Showing papers on "Low protein published in 1971"
TL;DR: In-vitro studies of breast and cow's milk preparations, and of the faeces from breast-fed and bottle-fed infants, a number of factors seemed likely to influence the production and maintenance of a lactobacillary flora and low pH in the faes of newborn infants, mainly attributable to the nature of the feed.
Abstract: From in-vitro studies of breast and cow9s milk preparations, and of the faeces from breast-fed and bottle-fed infants, a number of factors seemed likely to influence the production and maintenance of a lactobacillary flora and low pH in the faeces of newborn infants. These were mainly attributable to the nature of the feed. It is suggested that responsible factors in breast milk include its high lactose, low protein, low phosphate content, together with its poor buffering capacity. Importance is also attached to the fact that breast milk seems to provide a fluid feed of small bulk and low residue, and that its use is unlikely to include periods of starvation. Cow9s milk, on the other hand, which has a low lactose, high protein, high phosphate content, and a high buffering capacity, is a relatively bulky, high-residue feed. Feeding regimens which employ it are likely to include periods of starvation.
165 citations
Journal Article•
TL;DR: Autochthonous tumour cell membrane extracts produced delayed hypersensitivity reactions in patients with a variety of neoplastic diseases when tested at low protein concentrations (≤0·33 mg/0·1 ml).
Abstract: Autochthonous tumour cell membrane extracts produced delayed hypersensitivity reactions in patients with a variety of neoplastic diseases When tested at low protein concentrations (≤0·33 mg/0·1 ml), autochthonous tumour extracts produced positive reactions in 50% of non-anergic cancer patients The same dose of autochthonous leucocyte membranes produced a significantly lower incidence of positive reactions (10%) in normal volunteers In contrast, the cancer patients were less reactive than the normal volunteers to a battery of standard skin test antigens In patients with acute lymphocytic leukaemia, positive reactions were more often obtained during remission The protein concentration of the extracts was found to be an important factor in these studies Extracts with high protein concentrations elicited positive reactions in both the patients and in the normal volunteers It remains to be determined whether the reactions to the high protein concentrations are due to non-specific inflammation or to a low level of autoimmunity in both patients and controls
108 citations
TL;DR: LP rats were less adaptable than the control and UN rats in adjusting food intake during the period of restricted access, and spent most time in the arms, in contrast to the UN rats, which made most visits to the arms.
Abstract: Male hooded rats were divided into 3 equal groups: (1) controls were given a complete diet ad libitum at all times; (2) for 8 weeks from the age of 28 days, undernourished (UN) rats received the complete diet in restricted amounts; (3) low protein (LP) rats received a low-protein, high-carbohydrate diet for the same period. From 12 weeks all rats were given the complete diet ad libitum, until tested at 35 weeks. Each rat was then put alone, for 12 days, in a residential “plus-maze” with a central nest box and 4 arms radiating from it; food was supplied at the end of one arm, water in the nest box. On Days 4 to 9 each rat had access to the arms for only 1 hr daily. Entries into the arms, and duration of stay, were recorded automatically. All arms were regularly visited by rats of all classes, even when access was only for 1 hr. Visits per day to the 3 nonfood arms combined were usually higher than visits to the food arm, but duration of stay in the food arm was higher than the total duration in the other 3 arms. LP rats made most visits to the arms and were especially active after the 6 days of restriction; but they were less adaptable than the control and UN rats in adjusting food intake during the period of restricted access. In contrast, the UN rats spent most time in the arms.
79 citations
TL;DR: Malnutrition is a widespread problem in the tropical regions of the world, and selection against individuals unable to make suitable adjustments exerts pressure on the human population to retain adaptability while maintaining appropriate body proportions and sexual dimorphisms for body size.
Abstract: Malnutrition is a widespread problem in the tropical regions of the world, the same areas which are believed to be man's ancestral home. Much of the adaptive complex characterizing contemporary Homo sapiens was assembled during the period of at least partial reliance on dietary intake of animal protein. Adjustments to low protein intake are most difficult during the period of growth and development. Selection against individuals unable to make suitable adjustments exerts pressure on the human population to retain adaptability while maintaining appropriate body proportions and sexual dimorphisms for body size.
69 citations
TL;DR: It is concluded that Ascaris infection in children can lead to marked nutritional impairment when a high parasite load is associated with a low protein intake.
