Metropolitan pressures: Significant biodiversity declines and strong filtering of functional traits in fish assemblages.

Accelerating global urbanization is leading to drastic losses and restructuring of biodiversity. Although it is crucial to understand urban impacts on biodiversity to develop mitigation strategies, there is a dearth of knowledge on the functional structure of fish assemblages spanning the entire city-scale spectrum of urbanization intensity. Here, using environmental DNA sampled from 109 water sites in Beijing, we investigated the taxonomic and functional diversity patterns of fish assemblages across the city and uncovered community-, trait-, and species-level responses to various environmental stressors. By ranking sampling sites into three disturbance levels according to water physiochemical and landcover conditions, we found that both native and non-native fish taxonomic and functional α-diversity decreased significantly with elevating disturbance, as strong disturbance led to the disappearance of many species. However, the quantitative taxonomic and functional ß-diversity components of native and non-native fish showed distinct patterns; assemblage turnover dominated native fish ß-diversity and decreased with increasing disturbance, whereas species/trait richness differences dominated non-native fish ß-diversity and increased with disturbance intensity particularly in lotic waters. RLQ and fourth-corner analyses revealed that fish size, fecundity, diet, and reproductive behaviors were significantly correlated with water quality, with pollution-tolerant, larger-sized native and omnivorous non-native fishes being urban winners, which indicates strong trait-dependent environmental filtering. Potential ecological indicator species were identified based on the sensitivity of fish responses to pollution loads; these were mostly small native species, and many have bivalve-dependent reproduction. Our results demonstrate that, along with native fish assemblage simplification and homogenization, urban stressors exert profound impacts on community trait composition, highlighting the need to consider both biodiversity loss and functional reorganization in combating disturbance of aquatic ecosystems under global urbanization. Furthermore, correlations between cropland cover and water nutrient level suggested that the management of agricultural runoff might be critically important for safeguarding urban water quality.

In Vitro Titan Cell Generation in Cryptococcus neoformans and Automated Cell Size Measurements.

A special feature of the human fungal pathogen Cryptococcus neoformans is its morphological changes triggered by the interaction with the host. During infection, a specific increase in cell size is observed, particularly in lung tissue, from a typical cell size of 5-7 µm cells to cells larger than 10 µm, dubbed titan cells (TCs). However, the study of this specific cell subpopulation was, until now, only possible via recovery of TCs from lungs of mice during experimental infections where stable and reproducible generation of TCs occurs.The protocol described here generates TCs using in vitro conditions and measures cell size using a rapid, automated method. TC generation in vitro is robust and reproducible, generating yeast cells harboring the same characteristics of TCs generated in vivo.

Human plasma-like medium (HPLM) induces Cryptococcus neoformans in vivo cell morphologies.

The fungal pathogen Cryptococcus neoformans (C. neoformans) forms yeast cells of different sizes and morphological characteristics during infection. These features are usually not seen in standard laboratory in vitro conditions. Here, we describe in vivo cell morphologies when C. neoformans is grown in human plasma-like medium at 37°C, 5% CO2. We observed mixed-size populations of cells less than 1 µm up to 16.8 µm in cell diameter, increased capsule size, high chitin, and DNA content in larger cells. Our findings show that serum is not required for human plasma-like medium (HPLM)-induced C. neoformans cellular heterogeneity. Thus, this new method offers an opportunity to investigate factors of C. neoformans that mediate pathogenesis or host-pathogen interactions in a physiologically relevant setting.IMPORTANCEWe provide a description of new in vitro culture condition using the human plasma-like medium that supports the formation of the full range of in vivo cell morphologies of C. neoformans.

Interaction of selected alkoxy naringenin oximes with model and bacterial membranes.

