Bacterial Growth Research Articles

Cold Plasma Deposition of Tobramycin as an Approach to Localized Antibiotic Delivery to Combat Biofilm Formation

Hospital-acquired infections (HAIs) remain a significant factor in hospitals, with implant surfaces often becoming contaminated by highly resistant strains of bacteria. Recent studies have shown that electrical plasma discharges can reduce bacterial load on surfaces, and this approach may help augment traditional antibiotic treatments. To investigate this, a cold atmospheric plasma was used to deposit tobramycin sulphate onto various surfaces, and the bacterial growth rate of K. pneumoniae in its planktonic and biofilm form was observed to probe the interactions between the plasma discharge and the antibiotic and to determine if there were any synergistic effects on the growth rate. The plasma-deposited tobramycin was still active after passing through the plasma field and being deposited onto titanium or polystyrene. This led to the significant inhibition of K. pneumoniae, with predictable antibiotic dose dependence. Separate studies have shown that the plasma treatment of the biofilm had a weak antimicrobial effect and reduced the amount of biofilm by around 50%. Combining a plasma pre-treatment on exposed biofilm followed by deposited tobramycin application proved to be somewhat effective in further reducing biofilm growth. The plasma discharge pre-treatment produced a further reduction in the biofilm load beyond that expected from just the antibiotic alone. However, the effect was not additive, and the results suggest that a complex interaction between plasma and antibiotic may be at play, with increasing plasma power producing a non-linear effect. This study may contribute to the treatment of infected surgical sites, with the coating of biomaterial surfaces with antibiotics reducing overall antibiotic use through the targeted delivery of therapeutics.

Citrus aurantium L. PEELS AND SEEDS: PHYTOCHEMICAL SCREENING AND ANTIBACTERIAL ACTIVITY

In this intriguing study, orange peel and seed extracts were tested for their antibacterial effects against pathogens isolated from urinary tract infections and wound swabs. Ethanol and acetone extracts demonstrated potent antibacterial activity against Staphylococcus aureus, Klebsiella pneumoniae, Proteus mirabilis, Escherichia coli, and Staphylococcus epidermidis. The ethanol extract showed larger inhibition zones against P. mirabilis (27 mm) compared to acetone extract. There was a significant decrease in bacterial growth when acetone extract was used, with the largest inhibition observed E. coli (23 mm). The phytochemical analysis revealed the presence of tannins, flavonoids, terpenoids, steroids, alkaloids, and saponin in the extracts, except for acetone extract lacking terpenoids and saponin. This in vitro study demonstrates the significant antibacterial activity of Citrus aurantium peels and seeds against a range of common bacterial pathogens. These findings warrant further investigation to assess the potential real-world applications of these extracts, including toxicity testing and determination of optimal dosage.

Unlocking the genome of the non-sourdough Kazachstania humilis MAW1: insights into inhibitory factors and phenotypic properties.

Ascomycetous budding yeasts are ubiquitous environmental microorganisms important in food production and medicine. Due to recent intensive genomic research, the taxonomy of yeast is becoming more organized based on the identification of monophyletic taxa. This includes genera important to humans, such as Kazachstania. Until now, Kazachstania humilis (previously Candida humilis) was regarded as a sourdough-specific yeast. In addition, any antibacterial activity has not been associated with this species. Previously, we isolated a yeast strain that impaired bio-hydrogen production in a dark fermentation bioreactor and inhibited the growth of Gram-positive and Gram-negative bacteria. Here, using next generation sequencing technologies, we sequenced the genome of this strain named K. humilis MAW1. This is the first genome of a K. humilis isolate not originating from a fermented food. We used novel phylogenetic approach employing the 18S-ITS-D1-D2 region to show the placement of the K. humilis MAW1 among other members of the Kazachstania genus. This strain was examined by global phenotypic profiling, including carbon sources utilized and the influence of stress conditions on growth. Using the well-recognized bacterial model Escherichia coli AB1157, we show that K. humilis MAW1 cultivated in an acidic medium inhibits bacterial growth by the disturbance of cell division, manifested by filament formation. To gain a greater understanding of the inhibitory effect of K. humilis MAW1, we selected 23 yeast proteins with recognized toxic activity against bacteria and used them for Blast searches of the K. humilis MAW1 genome assembly. The resulting panel of genes present in the K. humilis MAW1 genome included those encoding the 1,3-β-glucan glycosidase and the 1,3-β-glucan synthesis inhibitor that might disturb the bacterial cell envelope structures. We characterized a non-sourdough-derived strain of K. humilis, including its genome sequence and physiological aspects. The MAW1, together with other K. humilis strains, shows the new organization of the mating-type locus. The revealed here pH-dependent ability to inhibit bacterial growth has not been previously recognized in this species. Our study contributes to the building of genome sequence-based classification systems; better understanding of K.humilis as a cell factory in fermentation processes and exploring bacteria-yeast interactions in microbial communities.

Novel Photothermal Graphene-Based Hydrogels in Biomedical Applications

In the last decade, photothermal therapy (PTT) has attracted tremendous attention because it is non-invasive, shows high efficiency and antibacterial activity, and minimizes drug side effects. Previous studies demonstrated that PTT can effectively inhibit the growth of bacteria and promotes cell proliferation, accelerating wound healing and tissue regeneration. Among different NIR-responsive biomaterials, graphene-based hydrogels with photothermal properties are considered as the best candidates for biomedical applications, due to their excellent properties. This review summarizes the current advances in the development of innovative graphene-based hydrogels for PTT-based biomedical applications. Also, the information about photothermal properties and the potential applications of graphene-based hydrogels in biomedical therapies are provided. These findings provide a great potential for supporting their applications in photothermal biomedicine.

Development of CuO Nanoparticles from the Mucus of Garden Snail Cornu aspersum as New Antimicrobial Agents

Several biologically active compounds involved in the green synthesis of silver and gold nanoparticles have been isolated from snail mucus and characterized. This paper presents a successful method for the application of snail mucus from Cornu aspersum as a bioreducing agent of copper sulfate and as a biostabilizer of the copper oxide nanoparticles (CuONPs-Muc) obtained. The synthesis at room temperature and neutral pH yielded nanoparticles with a spherical shape and an average diameter of 150 nm. The structure and properties of CuONPs-Muc were characterized using various methods and techniques, such as ultraviolet–visible spectroscopy (UV–vis), high-performance liquid chromatography (HPLC), one-dimensional polyacrylamide gel electrophoresis (1D-PAGE), up-conversion infrared spectroscopy Fourier transform (FTIR), scanning electron microscopy combined with energy dispersive spectroscopy (SEM/EDS), Raman spectroscopy and imaging, thermogravimetric analysis (TG-DSC), etc. Mucus proteins with molecular weights of 30.691 kDa and 26.549 kDa were identified, which are involved in the biogenic production of CuONPs-Muc. The macromolecular shell of proteins formed around the copper ions contributes to a higher efficiency of the synthesized CuONPs-Muc in inhibiting the bacterial growth of several Gram-positive (Bacillus subtilis NBIMCC2353, Bacillus spizizenii ATCC 6633, Staphylococcus aureus ATCC 6538, Listeria innocua NBIMCC8755) and Gram-negative (Escherichia coli ATCC8739, Salmonella enteitidis NBIMCC8691, Salmonella typhimurium ATCC 14028, Stenotrophomonas maltophilia ATCC 17666) bacteria compared to baseline mucus. The bioorganic synthesis of snail mucus presented here provides CuONPs-Muc with a highly pronounced antimicrobial effect. These results will expand knowledge in the field of natural nanomaterials and their role in emerging dosage forms.

