Germination-specific lipid transfer protein cDNAs in Brassica napus L.

Three cDNA clones encoding lipid transfer proteins (LTPs) were isolated by applying the rapid amplification of cDNA ends (RACE) protocol to imbibed seeds and germinating seedlings Brassica napus. The deduced amino-acid sequences show a great degree of homology and they exhibit the common features shared by all LTPs. Their expression pattern indicates a strong developmental, hormonal, and environmental regulation. They are expressed only in cotyledons and hypocotyls of germinating seedlings and their levels of expression increase upon treatment with cis-abscisic acid and NaCl. Their distribution in the cotyledons of young seedlings is suggestive of a role related to the mobilization of lipid reserves.

Identification of spheroplast-like agents isolated from tissues of patients with Crohn's disease and control tissues by polymerase chain reaction.

Mycobacterium paratuberculosis has been isolated from tissue taken from patients with Crohn's disease and has been implicated in the etiology of this disease. On culture, the organisms appear initially as cell wall-deficient, spheroplast-like forms that are difficult to identify by conventional techniques. Here we examine 30 unidentified cultures by the polymerase chain reaction using primers specific for M. paratuberculosis, Mycobacterium tuberculosis, and Mycobacterium avium restriction fragment length polymorphism type A/I and also by a non-species-specific mycobacterial polymerase chain reaction. Six of these cultures, all from Crohn's disease, were shown to contain DNA from M. paratuberculosis. Cultures from both Crohn's disease and controls were found to contain mycobacterial DNA of unknown specific origin.

Patterns of gene expression in developing anthers of Brassica napus.

The relationship between bud length, anther length and stage of anther development has been investigated in Brassica napus using a series of cytological markers that define steps in the process of male gametogenesis. It was determined that bud length is directly related to anther length and that anther or bud length is tightly linked to the stage of male gametogenesis within the anther. This simple correlation has enabled the construction of cDNA libraries representing transcripts expressed in defined stages of anther development, and the detailed examination of the developmental pattern of expression of anther RNAs. Two anther cDNA libraries were constructed, one from anthers of 1.2-1.8 mm long buds (sporogenesis library) and one from anthers of 1.8-4.0 mm long buds (microspore development library). A total of 19 independent cDNAs have been isolated by differential screening whose temporal expression patterns overlap and which together cover the stages of anther development from pre-meiotic microsporocytes to tri-nucleate pollen grains. The pattern of expression of each of these clones is unique and indicates that stages of anther development which cannot be easily distinguished by light microscopy can be recognised by virtue of the absence or presence of certain RNAs. Three cDNAs isolated from the sporogenesis library have been shown by in situ hybridisation to be tapetum-specific. In contrast, five clones isolated from the microspore development library are microspore-specific. These clones exhibit a pattern of expression different to those previously described in that their transcripts are absent in mature pollen grains. Thus these RNAs are probably required in microspore development rather than for the growth of the germinating pollen grain.