Brain Regional Distribution of Glutamic Acid Decarboxylase, Choline Acetyltransferase, and Acetylcholinesterase in the Rat: Effects of Chronic Manganese Chloride Administration after Two Years

Abstract: Rats were treated chronically with manganese chloride from conception onward for a period of over 2 years in order to study the effects of manganese and aging on the activities of glutamic acid decarboxylase (GAD), choline acetyltransferase (ChAT), and acetylcholinesterase (AChE) in hypothalamus, cerebellum, pons and medulla, striatum, midbrain, and cerebral cortex (which included the hippocampus). Manganese-treated 2-month-old and 24- to 28-month-old rats and age-matched controls were studied. In control rats during aging the activities of GAD decreased in hypothalamus (19%), pons and medulla (28%), and midbrain (22%) whereas the activities of AChE decreased in all regions (20–48%), particularly in the striatum (44–48%). Changes in ChAT activities in aging were observed only in one region—a decrease (23%) in the striatum. Life-long treatment with manganese appeared to abolish partially the decreases in aging in AChE activities in hypothalamus, cerebellum and striatum, and striatal ChAT activity. Manganese treatment also seemed to abolish the age-related decreases in GAD activities, since GAD activities in various brain regions of manganese-treated senescent rats were not significantly different from those of control young rats. These results are discussed in relation to other metabolic changes associated with aging and manganese toxicity.     

Characterization of polypeptides immunoprecipitable from Pichinde virus-infected BHK-21 cells

Using hamster anti-Pichinde virus serum, we immunoprecipitated polypeptides from BHK-21 cells infected with Pichinde virus. Seven immunoprecipitable polypeptides exhibited a time- and multiplicity of infection-dependent appearance when the cultures were pulse-labeled with L-[35S]methionine for 1 h. The predominant polypeptide was a nucleoprotein (NP) of 64,000 daltons. Components of 48,000, 38,000, and 28,000 daltons, when analyzed by two-dimensional tryptic peptide mapping, were found to be derived from NP. After a 3-h chase period, polypeptides of 17,000, 16,500, and 14,000 daltons were evident, and peptide mapping revealed that these three polypeptides were also related to NP. During a series of pulse-chase experiments, a 79,000-dalton glycoprotein (GPC) was cleaved to glycoproteins of 52,000 and 36,000 daltons. Radiolabel in a polypeptide of approximately 200,000 daltons (L) did not chase into smaller cleavage products. L, GPC, and NP were found to be unique by two-dimensional tryptic peptide mapping. Comparison of polypeptides immunoprecipitated from infected cells with structural components of purified virus revealed that L protein was evident in both. This is the first report of a high-molecular-weight polypeptide in Pichinde virus particles and infected cells.     

Red-light- and gibberellic-acid-enhanced α-galactosidase activity in germinating lettuce seeds,cv. Grand Rapids

Dry lettuce (Lactuca sativa L.) seeds (achenes) contain -galactosidase (EC 3.2.122) at a level which is maintained in the imbibed dormant state in darkness. Both red light (R) and gibberellic acid promote an increase in enzyme activity several hours prior to the completion of germination. Germination and enzyme activity are not essentially linked, however, for the latter can increase while the former is inhibited. -Galactosidase activity increases within the cotyledons and the endosperm following R stimulation, but the axis is essential to perceive the stimulus and to promote and maintain the increase in enzyme activity. A diffusible factor (or factors) is produced by and-or released from irradiated axes, and it migrates to the cotyledons (and possibly endosperm) to promote the increase in -galactosidase activity. Gibberellic acid, particularly in the presence of benzyladenine, can replace the requirement for irradiated axes.Abbreviations GA₃ gibberellic acid - R red light     

Mobilisation of the major stored reserves in the embryo of fenugreek (Trigonella foenum-graecum L., Leguminosae), and correlated enzyme activities

Changes in total nitrogen, soluble amino nitrogen, lipid and phytate contents, and in the activities of proteinase (pH 7.0), isocitrate lyase and phytase were followed in the endosperm, cotyledons, and axis during germination of fenugreek seeds and subsequent growth of the seedlings. The endosperm is comprised largely of cell-wall galactomannans: the majority of the seed total nitrogen, lipid and phytate (5%, 8%, 0.44% of seed dry weight respectively) is localised within the cotyledons as stored reserves. Germination is completed after 10–14 h from the start of imbibition, but the major reserves are not mobilised during the first 24 h. Then the total nitrogen content of the cotyledons starts to decrease and that of the axis increases; there is a concomitant accumulation of soluble amino nitrogen in both cotyledons and axis. An increase in proteinase activity in the cotyledons correlates well with the depletion of total nitrogen therein. Depletion of lipid and phytate reserves in the different seed tissues constitutes a late event, occurring after 50 h from the start of imbibition, and is coincident with the final disintegration of the endosperm tissue. The depletion of phytate and stored lipids is accompanied by an increase in phytase and isocitrate lyase activity. It appears that the products of lipid hydrolysis are converted by gluconeogenesis to serve as the major source of sugars for the growing axis after the endosperm galactomannan has been completely mobilised.