scholarly journals Narrative of a versatile and adept species Pseudomonas putida

2020 ◽  
Vol 69 (3) ◽  
pp. 324-338 ◽  
Author(s):  
Maia Kivisaar

Pseudomonas putida is a fast-growing bacterium found mostly in temperate soil and water habitats. The metabolic versatility of P. putida makes this organism attractive for biotechnological applications such as biodegradation of environmental pollutants and synthesis of added-value chemicals (biocatalysis). This organism has been extensively studied in respect to various stress responses, mechanisms of genetic plasticity and transcriptional regulation of catabolic genes. P. putida is able to colonize the surface of living organisms, but is generally considered to be of low virulence. A number of P. putida strains are able to promote plant growth. The aim of this review is to give historical overview of the discovery of the species P. putida and isolation and characterization of P. putida strains displaying potential for biotechnological applications. This review also discusses some major findings in P. putida research encompassing regulation of catabolic operons, stress-tolerance mechanisms and mechanisms affecting evolvability of bacteria under conditions of environmental stress.

Author(s):  
Laura A. Wolter ◽  
Shota Suenami ◽  
Ryo Miyazaki

The gut of honey bees is characterized by a stable and relatively simple community of bacteria, consisting of seven to ten phylotypes. Two closely related honey bees, Apis mellifera (western honey bee) and Apis cerana (eastern honey bee), show a largely comparable occurrence of those phylotypes, but a distinct set of bacterial species and strains within each bee species. Here, we describe the isolation and characterization of Ac13T, a new species within the rare proteobacterial genus Frischella from A. cerana japonica Fabricius. Description of Ac13T as a new species is supported by low identity of the 16S rRNA gene sequence (97.2 %), of the average nucleotide identity based on orthologous genes (77.5 %) and digital DNA–DNA hybridization relatedness (24.7 %) to the next but far related type strain Frischella perrara PEB0191T, isolated from A. mellifera. Cells of Ac13T are mesophilic and have a mean length of 2–4 µm and a width of 0.5 µm. Optimal growth was achieved in anoxic conditions, whereas growth was not observed in oxic conditions and strongly reduced in microaerophilic environment. Strain Ac13T shares several features with other members of the Orbaceae , such as the major fatty acid profile, the respiratory quinone type and relatively low DNA G+C content, in accordance with its evolutionary relationship. Unlike F. perrara , strain Ac13T is susceptible to a broad range of antibiotics, which could be indicative for an antibiotic-free A. cerana bee keeping. In conclusion, we propose strain Ac13T as a novel species for which we propose the name Frischella japonica sp. nov. with the type strain Ac13T (=NCIMB 15259=JCM 34075).


2021 ◽  
Vol 70 (4) ◽  
Author(s):  
Hyo-Young Oh ◽  
Shivakumar S. Jalde ◽  
In-Young Chung ◽  
Yeon-Ji Yoo ◽  
Hye-Jeong Jang ◽  
...  

Introduction. Antipathogenic or antivirulence strategy is to target a virulence pathway that is dispensable for growth, in the hope to mitigate the selection for drug resistance. Hypothesis/Gap Statment. Peroxide stress responses are one of the conserved virulence pathways in bacterial pathogens and thus good targets for antipathogenic strategy. Aim. This study aims to identify a new chemical compound that targets OxyR, the peroxide sensor required for the full virulence of the opportunistic human pathogen, Pseudomonas aeruginosa . Methodology. Computer-based virtual screening under consideration of the ‘eNTRy’ rules and molecular docking were conducted on the reduced form of the OxyR regulatory domain (RD). Selected hits were validated by their ability to phenocopy the oxyR null mutant and modulate the redox cycle of OxyR. Results. We first isolated three robust chemical hits that inhibit OxyR without affecting prototrophic growth or viability. One (compound 1) of those affected the redox cycle of OxyR in response to H2O2 treatment, in a way to impair its function. Compound 1 displayed selective antibacterial efficacy against P. aeruginosa in Drosophila infection model, without antibacterial activity against Staphylococcus aureus . Conclusion. These results suggest that compound 1 could be an antipathogenic hit inhibiting the P. aeruginosa OxyR. More importantly, our study provides an insight into the computer-based discovery of new-paradigm selective antibacterials to treat Gram-negative bacterial infections presumably with few concerns of drug resistance.


2020 ◽  
Vol 2 (11) ◽  
Author(s):  
Keerthana Ponni Kandasamy ◽  
Radhesh Krishnan Subramanian ◽  
Radhakrishnan Srinivasan ◽  
Sengali Ragunath ◽  
G. Balaji ◽  
...  

