Biology subjects

Wagner, M.

Publications and source records attributed to Wagner, M..

At least 55 records · Page 3Linked to original sources

bioRxiv2023

Plastic food packaging from five countries contains endocrine and metabolism disrupting chemicals

Plastics are complex chemical mixtures of polymers and various intentionally and non-intentionally added substances. Despite the well-established links between certain plastic chemicals (bisphenols, phthalates) and adverse health effects, the composition and toxicity of real-world mixtures of plastic chemicals is not well understood. To assess both, we analyzed the chemicals from 36 plastic food contact articles from five countries using nontarget high-resolution mass spectrometry and reporter gene assays for four nuclear receptors that represent key components of the endocrine and metabolic system. We found that chemicals activating the pregnane X receptor (PXR), peroxisome proliferator receptor gamma (PPAR{gamma}), estrogen receptor alpha (ER) and inhibiting the androgen receptor (AR) are prevalent in plastic packaging. We detected up to 9936 chemical features in a single product but found that each product has a rather unique chemical fingerprint. To tackle this chemical complexity, we used stepwise partial least squares regressions and prioritized and tentatively identified the chemical features associated with receptor activity. Our findings demonstrate that most plastic food packaging contains endocrine and metabolism disrupting chemicals. This shows that plastics are a relevant source of exposure to toxic chemicals and further supports the notion that plastic products designed for food contact cannot be considered safe. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=114 SRC="FIGDIR/small/559713v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@44be3borg.highwire.dtl.DTLVardef@1252a31org.highwire.dtl.DTLVardef@f522a2org.highwire.dtl.DTLVardef@1b4f8be_HPS_FORMAT_FIGEXP M_FIG C_FIG

pharmacology and toxicology↗

bioRxiv2023

A molecular toolbox to study progesterone receptor signaling

Progesterone receptor (PR) signaling is required for mammary gland development and homeostasis. A major bottleneck in studying PR signaling is the lack of sensitive assays to measure and visualize PR pathway activity both quantitatively and spatially. Here, we develop new tools to study PR signaling in human breast epithelial cells. First, we generate optimized Progesterone Responsive Element (PRE)-luciferase constructs and demonstrate that these new reporters are a powerful tool to quantify PR signaling activity across a wide range of progesterone concentrations in two luminal breast cancer cell lines, MCF7 and T47D. We also describe a fluorescent lentiviral PRE-GFP reporter as a novel tool to visualize PR signaling at the single-cell level. Our reporter constructs are sensitive to physiological levels of progesterone. Second, we show that low background signaling, and high levels of PR expression are a prerequisite for robustly measuring PR signaling. Increasing PR expression by transient transfection, stable overexpression in MCF7 or clonal selection in T47D, drastically improves both the dynamic range of luciferase reporter assays, and the induction of endogenous PR target genes as measured by qRT-PCR. We find that the PR signaling response differs per cell line, target gene and hormone concentration used. Taken together, our tools allow a more rationally designed approach for measuring PR signaling in breast epithelial cells.

cell biology↗

bioRxiv2023

Miniaturized CAR knocked onto CD3epsilon extends TCR function with CAR specificity under control of endogenous TCR signaling cascade

Immunotherapy using TCR and especially CAR transgenic T cells is a rapidly advancing field with the potential to become standard of care for the treatment of multiple diseases. While all current FDA approved CAR T cell products are generated using lentiviral gene transfer, extensive work is put into CRISPR/Cas mediated gene delivery to develop the next generation of safer and more potent cell products. One limitation of all editing systems is the size restriction of the knock-in cargo. Targeted integration under control of an endogenous promotor and/or signaling cascades opens the possibility to reduce CAR gene size to absolute minimum. Here we demonstrate that a first-generation CAR payload can be reduced to its minimum component - the antigen-binding domain - by targeted integration under control of the CD3{varepsilon} promoter generating a CAR-CD3{varepsilon} fusion protein that exploits the endogenous TCR signaling cascade. Miniaturizing CAR payload in this way results in potent CAR activity while simultaneously retaining the primary antigen recognition function of the TCR. Introducing CAR-specificity using a CAR binder only while maintaining endogenous TCR function may be an appealing design for future autologous CAR T cell therapies.

