Lowest MBC Research Articles

Chemical composition and antibacterial activity of Moroccan Artemisia mesatlantica and A. absinthium essential oils against fire blight caused by Erwinia amylovora

The aim of this study was to find an alternative to chemical products used in the control of fire blight disease of rosaceous plants. In this work, essential oils of two Moroccan Artemisia species: Artemisia mesatlantica and Artemisia absinthium were screened for their antibacterial activity against Erwinia amylovora the causal agent of this disease. The EOs extraction was carried out by water distillation method in Clevenger- type apparatus and analyzed by gas Chromatography-Flame Ionization Detector (GC/FID) and by Gas Chromatography-Mass Spectrometry (GC/MS). The antibacterial activity of extracted EOs was tested in vitro based on the agar diffusion method and broth microdilution method and in vivo on detached immature pear fruits. The results revealed that the yields of extracted EOs were 1.25 and 0.58% respectively for A. mesatlantica and A. absinthium. The chemical composition analysis showed that investigated EOs were characterized with a high amount of β-Thujone (40.42% for A. mesatlantica and 36.25% for A. absinthium). Both EOs have a similar MIC value (2.08%). A. absinthium EOs were found to be more effective than A. mesatlantica EOs since they show the lowest MBC. These results indicate that EOs of A. absinthium and A. mesatlantica contained compounds with antibacterial potential against Erwinia amylovora. In the bioassay test, the application of A. absinthium EOs on detached immature pear fruits infected by E. amylovora resulted in total suppression of disease severity. Such natural products may represent a sustainable alternative to the use of chemical pesticides.

<strong>Effectiveness of ChKM solution compared to triple-antibiotic paste as an intracanal medicament for bacteria that cause a chronic periapical abscess</strong>

Introduction: Chronic periapical abscesses are caused by polymicrobial bacteria, including E. faecalis, S. mutans, S. sanguinis, and P. gingivalis. These bacteria can be eliminated with chlorophenol camphor menthol (ChKM) solution and triple-antibiotic paste (TAP) as an intracanal medicament. This study compared the effectiveness of ChKM solution to triple-antibiotic paste as an intracanal medicament for bacteria that cause a chronic periapical abscess. Methods: An experimental laboratory was conducted in-vitro with the microdilution method and optical density measurement using a spectrophotometer. The cell inhibition percentage was calculated to determine the MIC value. The MBC values were confirmed by cultivating the Mueller Hinton Agar samples, incubating them at 37°C for 24 hours, and observing bacterial growth. Bacteria did not grow in the medium at MBC value. The lower MIC and MBC were sensitive and could be an effective medicament choice. Results: The MIC ChKM solution inhibits E. faecalis ATCC 29212, S. mutans ATCC 25175, S. sanguinis ATCC 10556, and P. gingivalis ATCC 33277 were 4000, 4000, 2000, and 2000 µg/mL consecutively. While MIC of TAP were 6, 0.375, 0.75, and 1.5 µg/mL, respectively. Moreover, MBC of the ChKM solution were 32000, 32000, 8000, 8000 µg/mL and MBC of the TAP were 768, 24, 24, 96 µg/mL. Conclusions: ChKM solution and TAP effectively inhibited and killed E. faecalis, S. mutans, S. sanguinis, and P. gingivalis as an intracanal medicament, as seen from the MIC and MBC values. However, TAP is more effective than the ChKM solution because MIC and MBC values of TAP are much lower than the ChKM solution. This finding indicated that TAP is more effective at the lowest concentration than ChKM solution. It should be highlighted that this was an in-vitro study involving specific microbes; thus, further clinical research is needed.

Liposomes loaded with betel leaf (Piper betle L.) extract: Antibacterial activity and preservative effect in combination with hurdle technologies on tilapia slices