Abstract: The role of Ascaris lumbricoides infection in human nutrition was investigated in 12 children 5 to 10 years of age. Daily levels of dietary protein intake varied from 1 to 2.8 g per kg of body weight but were kept constant for each child, as was caloric intake. Nitrogen, fat balance, and d-xylose absorption determinations were done before and after deworming. A mean reduction in fecal nitrogen excretion of 230 mg per day was noted after removal of worms. In 7 children harboring 48 or more parasties, the reduction in fecal nitrogen amounted to 7.2% of the dietary nitrogen. In 3 children receiving 1 g of protein per kg body weight, the improved nitrogen absorpiton after deworming led to an increased nitrogen retention. In 8 children the infection was associated with moderate steatorrhea (13.4% of dietary fat) and impairment of d-xylose absorption; the former was markedly reduced, and the latter partially improved following treatment. It is concluded that Ascaris infection in children can lead to marked nutritional impairment when a high parasite load is associated with a low protein intake.
68 citations
TL;DR: In this paper, corn silages (34 to 37% dry matter) ensiled with no additive were fed as the only forage to lactating cows averaging 29.3kg milk per day when treatment began.
57 citations
TL;DR: The effect of ethanol on nitrogen balance persisted in animals fed low protein diets, incriminating altera tion of protein metabolism induced by ethanol rather than increased colonie breakdown of unabsorbed amino acids.
Abstract: To test the role of defective intestinal absorption produced by ethanol on the pathogenesis of alcohol-induced fatty liver, fat and nitrogen bal ances were studied in rats pair-fed nutritionally adequate liquid diets containing ethanol (36% of calories) or isocaloric carbohydrate (controls). Alcohol feeding resulted in three- to fourfold increase in hepatic triglycA©rideconcentration, whereas low protein feeding (4% of calories) only doubled it. Ethanol did not affect either fecal fat or nitrogen excretion or ileal losses of nitrogen, but in creased significantly the urinary excretion of nitrogen. This effect of ethanol on nitrogen balance persisted in animals fed low protein diets, incriminating altera tion of protein metabolism induced by ethanol rather than increased colonie breakdown of unabsorbed amino acids. J. Nutr. 101: 1307-1310, 1971.
55 citations
TL;DR: The “ effective “ percentage of protein required in the 6 to 10‐week stage, defined as the level which subsequently allowed maximum body weight at 20 weeks of age, was less for initially fully fed birds, who had smaller growth deficits at 10 weeks and consequently made faster recovery in the limited time allowed.
Abstract: Synopsis An adequate and a low protein starter diet (29 and 20 per cent crude protein respectively) were fed from o to 6 weeks of age. The poults receiving only 20 per cent protein were 17 per cent lighter at 6 weeks than the fully fed group. Turkeys from each treatment were then fed one of five levels of protein from 6 to 10 weeks of age. After 10 weeks all groups were fed adequate levels of protein to allow undernourished poults to exhibit compensatory growth. The percentage protein required for maximum growth in the 6 to 10‐week stage was similar whether turkeys had been fully fed or undernourished from 0 to 6 weeks. But the “ effective “ percentage of protein required in the 6 to 10‐week stage, defined as the level which subsequently allowed maximum body weight at 20 weeks of age, was less for initially fully fed birds. This was because they had smaller growth deficits at 10 weeks and consequently made faster recovery in the limited time allowed. Turkeys fed 29 and 17 per cent protein or 20 and 22 per...
52 citations
TL;DR: Poults fed the low protein starter diet retained nitrogen more efficiently during the period of undernutrition and in the first stages of recuperation.
Abstract: Synopsis Turkey poults were fed starter diets containing either 29 or 20 per cent crude protein. Live‐weight at 6 weeks was depressed by about 30 per cent in poults fed the low protein diet. From 6 to 10 weeks of age four protein levels were fed but carcass studies were restricted to the groups which received adequate amounts of protein at this stage. Sixty poults from each treatment were slaughtered for carcass studies at 6 weeks of age, and also at 7 weeks when the undernourished poults had reached the body weight attained by fully fed groups at 6 weeks. Further samples were taken for carcass analysis at 20 weeks of age. Percentage body fat was increased and percentage protein in the fat‐free dry matter was decreased by feeding a low protein starter diet from o to 6 weeks. Poults fed the low protein starter diet retained nitrogen more efficiently during the period of undernutrition and in the first stages of recuperation. Following a return to full feeding at six weeks, body protein content was quickly ...
