Cultures Of Microorganisms Research Articles

Genetic profile of antibiotic resistance of enterobacteria strains isolated from obstetrics, gynecology and pediatric patients

Background. Antibiotic resistance of microorganisms is a significant problem for public health in countries around the world. Studying the structure and prevalence of genetic determinants of antibiotic resistance is a current research area that makes it possible to determine the mechanisms of resistance to antibacterial drugs.Purpose of the study. To study the genetic profile of antibiotic resistance of Enterobacteriaceae strains isolated from obstetrics, gynecology and pediatric patients.Materials and methods. The genetic profile of antibiotic resistance was determined in ESBL-producing strains of Enterobacteriaceae isolated from samples of biological material obtained from 43 women and 24 children hospitalized in the departments of the Federal State Budgetary Institution “Research Institute of OMM” of the Russian Ministry of Health in 2024. The DNA of bacterial cells of ESBL-producing isolates was isolated from a daily culture of microorganisms using the PROBA-NK kit. Detection of genes blatem, blactx-M-1, blashv; blaoxa-40-like, blaoxa-48-like, blaоxa-23-like, blaoxa-51-like, blaimp, blaKPS, blaNDM, were carried out using the BakResist GLA kit on a DT-48 detection amplifier (DNA technology, Russia ).Results. In representatives of the Enterobacteriaceae family isolated from children, the blactx-M-1+blashv genovariant was identified in 29.2% of cases and was found only in Klebsiella pneumoniae. Blatem+blactx-M-1 was detected in 20.8%, and blactx-M-1+blashv+blatem — in 12%. Among representatives of the Enterobacteriaceae family isolated from women, the blactx-M-1 genovariant was found in 37.2% of cases and was detected only in Escherichia coli. And the options blactx-M-1+blatem and blactx-M-1+blashv — in 16.3%. In 2024, for the first time in 7 years of our research to identify the genetic determinants of antibiotic resistance, a multidrug-resistant Escherichia coli strain with the blaNDM gene was identified. Also noteworthy is the identification of K. pneumoniae with the genetic profile of antibiotic resistance blatem, blactx-M-1, blashv, blaoxa-48-like, blaNDM.Conclusion. The genetic profile of antibiotic resistance of Enterobacteriaceae strains isolated from patients in obstetrics, gynecology and pediatric departments is represented by 8 genovariants, in which the dominant gene providing resistance to beta-lactam antibiotics among Enterobacteriaceae in 2024, as in 2021, 2022, blaCTX-M-1 remains, which is found both as a monovariant and in association with blatem and blashv.

Legacy Effects of Long-term Straw Returning on Straw Degradation and Microbial Communities of the Aftercrop

Straw incorporation can improve soil fertility and soil structure. While numerous studies have explored the immediate impacts of straw return on soil properties and crop production, the legacy effects of long-term straw return remain less understood. In this study, the straw returning soil of a continuous 15 years （SS） and non-straw returning soil （NS） were collected from Dahe Experimental Station of Hebei Academy of Agriculture and Forestry Sciences in China. The simulation experiments of subsequent straw return were carried out in pots by adding straw to the two types of soil （SS and NS）, in which the degradation rate of straw was determined using the sandbag method, the number of culturable microorganisms was counted through a dilution coating plate, and microbial communities were characterized using high-throughput sequencing. The findings revealed that compared with that in NS, SS significantly increased the degradation rate of 15 d and 30 d straw by 14.16% and 26.57%； the number of soil culturable fungi in 0-60 days by 43.10%-185.92%； and the number of cellulose-degrading bacteria by 55.12%-92.04% at 0 d, 42 d, and 56 d. Additionally, after straw returning for seven days, the bacterial ACE index, fungal ACE index, and Chao1 index in SS were lower than those in NS, indicating that the microbial community richness in SS was significantly reduced. At the phylum level of bacteria, the relative abundances of Acidobacteria, Rokubacteria, and Planctomycetes in SS increased observably, with an increase of 25.92%-45.17%. The relative abundances of the phyla of fungi such as Olpidiomycota, Zoopagomycota, and Glomeromycota increased markedly, with an increase of 12.09%-176.00%. At the genus level of bacteria, the relative abundances of uncultured_bacterium_c_Subgroup_6 and uncultured_bacterium_o_Rokubacteriales in SS increased significantly, with an increase of 28.91%-31.26%, and at the genus level of fungi, the relative abundances of Paecilomyces, Penicillium, and Moesziomyces were significantly increased by 2.98%-8.79%. Network analysis showed the SS bacterial network had a higher interaction degree and network connection, and the fungal network structure was more complex and stable than that of the NS. RDA results showed that soil microbial community composition was significantly correlated with straw degradation rate. SS showed obvious legacy effects on straw degradation, the number of soil culturable microorganisms, and population structure in a certain period, and the microbial flora of SS was more conducive to the degradation of the straws.

