Seasonal variations in biochemical constituents of the clam,Paphia laterisulca

1. The total protein, fat and glycogen contents were estimated from the edible clam, P. laterisulca. Seasonal variations in these constituents along with the water content were studied.
2. The gonad index in P. laterisulca was found to increase during the ripe condition and in winter (December–January) and decrease on spawning.
3. A relatively high water content was obtained during monsoon (June to September). This might be due to the loss of salts and gain of water in low salinities.
4. Protein content varied with the reproductive cycle of the clam. The level reached its peak in the mature stage and declined on spawning. Immature clams showed less protein content than gravid ones.
5. Lipid content started to increase as the gametogenesis commenced, reached its peak in fully mature condition (August) and sharply declined due to the shedding of gametes during spawning.
6. Glycogen content was high during the period of active gameto-genesis (May–June). A sharp decrease took place when the clams were fully ripe (July). The glycogen might have been utilized in the formation of active ripe gametes.
7. After starvation for twelve days, total protein and fat contents remained constant, while glycogen content decreased by 66.82%. The water content increased by 4.67%.
8. Seasonal variation in the organic constituents are discussed in relation to the reproductive cycle of the clam.

     

Seasonal variation in the energy metabolism in an estuarine crab,Chasmagnathus granulata (Dana, 1851)

• 1.1. The effects of seasonal variation on the carbohydrate and lipid metabolism of the Chasmagnathus granulata were investigated.
• 2.2. Glycemia is high in winter and summer and low in spring and fall.
• 3.3. The glycogen content in the hepatopancreas and muscle is higher in fall and winter, and decreases during spring and summer.
• 4.4. The muscle lipids are higher in summer, and decrease during fall and winter whereas hepatopancreas lipids are higher except in the fall.
• 5.5. The crabs show change in the metabolic pattern of lipids and carbohydrates during the seasons of the year.

     

Rhythmisches Mycelwachstum bei Podospora anserina

The correlation between membrane structure and morphogenesis in fungi was examined by studying the effect of surface-active and membrane-altering substances upon the colonial shape of Podospora anserina. The following results were obtained:

1. The alcohols 1-propanol, 1-butanol and 1-octanol inhibited hyphal elongation and thus caused zonations in the wild strain. In the clock-mutant zonata, however, the zonations disappeared at high concentrations of the alcohols.
2. The detergents sodium-dodecylsulfate, sodium-desoxycholate, triton X-100 and brij-35 also induced zonations, i.e. rhythmic growth. Growing on complete media, the sensibility of the strains used was markedly reduced.
3. The antibiotics nonactin, nigericin and monensin, too, inhibited growth and caused zonations, which, however, were light dependent. In contrast, valinomycin inhibited the elongation of the hyphae only.

The results are discussed as consequences of alterations in structure and features of the membranes.     

Lipid and carbohydrate metabolism of the intertidal crab Chasmagnathus granulata dana, 1851 (Crustacea: Decapoda) during emersion

• 1.1. Lipid, glucose and glycogen concentrations were measured in different tissues of the crab Chasmagnathus granulata during emersion.
• 2.2. After 6 hr of emersion no reduction in the total amount of carbohydrates was found to occur, suggesting that a general metabolic arrest was taking place.
• 3.3. A transitory increase in haemolymphatic glucose and lipid levels was observed. Possible causes are therefore discussed in relation to changes in the flux of substrates for energy production.
• 4.4. The mobilization of carbohydrates and lipids to the gills, observed only during summer, may be concerned with energy supplying for ionic regulation.

     

Effects of membrane-perturbing drugs and noradrenalin on cAMP accumulation and red cell water content in carp (Cyprinus carpio) red cells

• 1.1. Carp red cells were treated with drugs that affect the cell membranes. The water content of the cells and the accumulation of cAMP in the cells were measured in normoxia and in hypoxia using non-stimulated and adrenergically stimulated cells.
• 2.2. WGA, DIDS + CCCP and A23187 increased the water content of nonstimulated normoxic cells.
• 3.3. In hypoxia ouabain and DIDS + CCCP increased the water content but cytochalasin B, NPM, DIDS, CCCP and A23187 + CA²⁺ abolished the hypoxia-induced swelling.
• 4.4. Any membrane perturbation induced some cAMP formation, Sophora and Anquilla lectins being most potent.
• 5.5. Also in adrenergically stimulated cells, membrane perturbation generally increased cAMP formation.
• 6.6. However, cAMP accumulation diminished in cells treated with cytochalasin B, CCCP and DIDS + CCCP.
• 7.7. The adrenergic swelling of carp red cells was reduced in normoxia by DIDS. NPM and CCCP increased the adrenergic swelling in normoxia to hypoxic level.
• 8.8. In hypoxia WGA and Anquilla lectin decreased the swelling.

