Problems with classification of polineuropaties severity in case of hereditary ones – review of literature

Evaluation of neuropathy severity is still a challenge for a modern medicine. Many scales were made to resolve this problem but each of them has limitations. It is known that in case of many patients there is no relation between clinical status and nerve conduction studies (NCS) results. Severe disabled patients with neuropathies can have nerve conduction study result mild impaired and conversely relation is also often observed. Many screening instruments with numerous composite scores are used to evaluate neuropathy. Most of them involved sensory perception, motor functions and reflexes like Neuropathy Disability Score (NDS), Neuropathy Impairment Score (NIS), Thoronto Clinical Neuropathy Scoring System. Electrophysiological parameters are also useful in classification of disease types especially in Charcot-Marie-Tooth one. There were many attempts of discovering new scores especially in diabetic neuropathies, involving mainly clinical features. There is lack of easy, reliable and precise scores that could improve neuropathy classification and monitoring disease progression especially in case of hereditary polyneuropathy

Biological evolution and the physics of growing microbial colonies

In this thesis I investigate the role of spatial structure, cell-cell interactions and horizontal gene transfer on the genetic composition of growing microbial colonies. In the first part I study how the roughness of the growing layer of the colony depends on the shape of colony-forming cells. To study its impact I develop an off-lattice Eden-like model in which cells are represented as spherocylinders with a variable aspect ratio. I show that the roughness of the expansion front is not significantly affected by the shape of cells and that the dynamic scaling of growing front belongs to the KPZ universality class. Roughness is an important and easy to measure feature which affects the probability of fixation of genetic lineages in the colony. Another feature contributing to the genetic composition of a microbial community is horizontal gene transfer, which is investigated in the second part of this thesis. I develop an agent-based computational model of bacterial cells which grow, divide, and interact mechanically. I focus on plasmid conjugation, in which donors transfer a plasmid (a small, circular DNA molecule) to plasmid-free recipients. I show that bacteria in the expanding colony segregate into sectors of donors and acceptors. Donor sectors grow at the expense of acceptor sectors and that effect can be effectively described by coalescing random walkers that perform biased random walk on the colony expansion front. I use numerical and analytical methods to show that the plasmid eventually spreads to the whole colony given enough time, and I also show that this time is unrealistically long for experimentally determined conjugation rates and therefore real colonies are expected to have both acceptor and donor sectors. Furthermore, my simulations show that segregative plasmid loss at the moment of cell division can counteract the effect of conjugation and can lead to fixation of plasmid free cells. I also show that changes in nutrient concentration and the resultant change in roughness of the expansion front affect the rate of plasmid spread into population. Quantitative and qualitative results obtained in this section may serve as a tool to extract plasmid invasion rates from experimental data. In the last part of this thesis I investigate how the physical factors, such as finite strength of conjugative junctions, affect the conjugation process. I develop a computational model of plasmid transfer in which conjugative junctions are explicitly modelled as short, spring-like tubes that connect conjugating cells. My results show that factors such as junction creation rate and its strength can significantly affect the conjugation performance. I study different situations corresponding to different experimental scenarios (well-mixed colony on a filter paper, colliding colonies) and show that shear forces acting between cells can significantly lower the rate of plasmid transfer. My results can explain why conjugation occurs very rarely in some of these scenarios investigates in laboratory assays

Reducing flower competition for assimilates by half results in higher yield of Fagopyrum esculentum

Despite abundant flowering throughout the season, common buckwheat develops a very low number of kernels probably due to competition for assimilates. We hypothesized that plants with a shorter flowering period may give a higher seed yield. To verify the hypothesis, we studied nutrient stress in vitro and in planta and analyzed different embryological and yield parameters, including hormone profile in the flowers. In vitro cultivated flowers on media with strongly reduced nutrient content demonstrated a drastic increase in degenerated embryo sacs. In in planta experiments, where 50% or 75% of flowers or all lateral ramifications were removed, the reduction of the flower competition by half turned out to be the most promising treatment for improving yield. This treatment increased the frequency of properly developed embryo sacs, the average number of mature seeds per plant, and their mass. Strong seed compensation under 50% inflorescence removal could result from increased production of salicylic and jasmonic acid that both favor more effective pollinator attraction. Plants in single-shoot cultivation finished their vegetation earlier, and they demonstrated greater single seed mass per plant than in control. This result suggests that plants of common buckwheat with shorter blooming period could deliver higher seed yield

Physiological and Biochemical Response to Fusarium culmorum Infection in Three Durum Wheat Genotypes at Seedling and Full Anthesis Stage

Fusarium culmorum is a worldwide, soil-borne plant pathogen. It causes diseases of cereals, reduces their yield, and fills the grain with toxins. The main direction of modern breeding is to select wheat genotypes the most resistant to Fusarium diseases. This study uses seedlings and plants at the anthesis stage to analyze total soluble carbohydrates, total and cell-wall bound phenolics, chlorophyll content, antioxidant activity, hydrogen peroxide content, mycotoxin accumulation, visual symptoms of the disease, and Fusarium head blight index (FHBi). These results determine the resistance of three durum wheat accessions. We identify physiological or biochemical markers of durum wheat resistance to F. culmorum. Our results confirm correlations between FHBi and mycotoxin accumulation in the grain, which results in grain yield decrease. The degree of spike infection (FHBi) may indicate accumulation mainly of deoxynivalenol and nivalenol in the grain. High catalase activity in the infected leaves could be considered a biochemical marker of durum sensitivity to this fungus. These findings allowed us to formulate a strategy for rapid evaluation of the disease severity and the selection of plants with higher level, or resistance to F. culmorum infection

Physiological and Biochemical Parameters of Salinity Resistance of Three Durum Wheat Genotypes

