Production Of Antibacterial Agents Research Articles

Hydrothermal synthesis of BCQD@g-C3N4 nanocomposites supporting environmental sustainability: Organic dye removal and bacterial inactivation

Various studies are being carried out on the removal of organic dyes and the production of antibacterial agents. In this study, boron-doped carbon quantum dot (BCQD) was synthesized by hydrothermal method, and BCQD@g-C3N4 nanocomposite structure was synthesized using graphitic carbon nitride (g-C3N4) as the support material. The photocatalytic activity of the synthesized nanocomposite against MO, RhB dyes, and Escherichia coli (E. coli) bacteria was investigated. The surface, morphology, molecular, and crystal properties of BCQD@g-C3N4 were investigated using characterization methods such as Transmission electron microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), Fluorescence (FL) spectrophotometer, and X-ray diffraction (XRD). As a result of TEM analysis, it was determined that the average particle size of BCQD was 5.1 ± 1.14 nm and showed a homogeneous distribution on 2D g-C3N4. In the XRD spectrum for BCQDs, the diffraction peak corresponding to the (002) amorphous carbon phase was observed at 21.65° In the PL spectrum of B-CQD@g-C3N4s, the emission value was observed at 458 nm. In the study conducted by taking advantage of the photocatalytic feature of BCQD@g-C3N4 nanocomposite, Rhodamine B (RhB) and Methyl orange (MO) were degraded by 65.58 % and 73.56 %, respectively, at the end of 120 min. Additionally, BCQD@g-C3N4 photocatalyst completely inhibited the growth of E. coli bacteria, which are frequently encountered in wastewater, at 90 minutes under sunlight. Escherichia coli (E. coli), which is frequently encountered in wastewater, BCQD@g-C3N4 completely prevented bacterial growth in the 90th minute under sunlight.

In vitro characterization of lactic acid bacteria from Indian fermented rice for probiotic applications

AimTo investigate probiotic attributes of lactic acid bacteria (LAB) isolated from under-explored Indian fermented rice for potential application in consumer health and functional product development. Methods and resultsThe isolates endured conditions resembling gastric stress, including pH (3), bile salt (4%), NaCl (6%), and phenol (0.6%). The selected isolates were identified as L. fermentum and L. plantarum strains by 16 S rRNA sequencing. In a simulated gastrointestinal tract (GIT), isolate SR1 outperformed other cultures in terms of viability. Auto-aggregation, and mucin adhesion abilities were tested for colonization potential. In which, compared to other isolates, MCR1 showed greater mucin adherence. SR1 and MCR1 showed higher percentages of auto-aggregation than GG. The auto-aggregation ranged from 9% to 88%., the levels significantly increase after 24 h incubation. The lower Salt aggregation Test (SAT) values indicated efficient hydrophobicity necessary for persistence in GIT and competitive inhibition to pathogens. All the isolates displayed considerably higher galactosidase activity than GG, isolate FCR2 expressed the highest, up to 613±0.92 Miller’s unit/ml activity. The probiotic candidates displayed broad spectrum antimicrobial activity against food-spoilage fungi and entero-pathogens. The study of safety aspects such as hemolytic, DNase activity, antibiotic susceptibility confirmed unavailability of any virulent factor. ConclusionThe isolates developed substantial galactosidase activity and significant broad-spectrum antibacterial activity. These characteristics make isolates an effective commercial option for β-galactosidase production in the food sector to create low-lactose or lactose-free products. Overall, the isolates' capacity for survival, colonization, and other useful traits may be of commercial relevance. Additionally, isolates can be researched for the production of antibacterial agents and in vivo studies for development of future functional food products. Moreover, these findings lay a robust groundwork for future exploration in probiotics, functional foods and nutraceuticals, while also shedding light on the mechanisms underlying the health benefits of the specified traditional food source. SignificanceThis investigation uncovered potential probiotic LAB of Indian fermented rice origin. By doing so, it expands our understanding of LAB diversity and presents promising candidates for applications in gut health improvement, functional food development, and exploration of natural antibacterial solutions.

Unlocking the Potential of Substrate Quality for the Enhanced Antibacterial Activity of Black Soldier Fly against Pathogens.

Globally, antibiotics are facing fierce resistance from multidrug-resistant bacterial strains. There is an urgent need for eco-friendly alternatives. Though insects are important targets for antimicrobial peptides, it has received limited research attention. This study investigated the impact of waste substrates on the production of antibacterial agents in black soldier fly (Hermetia illucens L.) larvae (HIL) and their implications in the suppression of pathogens [Bacillus subtilis (ATCC 6051), Staphylococcus aureus (ATCC 25923), Pseudomonas aeruginosa (ATCC 27853), and Escherichia coli (ATCC 25922)]. The 20% acetic acid (AcOH) extract from market waste had the highest antibacterial activity with an inhibition zone of 17.00 mm, followed by potato waste (15.02 mm) against S. aureus. Hexane extract from HIL raised on market waste also showed a significant inhibitory zone (13.06 mm) against B. subtilis. .Minimum inhibitory concentration (MIC) values recorded were 25 mg/mL against all test pathogens. The fastest time-kill of 20% AcOH extract was 4 h againstB. subtilis, E. coli, ,andP. aeruginosa. Lauric acid was also identified as the dominant component of the various hexane extracts with concentrations of 602.76 and 318.17 μg/g in HIL reared on potato and market waste, respectively. Energy from the market waste substrate correlated significantly (r = 0.97) with antibacterial activities. This study highlights the key role of substrate quality and extraction methods for enhancing the production of antibacterial agents in HIL, thus providing new insights into the development of potential drugs to overcome the alarming concerns of antimicrobial resistance.

Antibacterial Activity of Ethanolic Extract of Matricaria chamomilla, Malva cylvestris, and Capsella bursa-pastoris against Multidrug-Resistant Pseudomonas aeruginosa Strains

Background: This study aimed to determine antibacterial activity of ethanolic extract of Matricaria chamomilla (chamomile), Malva sylvestris, and Capsella bursa-pastoris against multidrug-resistant (MDR) clinical isolates of Pseudomonas aeruginosa. Methods: The plants were collected from Ziarat village of Gorgan, Iran in April 2019. The required parts of the plants were separated and completely dried in the shade. After grinding, extraction was performed by maceration method. The extract was dried at 37°C for 24 hours. To obtain a concentration of 50 mg/mL of each extract, 500 mg of the dried plant extract was dissolved in 10 mL 5% dimethyl sulfoxide and sterilized by filtration through a 0.45 µm membrane filter. For the antibacterial assay, agar well diffusion and broth microdilution methods were used. Results: Based on the results, ethanolic extracts of M. sylvestris and Capsella bursa-pastoris did not show any antibacterial activity against MDR P. aeruginosa isolates in both antibacterial assays. No inhibitory effect was observed for ethanolic extract of chamomile against P. aeruginosa isolates in agar well diffusion method as well. In broth microdilution method, the extract of chamomile leaves showed inhibitory effect and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined as 12.5 and 25 mg/mL, respectively. Conclusions: In this study, the extract of ethanolic chamomile leaves showed antibacterial activity against the MDR P. aeruginosa isolates. Thus, it can be used in the production of antibacterial agents, and it is a good option for protection against pathogenic microorganisms, as well as P. aeruginosa.

Green synthesis of silver nanoparticles using Ziziphus joazeiro leaf extract for production of antibacterial agents

The green synthesis of silver nanoparticles represents an important strategy for production of alternative antibacterial agents. Herein, the reduction of silver nanoparticles is provided by the action of leaf extract of Ziziphus joazeiro. The as-synthesized material presented pH-dependent behavior that affects the kinetics of nanoparticles nucleation and the following aggregation. Alkaline and acidic environment favors the increasing polydispersity of nanoparticles providing the production of different distribution of particle size. At neutral condition (pH 7), particles with lower size and reduced aggregation degree are obtained and present antibacterial activity against S. aureus and E. coli. The number of viable cells for both systems (from initial culture containing 104 colonies) reached negligible counting after 5 h of interaction with silver nanoparticles prepared at neutral pH.

PRODUCTION OF ANTIBACTERIAL AGENT FROM FUNGI ISOLATED FROM PHARMACEUTICAL SOIL SAMPLE BY FERMENTATION UNDER OPTIMIZED CONDITIONS

Objective: This study aimed to isolate fungi having antibacterial activity from pharmaceutical site soil sample and production of antibacterial agents by solid and submerged state fermentation under optimized conditions. Antibacterial activity of laboratory isolated and produced antibacterial agent was compared with other commercialized antibiotics to check the efficiency of laboratory produced antibacterial agent. Methods: For isolation and characterization of fungal isolates American Public Health Association standard was followed. Antibacterial activity was determined using disc diffusion and agar disc diffusion method. Results: On the basis of morphological and microscopic characteristics six fungal isolates belongs to four different genus species, i.e., Aspergillus sp. (F1, F2, F3), Penicillium sp. (F4), Rhizopus sp. (F5), and Fusarium sp. (F6), and they were tested against six bacterial isolates, i.e., Streptococcus sp. (B1), Bacillus sp. (B2), Staphylococcus sp. (B3), Bacillus sp. (B4), Bacillus sp. (B5), and Enterococcus sp. (B6). Except B4 all bacterial isolates growth were inhibited by fungal isolates. Under optimized conditions maximum zone of inhibition, i.e., 78 mm against B1 and B5 shown by F1 and F6 at 2% and 1% glucose concentration, respectively, at 10 pH. When comparison was made between commercialized antibiotics and lab produced antibacterial agents, it was observed lab produced antibacterial agent was more efficient in terms of zone of inhibition. Conclusion: Lab isolated and produced antibacterial agents were more efficient than commercialized antibiotics. This study demonstrated that lab isolated antibacterial agents isolated from six fungal isolates seems to be a stable and potent antibacterial and can be used as alternative to expensive commercialized antibiotics.

The Ecological Coherence of Temperature and Salinity Tolerance Interaction and Pigmentation in a Non-marine Vibrio Isolated from Salar de Atacama.

The occurrence of microorganisms from the Vibrio genus in saline lakes from northern Chile had been evidenced using Numerical Taxonomy decades before and, more recently, by phylogenetic analyses of environmental samples and isolates. Most of the knowledge about this genus came from marine isolates and showed temperature and salinity to be integral agents in shaping the niche of the Vibrio populations. The stress tolerance phenotypes of Vibrio sp. Teb5a1 isolated from Salar de Atacama was investigated. It was able to grow without NaCl and tolerated up to 100 g/L of the salt. Furthermore, it grew between 17° and 49°C (optimum 30°C) in the absence of NaCl, and the range was expanded into cold temperature (4–49°C) in the presence of the salt. Other additional adaptive strategies were observed in response to the osmotic stress: pigment production, identified as the known antibacterial prodigiosin, swimming and swarming motility and synthesis of a polar flagellum. It is possible to infer that environmental congruence might explain the cellular phenotypes observed in Vibrio sp. considering that coupling between temperature and salinity tolerance, the production of antibacterial agents at higher temperatures, flagellation and motility increase the chance of Vibrio sp. to survive in salty environments with high daily temperature swings and UV radiation.

Optimization of cultivation medium for the production of antibacterial agents

Optimization of the cultivation medium for production of antibiotic effective against pathogenic bacteria Staphylococcus aureus using strain of Streptomyces spp. isolated from the environment represents the aim of this study. After the biosynthesis, the medium was analyzed by determining residual sugar and nitrogen, and the antibiotic activity was determined using diffusion-disc method. Experiments were carried out in accordance with the Box-Behnken design, with three factors varied on three levels (glucose: 10.0, 30.0 and 50.0 g/L; soybean meal: 5.0, 15.0 and 25.0 g/L; phosphates: 0.5, 1.0 and 1.5 g/L) and for the optimization of selected parameters Response Surface Methodology was used. The obtained model with the desirability function of 0.985 estimates that the lowest amounts of residual sugar (0.89 g/L) and nitrogen (0.24 g/L) and the largest possible inhibition zone diameter (21.88 mm) that with its antibiotic activity against S. aureus creates the medium containing 10.0 g/L glucose, 5.0 g/L soybean meal and 1.04 g/L phosphates.

Probiotiques et cancer colorectal

The fecal flow conveys many carcinogens, and the intestinal flora plays a major role in colon health. Thus it has been suggested that some bacterial species could modulate in a positive way the mechanisms of intestinal carcinogenesis. The present article summarizes the main arguments in favor of a positive role of probiotics on the risk of colorectal tumors. Available arguments are mostly experimental, with the limits of extrapolating experimental data to human carcinogenesis. However, some studies in humans also suggest a potential beneficial effect, as for example an intervention study on adenoma recurrence. Most probably, according to the strain, probiotics exert different effects along the various steps of carcinogenesis. The most studied probiotics are lactic acid bacteriae with special interest for lactobacilli and bifidobacteriae. It has been suggested that probiotics modulate the activities of the intestinal microflora via at least three diffent mechanisms: competition and shifting of other constituents of the microflora; production of antibacterial agents thus controlling the growth of other constituents of the microflora; production of lactic acid and other organic acids, thus decreasing the intestinal pH and modulating the enzymatic activity. On-going studies, especially European studies, should enable us to better determine the potential benefits of probiotics in colorectal cancer prevention in the next few years.

Activité antibactérienne d’actinomycètes rares isolés d’échantillons de sol aride du Sud-est Algérien

On a batch of fifty-five strains of actinomycetes isolated from arid soil samples (the region of Biskra), ten different filamentous strains of actinomycetes were purified. The antibacterial activity was sought by two agar diffusion techniques against five test-bacteria ( Escherichi coli, Pseudomonas aeruginosa, Bacillus cereus, Streptococcus faecalis, and Staphylococcus aureus). The ten selected strains of actinomycetes presented an antibacterial activity which was more or less important against all the used bacteria-test. The medium effect on production of antibacterial agents by the ten strains was studied on five various culture media. The GB medium was found to be the most favourable for the production of antibacterial agents in contrast to the ISP2 medium in which only one strain produced active molecules against the bacteria-test.

Studies on the production of antibacterial agent by Erwinia carotovora and its properties.

The production of antibacterial agents (AAs) by isolates of Erwinia carotovora, the properties and their activity spectra were studied. The bacterial cell inductively produced the AA, when irradiated with UV or treated with mitomycin C at their early exponential growth phase, corresponding to the lysis of bacterial cells observed during 3-5hrs of culture after the treatment. The AAs obtained from 5hrs cultures of each isolate after UV irradiation differed from each other in their activities. In the case of one isolate, however, the activity did not vary with the difference in the induction method. All of the 17 isolates were found to have the ability to produce the agents, which were classified tentatively into 4 groups according to the similarity of their activity spectrum. The agent produced by each isolate indicated that it cannot be reproduced in the cell of each indicator. The activity of AA was found to be maintained for at least 20 days at 4C; it was retained in dialized solution but was lost by heat treatment; and it was found in the precipitate obtained by salting out the lysate. UV absorption spectra of the partially purified preparation exhibited the highest absorption at 275nm and the lowest at 260nm. The AAs appeared to be protein characterized by a large molecule. It was concluded that AAs are a kind of bacteriocin.