scholarly journals Spatial and Temporal Ecological Uniqueness of Andean Diatom Communities Are Correlated With Climate, Geodiversity and Long-Term Limnological Change

2020 ◽  
Vol 8 ◽  
Author(s):  
Xavier Benito ◽  
Annika Vilmi ◽  
Melina Luethje ◽  
Maria Laura Carrevedo ◽  
Marja Lindholm ◽  
...  
Keyword(s):  
Diatom Communities ◽  
Ecological Uniqueness

scholarly journals In vitro resynthesis of lichenization reveals the genetic background of symbiosis-specific fungal-algal interaction in Usnea hakonensis.

2020 ◽  
Author(s):  
Mieko Kono ◽  
Yoshiaki Kon ◽  
Yoshihito Ohmura ◽  
Yoko Satta ◽  
Yohey Terai
Keyword(s):  
Molecular Mechanisms ◽  
Lichen Symbiosis ◽  
Fungal Partner ◽  
Wide Range ◽  
Lichen Thallus ◽  
Genetic Mechanisms ◽  
Ecological Uniqueness ◽  
Diversity Of Life

Abstract Background Symbiosis is central to ecosystems and has been an important driving force of the diversity of life. Close and long-term interactions are known to develop cooperative molecular mechanisms between the symbiotic partners and have often given them new functions as symbiotic entities. In lichen symbiosis, mutualistic relationships between lichen-forming fungi and algae and/or cyanobacteria produce unique features that make lichens adaptive to a wide range of environments. Although the morphological, physiological, and ecological uniqueness of lichens has been described for more than a century, the genetic mechanisms underlying this symbiosis are still poorly known.Results This study investigated the fungal-algal interaction specific to the lichen symbiosis using Usnea hakonensis as a model system. The whole genome of U. hakonensis, the fungal partner, was sequenced by using a culture isolated from a natural lichen thallus. Isolated cultures of the fungal and the algal partners were co-cultured in vitro for three months, and thalli were successfully resynthesized as visible protrusions. Transcriptomes of resynthesized and natural thalli (symbiotic states) were compared to that of isolated cultures (non-symbiotic state). Sets of fungal and algal genes up-regulated in both symbiotic states were identified as symbiosis-related genes.Conclusion From predicted functions of these genes, we identified genetic association with two key features fundamental to the symbiotic lifestyle in lichens. The first is establishment of a fungal symbiotic interface: (a) modification of cell walls at fungal-algal contact sites; and (b) production of a hydrophobic layer that ensheaths fungal and algal cells;. The second is symbiosis-specific nutrient flow: (a) the algal supply of photosynthetic product to the fungus; and (b) the fungal supply of phosphorous and nitrogen compounds to the alga. Since both features are widespread among lichens, our result may indicate important facets of the genetic basis of the lichen symbiosis.

Intra-annual fluctuations dominating temporal dynamics of benthic diatom assemblages in a Chinese mountainous river

2020 ◽  
Vol 56 ◽  
pp. 22
Author(s):  
Shuhan Guo ◽  
Fengzhi He ◽  
Tao Tang ◽  
Lu Tan ◽  
Qinghua Cai
Keyword(s):  
Community Dynamics ◽  
Environmental Changes ◽  
Temporal Dynamics ◽  
Multivariate Time Series ◽  
Multiple Scale ◽  
Benthic Diatom ◽  
Diatom Community ◽  
Diatom Communities ◽  
Mountainous River

Understanding temporal dynamics of community may provide insights on biological responses under environmental changes. However, our knowledge on temporal dynamics of river organisms is still limited. In the present study, we employed a multivariate time-series modeling approach with a long-term dataset (i.e. 72 consecutive months) to investigate temporal dynamics of benthic diatom communities in four sites located in a Chinese mountainous river network. We hypothesized that: (1) there are multi-scale temporal dynamics within the diatom community; (2) intra-annual fluctuations dominate the community dynamics; (3) diatom species composing the community respond distinctly to environmental changes. We found that intra-annual fluctuations with periodicities <12 months explained 8.1–16.1% of community variation. In contrast, fluctuations with periodicities of 13–36 months and 37–72 months only accounted for 1.1–5.9% and 2.8–9.7% of variance in diatom community dynamics, respectively. Taxa correlating significantly to each significant RDA axis (namely, RDA taxa group) displayed distinct temporal dynamics. Conductivity, total nitrogen, and pH were important to most RDA taxa groups across the four sites while their effects were group-specific. We concluded that intra-annual dynamics dominated temporal variation in diatom communities due to community responses to local environmental fluctuations. We suggest that long-term monitoring data are valuable for identifying multiple-scale temporal dynamics within biological communities.

