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Showing papers in "Comparative Biochemistry and Physiology B in 1973"


Journal ArticleDOI
TL;DR: For example, the phospholipid-bound fatty acids of all species except the rabbit were quantitatively the most important fatty acid found in all species, except for the rabbit.
Abstract: 1. 1. The phospholipid-bound fatty acids of ram, bull, boar, rabbit and human spermatozoa contained high levels of polyunsaturated fatty acids. Values ranged from 70 per cent by weight of the total fatty acid fraction in the boar to approximately 40 per cent in both human and rabbit. 2. 2. Docosahexaenoic acid (22:6) was quantitatively the most important fatty acid found in all species except the rabbit. 3. 3. The major saturated fatty acid found in mammalian spermatozoa was palmitic acid. 4. 4. The predominant fatty aldehyde was palmitaldehyde (16:0) and values ranged from 91·2 per cent in ram to 51·1 per cent in human spermatozoa.

171 citations


Journal ArticleDOI
TL;DR: Major characteristics which appear to be taxonomically related include the relatively high levels of palmitoleic acid in dipterous insects and high levels in some families of hemipterous Insects.
Abstract: 1. 1. The fatty acid compositions of the seven insect orders, Lepidoptera, Hemiptera, Orthoptera, Diptera, Hymenoptera and Dictyoptera differ quantitatively in a number of respects with regard to the relative percentages of the commonly occurring fatty acids, myristic, myristoleic, palmitic, palmitoleic, stearic, oleic, linoleic and linolenic acids. 2. 2. Major characteristics which appear to be taxonomically related include the relatively high levels of palmitoleic acid in dipterous insects and high levels of myristic acid in some families of hemipterous insects. The exceptions are discussed. 3. 3. The apparent significance of the fatty acid composition, in general, is discussed.

139 citations


Journal ArticleDOI
TL;DR: Photoperiod schedules were used to control the onset of parrsmolt transformation in steelhead trout and ATPase activity was decreased and migration reduced when animals were subjected to temeperatures of about 13°C or greater, or when the length of increasing photoperiods approximated that of the summer solstice.
Abstract: 1. 1. Photoperiod schedules were used to control the onset of parrsmolt transformation in steelhead trout ( Salmo gairdneri ). 2. 2. Gill Na + , K + -stimulated ATPase activity was elevated in smolts exhibiting migratory behavior. 3. 3. ATPase activity was decreased and migration reduced when animals were subjected to temeperatures of about 13°C or greater, or when the length of increasing photoperiods approximated that of the summer solstice (22 June).

133 citations


Journal ArticleDOI
TL;DR: The purified insect lytic enzymes are small basic proteins with properties, such as stability to heat, optima for pH and ionic strength, similar to those of egg white lyso enzyme, but with specific activities about six times that of lysozyme.
Abstract: 1. 1. Bacteriolytic activity develops in haemolymph of immature stages of Bomyx mori and Galleria mellonella after injection with microorganisms but not after saline injection. 2. 2. The purified insect lytic enzymes are small basic proteins with properties, such as stability to heat, optima for pH and ionic strength, similar to those of egg white lysozyme, but with specific activities about six times that of lysozyme. 3. 3. The Galleria enzyme releases from bacterial cell walls reducing sugar end groups which were identified as acetylmuramic acid. The properties of the insect proteins permit their classification as mucopeptide N-aacetylmuramyl- hydrolase (E.C. 3.2.1.17).

111 citations


Journal ArticleDOI
TL;DR: A comparison was made of the differing ability of hearts, isolated from homeothermic and poikilothermic animals, to maintain beating at low temperature, and differences were observed between the activation energy (or temperature coefficient Q 10 ) for each type of heart.
Abstract: 1. 1. A comparison was made of the differing ability of hearts, isolated from homeothermic and poikilothermic animals, to maintain beating at low temperature. Over the temperature range (0–37°C) differences were observed between the activation energy (or temperature coefficient Q 10 ) for each type of heart. 2. 2. The activation energy for beat rate of the homeothermic heart dramatically increased below approximately 21·0°C. The heart beat of a poikilothermic animal maintained a constant activation energy over the full temperature range 0–37°C. 3. 3. The change in heart beat at 21°C for the homeotherm can be correlated with both temperature-induced phase changes in the lipid components of membranes, and the change in the activation energy of membrane-associated ATPases. None of these changes were observed in the membranes of the heart of the poikilotherm.