Substrate geometry affects population dynamics in a bacterial biofilm

Biofilms inhabit a range of environments, such as dental plaques or soil micropores, often characterized by noneven surfaces. However, the impact of surface irregularities on the population dynamics of biofilms remains elusive, as most experiments are conducted on flat surfaces. Here, we show that the shape of the surface on which a biofilm grows influences genetic drift and selection within the biofilm. We culture Escherichia coli biofilms in microwells with a corrugated bottom surface and observe the emergence of clonal sectors whose size corresponds to that of the corrugations, despite no physical barrier separating different areas of the biofilm. The sectors are remarkably stable and do not invade each other; we attribute this stability to the characteristics of the velocity field within the biofilm, which hinders mixing and clonal expansion. A microscopically detailed computer model fully reproduces these findings and highlights the role of mechanical interactions such as adhesion and friction in microbial evolution. The model also predicts clonal expansion to be limited even for clones with a significant growth advantage-a finding which we confirm experimentally using a mixture of antibiotic-sensitive and antibiotic-resistant mutants in the presence of sublethal concentrations of the antibiotic rifampicin. The strong suppression of selection contrasts sharply with the behavior seen in range expansion experiments in bacterial colonies grown on agar. Our results show that biofilm population dynamics can be affected by patterning the surface and demonstrate how a better understanding of the physics of bacterial growth can be used to control microbial evolution.

Blue-Light-Activated Water-Soluble Sn(IV)-Porphyrins for Antibacterial Photodynamic Therapy (aPDT) against Drug-Resistant Bacterial Pathogens.

Antimicrobial resistance has emerged as a global threat to the treatment of infectious diseases. Antibacterial photodynamic therapy (aPDT) is a promising alternative approach and is highly suitable for the treatment of cutaneous bacterial infections through topical applications. aPDT relies on light-responsive compounds called photosensitizer (PS) dyes, which generate reactive oxygen species (ROS) when induced by light, thereby killing bacterial cells. Despite several previous studies in this area, the molecular details of targeting and cell death mediated by PS dyes are poorly understood. In this study, we further investigate the antibacterial properties of two water-soluble Sn(IV) tetrapyridylporphyrins that were quaternized with methyl and hexyl groups (1 and 2). In this follow-up study, we demonstrate that Sn(IV)-porphyrins can be photoexcited by blue light (a 427 nm LED) and exhibit various levels of bactericidal activity against both Gram-(+) and Gram-(-) strains of bacteria. Using localization studies through fluorescence microscopy, we show that 2 targets the bacterial membrane more effectively than 1 and exhibits comparatively higher aPDT activity. Using multiple fluorescence reporters, we demonstrate that photoactivation of 1 and 2 results in extensive collateral damage to the bacterial cells including DNA cleavage, membrane damage, and delocalization of central systems necessary for bacterial growth and division. In summary, this investigation provides deep insights into the mechanism of bacterial killing mediated by the Sn(IV)-porphyrins. Moreover, our approach offers a new method for evaluating the activity of PS, which may inspire the discovery of new PS with enhanced aPDT activity.

Urinalysis and culture results of free-catch urine samples in dogs: a randomised controlled trial.

To evaluate the prevalence of bacterial presence in free-catch urine samples preceded by either a standardised prepped ("clean-catch") protocol versus unprepped (non-cleaned) voiding. The study was a single-centre prospective single-blinded randomised controlled trial. Urine samples were obtained from 100 client-owned dogs presenting for routine evaluation. Dogs were randomly assigned to either the prepped group (preputial or peri-vulvar area cleaned with sterile saline before collection) or the unprepped group (no preliminary cleansing) stratified by sex. Urinalysis and urine culture (blood and MacConkey agar) were performed on all samples. Significant bacterial presence on urine culture was defined as >104 colony forming units (CFU)/mL. There were no statistically significant associations between prepped versus unprepped collection method or sex with a urinalysis positive for bacteriuria. However, on culture, significant bacterial growth was almost five times more likely to be associated with males relative to females (odds ratio 4.59, 95% confidence interval 1.61 to 13.10). The probability of finding a positive culture was not statistically associated with prep method (odds ratio 1.43, 95% confidence interval 0.50 to 4.08). For the majority of dogs without clinical signs of urinary tract infection, free-catch urine collection does not result in significant bacteriuria found on analysis or culture. The presence of bacteria found in free-catch samples may be secondary to sample contamination or subclinical bacteriuria. Sample contamination or subclinical bacteriuria may be more prevalent in male dogs.

Bactericidal Permeability-Increasing Protein (BPI) Inhibits Mycobacterium tuberculosis Growth

Bactericidal permeability-increasing protein (BPI) is a multifunctional cationic protein produced by neutrophils, eosinophils, fibroblasts, and macrophages with antibacterial anti-inflammatory properties. In the context of Gram-negative infection, BPI kills bacteria, neutralizes the endotoxic activity of lipopolysaccharides (LPSs), and, thus, avoids immune hyperactivation. Interestingly, BPI increases in patients with Gram-positive meningitis, interacts with lipopeptides and lipoteichoic acids of Gram-positive bacteria, and significantly enhances the immune response in peripheral blood mononuclear cells. We evaluated the antimycobacterial and immunoregulatory properties of BPI in human macrophages infected with Mycobacterium tuberculosis. Our results showed that recombinant BPI entered macrophages, significantly reduced the intracellular growth of M. tuberculosis, and inhibited the production of the proinflammatory cytokine tumor necrosis factor-alpha (TNF-α). Furthermore, BPI decreased bacterial growth directly in vitro. These data suggest that BPI has direct and indirect bactericidal effects inhibiting bacterial growth and potentiating the immune response in human macrophages and support that this new protein’s broad-spectrum antibacterial activity has the potential for fighting tuberculosis.

Toward sustainable menstrual health management: focus on super absorbent polymers

AbstractIn low- to middle-income communities, the lack of affordability of conventional sanitary products during menstrual cycles can cause psychological and health issues, ultimately affecting their quality of life. It is crucial to develop alternative products that are affordable and accessible to all while also promoting menstrual health and hygiene. Super absorbent polymers (SAPs) are a vital component in current disposable sanitary pads and nappies. However, these SAPs are often non-biodegradable and non-biocompatible. Therefore, the use of eco-friendly materials for the production of SAPs is gaining popularity in the hygiene industry, as it offers a means to reduce the carbon footprint and environmental impact associated with traditional SAPs made from non-renewable petroleum-based materials. SAPs made from polysaccharides often have naturally occurring antibacterial properties, making them appealing for commercial applications in sanitary products such as sanitary pads. In addition, the move toward reusable sanitary pads with antibacterial properties can significantly reduce waste generated by single-use products and prevent the growth of bacteria, improving the safety and hygiene of the product. Furthermore, computational modeling and artificial intelligence are now important tools in SAP synthesis, providing advantages such as predicting polymer properties, rationalizing synthesis pathways, and improving quality control. These tools can reduce synthesis costs by eliminating the need for trial-and-error approaches in polymer synthesis, ultimately promoting more affordable products for end users. Overall, these advancements in polymer synthesis and material design can help to create a more sustainable industry and promote menstrual hygiene and product accessibility to those who need it most.

A role for the stringent response in ciprofloxacin resistance in Pseudomonas aeruginosa

Pseudomonas aeruginosa is a major cause of nosocomial infections and the leading cause of chronic lung infections in cystic fibrosis and chronic obstructive pulmonary disease patients. Antibiotic treatment remains challenging because P. aeruginosa is resistant to high concentrations of antibiotics and has a remarkable ability to acquire mutations conferring resistance to multiple groups of antimicrobial agents. Here we report that when P. aeruginosa is plated on ciprofloxacin (cipro) plates, the majority of cipro-resistant (ciproR) colonies observed at and after 48 h of incubation carry mutations in genes related to the Stringent Response (SR). Mutations in one of the major SR components, spoT, were present in approximately 40% of the ciproR isolates. Compared to the wild-type strain, most of these isolates had decreased growth rate, longer lag phase and altered intracellular ppGpp content. Also, 75% of all sequenced mutations were insertions and deletions, with short deletions being the most frequently occurring mutation type. We present evidence that most of the observed mutations are induced on the selective plates in a subpopulation of cells that are not instantly killed by cipro. Our results suggests that the SR may be an important contributor to antibiotic resistance acquisition in P. aeruginosa.

Discovery of novel amide derivatives as potent quorum sensing inhibitors of Pseudomonas aeruginosa

With the increasing reports of antibiotic resistance in this species, Pseudomonas aeruginosa is a common human pathogen with important implications for public health. Bacterial quorum sensing (QS) systems are potentially broad and versatile targets for developing new antimicrobial compounds. While previous reports have demonstrated that certain amide compounds can inhibit bacterial growth, there are few reports on the specific inhibitory effects of these compounds on bacterial quorum sensing systems. In this study, thirty-one amide derivatives were synthesized. The results of the biological activity assessment indicated that A9 and B6 could significantly inhibit the expression of lasB, rhlA, and pqsA, effectively reducing several virulence factors regulated by the QS systems of PAO1. Additionally, compound A9 attenuated the pathogenicity of PAO1 to Galleria mellonella larvae. Meanwhile, RT-qPCR, SPR, and molecular docking studies were conducted to explore the mechanism of these compounds, which suggests that compound A9 inhibited the QS systems by binding with LasR and PqsR, especially PqsR. In conclusion, amide derivatives A9 and B6 exhibit promising potential for further development as novel QS inhibitors in P. aeruginosa.

Impact of the environmental parameters on Single Cell Protein production and composition by Cupriavidus necator

Due to the rapid increase in the world's population, many developing countries are facing malnutrition problems, including famine and food insecurity. Particularly, the deficiency of protein sources becomes a serious problem for human and animal nutrition. In this context, Single Cell Proteins, could be exploited as an alternative source of unconventional proteins. The aim of the study was to investigate SCP production and composition by Cupriavidus necator under various environmental conditions, temperature and pH values. A mono-factorial approach was implemented using batch bioreactor cultures under well-controlled conditions. Results were compared in terms of bacterial growth and SCP composition (proteins, nucleic acids, amino acids and elemental formula). Complementary analyses were performed by flow cytometry to study cell morphology, membrane permeability and the presence of Poly(3-hydroxybutyrate) (PHB) production. Our data confirmed the ability of C. necator to produce high amount of proteins (69% DW at 30°C and pH7). The results showed that temperature and pH independently impact SCP production and composition. This impact was particularly observed at the highest temperature (40°C) and also the lowest pH value (pH5) providing lower growth rates, cell elongation, changes in granularity and lower amounts of proteins (down to 44%DW at pH5) and nucleic acids. These low percentages were related to the production of PHB production (up to 44%DW at 40°C) which is the first report of a PHB accumulation in C. necator under nutrient unlimited conditions.

In Vitro Fermentation Shows Polyphenol and Fiber Blends Have an Additive Beneficial Effect on Gut Microbiota States

Polyphenols and fermentable fibers have shown favorable effects on gut microbiota composition and metabolic function. However, few studies have investigated whether combining multiple fermentable fibers or polyphenols may have additive beneficial effects on gut microbial states. Here, an in vitro fermentation model, seeded with human stool combined from 30 healthy volunteers, was supplemented with blends of polyphenols (PP), dietary fibers (FB), or their combination (PPFB) to determine influence on gut bacteria growth dynamics and select metabolite changes. PP and FB blends independently led to significant increases in the absolute abundance of select beneficial taxa, namely Ruminococcus bromii, Bifidobacterium spp., Lactobacillus spp., and Dorea spp. Total short-chain fatty acid concentrations, relative to non-supplemented control (F), increased significantly with PPFB and FB supplementation but not PP. Indole and ammonia concentrations decreased with FB and PPFB supplementation but not PP alone while increased antioxidant capacity was only evident with both PP and PPFB supplementation. These findings demonstrated that, while the independent blends displayed selective positive impacts on gut states, the combination of both blends provided an additive effect. The work outlines the potential of mixed substrate blends to elicit a broader positive influence on gut microbial composition and function to build resiliency toward dysbiosis.

Biosynthesis Optimization of Antibacterial-Magnetic Iron Oxide Nanoparticles from Bacillus megaterium.

