Growth Medium Research Articles

In Vitro Rooting of <em>Gyrinops walla</em> in Activated Charcoal-Containing Semi-Solid Culture and Filter Paper-Bridged Liquid Culture Systems

Plant tissue culture is the best option in producing planting material for cultivation programmes of Gyrinops walla. Perfection of in vitro rooting protocol for this species is the most decisive step in micropropagation. In the present study the effect of physical state of substrate, different concentrations of sucrose, IBA and NAA in media containing activated charcoal on in vitro rooting was investigated. In experiment-1, 0.2% (w/v) activated charcoal was added in to the ½ MS medium fortified with 30 or 40 g/L sucrose and varying concentrations of IBA or NAA (0, 0.1, 0.5, 1.0 and 2.0 mg/L). In experiment-2, filter paper-bridged liquid medium was used with 40 g/L sugar and varying concentrations of IBA or NAA (0, 0.1, 0.5, 1.0 and 2.0 mg/L). The treatments were arranged in completely randomized design with three replicates. Percentage of rooted microshoots and number of roots per shoot were recorded. The ½ MS semi-solid medium with 0.2% activated charcoal, 40 g/L sucrose and 0.1 mg/L NAA resulted in the significantly highest rooting percentage (50%)while the significantly highest number of roots (6.0) were noted in ½ MS charcoal added (0.2%) basal medium with 40 g/L sucrose and 0.5 mg/L NAA. Shoots supported with filter paper bridge on ½ MS liquid medium, supplemented with 0.5 mg/L IBA, had the highest rooting percentage (66.7%) and the highest mean number of roots per shoot (3.0) (P<0.05). Results confirmed that in vitro rooting of G. walla could be perfected by optimizing the culture medium and its constituents.

Engineering living root with mechanical stimulation derived from reciprocating compression in a double network hydrogel as elastic soil

The root system actively reacts to mechanical stimuli in its environment, transmitting mechanical signals to optimize the utilization of environmental resources. While the mechanical impedance created by the growth medium serves as the primary source of stimulation for the roots, extensive research has focused on the roots' response to static mechanical stimulation. However, the impact of dynamic mechanical stimulation on root phenotype remains underexplored. In this study, we utilized a low acyl gellan gum/polyacrylamide (GG/PAM) double network elastic hydrogel as the growth medium for rapeseed. We constructed a mechanical device to investigate the effects of reciprocating extrusion stimulation on the growth of the rapeseed root system. After three weeks of mechanical stimulation, the root system exhibited a significant increase in lateral roots. This branching enhanced the roots' anchoring and penetration into the hydrogel, thereby improving the root system's adaptability to its environment. Our findings offer valuable data and insights into the effects of reciprocating mechanical stimulation on root growth, providing a new way for engineering root phenotype.

Growth and physiology responses of Samanea saman inoculated with arbuscular mycorrhizal fungi in silica post-mining soil media using biodegradable pots

Arbuscular mycorrhizal fungi (AMF) and biodegradable pots are environmentally friendly and enhance plant growth in adverse soil conditions. These studies explored AMF interactions and biodegradable pots in physiology, growth, and the uptake of nutrients in Samanea saman seedlings. The present research interactive effects of biodegradable pots with different compositions and raw material sizes with and without AMF inoculation on S. saman grown in silica post-mining soil media. Results indicated AMF inoculations significantly improved leaf chlorophyll content, photosynthetic rate, heights, diameters, biomass, as well as nutrient absorption of S. saman as compared with non-inoculated plants in biodegradable pots. AMF and biodegradable pots composed of 15% used newspaper, 70% compost, 5% cocopeat, and 10% rock phosphate showed the best results and increased the leaf chlorophyll content, photosynthesis rate, height, diameter, and total biomass of the plants by 161.1%, 208.7%, 263.6%, 118.1%, and 269.9%, respectively, compared to biodegradable pots composed only of used newspaper. Additionally, uptake of the nutrients nitrogen, phosphate, potassium, and magnesium increased by 365%, 800%, 369%, and 250%, respectively. By the fourteenth week after transplanting, the C/N ratio of the organic pot decreased significantly. Thus, AMF and biodegradable pots containing compost and rock phosphate interact positively and enhance the growth of S. saman under adverse soil conditions. These findings suggest that biodegradable pots containing compost and rock phosphate show potential as more environmentally friendly replacements for plastic bags (polybags) as growth medium containers for seedling production.

