Mapping of A1 conferring resistance to the aphid Amphorophora idaei and dw (dwarfing habit) in red raspberry (Rubus idaeus L.) using AFLP and microsatellite markers

Background  

Raspberry breeding programmes worldwide aim to produce improved cultivars to satisfy market demands and within these programmes there are many targets, including increased fruit quality, yield and season, and improved pest and disease resistance and plant habit. The large raspberry aphid, Amphorophora idaei, transmits four viruses and vector resistance is an objective in raspberry breeding. The development of molecular tools that discriminate between aphid resistance genes from different sources will allow the pyramiding of such genes and the development of raspberry varieties with superior pest resistance. We have raised a red raspberry (Rubus idaeus) F₁ progeny from the cross 'Malling Jewel' × 'Malling Orion' (MJ × MO), which segregates for resistance to biotype 1 of the aphid Amphorophora idaei and for a second phenotypic trait, dwarf habit. These traits are controlled by single genes, denoted (A ₁) and (dw) respectively.     

Responses of the toxic cyanobacterium Microcystis aeruginosa to iron and humic substances.

Iron is an essential element to marine biota. Different types of dissolved organic matter (DOM), such as humic substances have impacts on the marine coastal waters iron chemistry. The aim of the study was to examine how the presence of humic substances (both aquatic and sedimentary) may affect iron bioavailability to the bloom-forming cyanobacterium Microcystis aeruginosa Kutzing incubated on standard and modified mineral BG-11 media. The final iron concentrations in the growth media ranged from 0.1 to 100microM. The results demonstrate that both the growth rate and the concentration of chlorophyll a in cultures of M. aeruginosa are limited by insufficient (<10microM) Fe concentrations. The addition of aquatic humic substances in the presence of iron in concentrations <0.1microM increased the optical density 25-fold, and the production of chlorophyll a 15-fold as compared with the cultures exposed to iron only at the same concentration. Sedimentary humic acids in the presence of iron at a concentration of 10microM reduced the growth and production of chlorophyll a by 50% as compared to the cultures exposed to iron only at the same concentration. Possible mechanisms of humic substances - metal ion - alga interactions are discussed. It is suggested that aquatic humic substances could be of great importance in the formation of cyanobacteria blooms.     

Inhibition of cell division in a moss protonema by some cytokinin isomers

Summary The cytokinin isomers, 1- and 9-isopentenyladenine, are very active inhibitors of cell division in the protonema of the moss Ceratodon purpureus. They also abolish the N⁶-isopentenyladenine-induced stimulation of cell divisions in this material whereas they are inactive on the induction of gametophore buds in moss protonemata by cytokinins.This work was supported by the Polish Academy of Sciences within the project 09.3.1.     

Multiplication-stimulating activity for chicken embryo fibroblasts from rat liver cell conditioned medium: a family of small polypeptides

A partially purified multiplication-stimulating activity for chicken embryo fibroblasts in cell culture was isolated from rat liver cell conditioned medium (see preceding paper, Dulak and Temin, 1973). It has been analyzed by isoelectric focusing and by polyacrylamide gel electrophoresis in sodium dodecyl sulfate. Multiplication-stimulating activity resided in a family of at least four polypeptides which were similar in apparent molecular size, but different in electrical charge. These polypeptides have a specific activity of about 50,000 with respect to serum. One of them has been purified on a small scale to apparent homogeneity in a sodium dodecyl sulfate polyacrylamide gel.     

Research on the ability of propionic acid and vitamin B12 biosynthesis by <Emphasis Type="Italic">Propionibacterium freudenreichii</Emphasis> strain T82

The purpose of this study was to determine the potential for biosynthesis of propionic acid and vitamin B12 by Propionibacterium freudenreichii T82 in a medium containing various sources of carbon (glucose, fructose, and saccharose). These sugars are present in apple pomaces, which are the waste from the production of apple juice. Using statistical analysis design of experiments (DoE), the results allowed us to determine which sugars (carbon sources) exert the most beneficial influence on the biosynthesis of propionic acid and cobalamin. The highest production of propionic acid by the tested bacterial strain was obtained in a medium in which glucose accounted for at least 50% of the available carbon sources. Depending on the culture medium, the concentration of this metabolite ranged from 23 to 40 g/L. P. freudenreichii T82 produced the smallest amount of acid in medium in which the dominant nutrient source was saccharose. The results obtained indicated an inverse relationship between the amount of acid produced by the bacteria and vitamin B12 biosynthesis. Because of the high efficiency of propionic acid biosynthesis by P. freudenreichii T82, the prospect of using this strain to obtain propionate with the simultaneous disposal of waste materials (such as apple pomaces) which contain glucose and/or fructose is very promising.     

Limitation of usage of PicoGreen dye in quantitative assays of double-stranded DNA in the presence of intercalating compounds

PicoGreen is a very sensitive fluorescent dye for quantitative assays of double-stranded DNA (dsDNA) in solution and is used in several analytical protocols in which sensitive and precise DNA detection is needed, also for examination of drug-DNA interactions. The data shown in this paper indicate that compounds intercalating to DNA influence the applicability of PicoGreen dye for quantitative measurements of dsDNA, and for this reason PicoGreen dye is not suitable for examination of drug-DNA interactions, especially interstrand DNA crosslinks.