Cell Concentration Research Articles

Infection spreading in tissue as a reaction-diffusion wave.

Viral infection develops in the organism due to virus replication inside infected cells and its transmission from infected to uninfected cells through the extracellular matrix or cell junctions. In this work, we model infection spreading in tissue with a delay reaction-diffusion system of equations for the concentrations of uninfected cells, infected cells and virus. We prove the wave existence, determine its speed of propagation and introduce a simplified one-equation model obtained from the complete model using a quasi-stationary approximation.

Hydrogel-chitosan and polylactic acid-polycaprolactone bioengineered scaffolds for reconstruction of mandibular defects: a preclinical in vivo study with assessment of translationally relevant aspects

Background: Reconstruction of mandibular bone defects is a surgical challenge, and microvascular reconstruction is the current gold standard. The field of tissue bioengineering has been providing an increasing number of alternative strategies for bone reconstruction.Methods: In this preclinical study, the performance of two bioengineered scaffolds, a hydrogel made of polyethylene glycol-chitosan (HyCh) and a hybrid core-shell combination of poly (L-lactic acid)/poly (ε-caprolactone) and HyCh (PLA-PCL-HyCh), seeded with different concentrations of human mesenchymal stromal cells (hMSCs), has been explored in non-critical size mandibular defects in a rabbit model. The bone regenerative properties of the bioengineered scaffolds were analyzed by in vivo radiological examinations and ex vivo radiological, histomorphological, and immunohistochemical analyses.Results: The relative density increase (RDI) was significantly more pronounced in defects where a scaffold was placed, particularly if seeded with hMSCs. The immunohistochemical profile showed significantly higher expression of both VEGF-A and osteopontin in defects reconstructed with scaffolds. Native microarchitectural characteristics were not demonstrated in any experimental group.Conclusion: Herein, we demonstrate that bone regeneration can be boosted by scaffold- and seeded scaffold-reconstruction, achieving, respectively, 50% and 70% restoration of presurgical bone density in 120 days, compared to 40% restoration seen in spontaneous regeneration. Although optimization of the regenerative performance is needed, these results will help to establish a baseline reference for future experiments.

Modeling the mechanosensitive collective migration of cells on the surface and the interior of morphing soft tissues.

Cellular contractility, migration, and extracellular matrix (ECM) mechanics are critical for a wide range of biological processes including embryonic development, wound healing, tissue morphogenesis, and regeneration. Even though the distinct response of cells near the tissue periphery has been previously observed in cell-laden microtissues, including faster kinetics and more prominent cell-ECM interactions, there are currently no models that can fully combine coupled surface and bulk mechanics and kinetics to recapitulate the morphogenic response of these constructs. Mailand et al. (Biophys J 117(5):975-986, 2019) had shown the importance of active elastocapillarity in cell-laden microtissues, but modeling the distinct mechanosensitive migration of cells on the periphery and the interior of highly deforming tissues has not been possible thus far, especially in the presence of active elastocapillary effects. This paper presents a framework for understanding the interplay between cellular contractility, migration, and ECM mechanics in dynamically morphing soft tissues accounting for distinct cellular responses in the bulk and the surface of tissues. The major novelty of this approach is that it enables modeling the distinct migratory and contractile response of cells residing on the tissue surface and the bulk, where concurrently the morphing soft tissues undergo large deformations driven by cell contractility. Additionally, the simulation results capture the changes in shape and cell concentration for wounded and intact microtissues, enabling the interpretation of experimental data. The numerical procedure that accounts for mechanosensitive stress generation, large deformations, diffusive migration in the bulk and a distinct mechanism for diffusive migration on deforming surfaces is inspired from recent work on bulk and surface poroelasticity of hydrogels involving elastocapillary effects, but in this work, a two-field weak form is proposed and is able to alleviate numerical instabilities that were observed in the original method that utilized a three-field mixed finite element formulation.

Tirbanibulin decreases cell proliferation and downregulates protein expression of oncogenic pathways in human papillomavirus containing HeLa cells.

