Growth Medium Research Articles

Isolation and evaluation of probiotics from traditional Chinese foods for aflatoxin B1 detoxification: Geotrichum candidum XG1 (yeast) and mechanistic insights

Identifying aflatoxin-detoxifying probiotics remains a significant challenge in mitigating the risks associated with aflatoxin contamination in crops. Biological detoxification is a popular technique that reduces mycotoxin hazards and garners consumer acceptance. Through multiple rounds of screening and validation tests, Geotrichum candidum XG1 demonstrated the ability to degrade aflatoxin B1 (AFB1) by 99–100%, exceeding the capabilities of mere adsorption mechanisms. Notably, the degradation efficiency was demonstrably influenced by the presence of copper and iron ions in the liquid medium, suggesting a potential role for proteases in the degradation process. Subsequent validation experiments with red pepper revealed an 83% reduction in AFB1 levels following fermentation with G. candidum XG1. Furthermore, mass spectrometry analysis confirmed the disruption of the AFB1 furan ring structure, leading to a subsequent reduction in its toxicity. Collectively, these findings establish G. candidum XG1 as a promising candidate for effective aflatoxin degradation, with potential applications within the food industry.

NRASQ61R mutation drives elevated angiopoietin-2 expression in human endothelial cells and a genetic mouse model.

Angiopoietin-2 (Ang-2) is increased in the blood of patients with kaposiform lymphangiomatosis (KLA) and kaposiform hemangioendothelioma (KHE). While the genetic causes of KHE are not clear, a somatic activating NRASQ61R mutation has been found in the lesions of KLA patients. Our study tested the hypothesis that the NRASQ61R mutation drives elevated Ang-2 expression in endothelial cells. Ang-2 was measured in human endothelial progenitor cells (EPC) expressing NRASQ61R and a genetic mouse model with endothelial targeted NRASQ61R. To determine the signaling pathways driving Ang-2, NRASQ61R EPC were treated with signaling pathway inhibitors. Ang-2 levels were increased in EPC expressing NRASQ61R compared to NRASWT by Western blot analysis of cell lysates and ELISA of the cell culture media. Ang-2 levels were elevated in the blood of NRASQ61R mutant mice. NRASQ61R mutant mice also had reduced platelet counts and splenomegaly with hypervascular lesions, like some KLA patients. mTOR inhibitor rapamycin attenuated Ang-2 expression by NRASQ61R EPC. However, MEK1/2 inhibitor trametinib was more effective blocking increases in Ang-2. Our studies show that the NRASQ61R mutation in endothelial cells induces Ang-2 expression in vitro and in vivo. In cultured human endothelial cells, NRASQ61R drives elevated Ang-2 through MAP kinase and mTOR-dependent signaling pathways.

Engineering Rapeseed Germination and Root Growth with Mechanical Strength of Polysaccharide Hydrogel.

Plant roots are highly sensitive to physical stress in the soil, with appropriate mechanical impedance promoting root elongation and lateral root growth. However, few studies have quantitatively explored the relationship between the mechanical impedance of the growth medium and the phenotypes of plant roots. In this study, we used a tensile machine equipped with a self-made steel needle mimicking the root tip to measure the force needed to penetrate the hydrogel medium (agar, low acyl gellan gum, and κ-carrageenan), providing insights into the force required for the rapeseed root tip to enter the medium following germination. These findings indicate that root penetration length is inversely associated with the mechanical strength of the growth medium, with variations observed in the root system adaptability across different substrates. Specifically, when the gel puncture resistance of the culture medium without adding MS reached approximately 18.4 mN, root penetration and growth were significantly hindered. With the addition of 1/2 MS medium, the polysaccharide concentration is 1.0 wt %, which is more suitable for cultivating rapeseed. This research not only offers a method for quantifying root phenotypes and medium mechanical impedance but also presents an approach for plant growth regulation and crop breeding.

Environmental Homeopathy: Homeopathic Potencies Regulate the Growth and Toxicity of Raphidiopsis raciborskii (cyanobacteria) and Can be Tracked Physico-Chemically. Part 2: Physico-chemical Results.