Experimental setup for comprehensive study of non-stationary heat transfer in complex liquid media.

This paper presents a setup for studying non-stationary heat exchange in liquid media on a scale of small times and sizes at high heat flux densities created using a high-speed precision power controller. A platinum wire with a diameter of 20μm and a length from 0.5 to 1cm is used as a probe. The heating time ranged from 1 to 300ms, and the heat flux densities from 1 to 20 MW/m2 were achieved in the experiments. Strictly specified conditions for heat release in the probe are confirmed by maintaining a constant power in a series of pulses with an accuracy of 0.05%. Acquiring a primary electrical signal of thermograms is synchronized with high-speed video recording, allowing an accurate relationship between the applied thermal load and the mechanics of processes in the studied liquid. The setup capabilities were shown by comparing the boiling patterns of a simple substance, such as ethanol, and a solution with a lower critical solution temperature, a 30 vol.% solution of polypropylene glycol-425 in water, which have similar thermograms. As a result, a qualitative difference between the heating and boiling patterns observed using high-speed video and the presented setup fitting its purpose has been shown.

Investigation of Antimicrobial Compounds Produced by Endolichenic Fungi in Different Culture Media.

Continuous use of synthetic fungicides has led to explosive emergence of fungicide-resistant microbes. Therefore, there are urgent needs for environmentally friendly antimicrobial agents with novel modes of action. This study investigated endolichenic fungi (ELF) as a source of antimicrobial compounds against various plant pathogens. We utilized an One Strain MAny Compounds (OSMAC) approach to enhance the chemical diversity of fourteen ELF. This involved cultivation of ELF in four growth media and subsequently assessing antimicrobial activities of culture extracts. Nearly half of the culture extracts exhibited antimicrobial activity against a Gram-positive bacterium, but showed minimal activity against Gram-negative bacteria tested. Notably, culture extracts from two ELF, Chaetomium globosum and Nodulisporium sp., demonstrated significant inhibitory effects against plant pathogenic fungi. LC-MS/MS-based metabolome profiling confirmed the presence of known bioactive compounds like cyclic dipeptides and chaetoglobosins. These findings highlight the effectiveness of combining OSMAC and metabolomics for identifying antimicrobial agents for agricultural use.

Biological response guided by hybrid additive manufacturing for Ti6Al4V titanium alloy

This research evaluates the cellular response from Ti6Al4V scaffolds fabricated by hybrid additive manufacturing (AM) with the goal of improving bone tissue growth and biocompatibility of titanium implants. Since cellular adhesion and viability are subject to microstructure, hybrid AM was sought to dictate biological response by creating a dispersed and gradient microstructure within implants. The objective was to evaluate the effect of gradient microstructures within Ti6Al4V scaffolds on cellular metabolic activity. Gradient microstructure was incorporated within scaffolds by hybrid AM coupling directed energy deposition (DED) with interlayer milling. The cellular response from the scaffolds was evaluated using cell viability assays in two stages: the Ti6Al4V powder used for DED was first evaluated, followed by the fabricated scaffolds. Cell viability on hybrid AM scaffolds was compared with as–printed, i.e., DED-fabricated and annealed Ti6Al4V scaffolds. The cell viability assays demonstrated that Ti6Al4V powder was non-toxic as cells cultured with powder exhibited metabolic activity similar to cells in growth media without powder. The cell viability study on scaffolds indicated, on average, cell adhesion on hybrid AM scaffolds outperformed as–printed and annealed scaffolds. This study provides preliminary data demonstrating the use of hybrid AM to dictate cell activity. A larger sample set would be required in future work to understand the effects of grain refinement through coldworking on biological response.

