Cultures Of Microorganisms Research Articles

Joining the bacterial conversation: increasing the cultivation efficiency of soil bacteria with acyl-homoserine lactones and cAMP.

Bacteria need to be isolated in pure culture to gain access to the wide array of interesting functions they conceal. This is challenging because they do not live in isolation but instead in communities where they actively communicate and interact with each other. In this study, we aimed to increase the culturability of soil bacteria using three different signaling molecules: N-(3-oxohexanoyl)-L-homoserine lactone, N-octanoyl-L-homoserine lactone, and 3',5'-cyclic adenosine monophosphate (cAMP). The signals were added individually to soils suspended in PBS buffer to a final concentration of 5 µM. Soil suspensions were agitated for 24 hours, after which they were serially diluted and plated on tenfold-diluted Reasoner's 2A agar that either contained or did not contain the same signaling molecule used during the extraction step. DNA was isolated from both soil suspensions and grown cultures and, after a high-throughput amplicon sequencing, differences in bacterial abundances and diversity were determined across treatments. To further explain the action of the signaling molecules on the treated soil communities, their metagenomic functions were predicted using the software PICRUSt2. N-octanoyl-L-homoserine lactone was found to increase the diversity observed on solid media, while N-(3-oxohexanoyl)-L-homoserine lactone and cAMP were not. Potentially novel isolates aided by the signaling molecules were affiliated with the genera Pseudomonas and Nocardioides. IMPORTANCE Microorganisms are a repository of interesting metabolites and functions. Therefore, accessing them is an important exercise for advancing not only basic questions about their physiology but also to advance technological applications. In this sense, increasing the culturability of environmental microorganisms remains an important endeavor for modern microbiology. Because microorganisms do not live in isolation in their environments, molecules can be added to the cultivation strategies to "inform them" that they are present in growth-permissive environmental conditions. Signaling molecules such as acyl-homoserine lactones and 3',5'-cyclic adenosine monophosphate belong to the plethora of molecules used by bacteria to communicate with each other in a phenomenon called quorum sensing. Therefore, including quorum sensing molecules can be an incentive for microorganisms, specifically soil bacteria, to increase their numbers on solid media.

