Remote, subsurface detection of the algal toxin domoic acid onboard the Environmental Sample Processor: Assay development and field trials

The ability to detect harmful algal bloom (HAB) species and their toxins in real- or near real-time is a critical need for researchers studying HAB/toxin dynamics, as well as for coastal resource managers charged with monitoring bloom populations in order to mitigate their wide ranging impacts. The Environmental Sample Processor (ESP), a robotic electromechanical/fluidic system, was developed for the autonomous, subsurface application of molecular diagnostic tests and has successfully detected several HAB species using DNA probe arrays during field deployments. Since toxin production and thus the potential for public health and ecosystem effects varies considerably in natural phytoplankton populations, the concurrent detection of HAB species and their toxins onboard the ESP is essential. We describe herein the development of methods for extracting the algal toxin domoic acid (DA) from Pseudonitzschia cells (extraction efficiency >90%) and testing of samples using a competitive ELISA onboard the ESP. The assay detection limit is in the low ng/mL range (in extract), which corresponds to low ng/L levels of DA in seawater for a 0.5 L sample volume acquired by the ESP. We also report the first in situ detection of both a HAB organism (i.e., Pseudo-nitzschia) and its toxin, domoic acid, via the sequential (within 2-3 h) conduct of species- and toxin-specific assays during ESP deployments in Monterey Bay, CA, USA. Efforts are now underway to further refine the assay and conduct additional calibration exercises with the aim of obtaining more reliable, accurate estimates of bloom toxicity and thus their potential impacts. Published by Elsevier B.V.

Computer simulations of seasonal outbreak and diurnal vertical migration of cyanobacteria

Algal blooms caused by cyanobacteria are characterized by two features with different time scales: one is seasonal outbreak and collapse of a bloom and the other is diurnal vertical migration. Our two-component mathematical model can simulate both phenomena, in which the state variables are nutrients and cyanobacteria. The model is a set of one-dimensional reaction-advection-diffusion equations, and temporal changes of these two variables are regulated by the following five factors: (1) annual variation of light intensity, (2) diurnal variation of light intensity, (3) annual variation of water temperature, (4) thermal stratification within a water column and (5) the buoyancy regulation mechanism. The seasonal change of cyanobacteria biomass is mainly controlled by factors, (1), (3) and (4), among which annual variations of light intensity and water temperature directly affect the maximum growth rate of cyanobacteria. The latter also contributes to formation of the thermocline during the summer season. Thermal stratification causes a reduction in vertical diffusion and largely prevents mixing of both nutrients and cyanobacteria between the epilimnion and the hypolimnion. Meanwhile, the other two factors, (2) and (5), play a significant role in diurnal vertical migration of cyanobacteria. A key mechanism of vertical migration is buoyancy regulation due to gas-vesicle synthesis and ballast formation, by which a quick reversal between floating and sinking becomes possible within a water column. The mechanism of bloom formation controlled by these five factors is integrated into the one-dimensional model consisting of two reaction-advection-diffusion equations.

Combining bio- and chemo-catalysis: from enzymes to cells, from petroleum to biomass

In the future, biomass will continue to emerge as a viable source of chemicals. The development of new industries that utilize bio-renewables provides opportunities for innovation. For example, bio- and chemo-catalysts can be combined in 'one pot' to prepare chemicals of commercial value. This has been demonstrated using isolated enzymes and whole cells for a variety of chemical transformations. The one-pot approach has been successfully adopted to convert chemicals derived from biomass, and, in our opinion, it has an important role to play in the design of a more sustainable chemical industry. To implement new one-pot bio- and chemo-catalytic processes, issues of incompatibility must be overcome; the strategies for which are discussed in this opinion article.

An in vitro Study to Assess the Potential of a Unique Micro porous Algal Derived Cap Bone Void Filler in Comparison with Clinically-Used Bone Void Fillers

Macroporosity(>100µm) in bone void fillers is a known prerequisite for tissue regeneration, but recent literature has highlighted the added benefit of microporosity(0.5 - 10µm). The aim of this study was to compare the in vitro performances of a novel interconnective microporous hydroxyapatite (HA) derived from red algae to four clinically available macroporous calcium phosphate (CaP) bone void fillers. The use of algae as a starting material for this novel void filler overcomes the issue of sustainability, which overshadows continued use of scleractinian coral in the production of some commercially available materials, namely Pro-OsteonTM and Bio-Coral®. This study investigated the physicochemical properties of each bone voidfiller material using x-ray diffraction, fourier transform infrared spectroscopy, inductive coupled plasma, and nitrogen gas absorption and mercury porosimetry. Biochemical analysis, XTT, picogreen and alkaline phosphatase assays were used to evaluate the biological performances of the five materials. Results showed that algal HA is non-toxic to human foetal osteoblast (hFOB) cells and supports cell proliferation and differentiation. The preliminary in vitro testing of microporous algal-HA suggests that it is comparable to the four clinically approved macroporous bone void fillers tested. The results demonstrate that microporous algal HA has good potential for use in vivo and in new tissue engineered strategies for hard tissue repair.

