Independent Experiments Research Articles

Dragonfly larvae rearing: experimental insights and best practices.

Understanding and optimizing rearing conditions for dragonfly larvae is crucial for ecological research and conservation efforts, yet optimal rearing conditions and general rearing practices are lacking. In this study, we investigated the effect of temperature, amount of oxygen in water, presence of (artificial) plants, and age of eggs on hatchability, survival, and development of dragonfly larvae using the model species Sympetrum striolatum. We conducted three independent experiments and assessed variability between egg clutches of individual females, as well as the occurrence of cannibalism among larvae. Our results showed that egg hatchability varied significantly between individual females and was negatively affected by egg aging and the presence of artificial plants. Larval survival was negatively affected by water temperatures above 24°C, the presence of artificial plants, and egg aging, and positively affected by high feeding frequency, in certain instars. Notably, cannibalism was observed among later instar larvae, especially under higher density conditions. Based on these findings, we provide practical recommendations for optimizing dragonfly larvae rearing protocols, emphasizing the importance of maintaining optimal temperature, appropriate feeding regimes, and managing larval density to reduce cannibalism. This study offers experimental, evidence-based guidelines for dragonfly larvae rearing, contributing to improved research methodologies and conservation efforts.

Ligand interaction landscape of transcription factors and essential enzymes in E.coli.

Knowledge of protein-metabolite interactions can enhance mechanistic understanding and chemical probing of biochemical processes, but the discovery of endogenous ligands remains challenging. Here, we combined rapid affinity purification with precision mass spectrometry and high-resolution molecular docking to precisely map the physical associations of 296 chemically diverse small-molecule metabolite ligands with 69 distinct essential enzymes and 45 transcription factors in the gram-negative bacterium Escherichia coli. We then conducted systematic metabolic pathway integration, pan-microbial evolutionary projections, and independent in-depth biophysical characterization experiments to define the functional significance of ligand interfaces. This effort revealed principles governing functional crosstalk on a network level, divergent patterns of binding pocket conservation, and scaffolds for designing selective chemical probes. This structurally resolved ligand interactome mapping pipeline can be scaled to illuminate the native small-molecule networks of complete cells and potentially entire multi-cellular communities.

Mechanisms of the Photomechanical Response in Thin-Film Dye-Doped Glassy Polymers.

This work aims to determine the mechanism of the photomechanical response of poly(Methyl methacrylate) polymer doped with the photo-isomerizable dye Disperse Red 1 using the non-isomerizable dye Disperse Orange 11 as a control to isolate photoisomerization. Samples are free-standing thin films with thickness that is small compared with the optical skin depth to assure uniform illumination and photomechanical response throughout their volume, which differentiates these studies from most others. Polarization-dependent measurements of the photomechanical stress response are used to deconvolute the contributions of angular hole burning, molecular reorientation and photothermal heating. While photo-isomerization of dopant molecules is commonly observed in dye-doped polymers, the shape changes of a molecule might not couple strongly to the host polymer through steric mechanical interactions, thus not contributing substantially to a macroscopic shape change. To gain insights into the effectiveness of such mechanical coupling, we directly probe the dopant molecules using dichroism measurements simultaneously while measuring the photomechanical response and find mechanical coupling to be small enough to make photothermal heating-mediated by the transfer of optical energy as heat to the polymer-the dominant mechanism. We also predict the fraction of light energy converted to mechanical energy using a model whose parameters are thermodynamic material properties that are measured with independent experiments. We find that in the thin-film geometry, these dye-doped glassy polymers are as efficient as any other material but their large Young's modulus relative to other organic materials, such as liquid crystal elastomers, makes them suitable in applications that require mechanically strong materials. The mechanical properties and the photomechanical response of thin films are observed to be significantly different than in fibers, suggesting that the geometry of the material and surface effects might play an important role.

Is the time to task failure during severe intensity exercise associated with muscle, blood, and respiratory changes?