GAS COMPOSITION AND MICROORGANISMS OF GROUND ICE IN RUSSIAN ARCTIC

Link for citation: Butakov V.I., Slagoda E.A., Zavatsky M.D., Ivanov V.I. Gas composition and microorganisms of ground ice in Russian Arctic. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 9, рр. 63-75. In Rus. Relevance. The increase in the concentration of greenhouse gases in the atmosphere is a fundamental problem on a planetary scale. The source of greenhouse gases in the subsurface horizon of soil can be both deep deposits of hydrocarbons and organic matter processed by microorganisms during the thawing of the ice-rich soil. To determine the source of the gas it is necessary to examine both its quantity and composition and the microorganism content in the subsurface ice. Taking into account the dynamic development of the energy complex in the north of Western Siberia it is necessary to take into account the geotechnical risks associated with the release of greenhouse gases from frozen deposits. Purpose: to study the composition and identify the sources of greenhouse gases in the ice and the ice-rich soil on account of the ice formation conditions and the microorganism content. Objects: ice wedge, hydrogenic and segregational genesis of ice, ice-rich soil of northern Western Siberia and Central Yakutia, collected by expeditions Earth Cryosphere Institute, Tyumen scientific center SB RAS in 2011–2021. Methods of research and interpretation of chemical composition. The structure of frozen deposits has been investigated by cryolitological methods. The monoliths of the ice and the frozen deposits were stored at –18 °C. Gas was extracted from the monoliths with the determination of volume fraction by thermovacuum degassing method. The composition of gases is determined by gas chromatography. Normalization of the gas composition with solubility values in water was carried out. Volume fractions of gas in free and dissolved forms was calculated. The data processing were implemented by means of «Geochem Anomaly» program. Cultivated psychrophilic microorganisms were studied by seeding on nutrient media; the total number of microorganisms was determined by epifluorescent microscopy. Results. The contents of N2 (74,9–87,8 %), O2 (11,7–20,3 %), CO2 (0,01–3,28 %), CH4 (0,003–7, 35 %), H2 (0,001–0,035 %) and hydrocarbons with an atom content from 2 to 6 (2,0×10–5–2,8×10–3 %) are determined in ice and ice-rich soil. The value of N2 and O2 in the gas composition of ice is close to atmospheric air. The ice has wide variations in gas saturation (1,1–21,1 %), CH4 and CO2 content. The freezing of gas-saturated solution occurred for the ice formation, part of the air was in a free form (from 30 to 75 %). Calculated indexes CH4/(C2H6+C3H8) and C2H6/C2H4 indicate biogenic hydrocarbon genesis. The composition of gas bubbles is recalculated for the volume of the entire sample: CH4 content is insignificant in ice wedge, closed-cavity ice and icing (averages 51, 81 and 1 ppmV, respectively). The low amounts of CH4 could be produced by forming these types of ice from the sediments of the active layer, as the dependence of the gas composition on the peat element amount is established. CH4, CO2 and H2 contents increased in samples with peat elements. In interbedding ice the CH4 content is high (216 ppmV). CO2 (up to 3007 ppmV) was accumulated in the texturing ice, and hydrogenic wedge-shaped ice showed high levels of CH4 (up to 4032 ppmV) as the ice was frozen in an enclosed volume. The ice of peat mound has a maximum content of CH4 (15545 ppmV) and high CO2 (2466 ppmV); inclosing sediments flooded with marginal-marine waters are the source of high values of CH4 and CO2. The cultivated psychrophilic microorganisms were identified in the surface ice, and their maximum quantities were identified in segregated formations – up to 1680 KOU/ml, in textural ice – up to 1032 KOU/ml. High concentrations of greenhouse gases are found in frozen peat – CO2 (1075 ppmV), H2 (9 ppmV), CH4 (262 ppmV) and other hydrocarbons due to activity of microorganisms, which results in accumulation of these gases. High gas saturation and CH4 and CO2 levels indicate the formation of gaseous composition by both aerobic and anaerobic microorganisms.

Potential for the anaerobic oxidation of benzene and naphthalene in thermophilic microorganisms from the Guaymas Basin.

Unsubstituted aromatic hydrocarbons (UAHs) are recalcitrant molecules abundant in crude oil, which is accumulated in subsurface reservoirs and occasionally enters the marine environment through natural seepage or human-caused spillage. The challenging anaerobic degradation of UAHs by microorganisms, in particular under thermophilic conditions, is poorly understood. Here, we established benzene- and naphthalene-degrading cultures under sulfate-reducing conditions at 50°C and 70°C from Guaymas Basin sediments. We investigated the microorganisms in the enrichment cultures and their potential for UAH oxidation through short-read metagenome sequencing and analysis. Dependent on the combination of UAH and temperature, different microorganisms became enriched. A Thermoplasmatota archaeon was abundant in the benzene-degrading culture at 50°C, but catabolic pathways remained elusive, because the archaeon lacked most known genes for benzene degradation. Two novel species of Desulfatiglandales bacteria were strongly enriched in the benzene-degrading culture at 70°C and in the naphthalene-degrading culture at 50°C. Both bacteria encode almost complete pathways for UAH degradation and for downstream degradation. They likely activate benzene via methylation, and naphthalene via direct carboxylation, respectively. The two species constitute the first thermophilic UAH degraders of the Desulfatiglandales. In the naphthalene-degrading culture incubated at 70°C, a Dehalococcoidia bacterium became enriched, which encoded a partial pathway for UAH degradation. Comparison of enriched bacteria with related genomes from environmental samples indicated that pathways for benzene degradation are widely distributed, while thermophily and capacity for naphthalene activation are rare. Our study highlights the capacities of uncultured thermophilic microbes for UAH degradation in petroleum reservoirs and in contaminated environments.

