Lysophosphatidylcholine Regulates Sexual Stage Differentiation in the Human Malaria Parasite Plasmodium falciparum.

Transmission represents a population bottleneck in the Plasmodium life cycle and a key intervention target of ongoing efforts to eradicate malaria. Sexual differentiation is essential for this process, as only sexual parasites, called gametocytes, are infective to the mosquito vector. Gametocyte production rates vary depending on environmental conditions, but external stimuli remain obscure. Here, we show that the host-derived lipid lysophosphatidylcholine (LysoPC) controls P. falciparum cell fate by repressing parasite sexual differentiation. We demonstrate that exogenous LysoPC drives biosynthesis of the essential membrane component phosphatidylcholine. LysoPC restriction induces a compensatory response, linking parasite metabolism to the activation of sexual-stage-specific transcription and gametocyte formation. Our results reveal that malaria parasites can sense and process host-derived physiological signals to regulate differentiation. These data close a critical knowledge gap in parasite biology and introduce a major component of the sexual differentiation pathway in Plasmodium that may provide new approaches for blocking malaria transmission.

Environmental alkalization suppresses deployment of virulence strategies in Pseudomonas syringae pv. tomato DC3000.

Plant pathogenic bacteria encounter a drastic increase in apoplastic pH during the early stages of plant immunity. The effects of alkalization on pathogen-host interactions have not been comprehensively characterized. Here, we used a global transcriptomic approach to assess the impact of environmental alkalization on Pseudomonas syringae pv. tomato DC3000 in vitro. In addition to the Type 3 Secretion System, we found expression of genes encoding other virulence factors such as iron uptake and coronatine biosynthesis to be strongly affected by environmental alkalization. We also found that the activity of AlgU, an important regulator of virulence gene expression, was induced at pH 5.5 and suppressed at pH 7.8, which are pH levels that this pathogen would likely experience before and during pattern-triggered immunity, respectively. This pH-dependent control requires the presence of periplasmic proteases, AlgW and MucP, that function as part of the environmental sensing system that activates AlgU in specific conditions. This is the first example of pH-dependency of AlgU activity, suggesting a regulatory pathway model where pH affects the proteolysis-dependent activation of AlgU. These results contribute to deeper understanding of the role apoplastic pH has on host-pathogen interactions.IMPORTANCEPlant pathogenic bacteria, like Pseudomonas syringae, encounter many environmental changes including oxidative stress and alkalization during plant immunity, but the ecological effects of the individual responses are not well understood. In this study, we found that transcription of many previously characterized virulence factors in P. syringae pv. tomato DC3000 is downregulated by the level of environmental alkalization these bacteria encounter during the early stages of plant immune activation. We also report for the first time the sigma factor AlgU is post-translationally activated by low environmental pH through its natural activation pathway, which partially accounts for the expression Type 3 Secretion System virulence genes at acidic pH. The results of this study demonstrate the importance of extracellular pH on global regulation of virulence-related gene transcription in plant pathogenic bacteria.

Diversity of function and higher-order structure within HWE sensor histidine kinases.

Integral to the protein structure/function paradigm, oligomeric state is typically conserved along with function across evolution. However, notable exceptions such as the hemoglobins show how evolution can alter oligomerization to enable new regulatory mechanisms. Here, we examine this linkage in histidine kinases (HKs), a large class of widely distributed prokaryotic environmental sensors. While the majority of HKs are transmembrane homodimers, members of the HWE/HisKA2 family can deviate from this architecture as exemplified by our finding of a monomeric soluble HWE/HisKA2 HK (EL346, a photosensing light-oxygen-voltage [LOV]-HK). To further explore the diversity of oligomerization states and regulation within this family, we biophysically and biochemically characterized multiple EL346 homologs and found a range of HK oligomeric states and functions. Three LOV-HK homologs are primarily dimeric with differing structural and functional responses to light, while two Per-ARNT-Sim-HKs interconvert between differentially active monomers and dimers, suggesting dimerization might control enzymatic activity for these proteins. Finally, we examined putative interfaces in a dimeric LOV-HK, finding that multiple regions contribute to dimerization. Our findings suggest the potential for novel regulatory modes and oligomeric states beyond those traditionally defined for this important family of environmental sensors.

