303 research outputs found
Limited influence of nutrient additions to the transformation of dissolved and particulate organic matter from a peatland headwater
Peatlands are typically rich in labile dissolved and particulate organic matter (DOM and POM) but poor in nutrients; as these peatland waters flow through a catchment they mix with more nutrient-rich but organic matter (OM) poor waters. These new sources of nutrients may lead to increased OM degradation, driving further release of CO2 to the atmosphere. The aim of this study was to discover if the addition of nutrients changed the rates of peat-derived dissolved and particulate organic carbon (DOC and POC) degradation, or if the additional nutrients were incorporated into the OM structure. The DOM and POM extracted from a peatland stream was characterised at the beginning of the experiment, and after 70-h and 10-days, from water with and without additional nutrients. Results showed adding nutrients to the water had no significant impact on the rate of degradation of DOC or POC over a 10 day period. There were significant differences in the N content and C:N ratios, as well as other composition variables, of the DOM in the treatments with additional nutrients showing that N was incorporated into the DOM structure, but that nutrient addition did not stimulate significant extra DOM or DOC loss. The N content of POM was not impacted, and isotope analysis, supported the conclusion that DOM turnover was occurring even if there was no net change in DOC concentration due to nutrient addition
Implementation of GIS-Based Applications in Water Governance
__Abstract__
Geographical Information Systems (GIS) are computer programs that are able to
bring large amounts of data of both the physical and the social system together in one
comprehensive overview shown digitally. GIS occurred very rapidly on the Dutch policy
agenda. In this paper we analyze how the fast introduction process of GIS-based
instruments in water management and more specifically in river flood management can
be explained. By applying a range of classical models on agenda-setting, we show the
important contribution of GIS to the water and flood issue in current spatial planning and
policy development in the Netherland
Blueberry Advisory Committee Research Report
The 1984 edition of the Blueberry Progress Reports was prepared for the Maine Blueberry Commission and the University of Maine Blueberry Advisory Committee by researchers with the Maine Agricultural Experiment Station and Maine Cooperative Extension Service at the University of Maine, Orono. Projects in this report include:
1. Control, biology, and ecology of insects affecting lowbush blueberries .
2. Chemical control of mummyberry disease (Monilinia vaccinii-corymbosi)
3. New Fungicides for control of Botrytis blossom blight
4. Nutritional survey of selected lowbush blueberry fields
5. Interaction of fertility and pruning practices on soil characteristics and lowbush blueberry growth and yield
6. Long term effects of N and NPK fertilizer on plant growth and yield
7. The effect of N fertilization on clonal spread
8. Nutritional responses of the lowbush blueberry in new plantings as related to early establishment
9. The effect of several mulches on frost heaving, soil moisture, soil temperature and rhizome development
10. Effectiveness of mulches and planted lowbush blueberry seedlings for stabilizing soils and increasing plant cover
11. Effect of surface mulches on stabilizing lowbush blueberry soil in barren areas
12. Frequency of fertility application for establishment of lowbush blueberry seedlings
13. Slow release vs liquid fertilizer for establishment of lowbush blueberry seedlings
14. Comparison of rooted cuttings and tissue culture propagated lowbush blueberry plants
15. The effect of growth regulator formulations on growth and rhizome production of the lowbush blueberry
16. Unburned, mowed fields
17. Blueberry concentrate
18. Blueberry product development
19. Dehydrated blueberries
20. Low-calorie blueberry jellies
21. Hexazinone and terbacil mixture for weed control
22. Hexazinone and atrazine mixture for weed control
23. Effect of hexazinone and nitrogen or nitrogen-phosphorus fertilizer on lowbush blueberry plants
24. Hand-wiper applications of herbicides on birch, maple and willow
25. Glyphosate applied after leaf drop for bunchberry control
26. Napropamide for seedling weed control
27. PP333 plant growth regulator
28. Dichlobenil for bunchberry control
29. Effect of hexazinone on weed and blueberry populations
30. Fluazifop-butyl for grass control
