The actinomycete Kitasatospora sp. SeTe27, subjected to adaptive laboratory evolution (ALE) in the presence of selenite, varies its cellular morphology, redox stability, and tolerance to the toxic oxyanion.

The effects of oxyanions selenite (SeO) in soils are of high concern in ecotoxicology and microbiology as they can react with mineral particles and microorganisms. This study investigated the evolution of the actinomycete Kitasatospora sp. SeTe27 in response to selenite.

Insights into the Synergistic Antibacterial Activity of Silver Nitrate with Potassium Tellurite against .

The constant, ever-increasing antibiotic resistance crisis leads to the announcement of "urgent, novel antibiotics needed" by the World Health Organization. Our previous works showed a promising synergistic antibacterial activity of silver nitrate with potassium tellurite out of thousands of other metal/metalloid-based antibacterial combinations. The silver-tellurite combined treatment not only is more effective than common antibiotics but also prevents bacterial recovery, decreases the risk of future resistance chance, and decreases the effective concentrations.

Tolerance, Adaptation, and Cell Response Elicited by sp. Facing Tellurite Toxicity: A Biological and Physical-Chemical Characterization.

The intense use of tellurium (Te) in industrial applications, along with the improper disposal of Te-derivatives, is causing their accumulation in the environment, where oxyanion tellurite (TeO) is the most soluble, bioavailable, and toxic Te-species. On the other hand, tellurium is a rare metalloid element whose natural supply will end shortly with possible economic and technological effects. Thus, Te-containing waste represents the source from which Te should be recycled and recovered.

Tellurite and Selenite: how can these two oxyanions be chemically different yet so similar in the way they are transformed to their metal forms by bacteria?

This opinion review explores the microbiology of tellurite, TeO and selenite, SeO oxyanions, two similar Group 16 chalcogen elements, but with slightly different physicochemical properties that lead to intriguing biological differences. Selenium, Se, is a required trace element compared to tellurium, Te, which is not. Here, the challenges around understanding the uptake transport mechanisms of these anions, as reflected in the model organisms used by different groups, are described.

Molecular characterization of microbial communities in a peat-rich aquifer system contaminated with chlorinated aliphatic compounds.

In an aquifer-aquitard system in the subsoil of the city of Ferrara (Emilia-Romagna region, northern Italy) highly contaminated with chlorinated aliphatic toxic organics such as trichloroethylene (TCE) and tetrachloroethylene (PCE), a strong microbial-dependent dechlorination activity takes place during migration of contaminants through shallow organic-rich layers with peat intercalations. The in situ microbial degradation of chlorinated ethenes, formerly inferred by the utilization of contaminant concentration profiles and Compound-Specific Isotope Analysis (CSIA), was here assessed using Illumina sequencing of V4 hypervariable region of 16S rRNA gene and by clone library analysis of dehalogenase metabolic genes. Taxon-specific investigation of the microbial communities catalyzing the chlorination process revealed the presence of not only dehalogenating genera such as Dehalococcoides and Dehalobacter but also of numerous other groups of non-dehalogenating bacteria and archaea thriving on diverse metabolisms such as hydrolysis and fermentation of complex organic matter, acidogenesis, acetogenesis, and methanogenesis, which can indirectly support the reductive dechlorination process.

Processing of Metals and Metalloids by : Cell Resistance Mechanisms and Synthesis of Metal(loid)-Based Nanostructures.

Metal(loid)s have a dual biological role as micronutrients and stress agents. A few geochemical and natural processes can cause their release in the environment, although most metal-contaminated sites derive from anthropogenic activities. Actinobacteria include high GC bacteria that inhabit a wide range of terrestrial and aquatic ecological niches, where they play essential roles in recycling or transforming organic and inorganic substances.

Biotechnology of Rhodococcus for the production of valuable compounds.

Bacteria belonging to Rhodococcus genus represent ideal candidates for microbial biotechnology applications because of their metabolic versatility, ability to degrade a wide range of organic compounds, and resistance to various stress conditions, such as metal toxicity, desiccation, and high concentration of organic solvents. Rhodococcus spp. strains have also peculiar biosynthetic activities that contribute to their strong persistence in harsh and contaminated environments and provide them a competitive advantage over other microorganisms.

Structural and electrochemical characterization of lawsone-dependent production of tellurium-metal nanoprecipitates by photosynthetic cells of Rhodobacter capsulatus.

Cells of the facultative photosynthetic bacterium Rhodobacter capsulatus exploit the simultaneous presence in the cultural medium of the toxic oxyanion tellurite (TeO) and the redox mediator lawsone (2-hydroxy-1,4-naphthoquinone) by reducing tellurite to metal Te nanoprecipitates (TeNPs) outside the cells. Here we have studied the mechanism by which lawsone interacts with metabolically active cells and analysed both structure and composition of the TeNPs collected from the growth medium of phototrophycally grown R. capsulatus.

Identification of Resistance Genes and Response to Arsenic in BCP1.

Arsenic (As) ranks among the priority metal(loid)s that are of public health concern. In the environment, arsenic is present in different forms, organic or inorganic, featured by various toxicity levels. Bacteria have developed different strategies to deal with this toxicity involving different resistance genetic determinants.

Microbial diversity and biosignatures of amorphous silica deposits in orthoquartzite caves.

Chemical mobility of crystalline and amorphous SiO plays a fundamental role in several geochemical and biological processes, with silicate minerals being the most abundant components of the Earth's crust. Although the oldest evidences of life on Earth are fossilized in microcrystalline silica deposits, little is known about the functional role that bacteria can exert on silica mobility at non-thermal and neutral pH conditions. Here, a microbial influence on silica mobilization event occurring in the Earth's largest orthoquartzite cave is described.

Some facts about the respiratory enzymes of Pseudomonas pseudoalcaligenes KF707 recently renamed as Pseudomonas furukawaii sp. nov., type strain KF707.

Kimura and co-workers (Kimura N et al. Int J Syst Evol Microbiol 2018;68:1429-1435) recently proposed renaming the obligate aerobe Pseudomonas pseudoalcaligenes KF707 as Pseudomonas furukawiisp. nov.

Aerobic Growth of BCP1 Using Selected Naphthenic Acids as the Sole Carbon and Energy Sources.

Naphthenic acids (NAs) are an important group of toxic organic compounds naturally occurring in hydrocarbon deposits. This work shows that BCP1 cells not only utilize a mixture of eight different NAs (8XNAs) for growth but they are also capable of marked degradation of two model NAs, cyclohexanecarboxylic acid (CHCA) and cyclopentanecarboxylic acid (CPCA) when supplied at concentrations from 50 to 500 mgL. The growth curves of BCP1 on 8XNAs, CHCA, and CPCA showed an initial lag phase not present in growth on glucose, which presumably was related to the toxic effects of NAs on the cell membrane permeability.

Assembly, growth and conductive properties of tellurium nanorods produced by Rhodococcus aetherivorans BCP1.

Tellurite (TeO) is a hazardous and toxic oxyanion for living organisms. However, several microorganisms can bioconvert TeO into the less toxic form of elemental tellurium (Te). Here, Rhodococcus aetherivorans BCP1 resting (non-growing) cells showed the proficiency to produce tellurium-based nanoparticles (NPs) and nanorods (NRs) through the bioconversion of TeO, depending on the oxyanion initial concentration and time of cellular incubation.

Pseudomonas pseudoalcaligenes KF707 grown with biphenyl expresses a cytochrome caa oxidase that uses cytochrome c as electron donor.

Combining peroxidase activity-based heme staining (TMBZ/SDS/PAGE) with mass spectrometry analyses (Nano LC-MS/MS) of protein extracts from wild-type and appropriate mutants, we provide evidence that the polychlorinated biphenyl degrader Pseudomonas pseudoalcaligenes KF707 primarily expresses a caa -type cytochrome c oxidase (caa -Cox) using cytochrome (cyt) c as an electron donor in cells grown with biphenyl versus glucose as the sole carbon source. Homology modeling of KF707 caa -Cox using the three-dimensional structure of that from Thermus thermophilus highlights multiple similarities and differences between the proton channels in subunit I of the aa - and caa -Cox of Paracoccus and Thermus spp., respectively.

Biosynthesis of selenium-nanoparticles and -nanorods as a product of selenite bioconversion by the aerobic bacterium Rhodococcus aetherivorans BCP1.

The wide anthropogenic use of selenium compounds represents the major source of selenium pollution worldwide, causing environmental issues and health concerns. Microbe-based strategies for metal removal/recovery have received increasing interest thanks to the association of the microbial ability to detoxify toxic metal/metalloid polluted environments with the production of nanomaterials. This study investigates the tolerance and the bioconversion of selenite (SeO) by the aerobically grown Actinomycete Rhodococcus aetherivorans BCP1 in association with its ability to produce selenium nanoparticles and nanorods (SeNPs and SeNRs).

Biphenyl Modulates the Expression and Function of Respiratory Oxidases in the Polychlorinated-Biphenyls Degrader KF707.

KF707 is a soil bacterium which is known for its capacity to aerobically degrade harmful organic compounds such as polychlorinated biphenyls (PCBs) using biphenyl as co-metabolite. Here we provide the first genetic and functional analysis of the KF707 respiratory terminal oxidases in cells grown with two different carbon sources: glucose and biphenyl. We identified five terminal oxidases in KF707: two type oxidases (Caa and Ccaa), two type oxidases (Cbb1 and Cbb2), and one type cyanide-insensitive quinol oxidase (CIO).

Rhodococcus aetherivorans BCP1 as cell factory for the production of intracellular tellurium nanorods under aerobic conditions.

Background: Tellurite (TeO) is recognized as a toxic oxyanion to living organisms. However, mainly anaerobic or facultative-anaerobic microorganisms are able to tolerate and convert TeO into the less toxic and available form of elemental Tellurium (Te), producing Te-deposits or Te-nanostructures. The use of TeO-reducing bacteria can lead to the decontamination of polluted environments and the development of "green-synthesis" methods for the production of nanomaterials.

Reprint of "Extracellular production of tellurium nanoparticles by the photosynthetic bacterium Rhodobacter capsulatus".

The toxic oxyanion tellurite (TeO) is acquired by cells of Rhodobacter capsulatus grown anaerobically in the light, via acetate permease ActP2 and then reduced to Te in the cytoplasm as needle-like black precipitates. Interestingly, photosynthetic cultures of R. capsulatus can also generate Te nanoprecipitates (TeNPs) outside the cells upon addition of the redox mediator lawsone (2-hydroxy-1,4-naphtoquinone).

On the role of a specific insert in acetate permeases (ActP) for tellurite uptake in bacteria: Functional and structural studies.

The oxyanion tellurite (TeO) is extremely toxic to bacterial cells. In Rhodobacter capsulatus, tellurite enters the cytosol by means of the high uptake-rate acetate permease RcActP2, encoded by one of the three actP genes present in this species (actP1, actP2 and actP3). Conversely, in Escherichia coli a low rate influx of the oxyanion is measured, which depends mainly on the phosphate transporter EcPitA, even though E.

Diversity of Methane-Oxidizing Bacteria in Soils from "Hot Lands of Medolla" (Italy) Featured by Anomalous High-Temperatures and Biogenic CO Emission.

"Terre Calde di Medolla" (TCM) (literally, "Hot Lands of Medolla") refers to a farming area in Italy with anomalously high temperatures and diffuse emissions of biogenic CO, which has been linked to CH oxidation processes from a depth of 0.7 m to the surface. We herein assessed the composition of the total bacterial community and diversity of methane-oxidizing bacteria (MOB) in soil samples collected at a depth at which the peak temperature was detected (0.

Phenotype microarray analysis may unravel genetic determinants of the stress response by Rhodococcus aetherivorans BCP1 and Rhodococcus opacus R7.

In the present study, the response of Rhodococcus aetherivorans BCP1 and Rhodococcus opacus R7 to various stress conditions and several antimicrobials was examined by PM in relation with genetic determinants, as revealed by annotation analysis of the two genomes. Comparison between metabolic activities and genetic features of BCP1 and R7 provided new insight into the environmental persistence of these two members of the genus Rhodococcus.