Solution Culture Research Articles

Effect of environmental factors on expression of staphylococcal enterotoxin genes.

Staphylococcal enterotoxins (SEs) secreted by Staphylococcus aureus (S. aureus) can cause foodborne disease, nausea, vomiting and diarrhea, and even death. Regulation of SE expression is related to accessory gene regulators (Agr). It is important to reveal which environmental factors influence regulation of SE expression to prevent SE food poisoning outbreak. Hence, natural environmental factors which may have an impact on SE expression were selected, such as temperature, food types, strains, and competing strains. Seven strains of S. aureus carrying different SE genes were collected from the Chinese Academy of Inspection and Quarantine (CAIQ) strain bank for study. Strains were cultured with different conditions. Temperature was 8°C, 22°C, and 30°C. Food type was milk powder and nutrient broth. Competing strains were Vibrio parahaemolyticus (V. parahaemolyticus), Escherichia coli (E. coli), and Bacillus cereus (B. cereus). The expression culture solution was pretreated by centrifugation, then determined by using SDS-PAGE, and distinguished SEs apart from each other by HPLC-ESI-TOF. There are 168 samples collected from SE expression culture; the result of SDS-PAGE suggests 23 samples were positive for SEs, and the other 145 samples were negative for SEs. The result of HPLC-ESI-TOF suggests that SEs with similar molecular weight can be distinguished in terms of m/z. The most important factor contributing to regulate expression of SEs was estimated by logistic regressive analysis. The result shows that McFadden R2 is 0.213; p value is 0.000 (p < 0.05); this result illustrates that the model is valid and meaningful. Strains, food types, temperature, and competing strands can explain the 21% change in SE expression. Temperature (z = 3.029, p = 0.002 < 0.01), strains (z = - 3.132, p = 0.002 < 0.01), and food types (z = - 2.415, p = 0.016 < 0.05) have significant impact on SE expression, and the competing strains (z = 1.230, p = 0.219 > 0.05) have no impact on the SE expression. More important impact on SE expression was estimated by OR value; the result shows that strength of temperature influencing on SE expression is bigger than strains and food types in terms of values of OR, temperature (OR = 2.862), strains (OR = 0.641), and food types (OR = 0.561); consequently, temperature is a key factor for stimulating SE expression and had high expression at 30°C. Therefore, food easily contaminated with S. aureus should be monitored intensively at early and late summer, when proper temperature for expressing SEs may result in S. aureus food poisoning prevalence.

Investigating the Combined Effects of Mechanical Stress and Nutrition on Muscle Hypertrophic Signals Using Contractile 3D-Engineered Muscle (3D-EM).

Since 3D-EM closely resembles in vivo muscles, the aim of this study was to investigate the effects of exercise (electrical pulse stimulation (EPS)) and nutrition (maca), which contains triterpenes, on muscle hypertrophy by using 3D-EM for the first time. The 3D-EM was composed of C2C12 cells and type 1 collagen gel, was differentiated for 14 days, and was divided into four groups: control, maca, EPS, and maca + EPS. The medium was replaced every two days before each EPS intervention, and the concentration of maca in the culture solution was 1 mg/mL. The intervention conditions of the EPS were 30 V, 1 Hz, and 2 ms (24 h on, 24 h off, for one week). The expression levels of proteins were examined by Western blotting. The intervention of maca and EPS upregulated the expression of MHC-fast/slow (both p < 0.05) compared with the control group, and the addition of maca had no effect on the phosphorylation of mTOR (p = 0.287) but increased the AMPK phosphorylation (p = 0.001). These findings suggest that intervention with maca and EPS has a positive effect on muscle hypertrophy, which has a positive impact on sarcopenia. However, the underlying mechanisms remain to be further explored.