     

Experimental problems using electronic particle counters

The following scheme lists the problems which have been and will continue to be encountered in grazing experiments on natural particle assemblages. In some cases there are solutions, but many of the problems listed below remain intractable. To solve them will require innovative approaches, most probably combining the use of particle counters with other techniques to approach the problem to be solved from several angles at once. Variance between samples due to

- statistical causes (especially caused by large particles) and

- differences between experimental bottles and between experimentals and controls at start of experiment. Shifts in particle distribution during experiment due to

- increase in small particles

- growth of bacteria and other organisms due to excretion of grazers and

- breakage during handling by grazers into fragments. Processes, independent of grazing, leading to changes in particle size distribution due to

- primary production

- grazing by additional components and

- bacterial growth on detrital particles and the formation of detrital flocs.

     

A study on the rate of water transport of the clam katelysia opima in relation to environmental conditions

1. The neutral red technique was employed to study the rate of filtration in Katelysia opima.
2. The weight specific water filtration was found to be greater for younger clams compared to the older ones.
3. The rate of water filtration increased with decreasing salinity.
4. Water filtration was found to increase as temperature increased, reaching a maximum at 35°C. but then sharply decreasing at 39°C.
5. Light had no significant effect on the rate of filtration.
6. Suspended matter was found to affect the rate of water filtration.
7. The rate of filtration was low at high pH and high in low pH.
8. The rate of water filtration was found to be faster during high tide than during low tide.
9. The presence of the parasitic crab, Pennotheris sp., in the mantle cavity of clams had a marked effect on the particle filtration.
10. Accidental cut of the siphon tips had no effect on the rate of filtration.

     

Effect of feeding on the respiration rate of the rotifer Brachionus plicatilis

The effect of feeding on the respiration rate of Brachionus plicatilis was studied. Oxygen consumption was determined under two feeding regimes, duplicate feeding and constant feeding. Oxygen consumption rate increased during feeding. The oxygen consumption profile is discussed in relation to the following processes:

1. filtration, mastication, and locomotion during feeding
2. specific dynamic action (SDA)
3. egg formation and routine metabolism.

     

Anaerobic respiration in latex ofHevea brasiliensis substrate and limiting factors

The site of anaerobic respiration in the latex is the serum. The main respiratory substrate is fructose. The CO₂ formation in serum is increased by additional fructose on the average about 2.5–3 times. Glucose does not influence CO₂ evolution by serum but slightly increases O₂ consumption. With respect to sugars, latex serum contains essentially only sucrose and a low amount of raffinose. During the incubation of serum sucrose is hydrolysed, the fructose component is immediately utilized in respiration and glucose accumulates. The rate of CO₂ formation in latex as influenced by fructose is negatively related to the rubber content of the latex. Latex with a high rubber content reacts only slightly or not at all on additional fructose. The main limiting factors of latex respiration and sugar utilization are the following:

1. The deficiency of substrate, due to low activity of β-fructofuranosidase.
2. The rate of glucose phosphorylation (D'Auzac, Jacob 1967).
3. Presumably the low activity of phosphoglucoisomerase.
4. The rubber content of the latex.
5. The concentration of CO₂ in latex; this factor may be important in vivo, in the laticiferous system.

