Changes in diatom assemblages in the profundal sediments of two large oligohumic lakes in eastern Finland

Sedimentary diatom assemblages in two large oligotrophic clear-water lakes were analysed, to assess their present ecological state and possible eutrophication due to diffuse nutrient loading. The lakes Pyhäjärvi and Puruvesi (Finnish lake district) are proportionally large for their catchment areas which accounts for their long retention times (ca 7 and 11 yr) and oligohumic character. Pyhäjärvi was studied by pairwise comparison of surface sediment diatom assemblages collected in 1985 and 1990 at 12 sites from different parts of the lake. In Puruvesi, the stratigraphy of diatoms was analysed in two short cores from 8 m and 32 m depths.The diatom assemblages of the two lakes are rather similar, and quite distinct from the assemblages of the mesohumic large lakes of the area. Cyclotella kuetzingiana is the most common planktonic dia- tom, but Aulacoseira ambigua abounds in Pyhäjärvi at sites with local sources of eutrophication. A diverse assemblage of benthic forms, especially Fragilaria and Achnanthes spp. characterizes the shallow bottoms in both lakes.There was little change within the short-core diatom profiles of Puruvesi, but the floral composition of the 8-m and 32-m sites differed markedly. The 8-m site, with 60–70% of benthic forms, represents illuminated bottom, on which much of the buried algae have lived in situ, while the deeper site is true profundal, dominated by sedimented planktonic algae.In Pyhäjärvi there was a slight increase in the benthic diatoms from 1985 to 1990, coinciding with increased phosphorus and chlorophyll concentrations as well as Secchi depth lowering. We interprete this observation as a very early step of eutrophication, of which first the sessile algal communities of the illuminated bottom areas have benefited.     

Molecular basis of chromosome banding

Silver and mercury ions are known to react with the bases of nucleic acids in solution. At low cation/base ratios Ag+ has an affinity for GC pairs in DNA, whereas Hg++ is preferentially bound to AT-rich nucleic acids. We have used fluorometry to measure the effect of these cations on the fluorescence intensity of preformed complexes of acranil and DNA in solution. The results are: 1) Ag+ enhances the fluorescence intensity presumably by affecting the dye intercalated in the vicinity of GC-pairs. 2) The addition of Hg++ leads to a quenching of the fluorescence intensity of the complex at low ion/base ratios, suggesting an effect on the dye molecules bound to AT pairs. At high GC-content of the nucleic acid, slight enhancement of the fluorescence intensity occurs with Hg++. 3) With both metals there is a correlation between base content of DNA and effect on the intensity of fluorescence indicating base specificity of the dye-polymer interaction.     

Lignification related enzymes in Picea abies suspension cultures

Activity of a number of enzymes related to lignin formation was measured in a Picea abies (L) Karsten suspension culture that is able to produce native-like lignin into the nutrient medium. This cell culture is an attractive model for studying lignin formation, as the process takes place independently of the complex macromolecular matrix of the native apoplast. Suspension culture proteins were fractionated into soluble cellular proteins, ionically and covalently bound cell wall proteins and nutrient medium proteins. The nutrient medium contained up to 5.3% of total coniferyl alcohol peroxidase (EC 1.11.1.7) activity and a significant NADH oxidase activity that is suggested to be responsible for hydrogen peroxide (H2O2) production. There also existed some malate dehydrogenase (EC 1.1.1.37) activity in the apoplast of suspension culture cells (in ionically and covalently bound cell wall protein fractions), possibly for the regeneration of NADH that is needed for peroxidase-catalysed H2O2 production. However, there is no proof of the existence of NADH in the apoplast. Nutrient medium peroxidases could be classified into acidic, slightly basic and highly basic isoenzyme groups by isoelectric focusing. Only acidic peroxidases were found in the covalently bound cell wall protein fraction. Several peroxidase isoenzymes across the whole pI range were detected in the protein fraction ionically bound to cell walls and in the soluble cellular protein fraction. One laccase-like isoenzyme with pI of approximately 8.5 was found in the nutrient medium that was able to form dehydrogenation polymer from coniferyl alcohol in the absence of H2O2. The total activity of this oxidase towards coniferyl alcohol was, however, several orders of magnitude smaller than that of peroxidases in vitro. According to 2D 1H-13C correlation NMR spectra, most of the abundant structural units of native lignin and released suspension culture lignin are present in the oxidase produced dehydrogenation polymer but in somewhat different amounts compared to peroxidase derived synthetic lignin preparations. A coniferin beta-glucosidase (EC 3.2.1.21) was observed to be secreted into the culture medium.     