Betel (Piper betle L.) leaf ethanolic extract (BLEE) has shown to possess antibacterial activities. However, the use of BLEE is still limited due to the instability and remaining chlorophylls even after dechlorophyllization. Encapsulation using liposomes might enhance its stability and reduce the color of BLEE, but antibacterial properties of liposomes have not been elucidated. Hence, this study was conducted to determine the antibacterial activity of liposome loaded with BLEE (L/BLEE). Microbial challenge tests using the selected bacteria (Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Shigella sonnei) were also conducted to evaluate the preservative properties of L/BLEE at different concentrations combined with modified atmosphere packaging (MAP) and non-thermal plasma (NTP) treatment on tilapia slices stored at 4 °C. Antibacterial activity of BLEE was enhanced (p < 0.05) after loading into liposomes, as witnessed by lower (p < 0.05) MIC and MBC than those of the unencapsulated BLEE. L/BLEE also showed larger inhibition zones, lower triphenyl-2H tetrazolium chloride (TTC) dehydrogenase activity, and higher release rates of K+ and Mg2+ ions (p < 0.05) of bacteria. Additionally, scanning electron microscopic (SEM) images showed deformations and perforation on cell walls of bacteria after treatment with L/BLEE. L/BLEE at 400 ppm combined with MAP (CO2: Ar: O2 = 60: 30: 10) and NTP (80 KV-RMS for 5 min) exhibited the highest inhibition effect (p < 0.05) toward all the challenged bacteria over 15 days of storage at 4 °C. The use of L/BLEE at 400 ppm combined with MAP and NTP treatments could preserve tilapia slices for up to 12 days.

Conversion of Conservation Reserve Program land back to cropland: Changes in soil carbon and nitrogen dynamics during the first five years

In the United States, Texas has one of the largest areas of land enrolled as well as expiring from the Conservation Reserve Program (CRP), and most of these restored grasslands are in the Southern High Plains region. Crop market forces and agency reductions in the number of hectares that can reenroll in CRP have resulted in many farmers considering recultivating this land. Converting grasslands to conventionally tilled annual croplands could reverse the accumulated benefits afforded from perennial grasslands. Three soil profile depths (0 to 10, 0 to 30, and 0 to 50 cm) from three long-term (&gt;23 years) CRP and three converted CRP (C-CRP) sites were assessed annually from 2012 to 2015 (representing one to five years following conversion). Soil health indicators related to soil carbon (C) and nitrogen (N) dynamics were evaluated including soil organic C (SOC), total N (TN), particulate organic matter C and N (POM-C and POM-N), permanganate oxidizable C (POXC), microbial biomass C and N (MBC and MBN), in situ soil carbon dioxide (CO₂) efflux, and metabolic quotient (<i>q</i>CO₂). Redistribution of C following CRP conversion was detected in the MBC stock in 2012 with values higher in C-CRP than CRP at 0 to 30 cm and 0 to 50 cm profiles but not at 0 to 10 cm. The increase was short-lived with lower MBC in C-CRP than CRP in subsequent years. Most C and N stocks were lower in C-CRP compared to CRP across all depth profiles. The greatest losses of soil C and N stocks occurred at 0 to 10 cm, with the magnitude of loss varying by indicator and soil depth profile. Five years following conversion, SOC was reduced 2.7 Mg ha^–1 at 0 to 10 cm, and averaged across all sample years, SOC was reduced by 4.3 Mg ha^–1 at 0 to 50 cm. Drought stress was present from 2011 to 2014 and exerted an additional pressure to both systems, but the CRP system responded more positively to increased precipitation in 2014 and 2015. In CRP, the <i>q</i>CO₂, an indicator of microbial stress, remained below 1.0 throughout the study, and MBC increased by 81% from 2012 to 2014, when drought stress was lessened. In contrast, MBC decreased and <i>q</i>CO₂ doubled under C-CRP from 2012 to 2014. Overall, this study showed negative impacts on soil C and N stocks within five years after CRP to C-CRP conversion.

Antimicrobial Efficacy of Biogenic Cobalt and Copper Nanoparticles against Pathogenic Isolates.

Biogenic synthesis of cobalt (Co) and copper (Cu) nanoparticles (NPs) was performed using the bacterial strains Escherichia coli and Bacillus subtilis. Prepared NPs were confirmed by a color change to maroon for CoNPs and green for CuNPs. The NPs characterization using FTIR showed the presence of functional groups, i.e., phenols, acids, protein, and aromatics present in the Co and CuNPs. UV-vis spectroscopy of E. coli and B. subtilis CuNPs showed peaks at 550 and 625 nm, respectively. For E. coli and B. subtilis CoNPs, peaks were observed at 300 nm and 350 nm, respectively. Antibacterial and antifungal activity of B. subtilis and E. coli Co and CuNPs was determined at 100 mg/mL concentration against two bacterial strains at 5, 2.5, and 1.5 mg/mL against fungal two strains F. oxysporum and T. viridi, respectively. B. subtilis CuNPs showed significantly higher inhibition zones (ZOI=25.7-29.7 mm) against E. coli and B. subtilis compared to other biogenic NPs. Likewise, B. Subtilis CuNPs showed lower MIC (4.3 ± 6.3) and MBC (5.3 mg/mL) values against both tested isolates. Antifungal activity of B. subtilis and E. coli CuNPs and CoNPs showed a concentration-dependent decrease in ZOI. Among all biogenic NPs, B. subtilis CoNPs showed the highest ZOI (25-30 mm) against F. oxysporum followed by E. coli CuNPs with maximum ZOI (20-27 mm) against T. viridi. Again, B. subtilis CoNPs and E. coli CuNPs showed lowest MIC and MFC values against both fungal isolates. In conclusion, the current study showed that biogenically synthesized B. subtilis Cu or CoNPs can be used as effective antimicrobial agents due to their potential antibacterial and antifungal potential.

Preparation of Nanostructured Lipid Carriers (NLCs) Loading Violacein Extract for Anti-Acne Products

The objective of this research is to evaluate the antimicrobial activity of Nanostructured Lipid Carriers (NLCs) loading violacein extract. The extract was tested for the antimicrobial activities against 3 strains of pathogenic bacteria; namely Cutibacterium acnes ATCC 6919, Staphylococcus aureus ATCC 6538 and Staphylococcus epidermidis ATCC 12228 by agar well diffusion assay. The result indicated that the violacein extract from Chromobacterium violaceum ATCC 12472 has strongest antibacterial effect against C. acnes, S. aureus and S. epidermidis with MIC values in range of 0.0146-0.4688 mg/mL with the lowest MBC value of 0.0146 mg/mL against C. acnes. Violacein extract loaded Nanostructured Lipid Carriers (NLCs) for anti-acne products were prepared by using melt-emulsification technique. The studied factors are the ratio of liquid lipid and solid lipid (LL:SL), surfactant concentration and sonication time. The Ratio of Oleic acid and Compritol® 888 ATO (3:1) with Tween 20 (1.5% w/w) and sonication time of 10 minute (F8 formulation) are an optimizing condition for NLC-Base. The resulted formulations showed the NLC-Base had average particle size of 213.7±2.42 nm with a polydispersity index of 0.239±0.003 and Zeta potential of -26.6±0.45 mV. After that, violacein extract (2% w/w) was loaded into the NLCs (VIO-NLCs). Antibacterial activity of VIO-NLCs 2 % was determined by using agar dilution. The result showed that VIO-NLCs 2 % can inhibit the growth of C. acnes for 60 days during storage. Furthermore, VIO-NLCs 2 % can also act as S. aureus and S. epidermidis inhibitor within 30 days shelf life.

The Impact of Apple Variety and the Production Methods on the Antibacterial Activity of Vinegar Samples.

Apple vinegar is a natural product widely used in food and traditional medicine as it contains many bioactive compounds. The apple variety and production methods are two factors that play a major role in determining the quality of vinegar. Therefore, this study aims to determine the quality of apple vinegar samples from different varieties (Red Delicious, Gala, Golden Delicious, and Starking Delicious) prepared by three methods using small apple pieces, apple juice, and crushed apple, through determining the physicochemical properties and antibacterial activity of these samples. The antibacterial activity was studied against five pathogenic bacteria: Staphylococcus aureus, Klebsiella pneumonia, Escherichia coli (ATB: 57), Escherichia coli (ATB: 97), and Pseudomonas aeruginosa, using two methods, disk diffusion and microdilution, for determining the minimum inhibitory concentrations and the minimum bactericidal concentrations. The results of this study showed that the lowest pH value was 3.6 for Stark Delicious, obtained by liquid fermentation, and the highest acetic acid values were 4.7 and 4% for the vinegar of Red Delicious and Golden Delicious, prepared by solid fermentation, respectively. The results of the antibacterial activity showed considerable activity of apple vinegar on the tested strains. Generally, the Staphylococcus aureus strain appears less sensitive and Pseudomonas aeruginosa seems to be very sensitive against all samples, while the other strains have distinct sensitivities depending on the variety studied and the method used. A higher antibacterial activity was found in vinegar obtained by the apple pieces method and the Red Delicious variety, with a low MIC and MBC recorded, at 1.95 and 3.90 µL/mL, respectively. This study has shown that the choice of both apple variety and production method is therefore an essential step in determining and aiming for the desired quality of apple vinegar.