Role of culture solution pH in balancing CO2 input and light intensity for maximising microalgae growth rate

The interplay between CO2 input and light intensity is investigated to provide new insight to optimise microalgae growth rate in photobioreactors for environmental remediation, carbon capture, and biomass production. Little is known about the combined effect of carbon metabolism and light intensity on microalgae growth. In this study, carbonated water was transferred to the microalgae culture at different rates and under different light intensities for observing the carbon composition and growth rate. Results from this study reveal opposing effects from CO2 input and light intensity on the culture solution pH and ultimately microalgae growth rate. Excessive CO2 concentration can inhibit microalgae growth due to acidification caused by CO2 dissolution. While increasing light intensity can increase pH because the carboxylation process consumes photons and transfers hydrogen ions into the cell. This reaction is catalysed by the enzyme RuBisCO, which functions optimally within a specific pH range. By balancing CO2 input and light intensity, high microalgae growth rate and carbon capture could be achieved. Under the intermittent CO2 transfer mode, at the optimal condition of 850 mg/L CO2 input and 1089 μmol/m2/s light intensity, leading to the highest microalgae growth rate and carbon fixation of 4.2 g/L as observed in this study.

Barium Promoted Seed Germination and Seedling Growth of Higher Plants in Solution Culture

The effects of various concentrations of barium (Ba) on seed germination and early seedling growth of wheat and mung bean were studied. Ba influenced the seedling growth of wheat and mung bean in similar fashion. Ba enhanced the germination relative index at lower concentration (upto 10 μg ml-1). The relative yield of biomass increased at lower doses of Ba and decreased at higher concentration (&gt;100 μg ml-1). Lower applied doses of Ba showed a maximum index of tolerance while higher applied doses of metal showed a toxic effect on plant growth. The toxic effect of barium on mung bean was more marked than on wheat.

Differential interference of copper with endophytic bacterial inoculation: Atrazine decontamination in Acorus tatarinowii and culture solution

To clarify the interference effects of inorganic ions, Acorus tatarinowii and endophytic bacterium Herbaspirillum huttiense (Hh) were combined to decontaminate atrazine pollution under different copper levels. This study verified inoculation effects and revealed the complicated processes of atrazine transformation in solutions. 35.9% leaf biomass was promoted by Hh inoculation, and the value was lowered to 7.87% by high doses of copper. The changing trend of leaf N, K, and S contents, and tiller numbers were consistent with that of leaf biomass. Hh injection improved atrazine accumulation by 43.5% in roots, and under copper interference, this value lowered to 10.6%. Hh promoted atrazine deethylation in plants, which was copper-dose dependent in different plant organs. In solutions, atrazine was conjugated with small-molecule secretions at m/z 118, detoxicated into 2-hxydroatrazine and 2-hydroxy-4-acetamido-atrazine, then the triazine ring opened. Copper interference had a more significant impact on residual atrazine conversion products than Hh inoculation treatments. Hh treatment promoted the ring-opening degradation of atrazine in water. The addition of high doses of copper ions promoted the oxidative process of atrazine while inhibiting its ring-opening transformation process in water.

Ecological toxicity of microplastics, aluminum and their combination to ectomycorrhizal fungi (Lactarius delicious)

