Development of Water Stress under Increased Atmospheric CO2 Concentration

The increase in water use efficiency (the ratio of photosynthetic to transpiration rates) is likely to be the commonest positive effect of long-term elevation in CO₂ concentration (CE). This may not necessarily lead to decrease in long-term water use owing to increased leaf area. However, some plant species seem to cope better with drought stress under CE, because increased production of photosynthates might enhance osmotic adjustment and decreased stomatal conductance and transpiration rate under CE enable plants to maintain a higher leaf water potential during drought. In addition, at the same stomatal conductance, internal CO₂ concentration might be higher under CE which results in higher photosynthetic rate. Therefore plants under CE of the future atmosphere will probably survive eventual higher drought stress and some species may even be able to extend their biotope into less favourable sites. This revised version was published online in July 2006 with corrections to the Cover Date.     

Montmorillonite and Beidellite Intercalated with Tetramethylammonium Cations

Molecular mechanics simulations, combined with X-ray powder diffraction and infrared spectroscopy, have been used in structure analysis of montmorillonite and beidellite intercalated with tetramethylammonium cations. A complex structure analysis provided us with the detailed structure model, including characterization of the disorder, the total sublimation energy and a charge distribution in the structure of intercalates. The calculated basal spacings (14.36 Å for TMA-montmorillonite and 14.12 Å for TMA-beidellite) are in good agreement with the experimental values (14.31 Å for TMA-montmorillonite and 14.147 Å for TMA-beidellite). Both intercalated structures exhibit positional and orientational disorder in the arrangement of TMA cations, and consequently disorder in layer-stacking. In the present work we analyse the effect of octahedral and tetrahedral substitutions in a 2:1 silicate layer on the arrangement of tetramethylammonium (TMA) cations in the interlayer space of montmorillonite and beidellite. The most significant difference between TMA-montmorillonite and TMA-beidellite is in the charge distribution on the TMA cations and silicate layer. The TMA-beidellite structure is highly polarized, the total charge on one TMA cation is +0.167 e^–, while the total charge on the TMA cation in montmorillonite is +0.050 e^–.     

Urban tree root systems and their survival near houses analyzed using ground penetrating radar and sap flow techniques

Root systems of two mature Field maple trees (Acer campestre L.) growing in both shaded and non-shaded sites, on clay soil in an urban environment, were analyzed by ground penetrating radar (GPR), light microscope and sap flow techniques. The ground surface above the root systems was covered by asphalt. However, a small piece of garden existed near the non-shaded tree, and root area of roots growing in this direction increased significantly, due to a presumed increase in available water and nutrients. However, no garden was present near the shaded tree, therefore roots remaining under the asphalt surface did not increase in area in any particular direction. Maximum rooting depth of shaded and exposed trees, as determined by GPR, was approximately 1.4 and 1.7 m, respectively. The trees utilized relatively large amounts of water for transpiration, i.e. 65–140 l per fine summer day and in average 10 m³ per growing season. However, transpiration expressed per root surface area (and/or whole root system enveloping area) was practically the same in both trees, i.e. 1 dm³ m^-2 d^-1 or almost 100 dm³ m^-2 per growing season. These figures represented about 50% of potential evapotranspiration when considering projected crown areas. Increased transpiration under long-term high evaporation demands may cause occasional local drying of soil around roots, associated with soil shrinking in clay, which can be followed by serious damage to buildings.     

Semi-Quantitative Comparison of Infrared Thermography with Indocyanine Green Imaging in Porcine Intestinal Resection

BackgroundThe quality of intestinal blood supply is extremely important for healing of intestinal anastomoses. During the surgery the blood supply of the intestine may appear sufficient even though the microperfusion is not fully adequate. The degree of blood supply of remaining intestinal segment and the positioning of the resection margins is estimated subjectively by the surgeon's experience or objectively by means of indocyanine green fluorescence imaging. The subject of our study is the evaluation of the infrared thermal imaging as another supportive non-invasive imaging method in assessment of intestinal blood supply, and to compare surgeon's decisions of the position of resection line with information obtained by infrared thermal imaging and by indocyanine green fluorescence imaging.MethodsA pilot study on thermal imaging measurements was done in a porcine model. The infrared thermocamera Workswell WIC 640 was used in our study. The thermal imaging was correlated with the indocyanine green imaging method ICG NOVADAQ and with surgeon's subjective expert decisions of the places of resection lines. Fifteen monitored resections were performed on three experimental porcine models.ResultsBased on the data evaluated, experience of the surgical team and the post-operative conditions of the porcine models, we conclude that the thermal imaging is a useful tool for determination of the optimal intestinal resection margins, and thus contributes to lowering anastomotic complications rate in colorectal surgery. The results show relatively high consistency between the used imaging techniques. Both methods showed ischemic regions of the intestine at a comparable level. The IRT methods showed even a slightly higher match with the surgeon's rating.ConclusionBased on experiments, the infrared thermography can be considered as one of complementary imaging methods suitable for use during anastomosis surgery. The sensitivity and versatility of the infrared thermography method was demonstrated. There was confirmed agreement in obtained information about the position of area with maximal blood insufficiency obtained by IRT with the information obtained by using the ICG method.     

