scholarly journals Mannosylglycerate and Di-myo-Inositol Phosphate Have Interchangeable Roles during Adaptation of Pyrococcus furiosus to Heat Stress

2014 ◽  
Vol 80 (14) ◽  
pp. 4226-4233 ◽  
Author(s):  
Ana M. Esteves ◽  
Sanjeev K. Chandrayan ◽  
Patrick M. McTernan ◽  
Nuno Borges ◽  
Michael W. W. Adams ◽  
...  
Keyword(s):  
Heat Stress ◽  
Pyrococcus Furiosus ◽  
Inositol Phosphate ◽  
Compatible Solutes ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Cell Protection ◽  
Content Type ◽  
Molecular Events ◽  
Supraoptimal Temperatures

ABSTRACTMarine hyperthermophiles accumulate small organic compounds, known as compatible solutes, in response to supraoptimal temperatures or salinities.Pyrococcus furiosusis a hyperthermophilic archaeon that grows optimally at temperatures near 100°C. This organism accumulates mannosylglycerate (MG) and di-myo-inositol phosphate (DIP) in response to osmotic and heat stress, respectively. It has been assumed that MG and DIP are involved in cell protection; however, firm evidence for the roles of these solutes in stress adaptation is still missing, largely due to the lack of genetic tools to produce suitable mutants of hyperthermophiles. Recently, such tools were developed forP. furiosus, making this organism an ideal target for that purpose. In this work, genes coding for the synthases in the biosynthetic pathways of MG and DIP were deleted by double-crossover homologous recombination. The growth profiles and solute patterns of the two mutants and the parent strain were investigated under optimal growth conditions and also at supraoptimal temperatures and NaCl concentrations. DIP was a suitable replacement for MG during heat stress, but substitution of MG for DIP and aspartate led to less efficient growth under conditions of osmotic stress. The results suggest that the cascade of molecular events leading to MG synthesis is tuned for osmotic adjustment, while the machinery for induction of DIP synthesis responds to either stress agent. MG protects cells against heat as effectively as DIP, despite the finding that the amount of DIP consistently increases in response to heat stress in the nine (hyper)thermophiles examined thus far.

scholarly journals Carboxydocella manganica sp. nov., a thermophilic, dissimilatory Mn(IV)- and Fe(III)-reducing bacterium from a Kamchatka hot spring

2012 ◽  
Vol 62 (Pt_4) ◽  
pp. 890-894 ◽  
Author(s):  
G. B. Slobodkina ◽  
A. N. Panteleeva ◽  
T. G. Sokolova ◽  
E. A. Bonch-Osmolovskaya ◽  
A. I. Slobodkin
Keyword(s):  
Hot Spring ◽  
Phylogenetic Analyses ◽  
Optimal Growth ◽  
Kamchatka Peninsula ◽  
Growth Conditions ◽  
Rrna Gene ◽  
Content Type ◽  
Link Type ◽  
Physiological Properties ◽  
Bacterium Strain

A thermophilic, anaerobic, dissimilatory Mn(IV)- and Fe(III)-reducing bacterium (strain SLM 61T) was isolated from a terrestrial hot spring on the Kamchatka peninsula. The cells were straight rods, 0.5–0.6 µm in diameter and 1.0–6.0 µm long, and exhibited tumbling motility by means of peritrichous flagellation. The strain grew at 26–70 °C, with an optimum at 58–60 °C, and at pH 5.5–8.0, with an optimum at pH 6.5. Growth of SLM 61T was observed at 0–2.0 % (w/v) NaCl, with an optimum at 0.5 % (w/v). The generation time under optimal growth conditions was 40 min. Strain SLM 61T grew and reduced Mn(IV), Fe(III) or nitrate with a number of organic acids and complex proteinaceous compounds as electron donors. It was capable of chemolithoautotrophic growth using molecular hydrogen as an electron donor, Fe(III) but not Mn(IV) or nitrate as an electron acceptor and CO2 as a carbon source. It also was able to ferment pyruvate, yeast extract, glucose, fructose, sucrose and maltose. The G+C content of DNA of strain SLM 61T was 50.9 mol%. 16S rRNA gene sequence analysis revealed that the closest relative of the isolated organism was Carboxydocella thermautotrophica 41T (96.9 % similarity). On the basis of its physiological properties and phylogenetic analyses, the isolate is considered to represent a novel species, for which the name Carboxydocella manganica sp. nov. is proposed. The type strain is SLM 61T ( = DSM 23132T  = VKM B-2609T). C. manganica is the first described representative of the genus Carboxydocella that possesses the ability to reduce metals and does not utilize CO.

