Growth Medium Research Articles

Cashew apples: Physico-chemical analysis and occurrence of yeasts in plantations north of Côte d'Ivoire for processing into bioethanol and fermented beverages

The cashew apple is a pseudo-fruit that, once removed from the nut, is abandoned on plantations because the apple is not valued. The aim of this research is therefore to add value to the cashew apple by isolation yeasts with a view to fermenting this substrate to produce bioethanol and fermented beverages. Cashew apples from farmers' plantations in northern Côte d'Ivoire were subjected to physico-chemical analysis and yeast isolation. These isolated yeasts were screened for fermentative capacity and the influence of glucose, NaCl and ethanol on growth. The results indicate that cashew apples have an acid pH of 3.77 ± 0.03 with a high water content of 89.58 ± 0.49%. In addition, vitamin C content was 13.15 ± 0.12 mg/100 g and the Brix value was 8.6. Forty-one (41) yeasts were isolated and were able to produce C02 in liquid medium with different production levels. In the end, seven (7) isolates were selected as potential starters as they were able to resist the influence of NaCl, glucose and ethanol on growth.

Effect of synchronicity of amino acid supply on the synthesis of protein in C2C12 myotubes cultured in vitro

Previous studies inferred that the synthesis rate/efficiency of protein in body tissue is probably affected by synchronicity of different amino acid (AA) supply in its metabolic pool. In order to further observe the influence of synchronicity of AA supply on the synthesis of protein in cell level, a cell culture experiment in vitro was conducted with C2C12 myotubes. C2C12 myotubes were cultured for 24 h, meanwhile the culture medium was replaced for each 8 h. Those myotubes were subjected to 3 treatments (1 for controlled and 2 for tested), control myotubes were cultured with same normal complete medium within the whole 24 h, and the 2 tested myotubes were cultured with asynchronous amino acid supply medium in which the levels of different AAs (Lysine, threonine, methionine, leucine, valine and glutamic acid) either increased and then decreased or decreased and then increased, at different replaced medium time point (at 0, 8, and 16 h). However, during the whole experiment period all the 3 treated myotubes received same amount of each AA. The sample of the myotubes were used for myotube morphology, protein, AA, and proteomic analysis. The results showed that asynchronous AA nutrition affect the synthesis and degradation of myotube proteins, and the AAAS in the medium increase, thus decreasing the synthesis rate of myotube proteins (p < 0.05) and decreasing the diameter of myotubes (p < 0.05). The process of reduced protein synthesis affects the PI3K-AKT and FoxO signaling pathway by downregulating the levels of IRS1 and EGFR, and the degradation amplitude is greater than the synthesis amplitude. Therefore, this study further revealed the effect of the asynchronous supply of amino acids on myotube protein synthesis and the underlying mechanism and provided a theoretical reference for the precision of nutrition to animals.

Emodin regulated lactate metabolism by inhibiting MCT1 to delay non-small cell lung cancer progression.

Lung cancer is one of the most common malignant tumors in the world, with high incidence rate and mortality. Monocarboxylate transporter (MCT) 1 has been found to be widely expressed in various tumors and plays a crucial role in regulating energy metabolism. Emodin, as an important traditional Chinese medicine in China, has been reported to inhibit the progression of lung cancer. However, its potential mechanism has not been fully elucidated. The effects of emodin and MCT1 inhibitor AZD3965 on the proliferation, migration, and invasion of lung cancer cells were detected using cell counting kit-8 (CCK-8) assay, wound-healing assay, and transwell small chamber assay. The content of glucose, lactate, and pyruvate in the cell culture medium was detected using a glucose, lactate, and pyruvate detection kit, and also detected protein expression using western blotting. In addition, to investigate the effects of emodin and AZD3965 on lung cancer in vivo, we constructed nude mice subcutaneous transplant tumor model by subcutaneous injection of lung cancer cells. The results showed that emodin and AZD3965 could inhibit the proliferation, migration, and invasion of lung cancer cells. At the same time, they could inhibit the expression of MCT1 in lung cancer cells and promote the release of lactate, but did not affect the content of glucose and pyruvate. In vivo experiments had shown that emodin and AZD3965 could effectively inhibit the growth of lung cancer and inhibit the expression of MCT1. All in all, our data suggested that emodin inhibited the proliferation, migration, and invasion of lung cancer cells, possibly by inhibiting MCT1, providing important theoretical basis for elucidating the mechanism of emodin in treating lung cancer.

