Specific dynamic action (SDA) in the supralittoral isopod,Ligia pallasii: Identification of components of apparent SDA and effects of dietary amino acid quality and content on SDA

• 1.1. Specific Dynamic Action (SDA) effects of diet were investigated in the supralittoral isopod, Ligia pallasii, using defined chemical diets.
• 2.2. “Apparent SDA”, or the total rise in metabolic rate following a meal, was resolved in animals eating a nutritionally complete chemical diet into three components: 8% mechanical costs of moving food through the gut, 40% “excitement costs” due to investigator disturbance and presence of food, and 52% SDA.
• 3.3. Excitement costs in animals exposed to food but which chose not to eat showed non-significant variation between diets containing different levels of chemical nutrients, but were significantly less on a diet containing only cellulose and agar.
• 4.4. SDA increased with increasing concentration of amino acids in the diet.
• 5.5. Substitution of whole-protein casein for free amino acids in the diet had no significant SDA effect, while substitution of free amino acids in the ratio found in casein more than doubled the SDA effect.
• 6.6. Deletion of alanine from the diet caused no significant effect on SDA, while deletion of phenylalanine caused a highly significant elevation in SDA.

     

The effect of pyridoxine deficiency on aminotransferase activity in liver and white muscle of rainbow trout (Salmo gairdneri Richardson)

• 1.1. Aspartate aminotransferase activity in the white muscle of rainbow trout dropped significantly after the animals had received a pyridoxine-deficient diet for 7 days.
• 2.2. Alanine aminotransferase activity in the white muscle of rainbow trout dropped significantly after the animals had been fed on a pyridoxine-deficient diet for 21 days.
• 3.3. Alanine and aspartate aminotransferase activity in the liver of rainbow trout did not drop significantly until the animals had received a pyridoxine-deficient diet for 28 days.
• 4.4. After rainbow trout have received a pyridoxine-deficient diet for 35 days, feeding with complete diet for 7 days is sufficient to restore the aminotransferase activities to the levels observed in control animals.

     

Specific dynamic action (SDA) in the supralittoral isopod,Ligia pallasii: Relationship of growth to SDA

• 1.1. The relationship of Specific Dynamic Action (SDA) to growth was examined in the supralittoral isopod Ligia pallasii using a seaweed diet fed at different rations.
• 2.2. Animals increased in live weight by 33% on an ad libitum or 100% diet and by 2% on a 20% ration over a 10-week period.
• 3.3. Weight-specific VO₂ was significantly higher in animals eating the 100% diet than in ones eating the 20% diet. Decline in VO₂ with time in animals on the 20% diet was probably due to poor health associated with a maintenance ration.
• 4.4. SDA per unit weight of food eaten was 18% higher in the 20% diet group than in the 100% one, and values remained constant over time in both groups.
• 5.5. k₁ growth efficiencies (production/consumption) were higher in animals on 100% ration than in ones on 20% ration. Efficiencies declined with time in both diet-groups and fell below zero in the 20% ration-group, coincidental with weight-loss in some of the animals.
• 6.6. Overall SDAs for the 10-week period were positively correlated with growth (r₂ = 0.77), but there was no way to separate this from amounts eaten as an effect on SDA.

     

Blood changes in japanese eels,Anguilla japonica,experimentally infected with typical or atypicalAeromonas salmonicida

• 1.1. Changes in the blood and in the rate of oxygen consumption of Japanese eels injected intramuscularly in the head with a lethal dose of typical or atypical Aeromonas salmonicida at 20°C were investigated.
• 2.2. Eels infected with the bacteria became moribund within 4 to 6 days, and then died within 1 day.
• 3.3. The O₂ consumption rate and blood parameters changed markedly with infections. The responses of hosts to infection by the two kinds of bacteria differed with regard to the following four points: blood pH, plasma Cl⁻, lactic acid, and the numbers of granulocytes and lymphocytes.
• 4.4. The responses of eels infected with atypical A. salmonicida were larger and more rapid than those of eels infected with typical A. salmonicida.

     

Entomopathogenic fungal infection (Deuteromycotina: Hyphomycetes) affects water relations of the german cockroach,Blattella germanica (L.) (Dictyoptera: Blattellidae)

• 1.1. The total body water, lipid content, and cuticular permeability of fungus infected and uninfected German cockroaches, Blattella germanica, were examined.
• 2.2. Infected adult cockroaches weighed less and had significantly more body water than did uninfected specimens of the same size.
• 3.3. Uninfected medium-size nymphs weighed significantly more than infected nymphs, but there was no difference in body size between infected and uninfected small nymphs.
• 4.4. Cuticular permeability and lipid content of infected and uninfected cockroaches was not significantly different.
• 5.5. Sequestering of water by the fungal cells is discussed as a possible factor in the pathology of this fungal parasite.