&lt;p&gt;To investigate the combined toxic effects of microplastics and aluminum (Al) on ectomycorrhizal fungi, Lactobacillus delicious (Ld) was selected as the experimental subject to conduct research on monodisperse polystyrene microplastics (PS-MPs) (0, 20, 100, 200 mg L-1) and Al3+ (40 mg L-1) single pollution on Ld growth, the antioxidant system and organic acid secretion, followed by their combined effect. The results showed that the growth of Ld was inhibited and the biomass decreased significantly (P &amp;lt; 0.05) under single exposure to PS-MPs or Al3+, and the contents of superoxide anion radical (O2·-) and H2O2 in mycelia increased significantly (P &amp;lt; 0.05). Meanwhile, superoxide dismutase (SOD) and peroxidase (POD) activities were also significantly increased (P &amp;lt; 0.05), while catalase (CAT) activity was significantly decreased (P &amp;lt; 0.05), indicating that PS-MPs or Al3+ stress had different effects on antioxidant enzyme activities in Ld mycelia, which used highly active antioxidant enzymes to eliminate excess reactive oxygen species (ROS) and maintain their dynamic balance. In addition, the electrolyte leakage rate, proline and malondialdehyde (MDA) contents in Ld mycelia were significantly increased (P &amp;lt; 0.05). Under the combined exposure of PS-MPs and Al3+, compared with the control group, the combined exposure of high concentrations of PS-MPs and Al3+ (200+40 mg L-1) had a certain promoting effect on the biomass of Ld. In addition, the O2·-, H2O2, electrolyte leakage rate and malondialdehyde content in Ld mycelia increased significantly (P &amp;lt; 0.05), but these indices were significantly lower than those in the single PS-MPs exposure group at the same concentration. This indicates that the combined effect of PS-MPs and Al3+ could reduce the damage of single pollutants to the Ld biomass membrane and reduce the production of ROS to a certain extent. In addition, correlation analysis showed that H2O2 in Ld mycelia had a highly significant positive correlation with the oxalic acid and total hydrogen ion concentrations in the culture solution (P &amp;lt; 0.01). This indicates that strain Ld could respond to the oxidative damage caused by microplastics and Al by secreting oxalic acid and hydrogen ions into the culture medium.&lt;/p&gt;&#x0D;

Potential use of Rorippa sylvestris (L.) Besser. as a cadmium hyperaccumulator for phytoremediation

Rorippa sylvestris (L.) Besser. (yellow fieldcress) is a hyperaccumulator of cadmium (Cd) discovered recently. There are several studies in the topic of Cd tolerance capacity and detoxification mechanism of plants, but the detoxification mechanism of R. sylvestris is not clear. Root tiller seedlings of R. sylvestris were planted in the brown bottles filled with culture solution containing different levels of Cd (0, 10, 25, 50, 100, 200 μmol·L−1, respectively) for 8 days in order to make sure the physiological responses, Cd subcellular distribution and chemical forms under Cd stress. The results showed that the growth increased in lower Cd concentration and declined in higher Cd concentration. Physiological characteristics such as photosynthesis and MDA were not significantly affected compared with the control at Cd concentratetion ≤ 50 μmol·L−1. The content of soluble sugar and free proline increased with the increasing of Cd concentration for the purpose of reducing the Cd toxicity to plant. R. sylvestris had a strong capability of Cd accumulation in different Cd treatments. The concentration of Cd in plant tissues (root, stem, leaf) was in the order of root>stem>leaf. The Cd subcellular distribution in plant tissues of R. sylvestris was in the order of soluble fractions>cell wall>protoplast>mitochondria. Cd was mainly extracted by deionized water and 80% ethanol (60.91–69.76%), followed by sodium chloride (16.14–25.12%), which indicated that R. sylvestris achieved to enhance Cd tolerance capacity and detoxification mechanism through root retention and vacuolar compartmentalization.

Sensitivity of capsicum germplasm to magnesium deficiency growing in the solution culture

Sensitivity of capsicum germplasm to magnesium deficiency growing in the solution culture

Yeast suppresses Aspergillus parasiticus growth and aflatoxins synthesis: Finding a new fungal antagonistic strain based on stored marinade