Purpose: The study aimed to verify the physiological and metabolic parameters associated with the time to task failure (TTF) during cycling exercise performed within the severe-intensity domain. Methods: Forty-five healthy and physically active males participated in two independent experiments. In experiment 1, after a graded exercise test, participants underwent constant work rate cycling efforts (CWR) at 115% of peak power output to assess neuromuscular function (Potentiated twitch) pre- and post-exercise. Experiment 2 was similarl to experiment 1, but with physiological (respiratory parameters, energetic pathway contribution) and metabolic parameters in the blood (gasometry and blood lactate responses) and vastus lateralis muscle tissue (target metabolomic analysis, glycogen content, muscle pH and buffering capacity in vitro) measured instead of neuromuscular function. Results: Experiment 1 evidenced a significant decrease in muscle force with instauration of peripheral fatigability indices and no change in central fatigue indices. Severe-intensity domain exercise in Experiment 2 was accompanied by changes in physiological and metabolic parameters and in blood and muscle parameters. However, the TTF was associated with oxidative contribution (r=0.811, p<0.001), as well as anaerobic capacity (r=0.554, p=0.027), muscle buffering capacity (r=0.792, p=0.035), phosphagen energy contribution (r=0.583, p=0.017), and carnitine changes (r=0.855, p=0.016), but no correlated with electromyographic response, blood acid-base balance, and muscular glycogen content and pH. Conclusion: TTF during CWR exercise within the severe-intensity domain is likely explained by a combination of interacting mechanisms, with oxidative and phosphagen contributions, and muscle buffering capacity suggested as the main peripherals limiting factors to exercise within this exercise intensity domain.

Stress Granule Induction in Rat Retinas Damaged by Constant LED Light.

Stress granules (SGs) are cytoplasmic biocondensates formed in response to various cellular stressors, contributing to cell survival. Although implicated in diverse pathologies, their role in retinal degeneration (RD) remains unclear. We aimed to investigate SG formation in the retina and its induction by excessive LED light in an RD model. Rat retinas were immunohistochemically analyzed for SG markers G3BP1 and eIF3, and SGs were also visualized by RNA fluorescence in situ hybridization. Additionally, SGs were induced in primary retinal cell and eyeball cultures using sodium arsenite. Light exposure experiments used LED lamps with a color temperature of 5500 K and 200 lux intensity for short-term or two- to eight-day exposures. SGs were predominantly detected in retinal ganglion cells (RGCs) and inner nuclear layer (INL) cells, with arsenite-induction verified in RGCs. SG abundance was higher in animals exposed to light for 2-8 days compared to light/dark cycle controls. RGCs consistently exhibited more SGs than INL cells, and INL cells more than outer nuclear layer (ONL) cells (Scheirer-Ray-Hare test: H = 13.2, P = 0.0103 for light condition, and H = 278.2, P < 0.00001 for retinal layer). These observations were consistent across four independent experiments, each with three animals per light condition. This study characterizes SGs in the mammalian retina for the first time, with increased prevalence after excessive LED light exposure. RGCs and INL cells showed heightened SG formation, suggesting a potential protective mechanism against photodamage. Further investigations are warranted to elucidate the role of SGs in shielding against light stress and their implications in retinopathies.

Time-resolved effects of short-term overfeeding on energy balance in mice.

To curb the obesity epidemic, it is imperative that we improve our understanding of the mechanisms controlling fat mass and body weight regulation. While great progress has been made in mapping the biological feedback forces opposing weight loss, the mechanisms countering weight gain remain less well defined. Here, we integrate a mouse model of intragastric overfeeding with a comprehensive evaluation of the regulatory aspects of energy balance, encompassing food intake, energy expenditure, and fecal energy excretion. Furthermore, to assess the role of adipose tissue thermogenesis in protecting against overfeeding-induced weight gain, we analyze the expression of genes involved in futile metabolic cycles in response to overfeeding and subject uncoupling protein 1 (UCP1) knockout (KO) mice to intragastric overfeeding. Data from two independent experiments demonstrate that 7 days of 140-150% overfeeding results in substantial weight gain and triggers a potent, sustained decrease in voluntary food intake, which coincides with a gradual return of body weight toward baseline after overfeeding. Intragastric overfeeding triggers an increase in energy expenditure that seems to be adaptive. However, mice lacking UCP1 are not impaired in their ability to defend against overfeeding-induced weight gain. Finally, we show that fecal energy excretion decreases in response to overfeeding, but only during the recovery period, driven primarily by a reduction in fecal output rather than in fecal caloric density. In conclusion, while overfeeding may induce adaptive thermogenesis, the primary protective response to forced weight gain in mice appears to be a potent reduction in food intake.

