Does carnosine possess direct antioxidant activity?

• 1.1. A brief review of development of ideas of the antioxidant activity of carnosine and related compounds is presented.
• 2.2. An analysis of the behaviour of carnosine in different models of free radical chain reactions shows that carnosine is a potent hydrophylic antioxidant of a direct non-enzymatic action.
• 3.3. It is characteristic of the higher activity of interaction with active hydroxyl radical.
• 4.4. However the known biological effects of carnosine cannot be explained only by its anti-oxidant properties.

     

Limited cleavage of human lactoferrin with pepsin

• 1.1. Human lactoferrin in the iron-saturated form was treated with pepsin at pH 3.0, and a fragment with a single iron-binding site was isolated in a 90% pure state.
• 2.2. Its mol. wt was near 33,000.
• 3.3. Its N-terminal residue was alanine, and its iron-binding properties were identical to those of lactoferrin.
• 4.4. The curve showing iron incorporation from lactoferrin and its fragment into reticulocytes showed a biphasic character.
• 5.5. It is concluded that lactoferrin consists of two largely independent parts, which may have arisen by a gene duplication process.

     

The enzymes of glutathione synthesis in erythrocytes from gsh-high and gsh-low type australian merino sheep

• 1.1. The activity of γ-glutamylcysteine synthetase and glutathione synthetase was determined in erythrocytes from Australian Merino sheep of different erythrocyte haemoglobin, potassium and GSH types.
• 2.2. The activity of γ-glutamylcysteine synthetase was diminished in GSH-low type erythrocytes, but glutathione synthetase had a similar activity in erythrocytes of both GSH types.
• 3.3. γ-Glutamylcysteine synthetase from erythrocytes of both GSH types was inhibited by physiological concentrations of GSH, but a greater inhibition of the enzyme from GSH-low type erythrocytes occurred at low GSH concentrations.

     

Seasonal variations in the antioxidant defence systems and lipid peroxidation of the digestive gland of mussels

• 1.1. The seasonal variations in the level of antioxidant compounds (glutathione (GSH), vitamin E, carotenoids) and in the activity of antioxidant enzymes, Superoxide dismutase (EC 1.15.1.1), catalase (EC 1.11.1.6), GSH-peroxidase (EC 1.11.1.9) in the digestive gland of mussels (Mytilus sp.) were evaluated. The lipid peroxidation process was also measured by determining the tissue concentration of malondialdehyde (MDA).
• 2.2. The physiological fluctuations of the antioxidant defence systems were inversely related to the accumulation of lipid peroxidation products (MDA) in the tissue. The observed seasonal variations are presumably related to the changing metabolic status of the animals, itself dependent on such factors as gonad ripening and food availability.
• 3.3. In particular, the obtained data indicate that a reduction of the antioxidant defence systems, occurring during winter, could be directly responsible for an enhanced susceptibility of mussels tissues to oxidative stress, as indicated by the high MDA concentration observed in this period.

     

The glycogen content in stressed marine bivalves: The initial absence of a decrease

• 1.1. Changes in the glycogen content, condition, stomach content and acetic acid concentration of mussels Mytilus edulis and cockles Cerastoderma edule were followed during periods of up to 14 days of exposure (to air) at temperatures of 5 and 20°C.
• 2.2. In animals with a high glycogen content the glycogen is not used during the first 3 to 7 days, at high and low temperature respectively.
• 3.3. After this latent period the glycogen concentration often decreased, coinciding with a high mortality and an increase of the concentration of acetic acid.
• 4.4. In cockles with a low glycogen content, and kept at a high temperature, glycogen can be used from the beginning of the stress period.
• 5.5. Between species no clear differences were found.
• 6.6. The stomach content decreased during exposure; however, the stomach content amounted to only 0.5 to 0.7% of the body weight, and is thought to be of minor importance as an energy source during the stress period.
• 7.7. Especially at the higher temperatures glycogen finally is transformed into acetic acid.
• 8.8. It is concluded that during exposure, the animals do not die because of a lack of energy reserves, but because of a high accumulation of acids.

     

Fermentation and the production of volatile fatty acids in the alimentary tract of the rock hyrax,Procavia capensis

• 1.1. Aspects of ruminant-like metabolism were examined in the hyrax Procavia capensis.
• 2.2. High concentrations of volatile fatty acids occurred in the cardiac stomach with a predominance of acetic and lactic acids.
• 3.3. Acetic (69%), propionic (22%) and butyric (8%) acids occurred in highest concentrations in the proximal caecum, with appreciable amounts in the proximal colon, distal caecum and appendices.
• 4.4. The depot fat contained high proportions of unsaturated C₁₈ (linoleic and linolenic) acids.
• 5.5. The glucose level in the plasma was within the range established for non-ruminant herbivores.
• 6.6. The possibility of silage-like fermentation occurring in the cardiac stomach is discussed.