31. Hand-wiping and cutting treatments for dogbane
32. Evaluation of airblast sprayer application of asulam for bracken fern control
33. Evaluation of spot treatment of woody weeds with 2,4-D in oil
34. Steam heat as a control of mummyberry diseas
Conditional mouse models demonstrate oncogene-dependent differences in tumor maintenance and recurrence
Diversity in the pathophysiology of breast cancer frustrates therapeutic progress. We need to understand how mechanisms activated by specific combinations of oncogenes, tumor suppressors, and hormonal signaling pathways govern response to therapy and prognosis. A recent series of investigations conducted by Chodosh and colleagues offers new insights into the similarities and differences between specific oncogenic pathways. Expression of three oncogenes relevant to pathways activated in human breast cancers (c-myc, activated neu and Wnt1) were targeted to murine mammary epithelial cells using the same transgenic tetracycline-responsive conditional gene expression system. While the individual transgenic lines demonstrate similarly high rates of tumor penetrance, rates of oncogene-independent tumor maintenance and recurrence following initial regression are significantly different, and are modifiable by mutations in specific cooperating oncogenes or loss of tumor suppressor gene expression. The experiments make three notable contributions. First, they illustrate that rates of tumor regression and recurrence following initial regression are dependent upon the pathways activated by the initiating oncogene. The experiments also demonstrate that altered expression or mutation of specific cooperating oncogenes or tumor suppressor genes results in different rates of tumor regression and recurrence. Finally, they exemplify the power of conditional mouse models for elucidating how specific molecular mechanisms give rise to the complexity of human cancer
Blueberry Advisory Committee Extension Report
The 1986 edition of the Blueberry Advisory Committee Extension Reports was prepared for the Maine Blueberry Commission and the University of Maine Blueberry Advisory Committee by researchers with the Maine Agricultural Experiment Station and Maine Cooperative Extension Service at the University of Maine, Orono. Projects in this report include:
1. Fertility Levels
2. Insect and Disease Fact Sheets
3. Development of Insect ID Information for Growers
4. Effect of Pruning Practices an Blueberry Insect Abundance
5. Control of Blueberry Maggot (Alternatives to Guthion)
6. Economic Thresholds and Control of Secondary Blueberry Pests
7. Chemical Control of Mummyberry Disease
8. Chemical Control of Botrytis Bloom Blight
9. Effects of Late Summer Fungicide Applications
10. Mowing vs. Burning - Comparisons of Disease Incidence
11. Long-term Effects of N and NPK Fertilizer on Plant Growth and Yield
12. Effect of Several Mulches on Frost Heaving, Soil Moisture, Soil Temperature and Rhizome Development
13. Interaction of Fertility and Pruning Practices on Soil
14. Effect of Block Freezing on Physical Characterization and Sugar Migration on Lowbush Blueberries
15. Demonstration of the Rota-Cone Vacuum Drying Process on Lowbush Blueberries
16. Production of a Blueberry Gelatin
17. Isolation and Characterization of Blueberry Pectin
18. The Effect of pH, Chemicals and Holding time-temperature on the color of Blueberry Puree
19. Effect of Hexazinone on Species Distribution in Lowbush Blueberry Fields
20. Evaluation of Postemergent Herbicides for Grass Control
21. Evaluation of Sulfonyl urea and lmidazoline compounds for Bunchberry Control
22. Use of Mechanical wiper with glyphosate or dicamba for control of dogbane
23. Hand-wiper Applications of Herbicides on Woody Weeds
24. Dogbane Control with 2% Glyphosate
25. Low Volume Solution of Asulam for Bracken Fern Control
26. Integrated Weed Management
27. 1986 Annual Report to the Maine Lowbush Blueberry Commissio
Bioinformatics and Functional Analysis of an Entamoeba histolytica Mannosyltransferase Necessary for Parasite Complement Resistance and Hepatical Infection