An electrochemical sensor based on electrodeposited methylene blue on a carbon nanotube decorated hydrogel for the detection of ascorbic acid.

In this study, a self-assembled electrochemical sensor was prepared by coating with a carbon nanotube (CNT) decorated hydrogel (HG) combined with electrodeposition of methylene blue (MB), and then used for the detection of ascorbic acid (AA). The three-dimensional network of HG has the advantages of large electroactive surface area, rapid diffusion and electron transfer rate, strong adhesive ability and stabilization of the polymerized MB. The MB provides high electrocatalytic activity and works as an electron transfer mediator to facilitate the oxidation of AA. The successful synthesis of the hydrogel and the preparation of the sensor are confirmed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The layer-by-layer assembly was identified by AFM with the heights of 22.1 nm and 186.8 nm for the hydrogel and MB layers, respectively. Under the optimal conditions, the sensor has a linear range of 0.1 mM to 10 mM and a detection limit of 0.05 mM. What's more, the prepared sensor also exhibits good stability (current retention of 91.22% after 100 cycles for testing 0.25 mM AA), excellent anti-interference ability, good reproducibility (RSD of 4.26% for five independent experiments), excellent operational stability (RSD of 1.66% for 30 consecutive AA additions), fast response time (<4 s) and shows satisfactory results in the detection of AA in vitamin C tablets.

Influence of the glycocalyx on the size and mechanical properties of plasma membrane-derived vesicles.

Recent studies have reported that the overexpression of MUC1 glycoproteins on cell surfaces changes the morphology of cell plasma membranes and increases the blebbing of vesicles from them, supporting the hypothesis that entropic forces exerted by MUC1 change the spontaneous curvature of cell membranes. However, how MUC1 is incorporated into and influences the size and biophysical properties of plasma-membrane-blebbed vesicles is not understood. Here we report single-vesicle-level characterization of giant plasma membrane vesicles (GPMVs) derived from cells overexpressing MUC1, revealing a 40× variation in MUC1 density between GPMVs from a single preparation and a strong correlation between GPMV size and MUC1 density. By dispersing GPMVs in aqueous liquid crystals (LCs), we show that the elasticity of the LC can be used to strain individual GPMVs into spindle-like shapes, consistent with the straining of fluid-like membranes. To quantify the influence of MUC1 on membrane mechanical properties, we analyze the shapes of strained GPMVs within a theoretical framework that integrates the effects of MUC1 density and GPMV size on strain. We measure the spontaneous curvature of GPMV membranes to be 2-10 μm-1 and weakly influenced by the 40× variation in MUC1 density, a conclusion we validate by performing independent experiments in which MUC1 is enzymatically removed from GPMVs. Overall, our study advances the understanding of heterogeneity in size and MUC1 density in GPMVs, and establishes single-vesicle-level methods for characterization of mechanical properties within a heterogeneous population of GPMVs. Furthermore, our measurements highlight differences between membrane properties of GPMVs and their parent cells.

Physiological and behavioral responses of the Baltic clam Macoma balthica to a laboratory simulated CO2-leakage from a subseabed carbon storage site.