Long-term and regional perspectives on recent change in lacustrine diatom communities in the tropical Andes

2018 ◽  
Vol 61 (2) ◽  
pp. 251-262 ◽  
Author(s):  
Sherilyn C. Fritz ◽  
Xavier Benito ◽  
Miriam Steinitz-Kannan
Keyword(s):  
Recent Change ◽  
Tropical Andes ◽  
Diatom Communities

Use of community-based indices to monitor eutrophication in European rivers

1998 ◽  
Vol 25 (1) ◽  
pp. 22-29 ◽  
Author(s):  
MARTYN G. KELLY
Keyword(s):  
Organic Pollution ◽  
Theoretical Framework ◽  
Community Based ◽  
Ecological Response ◽  
Upper Limit ◽  
Diatom Communities ◽  
The Uk ◽  
First Time

New legislation has encouraged regulatory biologists in the UK to examine the impacts of eutrophication in rivers for the first time. The principal tools for this have been new indices based on macrophyte and diatom communities. The use of such indices is placed within an appropriate theoretical framework. The importance of recognizing the upper limit of sensitivity of such indices, as well as factors such as organic pollution, which can confuse interpretation, is discussed. Despite their limitations, community-based indices are valuable tools for reconnaissance studies and, in the long-term, as indicators of the extent to which nutrient reductions have led to an ecological response. Some general guidelines for monitoring eutrophication in rivers are proposed.

Phosphorus–Limited Growth Dynamics of Lotic Periphytic Diatom Communities: Areal Biomass and Cellular Growth Rate Responses

1989 ◽  
Vol 46 (8) ◽  
pp. 1293-1301 ◽  
Author(s):  
Max L. Bothwell
Keyword(s):  
Growth Dynamics ◽  
Taxonomic Composition ◽  
Cellular Growth ◽  
Diatom Communities ◽  
Enrichment Experiments ◽  
Specific Growth Rates ◽  
Log Linear ◽  
The Relationship ◽  
Periphytic Diatom

Three long-term phosphate enrichment experiments were conducted at the Experimental Troughs Apparatus (EXTRA), South Thompson River British Columbia to determine the relationship between external orthophosphate (PO43−) concentration and peak areal biomass (PB) of periphytic diatom communities. Levels of PO43− which saturated PB were two orders of magnitude greater than those required to saturate specific growth rates in thin film periphyton communities of similar taxonomic composition. With PO43− additions between 0.1 to 1.0 μg P∙L−1, PB responded in a hyperbolic fashion, initially increasing rapidly, then showing signs of saturation PB continued to increase in a slow, linear manner above 1.0 μg P∙L−1. Maximum PB (PBmax) was calculated to occur at ca. 28 μg P∙L−1. At higher PO43− concentrations (> 30–50 μg P∙L−1) PB was no longer P limited. Below the saturation point, PB was approximated by a log–linear function of PO43−.

scholarly journals Ecological uniqueness of stream and lake diatom communities shows different macroecological patterns

2017 ◽  
Vol 23 (9) ◽  
pp. 1042-1053 ◽  
Author(s):  
Annika Vilmi ◽  
Satu Maaria Karjalainen ◽  
Jani Heino
Keyword(s):  
Diatom Communities ◽  
Ecological Uniqueness

scholarly journals In vitro resynthesis of lichenization reveals the genetic background of symbiosis-specific fungal-algal interaction in Usnea hakonensis

BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Mieko Kono ◽  
Yoshiaki Kon ◽  
Yoshihito Ohmura ◽  
Yoko Satta ◽  
Yohey Terai
Keyword(s):  
Molecular Mechanisms ◽  
Lichen Symbiosis ◽  
Fungal Partner ◽  
Wide Range ◽  
Lichen Thallus ◽  
Genetic Mechanisms ◽  
Ecological Uniqueness ◽  
Diversity Of Life

