Nitrite, an electron donor for anoxygenic photosynthesis

We report a previously unknown process in which anoxygenic phototrophic bacteria use nitrite as an electron donor for photosynthesis. We isolated a purple sulfur bacterium 98% identical to Thiocapsa species that stoichiometrically oxidizes nitrite to nitrate in the light. Growth and nitrate production strictly depended on both light and nitrite. This is the first known microbial mechanism for the stoichiometric oxidation of nitrite to nitrate in the absence of oxygen and the only known photosynthetic oxidation in the nitrogen cycle. This work demonstrates nitrite as the highest-potential electron donor for anoxygenic photosynthesis known so far.     

The additional costs of segregated transport to slaughter to decrease Salmonella prevalence in pork--a simulation study

A stochastic simulation model was used to assess the additional costs related to segregated transport to slaughter. This control measure was assumed to be implemented within a producers' association to decrease Salmonella prevalence in pork. Calculations were based on the additional shipments caused by the separate transport of low- and high-prevalence herds and on the additional transport distance caused by changed routing. The results showed that there is not necessarily a considerable increase in the number of shipments due to herd status separation for transport. The percentage of shipments changed due to segregated transport varied between 43% and 69% depending on the threshold prevalence. The additional costs per slaughtered pig varied between 0.07€/pig and 0.58€/pig under the given assumptions. Costs were governed by the percentage of changed shipments and the additional distance of a changed shipment. Due to the fact that the percentage of changed shipments is related to the distribution of herd prevalence within the producers' association, there is no cost-effective threshold in general. Different producers' associations incur different costs caused by segregated transport to slaughter at the same threshold prevalence. The current study supports producers' associations in evaluating the additional costs of segregated transport for their members.     

Satellite-based stand-wise forest cover type mapping using a spatially adaptive classification approach

Due to high variation in forest communities, forest structure and the fragmentation of the forested area in Central Europe, satellite-based forest inventory methods have to meet particularly high-quality requirements. This study presents an innovative method to combine official forest inventory information at stand level with multidate satellite imagery using a spatially adaptive classification approach for producing wall-to-wall forest cover maps of important tree species and management classes across multiple ownership regions in a heterogeneous low mountain range in Germany. The classification approach was applied to a 5,200-km² area (about 2,080?km² of forest land, mostly mixed forests) located in the Eifel mountain range in Central Europe. In comparison with conventional classifiers, our results demonstrate a significant increase in classification accuracy in the order of 12%. The method was tested with ASTER images but holds the potential to be used for regular state forest inventories based on standard and novel earth observation data supplied for instance from the SPOT-5 and RapidEye sensors.     

Elastic moduli of living epithelial pancreatic cancer cells and their skeletonized keratin intermediate filament network

In simple epithelia, such as living epithelial pancreatic cancer cells (Panc-1), unusual amounts of keratin filaments can be found, which makes these cells an ideal model system to study the role of keratin for cell mechanical properties. In this work, the elastic moduli of Panc-1 cells and their extracted in-situ subcellular keratin intermediate filament network are determined and compared with each other. For this, the living adherent cells and their extracted keratin network were probed with local quasistatic indentation testing during large deformations using the Atomic Force Microscope (AFM). We determined the elastic modulus of the skeletonized but structurally intact keratin network to be in the order of 10 Pa, while the living cell elastic modulus ranged from 100 to 500 Pa. By removing microfilaments, microtubules, membranes and soluble cytoplasmic components during keratin network extraction, we excluded effects caused by crosslinking with other filamentous fibers and from the viscosity of the cytoplasm. Thus, the determined elastic modulus equals the actual elastic modulus inherent to such a keratin filamentous network. In our assessment of the effective mechanical contribution of the architecturally intact, skeletonized keratin network to living cell mechanics, we come to the conclusion that it plays only a very limited role. Evidently, the quantitative dominance of keratin in these cells does not reflect a strong influence on determining the cell's elastic modulus. Instead, keratin like other filamentous structures in the cell's scaffolding, e.g., F-actin and microtubuli, is one part of a greater whole.     

Assessing spillover from marine protected areas and its drivers: A meta‐analytical approach

Overfishing may seriously impact fish populations and ecosystems. Marine protected areas (MPAs) are key tools for biodiversity conservation and fisheries management, yet the fisheries benefits remain debateable. Many MPAs include a fully protected area (FPA), restricting all activities, within a partially protected area (PPA) where potentially sustainable activities are permitted. An effective tool for biodiversity conservation, FPAs, can sustain local fisheries via spillover, that is the outward export of individuals from FPAs. Spillover refers to both: “ecological spillover”: outward net emigration of juveniles, subadults and/or adults from the FPA; and “fishery spillover”: the fraction of ecological spillover that directly benefits fishery yields and revenues through fishable biomass. Yet, how common is spillover remains controversial. We present a meta‐analysis of a unique global database covering 23 FPAs worldwide, using published literature and purposely collected field data, to assess the capacity of FPAs to export biomass and whether this response was mediated by specific FPA features (e.g. size, age) or species characteristics (e.g. mobility, economic value). Results show fish biomass and abundance outside FPAs was higher: (a) in locations close to FPA borders (<200 m) than further away (>200 m); (b) for species with a high commercial value; and (c) in the presence of PPA surrounding the FPA. Spillover was slightly higher in FPAs that were larger and older and for more mobile species. Based on the broadest data set compiled to date on marine species ecological spillover beyond FPAs' borders, our work highlights elements that could guide strategies to enhance local fishery management using MPAs.