Biodiversity of micromycetes isolated from the rhizosphere of halophytic plants of Kazakhstan

This paper presents the results of a study of the biodiversity of soil microscopic fungi isolated in the autumn-summer period from the rhizosphere of halophytic plants growing in the Akmola, Almaty and Turkestan regions (Kazakhstan). To create biopreparations that stimulate growth and protect planting material in forest park zones and horticultural farms, we isolated and identified 352 cultivated microorganisms belonging to the genera Bacillus, Pseudomonas, Arthrobacter, Curtobacterium, Erwinia and others. In total, we studied 8 microscopic fungi. Isolation and cultivation of fungi were carried out on Czapek medium at 28 °С ± 2 °С for 10 days. In addition to using methods for studying the cultural and morphological features of fungi, molecular genetic methods were also used. Identification using the method of comparing nucleotide sequences encoding the 18SрRNA gene of the cultures we isolated showed that their diversity is limited to representatives of only three genera: Fusarium, Alternaria, Penicillium, with the latter two dominating.

Silica hydrogels as a carbon-free solid media for the culture of diverse organisms

Abstract Bacteriological agar plates are commonly used to carry out experiments for the selective growth of microorganisms and the isolation of single-strain colonies. However, the presence of agar itself may be a confounding factor since it may serve as a source of carbon and energy. Moreover, there have been ongoing constraints on the production and sourcing of agar. These concerns have led to an interest in the development of agar substitutes. Silica hydrogels are entirely inorganic carbon-free polymeric materials that lack any source of micronutrients. Herein, a revised method for the preparation of silica hydrogels as a solid culture medium is reported. These gels can be formulated with a range of nutrient-rich or minimal media supplemented with various carbon sources, and can be manipulated in the same manner as agar gels. Their use for the culture and isolation of diverse microorganisms, including both gram-positive and gram-negative bacteria, yeast, and filamentous fungi is demonstrated. These silica hydrogels supplemented with either antibiotics or other molecules of interest can also be used for microbial selection experiments.

Effects of Lactiplantibacillus plantarum on Metabolites and Flavors in Synthetic Microbiota During Baijiu Fermentation.

The distinctive flavor and aroma of Chinese baijiu are closely linked to the microorganisms involved in the fermentation process. Lactiplantibacillus plantarum, a dominant species in the fermentation of Chinese baijiu, has become a prominent research focus. In this study, we selected well-characterized pure cultures of microorganisms to construct diverse chassis microflora. The primary objective was to investigate the effects of L. plantarum on the fermentation process of Chinese baijiu and its association with metabolites produced by different chassis microflora. Our results demonstrated that the concentrations of ethyl lactate and other volatile aromatic compounds increased in all fermentation protocols where L. plantarum was added. The addition of L. plantarum also significantly increased the concentration of total organic acids, particularly lactic acid, which rose by 17 to 123 times. Furthermore, L. plantarum helped maintain the stability of ethanol concentration during the middle and late stages of fermentation. Notably, among the three different chassis microbial fermentation protocols involving L. plantarum, the protocol with the highest microbial diversity exhibited a greater capacity to produce lactic acid (1.56 ± 0.19 mg/g), ethanol (5.74 ± 0.47 mg/g), and reducing sugars (6.39 ± 0.31 mg/g). These findings provide valuable insights into the potential of L. plantarum for modulating the flavor of Chinese baijiu.