Fluorocarbon‐based Solvent‐Bath Annealing for High‐Performance Perovskite Photovoltaics

AbstractThermal annealing is a critical process in producing high‐quality perovskite films for high‐performance perovskite solar cells. Conventional TA presents challenges such as delayed heat transfer, leading to unwanted crystal growth and hindering processing scalability. Solvent‐bath annealing is an attractive approach that can improve heat transfer and promote perovskite crystallization by immersing the as‐deposited precursor film in a liquid medium. In this study, fluorocarbon‐based solvents are developed as novel solvent baths for uniform heat flow through omnidirectional annealing. In addition, the previously neglected solvent‐to‐solvent interaction between fluorocarbon and solvents for perovskite precursor is investigated by comparing two fluorocarbon solvents. By increasing the solvent‐solvent interaction, higher quality perovskite films with increased crystallinity, improved perovskite transition, and reduced film defects are achieved. As a result, the perovskite solar cells exhibited an increased power conversion efficiency with excellent reproducibility. These findings suggest that the selection of suitable solvent bath is promising for further improving perovskite quality and device performance.

Impact of Carbon Source on Bacterial Cellulose Network Architecture and Prolonged Lidocaine Release

The biosynthesis of bacterial cellulose (BC) is significantly influenced by the type of carbon source available in the growth medium, which in turn dictates the material’s final properties. This study systematically investigates the effects of five carbon sources—raffinose (C18H32O16), sucrose (C12H22O11), glucose (C6H12O6), arabinose (C5H10O5), and glycerol (C3H8O3)—on BC production by Komagataeibacter hansenii. The varying molecular weights and structural characteristics of these carbon sources provide a framework for examining their influence on BC yield, fiber morphology, and network properties. BC production was monitored through daily measurements of optical density and pH levels in the fermentation media from day 1 to day 14, providing valuable insights into bacterial growth kinetics and cellulose synthesis rates. Scanning electron microscopy (SEM) was used to elucidate fibril diameter and pore size distribution. Wide-angle X-ray scattering (WAXS) provided a detailed assessment of crystallinity. Selected BC pellicles were further processed via freeze-drying to produce a foam-like material that maximally preserves the natural three-dimensional structure of BC, facilitating the incorporation and release of lidocaine hydrochloride (5%), a widely used local anesthetic. The lidocaine-loaded BC foams exhibited a sustained and controlled release profile over 14 days in simulated body fluid, highlighting the importance of the role of carbon source selection in shaping the BC network architecture and its impact on drug release profile. These results highlight the versatility and sustainability of BC as a platform for wound healing and drug delivery applications. The tunable properties of BC networks provide opportunities for optimizing therapeutic delivery and improving wound care outcomes, positioning BC as an effective material for enhanced wound management strategies.

Prevalence, Cross Contamination, Virulence, and Multidrug Resistance Profiles of Staphylococcus aureus Isolates from Four Middle-Scale Dairy Farms in Bareilly, Northern India.