Tirbanibulin 1% ointment is a synthetic antiproliferative agent approved in 2021 by the European Union for treating actinic keratoses (AK). Topical tirbanibulin has clinically resolved HPV-57 ( +) squamous cell carcinoma (SCC), HPV-16 ( +) vulvar high-grade squamous intraepithelial lesion, epidermodysplasia verruciformis, and condyloma. We examined how tirbanibulin might affect HPV oncoprotein expression and affect other cellular pathways involved in cell proliferation and transformation. We treated the HeLa cell line, containing integrated HPV-18, with increasing doses of tirbanibulin to determine the effects on cell proliferation. Immunoblotting was performed with antibodies against theSrc canonical pathway, HPV 18 E6 and E7 transcription regulation, apoptosis, and invasion and metastasis pathways. Cell proliferation assays with tirbanibulin determined the half-maximal inhibitory concentration (IC50) of HeLa cells to be 31.49nmol/L. Increasing concentrations of tirbanibulin downregulates the protein expression of Src(p < 0.001), phospho-Src(p < 0.001), Ras(p < 0.01), c-Raf(p < 0.001), ERK1(p < 0.001), phospho-ERK1(p < 0.001), phospho-ERK2(p < 0.01), phospho-Mnk1(p < 0.001), eIF4E(p < 0.01), phospho-eIF4E(p < 0.001), E6(p < 0.01), E7(p < 0.01), Rb(p < 0.01), phospho-Rb(p < 0.001), MDM2(p < 0.01), E2F1(p < 0.001), phospho-FAK(p < 0.001), phospho-p130 Cas(p < 0.001), Mcl-1(p < 0.01), and Bcl-2(p < 0.001), but upregulates cPARP(p < 0.001), and cPARP/fPARP(p < 0.001). These results demonstrate that tirbanibulin may impact expression of HPV oncoproteins via the Src- MEK- pathway. Tirbanibulin significantly downregulates oncogenic proteins related to cell cycle regulation and cell proliferation while upregulating apoptosis pathways.

Improving the stability of spray-dried probiotic acerola juice: A study on hydrocolloids' efficacy and process variables

This study explores the optimization of spray drying conditions for fermented acerola juice powder, focusing on nutrient retention and probiotic viability. Acerola, a fruit high in vitamin C and phenolics, was fermented under varying conditions to support the growth of Lactobacillus gasseri. The fermentation of acerola juice was conducted at pH levels of 3.2(in natura), 5.0, and 7.0 to promote optimal bacterial growth. Spray drying was then performed at inlet temperatures of 120°C, 140°C, and 160°C, using varying concentrations of maltodextrin and gelatin as encapsulants. The powders were analyzed for vitamin C, phenolic content, and Lactobacillus gasseri cell concentration. Optimal bacterial growth occurred at pH 7.0. The spray drying process showed that lower temperatures (120°C) favored higher vitamin C (up to 6.2 mg/g) and phenolic retention (up to 59.9 mg/g), while higher temperatures (160°C) enhanced probiotic survival (up to 8.3 × 108 CFU/g). Hydrocolloids like maltodextrin and gelatin were crucial in enhancing nutrient and probiotic stability, showcasing their importance in optimizing spray-dried functional food formulations. Tailoring fermentation and spray drying conditions is crucial in producing functional fruit powders with high nutritional and probiotic value.

In vitro cultivation of adherent cells on microscope slides for downstream applications

In vitro studies with cultured cells are often conducted as an important part of basic research. Adherent cells are typically cultivated in flasks or trays, for which cell staining and subsequent visualization become impractical. We here present a simple step-by-step method for growing adherent cells directly on glass microscope slides, using low-cost equipment readily available in most laboratories. Most parameters such as type of microscope slide (e.g. surface coating), cell seeding concentrations and incubation times can be adjusted according to cell line characteristics and experimental aims, reflecting the methods’ flexibility. Through our experiments, microscope slides proved to provide an acceptable surface for cell adhesion and growth of the tested cell lines, as well as being robust and functional with respect to downstream procedures. The method can potentially be combined with different techniques for visualization of experimental effects, such as histological staining methods, fluorescent staining, and immunochemistry. In our method development we have successfully cultivated three different cell lines directly on microscope slides – Atlantic salmon kidney cells (ASK), rainbow trout gill cells (RTgill-W1), and human cancerous lung cells (A549) – and subjected them to various experimental treatments. Finally, as proof-of-concept we provide examples of successful histological staining of the fixed cells.Experimental design in short:• Cultivate cells and calculate cell concentration• Seed a small volume of growth medium with an appropriate number of cells on microscope slide in an area confined by hydrophobic marker• Let cells adhere over night before adding more growth medium or directly conducting experiments and fixing cells for downstream applications

P-373 Melatonin and chemotherapy: does the proposed fertoprotective agent impair the anti-tumor effects of cancer therapy?