99 citations


Journal ArticleDOI
TL;DR: The amino- and organic acids together incorporated about 85 per cent of the total radioactivity of mussel homogenate both after 24 and 48 hr of anaerobiosis, and the incorporation of radioactivity by the amino acids was mainly confined to alanine and glutamic acid.
Abstract: 1. 1. The distribution of radioactivity over different classes of chemical compounds from glucose- ul - 14 C injected into the sea mussel Mytilus edulis was examined after 24 and 48 hr of anaerobiosis. 2. 2. The amino- and organic acids together incorporated about 85 per cent of the total radioactivity of mussel homogenate both after 24 and 48 hr of anaerobiosis. 3. 3. The incorporation of radioactivity by the amino acids was mainly confined to alanine and glutamic acid. The level of alanine remained much the same after 24 or 48 hr of incubation but the level of glumatic acid increased. 4. 4. The incorporation of radioactivity by the organic acids was mainly confined to succinate.

98 citations


Journal ArticleDOI
R.G. Ackman1, S.N. Hooper1
TL;DR: A critical examination of the fatty acids from total lipids and certain lipid fractions of the periwinkle, moon snal and sand shrimp has been carried out by open-tubular gas-liquid chromatography, detecting two sets of novel fatty acids that were not obvious components in the lipids of the sand shrimp.
Abstract: 1. 1. A critical examination of the fatty acids from total lipids and certain lipid fractions of the periwinkle (Littorina littorea), moon snal (Lunatia trisepriata) and sand shrimp (Crangon septemspinosus) has been carried out by open-tubular gas-liquid chromatography. 2. 2. In the mollusc lipids two sets of novel fatty acids were detected in analyses by open-tubular column gas-lipid chromatography. These had previously been respectively included in packed column analyses with the eicosenoic and docosenoic acids. 3. 3. These acids are believed to have non-methylene-interrupted structures in which two of the three eicosadienoic acids each have one ethylenic bond in the Δ 5 position and the others in positions mimicking the corresponding normal monoethylenic fatty acids, while in two docosadienoic acids the first ethylenic bond is thought to be in the Δ 7 position. 4. 4. These novel fatty acids were not obvious components in the lipids of the sand shrimp which, however, shared with the molluscs emphasis on chain extension of 9-hexadecenoic acid to 13-eicosenoic acid.

93 citations


Journal ArticleDOI
TL;DR: Eggshells of the Araucano fowl contain protoporphyrin, biliverdin IXa and its zinc chelate and traces of coproporphyrins I, which have significance in eggshell pigmentation and calcification.
Abstract: 1. 1. Eggshells of the Araucano fowl contain protoporphyrin, biliverdin IXa and its zinc chelate and traces of coproporphyrin I. 2. 2. These results and their significance in eggshell pigmentation and calcification are discussed.

92 citations


Journal ArticleDOI
TL;DR: The enzymes involved in ascorbic acid synthesis are apparently lacking in the liver and kidney of both the blue and channel catfish, and the symptoms are described.
Abstract: 1. 1. Ascorbic acid deficiency has been demonstrated in the channel catfish and the symptoms are described. 2. 2. The enzymes involved in ascorbic acid synthesis are apparently lacking in the liver and kidney of both the blue and channel catfish.

68 citations


Journal ArticleDOI
TL;DR: The time course of metabolite production has been used to evaluate the significance of acetate, succinate and carbon dioxide formation in vivo and indicates that succinate production is induced by in vitro incubation.
Abstract: 1. 1. Monomorphic Trypanosoma brucei and T. rhodesiense metabolize glucose via the glycolytic pathway, producing pyruvate as the major metabolic end-product with a small amount of glycerol and no carbon dioxide, acetate or succinate. 2. 2. Under in vitro conditions, pleomorphic strains of T. rhodesiense produce significant quantities of succinate, acetate and carbon dioxide. 3. 3. The time course of metabolite production has been used to evaluate the significance of acetate, succinate and carbon dioxide formation in vivo and indicates that succinate production is induced by in vitro incubation. 4. 4. Oxidative decarboxylases for pyruvate and α-oxoglutarate are confined to the short stumpy forms of pleomorphic infections. However, the tricarboxylic acid cycle has minimal activity in these organisms due to limiting levels of citrate synthase (E.C. 4.1.3.7) and succinate dehydrogenase (E.C. 1.3.99.1). 5. 5. l -Glycerol-3-phosphate oxidase is the principal terminal oxidase of both long slender and short stumpy forms of T. rhodesiense .

