Growth Medium Research Articles

Functional and biochemical characterisation of remote homologues of type IV pili proteins PilN and PilO in Helicobacter pylori.

Helicobacter pylori encodes homologues of PilM, PilN and PilO from bacteria with Type IV pili, where these proteins form a pilus alignment complex. Inactivation of pilO changes H. pylori motility in semi-solid media, suggesting a link to the chemosensory pathways or flagellar motor. Here, we showed that mutation of the pilO or pilN gene in H. pylori strain SS1 reduced the mean linear swimming speed in liquid media, implicating PilO and PilN in the function, or regulation of, the flagellar motor. We also demonstrated that the soluble variants of H. pylori PilN and PilO share common biochemical properties with their Type IV pili counterparts which suggests their adapted function in the bacterial flagellar motor may be similar to that in the Type IV pili.

Enhancing the Activity of a Carbon Nitride Photocatalyst by Constructing a Triazine-Heptazine Homojunction.

Establishing homojunctions at the molecular level between different but physicochemically similar phases belonging to the same family of materials is an effective approach to promoting the photocatalytic activity of polymeric carbon nitride (CN) materials. Here, we prepared a CN material with a uniform distribution of homojunctions by combining two synthetic strategies: supramolecular assemblies as the precursor and molten salt as the medium. We designed porous CN rods with triazine-heptazine homojunctions (THCNs) using a melem supramolecular aggregate (Me) and melamine as the precursors and a KCl/LiBr salt mixture as the liquid reaction medium. The triazine/heptazine ratio is controlled by varying the relative amounts of the chosen precursors, and the molten salt treatment enhances the structural order of the interplanar packing units for the THCN skeleton, leading to rapid charge migration. The resulting built-in electric field induced by the triazine-heptazine homojunction enhances photogenerated charge separation; the optimal THCN catalyst exhibits an excellent H2 evolution rate via photocatalytic water splitting, which is ∼24 times as high as that of reference bulk CN, with long-term stability.

Fluorinated tags to study protein conformation and interactions using19F NMR.

The incorporation of fluorine atoms into a biomacromolecule provides a background-free and environmentally sensitive reporter of structure, conformation and interactions using19F NMR. There are several methods to introduce the19F reporter - either by synthetic incorporationviasolid phase peptide synthesis; by suppressing the incorporation or biosynthesis of a natural amino acid and supplementing the growth media with a fluorinated counterpart during protein expression; and by genetic code expansion to add new amino acids to the amino acid alphabet. This review aims to discuss progress in the field of introducing fluorinated handles into biomolecules for NMR studies by post-translational bioconjugation or 'fluorine-tagging'. We will discuss the range of chemical tagging 'warheads' that have been used, explore the applications of fluorine tags, discuss ways to enhance reporter sensitivity and how the signal to noiseratioscan be boosted. Finally, we consider some key challenges of the field and offer some ideas for future directions.

Identification of Biotransformation Products of T-2 Toxin in HepG2 Cells Using LC-Q-TOF MS

The T-2 toxin (T-2) is a type A trichothecene found in cereals. The formation of metabolites is a frequent cause of mycotoxin-induced toxicity. In this work, the conversion of T-2 during biotransformation reactions in HepG2 cells was evaluated. For this, HepG2 cells were exposed to 30 (IC50/2) and 60 (IC50) nM of T-2 for 0, 1, 2, 3, 6, 8 and 24 h, and the concentrations of T-2 and its metabolites HT-2, T2-triol, T2-tetraol and neosolaniol were determined in both the cell fraction and culture medium through liquid chromatography coupled to high-resolution mass spectrometry–time of flight (LC-Q-TOF MS). Results showed a fast metabolization of T-2 (>90%) during the first 2 h, with HT-2 as its main (>95%) biotransformation product. The cell fraction showed higher levels (p < 0.05) of HT-2 (39.9 ± 2.1 nM) compared to the culture medium (12.53 ± 2.4 nM). This trend was also observed for the identified metabolites. T2-triol reached its maximum concentration (1.7 ± 0.4 nM) at 2 h, and at later times a time-dependent increase in the T2-tetraol and neosolaniol concentrations was observed. The identification of T-2 metabolites shows the need to continue combined toxicity studies of mycotoxins for a correct risk characterization of these natural contaminants.

