Major Compatible Solutes and Structural Adaptation of Proteins in Extremophiles

Extremophiles are the most ancient microbes on the Earth and also a center of attraction for the scientific community for research because of their ability to adapt to extreme habitats. Compatible solutes are among those factors which enable these microorganisms to thrive in such extreme habitats. Under osmotic stress, the majority of extremophiles accumulate specific organic solutes such as amino acids, sugars, polyols, and their derivatives. In addition, proteins in extremophiles are found to be evolved by changing their amino acid composition to alter the hydrophobicity of its core and surface charge to maintain activity. This chapter encompasses a comprehensive study about the role of various compatible solutes in the endurance of microorganisms under extremophilic conditions, synthesis of compatible solutes, nature of extremophilic proteins, and their applications. Furthermore, an attempt has been made to cover various strategies adopted by the scientific community while pursuing research on compatible solutes.

Structural Adaptation and Antioxidant Response of Guarianthe bowringiana (O’Brien) Dressler & W. E. Higgins (Orchidaceae Juss.) Seedlings During Ex Vitro Acclimatization

Guarianthe bowringiana is one of the oldest samples cultivated at NBG’s orchid unit glasshouses since 1970s. An efficient protocol for asymbiotic in vitro seed germination of G. bowringiana has previously been established. Given that acclimatization is a crucial step in micropropagation, this study assesses the structural adaptation and antioxidant response of G. bowringiana seedlings during ex vitro acclimatization to ex vitro conditions. The leaf surface micromorphology of the G. bowringiana juvenile plants propagated in vitro from seeds as well as the leaves of adult plants cultivated in glasshouse were analyzed using scanning electron microscopy. The levels of lipid peroxidation (TBARS level), superoxide dismutase (SOD) activity, and the photosynthetic activity were monitored for seven days from the transfer of seedlings from the in vitro cultivation vessels as they are markers indicating the response of the leaves of in vitro propagated G. bowringiana plants to oxidative stress during the early stages of acclimatization to ex vitro conditions. During the initial 2 days of the monitored acclimatization period (0–7 days), the level of photosynthetic pigments (chlorophyll a , b , and carotenoid content) increased, followed by an insignificant increase during the successive period (by the seventh day) of acclimatization. At the same time, the level of the tested antioxidant enzyme (SOD) exhibited an increasing trend throughout the acclimatization period. The SOD activities in the leaves of G. bowringiana seedlings were significantly affected when they were transferred from in vitro to ex vitro conditions due to drought stress. Thus, it was revealed that in the early stages of acclimatizing to the altered environments, G. bowringiana seedlings exhibited a rapid increase in photosynthetic pigments, superoxide dismutase activity, and lipid peroxidation levels after being transferred to ex vitro conditions. Comparison of the leaf micromorphologies of G. bowringiana plants grown under in vitro and those grown under ex vitro conditions revealed that leaf development had undergone significant changes during acclimatization to the altered conditions. In vitro to ex vitro transfer leads to a transient decrease in photosynthetic parameters.

Climate Change Adaptation of Geo-Structures in Europe: Emerging Issues and Future Steps

Climate change is already being felt in Europe, unequivocally affecting the regions’ geo-structures. Concern over this is rising, as reflected in the increasing number of studies on the subject. However, the majority of these studies focused only on slopes and on a limited geographical scope. In this paper, we attempted to provide a broader picture of potential climate change impacts on the geo-structures in Europe by gathering the collective view of geo-engineers and geo-scientists in several countries, and by considering different geo-structure types. We also investigated how geo-structural concerns are being addressed in national adaptation plans. We found that specific provisions for geo-structural adaptation are generally lacking and mainly come in the form of strategies for specific problems. In this regard, two common strategies are hazard/risk assessment and monitoring, which are mainly implemented in relation to slope stability. We recommend that in future steps, other geo-structures are likewise given attention, particularly those assessed as also potentially significantly affected by climate change. Countries considered in this study are mainly the member countries of the European Large Geotechnical Institutes Platform (ELGIP).

A Decision-Making Method Providing Sustainability to FPGA-Based SoCs by Run-Time Structural Adaptation to Mode of Operation, Power Budget, and Die Temperature Variations

One of the growing areas of application of embedded systems in robotics, aerospace, military, etc. is autonomous mobile systems. Usually, such embedded systems have multitask multimodal workloads. These systems must sustain the required performance of their dynamic workloads in presence of varying power budget due to rechargeable power sources, varying die temperature due to varying workloads and/or external temperature, and varying hardware resources due to occurrence of hardware faults. This paper proposes a run-time decision-making method, called Decision Space Explorer, for FPGA-based Systems-on-Chip (SoCs) to support changing workload requirements while simultaneously mitigating unpredictable variations in power budget, die temperature, and hardware resource constraints. It is based on the concept of Run-Time Structural Adaptation (RTSA); whenever there is a change in a system’s set of constraints, Explorer selects a suitable hardware processing circuit for each active task at an appropriate operating frequency such that all the constraints are satisfied. Explorer has been experimentally deployed on the ARM Cortex-A9 core of Xilinx Zynq XC7Z020 SoC. Its worst-case decision-making time for different scenarios ranges from tens to hundreds of microseconds. Explorer is thus suitable for enabling RTSA in systems where specifications of multiple objectives must be maintained simultaneously, making them self-sustainable.

