Uncharacterized bacterial structures revealed by electron cryotomography

Electron cryotomography (ECT) can reveal the native structure and arrangement of macromolecular complexes inside intact cells. This technique has greatly advanced our understanding of the ultrastructure of bacterial cells. We now view bacteria as structurally complex assemblies of macromolecular machines rather than as undifferentiated bags of enzymes. To date, our group has applied ECT to nearly 90 different bacterial species, collecting more than 15,000 cryotomograms. In addition to known structures, we have observed, to our knowledge, several uncharacterized features in these tomograms. Some are completely novel structures; others expand the features or species range of known structure types. Here, we present a survey of these uncharacterized bacterial structures in the hopes of accelerating their identification and study, and furthering our understanding of the structural complexity of bacterial cells

Control strategies for heat pumps in a residential area under consideration of system operator benefits and grid stability

The energy sector faces challenges due to the increasing use of weather-depending renewables in power generation. The resulting fluctuations must be balanced through storage technologies and Demand Side Management (DSM) methods. Heat pumps are generally recognized as shiftable loads for DSM. More and more heat pump manufacturers in Germany are using the Smart-Grid- (SG-) Ready interface, which enables grid operators on the one hand and system operators on the other hand to control heat pumps for the purpose of DSM aiming at either grid power balancing (grid operator friendly) or to increase the self-consumption rate of the residential energy system (system operator friendly). The presented work aims at a compromise between those two goals. To this end, different control strategies for SG-Ready enabled solar and heat pump systems are implemented in a simulation framework and evaluated for a residential area using different key performance indicators. The results show that a control strategy based on a dynamic price signal (PRBC2) with rule-based control and well-chosen switching points, taking into account considered building energy systems and environmental conditions used here, represents the best compromise between system operator friendly behavior and grid operator serviceability. The choice of switching points for the heat pump in the course of the price signal is crucial here, and must take into account the consumption and generation profiles of the local residential areas. The fulfillment value of the key indicators considered here for the representative residential area is 63.9%, whereas the value with the reference operating strategy, in which the heat pump is operated exclusively in SG-Ready Mode 2, is only 50.6%

Development of Enzyme Linked Immunosorbent Assay for humoral immuneresponse and infection monitoring of anthrax

ΔΕΝ ΔΙΑΤΙΘΕΤΑΙ ΠΕΡΙΛΗΨΗImmune assays were taken into consideration to diagnose and quantify metabolites such as antigen and antibody. Enzyme-Linked Immunosorbent Assays (ELISAs), which are used to detect antigens and antibodies, generated several periods of infectious and vaccination conditions. There is an extensive range of commercial infectious disease ELISA kits useful for the detection of human and animal IgG, IgA, IgM antibodies and microorganism antigens. Anthrax is one of the serious infectious diseases caused by rod-shaped, gram-positive bacteria known as Bacillus anthracis. Subunit or attenuated vaccines applied against anthrax disease increase the antibody against the Protective Antigen (PA) which has a critical role as a toxin of B. anthracis. Herein, the ELISA was developed using PA domain 4 and anthrax Lethal Factor to detect IgG antibody in serum. Besides, the level of anti-LF antibodies were determined as a complementary test to measure variance in antibody titers associated with vaccination or infection that leads to detection of anthrax in livestock. The results show that we developed high-quality ELISA kit that can be used to test immunogenicity of vaccines and infections in mice. We tried to develop the Anti- PA4 ELISA kit and conduct the validation studies to evaluate the fluctuation level of the antibody in the anthrax vaccine and distinction between disease and vaccination in mice

The biomechanics of the locust ovipositor valves : a unique digging apparatus

The female locust has a unique mechanism for digging in order to deposit its eggs deep in the ground. It utilizes two pairs of sclerotized valves to displace the granular matter, while extending its abdomen as it propagates underground. This ensures optimal conditions for the eggs to incubate, and provides them with protection from predators. Here, two major axes of operation of the digging valves are identified, one in parallel to the propagation direction of the ovipositor, and one perpendicular to it. The direction-dependent biomechanics of the locust major, dorsal digging valves are quantified and analyzed, under forces in the physiological range and beyond, considering hydration level, as well as the females’ age, or sexual maturation state. Our findings reveal that the responses of the valves to compression forces in the specific directions change upon sexual maturation to follow their function, and depend on environmental conditions. Namely, in the physiological force range, the valves are resistant to mechanical failure. In addition, mature females, which lay eggs, have stiffer valves, up to roughly nineteen times the stiffness of the pre-mature locusts. The valves are stiffer in the major working direction, corresponding to soil shuffling and compression, compared to the direction of propagation. Hydration of the valves reduces their stiffness but increases their resilience against failure. These findings provide mechanical and materials guidelines for the design of novel non-drilling excavating tools, including 3D-printed anisotropic materials based on composites.Statement of significance The female locust lay its eggs underground in order to protect them from predators and to provide them with optimal conditions for hatching. In order to dig into the ground, it uses two pairs of valves: The ventral pair is plugged as a wedge, while the dorsal pair performs the digging of the oviposition tunnel. We study the mechanical response of the digging valves, depending on age, hydration level and direction of operation. Our findings show that during the course of roughly two weeks in the life of the adult female, the digging valves become up to nineteen-fold stiffer against failure, in order to fulfill their function as diggers. While hydration reduces the stiffness, it also increases the resilience against failure and renders the valves unbreakable within the estimated physiological force range and beyond. The digging valves are consistently stiffer in the digging direction than in the perpendicular direction, implying on their form-follows-function design.Competing Interest StatementThe authors have declared no competing interest