Milk, a nutritious global important food commodity, serves as an excellent medium for microbial growth as well. The foodborne pathogen Staphylococcus aureus is a commensal member of human microflora that enters the food chain through poor hygienic practices and cross contamination and causes various clinical manifestations in humans. During this study, raw milk and swab samples (milker's hand, udder, towel, milking bucket, and farm floor) were collected from four middle-scale buffalo dairy farms. The results revealed S. aureus presence in 11.6% (n = 56/448) bucket raw milk samples and 2.6% (n = 12/448) udder raw milk samples. Contrarily, S. aureus prevalence was significantly higher in farm floors (100%, n = 84/84), towel (35.7%, n = 10/28), milking bucket (11.6%, n = 56/448), milker's hand (10.7%, n = 3/28), and udder swab samples (4.0%, n = 18/448). The chi-square test yielded p values of 0.000, 0.005, and 0.0011 for udder raw milk, udder swab, and milker's hand swab, respectively. The p values of the milking bucket (p = 0.048) and farm floors (p = 0.0183) confirmed their possible role in S. aureus cross contamination. Gene amplifications of nuclease and enterotoxin A indicate potential virulence of S. aureus isolates in collected samples. Antibiotic susceptibility testing revealed multidrug resistance in 44% (n = 239) of S. aureus isolates with the highest resistance of 61% against penicillin. Resistance against ampicillin, streptomycin, and lincomycin was observed. Fewer S. aureus isolates were resistant to kanamycin and erythromycin, whereas the lowest number of resistant isolates was observed against chloramphenicol. A high prevalence of S. aureus in the farm environment and milking equipment suggested the cross contamination of potentially enterotoxin-producing and multidrug-resistant S. aureus to raw milk. Therefore, good hygiene practices should be enforced to avoid foodborne and zoonotic infections.

Effect of the culture liquid of Antarctic yeast <i>Nadsoniella nigra</i> on rooting, growth, and biochemical composition of <i>in vitro</i> grapevine (<i>Vitis vinifera</i> L.), cultivar '<i>Karmrahyut</i>'

Background: Grapevine (Vitis vinifera L.) is a globally significant fruit crop known for its nutritional and health benefits, including its role in preventing chronic diseases such as cancer and cardiovascular disorders. The bioactive compounds in grapes contribute to these benefits. Bioactive content changes due to grapevine variety and environmental conditions necessitate ongoing research. In vitro propagation provides a controlled environment for grapevine cultivation, minimizing disease risk and ensuring consistent quality. This study investigates the potential of Nadsoniella nigra (Nn), an Antarctic yeast, as a natural alternative to synthetic auxins like Indole-3-butyric acid (IBA) in grapevine micro cutting propagation. Objective: To evaluate the effectiveness of the culture liquid of Nn as a natural alternative to auxin-class hormones, using IBA as an example, for promoting rooting in grapevine microcuttings and to assess its impact on chlorophyll content, vitamin C levels, and sugar concentrations. Materials and Methods: In vitro propagation of grapevine (Vitis vinifera L.) cultivar 'Karmarhyt' was performed using half-strength Woody Plant Medium (WPM). Nn culture liquid was prepared at concentrations of 0.5, 1.0, 1.5, and 2.0 ml/L, and IBA was used at equivalent concentrations. Microcuttings were cultured on media supplemented with these treatments, with a control group maintained without growth regulators. Rooting was evaluated after 4 weeks by measuring rooting percentage, number of roots per shoot, and root length. Chlorophyll a (Chl a) and Chlorophyll b (Chl b) levels, vitamin C content, and sugar concentrations were assessed. Statistical analysis was performed using standard error and t-tests. Results: Rooting performance of grapevine microcuttings varied with treatment. Nn culture liquid promoted rooting in a dose-dependent manner, with the highest values observed at 2.0 ml/L (97.0% rooting, 7.2 roots, 13.8 cm root length). IBA treatment resulted in peak rooting at 1.0 mg/L (100% rooting) but decreased at higher concentrations, accompanied by callus formation. Chlorophyll content was higher in Nn culture liquid treated microcuttings, with a maximum total chlorophyll of 2.20 mg/g at 2.0 mg/L, compared to a peak of 2.05 mg/g in IBA-treated microcuttings at 1.0 mg/L. Sugar and vitamin C content increased with Nn culture liquid concentrations, whereas IBA showed a less consistent effect. Conclusion: Nn culture liquid was an effective natural alternative to IBA for promoting rooting in grapevine microcuttings. It improved rooting efficiency, chlorophyll content, and increased sugar and vitamin C levels, while IBA led to growth inhibition and callus formation at higher concentrations. Nn culture liquid demonstrated consistent benefits, suggesting potential for sustainable viticulture. As a result of the conducted research, it was established that the mixture of secondary metabolites contained in the liquid culture medium of Nn possesses high biological activity and can be recommended for use in plant biotechnology in vitro to promote the growth of both underground and above-ground parts. Future research could explore its use in propagating other plant species. Keywords: ´Karmrahyut´, grapevine, culture liquid of Nadsoniella nigra. in vitro propagation, functional foods