Abstract Study question Does the proposed fertoprotective agent melatonin interfere with the anti-cancer activity of imatinib chemotherapy in a chronic myelogenous leukemia (CML) cell line? Summary answer At low concentrations, melatonin demonstrates mild inhibition of imatinib activity, however this is overcome at therapeutic concentrations. Melatonin also shows anti-tumor activity against CML. What is known already A harmful consequence of cancer therapy is a resultant loss of fertility. Pharmacologic interventions that reduce radiation or chemotherapy-induced gonadotoxicity are a major unmet medical need. Several ‘fertoprotective’ agents have shown promise in protecting the gonads from injury during treatment, including melatonin. However, melatonin is not currently applied in humans for this purpose. Key safety and efficacy data are needed to move potential fertoprotective agents into clinical trials. Study design, size, duration We evaluated the interaction of varying combined concentrations of melatonin and imatinib, a tyrosine kinase inhibitor, within an in-vitro matrix experiment. The interaction was be evaluated within K562, a cell line derived from human chronic myelogenous leukemia (CML). This chemotherapy and cell line were selected due to CML’s dependence on BCR-ABL for survival, which is inhibited by imatinib, permitting direct evaluation of melatonin-imatinib cross-interaction. Participants/materials, setting, methods K562 were seeded in 384-well plates into which increasing concentrations of imantinib and melatonin were progressively dispensed. The cells were cultured for 48 hours. Viable cell concentrations were then determined using a cell luminescent assay. Drug interaction was then determined using drug synergy analysis software.The expected drug combination responses were calculated based on ZIP reference model using SynergyFinder 3.0. Deviations between observed and expected responses with positive and negative values denote synergy and antagonism respectively. Main results and the role of chance Melatonin demonstrated toxicity to K562 CML cell lines independent of imatinib, with a mean inhibition of cell growth of 74.7% at 1uM, CI [69.6%, 79.7%]. This anti-tumor activity was progressively seen at concentrations &amp;gt;0.1 uM. At low imatinib concentrations (&amp;lt;0.2 uM), melatonin decreased the anti-cancer potency of imatinib. This effect was overcome at higher concentrations of imatinib. The overall mean synergy score was -5.87, CI [-7.145, -4.588]. Limitations, reasons for caution These experiments were carried out in an in-vitro setting in a tightly controlled environment. In a clinical setting, the complexity of potential interactions between melatonin and chemotherapy will increase (i.e. metabolism, distribution), thus animal models will be a necessary next step of evaluation before clinical safety trials may proceed. Wider implications of the findings Melatonin may serve as an inexpensive, well-tolerated adjuvant to help protect the gonad from chemotherapy, while additionally exhibiting its own anti-cancer effects in certain settings. Our preliminary data suggests that the risk of melatonin to impair active imatinib treatment may be low, however continued investigation is necessary. Trial registration number Not applicable

P-306 GnRH agonists exert a positive influence on regulatory immune cells in the endometrium of women with adenomyosis