Naringenin is a flavonoid found in many fruits and herbs, most notably in grapefruits. In recent years, this compound and its derivatives have been of great interest due to their high biological activity, including fungicidal and bactericidal effects, also in relation to multidrug-resistant bacteria. Membrane interactions of naringenin oxime (NO) and its 7-O-alkyl (7-alkoxy) derivatives, such as methyl (7MENO), ethyl (7ETNO), isopropyl (7IPNO), n-butyl (7BUNO) and n-pentyl (7PENO) were studied. Thermotropic properties of model membranes were investigated via differential scanning calorimetry (DSC), the influence on lipid raft mimicking giant unilamellar vesicles (GUVs) via fluorescence microscopy, and membrane permeability via measuring calcein leakage from liposomes. Molecular calculations supplemented the study. The influence of naringenin oximes on two strains of multidrug resistant bacteria: Staphylococcus aureus KJ and Enterococcus faecalis 37VRE was also investigated. In DSC studies all compounds reduced the temperature and enthalpy of main phase transition and caused disappearing of the pretransition. NO was the least active. The reduction in the area of surface domains in GUVs was observed for NO. Compounds NO and 7BUNO resulted in very low secretion of calcein from liposomes (permeability < 3 %). The highest results were observed for 7MENO (88.4 %) and 7IPNO (78.5 %). When bacterial membrane permeability was investigated all compounds caused significant release of propidium iodide from S. aureus (31.6-87.0 % for concentration 128 µg/mL). In the case of E. faecalis, 7ETNO (75.7 %) and NO (28.8 %) were the most active. The rest of the tested compounds showed less activity (permeability < 13.9 %). The strong evidence was observed that antibacterial activity of the tested compounds may be associated with their interaction with bacterial membrane.

Dimethylformamide dimethyl acetal reagent for in situ chiral analyses of organic molecules on Titan with the Dragonfly mass spectrometer space instrument (Dragonfly mission).

Thanks to the Cassini-Huygens space mission between 2004 and 2017, a lot was learned about Titan, the biggest satellite of Saturn, and its intriguing atmosphere, surface, and organic chemistry complexity. However, key questions about the potential for the atmosphere and surface chemistry to produce organic molecules of direct interest for prebiotic chemistry and life did not find an answer. Due to Titan potential as a habitable world, NASA selected the Dragonfly space mission to be launched in 2027 to Titan's surface and explore the Shangri-La surface region for minimum 3 years. One of the main goals of this mission will be to understand the past and actual abundant prebiotic chemistry on Titan, especially using the Dragonfly Mass Spectrometer (DraMS). Two recently used sample pre-treatments for Gas Chromatography - Mass Spectrometry (GC-MS mode of DraMS) analyses are planned prior analysis to extract refractory organic molecules of interest for prebiotic chemistry and astrobiology. The dimethylformamide dimethylacetal (DMF-DMA) derivatization reaction offers undoubtedly an opportunity to detect biosignatures by volatilizing refractory biological or prebiotic molecules and conserving the chiral carbons' conformation while an enantiomeric excess indicates a chemical feature induced primarily by life (and may be aided on the primitive systems by light polarization). The goal of this study is to investigate the ageing of DMF-DMA in DraMS (and likely MOMA) capsules prior to in situ analysis on Titan (or Mars). The main results highlighted by our work on DMF-DMA are first its satisfactory stability for space requirements through time (no significant degradation over a year of storage and less than 30 % of lost under thermal stress) to a wide range of temperature (0 °C to 250 °C), or the presence of water and oxidants during the derivatization reaction (between 0 and 10 % of DMF-DMA degradation). Moreover, this reagent derivatized very well amines and carboxylic acids in high or trace amounts (ppt to hundreds of ppm), conserving their molecular conformation during the heat at 145 °C for 3 min (0 to 4% in the enantiomeric form change).

[Surgical treatment of extensive metastatic tumor of the left ribs III-V and lung in 13 years after resection of cylindroma of the soft palate]. / Khirurgicheskoe lechenie obshirnoi metastaticheskoi opukholi III­V reber i legkogo sleva spustya 13 let posle udaleniya tsilindromy myagkogo neba.

Metastatic chest lesion is rare in patients with soft palate tumors. We present a 52-year-old patient with metastatic lesion of the left ribs III-V and lung in 13 years after resection of cylindroma of the soft palate. The patient underwent successful chest reconstruction and atypical resection of the left lung. Isolation of the pleural cavity by xenopericardial patches and preoperative 3D CT modeled titanium implants meet all the requirements for maintaining the chest function. This approach also positively affects postoperative period and recovery. The above-described method of replacing chest defects is highly effective.

Organic Input to Titan's Subsurface Ocean Through Impact Cratering.

