Effect of starvation and sea-water acclimation on the concentration of free l-histidine and related dipeptides in the muscle of eel,rainbow trout and Japanese dace

• 1.1. During the starvation of the eel (200 days), the rainbow trout (62 days) and the Japanese dace (75 days), white muscle free l-histidine decreased rapidly in every species, while carnosine and anserine levels in the eel and trout, respectively, exhibited relatively smaller percentage changes.
• 2.2. Accompanying sea-water acclimation, l-histidine in skeletal muscle of the ell and trout increased 2- and 5-fold, respectively, but in dace muscle no significant chenge occured. The concentration of carnosine in the eel and anserine in the trout remained almost at constant levels even in sea-water.

     

The high intracellular ph buffering of hagfish (Eptatretus cirrhatus) dental plate retractor muscle cannot be attributed to the known histidine-related compounds present in other vertebrates

• 1.1. Intracellular pH buffering capacity of hagfish (Eplatretus cirrhatus) dental plate retractor muscles is among the highest reported for any vertebrate muscle.
• 2.2. Over 80% of the pH buffering capacity of hagfish retractor and myotome muscle is due to components other than proteins and phosphate.
• 3.3. The muscles have less than 0.5 μmol/g wet weight of l-histidine, and lack l-l-methyl histidine, l-3-methyl histidine and the histidine-containing dipeptides anserine, carnosine and ophidine.
• 4.4. Instead, they contain an unidentified low molecular weight acid-soluble compound to which the high pH buffering capacity can be attributed.

     

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.

     

Human urinary excretion of l-histidine-related compounds after ingestion of several meats and fish muscle

• 1.1. After oral administration of the muscle of skipjack tuna, about 90% of ingested anserine (Ans) was excreted quickly into urine as Ans (8%) and π-methylHis (82%), indicating the fast decomposition of Ans into π-methylHis. This was also the case for chicken muscle ingestion.
• 2.2. After eel muscle ingestion, carnosine (Car) excretion was only 1 % of the ingested whereas almost no increase was found in His, a constituent of Car, indicating the re-utilization of this essential amino acid. Similar results were also obtained from beef and pork ingestion.
• 3.3. In all cases, the urinary excretion of these compounds reached a maximum within 7 hr after ingestion and returned to the level of meat-free diet within 40 hr.

     

Chemical characterization of the brain of a coelacanth,Latimeria chalumnae

• 1.1. The chemical composition of coelacanth brain was studied and compared with some other species of bony fishes.
• 2.2. Almost all lipid classes generally seen in vertebrate brains were detected: 22:1 and 22h:1 acids were abundant in cerebroside and 24:1 acid in ganglioside. The hydroxy fatty acid content of cerebroside was high.
• 3.3. The myelin protein composition was unusual in that a 28,000-dalton protein was a major component.
• 4.4. 2′,3′-Cyclic nucleotide 3′-phosphodiesterase was 10 times more active than in the other bony fishes.
• 5.5. The present data suggest that molecular construction of coelacanth myelin is more advanced than that of the other bony fishes.

     

Study of the heme catabolism of fish

• 1.1. The composition of bile pigments in the blood and bile of 39 species were studied.
• 2.2. Conjugated bilirubin (trace to 4.62 mg/100 ml) was detected in the serum of most fish, while biliverdin (trace to 2.0 mg/100ml) was detected only in Anguilla Japonica, Thalassoma lunare and Clinocottus analis.
• 3.3. Analysis showed tht there are two types of bile pigments excretion pattern in these fishes. The first pattern excretes bilirubin (most conjugate) predominantly, the other excretes mostly biliverdin with some bilirubin. However, during starvation, the excretion of conjugate bilirubin gradually shifted to unconjugated biliverdin. The rate of shifting varies with species.
• 4.4. Introduction of bilirubin into Anguilla japonica produced an initial excretion of mono-conjugates, followed by di-conjugates. Introduction of biliverdin caused an increased in the excretion of unconjugated biliverdin, but no significant increase of bilirubin in the bile was detected.
• 5.5. A binary excretion pathway of bile pigments in fish is proposed. The evolutionary characteristics of heme catabolism in terrestrial animals with respect to this pathway is discussed.

     

Renin-angiotensin system in antarctic fishes

• 1.1. The presence of a renin-angiotensin-like system has been investigated in the Antarctic fishes Chionodraco hamatus (Fam. Channichthydae) and Pagothenia (Trematomus) bernacchii (Fam. Notothenidae).
• 2.2. A renin-like activity is present in plasma and kidney of both the white blooded (Chionodraco) and the red blooded (Pagothenia) species.
• 3.3. An angiotensin converting enzyme-like activity has been demonstrated in plasma, gills and kidneys of both species. The activity is inhibited by high temperature.
• 4.4. From our data a renin-angiotensin-like system is present in the Antarctic fishes studied but the cascade of enzymes is active only at low temperatures.