Abstract Study question How does treatment with GnRH-agonist (GnRH-a) prior to frozen embryo transfer (FET) in women with adenomyosis affect immune cell populations in endometrium and peripheral blood? Summary answer GnRH-a induces a decrease in monocytes and an increase in CD4+T-cells in peripheral blood and a decrease classical monocytes and T-regulatory cells in the endometrium What is known already Adenomyosis is associated with lower implantation and higher miscarriage rates. Observational studies have reported improved pregnancy outcomes in women with adenomyosis after assisted reproductive technologies (ART) and pre-treatment with GnRH-a prior to FET. However, the specific mechanisms of GnRHa action beyond central hormonal suppression remain unclear, but may be mediated through local and/or systemic immunomodulation. Study design, size, duration Prospective cohort study including infertile women with adenomyosis and GnRH-a treatment ≥3 months prior to FET. Pre- and post-treatment analysis of blood and endometrium samples were compared. Recruitment is ongoing with n = 30 women included thus far, 16 of whom have completed the study, while the remaining are still undergoing GnRH-a therapy. Participants/materials, setting, methods Adenomyosis was diagnosed sonographically if ≥ 2 criteria published by the MUSA group were met. Peripheral blood and endometrial samples were obtained before and after treatment with GnRH-a. Plasma cells and uterine Natural Killer (uNK) cells in endometrial biopsies were quantified with immunhistochemistry (IHC), and leukocyte populations in all samples were analysed using flow cytometry (FC). Pre- and post-treatment levels of immune cells and percentage of leukocyte populations were compared using Wilcoxon rank-sum tests (p &amp;lt; 0.05 significant) Main results and the role of chance Interim analysis of immune cell populations in peripheral blood and endometrium of the 16 women who already completed the study was performed. At baseline, IHC showed elevated plasma cell concentrations indicating chronic endometritis in 3/30 patients (10%), while uNK cells were elevated (&amp;gt;300/mm2) in 13/30 patients (43.3%). FC analysis of peripheral blood showed a significant decrease in percentage of monocytes (p = 0.01) and increase in percentage of T-cells (p = 0.03), specifically concentration of CD4+T-cells (p = 0.03), after treatment with GnRH-a as compared to pre-treatment levels. In the endometrium, following GnRH-a therapy, we observed a decrease in both the percentage of classical monocytes (p = 0.03) and T-regulatory cells (p = 0.03). All 16 participants who completed the study already underwent FET, resulting in ten pregnancies (62.5%), although four resulted in miscarriage, while the outcome of the remaining pregnancies is still pending. Limitations, reasons for caution These are preliminary results whose generalizability needs to be confirmed in a larger study population. No correction for multiple comparisons was performed and significant findings have to be interpreted with caution. Wider implications of the findings Elevated uNK on IHC cells seen at baseline may be associated with implantation failure, miscarriage. CD4+ and DN T-cells are important mediators of reproductive immune tolerance. In women with adenomyosis, GnRH-a may have a positive impact on these regulatory immune cells in peripheral blood as well as in the endometrium. Trial registration number Not applicable

A high-throughput assay identifies molecules with antimicrobial activity against persister cells.

Introduction. Persister cells are transiently non-growing antibiotic-tolerant bacteria that cause infection relapse, and there is no effective antibiotic therapy to tackle these infections.Gap statement. High-throughput assays in drug discovery are biased towards detecting drugs that inhibit bacterial growth rather than killing non-growing bacteria. A new and simple assay to discover such drugs is needed.Aim. This study aims to develop a simple and high-throughput assay to identify compounds with antimicrobial activity against persister cells and use it to identify molecular motifs with such activity.Methodology. We quantified Staphylococcus aureus persister cells by enumeration of colony forming units after 24 h ciprofloxacin treatment. We first quantified how the cell concentration, antibiotic concentration, growth phase and presence/absence of nutrients during antibiotic exposure affected the fraction of persister cells in a population. After optimizing these parameters, we screened the antimicrobial activity of compound fragments to identify molecular structures that have activity against persister cells.Results. Exponential- and stationary-phase cultures transferred to nutrient-rich media displayed a bi-phasic time-kill curve and contained 0.001-0.07% persister cells. A short rifampicin treatment resulted in 100% persister cells for 7 h, after which cells resumed activity and became susceptible. Stationary-phase cultures displayed a low but constant death rate but ultimately resulted in similarly low survival rates as the exponential-phase cultures after 24 h ciprofloxacin treatment. The persister phenotype was only maintained in most of the population for 24 h if cells were transferred to a carbon-free minimal medium before exposure to ciprofloxacin. Keeping cells starved enabled the generation of high concentrations of S. aureus cells that tolerate 50× MIC ciprofloxacin, and we used this protocol for rapid screening for biocidal antibiotics. We identified seven compounds from four structural clusters with activity against antibiotic-tolerant S. aureus. Two compounds were moderately cytotoxic, and the rest were highly cytotoxic.Conclusion. Transferring a stationary-phase culture to a carbon-free minimal medium for antimicrobial testing is a simple strategy for high-throughput screening for new antibiotics that kill persister cells. We identified molecule fragments with such activity, but further screening is needed to identify motifs with lower general cytotoxicity.