Happi: a hierarchical approach to pangenomics inference

Recovering metagenome-assembled genomes (MAGs) from shotgun sequencing data is an increasingly common task in microbiome studies, as MAGs provide deeper insight into the functional potential of both culturable and non-culturable microorganisms. However, metagenome-assembled genomes vary in quality and may contain omissions and contamination. These errors present challenges for detecting genes and comparing gene enrichment across sample types. To address this, we propose happi, an approach to testing hypotheses about gene enrichment that accounts for genome quality. We illustrate the advantages of happi over existing approaches using published Saccharibacteria MAGs, Streptococcus thermophilus MAGs, and via simulation.

Enzymes of microorganisms. Proteases of lactic acid bacterias

The work is devoted to the enzymes of microorganisms. This review article presents the characteristics of microbial enzymes, their classifications according to various parameters. The study examines the role of microbial enzymes in various areas of human life. Enzymes are involved in the biochemical processes of microorganisms for their protection, reproduction, and growth. Enzyme producers are various taxonomic groups of bacteria, filamentous fungi, actinomycetes and yeasts. The article describes hydrolytic enzymes, reveals the importance of the protease enzyme involved in various processes with microorganisms. The main producers of proteolytic enzymes are bacteria of the genus Bacillus, Lactobacillus, Streptococcus, Micrococcus, Pseudomonas, fungi of the genus Aspergillus, Penicillium, Blakeslea, actynomicetes of the genus Streptomyces, Actinomyces. Particular attention is paid to lactic acid bacteria. The significance of the use of protease in the biotechnological industry, in particular, for the development of preparations, starter cultures, bioadditives, and functional food products with desired properties, is shown. The article mentions the results of a study of the proteolytic activity of cultures of microorganisms, obtained by me and my colleagues. The objects of study were bacilli, yeast, fungi and lactic acid bacteria.To assess proteolytic activity, in vitro methods, chromatographic and other methods are used.

Enhanced biodegradation of phenol by microbial collaboration: Resistance, metabolite utilization, and pH stabilization

Mixed culture of microorganisms is an effective method to remove high concentration of phenol from wastewater. Currently, the mechanism of how microorganisms collaborate to enhance the biodegradation of phenol is still a challenge. In this study, the isolated Bacillus subtilis ZWB1 and Bacillus velezensis ZWB2 were co-cultured to enhance phenol biodegradation, and the mechanism of microbial collaboration was further explored. The co-culture of strains could significantly increase the rate (16.7 mg/L·h, 1000 mg/L) and concentration of phenol degradation (1500 mg/L), comparing with mono-culture of ZWB1 (4.2 mg/L·h, 150 mg/L) and ZWB2 (6.9 mg/L·h, 1000 mg/L), among which the highest degraded concentration of phenol for ZWB1 and ZWB2 was 150 and 1000 mg/L. Further, the mechanism of microbial collaboration to enhance phenol biodegradation was raised: the decrease of antioxidant enzymes, and increase of degrading enzymes and surfactants on content after co-culture, assisted the microorganisms in withstanding phenol; Bacillus subtilis ZWB1 used the metabolites of Bacillus velezensis ZWB2 to promote its growth, and further to degrade phenol rapidly; Bacillus subtilis ZWB1 alleviated the damage, which resulted from the pH drop (5.8) of the fermentation broth during phenol degradation that inhibited the growth and degraded ability of Bacillus velezensis ZWB2, making the pH of fermentation broth stable at 7. Metabolic analysis showed that co-culture of strains could produce more alkaline and buffering compounds and pairs, to stabilize pH and reduce the toxicity of acidity on ZWB2, thus increasing the degradation rate. This study explains the mechanism of microbial collaboration on phenol biodegradation from multiple perspectives, especially pH stabilization, which provides a theoretical basis for the degradation of pollutants by co-culture microorganisms.