The glycosylphosphatidylinositol (GPI) moiety is one of the ways by which many cell surface proteins, such as Gal/GalNAc lectin and proteophosphoglycans (PPGs) attach to the surface of Entamoeba histolytica, the agent of human amoebiasis. It is believed that these GPI-anchored molecules are involved in parasite adhesion to cells, mucus and the extracellular matrix. We identified an E. histolytica homolog of PIG-M, which is a mannosyltransferase required for synthesis of GPI. The sequence and structural analysis led to the conclusion that EhPIG-M1 is composed of one signal peptide and 11 transmembrane domains with two large intra luminal loops, one of which contains the DXD motif, involved in the enzymatic catalysis and conserved in most glycosyltransferases. Expressing a fragment of the EhPIG-M1 encoding gene in antisense orientation generated parasite lines diminished in EhPIG-M1 levels; these lines displayed reduced GPI production, were highly sensitive to complement and were dramatically inhibited for amoebic abscess formation. The data suggest a role for GPI surface anchored molecules in the survival of E. histolytica during pathogenesis
Effective treatment of experimental U-87MG human glioblastoma in nude mice with a targeted cytotoxic bombesin analogue, AN-215
Some brain tumours, such as glioblastomas express high levels of receptors for bombesin/gastrin releasing peptide. We investigated whether bombesin/gastrin releasing peptide receptors found in glioblastoma cell lines can be utilised for targeting of a cytotoxic bombesin analogue, AN-215 consisting of a potent derivative of doxorubicin, 2-pyrrolino-doxorubicin (AN-201) linked to a bombesin-like peptide carrier. This study reports the effect of AN-215 on the growth of U-87MG human glioblastomas xenografted into nude mice. High affinity binding of AN-215 to U-87MG tumours was characterised by an IC50 value of 4.0±0.1 nM, as determined by radioreceptor assays. mRNA analyses revealed the presence of mRNA for BN receptor subtypes 1 and 2. Treatment with AN-215 significantly (P<0.05) extended tumour doubling time from 4.54±0.2 days to 8.18±1.8 days and inhibited tumour growth as demonstrated by a 69.6% reduction in final tumour volume (P<0.001) and a 64.6% decrease in tumour weight as compared to controls. Cytotoxic radical AN-201 at the same dose was ineffective. The antitumour effect of AN-215 could be blocked by pretreatment with an excess of a bombesin antagonist, indicating that the action of this cytotoxic analogue is receptor-mediated. Our results suggest that patients with inoperable brain tumours such as malignant gliomas may benefit from targeted chemotherapy based on cytotoxic bombesin analogue AN-215
Adaptive Melanin Response of the Soil Fungus Aspergillus niger to UV Radiation Stress at “Evolution Canyon”, Mount Carmel, Israel
BACKGROUND:Adaptation is an evolutionary process in which traits in a population are tailored by natural selection to better meet the challenges presented by the local environment. The major discussion relating to natural selection concerns the portraying of the cause and effect relationship between a presumably adaptive trait and selection agents generating it. Therefore, it is necessary to identify trait(s) that evolve in direct response to selection, enhancing the organism's fitness. "Evolution Canyon" (EC) in Israel mirrors a microcosmic evolutionary system across life and is ideal to study natural selection and local adaptation under sharply, microclimatically divergent environments. The south-facing, tropical, sunny and xeric "African" slope (AS) receives 200%-800% higher solar radiation than the north-facing, temperate, shady and mesic "European" slope (ES), 200 meters apart. Thus, solar ultraviolet radiation (UVR) is a major selection agent in EC influencing the organism-environment interaction. Melanin is a trait postulated to have evolved for UV-screening in microorganisms. Here we investigate the cause and effect relationship between differential UVR on the opposing slopes of EC and the conidial melanin concentration of the filamentous soil fungus Aspergillus niger. We test the working hypothesis that the AS strains exhibit higher melanin content than strains from the ES resulting in higher UV resistance. METHODOLOGY/PRINCIPAL FINDINGS:We measured conidial melanin concentration of 80 strains from the EC using a spectrophotometer. The results indicated that mean conidial melanin concentration of AS strains were threefold higher than ES strains and the former resisted UVA irradiation better than the latter. Comparisons of melanin in the conidia of A. niger strains from sunny and shady microniches on the predominantly sunny AS and predominantly shady ES indicated that shady conditions on the AS have no influence on the selection on melanin; in contrast, the sunny strains from the ES displayed higher melanin concentrations. CONCLUSIONS/SIGNIFICANCE:We conclude that melanin in A. niger is an adaptive trait against UVR generated by natural selection
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