Phytoplankton biomass and chlorophyll-a in some shallow lakes in central Europe

Based on 388 parallel data of phytoplankton biomass and chlorophyll-a of two shallow lakes and two ponds, the following results were obtained:

1. Relative chlorophyll-a content of phytoplankton biomass varied between 0.08–1.88%; chlorophyll-a concentration showed great differences among lakes.
2. Significant correlations (r = 0.68–0.92) were established between phytoplankton biomass and chlorophyll-a concentration. The regression in the artificial ponds was non-linear.
3. In parallel with the increase of average cell volume, a decrease in relative chlorophyll-a content was observed. A significant correlation (r = + 0.83) between the two variables was found. Relative chlorophyll-a content of phytoplankton is a log-function of average cell volume.

     

Stir-up effect of wind on a more-or-less stratified shallow lake phytoplankton community,Lake Balaton,Hungary

Microstratification of phytoplankton in the large shallow Lake Balaton (Hungary) was studied during a 24 h period. Dissolved O₂ showed biological stratification; flagellates exhibited a definite circadian rhythm. In the middle of the investigation a heavy storm broke out which was followed by the disappearance of differences between different layers of water. Storm-induced destratification is described by cluster-analysis. Abundances of dominant species changed differently in connection with the storm. Numbers of Nitzschia sp. increased due to stirring up from the sediment surface. Numbers of single-celled or colony-forming species (Cyclotella comta, Crucigenia quadrata, Coelosphaerium kuetzingianum) practically did not change. Numbers of all the three dominant filamentous species (Aphanizomenon fos-aquae f. klebahnii, Lyngbya limnetica, Planctonema lauterbornii) significantly decreased, which might be attributed to an unknown loss process and was followed by a competitive displacement by algae of small cell size.     

Quantitative evaluation of gel electrophoretic patterns by videodensitometry

Videodensitometry based on television technique has been shown to be suitable for recording gel electrophoretic patterns. Its speed of operation is about 60 times as fast as that of conventional densitometers, whereas the patterns recorded are practically the same.     

Cyclization of 13beta-ethyl-3-methoxy-17beta-ol-8,14-seco-1,3,5(10),9-gonatetraen-14-one and its 17 acetate derivative.

13beta-Ethyl-3-methoxy-17beta-ol-8,14-seco-1,3,5(10),8-gonatetraen-14-one (IIIa) was isolated and its participation in the well-known acidic cyclization process was established.     

Methods for Cryopreservation of Guinea Fowl Sperm

Conservation of indigenous poultry species is an important part of the new Hungarian agricultural strategy. Semen cryopreservation is the most practical method for the long term storage of poultry genetic material. The objective was to compare four protocols for cryopreservation of guinea fowl sperm (slow and fast programmable, freezing in nitrogen vapor, and pellet) and three cryoprotectants (10% ethylene glycol, 6% dimethyl-formamide and 6% dimethyl-acetamide). The efficiency of the methods was examined by in vitro tests (subjective motility scoring, sperm concentration, morphological and live/dead sperm analysis with eosin-aniline staining). Thereafter, the two most promising methods were tested by artificial insemination of frozen-thawed semen (3 times a week for 3 weeks using 300 million spermatozoa/hen), followed by candling of incubated eggs, assessment of fertilization, embryonic death, and hatching rate. The survival rate of live, intact spermatozoa was greatest (p≤0.05) in pellet method and the slow programmable protocol (with 10% ethylene glycol) (28.6 and 23.5%). The two best protocols (based on in vitro assessment of post-thaw semen quality) were subsequently tested in vivo with artificial insemination. The pellet method yielded a 64% fertility rate compared to slow protocol with only 30% fertility. Regardless, both freezing protocols significantly increased embryonic deaths compared to the control group (16,7; 9,1 and 8,3%, respectively). During the 3-week in vivo trial, fertility increased and early embryonic death decreased over time. According to the results the guinea fowl sperm could tolerate the fast freezing in pellet better than the slower freezing rates and resulted acceptable fertility rate.     