Bacteriological monitoring of poultry (chickens, turkeys) and compound feed for their diet in Ukraine

The article presents the results of studies conducted during 2021 on the circulation of bacterial pathogens among poultry (chickens, turkeys) from industrial and private households in Ukraine, as well as the microbiological contamination of feed and components for their production. 138 isolates of bacterial cultures were isolated from chickens in poultry farms of various forms of ownership, and 12 cultures of microorganisms were isolated from turkeys of different ages in private households. The circulation of a wide range of microorganisms from the families Enterobacteriaceae, Staphylococcaceae, Enterococcaceae, Pseudomonadaceae, Clostridiaceae, Mycoplasmataceae was established in poultry, in particular, three isolates of the causative agent of toxic infections – Salmonella Enteritidis were isolated. 31.4% (16 samples out of 51 tested) of compound feed and their components did not comply with the quality and safety criteria. The main bacterial contaminants of the feed were conditionally pathogenic microorganisms of the Enterobacteriaceae, Bacillaceae, Pseudomonadaceae, Enterococcaceae and Staphylococcaceae families. In addition, a culture of Salmonella spp. was isolated from one feed sample. In the future our researches may be directed to the role of the natural reservoir of pathogens (especially poultry and wild birds) in the formation of antibiotic resistant forms of bacteria

The impact of mineral and organic supplements on the abundance of selected groups of culturable microorganisms in soil contaminated with heavy metals

The impact of mineral and organic supplements on the abundance of selected groups of culturable microorganisms in soil contaminated with heavy metals

Decolorization potential of malachite green by Ralstonia mannitolilytica isolated from Indonesian cassava-based fermentedfoodtapai.

Pollution due to textile dye effluent mishandling is hazardous to ecosystems and to the living beings inhabiting them. This can cause retarded photosynthesis, disrupted fish day/night cycles, unbalanced bacterial populations, and decreased oxygen concentration in contaminated water, leading to low habitability. In this study, we aimed to isolate and characterize the microorganisms found in Indonesian cassava-based fermented food tapai starter cultures as a source of potential microbes for the biological remediation of textile dye pollutants. Microorganisms in the tapai starter culture were screened for their decolorization activity via spread-culture inoculation on a solid growth medium supplemented with textile dyes. Isolated microorganisms were selected based on their ability to secrete textile dye-decolorizing extracellular enzymes via increased light penetration after incubation of the cell-free supernatant (CFS) containing extracellular enzymes in textile dye solutions. Isolate JSP1 was the only bacterium capable of producing malachite green (MG)-decolorizing extracellular enzymes, which enabled it to survive and decolorize MG up to 375ppm. Moreover, isolate JSP1 CFS was able to optimally decolorize 75% of MG at 100ppm, but its activity was diminished at concentrations > 350ppm. Colony and cellular morphology, biochemistry, and 16S rRNA tests revealed that the isolate was of Ralstonia mannitolilytica. Therefore, R. mannitolilytica isolate JSP1 may be a potential bioremediation agent for MG.

Effects of Anthropogenic Disturbance and Seasonal Variation on Aerobiota in Highly Visited Show Caves in Slovenia.

Aerosols in caves are natural tracers and, together with climatic parameters, provide a detailed insight into atmospheric conditions, responses to climatic changes and anthropogenic influences in caves. Microbiological air monitoring in show caves is becoming increasingly useful to understand changes in cave ecosystems and to implement and review measures for sustainable cave use and tourism development. In 2017 and 2018, air along tourist trails in caves Postojnska jama and Škocjanske jame (Slovenia) was sampled before and after tourist visits. Samples were analysed using culture-dependent methods, flow cytometry, detection of β-D-glucan and lipopolysaccharide and compared with CO2 and temperature data to measure anthropogenic influences and seasonality on aerobiota. While the presence of tourists significantly increased concentrations of airborne microorganisms (p < 0.05), β-D-glucan and CO2 did not show such a trend and were more dependent on seasonal changes. Locally, concentrations of cultivable microorganisms above 1000 CFU/m3 were detected, which could have negative effects on the autochthonous microbiota and possibly on human health. A mixture of bacteria typically associated with humans was found in the air and identified with MALDI-TOF MS. Using MALDI-TOF MS, we achieved a 69.6% success rate in identification. Micrococcus luteus, Streptococcus mitis, Staphylococcus epidermidis and Moraxella spp. were recognized as good indicators of cave anthropisation.