     

Biogenesis of mitochondria 20 the effects of altered membrane lipid composition on mitochondrial oxidative phosphorylation inSaccharomyces cerevisiae

1. The lipid composition of mitochondria isolated from a fatty acid desaturase mutant ofSaccharomyces cerevisiae may be extensively manipulated by growing the organism on defined supplements of unsaturated fatty acid (UFA).
2. The fatty acid composition of the mitochondrial lipids closely follows that of the whole cells from which the mitochondria are isolated. UFA-depleted mitochondria contain normal levels of sterols, neutral lipids and total phospholipids, but have much lower levels of phosphatidyl inositides.
3. UFA-depleted mitochondria possess a full complement of cytochromes, oxidase both NAD-linked and flavoprotein-linked substrates at normal rates, and have levels of succinate and malate dehydrogenases similar to those of UFA-supplemented mitochondria. However, UFA-depletion has a marked effect on the ability of cytochromec to reactivate the NADH oxidase activity of cytochromec-depleted mitochondria.
4. The efficiency of oxidative phosphorylation decreases progressively with the UFA content of the mitochondria, and oxidative phosphorylation is completely lost in mitochondria containing approximately 20% UFA.
5. The incorporation of UFA into the lipids of UFA-depleted mitochondriain vivo results in a recoupling of oxidative phosphorylation. Recoupling is insensitive to both chloramphenicol and cycloheximide, indicating that all the proteins necessary for oxidative phosphorylation are present in UFA-depleted mitochondria, and that the less of oxidative phosphorylation is a purely lipid lesion.
6. ATPase activity is apparently unaffected by UFA-depletion, but³²P_i-ATP exchange activity is lost in mitochondria which have been extensively depleted in UFA.
7. Valinomycin stimulates the respiration of UFA-supplemented mitochondria in media containing potassium, but has no effect on the respiration of UFA-depleted mitochondria, suggesting that active transport of potassium is lost as a result of UFA-depletion.

     

Seasonal variation in the biochemical composition of Mytilus viridis at Ratnagiri on the West Coast of India

1. The seasonal variation in the water, protein, fat and glycogen contents of the mussel, Mytilus viridis has been studied for the year March, 1974 to March, 1975.
2. The water level increased during the monsoon season and decreased in summer.
3. The level of protein, fat and glycogen showed correlation with the reproductive cycle of the mussel.
4. The protein level was high when the mussels were mature and dropped during the breeding period.
5. During sex change from male to female in May the protein level remained high whereas during sex change from female to male in October and November it was low.
6. The fat level was high in mature mussels and declined on spawning.
7. The glycogen level was at its peak in immature mussels and low in mature.

     

Effet des androgènes sur l’activité sportive

Androgenic hormones seem to be of beneficial effects on sports performance:

- they increase motivation, will, aggressiveness, resistance to the stress and to the fatigue, leading to an increase of the training quantity,

- they increase bone mineralization and probably mechanical resistance,

- they stimulate the bone marrow and so, with the erythropoietin, the erythropoiesis,

- they increase the tendancy to hyperglycemia, but with a decrease of the tolerance to the glucose,

- they stimulate the fatty acids mobilization from the adipose tissue, for their utilization in the muscle during the exercise,

- they participate, for the trained sportmen, to a better gestion of the muscle glycogen storage: their utilization during exercise is decreased,

- they increase the lean body mass, with an increase of the protein synthesis and a decrease of the protein catabolism, leading also to an increase of the muscle force under training. There is no beneficial effect upon the tendons,

- they have an immunomodulation action.

     

Adenine nucleotide pool variations in intact Nitrobacter winogradskyi cells

1. The ATP pool in Nitrobacter winogradskyi cells was determined by means of the luciferin-luciferase enzyme system and the ADP and AMP pools were measured after enzymatic conversion into ATP.
2. In the fist 10 min after addition of nitrite to endogenously respiring cells, which had stood for 5–16 days after completion of the nitrite oxidation, the ATP pool dropped about 60%.
3. During the log phase the ATP pool was approx. 20–40 pmoles/5 μg cell-N. During growth it increased exponentially by 3–4 times the amount until the nitrite had been used up. Subsequently the ATP pool decreased at first rapidly and then more slowly without sinking to 0 in the first 2 months after nitrification.
4. Nitrite oxidizing cells had an energy charge of 0.37 during the log-phase. After approx. 90% of the substrate had been used up the energy charge had reached 0.57.
5. If the CO₂ assimilation was inhibited in growing cultures by increased oxygen partial pressure, nitrite oxidation continued but the ATP pool increased.
6. The ATP pool and the activity of the endogenous respiration decreased by more than 50% during the first hours after the substrate had been used up.

