Strain-specific features of Pleurotus ostreatus growth in vitro and some of its biological activities.

BACKGROUND: The production of Pleurotus ostreatus mycelium as a promising object for use in food and other industries is hampered by a lack of information about the strain-specificity of this fungus mycelium growth and its acquisition of various biological activities. Therefore, this research aimed to investigate mycelial growth of different P. ostreatus strains on varies solid and liquid media as well as to evaluate strains antagonistic, antibacterial, antiradical scavenging activities, and total phenolic content. RESULTS: Potato Dextrose Agar medium was suitable for all strains except P. ostreatus strain 2460. The best growth rate of P. ostreatus 2462 strain on solid culture media was 15.0 ± 0.8 mm/day, and mycelia best growth on liquid culture media-36.5 ± 0.2 g/l. P. ostreatus strains 551 and 1685 were more susceptible to positive effect of plant growth regulators Ivin, Methyur and Kamethur. Using of nutrient media based on combination of natural waste (amaranth flour cake and wheat germ, wheat bran, broken vermicelli and crumbs) has been increased the yield of P. ostreatus strains mycelium by 2.2-2.9 times compared to the control. All used P. ostreatus strains displayed strong antagonistic activity in co-cultivation with Aspergillus niger, Candida albicans, Issatchenkia orientalis, Fusarium poae, Microdochium nivale in dual-culture assay. P. ostreatus 2462 EtOAc mycelial extract good inhibited growth of Escherichia coli (17.0 ± 0.9 mm) while P. ostreatus 2460 suppressed Staphylococcus aureus growth (21.5 ± 0.5 mm) by agar well diffusion method. The highest radical scavenging effect displayed both mycelial extracts (EtOH and EtOAc) of P. ostreatus 1685 (61 and 56%) by DPPH assay as well as high phenolic content (7.17 and 6.73 mg GAE/g) by the Folin-Ciocalteu's method. The maximal total phenol content (7.52 mg GAE/g) demonstrated of P. ostreatus 2461 EtOH extract. CONCLUSIONS: It is found that the growth, antibacterial, antiradical scavenging activity as well as total phenolic content were dependent on studied P. ostreatus strains in contrast to antagonistic activity. The proposed culture mediums of natural waste could be an alternative to commercial mediums for the production mycelial biomass of P. ostreatus strains.

Characteristic quality analysis for biologically induced agarwood columns in Aquilaria sinensis.

Current artificial agarwood-inducing techniques yield low quality and quantities of agarwood. On account of unclear agarwood formation mechanism there's still no high-efficiency agarwood inducing method globally spread. In this study, a complete agarwood column was taken out of the live tree trunk at 6 months post-treatment by a novel agarwood-inducing method (Agar-Bit) in cultivated Aquilaria sinensis trees, and was first divided into 8 parts (A1-4, B1-4) involving agarwood layer (A part) and brown inner layer (B part) according to its color and length for analysis. These eight parts were analyzed microscope observation, 6 chromones' contents and characteristic chromatograms by HPLC (high performance liquid chromatography), GC-MS (gas chromatography-mass spectrometer) with to determine chemical changes. Other quality characteristics, TLC (thin-layer chromatography) and alcohol soluble extraction content, were also determined. Our results showed that resin changed with A to B part and microstructure changed with length. Six chromones in the eight parts varied with layers. Result of characteristic chromatograms showed that both A and B parts contained six characteristic peaks. Volatile component distributed mainly in A part, but important chromones were also detected in B parts. Results from TLC and alcohol soluble extraction content also showed that B part contained characteristic compounds of agarwood. In addition, some compounds in the essential oil detected by GC-MS in A part produced by Agar-Bit were similar to that found in natural agarwood, compounds in B parts were similar to BC agarwood, as were the results for the TLC and alcohol soluble extraction content. In conclusion, the chemical distribution obtained here from Agar-Bit could provide some clues to optimize high production and high efficiency stimulating method for whole tree full of resin in Aquilaria sinensis and to reveal the subtle agarwood formation mechanism throughout a whole trunk.

Curative anti-typhoid effect of Detarium microcarpum Guill. & Perr. (Leguminosae) hydroethanolic extract root bark based-on in vivo and molecular docking analyses.