scholarly journals The Stringent Stress Response Controls Proteases and Global Regulators under Optimal Growth Conditions in Pseudomonas aeruginosa

mSystems ◽  
2020 ◽  
Vol 5 (4) ◽  
Author(s):  
Daniel Pletzer ◽  
Travis M. Blimkie ◽  
Heidi Wolfmeier ◽  
Yicong Li ◽  
Arjun Baghela ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Stress Response ◽  
Stringent Response ◽  
Optimal Growth ◽  
Transcriptional Regulators ◽  
Growth Conditions ◽  
Rna Seq ◽  
Signaling Molecule ◽  
Content Type ◽  
Response Mutant

ABSTRACT The bacterial stringent stress response, mediated by the signaling molecule guanosine tetraphosphate, ppGpp, has recently gained attention as being important during normal cellular growth and as a potential new therapeutic target, which warrants detailed mechanistic understanding. Here, we used intracellular protein tracking in Pseudomonas aeruginosa PAO1, which indicated that RelA was bound to the ribosome, while SpoT localized at the cell poles. Transcriptome sequencing (RNA-Seq) was used to investigate the transcriptome of a ppGpp-deficient strain under nonstressful, nutrient-rich broth conditions where the mutant grew at the same rate as the parent strain. In the exponential growth phase, the lack of ppGpp led to >1,600 transcriptional changes (fold change cutoff of ±1.5), providing further novel insights into the normal physiological role of ppGpp. The stringent response was linked to gene expression of various proteases and secretion systems, including aprA, PA0277, impA, and clpP2. The previously observed reduction in cytotoxicity toward red blood cells in a stringent response mutant appeared to be due to aprA. Investigation of an aprA mutant in a murine skin infection model showed increased survival rates of mice infected with the aprA mutant, consistent with previous observations that stringent response mutants have reduced virulence. In addition, the overexpression of relA, but not induction of ppGpp with serine hydroxamate, dysregulated global transcriptional regulators as well as >30% of the regulatory networks controlled by AlgR, OxyR, LasR, and AmrZ. Together, these data expand our knowledge about ppGpp and its regulatory network and role in environmental adaptation. It also confirms its important role throughout the normal growth cycle of bacteria. IMPORTANCE Microorganisms need to adapt rapidly to survive harsh environmental changes. Here, we showed the broad influence of the highly studied bacterial stringent stress response under nonstressful conditions that indicate its general physiological importance and might reflect the readiness of bacteria to respond to and activate acute stress responses. Using RNA-Seq to investigate the transcriptional network of Pseudomonas aeruginosa cells revealed that >30% of all genes changed expression in a stringent response mutant under optimal growth conditions. This included genes regulated by global transcriptional regulators and novel downstream effectors. Our results help to understand the importance of this stress regulator in bacterial lifestyle under relatively unstressed conditions. As such, it draws attention to the consequences of targeting this ubiquitous bacterial signaling molecule.

scholarly journals Halophilic microorganisms in deteriorated historic buildings: insights into their characteristics.