Evaluation of Antimicrobial Activity of Rhazya Stricta (Apocynaceae) Extract Prepared with Different Solvents on Staphylococcus Aureus (Staphylococcaceae) Isolated from Humans

Introduction: Bacterial resistance to antibiotics, the first major concern in the 1960s, has reappeared worldwide over the past 20 years. Because these bacteria are not resistant to various conventional therapies, the medicinal and herbal plants used in different countries should be evaluated for their therapeutic potential. These valuable biological resources are a repository of complex active molecules. Therefore, in this study, we tried to evaluate the antimicrobial activity of some medicinal plant extracts on Staphylococcus aureus isolated from humans.Methods: Rhazya stricta was collected and their species were identified in the botanical laboratory of University of Zabol. To prepare plant extract, 40 g of dried leaves were used in 400 cc of solvent (aqueous, ethanol, methanol, ethyl acetate, and hydro-alcoholic). The various strains of Staphylococcus aureus used in this study were isolated from the human nose and identified by biochemical, bacteriological and growth tests as well as standard tests. Antimicrobial effects were investigated by well diffusion method in Muller Hinton agar medium. Statistix ver10 software was used for statistical calculations. Mean comparison was performed using the LSD at the level of one percent and Excel software was also used to draw the shapes.Results: Rhazya stricta extracts had different inhibitory zone diameters against Staphylococcus aureus at 100 ppm dilution (p <0.01). R. stricta ethanolic extract had the greatest effect (average 8.3 mm) on inhibiting the growth of 6 strains of S. aureus. Then aqueous and hydroalcoholic extracts with an average of 7 mm were in the next ranks. The ethyl acetate extract had the lowest effect on the inhibition of S. aureus. The lowest MIC of R. stricta ethanolic extract against S. aureus samples was 3.1 ppm, which was inhibited by four strains. The lowest MBC was 6.2 ppm.Conclusion: Considering the side effects of chemical drugs and antibiotics as well as the potential effect of ethanolic extract of Rhazya stricta on Staphylococcus aureus, it is recommended to use ethanol solvent to evaluate the antimicrobial activity of R. stricta.

Cynometra cauliflora L.: An indigenous tropical fruit tree in Malaysia bearing essential oils and their biological activities

Cynometra cauliflora L., locally known as “ nam-nam ” or “ katak puru-puru ” in Malaysia is belonging to the Fabaceae family. The tree is native to Malaysia and has been used traditionally as folk medicine. Limited works have been conducted on C. cauliflora regarding its chemical composition. In view of this, the present study aimed to identify the essential oil (EO) composition of the leaf, twig and fruit of C. cauliflora and evaluate their antioxidant, antimicrobial and cytotoxic activities. EOs obtained from different parts of the tree were analyzed using capillary GC and GC/MS. Twenty-six, seventeen and fifty constituents were identified in the leaf, twig and fruit EOs of C. cauliflora . Results demonstrated the dominance of monoterpenes hydrocarbons in the leaf oil and oxygenated monoterpenes in the twig oil. On the contrary, fruit oil was abundant in oxygenated sesquiterpenes. Different chemical profiles were found in different parts of EOs which have contributed to varied biological activities. Twig oil (IC 50 37.12 ± 2.84 µg/mL) showed better antioxidant power than the leaf (IC 50 207.17 ± 2.95 µg/mL) and fruit oils (IC 50 461.88 ± 12.61 µg/mL) in DPPH assay. Additionally, twig oil inhibited an entire range of microorganisms tested with inhibition zones ranging 10.3 ± 0.4 to 29.7 ± 0.4 mm. The twig oil displayed low MIC and MBC values against Staphylococcus aureus (MIC 125.0 µg/mL; MBC 250.0 µg/mL) and MRSA (MIC 125.0 µg/mL; MBC 250.0 µg/mL). In in vitro MTT assay, twig oil showed anti-proliferative effects against human breast cancer MCF-7 cells.

Enhancement of Antimicrobial and Antiproliferative Activities of Standardized Frankincense Extract Using Optimized Self-Nanoemulsifying Delivery System

Boswellic acids (BAs) are the main bioactive compounds of frankincense, a natural resin obtained from the genus Boswellia. This study aimed to develop a self-nanoemulsifying delivery system (SNEDS) to improve the antimicrobial and antiproliferative activities of standardized frankincense extract (Fr-extract). Fr-extract was standardized, and BA content was quantified using the developed HPLC-UV method. Screening studies of excipients followed by formula optimization using a mixture simplex lattice design was employed. The optimized Fr-SENDS formulation was characterized. Furthermore, microbiological and antiproliferative assessments of the standardized Fr-extract and Fr-SNEDS were evaluated. Quantification demonstrated that the major constituent is 11-keto-boswellic acid (KBA) (16.25%) among BA content (44.96%). The optimized Fr-SENDS (composed of 5% CapryolTM 90, 48.7% Gelucire® 44/14 and 46.3% ethanol) showed spherical nanosized dispersions with DS, PDI, and zeta potential of 17.9 nm, 0.2, and −14.5 mV, respectively. Fr-SNEDS exhibited lower MIC and MBC values compared with Fr-extract against pathogens conjugated with lung cancer and was comparable to reference antimicrobials. Fr-SNEDS showed superior antiproliferative activity over Fr-extract, with IC50 values of 20.49 and 109.5 μg mL−1, respectively. In conclusion, the optimized Fr-SNEDS could be easily developed and manufactured at a low cost and the in vitro results support its use as a potential adjuvant oral therapy for lung cancer. Further in vivo studies could be continued to assess the therapeutic efficiency of the prepared system.

MICROBIAL SYNTHESIS OF SILVER NANOPARTICLES USING STREPTOMYCES SP. PG12 AND THEIR CHARACTERIZATION, ANTIMICROBIAL ACTIVITY AND CYTOTOXICITY ASSESSMENT AGAINST HUMAN LUNG (A549) AND BREAST (MCF-7) CANCER CELL LINES

Objective: Synthesis of silver nanoparticles using Streptomyces sp. PG12 and their characterization, antimicrobial activity and cytotoxicity against A549 and MCF-7 cancer cell lines. Methods: The silver nanoparticles were subjected to UV-Vis. spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS), high-resolution transmission electron microscopy (HR-TEM), zeta potential, and X-ray diffractometry (XRD) analyses. Further, the antimicrobial potential was determined by using the agar well diffusion method and cytotoxicity was determined with the help of cell viability (MTT) assay and reactive oxygen species (ROS) assay. Results: The initial indication of silver nanoparticles synthesis was noticed by the colour change in the reaction mixture and the absorption maximum at 421 nm in UV-Vis. analysis; whereas, the FTIR analysis displayed the biological functional groups responsible for the capping and stabilization of silver nanoparticles. SEM and TEM micrographs revealed the surface morphology, spherical shape, and smallest particle size as 18.91 nm. The EDS and XRD patterns confirmed the involvement of various elements during the synthesis of silver nanoparticles and the crystalline, face-centered cubic nature, respectively. The silver nanoparticles displayed considerable antimicrobial activity against human pathogens even at low MIC and MBC concentrations and exhibited increased anticancer activity against A549 and MCF-7 cell lines, where the ability of silver nanoparticles to significantly restrict the growth of tumour cells was observed at IC50 values of 69.04µg/ml and 138.30µg/ml, respectively. Conclusion: Streptomyces sp. PG12 synthesized silver nanoparticles show significant anticancer activity against A549 and MCF-7 cell lines.

Tests of biocides and H2S scavengers as additives to drilling muds and fracturing fluids

The article presents the results of studies on substances with a biocidal effect in terms of their possible use as additives to drilling muds and fracturing fluids. The aim of the work was to identify the most effective biocides by examining their action on aerobic and anaerobic bacteria, fungi, sulfate-reducing bacteria (SRB), and a consortium of microorganisms. Various chemicals have been considered, due to a constant and overriding goal to find the one with the highest activity, and above all, the ones that have not yet been tested. Particular attention was paid to substances that, apart from known biocidal properties, have also the ability to neutralize hydrogen sulfide, and to reduced sulfur compounds (H2S scavengers), and the so-called “green biocides”, i.e. those that are considered safe for the environment. Most of the tested biocidal agents were effective against aerobic and anaerobic bacteria, while 10 out of 12 showed good or very good activity against SRB (low MIC and MBC values), including 3 out of 4 H2S scavengers. On the other hand, only some biocidal agents proved to be effective against fungi and microbial consortium; among them were agents containing quaternary ammonium compounds (Bardac LF and Barquat CB-80), triazine derivatives (Biostat and Petrosweet HSW 82165) and DBNPA (Biopol C-103L). Bardac LF and Barquat CB-80, together with the mixture of Grotan OX and Preventol GDA 50, upon introduction to the drilling mud and fracturing fluid, were superior over other biocidal agents (Biostat, Petrosweet HSW 82165 and Biopol C-103L), showing the full activity at 800 ppm. Environmentally friendly biocide Aquacar THPS 75 appeared to be the least effective.

Optimization of the microwave assisted extraction and biological activities of polyphenols from lemon verbena leaves

The present study aims to optimize the extraction of phenolics by microwave-assisted extraction (MAE) using the response surface methodology (RSM), from Lemon verbena leaves. The optimized extract was tested for its antioxidant activity using two methods (DPPH and reducing power) and its antibacterial efficiency by using disk diffusion assay and broth microdilution, against two Gram-negative (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853) and two Gram-positive (Staphylococcus aureus ATCC 25923, Bacillus subtilis ATCC 6633) strains. Under the optimized conditions (40% (v/v): of ethanol concentration, 188 s of irradiation time, 600 W of microwave power and 1:40 g/mL of solid-to-liquid ratio) the total phenolic content (TPC) was 67.87±1.61 mg GAE/g DW. The IC50 of the extract was 139.65±1.44 µg/mL and 56.60±2.79 µg/mL for DPPH inhibition and reducing power, respectively. The best antibacterial activity was shown by the extract obtained by MAE with lower MBC (1.56 to 18.75 mg/mL) and MBC/MIC ratio. Lemon verbena extract can be used as an ingredient in cosmetics, food supplements and herbal medicinal products due to its interesting biological properties.

Sulfamethoxazole-phytochemical hybrid: A novel approach in current antibacterial drug development

Background: The Gram-positive (GP) bacterium, methicillin-resistant Staphylococcus aureus (MRSA) causes common infection, bacteremia at hospitals, and community sectors, with the simultaneous aggrandizement of resistance to several currently used antibacterials, resulting in additional morbidity and unexpected mortality. Since the last several decades, thousands of phytochemicals with antimicrobial potency have been recorded as alternate antibacterial agents; but, none of those have gone up to the pure-drug stage due to the lack of the desired drug-likeness values and the required pharmacokinetic properties. However, chemical modification of parent drug remains as the versatile approach in antibacterial drug development. Methods and materials: Based on the structural suitability of sulfamethoxazole (SMZ) and as a solution towards control of MRSA, proposed six new ‘SMZ-phytochemical’ hybrid entities followed by protocol of azo-coupling synthesis. PASS prediction, Lipinski rules of five, lethal-dose value, toxicity class, and molecular docking-simulation were employed before chemical synthesis. Due to the unavailability of the three-dimensional (3D) structure of the suitable target enzyme, MRSA-dihydropteroate synthases (DHPS), the 3D model of MRSA-DHPS was generated and validated by the Ramachandran plot for molecular docking-simulations study with designed hybrids. Based on the above computational analyses, the most effective hybrid, ‘SMZ-thymol,’ was synthesized and characterized by advanced spectral techniques such as UV, FTIR, LCMS, HPLC, NMR, and SEM. The zone of inhibition, MIC, and MBC values of the hybrid had determined against isolated MRSA strain from clinical samples, in vitro. Results: The synthesized ‘SMZ-thymol’ hybrid had the highest zone size inhibition on agar plates with 20 and 40 μg/mL as the lowest MIC and MBC values against MRSA, respectively, while the reference antibiotic ampicillin had the lower MIC and MBC values at 80 to 180 μg/mL. Additionally, from in vitro host-toxicity testing with cultured human lymphocytes from umbilical cord blood confirmed that the synthesized hybrid had broadly, non-toxic to human cells. Conclusion: Thus, newly synthesized ‘SMZ-thymol’ could be promoted as a newer antibacterial agent against gruesome MRSA and other MDR pathogenic bacteria. Indeed, the utilization of inactive antibacterials through suitable phytochemicals in the current antibacterial drug development module could be a prudent time-killing drug development approach using tools of medicinal chemistry and bioinformatics.

ANTI-CARIOGENIC POTENTIALS OF VITEX NEGUNDO LINN

Vitex negundo Linn. (Verbenaceae), is an ethnobotanical important shrub carrying a large array of pharmacologically active phytochemicals with diverse medicinal properties. Present study assessed the antibacterial activities of leaf and twig (without leaf) bioactives against common oral bacterial inhabitants viz., Staphylococcus aureus, Streptococcus oralis, Streptococcus gordonii, Streptococcus mutans, Lactobacillus brevis and Lactobacillus casei. Leaf and twig dried powdered samples of V. negundo were separately fractionated by five solvents in eluotropic series namely petroleum-ether, chloroform, absolute-ethanol, 80%-methanol and distilled-water. Extracts were further analyzed for total phenolic contents (TPC), flavonoids (TFC), tannins, alkaloids and terpenoids. Zone of inhibition, MIC, MBC and IC50 values of the fractionated extracts against oral bacterial pathogens were determined. The results demonstrated significantly higher antibacterial activity in ethanolic extracts (VnLEt) and chloroform (VnLCh) extracts of leaves as evident by their higher ZOI and lower MIC, MBC and IC50 values. VnLEt extracts showed bactericidal effects against all the tested six bacterial pathogens (L. casei&gt;St. gordonii&gt;Staphylococcus aureus&gt;L. brevis&gt;St. oralis=St. mutans). VnLCh showed notable bactericidal effects against five pathogens (L. casei&gt;St. mutans&gt;St. gordonii&gt;Staphylococcus aureus) but remained ineffective against St. oralis and L. brevis. Among twig extracts, ethanolic extracts showed inhibition against Staphylococcus aureus, St. gordonii and St. mutans while chloroform extracts showed antibacterial effect only against Staphylococcus aureus. VnLEt extract showed abundance in TPC, TFC and tannins while VnLCh was rich in alkaloids and terpenoid suggesting their contribution in bactericidal effects against cariogenic bacterial pathogens. Hence, the present study successfully established V. negundo leaf extracts as an excellent natural remedy for oral-dental infections.

Characterization of Streptomyces Isolates Associated with Estuarine Fish Chanos chanos and Profiling of Their Antibacterial Metabolites-Crude-Extract.

Streptomyces has been reported as an essential producer of bioactive substances, including antibiotics and other types of antimicrobials. This study investigated antibacterial-producing Streptomyces isolated from the gut of estuarine fish Chanos chanos, emphasizing screening for the producer of peptide-containing antibacterial compounds. Eighteen isolates were found during preliminary screening, in which four isolates showed the best antibacterial activities. Based on the morphological, physiological, and biochemical characterization, as well as 16S rRNA partial sequencing, all of the four isolates belonged to Streptomyces. Three isolates were suspected as novel isolate candidates based on homology presentations and phylogenetic tree analysis. Disk-diffusion assay of the metabolite-crude-extract from the isolates showed broad-spectrum inhibitory activities against Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 10876, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa InaCC B52 with minimum inhibitory concentration and minimum bactericidal concentration ranging from 2.5–10 mg/mL and 5–10 mg/mL, respectively. The highest antibacterial activity with low MIC and MBC values was shown by isolate AIA-10. Qualitative HPLC profiling revealed that the metabolic-crude-extracts showed many peaks with intensive area at 210 and 214 nm, especially from SCA-11 and AIA-10, indicating the presence of peptide groups in the structure of the constituent compound. The results also suggested that crude extracts SCA-11 and AIA-10 had higher hydrophobicity properties than the other extracts. Further characterization of the active compound was needed to find out which compounds were responsible for the antibacterial activity. The results of this study indicated that some Streptomyces isolated from new environmental niches, i.e., gut of estuarine fish Chanos chanos, produce promising peptide-containing bioactive compounds.

Biological soil crusts enhance moisture and nutrients in the upper rooting zone of sandy soil agroecosystems

AbstractBackground: Biological soil crusts (biocrusts) are commonly found in arid ecosystems and are known to have increased carbon (C) and nitrogen (N) concentrations compared to non‐crusted soil. Similar biocrusts were recently identified in Florida, USA sandy soil agroecosystems where they could impact soil biogeochemical cycling, particularly of C and N, in the crop rooting zone.Aims: Therefore, this research assessed the impacts of biocrusts on soil moisture, available and microbial C and N concentrations, and soil stable N isotopic ratios (δ15N) in the upper rooting zone (0–15 cm) below biocrusts compared to nearby control bare soils without biocrusts.Methods: Intact soil cores (0–15 cm) were collected from crusted and non‐crusted (control) locations in three sandy soil, citrus agroecosystems. Soil cores were partitioned into three depths: a surface (0–1 cm), a middle (1–5 cm), and a subsurface depth (5–15 cm), and were analyzed for soil moisture and multiple C and N cycling pools.Results: Biocrust presence and sampling depth (0–1 cm, 1–5 cm, and 5–15 cm) had significant impacts on soil physical, chemical, and biological parameters at the sites. All sites had increased bulk total C and total N, soluble (ammonium, nitrate, dissolved organic N, and salt extractable C), and microbial (microbial biomass C/N) C and N concentrations in the biocrust surface depth compared to the control without biocrusts. Nitrate and total inorganic N (ammonium + nitrate) were enriched below biocrusts (1–5 cm) with one site having 96% and 71% more nitrate and total inorganic N, respectively, under biocrusts compared to controls. This additional plant‐available N was likely provided by the biocrust, as indicated by the δ15N. Further, the soil below biocrusts (1–5 cm) at one agroecosystem had 44% more microbial biomass C and a significantly lower MBC:MBN than soil without biocrusts.Conclusions: Overall, results illustrate these naturally occurring biocrusts have the potential to benefit agroecosystems by enriching soil C and N in the crop rooting zone, indicating the potential for biocrusts to effect overall soil quality and health.