ETHNOPHARMACOLOGICAL RELEVANCE: Detarium microcarpum is used to treat typhoid fever, a major public health problem, by indigenous population in Africa. Though its preventive activities have been documented, the curative effect is still to be confirmed. AIM OF THE STUDY: This study aimed at evaluating the curative effects of the hydroethanolic extract of Detarium microcarpum root bark on Salmonella typhimurium-induced typhoid in rat and exploring the in-silico inhibition of some bacterial key enzymes. STUDY DESIGN: In vitro antioxydant, in vivo antisalmonella of the extract and in silico molecular docking assay on the isolated compounds were carried out to explore the anti-salmonella effects of Detarium microcarpum. MATERIAL AND METHODS: The in vitro antioxidant properties of the extract were evaluated using DPPH, ABTS and FRAP tests. The anti-salmonella activity of the extract was assessed through feacal sample from Salmonella typhimurium-infected rat cultured in Salmonella-Shigella agar (SS agar) medium. The affinity of isolated compounds (Rhinocerotinoic acid and Microcarposide) from the extract were performed on four key enzymes (Adenylosuccinate lyase, Acetyl coenzyme A synthetase, Thymidine phosphorylase and LuxS-Quorum sensor) using molecular docking simulation to elucidate the molecular level inhibition mechanism. RESULTS: Crude extract of D. microcarpum root bark showed variable activities on DPPH (RSa50: 6.09 ± 1.04 µg/mL), ABTS (RSa50: 24.46 ± 0.27), and FRAP (RSa50: 23.30 ± 0.23). The extract at all the doses exhibited significant healing effect of infected rats, with the complete clearance. The extract restored hematological, biochemical and histological parameters closed to the normal control. The molecular docking results indicates that rhinocerotinoic acid and microcarposide present more affinity to the LuxS-Quorum sensor and Acetyl coenzyme A synthetase protein as compared to the others. CONCLUSION: These results demonstrate potent anti-typhoid activities of the hydroethanolic of Detarium microcarpum root bark extract through antioxidant properties and high inhibitory affinity of its compounds on some bacterial key enzymes that justify its use as traditional medicine to typhoid fever.

Seaweed polysaccharides: Emerging extraction technologies, chemical modifications and bioactive properties.

Nowadays, consumers are increasingly aware of the relationship between diet and health, showing a greater preference of products from natural origin. In the last decade, seaweeds have outlined as one of the natural sources with more potential to obtain bioactive carbohydrates. Numerous seaweed polysaccharides have aroused the interest of the scientific community, due to their biological activities and their high potential on biomedical, functional food and technological applications. To obtain polysaccharides from seaweeds, it is necessary to find methodologies that improve both yield and quality and that they are profitable. Nowadays, environmentally friendly extraction technologies are a viable alternative to conventional methods for obtaining these products, providing several advantages like reduced number of solvents, energy and time. On the other hand, chemical modification of their structure is a useful approach to improve their solubility and biological properties, and thus enhance the extent of their potential applications since some uses of polysaccharides are still limited. The present review aimed to compile current information about the most relevant seaweed polysaccharides, available extraction and modification methods, as well as a summary of their biological activities, to evaluate knowledge gaps and future trends for the industrial applications of these compounds.Key teaching pointsStructure and biological functions of main seaweed polysaccharides.Emerging extraction methods for sulfate polysaccharides.Chemical modification of seaweeds polysaccharides.Potential industrial applications of seaweed polysaccharides.Biological activities, knowledge gaps and future trends of seaweed polysaccharides.

Development of low-cost edible coatings based on polysaccharides with active lactic acid bacteria for the protection of fresh produce modeled using fresh cut apples.

The loss of fresh produce along the supply chain represents a significant contributor to environmental and economic burden. Although technological advances in distribution and storage have provided a means to reduce the loss of fresh produce, in resource-limited settings, these technologies may not be available. One attractive approach to help address this limitation is to use edible coatings to protect fresh produce from biotic and abiotic factors that cause food deterioration. Here, we developed edible coatings from materials that are cheap and easy to prepare: maize starch, κ-carrageenan, and agar as the matrix; glycerol as the plasticizer; and Lactobacillus plantarum TPB21.12 as the active ingredient. Using fresh cut apples as a model substrate, we found that maize starch coating retained color, agar coating delayed browning, and κ-carrageenan coating decreased mass shrinkage of the fresh cut apples. L. plantarum TPB21.12 remained viable in the edible coating suspensions during storage and was active against Escherichia coli TPB21.8, a model bacterium for biotic factor that causes food spoilage. The simplicity of the edible coating formulation and preparation method offers an attractive approach for applications to help protect fresh produce from deterioration and reduce food loss and waste generation.

