AIM: Clostridium species, such as Clostridium perfringens, C. baratii, C. colicanis, Paraclostridium bifermentans, and Paeniclostridium sordellii, are Gram-positive, anaerobic, endospore-forming bacteria with diverse pathogenic mechanisms. While these species are commensals in the guts of variable animal species, such as anteaters, they are less frequently found in humans. The diet of anteaters, which includes chitin and formic acid, plays an important role in their specific dietary habits, as well as in clostridial metabolism. METHODS AND RESULTS: This study investigates the metabolic diversity and responses of anteater clostridial isolates to various substrates, namely chitin, chitosan, cellulose, N-acetyl-D-glucosamine (NAG), and glucose. All tested clostridia were able to grow in the presence of chitin, cellulose, NAG, and glucose, but varied in metabolite production. However, the presence of chitosan surprisingly showed an antimicrobial effect against clostridia, especially Pae. sordellii, P. bifermentans, and C. colicanis. The results demonstrate significant variations in fermentation profiles, and metabolite production across substrates and clostridial species. Acetate production was detected as common for all tested clostridia despite species variability and incoming substrates, as well as lactate, butyrate, propionate, and formate for some strains. CONCLUSION: In relation to digestion, anteater clostridia could play an important role in chitin and its degradation products, which, in the end, can influence clostridial occurrence and pathogenicity via chitosan.
- Klíčová slova
- N-acetyl-D-glucosamine, antimicrobial activity, cellulose, chitin, chitosan, clostridia, fermentation, metabolites,
- Publikační typ
- časopisecké články MeSH
BACKGROUND: Only a few studies dealt with the occurrence of endospore-forming clostridia in the microbiota of infants without obvious health complications. METHODS: A methodology pipeline was developed to determine the occurrence of endospore formers in infant feces. Twenty-four fecal samples (FS) were collected from one infant in monthly intervals and were subjected to variable chemical and heat treatment in combination with culture-dependent analysis. Isolates were identified by MALDI-TOF mass spectrometry, 16S rRNA gene sequencing, and characterized with biochemical assays. RESULTS: More than 800 isolates were obtained, and a total of 21 Eubacteriales taxa belonging to the Clostridiaceae, Lachnospiraceae, Oscillospiraceae, and Peptostreptococcaceae families were detected. Clostridium perfringens, C. paraputrificum, C. tertium, C. symbiosum, C. butyricum, and C. ramosum were the most frequently identified species compared to the rarely detected Enterocloster bolteae, C. baratii, and C. jeddahense. Furthermore, the methodology enabled the subsequent cultivation of less frequently detectable gut taxa such as Flavonifractor plautii, Intestinibacter bartlettii, Eisenbergiella tayi, and Eubacterium tenue. The isolates showed phenotypic variability regarding enzymatic activity, fermentation profiles, and butyrate production. CONCLUSIONS: Taken together, this approach suggests and challenges a cultivation-based pipeline that allows the investigation of the population of endospore formers in complex ecosystems such as the human gastrointestinal tract.
- Klíčová slova
- Butyrate, Clostridium, Cultivation, Endospore formers, Fermentation profiles, Infant gut microbiota,
- MeSH
- Clostridium * genetika MeSH
- feces mikrobiologie MeSH
- Firmicutes genetika MeSH
- kojenec MeSH
- lidé MeSH
- mikrobiota * MeSH
- RNA ribozomální 16S genetika MeSH
- Check Tag
- kojenec MeSH
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- RNA ribozomální 16S MeSH
Substrate geochemistry is an important factor influencing early microbial development after glacial retreat on nutrient-poor geological substrates in the High Arctic. It is often difficult to separate substrate influence from climate because study locations are distant. Our study in the retreating Nordenskiöldbreen (Svalbard) is one of the few to investigate biogeochemical and microbial succession in two adjacent forefields, which share the same climatic conditions but differ in their underlying geology. The northern silicate forefield evolved in a classical chronosequence, where most geochemical and microbial parameters increased gradually with time. In contrast, the southern carbonate forefield exhibited high levels of nutrients and microbial biomass at the youngest sites, followed by a significant decline and then a gradual increase, which caused a rearrangement in the species and functional composition of the bacterial and fungal communities. This shuffling in the early stages of succession suggests that high nutrient availability in the bedrock could have accelerated early soil succession after deglaciation and thereby promoted more rapid stabilization of the soil and production of higher quality organic matter. Most chemical parameters and bacterial taxa converged with time, while fungi showed no clear pattern.