The occurrence of antibiotic resistance on common bacterial agents and the need to use new generations of antibiotics have led to the use of various strategies for production. Taking inspiration from nature, using bio-imitation patterns, in addition to the low cost of production, is advantageous and highly accurate. In this research, we were able to control the temperature, shake, and synthesis time of the synthesis conditions of Bacillus megaterium bacteria as a model for the synthesis of magnetic iron nanoparticles and optimize the ratio of reducing salt to bacterial regenerating agents as well as the concentration of salt to create iron oxide nanoparticles with more favorable properties and produced with more antibacterial properties. Bacterial growth was investigated by changing the incubation times of pre-culture and overnight culture in the range of the logarithmic phase. The synthesis time, salt ratio, and concentration were optimized to achieve the size, charge, colloidal stability, and magnetic and antibacterial properties of nanoparticles. The amount of the effective substance produced by the bacteria was selected by measuring the amount of the active substance synthesized using the free radical reduction (DPPH) method. With the help of DPPH, the duration of the synthesis was determined to be one week. Characterizations such as UV-vis spectroscopy, FTIR, FESEM, X-ray, and scattering optical dynamics were performed and showed that the nanoparticles synthesized with a salt concentration of 80mM and a bacterial suspension to salt ratio of 2:1 are smaller in size and have a light scattering index, a PDI index close to 0.1, and a greater amount of reducing salt used in the reaction during one week compared to other samples. Moreover, they had more antibacterial properties than the concentration of 100mM. As a result, better characteristics and more antibacterial properties than common antibiotics were created on E. coli and Bacillus cereus.

Synthesis of Nanosized γ-Cyclodextrin Metal-Organic Frameworks as Carriers of Limonene for Fresh-Cut Fruit Preservation Based on Polycaprolactone Nanofibers.

To address the issue of bacterial growth on fresh-cut fruits, this paper reports the synthesis of nanosized γ-cyclodextrin metal-organic frameworks (CD-MOFs) using an ultrasound-assisted method and their application as carriers of limonene for antibacterial active packaging. The effects of the processing parameters on the morphology and crystallinity of the CD-MOFs are investigated, and the results prove that the addition of methanol is the key to producing nanosized CD-MOFs. The limonene loading content of the nanosized CD-MOFs can reach approximately 170mg g-1. The sustained-release behaviors of limonene in the CD-MOFs are evaluated. Molecular docking simulations reveal the distribution and binding sites of limonene in the CD-MOFs. CD-MOFs are deposited on the surfaces of polycaprolactone (PCL) nanofibers via an immersion method, and limonene-loaded CD-MOF@PCL nanofibers are prepared. The morphology, crystallinity, thermal stability, mechanical properties, and antibacterial activity of the nanofibers are also studied. The nanofiber film effectively inhibits bacterial growth and prolongs the shelf life of fresh-cut apples. This study provides a novel strategy for developing antibacterial active packaging materials based on CD-MOFs and PCL nanofibers.

FUNCTIONAL COMPONENTS AND MEDICINAL PROPERTIES FOODS

The famous phrase "Let food be the medicine" (attributed to Hippocrates) basis for both food science and nutraceuticals. Numerous bioactive substances can be found in food components, such as nutritional elements like proteins, carbs, vitamins, minerals, antioxidants, phenolics, and flavonoids, as well as primary and secondary metabolites. Functional foods have a greater importance for their health benefits above and beyond basic nutritional requirements. Demand for functional foods is rising as individuals become more conscious of how their diet affects their health. Prebiotics are short-chain carbohydrates that promotes the growth of healthy bacteria, are converted into fatty acids in the colon, and help the body absorb calcium and magnesium. Intestinal cancer risk is also reduced by them. However, animal products also include useful components such bioactive peptides, conjugated linolenic acid, long-chain omega-3, -6, and -9 polyunsaturated fatty acids, probiotics, and prebiotics. The review seeks to provide readers with a comprehensive perception of the potential applications of the functional food components present in food extracts. Furthermore, Research is necessary to develop novel functional foods, with exact health benefits from understanding these foods and functional elements in food play a vital role in preserving good health in the future.