Novel phenethylimidazolium based ionic liquids: Design, microwave synthesis, in-silico, modeling and biological evaluation studies

An eco-friendly preparation method for the novel bioactive imidazolium ionic liquids halides (ILs) was developed under microwave-assisted conditions. Synthesized ILs were characterized by spectroscopic techniques. Selected ILs were investigated for their antimicrobial activity against highly resistant Gram-positive and Gram-negative bacterial strains. Overall, 3-(2-chlorobenzyl)-1-phenethyl-1H-imidazol-3-iumchloride (4) showed high antimicrobial activity against the Staphylococcus aureus strain in the inhibition zone tests and displayed low MIC and MBC levels against almost all tested bacteria. Furthermore, the ILs were screened in vitro against human hepatocellular carcinoma (HepG-2), human breast adenocarcinoma (MCF-7), and human colon carcinoma (Caco-2) cell lines. The screening results showed excellent to moderate anticancer activity across the ILs. Among the synthesized ILs, Overall, 3-(2-chlorobenzyl)-1-phenethyl-1H-imidazol-3-ium chloride (4) and 1-phenethyl-3-(3-phenoxypropyl)-1H-imidazol-3-ium bromide (7) were found to exhibit the most promising ant proliferative effects and had the lowest IC50 values. The docking study suggested strong interaction of ILs with DNA with binding energy ranging from −4.9 to −4.1 kcal/mol. ILs 4 and 7 were most strongly bonded with −4.9 and −4.8 kcal/mol binding energy; confirming in vitro anticancer results.

Functional microbial diversity responses to biodynamic management in Burgundian vineyard soils

ABSTRACT An on-vineyard approach was used to investigate the effects of biodynamic (BD) preparations on soil microbial biomass and microbial functional diversity in five vineyards on calcareous bedrocks under organic management. The vineyards formed two groups according to soil type; Cambic Leptosols (A1, A2, and B) and Calcaric Leptosols (C1, C2) as well as two groups according to duration of BD application; 16 years (A1 and A2) and 1–3 years (B, C1, and C2). The two Calcaric Leptosols contained on average 65% more microbial biomass C, 110% more microbial biomass N, 70% more ergosterol and exhibited a 45% higher basal respiration rate than the three Cambic Leptosols. The vineyards had, on average, 11% lower MB-C:N ratios in the treatments with the BD addition (BD+) than in those without (BD-). Most substrates induced the highest respiratory responses at vineyards A1 and A2 and the lowest at vineyard C2. Averaging the 17 substrates of the multi-substrate-induced respiration (MSIR) approach, the mean respiratory response was approximately 20% lower in the BD+ treatment at vineyard A1 in comparison with the BD- treatment, but 33% higher at vineyard C2. The differences between the BD treatments in the induced respiration rate for individual substrates were significant for 12 substrates at vineyard A1 and for 5 substrates at vineyard C2. The lower the respiratory response, the higher was the anabolic demand for a specific MSIR substrate. More vineyards should be analysed to differentiate between the effects of soil type and duration of BD application.

The Antibacterial Effects of the Different Extracts of Oenothera biennis and Origanum minutiflorum O. Schwarz et. P. H. Davis on Food-borne Pathogenic Bacteria

This study aimed to determine the antibacterial effects of Oenothera biennis and Origanum minutiflorum O. Schwarz et. P. H. the leaves extrats on foodborne pathogenic bacteria. The highest antibacterial effect on bacterial strains, the lowest Minimum Inhibitory Concentration (MIC) and the lowest Bactericidal Concentration (MBC) values of both plants was determined in extracts obtained from the leaves using diethyl ether (P 500 mg/mL, respectively, in acetone extract detected on Pseudomonas aeroginosa . The lowest MIC value of the diethyl extract of Origanum minutiflorum O. Schwarz et. P. H. Davis was determined to be 0.029 mg/L on Listeria monocytogenes and Bacillus cereus whereas the lowest MBC was determined to be 7.81 mg/mL on Bacillus cereus .