Aflatoxin B1 (AFB1) is a natural toxin produced by many food-contaminant fungi and is a threat to human and animal health. This review summarizes current knowledge of the different ways to limit AFB1 ...in the food chain. We start by introducing current data and reviews available on the prevention of AFB1 occurrence, on AFB1 non-biological decontamination and biological adsorption. We then focus on microbial AFB1-degradation. The latter has already been well studied using living organisms, supernatants or purified enzymes. This review compiles information on the variety of protocols and the efficacy of the different sub-kingdoms or classes of microorganisms or their enzymes. We pay particular attention to publications closest to in vivo applications of microbial AFB1-degradation.
In addition, this review also provides a summary of the currently known microbial degradation metabolites of AFB1 and their levels of toxicity, and provides recommendations on the most promising techniques to pursue the aim of minimizing ABF1 in the food supply.
•Review on AFB1 microbial degradation•Special focus on close to in vivo application•Proposed insights on how to realize future AFB1-degradation tests
Sinking of organic matter represents an essential mechanism for sequestration of carbon that is exported from the ocean surface to deeper depths. While recent studies have highlighted the important ...role of microorganisms in the biological pump, the impact of sinking particles on the vertical connectivity of microbial communities has received limited attention. In this study, we present the microbial profile of sinking particles in the northern slope and the central basin of the marginal South China Sea (SCS) using an in-line size-fractionated water filtration and Illumina high-throughput 16S rRNA amplicon sequencing. We investigate the microbial community composition within organic particles of different size fractions (30, 5, 3, 0.22 μm), and we reveal significant differences in the microbial community structure between these two distinct areas of SCS. The vertical connectivity of microbial communities in the slope and the central basin of SCS shows distinct patterns of microbial dispersal along the water column that occurs via the sinking of organic particles. We find that the microbial communities have different abundances on the different examined particle size fractions and which highlights the role of sinking particles in shaping microbial lifestyles along the water column. Our study underscores the influence of environmental variations on the vertical connectivity of microorganisms and provides additional insights into the marine biological pump under different environmental conditions.
•Differences in prokaryotic communities and their vertical connectivity between South China Sea slope and central basin.•Differences in particle characterization in two regions affect the vertical connectivity of prokaryotic community.•Depth-specialist ASVs and ASVs shared across all depths show different particle size preferences.
Free-living microorganisms may become suitable models for recovery of non-essential and essential heavy metals from wastewater bodies and soils by using and enhancing their accumulating and/or ...leaching abilities. This review analyzes the variety of different mechanisms developed mainly in bacteria, protists and microalgae to accumulate heavy metals, being the most relevant those involving phytochelatin and metallothionein biosyntheses; phosphate/polyphosphate metabolism; compartmentalization of heavy metal-complexes into vacuoles, chloroplasts and mitochondria; and secretion of malate and other organic acids. Cyanide biosynthesis for extra-cellular heavy metal bioleaching is also examined. These metabolic/cellular processes are herein analyzed at the transcriptional, kinetic and metabolic levels to provide mechanistic basis for developing genetically engineered microorganisms with greater capacities and efficiencies for heavy metal recovery, recycling of heavy metals, biosensing of metal ions, and engineering of metalloenzymes.
The article is devoted to the latest achievements in the field of research, development, and implementation of various types of medicinal products based on recombinant probiotics. The benefits of ...probiotics, their modern use in medicine along with the most frequently used genera and species of probiotic microorganisms were highlighted. The medicinal and therapeutic activities of the studied probiotics were indicated. The review suggests various methods of creating recombinant probiotic microorganisms, including standard genetic engineering methods, as well as systems biology approaches and new methods of using the CRISPR-Cas system. The range of potential therapeutic applications of drugs based on recombinant probiotics was proposed. Special attention was paid to modern research on the creation of new, more effective recombinant probiotics that can be used for various therapeutic purposes. Considering the vast diversity of therapeutic applications of recombinant probiotics and ambiguous functions, their use for the potential treatment of various common human diseases (non-infectious and infectious diseases of the gastrointestinal tract, metabolic disorders, and allergic conditions) was investigated. The prospects for creating different types of vaccines based on recombinant probiotics together with the prospects for their implementation into medicine were considered. The possibilities of using recombinant probiotics in veterinary medicine, particularly for the prevention of domestic animal diseases, were reviewed. The prospects for the implementation of recombinant probiotics as vaccines and diagnostic tools for testing certain diseases as well as modeling the work of the human digestive system were highlighted. The risks of creation, application, including the issues related to the regulatory sphere regarding the use of new recombinant microorganisms, which can potentially enter the environment and cause unforeseen circumstances, were outlined.
Стаття присвячена сучасному стану досягнень у сфері досліджень, розробки та впровадження різних видів медичних препаратів на основі рекомбінантних пробіотиків. Висвітлено переваги пробіотиків, їх сучасне використання у медицині, проаналізовано найчастіше використовувані роди та види пробіотичних мікроорганізмів. Наведено лікувально-терапевтичні активності досліджених пробіотиків. Огляд ознайомлює з різними методами створення рекомбінантних пробіотичних мікроорганізмів, серед яких як стандартні методи генної інженерії, так і підходи системної біології та нові методи з використанням системи CRISPR-Cas. Наведено спектр потенційних терапевтичних застосувань препаратів на основі рекомбінантних пробіотиків, особливу увагу приділено сучасним дослідженням зі створення нових більш ефективних рекомбінантних пробіотиків, що можуть бути використані з різними терапевтичними цілями. Зважаючи на різноманітні можливості терапевтичного застосування рекомбінантних пробіотиків та їх неоднозначну функціональність, розглянуто їх використання для потенційного лікування різних поширених захворювань людини: не- та інфекційних хвороб шлунково-кишкового тракту, метаболічних розладів, алергічних станів. Розглянуто перспективи створення різних типів вакцин на основі рекомбінантних пробіотиків та перспективи їх впровадження у медицину. Оцінено перспективи застосування рекомбінантних пробіотиків у ветеринарії, особливо для профілактики захворювань свійських тварин. Висвітлюється перспектива впровадження рекомбінантних пробіотиків як вакцин і діагностичних засобів для тестування певних хвороб та моделювання роботи травної системи людини. Окремо розглянуто ризики створення та застосування й проблематику нормативної сфери щодо використання нових рекомбінантних мікроорганізмів, які потенційно можуть потрапити в навколишнє середовище і викликати непередбачені ситуації.
This brief historical development of the biology of the mycoplasmas begins with their discovery in 1898 to the present. Mycoplasmas are the smallest free-living microorganisms and for years were ...thought to be viruses because they passed through the usual bacterial filters. They lack a cell wall, are widespread in nature and many are animal, plantand human pathogens. The extensive use of cell cultures in the last fifty years and their frequent contamination with mycoplasmas, together with their possession of the smallest genome of any free-living organism, has drawn enormous attention to these organisms and has revealed considerably more about their biology.
Microbially mediated decomposition of particulate organic carbon (POC) is a central component of the oceanic carbon cycle, controlling the flux of organic carbon from the surface ocean to the deep ...ocean. Yet, the specific microbial taxa responsible for POC decomposition and degradation in the deep ocean are still unknown. To target the active microbial lineages involved in these processes, 13C‐labeled particulate organic matter (POM) was used as a substrate to incubate particle‐attached (PAM) and free‐living microbial (FLM) assemblages from the epi‐ and bathypelagic zones of the New Britain Trench (NBT). By combining DNA stable‐isotope probing and Illumina Miseq high‐throughput sequencing of bacterial 16S rRNA gene, we identified 14 active bacterial taxonomic groups that implicated in the decomposition of 13C‐labeled POM at low and high pressures under the temperature of 15°C. Our results show that both PAM and FLM were able to decompose POC and assimilate the released DOC. However, similar bacterial taxa in both the PAM and FLM assemblages were involved in POC decomposition and DOC degradation, suggesting the decoupling between microbial lifestyles and ecological functions. Microbial decomposition of POC and degradation of DOC were accomplished primarily by particle‐attached bacteria at atmospheric pressure and by free‐living bacteria at high pressures. Overall, the POC degradation rates were higher at atmospheric pressure (0.1 MPa) than at high pressures (20 and 40 MPa) under 15°C. Our results provide direct evidence linking the specific particle‐attached and free‐living bacterial lineages to decomposition and degradation of diatomic detritus at low and high pressures and identified the potential mediators of POC fluxes in the epi‐ and bathypelagic zones.