Aspergillus parasiticus is prone to producing toxic and carcinogenic aflatoxins (AFs) and posing risks to food safety. This study aims to explore the effect of yeasts isolated from marinade on the growth of A. parasiticus and to evaluate the inhibitory effects of these yeasts on the biosynthesis of AFs and their ability to remove AFs. Six yeast strains were screened through 18S rDNA and ITS rDNA gene sequence analysis, and among them, Candida tropicalis, Pichia kudriavzevii, Trichosporon asahii, Lodderomyces elongisporus and Pichia fermentans showed vigorous growth activity in the stored marinade. P. fermentans and L. elongisporus culture solutions significantly inhibited the growth and mycelial differentiation of A. parasiticus and effectively removed AFB1. The volatile compounds of P. fermentans and L. elongisporus significantly inhibited the growth of A. parasiticus, with inhibition rates of 72.10% and 67.03%, respectively. In addition, P. fermentans and L. elongisporus were co-cultured with A. parasiticus in marinade for seven days. The inhibition rates of AFB1 synthesis were 69.06% and 61.78%, while the inhibition rates of AFG1 were 65.89% and 60.02%, respectively. Hence, P. fermentans and L. elongisporus can be used as fungal antagonistic strains to help reduce AFs contamination in the marinade and its products.

Sensitive detection of heavy metal stress in aquatic plants by dissolved oxygen-quenched fluorescence/materials movement-induced beam deflection method.

Sensitive detection of heavy metal (HM) stress in aquatic plants by dissolved oxygen (DO)-quenched fluorescence/materials movement-induced beam deflection method is demonstrated. Egeria densa Planchon and Cu2+ were used as a model aquatic plant and HM ion, respectively. Reproducibility and experimental errors of the method were first investigated in a control culture solution only containing 10-6M Ru (II) complex (Tris (2,2'-bipyridyl) ruthenium (II) chloride) without addition of any fertilizer and Cu2+. Changes of DO concentration (∆DO) and deflection (∆DE) during the monitoring periods were used as parameters to quantitatively evaluate the experimental errors and detection limits. Averages or means ([Formula: see text], [Formula: see text]) and standard deviations (σ∆DO, σ∆DE) of ∆DO and ∆DE in seven control experiments with different aquatic plants sheets during both the respiration and photosynthesis processes were obtained. Next, DO and deflection at the middle vicinities of the aquatic plant were monitored during 2h of both respiration and photosynthesis in presence of 10-10 ~ 10-6M Cu2+. Experimental results showed that the aquatic plant began to suffer from the HM stress in some extent in presence of 10-9M Cu2+. When the concentration of Cu2+ was higher than 10-8M, changing trends of both DO and deflection with time were not reversed during the respiration and photosynthesis, implying that the materials movements in the physiological activities had been altered greatly. It is demonstrated that the method could sensitively detect the HM stress in the aquatic plants given by nM HM ions in culture solution without addition of a fertilizer. Furthermore, detection limits of the method were quantitatively discussed by considering [Formula: see text] σ∆DO and [Formula: see text] σ∆DE as the minimum detectable changes of DO and deflection caused by the HM stress, respectively.

Aggregation of Thermoresponsive Polymethacrylates in a Dulbecco's Modified Eagle Medium and Its Salts.

The thermal behavior and aggregation process of the poly(N-isopropyl acrylamide), poly[oligo(ethylene glycol) methyl ether methacrylate], and poly[(2-hydroxyethyl methacrylate)-co-oligo(ethylene glycol) methyl ether methacrylate] thermoresponsive polymers were studied in a commonly used Dulbecco's Modified Eagle Medium (DMEM) cell culture medium and solutions of its individual components in the same concentration as found in DMEM. All studied copolymers exhibited an unexpected transmittance profile in the DMEM. During heating above the cloud point temperature (TCP), the polymers additionally aggregated, which led to the formation of their precipitates. The behavior of the polymers was further studied to evaluate how individual salts affected the transition temperature, size (Dh), and stability of the polymer particles. Organic additives, such as amino acids and glucose, had a significantly lesser impact on the thermoresponsive aggregation of the polymers than inorganic ones. Changes to the TCP were small and the formation of precipitates was not observed. The presence of small amounts of amino acids caused a decrease in the polymer aggregate sizes. Obtained results are of utmost importance in thermoresponsive drug nanocarrier studies.

Morphological traits and Zn content of several cassava genotypes in nutrient solution culture

Leaf morphological characters and nutrient content in leaf tissue can vary depending on plant genotype. The nutrient solution culture can produce leaves with good nutritional content. Therefore, this research aimed to evaluate and validate cassava putative mutants' morphological traits and Zn content using a nutrient solution culture system. This research was carried out from January to May 2022 at the greenhouse of Cikabayan Experimental Garden, IPB University, Bogor. This study used two cassava cultivars and ten mutant genotypes from the cassava research team of IPB University, resulting from mutation breeding by gamma irradiation. The plant characters observed in this study included the number of leaves, length and width of the leaflet, leaf colour, plant height, fresh and dry weight leaf, and analysis of Zn content. The data were analyzed using ANOVA at a significant level of α = 5%, followed by Tukey's further test. The results showed that the G2D1-422 genotype had a higher Zn content than the wild type (Ratim/G2) and the other genotypes. The high Zn genotypes (G2D1-422) and low Zn genotypes (Ratim (G2) had not significantly different in fresh and dry leaf weight. Meanwhile, the plant genotype did not affect other growth characteristics such as plant height, the number of leaves, and the length and width of the leaflets, and overall, the characters were similar between the observed genotypes.

Efficient magnetic flocculation for microalgae harvesting using a novel composite flocculant of Fe3O4-based starch-grafted-cationic polyacrylamide

As a flocculant for algae harvesting, a novel magnetic starch-grafted-cationic polyacrylamide composite (MAG@ST-g-CPAM) was developed in this study, and the harvesting efficiency of the composite was assessed with comparison to starch, Fe3O4 magnetite nanoparticles, cationic polyacrylamide and starch-grafted-cationic polyacrylamide. The feeding ratios for flocculant synthesis were optimized, and impacting factors were examined. Magnetic particles were recovered for cyclic use, and the effect of MAG@ST-g-CPAM flocculation on water reuse was examined. The results showed that MAG@ST-g-CPAM flocculation successfully achieved harvesting efficiencies of 93.2 % and 97.3 % at doses of 25 mg/L and 30 mg/L, respectively, which were superior to those of other flocculants. The optimized feeding ratio of acrylamide:Fe3O4:starch was 6:4:3. The late exponential algal growth solution with a pH range of 5–6 was most favorable for algae flocculation. A total of 93.7 % of Fe3O4 magnetite nanoparticles was recovered at pH = 3, and flocculation facilitated the reuse of water by effectively eliminating fulvic acids from the culture solution. This study demonstrated that MAG@ST-g-CPAM is a promising flocculant for algae harvesting.

Effect of heavy metals in aquaculture water on the growth of microalgae and their migration mechanism in algae-shellfish system

This research the bait microalgae Chlorella sp. and Isochrysis zhangjiangensis were fed to Ruditapes philippinarum (clams) using two types of cultures, monoculture and co-culture, simulating the conditions, and presence, of common heavy metals Cu2+, Pb2+ and Cd2+ in cultured waters. The effects of microalgae growth, antioxidant activity, and changes in nutrient TN and TP were investigated. The metal contents of the culture solution, algal cells, and four tissues of Ruditapes philippinarum were analyzed. The results showed that the highest nutrient removal efficiency was achieved under the co-culture of three heavy metals, with the removal rates of TN and TP ranging from 47.26% to 51.36% and 78.28% to 87.72%, respectively. The higher tolerance of Chlorella sp. to heavy metals compared to Isochrysis zhangjiangensis was probably due to the higher glutathione and super oxide dimutase activities exhibited by Chlorella sp. cells, which increased by 28% and 40.64%, respectively. Isochrysis zhanjiangensis, Chlorella sp. and their co-culture group had the highest removal rate of Pb2+, which were 20.15%, 26.56% and 29.19%, respectively, followed by Cd2+ and Cu2+. The enrichment of the four tissues from the Ruditapes philippinarum organism for heavy metals, was in the order of visceral mass > gill > coat membrane > muscle. The biotransfer coefficients of the three metals in the microalgae-Ruditapes philippinarum food chain biomagnification ranged from 0.24 to 0.79, which indicated that there was no significant biomagnification of the metals in the transfer process of the food chain. The results of this study reveal the mechanism of heavy metal transport in the algae-shellfish system, which would provide a theoretical basis for improving the ecological environment, and can improve the quality of cultured shellfish products.

