The role of plants on methane flux out of upland soils

Soils play an important role in cycling of methane (CH4), a greenhouse gas contributing roughly 20% to the observed climate warming. While knowledge about the influence of plants on methane cycling is growing for wetland ecosystems, we are still limited in our understanding for upland soils. Thus, the objectives of this study were to investigate the influence of plants on net CH4 fluxes from forest and grassland soils depending on bedrock, temperature, and plant species, and to determine if changes in CH4 fluxes are reflected on microbial level. The present study used soils from forest and grassland sites located in Tyrol, Austria. Soil sites were chosen to represent soils from limestone and siliceous bedrock. To study grassland soils, two site-specific plants, Plantago lanceolata and Poa pratensis, were grown from seeds in pots. In case of forest soils, two site-specific trees, Picea abies and Larix decidua, were chosen and grown from seedlings. Besides profound soil microbiological analyses, lab-scale gas measurements were conducted at different temperatures. To characterize the microbial community structure of bulk and rhizosphere soil, NGS (next-generation sequencing) was performed. Further microbiological and molecular analyses aimed to determine if changes in CH4 fluxes are reflected in the activity and abundance of microorganisms in rhizosphere soil compared with bulk soil. Results showed that forest and grassland soils had a high potential to consume methane under ambient conditions, thus serving as methane sinks. Distinct differences depending on bedrock, plant species, and temperature were established. The studied site-specific grassland plants P. lanceolata and P. pratensis significantly increased methane balances to a varying extent depending on temperature. In contrast, the studied forest plants P. abies and especially L. decidua significantly boosted methane consumption. Further studies have focused on the influence of photosynthetic rates of plants on CH4 fluxes out of soils and the indirect influence of plants on soil microorganisms engaged in the methane cycle

Bodenmikrobiologie im Hochgebirge - zentrale Einflussfaktoren vor dem Hintergrund des Climate Change

Die Bodenmikrobiologie bekommt vor dem Hintergrund des climate change eine zusätzliche Bedeutung, da Mikroorganismen anders als alle andere Lebewesen nicht nur von gesteigerten Temperaturen beeinflusst werden, sondern auch aktiv – u.z. positiv wie negativ – in das Klimageschehen eingreifen können. Böden im Hochgebirge sind diesbezüglich und per se noch viel zu wenig erforscht und können darüber hinaus vor dem Hintergrund des Klimawandels als sehr gute Modelle für boreale und polare Regionen dienen, da Änderungen, die mit einer steigenden Seehöhe von 100 m im Gebirge einhergehen und somit den Änderungen in einem S-N-Transekt von ca. 400 km entsprechen, für riesige Gebiete relevant sind. Im internationalen GLORIA-Projekte werden weltweit 116 Standorte in 6 Kontinenten hinsichtlich der Auswirkungen des globalen Klimawandels auf vegetationskundliche Parameter untersucht. Im Rahmen des vorliegenden Projektes konnte erstmals einer der untersuchten master-sites des GLORIA-Forschungsprogramms, der Schrankogel mineralogisch, bodenchemisch und mikrobiologisch umfassend untersucht und die erhaltenen Daten mit abiotischen Standortfaktoren (Temperatur etc.) sowie botanischen Daten in Zusammenhang gebracht werden. Der Schrankogel befindet sich in den Ötztaler Alpen (Tirol/Österreich), ist 3.497 m hoch, verfügt über eine hinsichtlich der Steigung und der Geologie sehr konstante, fast über 1000 Höhenmeter reichende SW-Flanke und war somit für die geplanten Untersuchungen bestens geeignet. Anders als viele vergleichbare Studien, konnten sehr deutliche Beeinflussungen von mineralogischen, bodenchemischen und bodenmikrobiologischen Parametern nachgewiesen werden. Einige der erhobenen Parameter zeigten keinen linearen Zusammenhang mit zentralen Einflussfaktoren wie der Temperatur sondern einen sigmoiden Verlauf, wobei die stärksten Änderungen im mittleren, sogenannten alpin-nivalen Ökoton, in einer Höhe von ca. 3.000 m erfolgten. Der alpin-nivale Ökoton zeigte auch (festgestellt über den Nivalitätsindex) eine zentrale Grenze in der Vegetationsgesellschaft an, die mit Veränderungen der mikrobiellen Communities und Aktivitäten einherging. Dies betraf nicht nur Gesamtzahlen von Bacteria sondern auch die Abundanz methanogener Archaea, die für den Methankreislauf und damit den Klimawandel hochrelevant sind und bis zu einer Höhe von 3.497 m nachgewiesen werden konnten

