Analysis of surface structures and thermal distribution of Grenzgletscher ablation area with multispectral and thermal imagery

Due to climate change, glaciers and ice sheets are increasingly melting. Many glaciers in polar and subpolar regions as well the Greenland and Antarctic ice sheet are polythermal. Which arises questions about how a polythermal glacier reacts, when a shift from a polythermal regime to a temperate regime occurs. The largest polythermal glacier in the Alps is the Grenzgletscher, where the ablation zone shows typical surface structures for cold ice. This makes the Grenzgletscher a perfect study site to study a polythermal glacier under warming conditions and then extrapolate the findings to the arctic and subarctic region. The analysis of surface structures and thermal distribution at different locations on in the ablation zone of Grenzgletscher can be interpreted as studies under different climate conditions. By using multispectral and thermal imagery this thesis analyzed the surface of the ablation zone and tries to correlate the findings with the ice temperature. This analysis are important in understanding how a polythermal glacier adapts to warmer climate and what has to be considered in glaciological models

Metagenome sequencing of the microbial community of a solar saltern crystallizer pond at cáhuil lagoon, chile.

Cáhuil Lagoon in central Chile harbors distinct microbial communities in various solar salterns that are arranged as interconnected ponds with increasing salt concentrations. Here, we report the metagenome of the 3.0- to 0.2-µm fraction of the microbial community present in a crystallizer pond with 34% salinity

Distinctive Archaeal Composition of an Artisanal Crystallizer Pond and Functional Insights Into Salt-Saturated Hypersaline Environment Adaptation

Hypersaline environments represent some of the most challenging settings for life on Earth. Extremely halophilic microorganisms have been selected to colonize and thrive in these extreme environments by virtue of a broad spectrum of adaptations to counter high salinity and osmotic stress. Although there is substantial data on microbial taxonomic diversity in these challenging ecosystems and their primary osmoadaptation mechanisms, less is known about how hypersaline environments shape the genomes of microbial inhabitants at the functional level. In this study, we analyzed the microbial communities in five ponds along the discontinuous salinity gradient from brackish to salt-saturated environments and sequenced the metagenome of the salt (halite) precipitation pond in the artisanal Cáhuil Solar Saltern system. We combined field measurements with spectrophotometric pigment analysis and flow cytometry to characterize the microbial ecology of the pond ecosystems, including primary producers and applied metagenomic sequencing for analysis of archaeal and bacterial taxonomic diversity of the salt crystallizer harvest pond. Comparative metagenomic analysis of the Cáhuil salt crystallizer pond against microbial communities from other salt-saturated aquatic environments revealed a dominance of the archaeal genus Halorubrum and showed an unexpectedly low abundance of Haloquadratum in the Cáhuil system. Functional comparison of 26 hypersaline microbial metagenomes revealed a high proportion of sequences associated with nucleotide excision repair, helicases, replication and restriction-methylation systems in all of them. Moreover, we found distinctive functional signatures between the microbial communities from salt-saturated (>30% [w/v] total salinity) compared to sub-saturated hypersaline environments mainly due to a higher representation of sequences related to replication, recombination and DNA repair in the former. The current study expands our understanding of the diversity and distribution of halophilic microbial populations inhabiting salt-saturated habitats and the functional attributes that sustain them

Applying UAV-Based Remote Sensing Observation Products in High Arctic Catchments in SW Spitsbergen

In the age of remote sensing, particularly with new generation Uncrewed Aerial Vehicles (UAVs), there is a broad spectrum of applications, especially in remote and rapidly changing areas such as the Arctic. Due to challenging conditions in this region, there is a scarcity of detailed spatial studies with data that may be used to estimate changes in glacier volume and geomorphological changes caused by permafrost freeze–thaw cycles. Drone-based Digital Elevation Models (DEM) offer a finer spatial resolution with higher accuracy than airborne and satellite-based products that can be used for acquiring, interpreting, and precisely representing spatial data in broad studies. In this study, we evaluate a UAV-based DEM of two High Arctic catchments, Fuglebekken and Ariebekken, located on Spitsbergen Island. The surveys were carried out in July 2022 using a DJI Matrice 300 RTK drone equipped with a photogrammetric Zenmuse P1 camera. A total of 371 images were taken, covering an area of 7.81 km2. The DEM was created by the Structure-from-Motion technique and achieved a centimetre-level accuracy by overlapping very high-resolution images. The final resolution of the DEM was found to be 0.06 m in Fuglebekken and 0.07 m in Ariebekken, with a horizontal and vertical RMSE of 0.09 m and 0.20 m, respectively. The DJI Matrice 300 RTK drone-based DEM is compared and correlated with the aerial mission of the Svalbard Integrated Arctic Earth Observing System (SIOS) conducted in July 2020 and the satellite-based ArcticDEM acquired in July 2018. This allowed the detection of elevation changes and identification of landscape evolution, such as moraine breaches and coastal erosion. We also highlight the usage of DEM in providing detailed morphometric characteristics and hydrological parameters, such as the delineation of catchments and stream channels. The final products are available at the IG PAS Data Portal