2016 ◽  
Vol 63 (2) ◽  
Author(s):  
Justyna Adamiak ◽  
Anna Otlewska ◽  
Beata Gutarowska ◽  
Anna Pietrzak
Keyword(s):  
Compatible Solutes ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Biochemical Properties ◽  
Salt Crystallization ◽  
Historic Buildings ◽  
Material Loss ◽  
Halophilic Microorganisms ◽  
Salt Hydrates ◽  
Temperature Ranges

Historic buildings are constantly being exposed to numerous climatic changes such as damp and rainwater. Water migration into and out of the material's pores can lead to salt precipitation and the so-called efflorescence. The structure of the material may be seriously threatened by salt crystallization. A huge pressure is produced when salt hydrates occupy larger spaces, which leads at the end to cracking, detachment and material loss. Halophilic microorganisms have the ability to adapt to high salinity because of the mechanisms of inorganic salt (KCl or NaCl) accumulation in their cells at concentrations isotonic to the environment, or compatible solutes uptake or synthesis. In this study, we focused our attention on the determination of optimal growth conditions of halophilic microorganisms isolated from historical buildings in terms of salinity, pH and temperature ranges, as well as biochemical properties and antagonistic abilities. Halophilic microorganisms studied in this paper could be categorized as a halotolerant group, as they grow in the absence of NaCl, as well as tolerate higher salt concentrations (Staphylococcus succinus, Virgibacillus halodenitrificans). Halophilic microorganisms have been also observed (Halobacillus styriensis, H. hunanensis, H. naozhouensis, H. litoralis, Marinococcus halophilus and yeast Sterigmatomyces halophilus). With respect to their physiological characteristics, cultivation at a temperature of 25-30°C, pH 6-7, NaCl concentration for halotolerant and halophilic microorganisms, 0-10% and 15-30%, respectively, provides the most convenient conditions. Halophiles described in this study displayed lipolytic, glycolytic and proteolytic activities. Staphylococcus succinus and Marinococcus halophilus showed strong antagonistic potential towards bacteria from the Bacillus genus, while Halobacillus litoralis displayed an inhibiting ability against other halophiles.

scholarly journals Optimization of Methanotrophic Growth and Production of Poly(3-Hydroxybutyrate) in a High-Throughput Microbioreactor System

2015 ◽  
Vol 81 (14) ◽  
pp. 4767-4773 ◽  
Author(s):  
Eric R. Sundstrom ◽  
Craig S. Criddle
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Medium Optimization ◽  
Nile Red ◽  
Bacterial Biomass ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Culture Conditions ◽  
High Mass ◽  
Content Type

ABSTRACTProduction of poly(3-hydroxybutyrate) (P3HB) from methane has economic and environmental advantages over production by agricultural feedstock. Identification of high-productivity strains and optimal growth conditions is critical to efficient conversion of methane to polymer. Current culture conditions, including serum bottles, shake flasks, and agar plates, are labor-intensive and therefore insufficient for systematic screening and isolation. Gas chromatography, the standard method for analysis of P3HB content in bacterial biomass, is also incompatible with high-throughput screening. Growth in aerated microtiter plates coupled with a 96-well Nile red flow-cytometric assay creates an integrated microbioreactor system for high-throughput growth and analysis of P3HB-producing methanotrophic cultures, eliminating the need for individual manipulation of experimental replicates. This system was tested in practice to conduct medium optimization for P3HB production in pure cultures ofMethylocystis parvusOBBP. Optimization gave insight into unexpected interactions: for example, low calcium concentrations significantly enhanced P3HB production under nitrogen-limited conditions. Optimization of calcium and copper concentrations in the growth medium increased final P3HB content from 18.1% to 49.4% and P3HB concentration from 0.69 g/liter to 3.43 g/liter while reducing doubling time from 10.6 h to 8.6 h. The ability to culture and analyze thousands of replicates with high mass transfer in completely mixed culture promises to streamline medium optimization and allow the detection and isolation of highly productive strains. Applications for this system are numerous, encompassing analysis of biofuels and other lipid inclusions, as well as analysis of heterotrophic and photosynthetic systems.

scholarly journals Glycerol Phosphate Cytidylyltransferase Stereospecificity Is Key to Understanding the Distinct Stereochemical Compositions of Glycerophosphoinositol in Bacteria and Archaea

2016 ◽  
Vol 83 (1) ◽  
Author(s):  
Marta V. Rodrigues ◽  
Nuno Borges ◽  
Helena Santos
Keyword(s):  
Thermal Protection ◽  
Inositol Phosphate ◽  
Compatible Solutes ◽  
Model Organisms ◽  
Synthetase Activity ◽  
Glycerol Phosphate ◽  
Molecular Configuration ◽  
Biochemical Basis ◽  
Content Type ◽  
Inositol 1

ABSTRACT Glycerophosphoinositol (GPI) is a compatible solute present in a few hyperthermophiles. Interestingly, different GPI stereoisomers accumulate in Bacteria and Archaea, and the basis for this domain-dependent specificity was investigated herein. The archaeon Archaeoglobus fulgidus and the bacterium Aquifex aeolicus were used as model organisms. The synthesis of GPI involves glycerol phosphate cytidylyltransferase (GCT), which catalyzes the production of CDP-glycerol from CTP and glycerol phosphate, and di-myo-inositol phosphate-phosphate synthase (DIPPS), catalyzing the formation of phosphorylated GPI from CDP-glycerol and l-myo-inositol 1-phosphate. DIPPS of A. fulgidus recognized the two CDP-glycerol stereoisomers similarly. This feature and the ability of 31P nuclear magnetic resonance (NMR) to distinguish the GPI diastereomers provided a means to study the stereospecificity of GCTs. The AF1418 gene and genes aq_185 and aq_1368 are annotated as putative GCT genes in the genomes of A. fulgidus and Aq. aeolicus, respectively. The functions of these genes were determined by assaying the activity of the respective recombinant proteins: AQ1368 and AQ185 are GCTs, while AF1418 has flavin adenine dinucleotide (FAD) synthetase activity. AQ185 is absolutely specific for sn-glycerol 3-phosphate, while AQ1368 recognizes the two enantiomers but has a 2:1 preference for sn-glycerol 3-phosphate. In contrast, the partially purified A. fulgidus GCT uses sn-glycerol 1-phosphate preferentially (4:1). Significantly, the predominant GPI stereoforms found in the bacterium and the archaeon reflect the distinct stereospecificities of the respective GCTs: i.e., A. fulgidus accumulates predominantly sn-glycero-1-phospho-3-l-myo-inositol, while Aq. aeolicus accumulates sn-glycero-3-phospho-3-l-myo-inositol. IMPORTANCE Compatible solutes of hyperthermophiles show high efficacy in thermal protection of proteins in comparison with solutes typical of mesophiles; therefore, they are potentially useful in several biotechnological applications. Glycerophosphoinositol (GPI) is synthesized from CDP-glycerol and l-myo-inositol 1-phosphate in a few hyperthermophiles. In this study, the molecular configuration of the GPI stereoisomers accumulated by members of the Bacteria and Archaea was established. The stereospecificity of glycerol phosphate cytidylyltransferase (GCT), the enzyme catalyzing the synthesis of CDP-glycerol, is crucial to the stereochemistry of GPI. However, the stereospecific properties of GCTs have not been investigated thus far. We devised a method to characterize GCT stereospecificity which does not require sn-glycerol 1-phosphate, a commercially unavailable substrate. This led us to understand the biochemical basis for the distinct GPI stereoisomer composition observed in archaea and bacteria.

scholarly journals Thermococcus kodakarensis Mutants Deficient in Di-myo-Inositol Phosphate Use Aspartate To Cope with Heat Stress

2009 ◽  
Vol 192 (1) ◽  
pp. 191-197 ◽  
Author(s):  
Nuno Borges ◽  
Rie Matsumi ◽  
Tadayuki Imanaka ◽  
Haruyuki Atomi ◽  
Helena Santos
Keyword(s):  
Heat Stress ◽  
Parental Strain ◽  
Inositol Phosphate ◽  
Growth Parameters ◽  
Compatible Solutes ◽  
Similar Efficacy ◽  
Marine Microorganisms ◽  
Gene Encoding ◽  
Key Enzyme ◽  
Thermophilic Organisms