The area of farming lands affected by increasing soil salinity is growing significantly worldwide. For this reason, breeding works are conducted to improve the salinity tolerance of important crop species. The goal of the present study was to indicate physiological or biochemical parameters characterizing three durum wheat accessions with various tolerance to salinity. The study was carried out on germinating seeds and mature plants of a Polish SMH87 line, an Australian cultivar ‘Tamaroi’ (salt-sensitive), and the BC5Nax2 line (salt-tolerant) exposed to 0–150 mM NaCl. Germination parameters, electrolyte leakage (EL), and salt susceptibility index were determined in the germinating caryopses, whereas photosynthetic parameters, carbohydrate and phenolic content, antioxidant activity as well as yield were measured in fully developed plants. The parameters that most differentiated the examined accessions in the germination phase were the percentage of germinating seeds (PGS) and germination vigor (Vi). In the fully developed plants, parameters included whether the plants had the maximum efficiency of the water-splitting reaction on the donor side of photosystem II (PSII)–Fv/F0, energy dissipation from PSII–DIo/CSm, and the content of photosynthetic pigments and hydrogen peroxide, which differentiated studied genotypes in terms of salinity tolerance degree. Salinity has a negative impact on grain yield by reducing the number of seeds per spike and the mass of one thousand seeds (MTS), which can be used as the most suitable parameter for determining tolerance to salinity stress. The most salt-tolerant BC5Nax2 line was characterized by the highest PGS, and Vi for NaCl concentration of 100–150 mM, content of chlorophyll a, b, carotenoids, and also MTS at all applied salt concentrations as compared with the other accessions. The most salt-sensitive cv. ‘Tamaroi’ demonstrated higher H2O2 concentration which proves considerable oxidative damage caused by salinity stress. Mentioned parameters can be helpful for breeders in the selection of genotypes the most resistant to this stress

Antioxidant activity as a response to cadmium pollution in three durum wheat genotypes differing in salt-tolerance

Durum wheat is commonly used in various food industry industries and cultivated worldwide. A serious problem with the species cultivation is its capability to accumulate cadmium (Cd) in the grains. The aim of this study is to investigate whether antioxidant activity may be used as a marker of Cd tolerance in durum wheat. The experiment involved three durum wheat genotypes/lines differing in salt tolerance. The plant response to Cd was appraised based on the activity of ascorbate–glutathione (AsA–GSH) cycle enzymes, ascorbate-to-dehydroascorbate ratio, reduced-to-oxidized glutathione ratio (GSH:GSSG), as well as Cd content in the seeds. The highest activity of dehydroascorbate reductase, monodehydroascorbate reductase, and glutathione reductase was noted in control plants of salt-sensitive cultivar “Tamaroi.” In the presence of Cd, activity of these enzymes was considerably reduced. “Tamaroi” plants demonstrated also the highest Cd content in the grain. In conclusion, we identified the cultivar “Tamaroi” as most susceptible to cadmium, and the level of durum wheat sensitivity to the element can be evaluated based on a significant decrease in the activity of AsA–GSH cycle enzymes and GSH:GSSG ratio

Seed Hydropriming and Smoke Water Significantly Improve Low-Temperature Germination of Lupinus angustifolius L.

Seed imbibition under cold temperature is dangerous when dry seeds have relatively low water content. The aim of this study was to investigate germination of 20 lines/cultivars of narrow-leaf lupine at 7 °C (cold) and 13 °C (control) under the influence of smoke water and following seed hydropriming for 3 h at 20 °C. The efficacy of individual treatments was examined with regard to seed protection during low-temperature germination. Based on seed germination, vigour at cold was evaluated four days after sowing by means of hypocotyl length, the studied lines/cultivars were divided into three groups with low, high and very high germination rates. Germination vigour correlated with cell membrane permeability, dehydrogenase activity and abscisic acid (ABA) content and was analysed in the seeds one day after sowing. Gibberellin content did not correlate with germination vigour. The seeds of weakly germinating lines/cultivars had the highest cell permeability and ABA content as well as the lowest amylolytic activity at both studied temperatures. Additionally, the vigour of weakly germinating seeds at 7 °C correlated with dehydrogenase activity. Three-hour hydropriming was the most effective for seed germination under cold due to reduced cell membrane permeability and ABA level. Stimulating effects of smoke water on germination under cold could be explained by enhanced dehydrogenase activity

Changes in the Flower and Leaf Proteome of Common Buckwheat (Fagopyrum esculentum Moench) under High Temperature

Common buckwheat (Fagopyrum esculentum Moench), a pseudocereal crop, produces a large number of flowers, but this does not guarantee high seed yields. This species demonstrates strong abortion of flowers and embryos. High temperatures during the generative growth phase result in an increase in the degeneration of embryo sacs. The aim of this study was to investigate proteomic changes in flowers and leaves of two common buckwheat accessions with different degrees of heat tolerance, Panda and PA15. Two-dimensional gel electrophoresis and mass spectrometry techniques were used to analyze the proteome profiles. Analyses were conducted for flower buds, open flowers capable of fertilization, and wilted flowers, as well as donor leaves, i.e., those growing closest to the inflorescences. High temperature up-regulated the expression of 182 proteins. The proteomic response to heat stress differed between the accessions and among their organs. In the Panda accession, we observed a change in abundance of 17, 13, 28, and 11 proteins, in buds, open and wilted flowers, and leaves, respectively. However, in the PA15 accession there were 34, 21, 63, and 21 such proteins, respectively. Fifteen heat-affected proteins were common to both accessions. The indole-3-glycerol phosphate synthase chloroplastic-like isoform X2 accumulated in the open flowers of the heat-sensitive cultivar Panda in response to high temperature, and may be a candidate protein as a marker of heat sensitivity in buckwheat plants