<p>Over 20 different plasma proteins have been shown to have the capacity to undergo conformational changes and self-assemble into highly stable and insoluble amyloid fibrils. </p><p>One, transthyretin (TTR), consists of 127 amino acid residues arranged in eight β-strands (named A to H) and is involved in two different clinical forms of amyloidosis. In familial amyloidotic polyneuropathy (FAP), mutated TTR is found in the amyloid deposits while in senile systemic amyloidosis (SSA) only wild type TTR is present in the amyloid deposits.</p><p>In this study, we have identified a novel form of amyloidosis that is caused by the deposition of an N-terminal fragment of apolipoprotein A-IV (apoA-IV). Interestingly, apoA-IV amyloid was found deposited in a patient that also suffered from SSA. Thus, this patient had two biochemically distinct and concurrent forms of amyloidosis that were derived from apoA-IV and TTR. </p><p>We have also discovered that two different morphological deposition patterns (identified as patterns A and B) exist in TTR-derived amyloidosis. Pattern A, observed in all SSA patients studied and in half of the FAP patients examined contained large homogenous deposits that were composed of short randomly oriented fibrils. In contrast, pattern B was observed in the remaining FAP patients and was represented by smaller-sized deposits that consisted of longer fibrils that were arranged in parallel bundles. The predominant TTR component deposited also differed between the two amyloid patterns. Amyloid pattern A contained mainly C-terminal TTR fragments while pattern B amyloid consisted of full-length TTR. Our findings suggest that two different mechanisms of fibril formation may exist in TTR-derived amyloidosis. </p><p>We have found two epitopes, corresponding to strand C and H that are surface-exposed in TTR-derived amyloid fibrils but hidden and part of the hydrophobic core in the native molecular structure. This indicates that TTR undergoes partial unfolding during fibril formation. </p>

Over 20 different plasma proteins have been shown to have the capacity to undergo conformational changes and self-assemble into highly stable and insoluble amyloid fibrils. One, transthyretin (TTR), consists of 127 amino acid residues arranged in eight β-strands (named A to H) and is involved in two different clinical forms of amyloidosis. In familial amyloidotic polyneuropathy (FAP), mutated TTR is found in the amyloid deposits while in senile systemic amyloidosis (SSA) only wild type TTR is present in the amyloid deposits. In this study, we have identified a novel form of amyloidosis that is caused by the deposition of an N-terminal fragment of apolipoprotein A-IV (apoA-IV). Interestingly, apoA-IV amyloid was found deposited in a patient that also suffered from SSA. Thus, this patient had two biochemically distinct and concurrent forms of amyloidosis that were derived from apoA-IV and TTR. We have also discovered that two different morphological deposition patterns (identified as patterns A and B) exist in TTR-derived amyloidosis. Pattern A, observed in all SSA patients studied and in half of the FAP patients examined contained large homogenous deposits that were composed of short randomly oriented fibrils. In contrast, pattern B was observed in the remaining FAP patients and was represented by smaller-sized deposits that consisted of longer fibrils that were arranged in parallel bundles. The predominant TTR component deposited also differed between the two amyloid patterns. Amyloid pattern A contained mainly C-terminal TTR fragments while pattern B amyloid consisted of full-length TTR. Our findings suggest that two different mechanisms of fibril formation may exist in TTR-derived amyloidosis. We have found two epitopes, corresponding to strand C and H that are surface-exposed in TTR-derived amyloid fibrils but hidden and part of the hydrophobic core in the native molecular structure. This indicates that TTR undergoes partial unfolding during fibril formation.

Oil and gas exploration conducted in the 1970s left behind a legacy of abandoned well sites in the Mackenzie Delta region of northern Canada, including several in the Kendall Island Migratory Bird Sanctuary and surrounding areas. Evidence of 30 year-old well sites is present in the form of drilling mud sumps, which are mounds of disturbed tundra that contain frozen drilling-wastes. One to two years after the wells were decommissioned some of the sites were seeded with non-native grass species and fertilized to test whether these treatments could accelerate vegetation recovery and prevent erosion. The main objective of this research was to examine the long-term impact of post-disturbance seeding treatments on the vegetation recovery of drilling mud sumps.<p> Surveys of vegetation composition and environmental conditions at 12 sump sites (6 seeded and 6 unseeded) showed that, after over 30 years of recovery, seeded sumps in the Mackenzie Delta did not significantly differ from those left for natural recovery. However, seeded and previously introduced grasses <i>Festuca rubra</i> and <i>Poa pratensis</i> were found on both seeded and unseeded sumps. The undisturbed surrounding tundra seems to be resistant to invasion by these introduced grasses. However, these species could become invasive in the future, particularly in the context of warming in the North and increasing anthropogenic disturbance. The results of this study contribute valuable information on the long-term effects of revegetation treatments that is critical for making informed management decisions about the rehabilitation of industrial disturbances in the Arctic.