Culture of Bacillus subtilis and Saccharomyces cerevisiae from byproducts of the enzymatic extraction of Atlantoraja castelnaui oil

The growing trend in global fish consumption has led to the generation of a large amount of waste and byproducts with negative economic and environmental impacts. The production of fish oil from fish processing residues seems to be a sustainable and future opportunity to provide valuable fatty acids for animal and human consumption. In parallel, this alternative valorization of fish waste has increased the demand to explore sustainable extraction methods. Enzymatic hydrolysis is an efficient, rapid and reproducible method for the extraction of oils from fish guts, producing an aqueous phase rich in proteins and soluble compounds. In this work, a highly soluble aqueous phase obtained from the enzymatic extraction of the liver oil of the ray Atlantoraja castelnaui was tested as a source of nutrient for the growth of Bacillus subtilis and Saccharomyces cerevisiae. Culture media were supplemented with the aqueous phase at a final concentration of 10 mg ml-1 total protein. The growth pattern and biomass yield of yeasts cultured in yeast extract peptone-dextrose (YPD) medium did not show statistically significant differences (p: 0.05) with the diluted medium and the aqueous fraction (AF) supplemented medium. Similar results were obtained for B. subtillis and its positive control in Luria Bertani (LB) medium. In both cases, the ability of these inexpensive media to support the growth of microorganisms was demonstrated. Results suggested that the remaining aqueous phase of the discards from A. castelnaui oil production can be used as an alternative substrate for microorganism culture purposes. In this way, a residue destined for disposal could become a product with added value achieving a good result in the context of circular economy.

Foliar water uptake and phyllosphere microbe colonization increase under higher soil nitrogen availability

Leaf water uptake (FWU) represents an alternative pathway to plant water acquisition that can have positive effects on water and carbon balance. Leaf surface traits including the phyllosphere microbes can affect the leaf wetness capacity and FWU. These functional and structural leaf traits could change depending on soil resources availability. The aim of this study was to evaluate the responses of FWU and leaf surface traits such as contact angle, water drop adhesion (LWA) and phyllosphere-associated microbiota to soil nitrogen addition. Three dominant plant species, Azorella prolifera, Senecio filaginoides, and Papostippa speciosa, of an arid steppe in Patagonia exposed to nitrogen (+N) and nitrogen plus water (+NW) addition for ten years were selected. Leaf contact angle did not exhibit statistical differences among treatments within species. LWA was higher in all treatments with respect to the control (C) for shrub A. prolifera and grass P. speciosa. Nitrogen addition increased significantly FWU in A. prolifera and in P. speciosa with respect to C. Colony-forming units of culturable microorganisms (CFU) on leaf surface responded to N addition, but the changes were statistically significant in S. filaginoides and P. speciosa in +NW, increasing three and eight times, respectively, in relation to the C. A positive linear relationship was found between FWU and LWA across species and treatments. On the other hand, CFU of phyllosphere was negative and exponentially correlated with LWA and FWU, across species and treatments. The results suggest that soil N enrichment could affect functional leaf traits and phyllosphere microbiota in a way that may confer a higher potential to cope with drought by facilitating the use of alternative water sources. On the other hand, we suggested that species with leaves more colonized have less surface exposed for FWU and could have lower wettability depending on the hydrophobicity degree of microbes. However, a higher cover of epiphyte’s microorganisms could compensate the effects of lower FWU by avoiding the leaf dehydration. This study contributes to a better understanding of plant leaf-microbe interactions under higher N atmospheric deposition and intensive fertilization as global agricultural production is expected to increase.

TAXONOMIC COMPOSITION AND PHYSIOLOGICAL AND BIOCHEMICAL PROPERTIES OF CULTIVATED MICROORGANISMS ISOLATED FROM KUDURITE ROCKS OF THE PRIMORSKY KRAI AND THE REPUBLIC OF ALTAI (RUSSIA)

The reason for the consumption of rocks (kudurits) by wild animals has not yet been identified. One of the hypotheses of geophagy is a microbiological factor, i.e. rocks can be a source of microorganisms useful for wild animals. In this work, the composition of cultured microorganisms of kudurits of Primorsky Krai and the Altai Republic, as well as some physiological and biochemical properties of the isolated bacteria were studied using molecular genetic analysis of the 16S RNA gene. It has been shown that the studied breeds contain a high amount of physiological groups of bacteria (saprophytic, ammonifying, nitrifying, silicate, hydrolytic) and yeasts (106-109 cells/ml) useful for animals. Among the isolated culturable microorganisms in the curls of Primorsky Krai, representatives of the genus Pseudomonas, Bacillus, Rhodotorula, Paenibacillus, and Stenotrophomonas predominated. The bacteria of the genus Bacillus, Chryseobacterium, and Streptomyces dominated in the edible soils of Altai. Among the isolates, non-pigmented, motile (35-70%) catalase-positive (86-91%) and oxidase-negative (68-76%) rods (67-90%) predominated. All cultures were characterized by a high level of extracellular enzymatic activity, especially in relation to such substrates as casein (57-75%), starch (57-60%), urea (43-45%). The isolated microorganisms are able to develop in a wide range of temperatures (5-500C), pH (5-12), NaCl concentration (1-18%) and utilize a wide range of carbohydrates and alcohols. It has been established that the microorganisms and biologically active compounds they produce can be a factor that encourages animals to instinctively consume rocks. High antibiotic activity of the isolated cultures has been noted against opportunistic bacteria Staphylococcus aureus, Micrococcus luteus and phytopathogenic fungi Fusarium oxysporum.

Lichen and Its Microbiome as an Untapped Source of Anti-Biofilm Compounds.

Lichen substances have been first described in the 1870s, and around 10000 compounds have been isolated and characterized. Most of them have been evaluated for their activity on planktonic microorganisms (bacteria and fungi). More recently, microorganisms colonizing the lichen thallus have been isolated and identified using DNA sequencing, giving access to a wide diversity of culturable microorganisms. The increasing research in lichen-associated microbiomes in recent years has emphasized a wide range of metabolites as a potential source of bioactive compounds. In parallel, humans are facing microbial resistance to conventional antimicrobial drugs. One of the reasons is the biofilm lifestyle of microorganisms. Indeed, the aggregation of microbial communities inside biofilms is now well known and characterized, and some possible ways to fight and destroy biofilms are identified (quorum sensing inhibitors, etc.). The present review aims to summarize the anti-biofilm potential of lichen metabolites and those from their associated microorganisms (bacteria and/or fungi). Are the metabolites isolated from lichens and their associated fungi displaying any anti-biofilm activity? This literature synthesis highlights the metabolites of interest as new anti-biofilm drugs and shows the lack of current biological research dealing with biofilm and lichen metabolites. Acetone and ethyl acetate extracts are the most studied sources of anti-biofilm agents. Only two lichen metabolites, usnic acid and evernic acid, have been evaluated both as antifungal and antibacterial biofilm compounds. Terpenoids from lichens are still poorly explored for this activity.

Results of the experimental study of the antimicrobial activity of therapeutic waters from various wells managed by the federation of trade unions of Uzbekistan

Introduction. Currently, in addition to the traditional use of mineral waters (MW) for the treatment of gastrointestinal tract and renal diseases, they are also used to correct metabolic disorders, normalize lipid and carbohydrate metabolism. However, many of its properties remain poorly studied, and there is a very limited number of works in the scientific literature concerning the analysis of their antibacterial action. Aim. Study of sensitivity of common microorganisms to the action of some MW. Materials and methods. The following test samples from different wells (DW) served as materials for determining the antimicrobial activity of mineral waters: Sample 1. Sodium bicarbonate weakly alkaline mineral water from SW No. 7 (Chinobod Sanatorium, Tashkent); Sample 2. Radon mineral water mineral water from SW No. 2 (Abu Ali ibn Sino Sanatorium, Samarkand Region); Sample 3. Iodine-bromine mineral water from SW No. 4 (Chartak Sanatorium, Namangan Region); Sample 4. Sulfate-sulfur mineral water from SW No. 14 (Chimen Sanatorium, Fergana Region); Sample 5. Concentrated iodine-bromine brine from SCW No. 2 (Chartak Sanatorium, Namangan Region). Results and discussion. Sample No. 5 (concentrated brine) showed antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa, the diameter of the growth inhibition zone was 22 ± 0.26 and 18 ± 0.35 mm, respectively. Also, sample No. 4 (Sanatorium Chimen DW No = 14, sulfate-sulfur mineral water) showed antimicrobial activity against Staphylococcus aureus, the diameter of the growth inhibition zone was 16 ± 0.11 mm. The samples did not show antimicrobial activity against the other test cultures. The antimicrobial action of water samples was determined by the agar diffusion method against some types of opportunistic bacteria: Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis and the yeast fungus Candida albicans. All microorganism cultures were obtained from the collection of the Institute of Microbiology of the Academy of Sciences of the Republic of Uzbekistan. The determination was achieved through the use of the agar diffusion method on a dense nutrient medium. Conclusion. It was found that sample No. 5 concentrated brine «Iodine-shifo» from the Chartak Sanatorium showed antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa, i. e. Staphylococcus aureus and Pseudomonas aeruginosa, the diameter of the growth inhibition zone was 22 ± 0.26 and 18 ± 0.35 mm, respectively. Also, sample No. 4 sulfate-sulfur mineral water from the Chimen Sanatorium showed antimicrobial activity against Staphylococcus aureus, the diameter of the growth inhibition zone was 16 ± 0.11 mm. The samples did not show antimicrobial activity against the other test cultures.

IDENTIFICATION AND SUSCEPTIBILITY TO ANTIBIOTICS OF BACTERIA ISOLATED FROM MASTITIS MILK FROM THE NORTHERN MESOREGION OF THE STATE OF RIO DE JANEIRO

Milk production is one of the main activities of Brazilian livestock farming. Among the diseases that cause the greatest economic losses to producers, mastitis is the most recurrent. 805 cows were tested using the “California Mastitis Test” (CMT) on 54 farms in the northern mesoregion of the State of Rio de Janeiro. 45.96% (370) tested positive for subclinical mastitis. Milk samples were then collected and subjected to culture and identification of microorganisms according to routine laboratory tests, and an antibiogram was performed shortly thereafter. In 28.4% (105) of the samples, Staphylococcus aureus was identified, followed by 25.1% (93) Streptococcus spp., 10.8% (40) Streptococcus agalactiae, Staphylococcus spp., 8.4% (31), 7.8% (29) Corynebacterium bovis, 0.8% (3) Streptococcus sanguis, 23.2% (86) of the plates with culture medium showed no growth. The antibiogram of 105 strains of Staphylococcus aureus, 83.8% (88) demonstrated resistance to penicillin, it was also observed that 24.7% (26) were resistant to tetracycline. Of the 40 strains of Streptococcus agalactiae, 57.5% (23) were resistant to tetracycline, 18 (45%) were resistant to enrofloxacin and 11 (27.5%) were resistant to gentamicin. The bacteria Staphylococcus aureus, Staphylococcus spp. and Streptococcus agalactiae were the most isolated and showed resistance to antibiotics. These results are of concern for both animal and human health, since Staphylococcus aureus in particular can infect humans.

Removal of terpenes in the presence of easily degradable compounds during biofiltration of gas emissions from composting of municipal solid waste

Composting of the organic fraction of municipal solid waste (OFMSW) is accompanied by the emission of large volumes of harmful, hazardous and foul-smelling volatile organic compounds (VOCs). To improve the efficiency of terpenes removal, which constitute a significant part of VOCs, pure cultures of microorganisms dominating in its microbiota were isolated from the microbial community of the biofilter, which has been cleaning such emissions for a long time. Seven pure cultures were isolated and then tested for being able to grow on a mineral medium in the presence of terpene vapor as the only source of carbon and energy. Three of the most actively growing cultures were selected, characterized and identified by the 16S rRNA gene as Rhodococcus erythropolis CA1, Rhodococcus pyridinivorans CA3 and Gordonia sp. CA6. Three identical laboratory biofilters (BF) were inoculated with a mix of these cultures to test the possibility of more complete removal of terpenes. Biofilters were adapting to clearing the model mix of terpineols and geraniol vapors for 45 days. During 45 days the purification efficiency of the model mix reached an average of 91.5% with a contact time (CT) of 3.7 ± 0.2 s and the terpene vapors concentration of 14 ± 2 mg m−3. Then the biofilters number BF2.1 and BF3.1 were connected to real emission from composting OFMSW. The biofilter BF2.1 purified the emission directly, whereas BF3.1 purified similar discharge after the intermediate biofilter of the 1st stage of purification (BF0.0). The BF1.0 was left connected to purification of the model mix as a control. The effectiveness of biofiltration of hard-to-remove terpenes was evaluated by gas chromatography of samples taken at the inlet and outlet of biofilters. The average efficiency of removing terpenes from real emissions by BF2.1 was 93.1 % (CT = 5.5 s). The total efficiency of removing terpenes by (BF0.0 + BF3.1) complex was 93.2 % (total CT = 7.4 s). A study of the microbiota of inoculated biofilters after 60 and 90 days of purification the real emission by cultivation from dilutions, identification by the 16S rRNA gene and fingerprinting showed that in BF2.1 and BF3.1 Rhodococcus erythropolis CA1 and Rhodococcus pyridinivorans CA3 were preserved among living cells at a level of 6.5–12.4 %, and genetically fully corresponded to the original cultures. These results could have a positive impact on improving the results of deodorization of emissions from OFMSW composting by biofiltration, simplifying the design of the biofiltration facility (one stage instead of two) and reducing the total time for effective biofiltration. This, in turn, would contribute to the wider introduction of highly efficient emission purification methods at OFMSW composting facilities in order to create more comfortable and ecologically clean environmental conditions around them.

Enabling biocontained plant virus transmission studies through establishment of an axenic whitefly (Bemisia tabaci) colony on plant tissue culture

Whiteflies (Bemisia tabaci) and the diseases they transmit are a major detriment to crop yields and a significant contributor to world hunger. The highly evolved interactions of host plant, phloem-feeding insect vector with endosymbionts and persistently transmitted virus represent a tremendous challenge for interdisciplinary study. Presented here is the establishment of a colony of axenic whiteflies on tissue-cultured plants. Efficient colony establishment was achieved by a surface sterilization of eggs laid on axenic phototrophically tissue-cultured plants. The transfer of emerging whiteflies through coupled tissue culture vessels to new axenic plants facilitates robust subculturing and produces hundreds of whitefly adults per month. Whitefly proliferation on more than two dozen plant species is shown as well as in vitro testing of whitefly preference for different plants. This novel multi-organism system provides the high-level of biocontainment required by Federal permitting to conduct virus transmission experiments. Axenic whitefly adults were able to acquire and transmit a begomovirus into tissue-cultured plants, indicating that culturable gut microorganisms are not required for virus transmission. The approach described enables a wide range of hypotheses regarding whitefly phytopathology without the expense, facilities, and contamination ambiguity associated with current approaches.

Sustainable bioethanol production by solid-state fermentation: a systematic review.

The escalation of the global population has accelerated the demand for sustainable energy sources such as bioethanol. Traditionally, bioethanol was obtained by the fermentation of sugar from agricultural crops and grains. However, this technique creates serious threats on the global food supplies, thus hindering the commercial production of bioethanol. Therefore, there is a need to develop new technologies and low-cost raw materials in order to ensure that bioethanol is economically comparable to the first generation of bioethanol. Solid-state fermentation (SSF) has been in the limelight within the scientific community because of its efficiency, cost-effectiveness, and promising technology to produce bioethanol. SSF involves the cultivation of microorganisms on a solid substrate in the absence of free-flowing water, which eliminates the need for sugar extraction and reduces wastewater production. This systematic review provides an overview of the applications of SSF in bioethanol production while presenting recent studies and advancements of this technology for producing sustainable and cost-effective bioethanol.

Effects of bulk forms and nanoparticles of zinc and copper oxides on the abundance, nitrogen cycling and enzymatic activities of microbial communities, morphometric parameters and antioxidant status of Hordeum vulgare L.

Uncontrolled use or improper disposal of bulk forms and nanoparticles of heavy metals may lead to their release into the environment. Coastal and floodplain ecosystems are particularly vulnerable, and the effects of metal nanoparticles on Fluvisol and Stagnic Fluvisol are poorly studied. This study aims to examine the effect of heavy metals on the enzymatic activity of the soil, the abundance of culturable microorganisms, growth, and antioxidant status of H. vulgare L. A model experiment was carried out with contamination of Stagnic Fluvisol Humic and Fluvisol with 2200 and 1320 mg kg-1 Zn and Cu, to assess the ecotoxicity of bulk forms and nanoparticles of ZnO and CuO in floodplain soils. The abundance of culturable microorganisms, namely copiotrophs, prototrophs, oligotrophs and nitrogen fixers increased. However, a sharp decrease in dehydrogenase activity and denitrification occurred. This effect was more pronounced in Fluvisol (7 times) than in Stagnic Fluvisol Humic (3 times). The accumulation of HMs was also higher in plants grown in Fluvisol (16-32 times) than in Stagnic Fluvisol Humic (13-24 times), which led to a decrease in plant growth and activation of antioxidant defense systems. An increase in the level of malondialdehyde, and the activity of superoxide dismutase and catalase indicates the induction of oxidative stress. Heavy metals have a greater impact on the biological properties of Fluvisol compared to Stagnic Fluvisol Humic. The presence of heavy metals boosts the abundance of culturable microorganisms, while nanoparticles hinder plant growth more than bulk heavy metals.

Genomic insights into the cold adaptation and secondary metabolite potential of Pseudoalteromonas sp. WY3 from Antarctic krill.

In the Antarctic marine ecosystem, krill play a pivotal role, yet the intricate microbial community intertwined with these diminutive crustaceans remains largely unmapped. In this study, we successfully isolated and characterized a unique bacterial strain, Pseudoalteromonas sp. WY3, from Antarctic krill. Genomic analysis revealed that WY3 harbors a multitude of genes associated with cold shock proteins, oxidoreductases, and enzymes involved in the osmotic stress response, equipping it with a robust molecular arsenal to withstand frigid Antarctic conditions. Furthermore, the presence of two distinct biosynthesis-related gene clusters suggests that WY3 has the potential to synthesize diverse secondary metabolites, including aryl polyenes and ribosomally synthesized and post-translationally modified peptides. Notably, the identification of genes encoding enzymes crucial for biological immunity pathways, such as apeH and ubiC, hints at a complex symbiotic relationship between WY3 and its krill host. This comprehensive study highlights the robust potential of WY3 for secondary metabolite production and its remarkable ability to thrive at extremely low temperatures in the Antarctic ecosystem, shedding light on the interplay between culturable microorganisms and their hosts in harsh environments, and providing insights into the underexplored microbial communities associated with Antarctic marine organisms and their role in environmental adaptation and biotechnological applications.

Influence of starter cultures of lactic acid bacteria on microbiological parameters and shelf life of sausages

The main spoilage microorganisms of the vacuum-packaged sausages on the first day of chilled storage are the bacteria of the following families: Enterobacteriaceae (Raoultella planticola, Raoultella ornithinolytica, and Citrobacter freundii), Morganellaceae (Morganella morganii) and Staphylococcaceae (Macrococcus caseolyticus), and at the end of the shelf life (on the twenty-first day) - Enterobacteriaceae (Proteus mirabilis, Moellerella wisconsensis and Serratia liquefaciens). An appearance of cloudy juice, surface slime and delamination of the vacuum packaging characterises the sausage spoilage. QMAFAnM in the sausages was increased by 1.09 lg CFU/g and 1.53 lg CFU/g on the first day of storage, by 1.18 lg CFU/g and 1.54 lg CFU/g on the twelfth day, by 0.92 lg CFU/g and 1.96 lg CFU/g on the eighteenth day, respectively, compared to the control sample, because “Vienna sausages with chicken fillet” were treated with starter culture SafePro BLC-48 (Lactobacillus curvatus) or the mixture of starter cultures SafePro BLC-48 (Lactobacillus curvatus) + Bactoferm Rubis (Lactococcus lactis subsp. Lactis) before vacuum packaging. Because the sausages were treated with the mixture of starter cultures SafePro BLC-48 + Bactoferm Rubis, the lactic-acid microorganisms were increased by 0.63 lg CFU/g and 0.53 lg CFU/g on the twenty-fifth and thirtieth days, respectively, compared to the sausages that were treated with SafePro BLC-48. During the entire shelf life, no pathogenic and opportunistic pathogenic bacteria, in particular S. aureus, L. monocytogenes, Salmonella spp., E. coli, coliform bacteria, as well as yeast and mold, were detected in the sausages under all treatment options. The use of starter culture SafePro BLC-48 (Lactobacillus curvatus) or the mixture of starter cultures SafePro BLC-48 (Lactobacillus curvatus) + Bactoferm Rubis (Lactococcus lactis subsp. Lactis) increases the shelf life of the vacuum-packaged sausages if they are kept in a refrigerator for up to 30 days, which is 12 days longer than their shelf life without treatment. The sausage treatment with the mixed starter cultures of the lactic-acid microorganisms may be promising if the development of the aerobic spoilage bacteria is confirmed.