     

Plasma lipid transport in the horse (Equus caballus)

• 1.1. Equine plasma contains lipoproteins corresponding to very low density (VLDL), low density (LDL) and high density lipoproteins (HDL).
• 2.2. HDL accounts for approximately 60% of plasma lipoprotein mass and consists of a single population of particles.
• 3.3. LDL is heterogeneous comprising three discrete subfractions.
• 4.4. Two proteins are found in the region of apolipoprotein (apo) B-100 in VLDL and LDL and a third similar to apo B-48 is in VLDL.
• 5.5. Lecithin:cholesterol acyl transferase is active in plasma and hepatic lipase and lipoprotein lipase are evident in post-heparin plasma.
• 6.6. There is no significant cholesteryl ester transfer protein activity.

     

The digestive proteases of langostilla (pleuroncodes planipes,decapoda): their partial characterization,and the effect of feed on their composition

• 1.1. Three methods of recuperating and preserving enzyme activity from freshly-caught langostilla were assessed. In the pressing and acetone extract methods, the recovered specific activity was similar.
• 2.2. Protease activity was higher between 6.5 and 8 pH, and was sensitive to high temperatures.
• 3.3. In PAGE and serine inhibition assays, one fraction resembled bovine trypsin.
• 4.4. The composition of proteins and molecules bearing protease activity from the hepatopancreas and stomach of both fed and starved animals was similar, indicating proteases are not induced but constitutive.

     

Oxidants and antioxidants in aquatic animals

• 1.1. Oxidative stress, potentially, is experienced by all aerobic life when antioxidant defenses are overcome by prooxidant forces, and is the basis of many physiological abberations.
• 2.2. Environmental contaminants may enhance oxidative stress in aquatic organisms, e.g. highly elevated rates of ideopathic lesions and neoplasia among fish inhabiting polluted environments is increasingly related to oxidative stress associated with environmental pollution.
• 3.3. Metabolism of redox cycling xenobiotics in aquatic organisms is very similar to that of mammals suggesting similarities in the health consequences of exposure to such compounds.
• 4.4. The expression of specific lesions known to arise specifically from oxidative stress, e.g. lipid peroxidation, oxidized bases in DNA and accumulation of lipofuscin pigments are present in many aquatic animals exposed to contaminants.
• 5.5. Aquatic organisms contain the major antioxidant enzymes SOD, catalase and glutathione peroxidase, albeit there are marked quantitative differences among the various species reported.

     

Plasma lipoprotein profiles and arylesterase activities in two inbred strains of rabbits with high or low response of plasma cholesterol to dietary cholesterol

• 1.1. Cholesterol feeding for 4 weeks of female and male rabbits of two inbred strains increased plasma cholesterol concentrations by about 11 and 48 mmole/I in the hypo- and hyperresponsive strain, respectively.
• 2.2. On the low-cholesterol pre-experimental diet, the hyporesponsive animals had significantly higher plasma HDL (high density protein) cholesterol levels than hyperresponders.
• 3.3. In both strains, cholesterol feeding caused elevations of cholesterol in all lipoprotein classes, the difference between the hypo- and hyperresponsive strains in essence only being observed in the VLDL (very low density lipoprotein) fraction.
• 4.4. Basal plasma total arylesterase activity was significantly higher in the hypo- than in the hyperresponsive rabbits.
• 5.5. Dietary cholesterol caused an increase in plasma esterase activity in both strains.
• 6.6. We suggest that in rabbits a low plasma arylesterase activity and a low concentration of HDL cholesterol are associated with an increased sensitivity to dietary cholesterol.

     

Environmental cues influencing the breeding biology and circulating levels of various hormones and triglycerides in the cape cormorant

• 1.1. Phalacrocorax capensis shows a well-demarcated summer breeding season. During this season gonadal weights, plasma levels of testosterone and luteinizing hormone are at peak levels.
• 2.2. Plasma levels of circulating triglycerides and weight of stomach contents are also at their highest level during summer but body weight and fat index decline progressively during the breeding season.
• 3.3. Although sexual activity is uniformly high during the summer breeding season, sexual activity of males precedes that of the females and two distinct peaks of activity occur within the breeding season which appear to be associated with the abundance, condition and reproductive activity of the main food item, namely pilchards.
• 4.4. An analysis of the various environmental cues responsible for controlling the breeding season of P. capensis has been attempted.

