Search Results (145)

Extreme environments, such as hypersaline habitats, hot springs, deep-sea hydrothermal vents, glaciers, and permafrost, provide diverse ecological niches for studying microbial evolution. However, knowledge of microbial communities in extreme environments at high southern latitudes remains limited, aside from Antarctica. Laguna Timone is a hypersaline crater lake located in a Pleistocene maar of the Pali Aike Volcanic Field, southern Patagonia; the lake was formed during basaltic eruptions in a periglacial setting. Here, we report the first integrative characterization of microbial communities from biofilms and microbial mats in this lake using high-throughput 16S rRNA and ITS gene sequencing, along with mineralogical and hydrochemical analyses of water, sediments, and carbonates. Bacterial communities were dominated by the genera Enterobacterales ASV1, Pseudomonas, Oscillatoria, Nodularia, and Belliella, with site-specific assemblages. Fungal communities included Laetinaevia, Ilyonectria, Thelebolus, Plectosphaerella, and Acrostalagmus, each showing distinct distribution patterns. These baseline data contribute to understanding microbial dynamics in hypersaline maar environments and support future investigations. This integrative approach highlights key microbe–mineral relationships and underscores the potential of Laguna Timone as a natural laboratory for exploring biosignature formation and microbial adaptation in chemically extreme environments, both on early Earth and potentially beyond. Full article

Depression represents one of the most prevalent mental health disorders globally, significantly impacting quality of life and posing substantial healthcare challenges. Traditional diagnostic methods rely on subjective assessments and clinical interviews, often leading to misdiagnosis, delayed treatment, and suboptimal outcomes. Recent advances in biosensing technologies offer promising avenues for objective depression assessment through detection of relevant biomarkers and physiological parameters. This review examines multi-modal biosensing approaches for depression by analyzing electrochemical biosensors for neurotransmitter monitoring alongside wearable sensors tracking autonomic, neural, and behavioral parameters. We explore sensor fusion methodologies, temporal dynamics analysis, and context-aware frameworks that enhance monitoring accuracy through complementary data streams. The review discusses clinical validation across diagnostic, screening, and treatment applications, identifying performance metrics, implementation challenges, and ethical considerations. We outline technical barriers, user acceptance factors, and data privacy concerns while presenting a development roadmap for personalized, continuous monitoring solutions. This integrative approach holds significant potential to revolutionize depression care by enabling earlier detection, precise diagnosis, tailored treatment, and sensitive monitoring guided by objective biosignatures. Successful implementation requires interdisciplinary collaboration among engineers, clinicians, data scientists, and end-users to balance technical sophistication with practical usability across diverse healthcare contexts. Full article

We present a corrosion-resistant quadrupole ion trap mass spectrometer (QIT-MS) designed for trace detection of volatiles in sulfuric acid aerosols, with a specific focus on phosphine (PH₃). Here, we detail the gas calibration methodology using permeation tube technology for generating certified ppb-level PH₃/H₂S/CO₂ mixtures, and report results from mass spectra with sufficient resolution to distinguish isotopic envelopes that validate the detection of PH₃ at a concentration of 62 ppb. Fragmentation patterns for PH₃ and H₂S agree with NIST data, and signal-to-noise performance confirms ppb sensitivity over 2.6 h acquisition periods. We further assess spectral interferences from oxygen isotopes and propose a detection scheme based on isolated phosphorus ions (P⁺) to enable specific and interference-resistant identification of PH₃ and other reduced phosphorus species of astrobiological interest in Venus-like environments. This work extends the capabilities of QIT-MS for trace gas analysis in chemically aggressive atmospheric conditions. Full article

