CORRESPONDENCE BETWEEN PHYLOGENY AND MORPHOLOGY OF SNOWELLA SPP. AND WORONICHINIA NAEGELIANA,CYANOBACTERIA COMMONLY OCCURRING IN LAKES1

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.     

The plasma membrane of Streptococcus cremoris: isolation and partial characterization

Plasma membrane was isolated from Streptococcus cremoris using mutanolysin from a streptomycete as the cell wall-degrading enzyme and phenylmethylsulfonyl fluoride as protease inhibitor. The specific activity of membrane-bound enzyme, adenosine triphosphatase (ATPase), was 4 μmol/mg protein per min, which was 5–10 times higher than the activity found in other fractions obtained during the isolation procedure. The number of polypeptides in the plasma membrane was approximately 50 with molecular weights 13 500–100 000, minor changes in the polypeptide pattern were observed when the plasma membrane was isolated without a protease inhibitor. The chemical composition of the membrane preparation was 49.7% protein, 21.9% lipid, 5.1% aminosugars, 17.3% RNA and 0.03% DNA. Electron microscopic examination confirmed the membrane to be practically devoid of cell wall components. Our results indicate that the membrane integrity is well retained and therefore the membrane preparation is suitable for detailed studies on vectorial metabolism and its enzymes, e.g. ATPase.     

Distribution history and present status of the raccoon dog in Finland

The raccoon dog Nyctereutes procyonoides Gray was introduced from the Far East in several areas of the USSR, mainly the European part, in 1929–55. The first raccoon dogs were seen in Finland in the latter half of the 1930s, and by the mid-1950s, the frontier of the first regular observations had reached the most southeasterly parts of the country. Since then, the raccoon dog dispersed through southern and central Finland at an average annual rate of 20 km. The rate of population increase, as well as present density, has been highest in southern and southeastern Finland, and lowest in the northern parts of the distribution area. The northern limit of the distribution lies nowadays in southern Lapland, only a little further north than two decades earlier, when most of southern and central Finland was already inhabited.
The length of the growing season seems to explain most of the variation in the population density between the provinces. The longer the growing season, the better the raccoon dog manages; in southern Finland where the summers are longer, the juveniles have enough time to grow and gather fat reserves before hibernation. Therefore, many of them survive the winter and even breed in the following spring. In the north, in contrast, juvenile mortality is high during the first winter because of the short summer. The food availability, the yield of wild berries and the abundance of small rodents, is mostly responsible for the annual variation in the population density. Near the northern limit of the distribution, climate may also cause some of the annual variation in population density.     

Factors influencing odour production by actinomycetes

Odour production by actinomycete (Streptomyces spp.) strains isolated from hypereutrophic natural waters in which muddy odours in fish have occurred, were studied by the ISP (International Streptomyces Project) carbon utilization method. The streptomycete strains were isolated from water, bottom mud and aquatic plants. Nine different carbon sources were used. Odour character was determined by sniffing the cultures. Odour production varied depending on the strain and the carbon source used. Some of the strains produced similar odours in all media regardless of the carbon source. In other strains, the odour varied depending on the carbohydrate used. The total colony counts of actinomycetes may not necessarily indicate the role of actinomycetes in odour problems in the aquatic environment because the odour production by actinomycetes depends on environmental factors.     

Immunoreactivity for substance P in the gasserian ganglion, ophthalmic nerve and anterior segment of the rabbit eye

Summary The distribution of substance P (SP) immunofluorescence was investigated in the Gasserian ganglion, ophthalmic nerve and in the anterior segment of the rabbit eye. About one third of the nerve cell bodies in the Gasserian ganglion exhibited SP immunofluorescence, which was also observed in some nerve fibres of the ophthalmic nerve. In the cornea, some SP-positive iris contained numerous nerve fibres with SP immunofluorescence. In the sphincter area such fibres were circular, while the orientation of the SP fibres was radial in the dilator muscle. Both in the iris and in the ciliary body, the largest vessels were surrounded by nerves exhibiting SP immunofluorescence. A few nerve fibres also appeared in the stroma of the ciliary processes.     

Effect of denucleation and UV-irradiation on the subcellular morphology inMicrasterias

Summary The effects of the elimination of the nuclear control on the ultrastructure of the green algaMicrasterias torreyi. Bail, have been studied by using centrifugation for denucleation and lethal dose of UV-light. Centrifugated anucleate cells were fixed 7 and 26 hours after the treatment and the UV-treated cells 4 and 8 hours after the irradiation. Although both treatments eliminate the nuclear control and the treated cells resemble morphologically each other, yet there are differences in ultrastructure suggesting that they are also brought about by other factors than the presence of nucleus. Both the treatments cause accumulation of cell wall material in the tips of lobes. The cell wall shows unusual secondary thickening with electron dense spots embedded in the matrix. The denucleation retards the functional cycle of Golgi apparatus and the production of vesicles has stopped in the 26-hour-denucleated cells. It is possible that flat vesicle production is totally absent in denucleated cells.First the UV-treatment seems to activate the function of Golgi apparatus but later on the vesicle production almost stops. It seems to eliminate the production of large vesicles but not that of dark vesicles.Both the treatments cause deterioration of ER membranes and polysomes, and in consequence, probably inhibit protein synthesis.Unlike UV-irradiation, denucleation appears to destroy the microtubule system. Mitochondrial cristae have almost entirely vanished within 26 hours after denucleation. Effect of denucleation and UV-irradiation on the subcellular morphology inMicrasterias.     

Employing a Monte Carlo Algorithm in Newton-Type Methods for Restricted Maximum Likelihood Estimation of Genetic Parameters

Estimation of variance components by Monte Carlo (MC) expectation maximization (EM) restricted maximum likelihood (REML) is computationally efficient for large data sets and complex linear mixed effects models. However, efficiency may be lost due to the need for a large number of iterations of the EM algorithm. To decrease the computing time we explored the use of faster converging Newton-type algorithms within MC REML implementations. The implemented algorithms were: MC Newton-Raphson (NR), where the information matrix was generated via sampling; MC average information(AI), where the information was computed as an average of observed and expected information; and MC Broyden''s method, where the zero of the gradient was searched using a quasi-Newton-type algorithm. Performance of these algorithms was evaluated using simulated data. The final estimates were in good agreement with corresponding analytical ones. MC NR REML and MC AI REML enhanced convergence compared to MC EM REML and gave standard errors for the estimates as a by-product. MC NR REML required a larger number of MC samples, while each MC AI REML iteration demanded extra solving of mixed model equations by the number of parameters to be estimated. MC Broyden''s method required the largest number of MC samples with our small data and did not give standard errors for the parameters directly. We studied the performance of three different convergence criteria for the MC AI REML algorithm. Our results indicate the importance of defining a suitable convergence criterion and critical value in order to obtain an efficient Newton-type method utilizing a MC algorithm. Overall, use of a MC algorithm with Newton-type methods proved feasible and the results encourage testing of these methods with different kinds of large-scale problem settings.