scholarly journals The Lichens’ Microbiota, Still a Mystery?

2021 ◽  
Vol 12 ◽  
Author(s):  
Maria Grimm ◽  
Martin Grube ◽  
Ulf Schiefelbein ◽  
Daniela Zühlke ◽  
Jörg Bernhardt ◽  
...  

Lichens represent self-supporting symbioses, which occur in a wide range of terrestrial habitats and which contribute significantly to mineral cycling and energy flow at a global scale. Lichens usually grow much slower than higher plants. Nevertheless, lichens can contribute substantially to biomass production. This review focuses on the lichen symbiosis in general and especially on the model species Lobaria pulmonaria L. Hoffm., which is a large foliose lichen that occurs worldwide on tree trunks in undisturbed forests with long ecological continuity. In comparison to many other lichens, L. pulmonaria is less tolerant to desiccation and highly sensitive to air pollution. The name-giving mycobiont (belonging to the Ascomycota), provides a protective layer covering a layer of the green-algal photobiont (Dictyochloropsis reticulata) and interspersed cyanobacterial cell clusters (Nostoc spec.). Recently performed metaproteome analyses confirm the partition of functions in lichen partnerships. The ample functional diversity of the mycobiont contrasts the predominant function of the photobiont in production (and secretion) of energy-rich carbohydrates, and the cyanobiont’s contribution by nitrogen fixation. In addition, high throughput and state-of-the-art metagenomics and community fingerprinting, metatranscriptomics, and MS-based metaproteomics identify the bacterial community present on L. pulmonaria as a surprisingly abundant and structurally integrated element of the lichen symbiosis. Comparative metaproteome analyses of lichens from different sampling sites suggest the presence of a relatively stable core microbiome and a sampling site-specific portion of the microbiome. Moreover, these studies indicate how the microbiota may contribute to the symbiotic system, to improve its health, growth and fitness.

2016 ◽  
Vol 48 (5) ◽  
pp. 545-557 ◽  
Author(s):  
Geir HESTMARK ◽  
François LUTZONI ◽  
Jolanta MIADLIKOWSKA

AbstractThe identity and phylogenetic placement of photobionts associated with two lichen-forming fungi, Umbilicaria spodochroa and Lasallia pustulata were examined. These lichens commonly grow together in high abundance on coastal cliffs in Norway, Sweden and Finland. The mycobiont of U. spodochroa reproduces sexually through ascospores, and must find a suitable algal partner in the environment to re-establish the lichen symbiosis. Lasallia pustulata reproduces mainly vegetatively using symbiotic propagules (isidia) containing both symbiotic partners (photobiont and mycobiont). Based on DNA sequences of the internal transcribed spacer region (ITS) we detected seven haplotypes of the green-algal genus Trebouxia in 19 pairs of adjacent thalli of U. spodochroa and L. pustulata from five coastal localities in Norway. As expected, U. spodochroa associated with a higher diversity of photobionts (seven haplotypes) than the mostly asexually reproducing L. pustulata (four haplotypes). The latter was associated with the same haplotype in 15 of the 19 thalli sampled. Nine of the lichen pairs examined share the same algal haplotype, supporting the hypothesis that the mycobiont of U. spodochroa might associate with the photobiont ‘pirated’ from the abundant isidia produced by L. pustulata that are often scattered on the cliff surfaces. Up to six haplotypes of Trebouxia were found within a single sampling site, indicating a low level of specificity of both mycobionts for their algal partner. Most photobiont strains associated with species of Umbilicaria and Lasallia, including samples from this study, represent phylogenetically closely related taxa of Trebouxia grouped within a small number of main clades (Trebouxia sp., T. simplex/T. jamesii, and T. incrustata+T. gigantea). Three of the photobiont haplotypes were found only in U. spodochroa thalli.


2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Brahma N. Singh ◽  
Garima Pandey ◽  
Prateeksha ◽  
J. Kumar

With the advent of green pharmaceuticals, the secondary metabolites derived from plants have provided numerous leads for the development of a wide range of therapeutic drugs; however the discovery of new drugs with novel structures has declined in the past few years. Cryptogams including lichens, bryophytes, and pteridophytes represent a group of small terrestrial plants that remain relatively untouched in the drug discovery process though some have been used as ethnomedicines by various tribes worldwide. Studies of their secondary metabolites are recent but reveal unique secondary metabolites which are not synthesized by higher plants. These compounds can have the potential to develop more potential herbal drugs for prevention and treatment of diseases The present article . deals with the secondary metabolites and pharmacological activities of cryptogams with an objective to bring them forth as potential source of biodynamic compounds of therapeutic value.


