Impact of polychlorinated biphenyls on the activity of intestinal proteinases and carbohydrases in juvenile roach Rutilus rutilus (L.)

The chronic effects that polychlorinated biphenyls (PCBs) have on the activities of proteinases and carbohydrates in intestinal mucosa and chyme in juvenile roach Rutilus rutilus (L.) have been studied for the first time. Upon consuming food with PCB 50.8 ng/g wet weight for 218 days, the exposition of fingerlings in aquariums with dirt bottoms (contents PCB 425.6 ng/g dry weight) reduces the proteolytic activity of mucosa to a greater degree than amylolytic activity; the activity of sucrase changes in different directions. In 2-year-old fish receiving PCB only with food (50.8 ng/g wet weight bottom), proteolytic and amylolytic activities of the mucosa are reduced 18 and 35% in comparison with the control (52 days); the sucrose activity is reduced 13% (52 days) and 22% (169 days). In most cases the relation of amylolytic activity to proteolytic activity in fish of the experimental groups is less than in the control. The enzyme activities in chyme change in different directions, depending on the terms and conditions of the experiment.     

The effects of temperature and adrenergic agonists on cardiac myocytes of perch (Perca fluviatilis) in cell culture conditions

1. 1. Isolated cardiac myocytes of perch, Perca fluviatilis, were kept in culture conditions for 1–2 months at 12 or 22°C. In the culture most myocytes flattened, lost their spindle-shaped morphology, protruded pseudopod-like branches and many of them started visible contractions in 1–2 weeks and continued beating for several months. Myocytes did not divide in the sparse cell population used. Typical intracellular structures could be seen in electron micrographs still after 1–2 months, but the sarcoplasmic organization became gradually more irregular in the culture.

2. 2. Beat rates showed linear temperature relationship on the Arrhenius plot. Myocytes cultivated at 22°C showed higher frequencies and slightly less dependence on temperature than myocytes cultivated at 12°C (apparent activation energies (E_a) 86 and 107 kJ/mol, respectively).

3. 3. Temperature dependence of frequencies was related to the presence of added serum or adrenergic agonists: β-adrenergic agonists increased the frequencies and rendered the cells less dependent on temperature; apparent activation energy was 43 kJ/mol for isoprenaline or adrenaline and 108 kJ/mol for noradrenaline and control group.

4. 4. Heat tolerance was greater in myocytes cultivated at 22°C than in myocytes cultivated at 12°C, and the change in tolerance appeared in 12 h after the alteration of culture temperature and the increased tolerance was persistent after that.

5. 5. It is suggested, that the processes of quick heat-hardening and of slower but persistent heat resistance acclimation developed in these cells in culture conditions but not the capacity acclimation, which seems to be dependent on adrenergic regulation of beat rate.

Perch (Perca fluviatilis L.) parasites reflect ecosystem conditions: a comparison of a natural lake and two acidic reservoirs in Finland

Parasite communities of perch were studied in a natural lake (Vetämäjärvi) and two reservoirs (the Kyrkösjärvi and Liikapuro reservoirs) located in Western Finland. All water bodies studied are small, shallow and humic. However, the reservoirs are more acidic than the lake (pH 5.9 and 5.3 vs. 6.4). Altogether, 18 parasite species were found, but the component communities were reduced in the harsh conditions of the reservoirs (12 and six species) as compared with the lake (17 species). In addition, the mean number of metazoan parasite specimens per fish was markedly lower in the reservoirs (64.3 and 14.3 specimens) than in the lake (116.1 specimens). Our prediction on the depauperation of parasite communities in reservoirs as compared with the lake was confirmed. Many ectoparasite groups were rare and most of the digenean parasites using molluscs as their intermediate host were absent from the reservoirs due to the inability of molluscs to tolerate the acidic water. The only digenean parasite found in the less acidic reservoir was Bunodera luciopercae. There were also species that preferred reservoirs as was expected. The protozoan ciliate Capriniana piscium benefiting acidic water and Acanthocephalus lucii, due to the abundance of its intermediate host, were most prevalent in the reservoir conditions.     

