Diversität und Dynamik denitrifizierender und nitratreduzierender Bakteriengruppen eines Ackerbodens

In der vorliegenden Arbeit wurden klassische mikrobiologische Methoden (Kultivierung, Denitrifikationstests) und molekularbiologische Methoden (PCR von 16S rDNA-Fragmenten und Auftrennung der Amplifikate mittels Denaturierenden Gradienten Gel Elektrophorese (DGGE)) angewandt, die es erlauben die Diversität der ökologisch bedeutenden physiologischen Bakteriengruppe der Denitrifikanten bzw. Niratreduzierer in unterschiedlich gedüngten Parzellen eines Ackerbodens im Jahresgang zu analysieren. Durch die Isolierung wesentlicher Mitglieder dieser Bakteriengruppe und ihre Identifizierung über Fettsäuremuster wurde ein Überblick über die am Standort vorhandenen und mit den eingesetzten Verfahren kultivierbaren Bakterien, die zum dissimilatorischen Umsatz von Nitrat in der Lage sind, geschaffen. Gleichzeitig wurde eine Dynamik wesentlicher Mitglieder der Bakteriengemein-schaft im Jahresgang mit Hilfe der DGGE untersucht. Die isolierten Stämme dienten außerdem als Referenz für die Untersuchungen aus der Standort-DNA. Von Interesse war insbesondere die Diversität der Pseudomonaden, Bacilli und Bakterien der Gruppe Cytophaga/Flavobacterium, um mögliche Einflüsse ackerbaulicher Maßnahmen auf die Diversität einzelner Bakteriengruppen nachzuweisen. Die Auswertung der mittels PCR/DGGE erhaltenen Ergebnisse ergab eine eindeutige Änderung der Diversität von Bakterien der Gruppen Cytophaga/Flavobacterium mit Wechsel der angebauten Feldfrucht. Innerhalb eines Jahresganges konnten keine Diversitätsschwankungen festgestellt werden. Auch stimmten die Diversitätsmuster dieser Bakteriengruppe aller unterschiedlich behandelten Ackerparzellen fast vollständig überein

Diversität und Dynamik nitratreduzierender und denitrifizierender Bakteriengruppen eines Ackerbodens

In der vorliegenden Arbeit wurden klassische mikrobiologische Methoden (Kultivierung, Denitrifikationstests) und molekularbiologische Methoden (PCR von 16S rDNA-Fragmenten und Auftrennung der Amplifikate mittels Denaturierenden Gradienten Gel Elektrophorese (DGGE)) angewandt, die es erlauben die Diversität der ökologisch bedeutenden physiologischen Bakteriengruppe der Denitrifikanten bzw. Niratreduzierer in unterschiedlich gedüngten Parzellen eines Ackerbodens im Jahresgang zu analysieren. Durch die Isolierung wesentlicher Mitglieder dieser Bakteriengruppe und ihre Identifizierung über Fettsäuremuster wurde ein Überblick über die am Standort vorhandenen und mit den eingesetzten Verfahren kultivierbaren Bakterien, die zum dissimilatorischen Umsatz von Nitrat in der Lage sind, geschaffen. Gleichzeitig wurde eine Dynamik wesentlicher Mitglieder der Bakteriengemein-schaft im Jahresgang mit Hilfe der DGGE untersucht. Die isolierten Stämme dienten außerdem als Referenz für die Untersuchungen aus der Standort-DNA. Von Interesse war insbesondere die Diversität der Pseudomonaden, Bacilli und Bakterien der Gruppe Cytophaga/Flavobacterium, um mögliche Einflüsse ackerbaulicher Maßnahmen auf die Diversität einzelner Bakteriengruppen nachzuweisen. Die Auswertung der mittels PCR/DGGE erhaltenen Ergebnisse ergab eine eindeutige Änderung der Diversität von Bakterien der Gruppen Cytophaga/Flavobacterium mit Wechsel der angebauten Feldfrucht. Innerhalb eines Jahresganges konnten keine Diversitätsschwankungen festgestellt werden. Auch stimmten die Diversitätsmuster dieser Bakteriengruppe aller unterschiedlich behandelten Ackerparzellen fast vollständig überein