Abstract Background Symbiosis is central to ecosystems and has been an important driving force of the diversity of life. Close and long-term interactions are known to develop cooperative molecular mechanisms between the symbiotic partners and have often given them new functions as symbiotic entities. In lichen symbiosis, mutualistic relationships between lichen-forming fungi and algae and/or cyanobacteria produce unique features that make lichens adaptive to a wide range of environments. Although the morphological, physiological, and ecological uniqueness of lichens has been described for more than a century, the genetic mechanisms underlying this symbiosis are still poorly known. Results This study investigated the fungal-algal interaction specific to the lichen symbiosis using Usnea hakonensis as a model system. The whole genome of U. hakonensis, the fungal partner, was sequenced by using a culture isolated from a natural lichen thallus. Isolated cultures of the fungal and the algal partners were co-cultured in vitro for 3 months, and thalli were successfully resynthesized as visible protrusions. Transcriptomes of resynthesized and natural thalli (symbiotic states) were compared to that of isolated cultures (non-symbiotic state). Sets of fungal and algal genes up-regulated in both symbiotic states were identified as symbiosis-related genes. Conclusion From predicted functions of these genes, we identified genetic association with two key features fundamental to the symbiotic lifestyle in lichens. The first is establishment of a fungal symbiotic interface: (a) modification of cell walls at fungal-algal contact sites; and (b) production of a hydrophobic layer that ensheaths fungal and algal cells;. The second is symbiosis-specific nutrient flow: (a) the algal supply of photosynthetic product to the fungus; and (b) the fungal supply of phosphorous and nitrogen compounds to the alga. Since both features are widespread among lichens, our result may indicate important facets of the genetic basis of the lichen symbiosis.

scholarly journals In vitro resynthesis of lichenization reveals the genetic background of symbiosis-specific fungal-algal interaction in Usnea hakonensis.

2020 ◽  
Author(s):  
Mieko Kono ◽  
Yoshiaki Kon ◽  
Yoshihito Ohmura ◽  
Yoko Satta ◽  
Yohey Terai
Keyword(s):  
Molecular Mechanisms ◽  
Lichen Symbiosis ◽  
Fungal Partner ◽  
Wide Range ◽  
Lichen Thallus ◽  
Genetic Mechanisms ◽  
Ecological Uniqueness ◽  
Diversity Of Life

Abstract Background: Symbiosis is central to ecosystems and has been an important driving force of the diversity of life. Close and long-term interactions are known to develop cooperative molecular mechanisms between the symbiotic partners and have often given them new functions as symbiotic entities. In lichen symbiosis, mutualistic relationships between lichen-forming fungi and algae and/or cyanobacteria produce unique features that make lichens adaptive to a wide range of environments. Although the morphological, physiological, and ecological uniqueness of lichens has been described for more than a century, the genetic mechanisms underlying this symbiosis are still poorly known.Results: This study investigated the fungal-algal interaction specific to the lichen symbiosis using Usnea hakonensis as a model system. The whole genome of U. hakonensis, the fungal partner, was sequenced by using a culture isolated from a natural lichen thallus. Isolated cultures of the fungal and the algal partners were co-cultured in vitro for three months, and thalli were successfully resynthesized as visible protrusions. Transcriptomes of resynthesized and natural thalli (symbiotic states) were compared to that of isolated cultures (non-symbiotic state). Sets of fungal and algal genes up-regulated in both symbiotic states were identified as symbiosis-related genes.Conclusion: From predicted functions of these genes, we identified genetic association with two key features fundamental to the symbiotic lifestyle in lichens. The first is establishment of a fungal symbiotic interface: (a) modification of cell walls at fungal-algal contact sites; and (b) production of a hydrophobic layer that ensheaths fungal and algal cells;. The second is symbiosis-specific nutrient flow: (a) the algal supply of photosynthetic product to the fungus; and (b) the fungal supply of phosphorous and nitrogen compounds to the alga. Since both features are widespread among lichens, our result may indicate important facets of the genetic basis of the lichen symbiosis.

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