47 citations
TL;DR: The intracellular IgMs cysteine residues responsible for inter-IgMs linkage therefore appear to be reversibly blocked within the cells, and Assembly into IgM is thus controlled by removal of this block during secretion.
Abstract: We have shown previously that immunoglobulin M (IgM) is present within IgM-forming cells mainly in its 7S subunit form (IgMs), whereas only fully assembled IgM pentamers are secreted. There is no spontaneous polymerization of intracellular IgMs in cell lysates, suggesting that the 7S subunits had blocked cysteine residues. This suggestion was explored and confirmed in the present paper. Radioactive IgM (secreted) and IgMs (intracellular) were prepared by sucrose-density-gradient centrifugation after incubation of cells of the IgM-producing mouse myeloma MOPC 104E with [3H]leucine. We investigated the susceptibility to reduction of fully assembled mouse IgM and its reconstitution from subunits by analysis by polyacrylamide-gel electrophoresis under dissociating conditions. With increasing concentrations of dithioerythritol, interchain disulphide bonds were cleaved in the following order: inter-IgMs subunit, intra-IgMs subunit H-H, intra-IgMs subunit H-L. Removal of the reducing agent from IgM-reduction mixtures by filtration through Sephadex G-25 caused partial reconstitution of IgM at low protein concentrations (5–100μg/ml) and total reconstitution at higher protein concentrations (300μg/ml or more). Isolated radioactive intracellular IgMs showed no tendency to polymerize unless first treated with a reducing agent; under optimum conditions removal of the reducing agent caused 70% of the subunits to be assembled into IgM. Similar assembly occurred when IgMs was isolated from cells that had been lysed in the presence of an irreversible alkylating reagent (iodoacetamide). The intracellular IgMs cysteine residues responsible for inter-IgMs linkage therefore appear to be reversibly blocked within the cells. Assembly into IgM is thus controlled by removal of this block during secretion.
45 citations
TL;DR: Comparison of height, weight and subscapula skinfold values show that the Manus children resemble the Kaiapit and Bundi children of the New Guinea highlands populations reported by Malcolm in the form of their growth curves but not in growth rates.
Abstract: The growth and somatotype patterns of Manus children, Territory of Papua and New Guinea, reflected in anthropometric measurements and somatotype photographs, is reported for 438 children, ranging from 15 months of age to maturity. Somatotype distributions and individual somatotype photographs indicate little difference between boys and girls from age 1 to 4 years; between age 5 and 9 years boys shift toward higher second component ratings; between age 10 and 18 years boys shift toward higher second and third component ratings, while girls shift toward higher first and third component ratings. Four sample somatotype photographs are representative of the population at age 10 and 14 years, and show age and sex characters easily noted visually. Comparison of height, weight and subscapula skinfold values show that the Manus children resemble the Kaiapit and Bundi children of the New Guinea highlands populations reported by Malcolm in the form of their growth curves but not in growth rates. Manus children grow more slowly than the British, but faster than the Kaiapit and Bundi children. While low skinfold values and height/weight ratios derived from means for height and weight suggest somatotypic similarity of the Manus, Kaiapit and Bundi populations, somatotype photographs are needed for confirmation. Lacking historical information and genetic evidence, we can speculare that diet, nutrition, climate and perhaps physical activity are factors which influence the growth patterns of these populations. The protein intake derived from fish and other seafood may be an important factor in the relatively fast growth and earlier maturation of the Manus. Malcolm thinks that low protein intake plays an important role with the Kaiapit and Bundi, but does not rule out survival value of slow growth and short stature.
TL;DR: It is found that diets marginal in lipotropes result in remarkable differences in the response of rats to aflatoxin, and these differences are of more practical significance than low protein per se in the overall evaluation of interactions between nutrition and a Flatoxin and their relation to carcinogenesis.
Abstract: ALTHOUGH malnutrition and aflatoxins coexist in many areas of the world where there is a high incidence of liver disease and hepatocarcinoma, animal experiments so far have not precisely duplicated the disease syndrome and the morphological picture observed in man1–8. We have examined interactions between nutritionally induced liver disease and experimental aflatoxin carcinogenesis and found that diets marginal in lipotropes result in remarkable differences in the response of rats to aflatoxin. This work was suggested by observations that diets low in protein had variable effects7,9 on aflatoxin toxicity and carcinogenicity. Furthermore, dietary lipotropes, expecially methionine and vitamin B12, may be critically low in many areas where liver carcinoma and mycotoxins coexist, and so we considered marginal lipotropes to be of more practical significance than low protein per se in the overall evaluation of interactions between nutrition and aflatoxin and their relation to carcinogenesis.
