Ecophysiology Dotaz Zobrazit nápovědu
1st ed. xi, 287 s., čb. obr.
- MeSH
- obratlovci MeSH
- Konspekt
- Biologické vědy
- NLK Obory
- biologie
Testate amoebae (TA) are a group of free-living protozoa, important in ecology and paleoecology. Testate amoebae taxonomy is mainly based on the morphological features of the shell, as examined by means of light microscopy or (environmental) scanning electron microscopy (SEM/ESEM). We explored the potential applications of confocal laser scanning microscopy (CLSM), two photon excitation microscopy (TPEM), phase contrast, differential interference contrast (DIC Nomarski), and polarization microscopy to visualize TA shells and inner structures of living cells, which is not possible by SEM or environmental SEM. Images captured by CLSM and TPEM were utilized to create three-dimensional (3D) visualizations and to evaluate biovolume inside the shell by stereological methods, to assess the function of TA in ecosystems. This approach broadens the understanding of TA cell and shell morphology, and inner structures including organelles and endosymbionts, with potential implications in taxonomy and ecophysiology.
Pollution monitoring series
XIII, 366 s. : il. ; 24 cm
The aim of this study was to assess the phylogenetic relationships, ecology and ecophysiological characteristics of the dominant planktic algae in ice-covered lakes on James Ross Island (northeastern Antarctic Peninsula). Phylogenetic analyses of 18S rDNA together with analysis of ITS2 rDNA secondary structure and cell morphology revealed that the two strains belong to one species of the genus Monoraphidium (Chlorophyta, Sphaeropleales, Selenastraceae) that should be described as new in future. Immotile green algae are thus apparently capable to become the dominant primary producer in the extreme environment of Antarctic lakes with extensive ice-cover. The strains grew in a wide temperature range, but the growth was inhibited at temperatures above 20 °C, indicating their adaptation to low temperature. Preferences for low irradiances reflected the light conditions in their original habitat. Together with relatively high growth rates (0.4-0.5 day(-1)) and unprecedently high content of polyunsaturated fatty acids (PUFA, more than 70% of total fatty acids), it makes these isolates interesting candidates for biotechnological applications.
- MeSH
- biodiverzita * MeSH
- Chlorophyta klasifikace genetika metabolismus MeSH
- fytoplankton klasifikace genetika izolace a purifikace metabolismus MeSH
- fyziologická adaptace MeSH
- jezera MeSH
- ledový příkrov * MeSH
- nenasycené mastné kyseliny metabolismus MeSH
- RNA ribozomální 18S genetika MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Antarktida MeSH
Survival at high latitude requires the capability to cope with seasonally imposed stress, such as low winter temperatures or large temperature fluctuations. The Colorado potato beetle, Leptinotarsa decemlineata, is an invasive pest of potato that has rapidly spread from low latitudes to higher latitudes. During the last 30 years, a decrease in range expansion speed is apparent in Europe. We use a comparative approach to assess whether this could be due to an inability of L. decemlineata to cope with the harsher winters encountered at high latitude, when compared to two native northern chrysomelid beetles with similar overwintering ecology. We investigated several cold-tolerance-related physiological traits at different time points during winter. Cold tolerance followed a latitudinal pattern; the northern species were more tolerant to short-term subzero temperatures than the invasive L. decemlineata. The other northern species, the knotgrass leaf beetle, Chrysolina polita, was found to tolerate internal freezing. Interestingly, the pattern for overwinter survival at 5°C was the opposite and higher in L. decemlineata than the northern species and could be related to behavioral differences between species in overwintering location selection and a potential physiological trade-off between tolerance to cold shock and to chronic cold exposure. Furthermore, while the northern species accumulated large amounts of different sugars and polyols with probable cryoprotectant functions, none were detected in L. decemlineata at high concentrations. This lack of cryoprotectant accumulation could explain the difference in cold tolerance between the species and also suggests that a lack of physiological capacity to tolerate low temperatures could slow further latitudinal range expansion of L. decemlineata.
- MeSH
- aklimatizace MeSH
- brouci fyziologie MeSH
- chování zvířat MeSH
- druhová specificita MeSH
- ekosystém MeSH
- nízká teplota * MeSH
- roční období MeSH
- rozšíření zvířat * MeSH
- zavlečené druhy MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
- Geografické názvy
- Evropa MeSH
Red snow is a well-known phenomenon caused by microalgae thriving in alpine and polar regions during the melting season. The ecology and biodiversity of these organisms, which are adapted to low temperatures, high irradiance and freeze-thaw events, are still poorly understood. We compared two different snow habitats containing two different green algal genera in the European Alps, namely algae blooming in seasonal rock-based snowfields (Chlamydomonas nivalis) and algae dominating waterlogged snow bedded over ice (Chlainomonassp.). Despite the morphological similarity of the red spores found at the snow surface, we found differences in intracellular organization investigated by light and transmission electron microscopy and in secondary pigments investigated by chromatographic analysis in combination with mass spectrometry. Spores ofChlainomonassp. show clear differences fromChlamydomonas nivalisin cell wall arrangement and plastid organization. Active photosynthesis at ambient temperatures indicates a high physiological activity, despite no cell division being present. Lipid bodies containing the carotenoid astaxanthin, which produces the red color, dominate cells of both species, but are modified differently. While inChlainomonassp. astaxanthin is mainly esterified with two fatty acids and is more apolar, inChamydomonas nivalis, in contrast, less apolar monoesters prevail.