2021 ◽  
Vol 3 (9) ◽  
Author(s):  
Katalin Hubai ◽  
Nora Kováts ◽  
Gábor Teke

AbstractAtmospheric particulate matter (PM) is one of the major environmental concerns in Europe. A wide range of studies has proved the ecotoxic potential of atmospheric particles. PM exerts chemical stress on vegetation by its potentially toxic constituents; however, relatively few studies are available on assessing phytotoxic effects under laboratory conditions. In our study, aqueous extract of particulate matter was prepared and used for treatment. Experiment was following the procedure defined by the No. 227 OECD Guideline for the Testing of Chemicals: Terrestrial Plant Test. Tomato (Lycopersicon esculentum Mill.) plants were used; elucidated toxicity was assessed based on morphological and biochemical endpoints such as biomass, chlorophyll-a and chlorophyll-b, carotenoids, and protein content. Biomass reduction and protein content showed a clear dose–effect relationship; the biomass decreased in comparison with the control (100%) in all test groups (TG) at a steady rate (TG1: 87.73%; TG2: 71.77%; TG3: 67.01%; TG4: 63.63%). The tendency in protein concentrations compared to the control was TG1: 113.61%; TG2: 148.21% TG3: 160.52%; TG4: 157.31%. However, pigments showed a ‘Janus-faced’ effect: nutrient content of the sample caused slight increase at lower doses; actual toxicity became apparent only at higher doses (chlorophyll-a concentration decrease was 84.47% in TG4, chlorophyll-b was 77.17%, and finally, carotene showed 83.60% decrease in TG4).


Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1022
Author(s):  
Rashid G. Bikbaev ◽  
Ivan V. Timofeev ◽  
Vasiliy F. Shabanov

Optical sensing is one of many promising applications for all-dielectric photonic materials. Herein, we present an analytical and numerical study on the strain-responsive spectral properties of a bioinspired sensor. The sensor structure contains a two-dimensional periodic array of dielectric nanodisks to mimic the optical behavior of grana lamellae inside chloroplasts. To accumulate a noticeable response, we exploit the collective optical mode in grana ensemble. In higher plants, such a mode appears as Wood’s anomaly near the chlorophyll absorption line to control the photosynthesis rate. The resonance is shown persistent against moderate biological disorder and deformation. Under the stretching or compression of a symmetric structure, the mode splits into a couple of polarized modes. The frequency difference is accurately detected. It depends on the stretch coefficient almost linearly providing easy calibration of the strain-sensing device. The sensitivity of the considered structure remains at 5 nm/% in a wide range of strain. The influence of the stretching coefficient on the length of the reciprocal lattice vectors, as well as on the angle between them, is taken into account. This adaptive phenomenon is suggested for sensing applications in biomimetic optical nanomaterials.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
L. Paulina Maldonado-Ruiz ◽  
Saraswoti Neupane ◽  
Yoonseong Park ◽  
Ludek Zurek

Abstract Background The lone star tick (Amblyomma americanum), an important vector of a wide range of human and animal pathogens, is very common throughout the East and Midwest of the USA. Ticks are known to carry non-pathogenic bacteria that may play a role in their vector competence for pathogens. Several previous studies using the high throughput sequencing (HTS) technologies reported the commensal bacteria in a tick midgut as abundant and diverse. In contrast, in our preliminary survey of the field collected adult lone star ticks, we found the number of culturable/viable bacteria very low. Methods We aimed to analyze the bacterial community of A. americanum by a parallel culture-dependent and a culture-independent approach applied to individual ticks. Results We analyzed 94 adult females collected in eastern Kansas and found that 60.8% of ticks had no culturable bacteria and the remaining ticks carried only 67.7 ± 42.8 colony-forming units (CFUs)/tick representing 26 genera. HTS of the 16S rRNA gene resulted in a total of 32 operational taxonomic units (OTUs) with the dominant endosymbiotic genera Coxiella and Rickettsia (> 95%). Remaining OTUs with very low abundance were typical soil bacterial taxa indicating their environmental origin. Conclusions No correlation was found between the CFU abundance and the relative abundance from the culture-independent approach. This suggests that many culturable taxa detected by HTS but not by culture-dependent method were not viable or were not in their culturable state. Overall, our HTS results show that the midgut bacterial community of A. americanum is very poor without a core microbiome and the majority of bacteria are endosymbiotic.