Genetic determinants of antibiotic resistance in enterobacteria isolated during microbiological monitoring in the perinatal center

Relevance. Currently, studies of the prevalence of antibiotic resistance and its genetic characteristics are focused primarily on the adult population, although infection with multiple drug infection has been registered as etiological agents of a general infection in obstetric and gynecological and pediatric institutions. The study of the prevalence of genetic determinants of antibiotic resistance is an important area of scientific research.Aim. To analyze the results of the studies carried out to identify the genetic determinants of antibiotic resistance of enterobacteria isolated during microbiological monitoring in the perinatal center.Materials and methods. The genetic profile of antibiotic resistance was studied in ESBL-producing strains isolated from 45 women and 35 children examined at the departments of the Federal State Budgetary Institution «NII OMM» of the Ministry of Health of Russia. To determine the determinants of antibiotic resistance, 80 non-duplicate strains of 7 species of the Enterobacteriaceae family were studied. DNA of bacterial cells was isolated from a daily culture of microorganisms using the PROBA-NK kit, detection of the tem, ctx-M-1, shv genes; oxa-40-like, oxa-48-like, oxa-23-like, oxa-51-like, imp, kpc, ges, ndm, vim were carried out using the diagnostic kit «BacResista GLA» on the detecting amplifier DT-48 (DNA -technology, Russia). To assess the statistical significance of differences in the frequency of occurrence of genes, Pearson's c2 test with Yates' correction was used.Results and discussion. When analyzing the results of studies on the molecular genetic detection of antibiotic resistance determinants, which we conducted in 2022, it was found that 8 genovariants were found in bacterial strains isolated from patients of the departments of the Research Institute of OMM in Yekaterinburg, providing resistance to beta-lactam antibiotics. The dominant genome, as in 2021, remains blaCTX-M-1, found in 29 cases. The blaTEM gene was identified both in association with other genes and as a single variant in Escherichiae coli and Klebsiella pneumoniae strains. Of the eight strains of K. pneumoniae, 4 were found to have three antibiotic resistance genes blaCTX-M, blaTEM, blaSHV, strains with a genetic profile of blaCTX-M, blaTEM, blaSHV, blaNDM were isolated once; and blaTEM, blaSHV, blaKPC. In one strain of K. pneumoniae, phenotypically showing resistance to AB, no genetic determinants of AB resistance were found. In addition to resistance to beta-lactam antibiotics, the strains demonstrate resistance to such groups of antibacterial drugs as fluoroquinolones, phosphonic acid derivatives (fosfomycin), and aminoglycosides. The data obtained indicate that the intestines of newborns during their stay at the stationary stage of nursing in some cases are colonized by strains of enterobacteria with multidrug resistance. Consequently, children are a reservoir of resistant microorganisms and can be sources of pathogens of infectious diseases in families and children's organized groups.

Screening of Bacteria Isolated from Arctic Atmospheric Aerosols for Oil Degradation Ability

Currently, a significant part of the world's soil cover is exposed to negative pollution, leading to its degradation. Oil hydrocarbons play a significant role among numerous soil pollutants. Sources of pollution are enterprises of oil extraction, oil refining, oil and oil products transportation. Every year in the world millions of tons of oil and oil products are lost during extraction, transportation, storage and use. Biological remediation based on the potential of microorganisms to transform pollutants of different origin is the most promising and environmentally safe method of restoring soil fertility, so the search for new strains to create and improve such biological preparations is still relevant. Atmospheric aerosols are a source of both transient and endogenous microbiota, which are metabolically active in relation to pollutants. During a complex airborne expedition on atmospheric sounding over the Arctic Ocean seas samples of aerosols were collected for microbiological analysis. The isolated cultures of microorganisms belonging to the genera Bacillus, Acinetobacter, Rhodococcus were tested for the ability to oil destruction when growing on agarized and liquid medium with the addition of oil to 2% as the only source of carbon and incubation for 10 days. The bioemulsifying and biodegrading abilities of microorganisms during growth in liquid medium were estimated visually by destruction of the surface film of oil, turbidity of the nutrient medium due to an increase in the biomass of microorganisms, formation of a uniform emulsion of oil in the medium, microscopy of cultural suspensions, and by their seeding on agarized nutrient medium to determine the titer of viable cells. Highly effective mesophilic and psychrotolerant oil destructor bacteria were isolated from northern atmospheric aerosols, which can be used to create complex biopreparations capable of assimilating a wider range of oil hydrocarbons for remediation of polluted soils and grounds in cold territories of Siberia and the Arctic.

Harnessing the potential of microalgae-bacteria interaction for eco-friendly wastewater treatment: A review on new strategies involving machine learning and artificial intelligence

In the pursuit of effective wastewater treatment and biomass generation, the symbiotic relationship between microalgae and bacteria emerges as a promising avenue. This analysis delves into recent advancements concerning the utilization of microalgae-bacteria consortia for wastewater treatment and biomass production. It examines multiple facets of this symbiosis, encompassing the judicious selection of suitable strains, optimal culture conditions, appropriate media, and operational parameters. Moreover, the exploration extends to contrasting closed and open bioreactor systems for fostering microalgae-bacteria consortia, elucidating the inherent merits and constraints of each methodology. Notably, the untapped potential of co-cultivation with diverse microorganisms, including yeast, fungi, and various microalgae species, to augment biomass output. In this context, artificial intelligence (AI) and machine learning (ML) stand out as transformative catalysts. By addressing intricate challenges in wastewater treatment and microalgae-bacteria symbiosis, AI and ML foster innovative technological solutions. These cutting-edge technologies play a pivotal role in optimizing wastewater treatment processes, enhancing biomass yield, and facilitating real-time monitoring. The synergistic integration of AI and ML instills a novel dimension, propelling the fields towards sustainable solutions. As AI and ML become integral tools in wastewater treatment and symbiotic microorganism cultivation, novel strategies emerge that harness their potential to overcome intricate challenges and revolutionize the domain.

The microscopic structure of pork neck after cooling with showering stiving and processing by culture Lactobacillus sakei

Microstructural changes in meat that occur during refrigerated storage depend on the hygiene of slaughtering and primary processing of animal carcasses, their cooling conditions, storage period, and microbial contamination and reflect the processes of meat maturation and spoilage. To extend the shelf life of pork in half-carcasses in a chilled state, 20 heads of 6-month-old large white pigs were used, which were delivered to the meat processing enterprise for slaughter. All half carcasses were cooled in a refrigerating chamber using showering, 1 hour later they were divided into 2 groups: control (without treatment) and experimental with the final treatment with a suspension of lactic acid bacteria of the SafePro® B-2 strain (Lactobacillus sakei). It has been found that cooling of pork half-carcasses in a refrigerating chamber with stiving and final processing by a culture suspension of lactic-acid microorganisms of strain SafePro® B-2 (Lactobacillus sakei) on the 4th day of storage had a positive effect on the microscopic structure of the pork neck and was characterized by a uniform color distribution when histologic specimens of muscular tissue are colored with hematoxylin and eosin, and minor cracks in the sarcoplasm, preservation of transverse and longitudinal striation of muscular fibers in comparison with that of the unprocessed pork half-carcasses with cultures of lactic-acid microorganisms. The microscopic structure of the muscular tissue of the pork half-carcass neck after cooling with stiving and final processing by a culture of lactic-acid microorganisms of strain SafePro® B-2 for 7 days of storage had a more distinct histoarchitecture in comparison with that of the unprocessed pork half-carcasses, as well as was characterized by insignificant areas of muscular fibers with transverse cracks, suspended development period of autolysis processes, partial preservation of transverse and longitudinal striation of muscle fibers. This points to a positive effect of lactic acid bacteria of strain SafePro® B-2 (Lactobacillus sakei) on the quality of the pork meat and contributes to the extension of its shelf life under chilled vintage.

Nanostructured sol-gel bioactive glass 60S: In vitro study of bioactivity and antibacterial properties in combination with vancomycin

Nanostructured samples of bioactive glass 60S (BG 60S) with a composition (mol %) of 60% SiO2, 36% CaO, 4% P2O5 were synthesized by the sol-gel method in this research. The bioactivity of the synthesized material was evaluated by in vitro assays. The dynamics of the formation of hydroxyapatite (HA), contributing to the formation of effective bonds with bones and soft tissues during immersion in a simulated body fluid (SBF Kokubo), was evaluated using FTIR, XRD, and SEM-EDX. Changes of the specific surface values, particle size and zeta potential for soaked samples in SBF were also investigated. Determination of the antibacterial activity of BG 60S/vancomycin composites was carried out on test cultures of gram-positive microorganisms being one of the most frequent etiological factors of infectious complications in injuries – Staphylococcus aureus. The effectiveness of the release of the antibiotic was confirmed by determining the zone of inhibition of the test culture using the modified Kirby–Bauer disk diffusion method. It is shown that BG 60S/vancomycin composites are characterized by the preservation of antibacterial properties of vancomycin with its prolonged release, and osteoconductive properties, which are inherent in bioactive sol-gel glass and are promising for practical use in the surgical treatment of bone diseases. Based on the foundings, it is possible to suggest a positive effect of the joint application of BG 60S and vancomycin as part of composites with an effective combination of the functions of bone tissue restoration, treatment and prevention of postoperative infectious complications.

Research Progress of α-Glucosidase Inhibitors Produced by Microorganisms and Their Applications.

Based on the easy cultivation of microorganisms and their short cycle time, research on α-glucosidase inhibitors (α-GIs) of microbial origin is receiving extensive attention. Raw materials used in food production, such as cereals, dairy products, fruits, and vegetables, contain various bioactive components, like flavonoids, polyphenols, and alkaloids. Fermentation with specific bacterial strains enhances the nutritional value of these raw materials and enables the creation of hypoglycemic products rich in diverse active ingredients. Additionally, conventional food processing often results in significant byproduct generation, causing resource wastage and environmental issues. However, using bacterial strains to ferment these byproducts into α-GIs presents an innovative solution. This review describes the microbial-derived α-GIs that have been identified. Moreover, the production of α-GIs using industrial food raw materials and processing byproducts as a medium in fermentation is summarized. It is worth analyzing the selection of strains and raw materials, the separation and identification of key compounds, and fermentation broth research methods. Notably, the innovative ideas in this field are described as well. This review will provide theoretical guidance for the development of microbial-derived hypoglycemic foods.

Research on the incidence of infectious urocystitis in dogs and cats and their main causative agents

Urocystitis is the most common disease of the urinary tract, which has different etiology and can be complicated by bacterial microflora. There are many factors that can contribute to the occurrence of bacterial urocystitis in small animals: chronic inflammatory processes of non-infectious origin, urolithiasis, localization of the bacterial focus in the organs and tissues adjacent to the urethra. Often, during the course of urocystitis, bacteria play the role of a complicating factor or are the main cause of infectious urocystitis in dogs and cats. Therefore, microorganisms that penetrate through the urethra into the bladder can be both gram-positive or gram-negative, highly pathogenic or conditionally pathogenic, which, under favorable conditions created during the course of inflammation, begin to pose a danger to a sick animal. Their identification and determination of resistance to antibiotics is the key to quality treatment and quick recovery during the course of bacterial urocystitis. While the differentiation of infectious from non-infectious urocystitis makes it possible to prevent the irrational use of antibiotics in veterinary practice and to prevent the formation of multiresistant bacterias to different groups of antibiotics. In order to find out the percentage ratio of infectious and non-infectious urocystitis, to determine the species composition of the microflora and its sensitivity to antibiotics of different groups, an aseptic urine sample was taken from animals with urocystitis. Initially, after obtaining the material for examination, urine was subjected to microscopy, followed by cultivation and determination of sensitivity to antibiotics of all obtained cultures of microorganisms. The study was conducted on 82 sick cats and dogs. Of all tested samples, 70.7 % had no growth on nutrient media during the cultivation, while 29.3 % had bacterial growth on meat peptone agar, meat peptone broth, and blood agar. This indicates that almost every third animal under study has bacterial urocystitis, which requires treatment with antibiotics. During cultivation was found the largest number of cultures of Enterococcus spp. and Escherichia coli, which show sensitivity to fluoroquinolone antibiotics (enrofloxacin, ofloxacin, ciprofloxacin) and cephalosporins (cefazalin, cephalexin, and ceftriaxone).

Quantification and modeling of macroparticle-induced mechanical stress for varying shake flask cultivation conditions.

In biotechnological processes, filamentous microorganisms are known for their broad product spectrum and complex cellular morphology. Product formation and cellular morphology are often closely linked, requiring a well-defined level of mechanical stress to achieve high product concentrations. Macroparticles were added to shake flask cultures of the filamentous actinomycete Lentzea aerocolonigenes to find these optimal cultivation conditions. However, there is currently no model concept for the dependence of the strength and frequency of the bead-induced stress on the process parameters. Therefore, shake flask simulations were performed for combinations of bead size, bead concentration, bead density and shaking frequency. Contact analysis showed that the highest shear stresses were caused by bead-bottom contacts. Based on this, a newly generated characteristic parameter, the stress area ratio (SAR), was defined, which relates the bead wall shear and normal stresses to the total shear area. Comparison of the SAR with previous cultivation results revealed an optimum pattern for product concentration and mean product-to-biomass related yield coefficient. Thus, this model is a suitable tool for future optimization, comparison and scaling up of shear-sensitive microorganism cultivation. Finally, the simulation results were validated using high-speed recordings of the bead motion on the bottom of the shake flask.

A Model of Acute Peritonitis.

The biological models used in the study of generalized peritonitis can be subdivided into 5 groups (introduction of foreign bodies, cultures of microorganisms, suspensions of feces, chemicals, and mechanical damage to the gastrointestinal tract) or into 4 groups (introduction of foreign bodies, chemicals, bacterial contamination of the abdominal cavity, and combined methods). After analysis of published reports, the most justified classification of methods of peritonitis modelling is based on the type of peritonitis-inducing agent and the administration route and on the nature of peritonitis developing in the abdominal cavity. The choice of the model maximally close reproducing clinical conditions of peritonitis should be based on the specific objectives of the study, focusing on the etiology, pathogenesis, and severity of the disease course, planned measures aimed at eliminating the process, and other factors.

Properties of actinomycetes from the rhizosphere of Colobanthus quitensis (Kunth) Bartl. (Booth Island, maritime Antarctica)

Aim. Investigate the biological properties of actinomycetes from the rhizosphere of Colobanthus quitensis (Kunth) Bartl. and study their ability to produce bioactive compounds. Methods. Microbiological (isolation, synthesis of bioactive compounds), genetic and genetic engineering (isolation and analysis of total DNA, DNA gel electrophoresis, polymerase chain reaction, DNA sequencing), bioinformatic (phylogenetic analysis) methods. Results. 21 actinomycete isolates were obtained from the samples of C. quitensis rhizosphere. Half of the isolates exhibited antagonistic properties towards at least one of 17 test cultures of pathogenic and phytopathogenic microorganisms. Some strains exhibited both antibacterial and antifungal activities. The majority of isolates (70-95 %) produced proteases, amylases, cellulases, almost 42 % – nitrate reductases, 20-25 % – pectinases and lipases, respectively. Conclusions. A collection of Antarctic actinomycetes has been created and characterized, which is promising for evaluating their metabolic potential as producers of antibiotics.