Applying UAV-Based Remote Sensing Observation Products in High Arctic Catchments in SW Spitsbergen

In the age of remote sensing, particularly with new generation Uncrewed Aerial Vehicles (UAVs), there is a broad spectrum of applications, especially in remote and rapidly changing areas such as the Arctic. Due to challenging conditions in this region, there is a scarcity of detailed spatial studies with data that may be used to estimate changes in glacier volume and geomorphological changes caused by permafrost freeze–thaw cycles. Drone-based Digital Elevation Models (DEM) offer a finer spatial resolution with higher accuracy than airborne and satellite-based products that can be used for acquiring, interpreting, and precisely representing spatial data in broad studies. In this study, we evaluate a UAV-based DEM of two High Arctic catchments, Fuglebekken and Ariebekken, located on Spitsbergen Island. The surveys were carried out in July 2022 using a DJI Matrice 300 RTK drone equipped with a photogrammetric Zenmuse P1 camera. A total of 371 images were taken, covering an area of 7.81 km2. The DEM was created by the Structure-from-Motion technique and achieved a centimetre-level accuracy by overlapping very high-resolution images. The final resolution of the DEM was found to be 0.06 m in Fuglebekken and 0.07 m in Ariebekken, with a horizontal and vertical RMSE of 0.09 m and 0.20 m, respectively. The DJI Matrice 300 RTK drone-based DEM is compared and correlated with the aerial mission of the Svalbard Integrated Arctic Earth Observing System (SIOS) conducted in July 2020 and the satellite-based ArcticDEM acquired in July 2018. This allowed the detection of elevation changes and identification of landscape evolution, such as moraine breaches and coastal erosion. We also highlight the usage of DEM in providing detailed morphometric characteristics and hydrological parameters, such as the delineation of catchments and stream channels. The final products are available at the IG PAS Data Portal

MGMT-Methylation in Non-Neoplastic Diseases of the Central Nervous System

Quantifying O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation plays an essential role in assessing the potential efficacy of alkylating agents in the chemotherapy of malignant gliomas. MGMT promoter methylation is considered to be a characteristic of subgroups of certain malignancies but has also been described in various peripheral inflammatory diseases. However, MGMT promoter methylation levels have not yet been investigated in non-neoplastic brain diseases. This study demonstrates for the first time that one can indeed detect slightly enhanced MGMT promoter methylation in individual cases of inflammatory demyelinating CNS diseases such as multiple sclerosis and progressive multifocal leucencephalopathy (PML), as well as in other demyelinating diseases such as central pontine and exptrapontine myelinolysis, and diseases with myelin damage such as Wallerian degeneration. In this context, we identified a reduction in the expression of the demethylase TET1 as a possible cause for the enhanced MGMT promoter methylation. Hence, we show for the first time that MGMT hypermethylation occurs in chronic diseases that are not strictly associated to distinct pathogens, oncogenic viruses or neoplasms but that lead to damage of the myelin sheath in various ways. While this gives new insights into epigenetic and pathophysiological processes involved in de- and remyelination, which might offer new therapeutic opportunities for demyelinating diseases in the future, it also reduces the specificity of MGMT hypermethylation as a tumor biomarker

Myelination in Multiple Sclerosis Lesions Is Associated with Regulation of Bone Morphogenetic Protein 4 and Its Antagonist Noggin

