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Thin-layer chromatography—direct bioautography (TLC—DB) followed by liquid chromatography—tandem mass spectrometry (LC—MS/MS) was used for screening and tentative identification of the antibacterial constituents of Salvia officinalis L. ethanol extract. Seven bacterial strains were used as test organisms, both pathogenic and nonpathogenic, that is, Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Staphylococcus epidermidis, Micrococcus luteus, Bacillus subtilis, luminescence gene-tagged Pseudomonas syringae pv. maculicola, and naturally luminescent marine bacterium Aliivibrio fischeri. Eight fractions with the widest antimicrobial spectrum were detected using TLC—DB, isolated by semi-preparative TLC, and subjected to LC—MS/MS analyses. Finally, five bioactive components were tentatively identified, based on their fragmentation pattern, such as salvigenin, cirsimaritin, rosmanol, carnosic acid, and 12-O-methyl carnosic acid.

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The antibacterial effect of the components of clary sage (Salvia sclarea L.) and spearmint (Mentha spicata L. var. crispa (Bentham) Danert) was investigated by means of high-performance thin-layer chromatography-direct bioautography against the Gram-positive soil bacterium Bacillus subtilis (Bs) and Gram-negative bacteria such as a pepper pathogen Xanthomonas euvesicatoria (Xe), a luminescence gene-tagged Arabidopsis pathogen Pseudomonas syringae pv. maculicola (Psm) and a luminescent marine Aliivibrio fischeri (Af). Sclareol, linalool, and linalyl acetate were identified as active components of clary sage and carvone as the antibacterial substance in spearmint. Sclareol inhibited all tested bacteria, linalool and carvone showed antibacterial effect against all Gram-negative strains tested, while linalyl acetate only against Xe and Af. Some minor components of the clary sage essential oil also gave a zone of inhibition when tested on Gram-negative bacterium strains.

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Coffee, due to its common consumption, is one of the main sources of polyphenols in human diet. Coffee species and coffee-related products differ in composition and content of main components, such as chlorogenic acid and caffeine. Chemical and biological fingerprints of various Coffea arabica L. extracts were obtained in order to check and compare their antibacterial and antioxidant properties. The antibacterial activity of green and roasted coffee seeds and pomace was evaluated against Bacillus subtilis using thin-layer chromatography (TLC)-direct bioautography. TLC-2,2-diphenyl-1-picrylhydrazyl (DPPH) test was used to determine antioxidant properties of the afore-mentioned extracts. Furthermore, different solvents and several extraction methods such as simple maceration, maceration under stirring, and ultrasonic accelerated extraction were tested. The most efficient method of extraction of caffeine and chlorogenic acid was chosen based on quantitative TLC analysis. Additionally, these two main components of coffee were quantitatively determined in commercial products of green coffee.

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A method was developed for effect-directed analysis (EDA) of the root extract of Pimpinella saxifraga L. High-performance thin-layer chromatography (HPTLC) was hyphenated with microchemical, biochemical, and biological assays as well as electrospray ionization– mass spectrometry (ESI–MS). This HPTLC–UV/Vis/FLD– EDA–MS method directly pointed to multi-potent compounds in the P. saxifraga L. root extract. 2,2-Diphenyl-1-picrylhydrazyl radical scavengers, acetylcholinesterase inhibitors, estrogen-effective compounds, antimicrobials against Gram-positive Bacillus subtilis bacteria, and Gram-negative Aliivibrio fischeri bacteria were discovered in the root extract. A first targeted characterization of four unknown multi-potent compounds was performed by HPTLC–ESI–MS and microchemical derivatizations. This highly streamlined effect-directed profiling is recommended for a fast and cost-efficient natural product search.

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In this study, the antibacterial profiling of the ethanolic leaf extract of greater burdock (Arctium lappa L.) is demonstrated, applying thin-layer chromatography (TLC) coupled bioassays against the Gram-positive soil bacterium Bacillus subtilis and the Gram-negative pepper pathogen Pseudomonas syringae pv. maculicola. The main active component was isolated by eluting from the adsorbent bed and subjected to a targeted characterization by high-performance liquid chromatography–diode array detection–electrospray ionisation–mass spectrometry. The identification of the germacranolide sesquiterpene lactone onopordopicrin was based on its retardation factor, bioactivity in TLC-based methods, and retention tim as well as ultraviolet (UV) and mass spectra, compared to those of the reference substance isolated earlier in our laboratory from Onopordum acanthium leaf.

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European Journal of Microbiology and Immunology
Authors:
Usman Ali Khan
,
Dr. Hazir Rahman
,
Zeeshan Niaz
,
Muhammad Qasim
,
Jafar Khan
,
Tayyaba
, and
Bushra Rehman

Abstract

Medicinal plants are traditionally used for the treatment of human infections. The present study was undertaken to investigate Bergenia ciliata, Jasminum officinale, and Santalum album for their potential activity against human bacterial pathogens.

B. ciliata, J. officinale, and S. album extracts were prepared in cold and hot water. The activity of plant extracts and selected antibiotics was evaluated against five bacterial pathogens including Staphylococcus aureus, Bacillus subtilis, Proteus vulgaris, Pseudomonas aeruginosa, and Escherichia coli using agar well diffusion method.

Among the three medicinal plants, B. ciliata extracts displayed potential activity against bacterial pathogens. Cold water extract of Bergenia ciliate showed the highest activity against B. subtilis, which is comparable with a zone of inhibition exhibited by ceftriaxone and erythromycin. J. officinale and S. album extracts demonstrated variable antibacterial activity. Further studies are needed to explore the novel antibacterial bioactive molecules.