Progress In Stem Cells Based Replacement Therapy for Retinal Pigment Epithelium: In Vitro Differentiation to In Vivo Delivery.

Retinal pigment epithelium (RPE) is a critical cell monolayer forming the blood-retina-barrier (BRB) and a permeable bridge between the choriocapillaris and the retina. RPE is also crucial in maintaining photoreceptor function and for completing the visual cycle. Loss of the RPE is associated with the development of degenerative diseases like age-related macular degeneration (AMD). To treat diseases like AMD, pluripotent stem cell-derived RPE (pRPE) has been recently explored extensively as a regenerative module. pRPE like other ectodermal tissues requires specific lineage differentiation and long-term in vitro culturing for maturation. Therefore, understanding the differentiation process of RPE could be useful for stem cell based RPE derivation. Developing pRPE-based transplants and delivering them into the subretinal space is another aspect that has garnered interest in the last decade. In this review, we discuss the basic strategies currently employed for stem cell-based RPE derivation, their delivery, and recent clinical studies related to pRPE transplantation in patients. We have also discussed a few limitations with in vitro RPE culture and potential solutions to overcome such problems which can be helpful in developing functional RPE tissue.

All-in-one coupling of 3D hybridized nanocarbon microelectrode for portable monitoring of doxycycline hyclate

The simultaneous balance of electrode materials and electrode structures can energize the development of innovative electrochemical sensors. In this work, a 3D nanocarbon layer of hybrid heteroatoms and metal atoms (CN/Fe) with excellent electrical properties and abundant active sites was self-constructed on the surface of a quartz-based nanofiber by high-temperature pyrolysis. Further, the nanofiber tip was selected as the sensing region to develop an electrochemical sensing platform with high sensitivity, miniaturization, and portability. A common broad-spectrum antibiotic (Doxycycline hyclate, DOX) was used as a model to evaluate the designed miniaturized sensing platform, and the stability, reproducibility, and applicability of the microsensor were verified in a variety of real samples, including algal solution, milk, human serum, and cell culture media. The results show that the proposed sensing platform has a detection limit as low as 82 nM in aqueous environments. Furthermore, it is further shown that coupling the design of electrode materials and electrode structures facilitates the development of electrochemical sensors with more practical applications. This concept will open up new avenues for the development of electrochemical sensors that meet many application scenarios.

Antibacterial activity mechanism of coptisine against Pasteurella multocida.

Pasteurella multocida is a widespread zoonotic pathogen that causes severe damage to the poultry industry. This study focused on the antibacterial effects and mechanism of action of coptisine against P. multocida. The minimum inhibitory concentration and half maximal inhibitory concentration of coptisine against P. multocida was measured. Additionally, the effect of coptisine on growth, cell wall, activity of respiratory enzymes, soluble protein content and DNA synthesis were also analyzed. Finally, the effect of coptisine on gene transcription was determined using RNA sequencing. We demonstrated that coptisine has a strong antibacterial effect against P. multocida, with a minimum inhibitory concentration of 0.125 mg/mL. Moreover, the measurement of the half maximal inhibitory concentration confirmed that coptisine was safe for the pathogen. The growth curve showed that coptisine inhibited bacterial growth. Measurement of alkaline phosphatase activity in the culture solution showed that coptisine affected cell wall permeability. Transmission electron microscopy revealed that coptisine chloride destroyed the cell structure. In addition, coptisine blocked the respiratory system, as measured by the levels of critical enzymes of the tricarboxylic acid cycle and glycolysis, succinate dehydrogenase and lactate dehydrogenase, respectively. Similarly, coptisine inhibited the synthesis of soluble proteins and genomic DNA. The KEGG pathway analysis of the differentially expressed genes showed that they were associated with cellular, respiratory, and amino acid metabolism, which were downregulated after coptisine treatment. Additionally, genes related to RNA degradation and the aminoacyl-tRNA pathway were upregulated. In this study, we demonstrated that coptisine exerts an antibacterial effect on P. multocida. These findings suggest that coptisine has a multifaceted impact on various pathways, resulting in the inhibition of P. multocida. Thus, coptisine is a potential alternative to antibiotics for the treatment of P. multocida infections in a clinical setting.