bioengineering↗

bioRxiv2023

Fornix fractional anisotropy mediates the association between Mediterranean diet adherence and memory four years later in older adults without dementia

Here, we investigated whether fractional anisotropy (FA) of hippocampus-relevant white-matter tracts mediates the association between baseline Mediterranean diet adherence (MeDiAd) and verbal episodic memory over four years. Participants were healthy older adults with and without subjective cognitive decline and patients with amnestic mild cognitive impairment from the DELCODE cohort study (n = 376; age: 71.47 {+/-} 6.09 years; 48.7% female). MeDiAd and diffusion data were obtained at baseline. Verbal episodic memory was assessed at baseline and four yearly follow-ups. The associations between baseline MeDiAd and white matter, and verbal episodic memorys mean and rate of change over four years were tested with latent growth curve modeling. Baseline MeDiAd was associated with verbal episodic memory four years later (95% confidence interval, CI [0.01, 0.32]) but not with its rate of change over this period. Baseline Fornix FA mediated - and, thus, explained - that association (95% CI [0.002, 0.09]). Fornix FA may be an appropriate response biomarker of Mediterranean diet interventions on verbal memory in older adults.

neuroscience↗

bioRxiv2022

Human TRMT2A methylates different components of the translation machinery and contributes to translation fidelity

Methyl-5-uridine (m5U) is one of the most abundant RNA modifications found in cytosolic tRNA. tRNA methyltransferase 2 homolog A (hTRMT2A) is the dedicated mammalian enzyme of m5U formation at tRNA position 54. However, its RNA binding specificity and functional role in the cell are not well understood. Here we dissected structural and sequence requirements for binding and methylation of its RNA targets. Specificity of tRNA modification by TRMT2A is achieved by a combination of modest binding preference and presence of a uridine in position 54 of tRNAs. Mutational analysis together with crosslinking experiments identified a large hTRMT2A-tRNA binding surface. Furthermore, complementing hTRMT2A interactome studies revealed that TRMT2A interacts with proteins involved in RNA biogenesis. Finally, we addressed the question of the importance of TRMT2A function by showing that its knockdown reduces translation fidelity. These findings extend the role of hTRMT2A beyond tRNA modification towards a role in translation.

biochemistry↗

bioRxiv2022

Ras-dependent RAF-MAPK hyperactivation by pathogenic RIT1 is a therapeutic target in Noonan syndrome-associated cardiac hypertrophy

RIT1 belongs to the family of Ras guanosine triphosphatases (GTPases) that regulate many aspects of signal transduction and are drivers of cancer and congenital disorders. RIT1 gain-of-function mutations are found in lung cancer, leukemia, and in the germline of Noonan syndrome individuals with an increased prevalence of cardiac hypertrophy and other congenital heart defects. Pathogenic RIT1 proteins evade proteasomal degradation and promote MEK/ERK mitogen-activated protein kinase (MAPK) hyperactivation, yet the mechanism remains poorly understood. Here we show that RAF kinases are putative mutant RIT1 effectors necessary for MAPK activation and characterize RIT1 association with plasma membrane lipids and interaction with RAF kinases. We identify critical residues present in the RIT1 hypervariable region that facilitate interaction with negatively charged membrane lipids and show that these are necessary for association with RAF kinases. Although mutant RIT1 binds to RAF kinases directly, it fails to activate RAF-MAPK signaling in the absence of classical Ras proteins. Consistent with aberrant RAF/MEK/ERK activation as a driver of disease, we show that MEK inhibition alleviates cardiac hypertrophy in a mouse model of RIT1-mutant Noonan syndrome. These data shed light on pathogenic RIT1 function and identify avenues for therapeutic intervention. One Sentence SummaryElectrostatic plasma membrane association facilitates RIT1-mediated Ras-dependent RAF kinase activation to promote pathogenic MAPK signaling.

biochemistry↗

bioRxiv2022

What is particular about microplastics? A meta-analysis of the toxicity of microplastics and suspended sediments

