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Biomedical subjects

R L Frank

Publications and source records attributed to R L Frank.

7 recordsLinked to original sources

Sequence and structure of a phenylalanine ammonia-lyase gene from Glycine max.

The gene encoding a key enzyme in anthocyanin biosynthesis, phenylalanine ammonia-lyase (PAL), was cloned from soybean (Glycine max). The purpose was to obtain a molecular probe to study the organization of this gene family in soybean and to examine novel regulatory mechanisms present in the anthocyanin biosynthetic pathway of this system. A soybean genomic library was constructed in the bacteriophage vector lambda Charon 35. A PAL cDNA clone from Phaseolus vulgaris was used in screening the library, and two PAL genes were isolated. One gene was sequenced entirely and analyzed by sequence homology to the PAL2 gene of Phaseolus vulgaris. Genomic analysis indicates that PAL sequences of Glycine max exist as a small gene family consisting of only two to three members. The representative PAL gene sequenced (PAL1) has a coding region of 2142 basepairs divided among two exons. The single intron is 1519 basepairs and splits the 131st codon.

Amino Acid Sequence

Characterization of two abundantly expressed constitutive genes of Neurospora crassa.

Two abundantly expressed, constitutive genes of Neurospora crassa were isolated during differential screening of Neurospora genomic libraries. The coding regions of these two genes, designated RLF1 and RLF3, were identified by hybridization of the cloned DNA sequences with cDNA probes made from polyadenylated RNA. The RLF3 gene was carried on a 15-kilobase Neurospora BamHI DNA fragment present in a lambda 1059 recombinant; a 2-kilobase restriction fragment that contains RLF3 was subcloned into plasmid pBR322 prior to further characterization. Southern blot analysis revealed that both RLF1 and RLF3 are single copy genes. Northern blot analysis and S1 nuclease mapping demonstrated that RLF1 is transcribed to yield a 1.6-kilobase RNA, whereas RLF3 appears to give rise to two distinct sized RNA species of 1.0 and 1.6 kilobases. RNA dot blot analysis provided conclusive evidence that both of these genes are constitutively expressed. These constitutive genes will be valuable to provide a detailed comparison with the 5' flanking regions of regulated genes.

Cloning, Molecular

Sodium and potassium intakes and excretions of normal men consuming sodium chloride or a 1:1 mixture of sodium and potassium chlorides.

Two groups of 10 healthy young men were matched on the basis of their free-choice consumptions of regular table salt. For 28 days they were then fed carefully controlled low-sodium foods. One group was permitted free-choice seasoning of these foods with regular table salt, the other with a 1:1 mixture of sodium and potassium chlorides. Intakes and urinary and fecal excretions of sodium and potassium were determined by analysis. The results were: 1) the subjects salted their food with essentially the same amounts of regular table salt as of the 1:1 mixture; 2) the sodium intake associated with seasoning at the table was reduced with the 1:1 mixture to 44 percent of the amount consumed with regular table salt; and 3) over a 28-day period there was no tendency for subjects to increase their use of a 1:1 mixture, when used in place of regular table salt, to compensate for their reduced sodium intakes. Under the conditions of this study, the use of the 1:1 mixture as a seasoning agent for foods that contained no added salt resulted in an average total intake of sodium (food plus seasoning) which was 55 percent that of the subjects using regular table salt.

Adult