Essential oil of Lippia multiflora Moldenke Flowers Quenches Pseudomonas aeruginosa PAO1 Biofilm Formation and Motilities

Bacteria use different types of motilities in order to colonize and adapt to new environments. These motilities also play an important role in the formation of biofilm, allowing bacteria to develop resistance to antibiotics and host’s immune systems. The objective of this study was to evaluate the ability of essential oils of Lippia multiflora flowers to inhibit biofilm formation and motility in Pseudomonas aeruginosa PAO1. The capacity of essential oil of Lippia multiflora flowers to inhibit biofilm formation in Pseudomonas aeruginosa was evaluated spectrophotometrically by using the crystal violet method. The property of the essential oil to inhibit different types of motilities such as swimming, swarming and twitching was further evaluated by measuring the diameters of bacterial migration on liquid or semi-liquid Luria Bertani agar medium. The essential oil exhibited good anti-biofilm activity in Pseudomonas aeruginosa. At a concentration of 1%, essential oil presented a degree of biofilm inhibition similar to that of salicylic acid used as a reference (P > 0.05). In addition, the essential oil significantly inhibited swarming, twitching and swimming in Pseudomonas aeruginosa compared to the control (P < 0.001). The inhibition of biofilm formation as well as that of bacterial motility increases with the concentration of the essential oil. The essential oil of Lippia multiflora flowers possesses an anti-bacterial potential to fight against multi-resistant bacteria.

The Transformative Role of 3D Culture Models in Triple-Negative Breast Cancer Research

Advancements in cell culturing techniques have allowed the development of three-dimensional (3D) cell culture models sourced directly from patients’ tissues and tumors, faithfully replicating the native tissue environment. These models provide a more clinically relevant platform for studying disease progression and treatment responses compared to traditional two-dimensional (2D) models. Patient-derived organoids (PDOs) and patient-derived xenograft organoids (PDXOs) emerge as innovative 3D cancer models capable of accurately mimicking the tumor’s unique features, enhancing our understanding of tumor complexities, and predicting clinical outcomes. Triple-negative breast cancer (TNBC) poses significant clinical challenges due to its aggressive nature, propensity for early metastasis, and limited treatment options. TNBC PDOs and PDXOs have significantly contributed to the comprehension of TNBC, providing novel insights into its underlying mechanism and identifying potential therapeutic targets. This review explores the transformative role of various 3D cancer models in elucidating TNBC pathogenesis and guiding novel therapeutic strategies. It also provides an overview of diverse 3D cell culture models, derived from cell lines and tumors, highlighting their advantages and culturing challenges. Finally, it delves into live-cell imaging techniques, endpoint assays, and alternative cell culture media and methodologies, such as scaffold-free and scaffold-based systems, essential for advancing 3D cancer model research and development.

Reduction of Ferric Chloride in Yeast Growth Media, by Sugars and Aluminum

Iron compounds can be used in antimicrobial applications by exploiting the toxicity of divalent iron to living organisms due to the Fenton reaction. In this study, the growth inhibitory effects of ferrous sulfate FeSO4·7H2O and ferric chloride FeCl3·6H2O were observed on Metschnikowia clade and Saccharomyces cerevisiae yeast cells. The relatively high amount of reduced Fe3+ to Fe2+ in the growth medium determined by Mössbauer spectroscopy may contribute to the antimicrobial activity of ferric chloride. In order to test the reducing ability of sugars in the growth media of yeasts, the reaction of ferric chloride FeCl3·6H2O with sugars was investigated. In mixtures of FeCl3·6H2O and fructose, approximately two thirds of Fe3+ can be reduced to Fe2+. When the mixture of FeCl3·6H2O and fructose is placed on the surface of aluminum foil, an iron film is formed on the surface of the aluminum due to the reduction by both fructose and aluminum. The relative amount of Fe3+ which was reduced to Fe0 reached 68%.

Pristionchus seladoniae n. sp. (Diplogastridae) isolated from a eusocial soil-dwelling bee, Halictus (Seladonia) aerarius, in Nagano, Japan

Summary A new species of Pristionchus was isolated from a soil-dwelling bee, Halictus (Seladonia) aerarius, collected from Sugadaira, Nagano, Japan. The nematode was successfully cultured on nematode growth medium agar previously inoculated with the Escherichia coli strain OP50; however, it did not propagate well. Typologically, the new species is similar to other Pristionchus belonging to the maupasi, pacificus and lheritieri groups in the stomatal structure of stenostomatous form. However, the species is characterised by the relatively short, conical tail of the female and the arrangement of male genital papillae in which the second- and third-paired papillae are almost at the same level and one of these two are directed laterally. Phylogenetically, the nematode belongs to the maupasi group, the ‘American clade’ within the genus, and is separable from the other species in the group. Biologically, the species has several interesting characters: it is seemingly native to Japan, regardless of its phylogenetic group; it is in tight and specific phoretic association with a eusocial bee; it lacks a eurystomatous form (or this form occurs rarely) under cultured conditions; and it shows characteristic clumping behaviour on culture media. The new species is taxonomically described herein as Pristionchus seladoniae n. sp.

Discovery of new eremophilanes from the marine-derived fungus Emericellopsis maritima BC17 by culture conditions changes: evaluation of cytotoxic and antimicrobial activities

In our previous studies, the marine-derived fungus Emericellopsis maritima BC17 was found to produce new eremophilane-type sesquiterpenoids on solid media. In order to explore its potential to produce more metabolites, E. maritima BC17 was subjected to a one strain-many compounds (OSMAC) analysis leading to the discovery of three new eremophilanes (1-3) and fourteen known derivatives (4-17) in the liquid media Czapek Dox and PDB. Their structures were established by extensive analyses of the 1D and 2D NMR, and HRESIMS data, as well as ECD data for the assignment of their absolute configurations. Antitumoral and antimicrobial activities of the isolated metabolites 1, 3, 11, and 15 were investigated. PR toxin 3-deacetyl (15) exhibited cytotoxic activity against HepG2, MCF-7, A549, A2058 and Mia PaCa-2 human cancer cell lines with IC50 values ranging from 2.5 to 14.7 µM. In addition, 15 exhibited selective activity against methicillin-sensitive Staphylococcus aureus ATCC29213 at the highest concentration tested of 128 µg/mL.

Glucose-induced RYBP suppresses tumor cell aerobic glycolysis and migration

RYBP (Ring 1 and YY1 binding protein) has been frequently reported to play an important role during body development, stem cell differentiation, apoptosis and tumorigenesis, but whether RYBP carries out additional functions remains mysterious. Here, we demonstrated that RYBP protein levels elevate with increasing glucose concentration in cell culture medium in human tumorigenic cell lines, but an opposite trend was observed in non-tumorigenic cells. Mechanistic exploration disclosed that glucose inhibits polyubiquitination and proteasomal degradation, leading to RYBP stabilization in tumor cells. Further study showed that RYBP inhibits the glycolysis of tumor cells, as both extracellular acidification rate (ECAR) and lactate production increase when RYBP is knocked down, and decrease when RYBP is over-expressed, and this effect is unrelated to the glucose uptake ability of tumor cells. The functional study showed that RYBP is involved in the regulation of glucose on tumor cell migration. Compared to low glucose culture and their wildtypes, high glucose significantly enhanced tumor cell migration in RYBP knockdown or knockout tumor cells. Taken together, our current study uncovered a previously unknown function of RYBP in tumor metabolism, and this finding will enhance the exploration of the interplay between RYBP and nutrients during tumor cell metabolic reprogramming.