The control of cyanobacterial toxicity and growth by homeopathic potencies was described in Part 1 of this two-part report. Here, a parallel approach characterized the physico-chemical features of the potencies used and the liquid media treated with them, correlating these results with their respective biological effects. Our objective was to establish if physico-chemical parameters can track homeopathic potencies in seawater or artificial seawater medium (ASM)-1 and to discover whether these parameters correlate with previously described biological effects. Artemia franciscana (brine shrimp) cysts were cultivated in seawater challenged with Raphidiopsis raciborskii extract and treated with different homeopathic potencies chosen from a screening process. Cultures of R. raciborskii maintained in ASM-1 were also treated with previously screened homeopathic potencies, and their growth was monitored as a function of time. The physico-chemical properties of the treated media (seawater or ASM-1) were evaluated by their interaction with solvatochromic dyes and changes in pH, conductivity and temperature. Coumarin 7 was found to be a marker for Nitric acidum 6cH and Isotherapic (R. raciborskii extract) 200cH in seawater (analysis of variance [ANOVA], p = 0.0015). Nile red was found to be a marker for Nitric acidum 200cH and Mercurius solubilis 30cH in ASM-1 (ANOVA, p ≤ 0.001). An increase in pH of ASM-1 and endothermic effects were observed after these treatments (two-way ANOVA, p = 0.0001). Seawater and ASM-1 to which potencies had been added were also subjected to a constant unidirectional 2,400 Gauss static magnetic field and found to have enhanced effects on the solvatochromic dyes tested. Homeopathic potencies were specifically traceable in aqueous media using solvatochromic dyes, especially when the samples were subjected to a magnetic field. Results from monitoring other physical parameters, such as pH and temperature, were less specific in relation to potency tracking. However, potency-induced endothermic effects might provide valuable thermodynamic data relating to the nature of potencies.

Light-Emitting Diodes and Liquid System Affect the Caffeoylquinic Acid Derivative and Flavonoid Production and Shoot Growth of Rhaponticum carthamoides (Willd.) Iljin.

Plant in vitro cultures can be an effective tool in obtaining desired specialized metabolites. The purpose of this study was to evaluate the effect of light-emitting diodes (LEDs) on phenolic compounds in Rhaponticum carthamoides shoots cultured in vitro. R. carthamoides is an endemic and medicinal plant at risk of extinction due to the massive harvesting of its roots and rhizomes from the natural environment. The shoots were cultured on an agar-solidified and liquid-agitated Murashige and Skoog's medium supplemented with 0.1 mg/L of indole-3-acetic acid (IAA) and 0.5 mg/L of 6-benzyladenine (BA). The effect of the medium and different treatments of LED lights (blue (BL), red (RL), white (WL), and a combination of red and blue (R:BL; 7:3)) on R. carthamoides shoot growth and its biosynthetic potential was observed. Medium type and the duration of LED light exposure did not affect the proliferation rate of shoots, but they altered the shoot morphology and specialized metabolite accumulation. The liquid medium and BL light were the most beneficial for the caffeoylquinic acid derivatives (CQAs) production, shoot growth, and biomass increment. The liquid medium and BL light enhanced the content of the sum of all identified CQAs (6 mg/g DW) about three-fold compared to WL light and control, fluorescent lamps. HPLC-UV analysis confirmed that chlorogenic acid (5-CQA) was the primary compound in shoot extracts regardless of the type of culture and the light conditions (1.19-3.25 mg/g DW), with the highest level under R:BL light. BL and RL lights were equally effective. The abundant component was also 3,5-di-O-caffeoylquinic acid, accompanied by 4,5-di-O-caffeoylquinic acid, a tentatively identified dicaffeoylquinic acid derivative, and a tricaffeoylquinic acid derivative 2, the contents of which depended on the LED light conditions.

Enhanced antioxidant activity in Curcuma caesia Roxb. microrhizomes treated with silver nanoparticles

Curcuma caesia Roxb. is a highly valuable, endangered herb of therapeutic importance that resides in their rhizomes. In the present investigation, the effect of ½ strength liquid Murashige and Skoog (MS) medium supplemented with 1 mg/l Indole-3-butyric acid (IBA) and different sucrose concentrations (1.5%, 3%, 6%, 9%, or 12%) was studied on microrhizomes induction of C. caesia. The shoot length, root length and microrhizomes dry weight of C. caesia decreased significantly at 6% sucrose and above. When compared to the control (1.5% sucrose), the current water content significantly decreased at 6% sucrose. The optimum concentration for in vitro microrhizomes induction in C. caesia was 6% sucrose. Therefore for further experiments, the 6% sucrose was used. We also studied the effect of silver nanoparticles (AgNP) on microrhizome induction and antioxidant activity in C. caesia cultures. Field-grown C. caesia rhizomes extract was used in the green synthesis of AgNP. The synthesized AgNP was further characterized through scanning electron microscopy and X-ray diffraction. The AgNP, ranging from 0, 0.025, 0.05, 0.075 or 0.1 mg/l was supplemented in ½ strength liquid MS medium with 6% sucrose and 1 mg/l IBA. The MS medium with 0.05 mg/l AgNP found with significant morphological changes in C. caesia cultures (root number, root length and microrhizomes fresh weight). For the total phenolic and total terpenoids content estimation as well as for antioxidant activity analysis, the extracts of un-treated cultures (6% sucrose + 1 mg/l IBA, without AgNP), AgNP treated cultures (6% sucrose + 1 mg/l IBA with 0.025 and 0.05 mg/l AgNP) was used. The 0.025 and 0.05 mg/l AgNP enhanced the phenolic and terpenoid content in the cultures compared to the field-grown mother plant. The antioxidant activity of the cultures treated with AgNP also increased compared to un-treated cultures and field-grown mother plant. The Gas Chromatography-Mass Spectrometry (GC-MS) analysis revealed that the extract treated with 0.05 mg/l AgNP had increased production of monoterpene (camphor) and sesquiterpenes (β-elemenone and curcumenone). These increased terpenes could be responsible for the enhanced antioxidant activity of C. caesia cultures.

In vitro toxicity evaluation in A549 cells of diesel particulate matter from two different particle sampling systems and several resuspension media.

In urban areas, inhalation of fine particles from combustion sources such as diesel engines causes adverse health effects. For toxicity testing, a substantial amount of particulate matter (PM) is needed. Conventional sampling involves collection of PM onto substrates by filtration or inertial impaction. A major drawback to those methodologies is that the extraction process can modify the collected particles and alter their chemical composition. Moreover, prior to toxicity testing, PM samples need to be resuspended, which can alter the PM sample even further. Lastly, the choice of the resuspension medium may also impact the detected toxicological responses. In this study, we compared the toxicity profile of PM obtained from two alternative sampling systems, using in vitro toxicity assays. One system makes use of condensational growth before collection in water in an impinger - BioSampler (CG-BioSampler), and the other, a Dekati® Gravimetric Impactor (DGI), is based on inertial impaction. In addition, various methods for resuspension of DGI collected PM were compared. Tested endpoints included cytotoxicity, formation of cellular reactive oxygen species, and genotoxicity. The alternative collection and suspension methods affected different toxicological endpoints. The water/dimethyl sulfoxide mixture and cell culture medium resuspended particles, along with the CG-BioSampler sample, produced the strongest responses. The water resuspended sample from the DGI appeared least toxic. CG-BioSampler collected PM caused a clear increased response in apoptotic cell death. We conclude that the CG-BioSampler PM sampler is a promising alternative to inertial impaction sampling.

Antibacterial and antiviral PA6-AgNPs microfibers for application as a filter element in facial respirators

Polymeric microfibers are very interesting materials that can be associated with other nanomaterials aiming to obtain specific properties and be used in a wide range of applications. In this study, we prepared different formulations of polyamide 6 (PA6) containing silver nanoparticles (AgNPs) and produced microfibers by solution blow spinning technique for its use as a filter element in a face respirator. The obtained samples were then characterized by field emission gun-scanning electron microscopy (FEG-SEM), energy dispersion spectroscopy (EDS), ultraviolet–visible diffuse reflectance spectroscopy (UV–Vis DRS), water contact angle (WCA), thermogravimetric analysis (TGA), and respirability and antibacterial, antiviral and cytotoxicity assays. In general, the microfibers were well dispersed and the AgNPs were evenly distributed throughout the samples, reflecting a hydrophilic character and good thermal stability, with a maximum weight loss of 2.9 % attributed to the evaporation of water molecules. The sample produced with a concentration of 10 mmol/L of silver nitrate presented acceptable levels of resistance to respiration. Concerning the microbiological analyses, the results showed that samples evidenced antibacterial effect against Escherichia coli and Staphylococcus aureus, forming inhibition halos of up to 4 mm in disk diffusion assays and inhibiting bacterial growth in liquid medium assays, as well as antiviral effect against betacoronavirus MHV-3, promoting a reduction of up to 99.9 % of viral particles. Moreover, the samples presented cytotoxicity on the first and second days, whereas on the seventh day some of the extracts did not show cytotoxic activity, indicating that the cells adapted to the culture medium. Considering the data set and the simple process of obtaining the microfibers, it was possible to conclude that this material can be applied as a filter element in a face respirator as well as in a variety of products with antibacterial and antiviral purposes.