2018 ◽  
Vol MA2018-01 (31) ◽  
pp. 1917-1917
Author(s):  
Dongho Lee ◽  
Kyoung-Shin Choi

Producing hydrogen via solar water splitting using a photoelectrochemical cell (PEC) persists as one of the most exciting research topics in the field of solar fuels. The construction of efficient PECs requires the integration of multiple components including a photoanode, a photocathode, an oxygen evolution catalyst, and a hydrogen evolution catalyst. Therefore, the compatibility and stability of all of these elements in a given operating condition are crucial. When the stability of a semiconductor electrode used as the photoanode or photocathode is limited in an acidic or basic condition which is optimum for the operation of the other components, a thin protective layer has been deposited on the semiconductor surface to prevent its chemical dissolution. Surface coating of a thin and conformal TiO2 layer has been proven to be successful for protecting photoelectrodes since TiO2 is chemically and electrochemically stable in a wide range of pH conditions under both anodic and cathodic conditions. In order to prevent the semiconductor surface from coming into direct contact with the corrosive electrolyte, complete coverage of the photoelectrode with TiO2 is required. At the same time, the TiO2 layer should be thin enough not to interfere with the charge transport properties of the photoelectrode. As a result, atomic layer deposition (ALD) has been the only successful tool used to date to produce an effective protective layer. However, the slow processing time and economic viability of ALD methods motivated us to develop an inexpensive and facile solution-based synthesis method for the deposition of high quality TiO2 coating layers. In this presentation, we report a new electrochemical method to deposit a thin and conformal TiO2 layer on nanoporous BiVO4 that has an intricate, high surface area morphology. BiVO4 is a promising n-type photoanode material with a relatively low bandgap (2.4~2.5 eV). However, its usage has been limited to neutral and mildly basic conditions (pH 5~9) because it is chemically unstable in strongly acidic and basic conditions. Our method allows for the deposition of a 5~6 nm thick TiO2 layer on BiVO4 within 1 min and the resulting BiVO4/TiO2 electrodes exhibit chemical stability in basic solutions (pH 12~13). Sulfite oxidation measurements of BiVO4 and BiVO4/TiO2 electrodes show that the thin TiO2 protective layer does not significantly reduce the hole transfer to the electrolyte. Finally, we demonstrate the photoelectrochemical stability of the BiVO4/TiO2 electrode for photoelectrochemical water oxidation in basic solutions by coupling the BiVO4/TiO2 electrode with appropriate oxygen evolution catalysts.


2009 ◽  
Vol 106 (17) ◽  
pp. 7251-7256 ◽  
Author(s):  
Atsushi Fukushima ◽  
Miyako Kusano ◽  
Norihito Nakamichi ◽  
Makoto Kobayashi ◽  
Naomi Hayashi ◽  
...  

In higher plants, the circadian clock controls a wide range of cellular processes such as photosynthesis and stress responses. Understanding metabolic changes in arrhythmic plants and determining output-related function of clock genes would help in elucidating circadian-clock mechanisms underlying plant growth and development. In this work, we investigated physiological relevance of PSEUDO-RESPONSE REGULATORS (PRR 9, 7, and 5) in Arabidopsis thaliana by transcriptomic and metabolomic analyses. Metabolite profiling using gas chromatography–time-of-flight mass spectrometry demonstrated well-differentiated metabolite phenotypes of seven mutants, including two arrhythmic plants with similar morphology, a PRR 9, 7, and 5 triple mutant and a CIRCADIAN CLOCK-ASSOCIATED 1 (CCA1)-overexpressor line. Despite different light and time conditions, the triple mutant exhibited a dramatic increase in intermediates in the tricarboxylic acid cycle. This suggests that proteins PRR 9, 7, and 5 are involved in maintaining mitochondrial homeostasis. Integrated analysis of transcriptomics and metabolomics revealed that PRR 9, 7, and 5 negatively regulate the biosynthetic pathways of chlorophyll, carotenoid and abscisic acid, and α-tocopherol, highlighting them as additional outputs of pseudo-response regulators. These findings indicated that mitochondrial functions are coupled with the circadian system in plants.


2009 ◽  
Vol 9 (1) ◽  
pp. 3207-3241 ◽  
Author(s):  
K. J. Pringle ◽  
K. S. Carslaw ◽  
D. V. Spracklen ◽  
G. M. Mann ◽  
M. P. Chipperfield

Abstract. Empirical relationships that link cloud droplet number (CDN) to aerosol number or mass are commonly used to calculate global fields of CDN for climate forcing assessments. In this work we use a sectional global model of sulfate and sea-salt aerosol coupled to a mechanistic aerosol activation scheme to explore the limitations of this approach. We find that a given aerosol number concentration produces a wide range of CDN concentrations due to variations in the shape of the aerosol size distribution. On a global scale, the dependence of CDN on the size distribution results in regional biases in predicted CDN (for a given aerosol number). Empirical relationships between aerosol number and CDN are often derived from regional data but applied to the entire globe. In an analogous process, we derive regional "correlation-relations" between aerosol number and CDN and apply these regional relations to calculations of CDN on the global scale. The global mean percentage error in CDN caused by using regionally derived CDN-aerosol relations is 20 to 26%, which is about half the global mean percentage change in CDN caused by doubling the updraft velocity. However, the error is as much as 25–75% in the Southern Ocean, the Arctic and regions of persistent stratocumulus when an aerosol-CDN correlation relation from the North Atlantic is used. These regions produce much higher CDN concentrations (for a given aerosol number) than predicted by the globally uniform empirical relations. CDN-aerosol number relations from different regions also show very different sensitivity to changing aerosol. The magnitude of the rate of change of CDN with particle number, a measure of the aerosol efficacy, varies by a factor 4. CDN in cloud processed regions of persistent stratocumulus is particularly sensitive to changing aerosol number. It is therefore likely that the indirect effect will be underestimated in these important regions.


2020 ◽  
Author(s):  
Bronwen L. Konecky ◽  
Nicholas P. McKay ◽  
Olga V. Churakova (Sidorova) ◽  
Laia Comas-Bru ◽  
Emilie P. Dassié ◽  
...  

Abstract. Reconstructions of global hydroclimate during the Common Era (CE; the past ~ 2000 years) are important for providing context for current and future global environmental change. Stable isotope ratios in water are quantitative indicators of hydroclimate on regional to global scales, and these signals are encoded in a wide range of natural geologic archives. Here we present the Iso2k database, a global compilation of previously published datasets from a variety of natural archives that record the stable oxygen (δ18O) or hydrogen (δ2H) isotopic composition of environmental waters, which reflect hydroclimate changes over the CE. The Iso2k database contains 756 isotope records from the terrestrial and marine realms, including: glacier and ground ice (205); speleothems (68); corals, sclerosponges, and mollusks (145); wood (81); lake sediments and other terrestrial sediments (e.g., loess) (158); and marine sediments (99). Individual datasets have temporal resolutions ranging from sub-annual to centennial, and include chronological data where available. A fundamental feature of the database is its comprehensive metadata, which will assist both experts and non-experts in the interpretation of each record and in data synthesis. Key metadata fields have standardized vocabularies to facilitate comparisons across diverse archives and with climate model simulated fields. This is the first global-scale collection of water isotope proxy records from multiple types of geological and biological archives. It is suitable for evaluating hydroclimate processes through time and space using large-scale synthesis, model-data intercomparison and (paleo)data assimilation. The Iso2k database is available for download at: https://doi.org/10.6084/m9.figshare.11553162 (McKay and Konecky, 2020).


2021 ◽  
Author(s):  
Jan De Pue ◽  
José Miguel Barrios ◽  
Liyang Liu ◽  
Philippe Ciais ◽  
Alirio Arboleda ◽  
...  

<p>Over the past decades, land surface models have evolved into advanced tools which comprise detailed process descriptions and interactions at a broad range of scales. One of the challenges in these models is the accurate simulation of plant phenology. It is a key element at the nexus of the simulated hydrological and carbon cycle, where the leaf area index (LAI) plays a major role in flux partitioning, water balance and gross primary production.<br>In this study, three well-established models are used to simulate the intrinsically coupled fluxes of water, energy and carbon from terrestrial vegetation. ORCHIDEE, ISBA-CC and the LSA-SAF algorithm each have a different approach to represent plant phenology. Whereas ISBA-CC has a fairly simple biomass allocation scheme to represent the phenological cycle, ORCHIDEE relies on a dedicated phenology module, and LSA-SAF is driven by remote-sensed forcing variables, such as LAI. Simulations were performed for a wide range of hydro-climatic biomes and plant functional types at field scale. The simulated fluxes were validated using eddy-covariance measurements, and the simulated phenology was compared to remote-sensed observations.<br>These models are tools to extrapolate leaf-level processes to global scale climate predictions. The origin of the parameters controlling phenology-induced variability in these models ranges from plant-scale lab experiments to global-scale calibration. The aim of this study is to investigate the key parameters controlling phenology-induced variability in these models.</p>


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