Microplastics (MP) are perceived as a threat to aquatic ecosystems but bear many similarities to suspended sediments which are often considered less harmful. It is, therefore pertinent to determine if and to what extent MPs are different from other particles occurring in aquatic ecosystems in terms of their adverse effects. We applied meta-regressions to hazard data extracted from the literature and harmonized the data to construct Species Sensitivity Distributions (SSDs) for both types of particles. The results demonstrate that the average toxicity of MPs is approximately one order of magnitude higher than that of suspended solids. However, the estimates were associated with large uncertainties and did not provide very strong evidence. In part, this is due to the general lack of comparable experimental studies and dose-dependent point estimates. We, therefore, argue that a precautionary approach should be used and MP in the 1-1000 {micro}m size range should be considered moderately more hazardous to aquatic organisms capable of ingesting such particles. Organisms inhabiting oligotrophic habitats like coral reefs and alpine lakes, with naturally low levels of non-food particles are likely more vulnerable, and it is reasonable to assume that MP pose a relatively higher risk to aquatic life in such habitats. SynopsisA meta-analysis indicates that microplastics are one order of magnitude more toxic than suspended sediments/solids, an estimate surrounded by considerable uncertainty. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=110 SRC="FIGDIR/small/514507v2_ufig1.gif" ALT="Figure 1"> View larger version (46K): org.highwire.dtl.DTLVardef@18826c5org.highwire.dtl.DTLVardef@1a98189org.highwire.dtl.DTLVardef@17762d7org.highwire.dtl.DTLVardef@fa4a6d_HPS_FORMAT_FIGEXP M_FIG C_FIG

ecology↗

bioRxiv2022

Taurine as a key intermediate for host-symbiont interaction in the tropical sponge Ianthella basta

Marine sponges are critical components of marine benthic fauna assemblages where their filter-feeding and reef-building capabilities provide bentho-pelagic coupling and crucial habitat. As potentially the oldest representation of a metazoan-microbe symbiosis, they also harbor dense, diverse, and species-specific communities of microbes, which are increasingly recognized for their contributions to dissolved organic matter (DOM) processing. Recent omics-based studies of marine sponge microbiomes have proposed numerous pathways of dissolved metabolite exchange between the host and symbionts within the context of the surrounding environment, but few studies have sought to experimentally interrogate these pathways. By using a combination of metaproteogenomics and laboratory incubations coupled with isotope-based functional assays, we showed that the dominant gammaproteobacterial symbiont Candidatus Taurinisymbion ianthellae residing in the marine sponge, Ianthella basta, expresses a pathway for the import and dissimilation of taurine, a ubiquitously occurring sulfonate metabolite in marine sponges. Candidatus Taurinisymbion ianthellae incorporates taurine-derived carbon and nitrogen while, at the same time, oxidizing the dissimilated sulfite into sulfate for export. Furthermore, we found that taurine-derived ammonia is exported by the symbiont for immediate oxidation by the dominant ammonia-oxidizing thaumarchaeal symbiont Candidatus Nitrosospongia ianthellae. Metaproteogenomic analyses also indicate that Candidatus Taurinisymbion ianthellae likely imports DMSP and possesses both pathways for DMSP demethylation and cleavage, enabling it to use this compound as a carbon and sulfur source for biomass, as well as for energy conservation. These results highlight the important role of biogenic sulfur compounds in the interplay between Ianthella basta and its microbial symbionts.

microbiology↗

bioRxiv2022

Conservation of spatiotemporal DNA replication origin and terminus segregation patterns in Sinorhizobium meliloti with re-engineered bi- and monopartite genomes

Multipartite bacterial genomes pose challenges for genome engineering and establishment of additional replicons. We simplified the tripartite genome structure (3.65 Mbp chromosome, 1.35 Mbp megaplasmid pSymA, 1.68 Mbp chromid pSymB) of Sinorhizobium meliloti. Strains with bi- and monopartite genome configurations were generated by targeted replicon fusions. Our design preserved key genomic features, such as replichore ratios, GC skew, and KOPS and coding sequence distribution. Under standard culture conditions, growth rates of these strains and the wild type were nearly comparable. Spatiotemporal replicon organization and segregation were maintained in the triple replicon fusion strain. Deletion of the replication initiator-encoding genes including the oriVs of pSymA and pSymB from this strain resulted in a monopartite genome with oriC as the sole origin of replication, a strongly unbalanced replichore ratio, slow growth and an aberrant cellular localization of oriC. Suppressor mutation R436H in the cell cycle histidine kinase CckA and a 3.2 Mbp inversion, both individually, largely restored growth. These strains will facilitate integration of secondary replicons in S. meliloti, and thus be useful for genome engineering applications, such as generating hybrid genomes. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=105 SRC="FIGDIR/small/493018v3_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@1d016caorg.highwire.dtl.DTLVardef@8856ddorg.highwire.dtl.DTLVardef@fee530org.highwire.dtl.DTLVardef@78d9cd_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2022

Effects of microplastics mixed with natural particles on Daphnia magna populations

The toxicity of microplastics on Daphnia magna as a key model for freshwater zooplankton is well described. While several studies predict population-level effects based on short-term, individual-level responses, only very few have validated these predictions experimentally. Thus, we exposed D. magna populations to irregular polystyrene microplastics and diatomite as natural particle (both [≤] 63 m) over 50 days. We used mixtures of both particle types at fixed particle concentrations (50,000 particles mL-1) and recorded the effects on overall population size and structure, the size of the individual animals, and resting egg production. Particle exposure adversely affected the population size and structure and induced resting egg production. The terminal population size was 28-42% lower in exposed compared to control populations. Interestingly, mixtures containing diatomite induced stronger effects than microplastics alone, highlighting that natural particles are not per se less toxic than microplastics. Our results demonstrate that an exposure to synthetic and natural particles has negative population-level effects on zooplankton. Understanding the mixture toxicity of microplastics and natural particles is important given that aquatic organisms will experience exposure to both. Just as for chemical pollutants, better knowledge of such joint effects is essential to fully understand the environmental impacts of complex particle mixtures. Environmental ImplicationsWhile microplastics are commonly considered hazardous based on individual-level effects, there is a dearth of information on how they affect populations. Since the latter is key for understanding the environmental impacts of microplastics, we investigated how particle exposures affect the population size and structure of Daphnia magna. In addition, we used mixtures of microplastics and natural particles because neither occurs alone in nature and joint effects can be expected in an environmentally realistic scenario. We show that such mixtures adversely affect daphnid populations and highlight that population-level and mixture-toxicity designs are one important step towards more environmental realism in microplastics research. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=118 SRC="FIGDIR/small/490562v3_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@11a9358org.highwire.dtl.DTLVardef@1bfa315org.highwire.dtl.DTLVardef@6bc0cdorg.highwire.dtl.DTLVardef@3ef1b8_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIDaphnia populations exposed to mixtures of microplastics and diatomite C_LIO_LIEffects on population size, structure, and resting egg production C_LIO_LIDiatomite as natural particle more toxic than microplastics C_LIO_LIParticle mixtures induce negative population-level effects C_LIO_LIParticle mixtures represent more realistic exposure scenario C_LI

ecology↗

bioRxiv2022

Optimal routing to cerebellum-like structures

The vast expansion from mossy fibers to cerebellar granule cells produces a neural representation that supports functions including associative and internal model learning. This motif is shared by other cerebellum-like structures, including the insect mushroom body, electrosensory lobe of electric fish, and mammalian dorsal cochlear nucleus, and has inspired numerous theoretical models of its functional role. Less attention has been paid to structures immediately presynaptic to granule cell layers, whose architecture can be described as a "bottleneck" and whose functional role is not understood. We therefore develop a general theory of cerebellum-like structures in conjunction with their afferent pathways. This theory predicts the role of the pontine relay to cerebellar cortex and the glomerular organization of the insect antennal lobe. It also reconciles theories of nonlinear mixing with recent observations of correlated granule cell activity. More generally, it shows that structured compression followed by random expansion is an efficient architecture for flexible computation.

neuroscience↗

bioRxiv2021

Lifelong musical activity is associated with multi-domain cognitive and brain benefits in older adults

1AO_SCPLOWBSTRACTC_SCPLOWRegular musical activity as a highly-stimulating lifestyle activity is proposed to be protective against age-related cognitive decline and Alzheimers disease (AD). This study investigated associations between lifelong regular musical instrument playing, late-life cognitive abilities and brain morphology in older adults. We show that musical activity over the life course is associated with better global cognition, working memory, executive functions, language, and visuospatial abilities accounting for reserve proxies. Playing music is not significantly associated with gray matter volume in regions most affected by aging and AD. Selectively in the musically active participants, multi-domain cognitive abilities were enhanced with preserved gray matter volume in frontal and temporal regions. Our correlational findings suggest that playing a musical instrument may improve the recruitment of existing brain resources to facilitate late-life cognitive capacities. We propose that engaging in regular musical activity could serve as a low-threshold multimodal enrichment strategy that may promote cognitive resilience in advanced age.