Titan has an organic-rich atmosphere and surface with a subsurface liquid water ocean that may represent a habitable environment. In this work, we determined the amount of organic material that can be delivered from Titan's surface to its ocean through impact cratering. We assumed that Titan's craters produce impact melt deposits composed of liquid water that can founder in its lower-density ice crust and estimated the amount of organic molecules that could be incorporated into these melt lenses. We used known yields for HCN and Titan haze hydrolysis to determine the amount of glycine produced in the melt lenses and found a range of possible flux rates of glycine from the surface to the subsurface ocean. These ranged from 0 to 1011 mol/Gyr for HCN hydrolysis and from 0 to 1014 mol/Gyr for haze hydrolysis. These fluxes suggest an upper limit for biomass productivity of ∼103 kgC/year from a glycine fermentation metabolism. This upper limit is significantly less than recent estimates of the hypothetical biomass production supported by Enceladus's subsurface ocean. Unless biologically available compounds can be sourced from Titan's interior, or be delivered from the surface by other mechanisms, our calculations suggest that even the most organic-rich ocean world in the Solar System may not be able to support a large biosphere.

Biological functions at high pressure: transcriptome response of Shewanella oneidensis MR-1 to hydrostatic pressure relevant to Titan and other icy ocean worlds.

High hydrostatic pressure (HHP) is a key driver of life's evolution and diversification on Earth. Icy moons such as Titan, Europa, and Enceladus harbor potentially habitable high-pressure environments within their subsurface oceans. Titan, in particular, is modeled to have subsurface ocean pressures ≥ 150 MPa, which are above the highest pressures known to support life on Earth in natural ecosystems. Piezophiles are organisms that grow optimally at pressures higher than atmospheric (0.1 MPa) pressure and have specialized adaptations to the physical constraints of high-pressure environments - up to ~110 MPa at Challenger Deep, the highest pressure deep-sea habitat explored. While non-piezophilic microorganisms have been shown to survive short exposures at Titan relevant pressures, the mechanisms of their survival under such conditions remain largely unelucidated. To better understand these mechanisms, we have conducted a study of gene expression for Shewanella oneidensis MR-1 using a high-pressure experimental culturing system. MR-1 was subjected to short-term (15 min) and long-term (2 h) HHP of 158 MPa, a value consistent with pressures expected near the top of Titan's subsurface ocean. We show that MR-1 is metabolically active in situ at HHP and is capable of viable growth following 2 h exposure to 158 MPa, with minimal pressure training beforehand. We further find that MR-1 regulates 264 genes in response to short-term HHP, the majority of which are upregulated. Adaptations include upregulation of the genes argA, argB, argC, and argF involved in arginine biosynthesis and regulation of genes involved in membrane reconfiguration. MR-1 also utilizes stress response adaptations common to other environmental extremes such as genes encoding for the cold-shock protein CspG and antioxidant defense related genes. This study suggests Titan's ocean pressures may not limit life, as microorganisms could employ adaptations akin to those demonstrated by terrestrial organisms.

Reactivity of the Ethenium Cation (C2H5+) with Ethyne (C2H2): A Combined Experimental and Theoretical Study.