Effect of temperature on proteinase activities in intestinal chyme and mucosa of fish of different ecological groups

Effect of temperature on activities of proteinases in intestinal chyme and mucosa was studied in three fish species (pike-perch, zope, roach) belonging to different ecological groups by their nutrition type. There was revealed a significant difference of dependence of enzyme activities in chyme on temperature in the benthophage, roach (a higher level of relative activity in the range of lower temperatures and a wider zone of temperature optimum) as well as of values of apparent energy of activation of the protein hydrolysis process as compared with that in planktoand ichtyophages, zope and pike-perch, which indicates a significant effect of the enteral microbiota proteinases and of nutrition objects on characteristics of hydrolases functioning in fish intestine.     

Effect of temperature on proteinase activities in the intestinal chyme and the mucosa of various ecological fish groups

Effect of temperature on activities of proteinases in intestinal chyme and mucosa was studied in three fish species (pike-perch, zope, roach) belonging to different ecological groups by their type of feeding. There was revealed a significant difference of dependence of enzyme activities in chyme on temperature in the benthophage roach (a higher level of relative activity in the zone of lower temperatures and a larger zone of temperature optimum) as well as of values of apparent energy of activation of the protein hydrolysis process as compared with that in plankto- and ichthyophages--zope and pike-perch, which indicates a significant effect of the enteral microbiota proteinases and of nutrition objects on characteristics of hydrolases functioning in fish intestine.     

Reducing the allelopathic effect of Partheniumhysterophorus L. on wheat (Triticumaestivum L.) by Pseudomonasputida

The present study evaluates the role of Pseudomonas putida NBRIC19 in alleviating biotic stress of Parthenium hysterophorus (Parthenium) in Triticum aestivum. Due to presence of Parthenium there was 43.76, 53.08 and 78.65% inhibition in root length, shoot length and dry weight of wheat respectively. This inhibition was recovered when P. putida NBRIC19 treatment resulted in 52.29, 28.73 and 76.31% increase in root length, shoot length and dry weight respectively as compared to control. P. putida NBRIC19 was able to form more biofilm under toxic environment of allelochemicals and enhanced expression of stress responsive genes in wheat. Inoculated wheat plants showed lower activity of catalase and ascorbate peroxidase under biotic stress of Parthenium indicating that inoculated plants felt less stress as compared to uninoculated plants. Microbial community structure in bacterized and nonbacterized wheat rhizosphere in presence and absence of Parthenium, was investigated using Biolog. There was significant increase in microbial diversity in P. putida NBRIC19 bacterized wheat rhizosphere. Functional microbial diversity revealed that P. putida NBRIC19 had shifted the microflora in such a manner that utilization of phytotoxic allelochemicals increased to lessen its toxic effect and finally it resulted in better growth of wheat in presence of Parthenium. Principal component analysis showed that microbial community function in nonbacterized wheat rhizosphere in presence (WPC) and absence (WC) of Parthenium is totally different from each other but due to P. putida NBRIC19 treatment there was close clustering of WPT and WT indicating a total shift in microbial community structure.     

The effect of temperature and body size on digestive efficiency in Fundulus heteroclitus (L.)

The digestive efficiency of temperature acclimated mummichogs, Fundulus heteroclitus (L.), was determined using the amphipod Orchestia grillus Bosc as prey. Experiments were conducted on three size groups of mummichogs (<1 g, 1–3 g, > 3 g) at 5, 13, 21, and 29 °C. No difference was found in digestive efficiency by different sizes of mummichogs. There was, however, a statistically significant difference in efficiency over the range of acclimation temperatures, with the efficiencies being temperature independent from 13 to 29 °C and dropping slightly at 5 °C. From 13 to 29 °C, digestive efficiencies were the maximum possible. Temperatures in this range are normal late spring, summer, and early fall habitat temperatures in Maine estuaries. The ability to maintain a maximum efficiency of digestion over this 16°C temperature range allows mummichogs to get the maximum amount of energy from their prey during the time of year when they are utilizing substantial energy for growth (somatic and gonadal, and for activity (foraging and mating). The digestive efficiency at 5 °C was only about 13.5% less than at 21 and 29 °C. This drop is probably of little ecological or energetic significance, so that mummichogs are actually able to absorb food energy across their alimentary tract relatively independent of acclimation temperature over a 24 °C range.     