3D bioprinting meniscus tissue onboard the International Space Station

We bioprinted meniscus tissue on the International Space Station (ISS) using the onboard BioFabrication Facility (BFF). The three dimensional (3D) printing bioink, cells, culture media and fixative were delivered to the ISS on NG-18 and SpX-27 vehicles and stored prior to the printing operation. The meniscus tissue was fabricated from ink composed of collagens type I and II, chondroitin sulfate and mesenchymal stem cells. Following printing, the meniscus tissue was cultured for 2 weeks in growth media, then stored at 4 °C and returned to earth for analysis. The print showed good overall shape fidelity, and dimensions were comparable to control meniscus tissue printed on Earth. Young's modulus of the ISS printed meniscus was approximately 4-fold lower than the control. Histologic evaluation showed good cell distribution within the print. Though logistical challenges were encountered during payload delivery to the ISS and operational challenges limited the cell culture portion of this study, this investigation demonstrated the feasibility for 3D printed musculoskeletal tissue in microgravity. The completed meniscus tissue print is the largest tissue engineered model 3D printed on the ISS to date, the first to be 3D bioprinted using an ink similar in composition to native tissue, and the first to be fabricated on the ISS in an anatomically relevant shape. These experiments help advance the field of tissue engineering in low or microgravity where 3D bioprinting may have a role in future long term space flight or extraterrestrial habitation.

Dismantling of Necrotroph Alternaria alternata by Cellular Intervention of Peppermint oil Nanoemulsion (PNE).

Alternaria alternata, a common necrotrophic fungal pathogen, poses a significant threat to various crops, causing substantial yield losses and quality deterioration. In the present study, we explore the potential fungicidal properties of Peppermint Oil Nanoemulsion (PNE) against A. alternata and investigate its impact on the fungal phenotype. Our previous study synthesized the PNE using a nanoemulsion approach, optimizing its formulation for enhanced stability and efficacy. The present study extended the assessment of a multidisciplinary approach to comprehensively analyze the fungicidal efficacy of PNE against A. alternata. Notably, in a liquid growth medium, 0.5% of PNE could reduce A. alternata's biomass by 96%. PNE-treated mycelia were stained with a nitro-blue tetrazolium (NBT) dye to assess ROS accumulation during oxidative stress induced by PNE. A higher degree of ROS generative potential of PNE has appeared in 72 h treated mycelia. PNE-treated mycelium showed cell wall alterations, with red fluorescence peaking at 0.5%, indicating a dose-dependent effect compared to the untreated control. Consequently, PNE treatment led to a significant early hour increase in electrical conductivity (EC), extended to 306.03-353.33 μS/cm compared to 277.67-280.33 μS/cm untreated control. Scanning Electron Microscopy (SEM) analysis of A. alternata reflects the osmotic imbalance and structural damage in mycelia as the obvious cause of fungal inhibition. In addition, a phenotype microarray analysis of PNE-treated A. alternata mycelia revealed a significant phenotypic loss in 37 out of 708 substrates, potentially impacting metabolic pathways essential for fungi's functional processes. The study found that downregulation of genes like Cre A, NmrA, SOD, IMP, EfP, and Erg, which are linked to A. alternata's stress coping mechanisms, leads to alterations in survival and adaptation. Additionally, understanding the phenotypic changes induced by PNE contributes to our knowledge of the mode of action of this nanoemulsion against A. alternata. In conclusion, this study provides a comprehensive analysis of the fungicidal and phenotypic effects of PNE, offering a promising avenue for sustainable fungal control. The implications of our research extend to the development of novel, natural fungicidal agents for agricultural applications.

Enhancing Resistance to Corrosion and Fouling Using Epoxy Coatings with Superhydrophobic Cells