     

Effects of photoperiod on plasma corticoid levels in the goldfish,Carassius auratus—role of the pineal

• 1.1. The effects of photoperiod and pinealectomy on plasma corticoid levels in the goldfish (Carassius auratus) were examined.
• 2.2. Plasma corticoid levels differed in goldfish maintained under different photoperiod regimes, but this response varied seasonally.
• 3.3. Pinealectomy altered the effects of photoperiod on plasma corticoid levels but this effect varied with season.
• 4.4. Plasma corticoid levels were correlated with ovarian activity. The effects of photoperiod on plasma corticoid levels appear to be related to the influence of light on reproduction.
• 5.5. The alteration of plasma corticoid levels in pinealectomized fish may be due to the role this organ plays in mediating photoperiod effects on gonadal activity.

     

The effect of feed restriction on certain haematological indices,enzymes and metabolites in Nubian goats

• 1.1. Some effects of restricting feed intake for 96 or 168 hr were determined in male Nubian goats.
• 2.2. Goats restricted for 96 hr lost 11.6% of their body weight, and goats restricted for 168 hr lost 19.8%.
• 3.3. Feed restriction for up to 168 hr did not produce significant effects on the heart rate, respiratory rate or rectal temperature.
• 4.4. Haemoglobin concentration, packed cell volume and erythrocyte number were all decreased by feed restriction. There was also a tendency towards eosinopenia and lymphopenia.
• 5.5. Feed restriction for 96 or 168 hr raised the plasma activity of aspartate transaminase, and did not affect significantly cholinesterase activity. Plasma amine oxidase activity was significantly reduced in goats restricted for 168 hr.
• 6.6. Feed restriction produced significant increases in the blood or plasma concentrations of lactate. pyruvate, non-esterified fatty acids, cholesterol, ketone bodies and bilirubin.
• 7.7. Significant decreases were found in the concentrations of total protein and calcium.
• 8.8. No significant changes were observed in the plasma concentrations of glucose, sodium or potassium.

     

The effect of egg-shell calcification on the response of plasma calcium activity to parathyroid hormone and calcitonin in the domestic fowl (Gallus domesticus)

• 1.1. The effects of Parathyroid Hormone and Calcitonin on the concentrations of ionised calcium, total calcium and phosphorus in the plasma of laying hens with and without a calcifying egg in the oviduct, were studied.
• 2.2. Parathyroid Hormone led to an increase in the plasma calcium activity in both groups of hens, but in non-egg calcifying birds this was preceded by a transient reduction in activity.
• 3.3. Calcitonin reduced the plasma calcium activity in non-egg calcifying birds but not in egg calcifying birds.
• 4.4. The significance of these effects in relation to the availability of bone calcium for shell production is discussed.

     

Electrolyte changes,cell volume regulation and hormonal influences during acclimation of rainbow trout (Salmo gairdnerii) to salt water

• 1.1. Rainbow trout were acclimated to salt water (1.5, 2.0 or 3.0%, which means 40, 60 or 85% concentrated sea-water) and the electrolyte, glucose and cortisol concentrations of the plasma as well as the extra- and intracellular muscle space, the muscle electrolyte concentrations and the ATPase activity were analysed.
• 2.2. Plasma osmolality, Na⁺, Ca²⁺ and Mg²⁺ concentrations of the plasma had a maximum at 24 hr after the start of acclimation when acclimated to 3.0% salt water. Plasma osmolality, Na⁺ and Mg²⁺ concentrations were significantly higher during the whole acclimation time when exposed to 3.0% salt water.
• 3.3. Variations and regulations of ECS and ICS were clearly demonstrated. The intracellular electrolyte concentrations were also maximal at 24 hr.
• 4.4. The plasma glucose level was just slightly elevated, but the cortisol level clearly indicated a stress response at 24 hr.
• 5.5. The activity of gill Na-K-ATPase increased during the acclimation time.
• 6.6. The regulatory processes in trout during acclimation to salt water are compared with those occurring in tilapia and carp.