     

Studies on the nutrition of the supralittoral isopod Ligia pallasii using chemically defined artificial diets: Assessment of vitamin,carbohydrate, fatty acid,cholesterol and mineral requirements

• 1.1. An artificial diet, consisting of a dry aggregate of 59 chemical substances, was used to assess the requirements of the sea slater Ligia pallasii for vitamins, carbohydrates, fatty acids, cholesterol and minerals.
• 2.2. Good growth and survival of L. pallasii was obtained on the diet, comparable to that on seaweeds and to that shown by a field population.
• 3.3. No dietary requirements for vitamins, fatty acids or cholesterol were shown for periods of 40 weeks or more for L. pallasii.
• 4.4. Carbohydrates were shown to be required by L. pallasii in its diet, in the order: starch, lactose > maltose, glucose > sucrose, cellulose.
• 5.5. Dietary requirements for minerals were, in order: calcium, magnesium, phosphorus > copper, nickel, zinc > iron, manganese, sulphur > iodine, silicon.
• 6.6. The results are discussed in relation to the role of gut bacteria in supplying required nutrients to their isopod hosts and the enhancement of this process through coprophagic behaviour.

     

The effects of cholesterol feeding on the membranes of liver cells and on the cholesterol metabolism in the rat

• 1.1. Feeding of rats with a 2% cholesterol diet for 6 weeks increased the serum cholesterol concentration. The activity of lecithin cholesterol acyltransferase was also increased during the feeding time.
• 2.2. The activities of aspartate aminotransferase and alanine aminotransferase remained on a constant level during the experiment on rats having cholesterol in their diet. Omitting cholesterol from the diet enhanced the activities of both enzymes and the increase in alanine aminotransferase activity was more pronounced.
• 3.3. The activity of alkaline phosphatase was on higher level during the whole experiment in the rats having cholesterol in the diet than in those fed a cholesterol-free diet.
• 4.4. Present data suggest that excluding cholesterol from the diet labilizes the membranes of hepatocytes and facilitates the release of aspartate and alanine aminotransferases in the blood.

     

Growth and hemolymph trehalose levels of Heliothis zea larvae fed diets containing various sugars

• 1.1. The amount of sugar required for growth of Heliothis zea larvae on a chemically defined diet was determined.
• 2.2. Larvae grew well on fructose, galactose, sucrose, trehalose and raffinose diets but not on diets containing more than 0.5% glucose.
• 3.3. A starch diet did not promote rapid larval growth.
• 4.4. Hemolymph trehalose levels in 12-day-old larvae ranged from none to 45μmoles/ml.
• 5.5. A method for analysis of hemolymph trehalose by gas chromatography is described.

     

Oxygen uptake by Trypanosoma lewisi complex cells—III. C isolate

• 1.1. Standard Warburg techniques were employed to determine the oxygen uptake of two isolates (C and L) of Trypanosoma lewisi (Costa Rican and the U.S.). The C cell developed greater parasitemias in rat tail blood during the first 2 weeks after inoculation.
• 2.2. Oxygen uptake of both isolates progressively increased with time and was not related to rise in trypanosome populations in hosts. The C form (recently isolated) consumed 36 per cent more oxygen endogenously, 20 per cent more in glucose and 16 per cent more in serum than the L.
• 3.3. The metabolic capacity (Max./initial Q_O2) of the C cell was greater endogenously and in glucose; the L was superior in serum. Efficiency (substrate Q_O2 ratios) of the L cell was superior.

     

Running performance of the thirteen-lined ground squirrel,the eastern chipmunk and the albino Norway rat

• 1.1. The procedure used to compare the forced running performance of three rodent species was the number of electrical stimuli required each minute to keep the animals running.
• 2.2. During running trials, ground squirrels, Spermophilus tridecemlineatus, required fewer stimuli than white rats. Squirrels ran 12.4 ± 6.9 (2 SE) min before requiring stimulation vs 3.1 ± 1.4 min for rats.
• 3.3. Total oxygen consumption during the running period was significantly higher for ground squirrels than white rats, 4.70 ± 0.36 and 4.18 ± 0.38ml O₂/g/hr, respectively.
• 4.4. Heart weight/body weight ratios were significantly higher for the ground squirrels than the white rats.
• 5.5. No differences were noted between ground squirrels and chipmunks other than those which could be accounted for by body weight differences.

