Plastids of Marine Phytoplankton Produce Bioactive Pigments and Lipids

Phytoplankton is acknowledged to be a very diverse source of bioactive molecules. These compounds play physiological roles that allow cells to deal with changes of the environmental constrains. For example, the diversity of light harvesting pigments allows efficient photosynthesis at different depths in the seawater column. Identically, lipid composition of cell membranes can vary according to environmental factors. This, together with the heterogenous evolutionary origin of taxa, makes the chemical diversity of phytoplankton compounds much larger than in terrestrial plants. This contribution is dedicated to pigments and lipids synthesized within or from plastids/photosynthetic membranes. It starts with a short review of cyanobacteria and microalgae phylogeny. Then the bioactivity of pigments and lipids (anti-oxidant, anti-inflammatory, anti-mutagenic, anti-cancer, anti-obesity, anti-allergic activities, and cardio- neuro-, hepato- and photoprotective effects), alone or in combination, is detailed. To increase the cellular production of bioactive compounds, specific culture conditions may be applied (e.g., high light intensity, nitrogen starvation). Regardless of the progress made in blue biotechnologies, the production of bioactive compounds is still limited. However, some examples of large scale production are given, and perspectives are suggested in the final section.     

Description of batter mixing using near infrared spectroscopy

The aim of the present study was to describe the physicochemical events occurring during batter mixing at different water contents (51.8, 54.4, and 56.7 g of water/100 g of dough) using near infrared (NIR) spectroscopy. An FT-NIR spectrometer over the 1000–2500 nm range with a fibre optic probe was used to record NIR spectra in-line. The analysis of both one-dimensional statistical method (principal components analysis) and two-dimensional statistical methods (generalised two-dimensional correlation spectroscopy) was conducted to evaluate the possibilities of NIR spectroscopy to monitor physical and physicochemical modifications observed during mixing of batter. The NIR results were in agreement with the physical and physicochemical analysis traditionally used to study bread dough mixing (consistency and glutenin depolymerisation). PCA on raw NIR spectra demonstrated that PC₁ describes the same traces as the dough consistency curves. PCA on raw NIR spectra can be used to monitor the batter mixing and to identify the NIR mixing time close to the t_peak.PCA on spectra after second derivative demonstrated that PC₁ and PC₂ traces described different traces compared to the dough consistency curves. The loading spectra associated to PC₁ and PC₂ suggested that almost the same physicochemical and chemical mechanisms occur during the dough mixing at 51.8 or 54.4% water contents, but with kinetic and intensity differences. The 2D COS method allowed a sequence of chemical events occurring during mixing for the batters at 51.8 and 54.4% water contents to be tentatively proposed. The 2D COS did not give clear physicochemical differences between the three batters during mixing. The NIR results for the highly hydrated batter (56.7%) were difficult to analyse due to its high water content.     

Comparison of management strategies for controlling Nassella trichotoma in modified tussock grasslands in New Zealand: a spatial and economic analysis

The weedy grass Nassella trichotoma (nassella tussock), historically an economically damaging invader of modified tussock grasslands in New Zealand, currently causes little if any reduction in farm production. This is a result of successful historical regional management programmes in which plants have been removed manually (by grubbing) each year before they seed. To inform a debate about the need for ongoing regional management, we developed a stage‐structured spatially explicit integrodifference equation population model and linked this to a cost analysis. We used the model to compare the weed's future population trajectories and related regional control costs over 50 years under three alternative management scenarios. The total discounted (3% p.a.) costs of no management, three‐yearly grubbing and continued annual grubbing were NZ $417 million, $736 million and $131 million respectively. These analyses indicate that annual grubbing of N. trichotoma returns a net benefit of $286 million ($417 – $131 million) compared with doing nothing and a net benefit of $605 million ($736 – $131 million) compared with a 3‐yearly grubbing programme. These results support the continuation of annual grubbing as the long‐term economically optimal management strategy for N. trichotoma on pastoral farms infested by the weed in New Zealand.     

The impact of management on weeds and aquatic plant communities in Hungarian rice crops

This study assessed the cultural and weed management factors influencing the weed communities of Hungarian rice fields. Hungary is situated at the northern limit of rice production with a history of about 300 years of rice culture. We surveyed the weed flora and 25 background variables in 100 active rice fields. Using a minimal adequate model containing 11 terms, 48.5% of the total variation in weed species data could be explained. The net effects of nine variables on species composition were significant. Crop cover was found to be the most important explanatory variable, which was followed by the herbicides penoxsulam and azimsulfuron, tillage depth, phosphorous and potassium fertilisers, years after last rotation, water depth in May, sowing type, pendimethalin and water conductivity. Filamentous algae, as the most abundant group of weeds, were positively associated with deep tillage, deep water and surface sowing. Echinochloa crus‐galli, one of the most troublesome grass weeds, was associated with low rice cover, shallow water and later years after crop rotation, while weedy rice favoured high crop cover, deep water and soil sowing. These findings can be used to design improved weed management strategies. The occurrence of red list species and charophytes in diverse micro‐mosaic patterns deserves attention from a conservation perspective, as well. The maintenance of these unique charophyte communities can be facilitated by shallow tillage without soil inversion.     

