Aggregation Properties of Albumin in Interacting with Magnetic Fluids

In this study, interactions of Fe₃O₄ magnetic nanoparticles with serum albumin biomolecules in aqueous solutions were considered. The studies were conducted with the laser correlation spectroscopy and optical analysis of dehydrated films. It was shown that the addition of magnetite to an albumin solution at low concentrations of up to 10⁻⁶ g/L led to the formation of aggregates with sizes of up to 300 nm in the liquid phase and an increase in the number of spiral structures in the dehydrated films, which indicated an increase in their stability. With a further increase in the magnetite concentration in the solution (from 10⁻⁴ g/L), the magnetic particles stuck together and to albumin, thus forming aggregates with sizes larger than 1000 nm. At the same time, the formation of morphological structures in molecular films was disturbed, and a characteristic decrease in their stability occurred. Most stable films were formed at low concentrations of magnetic nanoparticles (less than 10⁻⁴ g/L) when small albumin–magnetic nanoparticle aggregates were formed. These results are important for characterizing the interaction processes of biomolecules with magnetic nanoparticles and can be useful for predicting the stability of biomolecular films with the inclusion of magnetite particles.     

Probiotic and milk technological properties of Lactobacillus brevis

Two Lactobacillus brevis strains ATCC 8287 and ATCC 14869(T), were evaluated for their applicability as putative probiotics in dairy products. The strains expressed good in vitro adherence to human Caco-2 and Intestine 407 cells and tolerated well low pH, bile acids and pancreatic fluid under in vitro conditions. In antimicrobial activity assays, strain ATCC 8287 showed inhibitory properties toward selected potential harmful microorganisms, particularly against Bacillus cereus. Both L. brevis strains were resistant to vancomycin, which is typical for the genus Lactobacillus. The L. brevis strains were not able to acidify milk to yoghurt but were suitable as supplement strains in yoghurts. This was shown by producing a set of yoghurt products and analysing their rheological and sensory properties during a cold storage period of 28 days. Survival of the strains through human intestine was examined in 1-week feeding trials. Despite its human origin, L. brevis ATCC 14869(T) could not survive through the gastrointestinal (GI) tract, whereas L. brevis ATCC 8287 was detected in the faecal samples taken during and immediately after ingestion of the strain. In conclusion, L. brevis ATCC 8287 is a promising candidate as a probiotic supplement in dairy products.     

Insectivorous Birds Are Attracted by Plant Traits Induced by Insect Egg Deposition

Insectivorous birds feed upon all developmental stages of herbivorous insects, including insect eggs if larvae and adults are unavailable. Insect egg deposition on plants can induce plant traits that are subsequently exploited by egg parasitoids searching for hosts. However, it is unknown whether avian predators can also use egg-induced plant changes for prey localization. Here, we studied whether great tits (Parus major) and blue tits (Cyanistes caeruleus) are attracted by traits of the Scots pine (Pinus sylvestris) induced by pine sawfly (Diprion pini) egg deposition. We chose this plant – insect system because sawfly egg deposition on pine needles is known to locally and systemically induce a change in pine volatile organic compounds (VOCs), and tits are known to prey upon sawfly eggs. In dual choice laboratory experiments, we simultaneously offered the birds an egg-free control branch and a systemically egg-induced branch. Significantly more birds visited the egg-induced branch first. We confirmed by GC-MS analyses that systemically egg-induced branches released more (E)-β-farnesene compared to control branches. Spectrophotometric analyses showed that control branches reflected more light than egg-induced branches throughout the avian visual range. Although a discrimination threshold model for blue tits suggests that the birds are poor at discriminating this visual difference, the role of visual stimuli in attracting the birds to egg-induced pines cannot be discounted. Our study shows, for the first time, that egg-induced odorous and/or visual plant traits can help birds to locate insect eggs without smelling or seeing those eggs.     

R&D vs. Other Factor Inputs in a High-Tech Industry

According to knowledge-based growth theories, catch-up with the global technology frontier calls for a shift from physical investment to innovation. This prevailing premise in Finland is tested with an unbalanced panel of firms in Finnish information and communications technology (ICT) manufacturing, over a period of rapid growth, 1990–2003. Stochastic frontier model estimation results are overwhelmed by scale elasticity associated productivity growth. Contrary to beliefs, R&D productivity was relatively low, regardless if measured by efficiency impacts of R&D intensity, technical change or R&D elasticity of output. Results are consistent with industry outcomes and reveal internal causes to the subsequent downfall of ICT manufacturing in Finland.     

Spoilage of value-added, high-oxygen modified-atmosphere packaged raw beef steaks by Leuconostoc gasicomitatum and Leuconostoc gelidum

Moisture-enhancing and marinating of meats are commonly used by the meat industry to add value to raw, retail products. Recently in Finland, certain value-added beef steak products have proven to be unusually susceptible to microbial spoilage leading to untoward quality deteriorations during producer-defined shelf-life. This study was conducted to evaluate the role of lactic acid bacteria (LAB) in the premature spoilage of value-added beef packaged under high-oxygen modified atmospheres. Spoilage was characterised by green discolouration and a buttery off-odour. The predominant LAB in eight packages of spoiled, marinated or moisture-enhanced beef steaks were identified by reference to a 16 and 23S rRNA gene restriction fragment length polymorphism pattern (ribotype) database. Leuconostoc gasicomitatum, Leuconostoc gelidum, Lactobacillus algidus, Lactobacillus sakei and Carnobacterium divergens were found to predominate in the LAB populations at numbers above 10(8) CFU/g. Inoculation of moisture-enhanced steaks with LAB strains and strain mixtures originating from the spoiled products demonstrated the spoilage potential of L. gasicomitatum and L. gelidum isolates. These two species produced green surface discolouration and buttery off-odours similar to these found in the spoiled, commercial products.     

Red clover (Trifolium pratense L.) isoflavones: root phenolic compounds affected by biotic and abiotic stress factors

BACKGROUND: Phenolic compounds have recently received considerable attention for their ability to protect plant and human cells from oxidative stress‐induced damage. Red clover (Trifolium pratense L.) is a rich source of isoflavonoids with multiple potential protective functions. The aim of this study was to identify and characterise phenolic compounds in red clover roots by high‐performance liquid chromatography and mass spectrometry and to study the effects of stress factors and growth stage on root phenolics. RESULTS: A total of 28 phenolic compounds were tentatively identified in red clover roots. The most abundant phenolics in pot‐grown roots were formononetin glycoside malonate (G‐M) (1.51–4.26 mg g^?1), formononetin (2.21–3.57 mg g^?1) and biochanin A (1.73–2.17 mg g^?1), whereas field‐grown roots were rich in formononetin‐G‐M (3.90–4.27 mg g^?1), maackiain‐G‐M (2.35–3.02 mg g^?1) and pseudobaptigenin‐G‐M (1.80–2.58 mg g^?1). Concentrations were affected by the growth stage. Ozone exposure slightly affected the total phenolic content in roots and also had minor effects on individual compounds. CONCLUSION: Elevated ozone, cultivation regime and growth stage affected the levels of phenolics in red clover roots, suggesting sensitivity of root phenolics to biotic and abiotic stress conditions. The high levels of phenolics found in roots even in late autumn may be utilised in many applications. Copyright © 2009 Society of Chemical Industry     

Leaf Volatile Emissions of <Emphasis Type="Italic">Betula pendula</Emphasis> during Autumn Coloration and Leaf Fall

Deciduous trees remobilize the nitrogen in leaves during the process of autumn coloration, thus providing a high quality food source for aphids preparing to lay over-wintering eggs. It has been suggested that aphids may use volatile organic compounds (VOCs) to: (a) select leaves where nutrient remobilization has started and induced defenses are reduced; and (b) detect the time of leaf abscission. We analyzed VOCs emitted by the foliage of Betula pendula Roth. during autumn coloration and from leaf litter just after leaf fall. We tested the hypothesis that costly, photosynthesis-related terpenes and other herbivore-induced VOCs related to attraction of aphid parasitoids and predators are reduced during the coloration process. We also investigated if the VOC emission profile of abscising leaves is different from that of early stage yellowing leaves. Enemy-luring compounds (E)-β-ocimene, linalool, and (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) were emitted only from the green foliage. Methyl salicylate (MeSa), known to recruit predatory bugs and attract migrant aphids, was emitted until the first stage of color change. Cis-3-hexenol, an indicator of cellular disintegration, became dominant in the emissions from abscising leaves and from fresh leaf litter. We discuss the ecological significance of the observed changes in birch leaf VOC profiles during the process of autumn senescence.