NUCLEAR STAINING IN ALGAL HERBARIUM MATERIAL - A REAPPRAISAL OF THE HOLOTYPE OF CALLITHAMNION-DECOMPOSITUM AGARDH,J. (RHODOPHYTA)

The taxonomic importance of uninucleate vs. multinucleate vegetative cells in the Ceramiaceae is emphasized. It has been possible to make visible nuclei in old material, including type specimens, using aceto-carmine and aceto-iron-haematoxylin stains. The holotypes of Ceramium roseum and Callithamnion fasciculatum (currently known as Callithamnion roseum and Pleonosporium borreri var. fasciculatum) have uninucleate cells and belong to Aglaothamnion. In contrast, the holotype of Callithamnion decompositum, a name that has been applied to collections of at least two uninucleate taxa, has multinucleate cells; its morphological and cytological details agree with those of specimens collected in France and Ireland that were previously thought to represent an undescribed species. Female reproductive morphology (described from a thallus with gametangia in addition to tetrasporangia), in conjunction with habit and vegetative features, indicates that this species belongs to Compsothamnion (Compsothamnieae), as a third species, being distinguished from C. thuyoides and C. gracillimum by its sessile, lateral tetrasporangia. The required new combinations under Aglaothamnion and Compsothamnion are made.

PLASTID DNA RESTRICTION ANALYSIS LINKS THE HETEROMORPHIC PHASES OF AN APOMICTIC RED ALGAL LIFE-HISTORY

Gymnogongrus sp. (Phyllophoraceae) from Nova Scotia, Canada, identified tentatively as G. devoniensis (Greville) Schotter, grows in association with an Erythrodermis-like crust that forms chains of tetrasporangia or bisporangia. The crust resembles tetrasporophytic phases of other Gymnogongrus species, but in culture both it and the G. ?devoniensis gametophytes cycle independently by apomictic reproduction.

Reproductive biomass in Holcus lanatus clones that differ in their phosphate uptake kinetics and mycorrhizal colonization

In normal populations of the common grass Holcus lanatus there is a polymorphism for arsenate resistance, manifested as suppressed phosphate uptake (SPU), and controlled by a major gene with dominant expression. A natural population of SPU plants had greater arbuscular-mycorrhizal colonization than wild type, nonSPU plants. It was hypothesized that, in order to survive alongside plants with a normal rate of phosphate (P) uptake, SPU plants would be more dependent on mycorrhizal associations. We performed an experiment using plants with SPU phenotypes from both arsenate mine spoils and uncontaminated soils, as well as plants with a nonSPU phenotype. They were grown with and without a mycorrhizal inoculum and added N, which altered plant P requirements. We showed that grasses with SPU phenotypes accumulated more shoot P than nonSPU plants, the opposite of the expected result. SPY plants also produced considerably more flower panicles, and had greater shoot and root biomass. The persistence of SPU phenotypes in normal populations is not necessarily related to mycorrhizal colonization as there were no differences in percentage AM colonization between the phenotypes. Being mycorrhizal reduced flower biomass production, as mycorrhizal SPU plants had lower shoot P concentrations and produced fewer flower panicles than non-mycorrhizal, nonSPU plants. We now hypothesize that the SPU phenotype is brought about by a genotype that results in increased accumulation of P in shoots, and that suppression of the rate of uptake is a consequence of this high shoot P concentration, operating by means of a homeostatic feedback mechanism. We also postulate that increased flower production is linked to a high shoot P concentration. SPU plants thus allocate more resources into seed production, leading to a higher frequency of SPU genes. Increased reproductive allocation reduces vegetative allocation and may affect competitive ability and hence survival, explaining the maintenance of the polymorphism. As mycorrhizal SPU plants behave more like nonSPU plants, AM colonization itself could play a major part in the maintenance of the SPU polymorphism.

Flux and turnover of fixed carbon in soil microbial biomass of limed and unlimed plots of an upland grassland ecosystem

The influence of liming on rhizosphere microbial biomass C and incorporation of root exudates was studied in the field by in situ pulse labelling of temperate grassland vegetation with (13)CO(2) for a 3-day period. In plots that had been limed (CaCO(3) amended) annually for 3 years, incorporation into shoots and roots was, respectively, greater and lower than in unlimed plots. Analysis of chloroform-labile C demonstrated lower levels of (13)C incorporation into microbial biomass in limed soils compared to unlimed soils. The turnover of the recently assimilated (13)C compounds was faster in microbial biomass from limed than that from unlimed soils, suggesting that liming increases incorporation by microbial communities of root exudates. An exponential decay model of (13)C in total microbial biomass in limed soils indicated that the half-life of the tracer within this carbon pool was 4.7 days. Results are presented and discussed in relation to the absolute values of (13)C fixed and allocated within the plant-soil system.