TL;DR: Analyses by both atomic absorption spectrometry and the dithizone method showed that zinc was always present in the ratio of 2 atoms per molecule, and it is proposed that pig kidney particulate aminopeptidase is a Zn-containing glycoportein.
Abstract: Pig kidney particulate aminopeptidase (EC 3.4.1.2) was purified by a modification of the procedure of Wachsmuth et al. [3] to a state of homogeneity according to criteria of ultracentrifugation and polyacrylamide gel electrophoresis, and some of its physical and chemical properties were determined.
The purified enzyme (specific activity 30 ± 3 μmoles leucine-p-nitroanilide hydrolyzed/min/mg) has a s20,w = 9.82 S at pH 8 and a molecular weight of about 280,000 as determined by high speed sedimentation equilibrium. Divergence between the number-, weight- and z- average molecular weights, and a sharp decrease of these values at low protein concentration, suggest that one is dealing with an associating-dissociating system.
Amino acid analysis revealed the presence of considerable quantities of carbohydrates in the enzyme. Colorimetric, gas chromatographic and enzymatic analyses demonstrated the presence of glucosamine, galactose, mannose, fucose and sialic acid residues in the ratio of 1:0.89:0.75: 0.13: 0.13, amounting to ca. 400 residues or 20% (56,000 daltons) of the molecular weight. With the exception of sialic acid, the carbohydrate content was remarkably constant from preparation to preparation.
Analyses by both atomic absorption spectrometry and the dithizone method showed that zinc–the only metal found in significant amount–was always present in the ratio of 2 atoms per molecule. It is therefore proposed that pig kidney particulate aminopeptidase is a Zn-containing glycoportein.
TL;DR: The lack of hybrid formation after separate incubation, suggests that the equilibrium in this case must be shifted to the associated state, while high hydrostatic pressure favours hybrid formation, while the coenzyme (NAD and NADH) or glycine inhibit dissociation as well as hybridization.
Abstract: Lactic dehydrogenase from pig heart isoenzyme (H4) and skeletal muscle (isoenzyme M4), under solvent conditions comparable to conditions in vivo, represents a stable, monodisperse tetramer. Solvent conditions which favour subunit dissociation on principle affect the native conformation of the enzyme leading to (partial) deactivation.
In the case of pH-dependent dissociation, the breakdown of the quaternary structure is preceded by deactivation. The action of high electrolyte concentration depends on the ions applied to the enzyme, deactivation following the lyotropic series of ions. Dissociation (hybridization) is promoted only by weak-structure-breaking ions, strong-structure breakers leading to irreversible denaturation and aggregation. Medium electrolyte concentrations cause preferential hydration rather than dissociation. The separation of dissociation from hybrid equilibration by incubating isoenzymes H4 and M4 together or in two separate probes, proves that high salt concentration (e.q. 2 M LiCl) fully dissociates the isoenzymes. Both experiments provide identical patterns for all hybrids. Low salt concentration (e.g. 0.005 M citrate) requires low enzyme concentration and increased temperature to produce subunit dissociation. The lack of hybrid formation after separate incubation, suggests that the equilibrium in this case must be shifted to the associated state. High hydrostatic pressure favours hybrid formation, while the coenzyme (NAD and NADH) or glycine inhibit dissociation as well as hybridization.
At low protein concentration, under medium conditions of the enzymic assay, no indication of subunit dissociation was observed.
TL;DR: Viability was superior for males receiving the diets containing 8.9 or 5.1 per cent protein, and the low protein diets had no adverse effects on semen production, fertility or hatchability following recovery from the protein restriction.
Abstract: Synopsis Two experiments were conducted to determine the effects of delaying sexual maturity of broiler breeder males on subsequent reproductive performance. Four dietary protein levels (16.0, 12.4, 8.9 and 5.1 per cent) were fed during the growing period. Thereafter, all males were fed a diet containing 17.0 per cent protein. Sexual maturity was delayed 4 and 8 weeks, respectively, by feeding the 8.9 and 5.1 per cent protein diets, but was not affected by feeding the 12.4 per cent protein diet. Viability was superior for males receiving the diets containing 8.9 or 5.1 per cent protein. The low protein diets had no adverse effects on semen production, fertility or hatchability following recovery from the protein restriction.