Predicting and mitigating the net greenhouse gas emissions of crop rotations in Western Europe

Nitrous oxide, carbon dioxide and methane are the main biogenic greenhouse gases (GHGs) contributing to net greenhouse gas balance of agro-ecosystems. Evaluating the impact of agriculture on climate thus requires capacity to predict the net exchanges of these gases in a systemic approach, as related to environmental conditions and crop management. Here, we used experimental data sets from intensively monitored cropping systems in France and Germany to calibrate and evaluate the ability of the biophysical crop model CERES-EGC to simulate GHG exchanges at the plot-scale. The experiments involved major crop types (maize-wheat-barley-rapeseed) on loam and rendzina soils. The model was subsequently extrapolated to predict CO₂ and N₂O fluxes over entire crop rotations. Indirect emissions (IE) arising from the production of agricultural inputs and from use of farm machinery were also added to the final greenhouse gas balance. One experimental site (involving a maize-wheat-barley-mustard rotation on a loamy soil) was a net source of GHG with a net GHG balance of 670 kg CO₂-C eq ha⁻¹ yr⁻¹, of which half were due to IE and half to direct N₂O emissions. The other site (involving a rapeseed-wheat-barley rotation on a rendzina) was a net sink of GHG for −650 kg CO₂-C eq ha⁻¹ yr⁻¹, mainly due to high C returns to soil from crop residues. A selection of mitigation options were tested at one experimental site, of which straw return to soils emerged as the most efficient to reduce the net GHG balance of the crop rotation, with a 35% abatement. Halving the rate of N inputs only allowed a 27% reduction in net GHG balance. Removing the organic fertilizer application led to a substantial loss of C for the entire crop rotation that was not compensated by a significant decrease of N₂O emissions due to a lower N supply in the system. Agro-ecosystem modeling and scenario analysis may therefore contribute to design productive cropping systems with low GHG emissions.     

Autumnal changes of sulfur fractions and the ratio of organic sulfur to total nitrogen in leaves and adjacent bark of eastern cottonwood, white basswood and actinorhizal black alder

Autumnal changes in organic-S, sulfate-S, total-S and the ratios of organic-S to total-N and sulfate-S to organic-S were followed in leaves and adjacent bark of actinorhizal (Frankia-nodulated) black alder (Alnus glutinosa (L.) Gaertn.) and eastern cottonwood (Populus deltoides Bartr. ex Marsh.) trees growing on a minespoil site high in extractable soil sulfate, and in black alder and white basswood (Tilia heterophylla Venten.) trees growing on a prairie-derived soil in Illinois. Organic-S concentrations decreased significantly (P < 0.05) during autumn only in foliage of trees growing on the prairie-derived soil where losses of leaf organic-S were 65% for black alder and 100% for white basswood. Leaf sulfate concentrations were relatively stable throughout autumn in white basswood growing on prairie-derived soil and in black alder at both sites. Sulfate-S concentrations in leaves were significantly (P < 0.05) higher in trees at the minespoil site than in trees growing in the prairie-derived soil (5.1 mg g(-1) for the minespoil site and 1.2 mg g(-1) for the prairie-derived soil), and in the non-actinorhizal species during late summer. During the autumn, the ratio of organic-S to total-N doubled in leaves of eastern cottonwood at the minespoil site, but in black alder and white basswood growing on the prarie-derived soil, it decreased by 60 and 74%, respectively. Organic-S concentrations in bark increased more during autumn in species unable to fix atmospheric N(2), than in black alder. The results suggest that patterns of autumnal translocation of leaf S can be site-dependent and that leaf S and leaf N are, at least in part, translocated independently in the fall. Black alder and eastern cottonwood seemed to incorporate sulfate-S readily into organic substances in leaves when grown in soils with a high sulfate content.     