Macro-algae are a good source of agar oligosaccharides, which can be obtained through bacterial enzymatic hydrolysis. The agarase enzyme secreted by the micro-organisms cleaves the cell wall of the algae and releases agar oligosaccharides as degradation products with various applications. Agarolytic bacteria were isolated from the marine algae Kappaphycus sp., and Sargassum sp., and studied for their agar-degrading properties. Among the 70 isolates, 2 isolates (A13 and Sg8) showed agarase activity in in vitro assays. The maximum agarolytic index was recorded in the isolate Sg8 (3.75 mm and 4.29 µg ml−1 agarase activity), followed by the isolate A13 (2.53 mm and 2.6 µg ml−1 agarase activity). Optimum agarase production of isolate Sg8 was observed at pH7 and at a temperature of 25 °C in 24–48 h, whereas for isolate A13 the optimum production was at pH7 and at a temperature of 37 °C in 48 h. The identities of the agarolytic isolates (Sg8 and A13) were confirmed based on microscopy, morphological, biochemical and molecular analysis as Shewanella algae [National Center for Biotechnology Information (NCBI) GenBank accession number MK121204.1] and Microbulbifer elongatus [NCBI GenBank accession number MK825484.1], respectively.


Microbiology ◽  
2021 ◽  
Vol 167 (4) ◽  
Author(s):  
Tânia Luz Palma ◽  
Anastasiia Shylova ◽  
Maria Clara Costa

The compound 17α-ethinylestradiol (EE2) is a synthetic oestrogen which is classified as a group 1 carcinogen by the World Health Organization. Together with other endocrine disruptor compounds, EE2 has been included in the surface water Watch List by the European Commission, since it causes severe adverse effects in ecosystems. Thus, it became a high priority to find or improve processes such as biodegradation of EE2 to completely remove this drug from the wastewater treatment plants (WWTPs). The present study aimed at the isolation of bacteria capable of degrading EE2 using environmental samples, namely a sludge from the Faro Northwest WWTP. Four isolates with ability to grow in the presence of 50 mg l−1 EE2 were obtained. The analysis of 16SrRNA gene sequences identified the isolated bacteria as Acinetobacter bouvetii, Acinetobacter kookii, Pantoea agglomerans and Shinella zoogloeoides . The results of biodegradation assays showed that Acinetobacter bouvetii , Acinetobacter kookii , Pantoea agglomerans and Shinella zoogloeoides were able to degrade 47±4 %, 55±3 %, 64±4% and 35±4 %, respectively of 13 mg l−1 EE2 after 168 h at 28 °C. To the best of our knowledge, these bacterial isolates were identified as EE2 degraders for the first time. In a preliminary experiment on the identification of metabolic products resulting from EE2 degradation products such as estrone (E1), γ-lactone compounds, 2-pentanedioic acid and 2-butenedioic acid an intermediate metabolite of the TCA cycle, were detected.


Microbiology ◽  
2020 ◽  
Author(s):  
Rafael Montenegro ◽  
Sofía Vieto ◽  
Daniela Wicki-Emmenegger ◽  
Felipe Vásquez-Castro ◽  
Carolina Coronado-Ruiz ◽  
...  

Tellurium oxyanions are chemical species of great toxicity and their presence in the environment has increased because of mining industries and photovoltaic and electronic waste. Recovery strategies for this metalloid that are based on micro-organisms are of interest, but further studies of the transport systems and enzymes responsible for implementing tellurium transformations are required because many mechanisms remain unknown. Here, we investigated the involvement in tellurite uptake of the putative phosphate transporter PitB (PP1373) in soil bacterium Pseudomonas putida KT2440. For this purpose, through a method based on the CRISPR/Cas9 system, we generated a strain deficient in the pitB gene and characterized its phenotype on exposing it to varied concentrations of tellurite. Growth curves and transmission electronic microscopy experiments for the wild-type and ΔpitB strains showed that both were able to internalize tellurite into the cytoplasm and reduce the oxyanion to black nano-sized and rod-shaped tellurium particles, although the ΔpitB strain showed an increased resistance to the tellurite toxic effects. At a concentration of 100 μM tellurite, where the biomass formation of the wild-type strain decreased by half, we observed a greater ability of ΔpitB to reduce this oxyanion with respect to the wild-type strain (~38 vs ~16 %), which is related to the greater biomass production of ΔpitB and not to a greater consumption of tellurite per cell. The phenotype of the mutant was restored on over-expressing pitB in trans. In summary, our results indicate that PitB is one of several transporters responsible for tellurite uptake in P. putida KT2440.