Culturomics: A promising approach for exploring bacterial diversity in natural fermented milk

Natural fermented milk is an abundant source of microbial resources, some of which possess probiotic properties that can help prevent and treat human diseases. However, many potential probiotics have not yet been isolated using traditional pure-culture methods. Culturomics, a relatively novel approach, can be primarily employed to cultivate and identify previously unknown and uncultured bacteria. Nevertheless, their application in natural fermented milk remains limited. Therefore, the primary objective of this study was to evaluate the bacterial diversity in natural fermented milk and explore its microbial potential. For this purpose, we collected three natural fermented milk samples from Inner Mongolia and subjected them to enrichment culture in blood culture bottles for 14 d. Bacterial isolates were obtained from the samples at 0, 3, 7, and 14 days using two culture temperatures and four media, and full-length 16S rRNA gene sequencing was performed for each sample at each time point. The results revealed that 488 strains were isolated from three samples belonging to 3 phyla, 11 genera, and 27 species. The method using two culture temperatures (20 °C and 30 °C) and two media (MRS and RCM + Vb) yielded most of the isolates after 3, 7, and 14 days of enrichment culture. Furthermore, full-length 16S rRNA gene sequencing confirmed that this method significantly increased bacterial diversity in natural fermented milk. In conclusion, the culturomics method demonstrates great potential for the isolation of a greater number of bacterial species and is advantageous for further exploration of the diversity of culturable microorganisms in natural fermented milk.

The effect of biopolymer stabilisation on biostimulated or bioaugmented mine residue for potential technosol production

Mine waste can be transformed into technosol as an ecological strategy. Despite its importance to soil functions, biological activity is often overlooked. Biopolymers can serve as innovative tools for bioremediation, facilitating chemical reactions and creating networks to encapsulate contaminants. This work aims to assess the use of bioleached and stabilised residues from a tungsten mine for technosol production. The first objective was to evaluate mine tailings for their bioleaching potential by biostimulation or bioaugmentation with strain Diaphorobacter polyhydroxybutyrativorans B2A2W2. The second was to evaluate the effect of Portland cement or biopolymers such as Carboxymethyl Cellulose (CMC) or Xanthan Gum (XG) on the stabilisation of bioleached residues. The impact of biopolymers on residues’ characteristics, such as metal leaching, number of cultivable microorganisms, compression strength and ecotoxicity was evaluated using flow systems. Over time, bioleached metallic elements decreased, except for iron (Fe). Biostimulated and stabilised residues exhibited similar trends; both CMC and cement showed low leaching rates and viable microorganisms in the same order (106 CFU × ml−1). However, bioaugmented residue stabilised with XG showed 106 CFU × ml−1 viable microorganisms and increased 2.2-fold Fe leaching than BA_Control. CMC addition to bioaugmented residue reduced 5.9-fold Fe leaching and increased 100-fold viable microorganisms. By utilising both biological and engineering approaches to characterise the technosol, this study contributes to advancing knowledge of technosol production. The residues biostimulated and stabilised with CMC produced a material useful for bio-applications, with low toxicity and metal leaching, useful for bio-applications. XG was the best stabiliser for geotechnical engineering applications, with improved compression strength. In conclusion, the study demonstrates the usefulness of biopolymer treatment for residues and emphasises the importance of selecting the appropriate biopolymer for the intended function of technosols.

Antibacterial and Antifungal Characteristics of Hydroxyl Apatite Composite Material Coated on Nitrogen-doped TiO2 (HA/N-TiO2)

Photocatalytic technology using nano-material HA/TiO2 has been widely applied worldwide to treat pollutants, kill airborne gram-negative and gram-positive bacteria, and candida fungi, especially indoor air. In this study, HA/N-TiO2 material was synthesized with oxidation-reduction absorption properties and photocatalytic ability in the visible-light irradiation that helps reduce costs compared to using ultraviolet light (UV). The structure and morphology of the material were evaluated using XRD, SEM methods, showing HA/N-TiO2 has a spherical crystal structure, sharp, and uniform with particle sizes ranging from 10 to 30 nm. To assessment of the antibacterial and antifungal efficiency of the material, we inoculated the culture of microorganisms on 10x10 cm tiles coated with HA/N-TiO2 solution with the coating thickness of 0.3 µm. This coating thickness resulted in optimal antibacterial efficacy. With continuous fluorescent light 20 W exposure for 1-9 hours, up to 96-100% of inoculated bacteria were eliminated. In real-scale experiments on the wall surfaces, the quantity of bacteria and mold decreased by 20% after 30 days when treated with HA/N-TiO2 solution compared to the control sample. HA/N-TiO2 material has the potential to treat bacteria and fungi on a practical scale if there is further cost-benefit analysis extensive research.