Inclusion of Reduced Graphene Oxide to Silk Fibroin Hydrogels Improve the Conductive, Swelling and Wound Healing Capacity

AbstractDeveloping dressing for wound dressings represents a significant challenge for the scientific community. In this study, a conductive hydrogel was synthesized to promote the wound‐healing process. This hydrogel is composed of silk fibroin (SF), reduced graphene oxide (rGO), and glycerol (G). The impact of modifying the SF:rGO ratio, and the G content (%), on the physicochemical and biological properties. The hydrogels were characterized using FT‐IR, SEM, XRD, TGA, swelling, mechanical resistance, and conductivity. The cytotoxicity of the materials and their wound‐healing capacity in human fibroblasts were also determined. Chemical analysis revealed that the gelation of SF occurs due to the formation of β sheet structures, which was confirmed by the shift from amide I to amide II. An Increase in the SF:rGO ratio favored swelling behavior, although increasing G reduced this effect. The swelling of the hydrogel followed a Fick diffusion mechanism. Furthermore, the increase in the SF:rGO ratio and the percentage G improved the conductivity of the materials. The hydrogels were found to be non‐cytotoxic to human fibroblasts, and those containing rGO exhibited superior wound healing capacity compared to the positive control cell culture medium. Therefore, SF:rGO hydrogels could be considered promising candidates for wound dressing.

Real-time optical fibre near-infrared chromatic dispersion analyser using collocated optical fibre gratings

We present what we believe to be a novel optical fibre device for real-time measurements of near-infrared chromatic dispersion of a liquid medium from 1100 nm to 1700 nm. This inline optical fibre chromatic dispersion analyser is based upon collocated fibre long-period gratings written adjacently in the core by femtosecond laser inscription yielding 8 attenuation bands associated with different cladding modes, yielding 8 independent measurements. This fibre device is tested on a series of chemical compounds associated with wines. The results for each compound yielded distinctive chromatic responses. A machine learning pipeline was developed that successfully clustered and classified spectral responses of the different chemicals to illustrate the distinctive responses. The limits of detection for these fibre devices ranged from 1×10−3 to 6×10−5 mol/L for the compounds associated with wines, demonstrating the potential usefulness of an optical fibre chromatic dispersion analyser is capable of monitoring in real-time effective chromatic dispersion that is not offered by any current technology.

Metabolic modelling as a powerful tool to identify critical components of Pneumocystis growth medium.

Establishing suitable in vitro culture conditions for microorganisms is crucial for dissecting their biology and empowering potential applications. However, a significant number of bacterial and fungal species, including Pneumocystis jirovecii, remain unculturable, hampering research efforts. P. jirovecii is a deadly pathogen of humans that causes life-threatening pneumonia in immunocompromised individuals and transplant patients. Despite the major impact of Pneumocystis on human health, limited progress has been made in dissecting the pathobiology of this fungus. This is largely due to the fact that its experimental dissection has been constrained by the inability to culture the organism in vitro. We present a comprehensive in silico genome-scale metabolic model of Pneumocystis growth and metabolism, to identify metabolic requirements and imbalances that hinder growth in vitro. We utilise recently published genome data and available information in the literature as well as bioinformatics and software tools to develop and validate the model. In addition, we employ relaxed Flux Balance Analysis and Reinforcement Learning approaches to make predictions regarding metabolic fluxes and to identify critical components of the Pneumocystis growth medium. Our findings offer insights into the biology of Pneumocystis and provide a novel strategy to overcome the longstanding challenge of culturing this pathogen in vitro.