TL;DR: Purine nucleoside phosphorylase from vegetative cells and spores of Bacillus cereus T was purified to electrophoretic homogeneity and revealed similar catalytic properties of both the spore and cell enzymes.
01 Jan 1971
TL;DR: The optimal feeding for the premature infant has yet to be defined and, in particular, the most advantageous intake of protein has been the subject of considerable investigation.
Abstract: The optimal feeding for the premature infant has yet to be defined and, in particular, the most advantageous intake of protein has been the subject of considerable investigation. Human milk with its low protein content was widely used and considered to be the feeding of choice until the studies of Gordon and Levine (I) indicated that premature infants, especially those with birth weights of under 1600 grams, gained weight more rapidly and retained more nitrogen when fed cow’s milk mixtures that contained a good deal more protein. These mixtures, however, also contained more minerals and several observers (2–4) suggested that the increased weight gain was the result of fluid retention. With greater appreciation of the strain of an increased solute load on the immature kidney, most recently there has been a tendency to feed a more moderate protein intake, in the range of 3 to 3.5 grams/kilogram/day.
TL;DR: Cell walls of three yeasts of the genus Rhodotorula grown in two different media permit the identification of glucosamine, galactose, glucose, mannose and fucose, whose structure seems to be more complex than the fractions isolated from cell walls of Saccharomyces.
Journal Article•
TL;DR: Two species of kangaroos had higher serum potassium levels than the other marsupials examined and the intracellular electrolytes showed considerably greater variation than in man and the potassium level was generally higher.
Abstract: 1. 1. Serum and intracellular RBC electrolytes were determined from a series of marsupials. Two species of kangaroos had higher serum potassium levels than the other marsupials examined. The intracellular electrolytes showed considerably greater variation than in man and the potassium level was generally higher. 2. 2. The organic constituents were similar throughout the marsupials although Perameles had low lipids and low ureas were found in Potorous . Isoodon had low protein bound iodine whereas a lactating female Sarcophilus had abnormally high values. The blood glucose and urea values are higher in marsupials than in humans. 3. 3. The serum proteins showed the absence of an α 1 -globulin. γ-Globulins were high in Lasiorhinus and Tachyglossus . 4. 4. Gas analysis data are given but are not different from human parameters. The enzymes all show a greater range than in humans and frequently are present in much greater quantities. Sarcophilus has very large amounts of acid phosphatase.
TL;DR: The effects of pH and low salt concentrations on the cold inactivation suggest that ionic bonds do play some role in subunit interactions, and the labilization of the protein by low concentrations of urea and the protection by high salt concentrations indicate the importance of hydrophobic bonds in the protein.
Abstract: Threonine deaminase from Rhodospirillum rubrum is subject to reversible cold inactivation at low protein concentrations. The inactivation appears to involve a dissociation of the native tetrameric protein to dimers. The standard free energy of dissociation at 0 °C was + 7.8 kcal/mole, while ΔS was—3.2 kcal/mole and ΔS was—41 entropy units. These values suggest that hydrophobic interactions are important in the maintenance of the tetrameric structure.
The labilization of the protein by low concentrations of urea and the protection by high salt concentrations also indicate the importance of hydrophobic bonds in the protein. However, the effects of pH and low salt concentrations on the cold inactivation suggest that ionic bonds do play some role in subunit interactions.
The normal allosteric modifier for threonine deaminase, l-isoleucine, protected the enzyme against cold inactivation. Although the R. rubrum enzyme is virtually insensitive to isoleucine inhibition, it is clear that this ligand can induce profound changes in the protein structure.
TL;DR: The in vitro determination of epoxidase correlates closely with the observation that low protein diets cause a reduction in toxicity of hepta chlor to weanling rats.
Abstract: Investigations of the influence of dietary protein level on the activity of hepatic microsomal epoxidase were undertaken to explain the effects of low protein diets on heptachlor toxicity. These studies showed that low protein diets resulted in lower levels of microsomal epoxidase when compared to controls fed adequate protein. The in vitro determination of epoxidase correlates closely with the observation that low protein diets cause a reduction in toxicity of hepta chlor to weanling rats. J. Nutr. 101: 9-12, 1971.
TL;DR: The higher egg weights and increased egg production achieved in this experiment by birds reared on the highest protein level and the reduction in food costs due to the use of the lower protein mashes were judged to be of only marginal economic significance.