Some observations on the effect of Daflon (micronized purified flavonoid fraction of Rutaceae aurantiae) in bancroftian filarial lymphoedema

BACKGROUND: Morbidity management is a core component of the global programme for the elimination of lymphatic filariasis. In a double-blind clinical trial, the tolerability and efficacy of Daflon (500 mg) + DEC (25 mg) or DEC (25 mg) alone, twice daily for 90 days, was studied in 26 patients with bancroftian filarial lymphoedema. RESULTS: None of the patients in either drug group reported any adverse reaction throughout the treatment period (90 days). Haematological and biochemical parameters were within normal limits and there was no significant difference between the pre-treatment (day 0) and post-treatment (day 90) values. The group receiving Daflon showed significant reduction in oedema volume from day 90 (140.6 PlusMinus; 18.8 ml) to day 360 (71.8 PlusMinus; 20.7 ml) compared to the pre-treatment (day 0, 198.4 PlusMinus; 16.5 ml) value. This accounted for a 63.8% reduction in oedema volume by day 360 (considering the pre-treatment (day 0) as 100%). In the DEC group, the changes in oedema volume (between day 1 and day 360) were not significant when compared to the pre-treatment (day 0) value. The percentage reduction at day 360 was only 9%, which was not significant (P > 0.05). CONCLUSION: This study has shown that Daflon (500 mg, twice a day for 90 days) is both safe and efficacious in reducing oedema volume in bancroftian filarial lymphoedema. Further clinical trials are essential for strengthening the evidence base on the role of this drug in the morbidity management of lymphatic filariasis.     

Direct intracardiac injection of umbilical cord-derived stromal cells and umbilical cord blood-derived endothelial cells for the treatment of ischemic cardiomyopathy

The development of new therapeutic strategies is necessary to reduce the worldwide social and economic impact of cardiovascular disease, which produces high rates of morbidity and mortality. A therapeutic option that has emerged in the last decade is cell therapy. The aim of this study was to compare the effect of transplanting human umbilical cord-derived stromal cells (UCSCs), human umbilical cord blood-derived endothelial cells (UCBECs) or a combination of these two cell types for the treatment of ischemic cardiomyopathy (IC) in a Wistar rat model. IC was induced by left coronary artery ligation, and baseline echocardiography was performed seven days later. Animals with a left ventricular ejection fraction (LVEF) of ≤40% were selected for the study. On the ninth day after IC was induced, the animals were randomized into the following experimental groups: UCSCs, UCBECs, UCSCs plus UCBECs, or vehicle (control). Thirty days after treatment, an echocardiographic analysis was performed, followed by euthanasia. The animals in all of the cell therapy groups, regardless of the cell type transplanted, had less collagen deposition in their heart tissue and demonstrated a significant improvement in myocardial function after IC. Furthermore, there was a trend of increasing numbers of blood vessels in the infarcted area. The median value of LVEF increased by 7.19% to 11.77%, whereas the control group decreased by 0.24%. These results suggest that UCSCs and UCBECs are promising cells for cellular cardiomyoplasty and can be an effective therapy for improving cardiac function following IC.     