Serum-Free and Protein-Free Media for the Cultivation of Recombinant Chinese Hamster Ovary (CHO) Cell Lines.

We describe the preparation of two cell culture media formulations for the culture in suspension of Chinese hamster ovary (CHO) cell lines. The first medium, Cell growth SFM Medium, is a serum-free medium designed to maintain cell growth with high-viability profiles. The second corresponds to a protein-free version optimized to increase CHO recombinant protein production (Production PFM Medium). Considerations on the use of these formulations for other cell culture assays (such as transfections) are also described.

Impact of digital marketing development on entrepreneurship

The article the influence of digital marketing on modern entrepreneurship and the restructuring of business models. It highlights how the rise of the Internet and social media has empowered consumers, prompting firms to rethink their marketing approaches. While much research focuses on the consumer perspective, this study takes the firm's viewpoint, examining how companies can leverage digital marketing and social media for growth. The second generation of Internet tools enables companies to communicate innovatively and co-create with customers. Firms' involvement in digital marketing is shaped by perceived benefits, and the study emphasizes the importance of relationship-driven customer interactions to enhance engagement. The article also provides examples of firms already adapting to this shift.

Effect of Different Purities of Seed Cells and Culture Media on the Growth Pattern and Protein Content of Spirulina Platensis

Spriulian platensis is a type of microalgae commonly used as natural fish feed. The purity of cell seedlings represents an internal factor, while the culture media acts as an external factor that can limit microalgae growth. This research investigates how varying purities of cell seedlings and culture media affect the growth patterns and protein content of Spriulian platensis, as well as to identify the optimal purity of cell seedlings and culture media that best promote growth patterns and protein content. The research method employed was an experimental design using a completely randomized factorial design with four treatment combinations and three replicates. The results showed that factor A (purity of seed cells) significantly affected growth patterns, including the lag phase duration, specific growth rate, and maximum density, but did not influence the final density Spriulian platensis. Factor B (culture media) had no significant effect on any of the variables. The combination of axenic seedlings with Pro Analis media was identified as the best treatment, producing a lag phase duration of (-4.17 ± 0.03 cells/day), a growth rate of (0.33 ± 0.01 cells/day), a maximum density of (6.43 ± 0.02 log cells/ml), and a final density of (5.78 ± 0.03 log cells/ml). The protein content across all treatments remained consistent at 58-60%. The study concludes that the purity of cell seedlings is a critical factor in determining the growth pattern of Spirulina platensis, particularly affecting the lag phase, growth rate, and maximum density.

Optimizing Growth of Melon (Cucumis melo L. cv. Madesta) in Nutrient Film Technique and Drip Irrigation Hydroponics with Varied Substrates

Hydroponic systems offer a promising solution for urban farming and the utilization of unproductive land. Successful implementation, however, requires careful optimization to select the most effective hydroponic system tailored to specific plants and environmental conditions. This study aims to compare the growth and physiological responses of Madesta melons (Cucumis melo L. cv. Madesta) cultivated using the nutrient film technique (NFT) and drip irrigation system (DIS) with variations in growth media. The Madesta melon seeds underwent a two-week germination phase in coco peat media, followed by transplanting into NFT and DIS setups utilizing diverse growth media, including rice husk, rice husk mixed with compost, and compost only. Over four weeks post-cultivation, assessments were conducted on key growth metrics such as leaf count, leaf diameter, plant height, and stem diameter. Plant physiological responses were also analyzed, encompassing chlorophyll and nitrogen levels, along with the mineral composition within leaves and fruits. Results revealed that the DIS cultivation outperformed the NFT in terms of growth outcomes. Among the varied media combinations, the rice husk and compost blend supported growth most effectively. Notably, no significant differences were observed in leaf and fruit nitrogen content between the DIS and NFT systems, and the overall mineral content of the media remained relatively stable before and after the cultivation period. Mineral content analysis revealed calcium as the predominant element in the leaves, while potassium emerged as the most abundant mineral in the fruits. This research sheds light on the potential of hydroponic systems, specifically the DIS method, for enhancing melon cultivation, emphasizing the importance of selecting appropriate growth media to maximize plant growth.

