Nonsense mutations in the maltose A region of the genetic map of Escherichia coli

The isolation of one amber mutation in malQ, one ochre mutation in malP, and seven amber mutations in malT is reported. A study of their phenotypic expressions in the presence of the amber suppressor su(III) and the ochre suppressor su(c) suggests that (i) malQ is the structural gene for amylomaltase; (ii) malQ and the structural gene for maltodextrin phosphorylase, malP, belong to the same operon; (iii) the malT product, which promotes the expression of the malP-malQ operon, is a protein synthesized in limiting amounts by the wild-type strain.

Genetic analysis of the maltose A region in Escherichia coli

The genetic map of the maltose A locus of Escherichia coli contains at least three closely linked genes, malT, malP, and malQ. The order of these genes is established by deletion mapping. MalP and malQ, the presumed structural genes for maltodextrin phosphorylase and amylomaltase, belong to the same operon. MalT may be a regulator gene involved in the positive control of this operon.

Abnormally increased glomerular filtration rate in short-term insulin-treated diabetic subjects

Functional changes in the microvascular system appear to precede the morphological changes in the conjunctiva and retina of young subjects with diabetes mellitus. Similar functional changes might occur in the renal microvascular system and hemodynamics and possibly lead to a disturbance in the glomerular filtration rate.

A preliminary study of the glomerular filtration rate (GFR) using the radioactive vitamin B12 method in young, insulin-treated patients with short duration of diabetes is reported.

The average GFR in eighteen diabetic subjects was 137.8 ml. per min. per 1.73m2 with a standard deviation of 24.3 ml. in contrast to the average GFR in twelve control subjects which was 102.9 ml. with a standard deviation of 15.1 ml. This difference in GFR is highly significant. The reasons for the increased GFR in diabetics with short duration of their disease are discussed.

Location of the maltose A and B loci on the genetic map of Escherichia coli

Schwartz, Maxime (Institut Pasteur, Paris, France). Location of the maltose A and B loci on the genetic map of Escherichia coli. J. Bacteriol. 92:1083-1089. 1966.-All of the mutations impairing maltose metabolism that have been found in Escherichia coli map in one of the two loci, malA and malB. The position of malA in relation to the streptomycin, diaminopimelic acid + homoserine, and glycerol D loci were established both by sexual crosses and by P1 transduction. A new biotin marker was also shown to be located in this region. The position of malB was studied in relation to the loci for arginine F, methionine A, ultraviolet radiation A, and the origin of transfer of Hfr P10.

Somatosensory cerebral evoked responses in psychotic depression

In previous studies of somatosensory cerebral evoked responses in psychiatric patients, we found that two characteristics of these responses discriminated between patients with psychotic depressions and healthy or psychoneurotic subjects. The amplitude of the initial negative-positive component was larger and its recovery, as determined by administering paired “conditioning” and “test” stimuli, was retarded (11, 12, 13). Furthermore, after successful therapy, the recovery measure changed in the direction of “normal” (11).