Growth of Nordic container forest tree seedlings in some peatless and peat-reduced growing media

AbstractCarbon emissions and environmental concerns have led to the aspiration to reduce peat extraction and its use as a growing medium (GM). In Nordic Forest tree seedling production, Sphagnum peat has been almost exclusively used as a GM in seedling containers due to its good properties and availability. This study examined the feasibility of several peat-reduced and peat-free GM in container tree seedling production of the key tree species in Nordic forestry (Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L. Karst.) and silver birch (Betula pendula Roth) as well as Russian larch (Larix archangelica P. Lawson & C. Lawson ex Trautv.) and common alder (Alnus glutinosa (L.) Gaertn.). Pure or mixed GM, consisting of low-humified Sphagnum peat (pure as a control), harvested Sphagnum moss, wood fiber, cow manure digestate from a biogas plant, and a common reed compost were tested. Seedlings were grown in controlled conditions in greenhouse experiments and also in larger-scale commercial tree nurseries. Peat-reduced media containing peat of at least 50 vol% provided growth that is similar to pure Sphagnum peat for the tested species and container types. All the studied alternative media can yield marketable seedlings, although commonly of reduced size and requiring special adjustments in growing management. The studied media have a potential to reduce or replace peat in seedling production, but adjustments of their physical and chemical properties, as well as of seedling fertigation and management procedures, are required. The economic feasibility and environmental sustainability of these GM, as well as the outplanting success of seedlings grown in these media, remain to be studied.

Detailed analysis of agro-industrial byproducts/wastes to enable efficient sorting for various agro-industrial applications

Agriculture-based industries generate huge amounts of byproducts/wastes every year, which are not exploited or disposed efficiently posing an environmental problem with implications to human and animal health. Finding strategies to increase the recycling of agro-industrial byproducts/wastes (AIBWs) is a primary objective of the current study. A thorough examination of AIBWs in conjunction with experimental research is proposed to facilitate sorting for various agro-industrial applications and consequently increasing byproduct/waste utilization. Accordingly, two sustainable, locally available sources of AIBWs, namely, wheat bran (WB) and garlic straw and peels (GSP) were studied in detail including content and composition of proteins, phytohormones and nutritional elements, as well as the effect of AIBW extracts on plant and microbial growth. Hundreds of proteins were recovered from AIBW mainly from WBs, including chaperons, metabolite and protein modifying enzymes, and antimicrobial proteins. In-gel assays showed that WB and GSP possess high protease and nuclease activities. Conspicuously, phytohormone analysis of AIBWs revealed the presence of high levels of strigolactones, stimulants of seed germination of root parasitic weeds, as well as indole acetic acid (IAA) and abscisic acid (ABA). Garlic straw extract strongly inhibited germination of the weed Amaranthus palmeri but not of Abutilon theophrasti and all examined AIBWs significantly affected post-germination growth. Bacterial growth was strongly inhibited by garlic straw, but enhanced by WBs, which can be used at least partly as a bacterial growth medium. Thus, an in-depth examination of AIBW characteristics will enable appropriate sorting for diverse agro-industrial applications, which will increase their utilization and consequently their economic value.

Optical tweezers for probing the interactions of ZnO and Ag nanoparticles with E. coli.

