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Sledovali sme potlačenie bakteriálneho rastu siedmich kmeňov Acinetohacter spp. po 30 min účinku tobramycínu v suprainhibičných koncentráciách (postantibiotický účinok - PAE) a v supra-subinhibičných koncentráciách (postantibiotický účinok subinhibičných koncentrácií - PA SME) ako aj zmeny v povrchovej hydrofobicite, v produkcii lipázy a histamínu u týchto exponovaných kmeňov. Sledované farmakodynamické parametre (PAE a PA SME) ako aj zmeny v testovaných vlastnostiach Študovaných kmeňov boli závislé na koncentrácii antibiotika a na kmeni. Potlačenie bakteriálneho rastu po účinku tobramycínu v koncentrácii 2x MIC sa pohybovalo v rozsahu od 0,6-4,5 h, vyššia koncentrácia (4x MIC) indukovala dlhšie PAE (1,9-5,4 h). Tobramycín v supra-subinhibičných koncentráciách (2x MIC + 0,2x MIC a 4x MIC + 0,2x MIC) spôsobil úplnú supresiu bakteriálneho rastu. U väčšiny testovaných kmeňov sa po účinku tobramycínu zistilo zvýšenie hydrofobicity hodnotenej adherenciou baktérií na xylén, ako aj zvýšenie lipolytickej aktivity. Tobramycín v testovaných koncentráciách neovplyvnil produkciu histamínu.
Suppression of bacterial growth in seven strains of the Acinetobacter species after 30 min treatment with tobramycin at suprainhibitory concentrations (postantibiotic effect - PAE) and at supra-subinhibitory concentrations (postantibiotic effect of subinhibitory concentrations - PA SME) as well as changes in surface hydrophobicity and in the production of lipase and histamine in the exposed strains were studied. Pharmacodynamic parameters (PAE and PA SME) as well as changes in bacterial characteristics tested were dependent on antibiotic concentration and on the strain used. Suppression of bacterial growth after treatment with tobramycin at 2x MIC was in a range of 0.6-4.5 h, a higher concentration (4x MIC) induced a longer PAE (1.9-5.4 h). Tobramycin at supra-subinhibitory concentratinos (2x MIC + 0.2x MIC and 4x MIC + 0.2x MIC) caused total suppression of bacterial growth. In the majority of the tobramycin-treated strains, an increase in hydrophobicity manifested by adherence of bacteria to xylene as well as an increase in hpolytic activity was observed. Tobramycin at the concentrations tested did not affect the production of histamine.
Reef-building corals are endangered animals with a complex colonial organization. Physiological mechanisms connecting multiple polyps and integrating them into a coral colony are still enigmatic. Using live imaging, particle tracking, and mathematical modeling, we reveal how corals connect individual polyps and form integrated polyp groups via species-specific, complex, and stable networks of currents at their surface. These currents involve surface mucus of different concentrations, which regulate joint feeding of the colony. Inside the coral, within the gastrovascular system, we expose the complexity of bidirectional branching streams that connect individual polyps. This system of canals extends the surface area by 4-fold and might improve communication, nutrient supply, and symbiont transfer. Thus, individual polyps integrate via complex liquid dynamics on the surface and inside the colony.
- MeSH
- druhová specificita MeSH
- korálnatci * fyziologie MeSH
- korálové útesy MeSH
- životní prostředí MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Sublethal concentrations (sub-MICs) of certain disinfectants are no longer effective in removing biofilms from abiotic surfaces and can even promote the formation of biofilms. Bacterial cells can probably adapt to these low concentrations of disinfectants and defend themselves by way of biofilm formation. In this paper, we report on three Staphylococcus aureus biofilm formers (strong B+++, moderate B++, and weak B+) that were cultivated with sub-MICs of commonly used disinfectants, ethanol or chloramine T, and quantified using Syto9 green fluorogenic nucleic acid stain. We demonstrate that 1.25-2.5% ethanol and 2500 μg/mL chloramine T significantly enhanced S. aureus biofilm formation. To visualize differences in biofilm compactness between S. aureus biofilms in control medium, 1.25% ethanol, or 2500 μg/mL chloramine T, scanning electron microscopy was used. To describe changes in abundance of surface-exposed proteins in ethanol- or chloramine T-treated biofilms, surface proteins were prepared using a novel trypsin shaving approach and quantified after dimethyl labeling by LC-LTQ/Orbitrap MS. Our data show that some proteins with adhesive functions and others with cell maintenance functions and virulence factor EsxA were significantly upregulated by both treatments. In contrast, immunoglobulin-binding protein A was significantly downregulated for both disinfectants. Significant differences were observed in the effect of the two disinfectants on the expression of surface proteins including some adhesins, foldase protein PrsA, and two virulence factors.
- MeSH
- bakteriální proteiny metabolismus MeSH
- biofilmy účinky léků růst a vývoj MeSH
- dezinficiencia aplikace a dávkování MeSH
- druhová specificita MeSH
- membránové proteiny metabolismus MeSH
- potravinářská mikrobiologie * MeSH
- regulace genové exprese u bakterií účinky léků fyziologie MeSH
- Staphylococcus aureus klasifikace účinky léků metabolismus MeSH
- viabilita buněk účinky léků MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- Publikační typ
- časopisecké články MeSH
The key process for immune response development is the recognition of bacteria by the immune system of the host based on the sensing of pathogen-associated molecular patterns (PAMP). One of the most important PAMP is the lipopolysaccharide (LPS) molecule, a complex molecule present in the outer membrane of Gram negative bacteria. In this study we were interested in how different parts of the LPS of Salmonella enterica serovar Enteritidis are recognized by porcine neutrophils. To this aim, we constructed S. Enteritidis mutants with rfaL and rfaC genes disabled in the attachment of the O-antigen and in the synthesis of the inner oligosaccharide core of LPS, respectively. We found that in the absence of serum, both the rfa mutants associated with neutrophils and stimulated them for reactive oxygen species (ROS) production significantly more than the wild-type strain. Addition of polymyxin B, which neutralized lipid A, the endotoxic moiety of LPS, effectively decreased the association of the wild-type strain and the rfaC mutant with neutrophils, but not the rfaL mutant. This indicates that the oligosaccharide core newly exposed on the surface in the rfaL mutant, protected from interaction in the wild-type strain by the O-antigen but completely absent in the rfaC mutant, may represent a new ligand for porcine neutrophils that cannot be neutralized by polymyxin B.
- MeSH
- lipopolysacharidy chemie MeSH
- mutace MeSH
- neutrofily imunologie mikrobiologie MeSH
- O-antigeny chemie genetika MeSH
- polymyxin B farmakologie MeSH
- prasata MeSH
- reaktivní formy kyslíku metabolismus MeSH
- Salmonella enteritidis chemie genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Naphthoquinones represent the group of plant secondary metabolites with cytotoxic properties based on their ability to generate reactive oxygen species and interfere with the processes of cell respiration. Due to this fact, the possible cytotoxic mechanisms on cellular and subcellular levels are investigated intensively. There are many targets of cytotoxic action on the cellular level; however, DNA is a critical target of many cytotoxic compounds. Due to the cytotoxic properties of naphthoquinones, it is necessary to study the processes of naphthoquinones, DNA interactions (1,4-naphthoquinone, binapthoquinone, juglone, lawsone, plumbagin), especially by using modern analytical techniques. In our work, the Raman spectroscopy was used to determine the possible binding sites of the naphthoquinones on the DNA and to characterize the bond of naphthoquinone to DNA. Experimental data reveals the relationships between the perturbations of structure-sensitive Raman bands and the types of the naphthoquinones involved. The modification of DNA by the studied naphthoquinones leads to the nonspecific interaction, which causes the transition of B-DNA into A-DNA conformation. The change of the B-conformation of DNA for all measured DNA modified by naphthoquinones except plumbagin is obvious.
- MeSH
- B-DNA chemie metabolismus MeSH
- DNA chemie metabolismus MeSH
- naftochinony chemie metabolismus MeSH
- Ramanova spektroskopie MeSH
- reaktivní formy kyslíku metabolismus MeSH
- rostliny chemie metabolismus MeSH
- sekundární metabolismus * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Tapeworms of the order Spathebothriidea Wardle et McLeod, 1952 (Cestoda) are reviewed. Molecular data made it possible to assess, for the first time, the phylogenetic relationships of all genera and to confirm the validity of Bothrimonus Duvernoy, 1842, Diplocotyle Krabbe, 1874 and Didymobothrium Nybelin, 1922. A survey of all species considered to be valid is provided together with new data on egg and scolex morphology and surface ultrastructure (i.e. microtriches). The peculiar morphology of the members of this group, which is today represented by five effectively monotypic genera whose host associations and geographical distribution show little commonality, indicate that it is a relictual group that was once diverse and widespread. The order potentially represents the earliest branch of true tapeworms (i.e. Eucestoda) among extant forms.
- MeSH
- Cestoda genetika fyziologie ultrastruktura MeSH
- druhová specificita MeSH
- fylogeneze MeSH
- ovum klasifikace ultrastruktura MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
A new acanthocepohalan species, Moniliformis saudi sp. n. is described from the desert hedgehog, Paraechinus aethiopicus (Ehrenberg), in central Saudi Arabia. Fourteen other valid species of Moniliformis Travassos, 1915 are recognised. The new species of Moniliformis is distinguished by having a small proboscis (315-520 µm long and 130-208 µm wide) with two apical pores, 14 rows of 8 hooks each and small hooks, thre largest being 25-31 µm long anteriorly. Distinguishing features are incorporated in a dichotomous key to the species of Moniliformis. The description is augmented by scanning electron microscopical (SEM) observation and DNA analysis of nuclear (18S rRNA) and mitochondrial (cytochrome oxidase subunit 1; cox1) gene sequences. Attached worms cause extensive damage to the immediate area of attachment in the host intestine. This includes tissue necrosis and blood loss due to damage to capillary beds. Worms also obstruct essential absorbing surfaces.
- MeSH
- DNA helmintů genetika MeSH
- druhová specificita MeSH
- helmintóza parazitologie patologie MeSH
- ježkovití parazitologie MeSH
- Moniliformis anatomie a histologie klasifikace genetika ultrastruktura MeSH
- střeva parazitologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Saudská Arábie MeSH
The influence of the matrix solution, sample form and deposition technique on the quality MALDI-TOF mass spectra was examined and assessed with the aim to improve MALDI-TOF MS performance for the identification of microorganisms and to enable automatic spectra acquisition. It was observed that the use of matrix compounds ferulic and sinapinic acid may result in improved mass spectral features, in terms of signal resolution and S/N ratio, as compared to alpha-cyano-4-hydroxycinnamic acid, which was, on the other hand, found to be the only matrix compound that enabled fully automatic mass spectra acquisition. The robustness of the whole sample preparation procedure was then assessed on a set of 25 strains of four Acinetobacter species. Results showed reproducible detection of subtle mass spectral differences between strains belonging to the same species, although they do not confirm the possibility of reliable strain typing.
Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) represents a simple reliable approach for rapid bacterial identification based on specific peptide/protein fingerprints. However, cell-wall characteristics of mycobacterial species, and their well known stability, complicate MALDI-TOF MS profiling analysis. In this study, we tested two recently published protocols for inactivation and disruption of mycobacteria, and we also examined the influence of different culture conditions (four culture media and five cultivation times) on mass spectral quality and the discriminatory power of the method. We found a significant influence of sample pretreatment method and culture medium on species identification and differentiation for a total of 10 strains belonging to Mycobacterium phlei and Mycobacterium smegmatis. Optimum culture conditions yielding the highest identification success rate against the BioTyper database (Bruker Daltonics) and permitting the possibility of automatic acquisition of mass spectra were found to be distinct for the two mycobacterial species examined. Similarly, individual changes in growth conditions had diverse effects on the two species. For these reasons, thorough control over cultivation conditions should always be employed to maximize the performance and discriminatory power of MALDI-TOF MS profiling, and cultivation conditions must be optimized separately for individual groups of mycobacterial species/strains.