The air seeding cart is an important piece of farming equipment used in the seeding process. Three factors which are necessary to monitor during the seeding process are the seeding rate (material mass flow rate), air flow rate, and blockages. In current practice, there are systems that monitor and report air flow and blockages but not the actual seeding rate. Presently, the seeding rate is based on the metering calibration before the seeding process starts, which requires a lot of time and energy from the operator. If that goes wrong, it not only takes longer, but also costs more money and increases the already significant stress and fatigue which farmers and operators have during the seeding period. Therefore, the development of reliable, and easily calibrated, on-line sensors for flow monitoring would be beneficial. Further, such sensors would facilitate closed-loop control of the flow rate itself. In order to develop a laboratory prototype for mass flow measurement, a model for mass flow estimation was established. This was accomplished by using pressure transducers to determine the pressure drop across an elevation in the primary air cart run (between the air seeding cart and the air hoe drill). An air seeding test station was designed and developed for the study. Three different types of seeds and a granular fertilizer were chosen and tested. These tested materials were canola, wheat, chickpea and urea fertilizer (46-0-0). The general form of the model was developed using data from the canola tests. The input parameters for this mass flow estimation model were pressure drop and air flow information. The average percent error of the material mass flow rate’s full range was under 10%, except for the highest rate which tested up to 20%. Overall, more than 75% of the estimations had percent errors being less than 5%. The form of the model was also applicable to other individual tested materials with the percent error of their full ranges up to 20%. However, their average of their median error was around 5% of their full ranges. The general model was also applied to the combined data from all tested materials. The results were not as accurate as when the model was applied to the individual tested material. The median of the percent error (of material mass flow rate full range) varied from as low as 1% to as high as 30%, depending on the tested materials. Nevertheless, it demonstrated that there were consistencies between the behaviour of the four tested materials.

Oil and gas exploration conducted in the 1970s left behind a legacy of abandoned well sites in the Mackenzie Delta region of northern Canada, including several in the Kendall Island Migratory Bird Sanctuary and surrounding areas. Evidence of 30 year-old well sites is present in the form of drilling mud sumps, which are mounds of disturbed tundra that contain frozen drilling-wastes. One to two years after the wells were decommissioned some of the sites were seeded with non-native grass species and fertilized to test whether these treatments could accelerate vegetation recovery and prevent erosion. The main objective of this research was to examine the long-term impact of post-disturbance seeding treatments on the vegetation recovery of drilling mud sumps.<p> Surveys of vegetation composition and environmental conditions at 12 sump sites (6 seeded and 6 unseeded) showed that, after over 30 years of recovery, seeded sumps in the Mackenzie Delta did not significantly differ from those left for natural recovery. However, seeded and previously introduced grasses <i>Festuca rubra</i> and <i>Poa pratensis</i> were found on both seeded and unseeded sumps. The undisturbed surrounding tundra seems to be resistant to invasion by these introduced grasses. However, these species could become invasive in the future, particularly in the context of warming in the North and increasing anthropogenic disturbance. The results of this study contribute valuable information on the long-term effects of revegetation treatments that is critical for making informed management decisions about the rehabilitation of industrial disturbances in the Arctic.