Electroosmotic Flow-Driven DNA-CNT Nanomotor via Tunable Surface-Charged Nanopore Array.

Nanomotors are usually designed to work in liquid media and carry cargo; they exhibit excellent potential for biosensing and disease treatment applications due to their small size. Graphene and carbon nanotubes (CNTs) are crucial components of rotary nanomotors because of excellent mechanical properties and adaptability to the human body. Herein, we introduce a DNA-CNT-based nanomotor that achieves its rotational control through an array of nanopores with tunable surface charges. The findings demonstrate that by adjusting the surface charge density of the nanopores and the direction of electric field, a DNA strand can be sequentially captured by the nanopores, thereby rotating the connected CNT. The transition from a four-nanopore array to a six-nanopore array reveals that reducing the step angle to 60° significantly enhances the rotational stability of the nanomotor and reduces random fluctuations caused by Brownian motion. This method improves the control stability of the nanomotor, providing robust support for future applications in nanoscale manipulation.

Production Physiology and Biochemical properties of Crude Thermophile Protease by Mild - Halophilic Bacillus thuringiensis aizawai HD 865

Objective: The current study aims to enrich the research library of Bacillus thuringensis, the most famous bacteria as a biopesticide, with a product that may enhance its ability as a biopesticide as well as its many other applications, namely the heat-tolerant alkaline protease. Methods: The strain Bacillus thuringiensis aizawai HD 865, obtained from HD Culture Collection was grown on a liquid growth medium of nutrient broth and yeast extract, and colonies were counted on agar plates. The zygote is then transferred to a skim milk environment to estimate the enzymatic activity under the different growth conditions of the growth environment (sodium chloride concentration, pH, aeration, fermentation duration), then testing the optimal conditions for enzymatic activity in the enzymatic reaction mixture (sodium chloride concentration, salinity resistance, optimum temperature, thermal stability, optimum pH and stability). Then analyze the data statistically. Results: Optimum alkaline protease medium production conditions were, 2 % NaCl, so Bacillus thuringiensis aizawai HD865 a mild - halophilic microorganism, aeration level 80%, pH 7 and 8 days of fermentation period. On the other hand, crude alkaline protease properties were found that, the optimum temperature for its activity was relatively high (70ºC), while heat-stabilities after 5 min of heating crude enzyme in boiling water bath then incubated for 15min on 30, 40, 50, 60, 70ºC, were 184.23, 178.07, 164.29, 165.51 and 121.46 Units, respectively; whereas the optimum pH was at pH 7.6 (151.76 Units) with tris buffer then at pH 9.6 with glycine - NaOH buffer; While pH stability was at pH 7.6 with tris buffer then at pH 8.4 with glycine - NaOH buffer. Thus, activities have decreased at different concentrations (0, 1, 2, 3, 4, 5 %) of sodium chloride in reaction mixture with enzyme activities (151.25, 137.35, 135.12, 135, 135.89, 114.38 Units) respectively, also decreased when rinse crude enzyme for 5 min in NaCl (0, 1, 2, 3, 4, 5 %), with (151.04, 175.57, 168.69, 154.61, 155.39 and 143.39 Units) respectively. Conclusion: Bacillus thuringiensis aizawai HD 865 strain is considered a low - salt tolerant strain, while the alkaline protease extracted from it is heat - resistant.

