Genomic DNA macroarrays as a tool for analysis of gene expression in Leishmania

Gene-array technologies have been applied in a wide number of organisms to study gene expression profiling under several physiological and experimental conditions. Gene-array implementations combined with the information arising from emerging genome sequencing projects are expected to be in the near future a major tool to characterize genes involved in different processes. So far, gene expression profile studies in trypanosomatids have been performed in microarrays that use a glass support to immobilize fragments of genomic DNA followed by fluorescent detection. Here, we wanted to test the potential of genomic DNA macroarrays of Leishmania infantum using nylon membranes and radioactive detection. Nylon macroarrays present a number of advantages since the processing of the membranes is based on standard Southern blotting protocols familiar to molecular biologists, and the data acquisition equipment is available to most research institutions. Nylon macroarrays were employed to search for genes showing increased mRNA abundance during an axenic differentiation of L. infantum promastigotes to amastigotes. Several clones were rescued and, after validation by Northern blot assays, these L. infantum sequences were used to screen the Leishmania major gene database. The L. major contigs with high homology to the L. infantum sequences allowed a consistent identification of the regulated genes.     

Efficient production of the Nylon 12 monomer ω-aminododecanoic acid methyl ester from renewable dodecanoic acid methyl ester with engineered Escherichia coli

The expansion of microbial substrate and product scopes will be an important brick promoting future bioeconomy. In this study, an orthogonal pathway running in parallel to native metabolism and converting renewable dodecanoic acid methyl ester (DAME) via terminal alcohol and aldehyde to 12-aminododecanoic acid methyl ester (ADAME), a building block for the high-performance polymer Nylon 12, was engineered in Escherichia coli and optimized regarding substrate uptake, substrate requirements, host strain choice, flux, and product yield. Efficient DAME uptake was achieved by means of the hydrophobic outer membrane porin AlkL increasing maximum oxygenation and transamination activities 8.3 and 7.6-fold, respectively. An optimized coupling to the pyruvate node via a heterologous alanine dehydrogenase enabled efficient intracellular L-alanine supply, a prerequisite for self-sufficient whole-cell transaminase catalysis. Finally, the introduction of a respiratory chain-linked alcohol dehydrogenase enabled an increase in pathway flux, the minimization of undesired overoxidation to the respective carboxylic acid, and thus the efficient formation of ADAME as main product. The completely synthetic orthogonal pathway presented in this study sets the stage for Nylon 12 production from renewables. Its effective operation achieved via fine tuning the connectivity to native cell functionalities emphasizes the potential of this concept to expand microbial substrate and product scopes.     

Patterns of polychaete recolonization in Queensland subtropical estuaries following severe flooding

Quantitative sampling of macrobenthos and fouling organisms in the estuarine reaches of the Calliope River and Auckland Creek, Gladstone, Australia has been conducted since November 1974, and includes the recovery period (1974–1981) following severe flooding (and flood-induced scouring) in December 1973/January 1974. Changes in numbers of the 18 most abundant species of benthic polychaetes and one encrusting serpulid (Ficopomatus uschakovi) are examined. Numbers of F. uschakovi settling on fouling panels showed a regular seasonal pattern, with a late summer maximum and a winter minimum throughout this period. The total numbers of individuals for all taxa in benthic samples followed a clear colonization pattern, with super-imposed seasonality; plateau densities were reached five years after flooding. Total numbers of the 18 most abundant polychaetes showed a similar recolonizational pattern including the seasonal variation.Generally, those species of polychaetes with similar trophic strategies displayed similar patterns of abundance throughout the period:(i) The suspended detritus feeders (F. uschakovi, Branchiomma sp., Lysilla pacifica, Amaena trilobata and Terebellides stroemi) formed a constant proportion of the population; (ii) Mobile surface detrital feeders (Glycera americana, Nephtys mesobranchia, Lumbrineris sp., Sthenolepis sp. and Poecilochaetus serpens) initially formed a high proportion of the population which diminished with time; (iii) The stationary surface detrital feeders (Magelona dakini, Paraprionospio sp., Isolda pulchella and Pseudopolydora kempi) initially formed a low proportion which increased to a maximum four to five years after flooding and subsequently declined; (iv) The sole surface deposit feeder examined (Leitoscoloplos normalis) had two peaks — in early 1975 and 1978; (v) The subsurface deposit feeders (Cossura sp., Sternaspis scutata, Euclymene sp. and Mediomastus sp.) initially formed a small proportion increasing continuously to become the most abundant group at the end of the period. It is suggested that these changes reflect changes with time in the substrate since theflood-induced scouring of these estuaries, particularly the gradual accumulation of detrital material, and the changing availability of food for the different trophic groups.     