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Quorum sensing (QS) is the chemical communication processes between bacteria, which may be inter-genus or intra-genus. In general, several physiological functions, such as nutrient uptake, competence development, biofilm formation, sporulation, and toxin secretion, are accomplished through QS process. The QS (cell density-dependent process) circuit in Gram-positive bacteria consists mainly of two parts: an inducer molecule and a receptor protein. The binding of inducer molecule to receptor activates the target gene, which then performs the necessary function in bacteria. In the past few years, several investigations have been conducted to explore the QS circuit in various bacteria, but still this information is insufficient to fully understand the bacterial gene expression cascade. In the present review, we summarize the QS architecture and their associated gene regulation in four Gram-positive bacteria, such as Bacillus subtilis, Staphylococcus aureus, Bacillus cereus, and Streptococcus pneumoniae. It is well established that S. aureus, B. cereus, and S. pneumoniae are potent human pathogen. A detailed understanding of QS circuit in these bacteria would be useful in preparation of customized medicine in future. Whereas, B. subtilis is an industrially important candidate and has been used in several biotechnology sectors. Understanding of QS circuit in B. subtilis will definitely enrich the antibiotics and enzyme industries.

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Acta Veterinaria Hungarica
Authors:
Orsolya Erdősi
,
Katalin Szakmár
,
Olivér Reichart
,
Zsuzsanna Szili
,
Noémi László
,
Péter Székely Körmöczy
, and
Péter Laczay

The incidence of outbreaks of foodborne listeriosis has indicated the need for a reliable and rapid detection of the microbe in different foodstuffs. A method combining redox potential measurement and real-time polymerase chain reaction (PCR) was developed to detect Listeria monocytogenes in artificially contaminated raw milk and soft cheese. Food samples of 25 g or 25 ml were homogenised in 225 ml of Listeria Enrichment Broth (LEB) with Oxford supplement, and the redox potential measurement technique was applied. For Listeria species the measuring time was maximum 34 h. The absence of L. monocytogenes could reliably be proven by the redox potential measurement method, but Listeria innocua and Bacillus subtilis could not be differentiated from L. monocytogenes on the basis of the redox curves. The presence of L. monocytogenes had to be confirmed by real-time PCR. The combination of these two methods proved to detect < 10 cfu/g of L. monocytogenes in a cost- and time-effective manner. This method can potentially be used as an alternative to the standard nutrient method for the rapid detection of L. monocytogenes in food.

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Journal of Thermal Analysis and Calorimetry
Authors:
Mihaela Badea
,
Rodica Olar
,
Dana Marinescu
,
Veronica Lazar
,
Carmen Chifiriuc
, and
Gina Vasile

Abstract  

This paper reports the investigation on the thermal stability of new complexes with mixed ligands of the type [Cd(NN)(C3H3O2)2(H2O)m]·nH2O [(1) NN: 1,10-phenantroline, m = 1, n = 0; (2) NN: 2,2′-bipyridine, m = 0, n = 1.5 and (C3H3O2): acrylate anion]. The IR data indicate a bidentate coordination mode for both heterocyclic amine and acrylate. The in vitro qualitative and quantitative antimicrobial activity assays showed that the complexes exhibited variable antimicrobial activity against planktonic as well as biofilm embedded Gram-negative (Escherichia coli, Klebsiella sp., Proteus sp., Salmonella sp., Shigella sp., Acinetobacter boumani, Pseudomonas aeruginosa), Gram-positive (Bacillus subtilis, Staphylococcus aureus) and fungal (Candida albicans) strains, reference and isolated ones from the hospital environment. The thermal behaviour steps were investigated in synthetic air flow. The thermal transformations are complex processes according to TG and DTA curves including dehydration, amine as well as acrylate thermolysis. The final products of decomposition are the most stable metal oxides.

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Application of microcalorimetry and chemometric analysis

Effects evaluation of angle and nail animal drugs on Bacillus subtilis growth

Journal of Thermal Analysis and Calorimetry
Authors:
Xiaoyan Xing
,
Yanling Zhao
,
Weijun Kong
,
Yanwei Zhong
,
Dan Yan
,
Ping Zhang
,
Yumei Han
,
Lei Jia
,
Cheng Jin
, and
Xiaohe Xiao

Abstract

In this study, microcalorimetry combined with chemometric analysis was used to investigate the effects of angle and nail animal valuable drugs on Bacillus subtilis (B. subtilis) growth. The power–time curves of the growth metabolism of B. subtilis affected by Cornu Cervi Pantotrichum, Cornu Cervi Elaphi, Cornu Saigae Tataricae, cornu caprae hircus, Cornu Bubali, Squama Manis, and Carapax Trionycis were determined using a thermal activity monitor (TAM) air isothermal microcalorimeter, ampoule mode, at 37 °C. By analyzing these curves and some quantitative parameters using principal component analysis, the effects of the seven animal drugs on B. subtilis could be quickly evaluated from the change of the two main parameters, the maximum heat-flow power P m 2 and total heat output Q t: Cornu Saigae Tataricae, cornu caprae hircus, Cornu Bubali, Squama Manis, and Carapax Trionycis inhibited the growth of B. subtilis, while Cornu Cervi Pantotrichum and Cornu Cervi Elaphi promoted the growth of B. subtilis. Further, the result of hierarchical clustering analysis showed that the drugs which promoted the growth of B. subtilis gathered in one cluster, the other drugs which inhibited the growth of B. subtilis gathered in the other cluster. All these illustrated that the internal characteristics of the seven animal drugs were different though they had similar resources and these drugs could be well clustered according the effects of them on B. subtilis growth with the help of chemometric methods. This study provided an useful idea of the combination of microcalorimetry and chemometric analysis for studying the effects of drugs on organisms.

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