Background: In just twenty years, three dangerous human coronaviruses—SARS-CoV, MERS-CoV, and SARS-CoV-2 have exposed critical gaps in early detection of emerging viral threats. Current diagnostics remain pathogen-focused, often missing the earliest phase of infection. A virus-agnostic, host-based diagnostic capable of detecting responses to viral intrusion is urgently needed. Methods: We hypothesized that the lungs act as biomechanical instruments, with infection altering tissue tension, wave propagation, and flow dynamics in ways detectable through subaudible vibroacoustic signals. In a matched case–control study, we enrolled 19 RT-PCR-confirmed COVID-19 inpatients and 16 matched controls across two Johns Hopkins hospitals. Multimodal data were collected, including passive vibroacoustic auscultation, lung ultrasound, peak expiratory flow, and laboratory markers. Machine learning models were trained to identify host-response biosignatures from anterior chest recordings. Results: 19 COVID-19 inpatients and 16 matched controls (mean BMI 32.4 kg/m², mean age 48.6 years) were successfully enrolled to the study. The top-performing, unoptimized, vibroacoustic-only model achieved an AUC of 0.84 (95% CI: 0.67–0.92). The host-covariate optimized model achieved an AUC of 1.0 (95% CI: 0.94–1.0), with 100% sensitivity (95% CI: 82–100%) and 99.6% specificity (95% CI: 85–100%). Vibroacoustic data from the anterior chest alone reliably distinguished COVID-19 cases from controls. Conclusions: This proof-of-concept study demonstrates that passive, noninvasive vibroacoustic biosignatures can detect host response to viral infection in a hospitalized population and supports further testing of this modality in broader populations. These findings support the development of scalable, host-based diagnostics to enable early, agnostic detection of future pandemic threats (ClinicalTrials.gov number: NCT04556149). Full article

Understanding the mechanisms of protein preservation in extreme environments is essential for identifying potential molecular biosignatures on Mars. In this study, we investigated five sabkha sedimentary samples from the Abu Dhabi coast, spanning from the present day to ~11,000 years before present (BP), to assess how mineralogy and environmental conditions influence long-term protein stability. Using LC-MS/MS and direct Data-independent Acquisition (DIA) proteomic analysis, we identified 722 protein groups and 1300 peptides, revealing a strong correlation between preservation and matrix composition. Carbonate- and silica-rich samples favored the retention of DNA-binding and metal-coordinating proteins via mineral–protein interactions, while halite- and gypsum-dominated facies showed lower recovery due to extreme salinity and reduced biomass input. Functional profiling revealed a shift from metabolic dominance in modern samples to genome maintenance strategies in ancient ones, indicating microbial adaptation to prolonged environmental stress. Contrary to expectations, some ancient samples preserved large, multi-domain proteins, suggesting that early mineral encapsulation can stabilize structurally complex biomolecules over millennial timescales. Taxonomic reconstruction based on preserved proteins showed broad archaeal diversity, including Thaumarchaeota and thermophilic lineages, expanding our understanding of microbial ecology in hypersaline systems. These findings highlight sabkhas as valuable analogs for Martian evaporitic environments and suggest that carbonate–silica matrices on Mars may offer optimal conditions for preserving ancient molecular traces of life. Full article

Transthyretin (TTR) variant (V30M) polyneuropathy (ATTRv-PN) is a progressive systemic amyloidosis caused by transthyretin aggregation, leading to a variety of debilitating manifestations, including neuropathy and cardiomyopathy. We investigated the plasma proteome of heterozygotic V30M TTR asymptomatic carriers and heterozygotic V30M ATTRv-PN patients (before and after tafamidis treatment) versus WT TTR healthy control plasma using an organic solvent-induced shift in solubility assay to identify biosignatures for disease progression and therapeutic response. We identified many proteins, including TTR, apolipoproteins, ceruloplasmin, and proteins with functions in innate immunity that displayed changes in either their abundances or their sensitivity to precipitation. Elevated oxidative modifications of TTR and APOE in ATTRv-PN patients suggest a role for oxidative stress in disease pathogenesis/progression. Tafamidis treatment mitigated these pathology-associated changes, suggesting that alleviating proteotoxic stress impacts these other pathways. Although our study was limited to a Portuguese cohort, these findings nevertheless provide a comprehensive plasma proteomic profile of V30M ATTRv-PN patients, V30M TTR carriers, and tafamidis-treated ATTRv-PN patients over up to 60 months; provide insights into ATTRv-PN pathophysiology; identify potential biomarkers for disease progression and therapeutic response; and highlight the utility of proteomics in advancing personalized treatments for amyloidosis. Full article

We present a corrosion-resistant quadrupole ion trap mass spectrometer (QIT-MS) for the direct detection of biosignature gasses in chemically reactive planetary atmospheres, such as Venusian clouds. The system employs a Paul trap with hyperbolic titanium alloy electrodes and alumina spacers for chemical durability and precise ion confinement. An yttria-coated iridium filament serves as the thermionic emitter within a modular electron gun capable of axial and radial ionization. Analytes are introduced through fused silica capillaries and crescent inlets into a miniature pressure cell. The testbed integrates high-voltage RF electronics, pressure-regulated sample delivery, and FPGA-based control for real-time tuning. Continuous operation in 98% sulfuric acid vapor for over three months demonstrated no degradation in emitter or sensor performance. Mass spectra revealed H₂SO₄ fragmentation and thermally induced decomposition up to 425 K. Spectral variations with filament current and electron energy highlight thermal and electron-induced dissociation dynamics. Operational modes include high-resolution scans and selective ion ejection (e.g., CO₂⁺, N₂⁺) to enhance the detection of PH₃⁺, H₂S⁺, and daughter ions. The compact QIT-MS platform is validated for future missions targeting corrosive atmospheres, enabling in situ astrobiological investigations through the detection of biosignature gasses such as phosphine and hydrogen sulfide. Full article

The Dead Sea is one of the most saline terminal lakes on Earth, and few organisms survive in this harsh environment. In some onshore spring pools, active and diverse microbial communities flourish. In the geological past, microbial-rich environments left their marks in the form of stromatolites. Stromatolites are studied to better understand the appearance of life on Earth and potentially on other planets. Hyperspectral methodologies have been shown to be useful for detecting structures in stromatolites. In an effort to characterize the biosignatures and chemical composition inherent to stromatolites, we created a spectral classification scheme for distinguishing between stromatolites and their bedrock environment—typically carbonatic rocks, mostly dolomites. The overarching aim comprises the development of an automated hyperspectral reflectance method for detecting the presence of stromatolites. We collected and measured 82 field samples with an ASD spectrometer and used our spectral dataset to train three machine learning algorithms (linear regression, K-Nearest Neighbor, XGBoost). The results show the successful detection of stromatolites, with all three prediction methods giving high accuracy rates (stromatolite > 0.9, bedrock dolomite > 0.8). The continuum removal and spectral ratio technique results identified two significant spectral regions, ~1900 nm (water) and ~2310–2320 nm (carbonates), that allow one to differentiate between stromatolites and dolomites. This study establishes the grounds for the automated detection of a fossilized livable environment in a carbonatic terrain based on its hyperspectral reflectance data. The results have significant implications for future mapping efforts and emphasize the feasibility of automated mapping, extending the data acquisition to airborne or satellite-based hyperspectral remote sensing technologies to detect life forms in extreme environments. Full article

The search for life beyond Earth currently hinges on the detection of biosignatures that are indicative of current or past life, with terrestrial life being the sole known example. Deoxyribonucleic acid (DNA), which acts as the long-term storage of genetic information in all known organisms, is considered a biosignature of life. Techniques like the Polymerase Chain Reaction (PCR) are particularly useful as they allow for the amplification of DNA fragments, allowing the detection of even trace amounts of genetic material. This study aimed to detect DNA extracted from colonies of an Antarctic black fungus both when (i) alone and (ii) mixed with a Sulfatic Mars Regolith Simulant (S-MRS), after exposure to increasing doses of Fe ions (up to 1 kGy). PCR-based amplification methods were used for detection. The findings of this study revealed no DNA amplification in samples mixed with Sulfatic Mars Regolith Simulant, providing important insights into the potential application of these techniques for in situ DNA detection during future space exploration missions or for their application on the Mars sample return program; it also gives input in the planetary protection discussions. Full article

The enrichment of trace metals and other life-essential elements, like phosphorus, in carbonates may be a signature of microbial life. Enrichments of such elements in microbial carbonate facies in the rock record have been attributed to life in previous studies, but the biologic origin of these enrichments is contentious. We experimentally tested the hypothesis that enrichments of life-important trace elements occur in both cells and carbonate minerals that form as a result of cellular photosynthesis for the cyanobacteria Synechococcus PCC 8806. We grew Synechococcus PCC 8806 and measured the trace element concentrations of the cells and the minerals that precipitate with the cells, and we compared the results to abiotically precipitated mineral material from the same growth medium conditions. We found that for all the tested trace elements (B, P, K, Mn, Fe, Co, Cu, and Zn, chosen for their requirements in the growth medium of Synechococcus PCC 8806 and known uses in cellular machinery), nearly all the sample types were enriched relative to the medium concentrations. The dominant pattern for most elements was that cells were the most enriched, followed by biotic minerals, and then abiotic minerals. However, this pattern was complicated by varying concentrations of Mg in the mineral samples because the data were normalized to Mg (Mg was the dominant cation in the solution next to Na). Nonetheless, however the data are normalized, Fe was the most enriched element in the cells and both the biotic and abiotic minerals relative to the medium concentrations. Fe had the largest enrichment factor (E.F.) for all the sample types, with an E.F. of approximately 2800 in the biotic minerals, 1620 in the cells, and 230 in the abiotic minerals. Fe was followed by Zn (E.F. of ~329 in cells, 198 in biotic minerals, and 78 in abiotic minerals), Cu (E.F. of ~424 in cells, 171 in biotic minerals, and 50 in abiotic minerals), Mn (E.F. of ~200 in cells, 95 in biotic minerals, and 53 in abiotic minerals), and P (E.F. of ~149 in cells, 37 in biotic minerals, and 6 in abiotic minerals), suggesting that these elements can be useful as biosignatures when used in combination with other evidence. Full article

Chloromethane (CH₃Cl) is a key chlorinated organic compound not only in atmospheric chemistry, but also in the field of molecular astrophysics and a possible biosignature in exoplanetary atmospheres. While the spectroscopic characterization of the main isotopic species has been addressed in great detail, that of its isotopologues remains incomplete. This work aims at filling this gap by focusing on the bideuterated species, CHD₂Cl, and exploiting both rotational and vibrational spectroscopy in combination with state-of-the-art quantum-chemical (QC) calculations. First, the rotational spectrum of CHD₂Cl has been measured in the millimeter-wave domain, allowing the accurate determination of several spectroscopic constants for four isotopologues, namely ¹²CHD₂³⁵Cl, ¹²CHD₂³⁷Cl, ¹³CHD₂³⁵Cl, and ¹³CHD₂³⁷Cl. The newly determined rotational constants have been used to refine the semi-experimental equilibrium structure of chloromethane. Secondly, the vibrational analysis, supported by high-level QC predictions of vibrational energies, has been conducted in the 500–6200 cm⁻¹ infrared (IR) region, enabling the identification of more than 30 bands including fundamental, overtone, and combination transitions. Finally, chloromethane’s radiative efficiency has been simulated using the QC IR absorption cross-sections, and the effects of isotopologue distribution on the predicted radiative properties have been investigated. All these findings greatly improve the comprehension of the spectroscopic properties of bideuterated chloromethane isotopologues, and of chloromethane in general, and facilitate future terrestrial and extraterrestrial studies. Full article

The unambiguous detection of biosignatures in exoplanet atmospheres is a primary objective for astrobiologists and exoplanet astronomers. The primary methodology is the observation of combinations of gases considered unlikely to coexist in an atmosphere or individual gases considered to be highly biogenic. Earth-like examples of the former include CH₄ and O₃, and the latter includes dimethyl sulfide (DMS). To improve the plausibility of the detection of life, I argue that the isotope ratios of key atmospheric species are needed. The C isotope ratios of CO₂ and CH₄ are especially valuable. On Earth, thermogenesis and volcanism result in a substantial difference in δ¹³C between atmospheric CH₄ and CO₂ of ~−25‰. This difference could have changed significantly, perhaps as large as −95‰ after the evolution of hydrogenotrophic methanogens. In contrast, nitrogen fixation by nitrogenase results in a relatively small difference in δ¹⁵N between N₂ and NH₃. Isotopic biosignatures on ancient Earth and rocky exoplanets likely coexist with much larger photochemical signatures. Extreme δ¹⁵N enrichment in HCN may be due to photochemical self-shielding in N₂, a purely abiotic process. Spin-forbidden photolysis of CO₂ produces CO with δ¹³C < −200‰, as has been observed in the Venus mesosphere. Self-shielding in SO₂ may generate detectable ³⁴S enrichment in SO in atmospheres similar to that of WASP-39b. Sufficiently precise isotope ratio measurements of these and related gases in terrestrial-type exoplanet atmospheres will require instruments with significantly higher spectral resolutions and light-collecting areas than those currently available. Full article

Metal species and carbonate are often found as minerals in extraterrestrial rocky bodies. Based on this, the mechanochemical-induced degradation of canonical purine and pyrimidine ribonucleosides into their corresponding nucleobases mediated by some of the main constituents of those materials (iron, nickel, or aluminum) was accomplished. In some cases, the previous heating of the samples intensified mechanochemical degradation. Additionally, carbonate acts as an activator for ribonucleoside degradation with a catalyst (a Lewis acid ion); however, it has almost no effect on ribonucleoside degradation in the absence of a catalyst. These results can contribute to the hypothesis that organic matter in extraterrestrial samples could have undergone mechanochemical reactions (i.e., shock/impact events), from its formation until its journey to Earth. Mechanochemical energy could occur in planetesimal accretion, asteroid formation (i.e., through planetesimal disintegration), and meteoroid atmospheric entry. Additionally, this hypothesis can clarify and relate some identified biosignatures with pathways of prebiological evolution. Full article

Few halophilic strains have been examined in detail for their culturability and metabolic activity at subzero temperatures, within the ice matrix, over the longer term. Here, we examine three Arctic strains with varied salinity tolerances: Colwellia psychrerythraea str. 34H (Cp34H), Psychrobacter sp. str. 7E (P7E), and Halomonas sp. str. 3E (H3E). As a proxy for biosignatures, we examine observable cells, metabolic activity, and recoverability on 12-month incubations at −5, −10 and −36 °C. To further develop life-detection strategies, we also study the short-term tracking of new protein synthesis on Cp34H at −5 °C for the first time, using isotopically labeled ¹³C₆-leucine and mass spectrometry-based proteomics. All three bacterial species remained metabolically active after 12 months at −5 °C, while recoverability varied greatly among strains. At −10 and −36 °C, metabolic activity was drastically reduced and recoverability patterns were strain-specific. Cells were observable at high numbers in all treatments, validating their potential as biosignatures. Newly synthesized proteins were detectable and identifiable after one hour of incubation. Proteins prioritized for synthesis with the provided substrate are involved in motility, protein synthesis, and in nitrogen and carbohydrate metabolism, with an emphasis on structural proteins, enzymatic activities in central metabolic pathways, and regulatory functions. Full article

Background: Sarcoidosis is a granulomatous disease affecting multiple organ systems and poses a diagnostic challenge due to its diverse clinical manifestations and absence of specific diagnostic tests. Currently, blood biomarkers such as ACE, sIL-2R, CD163, CCL18, serum amyloid A, and CRP are employed to aid in the diagnosis and monitoring of sarcoidosis. Metabolomics holds promise for identifying highly sensitive and specific biomarkers. This study aimed to leverage metabolomics for the early diagnosis of sarcoidosis and to identify metabolic phenotypes associated with disease progression. Methods: Serum samples from patients with sarcoidosis (n = 40, including stage 1 to stage 4), were analyzed for metabolite levels by semi-untargeted liquid chromatography–mass spectrometry (LC-MS). Metabolomics data from patients with sarcoidosis were compared with those from patients with COVID-19 and healthy controls to identify distinguishing metabolic biosignatures. Univariate and multivariate analyses were applied to obtain diagnostic and prognostic metabolic phenotypes. Results: Significant changes in metabolic profiles distinguished stage 1 sarcoidosis from healthy controls, with potential biomarkers including azelaic acid, itaconate, and glutarate. Distinct metabolic phenotypes were observed across the stages of sarcoidosis, with stage 2 exhibiting greater heterogeneity compared with stages 1, 3, and 4. Conclusions: we explored immunometabolic phenotypes by comparing patients with sarcoidosis with patients with COVID-19 and healthy controls, revealing potential metabolic pathways associated with acute and chronic inflammation across the stages of sarcoidosis. Full article