AbstractAs maritime transport becomes increasingly important, metal corrosion results in significant economic losses. Superhydrophobic materials have significant potential for corrosion prevention. However, poor compatibility between superhydrophobic materials and resin reduces the long‐term corrosion resistance. Interfacial strengthening cells (IS‐Cells) are designed to maintain superhydrophobicity and retain active hydroxyl groups participating in resin‐curing. IS‐Cells also contribute to achieving the maze effect. A novel anti‐corrosion IS coating is fabricated by compatible IS‐Cells and epoxy. IS coatings feature smooth surfaces and vertical compactness, protecting against liquid and gaseous corrosive medium. Strong diffusion resistance and extended diffusion distance ensure long‐term corrosion resistance of IS coatings. Approximately 85 µm of IS coatings remain corrosion‐free after 112 days of immersion in the NaCl solution. The low‐frequency impedance, self‐corrosion potential, and self‐corrosion current density are 1.68 × 109 Ω cm2, −0.0708 V, and 5.38 × 10−11 A cm−2, respectively. IS coatings can also withstand 2400 h of neutral salt spray testing without corrosion in the artificial scratches. Due to the electrostatic repulsion between the hydrophobic C–F chains onto IS‐Cells and protein molecules, IS coatings maintain anti‐fouling properties after dry‐wet immersion tests in the natural marine environment for 90 days. IS coatings show great potential for marine anti‐corrosion applications.

Low Toxicity of Dissolved Silver from Silver-coated Titanium Dental Implants to Human Primary Osteoblast Cells

Objectivesthe controlled release of silver as a biocide from Ag-coated medical implants is desirable. However, the biocompatibility of Ag leachates is poorly understood. This study investigated the toxicity of silver released from the silver plated titanium implants to human primary osteoblast cells; and the effect of cell culture medium on the silver speciation and bioavailability. Methods: Ti6Al4V discs were coated with Ag nanoparticles (NPs), silver plus hydroxyapatite (HA) nanoparticles (Ag+nHA), or Ag NPs plus microparticles (Ag+mHA). Primary human osteoblast cells were exposed to the leachates from the various discs for up to 7 days. Results: the total Ag concentrations released as leachate from the silver-plated titanium discs were 0.7-1.6mgL-1, regardless of treatment. Cumulative silver release over 7 days was approximately 3mgL-1 in all treatments. The concentration of total Ag in the cell homogenates from all the Ag-containing treatments was modest, ~ 0.1µgmg protein-1 or less at day 7. Cells showed normal healthy morphology with no appreciable leak of LDH or ALP activity into the external media compared to the reference control. Similarly, there was no significant differences (Kruskal Wallis, p > 0.05) in the LDH or ALP activity in the cell homogenate between treatments. Conclusions: overall, there was a controlled release of Ag into the external media, but this remained biocompatible with no deleterious effects on the osteoblast cells, which means that the released silver to the peri-implant environment is not toxic making the coating potential for clinical use

Shattering the Water Window: Comprehensive Mapping of Faradaic Reactions on Bioelectronics Electrodes.

It is generally accepted that for safe use of neural interface electrodes, irreversible faradaic reactions should be avoided in favor of capacitive charge injection. However, in some cases, faradaic reactions can be desirable for controlling specific (electro)physiological outcomes or for biosensing purposes. This study aims to systematically map the basic faradaic reactions occurring at bioelectronic electrode interfaces. We analyze archetypical platinum-iridium (PtIr), the most commonly used electrode material in biomedical implants. By providing a detailed guide to these reactions and the factors that influence them, we offer a valuable resource for researchers seeking to suppress or exploit faradaic reactions in various electrode materials. We employed a combination of electrochemical techniques and direct quantification methods, including amperometric, potentiometric, and spectrophotometric assays, to measure O2, H2, pH, H2O2, Cl2/OCl-, and soluble platinum and iridium ions. We compared phosphate-buffered saline (PBS) with an unbuffered electrolyte and complex cell culture media containing proteins. Our results reveal that the "water window"─the potential range without significant water electrolysis─varies depending on the electrolyte used. In the culture medium that is rich with redox-active species, a window of potentials where no faradaic process occurs essentially does not exist. Under cathodic polarizations, significant pH increases (alkalization) were observed, while anodic water splitting competes with other processes in media, preventing prevalent acidification. We quantified the oxygen reduction reaction and accumulation of H2O2 as a byproduct. PtIr efficiently deoxygenates the electrolyte under low cathodic polarizations, generating local hypoxia. Under anodic polarizations, chloride oxidation competes with oxygen evolution, producing relatively high and cytotoxic concentrations of hypochlorite (OCl-) under certain conditions. These oxidative processes occur alongside PtIr dissolution through the formation of soluble salts. Our findings indicate that the conventional understanding of the water window is an oversimplification. Important faradaic reactions, such as oxygen reduction and chloride oxidation, occur within or near the edges of the water window. Furthermore, the definition of the water window significantly depends on the electrolyte composition, with PBS yielding different results compared with culture media.

