Cortical mechanisms and cues for action

Monkeys have more highly developed brains and are more intelligent than rats; yet rats learn some tasks as efficiently as monkeys. For example, rats are as quick at discovering which of two doors hides food or how to open the doors. Presumably tasks of this sort do not greatly tax cortical associative mechanisms since the animals have only to cumulate facts about objects. It is argued that cortical mechanisms are crucial for the ability to relate together information that is presented at different times or in different places. After removal of parts of frontal cortex monkeys can still associate cues that are presented together but they are poor at relating cues that are presented apart.     

Post-translational heterogeneity of the human vitamin D-binding protein (group-specific component)

The vitamin D-binding protein in human serum (the group-specific component) is an alpha 2-globulin which is genetically polymorphic in all populations studied. Previous work (J. Svasti and B. H. Bowman (1978) J. Biol. Chem. 253, 5188-5194, and J. Svasti, A. Kurosky, A. Bennett, and B. H. Bowman (1979) Biochemistry 18, 1611-1617) has shown that the electrophoretic variations of the proteins controlled by two allelic genes, Gc1 and Gc2, are due to at least three amino acid substitutions between Gc1 and Gc2 (Svasti et al. (1979] and to heterogeneity in the Gc1 phenotype arising from carbohydrate dissimilarities. Gc1 migrates electrophoretically as two protein bands, while Gc2 migrates cathodally as a single band. This study demonstrates a post-translational glycosylation difference occurring in a single area of the Gc1 sequence which accounts for the heterogeneity observed previously. The glycosylation site, a threonine residue, appears to be in a sequence which differs between Gc1 and Gc2. The O-glycosidic bond, which is typical of mucins, is rare in plasma proteins. The cyanogen bromide fragment containing the galactosamine-containing carbohydrate in Gc1 was partially sequenced through 20 residues from the amino terminus. No detectable galactosamine could be found in the homologous cyanogen bromide fragment in Gc2. A new purification procedure for the vitamin D-binding protein in human plasma has been developed. Three chromatographic steps provide purified protein.     

Kinetics of histone H10 accumulation and commitment to differentiation in murine erythroleukemia cells

The accumulation of histone H10 (also denoted IP 25) in murine erythroleukemia cells, induced to differentiate with hexamethylene bis-acetamide, was shown to precede by 15-20 h the appearance in the culture of cells irreversibly committed to differentiate. In addition the rates of accumulation of H10 and of committed cells vary in a similar manner with the HMBA concentration. Flow microfluorimetric analysis demonstrated that the accumulation of H10 did not occur simultaneously in all the cells. This accumulation of histone H10 was initiated first in cell in the G2 phase of the cell cycle and subsequently in the cells situated in all the phases of the cell cycle.     

Population Changes of Heterodera glycines and Soybean Yields Resulting from Soil Treatment with Alachlor,Fenamiphos, and Ethoprop

The population dynamics of Heterodera glycines as influenced by alachlor, fenamiphos, and ethoprop alone and in herbicide-nematicide combinations were studied in the field. Numbers of H. glycines juveniles and eggs were higher at midseason and harvest where nematicides were applied. Fenamiphos alone or in combination with alachlor provided better control of H. glycines and greater seed yields than treatments with ethoprop. Numbers of H. glycines eggs at harvest in 1980 were positively correlated with numbers of juveniles at planting in 1981 and negatively related to seed yield in 1981.     

Role of sodium on H+ excretion in the integument of the leopard frog Rana pipiens

1. The northern leopard frog, Rana pipiens, pipiens, in contrast to the southern leopard frog, Rana pipiens, berlandieri, did not demonstrate any significant H+ excretion across its integument even during a challenge of chronic metabolic acidosis. Likewise, no increase in the number of H+ secreting mitochondria-rich cells were observed in the northern frogs. 2. Under normal acid-base conditions in the southern frogs, H+ excretion was found to be dependent on mucosal sodium concentrations, whereas during chronic metabolic acidosis, H+ excretion was independent of mucosal sodium concentrations, but was amiloride sensitive. 3. High salinity adapted southern frogs, under normal and acidotic conditions, had enhanced H+ excretion rates as compared to the control non-salt adapted frogs. 4. Blood analyses demonstrated that significant acid-base changes were the result of systemic acidosis and not due to salt adaptations. Blood Na+ and K+ concentrations were also efficiently maintained during salt adaptations or chronic metabolic acidosis. 5. The results suggest that H+ excretion in epithelia can be influenced by the sodium transport state of the cell and the systemic acid-base profile. Models are proposed explaining these relationships.     

Profile of the alpha-bungarotoxin-binding regions on the extracellular part of the alpha-chain of Torpedo californica acetylcholine receptor.

The continuous alpha-neurotoxin-binding regions on the extracellular part (residues 1-210) of the alpha-chain of Torpedo californica acetylcholine receptor were localized by reaction of 125I-labelled alpha-bungarotoxin with synthetic overlapping peptides spanning this entire part of the chain. The specificity of the binding was confirmed by inhibition with unlabelled toxin and, for appropriate peptides, with unlabelled anti-(acetylcholine receptor) antibodies. Five toxin-binding regions were localized within residues 1-10, 32-41, 100-115, 122-150 and 182-198. The third, fourth and fifth (and to a lesser extent the first and second) toxin-binding regions overlapped with regions recognized by anti-(acetylcholine receptor) antibodies. The five toxin-binding regions may be distinct sites or, alternatively, different 'faces' in one (or more) sites.     

Some dermatoglyphic traits in breast carcinoma

The finger and palmar prints of 60 women with breast carcinoma were studied. The results were compared with two groups of healthy women, the first consisted of old women and the second of young women. The dermatoglyphics seem to be of little use in the diagnosis of cancers of ectodermic origin. Supported by M.P.I. 60%, 1983