ cooling systems

Genetic mechanisms of bacilli adaptation

Adaptive strategies of bacilli involving genetic regulatory mechanisms are reviewed. The role of master regulators and signal transduction systems that coordinate the interaction of the extracellular signals and the genetic programs responsible for the metabolic state of bacteria are discussed. Most of the known regulatory pathways are directly or indirectly regulated by the DegU, Spo0A, AbrB, and CodY global regulators. The main factor affecting the development of cell phenotype is the concentration of the regulatory protein and its ability to bind with varying affinity to promoters of the genes and operons. The effect of the regulatory systems on the bistability of microbial populations is discussed. © 2013 Pleiades Publishing, Ltd

Microorganisms as phytase producers

Replenishing of the stores of inorganic phosphate is among the most urgent environmental problems. In soil, phosphorus within inorganic compounds is mostly (over 80%) present as insoluble, phytic acid-based conglomerates. Phytates are strong chelating agents, binding the cations of bivalent metals, as well as peptides and low-molecular metabolites into resilient poorly degradable compounds. Their hydrolysis in nature is carried out by microbial phytases, which may potentially be used for an innovative microbial technology. The review deals with microbial degradation of the derivatives of phytic acid. Bacterial species capable of phytase synthesis for stepwise specific cleaving of phytates and their derivatives are discussed. Information analysis was carried out in order to search for the genes encoding phytases in bacterial genomes. Directional modification of the genes of bacterial phytases in order to develop new biotechnologies for agriculture and forage industry is considered. Application of microbial enzymes in agriculture and medicine is analyzed. Bacteria phytases are concluded to have a high practical potential. Microbiology is capable of providing the theoretical and experimental basis for development of the new biotechnology. © 2012 Pleiades Publishing, Ltd

Screening of Heterologous Signal Peptides for Optimization of the LIKE-Expression System

© 2016, Springer Science+Business Media New York.The LIKE-expression system was optimized and used for the production of serine proteinases: subtilisin-like proteinase (AprBp) and glutamyl endopeptidase (GseBp) from Bacillus pumilus. Genes of these enzymes were amplified from genomic DNA of the B. pumilus strain 3-19 and cloned into the LIKE-expression system under the control of the PliaI antibiotic-inducible promoter. Two parameters were investigated to increase the yield of secretory enzymes: heterologous signal peptides from B. megaterium (SPPac, SPYngk) and B. subtilis host strain, which is deficient in two major extracellular proteinases (nprE, aprE). Increased production of GseBp with recombinant SPYngk was achieved after 12 h of growth while increased production of AprBp with its own signal peptide after adding bacitracin was achieved after 20 h of growth. These results suggest that optimized LIKE-expression system can be used for heterologous secretory protein production in B. subtilis