Substantial gene expression shifts during larval transitions in the pearl oyster Pinctada margaritifera.

Early development stages in marine bivalve are critical periods where larvae transition from pelagic free-life to sessile mature individuals. The successive metamorphosis requires the expression of key genes, the functions of which might be under high selective pressure, hence understanding larval development represents key knowledge for both fundamental and applied research. Phenotypic larvae development is well known, but the underlying molecular mechanisms such as associated gene expression dynamic and molecular cross-talks remains poorly described for several nonmodel species, such as P. margaritifera. We designed a whole transcriptome RNA-sequencing analysis to describe such gene expression dynamics following four larval developmental stages:  d-shape, Veliger, Umbo and Eye-spot. Larval gene expression and annotated functions drastically diverge. Metabolic function (gene expression related to lipid, amino acid and carbohydrate use) is highly upregulated in the first development stages, with increasing demand from  d-shape to umbo. Morphogenesis and larval transition are partly ordered by Thyroid hormones and Wnt signaling. While larvae shells show some similar characteristic to adult shells, the cause of initialization of biomineralization differ from the one found in adults. The present study provides a global overview of Pinctada margaritifera larval stages transitioning through gene expression dynamics, molecular mechanisms and ontogeny of biomineralization, immune system, and sensory perception processes.

Comprehensive Assessment of Context-Adaptive Street Lighting: Technical Aspects, Economic Insights, and Measurements from Large-Scale, Long-Term Implementations.

This paper addresses the growing importance of efficient street lighting management, driven by rising electricity costs and the need for municipalities to implement cost-effective solutions. Central to this study is the UNI 11248 Italian regulation, which extends the European EN 13201-1 standard introduced in 2016. These standards provide guidelines for designing, installing, operating, and maintaining lighting systems in pedestrian and vehicular traffic areas. Specifically, the UNI 11248 standard introduces the possibility to dynamically adjust light intensity through two alternative operating modes: (a) Traffic Adaptive Installation (TAI), which dims the light based solely on real-time traffic flow measurements; and (b) Full Adaptive Installation (FAI), which, in addition to traffic measurements, also requires evaluating road surface luminance and meteorological conditions. In this paper, we first present the general architecture and operation of an FAI-enabled lighting infrastructure, which relies on environmental sensors and a heterogeneous wireless communication network to connect intelligent, remotely controlled streetlights. Subsequently, we examine large-scale, in-field FAI infrastructures deployed in Vietnam and Italy as case studies, providing substantial measurement data. The paper offers insights into the measured energy consumption of these infrastructures, comparing them to that of conventional light-control strategies used in traditional installations. The measurements demonstrate the superiority of FAI as the most efficient solution.

Loom: A Modular Open-Source Approach to Rapidly Produce Sensor, Actuator, Datalogger Systems.

In the face of rising population, erratic climate, resource depletion, and increased exposure to natural hazards, environmental monitoring is increasingly important. Satellite data form most of our observations of Earth. On-the-ground observations based on in situ sensor systems are crucial for these remote measurements to be dependable. Providing open-source options to rapidly prototype environmental datalogging systems allows quick advancement of research and monitoring programs. This paper introduces Loom, a development environment for low-power Arduino-programmable microcontrollers. Loom accommodates a range of integrated components including sensors, various datalogging formats, internet connectivity (including Wi-Fi and 4G Long Term Evolution (LTE)), radio telemetry, timing mechanisms, debugging information, and power conservation functions. Additionally, Loom includes unique applications for science, technology, engineering, and mathematics (STEM) education. By establishing modular, reconfigurable, and extensible functionality across components, Loom reduces development time for prototyping new systems. Bug fixes and optimizations achieved in one project benefit all projects that use Loom, enhancing efficiency. Although not a one-size-fits-all solution, this approach has empowered a small group of developers to support larger multidisciplinary teams designing diverse environmental sensing applications for water, soil, atmosphere, agriculture, environmental hazards, scientific monitoring, and education. This paper not only outlines the system design but also discusses alternative approaches explored and key decision points in Loom's development.