Precision management of cotton production can increase profitability by decreasing inputs. The overall objective of this project is to improve cotton production by minimizing seeding rates while still maximizing yields and lint quality in water-limited soils. The research for this study was conducted at the Texas AgriLife Research IMPACT Center located in the Brazos River floodplain. In 2008 and 2009, 27 measurement locations were selected in production-sized center-pivot irrigated fields and planted in cotton variety Deltapine 164 roundup ready flex / bollgard II. Sites were selected based on soil apparent electrical conductivity (ECa) values, in a low, medium, and high ECa zones. Three seeding rates (74,100; 98,800; and 123,500 seeds ha-1) were established in each of the three ECa zones with three replications. In 2009, an additional seeding rate was added at 49,400 seeds ha-1. At each measurement location, soil texture, soil moisture (weekly), lint quantity and quality (High Volume Instrument) were measured. An additional replication for each ECa zone and seeding rate was selected for lint quantity and quality (HVI) measurements. Results indicated that cotton lint yield increased as ECa values, clay content, and water holding capacity of the soil increased. The seeding rates did not consistently affect cotton lint yield or quality. Seeding rates of 74,100 and 49,400 seeds ha-1 in a low and medium ECa zone for IMPACT-08 and -09 yielded more lint (300 kg ha-1), respectively. HVI lint quality parameters, such as, micronaire, fiber length, strength, uniformity, and elongation were significantly better in ECa zone 3. While the seeding rates did not affect the amount of soil water used throughout the season, lint yield variations between ECa zones can be explained by the rate at which soil water was used. Lower rates at which soil water was used within ECa zone 3 resulted in higher lint yields when compared to ECa zones 1 and 2, which used soil water faster and at greater depths. The findings suggest that irrigation applied to the low ECa zone was not sufficient to meet the plants demand, while in a high ECa zone, irrigation could have been reduced, resulting in cost savings through reduced inputs.

Effect of soil moisture potential (?), temperature (T), genotype, seeding depth (SD) and rate (SR) on seedling emergence (SE), emergence velocity (EV), root yield and grades of cut and peel carrots were studied. SE was reduced at –120 kPa and totally inhibited at -156 kPa. EV was the lowest at – 5 kPa and – 90 kPa. SE was delayed by 33 d at 5°C, reduced at 30°C and totally inhibited at 35 and 40 °C. Heat units 99.75 and 159.60°Cd were the lowest to initiate and complete SE respectively while the optimum was 300 – 350 °Cd. There was no interaction effect between ? and T on SE. Honey snax at 85 seeds/ 30 cm showed the best SE whereas, Triton recorded the highest total yield at 2.54 cm SD and Fancy yield at 85 seeds/ 30 cm implying certain crop ecological and management factors can influence SE, root yield and quality.

Magistrantūros studijų baigiamajame darbe pateikiami ilgalaikio supaprastinto žemės dirbimo ir tiesioginės sėjos įtaka žieminių kviečių agrocenozei tyrimo rezultatai. Darbo objektas – pagrindinio žemės dirbimo būdai žieminiams kviečiams. Darbo metodai: buvo tirti tokie žemės dirbimo būdai: 1) įprastinis arimas 23–25 cm gyliu; 2) seklusis arimas 12–14 cm gyliu; 3) gilusis purenimas 23–25 cm gyliu; 4) seklusis purenimas 12–15 cm gyliu; 5) tiesioginė sėja į neįdirbtą dirvą. Atlikti šie stebėjimai: Dirvos agrocheminių savybių nustatymas, piktžolėtumo nustatymas, žieminių kviečių daigų tankumas, sliekų kiekis dirvoje, produktyvių stiebų tankumas, derliaus apskaita, bei 1000 grūdų masė. Darbo rezultatai. Nustatyta, kad tiesioginė sėja, bei gilusis purenimas esmingai padidino trumpaamžių piktžolių daigų tankumą žieminių kviečių pasėlyje, o taikant seklaus purenimo būdą esmingai padidėjo daugiamečių piktžolių daigų tankumas lyginant su įprastai suarta dirva. Žieminių kviečių vegetacijos pabaigoje esmingai padidėjo daugiamečių piktžolių masė sekliai artuose, giliai purentuose ir sekliai purentuose laukeliuose, lyginant su įprastiniu arimu. Įprastinį arimą pakeitus giliu purenimu, sekliu purenimu ir tiesiogine sėja į neįdirbtą dirvą, atsinaujinus žieminių kviečių vegetacijai nustatyta esmingai didesnis dirvinio garstuko daigų tankumas. Taikant ilgalaikę tiesioginę sėją žieminių kviečių vegetacijos pabaigoje nustatyta esmingai didesnis paprastosios rietmenės daigų skaičius ir masė... [toliau žr. visą tekstą] / Master's thesis presents the results of the investigation of effects of long-term reduced tillage and direct seeding on winter wheat agrocenoses. Object of work – are the main methods of tillage for winter wheat. Research methods: the following tillage methods were investigated: 1) conventional ploughing at the depth of 23–25 cm, 2) shallow ploughing at the depth of 12–14 cm, 3) deep loosening at the depth of 23–25 cm, 4) shallow loosening at the depth of 12–15 cm; 5) direct seeding into uncultivated soil. The following sampling were performed: soil agrochemical properties, weed abundance, winter wheat seedling density, quantity of earthworms in soil, productive stems density, yield and 1000 grain weight. Results. It was found that direct seeding and deep loosening substantially increased the annual weed seedling density of winter wheat crop, while the shallow method of loosening significantly increased weed seedling density compared to normal ploughing soil. The mass of perennial weeds has increased substantially at the end of the winter wheat growing season in shallow ploughing, deeply loosened and shallow ploughing plots compared to conventional ploughing. When normal ploughing was replaced with deep loosening, shallow loosening and direct seeding in the uncultivated soil after the recurrence of winter wheat vegetation, the density of Sinapis arvensis L. shoots increased significantly. When applying long-term direct seeding at the end of winter wheat growing season, the... [to full text]