Dodecanoyl-L-tryptophan: A Novel Natural Antibiotic Isolated from Mesophotic Sponge-associated Salinicola sp. LHM and its Biological Function

Background: Sponge-associated microbiota plays a crucial role in maintaining host health by providing chemical defense through the synthesis of diverse secondary metabolites. However, research on these secondary metabolites is still in its early stages. Objective: The present study aimed to investigate new natural antibiotics from mesophotic sponge symbiotic microbiota and explore its in vitro antibacterial activity and preliminary biological function. Methods: Bacteria strain Salinicola sp. LHM was isolated from sponge L. birotulata L26 and identified based on the 16S rRNA gene analysis. Subsequently, the strain was fermented using a liquid M9 medium and screened for antibiotics with an antibacterial guiding assay. Extensive chromatographic methods were introduced to isolate the target compound, and its chemical structure was elucidated by spectroscopic analysis (LC-MS, NMR). The minimum inhibitory concentration (MIC) and cytotoxicity experiments evaluated the isolated compound's biological activity. Furthermore, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and quartz crystal microbalance with dissipation (QCM-D) were used to study the bactericidal mechanism of DLT. Finally, the preliminary biological function was explored by performing the cell-feeding experiment. Results: We successfully identified one novel natural antibiotic, dodecanoyl-L-tryptophan (DLT), in Salinicola sp. LHM isolated from mesophotic sponge Lotrochota birotulata L26. DLT exhibited potent antibacterial activity against the Bacillus subtilis and Staphylococcus aureus, with MIC values of 32 μM and 16 μM, respectively. The bactericidal tests showed that DLT broke the cell membrane to cause cell death by leaking the cell's inner content. Furthermore, the cell-feeding experiment proved that DLT producer- Salinicola sp. LHM could feed on the inner content of death cells. In addition, DLT also exhibited cytotoxicity against bronchial epithelial cells BEAS-2B, with an EC50 value of 150 μM, indicating a favorable selectivity profile. result: We successfully identified one novel natural antibiotic, dodecanoyl-L-tryptophan (DLT), in Salinicola sp. LHM isolated from mesophotic sponge Lotrochota birotulata L26. DLT exhibited potent antibacterial activity against the Bacillus subtilis and Staphylococcus aureus, with MIC values of 32 μM and 16 μM, respectively. The bactericidal tests showed that DLT broke the cell membrane to cause cell death by leaking the cell's inner content. Furthermore, the cell-feeding experiment proved that DLT producer- Salinicola sp. LHM could feed on the inner content of death cells. In addition, DLT also exhibited cytotoxicity against bronchial epithelial cells BEAS-2B, with an EC50 value of 150 μM, indicating a favorable selectivity profile. Conclusion: This research identified one novel natural antibiotic DLT and provided initial insights into the chemical defense exerted by Salinicola sp. LHM with its secondary metabolite DLT.

Antimicrobial activity of blue mold (Penicillium italicum) Filtrates against some species of pathogenic bacteria

Background: Penicillium saprophytic species, which primarily consume organic biodegradable materials, is a common example of a fungal species. The preparation filtrates of Penicillium italicum, a saprophyte on citrus fruits frequently linked to post-harvest diseases in this crop, were included in the current investigation. Objective: This investigation aimed determine the most efficient culture medium for the production of antibacterial secondary metabolites. Patients and Methods: included identifying the growth medium for P. italicum and produce its metabolites through the use of gas chromatography-mass spectrometry (GC MS) for both solid-state fermentation filtrate (SSFF) and liquid fermentation filtrate (LFF). Additionally, the antimicrobial activity of the mold filtrate against certain pathogenic bacteria was assessed using the agar well diffusion method. Results: indicated that the biomass used for mold growth was heavier in SSFF than LFF, and according to the findings, the selective active isolate's crude filtrate from two duplicates of the P. italicum Yeast Extract Sucrose YES culture medium was 0.063 mg, while the crude extract from rotten orange (as a solid medium) containing P. italicum was 0.11 mg. Tetracosane and other substances with a track record of therapeutic activity were found in the two mold extracts, according to GC MS data. Overall, both SSFF and LFF demonstrated antibacterial activity against Klebsiella pneumonia, Escherichia coli, Acinetobacter baumannii, Pseudomonas aeruginosa and Staphylococcus aureus, with the inhibition zones± standard deviation (IZ± SD) being 24.7± 0.57, 18.2± 0.28, 26.3± 0.59, 21.6± 0.51, and 32.8± 0.21 (for SSFF) mm and 0.0, 12.3±0.57, 28.16±0.20, 19.3±1.15, and 28±0.2 (for LFF) mm, respectively. Conclusion: the filtrate of P. italicum from a natural medium (rotted orange) as a solid state fermentation was more weighted and gave many effective metabolites compared to what was produced by liquid fermentation on a synthetic medium, and both liquid and solid fermentation filtrates demonstrated efficacy against harmful bacteria.

