The long and winding road leading to the successful introgression of downy mildew resistance into onion

Downy mildew resistance originating from Allium roylei Stearn provides a complete resistance to onions and is based on one, dominant gene. Since A. roylei can successfully be hybridized with onion (A. cepa L.), a breeding scheme aimed at the introgression of this gene was initiated ca. 20 years ago. Several setbacks in this programme were encountered, firstly the identified molecular marker linked to the downy mildew resistance locus became increasingly difficult to use and finally lost its discriminating power and secondly the final step, making homozygous introgression lines (ILs), turned out to be more difficult then was hoped. GISH analysis showed that the chromosomal region harbouring the resistance locus was the only remaining piece of A. roylei in the nuclear background of onion and it also confirmed that this region was located on the distal end of chromosome 3. It was hypothesized that some factor present in the remaining A. roylei region was lethal when homozygously present in an onion genetic background. The identification of an individual with a smaller and more distally located introgression fragment and homozygous ILs in its progeny validated this hypothesis. With the help of these nearly isogenic lines four AFLP^® markers closely linked to the resistance gene were identified, which can be used for marker-aided selection. The introduction of downy mildew resistance caused by Peronospora destructor into onion is a significant step forward in the development of environmentally-friendly onion cultivars.     

Erhebungsuntersuchung zur Nährstoffversorgung von Picea omorika im Zusammenhang mit dem Omorikensterben

A survey investigation of the relationship between nutritional factors and the decline of Picea omorika growth Soil and needle samples were collected from 193 sites of Picea omorika (mostly in private gardens) in Northern Germany ranging from normal to seriously damaged plants. The needles were analysed for N, P, K, Ca, Mg, Cu, Zn, Mn, Fe, B, Cl and Na. In the soil samples pH, P, K and Mg were determined.

• 1 In 54 cases (= 30,3% of the 178 sites with injured trees) the cause of the damage could not be established. In a few cases only (12 sites = 6,7%) Mg deficiency seemed to have caused the injuries. But in a large number of cases the needles showed high Cl contents, hence Cl toxicity was the most important cause (103 sites = 57,9%) of the damage.
• 2 The critical content of needles sampled in autumn is 0,27 % C1. Above this value CI-toxicity is highly probable and between 0,22 and 0,27 % CI it is possible.
• 3 High Cl-content is associated with mottled chlorosis and in many cases also with a brown discoloration beginning at the tip of the needle. The symptoms are usually stronger at the tips of branches than in central or basal parts.
• 4 Susceptibility to Cl-toxicity is similar for Picea omorika and Picea abies.
• 5 C1-toxicity may be caused by high application of deicing salt and Cl-containing fertilizers. Some of the fertilizers specially developed for the nutrition of conifers even contain too much Cl.

     

A well-preserved Archaeopteryx specimen with theropod features

A nearly complete skeleton of Archaeopteryx with excellent bone preservation shows that the osteology of the urvogel is similar to that of nonavian theropod dinosaurs. The new specimen confirms the presence of a hyperextendible second toe as in dromaeosaurs and troodontids. Archaeopteryx had a plesiomorphic tetraradiate palatine bone and no fully reversed first toe. These observations provide further evidence for the theropod ancestry of birds. In addition, the presence of a hyperextendible second toe blurs the distinction of archaeopterygids from basal deinonychosaurs (troodontids and dromaeosaurs) and challenges the monophyly of Aves.     

Monoclonal antibody-mediated tumor regression by induction of apoptosis

To characterize cell surface molecules involved in control of growth of malignant lymphocytes, monoclonal antibodies were raised against the human B lymphoblast cell line SKW6.4. One monoclonal antibody, anti-APO-1, reacted with a 52-kilodalton antigen (APO-1) on a set of activated human lymphocytes, on malignant human lymphocyte lines, and on some patient-derived leukemic cells. Nanogram quantities of anti-APO-1 completely blocked proliferation of cells bearing APO-1 in vitro in a manner characteristic of a process called programmed cell death or apoptosis. Cell death was preceded by changes in cell morphology and fragmentation of DNA. This process was distinct from antibody- and complement-dependent cell lysis and was mediated by the antibody alone. A single intravenous injection of anti-APO-1 into nu/nu mice carrying a xenotransplant of a human B cell tumor induced regression of this tumor within a few days. Histological thin sections of the regressing tumor showed that anti-APO-1 was able to induce apoptosis in vivo. Thus, induction of apoptosis as a consequence of a signal mediated through cell surface molecules like APO-1 may be a useful therapeutic approach in treatment of malignancy.     

X-ray Absorption Spectroscopic Investigation of Trace Vanadium Sites in Coal

X-ray absorption spectroscopy was used to probe the chemical and structural environment of vanadium in coal. It was found that vanadium exists in at least two environments, in both of which it was coordinated to oxygens. There was no evidence of vanadium in nitrogen (porphyrin) or sulfide environments. It was also found that the vanadium environments in the raw coal did not survive unchanged in a liquefaction process. These findings have implications for coal cleaning processes and for trace element release into the liquefaction process stream.     

Serum alpha globulin fraction: survival-and-recovery effect in irradiated mice

An alpha macroglobulin fraction (19S) was isolated from the serum of rats and BC(3)F(1) mice by zonal ultracentrifugation. Both the isologous and heterologous macroglobulin fractions increased survival among BC(3)F(1) mice x-irradiated with 750 roentgens. The mouse macroglobulin fraction also enhanced radiation recovery of hematopoietic tissue as measured by colony-forming assay and iron-59 incorporation into erythropoietic cells. The overall difference in hematopoietic activity in the irradiated (400 roentgens) mice treated with the macroglobulin fraction, in comparison with this activity in the controls, was three- to fivefold in the bone marrow and nine- to tenfold in the spleen between days 4 and 7 after irradiation. This effect was not obtained with the isologous serum protein fraction containing proteins of smaller molecular weight.     

Atmospheric detection of water dimers via near-infrared absorption

Weakly bonded pairs of water molecules (H2O)2, or water dimers (WDs), may play an important role in photochemistry and climate, but the overlap of most of its spectral features with the water monomer (WM) has made detection difficult. We report on WD absorption measurements by means of atmospheric long-path (18.34 kilometers) differential optical absorption spectroscopy of the near-infrared OH stretching mode 0>f 4>b overtone transition predicted to be located near 746 nanometers. Our observation is in reasonable agreement with the known thermochemistry, calculated and measured structure, and spectroscopy (band strength, shape, and width) of the WD. The observation implies that the WD 0>f 4>b band is located at 749.5 nanometers, with a full width at half maximum of approximately 19.4 wave numbers, and that its band strength ranges between 1.23 x 10(-22) and 5.25 x 10(-22) centimeters per molecule.