A novel approach to the analysis of the initiation of embryo development in gramineae

An in vivo model system to study the initiation of embryo development is presented. From the so-called Salmon system of wheat (alloplasmic lines with a 1BL-1RS chromosome translocation), three completely isogenic and homozygous lines were produced by selection for uniformity in about 20 selfing/backcross generations as well as between sublines of doubled haploids. The line (aestivum)-Salmon is male fertile and sexual. The lines (caudata)-Salmon and (kotschyi)-Salmon are male sterile and have a parthenogenetic capacity of about 90%. The expression of nuclear-cytoplasmic male sterility is different for the two parthenogenetic lines. The initiation of autonomous embryo development at defined developmental stages of the ovaries and the maximum degree of parthenogenesis are identical in both parthenogenetic lines as proved by the auxin test and progeny analyses. The protein patterns from ovary extracts of the three isogenic lines were identical for more than 200 spots of 2-D polyacrylamide gels, confirming their homogeneity. However, one protein (P 115.1) was found 3 days before and during anthesis only in ovaries of the parthenogenetic lines. It seems to be involved in the initiation of parthenogenesis.     

Thermophilic Bacilli growing with carbon monoxide

Four strains of obligately thermophilic Bacilli capable of growing with carbon monoxide as a sole carbon and energy source were isolated from settling ponds of a sugar factory. Most of them could be identified as strains of Bacillus schlegelii on the basis of cell wall composition, DNA homology menaquinone and DNA base content. Growth with CO was very fast (t _d =3 h) and was optimal at 65°C. No growth occurred below 50°C. As with the mesophilic carboxydotrophs, hydrogen plus carbon dioxide could also serve as autotrophic substrates. Growth of the isolates with CO depended on the presence of molybdenum in the growth medium. This suggested CO oxidase in the newly isolated Bacilli being a molybdenum hydroxylase similar to the enzymes from the mesophilic carboxydotrophs. Some data characterizing the CO-oxidizing activity in extracts of the thermophilic isolates are also provided.This paper is respectively dedicated to Professor Dr. H. G. Schlegel on the occasion of his 60th birthday     

Carbonized food plants of Pompeii,Herculaneum, and the Villa at Torre Annunziata

The remains of carbonized plants recovered from sites destroyed by Mount Vesuvius in A.D. 79 furnish valuable historical evidence on many staple food plants used by the ancient Campanians of the 1st century A.D. Carbonized seeds,grains, nuts, and fruits of 24 species identified from documented materials at Pompeii, Herculaneum, and the Roman villa at Torre Annunziata include: filbert, Corylus avellana;broadbean, Vicia fabavar. minor;bittervetch. Vicia ervilia;chickpea, Cicer arietinum;carob, Ceratonia siliqua;lentil, Lens culinaris;European chestnut, Castanea sativa;English or Persian walnut, Juglans regia;common onion, Allium cepa;garlic, Allium sativum;fig, Ficus carica;olive, Olea europaea;date, Phoenix dactylifera;stone pine, Pinus pinea;six-rowed barley, Hordeum vulgare;emmer wheat, Triticum dicoccon;common millet, Panicum miliaceum;Italian millet, Setaria italica;oat, Avena sativa;almond, Prunus dulcis;sour cherry, Prunus cerasus;pear, Pyrus communis;crabapple, Malussp.;and grape, Vitis vinifera.     

Fluid transport in a thick layer above an active ciliated surface.

The discrete cilia approach is employed to describe the flow field above an active ciliated surface in a layer of finite depth. The infinite-size cilia surface model predicts a uniform flow above the cilia surface. Modifications as a result of a finitely extending cilia surface inside a finite-size dish predict a backward parabolic profile above an active cilia surface. Experiments are described which demonstrate a good fit between theoretical predictions and observations. The results provide a sound physical basis for the proper interpretation of fluid-flow observations close to an active ciliary field.     

Dielectric behavior of linear polyelectrolytes

The dipolar correlation function for a system of counterions diffusing on the surface of a polyelectrolyte cylinder is computed. Repulsive coulombic interactions between the counterions are taken into account. Lateral dissociation and reassociation to the cylinder is treated microscopically. Numerical calculations needed to obtain quantitative results for the long time behavior are presented. The model dependence on its parameters is interpreted with special emphasis on parameter values typical of DNA.