In Vitro Cytotoxic and Inflammatory Response of Gingival Fibroblasts and Oral Mucosal Keratinocytes to 3D Printed Oral Devices

The purpose of this study was to examine the biocompatibility of 3D printed materials used for additive manufacturing of rigid and flexible oral devices. Oral splints were produced and finished from six printable resins (pairs of rigid/flexible materials: KeySplint Hard [KR], KeySplint Soft [KF], V-Print Splint [VR], V-Print Splint Comfort [VF], NextDent Ortho Rigid [NR], NextDent Ortho Flex [NF]), and two types of PMMA blocks for subtractive manufacturing (Tizian Blank PMMA [TR], Tizian Flex Splint Comfort [TF]) as controls. The specimens were eluted in a cell culture medium for 7d. Human gingival fibroblasts (hGF-1) and human oral mucosal keratinocytes (hOK) were exposed to the eluates for 24 h. Cell viability, glutathione levels, apoptosis, necrosis, the cellular inflammatory response (IL-6 and PGE2 secretion), and cell morphology were assessed. All eluates led to a slight reduction of hGF-1 viability and intracellular glutathione levels. The strongest cytotoxic response of hGF-1 was observed with KF, NF, and NR eluates (p < 0.05 compared to unexposed cells). Viability, caspase-3/7 activity, necrosis levels, and IL-6/PGE2 secretion of hOK were barely affected by the materials. All materials showed an overall acceptable biocompatibility. hOK appeared to be more resilient to noxious agents than hGF-1 in vitro. There is insufficient evidence to generalize that flexible materials are more cytotoxic than rigid materials. From a biological point of view, 3D printing seems to be a viable alternative to milling for producing oral devices.

FEM Modeling Strategies: Application to Mechanical and Dielectric Sensitivities of Love Wave Devices in Liquid Medium

This paper presents an extended work on the Finite Element Method (FEM) simulation of Love Wave (LW) sensors in a liquid medium. Two models are proposed to simulate the multiphysical response of the sensor. Both are extensively described in terms of principle, composition and behavior, making their applications easily reproducible by the sensor community. The first model is a Representative Volume Element (RVE) simulating the transducer and the second focuses on the sensor’s longitudinal (OXZ) cut which simulates the multiphysical responses of the device. Sensitivity of the LW device to variations in the rheological and dielectric properties of liquids is estimated and then compared to a large set of measurements issued from LW sensors presenting different technological characteristics. This integral approach allows for a deeper insight into the multiphysical behavior of the LW sensor. This article also explores the advantages and drawbacks of each model. Both are in good accordance with the measurements and could be used for various applications, for which a non-exhaustive list is proposed in the conclusion.

Isolation, characterization and optimization of oleaginous Providencia vermicola as a feedstock for biodiesel production using Response Surface Methodology

Oleaginous organisms accrue more than twenty percent of their biomass as lipids and hence are promising feedstocks for biodiesel production. In this study, lipid accumulating bacteria were isolated from diesel-contaminated soils and screened with Sudan black B stain. The most oleaginous was done using 16s rRNA gene sequencing. Lipid production was initially optimized based on media, nitrogen source, pH and temperature. Response surface methodology (RSM) was then employed for the enhancement of lipid weight and content. Obtained lipid was converted to biodiesel using direct transesterification, and both lipid and biodiesel were characterized using FTIR. A total of thirteen bacteria were isolated and the most prominent lipid producer was identified as Providencia vermicola with lab number BA6. Preliminary optimization studies revealed optimum lipid production when nutrient broth and acetic acid served as carbon source; KNO3 as nitrogen source, pH 7.0 and 30 °C. Optimization using RSM resulted in a 5.1% and 74.1% increase in the biomass and lipid content of BA6 respectively. FTIR analyses confirmed the presence of functional groups characteristic of lipids and biodiesel. P. vermicola is a novel oleaginous organism that represents a promising feedstock for biodiesel production. HIGHLIGHTS The bacterium designated as BA6 identified as Providencia vermicola has the highest lipid contents of the oleaginous bacteria isolated. It accumulates lipids up to 47.73 % of its biomass The percentage lipids accumulation increased to about 74 % when RSM was used. Providencia vermicola is being reported as an oleaginous organism for the first time.