By combining DNA stable‐isotope probing and Illumina Miseq high‐throughput sequencing, we identified 14 bacterial taxonomic groups actively involved in the decomposition of particulate organic matter (POM) at different pressures. Both particle‐attached and free‐living microorganisms were able to decompose POM and assimilate the released dissolved organic matter, suggesting the decoupling between microbial lifestyles and ecological functions. Our results provide direct evidence linking the specific microbial lineages to decomposition and degradation of POM and identified the potential mediators of POM fluxes in the ocean.
Total DNA (intracellular, iDNA and extracellular, eDNA) from ancient permafrost records the mixed genetic repository of the past and present microbial populations through geological time. Given the ...exceptional preservation of eDNA under perennial frozen conditions, typical metagenomic sequencing of total DNA precludes the discrimination between fossil and living microorganisms in ancient cryogenic environments. DNA repair protocols were combined with high throughput sequencing (HTS) of separate iDNA and eDNA fraction to reconstruct metagenome-assembled genomes (MAGs) from ancient microbial DNA entrapped in Siberian coastal permafrost.
Despite the severe DNA damage in ancient permafrost, the coupling of DNA repair and HTS resulted in a total of 52 MAGs from sediments across a chronosequence (26-120 kyr). These MAGs were compared with those derived from the same samples but without utilizing DNA repair protocols. The MAGs from the youngest stratum showed minimal DNA damage and thus likely originated from viable, active microbial species. Many MAGs from the older and deeper sediment appear related to past aerobic microbial populations that had died upon freezing. MAGs from anaerobic lineages, including Asgard archaea, however exhibited minimal DNA damage and likely represent extant living microorganisms that have become adapted to the cryogenic and anoxic environments. The integration of aspartic acid racemization modeling and metaproteomics further constrained the metabolic status of the living microbial populations. Collectively, combining DNA repair protocols with HTS unveiled the adaptive strategies of microbes to long-term survivability in ancient permafrost.
Our results indicated that coupling of DNA repair protocols with simultaneous sequencing of iDNA and eDNA fractions enabled the assembly of MAGs from past and living microorganisms in ancient permafrost. The genomic reconstruction from the past and extant microbial populations expanded our understanding about the microbial successions and biogeochemical alterations from the past paleoenvironment to the present-day frozen state. Furthermore, we provided genomic insights into long-term survival mechanisms of microorganisms under cryogenic conditions through geological time. The combined strategies in this study can be extrapolated to examine other ancient non-permafrost environments and constrain the search for past and extant extraterrestrial life in permafrost and ice deposits on Mars. Video abstract.
Microbial-mediated utilization of particulate organic matter (POM) during its downward transport from the surface to the deep ocean constitutes a critical component of the global ocean carbon cycle. ...However, it remains unclear as to how high hydrostatic pressure (HHP) and low temperature (LT) with the sinking particles affects community structure and network interactions of the particle-attached microorganisms (PAM) and those free-living microorganisms (FLM) in the surrounding water. In this study, we investigated microbial succession and network interactions in experiments simulating POM sinking in the ocean. Diatom-derived
C- and
C-labeled POM were used to incubate surface water microbial communities from the East China Sea (ECS) under pressure (temperature) of 0.1 (25 °C), 20 (4 °C), and 40 (4 °C) MPa (megapascal). Our results show that the diversity and species richness of the PAM and FLM communities decreased significantly with HHP and LT. Microbial community analysis indicated an increase in the relative abundance of Bacteroidetes at high pressure (40 MPa), mostly at the expense of Gammaproteobacteria, Alphaproteobacteria, and Gracilibacteria at atmospheric pressure. Hydrostatic pressure and temperature affected lifestyle preferences between particle-attached (PA) and free-living (FL) microbes. Ecological network analysis showed that HHP and LT enhanced microbial network interactions and resulted in higher vulnerability to networks of the PAM communities and more resilience of those of the FLM communities. Most interestingly, the PAM communities occupied most of the module hubs of the networks, whereas the FLM communities mainly served as connectors of the modules, suggesting their different ecological roles of the two groups of microbes. These results provided novel insights into how HHP and LT affected microbial community dynamics, ecological networks during POM sinking, and the implications for carbon cycling in the ocean.
This study applies a concept Microbial Fuel Cells (MFCs) in a biological cathodic protection (CP) system. The biological CP uses the microbial properties of living microorganisms which are able to ...produce electrons and suffice the requirement for CP in corrosion prevention system. The electrons produce by the bacteria will be diffuse and transfer to the surface area of graphite which is use as anode. The objective of MFCs for CP is to achieve an optimum value of electro potential produce by bacteria inoculated in MFCs system as preventive measures against corrosion occurred in commonly used carbon steel pipeline. The purpose of the study is to identify the wastewater derived from industry, estuary and dairy farm animal that can give the nearest optimum value of -850 mV for CP. Prior to the objective, three different types of waste is choose as samples in this study which are palm oil mill effluent (POME), estuary water and goat’s feces. Wastewater such as POME and estuary water is stored in a freezer at the temperature below 4oC. Meanwhile goat’s feces is soak in distill water for 24 hours before it is place in a freezer. After the collection of wastewater, a proximity analysis such as pH, conductivity, salinity, COD and TSS is conducted to determine the quality of the wastewater. The 4 liter of wastewater is place in a rig and 40g of sodium acetate as substrate is mix so that it will act as medium for bacteria growth in a single chamber MFCs. The backfilling for the experiment is sand with sand to wastewater is 2L and 4L respectively. The anode (graphite) will undergoes treatment to remove contamination by soaking it in a 100% ethanol for 30 minutes and then soak in 1.0 M HCl for one hour. The electro potential reading is record periodically in hourly basis using electrical multi meter for each source of wastewater and correspondent current density and power density will be determined. In the experiment, three samples is used to represents the population of each type of wastewater in order to have accurate reading and more reliable results during analysis. A statistical analysis is use for the purpose of fulfilling the objective of the study. The result of study shows that wastewater from goat’s feces gives the lowest rate of corrosion which is 1.18 x 10-6 kg/h and followed by estuary water and palm oil mill effluent of 4 x 10-6 kg/h and 7.18 x 10-6 kg/h respectively. It is also found that the wastewater from goat’s feces achieved the highest mean negative potential of - 578.07 mV while standard cathodic protection is -850 mV.
Polystyrene (PS) films are used in packaging and biomedical applications because of their transparency and good environmental properties. The present investigation is centered on the antifungal and ...antibacterial activities involved in the film surface. Subsequently, microbial formations were immobilized on the modified PS films. Living microorganisms such as bacteria and yeast were used. Untreated PS films show very fast rate of growth of bacteria within few hours. The study involves developments of polymer surfaces with bacterial growth and further studies after giving antibacterial treatment such as plasma treatment. Major emphasis has been given to study the effect of various parameters which can affect the performance of the improved material. Films were prepared by two methods: plasma treatment under vacuum and under ongoing He-Ne laser source. The parameters such as (1) surface area by contact angle measurements, (2) quality of material before and after treatment by SEM and FTIR spectra and (3) material characterization by UV-vis spectra were studied. It was observed that plasma treatment of the PS material for different processing time improved the surface properties of PS films.
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