Endoplasmic reticulum stress alters myelin associated protein expression and extracellular vesicle composition in human oligodendrocytes.

Myelination of the central nervous system is mediated by specialized glial cells called oligodendrocytes (OLs). Multiple sclerosis (MS) is characterized by loss of myelination and subsequent clinical symptoms that can severely impact the quality of life and mobility of those affected by the disease. The major protein components of myelin sheaths are synthesized in the endoplasmic reticulum (ER), and ER stress has been observed in patients with MS. Extracellular vesicles (EVs) have been shown to carry bioactive cargo and have the potential to be utilized as noninvasive biomarkers for various diseases. In the current study, we sought to determine how ER stress in OLs affected the production of key myelination proteins and EV release and composition. To achieve this, tunicamycin was used to induce ER stress in a human oligodendroglioma cell line and changes in myelination protein expression and markers of autophagy were assessed. EVs were also separated from the conditioned cell culture media through size exclusion chromatography and characterized. Significant reductions in the expression of myelination proteins and alterations to autophagosome formation were observed in cells undergoing ER stress. EVs released from these cells were slightly smaller relative to controls, and had strong expression of LC3B. We also observed significant upregulation of miR-29a-3p in ER stress EVs when compared to controls. Taken together, these data suggest that ER stress negatively impacts production of key myelination proteins and induces cells to release EVs that may function to preemptively activate autophagic pathways in neighboring cells.

Biodegradation of imidacloprid and diuron by Simplicillium sp. QHSH-33

Imidacloprid (IMI) and diuron (DIU) are widely used pesticides in agricultural production. However, their excessive use and high residues have caused harm to the ecological environment and human health. Microbial remediation as an efficient and low-toxic method has become a research hotspot for controlling environmental pollutants. A fungus QHSH-33, identified as Simplicillium sp., has the ability to degrade neonicotinoids IMI and phenylurea DIU. When QHSH-33 and pesticide were co-cultured in liquid medium for 7 days, the degradation rates of IMI and DIU by QHSH-33 in simulated field soil microenvironment were 50.19 % and 70.57 %, respectively. Through HPLC-MS analysis, it was found that the degradation of IMI mainly involved nitro reduction, hydroxylation and other reactions. Three degradation pathways and eight degradation products were identified, among which two metabolites were obtained by microbial transformation of IMI for the first time. The degradation of DIU mainly involved demethylation and dehalogenation reactions, and two degradation pathways and four degradation products were identified, one of which was a new degradation product of DIU. Toxicity assessment demonstrated that most of the degradation products might be considerably less harmful than IMI and DIU. Whole genome sequencing of QHSH-33 revealed a genome size of 33.2 Mbp with 11,707 genes. The genome of QHSH-33 was annotated by KEGG to reveal 128 genes related to exogenous degradation and metabolism. After local blast with reported IMI and DIU degrading enzymes, seven IMI-degrading related genes and seven DIU-degrading related genes were identified in the QHSH-33 genome. The results of this study will help to expand our knowledge on the microbial decomposition metabolism of IMI and DIU, and provide new insights into the degradation mechanism of IMI and DIU in soil and pure culture system, laying a foundation for QHSH-33 strain applied to the removal, biotransformation or detoxification of IMI and DIU.