A promotion strategy of enhancing the mercury removal in Shewanella oneidensis MR-1 based on the mercury absorption and electronic consumption via mer operon

Shewanella oneidensis (S. oneidensis) bacteria have bioremediation capabilities for various heavy metals, however, their repertoire of mercury-removal proteins is limited, restricting their effectiveness in mercury remediation. In this study, the integration of an exogenous mer operon into S. oneidensis expanded the range of mercury-removal proteins, significantly boosting both mercury tolerance and removal efficiency. The engineering bacteria (MR-mer) exhibited growth in a 180 mg/L Hg2+ solution, showing a 40% increase in tolerance over S. oneidensis. In a liquid medium with 50 mg/L Hg2+, the MR-mer strain achieved 73% mercury removal efficiency, outperforming the original strain by 50%, and facilitated Hg0 formation on the cell membrane. Extensive analysis of transmembrane structures and Fourier analysis revealed that mer operon proteins might target the cell membrane, modifying its functional group contents to enhance mercury adsorption. Additionally, the absence of the key protein OmcA in the electron transport chain led to a 30% reduction in Hg2+ removal capacity. This suggests that S. oneidensis transfers electrons to the cell surface through this chain, providing electrons for Hg2+ reduction. In conclusion, the mer operon, targeting the cell membrane in MR-mer strain, synergizes with the electron transport chain to markedly elevate Hg2+ removal capability. This approach not only augments Shewanella's mercury biodegradation capacity, but also offers novel perspectives for microbial heavy metal pollutant removal.

The extended transmission of cold atmospheric plasma-induced anticancer effects between cells

Abstract The application of cold atmospheric plasma (CAP) in cancer therapy has recently received extensive attention. However, researchers have mainly studied the effects of CAP on plasma-irradiated cancer cells and have not determined whether CAP affects surrounding or distant non-irradiated cancer cells. Here, the viability and intracellular ROS levels of plasma-irradiated and non-irradiated cancer cells were monitored in vitro. Our results showed that CAP may induce plasma-irradiated cancer cells (A549 cells, A375 cells, J82 cells and HT29 cells) to secrete soluble factors into the cell culture medium, which can transmit plasma-induced anticancer effects from plasma-irradiated cancer cells to non-irradiated cancer cells. Our research confirmed that plasma-induced anticancer effects can be transmitted between cancer cells.

Experimental Study of Laser-Induced Cavitation Bubbles near Wall: Plasma Shielding Observation

To investigate the plasma shielding of laser-induced cavitation bubbles near a wall, a pulsed laser with different energies was selected to induce cavitation bubbles on the surface of 7050-T7451 aluminum alloy. A high-speed camera captured the evolution of the cavitation bubble, while a fiber-optic hydrophone system collected the acoustic signals during the evolution. Finally, a confocal microscope was used to view and analyze the surface morphology of 7050 aluminum alloy. The experimental results indicate that as the laser energy increases, the diameter, the evolution time, the pressure of the bubble, and both the pit diameter and depth all increase. Beyond an energy level of 1.4 J, the maximum diameter and the evolution time of the laser-induced cavitation bubble begin to decrease; the maximum diameter decreases by 2.04%, and the first evolution time decreases by 3.26%. Plasma shielding was observed in this experiment. Considering that the essence of a laser-induced cavitation bubble is the interaction between a high-energy laser and a liquid medium, the abnormal decrease in the maximum diameter, evolution time, and sound pressure epitomizes the manifestation of plasma shielding.

