Strong Antibacterial Activity Research Articles

Sustainable chitosan/polyvinyl alcohol composite film integrated with sulfur-modified montmorillonite for active food packaging applications

Sulfur-functionalized montmorillonite (S-MMT), which has strong antioxidant and antibacterial activities, was prepared by forming a sulfur-amine complex using ethylenediamine (EDA). S-MMT was added to the chitosan/polyvinyl alcohol (Chi/PVA) blend polymer to develop an active food packaging film. The composite film, especially 4 wt% S-MMT-added Chi/PVA film (Chi/PVA/S-MMT4%), showed significant increases in tensile strength (∼25.1 %), elongation at the break (∼94.1 %), and UV-blocking ability (98.2 % UV-A and 100 % UV-B) compared to the neat Chi/PVA film. The Chi/PVA/S-MMT4% film also exhibited remarkable antioxidant properties (100 % ABTS and 65.4 % DPPH scavenging activity) and potent antibacterial activity (stopped the growth of L. monocytogenes and E. coli). Chicken packaged in the composite film showed a significant reduction in quality changes, including appearance, pH, thiobarbituric acid reactive substances (TBARS), and total viable colonies (TVC) over 20 days of storage. Multifunctional Chi/PVA/S-MMT films have high potential in active food packaging applications.

Antibacterial activity of closantel against methicillin-resistant Staphylococcus aureus and itsbiofilm.

The antimicrobial resistance of Staphylococcus aureus (S. aureus) has become a challenge in the treatment of infectious diseases. It is of great clinical value to discovery effective antimicrobial agents against multi-drug resistant S. aureus and its biofilms. This study aims to explore the antibacterial activity of the antiparasitic drug closantel against methicillin-resistant S. aureus and its biofilms through drug repurposing. The sensitivity of S. aureus to closantel was assessed using microbroth dilution and disk diffusion methods. The bacteriostatic and bactericidal activities of closantel were determined by time-kill curves and colony count. Scanning electron microscopy combined with SYTOX Green and DiSC3(5) fluorescence probes were used to study the bactericidal mechanism of closantel. The influence of resistance was assessed by continuous exposure to sub-inhibitory concentrations of closantel. The anti-biofilm activity was evaluated using 96-well plates and crystal violet staining, and cytotoxicity was measured using the CCK-8 assay. The minimal inhibitory concentration (MIC) of closantel for both methicillin-sensitive and methicillin-resistant S. aureus ranged from 0.125 to 1.000 μg/mL. Disk diffusion tests showed that 80 μg of closantel created an inhibition zone, which increased in diameter with higher drug amounts. Sub-inhibitory concentrations (0.031 μg/mL) of closantel significantly inhibited S. aureus proliferation, reducing bacterial turbidity from 0.26±0.00 to 0.11±0.01 (t=16.06, P<0.001), with stronger inhibition at higher concentrations. Closantel at 0.25×MIC inhibited S. aureus proliferation for 12 hours, while 1×MIC inhibited it for over 24 hours, with the number of viable bacteria decreasing as the drug concentration increased. Mechanistic studies indicated that closantel effectively disrupted the integrity of S. aureus cell membranes, significantly increasing SYTOX Green and DiSC3(5) fluorescence intensity. Even after 25 days of continuous exposure to sub-inhibitory concentrations of closantel, no resistance developed. Closantel at 0.0625 μg/mL significantly inhibited biofilm formation, reducing it from 1.29±0.16 to 0.62±0.04 (t=11.62, P<0.001), showing a clear dose-dependent effect. Closantel at 2 μg/mL also significantly eradicated established biofilms, reducing biofilm mass from 1.62±0.34 to 0.51±0.39 (t=4.84, P<0.01). Additionally, closantel exhibited extremely low cytotoxicity, with half-maximal lethal concentrations for HepG2 liver cancer cells and normal LO2 liver cells both exceeding 64 μg/mL. Closantel exhibits strong antibacterial activity against S. aureus and its biofilm with low cytotoxicity against human cells, making it a promising candidate for new therapeutic strategies against S. aureus-related infections.