neuroscience↗

bioRxiv2021

Expression variations in Ectodysplasin-A gene (eda) may contribute to morphological divergence of scales in Haplochromine cichlids

BackgroundElasmoid scales are one of the most common dermal appendages and can be found in almost all species of bony fish differing greatly in their shape. Whilst the genetic underpinnings behind elasmoid scale development have been investigated, not much is known about the mechanisms involved in the shaping of scales. To investigate the links between gene expression differences and morphological divergence, we inferred shape variation of scales from two different areas of the body (anterior and posterior) stemming from ten haplochromine cichlid species from different origins (Lake Tanganyika, Lake Malawi, Lake Victoria and riverine). Additionally, we investigated transcriptional differences of a set of genes known to be involved in scale development and morphogenesis in fish. ResultsWe found that scales from the anterior and posterior part of the body strongly differ in their overall shape, and a separate look on scales from each body part revealed similar trajectories of shape differences considering the lake origin of single investigated species. Above all, nine as well as 11 out of 16 target genes showed expression differences between the lakes for the anterior and posterior dataset, respectively. Whereas in posterior scales four genes (dlx5, eda, rankl and shh) revealed significant correlations between expression and morphological differentiation, in anterior scales only one gene (eda) showed such a correlation. Furthermore, eda displayed the most significant expression difference between species of Lake Tanganyika and species of the other two younger lakes. Finally, we found genetic differences in downstream regions of eda gene (e.g. in the eda-tnfsf13b inter-genic region) that are associated with observed expression differences. This is reminiscent of a genetic difference in the eda-tnfsf13b inter-genic region which leads to gain or loss of armour plates in stickleback. ConclusionThese findings provide evidence for cross-species transcriptional differences of an important morphogenetic factor, eda, which is involved in formation of ectodermal appendages. These expression differences appeared to be associated with morphological differences observed in the scales of haplochromine cichlids indicating potential role of eda mediated signal in divergent scale morphogenesis in fish.

evolutionary biology↗

bioRxiv2021

Adipogenic activity of chemicals used in plastic consumer products

Bisphenols and phthalates, chemicals frequently used in plastic products, promote obesity in cell and animal models. However, these well-known metabolism disrupting chemicals (MDCs) represent only a minute fraction of all compounds found in plastics. To gain a comprehensive understanding of plastics as a source of exposure to MDCs, we characterized all chemicals present in 34 everyday products using nontarget high-resolution mass spectrometry and analyzed their joint adipogenic activities by high-content imaging. We detected 55,300 chemical features and tentatively identified 629 unique compounds, including 11 known MDCs. Importantly, chemicals that induced proliferation, growth, and triglyceride accumulation in 3T3-L1 adipocytes were found in one third of the products. Since the majority did not target peroxisome proliferator-activated receptor {gamma}, the effects are likely to be caused by unknown MDCs. Our study demonstrates that daily-use plastics contain potent mixtures of MDCs and can, therefore, be a relevant yet underestimated environmental factor contributing to obesity. TeaserPlastics contain a potent mixture of chemicals promoting adipogenesis, a key process in developing obesity.

pharmacology and toxicology↗

bioRxiv2021

SRS-FISH: High-Throughput Platform Linking Microbiome Function to Identity at the Single Cell Level

One of the biggest challenges in microbiome research in environmental and medical samples is to better understand functional properties of microbial community members at a single cell level. Single cell isotope probing has become a key tool for this purpose, but the currently applied detection methods for measuring isotope incorporation into single cells do not allow high-throughput analyses. Here, we report on the development of an imaging-based approach termed stimulated Raman scattering - two-photon fluorescence in situ hybridization (SRS-FISH) for high-throughput structure-function analyses of microbial communities with single cell resolution. SRS-FISH has an imaging speed of 10 to 100 milliseconds per cell, which is two to three orders of magnitude faster than spontaneous Raman-FISH. Using this technique, we delineated metabolic responses of thirty thousand individual cells to various mucosal sugars in the human gut microbiome via incorporation of deuterium from heavy water as an activity marker. Application of SRS-FISH to investigate the utilization of host-derived nutrients by two major human gut microbiome taxa revealed that response to mucosal sugars tends to be dominated by Bacteroidales, with an unexpected finding that Clostridia can outperform Bacteroidales at foraging fucose.

