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1.
P. J. Vuorinen S. Peuranen M. Keinänen C. Tigerstedt J. Raitaniemi M. Rask 《Zeitschrift fur angewandte Ichthyologie》2004,20(3):217-224
The acute effects on perch and long‐term effects on whitefish were studied after liming one side of a lake [initial pH: 4.6–5.5; aluminium (Al): 29–54 μg L?1; Ca2+: 0.02–0.07 mmol L?1] that was divided into two parts with a plastic curtain. Some Al precipitation was observed on the gill surface of perch 1 day after liming; the concentration of plasma sodium of perch females in the limed side was also higher than in the acidic side. Nearly 6 months after liming, at the spawning time of whitefish, the plasma chloride concentration of whitefish in the limed side was higher and blood glucose concentration lower than in the acidic side. Four of five whitefish males from the limed side, but only one of five males and none of the five females from the acidic side, were ready to spawn. The growth of whitefish in the limed side was also more rapid. These changes illustrate that liming had no acute harmful effects on perch, and allowed whitefish to recover from acidity‐related physiological stress. 相似文献
2.
Pirjo Rajaniemi‐Wacklin Anne Rantala Maria. A. Mugnai Silvia Turicchia Stefano Ventura Jarka Komrkov Liisa Lepist Kaarina Sivonen 《Journal of phycology》2006,42(1):226-232
In this study, the first reported isolates of the genera Snowella and Woronichinia were characterized by 16S rRNA gene sequencing and morphological analysis. Phylogenetic studies and sequences for these genera were not available previously. By botanical criteria, the five isolated strains were identified as Snowella litoralis (Häyrén) Komárek et Hindák Snowella rosea (Snow) Elenkin and Woronichinia naegeliana (Unger) Elenkin. This study underlines the identification of freshly isolated cultures, since the Snowella strains lost the colony structure and were not identifiable after extended laboratory cultivation. In the 16S rRNA gene analysis, the Snowella strains formed a monophyletic cluster, which was most closely related to the Woronichinia strain. Thus, our results show that the morphology of the genera Snowella and Woronichinia was in congruence with their phylogeny, and their phylogeny seems to support the traditional botanical classification of these genera. Furthermore, the genera Snowella and Woronichinia occurred commonly and might occasionally be the most abundant cyanobacterial taxa in mainly oligotrophic and mesotrophic Finnish lakes. Woronichinia occurred frequently and also formed blooms in eutrophic Czech reservoirs. 相似文献
3.
R. A. Bodaly J. Vuorinen R. D. Ward M. Luczynski J. D. Reist 《Journal of fish biology》1991,38(1):37-51
The genetic relationships among New and Old World coregonid fishes were studied by electrophoresis. The genetic composition of 60 populations, representing perhaps nine commonly recognized species of Coregonus and Stenodus from Europe and North America was determined for 37 genetic loci. Six distinct genetic groups were evident. The first contained only populations of the inconnu, Stenodus leucichthys (Güldenstadt). The Nei genetic distance between Stenodus and Coregonus was 0.305, a relatively small value as compared to other salmonid inter-generic comparisons. The second genetic grouping contained the Arctic cisco, C. autumnalis (Pallas), the N. American lake cisco, C. artedii Lesueur, and the Irish pollan, C. autumnalis pollan Thompson. These three taxa appear to be conspecific on the basis of genetic distances. The third genetic grouping contained the European whitefish, C. lavaretus (L.), and the N. American lake whitefish, C. clupeaformis (Mitchill). European and lake whitefish may be conspecific. Lake whitefish from northwestern N. America were more closely related to European whitefish (genetic distance 0.038) than to lake whitefish from central N. America (genetic distance 0.098). The fourth group contained the broad whitefish, C. nasus (Pallas), which is perhaps more closely related to the European/lake whitefish groups than other coregonids. The fifth genetic grouping contained only the Asian endemic, C. peled (Gmelin), and the sixth contained the least cisco, C. sardinella Valenciennes, and vendace, C. albula (L.), which also appear to be conspecific. The widespread genetic groupings obtained for ciscoes indicate that they do not constitute a single closely related group within the genus Coregonus. 相似文献
4.
The effects of structural analogues, excitatory amino acids and certain drugs on spontaneous and potassium-stimulated exogenous taurine and GABA release were investigated in mouse cerebral cortex slices using a superfusion system. Spontaneous efflux of both amino acids was rather slow but could be enhanced by their uptake inhibitors. Taurine efflux was facilitated by exogenous taurine, hypotaurine, -alanine and GABA, whereas GABA, nipecotic acid and homotaurine effectively enhanced GABA release. The stimulatory potency of the analogues closely corresponded to their ability to inhibit taurine and GABA uptake, respectively, indicating that these efflux processes could be mediated by the carriers operating outwards. Glutamate induced GABA release, whereas taurine efflux was potentiated by aspartate, glutamate, cysteate, homocysteate and kainate. The centrally acting drugs, including GABA agonists and antagonists, as well as the proposed taurine antagonist TAG (6-aminomethyl-3-methyl-4H-1,2,4-benzothiadiazine-1,1-dioxide), had no marked effects on spontaneous taurine and GABA release. Potassium ions stimulated dosedependently both taurine and GABA release from the slices, the responses of taurine being strikingly slow but sustained. Exogenous GABA and nipecotic acid accelerated the potassium-stimulated GABA release, whereas picrotoxin and bicuculline were ineffective. The potassium-stimulated taurine release was unaltered or suppressed by exogenous taurine and analogues, differing in this respect from GABA release. The apparent magnitude of the depolarization-induced GABA release is thus influenced by the function of membrane transport sites, but the same conclusion cannot be drawn with regard to taurine. Haloperidol and imipramine were able to affect the evoked release of both taurine and GABA. 相似文献
5.