Informal Hierarchy Strength Changes and Their Effect on Performance

Despite qualitative evidence suggesting that changes in informal hierarchy strength likely impact performance, informal hierarchy strength changes have received little theoretical or empirical attention. We address this by extending structural adaptation theory (SAT) to develop and test a theoretical model of why informal hierarchy strength changes and how those changes impact performance. Building on SAT’s principle that teams can become more ordered following stimulation, we propose that pressure subsequently increases informal hierarchy strength. In project teams where pressure starts low and increases at the midpoint, informal hierarchy should weaken early in project life and strengthen after the midpoint. We also extend SAT’s asymmetric adaptability principle to consider not just the direction but also the rate of the changes. We hypothesize that sharply strengthening informal hierarchy harms performance, but informal hierarchy strengthening gradually improves performance. SAT also implies that gradual change is promoted by inclusive discussions. Because most influential extraverts tend to squelch inclusive discussions where most influential neurotics tend to be inclusive, teams with most influential extraverts strengthen their informal hierarchy quickly where teams with most influential neurotics strengthen their informal hierarchy gradually. We find support for our theoretical model using longitudinal data and client performance ratings on self-managed project teams. Our results contribute to SAT by showing its application to informal, unplanned changes and introducing the rate of change to its asymmetric adaptability principle. Our findings also highlight the importance of shifting informal hierarchy strength research away from the predominant static approach and toward studying informal hierarchy strength changes.

Properties of transmembrane helix TM1 of the DcuS sensor kinase of Escherichia coli, the stator for TM2 piston signaling

The sensor kinase DcuS of Escherichia coli perceives extracellular fumarate by a periplasmic PASP sensor domain. Transmembrane (TM) helix TM2, present as TM2-TM2′ homo-dimer, transmits fumarate activation in a piston-slide across the membrane. The second TM helix of DcuS, TM1, is known to lack piston movement. Structural and functional properties of TM1 were analyzed. Oxidative Cys-crosslinking (CL) revealed homo-dimerization of TM1 over the complete membrane, but only the central part showed α-helical +3/+4 spacing of the CL maxima. The GALLEX bacterial two-hybrid system indicates TM1/TM1′ interaction, and the presence of a TM1-TM1′ homo-dimer is suggested. The peripheral TM1 regions presented CL in a spacing atypical for α-helical arrangement. On the periplasmic side the deviation extended over 11 AA residues (V32-S42) between the α-helical part of TM1 and the onset of PASP. In the V32-S42 region, CL efficiency decreased in the presence of fumarate. Therefore, TM1 exists as a homo-dimer with α-helical arrangement in the central membrane region, and non-α-helical arrangement in the connector to PASP. The fumarate induced structural response in the V32-S42 region is suggested to represent a structural adaptation to the shift of TM2 in the TM1-TM1′/TM2-TM2′ four-helical bundle.

Informal Hierarchy Strength Changes and Their Effect on Performance

<p>Despite qualitative evidence suggesting that changes in informal hierarchy strength likely impact performance, informal hierarchy strength changes have received little theoretical or empirical attention. We address this by extending structural adaptation theory (SAT) to develop and test a theoretical model of why informal hierarchy strength changes and how those changes impact performance. Building on SAT’s principle that teams can become more ordered following stimulation, we propose that pressure subsequently increases informal hierarchy strength. In project teams where pressure starts low and increases at the midpoint, informal hierarchy should weaken early in project life and strengthen after the midpoint. We also extend SAT’s asymmetric adaptability principle to consider not just the direction but also the rate of the changes. We hypothesize that sharply strengthening informal hierarchy harms performance, but informal hierarchy strengthening gradually improves performance. SAT also implies that gradual change is promoted by inclusive discussions. Because most influential extraverts tend to squelch inclusive discussions where most influential neurotics tend to be inclusive, teams with most influential extraverts strengthen their informal hierarchy quickly where teams with most influential neurotics strengthen their informal hierarchy gradually. We find support for our theoretical model using longitudinal data and client performance ratings on self-managed project teams. Our results contribute to SAT by showing its application to informal, unplanned changes and introducing the rate of change to its asymmetric adaptability principle. Our findings also highlight the importance of shifting informal hierarchy strength research away from the predominant static approach and towards studying informal hierarchy strength changes.</p>

Informal Hierarchy Strength Changes and Their Effect on Performance

<p>Despite qualitative evidence suggesting that changes in informal hierarchy strength likely impact performance, informal hierarchy strength changes have received little theoretical or empirical attention. We address this by extending structural adaptation theory (SAT) to develop and test a theoretical model of why informal hierarchy strength changes and how those changes impact performance. Building on SAT’s principle that teams can become more ordered following stimulation, we propose that pressure subsequently increases informal hierarchy strength. In project teams where pressure starts low and increases at the midpoint, informal hierarchy should weaken early in project life and strengthen after the midpoint. We also extend SAT’s asymmetric adaptability principle to consider not just the direction but also the rate of the changes. We hypothesize that sharply strengthening informal hierarchy harms performance, but informal hierarchy strengthening gradually improves performance. SAT also implies that gradual change is promoted by inclusive discussions. Because most influential extraverts tend to squelch inclusive discussions where most influential neurotics tend to be inclusive, teams with most influential extraverts strengthen their informal hierarchy quickly where teams with most influential neurotics strengthen their informal hierarchy gradually. We find support for our theoretical model using longitudinal data and client performance ratings on self-managed project teams. Our results contribute to SAT by showing its application to informal, unplanned changes and introducing the rate of change to its asymmetric adaptability principle. Our findings also highlight the importance of shifting informal hierarchy strength research away from the predominant static approach and towards studying informal hierarchy strength changes.</p>