New solutions of time-fractional cancer tumor models using modified He-Laplace algorithm

Cancer develops through cells when mutations build up in different genes that control cell proliferation. To treat these abnormal cells and minimize their growth, various cancer tumor samples have been modeled and analyzed in literature. The current study is focused on the investigation of more generalized cancer tumor model in fractional environment, where net killing rate is taken into account in different domains. Three types of killing rates are considered in the current study including time and position dependent killing rates, and concentration of cells based killing rate. A hybrid mechanism is proposed in which different homotopies are used with perturbation technique and Laplace transform. This leads to a convenient algorithm to tackle all types of fractional derivatives efficiently. The convergence and error bounds of the proposed scheme are computed theoretically by proving related theorems. In the next phase, convergence and validity is analyzed numerically by calculating residual errors round the fractional domain. It is observed that computed errors are very less in the entire fractional domain. Moreover, comparative analysis of Caputo, Caputo-Fabrizio (CF), and Atangana–Baleanu (AB) fractional derivatives is also performed graphically to discern the effect of different fractional approaches on the solution profile. Analysis asserts the reliability of proposed methodology in the matter of intricate fractional tumor models, and hence can be used to other complex physical phenomena.

In vitro cultivation of adherent cells on microscope slides for downstream applications

In vitro studies with cultured cells are often conducted as an important part of basic research. Adherent cells are typically cultivated in flasks or trays, for which cell staining and subsequent visualization become impractical. We here present a simple step-by-step method for growing adherent cells directly on glass microscope slides, using low-cost equipment readily available in most laboratories. Most parameters such as type of microscope slide (e.g. surface coating), cell seeding concentrations and incubation times can be adjusted according to cell line characteristics and experimental aims, reflecting the methods’ flexibility. Through our experiments, microscope slides proved to provide an acceptable surface for cell adhesion and growth of the tested cell lines, as well as being robust and functional with respect to downstream procedures. The method can potentially be combined with different techniques for visualization of experimental effects, such as histological staining methods, fluorescent staining, and immunochemistry. In our method development we have successfully cultivated three different cell lines directly on microscope slides – Atlantic salmon kidney cells (ASK), rainbow trout gill cells (RTgill-W1), and human cancerous lung cells (A549) – and subjected them to various experimental treatments. Finally, as proof-of-concept we provide examples of successful histological staining of the fixed cells.Experimental design in short:• Cultivate cells and calculate cell concentration• Seed a small volume of growth medium with an appropriate number of cells on microscope slide in an area confined by hydrophobic marker• Let cells adhere over night before adding more growth medium or directly conducting experiments and fixing cells for downstream applications

Purification of a chemotherapeutic agent, L-Arginase, from Pseudomonas aeruginosa isolated from soil.

L. arginase refers to the enzyme arginase found in the genus Lactobacillus, it plays a crucial role in the urea cycle, and has implications in various biological applications. This study aimed to purify arginase from Pseudomonas aeruginosa, isolated from soil, and apply it as an anticancer. 28 soil samples of P. aeruginosa were collected from different places of Baghdad, and rice lands in Najaf and Diwaniyah governorates. Different standard laboratory and biochemical assays, and Vitik system were used in diagnosis and growth of arginase enzyme under certain pH, temperature, incubation period. The purified enzyme was precipitated by ammonium sulfite (60-80%), dialyses bag 8000-1000KD, ion exchange by DEAE cellulose and sephadex G100 in gel filtration. Cytotoxicity of arginase against breast t cancer AJM-13 and rat embryo fibroblast REF normal cell line was evaluated for (48 and 72 hours). The inhibition rate increased in the low concentration of abnormal cell (AMJ-13) while decreased in the normal cell (REF), this study takes different concentration (0.392-12.5mg/mL), and low concentration (1562-0.048 mg/mL), the result in high concentration was IR 54.7% during 72 hours for AJM-13 and 14.3% for REF in the same time, while the low concentration was IR 91% in the 1562 mg/mL in the AMJ-13, and 51% in ERF, LD50 of arginase enzyme was 0.781 mg/mL that 41% during 72 hours for ERF, its save to normal cells. Arginase enzyme, at low concentrations, may have an inhibitory effect on cancer cells, and simultaneously, protect normal cell lines.