microbiology↗

bioRxiv2021

The diversity of quinoa morphological traits and seed metabolic composition

Quinoa (Chenopodium quinoa Willd.) is an herbaceous annual crop of the amaranth family (Amaranthaceae). It is increasingly cultivated for its nutritious grains, which are rich in protein and essential amino acids, lipids, and minerals. Quinoa exhibits a high tolerance towards various abiotic stresses including drought and salinity, which supports its agricultural cultivation under climate change conditions. The use of quinoa grains is compromised by anti-nutritional saponins, a terpenoid class of secondary metabolites deposited in the seed coat; their removal before consumption requires extensive washing, an economically and environmentally unfavorable process; or their accumulation can be reduced through breeding. In this study, we analyzed the seed metabolomes, including amino acids, fatty acids, and saponins, from 471 quinoa cultivars, including two related species, by liquid chromatography - mass spectrometry. Additionally, we determined a large number of agronomic traits including biomass, flowering time, and seed yield. The results revealed considerable diversity between genotypes and provide a knowledge base for future breeding or genome editing of quinoa. O_TBL View this table: org.highwire.dtl.DTLVardef@160e784org.highwire.dtl.DTLVardef@ff8bd1org.highwire.dtl.DTLVardef@13446daorg.highwire.dtl.DTLVardef@11796eeorg.highwire.dtl.DTLVardef@1b607b8_HPS_FORMAT_FIGEXP M_TBL C_TBL

plant biology↗

bioRxiv2021

Synthesis and Structure Elucidation of the Human tRNA Nucleoside Mannosyl-Queuosine

Queuosine (Q) is a structurally complex, non-canonical RNA nucleoside. It is present in many eukaryotic and bacterial species, where it is part of the anticodon loop of certain tRNAs. In higher vertebrates, including humans, two further modified queuosine-derivatives exist - galactosyl-(galQ) and mannosyl-queuosine (manQ). The function of these low abundant hypermodified RNA nucleosides remains unknown. While the structure of galQ was elucidated and confirmed by total synthesis, the reported structure of manQ still awaits confirmation. By combining total synthesis and LC-MS-co-injection, together with a metabolic feeding study of labelled hexoses, we show here that the natural compound manQ isolated from mouse liver deviates from the literature-reported structure. The chemical structure of the natural product manQ features a novel -allyl connectivity. The data reported here shows that the yet unidentified glycosylases that attach galactose and mannose to the Q-base have different constitutional connectivity preferences. Knowing the correct structure of manQ will now pave the way towards further elucidation of its biological function.

biochemistry↗

bioRxiv2021

How do symbiotic associations in lecideoid lichens respond to different environmental conditions along the Transantarctic Mountains, Ross Sea region, Antarctica?

Lecideoid lichens as dominant vegetation-forming organisms in the climatically harsh areas of the southern part of continental Antarctica show clear preferences in relation to environmental conditions (i.e. macroclimate). 306 lichen samples were included in the study, collected along the Ross Sea coast (78{degrees}S-85.5{degrees}S) at six climatically different sites. The species compositions as well as the associations of their two dominant symbiotic partners (myco- and photobiont) were set in context with environmental conditions along the latitudinal gradient. Diversity values were nonlinear with respect to latitude, with the highest alpha diversity in the milder areas of the McMurdo Dry Valleys (78{degrees}S) and the most southern areas (Durham Point, 85.5{degrees}S; Garden Spur, 84.5{degrees}S), and lowest in the especially arid and cold Darwin Area (~79.8{degrees}S). Furthermore, the specificity of mycobiont species towards their photobionts decreased under more severe climate conditions. The generalist lichen species Lecanora fuscobrunnea and Lecidea cancriformis were present in almost all habitats, but were dominant in climatically extreme areas. Carbonea vorticosa, Lecidella greenii and Rhizoplaca macleanii were confined to milder areas. In summary, the macroclimate is considered to be the main driver of species distribution, making certain species useful as bioindicators of climate conditions and, consequently, for detecting climate change.

ecology↗