Schneeammern (Passerina nivalis L.) und Zwergtrappe (Otis tetrax L.) in Krain 1914/1915

Ohne Zusammenfassung     

Gamma radiation and interspecific hybridization in jute ( Corchorus capsularis L. and C. olitorius L.)

Although numerous attempts have been made during the last five decades, no hybrids combining the qualities of the two commercially most important species have been released so far. Dry seeds of Corchorus capsularis L. var. D-154 and Corchorus olitorius L. var. C.G. were irradiated with gamma rays of various intensities from 70 Kr. to 100 Kr. and were sown in the field. Abnormal plants of the first generation showing bilobed and crinkled characters in their leaves induced by gamma rays were chosen as male parents. 300 crosses of different combinations were made. In all 120 fruits developed into maturity. All the seeds failed to germinate except those from the crosses ♀ C.G. (0 Kr.) × ♂ D-154 (80 Kr.) and ♀ D-154 (0 Kr.) × ♂ C.G. (70 Kr.). F₁ plants from the cross ♀ C.G. (0 Kr.) × ♂ D-154 (80 Kr.) inherited the bilobed character of the male parent whereas the plants from the other cross failed to show any sign of inheritance of the male parent. This indicated that the plants from the cross ♀ C.G. (0 Kr.) × ♂ D-154 (80 Kr.) were hybrids. These hybrids attained a greater height than the controls and were highly fertile.     

Copia and Gypsy retrotransposons activity in sunflower (Helianthus annuus L.)

Background  

Retrotransposons are heterogeneous sequences, widespread in eukaryotic genomes, which refer to the so-called mobile DNA. They resemble retroviruses, both in their structure and for their ability to transpose within the host genome, of which they make up a considerable portion. Copia- and Gypsy-like retrotransposons are the two main classes of retroelements shown to be ubiquitous in plant genomes. Ideally, the retrotransposons life cycle results in the synthesis of a messenger RNA and then self-encoded proteins to process retrotransposon mRNA in double stranded extra-chromosomal cDNA copies which may integrate in new chromosomal locations.     

Tolerances of Nauplii of Balanus balanoides (L.) and Elminius modestus (Darwin) exposed to cyclical temperature fluctuations

1. 1.|Newly-released larvae of both E. modestus and B. balanoides show similar tolerances to steady temperature levels.

2. 2.|Both species show an ability to withstand a wider range of temperatures when subjected to cyclic thermal shocks.

3. 3.|E. modestus shows a greater tolerance to short-term thermal shocks than B. balanoides.

Isolation of pure compound R/J/3 from Pluchea indica (L.) Less. and its anti-amoebic activities against Entamoeba histolytica

The plant Pluchea indica is known for its anti-inflammatory, anti-ulcer, anti-pyretic, hypoglycemic, diuretic and anti-microbial activities besides many other pharmacological activities. We have isolated and purified seven compounds from the methanolic root extract of this plant by column chromatography. The compounds were identified by spectroscopic analyses. The anti-amoebic activities of the pure compound R/J/3 was investigated against the HM1 strain of Entamoeba histolytica. The compound, R/J/3 showed the most pronounced anti-proliferative activity at a dose of 50 microg/ml. It also showed a marked activity on cell lysis of trophozoites, 4h after administration. The cell lytic activity was compared with metronidazole (5 microg/ml) as positive control.     

The effect of adrenaline on potentials in the isolated gills of the flounder (Platichthys flesus L.)

Summary A technique is described for simultaneously measuring perfusion pressure and transepithelial potentials in isolated perfused gills.In this preparation the potentials measured in external media of Ringer or sea water were both reduced by 4 mV to 5 mV in the presence of 10^–6 M adrenaline. This effect was reversed by 10^–5 M phentolamine in both situations; 10^–5 M propanolol was without effect (Figs. 2, 3). Both potentials were reduced by oxygen lack (Figs. 1, 6).The preparations showed inconsistent vasomotor responses to adrenaline but 10^–5 M acetylcholine consistently produced an increase in branchial vascular resistance (Figs. 7, 8).It is suggested that adrenaline directly inhibits the branchial ion extrusion pump via a mechanism involving -adrenergic receptors. It is further suggested that the biogenic potential produced by the activity of the branchial ion pump makes a significant contribution to the total potential in sea water. The significance of these findings in relation to other work is discussed.     

The morphology and histology of the pineal organ in roach, Rutilus rutilus (L.)