     

Influence of handling and/or anaesthesia on stress response in rainbow trout. Effects on liver primary metabolism

• 1.1. The overall effect of handling, anaesthesia and sham injection on some blood metabolites, liver glycogen and several key enzymes involved in liver carbohydrates and nitrogen metabolism was studied in rainbow trout. In addition, the possible role of anaesthesia (MS222) itself as a stress-inductor or suppressor was also studied.
• 2.2. Stress resulted in hyperglycaemia and initially in liver glycogen depletion, as well as increasing plasma amino acid levels.
• 3.3. Glycogen stores subsequently recovered while amino acid concentration fell.
• 4.4. These changes seemed to correlate with the increased activity of liver fructose 1,6-bisphosphatase, glucose 6-phosphate dehydrogenase, alanine aminotransferase and glutamate dehydrogenase, thus supporting the hypothesis that gluconeogenic flux from amino acids increases in stressed trouts.
• 5.5. Anaesthesia, under the same experimental conditions, did not seem to mediate in stress production, but rather resulted in stress suppression.

     

Effect of developmental derangements on the proteolytic and protease-inhibitory activities in Galleria mellonella (Insecta)

• 1.1. Protease inhibitory activity in the whole body homogenates of Galleria mellonella larvae exhibits maxima at the beginning of the last larval and pupal instars. Injury, chilling, immobilization, and ligations of larvae cause an increase of inhibition.
• 2.2. The inhibitory activity is high in the haemolymph but low in midgut and faty body. By contrast, the proteolytic activity is low in haemolymph and high in both midgut and fat body.
• 3.3. Starvation and ligations cause a dramatic fall of the proteolytic activity and increase of the inhibitory activity in examined organs.

     

Flight effects on certain blood parameters in homing pigeons Columba livia

• 1.1. Various blood parameters were monitored in resting and flown homing pigeons. A homing flight of 48 km lasting 60–80 min did not significantly alter plasma levels of total protein, electrolytes and plasma osmolality, which indicated maintenance of the homeostatic stability of the internal milieu during moderate exercise.
• 2.2. Plasma concentrations of marker enzymes such as alanine aminotransferase (ALAT), aspartate aminotransferase (ASAT), laetate dehydrogenase (LDH) and creatine phosphokinase (CPK) that tend to denote muscle damage and metabolic flux in prolonged exercise, were also not altered, thereby indicating the steady state of tissue structure and function during a flight of this magnitude.
• 3.3. Significant increases in plasma levels of uric acid and creatinine and decreases in plasma albumin were observed in the flown pigeons.
• 4.4. The flight-induced increase in blood uric acid could be attributed to increased purine catabolism and the increase in creatinine to increased nucleotide turnover.
• 5.5. It is suggested that the higher uric acid levels should not only enhance water conservation, but may also reduce flight-induced hyperthermia besides acting as an antioxidant defence against oxidative tissue injury.
• 6.6. The rise in creatinine is indicative of the breakdown of phosphocreatine for energy during the initial period of flight prior to the utilization of carbohydrate and lipid as fuels.
• 7.7. The decrease in plasma albumin should account for the albumin as lipid carrier lost in transport to the muscles during flight.

     

Factors influencing lipid levels and lecithin:cholesterol acyltransfer in plasma of the lizard,Tropidurus torquatos

• 1.1. Lipid concentrations and lecithin:cholesterol acyltransferase (LCAT) activity in the plasma Tropidurus torquatos were remarkably variable.
• 2.2. Both lipid levels and LCAT activity were highest for lizards collected during the early rainy season (March–April) than during other seasons, and were higher for females than for males.
• 3.3. Plasma lipid levels and LCAT activity were significantly and inversely correlated with body weight (age) of male lizards, this being associated with an apparent change to an herbivorous diet in older males.
• 4.4. During prolonged fasting, plasma lipid levels and lecithin:cholesterol acyltransfer (LCAT) and hepatic phospholipids were markedly reduced.
• 5.5. LCAT activity in plasma of fasted and non-fated lizards was significantly correlated with the molar proportion of PC to UC, suggesting that the apparent low LCAT in plasma of fasted lizards is partly due to depletion of PC in the lipoprotein substrates.

     

Are egg yolk lipoproteins metabolized by the chick embryo in the same manner as plasma lipoproteins are in the adult?

• 1.1. Egg yolk very low density lipoproteins were found to contain proteins with cofactor activity for lipoprotein lipase.
• 2.2. Lipoprotein lipase activity in adipose tissue of chick embryos increased several-fold on days 16 and 17, coinciding with the time when utilization of yolk lipoproteins by the embryo becomes rapid.
• 3.3. Embryonic blood plasma was found to contain cholesterol esterifying activity.