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Biomedical subjects

M Bevan

Publications and source records attributed to M Bevan.

47 records · Page 3Linked to original sources
PubMed1986

The structure and transcription start site of a major potato tuber protein gene.

We have isolated recombinant lambda clones containing intact major tuber protein (patatin) genes and flanking sequences from the commercial tetraploid variety Maris Piper. The gene is composed of seven exons and six introns, spread over 4 kb of DNA. Nuclease mapping defined the 5' end of the mRNA approximately 45 bp upstream of the initiation codon. The 5' end of the gene is preceeded by a canonical TATA box sequence. The three known patatin genes encode proteins of nearly identical Mr but very different isoelectric points. The sequence of the gene does not indicate a role for patatin as one of the globulin class of plant storage proteins.

Amino Acid Sequence↗
PubMed1984

Binary Agrobacterium vectors for plant transformation.

A vector molecule for the efficient transformation of higher plants has been constructed with several features that make it efficient to use. It utilizes the trans acting functions of the vir region of a co-resident Ti plasmid in Agrobacterium tumefaciens to transfer sequences bordered by left and right T-DNA border sequences into the nuclear genome of plants. The T-region contains a dominant selectable marker gene that confers high levels of resistance to kanamycin, and a lac alpha-complementing region from M13mp19 that contains several unique restriction sites for the positive selection of inserted DNA.

Amino Acid Oxidoreductases↗
PubMed1983

Kilo-sequencing: an ordered strategy for rapid DNA sequence data acquisition.

A strategy for rapid DNA sequence acquisition in an ordered, nonrandom manner, while retaining all of the conveniences of the dideoxy method with M13 transducing phage DNA template, is described. Target DNA 3 to 14 kb in size can be stably carried by our M13 vectors. Suitable targets are stretches of DNA which lack an enzyme recognition site which is unique on our cloning vectors and adjacent to the sequencing primer; current sites that are so useful when lacking are Pst, Xba, HindIII, BglII, EcoRI. By an in vitro procedure, we cut RF DNA once randomly and once specifically, to create thousands of deletions which start at the unique restriction site adjacent to the dideoxy sequencing primer and extend various distances across the target DNA. Phage carrying a desired size of deletions, whose DNA as template will give rise to DNA sequence data in a desired location along the target DNA, may be purified by electrophoresis alive on agarose gels. Phage running in the same location on the agarose gel thus conveniently give rise to nucleotide sequence data from the same kilobase of target DNA.

Base Sequence↗
PubMed1983

Structure and transcription of the nopaline synthase gene region of T-DNA.

We present the DNA sequence and plant-tumor transcription pattern of some 2400 base pairs from the right border region of pTi T37 DNA from the virulent Agrobacterium tumefaciens strain T37. This region includes the entire transcription unit encompassing the nopaline synthase gene, together with parts of other transcription units. The strategy used to determine the sequence also produced two opposing series of defined, asymmetric deletions across the target DNA region, some of which may serve future purposes in the exploitation of this sequence, which is known to be expressed in a wide variety of host plant tissues.

Amino Acid Oxidoreductases↗
PubMed1982

The effects of oral propranolol and indomethacin on the response to inhaled PGE2 in normal human subjects.

The effects of oral propranolol and oral indomethacin on the normal response to inhaled PGE2 has been studied in 8 human volunteers. Inhalation dose-response curves to PGE2 in doses from 10 to 400 micrograms were constructed on three separate occasions. Either 80 mg or propranolol, 50 mg of indomethacin or identical placebo tablets were ingested 1 1/2 hours before PGE2 inhalation in random order and double blind. Propranolol had no effect of PGE2 induced bronchodilatation. In most subjects indomethacin caused a small baseline bronchodilatation and enhancement of PGE2 effect. In 2 subjects, however, indomethacin caused almost complete suppression of PGE2 bronchodilatation.

Administration, Oral↗
PubMed1982

Interactions between response to inhaled prostaglandin E2 and chronic beta-adrenergic agonist treatment.

Cumulative inhalation dose-response curves for the response to prostaglandin E2 (PGE2) have been constructed in normal subjects and patients with mild, stable asthma. In normal subjects cumulative inhalation dose-response curves were also constructed for salbutamol. In normal subjects dose-related bronchodilatation occurred in response to both PGE2 and salbutamol, although both the within-subject and the between-subject variation was significantly greater with salbutamol. Most asthmatic subjects gave a biphasic response to PGE2 on at least one occasion, PGE2 being a bronchoconstrictor above a certain level of specific airways conductance (sGaw) and a bronchodilator below. Chronic treatment with inhaled salbutamol (400 micrograms four times a day) had no effect on the normal subjects' response to salbutamol but there was a significant shift of the PGE2 dose-response curve to the left, indicating increased bronchodilatation (p less than 0.02). Stabilisation of the asthmatics' dose-response curve in the direction of bronchodilatation also occurred and was more pronounced (p less than 0.005). In the normal subjects PGE2 may be concerned in the control of airway smooth-muscle tone and in limiting bronchoconstriction induced by mediators such as histamine, and chronic salbutamol treatment may be important in enhancing these effects of PGE2. 80 mg oral propranolol given one and a half hours before had no effect on PGE2-induced bronchodilatation; but the question whether chronic treatment with beta-blockers has any effect needs investigation.

Adult↗
PubMed1979

The loss of morphogenetic potential and induction of phenylalanine ammonia-lyase in suspension cultures of Phaseolus vulgaris.

The loss of morphogenetic potential in bean suspension cultures has been investigated by measuring the amounts of phenylalanine ammonia-lyase activity induced in the cells when they are transferred from a medium in which they are grown and maintained to an induction medium. The tissue has been grown in 2 types of medium: (1) supplemented with 2,4-dichlorophenoxyacetic acid as the only growth hormone, and (2) supplemented with 2,4-dichlorophenoxyacetic acid and coconut milk. When cells were grown in medium with only 2,4-dichlorophenoxyacetic acid for a period of 5--10 subcultures and samples were transferred to the induction medium at intervals during the subcultures, the amounts of phenylalanine ammonia-lyase activity and the number of xylem elements induced progressively declined. Cells grown in the presence of coconut milk did not lose the ability to induce phenylalanine ammonia-lyase or xylem elements. Cells grown in the presence of coconut milk were cloned and clones capable of producing different amounts of phenylalanine ammonia-lyase when transferred to induction medium were obtained. However, clones producing low amounts of activity did not grow faster in the medium lacking coconut milk and no evidence was obtained to show that selective growth of non-inducible cells was responsible for the loss of morphogenetic potential. In addition to the induction brought about by the presence of naphthylacetic acid and kinetin in the induction medium the cells could also be stimulated to produce phenylalanine ammonia-lyase activity by dilution at subculture. This increase in activity occurred within 10 h of the dilution, whereas that produced by the hormones in the induction medium occurred after 120 h. The induction produced by dilution also occurred in these cells which had lost their ability to respond to the hormonal induction. Thus the mechanism that produced the increase in phenylalanine ammonia-lyase activity was intact but had lost its ability to respond to the hormones of the induction medium. The loss of inducibility was therefore probably not due to a genetic change in the cells brought about by continuous growth in a medium lacking coconut milk, but to reversible changes in the hormonal requirements of the cells necessary for induction.

2,4-Dichlorophenoxyacetic Acid↗
PubMedDate not supplied

The older person with renal failure.

The number of older people with end-stage renal failure is increasing. Mark Bevan describes the implications this will have for renal nurses, and others working with elderly people in renal failure.

Age Distribution↗