Contamination of the culture water by high densities of phantom midge larvae, Chaoborus sp. resulted in size diminution, retarded reproduction and decrease in the clutch size of D. pulex, and size diminution of D. magna. Furthermore, D. pulex suffered heavy mortality. The results are discussed in the context of the hypothesis that energy is expended in the formation of defensive cyclomorphic spines. Other hypotheses are also discussed. 相似文献
6.
In the subarctic moss Dicranum elongatum Schleich & Schwaegr., the level of total lipids and triacylglycerols (TAG) was high in late winter and spring and low in autumn and winter. Four-week exposure of field material to continuous light (135μmol m−2 s−1 ) at 1°C resulted in a considerable increase in the amount of TAG in the autumn material acclimated to low temperatures and rhythmic light in the field. In contrast, the same treatment did not cause any increase in TAG in the spring material, acclimated to low temperatures and continuous light in the field. Results from experiments, in which moss cultivated for 4 months at 9°C on 12-h photoperiods (135μmol m−2 s−1 ) was kept for 3 weeks at low temperatures (9°C and −3°C) either in continuous light (135 or 70 μmol m−2 s−1 ) or with 12-h photoperiods (135 μmol m−2 s−1 ), indicated that the TAG level was higher at higher light intensity. At 9°C it was also higher in continuous light of both intensities than in rhythmic light. These results strongly suggest that decreasing irradiance and decreasing daylength limits the accumulation of TAG in D. elongatum during autumn in the subarctic. 相似文献
7.
A significant difference in UDP glucuronyltransferase activity (with p-nitrophenol as an acceptor) was found in the liver and kidneys of homozygous Wistar and Gunn rats. There was also a significant difference in hepatic UDP glucuronyltransferase activity between homozygous Wistar and heterozygous Gunn rats when the enzyme preparations were first activated by adding surfactants to the reaction mixture. This determination of surfactant-activated UDP glucuronyltransferase can be used to distinguish Wistar rats from heterozygous Gunn rats. Other enzymes of the glucuronic acid pathway were also studied in the liver and kidneys of homozygous Wistar and Gunn rats, but no differences were found.This study has been supported by grants from the U.S. Public Health Service (AM-06018-09 and the National Research Council for Natural Sciences, Finland. 相似文献
8.
Annual variation in the abundance and size of heterotrophic nanoflagellates on the SW coast of Finland, the Baltic Sea 总被引:3,自引:0,他引:3
Annual variation and vertical distribution in the abundanceand cell volume of heterotrophic nanoflagellates (HNF) was studiedon the SW coast of Finland, the Baltic Sea. HNF cell numbersand mean cell volume varied annually from 90 to 104 cells ml1,and from 3 to 32 µm3, respectively, with maxima in earlysummer. The proportion of choanoflagellates in the HNF communitywas 023%. Statistical analysis revealed the verticaldifferences in HNF abundance to be insignificant, but verticaldifferences in the size structure of HNF communities were found,especially during thermal stratification. The majority (>80%)of HNF were small (maximum dimension 24 µm); theproportion of large (>7 µm) cells were only 24%of the HNF abundance. An empirical equation for the relationshipbetween HNF cell length and volume is presented, and the measurementof flagellate volume by epifluorescence microscopy is discussed. 相似文献
9.
Taurine is an important modulator of neuronal activity in the immature brain. In kittens, taurine deficiency causes serious dysfunction in the cerebellar and cerebral visual cortex. The processes of taurine transport in vitro were now studied for the first time in different brain areas in developing and adult cats. The uptake of taurine consisted initially of two saturable components, high- and low-affinity, in synaptosomal preparations from the developing cerebral cortex and cerebellum, but the high-affinity uptake component completely disappeared during maturation. The release of both endogenous and preloaded labeled taurine from brain slices measured in a superfusion system was severalfold stimulated with a slow onset by depolarizing K+ (50 mM) concentrations. K+ stimulation released markedly more taurine from the cerebral cortex, cerebellum and brain stem in kittens than in adult cats. The responses were largest in the cerebellum. Both uptake and release of taurine are thus highly efficient in the brain of kittens and may be of significance in view of the vulnerability of cats to taurine deficiency. 相似文献
10.
The cation requirements of [3H]taurine and [35S]hypotaurine uptake by cultured neuroblastoma C1300 cells were compared in Krebs-Ringer-Hepes-glucose medium. The uptakes were strictly sodium-dependent at both low and high taurine and hypotaurine concentrations. The omission of Ca2+ or Mg2+ ions affected uptakes only marginally. The optimal K+ concentration was equal to the physiological concentration, whereas abnormally high K+ levels inhibited similarly taurine and hypotaurine uptake. The sodium dependence curves of both uptakes were sigmoidal in character at low and high taurine and hypotaurine concentrations. Hill plots suggest that two Na+ ions are coupled with the transfer of one taurine or hypotaurine molecule into neuroblastoma cells. With respect to cation requirements taurine and hypotaurine transports are similar in cultured neuroblastoma cells and display features considered typical of the uptake of a neurotransmitter amino acid. 相似文献