Molecular markers for seed colour in Brassica juncea.

A detailed RFLP map was used to map QTLs associated with seed colour in Brassica juncea using a doubled-haploid population derived from a cross between a black/brown-seeded cultivar and a yellow-seeded breeding line. Segregation analysis suggested that seed colour was under control of 2 unlinked loci with duplicate gene action. However, QTL analysis revealed 3 QTLs, SC-B4, SC-A10 and SC-A6, affecting seed colour. The QTLs were consistent across environments, and individually explained 43%, 31%, and 16%, respectively, and collectively 62% of the phenotypic variation in the population. Digenic interaction analysis showed that closest flanking locus of QTL SC-B4, wg7b6cNM, had strong epistasis with the locus wg5a1a, which is tightly linked to QTL SC-A6. The interaction of these 2 loci explained 27% of the phenotypic variation in the population, while the whole model explained 84%. In a multiple regression model, the effects of QTL SC-A10, as well as its interaction with other loci, were non-significant, whereas the effects of loci wg7b6cNM and wg5a1a and their interaction were significant. Ninety-eight percent of the DH lines carried the expected alleles of loci wg7b6cNM and wg5a1a for seed colour, confirming that only these 2 loci were linked to seed colour in B. juncea. Four additional digenic interactions significantly affected seed colour, and all 5 digenic interactions were consistent across environments.

The use of an Ommaya reservoir for administration of morphine sulphate to control pain in select cancer patients.

The Ommaya reservoir is an implantable device which allows percutaneous intraventricular administration of preservative-free morphine sulfate. Use of this device in select cancer patients has worked well in providing pain control when conventional methods have failed. Using an Ommaya reservoir is not without complications, and patients may experience side effects of morphine, but most of these effects can be controlled. Teaching begins early so the patient can be discharged with a dose and schedule which provide pain control, and the responsible family member can be proficient in administration. Home care and follow-up are necessary to assure pain control and absence of complications.

The development of a microimmunoadsorbent assay and a microdialysis method for the evaluation of immunoadsorbent efficiency and antibody quantitation.

A microimmunoadsorbent assay which provides for the quantitative elution and recovery of active antibody from immunoaffinity columns has been developed. We have also designed a microdialysis chamber which permits the dialysis of sample volumes from 50 to 500 microliters and allows quantitative recovery of macromolecular compounds. These techniques permit the rapid evaluation of a large number of eluants and immunoadsorbents in a short period of time. The microimmunoadsorbent assay coupled with the microdialysis method has been used to evaluate the efficacy of different anti-isopentenyl adenosine immunoadsorbents under various elution conditions. In the present study the best eluants for immunoaffinity purification of anti-N6-(delta 2-isopentenyl)adenosine antibody contained 15% pyridine in a sodium phosphate buffer or 4 M imidazole-HCl at pH 10.0.

Investigation of immunoadsorbent efficiency and capacity for the isolation of tRNAs containing N6-(delta 2-isopentenyl)adenosine derivatives.

Antibodies directed to modified nucleosides recognize the nucleoside (antigen) when it is present in an intact tRNA molecule. The general application of anti-nucleoside immunoadsorbent chromatography, however, has been greatly impeded by the apparent inefficiency and low capacity of conventional immunoadsorbents for transfer RNA. Antibodies specific for isopentenyladenosine (i6A) were employed to investigate the efficacy of various immunoadsorbents with respect to immobilization of antibody protein and with respect to their ability to bind i6A-containing tRNAs. Biologically active anti-i6A was recovered in high yield (80-88%) by affinity chromatography on i6A-adipate-Sepharose 4B or i6A-butane diglycidyl ether-Sepharose 4B using either 15% pyridine in phosphate-buffered saline or 0.2 M acetic acid as eluents. The binding capacity of various anti-i6A antibody immunoadsorbents was evaluated. While both anti-i6A antibody-protein A-agarose-iminothiolane (ITL) and anti-i6A antibody-protein A-agarose-dimethyl suberimidate showed a high capacity for i6A-tRNA, the latter column is much less efficient with respect to antibody immobilization. Under optimal conditions, the ITL immunoadsorbent binds 5-6 nmol of i6A/mg of antibody protein. With respect to bulk tRNA, 1 mg of antibody protein (ITL immunoadsorbent) binds all of the i6A-tRNA in a 1-mg sample.

The transfer RNA of certain Enterobacteriacae contain 2-methylthiozeatin riboside (ms2io6A) an isopentenyl adenosine derivative.

Isopentenyl adenosine derivatives are always located adjacent to the 3' end of the anticodon in transfer RNA and have been implicated in certain biological functions. In the enteric bacterium, E. coli, the derivative is ms2i6A whereas in some plant associated bacteria the derivative is the hydroxylated form, ms2io6A. Anti-i6A immunoadsorbent chromatography has been employed to detect isopentenyl adenosine compounds. In the present study we show that the transfer RNA of three species of enteric bacteria, S. typhimurium, K. pneumoniae, and S. marcescens contains both ms2io6A and ms2i6A. Under the growth conditions utilized the ms2io6A is predominant. The presence of ms2io6A in Enterobacteriacae is particularly noteworthy since in previous work it has been found only in plant-associated species of bacteria.

A modified quantitative precipitin test which is rapid, sensitive and reproducible.

A modification of the standard quantitative precipitin test is described. The new procedure, which utilizes polyethylene glycol (PEG) at both the 37 degrees C and 4 degrees C incubation stages, provides a convenient quantitative precipitin test assay which is more reliable and much faster than the standard assay. Moreover, the modified or PEG assay gives a quantitative measure of antibody concentration even when antisera of low titre are tested. The sensitivity of the capillary-tube test is also enhanced when the supernatant solutions contain PEG.