Lectin-gene expression in pea (Pisum sativum L.) roots

The expression of a lectin gene in pea (Pisum sativum L.) roots has been investigated using the copy DNA of a pea seed lectin as a probe. An mRNA which has the same size as the seed mRNA but which is about 4000 times less abundant has been detected in 21-d-old roots. The probe detected lectin expression as early as 4 d after sowing, with the highest level being reached at 10 d, i.e. just before nodulation. In later stages (16-d- and 21-d-old roots), expression was substantially decreased. The correlation between infection by Rhizobium leguminosarum and lectin expression in pea roots has been investigated by comparing root lectin mRNA levels in inoculated plants and in plants grown under conditions preventing nodulation. Neither growth in a nitrate concentration which inhibited nodulation nor growth in the absence of Rhizobium appreciably affected lectin expression in roots.Abbreviation cDNA copy DNA - poly(A)⁺RNA polyadenylated RNA     

Should colonoscopy be the first investigation for colonic disease?

Many patients with suspected colonic disease undergo rigid sigmoidoscopy, barium enema examination, and ultimately total colonoscopy, but the need for preliminary radiology has not been formally assessed. A total of 168 patients requiring large bowel investigation were therefore randomised to undergo either rigid sigmoidoscopy plus double contrast barium enema examination or total colonoscopy. Disease was found in 56 patients, including 14 with a carcinoma, 11 with polyps, and 16 with inflammatory bowel disease, the remainder having diverticular disease alone. Of the 89 patients allocated to double contrast barium enema examination, nine required a subsequent colonoscopy for suspected tumour or polyps, three because of incomplete radiological examination, and 12 for rectal bleeding for which no cause was found at the radiological examination. In 16 patients this yielded further information or altered treatment. Of the 79 patients undergoing total colonoscopy, only six required subsequent radiology.As both procedures were well tolerated with no major complications total colonoscopy may be the preferred initial investigation where facilities allow.     

Assignment of the gene encoding the catalytic subunit Cβ of CAMP-dependent protein kinase to the p36 band on chromosome

Summary A cDNA for the human catalytic subunit (C) of cAMP-dependent protein kinase (PKA) has been cloned from a testis cDNA library. In the present study, we have determined the chromosomal localization of this gene using a cDNA for C as a probe. Southern blot analysis of genomic DNA from human/mouse cell hybrids revealed that the presence or absence of a 20-kbXbaI fragment, which hybridized with the C probe, was concordant with the presence of human chromosome 1.In situ hybridization to metaphase chromosome confirmed the somatic cell hybrid data and regionally mapped the C gene of PKA to the p36 band on chromosome 1.     

New chromosome 21 DNA markers isolated by pulsed field gel electrophoresis from an ETS2-containing Down syndrome chromosomal region

To generate new chromosome 21 markers in a region that is critical for the pathogenesis of Down syndrome (D21S55-MX1), we used pulsed field gel electrophoresis (PFGE) to isolate a 600-kb NruI DNA fragment from the WA17 hybrid cell line, which has retained chromosome 21 as the only human material. This fragment, which contains the oncogene ETS2, was used to construct a partial genomic library. Among the 14 unique sequences that were isolated, 3 were polymorphic markers and contained sequences that are conserved in mammals. Five of these markers mapped on the ETS2-containing NruI fragment and allowed us to define an 800-kb high-resolution PFGE map.     

Preparative resolution of some 5,5-hydantoin derivatives via formation of diastereoisomeric salts

Several preparative resolutions of 5,5-disubstituted hydantoins have been achieved via fractional crystallization of diastereoisomeric salts. The process can be extended by making use of the difference between the variation of solubilities of the hydantoins and their salts with α-methylbenzylamine as a function of the alkalinity of the medium. Optimization for each resolution procedure involves a refinement of the excess amount of base needed. © 1992 Wiley-Liss, Inc.     

Differential accumulation of hydroxyproline-rich glycoproteins in bean root nodule cells infected with a wild-type strain or a C4-dicarboxylic acid mutant of Rhizobium leguminosarum bv. phaseoli

An antiserum raised against deglycosylated hydroxyproline-rich glycoproteins (HPGPs) from melon (Cucumis melo L.) was used to study the relationship between Rhizobium infection and induction of HRGPs in bean (Phaseolus vulgaris L.) root nodule cells infected with either the wild-type or a C₄-dicarboxylic acid mutant strain of Rhizobium leguminosarum bv. phaseoli. In effective nodules, where fixation of atmospheric dinitrogen is taking place, HRGPs were found to accumulate mainly in the walls of infected cells and in peribacteroid membranes surrounding groups of bacteroids. Internal ramifications of the peribacteroid membrane were also enriched in HRGPs whereas the peribacteroid space as well as the bacteroids themselves were free of these glycoproteins. In mutant-induced root nodules, HRGPs were specifically associated with the electron-dense, laminated structures formed in plastids as a reaction to infection by this mutant. The presence of HRGPs was also detected in the host cytoplasm. The aberrant distribution of HRGPs in infected cells of mutant-induced nodules likely reflects one aspect of the altered host metabolism in relation to peribacteroid-membrane breakdown. The possibility that the antiserum used for HRGP localization may have cross-reacted with ENOD 2 gene products is discussed in relation to amino-acid sequences and sites of accumulation.