Dual bloom of green algae and purple bacteria in an extremely shallow soda pan

Extremophiles - In April 2014, dual bloom of green algae and purple bacteria occurred in a shallow, alkaline soda pan (Kiskunság National Park, Hungary). The water was only 5 cm deep,...     

Homothallic life cycle in the diploid red yeast Xanthophyllomyces dendrorhous (Phaffia rhodozyma)

Sexual activity was induced in the basidiomyceteous Phaffia rhodozyma (Xanthophyllomyces dendrorhous) by depletion of nitrogen from the culture medium. This activity involved both mating between two yeast cells and the formation of basidiospores. Mating is possibly started by a G1 phase arrest of the cell cycle, as in other yeasts. The life cycle exhibited homothallic features. Crosses between genetically marked strains, and pulse-field gel electrophoresis of the chromosomal DNA of cells derived from individual spores revealed evidence of karyogamy, meiosis and even recombination. The segregation ratio in tetrads pointed to diploid vegetative cells, which formed tetraploid zygotes and the immediate meiosis then gave rise to diploid progenies again. Apart from the type strain Phaffia rhodozyma CBS 5905, all the examined strains were able to sporulate.     

Electrophoretic karyotypes of Phaffia rhodozyma strains

Abstract Electrophoretic karyotypes of strains from the astaxanthin-producing yeast Phaffia rhodozyma have been established. Intact chromosomal DNA molecules released from protoplasts were separated by orthogonal field alternation gel electrophoresis (OFAGE) and contour clamped homogeneous electric field (CHEF). Both small and large chromosomal DNA molecules were resolved simultaneously by optimizing the running conditions. Electrophoretic karyotypes among the Phaffia isolates examined differed significantly. Seven to thirteen chromosomal bands, ranging in size from 0.83 Mb to 3.50 Mb, were resolved, giving total genome sizes of about 15.4 to 23.2 Mb. Ribosomal DNA has been assigned to chromosomal bands using a heterologous gene probe.     

Achillicin,the first proazulene from Achillea millefolium

Achillicin, the major proazulene (prochamazulene) of Achillea millefolium L. ssp. collina Becker has been isolated and identified as 8-acetoxyartabsin. It is the first proazulene reported for the genus Achillea and has not been found previously in plants.     

Drosophila Nimrod proteins bind bacteria

Engulfment of foreign particles by phagocytes is initiated by the engagement of phagocytic receptors. We have previously reported that NimC1 is involved in the phagocytosis of bacteria in Drosophila melanogaster. We have identified a family of genes, the Nimrod gene superfamily, encoding characteristic NIM domain containing structural homologues of NimC1. In this work we studied the bacterium-binding properties of the Nimrod proteins by using a novel immunofluorescencebased flow cytometric assay. This method proved to be highly reproducible and suitable for investigations of the bacteriumbinding capacities of putative phagocytosis receptors. We found that NimC1, NimA, NimB1 and NimB2 bind bacteria significantly but differently. In this respect they are similar to other NIM domain containing receptors Eater and Draper.     

Trophic relationships between primary producers and fish yields in Lake Balaton

Relationships between chlorophyll a content of the water, the shoreline-length: water area ratio and the annual total fish yield as catch per unit effort (CUE: kg ha^–1 100 h^–1 as annual mean values) have been calculated by multivariable regression. The determination coefficient (r ² = 0.913) showed a significant dependence of fish yield on morphometry of different lake areas. Accordingly, fish carrying capacity of the open water areas, calculated from chlorophyll a content and S/A, ranged from 12 to 34%, but that of the littoral zone between 66 and 88%. These findings have also been supported by echo-sounding records of the horizontal distribution of fish.Bream (Abramis brama L.) contributes the majority (70–80%) of fish stock and yield. Its food mainly consists of zooplankton and benthic invertebrates in ratios that are widely variable with season and depend on the age of fish. Average daily food consumption of individuals (age group 3 + and over) varies between 2 and 5 g. Bream consumes two- to three-times more food in the SW basin than in the NE one. This means that the present stocks inhabiting areas from NE to SW consume annually 13249–20085 t yr^–1 of food. According to estimated calorific values, the annual energy consumption of local populations along the longitudinal axis of the lake varies between 93 and 141 kJ m^–2 yr^–1. The efficiency of energy transfer from primary producers to fish is low and varies from 0.04 to 0.1%.     

Oligotrophication of Lake Balaton over a 20-year period and its implications for the relationship between phytoplankton and zooplankton biomass

Hydrobiologia - Lake Balaton, the largest lake in Central Europe, underwent severe eutrophication from the 1960s to the 1990s, due to phosphorus loadings from external anthropogenic sources. The...