Parametric study on the margination of white blood cells (WBCs) in a passive microfluidic device

From fundamental research exploring molecular mechanisms to advanced endeavours like the development of artificial white blood cells, white blood cells have widespread applications due to their crucial role in safeguarding the body, defending against infection, and eliminating external pathogens, serving as indicators of several diseases. So, white blood cells must be separated efficiently with high purity to make the passive microdevices more effective for diagnostic applications. In this study, we investigated how cell concentration and viscosity collectively impact the margination of white blood cells in an inertial flow microchannel. We aim to improve white blood cell separation efficiency in microfluidic devices. Unlike previous studies that examined individual factors, this research focused on the interplay between bio-physical properties like cell interaction and viscosity. To explore their correlation, we diluted the blood with phosphate-buffered saline and viscoelastic fluid to manipulate the viscosity and cell concentration. Viscoelastic fluid improved white blood cells margination, while higher viscosity and low cell concentration decreased it. Maintaining blood-like viscosity, optimizing cell-free layer width, and promoting cell-cell interaction in the focusing zone collectively enhanced white blood cells margination.

β-hydroxybutyrate resensitizes colorectal cancer cells to oxaliplatin by suppressing H3K79 methylation in vitro and in vivo

BackgroundKetone β-hydroxybutyrate (BHB) has been reported to prevent tumor cell proliferation and improve drug resistance. However, the effectiveness of BHB in oxaliplatin (Oxa)-resistant colorectal cancer (CRC) and the underlying mechanism still require further proof.MethodsCRC-Oxa-resistant strains were established by increasing concentrations of CRC cells to Oxa. CRC-Oxa cell proliferation, apoptosis, invasion, migration, and epithelial-mesenchymal transition (EMT) were checked following BHB intervention in vitro. The subcutaneous and metastasis models were established to assess the effects of BHB on the growth and metastasis of CRC-Oxa in vivo. Eight Oxa responders and seven nonresponders with CRC were enrolled in the study. Then, the serum BHB level and H3K79me, H3K27ac, H3K14ac, and H3K9me levels in tissues were detected. DOT1L (H3K79me methyltransferase) gene knockdown or GNE-049 (H3K27ac inhibitor) use was applied to analyze further whether BHB reversed CRC-Oxa resistance via H3K79 demethylation and/or H3K27 deacetylation in vivo and in vitro.ResultsFollowing BHB intervention based on Oxa, the proliferation, migration, invasion, and EMT of CRC-Oxa cells and the growth and metastasis of transplanted tumors in mice were suppressed. Clinical analysis revealed that the differential change in BHB level was associated with drug resistance and was decreased in drug-resistant patient serum. The H3K79me, H3K27ac, and H3K14ac expressions in CRC were negatively correlated with BHB. Furthermore, results indicated that H3K79me inhibition may lead to BHB target deletion, resulting in its inability to function.Conclusionsβ-hydroxybutyrate resensitized CRC cells to Oxa by suppressing H3K79 methylation in vitro and in vivo.

Microfluidic Platform with Precisely Controlled Hydrodynamic Parameters and Integrated Features for Generation of Microvortices to Accurately Form and Monitor Biofilms in Flow.