Carbon capture and storage in sub-seabed geological reservoirs is now officially included in the atmospheric CO2 emissions reduction policy and meets the agenda of Sustainable Development Goals (SDGs). Over the last few years biological risk assessment studies have delivered substantial empirical data on possible consequences of CO2 leakages from underwater storage sites on benthic systems. Current knowledge on Carbon Capture and Storage CCS associated risks is limited to marine systems. Yet there are multiple areas identified as suitable for carbon storage, but their hydrogeochemical features are so distinct that they should be studied as separate cases. Baltic Sea is one example of an area but is host to a unique - in a world scale - ecosystem with low salinity in combination with reduced oxygen availability in the benthic zone. Geological surveys have designated a potential storage site in the Southern Baltic Sea, namely the B3 oil field. Thus, this study focuses on biological effects of seawater acidification caused by a simulated CO2 leakage scenarios under laboratory conditions on a model macrobenthic in-faunal species. Baltic clams Macoma balthica were exposed to different environmental pH scenarios: pH7.7 (no leakage), pH7.0 (moderate hypercapnia) and pH6.3 (severe hypercapnia) in three independent experiments conducted with the use of a hyperbaric tank (Karl Eric Titank) mimicking hydrostatic pressure of 900kPa, relevant to conditions at the B3 field. Selected physiological aspects of the Baltic clam, such as survival, shell growth rate, morphometric condition and biochemical composition were investigated along with their behavioral responses, i.e. sediment burrowing activity. The results showed modest effects of hypercapnia on physiological performance of the clams that did not lead to greater mortality in neither of the tested leakage scenarios. Apart from high survival of the clams even in the lowest seawater pH (6.3) there were only little changes observed in the burrowing depth of the clams and biochemical composition of their soft tissues related to seawater acidification. The most evident physiological responses of the clams to prolonged hypercapnia (40days at pH6.3) were manifested in decreased shell growth.

BASIC PRINCIPLES OF ORGANIZING RESEARCH AND RESEARCH ACTIVITIES DIRECTED TO FORMING RESEARCH SKILLS

The main principles of the formation of research activities in biological education and methodological features of implementation of project activities are analyzed in the research work. The use of active learning methods was systematized by using project tasks, laboratory works, interdisciplinary approaches and modern educational technologies. Ways of forming students' critical thinking, independent search for scientific information and the ability to analyze the results, as well as the ability to work with biological data and conduct independent experiments were studied. Based on the features of the factors contributing to increasing the level of learning motivation and deepening biological education, the principles of teaching were differentiated. Through the experiment of successful application of these methods in educational practice, their effectiveness in directing students to study and professional activities in the field of science has been proved.

Differential effects of photophase on the reproductive behaviour of two species of medico-legal relevance, Peckia (Peckia) chrysostoma (Wiedemann, 1830) and Peckia (Sarcodexia) lambens (Wiedemann, 1830) (Diptera: Sarcophagidae).

The nocturnal behaviour and reproduction patterns of Sarcophagidae species during the scotophase are largely unexplored for species in the Neotropical region. The aim of this study was to assess the light regimes under which females of Peckia (Peckia) chrysostoma (Wiedemann, 1830) and Peckia (Sarcodexia) lambens (Wiedemann, 1830) would larviposit and understand how these variables influence intrauterine development in these flies. The experiments were conducted in an experimental room (lux = 100) in two independent experiments: I. Larviposition test: Females mated with males of over 8 days old. II. Intrauterine development test: females over 8 days old and mated were individually isolated. Both experiments were performed under photophases (L:D) of 0:24, 6:18; 12:12; 18:6 and 24:0 for a period of 96 h. Larviposition occurred in total darkness for P. (P.) chrysostoma and P. (S.) lambens in all treatments, without significant differences among photophase treatments (p > 0.05). Photophase influenced the timing of larviposition, occurring as early as 24 h in 12:12 L:D conditions, while no larviposition was observed in the first 24 h in the 0:24 treatment for either species. The light duration significantly affected the percentage of gravid females of both species (p < 0.05), with higher percentages of gravid females in treatments of longer light duration. Females at the initial and intermediate stages of egg development were more strongly associated with treatments of continuous darkness (0:24) or short photophase (6:18), whereas females with an advanced stage of egg development were more prevalent in the 12:12 treatment. The implications of these findings for forensic entomology are profound, challenging conventional knowledge by revealing that necrophagous insects are not limited to diurnal activity patterns.