Antibacterial and anti-biofilm activities of antibiotic-free phosphatidylglycerol/docosahexaenoic acid lamellar and non-lamellar liquid crystalline nanoparticles

Infectious diseases, particularly those associated with biofilms, are challenging to treat due to an increased tolerance to commonly used antibiotics. This underscores the urgent need for innovative antimicrobial strategies. Here, we present an alternative simple-by-design approach focusing on the development of biocompatible and antibiotic-free nanocarriers from docosahexaenoic acid (DHA) that has the potential to combat microbial infections and phosphatidylglycerol (DOPG), which is attractive for use as a biocompatible prominent amphiphilic component of Gram-positive bacterial cell membranes. We assessed the anti-bacterial and anti-biofilm activities of these nanoformulations (hexosomes and vesicles) against S. aureus and S. epidermidis, which are the most common causes of infections on catheters and medical devices by different methods (including resazurin assay, time-kill assay, and confocal laser scanning microscopy on an in vitro catheter biofilm model). In a DHA-concentration-dependent manner, these nano-self-assemblies demonstrated strong anti-bacterial and anti-biofilm activities, particularly against S. aureus. A five-fold reduction of the planktonic and a four-fold reduction of biofilm populations of S. aureus were observed after treatment with hexosomes. The nanoparticles had a bacteriostatic effect against S. epidermidis planktonic cells but no anti-biofilm activity was detected. We discuss the findings in terms of nanoparticle-bacterial cell interactions, plausible alterations in the phospholipid membrane composition, and potential penetration of DHA into these membranes, leading to changes in their structural and biophysical properties. The implications for the future development of biocompatible nanocarriers for the delivery of DHA alone or in combination with other anti-bacterial agents are discussed, as novel treatment strategies of Gram-positive infections, including biofilm-associated infections.

Green Synthesis of ZnO Nanoparticles for Efficient Cr(VI) Removal and Antioxidant/Microbial Properties

AbstractThe study focuses on fabrication of a cost‐effective Zinc Oxide nanoparticles (ZnONPs) adsorbent using Syngonium podophyllum leaves extract to remove hexavalent chromium (Cr6+) from synthetically prepared wastewater. Various spectroscopic techniques, including X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X‐ray analysis (EDX), and transmission electron microscopy (TEM), were used to characterize the ZnONPs. Fourier infra‐red spectroscopy (FTIR) detected that various organic compounds like flavonoids, terpenoids, and carboxylic acids acts as stabilizing and capping agent. The batch adsorption study was conducted to investigate the effects of Cr6+ adsorption time, pH, adsorbent concentration, and initial adsorbate concentration. The maximum adsorption capacity was 267.068 mg/g at 313 K. The Freundlich isotherm model was most suitable, indicating multilayer confiscation of Cr6+ on the heterogeneous surface. Chemisorption was identified as the mechanism of sequestration. Thermodynamic studies revealed that Cr6+ removal was spontaneous and feasible, with ΔG° values suggesting predominantly physisorption. Additionally, ZnONPs displayed strong antibacterial activity against S. aureus bacteria, making them a potential alternative to antibiotics. ZnONPs exhibited impressive antioxidant activity. Overall, ZnONPs synthesized through biosynthesis proved to be excellent nano‐sorbents, antioxidants, and biocompatible materials with promising applications in water remediation and healthcare.

Bactericidal Antibody Responses to Meningococcal Recombinant Outer Membrane Proteins.

Secretin PilQ is an antigenically conserved outer membrane protein that is present in most meningococci and PorA is a major protein that elicits bactericidal immune response in humans following natural disease and immunization. In the present study, BALB/c mice were immunized subcutaneously with rPilQ406-770 or rPorA together with Freund's adjuvant (FA). Serum antibody responses to serogroup A and B Neisseria meningitides whole cells or purified proteins and functional activity of antibodies were determined by ELISA and serum bactericidal assay (SBA), respectively. Serum IgG responses were significantly increased in the immunized group with rPilQ406-770 or rPorA together with FA compared to control groups. IgG antibody response of mice immunized with rPilQ406-770 was significantly more than mice immunized with rPorA (OD at 450 nm was 1.6 versus 0.83). The booster injections were effective in increasing the responses of antirPilQ406-770 or anti-rPorA IgG significantly. Antisera produced against rPilQ406-770 or rPorA demonstrated strong surface reactivity to serogroup B N. meningitides in comparison with control groups. Antisera raised against rPorA or rPilQ406-770 and FA demonstrated SBA titers from 1/1024 to 1/2048 against serogroup B. The strongest bactericidal activity was detected in sera from mice immunized with rPilQ406-770 mixed with FA. These results suggest that rPilQ406-770 is a potential vaccine candidate for serogroup B N. meningitidis.

One-pot multicomponent synthesis and antimicrobial evaluation of steroidal benzo[4,5]imidazo[1,2-a]pyrimidines with hemolytic assay and molecular docking studies

A novel class of steroidal benzo[4,5]imidazo[1,2-a]pyrimidine derivatives was successfully synthesized via one-pot three component synthesis of pregnenolone, malononitrile, and 2-aminobenzimidazole using triethylamine as a catalyst. All the synthesized compounds were characterized by FTIR, 1H NMR, 13C NMR and mass spectra. The synthesized compounds were tested for antifungal and antibacterial activities, and strong antifungal and antibacterial activities were observed in compounds 6 and 9. The antifungal activity of the synthesized compounds was screened against C. albicans, C. glabrata, and C. tropicalis. Compound 6 exhibited a MIC of 420 μg/ml for C. albicans and C. glabrata whereas C. tropicalis showed a slightly higher MIC of 440 μg/ml. Compound 9 gave an MIC of 465 μg/ml for C. albicans, 470 µg/ml for C. glabrata while 485 μg/ml for C. tropicalis. The antibacterial activity against gram-positive (E. coli) and gram-negative (S. aureus) was investigated. Compound 6 showed MIC 12 μg/ml for E. coli and 12 μg/ml for S. aureus. While compound 9 showed MIC 6 μg/ml and 12 μg/ml for E. coli and S. aureus respectively. The hemolytic assay was also performed on human red blood cells. Compounds 6, 8 and 9 were found to be least toxic to human RBCs, showing 7.32 %, 7.27 % and 7.68 % cell inhibition at MIC, respectively. Furthermore, molecular docking analysis was carried out.

Evaluation and activity of new porphyrin-peptide cage-type conjugates for the photoinactivation of Mycobacterium abscessus.

Mycobacterium abscessus is increasingly recognized as an emerging opportunistic pathogen causing severe lung diseases and cutaneous infections. However, treatment of M. abscessus infections remains particularly challenging, largely due to intrinsic resistance to a wide panel of antimicrobial agents. New therapeutic alternatives are urgently needed. Herein, we show that, upon limited irradiation with a blue-light source, newly developed porphyrin-peptide cage-type photosensitizers exert a strong bactericidal activity against smooth and rough variants of M. abscessus in planktonic cultures and in biofilms, at low concentrations. Atomic force microscopy unraveled important morphological alterations that include a wrinkled and irregular bacterial surface. The potential of these compounds for a photo-therapeutic use to treat M. abscessus skin infections requires further evaluations.IMPORTANCEMycobacterium abscessus causes persistent infections and is extremely difficult to eradicate. Despite intensive chemotherapy, treatment success rates remain very low. Thus, given the unsatisfactory performances of the current regimens, more effective therapeutic alternatives are needed. In this study, we evaluated the activity of newly described porphyrin-peptide cage-type conjugates in the context of photodynamic therapy. We show that upon light irradiation, these compounds were highly bactericidal against M. abscessus in vitro, thus qualifying these compounds for future studies dedicated to photo-therapeutic applications against M. abscessus skin infections.

A Systematic Review of the Design and Applications of Antimicrobial Peptides in Wound Healing.

The sources of antimicrobial peptides (AMPs), also known as peptide-based antibiotics, are diverse, such as plants, animals, microorganisms including human leukocytes, saliva, human defense peptides, and human sweat. These natural sources provide a rich variety of AMPs with unique characteristics and potential therapeutic applications, including wound-healing and antimicrobial properties. AMPs derived from these sources have shown promise in combating a wide range of pathogens, making them valuable targets for further research and potential clinical applications. The design of AMPs for wound healing involves a meticulous process of structurally optimizing peptides to possess a unique combination of antibacterial and wound-healing characteristics. This systematic review was produced to show the design and applications of AMPs in wound healing. The terms "antimicrobial peptides AND wound healing" were used to search for articles published between September 2023 and January 2010. In the search, we found a total of 12958 articles, of which 12898 were excluded, and the remaining 60 articles were chosen for further study. This systematic review underscores the potential of AMPs as valuable tools in infection control and wound healing, showcasing their versatility and effectiveness in combating a wide range of pathogens. Overall, AMPs in wound healing display a diverse mechanism of action, influencing the inflammatory response, encouraging tissue regeneration, and aiding tissue remodeling, along with strong antibacterial activity. Furthermore, this systematic review addresses AMP toxicity studies, which include rigorous in vitro and in vivo examinations to determine potential cytotoxic effects, systemic toxicity, and any adverse responses connected with its usage in wound-healing applications.