Microorganisms often live in habitats characterized by fluid flow, and their adhesion to surfaces in industrial systems or clinical settings may lead to pipe clogging, microbially influenced corrosion, material deterioration, food spoilage, infections, and human illness. Here, a novel microfluidic platform was developed to investigate biofilm formation under precisely controlled (i) cell concentration, (ii) temperature, and (iii) flow conditions. The developed platform central unit is a single-channel microfluidic flow cell designed to ensure ultrahomogeneous flow and condition in its central area, where features, e.g., with trapping properties, can be incorporated. In comparison to static and macroflow chamber assays for biofilm studies, microfluidic chips allow in situ monitoring of biofilm formation under various flow regimes and have better environment control and smaller sample requirements. Flow simulations and experiments with fluorescent particles were used to simulate bacteria flow in the platform cell for calculating flow velocity and direction at the microscale level. The combination of flow analysis and fluorescent strain injection in the cell showed that microtraps placed at the center of the channel were efficient in capturing bacteria at determined positions and to study how flow conditions, especially microvortices, can affect biofilm formation. The microfluidic platform exhibited improved performances in terms of homogeneity and robustness for in vitro biofilm formation. We anticipate the presented platform to be suitable for broad, versatile, and high-throughput biofilm studies at the microscale level.

Eco-evolutionary dynamics of cooperative antimicrobial resistance in a population of fluctuating volume and size

Antimicrobial resistance to drugs (AMR), a global threat to human and animal health, is often regarded as resulting from cooperative behaviour. Moreover, microbes generally evolve in volatile environments that, together with demographic fluctuations (birth and death events), drastically alter population size and strain survival. Motivated by the need to better understand the evolution of AMR, we study a population of time-varying size consisting of two competing strains, one drug-resistant and one drug-sensitive, subject to demographic and environmental variability. This is modelled by a binary carrying capacity randomly switching between mild and harsh environmental conditions, and driving the fluctuating volume (total amount of nutrients and antimicrobials at fixed concentration), and thus the size of the community (number of resistant and sensitive cells). We assume that AMR is a shared public good when the concentration of resistant cells exceeds a fixed concentration cooperation threshold, above which the sensitive strain has a growth advantage, whereas resistant cells dominate below it. Using computational means, and devising an analytical treatment (built on suitable quenched and annealed averaging procedures), we fully characterise the influence of fluctuations on the eco-evolutionary dynamics of AMR, and notably obtain specific strain fixation and long-lasting coexistence probabilities as a function of the environmental variation rate and cooperation threshold. We find that microbial strains tend to coexistence, but demographic fluctuations eventually lead to the extinction of resistant or sensitive cells for small or large values of the concentration cooperation threshold, respectively. This also holds for dynamic environments, whose specific properties determine the extinction timescale.

PAR1-mediated Non-periodical Synchronized Calcium Oscillations in human Mesangial Cells.

Mesangial cells offer structural support to the glomerular tuft and regulate glomerular capillary flow through their contractile capabilities. These cells undergo phenotypic changes, such as proliferation and mesangial expansion, resulting in abnormal glomerular tuft formation and reduced capillary loops. Such adaptation to the changing environment is commonly associated with various glomerular diseases, including diabetic nephropathy and glomerulonephritis. Thrombin-induced mesangial remodeling was found in diabetic patients, and expression of the corresponding protease-activated receptors (PARs) in the renal mesangium was reported. However, the functional PAR-mediated signaling in mesangial cells was not examined. This study investigated protease-activated mechanisms regulating mesangial cell calcium waves that may play an essential role in the mesangial proliferation or constriction of the arteriolar cells. Our results indicate that coagulation proteases like thrombin induce synchronized oscillations in cytoplasmic Ca2+ concentration of mesangial cells. The oscillations required PAR1 GPCRs-related activation, but not a PAR4, and were further mediated presumably through store-operated calcium entry and TRPC3 channel activity. Understanding thrombin signaling pathways and their relation to mesangial cells' contractile or synthetic (proliferative) phenotype may play a role in the development of chronic kidney disease and requires further investigation.

A ratiometric SERS strategy for the prediction of cancer cell proportion and guidance of glioma surgical resection

Rapid and accurate identification of tumor boundaries is critical for the cure of glioma, but it is difficult due to the invasive nature of glioma cells. This paper aimed to explore a rapid diagnostic strategy based on a label-free surface-enhanced Raman scattering (SERS) technique for the quantitative detection of glioma cell proportion intraoperatively. With silver nanoparticles as substrate, an in-depth SERS analysis was performed on simulated clinical samples containing normal brain tissue and different concentrations of patient-derived glioma cells. The results revealed two universal characteristic peaks of 655 and 717 cm−1, which strongly correlated with glioma cell proportion regardless of individual differences. Based on the intensity ratio of the two peaks, a ratiometric SERS strategy for the quantification of glioma cells was established by employing an artificial neuron network model and a polynomial regression model. Such a strategy accurately estimated the proportion of glioma cells in simulated clinical samples (R2 = 0.98) and frozen samples (R2 = 0.85). More importantly, it accurately facilitated the delineation of tumor margins in freshly obtained samples. Taken together, this SERS-based method ensured a rapid and more detailed identification of tumor margins during surgical resection, which could be beneficial for intraoperative decision-making and pathological evaluation.