Heat-mediated micro- and nano-pore evolution in sea urchin biominerals

Biomineralized structures with intricate shapes and morphologies, such as sea urchin skeletal elements, grow via the deposition of hydrated amorphous calcium carbonate (ACC) particles that subsequently crystallizes into single-crystalline calcite. This process is accompanied by volume changes due to density differences between the initial and final mineral state as well as variations in hydration levels. For this reason, the presence of macroporosity in synthetic systems was shown to be pivotal in the formation of large single crystals through ACC precursors. However, the role of macroporosity down to nanoporosity in the formation of biogenic minerals remains unknown. Here, we investigate the micro- and nano-porosity as well as the evolution of internal interfaces in the spines and test plates of Paracentrotus lividus sea urchins during the heat-mediated crystallization of remnant ACC and the destruction of intracrystalline organic molecules, using SEM, FIB-SEM, and in situ heating synchrotron SAXS measurements. We show the presence of nanopores likely filled with hydrated organics and visualize the evolution of nano- to micro-pores induced by heating, which may serve to accommodate the volume changes between amorphous and crystalline phases. The obtained results analyzed using thermodynamical considerations suggest that the growth in size of the nanopores is controlled by Ostwald ripening and is well described in the framework of classical pore coarsening theories. The extracted activation energies manifest that nanopore coarsening in the test plates is governed by surface diffusion, whereas in the spines by bulk diffusion. We suggest that such striking differences in diffusion mechanisms are caused by dissimilar levels of macroporosity and distributions of nano- and micro-internal interfaces in pristine biominerals

Wear mechanics of the female locust digging valves : the “good enough” principle

Adult female desert locusts (Schistocerca gregaria) dig underground to lay their eggs, ensuring optimal conditions for successful hatching. Digging is performed using the two pairs of oviposition valves at the tip of the female's abdomen. These valves are subjected to considerable shear forces during the repeated digging cycles, potentially leading to wear over time. The resilience of the valves is investigated by analyzing the relationship between digging experience and valve damage and wear throughout the female locust's life. The findings reveal the ability of the valves to withstand the significant shear forces encountered during digging. Despite this resilience, however, perceptible limitations in the valves’ mechanical durability against wear are observed. Toward the end of the female locust's life, the valves show substantial signs of wear, indicating effective performance but with limited longevity, i.e., a designated life span that enables successful oviposition for ca. four oviposition cycles. A comparison of the valve material with that of the animals’ mandibles, which are used continuously throughout their life and show remarkable wear-resistance, further highlights the evolutionary adaptation of the valve materials to their specific function, suggesting a trade-off between energetic investment and the sufficient, or “good-enough”, performance that is required for survival

Immunotherapeutic Blockade of Macrophage Clever-1 Reactivates the CD8(+) T-cell Response against Immunosuppressive Tumors

Purpose: As foremost regulators of cancer-related inflammation and immunotherapeutic resistance, tumor-associated macrophages have garnered major interest as immunotherapeutic drug targets. However, depletory strategies have yielded little benefit in clinical studies to date. An alternative approach is to exploit macrophage plasticity and "reeducate" tumorigenic macrophages toward an immunostimulatory phenotype to activate the host's antitumor immunity.Experimental Design: We investigated the role of the macrophage scavenger receptor common lymphatic endothelial and vascular endothelial receptor-1 (Clever-1) on tumor growth in multiple mouse cancer models with inflammatory and noninflammatory characteristics by using conditional knockouts, bone marrow chimeras, and cell depletion experiments. In addition, the efficacy of immunotherapeutic Clever-1 blockade as monotherapy or in combination with anti-PD-1 was tested.Results: Genetic deficiency of macrophage Clever-1 markedly impaired solid tumor growth. This effect was mediated by macrophages that became immunostimulatory in the absence of Clever-1, skewing the suppressive tumor microenvironment toward inflammation and activating endogenous antitumor CD8 thorn T cells. Comparable effects were achieved with immunotherapeutic blockade of Clever-1. Notably, these effects were similar to those achieved by PD-1 checkpoint inhibition. Moreover, combining anti-Clever-1 with anti-PD-1 provided synergistic benefit in aggressive, nonresponsive tumors.Conclusions: These findings demonstrate the importance of macrophages in mediating antitumor immune responses and support the clinical evaluation of immunotherapeutic Clever-1 blockade as a novel cancer treatment strategy.</div