摘要:

Three rapid and simple methods for the screening of free amino acids in urine and plasma are outlined. The first method employs electrophoresis on cellulose acetate; the second, thin layer chromatography on cellulose, and the third employs electrophoresis and chromatography on thin layer cellulose plates.

ISSN:0035-919X    

DOI:10.1080/00359197209519402

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

The isolation and characterization of two novel plant amino acids N-methyl alanine and N-methyl serine are described briefly. It is shown that these amino acids are not toxic and do not form part of Gifblaar protein. The concentration of these amino acids and fluoroacetate was determined in different parts of Gifblaar. In an examination of the amino acid composition of 16 other members of the Dichapetalaceae it was found that N-methyl alanine occurs in six and N-methyl serine in three other species ofDichapetalum.

ISSN:0035-919X    

DOI:10.1080/00359197209519403

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

ISSN:0035-919X    

DOI:10.1080/00359197209519404

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Slight transport of14C-valine fed to leaves ofDatura stramoniumL. was found to occur, mainly to fruits but also to roots. The intensity of translocation was affected by the age of the fed leaf, the age of the fruit, the duration of the experiment and the illumination of the plant. Mature leaves of plants kept in darkness do not export14C-valine in measurable amounts. The inhibition of export in darkness probably occurs in the leaf blade. The fed14C-valine is metabolized mainly to sucrose, glutamic acid and leucine. Among the amino acids of the proteins, valine carries the highest label, followed by leucine.

ISSN:0035-919X    

DOI:10.1080/00359197209519405

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

The mechanisms of experimental amino acid deficiency and imbalance are discussed with special reference to tryptophan. The anorexia in such dietary abnormalities prevents abnormal plasma levels of amino acids which have a regulatory function in protein synthesis, but contributes in the long run to protein deficiency. It is argued that in these conditions appetite is affected through amino acid effects on glucose utilization and that a maize diet produces a human counterpart.

ISSN:0035-919X    

DOI:10.1080/00359197209519406

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

The poor nutritional quality of maize protein is attributable to the zein fraction, which is very low in lysine and tryptophan, the first limiting amino acids in maize. The protein content of ‘normal’ maize can be increased by correct soil fertilization practices and by breeding but not without a reduction in biological value due to a disproportionate increase in zein relative to non-zein fractions. The discovery that the o2- and fl2- mutant genes alter the protein distribution pattern with a marked reduction in the proportion of zein, has made possible the production of high-lysine, high-tryptophan lines with a marked improvement in the quality of the maize proteins. Exploitation of this finding could lead to an improvement in the nutrition of the low-income population groups in this country.

ISSN:0035-919X    

DOI:10.1080/00359197209519407

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

The most marked and nutritionally valuable effect of the opaque-2 and floury-2 mutants is that the concentrations of the essential amino acids lysine and tryptophan are considerably increased in the endosperm proteins of the maize. In addition, an increased methionine content is associated with the floury-2 mutant. While this finding is of great potential benefit in the nutrition of human beings and monogastric animals, the action of these mutant genes is also associated with less desirable agronomic characteristics such as lower yields, a poorer grain quality and, in the case of the opaque-2 mutant, a lower protein percentage. The data presented highlight some of the breeding problems encountered in the recovery of existing élite breeding material in a programme of conversion to the mutant genes (the emphasis being on the opaque-2 gene). Final analysis suggests that sufficient genetic variation exists in respect of most of the important agronomic and nutritional factors associated with high-lysine maize to attain its full potential by selection and breeding.

ISSN:0035-919X    

DOI:10.1080/00359197209519408

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

ISSN:0035-919X    

DOI:10.1080/00359197209519409

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Evidence is presented for the role of certain naturally occurring amino acids as centrally acting excitatory and inhibitory neuro-transmitters. The suggestion is made that the relative balance between them at various central synaptic sites could be important for the normal functioning of the central nervous system. Any excessive shifting of this synaptic balance might give rise to, or support the development of, various neuro-psychiatric syndromes. Therapeutic approaches based on these concepts are briefly touched on.

ISSN:0035-919X    

DOI:10.1080/00359197209519410

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

ISSN:0035-919X    

DOI:10.1080/00359197209519411

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor