Staphylococcus aureus is a major human pathogen that is responsible for both hospital- and community-acquired infections. Stilbenes are polyphenol compounds of plant origin known to possess a variety of pharmacological properties, such as antibacterial, antiviral, and antifungal effects. This study reports the in vitro growth-inhibitory potential of eight naturally occurring stilbenes against six standard strains and two clinical isolates of S. aureus, using a broth microdilution method, and expressing the results as minimum inhibitory concentrations (MICs). Pterostilbene (MICs = 32-128 μg/ml), piceatannol (MICs = 64-256 μg/ml), and pinostilbene (MICs = 128 μg/ml) are among the active compounds that possess the strongest activity against all microorganisms tested, followed by 3'-hydroxypterostilbene, isorhapontigenin, oxyresveratrol, and rhapontigenin with MICs 128-256 μg/ml. Resveratrol (MIC = 256 μg/ml) exhibited only weak inhibitory effect. Furthermore, structure-activity relationships were studied. Hydroxyl groups at ortho-position (B-3' and -4') played crucial roles for the inhibitory effect of hydroxystilbene piceatannol. Compounds with methoxy groups at ring A (3'-hydroxypterostilbene, pinostilbene, and pterostilbene) produced stronger effect against S. aureus than their analogues (isorhapontigenin and rhapontigenin) with methoxy groups at ring B. These findings provide arguments for further investigation of stilbenes as prospective leading structures for development of novel antistaphylococcal agents for topical treatment of skin infections.
- Klíčová slova
- antimicrobial activity, minimum inhibitory concentration, natural antibacterial agents, structure–activity relationships,
- MeSH
- antibakteriální látky chemie farmakologie MeSH
- fytonutrienty chemie farmakologie MeSH
- lidé MeSH
- mikrobiální testy citlivosti MeSH
- stafylokokové infekce mikrobiologie MeSH
- Staphylococcus aureus účinky léků izolace a purifikace MeSH
- stilbeny chemie farmakologie MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- antibakteriální látky MeSH
- fytonutrienty MeSH
- stilbeny MeSH
Adhesion of gut bacteria to the intestinal epithelium is the first step in their colonization of the neonatal immature gut. Bacterial colonization of the infant gut is influenced by several factors, of which the most important are the mode of delivery and breast-feeding. Breast-fed infants ingest several grams of human milk oligosaccharides (HMOs) per day, which can become receptor decoys for intestinal bacteria. The most abundant intestinal bacteria in vaginally delivered infants are bifidobacteria, whereas infants born by cesarean section are colonized by clostridia. The influence of HMOs on the adhesion of five strains of intestinal bacteria (three bifidobacterial strains and two clostridial strains) to mucus-secreting and non-mucus-secreting human epithelial cells was investigated. Bifidobacterium bifidum 1 and Bifidobacterium longum displayed almost the same level of adhesion in the presence and absence of HMOs. By contrast, adhesion of Clostridium butyricum 1 and 2 decreased from 14.41% to 6.72% and from 41.54% to 30.91%, respectively, in the presence of HMOs. The results of this study indicate that HMOs affect bacterial adhesion and are an important factor influencing bacterial colonization of the gut. Adhesion of the tested bacteria correlates with their ability to autoaggregate.
- Klíčová slova
- autoaggregation, bifidobacteria, cell lines, clostridia, human milk oligosaccharides,
- MeSH
- bakteriální adheze * MeSH
- Bifidobacterium genetika izolace a purifikace fyziologie MeSH
- buněčné linie MeSH
- Clostridium genetika izolace a purifikace fyziologie MeSH
- dospělí MeSH
- feces mikrobiologie MeSH
- kojenec MeSH
- lidé MeSH
- mateřské mléko chemie MeSH
- oligosacharidy metabolismus MeSH
- střeva mikrobiologie MeSH
- střevní mikroflóra MeSH
- střevní sliznice metabolismus MeSH
- Check Tag
- dospělí MeSH
- kojenec MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- oligosacharidy MeSH
Francisella tularensis is a highly virulent intracellular pathogen with the capacity to infect a variety of hosts including humans. One of the most important proteins involved in F. tularensis virulence and pathogenesis is the protein DsbA. This protein is annotated as a lipoprotein with disulfide oxidoreductase/isomerase activity. Therefore, its interactions with different substrates, including probable virulence factors, to assist in their proper folding are anticipated. We aimed to use the immunopurification approach to find DsbA (gene locus FTS_1067) interacting partners in F. tularensis subsp. holarctica strain FSC200 and compare the identified substrates with proteins which were found in our previous comparative proteome analysis. As a result of our work two FTS_1067 substrates, D-alanyl-D-alanine carboxypeptidase family protein and HlyD family secretion protein, were identified. Bacterial two-hybrid systems were further used to test their relevance in confirming FTS_1067 protein interactions.
- Klíčová slova
- FTS_1067 protein, Francisella tularensis, bacterial two-hybrid assay, immunopurification,
- MeSH
- bakteriální proteiny genetika metabolismus MeSH
- faktory virulence genetika metabolismus MeSH
- Francisella tularensis genetika metabolismus patogenita MeSH
- lipoproteiny genetika metabolismus MeSH
- vazba proteinů MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- bakteriální proteiny MeSH
- faktory virulence MeSH
- lipoproteiny MeSH
Epifluorescent microscopy was employed to compare the bacterial live counts (BC) in the gut of two earthworm species Aporrectodea caliginosa and Lumbricus rubellus, representing different ecophysiological groups. The average number of BC was 10.9 x 10(9) g-1 dry weight in the gut of A. caliginosa, 5.9 x 10(9) in that of L. rubellus, 8.1 x 10(9) in earthworm casts and 6.0 x 10(9) in the soil. The number of BC showed a great seasonal variability in all the materials studied, exhibiting maxima in spring and autumn, and a minimum in summer. The BC increased in number during the passage of food material through the gut of both L. rubellus and A. caliginosa. The difference between BC in fore-gut and hind-gut were significantly higher in L. rubellus (4.2 x 10(9) vs. 8.8 x 10(9)) than that in A. caliginosa (10.3 x 10(9) vs. 13.4 x 10(9)). Interspecific differences in the number of BC may result from the different chemical and microbiological composition of the material consumed by earthworms as related to different feeding habits of both species.
- MeSH
- Bacteria izolace a purifikace ultrastruktura MeSH
- fluorescenční mikroskopie MeSH
- Oligochaeta klasifikace mikrobiologie MeSH
- půdní mikrobiologie MeSH
- roční období MeSH
- stravovací zvyklosti MeSH
- střeva mikrobiologie MeSH
- trávení MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Gut content sections of the earthworm Lumbricus rubellus, the surrounding soil and casts were studied using transmission electron microscopy. Bacteria, actinomycetes, dead fungi and empty mycelia were observed to occur throughout the gut content. In the foregut and midgut of worms, some bacteria were found to be partially or totally lysed and digested, although were protected by polysaccharides and clay particles. Not only inactive resting forms (spores) or cells protected by capsular polysaccharides and clay particles and/or by plant cellular remnants, but also separate metabolically active and dividing cells were recovered especially in hindgut. The formation of new bacterial microaggregates was noticed in the posterior intestine as well.
- MeSH
- Bacteria ultrastruktura MeSH
- Oligochaeta mikrobiologie ultrastruktura MeSH
- půdní mikrobiologie MeSH
- střeva mikrobiologie ultrastruktura MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
