ABSTRACT

A series of graft copolymers consisting of either poly(N-isopropylacrylamide) (PNiPAAm) or poly(N,N-diethylacrylamide) (PDEAAm) as a thermo-responsive component in the polymer backbone and poly(ethyleneglycol) (PEG) were immobilized as thin films and cross-linked on a fluoropolymer substrate using low-pressure argon plasma treatment. The surface-immobilized hydrogels exhibit a transition from partially collapsed to completely swollen, which is in the range of 32-35 degrees C and corresponds to the lower critical solution temperature of the soluble polymers. The hydrogels were used as cell carriers in culture experiments with L929 mouse fibroblast cells to probe for cell adhesion, proliferation, and temperature-dependent detachment of cell layers. The fibroblast cells adhere, spread, and proliferate on the hydrogel layers at 37 degrees C and become completely detached after reducing the temperature by 3 K. The cell release characteristics were further correlated to the swelling and collapsing behavior of the hydrogel films and the polymer solutions as measured in PBS solution and RPMI cell cultivation medium. It could be shown that, long before the swelling has completed upon temperature reduction, the cells detach. This can be attributed to the large content of PEG present in the hydrogel, which weaken the cell adhesion strength to the hydrogel layers.

Wine into vinegar: It is possible to selectively oxidize ethanol into acetic acid in aqueous solution with air as the oxidant and a heterogeneous gold catalyst (see TEM image of supported gold particles) at temperatures of about 423 K and O2 pressures of 0.6 MPa. This reaction proceeds readily in aqueous acidic media with yields of up to 90 % and CO2 as the only major by‐product.

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Increasing amounts of bioethanol are being produced from fermentation of biomass, mainly to counteract the continuing depletion of fossil resources and the consequential escalation of oil prices. Today, bioethanol is mainly utilized as a fuel or fuel additive in motor vehicles, but it could also be used as a versatile feedstock in the chemical industry. Currently the production of carbon-containing commodity chemicals is dependent on fossil resources, and more than 95% of these chemicals are produced from non-renewable carbon resources. The question is: what will be the optimal use of bioethanol in a longer perspective? 

Salmon (Salmo salar) was stored in ice up to 24 d, and changes during storage were observed with sensory evaluation using the Quality Index Method (QIM), and Quantitative Descriptive Analysis (QDA), total viable counts (TVC), hydrogen sulfide (H 2 S)-producing bacteria, and instrumental texture measurements (compression test). Maximum storage time in ice was determined with QDA and fat content by Soxhlet extraction. A high correlation between QIM and storage time in ice was found. Storage time could be predicted with ± 2 d. TVC increased exponentially with storage and was dominated by H 2 S-producing bacteria after 20 d in ice, which was the maximum storage time. Texture measurements indicated softening of salmon flesh with storage.

The present study describes the abundance of major marine bacterioplankton groups and 2 bacterial genera (Pseudoalteromonas and Vibrio) in surface seawater at 24 stations around the world. Catalyzed reporter deposition-fluorescence in situ hybridization showed that Alphaproteobacteria (average relative abundance 37%, average absolute abundance 3.7 × 10 5 cells ml )] showed cosmopolitan occurrence. Principal component analysis revealed a latitudinal pattern in bacterial abundances by clustering samples according to lower and higher latitudes. This was related to significantly different relative abundances of Bacteroidetes (peaking at higher latitudes) and of unclassified Bacteria and Vibrio (both peaking at lower latitudes) between warmer and colder oceans. Relative abundances of Alphaproteobacteria (peaking at subtropical) and Gammaproteobacteria (polar stations) varied between major oceanic biomes, as did absolute abundances of Roseobacter (peaking at temperate and polar stations). For almost all groups, absolute abundances were positively correlated with nutrient concentrations in warmer oceans and negatively correlated with oxygen saturation in colder oceans. On a global scale, Roseobacter and SAR86 were correlated with chlorophyll a. Linkages of environmental parameters with relative abundances were more complex, with e.g. Bacteroidetes being associated with chlorophyll a. The finding of differing communities in warmer and colder oceans underlined the presence of biogeographical patterns among marine bacteria and the influence of environmental parameters on bacterial distribution. KEY WORDS: Marine bacterioplankton · Global quantification · Latitudinal pattern · Biogeography · CARD-FISH · PCA Resale or republication not permitted without written consent of the publisherAquat Microb Ecol 61: [179][180][181][182][183][184][185][186][187][188][189] 2010 Characterization of marine bacterial communities on larger geographical scales has been done by shotgun sequencing (Rusch et al. 2007), polymerase chain reaction (PCR)-based techniques (Baldwin et al. 2005, Pommier et al. 2007, Taniguchi & Hamasaki 2008 and catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH) (Schattenhofer et al. 2009). These studies have indicated that the composition of bacterioplankton differs between oceanic regions, probably related to oceanographic factors such as water temperature (Baldwin et al. 2005, Fuhrman et al. 2008, nutrient availability (Abell & Bowman 2005), or water masses (Teira et al. 2006, Galand et al. 2010. The analysis of a global sample set showed marked variation in bacterial community structure on the 16S rRNA sequence level, with a high degree of endemism and few cosmopolitan sequences (Pommier et al. 2007). A latitudinal gradient in species richness, comparable to observations in the animal and plant kingdoms, has been shown in this context (Pommier et al. 2007, Fuhrman et al. 2008. Terminal-restriction fragment length polymorphism (T-RFLP) demonstrated distinct microbial clusters...

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