Pulsed electric field‐assisted extraction of mushroom ß‐glucan from Pleurotus pulmonarius by‐product and study of prebiotic properties

SummaryPleurotus pulmonarius is one of the most widely consumed mushrooms containing low calories and fat. This study aimed to extract polysaccharides mainly ß‐glucan from P. pulmonarius by‐products including cap and stem using pulsed electric field (PEF) and study their prebiotic properties. The by‐products were subjected to PEF at a field strength of 5, 7.5 and 10 kV cm−1, a frequency of 15 Hz and a number of pulses of 12 000; then, the ß‐glucan content was determined with K‐YBGL assay test kit compared with a conventional extraction method using hot water at 100 °C for 6 h. In raw materials, crude carbohydrate contents in the cap and stem were 50.42% and 68.78%, respectively, and the ß‐glucan contents were 34.03% and 50.22%, respectively. After treated with PEF at 7.5 kV cm−1, the highest yield of 4.18% with ß‐glucan content of 14.10% was achieved. And the stem treated at 10 kV cm−1 showed the highest yield of 2.34% with ß‐glucan content of 21.39%. Comparatively lower yield and ß‐glucan contents were found in the samples treated with hot water. Scanning electron micrographs suggested that PEF caused severe damage to both samples. Additionally, the study of the prebiotic properties revealed that both products exhibited the ability to stimulate the growth of target lactic acid bacteria and the production of short‐chain fatty acid. This study suggested that PEF could enhance the extraction efficiency of β‐glucan with prebiotic potential from P. pulmonarius by‐products.

Cascade Microbial Metabolism of Ferulic Acid In Vitro Fermented by the Human Fecal Inoculum.

Ferulic acid (FA), predominantly existing in most cereals, can modulate the gut microbiome, but the influences of its metabolites on the microbial population and FA-transforming microorganisms are still unclear. In this study, FA and its potential phenolic metabolites were fermented in vitro for 24 h with the human fecal inoculum. A comparable short chain fatty acid (SCFA) production trend was observed in the presence and absence of substrates, suggesting limited contribution of FA mechanism to SCFA formation. Dihydroferulic acid, 3-(3,4-dihydroxyphenyl)propionic acid, and 3-(3-hydroxyphenyl)propionic acid were ascertained to be successive metabolites of FA, by tracking the intermediate variation. FA remarkably promoted the absolute abundances of total bacteria, while different metabolites affected bacterial growth of selective genera. Specific genera were identified as quantitatively correlating to the content of FA and its metabolites. Ultimately, FA-mediated gut microbiota modulation involves both the action of metabolizing microbes and the regulation effects of metabolites on bacterial growth.

Alocasia macrorrhiza rhizome lectin inhibits growth of pathogenic bacteria and human lung cancer cell in vitro and Ehrlich ascites carcinoma cell in vivo in mice

Cancer and antibiotic resistance represent significant global challenges, affecting public health and healthcare systems worldwide. Lectin, a carbohydrate-binding protein, displays various biological properties, including antimicrobial and anticancer activities. This study focused on anticancer and antibacterial properties of Alocasia macrorrhiza lectin (AML). AML, with a molecular weight of 11.0 ± 1.0 kDa was purified using Ion-exchange chromatography, and the homotetrameric form was detected by gel-filtration chromatography. It agglutinates mouse erythrocytes, that was inhibited by 4-Nitrophenyl-α-D-mannopyranoside. Maximum hemagglutination activity was observed below 60°C and within a pH range from 8 to 11. Additionally, it exhibited moderate toxicity against brine shrimp nauplii with LD50 values of 321 μg/ml and showed antibacterial activity against Escherichia coli and Shigella dysenteriae. In vitro experiments demonstrated that AML suppressed the proliferation of mice Ehrlich ascites carcinoma (EAC) cells by 35% and human lung cancer (A549) cells by 40% at 512 μg/ml concentration. In vivo experiments involved intraperitoneal injection of AML in EAC-bearing mice for five consecutive days at doses of 2.5 and 5.0 mg/kg/day, and the results indicated that AML inhibited EAC cell growth by 37% and 54%, respectively. Finally, it can be concluded that AML can be used for further anticancer and antibacterial studies.