     

1H NMR study of metabolic alterations in the small intestine of rats infected with Hymenolepis diminuta

• 1.1. 1H NMR spectra of the duodenum, jejunum and ileum tissues of the small intestine of a rat showed metabolic gradients.
• 2.2. The concentrations of metabolites in these gut regions were altered by the presence of the tapeworm Hymenolepis diminuta.
• 3.3. In the infected duodenum there was significantly less glycogen, glucose and phosphocreatine/creatine, but significantly more lactate than in the corresponding controls.
• 4.4. Infected jejunum contained significantly less betaine but significantly more succinate, alanine and lactate.
• 5.5. Infected ileum had significantly less glycogen and taurine but significantly more alanine and lactate.

     

Studies on the active centre(s) of rat liver porphyrinogen carboxy-lyase. in vivo effect of hexachlorobenzene on decarboxylation site(s) of porphyrinogens

• 1.1. The role of histidine on the decarboxylation of porphyrinogens of 7-, 6-, and 5-COOH III brought about by porphyrinogen carboxy-lyase (PCL) was studied.
• 2.2. For this purpose hepatic PCL from normal and hexachlorobenzene (HCB) treated rats were modified with diethylpyrocarbonate.
• 3.3. The results indicated that the enzyme from both normal and porphyric animals had histidine at the binding sites of all the porphyrinogens assayed.
• 4.4. Comparative studies between the enzyme from normal and porphyric rats suggested that in vivo HCB treatment affected the active site for the decarboxylation of 7-, 6- and 5-COOH porphyrinogens III at histidine residues.
• 5.5. On the other hand arginine modification by 2,3-butanedione treatment altered 5-COOH porphyrinogen III decarboxylation for both enzymes. However this amino acid was not involved at the binding site of this substrate.

     

Proline in fascioliasis—IV induction of bile duct hyperplasia

• 1.1. Rats were implanted with cannulae in the abdominal cavity and infused with one of the following solutions: saline; 20.0 mM proline in saline, or saline containing alanine, valine, methionine, leucine, tyrosine, phenylalanine and histidine each at 2.0 mM.
• 2.2. Comparison of the lumenal perimeters in the bile ducts of the infused animals revealed that a significant hyperplasia was induced by proline; none of the other amino acids tested was effective.
• 3.3. Histologically, the proline-induced hyperplasia resembles that observed in bile ducts from rats infected with Fasciola hepatica.

     

Myofibril and sarcoplasmic reticulum changes during muscle development: Activity vs inactivity

• 1.1. The purpose of this study was to determine whether biochemical changes of skeletal muscle that occur as a result of exercise in young rats persist into adulthood.
• 2.2. Littermates (10 days old) were assigned to a 3, 6 and 12 week control or training group. In addition, a rest-exercise group (R-E) and exercise-rest (E-R) group were included.
• 3.3. The rest-exercise and exercise-rest rats were maintained for the 12 weeks with the first 6 weeks being either rest or exercise and the condition reversed during the last 6 weeks of the experiment.
• 4.4. Myofibril ATPase activity of rat plantaris increased from the 10d to 12 week animals (P < 0.05). As anticipated, training resulted in a lowered activity at 6 and 12 weeks compared to controls.
• 5.5. The Ca²⁺ uptake and Ca²⁺-ATPase activity of the sarcoplasmic reticulum followed a similar pattern.
• 6.6. With regard to the exercise-rest rats, the myofibril and SR ATPase activities at 12 weeks were comparable to the 12 weeks control rats.
• 7.7. The rest-exercise group approximated the 12 week training group with regard to myofibril and SR ATPase activities (P > 0.05).
• 8.8. The results suggest that the training adaptations that occur during development of skeletal muscle return to normal, when training ceases in the adult rat.
• 9.9. Furthermore, animals that started to train prior to puberty do not have a greater capacity to adapt than animals which initiated training during adulthood.

     

Effects of starvation and a carbohydrate-rich diet on glycogen metabolism in a gastropod mollusc,Megalobulimus oblongus

• 1.1. Administration of a carbohydrate-rich diet increased haemolymph glucose levels and glycogen concentration in hepatopancreas, mantle and muscle.
• 2.2. Glycogen concentration in tissues decreases after 2 weeks of starvation and haemolymph glucose levels did not change significantly.
• 3.3. However, starvation did not induce a decrease in the intrinsic synthetic capacity in tissues.
• 4.4. Glycogen synthesis in tissues from animals fed with lettuce or a carbohydrate-rich diet, increases with increasing glucose concentration in the media.
• 5.5. However, in mantle slices from snails adapted on a carbohydrate-rich diet, the glycogen synthetic capacity was lower than in slices from snails fed with lettuce.

