https://mmbr.asm.org/content/mmbr/48/1/60.full.pdf

Mutagenesis and inducible responses to deoxyribonucleic acid damage in Escherichia coli.

2. Evidence for A m i n o Acids as T ransmi t t e r s . . . . . . . . . . . . . . . . . . . . 99 2.1. Synthesis and Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 2.2. Synapt ic Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 2.3. Postsynapt ic Act ion . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 2.4. Postsynapt ic An tagon i s t s . . . . . . . . . . . . . . . . . . . . . . . . . 103 2.5. Inac t iva t ion and R e m o v a l . . . . . . . . . . . . . . . . . . . . . . . . . 104

Amino acid transmitters in the mammalian central nervous system

The crystal structure of the nucleosome core particle has been solved to 7 A resolution. The right-handed B-DNA superhelix on the outside contains several sharp bends and makes numerous interactions with the histone octamer within. The central turn of superhelix and H3 . H4 tetramer have dyad symmetry, but the H2A . H2B dimers show departures due to interparticle associations.

Structure of the nucleosome core particle at 7 Å resolution

Amino acids and related compounds were measured in various regions of brain obtained at autopsy from eight neurologically normal persons, one patient with Parkinson's disease, and eight patients with Huntington's chorea. γ-Aminobutyric acid (GABA) and homocarnosine, a related dipeptide, were reduced in the substantia nlgra, putamen-globus-pallidus, and caudate nucleus of the choreic patients, as compared to the normal subjects and the patient with Parkinsonism. Glycerophosphoethanolamine concentration was elevated in these three regions of choreic brain. Deficiency of γ-aminobutyric acid, a possible inhibitory synaptic transmitter in brain, might produce the symptoms characteristic of Huntington's chorea. Such a deficiency could result from reduced activity of the enzyme glutamic acid decarboxylase, or might reflect a decrease in the number of neurons that normally utilize γ-aminobutyric acid as a transmitter.

Huntington's chorea. Deficiency of gamma-aminobutyric acid in brain.

Several techniques have recently been developed to detect single-base mismatches in DNA heteroduplexes that contain one strand of wild-type and one strand of mutated DNA. Here we tested the hypothesis that an appropriate system of mildly denaturing solvents can amplify the tendency of single-base mismatches to produce conformational changes, such as bends in the double helix, and thereby increase the differential migration of DNA heteroduplexes and homoduplexes during gel electrophoresis. The best separations of heteroduplexes and homoduplexes were obtained with a standard 6% polyacrylamide gel polymerized in 10% ethylene glycol/15% formamide/Tris-taurine buffer. As predicted by the hypothesis of solvent-induced bends, when the concentration of either ethylene glycol or formamide was increased, the differential migration decreased. Also, single-base mismatches within 50 bp of one end of a heteroduplex did not produce differential migration. Sixty of 68 single-base mismatches in a series of PCR products were detected in some 59 different sequence contexts. The eight mismatches not detected were either within 50 bp of the nearest end of the PCR product or in isolated high-melting-temperature domains. Therefore, it was possible to predict in advance the end regions and sequence contexts in which mismatches may be difficult to detect. The procedure can be applied to any PCR products of 200-800 bp and requires no special equipment or preparation of samples.

https://www.pnas.org/content/pnas/90/21/10325.full.pdf

Conformation-sensitive gel electrophoresis for rapid detection of single-base differences in double-stranded PCR products and DNA fragments: evidence for solvent-induced bends in DNA heteroduplexes

Initiation of deoxyribonucleic acid replication at the nuclear membrane in human cells.

Conformation changes of the double-stranded DNA helix in response to dehydration were investigated by monitoring, by agarose gel electrophoresis, the linking number of covalently closed circular DNA generated by ligation of linear DNA in the presence of different organic solvents or different temperatures. It was found that: (i) The DNA helix unwinds upon addition of certain organic solvents or elevation of temperature. (ii) The conformational change observed under the experimental conditions is a continuous process in response to the organic solvent concentration. (iii) The delta H of unwinding one linking of the DNA helix is constant at approximately 12.2 +/- 0.4 kcal/mol (1 kcal = 4.184 kJ); the corresponding delta S and d(delta S)/dn are 2nkR and 2kR, in which n is the relative equivalent linking number (referred to the state of delta S = 0 for unwinding) of the DNA, R is the gas constant, and k is equal to 1117/number of base pairs. The delta H, delta S, and d(delta S)/dn for unwinding i linkings are i X 12.2 kcal/mol, 2inkR, and 2ikR, respectively. (iv) d(delta S)/dn, like k, is inversely proportional to the number of base pairs in DNA. (v) Double-stranded DNAs of different chain lengths have average delta S = 35 cal/mol.K for unwinding one linking under the experimental conditions; this corresponds to 127 +/- 14 base pairs per "relative linking."

https://www.pnas.org/content/pnas/78/5/2838.full.pdf

Unwinding of double-stranded DNA helix by dehydration.

Since HeLa cells are one of the most commonly studied established cell lines, there is a need for a simple and rapid method for isolating enzymatically active cell nuclei which are not aggregated and thus can be pipetted in reproducible aliquots . We report here such a procedure which may be used for both large and small volumes of suspension cultures and which requires no specialized equipment. The method is a modification of previous techniques (1-3), all of which are based upon the use of Triton detergents . Although several other procedures for isolating HeLa cell nuclei have been published (4-7), the convenience and utility of the present method warrant consideration .

https://rupress.org/jcb/article-pdf/42/3/851/1069254/851.pdf

Tsuyoshi Kakefuda

Papers

Initiation of deoxyribonucleic acid replication at the nuclear membrane in human cells.

Unwinding of double-stranded DNA helix by dehydration.

A simple and rapid method for the isolation of enzymatically active HeLa cell nuclei.

Association of the γ-aminobutyric acid system with a synaptic vesicle fraction from mouse brain

Sodium-dependent binding of γ-aminobutyric acid by morphologically characterized subcellular brain particles☆