55 citations


Journal ArticleDOI
TL;DR: This enzyme was more stable in neutral or alkaline medium than in acid medium and was inhibited by ethylenediaminetetracetic acid but not by diisopropylfluorophosphate or monoiodoacetamide, which revealed that this enzyme was medially specific.
Abstract: 1. 1. Some properties of an isolated hatching enzyme of the medaka, Oryzias latipes , were studied. 2. 2. Under the assay conditions, the enzyme was inhibited by high concentrations of Na + , K + , Ca 2+ and Mg 2+ , while it was slightly activated by them at low concentrations. The optimum pH of this enzyme was around 7·9. 3. 3. This enzyme was more stable in neutral or alkaline medium than in acid medium and was inhibited by ethylenediaminetetracetic acid but not by diisopropylfluorophosphate or monoiodoacetamide. 4. 4. A substrate specificity test using some synthetic substrates revealed that this enzyme was medially specific.

Journal ArticleDOI
TL;DR: Agarose gel electrophoresis was performed on the sera of thirty-six mammals, reptiles, amphibians, fish and birds, and the quantitative distribution of the lipoprotein classes in each animal was determined.
Abstract: 1 1 Agarose gel electrophoresis was performed on the sera of thirty-six mammals, reptiles, amphibians, fish and birds, and the quantitative distribution of the lipoprotein classes in each animal was determined 2 2 Pig, opossum and garter snake sera seem to contain large amounts of low density lipoprotein, the lipoprotein class which is of primary interest in atherosclerosis research These animals also have serum cholesterol values similar to humans 3 3 Agarose gel electrophoresis proved an excellent method for determining lipoprotein distributions, but the electrophoretic mobilities of the lipoproteins appear to be unsuitable for lipoprotein classification

Journal ArticleDOI
TL;DR: In this paper, the authors compared the digestives enzymes in isolated cod pyloric caeca and of the isolated mesentery of the caeca, compared with those found in extracts of total caeca not separated into caeca and mesenteries fractions.
Abstract: 1. 1. Digestive enzymes in extracts of isolated cod pyloric caeca and of the isolated mesentery of the caeca were compared with those found in extracts of total pyloric caeca not separated into caeca and mesentery fractions. 2. 2. Trypsin, chymotrypsin, carboxypeptidase A and carboxypeptidase B were restricted to the mesentery which also contained most of the ribonuclease and amylase. Leucine aminopeptidase and acid and alkaline phosphatase in contrast had a more even distribution between various tissues. 3. 3. Trypsinogen and chymotrypsinogen were present in extracts of mesentery but were not detected in extracts of total caeca.

Journal ArticleDOI
TL;DR: Adelie penguins breeding at Cape Crozier, Antarctica, arrive in the colony from the sea in October at the beginning of the austral summer and both sexes fast while on the breeding colony for 3–6 weeks before returning to the sea to feed.
Abstract: 1. 1. Adelie penguins (Pygoscelis adeliae) breeding at Cape Crozier, Antarctica, arrive in the colony from the sea in October at the beginning of the austral summer. Both sexes fast while on the breeding colony for 3–6 weeks before returning to the sea to feed. 2. 2. Six individuals collected during the first fast period showed decreased blubber thickness and a linearly corresponding decrease in ether extractable fat with time after arrival in the breeding area. Birds contained about 45 per cent of dry weight as fat upon arrival, and in a typical incubation, males decreased to about 20 per cent after day 27. 3. 3. The decrease in fat represents approximately 56 g of fat used per day by fasting male Adelies for the 27-day period. On the basis of this value, it has been estimated that 490 kcal/bird per day approximates energy demands for these fasting birds during the early part of the breeding season. 4. 4. Fatty acid compositions of total ether extractable lipids, subcutaneous fat and abdominal depot fat did not differ significantly except in a few of the long-chain acids. Depot fat fatty acids of normal breeding birds did not change significantly from arrival on the colony to day 27. 5. 5. Proportions of fatty acids in Adelie penguin depot fat correspond with the proportions of fatty acids in their normal diet of krill (Euphausia superba).