Extracts and Steroids from the Edible Mushroom Hypholoma lateritium Exhibit Anti‐Inflammatory Properties by Inhibition of COX‐2 and Activation of Nrf2

Hypholoma lateritium is an edible macrofungus with a common distribution in Europe, North America, and the Far East. The aim of this study was to investigate the potential anti‐inflammatory effects of H. lateritium extracts and its isolated steroids: fasciculic acid B, fasciculol E, fasciculol C, lanosta‐7,9(11)‐diene‐12β,21α‐epoxy‐2α,3β,24β,25‐tetraol, fasciculol F, and demethylincisterol A2. Organic (hexane, chloroform and 50 % methanol) and water extracts of H. lateritium were subjected to in vitro assays to determine pro‐inflammatory protein levels, such as cyclooxygenase‐2 (COX‐2), cytosolic prostaglandin E2 synthase (cPGES), and antioxidant nuclear factor (erythroid‐derived 2)‐like 2 (Nrf2). Fungal extracts demonstrated significant activities on pro‐inflammatory protein levels with minor differences among the activities of the fractions of different polarities. All the compounds proved to exert notable inhibitory properties on COX‐2 and were capable to stimulate the Nrf2 pathway. Fungal extracts and the compounds exerted no cytotoxic activities on RAW 264.7 cells.     

Trait‐based diatom functional diversity as an appropriate tool for understanding the effects of environmental changes in soda pans

Saline lakes, among the most seriously endangered ecosystems, are threatened due to climate change and human activities. One valuable feature of these environments is that they constitute areas of high biodiversity. Ecologists are, therefore, under great pressure to improve their understanding of the effects of natural and anthropogenic disturbances on the biodiversity of saline lakes. In this study, a total of 257 samples from 32 soda pans in Central Europe between 2006 and 2015 were examined. The effects of environmental variables and of geographical and limnoecological factors on functional diversity were analyzed. Furthermore, the explanatory power of the trait‐based approach was assessed, and the applicability of the indices for biomonitoring purposes was determined. It was found that low habitat heterogeneity and harsh environments lead to the selection of a small number of suitable traits, and consequently, to a naturally low level of functional diversity. Anthropogenic activities enhance diversity at functional level due to the shift toward freshwater characteristics. On the regional scale, the effects of the region and status (natural, degraded, reconstructed) on diatom functional diversity were significant and more pronounced than that of the environmental and other limnoecological factors. The degree of variance found in functional diversity ascribed to environmental variables is five times greater in the case of the application of a trait‐based approach, than when a taxonomic one is employed in the literature. Each of the tested functional diversity indices was sensitive to the most important environmental variables. Furthermore, these were type‐specific and proved to be more complex indicators than taxonomic metrics. It is possible to suggest four functional diversity indices (FGR, FRic, FDis, and FDiv) which emphasize their independence from substrate and seasonal variations for ecological status assessment and conservation planning.     

Roadsides provide refuge for orchids: characteristic of the surrounding landscape

Seminatural habitats are declining throughout the world; thus, the role of small anthropogenic habitats in the preservation of plants is becoming increasingly appreciated. Here, we surveyed the orchid flora of roadside verges in five Central European countries (Austria, Hungary, Romania, Slovakia, and Slovenia) and tested how the surrounding landscape matrix affects the overall number of species and individuals, and also different functional groups of orchids. We found more than 2,000 individuals of 27 orchid species during our surveys. According to our results, the increasing coverage of agricultural and urban areas negatively affects both the number of orchid species and individuals on roadsides. Our study further suggests that differences in the surrounding habitats affect which species are found on roadsides, since the increasing coverage of grasslands or forested areas around orchid occurrences had a significant positive effect on the number of grassland or forest‐dwelling species and individuals, respectively. Most variance in orchid numerosity and diversity was explained by the cover of the suitable habitat types of the respective taxa in the surrounding landscape of the sampling points. This highlights the importance of roadsides acting as refugia for numerous species and valuable plant communities as well as in supporting biodiversity in general.     

Sphingobacterium pedocola sp. nov. a novel halotolerant bacterium isolated from agricultural soil

Antonie van Leeuwenhoek - A Gram-reaction-negative halotolerant bacterial strain, designated Ka21T, was isolated from agricultural soil and characterised using a polyphasic approach to determine...