     

Recherches histophysiologiques sur le développement post-embrynnaire et le cycle annuel deFormica rufa (Hyménoptère)

Histochemical methods applied to the fat body ofFormica rufa queens show during the postembryonnic development, the following results:

1. Synthesis of lipids, glycogen and protein, successively occur in the cytoplasm of larval adipose cells. At the time of cocoon spinning, the energetic reserves (glycogen and mainly lipids) regress. During the nymphosis, the proteins are used for the histogenesis of the imaginal organs; yet, part of the proteins synthetised by the prenymph is transformed by the nymph into lipids, or constitutes the protein reserves of the swarming imago.
2. The nitrogenous products, which are copious for the larva, undergo transformations during the nymphosis, but reappear in microscristallin form at the hatching.

     

Metabolism of the anaerobic formation of succinic acid bySaccharomyces cerevisiae

1. Succinic acid is formed in amounts of 0.2–1.7 g/l by fermenting yeasts of the genusSaccharomyces during the exponential growth phase. No differences were observed between the various species, respiratory deficient mutants and wild type strains.
2. At low glucose concentrations the formation of succinic acid depended on the amount of sugar fermented. However, the nitrogen source was found to be of greater importance than the carbon source.
3. Of all nitrogen sources, glutamate yielded the highest amounts of succinic acid. Glutamate led to an oxidative and aspartate to a reductive formation of succinic acid.
4. A reductive formation of succinic acid by the citric acid cycle enzymes was observed with malate. This was partially inhibited by malonate. No evidence was obtained that the glyoxylate cycle is involved in succinic acid formation by yeasts.
5. Anaerobically grown cells ofSaccharomyces cerevisiae contained α-ketoglutarate dehydrogenase. Its activity was found in the 175000 x g sediment after fractionated centrifugation. The specific activity increased 6-fold after growth on glutamate as compared with cells grown on ammonium sulfate.
6. The specific activities of malate dehydrogenase, fumarase, succinate dehydrogenase, succinylcoenzymeA synthetase, α-ketoglutarate dehydrogenase and glutamate dehydrogenase (nicotinamide adenine dinucleotide dependent) were determined in yeast cells grown on glutamate or ammonium sulfate. Similar results were obtained with a wild type strain and a respiratory deficient mutant. The latter did not contain succinate dehydrogenase.
7. In fermenting yeasts succinic acid is mainly formed from glutamate by oxidation.

     

Inhibition of carotenoid synthesis in Myxococcus fulvus (Myxobacterales)

1. The inhibitory effects of CPTA, nicotine, DPA, and San 6706 on carotenogenesis in Myxococcus fulvus were investigated.
2. The effects of CPTA, D-nicotine, and L-nicotine were very similar. The action of the drugs wasadditive. The cyclization was inhibited at low doses, the introduction of the hydroxyl group at C-1′ at higher doses. Lycopene accumulated at high drug concentration. The mode of action of the inhibitors is discussed.
3. In a carotenoid mutant of M. fulvus a stimulation of the “7,8-dehydrogenase” by CPTA was observed.
4. The specific carotenoid content of bacteria was increased by DPA due to an enhanced formation of phytoene. At low doses of DPA small amounts of an intermediate carotenoid glucoside ester, a 7,8-dihydro derivative, were detected.
5. DPA was taken up by the plasma membrane. Quantitative removal of DPA by washing was not possible.
6. San 6706 specifically and reversibly blocked the desaturation of phytoene.

     

Effects of Environmental Perturbations on Short-Term Phytoplankton Production off Lawson's Bay,A Tropical Coastal Embayment

1. The phytoplankton cycle off Lawson's Bay, Waltair follows a bimodal pattern with a major peak during March–May; a minor peak during October–November months and with a low production during the summer months i.e., June–August.
2. During the summer months of 1957, 1958, 1960 and 1962 dumping of dredged spoil from the entrance channel of the harbour into the sea resulted in a natural enrichment of waters.
3. Following this enrichment, there was a qualitative and quantitative increase in the phytoplankters thus leading to the development of a bloom.
4. Only Thalassiosira subtilis and Chaetoceros curvisetus commonly bloomed during the four years.
5. The increase in gross production which varied from 3–13 fold and the high photosynthesis-respiration ratios 5.1 to 10.5 indicated that the bloom populations were in a healthy state.
6. The decrease of the populations to the initial levels suggests that some unknown factor, other than those investigated must have been operating.
7. Consequences of eutrophication of different origins on stimulation of phytoplankton production are briefly discussed.

