Glucons?ureverg?rung durch Milchs?urebakterien des Weines

Zusammenfassung Insgesamt 116 verschiedene, überwiegend aus Wein isolierte Stämme von Milchsäure-bakterien der GattungenLactobacillus, Leuconostoc, Pediococcus undStreptococcus wurden auf die Fähigkeit zur Verwertung von Gluconsäure untersucht. Bis auf einzelne Ausnahmen wurde Gluconsäure von denLactobacillus-Arten, die den UntergattungenStreptobacterium undBetabacterium angehörten, und der Mehrzahl derLeuconostoc-Stämme vergoren. VonPediococcus wurde Gluconsäure nicht abgebaut. Bei wachsenden Kulturen und ruhenden Zellen vonLactobacillus brevis, Lactobacillus casei undLeuconostoc oenos waren die Endprodukte des Gluconsäureabbaus Milchsäure, Essigsäure, Äthanol und CO₂. Milchsäure entsteht aus Gluconsäure in annähernd äquimolaren Mengen. In einem aus Wein und Hefeextrakt bestehenden Medium (pH 3,5) wurden 0,5 g Gluconsäure und 4,5 g Äpfelsäure je 1 vonLactobacillus brevis undLeuconostoc oenos vollständig abgebaut.

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Fermentation of gluconic acid by lactic acid bacteria isolated from wine

Summary The fermentation of gluconic acid was investigated in 116 different strains of lactic acid bacteria belonging to the generaLactobacillus, Leuconostoc, Pediococcus andStreptococcus. Most of the strains were isolated from wine. Gluconic acid was fermented by nearly all species of the genusLactobacillus (belonging to the subgeneraStreptobacterium andBetabacterium and by most strains ofLeuconostoc. The pediococci did not ferment gluconic acid. Growing cultures and resting cells ofLactobacillus brevis, Lactobacillus casei andLeuconostoc oenos formed lactic acid, acetic acid, ethanol and CO₂ from gluconic acid. Lactic acid was formed in about equimolar amounts from gluconic acid.Lactobacillus brevis andLeuconostoc oenos metabolised completely 0.5 g of gluconic acid and 4.5 g of malic acid per liter when cultured in a medium consisting of wine and a small amount of yeast extract (at pH 3.5).

     

Metal-ion-induced formation and stabilization of protein cages based on the cowpea chlorotic mottle virus

The cowpea chlorotic mottle virus (CCMV) is a versatile building block for the construction of nanoreactors and functional materials. Upon RNA removal, the capsid can be reversibly assembled and disassembed by adjusting the pH. At pH 5.0 the capsid is in the native assembled conformation, while at pH 7.5 it disassembles into 90 capsid protein dimers. This special property enables the encapsulation of various molecules, such as protein and enzymes, but only at low pH. It is possible to stabilize the capsid at pH 7.5 by addition of negatively charged polyelectrolytes or negatively charged particles, but these methods all fill the interior of the capsid, leaving little or no space for other cargo molecules. This pH restriction therefore severely limits the range of enzymes that can be encapsulated, and hampers the investigation of the CCMV capsid as a nanoreactor for the study of enzymes in confined spaces. Herein, the interaction of N-terminal histidine-tag-modified capsid proteins with several metal ions is reported. Depending on the conditions used, nanometer-sized protein particles or capsidlike architectures are formed that are stable at pH 7.5. This metal-mediated stabilization methodology is employed to form stable capsids containing multiple proteins at pH 7.5, thereby greatly expanding the scope of the CCMV capsid as a nanoreactor.     

L?slichkeit und gel-elektrophoretische Muster hitzedenaturierter Proteine, auch von st?rkehaltigen Proben, nach Einwirkung von Na-dodecylsulfat (SDS)

Zusammenfassung Das Lösungsvermögen des Anionendetergents Na-dodecylsulfat (SDS) in Gegenwart disulfidbrückenspaltender Reagentien auf native und auf hitzedenaturierte Proteine wird an Fleisch-und Kartoffelproteinen mit Hilfe elektrophoretischer Methoden untersucht. Die zur Resolubilisierung notwendige Menge an SDS und die erforderliche Incubationszeit werden für die verschiedenen Proben ermittelt. Die Proteine des Skeletmuskels von Rind, Schwein, Huhn und Pute einerseits und die Proteine der europäischen Kartoffelsorten und der südamerikanischen Primitivkultivare andererseits zeigen in der SDS-PAGE ein sehr ähnliches Bandenmuster, das speziesdifferenzierend kaum ausgewertet werden kann, aber ein gutes Charakteristikum für Muskel-bzw. Kartoffelproteine ist.

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Solubility and electrophoretic patterns of heat-denaturated proteins (including samples containing starch) after treatment with SDS (sodiumdodecylsulfat)

Summary The ability of the anionic detergent SDS (sodium-dodecylsulfate) to solubilize native and heat-denaturated proteins of meat and potatoes in presence of disulphide reducing agents was checked by electrophoretic methods. Skeletal muscle proteins of beef, pork, chicken and turkey have shown very similar patterns in SDS-gelelectrophoresis, which could hardly be used for species identification but they are characteristic for fresh or boiled muscles. Proteins of European potato cultivars and primitive cultivars from South America have almost identical SDS-patterns even if taken from boiled potatoes. Their patterns are different from the proteins of other European crops plants and may serve for detection of the presence of potatoes in food mixtures.

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Diese Arbeit ist Teil der Dissertation von I. de Wreede. Die Analyse der tierischen Proteine bearbeitete I. de Wreede.Sonderdruckanfragen an: I. de Wreede (Adresse siehe oben)     

Enhanced mechanical properties of epoxy composites using cellulose micro- and nano-crystals

Epoxy polymers are commonly utilized in structural applications due to their high bearing capacity and excellent chemical resistance. However, their inherent brittleness poses a significant challenge for their use in high shock and fracture strength products. To address this shortcoming, fillers can be incorporated into the polymer during preparation. In this study, we aimed to investigate the effect of incorporating cellulose-based fillers, namely cellulose nanocrystals (CNCs) and microcrystalline cellulose (MCC), on the mechanical properties of epoxy polymer composites. The study evaluated the impact of various factors, including filler concentration, particle size, and moisture content, on the mechanical properties of the composites. The results demonstrated that the incorporation of CNC or MCC powders at concentrations below 5% could enhance the mechanical properties of the resulting epoxy composites without adversely affecting their surface and thermal properties. The maximum tensile strength and fracture toughness of the filler-based epoxy composites were achieved at 2 and 4 wt% for CNCs and MCC, respectively. CNCs with a smaller particle size distribution were found to be much more effective than MCC in improving the mechanical properties of the epoxy composites. Furthermore, utilizing dried fillers resulted in a higher improvement in tensile strength, which was achieved at lower filler concentrations.     

Desalination of a brick by application of an electric DC field

Salts in masonry can cause various problems as decay of the masonry itself, lost adhesion of plaster and hygroscopic moisture. Chlorides are among the most common building salts and the present paper is focused on removal of chlorides from a brick in an applied electric field as a step towards developing an electrochemical desalination method for brick masonry. Experiments were conducted in laboratory scale with one type of bricks that were contaminated with either NaCl or KCl through submersion in salt solutions prior to application of current. It was seen that NaCl was slower supplied to the brick during submersion and slower removed in the applied electric field than KCl. This indicates that the removal rate of chloride depends on the associated cation and this must be taken into account when desiding the duration of full scale actions. The electrochemical desalination was very efficient and 99% removal of chloride was obtained. The final concentration in the brick after treatment was less than 10 mg Cl/kg and this concentration is unproblematic. When low salt concentrations were reached during the electrochemical treatment, electroosmotic dewatering of the brick started, showing that electroosmotic dewatering occurs at low ionic concentrations.     

Some aspects of the intraregional spatial distribution of local sector activities

This paper focuses on the spatial distribution of economic activities that serve the demands of households within a region. The level of local sector activities is measured by employment per inhabitant. The basic hypothesis relates to how this proportion varies systematically over space for a wide range of geographies, from high values in a city center to low values in areas adjacent to the city center, and asymptotically approaching the average regional level as the distance from the center increases. This defines a curve that we (under quite general conditions) find to be invariant under changes in the spatial residential pattern and the transportation structure. This suggests that relationships of this kind might be a powerful tool in the prediction of regional development.

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Use of biofuel ashes for fertilisation of Betula pendula seedlings on nutrient-poor peat soil

Short-term effects of different doses (0.25; 0.5 and 1.0 kg m^?2) of wood ash (WA), peat ash (PA) and their mixture (MA) applied to peat substrate on the mineral composition and growth of seedlings of Betula pendula were investigated. The experiments were conducted with 1-year-old seedlings planted in vegetation pots. The pH of the substrate was increased by 0.4–0.9 units during the vegetation period compared to the control. The peat substrate was poor in nutrients, except N. The substrate treated with WA had higher concentrations of K, Mg, Mn, Fe, P, Zn, Cr and Pb, but a lower N concentration compared to the control. The substrate treated with PA had higher concentrations of Ca, Mg, N and P. The concentrations in the MA treatment were intermediate between WA and PA. The ashes increased K and lowered the concentration of Ca. A decrease in N in seedlings was found under the influence of WA and MA. An increase in K and P was found in all compartments of seedlings, while the concentrations of Ca, Mg, Cu, Zn, Cd and Cr in seedlings were affected irregularly depending on types and doses of ashes used. The uptake of Cd, Cr and Pb did not reach phytotoxic levels; however, increased concentrations of Cd and Pb were found in roots. A positive influence of ash application on growth was found. The heights and root collar diameters of all ash-fertilised treatments exceeded those of the control seedlings in most cases.     

Constructing users in the smart grid—insights from the Danish eFlex project

The smart grid is promoted as one of the key elements in a low-carbon transition in many countries. In Denmark, the dominant framing of the smart grid emphasises the challenge of integrating much more wind power into the electricity system and using electricity for heating (heat pumps) and transport (electric cars). In the process of radically transforming the electricity system, strategic system builders need to align many forces, including consumers, who play an important role in the functioning of such large networked systems. System builders need to explore, for instance, whether and how users can be motivated to be flexible in relation to moving electricity consumption over time. This paper reports on one of the first smart-grid-related projects in Denmark in which consumer aspects have been central and where potentials for flexible electricity consumption have been tested. The aim of the paper is to explore what can be learned from such experiments and which roles they play in the construction of the smart grid. In this context, the concept of the ‘aligned user’ is introduced.