Sorptive stabilization of organic matter by amorphous Al hydroxide

Amorphous Al hydroxides (am-Al(OH)3) strongly sorb and by this means likely protect dissolved organic matter (OM) against microbial decay in soils. We carried out batch sorption experiments (pH 4.5; 40 mg organic C L-1) with OM extracted from organic horizons under a Norway spruce and a European beech forest. The stabilization of OM by sorption was analyzed by comparing the CO2 mineralized during the incubation of sorbed and non-sorbed OM. The mineralization of OM was evaluated based in terms of (i) the availability of the am-Al(OH)3, thus surface OM loadings, (ii) spectral properties of OM, and (iii) the presence of phosphate as a competitor for OM. This was done by varying the solid-to-solution ratio (SSR = 0.02-1.2 g L-1) during sorption. At low SSRs, hence limited am-Al(OH)3 availability, only small portions of dissolved OM were sorbed; for OM from Oa horizons, the mineralization of the sorbed fraction exceeded that of the original dissolved OM. The likely reason is competition with phosphate for sorption sites favouring the formation of weak mineral-organic bindings and the surface accumulation of N-rich, less aromatic and less complex OM. This small fraction controlled the mineralization of sorbed OM even at higher SSRs. At higher SSRs, i.e., with am-Al(OH)3 more available, competition of phosphate decreased and aromatic compounds were sorbed selectively, which resulted in pronounced resistance of sorbed OM against decay. The combined OC mineralization of sorbed and non-sorbed OM was 12-65% less than that of the original DOM. Sorbed OM contributed only little to the overall OC mineralization. Stabilization of OC increased in direct proportion to am-Al(OH)3 availability, despite constant aromatic C (~30%). The strong stabilization at higher mineral availability is primarily governed by strong Al-OM bonds formed under less competitive conditions. Due to these strong bonds and the resulting strong stabilization, the surface loading, a proxy for the mineral's occupation by OM, was not a factor in the mineralization of sorbed OM over a wide range of C sorption (0.2-1.1 mg C m-2). This study demonstrates that sorption to am-Al(OH)3 results in stabilization of OM. The mineral availability as well as the inorganic solution chemistry control sorptive interactions, thereby the properties of sorbed OM, and the stability of OM against microbial decay

Fermented wheat germ extract - nutritional supplement or anticancer drug?

<p>Abstract</p> <p>Background</p> <p>Fermented wheat germ extract (FWGE) is a multisubstance composition and, besides others, contains 2-methoxy benzoquinone and 2, 6-dimethoxy benzoquinone which are likely to exert some of its biological effects. FWGE interferes with anaerobic glycolysis, pentose cycle and ribonucleotide reductase. It has significant antiproliferative effects and kills tumor cells by the induction of apoptosis via the caspase-poly [ADP-ribose] polymerase-pathway. FWGE interacts synergistically with a variety of different anticancer drugs and exerted antimetastatic properties in mouse models. In addition, FWGE modulates immune response by downregulation of MHC-I complex and the induction of TNF-α and various interleukins. Data in the F-344 rat model provide evidence for a colon cancer preventing effect of FWGE.</p> <p>Clinical data from a randomized phase II trial in melanoma patients indicate a significant benefit for patients treated with dacarbazine in combination with FWGE in terms of progression free survival (PFS) and overall survival (OS). Similarly, data from studies in colorectal cancer suggested a benefit of FWGE treatment. Besides extension of OS and PFS, FWGE improved the quality of life in several studies.</p> <p>Conclusion</p> <p>In conclusion, available data so far, justify the use of FWGE as a non-prescription medical nutriment for cancer patients. Further randomized, controlled and large scale clinical studies are mandatory, to further clarify the value of FWGE as a drug component of future chemotherapy regimens.</p

Demographic, clinical and antibody characteristics of patients with digital ulcers in systemic sclerosis: data from the DUO Registry

OBJECTIVES: The Digital Ulcers Outcome (DUO) Registry was designed to describe the clinical and antibody characteristics, disease course and outcomes of patients with digital ulcers associated with systemic sclerosis (SSc). METHODS: The DUO Registry is a European, prospective, multicentre, observational, registry of SSc patients with ongoing digital ulcer disease, irrespective of treatment regimen. Data collected included demographics, SSc duration, SSc subset, internal organ manifestations, autoantibodies, previous and ongoing interventions and complications related to digital ulcers. RESULTS: Up to 19 November 2010 a total of 2439 patients had enrolled into the registry. Most were classified as either limited cutaneous SSc (lcSSc; 52.2%) or diffuse cutaneous SSc (dcSSc; 36.9%). Digital ulcers developed earlier in patients with dcSSc compared with lcSSc. Almost all patients (95.7%) tested positive for antinuclear antibodies, 45.2% for anti-scleroderma-70 and 43.6% for anticentromere antibodies (ACA). The first digital ulcer in the anti-scleroderma-70-positive patient cohort occurred approximately 5 years earlier than the ACA-positive patient group. CONCLUSIONS: This study provides data from a large cohort of SSc patients with a history of digital ulcers. The early occurrence and high frequency of digital ulcer complications are especially seen in patients with dcSSc and/or anti-scleroderma-70 antibodies