Fusion of Environmental Sensors for Occupancy Detection in a Real Construction Site.

Internet-of-Things systems are increasingly being installed in buildings to transform them into smart ones and to assist in the transition to a greener future. A common feature of smart buildings, whether commercial or residential, is environmental sensing that provides information about temperature, dust, and the general air quality of indoor spaces, assisting in achieving energy efficiency. Environmental sensors though, especially when combined, can also be used to detect occupancy in a space and to increase security and safety. The most popular methods for the combination of environmental sensor measurements are concatenation and neural networks that can conduct fusion in different levels. This work presents an evaluation of the performance of multiple late fusion methods in detecting occupancy from environmental sensors installed in a building during its construction and provides a comparison of the late fusion approaches with early fusion followed by ensemble classifiers. A novel weighted fusion method, suitable for imbalanced samples, is also tested. The data collected from the environmental sensors are provided as a public dataset.

Environmental Sensing in High-Altitude Mountain Ecosystems Powered by Sedimentary Microbial Fuel Cells.

The increasing need for fresh water in a climate change scenario requires remote monitoring of water bodies in high-altitude mountain areas. This study aimed to explore the feasibility of SMFC operation in the presence of low dissolved oxygen concentrations for remote, on-site monitoring of physical environmental parameters in high-altitude mountainous areas. The implemented power management system (PMS) uses a reference SMFC (SMFCRef) to implement a quasi-maximum power point tracking (quasi-MPPT) algorithm to harvest energy stably. As a result, while transmitting in a point-to-point wireless sensor network topology, the system achieves an overall efficiency of 59.6%. Furthermore, the control mechanisms prevent energy waste and maintain a stable voltage despite the microbial fuel cell (MFC)'s high impedance, low time response, and low energy production. Moreover, our system enables a fundamental understanding of environmental systems and their resilience of adaptation strategies by being a low-cost, ecological, and environmentally friendly alternative to power-distributed and dynamic environmental sensing networks in high-altitude mountain ecosystems with anoxic environmental conditions.

Environmental sensing and regulation of motility in Toxoplasma.

Toxoplasma and other apicomplexan parasites undergo a unique form of cellular locomotion referred to as "gliding motility." Gliding motility is crucial for parasite survival as it powers tissue dissemination, host cell invasion and egress. Distinct environmental cues lead to activation of gliding motility and have become a prominent focus of recent investigation. Progress has been made toward understanding what environmental cues are sensed and how these signals are transduced in order to regulate the machinery and cellular events powering gliding motility. In this review, we will discuss new findings and integrate these into our current understanding to propose a model of how environmental sensing is achieved to regulate gliding motility in Toxoplasma. Collectively, these findings also have implications for the understanding of gliding motility across Apicomplexa more broadly.

Emissions of nitrogen dioxide in the northeast U.S. during the 2020 COVID-19 lockdown.