Design and Fabrication of Broad-Spectrum Antimicrobial Porous Metallo-Polymeric Microsphere for Water Disinfection.

An expedient and efficient approach is used to synthesize a new class of metallo-polymeric microspheres (MPMs) as antimicrobials to succumb the wide range of bacteria from water. Three types of MPMs, that is, poly[Silver (I)-methacrylate-co-methylmethacrylate] (pAgMA), poly[Copper (II)-methacrylate-co-methyl methacrylate] (pCuMA), and poly[Nickel (II)-methacrylate-co-methylmethacrylate] (pNiMA), are prepared via radical suspension polymerization technique in 3D shape with porous texture. The structural and morphological characterization of the prepared microspheres are examined by analytical techniques. The antimicrobial potentialities of prepared MPMs are investigated at the laboratory scale study, revealing that the MPMs exhibit strong antibacterial activity (≈99.9% killing) against Gram-negative and Gram-positive bacteria [Enterobacter hormaechei (EH), Bacillus megatarium (BM), and Bacillus bataviensis (BB)]. The MacConkey agar medium test reveals that MPMs have substantial biocidal efficacy against broad-spectrum Gram-negative bacteria present in tap water. The MPMs exhibit significant antimicrobial efficacy via contact killing owe to the presence of integrated biocidal metal moiety, which represents that the MPMs are safe for water disinfection.

Study of andrographolide bioactivity against Pseudomonas aeruginosa based on computational methodology and biochemical analysis.

Andrographolide is one of the main biologically active molecules isolated from Andrographis paniculata (A. paniculata), which is a traditional Chinese herb used extensively throughout Eastern Asia, India, and China. Pseudomonas aeruginosa, often known as P. aeruginosa, is a common clinical opportunistic pathogen with remarkable adaptability to harsh settings and resistance to antibiotics. P. aeruginosa possesses a wide array of virulence traits, one of which is biofilm formation, which contributes to its pathogenicity. One of the main modulators of the P. aeruginosa-controlled intramembrane proteolysis pathway is AlgW, a membrane-bound periplasmic serine protease. In this work, we have used a set of density functional theory (DFT) calculations to understand the variety of chemical parameters in detail between andrographolide and levofloxacin, which show strong bactericidal activity against P. aeruginosa. Additionally, the stability and interaction of andrographolide and levofloxacin with the protein AlgW have been investigated by molecular docking and molecular dynamics (MD) simulations . Moreover, the growth and inhibition of biofilm production by P. aeruginosa experiments were also investigated, providing insight that andrographolide could be a potential natural product to inhibit P. aeruginosa.

Antimicrobial Activity of Grapefruit Seed Extract on Edible Mushrooms Contaminations: Efficacy in Preventing Pseudomonas spp. in Pleurotus eryngii.

Pleurotus eryngii is an edible mushroom that suffers significant losses due to fungal contamination and bacteriosis. The Pseudomonadaceae family represents one of the most frequent etiologic agents. Grapefruit seed extract (GSE) is a plant extract that contains different bioactive components, such as naringin, and exhibits a strong antibacterial and antioxidant activity. Over the last decade, GSE use as an alternative to chemical treatments in the food sector has been tested. However, to our knowledge, its application on mushroom crops has never been investigated. This study focuses on evaluating GSE efficacy in preventing P. eryngii yellowing. GSE antibiotic activity, inhibitory and bactericidal concentrations, and antibiofilm activity against several microorganisms were tested with the Kirby-Bauer disk diffusion assay, the broth microdilution susceptibility test, and the Crystal violet assay, respectively. In vitro, the extract exhibited antimicrobial and antibiofilm activity against Staphylococcus aureus 6538 and MRSA (wild type), Escherichia coli ATCC 8739, and Pseudomonas spp. (Pseudomonas aeruginosa 9027, P. fluorescens (wild type)). GSE application in vivo, in pre- and post-sprouting stages, effectively prevented bacterial infections and subsequent degradation in the mushroom crops: none of the P. eryngii treated manifested bacteriosis. Our findings support the use of GSE as an eco-friendly and sustainable alternative to chemical treatments for protecting P. eryngii crops from bacterial contamination, consequently ensuring food safety and preventing financial losses due to spoilage. Furthermore, GSE's potential health benefits due to its content in naringin and other bioactive components present new possibilities for its use as a nutraceutical in food fortification and supplementation.

Synergistic photogeneration of nitric oxide and singlet oxygen by nanofiber membranes via blue and/or red-light irradiation: Strong antibacterial action

New functionalities were added to biocompatible polycaprolactone nanofiber materials through the co-encapsulation of chlorin e6 trimethyl ester (Ce6) photogenerating singlet oxygen and absorbing light both in the blue and red regions, and using 4-(N-(aminopropyl)-3-(trifluoromethyl)-4-nitrobenzenamine)-7-nitrobenzofurazan, NO-photodonor (NOP), absorbing light in the blue region of visible light. Time-resolved and steady-state luminescence, as well as absorption spectroscopy, were used to monitor both photoactive compounds. The nanofiber material exhibited photogeneration of antibacterial species, specifically nitric oxide and singlet oxygen, upon visible light excitation. This process resulted in the efficient photodynamic inactivation of E. coli not only close to nanofiber material surfaces due to short-lived singlet oxygen, but even at longer distances due to diffusion of longer-lived nitric oxide. Interestingly, nitric oxide was also formed by processes involving photosensitization of Ce6 during irradiation by red light. This is promising for numerous applications, especially in the biomedical field, where strictly local photogeneration of NO and its therapeutic benefits can be applied using excitation in the “human body phototherapeutic window” (600–850 nm). Generally, due to the high permeability of red light, the photogeneration of NO can be achieved in any aqueous environment where direct excitation of NOP to its absorbance in the blue region is limited.

Design, synthesis and preliminary antibacterial evaluation of novel 1,3-benzoxazole/carboximidamide- and 1,3-benzoxazole/3-aryl-1,2,4-oxadiazole hybrids

Two series of 1,3-benzoxazole/carboximidamides 5a-i and 1,3-benzoxazole/3-aryl-1,2,4-oxadiazoles 6a-i were prepared from the reactions of (1,3-benzoxazol-2-ylthio)acetic acid (2) with the corresponding arylamidoximes 4a-i using excess N,N'-carbonyldiimidazole (CDI). The antibacterial studies revealed that hybrid 5a demonstrated exceptional activity against the Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus, with inhibition zones measuring 34 mm and 36 mm, respectively. Moreover, hybrid 5a proved strong antibacterial activity against the against Gram-negative Klebsiella pneumoniae with inhibition zone equal to 32 mm. on the other hand, hybrid 5a displayed moderate activity against Gram-negative Escherichia coli, resulting in a 15 mm inhibition zone. Hybrid 6e (with 4-methoxyphenyl) was the most potent hybrid against B. subtilis, S. aureus and K. pneumoniae with inhibition zones equal to 32, 36 and 34 mm, respectively, followed by hybrids 6b (with 4-chlorophenyl) with inhibition zones equal to 31, 34 and 35 mm, respectively. Moreover, hybrid 5a exhibited strong antibacterial activity against B. subtilis, S. aureus and K. pneumoniae with minimum inhibitory concentration (MIC) values of 1.97, 0.97 and 3.90 μM, respectively, while hybrid 6b showed strong antibacterial activity with MIC values of 7.81, 3.90 and 3.90 μM, respectively, and hybrid 6e demonstrated antibacterial activity with MIC values of 3.90, 0.97 and 1.95 μM, respectively.

Fabrication and Therapeutic Process of a Green Silver-Nanoparticle-Embedded Mucilage Microsphere for Pathogenic-Bacteria-Infected Second-Degree Burn and Excision Wounds.

Multidrug-resistant bacteria are a serious problem in biomedical applications that decrease the wound healing process and increase the mortality rate. Therefore, in this study, we have prepared a green-synthesized silver-nanoparticle-encapsulated mucilage microsphere (HMMS@GSNP) from Hibiscus rosa sinensis leaves and applied it to pathogen-infected burn and excision wounds. Biophysical properties like size, polydispersity index, absorbance capacity, and drug release were measured by different techniques like field-emission scanning electron microscopy, dynamic light scattering, swelling ratio, etc. The strong antibacterial activity of a HMMS@GSNP microsphere was measured by minimum inhibitory concentration assay, minimum bactericidal concentration assay, and agar well diffusion methods. The HMMS@GSNP microsphere enhanced the cell viability, cell proliferation, migration, antioxidant, and antiinflammation activity compared to untreated GSNP and HMMS, as quantified by MTT assay, BrdU assay, scratch wound assay, reactive oxygen species scavenging assay, and Western blot analysis, respectively. In the in vivo experiment, we used a methicillin-resistant Staphylococcus aureus bacteria-infected, burn-and-excision-wound-created male BALB/c mice model. The HMMS@GSNP-treated burn-and-excision-wound-infected mice showed significant results compared to other groups (untreated, Silverex Ionic Gel, AgNO3, HMMS, and GSNP), and the mice tissues were utilized for bacteria count, immunoblot analysis, histological studies, and real-time polymerase chain reaction. Thus, the HMM@GSNP microsphere is an excellent therapeutic material that can be used as a topical agent for the management of chronic wound therapy.

Bioactivity of Endophytic Fungi Isolates from Syzygium malaccense Twigs

Searching for medicinal raw materials derived from the isolation of secondary metabolite compounds is still being carried out to cure a range of illnesses, including infections and degenerative diseases caused by bacteria and free radicals. This research used endophytic fungi extract from the twig of Syzygium malaccense. The diffusion method was used for antibacterial activity and 2,2-diphenyl-1-picrylhydrazyl (DPPH) was used for antioxidant activity. Chemical compound was identified by using NMR spectroscopic method. This research found 5 isolate of endophytic fungi from twig of S. malaccense (YR1 – YR5). Strong antibacterial and antioxidant activity were showed by YR5. Based on molecular identification, YR5 was Fusarium verticillioides. Pure compound prodeced by endophytic fungi F. verticilloides was naphthalene (3-methoxy-7 methylnaphthalene-1,6-diol). This finding can be used as a basis for drug development.

Atlas pistachio (Pistacia atlantica) unripe fruit extract as a source of phytochemicals with anti-tyrosinase, antioxidant, and antibacterial properties

The current need for biologically active substances that are sustainable, allegedly beneficial to health, and may be employed as ingredients in cosmetic products has encouraged numerous researchers. Pistacia atlantica is known to contain compounds that possess strong biological effects beneficial to health. The objective of this study was the quantification of the polyphenols in unripe Atlas pistachio (AP) fruit extract and the evaluation of hydro-methanolic extract and anthocyanins for their antioxidant, anti-tyrosinase, and antimicrobial effects. The results revealed that the yield of the hydro-methanolic extract was 22.15%, characterized by 75.12 mg GAE/g DM for total phenolics and strong content of hydrolysable tannins (400.16 mg GAE/g DM). 1,1-dimethyl-allyl caffeate, hydroxytyrosol, ellagic acid, rutin, and kaempferol-3-O-glucoside were the most abundant components quantified by HPLC-DAD. The tyrosinase enzyme was significantly inhibited by AP extract (EC50 = 0.70 mg/mL). For the antioxidant properties, the hydrolyzed anthocyanin extract exhibited the best action against reducing power and β-carotene, compared to anthocyanins crude extract and fruits. This extract showed its stronger antibacterial activity. In conclusion, unripe AP fruit is a promising source of diverse phytochemicals that can be applied in medicinal, nutraceutical, and cosmetic applications as antioxidants and antimicrobials.

Activated carbon impregnated with Ag(0) and Cu oxides for the removal of Escherichia coli, Giardia, and Cryptosporidium (oo)cysts from water

Granular activated carbon (GAC) impregnated with silver or copper was evaluated as a point-of-use water treatment to improve the microbiological quality of drinking water processed by low-cost, newly developed GAC filters. Experiments were carried out in a point-of-use water purifying system using packed-bed filters of GAC impregnated with various concentrations of Ag(0) or Cu oxides. The pore and surface properties were studied in terms of BET volumetric measurement with nitrogen adsorption (BET area of metal-impregnated GAC lies within the range of 602 ∼ 866 m²g−1, while the surface area of non-treated GAC is 870 m²g-1), X-ray diffraction (identifying the presence of metallic silver and copper oxide in the GAC structure) and Scanning Electron Microscopy (revealed the presence of metal compounds deposited on the GAC surface). The performance of filters with GAC (water treatment capacity of 4 L/g) was evaluated against microbiological contaminants in synthetic water so that the best loading concentration to remove microorganisms from test water could be determined. The removal efficiency against Escherichia coli was higher when the amount of metal impregnated on GAC increased. GAC impregnated with Ag(0) at 5.0 wt% had a strong antibacterial activity for the growth of Escherichia coli. Samples of GAC impregnated with Ag(0) at 1.0 wt% and Cu oxides at 0.5 wt% were more efficient in the removal of Giardia and Cryptosporidium (oo) cysts. The above evaluations showed that the proposed apparatus, based on a gravitational point-of-use filter with an adsorbent with metals has antibacterial properties and may be recommended to communities for household treatment of drinking water.