Alarm pheromones with different functions are released from different regions of the body surface of male rats

Our previous study suggested that the alarm pheromones in rats could be divided into at least two functionally different categories: one evoking autonomic responses and the other evoking behavioral responses, and the present study was conducted to test this hypothesis. Four regions of the body surface, i.e. the whisker pad, neck, rump and perianal region, of an anesthetized male Wistar rat were electrically stimulated (donor) and, after removal of the donor, the recipient rat was introduced into the same box and its behavioral and autonomic changes were recorded. Electrical stimulation of the perianal region of anesthetized donor rats provoked the release of odor that subsequently augmented core body temperature in other awake male rats. By contrast, electrical stimulation of the whisker pad of anesthetized donor males provoked the release of odor that augmented sniffing, rearing and locomotor activity in other awake male subjects. These results suggest that the alarm pheromone released from the face modifies behavior and that from the anal area induces autonomic stress responses in recipients.     

From mass of body elements to fish biomass: a direct method to quantify food intake of fish eating birds

The winter diet of great crested grebe (Podiceps cristatus) was studied in the major lakes of Insubria region, N Italy, in 2000–2003 by analysing stomach and oesophagus contents of birds found dead. Winter diet of cormorant (Phalacrocorax carbo) was studied using pellet analysis. Diet was expressed in terms of numerical abundance, frequency and biomass of prey. A detailed methodology is described of how to prepare a reference collection of otoliths, pharyngeal bones and chewing pads (key-elements), essential for species-specific identification of fish remains in stomachs and pellets, and to estimate ingested fish biomass. Correlations between mass (mg) of key-elements and mass of corresponding fish were significant, and exponential regression models were used to calculate biomass of each single prey item directly from the mass of its key-elements. Advantages of this method are compared with the more traditional two step approach in which size of elements is used to estimate fish length, followed by calculating fresh mass from fish length. Cyprinids formed the largest part of the diet for both predators. Great crested grebes selected small prey, feeding mainly on bleak (Alburnus alburnus alborella), while diet composition of cormorants varied significantly in relation to prey availability. Handling editor: K. Martens     

Material properties of the human calcaneal fat pad in compression: experiment and theory

The structural behaviour of the human heel pad has been studied extensively due to its ability to absorb shock, protect against excessive local stress, and reduce plantar pressures. However, the material properties of the tissue have not been adequately measured. These must be known in order to perform a finite element analysis of the effect of factors such as foot geometry and shoe/surface construction on heel pad function. Therefore, the purposes of this study were to (a) measure the viscoelastic behaviour of the fat pad in compression, and (b) to determine an appropriate constitutive equation to model the tissue. A series of unconfined compression tests were performed on 8 mm diameter cylinders of fat pad tissue, consisting of quasi-static, 175, 350 mm/s and stress-relaxation tests to 50% deformation. The tissue exhibited nonlinear, viscoelastic behaviour. No significant difference was found in the quasi-static behaviour between samples from different locations and orientations in the heel. The stress-relaxation tests were used to determine the time constant (τ₁=0.5 s), the 175 mm/s test to determine the relaxation coefficient (g₁=28), and the 350 mm/s compression test to determine the material constants (C₁₀₀=C₀₁₀=0.01, C₂₀₀=C₀₂₀=0.1 Pa) of a single-phase, hyperelastic, linear viscoelastic strain energy function (r²=0.98).     