The pineal organ in the roach, Rutilus rutilus (L.), is covered by a semi-transparent area, the pineal window. Beneath this the pineal is attached to a long robust stalk, lying just under the parietal bone. The pineal is attached to the brain through the dorsal sac. Three cell types have been identified histologically. These are the sensory cells, supporting cells and the ganglia cells. The inner segment of the sensory cells respond to PAS and AF staining, while the remaining cells respond to Orange G, LG, or Acid Fuchsin. The evidence suggests that the roach pineal may have a dual photosensory and glandular function.     

The decline of a roach Rutilus rutilus (L.) population in Chew Valley Lake

A series of nettings for roach in Chew Valley Lake carried out by members of the Zoology Department, Bristol University, has revealed a marked decline in the population between 1965 and 1968. Fish from the main Lake were found to be heavily parasitized with Ligula intestinalis (L.) while those from the inflow pool (Herriott's Pool) were practically free from infection. It is considered that the decline of the roach can be linked to the incidence of Ligula , but that clean fish from the inflow pool may provide breeding stock and maintain the production of fry, which serve as food for the trout.     

Influence of predation risk on individual competitive ability and growth in Eurasian perch, Perca fluviatilis

We studied the potential influence of predation risk on the competitive ability and habitat use of foraging perch and the effect of these interactions on growth. Groups of four similar-sized young-of-the-year perch were in visual contact with a piscivorous perch during feeding. The fry had the choice of vegetation and open habitat, with food presented in the open habitat. Competitive ability, defined as proportion of prey attacks, varied between perch individuals and was unaffected by predation risk. The variation in proportion of prey attacks was affected by relative size within each replicate group, despite small size differences (±1 mm), with the largest individual being a better competitor than the smallest ones. The degree of boldness, measured as the proportion of time spent in the open habitat, was significantly related to both competitive ability and prey attack order. Observations of aggressive behaviour indicated a possible occurrence of interference competition, which may contribute to the appearance of different competitive abilities between individuals within a group of perch. A significant correlation was found between competitive ability and growth. Growth variation within groups was not affected by predation risk.     

Characterization of glycolytic initial metabolites and enzyme activities in developing sunflower (Helianthus annuus L.) seeds

Unlike other oilseeds (e.g. Arabidopsis), developing sunflower seeds do not accumulate a lot of starch and they rely on the sucrose that comes from the mother plant to synthesise lipid precursors. Between 10 and 25 days after flowering (DAF), when sunflower seeds form and complete the main period of storage lipid synthesis, the sucrose content of seeds is relatively constant. By contrast, the glucose and fructose content falls from day 20 after flowering and it is always lower than that of sucrose, with glucose being the minor sugar at the end of the seed formation. By studying the apparent kinetic parameters and the activity of glycolytic enzymes in vitro, it is evident that all the components of the glycolytic pathway are present in the crude seed extract. However, in isolated plastids important enzymatic activities are missing, such as the glyceraldehyde-3-phosphate dehydrogenase, involved in the conversion of glyceraldehyde 3-phosphate into 1,3-biphospho-glycerate, or the enolase that converts 2-phosphoglycerate into phosphoenolpyruvate. Hence, phosphoenolpyruvate or one of its derivatives, like pyruvate and malate from the cytosol, may be the primary carbon sources for lipid biosynthesis. Accordingly, the glucose-6-P imported into the plastid is likely to be used in the pentose phosphate pathway to produce the reducing power for lipid biosynthesis in the form of NADPH. Data from crude seed extracts indicate that enolase activity increased during seed formation, from 16 days after flowering, and that this activity was well correlated with the period of storage lipid synthesis. In addition, while the presence of some glycolytic enzymes increased during lipid synthesis, others decreased, remained constant, or displayed irregular temporal behaviour.     

The influence of acclimation and experimental temperature on glutamate dehydrogenase of carp red lateral muscle (Cyprinus carpio L.)

The dependence of the reaction catalysed by carp red lateral muscle glutamate-dehydrogenase on acclimation and experimental temperature was studied. In addition to quantitative aspects of enzyme temperature compensation, the influence of temperature conditions on kinetic characteristics of the enzyme protein is reported. Results are discussed with respect to temperature capacity adaptation (acclimation).