Journal ArticleDOI
TL;DR: Electrophoretic analyses reveal no detectable qualitative or quantitative alterations in the isozyme patterns due to the effects of temperature acclimation at 5, 15 and 25°C.
Abstract: 1. 1. The lactate dehydrogenase and malate dehydrogenase isozyme patterns from goldfish ( Carassius auratus L.) tissues were examined by starch gel electrophoresis and immunoprecipitation. 2. 2. Electrophoretic analyses reveal no detectable qualitative or quantitative alterations in the isozyme patterns due to the effects of temperature acclimation at 5, 15 and 25°C. 3. 3. The only variations of LDH * isozyme patterns observed were those attributable to genetic polymorphism and to different ratios of red and white skeletal muscle fibres.

Journal ArticleDOI
Ichiro Iuchi1
TL;DR: The larval hemoglobin was characterized with higher oxygen affinity and less Bohr effect compared with the adult hemoglobin which loses oxygen affinity sharply at pH's below 7·6, suggesting that both hemoglobins are tetrameric and contain protoporphyrin IX.
Abstract: 1. 1. Comparative studies on chemical and physiological characteristics of hemoglobins isolated from newly hatched larvae and adult fish of rainbow trout were carried out. 2. 2. No significant differences in absorption spectrum and in molecular size were observed between them, suggesting that both hemoglobins are tetrameric and contain protoporphyrin IX. 3. 3. The larval hemoglobin was more labile than the adult one upon alkali denaturation. Electrophoretic studies revealed that both hemoglobins and their subunits were highly polymorphic, without having subunit components common to both hemoglobins. 4. 4. Although overall amino acid compositions of both hemoglobins were similar in general, the difference in the amino acid residues responsible for net charges at pH 8·6 was observed. 5. 5. The larval hemoglobin was characterized with higher oxygen affinity and less Bohr effect compared with the adult hemoglobin which loses oxygen affinity sharply at pH's below 7·6.

Journal ArticleDOI
TL;DR: A comparison of the mass action ratios of the glycolytic enzymes with their equilibrium constants has shown that in Ascaris muscle, phosphoglucomutase, glucosephosphate isomerase, aldolase, trioseph phosphate isomersase, phosphoglyceromutase and phosphopyruvate hydratase are all at or near equilibrium, whilst phosphofructokinase and pyruvates kinase are displaced from equilibrium.
Abstract: 1. 1. The activities of the glycolytic and associated enzymes have been investigated in the muscle tissue of Ascaris lumbricoides and the steady-state content of the phosphorylated glycolytic intermediates measured in freeze clamped tissue. 2. 2. A comparison of the mass action ratios of the glycolytic enzymes with their equilibrium constants has shown that in Ascaris muscle, phosphoglucomutase, glucosephosphate isomerase, aldolase, triosephosphate isomerase, phosphoglyceromutase and phosphopyruvate hydratase are all at or near equilibrium, whilst phosphofructokinase and pyruvate kinase are displaced from equilibrium. 3. 3. The results are discussed in relation to the energy metabolism of the parasite.

Journal ArticleDOI
TL;DR: A comparison of the contents of high-sULphur, low-sulphur and high-tyrosine proteins in various keratins taken in conjunction with parallel X-ray diffraction studies suggests that the high-tiesine proteins occur in the matrix rather than in the microfibrils.
Abstract: 1. 1. In addition to high-sulphur and low-sulphur proteins a third class of proteins rich in tyrosine and glycine occurs in mammalian hard keratins and is particularly abundant in porcupine quill and echidna quill. 2. 2. A comparison of the contents of high-sulphur, low-sulphur and high-tyrosine proteins in various keratins taken in conjunction with parallel X-ray diffraction studies suggests that the high-tyrosine proteins occur in the matrix rather than in the microfibrils.