Morphometric and gut microbial evaluation of Tilapia (Oreochromis niloticus) fed on different levels of Moringa oleifera.

In current study, different feeding levels of Moringa oleifera formulated diet was compared to analyze the growth performance, feed conversion ratio, feed conversion efficiency and gut microbiology of Oreochromis niloticus. The study was comprised of four treatment groups including 4%, 8% and 12% Moringa oleifera and one control group which was devoid of Moringa leaves. The experimental trial was conducted at the Zoology laboratory of Pakistan Institute of Applied and Social Sciences, (PIASS) Kasur. The physicochemical parameters of water such as temperature, dissolve oxygen, pH, total dissolved solids and salinity in all aquaria were found non-significantly different from each other. In control condition T1, the average weight gain was 14.89±16.90a grams, while average length gain was 11.52±7.444a cm. However, the total viable count on Eosin methylene blue was 7.4×107, 5.8×107 on Tryptic soy agar and 5.8×107on Nutrient agar. In T2, the average weight gain was 16.22±16.09b grams and average length gain was 12.97±7.79b cm. The total viable count on Eosin methylene blue was 7×107, 5.5×107 on Tryptic soy agar and 5.8×107on Nutrient agar. In T3, the average weight gain was 37.88±27.43c grams, while the average length gain was recorded as 16.48±12.56c cm. However, the total viable count for treatment 3 was 6.4×10 on Eosin methylene blue, 4.8×107 on Tryptic soy agar and 5.2×107on Nutrient agar. In T4, the average weight gain was 44.22±31.67d grams, while the average length gain was 15.25±10.49d cm. The total viable count was 4.3×107on Eosin methylene blue, 3.1×107 on Tryptic soy agar and 3.8×107 on Nutrient agar. The effect of Moringa oleifera on the growth of Oreochromis niloticus was found to be significant and 12% Moringa extract showed maximum length and weight gain and minimum feed conversion ratio with the least microbial count in fish intestine.

The effects of ultrasonic treated whey on the structure formation in food systems based on whey in combination with pectin and agar-agar.

We studied the effects of ultrasonicated whey in food systems with the structure-forming additives such as pectin and agar-agar. The high-intensity (45KHz, 40 W with cavitation) ultrasonic treated whey was used. The conditions and optimal modes of cavitation based ultrasonic processing of curd milk whey have been determined. The mechanism of structure formation has been studied in detail. From the studies carried out, the scientific basis for the choice of structure-forming agents in food systems was established along with the range of rational concentrations of pectin and agar-agar. It was shown that in the case of processing milk curd whey by the cavitation method, the concentration of the structure former can be reduced by 2 times compared to using non-sonicated whey in the food system thus saving costs on the raw materials. It was established that high-purity cavity treatment minimizes gel-like food systems set time up to 20% compared to the control within 15 min. The duration of high-purity treatment within 15 min contributes to an increase in penetration pressure, which characterizes the texture of the gel-like food two times.

Incorporation of chlorhexidine in self-adhesive resin cements.

The aim of this study was to evaluate the maximum amount of chlorhexidine (CHX) that could be incorporated to self-adhesive resin cements to add antibacterial effect without affecting the physical properties. The CHX was incorporated into a commercial self-adhesive resin cement at mass fractions of 0.5-15 wt%, and the CHX-release profile, antibacterial effect, flexural and bond strengths of experimental cements were evaluated. Increasing the CHX content from 5 to 15 wt% resulted in a higher released concentration of CHX. In agar diffusion tests, experimental cements containing 5, 10, and 15 wt% CHX produced inhibition zones against oral bacteria. In flexural strength and shear bond strength to dentin, no significant reduction was observed with the incorporation of 5 wt% CHX. This in vitro study suggests that the addition of 5 wt% CHX yielded an antibacterial self-adhesive cement and had no adverse effect on the flexural and shear bond strengths.

Fatores de virulência e susceptibilidade a antifúngicos de Cryptococcus Spp / Virulence factors and susceptibility to Cryptococcus Spp. antifungals

Criptococose é uma doença grave que afeta tanto imunocomprometidos quanto imunocompetentes, com isso analisar a virulência é fundamental para novas terapêuticas. Objetivo: Analisar a capacidade de virulência e susceptibilidade aos antifúngicos de Cryptococcus spp. isolados de líquor de pacientes de hospital do norte do Paraná. Métodos: A partir de dois isolados clínicos C. neoformans e C. gattii, realizou-se a confirmação da identificação. Para a virulência, avaliou-se o tamanho da cápsula, capacidade de sobrevivência após exposição a neutrófilos, produção de melanina e urease. No antifungigrama por difusão em disco utilizou-se: anfotericina B, cetoconazol, voriconazol, itraconazol e miconazol. Resultados: C. gattii destaca-se por maior desenvolvimento da cápsula além da melhor capacidade de sobreviver a fagocitose em relação ao C. neoformans. No antifungigrama, ambos os isolados se apresentam sensíveis às drogas estudadas. Conclusão: Esses achados contribuem para a compreensão das diferentes patogêneses entre C. gattii e C. neoformans.

Cryptococcosis is a serious disease that can affect both immunocompromised and immunocompetent individuals, thus the virulence analysis is fundamental for the development of new treatments. Objective: To analyze the virulence and susceptibility of Cryptococcus spp. isolated from cerebrospinal fluid of patients from a hospital in the north of Paraná. Methods: From two clinical isolates, C. neoformans and C. gattii were confirmed and identified. For virulence, capsule size, survival capacity after exposure to neutrophils, melanin production and urease were evaluated. In the disc-diffusion method, the following antifungals were used: amphotericin B, ketoconazole, voriconazole, itraconazole and miconazole Results: It was observed that C. gattii presents greater results for development of the capsule beside presenting the best ability to survive phagocytosis in relation to C. neoformans. In the disc-diffusion method, both isolates presented sensitivity to the studied drugs. Conclusion: These findings contribute to the understanding of the different pathogens between C. gattii and C. neoformans.

Comparison of nine different selective agars for the detection of carbapenemase-producing Enterobacterales (CPE).

The rapid identification of patients colonized with carbapenem-resistant Enterobacterales (CRE) is important for infection control purposes. Here, we compared and evaluated nine different agars for the detection of carbapenemase-producing Enterobacterales (CPE) from clinical samples. In the study, 69 CPE and 40 carbapenemase-negative isolates were included. Overall, seven commercially available screening agars were assessed: Brilliance CRE (Oxoid), Chromatic CRE (Liofilchem), chromID CARBA and chromID OXA-48 (both bioMérieux), three ESBL agars (Chromatic ESBL [Liofilchem], chromID ESBL [bioMérieux], Brilliance ESBL [Oxoid]), and two agars produced in-house (McCARB and McCARB-T). The sensitivity of CRE agars for CPE detection ranged from 34.8 to 98.6%. Brilliance CRE and McCARB/McCARB-T showed the overall highest sensitivity (98.6 and 97.1%, respectively). OXA-48 producers were the most difficult to detect; only 4/9 agars detected all isolates (McCARB/McCARB-T, Chromatic CRE, ChromID OXA-48). Additionally, all ESBL-negative OXA-48 isolates failed to grow on ESBL screening agars. Specificity ranged from 30 (Brilliance ESBL) to 100% (ChromID OXA-48). The limit of detection for different CPE in spiked stool samples ranged from 1.5 × 101 to 1.5 × 103 CFU/ml. Overall, Brilliance CRE and the McCARB in-house agars showed the best performance and were able to detect most CPE, including almost all OXA-48. ESBL agars were not suitable for detection of CPE alone, as OXA-48 isolates negative for ESBL were suppressed. The highest sensitivity was achieved by a combination of a CRE agar and an ESBL agar.

Acinetobacter baumannii detected on modified charcoal-cefoperazone-deoxycholate agar in a waste stabilization pond.

Campylobacter is a recommended reference pathogen for the verification and validation of water recycling schemes in Australia and globally. In a larger study investigating the efficacy of pathogen removal in waste stabilization ponds (WSP), we cultivated bacteria from wastewater samples on modified charcoal-cefoperazone-deoxycholate agar (mCCDA) targeting the growth of Campylobacter. A high number of colonies characteristic of Campylobacter grew on this selective medium, but this did not correlate with qPCR data. Using primers targeting the 16S rRNA gene, and additional confirmatory tests to detect VS1, ompA, blaOXA-51-like, blaOXA-23-like genes, we tested 80 random colonies from 10 WSP samples. All 80 were identified as Acinetobacter baumannii. Wastewater grab samples taken three times over 6 months throughout the WSP system showed removal of A. baumannii in the WSP at rates similar to that of Escherichia coli. Our study suggests that mCCDA agar is not a suitable medium for isolating Campylobacter from environmental samples and that A. baumannii can be used as an indicator for removal of pathogens in WSPs.

NMR-based metabolomics reveals the metabolite profiles of Vibrio parahaemolyticus under blood agar stimulation.

Vibrio parahemolyticus is a halophilic bacterium which causes widespread seafood poisoning pathogenicity. Although the incidence of disease caused by V. parahemolyticus was stepwise increased, the pathogenic mechanism remained unclear. Herein, the difference of V. parahemolyticus's metabonomic which on blood agar and seawater beef extract peptone medium was detected via nuclear magnetic resonance and 55 metabolites were identified. Among them, 40 kinds of metabolites were upregulated in blood agar group, and 12 kinds were downregulated. Nine pathways were verified by enrichment analysis which were predicted involved in amino acids and protein synthesis, energy metabolism, DNA and RNA synthesis and DNA damage repair. We supposed that the metabolic pathway obtained from this study is related to V. parahemolyticus pathogenicity and our findings will aid in the identification of alternative targets or strategies to treat V. parahemolyticus-caused disease.

Study of zinc oxide nanoparticles and zinc chloride toxicity to annelid Enchytraeus crypticus in modified agar-based media.

Acute toxicity of zinc oxide nanoparticle (ZnO-NP, mean particle size diameter of 10 nm) powder and water-soluble salt of zinc (ZnCl2) to annelid Enchytraeus crypticus was tested using an agar-based nutrient-enriched medium with the addition of kaolin and humic acids (HA). Adults of the E. crypticus were cultivated in pure agar and in three types of modified exposure media containing different proportions of model soil constituents. Potworms were exposed to zinc in both forms (1-1000 mg kg-1 of agar) for 96 h. In experiments with ZnCl2, toxicity of zinc was the highest in pure agar followed by agar with HA and agar with kaolin and HA and the lowest toxicity was observed in agar with kaolin. The corresponding LC50 values were 13.2, 28.8, 39.4, and 75.4 mg kg-1 respectively. In contrast, zinc in the form of ZnO-NPs was most toxic in the presence of HA followed by pure agar, agar with kaolin, and kaolin with HA. In this case, LC50 values were 15.8, 43.5, 111, and 122 mg kg-1 respectively. Scanning electron microscopy revealed that the smallest agglomerates occurred in the presence of kaolin, where ZnO-NPs were sealed in a kaolin shell. This effect reduced the bioavailability and toxicity of the NPs. In contrast, larger agglomerates were observed in the presence of HA but a larger amount of zinc was dispersed in the volume of agar.

Formulation of maize- and peanut-based semi-synthetic growth media for the ecophysiological studies of aflatoxigenic Aspergillus flavus in maize and peanut agro-ecosystems.

In studying the ecophysiology of fungal phytopathogens, several stages are involved (in vitro, greenhouse, in planta). Most in vitro studies extensively utilise the general growth media such as Potato Dextrose Agar and Malt Extract Agar. Although the crop components in these media serve as excellent carbon sources and yield luxuriant growth, they are not naturally contaminated with Aspergillus flavus and thus might result in under- or overestimation of its actual toxigenic potentials. Empirical data on the formulation of semi-synthetic growth medium mimicking the natural crop commonly contaminated by A. flavus for the ecophysiological studies in vitro are scarce. The present work was aimed at investigating the ecophysiology of A. flavus on commercial growth media (PDA, MEA); formulating maize- and peanut-based semi-synthetic growth media using two methods of raw material preparation (milling, hot water extraction) at different concentrations (1, 3, 5, 7, 9% w/v), and comparing the ecophysiological parameters between commercial and formulated growth media. Growth rates were obtained by computing the hyphal expansion data into y = mx + c equation. AFB1 was quantified using high performance liquid chromatography with fluorescence detector. Formulated media were found to yield significantly higher growth rates when compared to commercial media. However, commercial media yielded significantly higher AFB1 when compared to all formulated media. Between the two formulations, milling yielded significantly higher growth rates and AFB1 when compared to hot water extraction. Although in vitro data cannot directly extrapolate in planta performance, results obtained in the present work can be used to gauge the actual toxigenic potential of A. flavus in maize and peanut agro-ecosystems.

Rapid and non-invasive detection and imaging of the hydrocolloid-injected prawns with low-field NMR and MRI.

Method development for monitoring economically motivated food adulteration is pivotal for preventing health problems caused by illegal food additives. In this work, low-field nuclear magnetic resonance (LF-NMR) spectroscopy and magnetic resonance imaging (MRI) was applied for the detection and mapping of adulterated prawns injected with different hydrocolloids including gelatin, carrageenan, agar, amorophophallus konjac and xanthan gum. The characteristic T2 fitting curves were obtained which can be used to tell apart adulterated prawns from normal ones. Furthermore, the benefit from high quality LF-MRI images showed the major accumulation site of the hydrocolloids injected in prawn. The location of these injections was mainly confined to well resolved accumulation in brain region and three following subtle sites: back, tail and claws. Different hydrocolloids can be successfully distinguished in adulterated prawns with principal component analysis. Therefore, rapid, non-invasive and low-cost LF-NMR technique offers a powerful tool for the identification of hydrocolloids adulteration in real-time.

Importance of the agar-media in the evaluation of bacteriocin activity against the same test-microorganisms

Abstract Bacteriocins are peptides produced by various species of bacteria, especially lactic acid bacteria, which exhibit a large spectrum of action against spoilage bacteria and foodborne pathogens. Successful application of techniques for quantitative or qualitative bacteriocin determination relies not only on the sensitivity of the test-microorganisms, but also on the agar-medium employed. Cell free supernatants are routinely used to preliminary screen for antimicrobial activity of bacteria by means of the agar well diffusion method, but the supernatant may also include other molecules (such as medium components and/or intracellular compounds) accidentally released during cell free supernatant preparation, which may interfere with the assay. Reproducibility of bacteriocin activity against the same test-microorganisms is an important factor to be considered. Unfortunately, no specific information about bioassays standardization to determine bacteriocin activity is available in the literature. In this work, growth inhibition by means of the agar well diffusion assays were carried out on different agar-media showing a strong dependence on the agar-medium used, indicating that the inhibitory effects could also depend on the diffusion of exudates that are included in the cell-free supernatant. The results presented in this communication show that selection of the agar-medium is crucial for the bioassay response.

Peritonitis por Moraxella osloensis: a propósito de un caso y revisión de la literatura / Moraxella osloensis peritonitis: case report and review

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Cutaneous abscess due to Gordonia bronchialis: case report and literature review / Absceso cutáneo por Gordonia bronchialis: descripción de un caso y revisión de la literatura

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Effect of minerals on accumulation of Cs by fungus Saccaromyces cerevisiae.

The accumulation of Cs by unicellular fungus of Saccharomyces cerevisiae in the presence of minerals has been studied to elucidate the role of microorganisms in the migration of radioactive Cs in the environment. Two different types of experiments were employed: experiments using stable Cs to examine the effect of a carbon source on the accumulation of Cs, and accumulation experiments of radioactive Cs from agar medium containing (137)Cs and zeolite, vermiculite, phlogopite, smectite, mica, or illite as mineral supplements. In the former type of experiments, the Cs-accumulated cells were analyzed by scanning electron microscopy equipped with energy dispersive X-ray analysis (SEM-EDS). In the latter type, the radioactivity in the yeast cells was measured by an autoradiography technique. When a carbon source was present, higher amounts of Cs accumulated in the cells than in the resting condition without a carbon source. Analyses with SEM-EDS showed that no mineral formed on the cell surface. These results indicate that the yeast cells accumulate Cs by adsorption on the cell surface and intracellular accumulation. In the presence of minerals in the agar medium, the radioactivity in the yeast cells was in the order of mica > smectite, illite >> vermiculite, phlogopite, zeolite. This order is inversely correlated to the ratio of the concentration of radioactive Cs between the minerals and the medium solution. These results strongly suggest that the yeast accumulates radioactive Cs competitively with minerals.