Eemian landscape response to climatic shifts and evidence for northerly neanderthal occupation at a palaeolake margin in northern germany

The prevailing view suggests that the Eemian interglacial on the European Plain was characterized by largely negligible geomorphic activity beyond the coastal areas. However, systematic geomorphological studies are sparse. Here we present a detailed reconstruction of Eemian to Early Weichselian landscape evolution in the vicinity of a small fingerlake on the northern margin of the Salzwedel Palaeolake in Lower Saxony (Germany). We apply a combination of seismics, sediment coring, pollen analysis and luminescence dating on a complex sequence of colluvial, paludal and lacustrine sediments. Results suggest two pronounced phases of geomorphic activity, directly before the onset and at the end of the Eemian period, with an intermediate period of pronounced landscape stability. The dynamic phases were largely driven by incomplete vegetation cover, but likely accentuated by fluvial incision in the neighbouring Elbe Valley. Furthermore, we discovered Neanderthal occupation at the lakeshore during Eemian pollen zone (PZ) E IV, which is chronologically in line with other known Eemian sites of central Europe. Our highly‐resolved spatio‐temporal data substantially contribute to the understanding of climate‐induced geomorphic processes throughout and directly after the last interglacial period. It helps unraveling the landscape dynamics between the coastal areas to the north and the loess belt to the south

Eemian landscape response to climatic shifts and evidence for northerly Neanderthal occupation at a palaeolake margin in northern Germany

The prevailing view suggests that the Eemian interglacial on the European Plain was characterized by largely negligible geomorphic activity beyond the coastal areas. However, systematic geomorphological studies are sparse. Here we present a detailed reconstruction of Eemian to Early Weichselian landscape evolution in the vicinity of a small fingerlake on the northern margin of the Salzwedel Palaeolake in Lower Saxony (Germany). We apply a combination of seismics, sediment coring, pollen analysis and luminescence dating on a complex sequence of colluvial, paludal and lacustrine sediments. Results suggest two pronounced phases of geomorphic activity, directly before the onset and at the end of the Eemian period, with an intermediate period of pronounced landscape stability. The dynamic phases were largely driven by incomplete vegetation cover, but likely accentuated by fluvial incision in the neighbouring Elbe Valley. Furthermore, we discovered Neanderthal occupation at the lakeshore during Eemian pollen zone (PZ) E IV, which is chronologically in line with other known Eemian sites of central Europe. Our highly-resolved spatio-temporal data substantially contribute to the understanding of climate-induced geomorphic processes throughout and directly after the last interglacial period. It helps unraveling the landscape dynamics between the coastal areas to the north and the loess belt to the south

Different neuroinflammatory profile in amyotrophic lateral sclerosis and frontotemporal dementia is linked to the clinical phase

Objective To investigate the role of neuroinflammation in asymptomatic and symptomatic amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) mutation carriers. Methods The neuroinflammatory markers chitotriosidase 1 (CHIT1), YKL-40 and glial fibrillary acidic protein (GFAP) were measured in cerebrospinal fluid (CSF) and blood samples from asymptomatic and symptomatic ALS/FTD mutation carriers, sporadic cases and controls by ELISA. Results CSF levels of CHIT1, YKL-40 and GFAP were unaffected in asymptomatic mutation carriers (n=16). CHIT1 and YKL-40 were increased in gALS (p<0.001, n=65) whereas GFAP was not affected. Patients with ALS carrying a CHIT1 polymorphism had lower CHIT1 concentrations in CSF (-80%) whereas this polymorphism had no influence on disease severity. In gFTD (n=23), increased YKL-40 and GFAP were observed (p<0.05), whereas CHIT1 was nearly not affected. The same profile as in gALS and gFTD was observed in sALS (n=64/70) and sFTD (n=20/26). CSF and blood concentrations correlated moderately (CHIT1, r=0.51) to weak (YKL-40, r=0.30, GFAP, r=0.39). Blood concentrations of these three markers were not significantly altered in any of the groups except CHIT1 in gALS of the Ulm cohort (p<0.05). Conclusion Our data indicate that neuroinflammation is linked to the symptomatic phase of ALS/FTD and shows a similar pattern in sporadic and genetic cases. ALS and FTD are characterised by a different neuroinflammatory profile, which might be one driver of the diverse presentations of the ALS/FTD syndrome

Antifungal isolates database of amphibian skin-associated bacteria and function against emerging fungal pathogens

Microbial symbionts of vertebrate skin have an important function in defense of the host against pathogens. In particular, the emerging chytrid fungus Batrachochytrium dendrobatidis, causes widespread disease in amphibians but can be inhibited via secondary metabolites produced by many different skin-associated bacteria. Similarly, the fungal pathogens of terrestrial salamander eggs Mariannaea elegans and Rhizomucor variabilis are also inhibited by a variety of skin-associated bacteria. Indeed, probiotic therapy against fungal diseases is a recent approach in conservation medicine with growing experimental support. We present a comprehensive Antifungal Isolates Database of amphibian skin-associated bacteria that have been cultured, isolated, and tested for antifungal properties. At the start, this database includes nearly 2000 cultured bacterial isolates from 37 amphibian host species across 18 studies on five continents: Africa, Oceania, Europe, and North and South America. As the research community gathers information on additional isolates, the database will be updated periodically. The resulting database can serve as a conservation tool for amphibians and other organisms, and provides empirical data for comparative and bioinformatic studies. The database consists of a FASTA file containing 16S rRNA gene sequences of the bacterial isolates, and a metadata file containing information on the host species, life-stage, geographic region, and antifungal capacity and taxonomic identity of the isolate

Phylogenetic Characterization of Marine Benthic Archaea in Organic-Poor Sediments of the Eastern Equatorial Pacific Ocean (ODP Site 1225)

Sequencing surveys of microbial communities in marine subsurface sediments have focused on organic-rich, continental margins; the database for organic-lean deep-sea sediments from mid-ocean regions is underdeveloped. The archaeal community in subsurface sediments of ODP Site 1225 in the eastern equatorial Pacific (3760 m water depth; 1.1 and 7.8 m sediment depth) was analyzed by PCR, cloning and sequencing, and by denaturant gradient gel electrophoresis (DGGE) of 16S rRNA genes. Three uncultured archaeal lineages with different depth distributions were found: Marine Group I (MG-I) within the Thaumarchaeota, its sister lineage Marine Benthic Group A (MBG-A), the phylum-level archaeal lineage Marine Benthic Group B (also known as Deep-Sea Archaeal Group or Lokiarchaeota), and the Deep-Sea Euryarchaeotal Group 3. The MG-I phylotypes included representatives of sediment clusters that are distinct from the pelagic members of this phylum. On the scale from fully oxidized, extremely organic carbon-depleted sediments (for example, those the South Pacific Gyre) to fully reduced, organic carbon-rich marine subsurface sediments (such as those of the Peru Margin), Ocean Drilling Program (ODP) Site 1225 falls into the non-extreme organic carbon-lean category, and harbors archaeal communities from both ends of the spectrum

Risk of Exposure to Coccidioides spp. in the Temblor Special Recreation Management Area (SRMA), Kern County, CA

The Temblor Mountain Special Recreation Area (SRMA) on the western flank of the San Joaquin Valley, CA, is located in the endemic area of Coccidioides, a fungal pathogen responsible for the increasing incidence of coccidioidomycosis (Valley fever). Recreationists in the SRMA, such as off-highway vehicle (OHV) drivers and mountain bikers who disturb the soils, are at risk of being exposed to airborne arthroconidia (asexual spores) of the pathogen. To reduce the risk of pathogen exposure for visitors, the Bureau of Land Management (BLM) plans to limit recreational activities to areas with a reduced pathogen presence. They envision an official OHV park in the future, by also restricting access to areas with ongoing restoration efforts and by limiting soil erosion in sensitive areas. To investigate which soils in the Temblor SRMA are most likely to support the growth of Coccidioides spp., soil samples were collected over a 3-year period from dominant soil types in a northern and a southern sampling area and analyzed for the pathogen using a culture-independent PCR-based method. In addition, soil pH and electrical conductivity were determined. The results of this study revealed slight genetic variance in the Coccidioides sequences obtained from the soils of the Temblor SRMA. An analysis of variance (ANOVA) could not confirm differences in soil pH and electrical conductivity (EC) between the different soil types investigated and between sites where the pathogen was detected compared to sites where it could not be found. However, the year of sampling appeared to have an influence on observed soil pH and EC, and the presence of the pathogen. Of all dominant soil types investigated, those belonging to the Littlesignal&ndash;Cochora association were the least likely to contain the pathogen, whereas soils of the Beam&ndash;Panoza&ndash;Hillbrick association appeared more supportive. In addition to pointing out OHV areas with lower pathogen exposure risk in the Temblor SRMA, recommendations were made to educate visitors and BLM workers about the risk of contracting Valley fever