Evaluation of Anti-angiogenic Activity of Iraqi Mesembryanthemum cordifolium using rat aorta ring assay

New blood vessels are produced during angiogenesis, which is necessary in both normal and abnormal physiological and pathologic states. The use of non-toxic plant extracts that inhibit angiogenesis might lead to more focus on the use of natural sources as a pivotal therapeutic agent in the treatment of many diseases and malignancies. Mesembryanthemum cordifolium is belongs to the Aizoaceae family and commonly known as the Heartleaf Ice Plant or Tiny Sun Rose. The plant was cultivated in the city of al Diwaniyah. No previous research has been conducted on this plant and its antiangiogenic properties. Hence, this research aimed to assess the antiangiogenic capacity of the Iraqi M. cordifolium. For this study, male albino rats aged 12 to 14 weeks were used. With a Soxhlet apparatus, the defatted plant components were extracted in 85 % methanol for 12 h. Subsequently, each fraction was fractionated using petroleum ether, chloroform and ethyl acetate and each fraction underwent phytochemical analysis. Rat aortic rings were infused with 100 ?g/mL of each plant component and placed in a growth medium. In addition, the dose-response relationship was assessed for the most active fraction at 6 different concentrations ranging from 6.25 ?g/mL to 100 ?g/mL. Compared to the negative control (1 % DMSO), the results demonstrated that fractions of M. cordifolium inhibit the growth of blood vessels in a dose-dependent manner; chloroform demonstrates the most potent effect. The results indicate that the chloroform fraction derived from M. cordifolium has a good ability to limit blood vessel development. This makes it a viable option for future investigation as an angiogenesis inhibitor.

Integrated biorefinery approach for utilization of wood waste into levulinic acid and 2-Phenylethanol production under mild treatment conditions

In a bid to explore the on-site biorefinery approach for conversion of forestry residues, lignocellulosic biomass into value-added products was studied. The bark white pine wood was subjected to the microwave technique of fast and slow hydrolysis under varying acid and biomass concentrations to produce levulinic acid (LA). The HCl (2% v/v) and plant biomass (1% w/v) were identified as the optimum conditions for fast wood hydrolysis (270 ºC for 12 sec), which led to maximum LA yield of 446.68 g/kgPB. The proposed sustainable approach is mild, quick, and utilized a very low concentration of the HCl for the production of LA. The hydrolysate was used as a medium for Kluyveromyces marxianus growth to produce 2-phenylethanol (2-PE). K. marxianus used 74–95% of furfural from hydrolysate as a co-substrate to grow. The proposed model of the integrated biorefinery is an affordable on-site approach of using forest waste into localized solutions to produce LA and 2-PE.

DIVERSITY AND PHYTATE-DEGRADING POTENTIAL OF YEAST MICROORGANISMS ISOLATED FROM SOURDOUGH

Phytases, which perform the stepwise hydrolysis of phytic acid to myo-inositol and inorganic phosphate, are used worldwide to reduce phosphorus pollution and improve nutrition in monogastric animals and humans. Yeasts isolated from their natural environments represent rich and still underexplored sources of industrially valuable enzymes, including phytases; therefore, they are widely studied for the production of these enzymes. In this regard, thirteen yeast pure cultures were isolated from the microbial consortium of four types of sourdough obtained during the natural fermentation of different grain-based flours. Ten of the newly isolated yeast strains were selected as potential phytase producers based on their growth in liquid culture media with sodium phytate as the sole source of phosphorus. Using 18S rDNA and D1/D2 26S rDNA analyses, the species affiliation of the selected isolates was established. They referred to seven yeast species from 3 families, with the most significant representation of the family Saccharomycetaceae.Intracellular phytate-degrading activity was found in 8 isolates, the highest being in Nakaseomyces glabratus strain 7-4. The highest level of extracellular phytase was measured in Pichia membranifaciens strain 5-2. Both isolates showed significant antioxidant capacity higher than those of ascorbic acid.

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.