The simple method of dynamic visco-elastic analysis of road structure. on rheological foundation

In contrast to computationally advanced methods of road pavement dynamic analysis, the one-dimensional, simple method is derived on the basis of visco-elastic simple beam lying on generalized Winkler visco-elastic foundation. By virtue of least square method the visco-elastic constants could be estimated with technically admissible accuracy. The introduced method is useful enough to predict any pavement deformation process in the range of linear visco-elasticity.In contrast to computationally advanced methods of road pavement dynamic analysis, the one-dimensional, simple method is derived on the basis of visco-elastic simple beam lying on generalized Winkler visco-elastic foundation. By virtue of least square method the visco-elastic constants could be estimated with technically admissible accuracy. The introduced method is useful enough to predict any pavement deformation process in the range of linear visco-elasticity

Hanks-Type Serine/Threonine Protein Kinases and Phosphatases in Bacteria: Roles in Signaling and Adaptation to Various Environments

Reversible phosphorylation is a key mechanism that regulates many cellular processes in prokaryotes and eukaryotes. In prokaryotes, signal transduction includes two-component signaling systems, which involve a membrane sensor histidine kinase and a cognate DNA-binding response regulator. Several recent studies indicate that alternative regulatory pathways controlled by Hanks-type serine/threonine kinases (STKs) and serine/threonine phosphatases (STPs) also play an essential role in regulation of many different processes in bacteria, such as growth and cell division, cell wall biosynthesis, sporulation, biofilm formation, stress response, metabolic and developmental processes, as well as interactions (either pathogenic or symbiotic) with higher host organisms. Since these enzymes are not DNA-binding proteins, they exert the regulatory role via post-translational modifications of their protein targets. In this review, we summarize the current knowledge of STKs and STPs, and discuss how these enzymes mediate gene expression in prokaryotes. Many studies indicate that regulatory systems based on Hanks-type STKs and STPs play an essential role in the regulation of various cellular processes, by reversibly phosphorylating many protein targets, among them several regulatory proteins of other signaling cascades. These data show high complexity of bacterial regulatory network, in which the crosstalk between STK/STP signaling enzymes, components of TCSs, and the translational machinery occurs. In this regulation, the STK/STP systems have been proved to play important roles

Occurrence of New Polyenoic Very Long Chain Acyl Residues in Lipids from Acanthamoeba castellanii

The cellular fatty acid composition of Acanthamoeba castellanii, a unicellular bacteriovorous organism, was reinvestigated. Lipids from amoebae grown axenically in proteose peptone-yeast extract-glucose medium were extracted with chloroform–methanol and separated by silicic acid column chromatography into non-polar and polar fractions. The fatty acid composition of the lipids and the double-bond position of the unsaturated acids have been determined by capillary gas chromatography-mass spectrometry (GC-MS) of their corresponding methyl esters, 2-alkenyl-4,4-dimethyloxazoline (DMOX) derivatives and dimethyldisulfide (DMDS) adducts. Evidence is given that lipids from A. castellanii in addition to the three already identified saturated straight chain fatty acids: tetradecanoic (C14:0), hexadecanoic (C16:0), octadecanoic (C18:0), and six preponderant unsaturated fatty acids: hexadecenoic (C16:1 Δ7), octadecenoic (C18:1 Δ9), octadecadienoic (C18:2 Δ9,12), eicosadienoic (C20:2 Δ11,14), eicosatrienoic (C20:3 Δ8,11,14), and eicosatetraenoic (C20:4 Δ5,8,11,14), contain additionally four very long chain unsaturated fatty acids: octacosenoic (C28:1 Δ21), octacosadienoic (C28:2 Δ5,21), triacontadienoic (30:2 Δ21,24), and triacontatrienoic (C30:3 Δ5,21,24) previously unreported in lipids of A. castellanii. These new long chain fatty acids account for approximately 25% of total fatty acids. To our knowledge, this is the first report of very long chain polyenoic fatty acids present in lipids extracted from A. castellanii cells

Endosperm proliferation in a tissue culture: the attempt to induction for Helianthus annuus and the procedure modification for Actinidia deliciosa.

