Y3IP1, A nucleus-encoded Thylakoid Protein, Cooperates with the Plastid-Encoded YCf3 Protein in Photosystem I Assembly of Tobacco and Arabidopsis

The intricate assembly of photosystem I (PSI), a large multiprotein complex in the thylakoid membrane, depends on auxiliary protein factors. One of the essential assembly factors for PSI is encoded by ycf3 (hypothetical chloroplast reading frame number 3) in the chloroplast genome of algae and higher plants. To identify novel factors involved in PSI assembly, we constructed an epitope-tagged version of ycf3 from tobacco (Nicotiana tabacum) and introduced it into the tobacco chloroplast genome by genetic transformation. Immunoaffinity purification of Ycf3 complexes from the transplastomic plants identified a novel nucleus-encoded thylakoid protein, Y3IP1 (for Ycf3-interacting protein 1), that specifically interacts with the Ycf3 protein. Subsequent reverse genetics analysis of Y3IP1 function in tobacco and Arabidopsis thaliana revealed that knockdown of Y3IP1 leads to a specific deficiency in PSI but does not result in loss of Ycf3. Our data indicate that Y3IP1 represents a novel factor for PSI biogenesis that cooperates with the plastid genome-encoded Ycf3 in the assembly of stable PSI units in the thylakoid membrane

The Economy of Dürrnberg-Bei-Hallein: An Iron Age Salt-mining Centre in the Austrian Alps

For the first time in English, we present a summary of the international programme of excavation work carried out between 1990 and 2001 in and around the Iron Age salt-mining complex of the Diirrnberg region, south of Salzburg. First we describe the results of excavation in the prehistoric adits, and of work to locate and survey associated settlements. This is followed by a series of specialist reports embracing floral and faunal remains, palaeodiet and parasitology, leather and woodworking and other crafts. The evidence suggests that a complex inter-relationship existed between the Diirrnberg and other communities in the Alpine foreland. It is assumed that the Diirrnberg was under the control of an elite - perhaps a local dynasty whose wealth is reflected in the grave

The Human Cell Atlas.

The recent advent of methods for high-throughput single-cell molecular profiling has catalyzed a growing sense in the scientific community that the time is ripe to complete the 150-year-old effort to identify all cell types in the human body. The Human Cell Atlas Project is an international collaborative effort that aims to define all human cell types in terms of distinctive molecular profiles (such as gene expression profiles) and to connect this information with classical cellular descriptions (such as location and morphology). An open comprehensive reference map of the molecular state of cells in healthy human tissues would propel the systematic study of physiological states, developmental trajectories, regulatory circuitry and interactions of cells, and also provide a framework for understanding cellular dysregulation in human disease. Here we describe the idea, its potential utility, early proofs-of-concept, and some design considerations for the Human Cell Atlas, including a commitment to open data, code, and community

The Gα Protein Controls a pH-Dependent Signal Path to the Induction of Phytoalexin Biosynthesis in Eschscholzia californica

The function of a Gα protein in the elicitation of phytoalexin (benzophenanthridine) biosynthesis was characterized in cultured cells of California poppy (Eschscholzia californica). Both the decrease of Gα content via antisense transformation and the expression of recombinant anti-Gα single-chain antibodies strongly impaired the induction of alkaloid biosynthesis by low elicitor concentrations. All transgenic cell types were deficient in two elicitor-triggered early signal events: activation of phospholipase A(2) (PLA(2)) and efflux of vacuolar protons. The lacking H(+) efflux could be restored (1) by adding lysophosphatidylcholine (LPC), a product of PLA(2) activity, to vacuoles in situ and (2) by exposing intact cells to isotonic, near-neutral HEPES buffers. The latter treatment induced alkaloid biosynthesis in the absence of elicitor and in Gα-deficient cells. We conclude that Gα mediates the stimulation of PLA(2) by low elicitor concentrations and that the resulting peak of LPC initiates a transient efflux of vacuolar protons. In this way, an acidic peak of the cytoplasmic pH is generated that causes the expression of enzymes of phytoalexin production independent of the hypersensitive response

Tabular ground ice origin: cryolithological and isotope-geochemical study

An integrated cryolithological-isotope-geochemical study was undertaken at five sites in the Arctic within the framework of a three-year INTAS project. The conclusion based on geochemical analyses is that at the Asian westernmost Yugorsky to the easternmost Chukotka, marine sedimentation changed to subaerial followed by permafrost and massive ice formation due to the regression of the polar basin. Burial of the surface ice was possible, mainly in the mountainous areas of the Arctic coasts, i.e. the Urals and Chukotka