     

The influence of biochemical species differences on acute fish toxicity of organic chemicals

• 1.1. Reported lc₅₀s of hundreds of chemicals and data of many enzymes in many fishes have been reviewed in order to find the hypothesized influence of biotransformation on acute toxicity.
• 2.2. Biotransformation of carbaryl was correlated and biotransformation of endrin was inversely correlated with acute toxicity.
• 3.3. For most compounds no correlation was found which indicates that either biotransformation is not important in acute toxicity or enzyme activities are not representative parameters to quantify biotransformation reactions.

     

The occurrence of brassicasterol and epibrassicasterol in the chromophycota

• 1.1. Sterols were identified from eight isolates of five species in the Chromophycota that were cultured axenically and harvested in the stationary phase.
• 2.2. Analyses were performed on four strains from the Prymnesiophyceae, two strains from the Cryptophyceae and one from the Bacillariophyceae. Most strains examined contained only one major sterol, 24-methyl-22-dehydrocholesterol.
• 3.3. Analysis by capillary GC, HPLC, and in one instance NMR, showed that the two strains provisionally identified as Isochrysis contained brassicasterol (24β-methyl-22-dehydrocholesterol); whereas, all other species examined contained primarily epibrassicasterol (24α-methyl-22-dehydrocholesterol).
• 4.4. Stigmasterol (24α-ethyl-22-dehydrocholesterol) accompanied epibrassicasterol in Pleurochrysis carterae.
• 5.5. Analyses of C-24 alkyl isomers in these algae may provide useful information concerning their taxonomic placement.
• 6.6. The occurrence of both isomers of 24-methyl-22-dehydrocholesterol in oysters is explained by the occurrence of both isomers among algae which are probably dietary sources for oysters.

     

The energetics of shedding: Energy content of snake skin

• 1.1. The weight and energy content of sloughed skins of 92 individual snakes of 22 different species in three families were measured.
• 2.2. Weight and total energy content of shed skins were highly correlated with body weight.
• 3.3. The heat of combustion (kJ/g) of sloughed skins varied significantly among families and was higher in species having unkeeled scales than in those with keeled scales.
• 4.4. The presence of keels significantly affected weight of skins, even when skin weight is adjusted for covariance with body weight.
• 5.5. Neither body weight nor ambient temperature significantly affected the heat of combustion of sloughed skins.
• 6.6. The energy content of shed skin, expressed as a proportion of daily metabolism, decreased with ambient temperature, but the effect is minimized in large snakes.
• 7.7. Small snakes expended relatively less energy in sloughed skins than large snakes when the expenditure is expressed in terms of total daily metabolized energy.

     

Indole-, imidazole- and phenyl-alkylamines in the skin of one hundred and forty american amphibian species other than bufonids

• 1.1. Extracts prepared from dried or fresh skins of 140 American amphibian species, other than bufonids, were subjected to chemical and biological screening in order to determine the presence and concentrations of aromatic biogenic amines.
• 2.2. The most frequent and abundantly occurring amine category was that of indolealkylamines, represented by their prototype 5-hydroxytryptamine and its N-methylated derivatives. Conjugated and cyclized indolealkylamines, typical for the toad skin, were apparently lacking.
• 3.3. Phenylalkylamines were represented by two quaternary ammonium bases: leptodactyline and, very rarely, candicine. Leptodactyline was particularly abundant in leptodactylid frogs of the genus Leptodactylus.
• 4.4. Histamine occurred in trace amounts in different species, in large amounts only in some Leptodactylus species of the “pachypus” section. On the other hand, N-methylated histamines and cyclized histamines (spinaceamines) were confined to the skin of Leptodactylus pentadactylus labyrinthicus.
• 5.5. The possible taxonomical and evolutionary significance of amphibian skin amines is pointed out.

     

Oxygen consumption and production by tropical ascidians symbiotic with Prochloron

• 1.1. Oxygen consumption and production rates were measured in two species of colonial ascidians that contained the algal symbiont, Prochloron.
• 2.2. Despite differences in size and habitats, the colonies showed similar rates of oxygen consumption and production.
• 3.3. Oxygen production by the colonies was light dependent.
• 4.4. Based on the data presented, the symbiosis is similar to other algal-invertebrate symbioses in producing more oxygen than is consumed when illuminated.