Dual target strategy: combining distinct non‐dopaminergic treatments reduces neuronal cell loss and synergistically modulates l‐DOPA‐induced rotational behavior in a rodent model of Parkinson's disease

The glutamate metabotropic receptor 5 (mGluR5) and the adenosine A_2A receptor (A_2AR) represent major non‐dopaminergic therapeutic targets in Parkinson's disease (PD) to improve motor symptoms and slow down/revert disease progression. The 6‐hydroxydopamine rat model of PD was used to determine/compare the neuroprotective and behavioral impacts of single and combined administration of one mGluR5 antagonist, 2‐methyl‐6‐(phenylethynyl)pyridine (MPEP), and two A_2AR antagonists, (E)‐phosphoric acid mono‐[3‐[8‐[2‐(3‐methoxyphenyl)vinyl]‐7‐methyl‐2,6‐dioxo‐1‐prop‐2‐ynyl‐1,2,6,7‐tetrahydropurin‐3‐yl]propyl] (MSX‐3) and 8‐ethoxy‐9‐ethyladenine (ANR 94). Chronic treatment with MPEP or MSX‐3 alone, but not with ANR 94, reduced the toxin‐induced loss of dopaminergic neurons in the substantia nigra pars compacta. Combining MSX‐3 and MPEP further improved the neuroprotective effect of either antagonists. At the behavioral level, ANR 94 and MSX‐3 given alone significantly potentiated l ‐DOPA‐induced turning behavior. Combination of either A_2AR antagonists with MPEP synergistically increased L‐DOPA‐induced turning. This effect was dose‐dependent and required subthreshold drug concentration, which per se had no motor stimulating effect. Our findings suggest that co‐treatment with A_2AR and mGluR5 antagonists provides better therapeutic benefits than those produced by either drug alone. Our study sheds some light on the efficacy and advantages of combined non‐dopaminergic PD treatment using low drug concentration and establishes the basis for in‐depth studies to identify optimal doses at which these drugs reach highest efficacy.

     

Sniper: improved SNP discovery by multiply mapping deep sequenced reads

SNP (single nucleotide polymorphism) discovery using next-generation sequencing data remains difficult primarily because of redundant genomic regions, such as interspersed repetitive elements and paralogous genes, present in all eukaryotic genomes. To address this problem, we developed Sniper, a novel multi-locus Bayesian probabilistic model and a computationally efficient algorithm that explicitly incorporates sequence reads that map to multiple genomic loci. Our model fully accounts for sequencing error, template bias, and multi-locus SNP combinations, maintaining high sensitivity and specificity under a broad range of conditions. An implementation of Sniper is freely available at .     

Diploidization in megagametophyte-derived cultures of the gymnosperm Larix decidua

Tested haploid embryogenic lines (n=12) of Larix dedicua Mill, initiated from megagametophyte tissue were maintained on half-strength LM medium without growth regulators. The cultures were analyzed for ploidy level after 1–9 years. All lines tested were found to have doubled (2n=24) their chromosome number at the end of the experiment, though there were a few lines that still gave occasional haploid counts. Flow cytometric data of embryogenic tissue confirmed these results. Protoplasts were stained in ethidium bromide, and cultured human leucocytes and chicken erythrocytes were used as internal standards. Haploid megagametophytes from immature seeds of L. decidua and known diploid culture lines of a related hybrid (L. x eurolepis) were also analyzed by flow cytometry. Haploid reference material had 12.3–13.6 pg DNA per cell, whereas formerly haploid callus lines had an average of 25.0 pg DNA per cell. The one exception was a known, genetically unstable line of L. decidua (34.8 pg DNA per cell). The diploid cell line of L. x eurolepis had 27.6 pg DNA per cell. The results show that spontaneous diploidization of megagametophyte lines is relatively rapid and that both haploid and dihaploid lines are embryogenic in larch.     

Molecular basis of chromosome banding

The effects of mouse satellite, main band and total DNA on the fluorescence intensity of quinacrine and of the bibenzimidazole derivative Hoechst 33258 were tested in solution. No significant differences were noticed between the double-stranded DNAs in spite of the 5% difference in AT-content between satellite and main band DNA. Single-stranded DNAs enhanced the fluorescence intensity of Hoechst 33258 far less than double-stranded DNAs. Having been denaturated and then reassociated the DNA fractions were intermediate in their enhancing effects on the fluorescence intensity of Hoechst 33258, the differences presumably being due to different degrees of reassociation. The effect of denatured and subsequently reassociated satellite DNA on the fluorescence intensity of quinacrine was similar to that of the native DNAs. Main band and total DNA quenched the fluorescence intensity of quinacrine more after denaturation-reassociation than it did when native. In the discussion the results are related to known cytological data.