     

Intracellular proteolytic activity in developing myxospores of Myxococcus xanthus

1. Cell-free extracts from vegetative cells and developing myxospores of Myxococcus xanthus were found to contain similar amounts of proteolytic activity, approximately 80% of which was due to one or more neutral metal proteases.
2. Sixty per cent of the proteolytic activity was particulate.
3. The specific activity of the proteases was high throughout all stages of myxospore formation and displayed small increases in activity at two stages of development: (1) during cell shortening and (2) immediately following the conversion to spheres. The first peak in activity was apparent in assays conducted at pH 8 or 10 whereas the second peak was obvious only at pH 6.
4. A mutant which develops into myxospores only after a lag of approximately 7–8 h possessed levels of proteases similar to the wild type and displayed a peak in proteolytic activity after a delay of 7–8 h.
5. Low levels of serine protease activity were occasionally detected in both vegetative cells and myxospores; no sulfhydryl proteases were detectable in either cell type.
6. Extracellular proteases accumulated in the medium throughout myxospore development but differed from the intracellular proteases in pH optima and sensitivity to inhibitors.

     

Temporal discharge patterns of tectal and medullary neurons chronically recorded during snapping toward prey in toads Bufo bufo spinosus

In freely moving toads, the temporal discharge patterns of tectal and medullary neurons were observed during prey-catching.

1. Tectal T5.2 and T8.1 neurons displayed a premotor warming up firing that in the former was addressed specifically to prey orienting or snapping and in the latter generally to almost any kind of body movement.
2. The temporal discharge patterns of T5.2 neurons during snapping were different from those during orienting toward prey. Snapping started in the peak phase of warming up; firing was immediately terminated during the snap; thereafter some rebound activity was observed. Orienting started after the premotor warming up in the declining phase whilst the neuron kept on firing during orienting and then settled when the orienting movement was completed.
3. In toads which were not motivated to catch prey — comparabl to immobilized ones — the discharge frequency of T5.2 neurons toward a prey stimulus revealed no such warming up.
4. Because it is known that prey-selective T5.2 neurons are controlled by pretectal inhibitory influences, the following experiment was conducted: during recording a T5.2 neuron a pretectal lesion was applied ipsilaterally to the recording site. After a few seconds, the neuron showed a strong premotor wanning up in response to any kind of moving object, followed by prey-catching.
5. In the medulla oblongata, different H-type neurons of the hypoglossal nucleus displayed specific discharge patterns which resembled the tongue protractor and retractor muscle activities; a third type resembled the activity of the genio/sterno-hyoid muscle, which are suggested to stabilize the hyoid bone during snapping.
6. There were medullary M8-type neurons with properties similar to T8.1.
7. Snapping could be triggered by electrical stimulation of the optic tectum in the representation of the frontal visual field, but not by stimulation in the hypoglossal nucleus or the adjacent medial reticular formation.
8. A concept of a neuronal circuit for the coordination of tongue muscle contractions in response to prey is proposed.

     

The influence of EDTA on the composition of alginate synthesized by Azotobacter vinelandii

1. During an investigation of the physiology of Azotobacter vinelandii with particular reference to polysaccharide formation, a suitable medium which was precipitate-free was developed by adding EDTA at a concentration of 50 mg/l to a basal medium containing one of eight different carbohydrates as sole carbon source.
2. Acetylated alginate was always produced by the organism when cultured under defined conditions, regardless of the carbohydrate source incorporated in the basal medium.
3. When EDTA was added to the medium, the bacteria produced acetylated polyuronides with a preponderance of mannuronic acid residues.
4. A comparison of the infrared spectra of the alginate produced by Azotobacter vinelandii and the affect of EDTA upon the mannuronic acid/guluronic acid ratios of the alginate are reported.