The gas-phase reaction between the ethyl cation (C2H5+) and ethyne (C2H2) is re-investigated by measuring absolute reactive cross sections (CSs) and branching ratios (BRs) as a function of collision energy, in the thermal and hyperthermal energy range, via tandem-guided ion beam mass spectrometry under single collision conditions. Dissociative photoionization of C2H5Br using tuneable VUV radiation in the range 10.5-14.0 eV is employed to generate C2H5+, which has also allowed us to explore the impact of increasing (vibrational) excitation on the reactivity. Reactivity experiments are complemented by theoretical calculations, at the G4 level of theory, of the relative energies and structures of the most relevant stationary points on the reactive potential energy hypersurface (PES) and by mass-analyzed ion kinetic energy (MIKE) spectrometry experiments to probe the metastable decomposition from the [C4H7]+ PES and elucidate the underlying reaction mechanisms. Two main product channels have been identified at a centre-of-mass collision energy of ∼0.1 eV: (a) C3H3++CH4, with BR = 0.76±0.05 and (b) C4H5++H2, with BR = 0.22±0.02. A third channel giving C2H3+ in association with C2H4 is shown to emerge at both high internal excitation of C2H5+ and high collision energies. From CS measurements, energy-dependent total rate constants in the range 4.3×10-11-5.2×10-10 cm3·molecule-1·s-1 have been obtained. Theoretical calculations indicate that both channels stem from a common covalently bound intermediate, CH3CH2CHCH+, from which barrierless and exothermic pathways exist for the production of both cyclic c-C3H3+ and linear H2CCCH+ isomers of the main product channel. For the minor C4H5+ product, two isomers are energetically accessible: the three-member cyclic isomer c-C3H2(CH3)+ and the higher energy linear structure CH2CHCCH2+, but their formation requires multiple isomerization steps and passages via transition states lying only 0.11 eV below the reagents' energy, thus explaining the smaller BR. Results have implications for the modeling of hydrocarbon chemistry in the interstellar medium and the atmospheres of planets and satellites as well as in laboratory plasmas (e.g., plasma-enhanced chemical vapor deposition of carbon nanotubes and diamond-like carbon films).

Molecular assembly indices of mineral heteropolyanions: some abiotic molecules are as complex as large biomolecules.

Molecular assembly indices, which measure the number of unique sequential steps theoretically required to construct a three-dimensional molecule from its constituent atomic bonds, have been proposed as potential biosignatures. A central hypothesis of assembly theory is that any molecule with an assembly index ≥15 found in significant local concentrations represents an unambiguous sign of life. We show that abiotic molecule-like heteropolyanions, which assemble in aqueous solution as precursors to some mineral crystals, range in molecular assembly indices from 2 for H2CO3 or Si(OH)4 groups to as large as 21 for the most complex known molecule-like subunits in the rare minerals ewingite and ilmajokite. Therefore, values of molecular assembly indices ≥15 do not represent unambiguous biosignatures.

Accumulation of endogenous free radicals is required to induce titan-like cell formation in Cryptococcus neoformans.

IMPORTANCE: Cryptococcus neoformans is an excellent model to investigate fungal pathogenesis. This yeast can produce "titan cells," which are cells of an abnormally larger size that contribute to the persistence of the yeast in the host. In this work, we have used a new approach to characterize them by identifying drugs that inhibit this process. We have used a repurposing off-patent drug library, combined with an automatic method to image and analyze fungal cell size. In this way, we have identified many compounds that inhibit this transition. Interestingly, several compounds were antioxidants, allowing us to confirm that endogenous ROS and mitochondrial changes are important for titan cell formation. This work provides new evidence of the mechanisms required for titanization. Furthermore, the future characterization of the inhibitory mechanisms of the identified compounds by the scientific community will contribute to better understand the role of titan cells in virulence.

Femoral revision in total hip arthroplasty using a cementless modular stem: clinical and radiological results with a 8-year follow-up.

INTRODUCTION: Modular femoral components allow for patient-specific restoration of hip joint geometry and the reconstruction of extensive bone defects in revision total hip arthroplasty (THA); however, potential problems of modular implants such as taper corrosion and the risk of implant fracture continue to be of concern. The aim of the present study was to evaluate the clinical and radiological results of a cementless modular revision stem following revision surgery due to aseptic loosening and periprosthetic fracture and to assess patient-reported outcome measures (PROMs) in these patients at mid-term follow-up. MATERIALS AND METHODS: In this study, a consecutive cohort of 75 patients who underwent primary revision THA at our institution using a modular cementless stem design (MRP-TITAN stem) was retrospectively evaluated at a mean follow-up of 7.7 years. Kaplan-Meier survivorship analyses were performed with revision of the femoral component for any reason as the end point. The Harris-Hip Score, the UCLA Activity Score, the Forgotten Joint Score and the SF-12 Score were used for clinical assessment. We used the Wilcoxon signed rank test to compare pre- and postoperative clinical scores. RESULTS: Overall stem survival with the endpoint stem re-revision for any reason was 85.4% at a mean follow-up of 7.7 years (range 2.4-14 years). Stem survival was 89.5% in the aseptic loosening group and 78.3% in the periprosthetic fracture group with no statistically significant difference between both groups (p = 0.107). One patient had to be revised due to taper fracture. PROMs improved significantly up to the latest follow-up, and radiographic evaluation showed full osseointegration of all stems in this cohort. CONCLUSIONS: Revision THA using a modular cementless titanium revision stem demonstrated adequate clinical and radiological results at mid- to long-term follow-up in this cohort. Cementless revision stems are a useful treatment option to restore the anatomy, especially in deformed hips and in complex revision hip arthroplasty. However, there are some significant disadvantages related to an increased risk of mechanical failure such as corrosion/fretting damage and implant fracture. Future high-quality prospective studies with longer follow-up are necessary to confirm the supposed advantages.