Use of silicon in the production of tomato (Lycopersicon esculentum Mill.) grape type in nutritive solution cultivation

The objective of the research was to evaluate the effect of silicon concentration and application method on growth and yield of grape tomato plants. An experiment was established under shade net conditions in solution culture. The factors evaluated were silicon concentration (0, 4, 6, 6, 8 and 10 g.L-1 ) and application methods (to the nutrient solution and foliar). Nutrition was applied by irrigation of the universal nutrient solution (Steiner, 1984), at a concentration of 75%. The total number of treatments was 10. The design was completely randomized with four replications per treatment and based on the treatments, the following variables: plant height, root length, stem diameter, number of leaves, leaf area, fresh and dry weight of aerial and root biomass, number of fruits per plant, total yield and fruit diameter, length and weight. For the variables evaluated, it was identified that the concentration of 8 g.L-1 of SiO2 applied to the root was the one that obtained the best value to favor vegetative growth and to obtain a greater fruit development for grape tomato plants of the Primarino variety.

Effects of Phosphorus Deficiency on Ion Transport And Its Anatomical Relation in Mung Bean (Vigna Radiata L.)

Effects of phosphorus deficiency on ion transport and its relation with anatomical structure in mungbean plants were investigated. Phosphorous deficiency caused an increase in the accumulation of K+ in the root and a decrease in the stem and leaf of mungbean seedlings grown in solution culture. Na+ and NO3 - accumulation was increased in the root, stem and leaf of P-deficient plant. On the contrary, accumulation of PO4 3- was decreased in root, stem and leaf under P-deficiency treatment. The diameter of root was decreased under phosphorus deficiency. Vascular area was found to decrease and occupied less area with smaller size of metaxylem cavity in the root and stem of mungbean plant. In phosphorus deficient plant, phloem elements were poorly developed and occupied smaller area. Bangladesh J. Bot. 52(2): 381-387, 2023 (June)

Predictive Cell Culture Time Evolution Based on Electric Models.

Obtaining cell concentration measurements from a culture assay by using bioimpedance is a very useful method that can be used to translate impedances to cell concentration values. The purpose of this study was to find a method to obtain the cell concentration values of a given cell culture assay in real time by using an oscillator as the measurement circuit. From a basic cell-electrode model, enhanced models of a cell culture immersed in a saline solution (culture medium) were derived. These models were used as part of a fitting routine to estimate the cell concentration in a cell culture in real time by using the oscillation frequency and amplitude delivered by the measurement circuits proposed by previous authors. Using real experimental data (the frequency and amplitude of oscillations) that were obtained by connecting the cell culture to an oscillator as the load, the fitting routine was simulated, and real-time data of the cell concentration were obtained. These results were compared to concentration data that were obtained by using traditional optical methods for counting. In addition, the error that we obtained was divided and analyzed in two parts: the first part of the experiment (when the few cells were adapting to the culture medium) and the second part of the experiment (when the cells exponentially grew until they completely covered the well). Low error values were obtained during the growth phase of the cell culture (the relevant phase); therefore, the results obtained were considered promising and show that the fitting routine is valid and that the cell concentration can be measured in real time by using an oscillator.