The antibacterial effect of nanoparticles is mainly studied on the ensembles of the bacteria. In contrast, the optical tweezer technique allows the investigation of similar effects on individual bacterium. E. coli is a self-propelled micro-swimmer and ATP-driven active microorganism. In this work, an optical tweezer is employed to examine the mechanical properties of E. coli incubated with ZnO and Ag nanoparticles (NP) in the growth medium. ZnO and Ag NP with a concentration of 10µg/ml were dispersed in growth medium during active log-growth phase of E. coli. This E. coli-NP incubation is further continued for 12h. The E. coli after incubation for 2h, 6h and 12h were separately studied by the optical tweezer for their mechanical property. The IR laser (λ = 975 nm; power = 100mW) was used for trapping the individual cells and estimated trapping force, trapping stiffness and corner frequency. The optical trapping force on E. coli incubated in nanoparticle suspension shows linear decreases with incubation time. This work brings the importance of optical trapping force measurement in probing the antibacterial stress due to nanoparticles on the individual bacterium.

Use of spectroscopic process analytical technology for rapid quality evaluation during preparation of CHO cell culture media.

Media preparation parameters contribute significantly to media quality, cell culture performance, productivity, and product quality. Establishing proper media preparation procedures is critical for ensuring a robust CHO cell culture process. Process analytical technology (PAT) enables unique ways to quantify assessments and improve media quality. Here, cell culture media were prepared under a wide range of temperatures (40-80°C) and pH (7.6-10.0). Media quality profiles were compared using three real-time PATs: Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, and excitation-emission matrix (EEM) spectroscopy. FTIR and Raman spectroscopies identified shifts in media quality under high preparation temperature (80°C) and at differing preparation pH which negatively impacted monoclonal antibody (mAb) production. In fed-batch processes for production of three different mAbs, viable cell density (VCD) and cell viability were mostly unaffected under all media preparation temperatures, while titer and cell specific productivity of mAb decreased when cultured in basal and feed media prepared at 80°C. High feed preparation pH alone was tolerated but cell growth and productivity profiles deviated from the control condition. Further, charge variants (main, acidic, basic species) and glycosylation (G0F, afucosylation, and high mannose) were examined. Statistically significant differences were observed for one or more of these quality attributes with any shifts in media preparation. In this study, we demonstrated strong associations between media preparation conditions and cell growth, productivity, and product quality. The rapid evaluation of media by PAT implementation enabled more comprehensive understanding of different parameters on media quality and consequential effects on CHO cell culture.

Adipose Stem Cell Response to Borophosphate Bioactive Glass

Silicate and borate bioactive glasses have been reported to create alkaline conditions by rapidly releasing ions when reacting in aqueous solution. At certain levels, this alkaline solution can negatively affect cell viability. Adding phosphate ions to the glass composition can control the degradation rate of bioactive glasses and create a neutral pH environment. This study evaluated a series of borophosphate bioactive glasses (BPBGs) with nominal molar compositions 16Na2O-24CaO-xB2O3-(60-x)P2O5, where x = 0, 40, or 60. The phosphate (X0) glass (PBG) produced an acidic solution when dissolved in water; the borate (X60) glass (BBG) produced an alkaline solution, and the BPBG glass produced a pH-neutral solution. These three glasses were evaluated using adipose stem cells (ASCs), a cell population known for their therapeutic abilities. The effects of each glass on the pH of cell culture, ions released during degradation, and on ASC functions, including viability, migration, angiogenic ability, differentiation, and protein secretions, were evaluated. The X40 BPBG created a physiologically neutral pH in cell culture media after 24 h. The X0 phosphate glass promoted ASC migration, while the highly alkaline X60 borate increased the angiogenic ability of ASCs. These results indicate that BPBG can be used safely in cell culture studies and customized for specific biomedical applications.

Features of obtaining composite material from hydrophobic clay with antimicrobic properties

A method for obtaining a nanocomposite from hydrophobic clays with bactericidal properties is considered, which plays the role of a drug matrix intercalated agar-agar. Such nanocomposite materials are increasingly used in medicine as matrices for medicines and vitamins using their adsorption properties and long-term exposure. It was established using TEM analysis that halloysite particles from Beloye Glinische deposit are nanoscale and have a cylindrical shape with a length from 200 nm to 1000 nm and a diameter of nanoparticles from 50 nm to 80 nm. The first stage of the bionanocomposites manufacturing process was the treatment of halloysite nanoparticles with silver ions to impart antimicrobial properties, and hydrophobization with a cationic surfactant was carried out at the next stage. It was established by the X-ray diffraction method that the interlayer space of HNT has been expanded from 9.998 Å to 17.5 Å on the result of the cationic adsorption on the HNT. FTIR spectroscopy also proved the adsorption of surfactant molecules on halloysite by the presence of an appropriate absorption band. The adsorption of silver on a nanotube made of halloysite was revealed by the method of energy-dispersive X-ray spectroscopy. Antimicrobial properties of silver-treated and organophilic halloysite have been established and proved by in vitro analyses in microbiological laboratories about Escherichia coli. Hydrophobic samples of these organophilic clays had edge angles higher than 90° and this proves that all samples are hydrophobic. The resulting organophilic clays were intercalated into an agar-agar matrix and were thrown into a solution of calcium chloride, which gave them stability in a liquid medium. It has been practically established that the most optimal bionanocomposite microsphere is a 50% ratio of organohalloysite and agar-agar.

Observations of root hair patterning in soils: Insights from synchrotron-based X-ray computed microtomography

Abstract Background And Aims Root hair emergence is affected by heterogeneities in water availability in the growth medium. Root hairs preferentially emerge into air, whereas their emergence into water is inhibited. Yet, these results were based either on destructive methods or on roots grown on an agar-air interface. Additionally, there is a lack of knowledge about the spatial distribution of root hairs as hairs elongate radially across the rhizosphere. Therefore, root hair growth in soils remains largely unexplored. Methods Maize (Zea Mays L.) plants were grown in microcosms which were scanned with a synchrotron-based X-ray $$\mu $$ μ CT. The distribution of root hairs along the root epidermis and radially across the rhizosphere (i.e. as function of distance from the root epidermis) was analysed using spatial point pattern analysis. Results While hairs emerged randomly in air-filled pores, their emergence was inhibited where the root was in contact with the soil matrix. As hairs elongated radially into the soil, they were preferentially located in the close proximity of soil particles. In maize, we rarely observed root hairs penetrating into soil aggregates. Conclusion We conclude that in maize, root hairs grow in air-filled pores at the root-soil interface, where the flow of nutrients and water is impeded. Across the rhizosphere, hairs establish contact to the soil by growing in the proximity to soil particles. The effect of hairs on uptake processes, plant anchorage and rhizosheath formation might be limited (in maize) as they hardly penetrate into soil aggregates.

Complex nitrogen sources from agro-industrial byproducts: impact on production, multi-stress tolerance, virulence, and quality of Beauveria bassiana blastospores.

Biological control through entomopathogenic fungi provides essential ecological services in the integrated management of agricultural pests. In the context of submerged liquid fermentation, the nutritional composition significantly influences the ecological fitness, virulence and quality of these fungi. This study specifically explores the impact of various complex organic nitrogen sources derived from agro-industrial byproducts on the submerged liquid fermentation of Beauveria bassiana, a versatile entomopathogenic fungus known for producing hydrophilic yeast-like blastospores. Notably, manipulating the nitrogen source during submerged cultivation can influence the quality, fitness, and performance of blastospores. This research identifies cottonseed flour as the optimal low-cost nitrogen source, contributing to increased production yields, enhanced multi-stress tolerance, heightened virulence with extended shelf life and long-term bioactivity. These findings deepen our understanding of the critical role of nitrogen compound selection in liquid media formulation, facilitating the production of ecologically fit and virulent blastospores for more effective pest biocontrol programs.

Instantaneous thermometry imaging using two-photon laser-induced fluorescence.

Measuring temperature in complex two-phase flows is crucial for understanding the dynamics of heat and mass transfer. In this Letter, we introduce a novel, to the best of our knowledge, optical approach based on the combination of two-photon laser-induced fluorescence (2p-LIF) imaging and two-color laser-induced fluorescence (2CLIF) for instantaneous temperature mapping of complex liquid media. Using Kiton Red (KR) and Rhodamine 560 (R560), a temperature sensitivity of 1.54%/∘C has been achieved over a range of 17-60°C. The monitoring of two-dimensional transient temperature dynamics in the heating and degassing of water shows the efficiency of the 2p-2CLIF. This new approach contributes to the toolkit of optical temperature measurement techniques, providing a robust solution for studying transient scattering media and high-speed two-phase flows.

Integration of biocompatible hydrogen evolution catalyst developed from metal-mix solutions with microbial electrosynthesis

Microbial conversion of CO2 to multi-carbon compounds such as acetate and butyrate is a promising valorisation technique. For those reactions, the electrochemical supply of hydrogen to the biocatalyst is a viable approach. Earlier we have shown that trace metals from microbial growth media spontaneously form in situ electro-catalysts for hydrogen evolution. Here, we show biocompatibility with the successful integration of such metal mix-based HER catalyst for immediate start-up of microbial acetogenesis (CO2 to acetate). Also, n-butyrate formation started fast (after twenty days). Hydrogen was always produced in excess, although productivity decreased over the 36 to 50 days, possibly due to metal leaching from the cathode. The HER catalyst boosted microbial productivity in a two-step microbial community bioprocess: acetogenesis by a BRH-c20a strain and acetate elongation to n-butyrate by Clostridium sensu stricto 12 (related) species. These findings provide new routes to integrate electro-catalysts and micro-organisms showing respectively bio and electrochemical compatibility.

Determining Eastern Red Cedar Biochar Soilless-Media Supplementation Rates for Potted Geranium and Petunia Production

The use of biochar in soilless media is becoming more common in greenhouse production. This study was conducted to evaluate Eastern red cedar biochar as a soilless-media supplement for the growth of geranium (Pelargonium graveolens L.) and petunia (Petunia sp. J.) as potted plants in greenhousese. Eastern red cedar biomass was produced at three different temperature ranges 300–350 °C, 400–450 °C, and 500–550 °C and applied at 15%, 30%, 45%, and 60% v/v to a soilless media plus a control. Additionally, Eastern red cedar (ERC) bark was also applied at 15%, 30%, 45%, and 60% v/v to a soilless media. The growth characteristics of the plants along with the physical and nutrient properties of the growth media were recorded. For physical properties, 100% soilless media had the greatest bulk density, 60% biochar at 400–450 °C showed the greatest total porosity, and 60% ERC bark showed the greatest air porosity. For geranium, 15% biochar at 500–550 °C showed the greatest height, water use efficiency, and shoot dry weight, while 15% biochar at 300–350 °C showed the greatest width. The greatest number of flowers was at 45% biochar at 500–550 °C. For petunia, 15% biochar at 300–350 °C showed the greatest height, and 15% biochar at 500–550 °C showed the greatest width. The greatest number of flowers and flower diameter was achieved with 100% soilless media. The 15% biochar at 500–550 °C had the greatest shoot dry weight and water use efficiency, and 60% biochar at 400–450 °C had the greatest root dry weight. Biochar treatment outperforms the ERC bark treatment for both species. Within biochar treatment, 15% biochar outperforms dry biomass, while for flowering, 100% soilless media performs best for petunia, and biochar performs best at less than 45% for geranium.

A Pilot Study of Aerosolization of InfectiousMurine Norovirus in an Experimental Setup.

Human norovirus is transmitted mainly via the faecal-oral route, but norovirus disease outbreaks have been reported in which airborne transmission has been suggested as the only explanation. We used murine norovirus (MNV) as a surrogate for human norovirus to determine the aerosolization of infectious norovirus in an experimental setup. A 3-l air chamber system was used for aerosolization of MNV. Virus in solution (6 log10 TCID50/ml) was introduced into the nebulizer for generating aerosols and a RAW 264.7 cell dish without a lid was placed in the air chamber. Cell culture medium samples were taken from the dishes after the aerosol exposure time of 30 or 90min, and the dishes were placed in a 37°C, 5% CO2 incubator and inspected with a light microscope for viral cytopathic effects (CPEs). We determined both the infectious MNV TCID50 titre and used an RT-qPCR assay. During the experiments, virus infectivity remained stable for 30 and 90min in the MNV solution in the nebulizer. Infectious MNV TCID50 values/ml of 2.89 ± 0.29 and 3.20 ± 0.49 log10 were measured in the chamber in RAW 264.7 cell dish media after the 30-min and 90-min exposure, respectively. The MNV RNA loads were 6.20 ± 0.24 and 6.93 ± 1.02 log10 genome copies/ml, respectively. Later, a typical MNV CPE appeared in the aerosol-exposed RAW cell dishes. We demonstrated that MNV was aerosolized and that it remained infectious in the experimental setup used. Further studies required for understanding the behaviour of MNV in aerosols can thus be performed.