Individual optimization: Mechanisms shaping the optimal reaction norm

In general, optimal reaction norms in heterogeneous populations can be obtained only by iterative numerical procedures (McNamara, 1991; Kawecki and Stearns, 1993). We consider two particular, but biologically plausible and analytically tractable cases of individual optimization to gain insight into the mechanisms which shape the optimal reaction norm of fecundity in relation to an environmental variable or an individual trait. In the first case, we assume that the quality of the environment (e.g. food abundance) or the quality of the individual (e.g. body size) is fixed during its entire life; it may also be a heritable individual trait. In the second case, individual quality is assumed to change randomly such that the probability distribution of quality in the next year is the same for the parent and for her offspring. For these two cases, we obtain analytical expressions for the shape of the optimal reaction norm, which are heuristically interpretable in terms of underlying selective mechanisms. It is shown that better quality may reduce the optimal fecundity. This outcome is particularly likely if better quality increases a fecundity-independent factor of parental survival in a long-lived species with fixed quality. This revised version was published online in July 2006 with corrections to the Cover Date.     

Methylobacterium extorquens strain P14, a new methylotrophic bacteria producing poly-beta-hydroxybutyrate (PHB).

Strain P14 of facultative methylotrophic bacteria that synthetisizes poly-beta-hydroxybutyrate has been isolated. The cells are gram-negative motile rods with a polar flagellum. They do not form spores or capsules, but do have a caretenoid pigment. Predominant in the fatty acid composition of the cells is cis-vaccenic acid (cis 18:1: omega 7)--72%. In the phospholipid composition phosphatidylcholine predominates (45%), along with phosphatidylenthanoloamine (27%) and phosphatidylglycerol (17%). The main biquinone is Q-10; other ubiquinones (Q-8, Q-9, Q-11) are present in minor quantities. The cells accomplish the icl-variant of serine pathway. The GC content of DNA (Tm) is 65 mole%. A high level DNA-DNA homology with representatives of the genus Methylobacterium was observed. The strain has been identified as Methylobacterium extorquens strain P14.     

DNA Recognition by Non-Natural Oligonucleotides

Abstract

Non-natural oligonucleotides were synthesized by modified phosphoramidite procedure and tested in triple helix-mediated DNA recognition.     

The Effect of Aerobic Methylotrophic Bacteria on the in vitro Morphogenesis of Soft Wheat (Triticum aestivum)

The effects of four aerobic methylotrophic bacteria on the morphogenesis of soft wheat (Triticum aestivum) were studied in vitro using immature embryos as explants. The inoculation of the embryos with methylotrophic bacteria led to their stable colonization with the bacteria. The colonization of the explants with the strains of Methylobacterium sp. D10 and Methylophilus glucoseoxidans stimulated the formation of morphogenic calli and shoots and also promoted development of the regenerated plants. These regenerated plants manifested bright green leaves and a well-developed root system. The colonization of immature wheat embryos with methylotrophic bacteria can be employed as a tool for raising the efficiency of genetic transformation of various wheat cultivars.     

Degradation of the EDTA and EDTA complexes with metals by immobilized cells of Chelativorans oligotrophicus LPM-4 bacteria

Enzymatic oxidative degradation of EDTA and EDTA complexes with metals has been investigated using immobilized cells of Chelativorans oligotrophicus LPM-4. A polarographic method, which makes it possible to register oxygen consumption by cells, has been used. For the first time, it has been indicated that the Cd-EDTA and Ni-EDTA complexes undergo degradation by the bacteria under study.     

Structural and Functional Features of the Wheat Embryo Sac’s Antipodal Cells during Differentiation

Russian Journal of Developmental Biology - A detailed study into the structural features of the multilevel antipodal complex of wheat Triticum aestivum L. embryo sac was performed at different...     

Biotechnological Potential of Aerobic Methylotrophic Bacteria: A Review of Current State and Future Prospects

Major results of the authors' findings on the implementation of the biotechnological potential of aerobic methylobacteria and methanotrophs for obtaining forage proteins, biopolymers (polybutyrate and polysaccharides), enzymes (oxidoreductases), and bioprotectors (ectoine), as well as for degrading toxic C₁ and C_n compounds, have been reviewed. Unique features of the structural and functional organization of the metabolism of extremophilic (tolerant) methylotrophs are discussed, with a view for their prospective use in various fields of modern biotechnology, including biocatalysis and nanotechnology.