2022 ◽  
Vol 8 (1) ◽  
Author(s):  
Esther Blanco-Romero ◽  
David Durán ◽  
Daniel Garrido-Sanz ◽  
Rafael Rivilla ◽  
Marta Martín ◽  
...  

Rhizosphere colonization by bacteria involves molecular and cellular mechanisms, such as motility and chemotaxis, biofilm formation, metabolic versatility, or biosynthesis of secondary metabolites, among others. Nonetheless, there is limited knowledge concerning the main regulatory factors that drive the rhizosphere colonization process. Here we show the importance of the AmrZ and FleQ transcription factors for adaption in the plant growth-promoting rhizobacterium (PGPR) and rhizosphere colonization model Pseudomonas ogarae F113. RNA-Seq analyses of P. ogarae F113 grown in liquid cultures either in exponential and stationary growth phase, and rhizosphere conditions, revealed that rhizosphere is a key driver of global changes in gene expression in this bacterium. Regarding the genetic background, this work has revealed that a mutation in fleQ causes considerably more alterations in the gene expression profile of this bacterium than a mutation in amrZ under rhizosphere conditions. The functional analysis has revealed that in P. ogarae F113, the transcription factors AmrZ and FleQ regulate genes involved in diverse bacterial functions. Notably, in the rhizosphere, these transcription factors antagonistically regulate genes related to motility, biofilm formation, nitrogen, sulfur, and amino acid metabolism, transport, signalling, and secretion, especially the type VI secretion systems. These results define the regulon of two important bifunctional transcriptional regulators in pseudomonads during the process of rhizosphere colonization.


Microbiology ◽  
2020 ◽  
Vol 166 (7) ◽  
pp. 641-653
Author(s):  
Pratick Khara ◽  
Saswati Biswas ◽  
Indranil Biswas

Streptococcus mutans is one of the major bacteria of the human oral cavity that is associated with dental caries. The pathogenicity of this bacterium is attributed to its ability to rapidly respond and adapt to the ever-changing conditions of the oral cavity. The major player in this adaptive response is ClpP, an intracellular protease involved in degradation of misfolded proteins during stress responses. S. mutans encodes a single clpP gene with an upstream region uniquely containing multiple tandem repeat sequences (RSs). Here, we explored expression of clpP with respect to various stresses and report some new findings. First, we found that at sub-inhibitory concentration, certain cell-wall damaging antibiotics were able to induce clpP expression. Specifically, third- and fourth-generation cephalosporins that target penicillin-binding protein 3 (PBP3) strongly enhanced the clpP expression. However, induction of clpP was weak when the first-generation cephalosporins with lower affinity to PBP3 were used. Surprisingly, carbapenems, which primarily target PBP2, induced expression of clpP the least. Second, we found that a single RS element was capable of inducing clpP expression as efficiently as with the wild-type seven RS elements. Third, we found that the RS-element-mediated modulation of clpP expression was strain dependent, suggesting that specific host factors might be involved in the transcription. And finally, we observed that ClpP regulates its own expression, as the expression of clpP-gusA was higher in a clpP-deficient mutant. This suggests that ClpP is involved in the degradation of activator(s) involved in its own transcription.


Microbiology ◽  
2020 ◽  
Vol 166 (11) ◽  
pp. 1025-1037 ◽  
Author(s):  
Jannis Kuepper ◽  
Maike Otto ◽  
Jasmin Dickler ◽  
Swantje Behnken ◽  
Jorgen Magnus ◽  
...  

Microbial bioproduction of the aromatic acid anthranilate (ortho-aminobenzoate) has the potential to replace its current, environmentally demanding production process. The host organism employed for such a process needs to fulfil certain demands to achieve industrially relevant product levels. As anthranilate is toxic for microorganisms, the use of particularly robust production hosts can overcome issues from product inhibition. The microorganisms Corynebacterium glutamicum and Pseudomonas putida are known for high tolerance towards a variety of chemicals and could serve as promising platform strains. In this study, the resistance of both wild-type strains towards anthranilate was assessed. To further enhance their native tolerance, adaptive laboratory evolution (ALE) was applied. Sequential batch fermentation processes were developed, adapted to the cultivation demands for C. glutamicum and P. putida, to enable long-term cultivation in the presence of anthranilate. Isolation and analysis of single mutants revealed phenotypes with improved growth behaviour in the presence of anthranilate for both strains. The characterization and improvement of both potential hosts provide an important basis for further process optimization and will aid the establishment of an industrially competitive method for microbial synthesis of anthranilate.


