The effect of temperature change on metabolism: separating biological and chemical reactions

Life-detection experiments carried out in extraterrestrial locations provided inconclusive results whether processes observed were biological or chemical. In this study, the typical effect of temperature on metabolic rates is described and a life-detection method that is easy to perform is proposed. The method comprises observing changes in microbial metabolic rates after temperature shift. The method was demonstrated by experiments on aquatic microorganisms in the Gulf of Gdansk (Baltic Sea). First experiment, in which temperature was shifted within the temperature range encountered at the sampling site, demonstrated a typical Q10 coefficient (2.84). The experiment in which temperature was shifted beyond the environmental temperature range provided an unexpectedly low Q10 coefficient (1.44), which indicated that excessive temperature exerted an inhibitory effect on metabolism. This response is not expected for chemical reactions, but it is typical for biological processes. In summary, a pair of properly-tailored experiments permitted separating biological and chemical reactions

Dynamics of oxygen consumption during the formation of the anoxic zone in aquatic environment

Anoxic environments and communities of anaerobic organisms are encountered in aquatic environments and biotechnological reactors. Because of their importance, they are continuously studied. In this study, the dynamics of oxygen removal were observed during experiments reproducing the formation of the anoxic zone. Seven experiments were performed in an aquarium (volume: 60 l) with bottom sediments and water collected from different aquatic environments (river, pond, eutrophic lake, sea). To exclude reaeration, the water was isolated from the air by a layer of liquid paraffin. Below the paraffin layer the water was periodically mixed with a stirrer and sampled for oxygen concentration. Initially, a high rate of oxygen consumption was observed. Later, at low oxygen concentrations, the oxygen removal rate switched to a much lower one. Anoxic conditions were observed after 4-20 days of incubation, depending on the experiment. The point at which the microbial community converted from aerobic respiration to anaerobic metabolism was distinct and was observed at an oxygen concentration of 0.26-1.41 mg/l, depending on the experiment. The experiments were accompanied by bacterial counts and analyses of ciliate communities. The study indicates how the disappearance of oxygen during anoxic zone formation should be modeled, and provides data on the oxygen removal rates associated with aerobic and anaerobic communities of microorganisms. DOI: http://dx.doi.org/10.5281/zenodo.144357

Dynamics of oxygen consumption during the formation of the anoxic zone in aquatic environment

Anoxic environments and communities of anaerobic organisms are encountered in aquatic environments and biotechnological reactors. Because of their importance, they are continuously studied. In this study, the dynamics of oxygen removal were observed during experiments reproducing the formation of the anoxic zone. Seven experiments were performed in an aquarium (volume: 60 l) with bottom sediments and water collected from different aquatic environments (river, pond, eutrophic lake, sea). To exclude reaeration, the water was isolated from the air by a layer of liquid paraffin. Below the paraffin layer the water was periodically mixed with a stirrer and sampled for oxygen concentration. Initially, a high rate of oxygen consumption was observed. Later, at low oxygen concentrations, the oxygen removal rate switched to a much lower one. Anoxic conditions were observed after 4-20 days of incubation, depending on the experiment. The point at which the microbial community converted from aerobic respiration to anaerobic metabolism was distinct and was observed at an oxygen concentration of 0.26-1.41 mg/l, depending on the experiment. The experiments were accompanied by bacterial counts and analyses of ciliate communities. The study indicates how the disappearance of oxygen during anoxic zone formation should be modeled, and provides data on the oxygen removal rates associated with aerobic and anaerobic communities of microorganisms. DOI: http://dx.doi.org/10.5281/zenodo.144357

Consensus on methods of development of clinical practice guidelines in oncology under the auspices of Maria Sklodowska-Curie National Research Institute of Oncology and the Agency for Health Technology Assessment and Tariff System

Introduction.As the changes leading to improvement of cancer care in Poland have shown the need to introduce clinical practice guidelines into the health care system, it has become clear that no methodological standard of the process for guidelines preparation has been established so far. The following process aims to present a unified and comprehensive clinical practice guidelines (CPGs) development methodology. Materials and methods.A review of globally recognised methods used by guideline development groups was prepared, informing the discussion during three plenary meetings and extensive consultations in writing. The resulting document was unanimously approved by a group of 24 methodologists and clinical experts, and has been formally recognized as a standard for CPGs development by the management of the National Institute of Oncology and the Agency for Health Technology Assessment and Tariff System. Results.Within the process, 43 recommendations were formulated to create unified and comprehensive rules for guideline development within the Polish healthcare system. Conclusions.The presented methods are consistent with the globally recognized tools and methods of guideline development, such as GRADE and ADAPTE, and follow quality criteria described by AGREE II. The process supports the development of high-quality guidelines within a resource-constrained setting by allowing to choose between adoption, adaptation, or de novo development of either the whole document of guidelines or particular recommendations

Significance of pelagic and benthic metabolism for the carbon budget of a shallow lake