This study provides ex ante estimates of multi factor productivity (MFP) growth in the Saskatchewan agricultural sector on a crop by crop basis, using a time series of partial budgets from representative crop planning Guide. The study considers six major crops in Saskatchewan: spring wheat, durum wheat, feed barley, feed peas, large green lentils and canola. MFP growth is compared across crops, soil zones and cropping systems. Over the 1993-2013 period all six crops MFP grew at rates of over 2.56% per year. Feed peas and canola showed the fastest growth rates of 4.68% and 4.01%, respectively. The MFP growth of crops seeded on summer-fallow was slower than crops seeded into stubble using conventional tillage and zero tillage. The best soil zone for durum wheat and lentils, in term of productivity growth, was the Brown Soil zone; while for peas and canola, it is the Dark Brown Soil zone. Spring wheat and barley grown in different soil zones had very similar productivity gains.

Aciphylla species (wild spaniard/speargrass) are an iconic component of the Australasian high country flora, but their reproductive system is enigmatic. They are insect-pollinated dioecious mast seeders (synchronous highly variable seed production), which seems maladaptive. The resource supply to pollinators is highly variable, yet dioecious plants are dependent on pollinators, and dioecious masting requires male and female plants to flower synchronously. Floral display in Aciphylla is relatively large, with tall inflorescences bearing thousands of flowers, suggesting that plants would not have the resources to produce such large stalks every year. But why do they have such huge inflorescences in the first place? I tested whether pollinator attraction is providing an economy of scale which favours intermittent production of very large inflorescences, by manipulating floral display size during a high-flowering year and measuring insect visitation rates and seed set (female reproductive success). Using space-for-time substitution and selective removal of male inflorescences, I also tested whether female seed set was affected by distance to flowering male plants (i.e. changes in local pollen availability) to see if flowering asynchrony would reduce pollination success. Bags were used to exclude pollination by insects and test for wind pollination, and hand pollination was done to test for pollen limitation. Insect surveys suggest that Aciphylla has a generalist pollination system (to avoid satiating a specialist pollinator during 'mast' years'). Male inflorescences received significantly more visits than females, and some seeds were set inside bags (although only 20-30%), suggesting wind pollination may occur at low levels. Seed set rate was higher for taller inflorescences with greater flowering length in A. aurea but tall inflorescences with excess flowers led to a decrease in seed set rates in A. scott-thomsonii. Hand pollination significantly increased seed set rates although these effects were not as large as expected (e.g. 10% increases from natural to hand-pollinated inflorescences were typical). There was no evidence for resource limitation in any species. Female plants in dense flowering populations had higher seed set rates, and individual floral display size in females was particularly important when females were 'isolated' from males. Insect visitation rates were generally higher on inflorescences with a larger floral display, suggesting that display size is important for pollinator attraction. Overall, these results suggest that the pollinator-attraction benefits of such a large floral display (at both the plant and population level) are possibly providing an economy of scale, although the relative effects are small.