Juvenile resistance of zoned in the Russian Federation and promising triticale cultivars to leaf fungal diseases

Triticale is a grain crop developed by man as a result of crossing wheat and rye in order to combine the best traits of the parent species in a single organism. Fast introduction of triticale into practice and its wide spread cultivation is prevented by the fact that many commercial cultivars have high potential of productivity while varying in insufficient resistance to lodging and to a number of dangerous diseases. In 2023-2024 there was studied juvenile resistance to four fungal diseases (leaf rust, dark-brown leaf spot blotch, septoria blotch, powdery mildew) in 118 varieties from the register of the Russian Federation and promising triticale cultivars (winter and summer) included to the State Variety Testing over the past 5 years. The seedlings were infected with combined Puccinia triticina population, mixture of Bipolaris sorokiniana, Stagonospora nodorum and Blumeria graminis f. sp. tritici isolates collected in North-Western region of the Russian Federation. Disease resistance was evaluated according to the VIR methodology. By the results of one experiment, 93 samples of 118 were evaluated as resistant to powdery mildew. But according to the results of three independent experiments among winter and summer hexaploid triticale only 27 and 12 cultivars, respectively, were characterized by high juvenile resistance to powdery mildew. According to the results of the first experiment 10 samples were included into the class of leaf rust resistant. Only Pakhar winter cultivar was resistant to the disease according to the results of three independent experiments. All the samples of the research were highly susceptible to dark brown leaf spot blotch and septoriosis. Thus, among the triticale cultivars 39 were marked as powdery mildew resistant and 1 – as leaf rust resistant. They are of certain interest for breeding. It was also shown that for selection of reliable sources of resistance the plant material should be studied in not less than three independent experiments.

Unveiling the role of lipopolysaccharide-related genes in diabetic retinopathy: identification of key biomarkers and immune infiltration analysis

BackgroundGrowing evidence suggests a link between systemic lipopolysaccharide (LPS) exposure and worsening diabetic retinopathy (DR). This study aims to investigate DR’s pathogenesis by analyzing LPS-related genes (LRGs) through bioinformatics.MethodsThe CTD database was utilized to identify LRGs. The datasets associated with DR were acquired from the GEO database. The Venn diagram was used to identify the differentially expressed LRGs (DLRGs), and the putative molecular mechanism of these DLRGs was investigated through functional enrichment analysis. We used WGCNA, Lasso regression, and RF to identify hub DLRGs. The expression levels of these hub DLRGs were validated in an independent dataset (GSE102485) and cell experiments. Employing the CIBERSORT algorithm, we examined the infiltration of 22 distinct immune cell types in DR and assessed the association between key DLRGs and immune infiltrates through correlation analysis.ResultsA total of 71 DLRGs were detected. These genes exhibited significant enrichment in pathways associated with inflammation. In addition, the in-depth analysis uncovered that five hub DLRGs (STK33 and EPHX2) linked to bacterial LPS displayed noteworthy diagnostic potential for individuals diagnosed with DR. The hub DLRGs expression in the high glucose-induced DR model was confirmed by qRT-PCR analysis. Furthermore, examination of immune infiltration indicated a significant association between these five genes and the extent of immune cell infiltration.ConclusionSTK33 and EPHX2 serve as biomarkers related to bacterial LPS. Exploring these genes in-depth could provide innovative ideas and a foundation for comprehending the progression of the disease and developing targeted treatments for DR.

Genetic Mapping of the Powdery Mildew Resistance Gene Pm13 on Oat (Avena sativa) Chromosome 1D

