The pea early nodulin gene PsENOD7 maps in the region of linkage group I containing sym2 and leghaemoglobin

The early nodulin gene, PsENOD7, is expressed in pea root nodules induced by Rhizobium leguminosarum bv. viciae, but not in other plant organs. In situ hybridization showed that this gene is transcribed during nodule maturation in the infected cells of the proximal part of the prefixation zone II. At the transition of zone II into interzone II–III, the level of PsENOD7 mRNA drops markedly. PsENOD7 has no significant homology to other genes. RFLP mapping studies have shown that PsENOD7 is located in linkage group I between the leghaemoglobin genes and sym2.     

Comparison of soybean and pea ENOD40 cDNA clones representing genes expressed during both early and late stages of nodule development

A pea cDNA clone representing the homologue of the soybean pGmENOD40-1 was isolated and characterized. At the nucleotide level both clones share 55% homology. Strikingly, the homology between the polypeptides derived from the pea and soybean ENOD40 cDNA sequences is only 14%. Despite this low homology Southern analyses revealed that the isolated pea cDNA clone represents the single pea ENOD40. In situ hybridizations showed that at early stages of nodule development and in mature nodules the expression pattern of pea ENOD40 is comparable to that of soybean ENOD40. Although ENOD40 show similar expression patterns in these two nodules, it is questionable whether the putative polypeptides have a similar function, since the homology is very low.     

Construction of a hybrid col E1 plasmid carrying the gene for bacteriophage lambda repressor.

A biologically active hybrid DNA molecule was constructed from plasmid Col E1 and the Eco R1 fragment of lambda DNA containing the gene for lambda repressor. The presence of this gene in the hybrid molecule was demonstrated genetically. The hybrid plasmid contains two closely located targets for restriction endonuclease Hind 111 in the integrated fragment. Thus, the plasmid may be used as a vector not only for Eco R1 fragments but also for Hind 111 fragments.     

R.SspD5I is a neoschizomer of HphI producing blunt end DNA fragments

The strain Staphylococcus species D5 produces a restriction enzyme. It is the neoschizomer of HphI endonuclease, which cleaves DNA at a distance of eight nucleotides from the recognition sequences producing blunt end DNA fragments: 5'-GGTGA8N /-3' and 3'-CCACT8N /-5'.     

Remote Probing of Plant Photosynthetic Apparatus by Measuring Laser-Induced Fluorescence

Laser-induced fluorescence of birch, pine, and aspen trees was studied. The fluorescence of birch leaves, excited with a Xe–Cl laser at a wavelength of 308 nm, was measured under laboratory conditions. A persistent directly proportional dependence was found between the measured fluorescence signals and the chlorophyll content. An apparatus for measuring laser-induced fluorescence under field conditions was designed. Deciduous trees were found to have a wider range of fluorescence variability when compared to conifers, with the fluorescence intensity increasing in the leaves of deciduous trees before the autumn fall of leaves, during leaf yellowing. It is concluded that the method of lidar probing can be used for identifying tree species and assessing the condition of leaf and needle canopies.