Bielmo jest tkanką, która zapewnia zarodkowi optymalne warunki środowiska, odżywia rozwijający się zarodek i dojrzewające nasiona. Stymulacja bielma do rozwoju daje możliwość uzyskania roślin triploidalnych z roślin diploidalnych. Celem pracy było uzyskanie proliferacji bielma Helianthus annuus. Prowadzono kulturę zalążków na trzech rodzajach pożywek o różnej zawartości regulatorów wzrostu i innych związków organicznych . Część zalążków miała odcięty koniec apikalny, aby uniknąć rozwoju zarodka. W obrazie histologicznym eksplantatów z pożywki A i 0,5 TDZ, obserwowano kilka kulistych struktur przypominających bielmo. Na pożywce AEM bielmo zamierało około 20 dnia kultury. Tkanka bielmowa słonecznika podejmuje rozwój w warunkach kultur in vitro, który przypomina rozwój w warunkach naturalnych.Ponadto podjęta została próba modyfikacji opracowanej już procedury proliferacji izolowanego bielma Actinidia deliciosa. Modyfikacja miała dotyczyć zwiększenia efektywności regeneracji roślin uzyskiwanych z bielma kiwi. Wiązało się to z ustaleniem, który dzień kultury na pożywce AEM (indukującej intensywną proliferację) jest najbardziej odpowiedni do pasażu na pożywkę 0.5 TDZ (indukującą powstawanie pędów przybyszowych). Najefektywniejszy rozwój kalusa występuje po 30 dniach kultury eksplantatów na pożywce AEM i pasażu na pożywkę 0,5 TDZ. Natomiast najwięcej korzeni na kalusie bielma kiwi pojawiło się po 10 dniach na pożywce AEM, i pasażu na pożywkę 0,5 TDZ. Nie obserwowano regeneracji pędów przybyszowych.Endosperm is a tissue that provides the optimum environment for the embryo, nourishes the growing embryo and ripening seeds. Stimulation of endosperm for growth gives an opportunity to obtain triploid plants through diploid plants. The aim of the study was obtain proliferation endosperm of Helianthus annuus. The ovule culture was established on three types of media with different content of growth regulators and other organic compounds. Some of the ovules had an apical fragment with the egg cell and synergids cut off. In the histological sections of explants from medium A and 0,5 TDZ, several spherical structures were observed. On the medium AEM, endosperm died about 20 days of culture. The endosperm development of sunflower under in vitro conditions seems to be similar to the pathway observed in planta.In addition, the try of modification of the proliferation procedure (described earlier) from isolated endosperm of Actinidia deliciosa had been essayed. The aim of modification was to increase the efficiency of regeneration of plant obtained from the endosperm of kiwifruit. It involved finding out which day of culture on medium AEM (inducing intensive proliferation) was most suitable for passage on medium 0,5 TDZ (inducing shoot growth). The most effective callus development occurs after 30 days of culture explants on medium AEM and passage on medium 0,5 TDZ. Whereas, majority roots was observed on endosperm kiwifruit after 10 days on medium AEM and passage on medium 0,5 TDZ. There was no regeneration of adventitious shoots

Structure of antipodal apparatus in embryo sac of Bellis perennis (Asteraceae-Asteroideae)

Komórki antypodalne są najbardziej zmiennym elementem w obrębie woreczka zalążkowego. Celem niniejszej pracy była analiza struktury aparatu antypodalnego u Bellis perennis L. Obserwacje mikroskopowe ujawniły, że liczba antypod w woreczkach zalążkowych stokrotki pospolitej wahała się od 2 do 19 komórek. Antypody były zwykle wielojądrowe, jądra odznaczały się dużymi rozmiarami, nieregularnym kształtem oraz obecnością licznych chromocentrów. Te obserwacje wskazują, że różnicowanie antypod u tego gatunku zachodzi głównie na drodze trzech procesów, tj. wskutek dodatkowych podziałów mitotycznych połączonych z zakładaniem ścian komórkowych, acytokinetycznych podziałów mitotycznych, endomitoz i endoreduplikacji. Antypody u B. perennis są trwałe i zachowują się w gametoficie żeńskim do stadium zarodka globularnego i endospermy komórkowej. W niniejszej pracy stwierdzono występowanie zależności między liczbą antypod a porą sezonu wegetacyjnego. Najliczniejsze kompleksy antypodalne obserwowano w woreczkach zalążkowych kwiatów utrwalonych w maju, podczas gdy w kwiatach utrwalonych w styczniu występowały częste degeneracje komórek antypodalnych lub całych woreczków zalążkowych.Antipodal cells are the most polymorphic element within the embryo sac. The objective of this thesis was an analysis of the antipodal apparatus structure in Bellis perennis L. Microscopic observations revealed that the number of antipodals ranged from 2 to 19 cells. Antipodals were usually multinucleate, their nuclei were large in size, irregular in shape, and characterized by the presence of numerous chromocenters. These observations indicate that three main processes take place during the antipodals’ differentiation in the embryo sacs of B. perennis, e.g. additional mitotic divisions with cytokinesis, acytokinetic mitoses, endomitoses and endoreduplication. In the analyzed embryo sacs, the antipodal cells were persistent and they were visible in the female gametophytes containing a globular embryo and cellular endosperm. In the present investigations, relationship between the number of antiopdals and the time of vegetative season was stated. The most numerous antipodal complexes were observed in the flowers fixed in May, whereas in the flowers fixed in January degeneration of antipodal cells or whole embryo sac occurred frequently