Growth of soil ammonia-oxidizing archaea on air-exposed solid surface

Abstract Soil microorganisms often thrive as microcolonies or biofilms within pores of soil aggregates exposed to the soil atmosphere. However, previous studies on the physiology of soil ammonia-oxidizing microorganisms (AOM), which play a critical role in the nitrogen cycle, were primarily conducted using freely suspended AOM cells (planktonic cells) in liquid media. In this study, we examined the growth of two representative soil ammonia-oxidizing archaea (AOA), Nitrososphaera viennensis EN76 and “Nitrosotenuis chungbukensis” MY2, and a soil ammonia-oxidizing bacterium, Nitrosomonas europaea ATCC 19718 on polycarbonate membrane filters floated on liquid media to observe their adaptation to air-exposed solid surfaces. Interestingly, ammonia oxidation activities of N. viennensis EN76 and “N. chungbukensis” MY2 were significantly repressed on floating filters compared to the freely suspended cells in liquid media. Conversely, the ammonia oxidation activity of N. europaea ATCC 19718 was comparable on floating filters and liquid media. N. viennensis EN76 and N. europaea ATCC 19718 developed microcolonies on floating filters. Transcriptome analysis of N. viennensis EN76 floating filter-grown cells revealed upregulation of unique sets of genes for cell wall and extracellular polymeric substance biosynthesis, ammonia oxidation (including ammonia monooxygenase subunit C (amoC3) and multicopper oxidases), and defense against H2O2-induced oxidative stress. These genes may play a pivotal role in adapting AOA to air-exposed solid surfaces. Furthermore, the floating filter technique resulted in the enrichment of distinct soil AOA communities dominated by the “Ca. Nitrosocosmicus” clade. Overall, this study sheds light on distinct adaptive mechanisms governing AOA growth on air-exposed solid surfaces.

Leakage Characteristics and Experimental Research of Staggered Labyrinth Sealing

The staggered labyrinth seal is widely used in aerospace, transportation, mining, and other fields due to its advantages of adapting to high speed, reliable sealing performance, and low or even frictionless friction between dynamic and static rotors. The traditional calculation method of labyrinth seal leakage mostly focuses on the fact that the internal medium is an ideal gas and only considers a single effect, which cannot accurately describe the leakage of liquid medium lubricating oil in the labyrinth seal. Therefore, this study focuses on the leakage characteristics of labyrinth seals, and it proposes a leakage calculation method based on liquid medium in view of the shortcomings of existing calculation methods under liquid medium conditions. By considering the thermodynamic and frictional effects of the staggered labyrinth sealing, the resistance loss and thermodynamic effect of the lubricating oil in the sealing cavity were analyzed. The flow field analysis was used to reveal the leakage law of lubricating oil under different conditions, and the factors such as total inlet pressure, spindle speed, and sealing clearance were considered. Finally, the leakage characteristics of the staggered labyrinth seal and the accuracy of the calculation method of the leakage of the staggered labyrinth seal under multiple effects were revealed through experimental verification. This study provides useful guidance for the performance optimization of labyrinth seals in practical applications.