We have quantified the emissions of Nitrogen dioxide (NO2) in the Northeast megalopolis of the United States during the COVID-19 lockdown. The measurement of NO2 emission serves as the indicator for the emission of the group of nitrogen oxides (NOx). Approximately 56% of NO2 emissions in the US are from mobile sources, and the remainder is from stationary sources. Since 2002, clean air regulations have resulted in approximately 5% compound annual reduction of NOx emissions in the US (8.2% in the study area). Therefore, when studying the impact of sporadic events like an epidemic on emissions, it is necessary to account for the persistent reduction of emissions due to policy driven emission reduction measures. Using spaceborne sensors, ground monitors, National Emission Inventory data, and the US Motor Vehicle Emission Simulator, we quantified the reduction of total NOx emissions, distinguishing stationary sources from on-road mobile sources (trucks and automobiles). When considering total NOx emissions (stationary and mobile combined), we find that the pandemic restrictions resulted in 3.4% reduction of total NOx emissions in the study area in 2020. This is compared to (and in addition to) the expected 8.2% policy driven reduction of NOx emissions in 2020. This somewhat low reduction of emissions is because most stationary sources (factories, power plants, etc.) were operational during the pandemic. Truck traffic, a significant source of mobile emissions, also did not decline significantly (average 4.8% monthly truck traffic reduction in the study area between March and August 2020), as they were delivering goods during the lockdown. On the other hand, automobile traffic, responsible for 24% of total NOx emissions, dropped significantly, 52% in April, returning to near normal after 5 months. While the reduction of automobile traffic was significant, especially in the early months of the pandemic, its effect on emissions was relatively insignificant.

Structural asymmetry does not indicate hemiphosphorylation in the bacterial histidine kinase CpxA.

Histidine protein kinases (HKs) are prevalent prokaryotic sensor kinases that are central to phosphotransfer in two-component signal transduction systems, regulating phosphorylation of response regulator proteins that determine the output responses. HKs typically exist as dimers and can potentially autophosphorylate at each conserved histidine residue in the individual protomers, leading to diphosphorylation. However, analyses of HK phosphorylation in biochemical assays in vitro suggest negative cooperativity, whereby phosphorylation in one protomer of the dimer inhibits phosphorylation in the second protomer, leading to ∼50% phosphorylation of the available sites in dimers. This negative cooperativity is often correlated with an asymmetric domain arrangement, a common structural characteristic of autophosphorylation states in many HK structures. In this study, we engineered covalent dimers of the cytoplasmic domains of Escherichia coli CpxA, enabling us to quantify individual species: unphosphorylated, monophosphorylated, and diphosphorylated dimers. Together with mathematical modeling, we unambiguously demonstrate no cooperativity in autophosphorylation of CpxA despite its asymmetric structures, indicating that these asymmetric domain arrangements are not linked to negative cooperativity and hemiphosphorylation. Furthermore, the modeling indicated that many parameters, most notably minor amounts of ADP generated during autophosphorylation reactions or present in ATP preparations, can produce ∼50% total phosphorylation that may be mistakenly attributed to negative cooperativity. This study also establishes that the engineered covalent heterodimer provides a robust experimental system for investigating cooperativity in HK autophosphorylation and offers a useful tool for testing how symmetric or asymmetric structural features influence HK functions.

Structural insights into emergent signaling modes of G protein-coupled receptors.

G protein-coupled receptors (GPCRs) represent the largest family of cell membrane proteins, with >800 GPCRs in humans alone, and recognize highly diverse ligands, ranging from photons to large protein molecules. Very important to human medicine, GPCRs are targeted by about 35% of prescription drugs. GPCRs are characterized by a seven-transmembrane α-helical structure, transmitting extracellular signals into cells to regulate major physiological processes via heterotrimeric G proteins and ß-arrestins. Initially viewed as receptors whose signaling via G proteins is delimited to the plasma membrane, it is now recognized that GPCRs signal also at various intracellular locations, and the mechanisms and (patho)physiological relevance of such signaling modes are actively investigated. The propensity of GPCRs to adopt different signaling modes is largely encoded in the structural plasticity of the receptors themselves and of their signaling complexes. Here, we review emerging modes of GPCR signaling via endosomal membranes and the physiological implications of such signaling modes. We further summarize recent structural insights into mechanisms of GPCR activation and signaling. We particularly emphasize the structural mechanisms governing the continued GPCR signaling from endosomes and the structural aspects of the GPCR resensitization mechanism and discuss the recently uncovered and important roles of lipids in these processes.