RNAi suppression of CYP82D P450 hydroxylase,an enzyme involved in gossypol biosynthesis,enhances resistance to Fusarium wilt in cotton

Cotton plants produce two classes of terpenoid defence compounds against pathogens and other pests. Both classes are derived from a common sesquiterpenoid precursor, δ-cadinen-2-one, which enters either the gossypol pathway or the lacinilene pathway. Blocking the gossypol pathway by RNAi suppression of the early pathway biosynthetic enzyme CYP82D hydroxylase resulted in enhanced resistance to the Fusarium wilt pathogen. Analyses of root terpenoids revealed no overall increases in the products of the gossypol pathway in the roots infected by the wilt pathogen. However, the lacinilene pathway was elicited by the pathogen and the lacinilene levels were 19-fold higher in the RNAi plants than in wild-type plants. In the pathogen inoculated RNAi 73R plants, the concentrations of DHC and HMC were 231 μg and 886 μg/g dry roots, respectively, which may have contributed to the inhibition of fungal invasion. In comparison, the concentrations of DHC and HMC in the pathogen inoculated control wild-type 73W plants were only 0.7 μg and 58 μg/g dry roots, respectively. Fungitoxicity testing showed that DHC at 100 μg/ml inhibited growth of the Fusarium wilt pathogen by >93%. Treatment with the phytohormone jasmonic acid failed to elicit production of lacinilene pathway terpenoids in roots of either RNAi plants or their wild-type sibling lines, but increased production of gossypol pathway terpenoids with concentrations in RNAi plants 80%–97% less than those in wild-type plants. This indicates that induction of the lacinilene pathway is not directly mediated by jasmonic acid signalling and requires other signalling to activate the pathway. These results illustrate possible mechanisms of wilt disease resistance in cotton and provide a new approach to increase host resistance by manipulating these two major cotton chemical defence pathways.     

Ploidy effect on the radiation reaction of mammalian cells

Summary The chromatid breaking rate induced in the G2 phase was analyzed for the diploid (B14F28) and the tetraploid (B14F28/117) cell line of chinese hamsters. The breaking rate was proportional to the dose. The tetraploid genome produced about double the number of breaks, i.e. in both substrains the same number of aberrations per chromosome was induced.Cysteamine decreased but BUdR increased the breaking rate of both lines by nearly the same factor, the combination of both substances almost counterbalanced their effects. Comparisons were made of the surviving rates of the cells.     

Diseases of insects and other arthropods: results of diagnostic research over 55 years

Arthropods and especially insects are attacked by many arthropod-pathogenic organisms belonging to viruses, bacteria including rickettsiae, fungi, microsporidia, protists, and nematodes. They may cause lethal or chronic diseases. For 55 years, research on all kinds of arthropod diseases was conducted at the Institute for Biological Control, Darmstadt, formerly belonging to the Federal Biological Research Centre for Agriculture and Forestry (BBA) that became part of the newly founded Julius Kühn-Institute. Special attention is still being paid to diagnostics. During this period, about 1900 accessions comprising many thousands of dead or diseased specimens from 21 different arthropod orders were examined and the causative agents diagnosed. In the present paper, about 450 arthropod species, mainly insects, are listed together with the group and scientific name of the diagnosed arthropod pathogens and the origin (country) of the accession.     

Modeling the Residence Time Distribution of Integrated Continuous Bioprocesses

In response to the biopharmaceutical industry advancing from traditional batch operation to continuous operation, the Food and Drug Administration (FDA) has published a draft for continuous integrated biomanufacturing. This draft outlines the most important rules for establishing continuous integration. One of these rules is a thorough understanding of mass flows in the process. A computer simulation framework is developed for modeling the residence time distribution (RTD) of integrated continuous downstream processes based on a unit‐by‐unit modeling approach in which unit operations are simulated one‐by‐one across the entire processing time, and then combined into an integrated RTD model. The framework allows for easy addition or replacement of new unit operations, as well as quick adjustment of process parameters during evaluation of the RTD model. With this RTD model, the start‐up phase to reach steady state can be accelerated, the effects of process disturbances at any stage of the process can be calculated, and virtual tracking of a section of the inlet material throughout the process is possible. A hypothetical biomanufacturing process for an antibody was chosen for showcasing the RTD modeling approach.