On the roles of function and selection in evolving systems.

Physical laws-such as the laws of motion, gravity, electromagnetism, and thermodynamics-codify the general behavior of varied macroscopic natural systems across space and time. We propose that an additional, hitherto-unarticulated law is required to characterize familiar macroscopic phenomena of our complex, evolving universe. An important feature of the classical laws of physics is the conceptual equivalence of specific characteristics shared by an extensive, seemingly diverse body of natural phenomena. Identifying potential equivalencies among disparate phenomena-for example, falling apples and orbiting moons or hot objects and compressed springs-has been instrumental in advancing the scientific understanding of our world through the articulation of laws of nature. A pervasive wonder of the natural world is the evolution of varied systems, including stars, minerals, atmospheres, and life. These evolving systems appear to be conceptually equivalent in that they display three notable attributes: 1) They form from numerous components that have the potential to adopt combinatorially vast numbers of different configurations; 2) processes exist that generate numerous different configurations; and 3) configurations are preferentially selected based on function. We identify universal concepts of selection-static persistence, dynamic persistence, and novelty generation-that underpin function and drive systems to evolve through the exchange of information between the environment and the system. Accordingly, we propose a "law of increasing functional information": The functional information of a system will increase (i.e., the system will evolve) if many different configurations of the system undergo selection for one or more functions.

Protecting the invisible: Establishing guideline values for copper toxicity to marine microbiomes.

Understanding the rapid responses of marine microbiomes to environmental disturbances is paramount for supporting early assessments of harm to high-value ecosystems, such as coral reefs. Yet, management guidelines aimed at protecting aquatic life from environmental pollution remain exclusively defined for organisms at higher trophic levels. In this study, 16S rRNA gene amplicon sequencing was applied in conjunction with propidium monoazide for cell-viability assessment as a sensitive tool to determine taxon- and community-level changes in a seawater microbial community under copper (Cu) exposure. Bayesian model averaging was used to establish concentration-response relationships to evaluate the effects of copper on microbial composition, diversity, and richness for the purpose of estimating microbiome Hazard Concentration (mHCx) values. Predicted mHC5 values at which a 5 % change in microbial composition, diversity, and richness occurred were 1.05, 0.72, and 0.38 µg Cu L-1, respectively. Threshold indicator taxa analysis was applied across the copper concentrations to identify taxon-specific change points for decreasing taxa. These change points were then used to generate a Prokaryotic Sensitivity Distribution (PSD), from which mHCxdec values were derived for copper, suitable for the protection of 99, 95, 90, and 80 % of the marine microbiome. The mHC5dec guideline value of 0.61 µg Cu L-1, protective of 95 % of the marine microbial community, was lower than the equivalent Australian water quality guideline value based on eukaryotic organisms at higher trophic levels. This suggests that marine microbial communities might be more vulnerable, highlighting potential insufficiencies in their protection against copper pollution. The mHCx values proposed here provide approaches to quantitatively assess the effects of contaminants on microbial communities towards the inclusion of prokaryotes in future water quality guidelines.

Reconstructing river flows remotely on Earth, Titan, and Mars.