2014 ◽  
Vol 64 (Pt_11) ◽  
pp. 3877-3884 ◽  
Author(s):  
Celine De Maesschalck ◽  
Filip Van Immerseel ◽  
Venessa Eeckhaut ◽  
Siegrid De Baere ◽  
Margo Cnockaert ◽  
...  

Strains LMG 27428T and LMG 27427 were isolated from the caecal content of a chicken and produced butyric, lactic and formic acids as major metabolic end products. The genomic DNA G+C contents of strains LMG 27428T and LMG 27427 were 40.4 and 38.8 mol%. On the basis of 16S rRNA gene sequence similarity, both strains were most closely related to the generically misclassified Streptococcus pleomorphus ATCC 29734T. Strain LMG 27428T could be distinguished from S. pleomorphus ATCC 29734T based on production of more lactic acid and less formic acid in M2GSC medium, a higher DNA G+C content and the absence of activities of acid phosphatase and leucine, arginine, leucyl glycine, pyroglutamic acid, glycine and histidine arylamidases, while strain LMG 27428 was biochemically indistinguishable from S. pleomorphus ATCC 29734T. The novel genus Faecalicoccus gen. nov. within the family Erysipelotrichaceae is proposed to accommodate strains LMG 27428T and LMG 27427. Strain LMG 27428T ( = DSM 26963T) is the type strain of Faecalicoccus acidiformans sp. nov., and strain LMG 27427 ( = DSM 26962) is a strain of Faecalicoccus pleomorphus comb. nov. (type strain LMG 17756T = ATCC 29734T = DSM 20574T). Furthermore, the nearest phylogenetic neighbours of the genus Faecalicoccus are the generically misclassified Eubacterium cylindroides DSM 3983T (94.4 % 16S rRNA gene sequence similarity to strain LMG 27428T) and Eubacterium biforme DSM 3989T (92.7 % 16S rRNA gene sequence similarity to strain LMG 27428T). We present genotypic and phenotypic data that allow the differentiation of each of these taxa and propose to reclassify these generically misnamed species of the genus Eubacterium formally as Faecalitalea cylindroides gen. nov., comb. nov. and Holdemanella biformis gen. nov., comb. nov., respectively. The type strain of Faecalitalea cylindroides is DSM 3983T = ATCC 27803T = JCM 10261T and that of Holdemanella biformis is DSM 3989T = ATCC 27806T = CCUG 28091T.


2015 ◽  
Vol 65 (Pt_6) ◽  
pp. 1819-1824 ◽  
Author(s):  
Sooyeon Park ◽  
Ji-Min Park ◽  
Chul-Hyung Kang ◽  
Song-Gun Kim ◽  
Jung-Hoon Yoon

A Gram-stain-negative, non-motile, aerobic and pleomorphic bacterium, designated BS-W13T, was isolated from a tidal flat on the South Sea, South Korea, and its taxonomic position was investigated using a polyphasic approach. Strain BS-W13T grew optimally at 25 °C, at pH 7.0–8.0 and in the presence of 1.0–2.0 % (w/v) NaCl. Neighbour-joining and maximum-parsimony phylogenetic trees based on 16S rRNA gene sequences showed that strain BS-W13T clustered with the type strain of Seohaeicola saemankumensis , showing the highest sequence similarity (95.96 %) to this strain. Strain BS-W13T exhibited 16S rRNA gene sequence similarity values of 95.95, 95.91, 95.72 and 95.68 % to the type strains of Sulfitobacter donghicola , Sulfitobacter porphyrae , Sulfitobacter mediterraneus and Roseobacter litoralis , respectively. Strain BS-W13T contained Q-10 as the predominant ubiquinone and C18 : 1ω7c as the major fatty acid. The polar lipid profile of strain BS-W13T, containing phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, one unidentified aminolipid and one unidentified lipid as major components, was distinguishable from those of some phylogenetically related taxa. The DNA G+C content of strain BS-W13T was 58.1 mol%. The phylogenetic data and differential chemotaxonomic and other phenotypic properties revealed that strain BS-W13T constitutes a novel genus and species within family Rhodobacteraceae of the class Alphaproteobacteria , for which the name Pseudoseohaeicola caenipelagi gen. nov., sp. nov. is proposed. The type strain is BS-W13T ( = KCTC 42349T = CECT 8724T).


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