Recent Advances in the Understanding of Stress Resistance Mechanisms in Probiotics: Relevance for the Design of Functional Food Systems.

In recent years, more and more scientific community, food producers, and food industry show increased interest in functional foods containing probiotics, which is a big challenge. The consumption of probiotics in the context of a balanced diet through the consumption of functional foods or through the intake of pharmaceutical preparations has proven to contribute to the improvement of human health, even contributing to the prevention of diseases. In order for probiotics to be considered suitable for consumption, they must contain a minimum concentration of viable cells, namely, at least 107 colony forming units of beneficial microbes per gram. Ensuring the viability of bacterial cells until the moment of consumption is the overriding priority of functional probiotic food manufacturers. Probiotic bacteria are subject to stress conditions not only during food manufacturing but also during gastrointestinal passage, which limit or even compromise their functionality. This paper first examines all the stressful conditions faced by probiotic cells in their production stages and related to the conditions present in the bioreactor fermentation and drying processes as well as factors related to the food matrix and storage. The stress situations faced by probiotic microorganisms during the gastrointestinal transit especially during stomach and intestinal residence are also analyzed. In order to understand the adaptation mechanisms of probiotic bacteria to gastrointestinal stress, intrinsic and adaptive mechanisms identified in probiotic strains in response to acid stress and to bile and bile acid stress are analyzed. In addition, improvement strategies for multiple stress tolerance of lactic acid bacteria through directions dealing with stress, accumulation of metabolites, use of protectants, and regulation of technological parameters are examined. Finally, the definition of postbiotics, inanimate microorganisms and/or their components conferring health benefits, is also introduced. Postbiotics include cell lysates, enzymes, and cell wall fragments derived from probiotic bacteria and may represent an alternative to the use of probiotics, when they do not tolerate stressful conditions.

Assessment of the digestibility, growth performance, hematological and serum biochemical profile of Bandjock Local Pigs (BLP) and Duroc X Large White pigs (DLW)

The study aimed to assess the digestibility, growth performance, and selected biochemical and hematological parameters of Bandjock Local pigs (BLP) and Duroc X Large White pigs (DLW). We hypothesize that the use of local ingredients in diet formulation associated to improved rearing conditions, enhance the growth performance, digestibility, biochemical and hematological parameters of BLP. The trial involved dividing twenty-four eight-week-old weaner pigs into two groups. Each group was randomly assigned to separate pig units. Animal management and feeding were consistent between both groups. The trial lasted for 120 days during which the growth performance, the digestibility of ingested nutrients, and biochemical and hematological parameters were evaluated. The results indicate that DLW pigs registered a weight gain (46.56±5.19 kg) significantly higher than BLP pigs (34.02), with a statistically similar feed conversion ratio. Except for albumin which was significantly higher in DLW and urea in BLP, there were no significant differences (p > 0.05) in total protein, cholesterol, globulin, triglycerides, creatinine, AST, and ALT as well as hematological parameters between the breeds. However, the exotic DLW had a relatively high mean blood platelets and white blood cell concentration. Although the fecal nitrogen was higher in BLP and the urinary nitrogen was lower in the DLW, there were significant differences (p < 0.05) for urine, fecal, and total excreted nitrogen in both breeds. The lowest scores in nutrient digestibility were recorded with BLP compared to DWL, except for crude fibers. The results of this study demonstrated that using diet formulated with local ingredients and improved rearing conditions, Cameroonian local indigenous pigs have a better productivity compared to exotic breeds. It suggests that efforts should be made by authorities to promote and valorize the rearing of indigenous pigs in complement to exotic pig breeds in view of strengthening the Cameroonian pig industry.