Antimicrobial activity, minimum inhibitory concentration and cytotoxicity of thiadiazol compound

Aim. This study aims to investigate the biological activity and cytotoxicity of the prepared thiadiazole derivative compound. Methods. A thiadiazol chemical, 4-[5-amino 1,3,4-thiadiazole-2-yl] phenol, was prepared by reacting 2.762 grams (0.01 moles) of 4-hydroxybenzoic acid with 1.822 grams (0.01 moles) of thiosemicarbazide. The prepared thiadiazole antimicrobial activity was tested at concentrations of 30, 50, 80, and 100 mg/mL against Escherichia coli, Pseudomonas, Bacillus cereus, and Staphylococcus epidermidis. Results. The thiadiazole chemical compound was prepared and tested against several bacterial species. The minimum inhibitory concentration (MIC) for Escherichia coli, Bacillus cereus, and Staphylococcus epidermidis was 0.8 mg/mL. Pseudomonas was unaffected by this substance. Investigations were made into the cytotoxicity activities. When the concentration was less than 0.01 mg/mL, it was discovered that the produced thiadiazol also had no impact on the red blood cell. Conclusion. The results revealed that the thiadiazole chemical compound had strong antibacterial activity against some of the pathogenic bacteria. This means that the chemical compound can be used as a narrow spectrum antibiotic.

Anti-microbial activity of Ocimum sanctum L. gel against black pigmented microbes.

Black pigmented gram negative anaerobes are associated with periodontal disease and tooth loss. Therefore, it is of interest to evaluate the antimicrobial activity of Ocimum Sanctum.L (Tulsi) gel against black pigmented anaerobes. Plaque samples were collected from the subject and kept in anaerobic broth for 4 hours of incubation at 37°C. 50µL concentration of Tulsi gel was added and kept in gas pack system for 3-5 days. Zone of inhibition was measured. Ocimum sanctum L. (Tulsi) exhibits strong antibacterial activity against Black Pigmented bacteroides at 1% and 2%.Tulasi gel was effective at higher concentrations, indicating the possibility of using it as an adjunct to standard periodontal treatment.

STANDARDISATION OF BIOACTIVE MATERIALS FROM CHROMULINA FREIBERGENSISAGAINST HUMAN PATHOGENS USING GC-MS ANALYSIS

In the preceding ten years, there has been a surge in the distribution of secondary metabolites and pharmacologically dynamic compounds from marine microalgae. Chromulinafreibergensis provided the antibacterial metabolites lessons for the current research .The current secondary metabolites study was chosen to focus on the green algal Chromulinafreibergensis. To see whether the properties of pH, temperature, and salinity on the development of microalgae aided in the growth of microalgae, they were tested. Antibacterial activity against Vibrio cholerae, Klebsiella pneumonia, Escherichia coli, Pseudomonas aeruginosa, Salmonella sp., Proteus sp., Streptococcus pyrogens, Staphylococcus aureus, Bacillus megaterium, and Bacillus subtilis was tested for in different solvent extracts of Chromulinafreibergensis.On the ninth day of incubation, when the medium was adjusted to a pH of 9.0 in 30 ppt of salinity at 250C, the uppermost cell growth was noticed. Of all the investigated solvents, the butanol + isopropanol (1:1) crude extract of Chromulinafreibergensis tested the highest zone of inhibition (13.4 mm) against Salmonella. . The presence of rare chemical substances like 3, 3, 5-Trimethylheptane (M.W. 142.2) and n-Hexadecane (M.W. 226.2) in the crude extract of Chromulinafreibergensis was discovered using GC-MS analysis.These results demonstrated the strong antibacterial activity of the Chromulinafreibergensis Butanol + Isopropanol (1:1) extract, demonstrating its enormous potential as a solvent for the extraction of bioactive chemicals from natural sources for biomedical and pharmaceutical applications.