Journal ArticleDOI
TL;DR: Temperature-dependent kinetic properties may give the LDH isozymes of G. mirabilis a major role in determining the metabolic fate of pyruvate, which can be channneled preferentially towards the Krebs cycle at low temperatures and efficiently converted to lactate at higher temperatures.
Abstract: 1. 1. The lactate dehydrogenase (LDH) isozymes present in white skeletal muscle of Gillichthys mirabilis exhibit substrate (pyruvate) inhibition only at temperature below 25°C. The extent of pyruvate inhibition is inversely proportional to temperature. 2. 2. The apparent K m of pyruvate is essentially temperature-independent between 10 and 25°C. At higher temperature in the organism's physiolohgical range the apparent K m of pyruvate increases as temperature is raised. 3. 3. These temperature-dependent kinetic properties may give the LDH isozymes of G. mirabilis a major role in determining the metabolic fate of pyruvate. 4. 4. At higher temperatures, when oxygen availability is reduced and the orgnism's activity level is apt to be relatively high, pyruvate may be efficiently converted to lactate, i.e. the fish can rely on anaerobic glycolysis. 5. 5. At low temperatures, when the opposite conditions of oxygen avalability and organismal activity pertain, pyruvate can be channneled preferentially towards the Krebs cycle.

Journal ArticleDOI
TL;DR: Erythrocytic NDP kinase activities were high and electrophoretically heterogeneous in all species examined and patterns of nucleotide extracts of whole blood and erythrocytes in seal, eel, hagfish, dogfish, nurse shark and stingray were similar when determined by high-pressure liquid chromatography.
Abstract: 1. 1. The activities of AMP kinase, GMP kinase, NDP kinase, PNPase and HGPRTase were determined in the erythrocytes of seal, eel, hagfish and dogfish. 2. 2. Erythrocytic NDP kinase activities were high and electrophoretically heterogeneous in all species examined. 3. 3. Patterns of nucleotide extracts of whole blood and erythrocytes in seal, sand dab, skate, hagfish, dogfish, nurse shark and stingray were similar when determined by high-pressure liquid chromatography. Patterns of the whole blood of eel and lemon shark, however, were strikingly different in containing large amounts of GDP and GTP.

Journal ArticleDOI
TL;DR: Interspecific hybrids never occurred, neither within the population nor in the laboratory interbreeding experiments with or without hormonal pretreatment, and this failure may be due to the genetic differences between both species.
Abstract: 1. 1. In the two closely related rodent species, Apodemus sylvaticus and Apodemus flavicollis , thirty-three different protein markers and the chromosome banding pattern as produced by special staining techniques were compared. Breeding and interbreeding experiments were also performed. 2. 2. Both species differ in the electrophoretic position of twelve out of thirty-three protein markers and in the existence of telomeric heterochromatin on five chromosome pairs. 3. 3. Interspecific hybrids never occurred, neither within the population nor in the laboratory interbreeding experiments with or without hormonal pretreatment. This failure may be due to the genetic differences between both species.

Journal ArticleDOI
TL;DR: The patterns and mobilities supported perviously assumed monophyletic origins for the genera Percina and Etheostoma and suggested that the nominal species may actually consist of two or more taxonomically recognizable forms.
Abstract: 1 1 Lactate dehydrogenase isozyme patterns were obtained for sixty-seven species of darters, tetrazolium oxidase electrophoretic mobilities for sixty-eight species and malate dehydrogenase isozyme patterns for fifty-seven species 2 2 The patterns and mobilities supported perviously assumed monophyletic origins for the genera Percina and Etheostoma 3 3 Several accepted relationships among darters were supported, and new relationship were suggested 4 4 Geographic variation was limited; the most significant variation was the dichotomous nature of the LDH pattern of P copelandi suggesting that the nominal species may actually consist of two or more taxonomically recognizable forms

Journal ArticleDOI
TL;DR: In this paper, the Pyruvate kinase (PK) from the trematode Schistosoma mansoni closely resembles PK from rabbit muscle in its response to various purine and pyrimidine nucleoside diphosphates and divalent cations, in its sensitivity to activation by FDP and relative insensitivity to inhibition by ATP and in its somewhat higher affinity for PEP.
Abstract: 1. 1. Pyruvate kinase (PK) from the trematode Schistosoma mansoni closely resembles PK from rabbit muscle in its response to various purine and pyrimidine nucleoside diphosphates and divalent cations, in its insensitivity to activation by FDP and relative insensitivity to inhibition by ATP and in its somewhat higher affinity for PEP. 2. 2. PK's from the filarial nematodes Litomosoides carinii and Dirofilaria immitis closely resemble PK from rabbit liver in the pattern of their substrate and cofactor specificities, by being strongly activated by FDP and inhibited by ATP, and by showing a relatively lower affinity for PEP. 3. 3. The properties of PK from S. mansoni miracidia were indistinguishable from those of PK from the adult forms, and this was also the case for the PK's from D. immitis microfilariae and adults. 4. 4. The molecular weights of PK's from S. mansoni , D. immitis and rabbit muscle were all around 270,000±10 per cent.

