Impacts of chemical gradients on microbial community structure

Succession of redox processes is sometimes assumed to define a basic microbial community structure for ecosystems with oxygen gradients. In this paradigm, aerobic respiration, denitrification, fermentation and sulfate reduction proceed in a thermodynamically determined order, known as the ‘redox tower’. Here, we investigated whether redox sorting of microbial processes explains microbial community structure at low-oxygen concentrations. We subjected a diverse microbial community sampled from a coastal marine sediment to 100 days of tidal cycling in a laboratory chemostat. Oxygen gradients (both in space and time) led to the assembly of a microbial community dominated by populations that each performed aerobic and anaerobic metabolism in parallel. This was shown by metagenomics, transcriptomics, proteomics and stable isotope incubations. Effective oxygen consumption combined with the formation of microaggregates sustained the activity of oxygen-sensitive anaerobic enzymes, leading to braiding of unsorted redox processes, within and between populations. Analyses of available metagenomic data sets indicated that the same ecological strategies might also be successful in some natural ecosystems

Rice actin binding protein RMD controls crown root angle in response to external phosphate

Root angle has a major impact on acquisition of nutrients like phosphate that accumulate in topsoil and in many species; low phosphate induces shallower root growth as an adaptive response. Identifying genes and mechanisms controlling root angle is therefore of paramount importance to plant breeding. Here we show that the actin-binding protein Rice Morphology Determinant (RMD) controls root growth angle by linking actin filaments and gravity-sensing organelles termed statoliths. RMD is upregulated in response to low external phosphate and mutants lacking of RMD have steeper crown root growth angles that are unresponsive to phosphate levels. RMD protein localizes to the surface of statoliths, and rmd mutants exhibit faster gravitropic response owing to more rapid statoliths movement. We conclude that adaptive changes to root angle in response to external phosphate availability are RMD dependent, providing a potential target for breeders

Arbeitsorientierte Gestaltung von Informationsprozessen

The work-oriented formation of information processes embraces the shaping of the system of work in which new technologies are or should be applied, and also that of the preparatory and introductory process itself. The authors present concepts and criteria for the shaping of systems of work, which apply to such systems in general, and software houses in particular. Task orientation and the concept of `total activity' play a central part. Questions of man/machine functional division remain to be answered before work-shaping by software engineering can be extended significantly. On the basis of these general concepts and shaping criteria, a structure and a compatible process organisation for software preparation are presented and discusse

Gravity Sensing, Graviorientation and Microgravity

Gravity has constantly governed the evolution of life on Earth over the last 3.5 billion years while the magnetic field of the Earth has fluctuated over the eons, temperatures constantly change, and the light intensity undergoes seasonal and daily cycles. All forms of life are permanently exposed to gravity and it can be assumed that almost all organisms have developed sensors and respond in one way or the other to the unidirectional acceleration force. Here we summarize what is currently known about gravity sensing and response mechanisms in microorganisms, lower and higher plants starting from the historical eye-opening experiments from the nineteenth century up to today’s extremely rapidly advancing cellular, molecular and biotechnological research. In addition to high-tech methods, in particular experimentation in the microgravity environment of parabolic flights and in the low Earth orbit as well as in “microgravity simulators” have considerably improved our knowledge of the fascinating sensing and response mechanisms which enable organisms to explore and exploit the environment on, above and below the surface of the Earth and which was fundamental for evolution of life on Earth

Soybean genetic transformation: a valuable tool for the functional study of genes and the production of agronomically improved plants

Transgenic plants represent an invaluable tool for molecular, genetic, biochemical and physiological studies by gene overexpression or silencing, transposon-based mutagenesis, protein sub-cellular localization and/or promoter characterization as well as a breakthrough for breeding programs, allowing the production of novel and genetically diverse genotypes. However, the stable transformation of soybean cannot yet be considered to be routine because it depends on the ability to combine efficient transformation and regeneration techniques. Two methods have been used with relative success to produce completely and stably transformed plants: particle bombardment and the Agrobacterium tumefaciens system. In addition, transformation by Agrobacterium rhizogenes has been used as a powerful tool for functional studies. Most available information on gene function is based on heterologous expression systems. However, as the activity of many promoters or proteins frequently depends on specific interactions that only occur in homologous backgrounds, a final confirmation based on a homologous expression system is desirable. With respect to soybean biotech improvement, transgenic lines with agronomical, nutritional and pharmaceutical traits have been obtained, including herbicide-tolerant soybeans, which represented the principal biotech crop in 2011, occupying 47% of the global biotech area