Remyelination is a central aspect of new multiple sclerosis (MS) therapies, in which one aims to alleviate disease symptoms by improving axonal protection. However, a central problem is mediators expressed in MS lesions that prevent effective remyelination. Bone morphogenetic protein4 (BMP4) inhibits the development of mature oligodendrocytes in cell culture and also blocks the expression of myelin proteins. Additionally, numerous studies have shown that Noggin (SYM1)—among other physiological antagonists of BMP4—plays a prominent role in myelin formation in the developing but also the adult central nervous system. Nonetheless, neither BMP4 nor Noggin have been systematically studied in human MS lesions. In this study, we demonstrated by transcript analysis and immunohistochemistry that BMP4 is expressed by astrocytes and microglia/macrophages in association with inflammatory infiltrates in MS lesions, and that astrocytes also express BMP4 in chronic inactive lesions that failed to remyelinate. Furthermore, the demonstration of an increased expression of Noggin in so-called shadow plaques (i.e., remyelinated lesions with thinner myelin sheaths) in comparison to chronically inactive demyelinated lesions implies that antagonizing BMP4 is associated with successful remyelination in MS plaques in humans. However, although BMP4 is strongly overexpressed in inflammatory lesion areas, its levels are also elevated in remyelinated lesion areas, which raises the possibility that BMP4 signaling itself may be required for remyelination. Therefore, remyelination might be influenced by a small number of key factors. Manipulating these molecules, i.e., BMP4 and Noggin, could be a promising therapeutic approach for effective remyelination

Two flagellar BAR domain proteins in Trypanosoma brucei with stage-specific regulation

Trypanosomes are masters of adaptation to different host environments during their complex life cycle. Large-scale proteomic approaches provide information on changes at the cellular level, and in a systematic way. However, detailed work on single components is necessary to understand the adaptation mechanisms on a molecular level. Here, we have performed a detailed characterization of a bloodstream form (BSF) stage-specific putative flagellar host adaptation factor Tb927.11.2400, identified previously in a SILAC-based comparative proteome study. Tb927.11.2400 shares 38% amino acid identity with TbFlabarin (Tb927.11.2410), a procyclic form (PCF) stage-specific flagellar BAR domain protein. We named Tb927.11.2400 TbFlabarin-like (TbFlabarinL), and demonstrate that it originates from a gene duplication event, which occurred in the African trypanosomes. TbFlabarinL is not essential for the growth of the parasites under cell culture conditions and it is dispensable for developmental differentiation from BSF to the PCF in vitro. We generated TbFlabarinL-specific antibodies, and showed that it localizes in the flagellum. Co-immunoprecipitation experiments together with a biochemical cell fractionation suggest a dual association of TbFlabarinL with the flagellar membrane and the components of the paraflagellar rod

Distinctive Archaeal Composition of an Artisanal Crystallizer Pond and Functional Insights Into Salt-Saturated Hypersaline Environment Adaptation.

Hypersaline environments represent some of the most challenging settings for life on Earth. Extremely halophilic microorganisms have been selected to colonize and thrive in these extreme environments by virtue of a broad spectrum of adaptations to counter high salinity and osmotic stress. Although there is substantial data on microbial taxonomic diversity in these challenging ecosystems and their primary osmoadaptation mechanisms, less is known about how hypersaline environments shape the genomes of microbial inhabitants at the functional level. In this study, we analyzed the microbial communities in five ponds along the discontinuous salinity gradient from brackish to salt-saturated environments and sequenced the metagenome of the salt (halite) precipitation pond in the artisanal Cáhuil Solar Saltern system. We combined field measurements with spectrophotometric pigment analysis and flow cytometry to characterize the microbial ecology of the pond ecosystems, including primary producers and applied metagenomic sequencing for analysis of archaeal and bacterial taxonomic diversity of the salt crystallizer harvest pond. Comparative metagenomic analysis of the Cáhuil salt crystallizer pond against microbial communities from other salt-saturated aquatic environments revealed a dominance of the archaeal genus Halorubrum and showed an unexpectedly low abundance of Haloquadratum in the Cáhuil system. Functional comparison of 26 hypersaline microbial metagenomes revealed a high proportion of sequences associated with nucleotide excision repair, helicases, replication and restriction-methylation systems in all of them. Moreover, we found distinctive functional signatures between the microbial communities from salt-saturated (>30% [w/v] total salinity) compared to sub-saturated hypersaline environments mainly due to a higher representation of sequences related to replication, recombination and DNA repair in the former. The current study expands our understanding of the diversity and distribution of halophilic microbial populations inhabiting salt-saturated habitats and the functional attributes that sustain them

Metagenome sequencing of the microbial community of a solar saltern crystallizer pond at cáhuil lagoon, chile.

Cáhuil Lagoon in central Chile harbors distinct microbial communities in various solar salterns that are arranged as interconnected ponds with increasing salt concentrations. Here, we report the metagenome of the 3.0- to 0.2-µm fraction of the microbial community present in a crystallizer pond with 34% salinity