纺织精练中碱性果胶酶稳定性的改进研究

从碱性果胶酶在纺织清洁生产中的应用条件出发,在60℃和pH 9.1左右,系统研究了不同稳定剂对提高碱性果胶酶的稳定性的影响。由此,得到了对酶稳定性作用较突出的添加剂以及复合稳定剂,较佳配方为乙酸钠6%(m/v)、MgCl2.2H2O 2%(m/v)。结果表明,添加稳定剂后的碱性果胶酶在棉织物精练中的应用特性得到了提高,达到了棉织物精练的需要。     

Image-based midsole insert design and the material effects on heel plantar pressure distribution during simulated walking loads

The primary objective of this paper is to study the use of medical image-based finite element (FE) modelling in subject-specific midsole design and optimisation for heel pressure reduction using a midsole plug under the calcaneus area (UCA). Plugs with different relative dimensions to the size of the calcaneus of the subject have been incorporated in the heel region of the midsole. The FE foot model was validated by comparing the numerically predicted plantar pressure with biomechanical tests conducted on the same subject. For each UCA midsole plug design, the effect of material properties and plug thicknesses on the plantar pressure distribution and peak pressure level during the heel strike phase of normal walking was systematically studied. The results showed that the UCA midsole insert could effectively modify the pressure distribution, and its effect is directly associated with the ratio of the plug dimension to the size of the calcaneus bone of the subject. A medium hardness plug with a size of 95% of the calcaneus has achieved the best performance for relieving the peak pressure in comparison with the pressure level for a solid midsole without a plug, whereas a smaller plug with a size of 65% of the calcaneus insert with a very soft material showed minimum beneficial effect for the pressure relief.     

Wachstumsuntersuchungen an Bullen des Schwarzbunten Milchrindes (SMR) bei niedrigem Fütterungsniveau

Artificially dried ryegrass, untreated and ammonia‐treated wheat straw were ground and incubated in nylon bags in the rumen of three sheep each fed with diets based on roughage or concentrate. Dry matter degradability, the concentration and the release of the trace elements Cu, Fe, Mn and Zn from the incubated feeds were measured after 0 (washing loss), 6, 12, 24, 48 and 72 h rumen incubation time.

Dry matter degradability, trace element concentration and their release were significantly influenced by the kind of incubated feeds, incubation time and feeding of sheep.

Cu‐ (1.8–6.9 mg kg^?1 DM) and Zn concentrations (36–103 mg kg^?1 DM) of straw residues in the bags were much higher than those of original straw (1.2–1.6 and 8.1–9.9 mg kg^?1 DM resp.).

The inflow of Cu and Zn in the bags containing straw residues was higher than their release. The Cu‐, Fe‐ and Mn‐release from ryegrass was similar to the dry matter degradability, but the Zn‐release was much lower.     

Spatial-dependent mechanical properties of the heel pad by shear wave elastography

The heel pad plays an important role in gait, and its biomechanical behavior and functionality are determined by its specialized architecture and mechanical properties. The purpose of this study was to apply supersonic shear wave elastography, an ultrasound-based noninvasive modality that can quantitatively estimate the shear stiffness of the tissue, to investigate the spatial-dependent mechanical properties of the heel pad. Measurements were conducted in 40 heel pads of 20 normal participants aged between 20 and 30 years by shear wave elastography. The continuous change in local shear stiffness of the heel pad along the depth direction of the heel pad was measured. The result showed that the mechanical properties of the heel pad were highly heterogeneous but followed a simple and specific pattern that local heel pad shear stiffness was highest beneath the plantar skin and decreased continuously with increasing depth. This finding provides a better understanding of the heel pad biomechanics and basis for further investigation of the heterogeneous properties of the heel pad.