Ploidy levels and reproductive behaviour in invasive Hieracium pilosella in Patagonia

Within a population of invasive Hieracium pilosella in Chilean Patagonia we found two ploidy levels, pentaploid and hexaploid. Each ploidy level was represented by one clone. Their reproductive system was apomictic (and thus replicating the maternal genome), with a low degree of residual sexuality. It is necessary to prevent the evolution of new biotypes via hybridisation with different clones of H. pilosella or other Hieracium species introduced into Patagonia

Stepwise metabolic adaption from pure metabolization to balanced anaerobic growth on xylose explored for recombinant Saccharomyces cerevisiae

BACKGROUND: To effectively convert lignocellulosic feedstocks to bio-ethanol anaerobic growth on xylose constitutes an essential trait that Saccharomyces cerevisiae strains normally do not adopt through the selective integration of a xylose assimilation route as the rate of ATP-formation is below energy requirements for cell maintenance (m(ATP)). To enable cell growth extensive evolutionary and/or elaborate rational engineering is required. However the number of available strains meeting demands for process integration are limited. In this work evolutionary engineering in just two stages coupled to strain selection under strict anaerobic conditions was carried out with BP10001 as progenitor. BP10001 is an efficient (Y(ethanol) = 0.35 g/g) but slow (q(ethanol) = 0.05 ± 0.01 g/g(BM)/h) xylose-metabolizing recombinant strain of Saccharomyces cerevisiae that expresses an optimized yeast-type xylose assimilation pathway. RESULTS: BP10001 was adapted in 5 generations to anaerobic growth on xylose by prolonged incubation for 91 days in sealed flasks. Resultant strain IBB10A02 displayed a specific growth rate μ of 0.025 ± 0.002 h(-1) but produced large amounts of glycerol and xylitol. In addition growth was strongly impaired at pH below 6.0 and in the presence of weak acids. Using sequential batch selection and IBB10A02 as basis, IBB10B05 was evolved (56 generations). IBB10B05 was capable of fast (μ = 0.056 ± 0.003 h(-1); q(ethanol) = 0.28 ± 0.04 g/g(BM)/h), efficient (Y(ethanol) = 0.35 ± 0.02 g/g), robust and balanced fermentation of xylose. Importantly, IBB10A02 and IBB10B05 displayed a stable phenotype. Unlike BP10001 both strains displayed an unprecedented biphasic formation of glycerol and xylitol along the fermentation time. Transition from a glycerol- to a xylitol-dominated growth phase, probably controlled by CO(2)/HCO(3)(-), was accompanied by a 2.3-fold increase of m(ATP) while Y(ATP) (= 87 ± 7 mmol(ATP)/g(BM)) remained unaffected. As long as glycerol constituted the main by-product energetics of anaerobic growth on xylose and glucose were almost identical. CONCLUSIONS: In just 61 generation IBB10B05, displaying ~530% improved strain fitness, was evolved from BP10001. Its excellent xylose fermentation properties under industrial relevant conditions were proven and rendered it competitive. Based on detailed analysis of growth energetics we showed that m(ATP) was predominantly determined by the type of polyol formed rather than, as previously assumed, substrate-specific

Process intensification through microbial strain evolution: mixed glucose-xylose fermentation in wheat straw hydrolyzates by three generations of recombinant Saccharomyces cerevisiae