Pelagic and benthic primary production and respiration were measured at an offshore station in the shallow, 1.2 m deep, polymictic Lake Gardno (Poland) to examine the role of the pelagic zone and the sediments in the overall carbon budget of this lake. The respiration rates in the sediments were within the same range of values as those in the pelagic zone. The results indicate that although the pelagic zone of the lake was net autotrophic (P:R = 2.46) based on annual cycles, total primary production to respiration (pelagic zone + sediments) was balanced, and the P:R ratio was 1.18. Thus, potentially only a small part of pelagic primary production is exported and buried in the sediments. The whole lake ecosystem does not act as an effective atmospheric CO2 sink. The balanced primary production to respiration ratio in the open water zone of the lake indicated that littoral production was most probably decomposed or buried within the littoral zone.Pelagic and benthic primary production and respiration were measured in a shallow, eutrophic lake to examine the role of the pelagic zone and the sediments in the overall carbon budget of the lake. The pelagic zone of the lake was net autotrophic. When the sediment primary production and respiration were taken into account both processes were balanced

The size structure of the <i>Mesodinium rubrum</i> population in the Gda&#x144;sk Basin

The ciliate Mesodinium rubrum Lohmann 1908 (=Myrionecta rubra Jankowski 1976) is an important phototrophic organism in the Gda&#x144;sk Basin. In June 2002 the vertical distribution and size structure of the M. rubrum population were studied. Its presence was generally observed in the whole water column (one exception was the anoxic near-bottom zone in the Gda&#x144;sk Deep) at all stations studied. Maximum abundance (18300 cells dm-3) was recorded at 26 m depth at the station located in the inner Gulf of Gda&#x144;sk. Analysis of the size structure of the counted organisms demonstrated the co-existence of small and large cells of M. rubrum in the upper layer of the water column and a gradual increase with depth of the prevalence of large specimens. This shows that at least two forms of M. rubrum exist in the region studied. Deep migrations are probably undertaken only by relatively large organisms

Nanoflagellates in the Gda&#x0144;sk Basin: coexistence between forms belonging to different trophic types

Nanoflagellates are important bacterivores, but their role isoften underestimated because forms capable of phagotrophy andcontaining chlorophyll (mixotrophs) are excluded from analyses.Research conducted in the coastal zone of the Gda&#x0144;sk Basin (BalticSea) revealed seasonal changes in the relationship between thebiomasses of small (1-8 &#x00B5;m) nanoflagellates with (NFChl+)and without chlorophyll (NFChl-). Three distinct patterns weredistinguished: (i) spring, when the biomass of NFChl+ was lowerthan that of NFChl-, (ii) summer and autumn, when NFChl+ weredominant (about 90%), and (iii) late autumn and winter, whenthe prevalence of NFChl+ was lower (71-79\%). Additional studiesshowed the existence of spatial differences in the compositionof the nanoflagellate community. These spatial differences werenot shaped by freshwater input. The possible importance of mixotrophicforms in the Gda&#x0144;sk Basin is discussed

Dependence between temperature and clearance rate of <i>Balanion comatum</i> Wulff

The dependence between temperature and clearance rate of the ciliate Balanion comatum Wulff 1919 was assessed in the coastal zone of the southern Baltic Sea. Five in situ experiments were carried out with the use of wheat starch as a surrogate of food particles. The clearance rate rose from 1.4 to 7.0 µl cell-1 h-1 with a temperature rise from 8 to 19°C. B. comatum preferred particles of size 1.9-4.4 µm, and the clearance rates calculated for the preferred particles were consistently higher than those measured for the whole range of particles ingested (Wilcoxon's signed rank test, p = 0.04). The exponential dependence between temperature and clearance rates for preferred particles was statistically significant (R2 = 0.86, p = 0.02) and enabled the Q10 coefficient to be calculated. This amounted to 2.9 and lay within the range of typical values. The linear dependence (also drawn for preferred particles) demonstrated a higher significance (R2 = 0.91, p = 0.02), indicating the linear dynamics of the process

Planktonic communities in a small post-peat reservoir (Ustka Forest District, Poland)

The aim of this study was to evaluate the present state of a small (area of 0.2 ha), shallow (mean depth of 2 m) and approximately 30-year-old post-peat reservoir located in Bruskowskie Bagno, a Baltic raised mire in northern Poland. The study was conducted during all seasons of the year (August 2019–July 2020). The reservoir was characterised by a yellow to brown water colour, low pH (5.4) and quite low conductivity (40.4 µS cm-1), which are the main features of dystrophic water bodies. Similar to natural, dystrophic lakes and ponds, the phytoplankton was mainly composed of mixotrophic species like Dinobryon sp. and Gonyostomum semen. The only numerous non-flagellate group within the phytoplankton was desmids, which indicated that the water was influenced by the mire. The reservoir was characterised by a high abundance of ciliates (annual mean of 55.6 cells ml-1) and a very high abundance of rotifers (annual mean of 3.72 ind. ml-1). Among ciliates, the most important were prostomatids, accounting for 53% of the mean annual ciliate abundance. The results of our study indicate that artificial, approximately 30-year-old, post-peat reservoir resembled a natural dystrophic water body