Ultrastructure—Critical domain for wood behavior

Summary That the behavior of wood in service results from its structure is generally accepted by wood scientists. No doubt this acceptance is due to the broad interpretation of such a term. Structure can refer to the organization of elements on a macro scale, such as in a laminated beam, as well as to the arrangement of cellulose molecules in the crystalline region of an elementary fibril.This presentation focuses on a structural domain that appears increasingly to be a critical one in wood behavior-ultrastructure. The spectrum of terminology that has been used in profusion during the electron microscopic era must first be defined so that confusion is minimized. Then a historical evolution of the field of wood ultrastructure can be presented to provide perspective. Structures that have been shown to affect or indeed to control certain processes can be identified. The role of a non-structure, the elusive transient capillary, can be illustrated. Microfibrillar organization and cell wall archictecture fall into the realm of ultrastructure as well.The past decade of research in wood science has been productive to a significant extent because of scanning electron microscopy and its accessory tools and techniques. The exploration of wood penetration by wood preservatives, pulping liquors and coatings using this approach has yielded much new evidence. One can speculate about the anticipated contributions of computer-driven SEM, stereology, STEM, and even higher resolution microscopy in the near future.     

Factors affecting permeability and pit aspiration in coniferous sapwood

Summary The influence of drying methods on the permeability of red pine and eastern hemlock sapwood was investigated. Permeability was found to be reduced by normal drying procedures to only a small percentage of the green permeability. The reduction was more severe at higher drying temperatures; less severe but still very large at -18° C. Pit aspiration was shown to be responsible for the reduction. Replacing the sap with surfactant solutions and organic liquids and evaporating them revealed that pit aspiration occurred with surfactant solutions having surface tension values of less than 20 dynes/cm and did not occur with organic liquids having surface tension values as high as 44 dynes/cm. It is suggested that a critical factor in pit aspiration is the adhesion of the torus to the pit border, and the failure of the organic liquids to cause pit aspiration is due to their inability to promote adhesion between the torus and pit border.

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Zusammenfassung Der Einfluß verschiedener Trocknungsverfahren auf die Durchlässigkeit des Splintholzes bei Kiefer und Eastern Hemlock wurde untersucht. Es zeigte sich, daß bei Anwendung üblicher Trocknungsverfahren die Durchlässigkeit gegenüber jener des frischen Holzes sehr deutlich vermindert war. Höhere Trocknungstemperaturen setzten die Durchlässigkeit weit stärker herab; bei -18° C war die Verminderung etwas weniger stark, jedoch noch immer beträchtlich. Als Ursache für die Durchlässigkeitsverminderung wurde der Tüpfelverschluß gefunden. Beim Austausch des Zellsaftes gegen oberflächenaktive Lösungen bzw. gegen organische Flüssigkeiten und bei nachfolgender Verdampfung derselben ergab sich, daß die oberflächenaktiven Lösungen mit Oberflächenspannungswerten von höchstens 20 dyn/cm einen Tüpfelverschluß erzeugten, die organischen Lösungen mit Oberflächenspannungswerten bis zu 44 dyn/cm jedoch nicht. Es wird postuliert, daß beim Tüpfelverschluß das Haften des Torus am Tüpfelrand das Kriterium bildet; die Unfähigkeit bestimmter organischer Lösungen, einen Tüpfelverschluß zu bilden, ist darin zu sehen, daß sie die Adhäsion zwischen dem Torus und dem Tüpfelrand nicht zu fördern vermögen.

     

Use of computed tomography angiography for the evaluation of a cutaneous haemangioma in a Standardbred horse

Cutaneous haeangiomas are benign vascular neoplasms that arise from endothelial cells of blood vessels. Haemangiomas account for 0.6%–4% of all equine cutaneous neoplasms and the fetlock is the most commonly affected site. We describe the use of computed tomography angiography (CTA) for the evaluation of a cutaneous haemangioma located on the plantarolateral aspect of the left hindlimb fetlock of a 9-month-old Standardbred colt. Computed tomography angiography of the affected fetlock was performed under general anaesthesia. The medial plantar artery was catheterised and a total volume of 50 ml of iodinated non-ionic contrast medium (Iopamidol, 300 mg I/ml, Bracco Imaging Canada) was injected at a rate of 2 ml/s. Following contrast medium administration, the dorsal metatarsal artery and branches including the lateral and medial digital arteries were well demarcated. Two smaller lateral and medial arteries were also identified, forming the vascular network of the metatarsophalangeal joint. At the level of the haemangioma, two tortuous arteries arising from the lateral digital artery were identified, in addition to multiple small branches from nearby cutaneous arteries. These vessels supplied the homogeneously strongly contrast-enhancing cutaneous mass. The initial goal of the CTA study was to map the vascular anatomy for arterial embolisation in conjunction with pharmacological therapy. Considering the involvement of multiple small arterial branches, complete surgical excision along with ligation of the two main supplying arteries was alternatively elected, resulting in a successful long-term outcome.