Alluvial rivers are conveyor belts of fluid and sediment that provide a record of upstream climate and erosion on Earth, Titan, and Mars. However, many of Earth's rivers remain unsurveyed, Titan's rivers are not well resolved by current spacecraft data, and Mars' rivers are no longer active, hindering reconstructions of planetary surface conditions. To overcome these problems, we use dimensionless hydraulic geometry relations-scaling laws that relate river channel dimensions to flow and sediment transport rates-to calculate in-channel conditions using only remote sensing measurements of channel width and slope. On Earth, this offers a way to predict flow and sediment flux in rivers that lack field measurements and shows that the distinct dynamics of bedload-dominated, suspended load-dominated, and bedrock rivers give rise to distinct channel characteristics. On Mars, this approach not only predicts grain sizes at Gale Crater and Jezero Crater that overlap with those measured by the Curiosity and Perseverance rovers, it enables reconstructions of past flow conditions that are consistent with proposed long-lived hydrologic activity at both craters. On Titan, our predicted sediment fluxes to the coast of Ontario Lacus could build the lake's river delta in as little as ~1,000 y, and our scaling relationships suggest that Titan's rivers may be wider, slope more gently, and transport sediment at lower flows than rivers on Earth or Mars. Our approach provides a template for predicting channel properties remotely for alluvial rivers across Earth, along with interpreting spacecraft observations of rivers on Titan and Mars.

Assessment the impact of different fuels used in cement industry on pollutant emissions and ambient air quality: a case study in Egypt.

This study aims to assess the impact of using different fuels in Egyptian Titan Alexandria Portland Cement Company on emissions and concentrations of pollutants (Total suspended particles (TSP), nitrogen dioxide (NO2 ), and sulfur dioxide (SO2)) and their influence on ambient air quality during the period 2014-2020 using AERMOD dispersion model. The results showed that changing the fuel from natural gas in 2014 to coal mixed with alternative fuels (Tire-Derived Fuel (TDF), Dried Sewage Sludge (DSS), and Refuse Derived Fuels (RDF)) in 2015-2020 caused fluctuating variations in pollutant emissions and concentrations. The highest and lowest maximum concentrations of TSP occurred in 2017 and 2014 respectively, where the TSP is positively correlated with coal, RDF, and DSS and negatively correlated with natural gas, diesel, and TDF. Also, the lowest and highest maximum NO2 concentrations were detected in 2020 and 2016 followed by 2017 respectively, where NO2 is positively correlated with DSS and negatively correlated with TDF and varies with diesel, coal, and RDF. Moreover, the maximum concentrations of SO2 were the lowest in 2018 and highest in 2016 followed by 2017 because of its considerable positive correlation with natural gas and DSS and negative correlation with RDF, TDF, and coal. Generally, it was found that increasing the percentage of TDF and RDF with decreasing the percentage of DSS, diesel, and coal will reduce pollutant emissions and concentrations and enhance ambient air quality.

C1q Confers Protection Against Cryptococcal Lung Infection by Alleviating Inflammation and Reducing Cryptococcal Virulence.

Background: To define the role of C1qa in host defense against Cryptococcus neoformans lung infection, we investigated its susceptibility to cryptococcal lung infection in mice deficient in complement factor C1qa (C1qa-/- ). Methods: We established a wild-type (WT) and C1qa-deficient murine inhalation model with C. neoformans. We compared the host survival rate, inflammatory responses, and pathogenicity of C. neoformans during the infection course between WT and C1qa-/- mice. Results: The mortality rate of C1qa-deficient mice was significantly higher than that of wild-type mice. The increased formation of Titan cells in the lungs was associated with augmented inflammation in C1qa-deficient mice. The capacity of lung homogenate supernatant from C1qa-deficient mice to induce Titan formation in vitro was greater compared with that of wild-type mice. The C. neoformans isolated from the lungs of infected C1qa-deficient mice was more resistant to macrophage killing in vitro and caused significantly higher mortality after administration to mice compared with that isolated from WT mice. Conclusions: These findings reveal a novel role of C1qa in host defense against C. neoformans infection by regulating host inflammation and pathogen virulence and provide new insight into the C1q-mediated lung environment underlying the transition from yeast to Titan cell.

Organoselenium Has a Potent Fungicidal Effect on Cryptococcus neoformans and Inhibits the Virulence Factors.