     

Adaptive changes in total pyruvate dehydrogenase activity in lipogenic tissues of rats fed high-sucrose or high-fat diets

• 1.1. Pyruvate dehydrogenase complex (PDC) activity was measured in several tissues of rats fed for 7 or 15 days on control, or high-sucrose or high-fat diets.
• 2.2. Total activity in adipose tissue increased in the three groups 3–4-fold as compared with chow-fed animals in the first week. Total activity was 60% lower in rats fed the diet containing 22% corn oil for 2 weeks.
• 3.3. Hepatic total and PDCa activities were 50–80% higher in rats fed the sucrose diet for 7 or 15 days and decreased 30–40% in those fed on the high-fat diet for 2 weeks.

     

Differential post-receptor responses of adenylate cyclase in white and brown adipose tissue membranes of rats fed high-energy diets

• 1.1. Adenylate cyclase activity was determined in membranes of white and brown adipose tissue (WAT and BAT, respectively) from rats fed a high-energy diet (EXP group) vs those fed a nutritionally balanced one (CON group).
• 2.2. The isoproterenol- and guanine nucleotide-induced adenylate cyclase activity in WAT membranes of EXP rats was lower than that in CON rats.
• 3.3. Relative adenylate cyclase activity in like treated BAT membranes was higher in EXP than in CON rats.
• 4.4. It is concluded that feeding high-energy diets to rats induces similar post-receptor modifications of adenylate cyclase as found in genetic obese rodents.

     

A comparison of aspartate transcarbamylase activity in juvenile pacific oysters (Crassostrea gigas) when fed various diets

• 1.1. The optimum pH for measurement of aspartate transcarbamylase activity in oyster tissue was determined to be 9.35 while the optimum temperature was 39.5°C.
• 2.2. Aspartate transcarbamylase activity varied significantly over short periods of time (hr) possibly due to fluctuations in the amount of food digested.
• 3.3. The composition of the oyster's diet also affected the levels of aspartate transcarbamylase activity in oyster tissues.
• 4.4. Those oysters fed an egg yolk-starch diet contained significantly lower aspartate transcarbamylase activity than oysters fed an egg yolk-starch-salmon oil diet or a casein-starch-salmon oil diet.
• 5.5. The aspartate transcarbamylase activities in oysters fed Phacedactylum tricornutum or a starch diet were not significantly different from the activities in oysters fed the egg yolk-starch diet.

     

Impaired microtubule assembly in brain from zinc-deficient pigs and rats

• 1.1. Microtubule reassembly was studied in brain extracts from pigs and rats deficient in zinc and from zinc-supplemented controls. Tubulin in extracts from zinc-deficient animals showed an impaired ability to repolymerize compared with extracts from control animals.
• 2.2. Crude microtubule protein isolated from zinc-deficient rat brain contained less free SH groups than that isolated from zinc-supplemented animals.
• 3.3. It is concluded that variation in zinc concentration close to the physiological range can influence microtubule assembly, and that zinc may have some function in microtubule polymerization in vivo.

     

Cardiac responses of larval and adult tiger salamanders to submergence and emergence

• 1.1. The ECG of aquatic Amhystoma tigrinum from the Colorado Rocky Mountains was recorded while the animals submerged and emerged in water. Older larvae and metamorphosed adults were compared.
• 2.2. Free-swimming animals of both types showed slight emergence tachycardia when taking a “gulp” of air.
• 3.3. Preventing access to air for 30 min or more resulted in a slight bradycardia in larvae. Some adults responded with increased, others with decreased, heart rate depending on their level of excitement.
• 4.4. Restraining the animals before forced submergence caused a greater bradycardia than when unrestrained.
• 5.5. Low dissolved oxygen accentuated the cardiac responses of larvae to submergence but not in adults.
• 6.6. Atropine only partially blocked the diving responses of both forms.
• 7.7. The degree of submergence bradycardia seems to be a function of the ability to extract oxygen from water. It probably is not an adaptation to diving in these forms. Instead the submerged heart rate in these predominantly aquatic salamanders may be the “normal” rate with emergence tachycardias for breaths of air.