As humanity embarks on interplanetary exploration and envisions future colonies beyond Earth, understanding the impact of extreme environments on life becomes paramount. Among these factors, the hypomagnetic field (HMF)-a condition where the protective geomagnetic field is absent-remains poorly understood, especially regarding its effects on (micro)organisms. To our knowledge, this is the first study to examine how short-term exposure to an HMF (24 h to 7 days) affects the growth of three different microorganisms, Saccharomyces cerevisiae, Acidithiobacillus ferrooxidans, and Lactobacillus plantarum, using a specialized hypomagnetic chamber and advanced spectrophotometric analysis. We demonstrate significant growth inhibition in S. cerevisiae (23%) and A. ferrooxidans (68%), with L. plantarum remaining unaffected. This inhibitory effect appears reversible, diminishing as organisms return to normal geomagnetic conditions. These findings reveal that the HMF acts as a temporary environmental stressor, underscoring the need for deeper exploration of its biological effects. Our work sets the stage for further research into how the space environment may shape microbial ecosystems critical to future human endeavors in space.

• Klíčová slova
• bacteria, environmental stress, growth inhibition, hypomagnetic field, microorganisms, yeast,
• Publikační typ
• časopisecké články MeSH

Agriculture, food industry, and manufacturing are just some of the areas where anaerobic technology can be used. Currently, anaerobic technologies are mainly used for wastewater treatment, solid waste treatment, or for the production of electrical and thermal energy from energy crops processing. However, a clear trend is towards more intensive use of this technology in biomass and biodegradable waste processing and hydrogen or biomethane production. An enormous number of anaerobic digesters are operating worldwide but there is very little information about the effect of different substrate combinations on the methanogens community. This is due to the fact that each of the anaerobic digesters has its own unique microbial community. For the most effective management of anaerobic processes it would be important to know the composition of a consortium of anaerobic microorganisms present in anaerobic digesters processing different input combinations of raw material. This paper characterizes the effect of the input raw materials on the diversity of the methanogen community. Two predominant microorganisms in anaerobic digesters were found to be 99% identity by the sequences of the 16S rRNA gene to the Methanoculleus and Thermogymnomonas genera deposited in GenBank.

• Klíčová slova
• Archaea, anaerobic digesters, biogas, methane production, methanogenic microorganisms,
• Publikační typ
• časopisecké články MeSH

Microbial biomass is a key parameter needed for the quantification of microbial turnover rates and their contribution to the biogeochemical element cycles. However, estimates of microbial biomass rely on empirically derived mass-to-volume relationships, and large discrepancies exist between the available empirical conversion factors. Here we report a significant nonlinear relationship between carbon mass and cell volume ([Formula: see text]; [Formula: see text]) based on direct cell mass, volume, and elemental composition measurements of 12 prokaryotic species with average volumes between 0.011 and 0.705 μm3 The carbon mass density of our measured cells ranged from 250 to 1,800 fg of C μm-3 for the measured cell volumes. Compared to other currently used models, our relationship yielded up to 300% higher carbon mass values. A compilation of our and previously published data showed that cells with larger volumes (>0.5 μm3) display a constant (carbon) mass-to-volume ratio, whereas cells with volumes below 0.5 μm3 exhibit a nonlinear increase in (carbon) mass density with decreasing volume. Small microorganisms dominate marine and freshwater bacterioplankton as well as soils and marine and terrestrial subsurface. The application of our experimentally determined conversion factors will help to quantify the true contribution of these microorganisms to ecosystem functions and global microbial biomass.IMPORTANCE Microorganisms are a major component of Earth's biosphere, and their activity significantly affects the biogeochemical cycling of bioavailable elements. To correctly determine the flux of carbon and energy in the environment, reliable estimates of microbial abundances and cellular carbon content are necessary. However, accurate assessments of cellular carbon content and dry weight are not trivial to obtain. Here we report direct measurements of cell dry and carbon mass of environmentally relevant prokaryotic microorganisms using a microfluidic mass sensor. We show a significant nonlinear relationship between carbon mass and cell volume and discuss this relationship in the light of currently used cellular mass models.

• Klíčová slova
• bacterioplankton, carbon content, microbial biomass, microorganisms, subsurface,
• MeSH
• Bacteria chemie   MeSH
• biomasa MeSH
• fyziologie bakterií * MeSH
• mořská voda mikrobiologie   MeSH
• půdní mikrobiologie * MeSH
• sladká voda mikrobiologie   MeSH
• uhlík analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• uhlík MeSH

Feces have been suggested as a major source of microorganisms for recolonization of the gut of stored product mites via coprophagy. The mites can host microorganisms that decrease their fitness, but their transmission is not known. To address the role of fecal microbiota on mite fitness, we performed an experimental study in which the surfaces of mite (Tyrophagus putrescentiae) eggs were sterilized. Mites eggs (15 per experimental box) were then hatched and grown on feedstock with and without feces. These experiments were conducted with four distinct T. putrescentiae populations (5L, 5K, 5N, and 5P), and mite population density after 21 day of cultivation was used to assess mite fitness and the impact of fecal microbiota on fitness. Population density was not affected by the presence of feces in two of the cultures (5L and 5K), while significant effects of feces were observed in the other cultures (5N and 5P). Mite culture microbial communities were analyzed using cultivation-independent next-generation amplicon sequencing of microbial 16S and 18S ribosomal RNA (rRNA) genes in the fitness influenced populations (5N and 5P). Several microbial taxa were associated with fecal treatments and reduced mite fitness, including Staphylococcus and Bartonella-like bacteria, and the fungal genera Yamadazyma, Candida, and Aspergillus. Although coprophagy is the transmission route mites used to obtain beneficial gut bacteria such as Bartonella-like organisms, the results of this study demonstrate that fecal-associated microorganisms can have negative effects on some populations of T. putrescentiae fitness, and this may counteract the positive effects of gut symbiont acquisition.

• Klíčová slova
• feces, feeding, microorganisms, mite, transmission, yeasts,
• Publikační typ
• časopisecké články MeSH

Municipal wastewaters can generally provide real-time information on drug consumption, the incidence of specific diseases, or establish exposure to certain agents and determine some lifestyle consequences. From this point of view, wastewater-based epidemiology represents a modern diagnostic tool for describing the health status of a certain part of the population in a specific region. Hospital wastewater is a complex mixture of pharmaceuticals, illegal drugs, and their metabolites as well as different susceptible and antibiotic-resistant microorganisms, including viruses. Many studies pointed out that wastewater from healthcare facilities (including hospital wastewater), significantly contributes to higher loads of micropollutants, including bacteria and viruses, in municipal wastewater. In addition, such a mixture can increase the selective pressure on bacteria, thus contributing to the development and dissemination of antimicrobial resistance. Because many pharmaceuticals, drugs, and microorganisms can pass through wastewater treatment plants without any significant change in their structure and toxicity and enter surface waters, treatment technologies need to be improved. This short review summarizes the recent knowledge from studies on micropollutants, pathogens, antibiotic-resistant bacteria, and viruses (including SARS-CoV-2) in wastewater from healthcare facilities. It also proposes several possibilities for improving the wastewater treatment process in terms of efficiency as well as economy.

• Klíčová slova
• SARS-CoV-2, antibiotic-resistant microorganisms, antimicrobial resistance genes, hospital wastewater treatment, pharmaceuticals,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

BACKGROUND: In recent years, various substrates have been tested to increase the sustainable production of biomethane. The effect of these substrates on methanogenesis has been investigated mainly in small volume fermenters and were, for the most part, focused on studying the diversity of mesophilic microorganisms. However, studies of thermophilic communities in large scale operating mesophilic biogas plants do not yet exist. METHODS: Microbiological, biochemical, biophysical methods, and statistical analysis were used to track thermophilic communities in mesophilic anaerobic digesters. RESULTS: The diversity of the main thermophile genera in eight biogas plants located in the Czech Republic using different input substrates was investigated. In total, 19 thermophilic genera were detected after 16S rRNA gene sequencing. The highest percentage (40.8%) of thermophiles was found in the Modřice biogas plant where the input substrate was primary sludge and biological sludge (50/50, w/w %). The smallest percentage (1.87%) of thermophiles was found in the Čejč biogas plant with the input substrate being maize silage and liquid pig manure (80/20, w/w %). CONCLUSIONS: The composition of the anaerobic consortia in anaerobic digesters is an important factor for the biogas plant operator. The present study can help characterizing the impact of input feeds on the composition of microbial communities in these plants.

• Klíčová slova
• Illumina sequencing, anaerobic digesters, biogas, renewable energy, thermophilic microorganisms,
• MeSH
• anaerobióza MeSH
• bakteriální RNA genetika   MeSH
• biopaliva * MeSH
• mikrobiální společenstva fyziologie   MeSH
• odpadní vody mikrobiologie   MeSH
• RNA ribozomální 16S genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• bakteriální RNA MeSH
• biopaliva * MeSH
• odpadní vody MeSH
• RNA ribozomální 16S MeSH

Home composting can be an effective way to reduce the volume of municipal solid waste. The aim of this study is to evaluate the effect of Effective Microorganism™ (EM) for the home scale co-composting of food waste, rice bran and dried leaves. A general consensus is lacking regarding the efficiency of inoculation composting. Home scale composting was carried out with and without EM (control) to identify the roles of EM. The composting parameters for both trials showed a similar trend of changes during the decomposition. As assayed by Fourier Transform Infrared Spectroscopy (FTIR), the functional group of humic acid was initially dominated by aliphatic structure but was dominated by the aromatic in the final compost. The EM compost has a sharper peak of aromatic CC bond presenting a better degree of humification. Compost with EM achieved a slightly higher temperature at the early stage, with foul odour suppressed, enhanced humification process and a greater fat reduction (73%). No significant difference was found for the final composts inoculated with and without EM. The properties included pH (∼7), electric conductivity (∼2), carbon-to-nitrogen ratio (C: N < 14), colour (dark brown), odour (earthy smell), germination index (>100%), humic acid content (4.5-4.8%) and pathogen content (no Salmonella, <1000 Most Probable Number/g E. coli). All samples were well matured within 2 months. The potassium and phosphate contents in both cases were similar however the EM compost has a higher nitrogen content (+1.5%). The overall results suggested the positive effect provided by EM notably in odour control and humification.

• Klíčová slova
• Effective microorganisms, Food and organic waste composting, Home scale, Humic acid, Nutrient content,
• MeSH
• Escherichia coli * MeSH
• huminové látky * MeSH
• kompostování * MeSH
• půda MeSH
• tuhý odpad MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• huminové látky * MeSH
• půda MeSH
• tuhý odpad MeSH

This review presents selected studies on continuous cultivation including the genetics and selection of microorganisms, production of biomass, liquid fuels and other products, published in 1982-1984 and bearing a relationship to biotechnology.

• Publikační typ
• časopisecké články MeSH

The interaction of house dust mites (HDM) and microorganisms is the key factor in the survival of these mites in human-made environments. Spent growth medium (SPGM) provides the rest of the diet, along with dead mite bodies and microorganisms. SPGM represents a source of microorganisms for the recolonization of mite food and the mite digestive tract. An experiment was performed to observe how adding SPGM to the HDM diet affects HDM population growth, the microbiome composition and the microbial respiration in microcosms. We analyzed American house dust mite (Dermatophagoides farinae) and European house dust mite (Dermatophagoides pteronyssinus) originating from control diets and diets treated with an extract of SPGM from 1- and 3-month-old mite cultures. The microbiome was described using 16S and 18S barcode sequencing. The composition of the bacterial and fungal microbiomes differed between the HDM species, but the SPGM treatment influenced only the bacterial profile of D. farinae. In the D. farinae microbiome of specimens on SPGM-treated diets compared to those of the control situation, the Lactobacillus profile decreased, while the Cardinium, Staphylococcus, Acinetobacter, and Sphingomonas profiles increased. The addition of SPGM extract decreased the microbial respiration in the microcosms with and without mites in almost all cases. Adding SPGM did not influence the population growth of D. farinae, but it had a variable effect on D. pteronyssinus. The results indicated that the HDM are marginally influenced by the microorganisms in their feces.

• Klíčová slova
• diet, feces, feeding, house dust mites, microbiome, microorganisms, mites,
• MeSH
• Dermatophagoides pteronyssinus mikrobiologie   MeSH
• genetická zdatnost MeSH
• kultivační média MeSH
• mikrobiota * MeSH
• populační růst MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Názvy látek
• kultivační média MeSH

Our present in-depth knowledge of the physiology and regulatory mechanisms of microorganisms has arisen from our ability to remove them from their natural, complex ecosystems into pure liquid cultures. These cultures are grown under optimized laboratory conditions and allow us to study microorganisms as individuals. However, microorganisms naturally grow in conditions that are far from optimal, which causes them to become organized into multicellular communities that are better protected against the harmful environment. Moreover, this multicellular existence allows individual cells to differentiate and acquire specific properties, such as forming resistant spores, which benefit the whole population. The relocation of natural microorganisms to the laboratory can result in their adaptation to these favourable conditions, which is accompanied by complex changes that include the repression of some protective mechanisms that are essential in nature. Laboratory microorganisms that have been cultured for long periods under optimized conditions might therefore differ markedly from those that exist in natural ecosystems.

• MeSH
• Bacillus subtilis cytologie   fyziologie   MeSH
• buněčná diferenciace MeSH
• klinické laboratorní techniky MeSH
• příroda * MeSH
• Saccharomyces cerevisiae fyziologie   ultrastruktura   MeSH
• signální transdukce MeSH
• životní prostředí MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH