1.1. Two kinds of neurons were identified in the body-wall longitudinal muscle layer of the earthworm, Amynthas hawayanus, by the simultaneous potential recording and Lucifer Yellow-CH injection method with a single microelectrode.
2.2. Both kinds of neurons have their somata, neuntes and longitudinal processes imbedded in the longitudinal muscle layer. Those with two circular processes extending into the third segmental nerve trunk are tentatively named “intra-nerve-trunk” neurons and those with four circular processes extending into four setae shafts are tentatively named “intramural” neurons.
3.3. Both kinds of neurons responded to electrical and mechanical stimuli applied in an afferent direction to them.
4.4. The “intra-nerve-trunk” neuron decreased its response amplitudes to these stimuli after the third nerve trunk was sectioned in correlation to the response amplitude decrease recorded from the nerve trunk after it was sectioned.
5.5. The response amplitude decrease due to denervation implies a nonlinear structure of the earthworm reflex circuits.
6.6. The “intramural” neurons are believed to be primary sensory neurons connected to the mechanoreceptors in the setae.
1.1. Subcellular distribution of (NA+, K+-ATPase and ouabain-insensitive ATPase (Mg2+-ATPase) are compared in branchial tissues of the euryhaline crab, Eriocheir sinensis, acclimated to fresh water.
2.2. Both the anterior and posterior gills contain cAMP-dependent protein kinase and endogenous protein substrate for phosphorylation.
3.3. Phosphorylation occurs in both “particulate” and “soluble” subcellular fractions but its stimulation by cAMP is restricted to the “soluble” fraction.
4.4. serotonin (5-HT) and dopamine receptors are present only in the “light particulate” fraction isolated from the posterior gills.
1.(a) Serotonin and dopamine have no effect on the phosphorylation observed in a subcellular fraction alone.
2.(b) Activation of the phosphorylation by serotonin and dopamine is found when the soluble fraction (source of cAMP-dependent protein kinase) is added to the fraction P3 from the posterior gills.
3.(c) No activation occurs with the fractions P3 as well as P1 or P2 (not shown) from anterior gills of fresh water crab.
4.(d) Cyproheptadine, a serotonin receptor antagonist, inhibits the 5-HT dependent increase in phosphorylation.
5.(e) The dopamine receptor antagonist, chlorpromazine, inhibits dopamine-stimulated phosphorylation.
6.5. Ouabain mimics the effect of cyproheptadine on the serotonin-stimulated phosphorylation found in the posterior gills.
1.1. Two morphotypes of Myliobatis from the demersal fishery off the Rio Grande (Brazil) were studied.
2.2. Thirty-two alleles were detected and resolved by 27 loci.
3.3. Nei's measure of genetic identity was 0.8306 and Thorpe's similarity was 0.6990. Mean heterozygosities observed were 0.1327 for the “DE” morphotype and 0.0409 for the “DL” morphotype.
4.4. Seven loci were fixed differently in the two taxa studied. This indicates the existence of a barrier to gene-flow between them, showing that both morphotypes belong to different species.
5.5. Jaccard's measure of similarity was calculated and a phenogram with the two morphotypes and M. freminvillii was constructed using isoelectric focusing of total soluble proteins. This showed a higher similarity between the two morphotypes of Myliobatis than M. freminvillii.
1.1. Specific Dynamic Action (SDA) effects of diet were investigated in the supralittoral isopod, Ligia pallasii, using defined chemical diets.
2.2. “Apparent SDA”, or the total rise in metabolic rate following a meal, was resolved in animals eating a nutritionally complete chemical diet into three components: 8% mechanical costs of moving food through the gut, 40% “excitement costs” due to investigator disturbance and presence of food, and 52% SDA.
3.3. Excitement costs in animals exposed to food but which chose not to eat showed non-significant variation between diets containing different levels of chemical nutrients, but were significantly less on a diet containing only cellulose and agar.
4.4. SDA increased with increasing concentration of amino acids in the diet.
5.5. Substitution of whole-protein casein for free amino acids in the diet had no significant SDA effect, while substitution of free amino acids in the ratio found in casein more than doubled the SDA effect.
6.6. Deletion of alanine from the diet caused no significant effect on SDA, while deletion of phenylalanine caused a highly significant elevation in SDA.
1.1. The oxygen consumption of red and green Carcinus in normoxic and hypoxic sea water was determined, using an oxygen electrode in a sealed respirometer.
2.2. The red crabs had significantly higher “excited” oxygen uptake rates and a lower ability to compensate for hypoxia than the green crabs.
3.3. Red Carcinus display an emersion response to declining oxygen at lower oxygen tensions than the green crabs.
4.4. Mortality of red crabs exposed to prolonged anoxia was much greater.
5.5. The relationship of these findings to the zonation of the two colour forms on the shore is discussed.
1.1. Two “en passant” electrodes were implanted around the cerebrobuecal connective (CBC) of Aplysia and used to record the activity, in the unrestrained animal, under three behavioural conditions; (a) absence of feeding behaviour, (b) appetitive feeding behaviour and (c) consummatory feeding behaviour.
2.2. The two simultaneous recordings were subjected to cross-correlation analysis, to subdivide spikes on the basis of their direction and speed of propagation.
3.3. There was virtually no CBC activity in the absence of food and feeding behaviour.
4.4. During appetitive feeding the metacerebral giant cell (MCC) was active and traffic was heaviest in the cerebral-to-buccal direction.
5.5. During consummatory feeding, traffic was also sustained in the buccal-to-cerebral direction; there was a reduction in the activity of the MCC, and a peak in the activity travelling to the cerebral ganglia, in the region of higher conduction velocity, was especially pronounced.
6.6. Further analysis showed this peak to have its largest amplitude during the actual ingestion of food and to be the result of the firing of several different units.
7.7. CBC traffic in both directions was also activated in one case of “spontaneous” biting.
1.1. The electric organ discharge (EOD) frequency modulations evoked by brief water vibration were analysed in the pulse-type fish Gymnotus carapo.
2.2. The response consisted of a transient increase of the EOD frequency at short latency (30 msec). Response profiles were characteristic of the specimen and relatively independent on stimulus intensity.
3.3. Conversely, they were dependent on stimulation sequence, showing a rapid decrement along successive stimuli and high temporal discrimination.
4.4. The brief latencies indicate a relatively simple neural circuit.
5.5. The response may be an electrolocation enhancement strategy for the detection of moving objects based on “sampling” the periphery at a higher frequency.
1.1. The effects of sublethal concentrations of organic and inorganic pollutants on intracellular energy-rich phosphates in blue mussels, Mytilus edulis, were investigated by in vivo31P-NMR.
2.2. Formaldehyde (30 and 10mg/l), phenol, pyridine, mercury and cadmium gave marked reductions in phosphoarginine and, in some cases, the ATP amounts. The reduction in high-energy phosphate was accompanied by an increase in inorganic phosphate in all groups.
3.3. A “phosphorus index”, the product of the ratios between phosphoarginine and inorganic phosphate, and ATP and inorganic phosphate, is suggested, which might serve as an early warning (“alarm”) parameter in environmental monitoring.
4.4. Diversity in the responses to different pollutants make phosphorus compounds in M. edulis also an interesting element in a finger print parameter system designed to distinguish between pollutants in the marine environment.
1.1. The phenoloxidase activity, protein and carbohydrate levels were studied for 24 hr in the hemolymph of the migratory grasshopper, Melanoplus sanguinipes after artificial wounding of the insect cuticle or the injection of Beauveria bassiana conidia.
2.2. Injection or wounding induced a primary response and phenoloxidase activity was found to increase within 10–60 min. The values for phenoloxidase activity in viable B. bassiana-injected insects exhibited a secondary response, i.e., an increase 24 hr after injection.
3.3. In wounded insects and those injected with inactivated conidia, the phenoloxidase activity receded after the initial increase and remained at low levels.
4.4. Protein concentrations in the hemolymph increased immediately after infection and wounding and returned to basal levels during the course of the experiment.
5.5. Injection of viable B. bassiana resulted in a gradual increase in the protein concentrations between 12 and 24 hr.
6.6. There was no apparent change in the carbohydrate levels in either B. bassiana-infected or wounded insects.
7.7. These results are discussed in relation to their possible role(s) and interrelationships in the immune response to infection or wounding. Furthermore, we suggest that a “factor” is released after mechanical injury of the integument.
1.1. Inductively coupled plasma atomic emission spectroscopy (ICP-AES) was used to measure iron concentration in several body tissues throughout the life cycle of the lamprey, Petromyzon marinus L.
2.2. Iron concentration in the liver rises sharply during metamorphosis, decreases in parasitic adults, and falls to the lowest value in upstream migrants.
3.3. In the intestine, the concentration of this metal is highest in the larval stage, but values decline steadily through transformation to their lowest levels in parasitic adults.
4.4. Dorsal skin has, on average, three times the iron content of ventral skin and it is only in upstream migrants that the levels of both regions increase significantly over those of other stages.
5.5. Differences in iron concentration in tissues of larval and adult lampreys reflect changes which take place at metamorphosis.
1.1. Homing pigeons, receiving regular flight-training for participation in racing competitions, were flown from their usual release site, 48 km away from “home”.
2.2. On their return “home” within 60–80 min, blood samples for the measurement of melatonin were taken within 1–3 min of arrival.
3.3. Post-flight circulating levels of melatonin were found to be about 82% higher than those of the resting control pigeons without any change in plasma osmolality.