BACKGROUND: Lignocellulose hydrolyzates present difficult substrates for ethanol production by the most commonly applied microorganism in the fermentation industries, Saccharomyces cerevisiae. High resistance towards inhibitors released during pretreatment and hydrolysis of the feedstock as well as efficient utilization of hexose and pentose sugars constitute major challenges in the development of S. cerevisiae strains for biomass-to-ethanol processes. Metabolic engineering and laboratory evolution are applied, alone and in combination, to adduce desired strain properties. However, physiological requirements for robust performance of S. cerevisiae in the conversion of lignocellulose hydrolyzates are not well understood. The herein presented S. cerevisiae strains IBB10A02 and IBB10B05 are descendants of strain BP10001, which was previously derived from the widely used strain CEN.PK 113-5D through introduction of a largely redox-neutral oxidoreductive xylose assimilation pathway. The IBB strains were obtained by a two-step laboratory evolution that selected for fast xylose fermentation in combination with anaerobic growth before (IBB10A02) and after adaption in repeated xylose fermentations (IBB10B05). Enzymatic hydrolyzates were prepared from up to 15% dry mass pretreated (steam explosion) wheat straw and contained glucose and xylose in a mass ratio of approximately 2. RESULTS: With all strains, yield coefficients based on total sugar consumed were high for ethanol (0.39 to 0.40 g/g) and notably low for fermentation by-products (glycerol: ≤0.10 g/g; xylitol: ≤0.08 g/g; acetate: 0.04 g/g). In contrast to the specific glucose utilization rate that was similar for all strains (q(Glucose) ≈ 2.9 g/g(cell dry weight (CDW))/h), the xylose consumption rate was enhanced by a factor of 11.5 (IBB10A02; q(Xylose) = 0.23 g/g(CDW)/h) and 17.5 (IBB10B05; q(Xylose) = 0.35 g/g(CDW)/h) as compared to the q(Xylose) of the non-evolved strain BP10001. In xylose-supplemented (50 g/L) hydrolyzates prepared from 5% dry mass, strain IBB10B05 displayed a q(Xylose) of 0.71 g/g(CDW)/h and depleted xylose in 2 days with an ethanol yield of 0.30 g/g. Under the conditions used, IBB10B05 was also capable of slow anaerobic growth. CONCLUSIONS: Laboratory evolution of strain BP10001 resulted in effectively enhanced q(Xylose) at almost complete retention of the fermentation capabilities previously acquired by metabolic engineering. Strain IBB10B05 is a sturdy candidate for intensification of lignocellulose-to-bioethanol processes

Stage Center Theatre Newsletter- Feb. 2012

https://neiudc.neiu.edu/stagecenter/1036/thumbnail.jp

Stage Center Theatre Newsletter- Apr. 2012

https://neiudc.neiu.edu/stagecenter/1037/thumbnail.jp

Optimization of proprioceptive stimulation for echo-planar and inverse magnetic resonance imaging

In echo-planar imaging (EPI), the optimal passive movement parameters (rate and duration) for studying proprioceptive brain responses are unknown. The aim of this thesis was to test the effect of stimulus rate on brain responses evoked by proprioceptive stimulation in EPI. In addition, we attempted to develop a measurement protocol for experiments focused on proprioception in ultrafast inverse magnetic resonance imaging (InI) and investigate the amplitude of blood oxygen level-dependent (BOLD) signal at varying stimulus duration. This experimental setup was supposed to be applied in future connectivity studies of the proprioceptive brain network. We found that the optimum rate for right index finger proprioceptive stimulation in EPI varies from 3 to 6 Hz. While we managed to sample the BOLD responses every 100 ms (a 20-fold increase in temporal resolution compared to EPI), the experimental design in InI is challenging due to methodological constraints. Thus, the appropriate stimulation parameters for InI still remain a topic for further research

Implementation of an application demonstrating microservices advantages and disadvantages

Cílem bakalářské práce je vytvořit ukázkovou aplikaci pro demonstraci výhod a nevýhod architektury microservices. První část bakalářské práce je zaměřena na architekturu microservices, co to microservice je a jakým způsobem se aplikace na architektuře microservices implementuje. V druhé části jsou popsány vlastnosti dvou aplikací z korporátního prostředí, které jsou v současné době implementovány monoliticky. Třetí část bakalářské práce je zaměřena na popis vývoje backendu a frontendu ukázkové aplikace na architektuře microservices. Třetí část také obsahuje uživatelské scénáře, na kterých je demonstrována výhoda microservices. Závěrečná část se zabývá výhodami a nevýhodami architektury microservices včetně vyhodnocení náročnosti samotného vývoje.The aim of the bachelor thesis is to create a sample application to demonstrate the advantages and disadvantages of the microservices architecture. The first part of the bachelor thesis is focused on microservices architecture, what microservices is and how the application for the microservices architecture is implemented. The second part describes the properties of two corporate applications that are currently being implemented monolithically. The third part of the bachelor thesis is focused on description of backend and frontend development of sample application for microservices architecture. The third part includes user scenarios where the advantage of microservices is demonstrated. The last part deals with the advantages and disadvantages of the microservices architecture, including the evaluation of the complexity of the development itself