ABSTRACTPowdery mildew, caused by the biotrophic fungus Blumeria graminis DC. f. sp. avenae, is a widespread disease of oats, especially in the temperate regions of Western and Central Europe, and the use of resistant varieties is the most sustainable way to ensure stable yields. Therefore, the identification of robust and effective resistance to powdery mildew is of great interest for oat breedinpg. In contrast to race‐specific resistance genes, adult plant resistance (APR) is generally considered to be more durable. The oat variety ‘Firth’, as well as related varieties such as ‘Husky’ or ‘Flämingstip’, contains an unknown APR gene, which was previously located on chromosome 1D using DArT markers. The aim of this study was to confirm and refine the chromosomal location of this resistance gene, tentatively named Pm13. To this end, two independent experiments were carried out using different genetic material under natural infection conditions in the field: genome‐wide association mapping (GWAS) in a diverse set of 250 oat lines grown in 10 environments and QTL mapping in a HuskyxAVE1284 biparental population grown in three environments. Both approaches identified a QTL for powdery mildew resistance on the distal end of chromosome 1D in the hexaploid Sang oat genome. The locus explained up to 15% of the phenotypic variance in GWAS and 64% of the phenotypic variance in QTL mapping. Comparison of field data with results from laboratory leaf segment tests confirmed that Pm13 does indeed confer APR. The sequence information of the identified linked markers may allow the development of molecular markers useful for early selection of oat lines with high levels of APR.

Independent Genetic Mapping Experiments Identify Diverse Molecular Determinants of Host Adaptation in a Generalist Herbivore.

Interactions between plants and herbivores promote evolutionary change. Studying the evolution of herbivore mechanisms aimed to cope with different host plant species is a critical intersection between evolutionary biology and sustainable pest management. Generalist herbivores are of particular interest, as hybridization between genetically distinct populations can increase the standing genetic variation and therefore the adaptive potential of the species. Tetranychus urticae is a generalist arthropod known for its adaptive potential, evidenced in its immense host range and ability to develop metabolic resistance to xenobiotics. However, the molecular underpinnings associated with the potential of host adaptation and the consequences of host adaptation in this, and many other pests remain elusive. Here, we use two independent, empirical approaches to identify and map the genetic basis of host plant performance and adaptation in genetically distinct populations of T. urticae. In the first approach, we subject a genetically diverse mite population to tomato selection and map genomic regions linked to the phenotypic evolution of increased reproductive performance. In the second approach, we map genomic regions responsible for performance on tomato by comparing the genomes of pooled individuals from an F2 backcross between populations with high and low reproductive performance. Both approaches revealed specific and shared genomic regions associated with host plant performance and adaptation and key candidate genes were identified. Our findings highlight the power of spider mite genetic approaches to identify the complex genetic basis of host adaptation in generalist herbivores.

Incidental Vocabulary Acquisition Through Captioned Viewing: A Meta‐Analysis

AbstractSecond language (L2) viewing with captions (i.e., L2 on‐screen text) is now a proliferating as well as promising area of L2 acquisition research. The goal of the present meta‐analysis was to examine (a) the relationship between captioned viewing and incidental vocabulary learning and (b) what variables related to learners, treatment, methodology, and vocabulary tests moderate the captioning effect. Synthesizing 89 effect sizes from 49 primary studies (i.e., independent experiments), we fitted a multilevel meta‐analysis model with restricted maximum likelihood estimation to calculate the overall effect size based on a standardized mean difference of gain scores between captioned viewing and uncaptioned viewing groups. The results showed a medium effect of captioning on L2 vocabulary learning, g = 0.56, p &lt;.001. Moderator analysis indicated moderating effects of instructional level, target audience of video materials, and administration of vocabulary pretest. These results are discussed with the aim of guiding future research and language learning through viewing.

Legitimize or Delegitimize? Mainstream Party Strategy toward (Former) Pariah Parties and How Voters Respond

Mainstream parties have often shifted from initially portraying new competitors as undemocratic pariahs (i.e., a delegitimizing strategy) to portraying the same parties later as democratic (i.e., a legitimizing strategy). I argue that voters follow mainstream parties’ legitimizing strategies in their legitimacy evaluations of these parties. I investigate this argument with two independent survey experiments and a quantitative media content analysis in two countries that differ sharply in the nature of party competition—from mainstream parties delegitimizing a far-right party (i.e., Germany) to mainstream parties legitimizing it (i.e., Sweden). I find strong evidence that (a) mainstream parties can effectively legitimize pariah parties in the eyes of voters, (b) turning back to delegitimization has little effect, (c) legitimization is no less effective in the face of a third party’s delegitimizing strategy, and (d) legitimization resonates beyond co-partisans. The results suggest that mainstream party legitimization of pariah parties has far-reaching consequences.