4.4. This daytime increase in circulating levels of melatonin suggests that melatonin, by virtue of its known hypothermic effect of facilitating peripheral heat dissipation, could prevent excessive flight-induced hyperthermia.
5.5. It is also suggested that the flight-induced increase in plasma levels of melatonin is consistent with the known analgesic and metabolic effects of the hormone.
1.1. The features of neoplasia which predict for drug responsiveness are rapid growth and/or inefficient repair of damage, especially to DNA.
2.2. PDT has the advantage of yielding responses regardless of the growth fraction of a tumor, and repair appears to play only a minor role.
3.3. While an entirely different spectrum of tumors can be targeted with PDT, the perhaps unavoidable accompaniment is that a new set of rules for efficacy will need to be established.
4.4. The selectivity of PDT is based on the need for irradiation which can be directed, along with the short tissue half-life of the cytotoxic product, singlet oxygen. Sensitizers which target specific cellular organelles could promote PDT efficacy, if in vitro data (Woodbum et at., 1992b Photochem. Photobiol. 55, 697–704) can be translated into clinical practice.
5.5. It remains to be established whether total drug distribution to neoplastic tissues or concentration in specific sub-cellular sites is the more important factor.
6.6. Questions relating to the role of biodistribution as a factor in efficacy of PDT sensitizers of photosensitizers remain to be explored. Just as the political cartographers are grappling with changes in territorial boundaries of known lands, we continue to clarify the rules relating to PDT boundaries. In this regard, it is clearly important for determinants of pharmacokinetics and biodistribution to be evaluated and understood.
7.7. Once clinical reports on the “second generation” agents are published, we may get a better picture, although it is not unusual for clinical reports to raise more questions than they answer.
8.8. It seems safe to conclude that there is nothing “magic” about HPD, and that additional efficacious photosensitizers for PDT can be produced.
9.9. If we find that a wide variety of different structures are useful in the clinic, a likely conclusion is that there are multiple mechanisms of tumor localization. Since the nature of neoplasia is so diverse, this possibility should not be surprising.
10.10. In view of the finding, cited above, that liposomes show about the same degree of tumor selectivity as does Photofrin, it may be feasible to target any efficient photosensitizer for neoplastic tissues by development of an appropriate delivery system.
1.1. Changes in turgor, in cell volume, in membrane potential, in intracellular ionic activities and, more recently, in spontaneous electrical activity have been reported to be causally linked to the expression of specific genes.
2.2. As a result, it has become clear that changes in membrane properties and/or in the intracellular “ionic environment” can play an important role in generating cell type specific physiological responses which indirectly—or maybe directly—affect gene expression.
3.3. Possible targets of the ionic “environment” are: the selective transport across biological membranes; the activity of certain (regulatory) enzymes; the conformation of some (regulatory) proteins; of chromatin; of the cytoskeleton; of the nuclear matrix; the association of the cytoskeleton with plasmamembrane proteins or RNA; the association chromatin-nuclear matrix; protein-DNA and protein-protein interactions etc. All these sites may be instrumental to “fine or coarse” tuning of gene expression.
4.4. The exact mechanisms by which changes in intracellular ionic environment are transduced, directly or indirectly, into alterations of the activity of trans-acting factors have not yet been fully uncovered. Changes in the degree of phosphorylation of regulatory proteins and/or of trans -acting factors may provoke fine tuning effects on cell type specific gene expression activity.
5.5. The intranuclear ionic environment is difficult to measure in an exact way. It can be influenced in a number of ways. The location of a gene, as determined by the position of the nucleus in the cytoplasm and by the association of chromatin to the nuclear matrix may be especially important in cells which can generate some type of intracellular gradient or in excitable cells.
6.6. In some somatic cell types—germinal vesicles may behave differently—the intranuclear inorganic ionic “environment” has been reported to be distinct from the cytoplasmic one. This challenges the widespread assumption that the nuclear envelope is always freely permeable to small molecules and inorganic ions.
7.7. It can be expected that the fast progress in the cloning of “electrically” controlled genes, in the identification of trans-acting factors, in their mode of interaction with genes and in the precise localization of genes within the nucleus may soon lead to substantial progress in this domain.
1.1. Communication is so essential to the living state at all its different levels of organization, from the cell organelle to the population, that in my opinion life could be defined as follows: Death ensues when the ability to communicate at the highest level of organization of the biological system under consideration is irreversibly lost.
2.2. The most primitive means of communication in the first cell which appeared on earth may have been ionic/electrical in nature. In the course of Evolution, a variety of additional means of communication have been generated.
3.3. Communication by whatever means requires gradients together with energy acquired from the environment.
4.4. “Life” might not have originated earlier than the moment that the first ionic gradient was actively established over the limiting membrane of the first cell. It may not be excluded that the ability to drive an ionic flux through itself, this implying polarity, was a second essential prerequisite for the living state to arise.
5.5. The formation of the primitive, polarized and order bringing cytoskeleton may have been as important as that of nucleic acids for the living state to arise and to acquire its full asset of means of communication.
6.6. “Life” may have originated many times in the primordial conditions before an ionically/electrically compartmentalized and polarized aggregate finally achieved orderly division and multiplication. Only then did the long term life traits for perpetuating a population and for generating diversity come into play.
7.7. If the proposed definition is correct, it follows that the term “life” implies flexibility because the ability to communicate depends on the steepness and the nature of the gradients: “life” presents itself in many forms and gradations.
8.8. The definition given under 1. or, more practically, “life: the ability to communicate” may bring more unity in all the different meanings which the different disciplines studying “life” intuitively attribute to their study object.
1.1. The plasma membrane of slime-forming, encapsulated Streptococcus cremoris from “viili” was isolated in hypotonie conditions in the presence of lysozyme (EC 3.2.1.17) using density gradient centrifugation as the last purification step.
2.2. The membrane yield was 15.8% of wet weight cells and the preparation contained 64.4% protein. 19.1% carbohydrate, 5.8% aminosugars, 5.1% RNA and 0.07% DNA.
3.3. Buffered 1% (w/v) Triton X-100 solubilized 33.6% of membrane proteins. The number of polypeptides detected by SDS-polyacrylamide gel electrophoresis was 59 when the membrane was isolated without a protease inhibitor and 44 in the presence of a protease inhibitor.
4.4. The molecular weights of the polypeptides varied from 13,500 to 100,000.
5.5. Ultrathin-layer electrofocusing analysis revealed the range of protein pi values to be between 3.50 and 5.85 concerning 77.3% of proteins and between pI 5.85 and 8.15 concerning 18.2% of proteins.
6.6. The isoelectric point of the only basic protein component was 9.3.
1.1. Mixed-function oxidase (MFO) system components (cytochrome P-450, “418-peak”, cytochrome b5 and NADPH-cytochrome c (P-450) reductase) and inducible antioxidant enzymes (catalase, Superoxide dismutase (SOD), glutathione peroxidase (GPX) and DT-diaphorase) has been determined in digestive glands of mussels (Mylilus galloprovincialis) collected from three Mediterranean coastal locations, exhibiting an organic pollution gradient.
2.2. Cytochrome P-450, the “418-peak”, catalase and SOD showed a good correlation with whole body tissue PAHs and, to a lower extent, with PCBs.
3.3. Microsomal NADPH-dependent DT-diaphorase, but not the NADH-dependent microsomal enzyme or the cytosolic DT-diaphorases, was indicated to increase with pollution exposure.
4.4. The application of such measurements to environmental monitoring is discussed. Given the magnitude of differences observed, and the state of knowledge on enzyme function and mechanisms of toxicity, a multiparameter approach is considered to offer current and future potential for detecting the impact of organic pollution on bivalve molluscs.
1.1. Two species of hydrothermal vent bivalve molluscs have high glycine content periostraca but that of Calyptogena magnifica is rich in methionine and tyrosine while that of Bathymodiolus thermophilus has the highest glycine content recorded for any natural polypeptide.
2.2. The amino acid compositions are compared with other periostracal proteins, as found in species adapted to “normal” environments, in terms of hydrophobic character, polar content and conformational potential.
3.3. The significance of the composition and possible physico-chemical characteristics of the hydrothermal species periostraca for adaptation to and protection against the unusual environmental conditions are discussed.
1.1. The histopathology of zebra mussel populations (Dreissena polymorpha) which were transplanted and exposed in baskets in the Dutch sector of the River Maas (5 locations) were compared with indigenous wild mussels at the same locations and at a clean reference site in the Ijsselmeer.
2.2. All groups were sectioned histologically and examined to quantify cytological damage and pathology of a wide range of tissues, as well as to examine parasitology and to assess their reproductive state.
3.3. Results show a significant reduction in general cytological quality and an increase in observed pathological conditions in the wild populations at the 3 downstream stations.
4.4. The transplanted (active biomonitoring) groups of mussels clearly showed a similar trend in condition after only 42 days exposure at these sites.
5.5. The influence of an industrial spillage of Cd in the Maas during the exposures is examined against this background of locally varying “health”.
1.1. Comparative aspects of iodine conservation in mammals were studied on the basis of published data on kidney and thyroid weights and function.
2.2. Very small mammals possessed an efficient reabsorption of iodide to compensate for the high glomerular nitration rate (GFR).
3.3. Humans and mammals of a similar and larger size had “lost” the ability to reabsorb iodide efficiently.
4.4. Very large mammals are protected against renal loss of iodide due to the relatively low GFR.
5.5. Thyroid weights in relation to body weight were highest in humans suggesting that humans and other mammals of a similar size are especially susceptible to iodine deficiency.