Journal ArticleDOI
TL;DR: N,N-dimethylaniline was oxidized readily by liver homogenates from nurse shark and lemon shark but only slightly by homogenate from spiny dogfish and little skate, and a similar pattern was found for the oxidation of trimethylamine.
Abstract: 1. 1. Trimethylamine (TMA) oxidase activity was characterized in nurse shark (Ginglymostoma cirratum) liver homogenates. Enzyme activity was absolutely dependent on NADPH and was localized mainly in the microsomes. 2. 2. Inhibitors of cytochrome oxidase (azide) and cytochrome P-450 (CO and SKF-525A) had little or no effect on TMA oxidase activity. 3. 3. The tertiary amines, N,N-dimethylaniline and chlorpromazine, inhibited TMA oxidation. 4. 4. N,N-dimethylaniline was oxidized readily by liver homogenates from nurse shark and lemon shark but only slightly by homogenates from spiny dogfish and little skate. A similar pattern was found for the oxidation of trimethylamine.

Journal ArticleDOI
TL;DR: The view that steroid hormones are present in the gonadic tissue of A. depilans and could be produced from cholesterol and acetate, while hepatic tissue contains only the enzymatic systems, which are able to synthesize steroids is supported.
Abstract: 1. 1. The steroid content of the gonads and hepatopancreas of the marine mollusc Aplysia depilans has been analysed. 2. 2. The following steroids have been identified in the gonad extract: pregnenolone,∗ progesterone, 17α-hydroxyprogesterone, testosterone, oestradiol and oestrone; pregnenolone and 17α-hydroxypregnenolone have been identified in hepatic tissue. 3. 3. Incubations of these tissues with acetate-1-14C and cholesterol-4-14C yielded the following metabolites: cholesterol, 20α-hydroxycholesterol, pregnenolone, 17α-hydroxypregnenolone, dehydroepiandrosterone, progesterone, 17α-hydroxyprogesterone, androstenedione, testosterone, cortisol, cortisone and deoxycorticosterone. 4. 4. These findings support the view that steroid hormones are present in the gonadic tissue of A. depilans and could be produced from cholesterol and acetate, while hepatic tissue contains only the enzymatic systems, which are able to synthesize steroids.

Journal ArticleDOI
TL;DR: An estimate of the genetic polymorphism and average hetorozygosity in three species of rockfish, Sebastes alutus, S. caurinus, and S. elongatus' was made using differences in electrophoretic mobility of proteins on starch gel to yield estimates of 8,4 and 8 per cent of all polymorphic for the average species population.
Abstract: 1. 1. An estimate of the genetic polymorphism and average hetorozygosity in three species of rockfish, Sebastes alutus, S. caurinus, and S. elongatus' was made using differences in electrophoretic mobility of proteins on starch gel. 2. 2. In S. alutus two of twenty-five loci; in S. caurinus, one of twenty-five loci; and in S. elongatus, two of twenty-four loci were polymorphic. 3. 3. This yields estimates of 8,4 and 8 per cent of all polymorphic for the average species population and values of 3·8, 1·8 and 3·3 per cent for the proportion of the genome heterozygous per individual in the average population.

Journal ArticleDOI
M. De Rosa1, L. Minale1, Guido Sodano1
TL;DR: A fuller analysis of the minor sterols from Verongia aerophoba showed the presence of all known compounds except for a C 30 di-unsaturated component which was present in very small amounts.
Abstract: 1. 1. Twenty-five species of Porifera were examined for sterols with the main purpose of looking for aplysterol (I) and 24,28-didehydroaplysterol (II), which are recently discovered sterols from Verongia aerophoba with an unprecedented side-chain pattern. 2. 2. Aplysterol (I) and didehydroaplysterol (II) appear to be confined solely to the family Verongidae. 3. 3. All species were found to have very complex mixtures and the Δ 5 -sterols are the most widely distributed. In Spongidae we found Δ 5,7 -sterols almost exclusively. They are also the principal components of two Axinella species and Dysidea avara . Δ 5,7 -sterols must therefore be accounted as new to the Porifera. 4. 4. Axinella polypoides and A. verrucosa contain stanols of what seems to be a completely new type, and a full characterization is now in progress. 5. 5. A fuller analysis of the minor sterols from Verongia aerophoba showed the presence of all known compounds except for a C 30 di-unsaturated component which was present in very small amounts.

Journal ArticleDOI
TL;DR: The nematode stimulates catabolism and/or suppresses anabolism of proteins by the host fat body, to provide a dietary source of amino acids within the haemolymph to stimulate vitellogenesis, growth requirements of the developing parasite and possible involvement of the host endocrine system.
Abstract: 1. 1. Using polyacrylamide disc electrophoresis, eight soluble protein fractions were demonstrable in measurable amounts within the yolk of Schistocerca gregaria . 2. 2. Female locusts were infected 3 days after their imaginal moult with equal doses of Mermis nigrescens ova and electropherograms of their haemolymph and fat body proteins were compared with a group of uninfected (control) females. Effects of the parasite upon host protein turnover were appraised in relation to the host's gonotropic cycle. 3. 3. The nematode caused only a sporadic depletion of vitellogenic and non-vitellogenic protein fractions before and during the vitellogenesis period of controls (initial 2 weeks' infection). The ability of the terminal oocytes to sequester vitellogenic proteins from the host haemolymph was impaired by the parasite, so vitellogenesis commenced but was not completed in infected hosts. 4. 4. At 3 weeks' infection, haemolymph protein fractions were significantly diminished (cf. controls) by parassitism but were not so depleted 3 days later. Concurrently, terminal and penultimate oocytes of infected locusts were resorbed. 5. 5. Effects of the nematode on the insect's fat body soluble proteins preceded analogous changes in haemolymph protein fractions. Two weeks after infection, ten of seventeen soluble protein fractions were significantly depleted in the fat bodies of infected locusts (cf. controls). Three weeks after infection, only six fat body protein bands were significantly depleted in infected insects (cf. controls) whilst four such protein fractions were present at significantly higher levels than in the controls. 6. 6. The nematode stimulates catabolism and/or suppresses anabolism of proteins by the host fat body, to provide a dietary source of amino acids within the haemolymph. This effect of M. nigrescens parasitism upon protein turnover in the locust is discussed in relation to host vitellogenesis, growth requirements of the developing parasite and possible involvement of the host endocrine system.

Journal ArticleDOI
TL;DR: A rapid method is described for isolating mitochondria from the fat body tissue of the cockroach Blaberus discoidalis, and the symbiotic micro-organisms found in fat body mycetocytes were rare.
Abstract: 1. 1. A rapid method is described for isolating mitochondria from the fat body tissue of the cockroach Blaberus discoidalis. 2. 2. Oxidative activity was comparable to that of conventional procedures with a recovery of 50 per cent of the initial total respiratory activity. With succinate, ADP:O = 1.6 and respiratory control ratios were between 3 and 4. 3. 3. Electron microscopy showed isolated fat body mitochondria to be about 1.0 μm in dia. with a condensed ultrastructure. Only slight amounts of membraneous contamination were found in pellets, and the symbiotic micro-organisms found in fat body mycetocytes were rare.

Journal ArticleDOI
TL;DR: The liver and kidney arginases were activated by Mn2+ ions and exhibited Km values similar to those previously reported for ureotelic species.
Abstract: 1. 1. The activities of carbamyl phosphate synthetase, ornithine transcarbamylase, arginine synthetase system and arginase were measured in liver and kidney homogenates of cultured and native channel catfish. 2. 2. Significant levels of carbamyl phosphate synthetase, ornithine transcarbamylase and arginase were detected in liver tissue, whereas only ornithine transcarbamylase and arginase were detected in kidney tissue. 3. 3. The liver and kidney arginases were activated by Mn2+ ions and exhibited Km values similar to those previously reported for ureotelic species.