Phylogenetic Characterization of Marine Benthic Archaea in Organic-Poor Sediments of the Eastern Equatorial Pacific Ocean (ODP Site 1225)

Sequencing surveys of microbial communities in marine subsurface sediments have focused on organic-rich, continental margins; the database for organic-lean deep-sea sediments from mid-ocean regions is underdeveloped. The archaeal community in subsurface sediments of ODP Site 1225 in the eastern equatorial Pacific (3760 m water depth; 1.1 and 7.8 m sediment depth) was analyzed by PCR, cloning and sequencing, and by denaturant gradient gel electrophoresis (DGGE) of 16S rRNA genes. Three uncultured archaeal lineages with different depth distributions were found: Marine Group I (MG-I) within the Thaumarchaeota, its sister lineage Marine Benthic Group A (MBG-A), the phylum-level archaeal lineage Marine Benthic Group B (also known as Deep-Sea Archaeal Group or Lokiarchaeota), and the Deep-Sea Euryarchaeotal Group 3. The MG-I phylotypes included representatives of sediment clusters that are distinct from the pelagic members of this phylum. On the scale from fully oxidized, extremely organic carbon-depleted sediments (for example, those the South Pacific Gyre) to fully reduced, organic carbon-rich marine subsurface sediments (such as those of the Peru Margin), Ocean Drilling Program (ODP) Site 1225 falls into the non-extreme organic carbon-lean category, and harbors archaeal communities from both ends of the spectrum

Risk of Exposure to <i>Coccidioides</i> spp. in the Temblor Special Recreation Management Area (SRMA), Kern County, CA

The Temblor Mountain Special Recreation Area (SRMA) on the western flank of the San Joaquin Valley, CA, is located in the endemic area of Coccidioides, a fungal pathogen responsible for the increasing incidence of coccidioidomycosis (Valley fever). Recreationists in the SRMA, such as off-highway vehicle (OHV) drivers and mountain bikers who disturb the soils, are at risk of being exposed to airborne arthroconidia (asexual spores) of the pathogen. To reduce the risk of pathogen exposure for visitors, the Bureau of Land Management (BLM) plans to limit recreational activities to areas with a reduced pathogen presence. They envision an official OHV park in the future, by also restricting access to areas with ongoing restoration efforts and by limiting soil erosion in sensitive areas. To investigate which soils in the Temblor SRMA are most likely to support the growth of Coccidioides spp., soil samples were collected over a 3-year period from dominant soil types in a northern and a southern sampling area and analyzed for the pathogen using a culture-independent PCR-based method. In addition, soil pH and electrical conductivity were determined. The results of this study revealed slight genetic variance in the Coccidioides sequences obtained from the soils of the Temblor SRMA. An analysis of variance (ANOVA) could not confirm differences in soil pH and electrical conductivity (EC) between the different soil types investigated and between sites where the pathogen was detected compared to sites where it could not be found. However, the year of sampling appeared to have an influence on observed soil pH and EC, and the presence of the pathogen. Of all dominant soil types investigated, those belonging to the Littlesignal–Cochora association were the least likely to contain the pathogen, whereas soils of the Beam–Panoza–Hillbrick association appeared more supportive. In addition to pointing out OHV areas with lower pathogen exposure risk in the Temblor SRMA, recommendations were made to educate visitors and BLM workers about the risk of contracting Valley fever