Optimization of horse chestnut (<Emphasis Type="Italic">Aesculus hippocastanum</Emphasis> L.) somatic embryo conversion

Factors affecting conversion of horse chestnut (A. hippocastanum L.) somatic embryos into plantlets were evaluated. Anther filament derived embryogenic tissue developed bipolar structures with two cotyledons and a well-developed shoot and root apical meristem upon auxin omittance from the culturing medium. The impact of carbohydrate type (glucose, fructose, sucrose and maltose) and concentration (3 and 6%) on somatic embryo maturation and conversion were evaluated. Although conversion frequencies were high for all treatments, overall quality of regenerated plantlets was poor. Increasing the carbohydrate concentration in the maturation medium did not increase conversion of somatic embryos or quality of regenerated plantlets in terms of shoot height. On the contrary, addition of PEG (polyethylene glycol) in maturation media had a beneficial effect on shoot quality of regenerated plantlets. Sucrose was a superior carbon source when PEG was included in the maturation medium, in terms of conversion rate (65.7%) as well as of shoot quality of plantlets (43.8% of plantlets had shoots >2 cm). Clonal fidelity of the different development stages of somatic embryogenesis and of converted plantlets was assessed by flow cytometry and no major ploidy changes were found.     

The philosophical "mind-body problem" and its relevance for the relationship between psychiatry and the neurosciences

Parallel to psychiatry, "philosophy of mind" investigates the relationship between mind (mental domain) and body/brain (physical domain). Unlike older forms of philosophy of mind, contemporary analytical philosophy is not exclusively based on introspection and conceptual analysis, but also draws upon the empirical methods and findings of the sciences. This article outlines the conceptual framework of the "mind-body problem" as formulated in contemporary analytical philosophy and argues that this philosophical debate has potentially far-reaching implications for psychiatry as a clinical-scientific discipline, especially for its own autonomy and its relationship to neurology/neuroscience. This point is illustrated by a conceptual analysis of the five principles formulated in Kandel's 1998 article "A New Intellectual Framework for Psychiatry." Kandel's position in the philosophical mind-body debate is ambiguous, ranging from reductive physicalism (psychophysical identity theory) to non-reductive physicalism (in which the mental "supervenes" on the physical) to epiphenomenalist dualism or even emergent dualism. We illustrate how these diverging interpretations result in radically different views on the identity of psychiatry and its relationship with the rapidly expanding domain of neurology/neuroscience.     

Fermented liquid feed for pigs

Since the announcement of the ban on the use of antibiotics as antimicrobial growth promoters in the feed of pigs in 2006 the investigation towards alternative feed additives has augmented considerably. Although fermented liquid feed is not an additive, but a feeding strategy, the experimental work examining its possible advantages also saw a rise. The use of fermented liquid feed (FLF) has two main advantages, namely that the simultaneous provision of feed and water may result in an alleviation of the transition from the sow milk to solid feed and may also reduce the time spent to find both sources of nutrients, and secondly, that offering FLF with a low pH may strengthen the potential of the stomach as a first line of defence against possible pathogenic infections. Because of these two advantages, FLF is often stated as an ideal feed for weaned piglets. The results obtained so far are rather variable, but in general they show a better body weight gain and worse feed/gain ratio for the piglets. However, for growing-finishing pigs on average a better feed/gain ratio is found compared to pigs fed dry feed. This better performance is mostly associated with less harmful microbiota and better gut morphology. This review provides an overview of the current knowledge of FLF for pigs,dealing with the FLF itself as well as its effect on the gastrointestinal tract and animal performance.     

In vitro fermentability and physicochemical properties of fibre substrates and their effect on bacteriological and morphological characteristics of the gastrointestinal tract of newly weaned piglets

Fermentability of fibre has a great impact on the bacterial flora along the gastrointestinal tract of newly weaned piglets. Therefore, this parameter was determined by incubating in vitro different fibre substrates (chicory roots, sugar beet pulp, wheat bran and corn cobs) with contents of jejunum or caecum sampled from slaughtered pigs. Incubating with small intestinal contents, lactic acid was the only fermentation product. Fermentability was highest for chicory roots, followed by wheat bran and sugar beet pulp, while corn cobs were not fermented. Based on SCFA formed in the incubations with caecal contents, ranking of the fermentability of the fibre substrates was in the same order. The effect of adding different fibre substrates to diets of newly weaned piglets on bacteriological and morphological aspects of the gastrointestinal tract was also investigated. In Experiment 1 three groups of five piglets, weaned at four weeks of age, received a control feed (C), C supplemented with corn cobs (50 g/kg) or with chicory roots (20 g/kg). In Experiment 2, diet C was supplemented with sugar beet pulp (120 g/kg) or with wheat bran (75 g/kg). After three weeks animals were euthanized and digesta were sampled from stomach, proximal and distal jejunum, caecum and colon. Furthermore, mucosal scrapings were prepared and tissue samples were taken from jejunum, caecum and colon. Viscosity was determined for jejunal, caecal and colon contents. Corn cobs in the feed increased the number of total bacteria, lactobacilli and bifidobacteria in the stomach and proximal duodenum, while a decreased count of streptococci in distal jejunum contents was noted. Chicory roots increased the counts of Escherichia coli in the distal jejunum and on the mucosa, while sugar beet pulp decreased the number of lactobacilli on the mucosa only. Wheat bran seemed to increase the count of E. coli in jejunal digesta and on the mucosa, and also the number of lactobacilli in the stomach and jejunum. Bifidobacterial numbers were increased but only in the proximal part of the jejunum. Fibre substrates affected the concentration of lactate and SCFA in different parts of the intestinal tract. Feeding corn cobs increased villus length in the proximal jejunum by 13%. The number of intra-epithelial lymphocytes in the villous epithelium of proximal and distal jejunum was decreased by corn cobs and chicory roots supplementation while beet pulp and wheat bran had the opposite effect. In Experiment 1, apoptotic index of the mucosa of the distal jejunum was very low and decreased when corn cobs were fed. Mitotic index in the crypts was only affected by the wheat bran diet and a small decrease was noted. It was concluded that the fermentability of fibre was not an ideal criterion for predicting its effects on the flora. The effect of fibres on viscosity of digesta was negligible probably explaining the lack of clear and consistent influences on the intestinal mucosa.     

Mixed biodiversity benefits of agri-environment schemes in five European countries

Agri-environment schemes are an increasingly important tool for the maintenance and restoration of farmland biodiversity in Europe but their ecological effects are poorly known. Scheme design is partly based on non-ecological considerations and poses important restrictions on evaluation studies. We describe a robust approach to evaluate agri-environment schemes and use it to evaluate the biodiversity effects of agri-environment schemes in five European countries. We compared species density of vascular plants, birds, bees, grasshoppers and crickets, and spiders on 202 paired fields, one with an agri-environment scheme, the other conventionally managed. In all countries, agri-environment schemes had marginal to moderately positive effects on biodiversity. However, uncommon species benefited in only two of five countries and species listed in Red Data Books rarely benefited from agri-environment schemes. Scheme objectives may need to differentiate between biodiversity of common species that can be enhanced with relatively simple modifications in farming practices and diversity or abundance of endangered species which require more elaborate conservation measures.     

Optimal foraging on perilous prey: risk of bill damage reduces optimal prey size in oystercatchers

Intake rate maximization alone is not always sufficient in explainingprey size selection in predators. For example, bivalve-feedingoystercatchers regularly select smaller prey than expected ifthey aimed to maximize their intake rate. It has been proposedthat to these birds large prey are "risky," in the sense thatbirds may damage their bills when feeding on large bivalves.Large bivalves yield more energy, but according to this hypothesisthis is achieved at the expense of energy yield in the longterm when (1) the risk of bill damage increases with prey sizeand (2) foraging with a damaged bill is less effective. In accordancewith this hypothesis, we show that captive oystercatchers feedingon large cockles experienced a high probability of bill tipdamage, while bill damage was absent when cockles were small.Moreover, among free-living oystercatchers the prevalence ofbill damage was correlated with mean cockle size near the capturesite, and the data on captive birds fit in this pattern. Foodintake of captive oystercatchers feeding exclusively on cockleswas reduced by 23% after bill damage, and free-living birdswith damaged bills had 14 g lower mass. Because lower body masswas associated with higher mortality probability, these resultsindicate long-term costs associated with feeding on large cockles.We conclude that the risk of bill damage can potentially explainwhy oystercatchers avoid large bivalves and that oystercatchersmay maximize long-term intake rate by selecting prey sizes thatare "suboptimal" from a short-term rate-maximizing point ofview.     

Metabolic activity of Staphylococcus epidermidis is high during initial and low during late experimental foreign-body infection

Foreign-body infection (FBI) is notoriously resistant to eradication by antibiotic treatment. It is hypothesized that reduced bacterial metabolic activity contributes to this resistance. We examined the metabolic activity of Staphylococcus epidermidis in 204 samples recovered during in vitro foreign-body colonization and in 424 samples recovered during in vivo FBI in a rat model. Metabolic activity was measured by determining the amount of 16S rRNA per genome by quantitative PCR. The initial foreign-body-associated growth proved to be a metabolically active process, both in vitro and in vivo. The initial 16S rRNA content was similar to that observed during in vitro exponential-growth phase. However, during late in vivo FBI, a 114-fold (P < 0.0001) decrease in the 16S rRNA content was observed, indicating that there was markedly decreased metabolic activity. This decreased metabolic activity during late FBI can explain at least in part why such infections are so difficult to eradicate with conventional antibiotic treatment.     

Growth-substrate dependent dechlorination of 1,2-dichloroethane by a homoacetogenic bacterium

A rod shaped, gram positive, non sporulating Acetobacterium strain was isolated that dechlorinated 1,2-dichloroethane (1,2-DCA) to ethene at a dechlorination rate of up to 2 nmol Cl^- min^-1 mg^-1 of protein in the exponential growth phase with formate (40 mM) as the substrate. Although with other growth substrates such as pyruvate, lactate, H₂/CO₂, and ethanol higher biomass productions were obtained,the dechlorination rate with these substrates was more than 10-fold lower compared with formate growing cells. Neither cell extracts nor autoclaved cells of the isolatedAcetobacterium strain mediated the dechlorination of 1,2-DCA at significant rates. The addition of 1,2-DCA to the media did not result in increased cell production. No significant differences in corrinoid concentrations could be measured in cells growing on several growth-substrates. However, these measurements indicated that differences in corrinoid structure might cause the different dechlorination activity. The Acetobacterium sp. strain gradually lost its dechlorination ability during about 10 transfers in pure culture, probably due to undefined nutritional requirements. 16S rDNA analysis of the isolate revealed a 99.7% similarity with Acetobacterium wieringae. However, the type strains of A. wieringae and A. woodii did not dechlorinate 1,2-DCA.