Overall development of a bioprocess for the outdoor production of Nannochloropsis gaditana for aquaculture

In this paper, a systematic methodology is shown for the scaling‐up of Nannochloropsis gaditana production for aquaculture uses. First, an adequate culture medium was developed, prepared using fertilizers instead of pure chemicals. Subsequently, the performance of N. gaditana was modelled as a function of average irradiance; this model being validated in continuous culture experiments. The model was used to determine the optimal dilution rate as well as the expected biomass concentration and productivity at optimal conditions. Finally, outdoor experiments were performed to confirm the model's validity and to determine optimal conditions at real production step. Biomass productivity values of up to 0.08 g L^?1 day^?1 were obtained at an optimal dilution rate of 0.25 per day in 0.2 m wide flat‐panel reactors using culture medium containing 0.4 g/L NO^?₃ and 0.034 g/L·PO₄^?3. Fish trials with Atlantic Salmon demonstrated that the inclusion of produced biomass into fed increase the final weight up to 5%, thus confirming the adequacy of the biomass produced for aquaculture uses. The growth model and the scaling‐up strategy proposed here are necessary to develop real industrial‐scale processes capable of supplying microalgal biomass to the aquaculture markets, which in turn require a guaranteed supply and quality of the raw materials provided.     

Plant Host Range of Verticillium longisporum and Microsclerotia Density in Swedish Soils

Verticillium longisporum is a soil-borne fungal pathogen causing vascular wilt of Brassica crops. This study was conducted to enhance our knowledge on the host range of V. longisporum. Seven crop species (barley, oat, oilseed rape, pea, red clover, sugar beet and wheat) and five weed species (barren brome, black-grass, charlock, cleavers and scentless mayweed) all common in southern Sweden were evaluated for infection by response to V. longisporum. Oat, spring wheat, oilseed rape, scentless mayweed and charlock inoculated with V. longisporum in a greenhouse showed stunting to various degrees close to the fully ripe stage. Based on the extent of microsclerotia formation, explants were separated into four groups: for pea and wheat, <5% of the samples had formed microsclerotia; for scentless mayweed, 5–10%; for oat, 10–20%; and for charlock and oilseed rape >80%. The results suggest that plant species outside the Brassicaceae can act as reservoirs of V. longisporum inoculum. Soil inoculum densities in nine fields were monitored over a period of 12 months, which ranged from 1 to 48 cfu g⁻¹ soil. Density of microsclerotia was lowest just after harvest, reaching its maximum six months later. No significant correlation between inoculum density in soil and disease incidence on oilseed rape plants was found. However, the data suggest that a threshold of 1 cfu g⁻¹ soil is needed to cause disease on oilseed rape. Species identification based on microsclerotia morphology and PCR analysis showed that V. longisporum dominated in soil of seven, and V. dahliae in two of the nine fields studied.     

Biological indicators for evaluating soil quality improvement in a soil degraded by erosion processes

Journal of Soils and Sediments - Erosion is one of the main soil degradation problems. It diminishes soil biological activity and therefore its quality. The aim of the study was to evaluate if the...     

Dissolved and colloidal phosphorus fluxes in forest ecosystems—an almost blind spot in ecosystem research

Understanding and quantification of phosphorus (P) fluxes are key requirements for predictions of future forest ecosystems changes as well as for transferring lessons learned from natural ecosystems to croplands and plantations. This review summarizes and evaluates the recent knowledge on mechanisms, magnitude, and relevance by which dissolved and colloidal inorganic and organic P forms can be translocated within or exported from forest ecosystems. Attention is paid to hydrological pathways of P losses at the soil profile and landscape scales, and the subsequent influence of P on aquatic ecosystems. New (unpublished) data from the German Priority Program 1685 “Ecosystem Nutrition: Forest Strategies for limited Phosphorus Resources” were added to provide up‐to‐date flux‐based information. Nitrogen (N) additions increase the release of water‐transportable P forms. Most P found in percolates and pore waters belongs to the so‐called dissolved organic P (DOP) fractions, rich in orthophosphate‐monoesters and also containing some orthophosphate‐diesters. Total solution P concentrations range from ca. 1 to 400 µg P L^?1, with large variations among forest stands. Recent sophisticated analyses revealed that large portions of the DOP in forest stream water can comprise natural nanoparticles and fine colloids which under extreme conditions may account for 40–100% of the P losses. Their translocation within preferential flow passes may be rapid, mediated by storm events. The potential total P loss through leaching into subsoils and with streams was found to be less than 50 mg P m^?2 a^?1, suggesting effects on ecosystems at centennial to millennium scale. All current data are based on selected snapshots only. Quantitative measurements of P fluxes in temperate forest systems are nearly absent in the literature, probably due to main research focus on the C and N cycles. Therefore, we lack complete ecosystem‐based assessments of dissolved and colloidal P fluxes within and from temperate forest systems.     

Cover crop and plant density in seed production of white clover (Trifolium repens L.)

Seed crops of white clover (Trifolium repens L.) are usually established with a cover crop. Provided sufficient light, white clover may compensate for low plant density by stoloniferous growth. Our objectives were (1) to compare spring barley or spring wheat used as cover crops for white clover and (2) to find the optimal seeding rate/row distance for white clover. Seven field trials were conducted in Southeast Norway from 2000 to 2003. Barley was seeded at 360 and 240 seeds m^?2 and wheat at 525 and 350 seeds m^?2. White clover was seeded perpendicularly to the cover crop at 400 seeds m^?2/13 cm row distance or 200 seeds m^?2/26 cm. Results showed that light penetration in spring and early summer was better in wheat than in barley. On average for seven trials, this resulted in 11% higher seed yield after establishment in wheat than in barley. The 33% reduction in cover crop seeding rate had no effect on white clover seed yield for any of the cover crops. Reducing the seeding rate/doubling the row distance of white clover had no effect on seed yield but resulted in slightly earlier maturation of the seed crop.     

Honey as the Potential Natural Source of Cholinesterase Inhibitors in Alzheimer’s Disease

Plant Foods for Human Nutrition - Alzheimer’s disease (AD) is a progressive neurodegenerative disease characterized, among others by abnormal levels of acetyl- and butyrylcholinesterase in...     

Surveys on Coxiella burnetii infections in Swedish cattle,sheep, goats and moose

Background

Q fever is a zoonotic disease caused by the bacterium Coxiella burnetii. Prevalence data in ruminant species are important to support risk assessments regarding public and animal health. The aim was to investigate the presence of or exposure to C. burnetii in cattle, sheep, goats and moose, and to compare two enzyme-linked immunosorbent assays (ELISAs). National surveys of antibodies against C. burnetii were performed for dairy cattle (n=1537), dairy goats (n=58) and sheep (n=518). Bovine samples consisted of bulk milk, caprine of pooled milk, and ovine of pooled serum. Antibodies were investigated in moose samples (n=99) from three regions. A one-year regional cattle bulk milk survey was performed on the Isle of Gotland (n=119, four occasions). Cattle, sheep and goat samples were analysed with indirect ELISA and moose samples with complement fixation test. For the sheep, goat, and parts of the cattle survey, samples were run in parallel by ELISAs based on antigens from infected ruminants and ticks. Bulk milk samples from the regional cattle survey and vaginal swabs from a subset of the sheep herds (n=80) were analysed for the agent by polymerase chain reaction. Spatial clustering was investigated in the national cattle survey.

Results

The prevalence of antibodies in dairy herds was 8.2% with large regional differences. High risk clusters were identified in the southern regions. The prevalence among dairy herds on the Isle of Gotland varied from 55.9% to 64.6% and 46.4% to 58.9.0% for antibodies and agent, respectively, overall agreement between agent and antibodies was 85.2%. The prevalence of antibodies in sheep was 0.6%, the agent was not detected the vaginal swabs. Antibodies were not detected in goats or moose, although parts of the moose samples were collected in an area with high prevalence in cattle. The overall agreement between the two ELISAs was 90.4%.

Conclusions

The prevalence of antibodies against C. burnetii in dairy cattle in Sweden shows large regional differences. The results suggest that C. burnetii is a rare pathogen among Swedish moose, dairy goat and sheep. ELISAs based on ruminant and tick antigen performed in a similar manner under Swedish conditions.     

Flow cytometric patterns in blood from dogs with non-neoplastic and neoplastic hematologic diseases using double labeling for CD18 and CD45

BACKGROUND: In dogs, flow cytometry is used in the phenotyping of immunologic cells and in the diagnosis of hemic neoplasia. However, the paucity of specific antibodies for myeloid cells and B lymphocytes and of labeled antibodies for multicolor techniques limits the ability to detect all leukocyte subpopulations. This is especially true for neoplastic and precursor cells. CD18 and CD45 are expressed on all leukocytes and are involved in cell activation, and together could be useful in helping determine cell lineage. OBJECTIVES: The purpose of this study was to double label canine blood for CD18 and CD45 and to use the differential expression of antigens to identify leukocyte populations in dogs with non-neoplastic and neoplastic hematologic diseases. METHODS: A template was developed using blood samples from 10 clinically healthy dogs and a back-gating technique. Differential leukocyte counts obtained with the template were compared with those obtained by manual and automated methods on blood samples from 17 additional healthy dogs. Blood samples obtained from 9 dogs with non-neoplastic (reactive) hematologic diseases and 27 dogs with hemic neoplasia were double stained for CD18 and CD45 using mouse anticanine CD18 monoclonal antibody (mAb) plus phycoerythrin-conjugated rat anticanine CD45 mAb and fluorescein isothiocyanate-conjugated rabbit antimouse IgG. Hemic neoplasms were diagnosed by cell morphology, and immunophenotypic and cytochemical markers. RESULTS: With the double label, neutrophils, eosinophils, monocytes, and T- and B-lymphocytes were identified. In reactive disorders, a population of activated neutrophils with high CD45 and CD18 expression was detected. In hemic neoplasia, cell lineage was easily determined, even in acute leukemia. CONCLUSIONS: Double labeling for CD18/CD45 may be useful as a screening method to evaluate hematologic diseases and help determine cell lineage, and to aid in the selection of a panel of antibodies that would be useful for further analysis.