Spatiotemporal patterns of intracellular Ca2+ signalling govern hypo-osmotic stress resilience in marine diatoms.

Diatoms are globally important phytoplankton that dominate coastal and polar-ice assemblages. These environments exhibit substantial changes in salinity over dynamic spatiotemporal regimes. Rapid sensory systems are vital to mitigate the harmful consequences of osmotic stress. Population-based analyses have suggested that Ca2+ signalling is involved in diatom osmotic sensing. However, mechanistic insight of the role of osmotic Ca2+ signalling is limited. Here, we show that Phaeodactylum Ca2+ elevations are essential for surviving hypo-osmotic shock. Moreover, employing novel single-cell imaging techniques we have characterised real-time Ca2+ signalling responses in single diatom cells to environmental osmotic perturbations. We observe that intracellular spatiotemporal patterns of osmotic-induced Ca2+ elevations encode vital information regarding the nature of the osmotic stimulus. Localised Ca2+ signals evoked by mild or gradual hypo-osmotic shocks are propagated globally from the apical cell tips, enabling fine-tuned cell volume regulation across the whole cell. Finally, we demonstrate that diatoms adopt Ca2+ -independent and dependent mechanisms for osmoregulation. We find that efflux of organic osmolytes occurs in a Ca2+ -independent manner, but this response is insufficient to mitigate cell damage during hypo-osmotic shock. By comparison, Ca2+ -dependent signalling is necessary to prevent cell bursting via precise coordination of K+ transport, and therefore is likely to underpin survival in dynamic osmotic environments.

The role of two-component regulatory systems in environmental sensing and virulence in Salmonella.

Adaptation to environments with constant fluctuations imposes challenges that are only overcome with sophisticated strategies that allow bacteria to perceive environmental conditions and develop an appropriate response. The gastrointestinal environment is a complex ecosystem that is home to trillions of microorganisms. Termed microbiota, this microbial ensemble plays important roles in host health and provides colonization resistance against pathogens, although pathogens have evolved strategies to circumvent this barrier. Among the strategies used by bacteria to monitor their environment, one of the most important are the sensing and signalling machineries of two-component systems (TCSs), which play relevant roles in the behaviour of all bacteria. Salmonella enterica is no exception, and here we present our current understanding of how this important human pathogen uses TCSs as an integral part of its lifestyle. We describe important aspects of these systems, such as the stimuli and responses involved, the processes regulated, and their roles in virulence. We also dissect the genomic organization of histidine kinases and response regulators, as well as the input and output domains for each TCS. Lastly, we explore how these systems may be promising targets for the development of antivirulence therapeutics to combat antibiotic-resistant infections.

Technological opportunities for sensing of the health effects of weather and climate change: a state-of-the-art-review.

Sensing and measuring meteorological and physiological parameters of humans, animals, and plants are necessary to understand the complex interactions that occur between atmospheric processes and the health of the living organisms. Advanced sensing technologies have provided both meteorological and biological data across increasingly vast spatial, spectral, temporal, and thematic scales. Information and communication technologies have reduced barriers to data dissemination, enabling the circulation of information across different jurisdictions and disciplines. Due to the advancement and rapid dissemination of these technologies, a review of the opportunities for sensing the health effects of weather and climate change is necessary. This paper provides such an overview by focusing on existing and emerging technologies and their opportunities and challenges for studying the health effects of weather and climate change on humans, animals, and plants.

Biomimetic Sensors to Detect Bioanalytes in Real-Life Samples Using Molecularly Imprinted Polymers: A Review.