Decellularized extracellular matrix derived from dental pulp stem cells promotes gingival fibroblast adhesion and migration

BackgroundDecellularized extracellular matrix (dECM) has been proposed as a useful source of biomimetic materials for regenerative medicine due to its biological properties that regulate cell behaviors. The present study aimed to investigate the influence of decellularized ECM derived from dental pulp stem cells (DPSCs) on gingival fibroblast (GF) cell behaviors. Cells were isolated from dental pulp and gingival tissues. ECM was derived from culturing dental pulp stem cells in growth medium supplemented with ascorbic acid. A bioinformatic database of the extracellular matrix was constructed using Metascape. GFs were reseeded onto dECM, and their adhesion, spreading, and organization were subsequently observed. The migration ability of the cells was determined using a scratch assay. Protein expression was evaluated using immunofluorescence staining.ResultsType 1 collagen and fibronectin were detected on the ECM and dECM derived from DPSCs. Negative phalloidin and nuclei were noted in the dECM. The proteomic database revealed enrichment of several proteins involved in ECM organization, ECM–receptor interaction, and focal adhesion. Compared with those on the controls, the GFs on the dECM exhibited more organized stress fibers. Furthermore, cultured GFs on dECM exhibited significantly enhanced migration and proliferation abilities. Interestingly, GFs seeded on dECM showed upregulation of FN1, ITGB3, and CTNNB1 mRNA levels.ConclusionsECM derived from DSPCs generates a crucial microenvironment for regulating GF adhesion, migration and proliferation. Therefore, decellularized ECM from DPSCs could serve as a matrix for oral tissue repair.

Single-cell phenotypic profiling and backtracing exposes and predicts clinically relevant subpopulations in isogenic Staphylococcus aureus communities

Isogenic bacterial cell populations are phenotypically heterogenous and may include subpopulations of antibiotic tolerant or heteroresistant cells. The reversibility of these phenotypes and lack of biomarkers to differentiate functionally different, but morphologically identical cells is a challenge for research and clinical detection. To overcome this, we present ´Cellular Phenotypic Profiling and backTracing (CPPT)´, a fluorescence-activated cell sorting platform that uses fluorescent probes to visualize and quantify cellular traits and connects this phenotypic profile with a cell´s experimentally determined fate in single cell-derived growth and antibiotic susceptibility analysis. By applying CPPT on Staphylococcus aureus we phenotypically characterized dormant cells, exposed bimodal growth patterns in colony-derived cells and revealed different culturability of single cells on solid compared to liquid media. We demonstrate that a fluorescent vancomycin conjugate marks cellular subpopulations of vancomycin-intermediate S. aureus with increased likelihood to survive antibiotic exposure, showcasing the value of CPPT for discovery of clinically relevant biomarkers.

Suitability of Phytoremediation Processes for Indoor Air and Practical Applications

Background: It is more challenging than designing buildings, people have difficulty improving indoor air quality (IAQ) affordably in existing buildings with limited area. This paper presents indoor phytoremediation solutions-based quotations, which are affordable to the public, besides being able to work to remediate air simultaneously. Methods: Literature sources are primarily Mendeley reference managers and expanded from open-access reputable journals worldwide. The indoor phytoremediation solution was obtained from an up-to-date literature review covering processes of all plants and related sections. Results: The study identified three categories of indoor phytoremediation: plant-related bioremediation, rhizosphere bioremediation, and plant processes. To improve indoor air quality, plant-related bioremediation is a suitable process to escalate while still paying attention to ameliorating the plant processes and inhibiting bioaerosols. For practical applications, narrow-leaved plant species can enhance phylloremediation, growth media amendments to enhance rhizosphere bioremediation, and support separating biodegradable waste. Placing one decorative plant anywhere indefinitely improves the IAQ for buildings with a limited area because plants are essential biota of a living ecosystem. Conclusion: Based on the suitability of the process for indoor air pollutants, the main contribution of plants to remediate indoor air is plant-related bioremediation, followed by plant processes, and rhizosphere bioremediation

Pretreated sugarcane bagasse matches performance of synthetic media for lipid production with Yarrowia lipolytica

Engineered strains of Yarrowia lipolytica with modified lipid profiles and other desirable properties for microbial oil production are widely reported but are almost exclusively characterized in synthetic laboratory-grade media. Ensuring translatable performance between synthetic media and industrially scalable lignocellulosic feedstocks is a critical challenge. Yarrowia lipolytica growth and lipid production were characterized in media derived from two-step acid-catalyzed glycerol pretreatment of sugarcane bagasse. Fermentation performance was benchmarked against laboratory-grade synthetic growth media, including detailed characterization of media composition, nitrogen utilization, biomass and lipid production, and fatty acid product profile. A Yarrowia lipolytica strain modified to enable xylose consumption consumed all sugars, glycerol, and acetic acid, accumulating lipids to 34–44 % of cell dry weight. Growth and lipid content when grown in sugarcane bagasse-derived media were equivalent to or better than that observed with synthetic media. These sugarcane bagasse-derived media are suitable for transferable development of Yarrowia lipolytica fermentations from synthetic media.