- Klíčová slova
- Arctic soils, biogeochemistry, deglaciation, glacier forefield, microbial assembly, soil succession,
- MeSH
- Bacteria genetika MeSH
- ledový příkrov * mikrobiologie MeSH
- minerály MeSH
- půda * chemie MeSH
- půdní mikrobiologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Svalbard MeSH
- Názvy látek
- minerály MeSH
- půda * MeSH
The accuracy of environmental risk assessment depends upon selecting appropriate matrices to extract the most risk-relevant portion of contaminant(s) from the soil. Here, we applied the chelatants EDTA and tartaric acid to extract a metal-contaminated soil. Pistia stratiotes was applied as an indicator plant to measure accumulation from the metal-laden bulk solutions generated, in a hydroponic experiment lasting 15 days. Speciation modeling was used to elucidate key geo-chemical mechanisms impacting matrix and metal-specific uptake revealed by experimental work. The highest concentrations of soil-borne metals were extracted from soil by EDTA (7.4% for Cd), but their uptake and translocation to the plant were restricted due to the formation of stable metal complexes predominantly with DOC. Tartaric acid solubilized metals to a lesser extent (4.6% for Cd), but a higher proportion was plant available due to its presence mainly in the form of bivalent metal cations. The water extraction showed the lowest metal extraction (e.g., 3.9% for Cd), but the metal species behaved similarly to those extracted by tartaric acid. This study demonstrates that not all extractions are equal and that metal-specific speciation will impact accurate risk assessment in soil (water)-plant systems. In the case of EDTA, a deleterious impact on DOC leaching is an obvious drawback. As such, further work should now determine soil and not only metal-specific impacts of chelatants on the extraction of environmentally relevant portions of metal(loid)s.
- Klíčová slova
- DOC leaching, Metal speciation modeling, Rhizofiltration, Soil chelatants, Water lettuce,
- MeSH
- Araceae * MeSH
- biodegradace MeSH
- EDTA chemie MeSH
- kadmium MeSH
- látky znečišťující půdu * analýza MeSH
- půda chemie MeSH
- těžké kovy * analýza MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- EDTA MeSH
- kadmium MeSH
- látky znečišťující půdu * MeSH
- půda MeSH
- tartaric acid MeSH Prohlížeč
- těžké kovy * MeSH
The current study assesses and predicts cadmium (Cd) concentration in agricultural soil using two Cd datasets, namely legacy data (LD) and preferential sampling-legacy data (PS-LD), along with four streams of auxiliary datasets extracted from Sentinel-2 (S2) and Landsat-8 (L8) bands. The study was divided into two contexts: Cd prediction in agricultural soil using LD, ensemble models, 10 and 20 m spatial resolution of S2 and L8 (context 1), and Cd prediction in agricultural soil using PS-LD, ensemble models and 10 and 20 m spatial resolution of S2 and L8 (context 2). In context 1, ensemble 1, L8 with PS-LD was the cumulative optimal approach that predicted Cd in agricultural soil with a higher R2 value of 0.76, root mean square error (RMSE) of 0.66, mean absolute error (MAE) of 0.35, and median absolute error (MdAE) of 0.13. However, with R2 = 0.78, RMSE = 0.63, MAE = 0.34, and MdAE = 0.15, ensemble 1, S2 of PS-LD was the best prediction approach in predicting Cd concentration in agricultural soil in context 2. Overall, the predictions from both contexts indicated that ensemble 1 of S2 combined with PS-LD was the most appropriate and best model for Cd prediction in agricultural soil. The modeling approaches' uncertainty in both contexts was assessed using ensemble-sequential gaussian simulation (EnSGS), which revealed that the degree of uncertainty propagated in the study area was within 5% in both contexts. The combination of the PS dataset and the LD along with ensemble models and the remote sensing dataset, produced promising results. Nonetheless, the results demonstrated that the 20 m spatial resolution band dataset used in the prediction of Cd in agricultural soil outperformed the 10 m spatial resolution. When PS is combined with LD, an appropriate modeling approach, and a well-correlated remote sensing dataset are used, good results are obtained.
- Klíčová slova
- Ensemble models, Legacy data, Preferential sampling, Remote sensing, Uncertainty assessment,
- MeSH
- kadmium MeSH
- látky znečišťující půdu * analýza MeSH
- monitorování životního prostředí metody MeSH
- půda * MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
- Názvy látek
- kadmium MeSH
- látky znečišťující půdu * MeSH
- půda * MeSH
The methodology described here presents the procedures for determining physical soil properties of undisturbed soil samples. Besides describing the methods for determining bulk and particle density, moisture content and porosity of the soil in detail, it also offers a way of determining soil's water holding properties when there is no pressure membrane apparatus available. This method is based on a capillary water saturation experiment and gravimetric measurements performed in different time intervals after the saturation (30 minutes, 2 hours, and 24 hours). With a few, simple to follow steps, and not using complicated and space-consuming equipment, it can be replicated in almost any laboratory, and the results are easily interpreted. The method was, and still is, widely used in the Czech Republic, and some parts of it are used as standard soil testing methods. To a lesser or greater detail, this method is described in Rejšek (1999), Valla et al. (2011), Pospíšilová et al. (2016) and ÚKZÚZ (2016), and this methodology is compiled from those publications, mainly focusing (and using the same abbreviations) on the procedures described by Valla et al. (2011). The methodology described does not essentially differ from the original, but the steps here have been described to a greater detail, based on the practical experiences obtained over the years, in order to make some common mistakes less likely to happen. The methodology is further complemented with graphical illustrations for each step described in the process, making it clearer, more easily understood, and easier to replicate. Since this methodology has not been available in English so far, this guide offers a great opportunity of its replication on an international level.•Simple, cost-effective and environmentally friendly method for determining physical soil properties•Easy replication and results interpretation•Results can be obtained even in non-highly specialized soil laboratories.
Mining and smelting activities can contaminate soils and affect farming due to high emissions and input of potentially toxic elements (PTE) into the environment. Soils (sampled from two depths) and market vegetables from vegetable gardens located within the vicinity of unconfined slag deposits from decades of mining and smelting activities in Kutná Hora, Czechia were assessed to determine to what extent they pose a health hazard to communities that use these gardens. Pseudo-total As concentrations in the soils exceeded background levels (4.5 mg kg-1) 1.9-93 times, with higher concentrations in the deeper layer. The pseudo-total concentrations of PTE in soils ranked in the order As > Zn > Cd > Pb. Phyto-available concentrations of PTE in soils were relatively low, compared to pseudo-total concentrations. Concentration of As, Cd, Pb and Zn in the vegetables exceeded guideline values, with the highest concentrations found in the fruits of cucumber, peppers, and zucchini. Despite low phyto-available PTE concentrations in soils, all the PTE concentrations in the vegetables surpassed the guidelines set by the Czech Ministry of Health and EU directive, indicating a health hazard to consumers.
- MeSH
- hodnocení rizik MeSH
- kadmium MeSH
- látky znečišťující půdu * analýza MeSH
- monitorování životního prostředí MeSH
- olovo MeSH
- půda MeSH
- těžké kovy * analýza MeSH
- zahrady MeSH
- zelenina MeSH
- zinek analýza MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Čína MeSH
- Názvy látek
- kadmium MeSH
- látky znečišťující půdu * MeSH
- olovo MeSH
- půda MeSH
- těžké kovy * MeSH
- zinek MeSH
Strains of Limosilactobacillus reuteri are used as starter and bioprotective cultures and contribute to the preservation of food through the production of fermentation metabolites lactic and acetic acid, and of the antimicrobial reuterin. Reuterin consists of acrolein and 3-hydroxypropionaldehyde (3-HPA), which can be further metabolized to 1,3-propanediol and 3-hydroxypropionic acid (3-HP). While reuterin has been the focus of many investigations, the contribution of 3-HP to the antimicrobial activity of food related reuterin-producers is unknown. We show that the antibacterial activity of 3-HP was stronger at pH 4.8 compared to pH 5.5 and 6.6. Gram-positive bacteria were in general more resistant against 3-HP and propionic acid than Gram-negative indicator strains including common food pathogens, while spoilage yeast and molds were not inhibited by ≤ 640 mM 3-HP. The presence of acrolein decreased the minimal inhibitory activity of 3-HP against E. coli indicating synergistic antibacterial activity. 3-HP was formed during the growth of the reuterin-producers, and by resting cells of L. reuteri DSM 20016. Taken together, this study shows that food-related reuterin producers strains synthesize a second antibacterial compound, which might be of relevance when strains are added as starter or bioprotective cultures to food products.
- Klíčová slova
- 3-Hydroxypropionic acid, Antibacterial, Antifungal, Limosilactobacillus reuteri, Reuterin,
- MeSH
- antiinfekční látky chemie metabolismus farmakologie MeSH
- Bacteria účinky léků růst a vývoj MeSH
- fermentace MeSH
- glyceraldehyd analogy a deriváty chemie metabolismus MeSH
- glycerol metabolismus MeSH
- koncentrace vodíkových iontů MeSH
- kyselina mléčná analogy a deriváty chemie metabolismus farmakologie MeSH
- kyselina octová metabolismus MeSH
- Lactobacillaceae chemie růst a vývoj metabolismus MeSH
- potravinářská mikrobiologie MeSH
- propan chemie metabolismus MeSH
- stabilita léku MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- 3-hydroxypropionaldehyde MeSH Prohlížeč
- antiinfekční látky MeSH
- glyceraldehyd MeSH
- glycerol MeSH
- hydracrylic acid MeSH Prohlížeč
- kyselina mléčná MeSH
- kyselina octová MeSH
- propan MeSH
We studied the key geochemical and mineralogical factors that could affect the fractionation of stable thallium (Tl) isotopes in soil. A set of grassland soil samples enriched in geogenic Tl in combination with selected Tl-containing mineral materials from the Czech Republic (Kluky) were investigated for this purpose. The results demonstrate significant incorporation of Tl in pedogenic (specific) Mn-oxide, which led to a large accumulation of the heavy 205Tl isotope (∼+14 ε205Tl units), presumably resulting from oxidative Tl sorption. Consequently, we concluded that the Mn-oxide-controlled Tl uptake is the primary cause of the observed 205Tl enrichment in the middle profile zone, at the A/B soil horizon interface, with up to +4 of ε205Tl. Furthermore, our results displayed a clear relationship between the Tl isotopic fractionation degree and the Mn-oxide soil concentration (R2 = 0.6), as derived from the oxalate-extractable data. A combination of soil and mineralogical considerations suggests that 205Tl enrichment in respective soil samples is also partly due to the Tl present in micaceous clay minerals, mainly illite, which is the predominant pedogenic Tl host phase. In line with our previous results, this Tl behavior can be inferred from systematic Mn-oxide degradation and the associated Tl (enriched in 205Tl) cycling in the studied soils and thus, presumably in the redoximorphic soils in general.
- Klíčová slova
- Fractionation, Illite, Isotope, Mn-oxide, Thallium,
- MeSH
- izotopy MeSH
- látky znečišťující půdu analýza MeSH
- půda * MeSH
- thallium analýza MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
- Názvy látek
- izotopy MeSH
- látky znečišťující půdu MeSH
- půda * MeSH
- thallium MeSH