- MeSH
- biologické pigmenty fyziologie MeSH
- buněčná stěna chemie ultrastruktura MeSH
- Chlamydomonas fyziologie ultrastruktura MeSH
- ekosystém MeSH
- fotosyntéza fyziologie MeSH
- hmotnostní spektrometrie MeSH
- nízká teplota MeSH
- roční období MeSH
- sníh mikrobiologie MeSH
- světlo MeSH
- xanthofyly fyziologie MeSH
- zmrazování MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
- Geografické názvy
- Evropa MeSH
A new rhabdocoel of the genus Syndesmis Silliman, 1881 (Umagillidae) is described from the intestine of the New Zealand sea urchin Evechinus chloroticus (Valenciennes, 1846) Mortensen, 1943a. This new species, Syndesmis kurakaikina n. sp., is morphologically distinct and can easily be recognised by its very long (±1 mm) stylet and its bright-red colour. In addition to providing a formal description, we present some observations on reproduction and life history of this new species. Fecundity is comparable to that of other umagillids and the rate of egg production and development increases with temperature. Hatching in this species is induced by intestinal fluids of its host. Relevant to global warming, we assessed the effect of temperature on survival, fecundity, and development. The tests indicate that Syndesmis kurakaikina n. sp. is tolerant of a wide range of temperatures (11-25 °C) and that its temperature optimum lies between 18.0 and 21.5 °C. Egg viability is, however, significantly compromised at the higher end of this temperature range, with expelled egg capsules often being deformed and showing increasingly lower rates of hatching. Given this, a rise in global temperature might increase the risk of Syndesmis kurakaikina n. sp. infecting new hosts and would possibly facilitate the spread of these endosymbionts.
- Publikační typ
- časopisecké články MeSH
Variation in xylem vessel diameter is one of the most important parameters when evaluating plant water relations. This review provides a synthesis of the ecophysiological implications of variation in lumen diameter together with a summary of our current understanding of vessel development and its endogenous regulation. We analyzed inter-specific variation of the mean hydraulic vessel diameter (Dv ) across biomes, intra-specific variation of Dv under natural and controlled conditions, and intra-plant variation. We found that the Dv measured in young branches tends to stay below 30 µm in regions experiencing winter frost, whereas it is highly variable in the tropical rainforest. Within a plant, the widest vessels are often found in the trunk and in large roots; smaller diameters have been reported for leaves and small lateral roots. Dv varies in response to environmental factors and is not only a function of plant size. Despite the wealth of data on vessel diameter variation, the regulation of diameter is poorly understood. Polar auxin transport through the vascular cambium is a key regulator linking foliar and xylem development. Limited evidence suggests that auxin transport is also a determinant of vessel diameter. The role of auxin in cell expansion and in establishing longitudinal continuity during secondary growth deserve further study.
Due to their ecological, physiological, and molecular adaptations to low and varying temperatures, as well as varying seasonal irradiances, polar non-marine eukaryotic microalgae could be suitable for low-temperature biotechnology. Adaptations include the synthesis of compounds from different metabolic pathways that protect them against stress. Production of biological compounds and various biotechnological applications, for instance, water treatment technology, are of interest to humans. To select prospective strains for future low-temperature biotechnology in polar regions, temperature and irradiance of growth requirements (Q10 and Ea of 10 polar soil unicellular strains) were evaluated. In terms of temperature, three groups of strains were recognized: (i) cold-preferring where temperature optima ranged between 10.1 and 18.4°C, growth rate 0.252 and 0.344 · d-1 , (ii) cold- and warm-tolerating with optima above 10°C and growth rate 0.162-0.341 · d-1 , and (iii) warm-preferring temperatures above 20°C and growth rate 0.249-0.357 · d-1 . Their light requirements were low. Mean values Q10 for specific growth rate ranged from 0.7 to 3.1. The lowest Ea values were observed on cold-preferring and the highest in the warm-preferring strains. One strain from each temperature group was selected for PN and RD measurements. The PN :RD ratio of the warm-preferring strains was less affected by temperature similarly as Q10 and Ea. For future biotechnological applications, the strains with broad temperature tolerance (i.e., the group of cold- and warm-tolerating and warm-preferring strains) will be most useful.
- MeSH
- fotosyntéza MeSH
- mikrořasy * MeSH
- prospektivní studie MeSH
- půda MeSH
- teplota MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Aquatic Utricularia species usually grow in standing, nutrient-poor humic waters. They take up all necessary nutrients either directly from the water by rootless shoots or from animal prey by traps. The traps are hollow bladders, 1-6 mm long with elastic walls and have a mobile trap door. The inner part of the trap is densely lined with quadrifid and bifid glands and these are involved in the secretion of digestive enzymes, resorption of nutrients and pumping out the water. The traps capture small aquatic animals but they also host a community of microorganisms considered as commensals. How do these perfect traps function, kill and digest their prey? How do they provide ATP energy for their demanding physiological functions? What are the nature of the interactions between the traps and the mutualistic microorganisms living inside as commensals? In this mini review, all of these questions are considered from an ecophysiologist's point of view, based on the most recent literature data and unpublished results. A new concept on the role of the commensal community for the plants is presented.