Physico-chemical characteristics of melanins culture medium Inocutis dryophila (Berk) Flasson & Niemela

The purpose of the study was to investigate the effect of light treatment on the synthesis of endomelanins from the mycelium of Inocutis dryophila in a liquid culture medium. To identify the effect of light on the synthesis of melanins, the mycelium of Inocutis dryophila was cultivated in a liquid medium in the dark and using blue light treatment. As a result, two types of melanins IDM-1 and IDM-2 were obtained. It has been established that the light factor influences the quantitative release of melanins from the mycelium of Inocutis dryophila into the culture liquid. The use of blue light resulted in lower melanin content in the culture fluid than in the dark. Ultraviolet and infrared spectrometry showed that both types of melanins have typical spectra and graphs for fungal melanins. Infrared spectrometry showed that treatment of mycelium with blue light led to deformation of IDM-1. It was revealed that IDM-2 melanins exhibit greater antiradical activity than IDM-1 melanins. Thus, light treatment of Inocutis dryophila mycelium in a liquid medium affects the quantitative release of melanins into the culture liquid, promotes a change in the structure, as well as manifestation of a biological effect.

Photoluminescent carbon colloids prepared by laser fragmentation of carbon from waste coffee grounds

Colloidal suspensions of carbon nanostructures (CNSs) were prepared by laser fragmentation in various liquid media using heat-treated coffee grounds as carbon precursor. A study by calorimetry was done in powder of waste coffee grounds to determine the temperature of obtaining carbon. The experiments were carried out in two stages, the first one consisted in obtaining the carbon source, for which powder of waste coffee grounds was thermally treated in air. The as-obtained carbon was characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, Raman spectroscopy and infrared spectroscopy. In the second step the as-obtained carbon was separately dispersed in four liquid media (acetone, toluene, methanol and isopropyl alcohol) to be fragmented by using a ns-pulsed Nd:YAG laser at its 1064 nm fundamental emission. The morphological features of the carbon nanostructures were obtained by transmission electron microscopy, while the optical properties of the colloidal suspensions were characterized by UV-Vis and photoluminescence spectroscopies. Results indicate that carbon nanostructures are successfully obtained in the four liquid media after the fragmentation process. The four colloidal suspensions show photoluminescent properties, which are seen to depend on the liquid medium nature. We found that the liquid medium also influences the efficiency of the laser fragmentation.

Absorbance measurement for interdisciplinary educational experiment on cytotoxicity

Abstract We propose a multidisciplinary educational experiment, linking knowledge and skills in physics, biology and information technology through the training and application of the research method by students. From a physics point of view, the experiment consists in light absorption measurement, and in terms of biology, it demonstrates the process of cytotoxicity evaluation by means of the colorimetric method neutral red uptake in vitro test. The test allows to determine the concentration of a test drug at which 50% cytotoxicity (CC50 values) of the cells is observed. After initial exposure to the tested drug, neutral red (NR) is added to the cell culture medium, it is absorbed by the living cells and subsequently released in a desorb buffer. The cell culture medium becomes coloured, and the more intensive colour corresponds to higher cell viability, while more transparent solution corresponds to lower number of living cells. The NR concentration in the solution is estimated by the absorbance value. We measure the absorbance of NR by utilizing a very affordable educational-grade spectrometer and compare its output with that of a professional microplate reader. We show that the educational spectrometer gives a result on the CC50 value that is in agreement with the acceptable values of the official protocol. We include a comment on the results when performing this laboratory exercise in one class of 18 year old students (in their last year of secondary education). The experiment can be also successfully applied in the laboratory practicum of first year university study.