Selection of Endophytic Strains for Enhanced Bacteria-Assisted Phytoremediation of Organic Pollutants Posing a Public Health Hazard

Anthropogenic activities generate a high quantity of organic pollutants, which have an impact on human health and cause adverse environmental effects. Monitoring of many hazardous contaminations is subject to legal regulations, but some substances such as therapeutic agents, personal care products, hormones, and derivatives of common organic compounds are currently not included in these regulations. Classical methods of removal of organic pollutants involve economically challenging processes. In this regard, remediation with biological agents can be an alternative. For in situ decontamination, the plant-based approach called phytoremediation can be used. However, the main disadvantages of this method are the limited accumulation capacity of plants, sensitivity to the action of high concentrations of hazardous pollutants, and no possibility of using pollutants for growth. To overcome these drawbacks and additionally increase the efficiency of the process, an integrated technology of bacteria-assisted phytoremediation is being used recently. For the system to work, it is necessary to properly select partners, especially endophytes for specific plants, based on the knowledge of their metabolic abilities and plant colonization capacity. The best approach that allows broad recognition of all relationships occurring in a complex community of endophytic bacteria and its variability under the influence of various factors can be obtained using culture-independent techniques. However, for practical application, culture-based techniques have priority

Localization of the attachment site of oligoglucans to Mesorhizobium

The location and nature of the linkage between peptidoglycan and oligoglucans in the cell wall of Mesorhizobium loti HAMBI 1148 have been defined by the analysis of nitrous acid deamination of peptidoglycan glucosaminyl residues. The MurN

A Mutation in the <i>Mesorhizobium loti oatB</i> Gene Alters the Physicochemical Properties of the Bacterial Cell Wall and Reduces Survival inside <i>Acanthamoeba castellanii</i>

In our previous report, we had shown that the free-living amoeba Acanthamoeba castellanii influenced the abundance, competiveness, and virulence of Mesorhizobium loti NZP2213, the microsymbiont of agriculturally important plants of the genus Lotus. The molecular basis of this phenomenon; however, had not been explored. In the present study, we demonstrated that oatB, the O-acetyltransferase encoding gene located in the lipopolysaccharide (LPS) synthesis cluster of M. loti, was responsible for maintaining the protective capacity of the bacterial cell envelope, necessary for the bacteria to fight environmental stress and survive inside amoeba cells. Using co-culture assays combined with fluorescence and electron microscopy, we showed that an oatB mutant, unlike the parental strain, was efficiently destroyed after rapid internalization by amoebae. Sensitivity and permeability studies of the oatB mutant, together with topography and nanomechanical investigations with the use of atomic force microscopy (AFM), indicated that the incomplete substitution of lipid A-core moieties with O-polysaccharide (O-PS) residues rendered the mutant more sensitive to hydrophobic compounds. Likewise, the truncated LPS moieties, rather than the lack of O-acetyl groups, made the oatB mutant susceptible to the bactericidal mechanisms (nitrosative stress and the action of lytic enzymes) of A. castellanii

Occurrence of New Polyenoic Very Long Chain Acyl Residues in Lipids from Acanthamoeba castellanii

The cellular fatty acid composition of Acanthamoeba castellanii, a unicellular bacteriovorous organism, was reinvestigated. Lipids from amoebae grown axenically in proteose peptone-yeast extract-glucose medium were extracted with chloroform–methanol and separated by silicic acid column chromatography into non-polar and polar fractions. The fatty acid composition of the lipids and the double-bond position of the unsaturated acids have been determined by capillary gas chromatography-mass spectrometry (GC-MS) of their corresponding methyl esters, 2-alkenyl-4,4-dimethyloxazoline (DMOX) derivatives and dimethyldisulfide (DMDS) adducts. Evidence is given that lipids from A. castellanii in addition to the three already identified saturated straight chain fatty acids: tetradecanoic (C14:0), hexadecanoic (C16:0), octadecanoic (C18:0), and six preponderant unsaturated fatty acids: hexadecenoic (C16:1 Δ7), octadecenoic (C18:1 Δ9), octadecadienoic (C18:2 Δ9,12), eicosadienoic (C20:2 Δ11,14), eicosatrienoic (C20:3 Δ8,11,14), and eicosatetraenoic (C20:4 Δ5,8,11,14), contain additionally four very long chain unsaturated fatty acids: octacosenoic (C28:1 Δ21), octacosadienoic (C28:2 Δ5,21), triacontadienoic (30:2 Δ21,24), and triacontatrienoic (C30:3 Δ5,21,24) previously unreported in lipids of A. castellanii. These new long chain fatty acids account for approximately 25% of total fatty acids. To our knowledge, this is the first report of very long chain polyenoic fatty acids present in lipids extracted from A. castellanii cells