Cryptococcosis therapy is often limited by toxicity problems, antifungal tolerance, and high costs. Studies approaching chalcogen compounds, especially those containing selenium, have shown promising antifungal activity against pathogenic species. This work aimed to evaluate the in vitro and in vivo antifungal potential of organoselenium compounds against Cryptococcus neoformans. The lead compound LQA_78 had an inhibitory effect on C. neoformans planktonic cells and dispersed cells from mature biofilms at similar concentrations. The fungal growth inhibition led to an increase in budding cells arrested in the G2/M phase, but the compound did not significantly affect structural cell wall components or chitinase activity, an enzyme that regulates the dynamics of the cell wall. The compound also inhibited titan cell (Tc) and enlarged capsule yeast (NcC) growth and reduced the body diameter and capsule thickness associated with increased capsular permeability of both virulent morphotypes. LQA_78 also reduced fungal melanization through laccase activity inhibition. The fungicidal activity was observed at higher concentrations (16 to 64 µg/mL) and may be associated with augmented plasma membrane permeability, ROS production, and loss of mitochondrial membrane potential. While LQA_78 is a nonhemolytic compound, its cytotoxic effects were cell type dependent, exhibiting no toxicity on Galleria mellonella larvae at a dose ≤46.5 mg/kg. LQA_78 treatment of larvae infected with C. neoformans effectively reduced the fungal burden and inhibited virulent morphotype formation. To conclude, LQA_78 displays fungicidal action and inhibits virulence factors of C. neoformans. Our results highlight the potential use of LQA_78 as a lead molecule for developing novel pharmaceuticals for treating cryptococcosis.

Selection and Analytical Performances of the Dragonfly Mass Spectrometer Gas Chromatographic Columns to Support the Search for Organic Molecules of Astrobiological Interest on Titan.

Titan is a key planetary body for astrobiology, with the presence of a subsurface ocean and a dense atmosphere, in which complex chemistry is known to occur. Approximately 1-Titan-year after the Cassini-Huygens mission arrived in the saturnian system, Dragonfly rotorcraft will land on Titan's surface by 2034 for an exhaustive geophysical and chemical investigation of the Shangri-La organic sand sea region. Among the four instruments onboard Dragonfly, the Dragonfly Mass Spectrometer (DraMS) is dedicated to analyze the chemical composition of surface samples and noble gases in the atmosphere. One of the DraMS analysis modes, the Gas Chromatograph-Mass Spectrometer (GC-MS), is devoted to the detection and identification of organic molecules that could be involved in the development of a prebiotic chemistry or even representative of traces of past or present life. Therefore, DraMS-GC subsystem should be optimized to detect and identify relevant organic compounds to meet this objective. This work is focused on the experimental methods employed to select the chromatographic column to be integrated in DraMS-GC, to assess the analytical performances of the column selected, and also to assess the performances of the second DraMS-GC column, which is devoted to the separation of organic enantiomers. Four different stationary phases have been tested to select the most relevant one for the separation of the targeted chemical species. The results show that the stationary phase composed of polymethyl (95%) diphenyl (5%) siloxane is the best compromise in terms of efficiency, robustness, and retention times of the molecules. The combination of the general and the chiral columns in DraMS is perfectly suited to in situ chemical analysis on Titan and for the detection of expected diverse and complex organic compounds.

Development and verification of chemical chromogenic method for determination of residual cetyltrimethyl ammonium bromide content in ACYW135 meningococcal polysaccharide stock solution / 中国生物制品学杂志

@#Objective To develop and verify a chemical choromogenic method for the determination of residual cetyltrimethylammonium bromide(CTAB)content in ACYW135 meningococcal polysaccharide stock solution. Methods A chemical chromogenic method was developed for the determination of residual CTAB content by using titan yellow as chromogenic reagent,and verified for the linear range,intermediate precision and accuracy. ACYW135 meningococcal polysaccharide stock solution were determined for residual CTAB content by the developed method. Results The CTAB reference at concentrations of 4. 0～10. 0 μg/mL showed good linear relationship to A_(500),with a R~2 value of more than 0. 990. The recovery rates of CTAB standard at concentrations of 5. 0,7. 0,and 9. 0 μg/mL were all within 95% ～ 110% in six repeated tests,with the CV values of determination results of less than 10%. All the residual CTAB contents in four batches of meningococcal polysaccharide stock solutions were less than 8. 0 μg/mL. Conclusion The chemical chromogenic method showed good linearity,intermediate precision and accuracy,which might be used for the determination of residual CTAB content in ACYW135 meningococcal polysaccharide stock solution.