Molecularly imprinted polymers (MIPs) come with the promise to be highly versatile, useful artificial receptors for sensing a wide variety of analytes. Despite a very large body of literature on imprinting, the number of papers addressing real-life biological samples and analytes is somewhat limited. Furthermore, the topic of MIP-based sensor design is still, rather, in the research stage and lacks wide-spread commercialization. This review summarizes recent advances of MIP-based sensors targeting biological species. It covers systems that are potentially interesting in medical applications/diagnostics, in detecting illicit substances, environmental analysis, and in the quality control of food. The main emphasis is placed on work that demonstrates application in real-life matrices, including those that are diluted in a reasonable manner. Hence, it does not restrict itself to the transducer type, but focusses on both materials and analytical tasks.

Molecularly Imprinted Polymers (MIPs) in Sensors for Environmental and Biomedical Applications: A Review.

Molecular imprinted polymers are custom made materials with specific recognition sites for a target molecule. Their specificity and the variety of materials and physical shapes in which they can be fabricated make them ideal components for sensing platforms. Despite their excellent properties, MIP-based sensors have rarely left the academic laboratory environment. This work presents a comprehensive review of recent reports in the environmental and biomedical fields, with a focus on electrochemical and optical signaling mechanisms. The discussion aims to identify knowledge gaps that hinder the translation of MIP-based technology from research laboratories to commercialization.

Environmental sensing and morphological plasticity in plants.

All creatures on earth are affected by their surrounding environment. Animals can move and escape unfavorable environmental changes, whereas plants must respond to environmental stimuli. Plants adapt to changes with cellular-level responses to short-term environmental changes, but may adapt to changes in the environment by regulating their development and growth. In this review, we considered changes in atmospheric CO2 concentrations, dry/wet moisture conditions, flooding, and temperature as examples of environmental stimuli. We mainly focused on leaf morphology and stomatal density as examples of developmental and growth patterns of plants in response to the environment.

Application of molecular SERS nanosensors: where we stand and where we are headed towards?

Molecular specific and highly sensitive detection is the driving force of the surface-enhanced Raman spectroscopy (SERS) community. The technique opens the window to the undisturbed monitoring of cellular processes in situ or to the quantification of small molecular species that do not deliver Raman signals. The smart design of molecular SERS nanosensors makes it possible to indirectly but specifically detect, e.g. reactive oxygen species, carbon monoxide or potentially toxic metal ions. Detection schemes evolved over the years from simple metallic colloidal nanoparticles functionalized with sensing molecules that show uncontrolled aggregation to complex nanostructures with magnetic properties making the analysis of complex environmental samples possible. The present article gives the readership an overview of the present research advancements in the field of molecular SERS sensors, highlighting future trends.

Characterization of additional components of the environmental pH-sensing complex in the pathogenic fungus Cryptococcus neoformans.

Pathogenic microorganisms must adapt to changes in their immediate surroundings, including alterations in pH, to survive the shift from the external environment to that of the infected host. In the basidiomycete fungal pathogen Cryptococcus neoformans, these pH changes are primarily sensed by the fungus-specific, alkaline pH-sensing Rim/Pal pathway. The C. neoformans Rim pathway has diverged significantly from that described in ascomycete fungi. We recently identified the C. neoformans putative pH sensor Rra1, which activates the Rim pathway in response to elevated pH. In this study, we probed the function of Rra1 by analyzing its cellular localization and performing protein co-immunoprecipitation to identify potential Rra1 interactors. We found that Rra1 does not strongly colocalize or interact with immediate downstream Rim pathway components. However, these experiments identified a novel Rra1 interactor, the previously uncharacterized C. neoformans nucleosome assembly protein 1 (Nap1), which was required for Rim pathway activation. We observed that Nap1 specifically binds to the C-terminal tail of the Rra1 sensor, probably promoting Rra1 protein stability. This function of Nap1 is conserved in fungi closely related to C. neoformans that contain Rra1 orthologs, but not in the more distantly related ascomycete fungus Saccharomyces cerevisiae In conclusion, our findings have revealed the sophisticated, yet distinct, molecular mechanisms by which closely and distantly related microbial phyla rapidly adapt to environmental signals and changes, such as alterations in pH.