     

Purification and characterization of a novel imidazole dipeptide synthase from the muscle of the Japanese eel Anguilla japonica

We have purified a novel enzyme from eel white muscle which catalyzes the syntheses of imidazole dipeptides, such as carnosine (β-alanyl-l-histidine), anserine (β-alanyl-π-methyl-l-histidine), and balenine (ophidine; β-alanyl-τ-methyl-l-histidine), directly from their precursors. The enzyme was purified 1130-fold from eel muscle by a series of column chromatographies. Although eel muscle contains a large amount of carnosine and only trace amounts of anserine and balenine, the anserine synthesizing activity was by far the highest. From gel permeation chromatography, the molecular mass of the enzyme was calculated to be 275 kDa. SDS-PAGE of the purified enzyme represented a band around 43 kDa, suggesting that the native enzyme is a hexamer or heptamer. The optimal pH and temperature were around 9.5 and 60 °C, respectively. K_m values for β-alanine and π-methyl-l-histidine were 44 and 89 mM, respectively. The enzyme was greatly activated by Zn²⁺ and inhibited by EDTA. The N-terminal amino acid sequence of 25 residues of the purified enzyme showed 52% amino acid identity to 38–62 residues of zebrafish haptoglobin precursor. The purified enzyme also exhibited hydrolytic activity against these imidazole dipeptides.     

The taurine content of avian erythrocytes and its role in osmoregulation

• 1.1. The taurine content of erythrocytes from 15 avian species contained levels of taurine in the range of 20–70 mmol/kg of hemoglobin, about 100-fold that of mammalian red blood cells.
• 2.2. This high taurine content did not appear to be related to the nucleation of these cells as nucleated amphibian erythrocytes and human reticulocytes contained low levels.
• 3.3. The erythrocytes lacked cysteine sulfinic acid decarboxylase, a key enzyme in the synthesis of taurine from cysteine, indicating a probable lack of synthetic capabilities.
• 4.4. The cells were able to accumulate labeled taurine against a concentration gradient. This uptake was inhibited by β-alanine and was Na⁺-dependent.
• 5.5. When incubated in hypotonic medium, the cell volume of pigeon erythrocytes rapidly increased and was followed by a much slower return to normal size. The cell volume reduction was accompanied by a slow efflux of taurine into the medium.
• 6.6. These data suggest that taurine plays a role in cell volume maintenance and osmotic regulation in avian erythrocytes.

     

Isolation of crustacean egg yolk lipoproteins by differential density gradient ultracentrifugation

• 1.1. Egg yolk lipoproteins from four species of Crustacea were isolated by differential density gradient ultracentrifugation.
• 2.2. Egg yolk proteins from freshwater prawn, striped stone crab and mitten crab consissted of high-density lipoprotein (HDL) and lipid-free protein, while low-density lipoprotein (LDL) was present in the egg yolk protein of sand crayfish as well as HDL and lipid-free protein.
• 3.3. HDL was a major component in the egg yolk proteins from four species of Crustacea. HDL was identical to egg yolk lipovitellin.
• 4.4. Both HDL and LDL possessed phospholipid as a major lipid.
• 5.5. HDL, but not LDL, contained carotenoids. The color of HDL from mitten crab showed a reddish purple and was distinct from other Crustacea whose color was orange. The reddish purple color was characterized by an absorption flexion at 600–650 nm.

     

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.

     

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Seasonal variation in the metabolic rates and Q10-values of the fingernail clam,Sphaerium striatinum lamarck

• 1.1. Metabolic rates were highest during periods of maximum reproduction.
• 2.2. The exponent of the metabolic rate-weight equation varied seasonally, rates of metabolism of small animals exhibited greater annual fluctuations than those of large animals.
• 3.3. Absolute and weight-specific Q₁₀s (determined at 5–10°C above field temperatures) for smaller clams were greatest in the winter; absolute values of Q₁₀ were highest for larger individuals in the summer.
• 4.4. Small clams had Q₁₀ < 1.0 in the summer; Q₁₀-values for larger clams were near 1.0 at this time.
• 5.5. 38.9% of the total energy assimilated by the population annually was allocated to metabolism, which is near the low end of the range of values reported for freshwater molluscs, suggesting that this species can partition a large amount of energy to growth and reproduction.

     

Sex-specific androgen binding in spotted hyaena (Crocuta crocuta) plasma

• 1.1. A charcoal adsorption assay demonstrated a large variance in androgen binding ability in female spotted hyaenas.
• 2.2. A positive correlation between plasma androgen binding ability and ovarian steroid concentrations was demonstrated in adult females.
• 3.3. The strong plasma binding affinity for testosterone and dihydrotestosterone (DHT) (nM) together with the lack of cortisol and weaker oestradiol-17β binding suggests that a specific androgen binding substance, possibly a protein, is present in adult females of this species.
• 4.4. The lack of high affinity binding in male spotted hyaenas is unusual and deserves further investigation.
• 5.5. Some androgen binding in all, including males and immature animals suggests that albumin may bind some plasma androgens in this species.