Big brother: the effects of surveillance on fundamental aspects of social vision.

Despite the dramatic rise of surveillance in our societies, only limited research has examined its effects on humans. While most research has focused on voluntary behaviour, no study has examined the effects of surveillance on more fundamental and automatic aspects of human perceptual awareness and cognition. Here, we show that being watched on CCTV markedly impacts a hardwired and involuntary function of human sensory perception-the ability to consciously detect faces. Using the method of continuous flash suppression (CFS), we show that when people are surveilled (N = 24), they are quicker than controls (N = 30) to detect faces. An independent control experiment (N = 42) ruled out an explanation based on demand characteristics and social desirability biases. These findings show that being watched impacts not only consciously controlled behaviours but also unconscious, involuntary visual processing. Our results have implications concerning the impacts of surveillance on basic human cognition as well as public mental health.

Multiscale computational model predicts how environmental changes and treatments affect microvascular remodeling in fibrotic disease.

Investigating the molecular, cellular, and tissue-level changes caused by disease, and the effects of pharmacological treatments across these biological scales, necessitates the use of multiscale computational modeling in combination with experimentation. Many diseases dynamically alter the tissue microenvironment in ways that trigger microvascular network remodeling, which leads to the expansion or regression of microvessel networks. When microvessels undergo remodeling in idiopathic pulmonary fibrosis (IPF), functional gas exchange is impaired and lung function declines. We integrated a multiscale computational model with independent experiments to investigate how combinations of biomechanical and biochemical cues in IPF alter cell fate decisions leading to microvascular remodeling. Our computational model predicted that extracellular matrix (ECM) stiffening reduced microvessel area, which was accompanied by physical uncoupling of endothelial cell (EC) and pericytes, the cells that comprise microvessels. Nintedanib, an Food and Drug Administration-approved drug for treating IPF, was predicted to further potentiate microvessel regression by decreasing the percentage of quiescent pericytes while increasing the percentage of pericytes undergoing pericyte-myofibroblast transition in high ECM stiffnesses. Importantly, the model suggested that YAP/TAZ inhibition may overcome the deleterious effects of nintedanib by promoting EC-pericyte coupling and maintaining microvessel homeostasis. Overall, our combination of computational and experimental modeling can predict and explain how cell decisions affect tissue changes during disease and in response to treatments.

Kinetic Modelling of Ralstonia eutropha H16 Growth on Different Substrates

Due to environmental pollution and the depletion of fossil fuels, there is growing interest in the development and use of biofuels as environmentally friendly alternatives. One of the most promising biofuels is biohydrogen, hydrogen produced through sustainable processes using microorganisms such as bacteria and algae. One of the most interesting bacteria for hydrogen production is Ralstonia eutropha H16, known for its ability to produce oxygen-tolerant hydrogenases. These enzymes play a crucial role in biohydrogen metabolism and production. The aim of this work was to determine the optimal conditions (reactor type and synthetic medium composition) for the cultivation of R. eutropha H16. The culture media contained different concentrations of fructose and glycerol (mono- or double-substrate cultivation) and the experiments were carried out in a batch reactor. The initial experiments were carried out with 4 g/L fructose or glycerol in the culture medium at pH 7, T = 30 °C, and 120 rpm. The mathematical model, consisting of the growth kinetics (described by the Monod’s model) and the corresponding mass balances, was proposed. The developed model was validated using two independent experiments with different initial substrate concentrations: 2 g/L glycerol and fructose in one medium and 4 g/L fructose and 1 g/L glycerol in the second. In order to propose the optimal cultivation procedure for future research, the mathematical model simulations were performed for different reactor types (batch, fed-batch, and continuous stirred tank reactors) and different initial substrate concentrations. The most successful experiment was the one with 4 g/L glycerol, where γX = 0.485 ± 0.001 g/L of biomass was achieved. Further calculations showed that the most biomass would be produced at higher glycerol concentrations (at γG = 6.358 g/L, γX = 1.311 g/L should be achieved after 200 h of cultivation) and when using a fed-batch reactor (γX = 0.944 g/L after 200 h of cultivation).