Abstract: Synopsis An experiment was performed on about 200 birds of each of two commercial breeds from o to 392 d of age. Four treatments were applied from 40 to 134 d of age with any changes in the treatment occurring at 89 d of age. Three of the treatments consisted of variation in the degree of reduction in the crude protein content of the mash diets offered over this period: 15.9 per cent followed by 14.6 per cent; 14.6 per cent throughout; 14.6 per cent followed by 12.3 per cent. In the context of similar experiments reported in the literature the higher egg weights and increased egg production achieved in this experiment by birds reared on the highest protein level and the reduction in food costs due to the use of the lower protein mashes were judged to be of only marginal economic significance. The fourth treatment consisted of 14.6 per cent crude protein mash diet followed by only whole wheat consumed from 89 to 134 d of age. The saving in rearing food costs in this fourth group compared to the others was ...
TL;DR: A. negundo, thought by several workers to be the most distinct of the maples, was found to have relatively high protein similarity with the members of the section Saccharina, while A. rubrum and A. spicatum were shown to have the least protein similarity to the other taxa investigated.
Abstract: Seed proteins of seven taxa of Acer native to eastern North America were obtained by extraction in 2.5% saline buffer, pH 7.0. These were investigated using the techniques of polyacrylamide disc electrophoresis, immunoelectrophoresis, and double diffusion. Groupings indicated by our protein data were compared with groupings by other researchers based on morphological data. The members of the section Saccharina, A. saccharum subsp. saccharum, A. s. subsp. nigrum and A. s. subsp. floridanum, were found to have close protein similarity. A. negundo, thought by several workers to be the most distinct of the maples, was found to have relatively high protein similarity with the members of the section Saccharina. A. rubrum and A. spicatum were shown to have the least protein similarity to the other taxa investigated. There is low protein similarity between these two taxa, however, indicating they are divergent. The traditional placement of A. rubrum and A. saccharinum in the same section was supported by the rela...
TL;DR: The results suggest that a renal mechanism for urea excretion may control the plasma urea nitrogen concentration at about 30 mg/100 ml under certain conditions.
Abstract: Urea was infused into sheep both intravenously and intraruminally, and at several increasing rates. The infusions were continuous for at least 6 days for each quantity of urea infused. Three predominantly roughage rations were used. Two of these had the same roughage constituents; both had relatively low protein contents, but one contained starch. The amount of urea nitrogen retained in the body from the urea infused was greatest on the ration containing starch, when the nitrogen balance improved by as much as 4.3 g/day. The concentration of ammonia in the rumen increased linearly with the amount of urea infused by either route of administration, but was much higher in the sheep infused intraruminally. Plasma urea nitrogen concentrations increased linearly with each quantity of urea infused until they reached about 30 mg/100 ml. They increased above this concentration only in the sheep fed on the low protein roughage ration without starch. The results suggest that a renal mechanism for urea excretion may control the plasma urea nitrogen concentration at about 30 mg/100 ml under certain conditions.
TL;DR: The viscosity of solutions of calf thymus DNA is decreased after incubation with preparations of chick interferon of low protein content induced either by UV-inactivated NDV virus or by Polyinosonic:polycytidylic acid (poly I:C).
TL;DR: The results lead once again to the conclusion that the free αβ dimers show all the characteristic features of ligand binding to hemoglobin and indicate that even in the tetramer they may represent the fundamental unit of function.
TL;DR: The effects of prolonged pesticide feeding on operant conditioning and brain ChE and MAO activities of rats fed normal and low protein diets and neither ChE nor MAO of the rat brain were altered at the end of the training procedure.
Abstract: A study eas made of the effects of prolonged pesticide feeding on operant conditioning and brain ChE and MAO activities of rats fed normal and low protein diets. Four ppm of parathion in a 5% casein diet retarded the lever press performance and 1000 ppm Banol almost completely inhibited such responding in rats. These pesticides had no effect on the performance of the rats fed 18% casein diet. Neither ChE nor MAO of the rat brain were altered at the end of the training procedure. Other possible explanations for the changes in operant conditioning are discussed.
TL;DR: Hydrogenated marine fat and some other commercial fats were fed to young rats in a low protein diet at a level of about 50% of the calories, and the diet was marginal in choline, α -toco.
Abstract: Hydrogenated marine fat and some other commercial fats were fed to young rats in a low protein diet at a level of about 50% of the calories. The diet was marginal in choline, α -toco
TL;DR: The highest proteolytic activity was seen in the zone of comparatively low protein concentration, and in the course of this reaction an additional, highly active component and an inactive, low-molecular-weight fraction were formed.