Hydrolysis characteristics and kinetics of waste hay biomass as a potential energy crop for fermentable sugars production using autoclave parr reactor system

The use of the organic fraction of municipal solid waste crops has received considerable attention as a sustainable feedstock that can replace fossil fuels for the production of renewable energy. Therefore, municipal bin-waste in the form of hay was investigated as a potential energy crop for fermentable sugars production. Hydrolysis of hay by dilute phosphoric acid was carried out in autoclave parr reactor, where reactor temperature (135-200 degrees c) and acid concentration (2.5-10% (w/w)) were examined. Analysis of the decomposition rate of hemicellulosic biomass was undertaken using HPLC of the reaction products. Xylose production reached a maximum value of 13.5 g/100 g dry mass corresponding to a yield of 67% at the best identified conditions of 2.5 wt% H3PO4, 175 degrees C, 10 min reaction time, and at 5 wt% H3PO4, 150 degrees C, and 5 min reaction time. For glucose, an average yield of 25% was obtained at 5 wt% H3PO4, 175 degrees C and 30 min. Glucose degradation to HMF was achieved at 10 wt% H3PO4 and 200 degrees C. The maximum yield for produced arabinose was an average of 3 g/100 g dry. mass corresponding to 100% of the total possible arabinose. The kinetic study of the acid hydrolysis was also carried out using the Saeman and the Two-fraction models. It was found for both models that the kinetic constants (k) depend on the acid concentration and temperature. For xylose and arabinose it was found that the rate of formation was more favoured than the rate of degradation. By contrast, for glucose it was found that glucose degradation was occurring faster than glucose formation. It can be concluded that dilute phosphoric acid hydrolysis of hay crop is feasible for the production of fermentable sugars which are essential for bioethanol synthesis. 

Coleoptera and microbe biomass in Antarctic Dry Valley paleosols adjacent to the Inland Ice: Implications for Mars

Bulk paleosol samples collected from a Middle to Early Miocene moraine in the New Mountain area of the Dry Valleys, Antarctica, yielded Coleoptera exoskeletons and occasional endoskeletons showing considerable diagenetic effects along with several species of bacteria, all lodged in a dry-frozen but salt-rich horizon at shallow depth to the land surface. The till is at the older end of a chronologic sequence of glacial deposits, thought to have been deposited before the transition from wet-based to cold-based ice (similar to 15 Ma), and hence, entirely weathered in contact with the subaerial atmosphere. It is possible, though not absolutely verifiable, that the skeletons date from this early stage of emplacement having undergone modifications whenever light snowmelt occurred or salt concentrations lowered the freezing temperature to maintain water as liquid. Correlation of the Coleoptera species with cultured bacteria in the sample and the likelihood of co-habitation with Beauveria bassiani found in two adjacent, although younger paleosols, leads to new questions about the antiquity of the Coleoptera and the source of N and glucose from chitinase derived from the insects. The skeletons in the 831 section may date close to the oldest preserved chitin (Oligocene) yet found on Earth. While harsh Martian conditions make it seemingly intolerable for complex, multicellular organisms such as insects to exist in the near-surface and subaerially, life within similar cold, dry paleosol microenvironments (Cryosols) of Antarctica point to life potential for the Red Planet, especially when considering the relatively diverse microbe (bacteria and fungi) population. (C) 2011 Elsevier Ltd. All rights reserved.

New methods in Biomass Depolymerisation: Catalytic Hydrogenolysis of Barks

Hydrogenolysis of bark from three different species of tree using heterogeneous platinum group metal catalysts produces two major product streams. Aromatic substituted guaiacols are produced from lignin and the lignin-like regions of suberin and a range of saturated fatty acids and alcohols, including a,?-functionalised species, are produced from the polyester regions of suberin. Control experiments demonstrate clear advantages of catalytic hydrogenolysis over base hydrolysis, both in terms of conversion and product selectivity.

A balanced polymorphism in biomass resource allocation controlled by phosphate in grasses screened through arsenate tolerance

The response of arsenate and non-tolerant Holcus lanatus L. phenotypes, where tolerance is achieved through suppression of high affinity phosphate/arsenate root uptake, was investigated under different growth regimes to investigate why there is a polymorphism in tolerance found in populations growing on uncontaminated soil. Tolerant plants screened from an arsenic uncontaminated population differed, when grown on the soil from the populations origin, from non-tolerants, in their biomass allocation under phosphate fertilization: non-tolerants put more resources into tiller production and down regulated investment in root production under phosphate fertilization while tolerants tillered less effectively and did not alter resource allocation to shoot biomass under phosphate fertilization. The two phenotypes also differed in their shoot mineral status having higher concentrations of copper, cadmium, lead and manganese, but phosphorus status differed little, suggesting tight homeostasis. The polymorphism was also widely present (40%) in other wild grass species suggesting an important ecological role for this gene that can be screened through plant root response to arsenate.