Overcoming the skin barrier properties efficiently, temporarily, and safely for successful transdermal drug delivery remains a challenge. We synthesized three series of potential skin permeation enhancers derived from natural amino acid derivatives proline, 4-hydroxyproline, and pyrrolidone carboxylic acid, which is a component of natural moisturizing factor. Permeation studies using in vitro human skin identified dodecyl prolinates with N-acetyl, propionyl, and butyryl chains (Pro2, Pro3, and Pro4, respectively) as potent enhancers for model drugs theophylline and diclofenac. The proline derivatives were generally more active than 4-hydroxyprolines and pyrrolidone carboxylic acid derivatives. Pro2-4 had acceptable in vitro toxicities on 3T3 fibroblast and HaCaT cell lines with IC50 values in tens of μM. Infrared spectroscopy using the human stratum corneum revealed that these enhancers preferentially interacted with the skin barrier lipids and decreased the overall chain order without causing lipid extraction, while their effects on the stratum corneum protein structures were negligible. The impacts of Pro3 and Pro4 on an in vitro transepidermal water loss and skin electrical impedance were fully reversible. Thus, proline derivatives Pro3 and Pro4 have an advantageous combination of high enhancing potency, low cellular toxicity, and reversible action, which is important for their potential in vivo use as the skin barrier would quickly recover after the drug/enhancer administration is terminated.
- MeSH
- aplikace kožní MeSH
- hydroxyprolin metabolismus MeSH
- kožní absorpce * MeSH
- kůže metabolismus MeSH
- kyseliny karboxylové metabolismus MeSH
- léčivé přípravky metabolismus MeSH
- lidé MeSH
- organické látky metabolismus MeSH
- permeabilita MeSH
- prolin * metabolismus MeSH
- pyrrolidinony farmakologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Due to the ability of soil bacteria to solubilize minerals, fix N2 and mobilize nutrients entrapped in the organic matter, their role in nutrient turnover and plant fitness is of high relevance in forest ecosystems. Although several authors have already studied the organic matter decomposing enzymes produced by soil and plant root-interacting bacteria, most of the works did not account for the activity of cell wall-attached enzymes. Therefore, the enzyme deployment strategy of three bacterial collections (genera Luteibacter, Pseudomonas and Arthrobacter) associated with Quercus spp. roots was investigated by exploring both cell-bound and freely-released hydrolytic enzymes. We also studied the potential of these bacterial collections to produce enzymes involved in the transformation of plant and fungal biomass. Remarkably, the cell-associated enzymes accounted for the vast majority of the total activity detected among Luteibacter strains, suggesting that they could have developed a strategy to maintain the decomposition products in their vicinity, and therefore to reduce the diffusional losses of the products. The spectrum of the enzymes synthesized and the titres of activity were diverse among the three bacterial genera. While cellulolytic and hemicellulolytic enzymes were rather common among Luteibacter and Pseudomonas strains and less detected in Arthrobacter collection, the activity of lipase was widespread among all the tested strains. Our results indicate that a large fraction of the extracellular enzymatic activity is due to cell wall-attached enzymes for some bacteria, and that Quercus spp. root bacteria could contribute at different levels to carbon (C), phosphorus (P) and nitrogen (N) cycles.
Aerobic anoxygenic photosynthetic bacteria are an important component of marine microbial communities. They produce energy in light using bacteriochlorophyll a containing photosystems. This extra energy provides an advantage over purely heterotrophic bacteria. One of the most intensively studied AAP bacteria is Dinoroseobacter shibae, a member of the environmentally important Roseobacter clade. Light stimulates its growth and metabolism, but the effect of light intensity remains unclear. Here, we show that an increase in biomass along an irradiance gradient followed the exponential rise to the maximum curve, with saturation at about 300 µmol photons m-2 s-1 , without any inhibition at light intensities up to 600 µmol photons m-2 s-1 . The cells adapted to higher irradiance by reducing pigmentation and increasing the electron transfer rate. This additional energy allowed D. shibae to redirect the metabolism of organic carbon sources such as glucose, leucine, glutamate, acetate and pyruvate toward anabolism, resulting in a twofold increase of their assimilation rates. We provide equations that can be feasibly incorporated into the existing model of D. shibae metabolism to further advance our understanding of the role of photoheterotrophy in the ocean.
- MeSH
- bakteriochlorofyl A metabolismus MeSH
- biomasa MeSH
- energetický metabolismus fyziologie MeSH
- fotosyntéza fyziologie MeSH
- organické látky metabolismus MeSH
- Roseobacter metabolismus MeSH
- světlo MeSH
- transport elektronů fyziologie MeSH
- vodní organismy metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Arbuscular mycorrhizal (AM) fungi can significantly contribute to plant nitrogen (N) uptake from complex organic sources, most likely in concert with activity of soil saprotrophs and other microbes releasing and transforming the N bound in organic forms. Here, we tested whether AM fungus (Rhizophagus irregularis) extraradical hyphal networks showed any preferences towards certain forms of organic N (chitin of fungal or crustacean origin, DNA, clover biomass, or albumin) administered in spatially discrete patches, and how the presence of AM fungal hyphae affected other microbes. By direct 15N labeling, we also quantified the flux of N to the plants (Andropogon gerardii) through the AM fungal hyphae from fungal chitin and from clover biomass. The AM fungal hyphae colonized patches supplemented with organic N sources significantly more than those receiving only mineral nutrients, organic carbon in form of cellulose, or nothing. Mycorrhizal plants grew 6.4-fold larger and accumulated, on average, 20.3-fold more 15N originating from the labeled organic sources than their nonmycorrhizal counterparts. Whereas the abundance of microbes (bacteria, fungi, or Acanthamoeba sp.) in the different patches was primarily driven by patch quality, we noted a consistent suppression of the microbial abundances by the presence of AM fungal hyphae. This suppression was particularly strong for ammonia oxidizing bacteria. Our results indicate that AM fungi successfully competed with the other microbes for free ammonium ions and suggest an important role for the notoriously understudied soil protists to play in recycling organic N from soil to plants via AM fungal hyphae.
- MeSH
- Acanthamoeba metabolismus MeSH
- amoniak metabolismus MeSH
- Andropogon růst a vývoj metabolismus mikrobiologie MeSH
- Bacteria metabolismus MeSH
- dusík metabolismus MeSH
- hyfy metabolismus MeSH
- mykorhiza metabolismus MeSH
- organické látky metabolismus MeSH
- oxidace-redukce MeSH
- Publikační typ
- časopisecké články MeSH
Bark beetles (Curculionidae: Scolytinae) feed on the xylem and phloem of their host, which are composed of structural carbohydrates and organic compounds that are not easily degraded by the insects. Some of these compounds might be hydrolyzed by digestive enzymes produced by microbes present in the gut of these insects. In this study, we evaluated the enzymatic capacity of bacteria (Acinetobacter lwoffii, Arthrobacter sp., Pseudomonas putida, Pseudomonas azotoformans, and Rahnella sp.) and yeasts (Candida piceae, Candida oregonensis, Cyberlindnera americana, Zygoascus sp., and Rhodotorula mucilaginosa) isolated from the Dendroctonus rhizophagus gut to hydrolyze cellulose, xylan, pectin, starch, lipids, and esters. All isolates, with the exception of C. piceae, showed lipolytic activity. Furthermore, P. putida, P. azotoformans, C. americana, C. piceae, and R. mucilaginosa presented amylolytic activity. Esterase activity was shown by A. lwoffii, P. azotoformans, and Rahnella sp. Cellulolytic and xylanolytic activities were present only in Arthrobacter sp. and P. azotoformans. The pectinolytic activity was not recorded in any isolate. This is the first study to provide evidence on the capacity of microbes associated with the D. rhizophagus gut to hydrolyze specific substrates, which might cover part of the nutritional requirements for the development, fitness, and survival of these insects.
- MeSH
- Bacteria izolace a purifikace metabolismus MeSH
- biotransformace MeSH
- gastrointestinální trakt mikrobiologie MeSH
- kvasinky izolace a purifikace metabolismus MeSH
- nosatcovití mikrobiologie MeSH
- organické látky metabolismus MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Bioaccumulation factors (BAFs) of organic pollutants to soil biota, often required by risk assessment, are mostly obtained in non-sterile laboratory-contaminated artificial soils. However, microbial degradation has been indicated by many authors to influence the fate of hydrophobic organic compounds (HOCs) in soils. A question arises if the microbial community of peat which is used for artificial soil preparation affects the measured values of BAFs. In this study the effect of soil microorganisms on bioavailability of HOCs was studied and a portion of each soil was sterilized by gamma irradiation. Results indicated that the sterilization process significantly affected the fate of polycyclic aromatic hydrocarbons (PAHs; phenanthrene and pyrene) and increased bioavailability of these compounds to earthworms with BAFs several times higher in the sterile soils compared to their non-sterile variants. This suggests that sterilization of soils can be used as the "worst-case scenario" for laboratory tests of toxicity or bioaccumulation of biodegradable HOCs such as PAHs. It represents a situation of limited microbial degradation resulting in higher bioavailable fractions to other organisms (e.g. invertebrates). This may be the case in soils where microbial communities face stresses caused by contamination or land management. The bioavailability of chlorinated HOCs (lindane, 4,4'-DDT and PCB 153) was not affected by sterilization, as their BAFs were similar in the sterile and non-sterile soils during the experiment.
- MeSH
- biologická dostupnost * MeSH
- hydrofobní a hydrofilní interakce MeSH
- látky znečišťující půdu analýza metabolismus MeSH
- Oligochaeta metabolismus MeSH
- organické látky chemie metabolismus MeSH
- polycyklické aromatické uhlovodíky chemie metabolismus MeSH
- půda chemie MeSH
- půdní mikrobiologie MeSH
- sterilizace MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The accumulation of glycerol is essential for yeast viability upon hyperosmotic stress. Here we show that the osmotolerant yeast Zygosaccharomyces rouxii has two genes, ZrSTL1 and ZrSTL2, encoding transporters mediating the active uptake of glycerol in symport with protons, contributing to cell osmotolerance and intracellular pH homeostasis. The growth of mutants lacking one or both transporters is affected depending on the growth medium, carbon source, strain auxotrophies, osmotic conditions and the presence of external glycerol. These transporters are localised in the plasma membrane, they transport glycerol with similar kinetic parameters and besides their expected involvement in the cell survival of hyperosmotic stress, they surprisingly both contribute to an efficient survival of hypoosmotic shock and to the maintenance of intracellular pH homeostasis under non-stressed conditions. Unlike STL1 in Sa. cerevisiae, the two Z. rouxii STL genes are not repressed by glucose, but their expression and activity are downregulated by fructose and upregulated by non-fermentable carbon sources, with ZrSTL1 being more influenced than ZrSTL2. In summary, both transporters are highly important, though Z. rouxii CBS 732(T) cells do not use external glycerol as a source of carbon.
- MeSH
- biologický transport MeSH
- delece genu MeSH
- fyziologický stres MeSH
- glycerol metabolismus MeSH
- koncentrace vodíkových iontů MeSH
- kultivační média chemie MeSH
- mikrobiální viabilita MeSH
- organické látky metabolismus MeSH
- osmoregulace * MeSH
- osmotický tlak MeSH
- regulace genové exprese u hub účinky léků MeSH
- symportéry genetika metabolismus MeSH
- Zygosaccharomyces genetika růst a vývoj metabolismus fyziologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The presented study investigates the use of passive sampling, i.e. solid phase microextraction with polydimethylsiloxane fibers (PDMS-SPME), to assess the bioavailability of fiver neutral organic chemicals (phenanthrene, pyrene, lindane, p,p'-DDT, and PCB 153) spiked to natural and artificial soils after different aging times. Contaminant bioavailability was assessed by comparing PDMS concentrations with results from a 10 day bioaccumulation test with earthworms (Eisenia fetida). The hypotheses tested were (i) organic carbon (OC) normalization, which is commonly used to account for sorption and bioavailability of hydrophobic organic chemicals in soil risk assessment, has limitations due to differences in sorptive properties of OC and aging processes (i.e. sequestration and biodegradation) and (ii) PDMS-SPME provides a more reliable measure of soil contaminant bioavailability than OC normalized soil concentrations. The above stated hypotheses were confirmed since the results showed that: (i) the PDMS/soil organic carbon partition ratio (R) accounting for the role that OC plays in partitioning significantly differed between soils and aging times and (ii) the correlation with earthworm concentrations was better using porewater concentrations derived from PDMS concentrations than when organic normalized soil concentrations were used. Capsule: Sorption of organic compounds measured by SPME method and their bioavailability to earthworms cannot be reliably predicted using OC content.
- MeSH
- látky znečišťující půdu chemie metabolismus MeSH
- mikroextrakce na pevné fázi * MeSH
- monitorování životního prostředí MeSH
- Oligochaeta chemie metabolismus MeSH
- organické látky analýza metabolismus MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Hydrophobic organic contaminants in soils may pose toxicity or transfer to food chains after their uptake to soil biota. However, uptake data for earthworms are usually limited, as: (a) only fixed exposure times are studied instead of whole uptake kinetics and (b) studies including compounds with different environmental properties and more than two soils of different properties are quite rare. In our study, five persistent organic pollutants (phenanthrene, pyrene, lindane, p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT), and polychlorinated biphenyl congener No. 153 (PCB 153)) were added to six soils of a wide range of soil properties. Detailed kinetics of uptake to earthworms Eisenia fetida were measured. Results indicated that an equilibrium of concentrations for p,p'-DDT and PCB 153 was reached after 11 days of exposure in all soils. Uptake of phenanthrene, pyrene, and lindane was strongly influenced by the decrease in concentrations in the soils, resulting in peak-shaped accumulation curves. Only in soils with the highest total organic carbon content (7.9 and 20.2%), the equilibrium of lindane concentrations was achieved (after 17 and 5 days of exposure, respectively). We recommend calculating bioaccumulation factors as a ratio of the uptake and elimination rate constants to precise the risk assessment.
- MeSH
- DDT chemie metabolismus MeSH
- hexachlorcyklohexan chemie metabolismus MeSH
- insekticidy chemie metabolismus MeSH
- kinetika MeSH
- látky znečišťující půdu chemie metabolismus MeSH
- látky znečišťující životní prostředí chemie metabolismus MeSH
- Oligochaeta metabolismus MeSH
- organické látky chemie metabolismus MeSH
- polychlorované bifenyly chemie metabolismus MeSH
- polycyklické sloučeniny analýza MeSH
- půda chemie MeSH
- statistické modely MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Bacterial populations display high heterogeneity in viability and physiological activity at the single-cell level, especially under stressful conditions. We demonstrate a novel staining protocol for multiparameter assessment of individual cells in physiologically heterogeneous populations of cyanobacteria. The protocol employs fluorescent probes, i.e., redox dye 5-cyano-2,3-ditolyl tetrazolium chloride, 'dead cell' nucleic acid stain SYTOX Green, and DNA-specific fluorochrome 4',6-diamidino-2-phenylindole, combined with microscopy image analysis. Our method allows simultaneous estimates of cellular respiration activity, membrane and nucleoid integrity, and allows the detection of photosynthetic pigments fluorescence along with morphological observations. The staining protocol has been adjusted for, both, laboratory and natural populations of the genus Phormidium (Oscillatoriales), and tested on 4 field-collected samples and 12 laboratory strains of cyanobacteria. Based on the mentioned cellular functions we suggest classification of cells in cyanobacterial populations into four categories: (i) active and intact; (ii) injured but active; (iii) metabolically inactive but intact; (iv) inactive and injured, or dead.
- MeSH
- barvení a značení metody MeSH
- časové faktory MeSH
- fluorescenční barviva metabolismus MeSH
- fluorescenční spektrometrie MeSH
- indoly metabolismus MeSH
- organické látky metabolismus MeSH
- sinice cytologie metabolismus MeSH
- tetrazoliové soli metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