ABSTRACT Many of the marine microorganisms which are adapted to grow at temperatures above 80°C accumulate di-myo-inositol phosphate (DIP) in response to heat stress. This led to the hypothesis that the solute plays a role in thermoprotection, but there is a lack of definitive experimental evidence. Mutant strains of Thermococcus kodakar ensis (formerly Thermococcus kodakaraensis), manipulated in their ability to synthesize DIP, were constructed and used to investigate the involvement of DIP in thermoadaptation of this archaeon. The solute pool of the parental strain comprised DIP, aspartate, and α-glutamate. Under heat stress the level of DIP increased 20-fold compared to optimal conditions, whereas the pool of aspartate increased 4.3-fold in response to osmotic stress. Deleting the gene encoding the key enzyme in DIP synthesis, CTP:inositol-1-phosphate cytidylyltransferase/CDP-inositol:inositol-1-phosphate transferase, abolished DIP synthesis. Conversely, overexpression of the same gene resulted in a mutant with restored ability to synthesize DIP. Despite the absence of DIP in the deletion mutant, this strain exhibited growth parameters similar to those of the parental strain, both at optimal (85°C) and supraoptimal (93.7°C) temperatures for growth. Analysis of the respective solute pools showed that DIP was replaced by aspartate. We conclude that DIP is part of the strategy used by T. kodakarensis to cope with heat stress, and aspartate can be used as an alternative solute of similar efficacy. This is the first study using mutants to demonstrate the involvement of compatible solutes in the thermoadaptation of (hyper)thermophilic organisms.

scholarly journals Duration of Heat Stress Effect on Invasiveness ofL. monocytogenesStrains

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Ewa Wałecka-Zacharska ◽  
Renata Gmyrek ◽  
Krzysztof Skowron ◽  
Katarzyna Kosek-Paszkowska ◽  
Jacek Bania
Keyword(s):  
Heat Stress ◽  
Stress Response ◽  
Heat Shock ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Stress Effect ◽  
Heat Shock Stress ◽  
Heat Treated ◽  
Strain Dependent ◽  
Invasion Capacity

During food production and food conservation, as well as the passage through the human gastrointestinal (GI) tract,L. monocytogenesis exposed to many adverse conditions which may elicit a stress response. As a result the pathogen may become more resistant to other unpropitious factors and may change its virulence. It has been shown that low and high temperature, salt, low pH, and high pressure affect the invasion capacity ofL. monocytogenes. However, there is a scarcity of data on the duration of the stress effect on bacterial biology, including invasiveness. The aim of this work was to determine the period during whichL. monocytogenesinvasiveness remains altered under optimal conditions following exposure of bacteria to mild heat shock stress. TenL. monocytogenesstrains were exposed to heat shock at 54°C for 20 minutes. Then both heat-treated and nontreated control bacteria were incubated under optimal growth conditions, 37°C, for up to 72 hours and the invasion capacity was tested. Additionally, the expression of virulence and stress response genes was investigated in 2 strains. We found that heat stress exposure significantly decreases the invasiveness of all tested strains. However, during incubation at 37°C the invasion capacity of heat-treated strains recovered to the level of nontreated controls. The observed effect was strain-dependent and lasted from less than 24 hours to 72 hours. The invasiveness of 6 out of the 10 nontreated strains decreased during incubation at 37°C. The expression ofinlABcorrelated with the increase of invasiveness but the decrease of invasiveness did not correlate with changes of the level of these transcripts.Conclusions. The effect of heat stress onL. monocytogenesinvasiveness is strain-dependent and was transient, lasting up to 72 hours.

scholarly journals Deciphering the Function of New Gonococcal Vaccine Antigens Using Phenotypic Microarrays

2017 ◽  
Vol 199 (17) ◽  
Author(s):  
Benjamin I. Baarda ◽  
Sarah Emerson ◽  
Philip J. Proteau ◽  
Aleksandra E. Sikora
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Cell Envelope ◽  
Membrane Integrity ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Phenotype Microarray ◽  
Negative Effects ◽  
Content Type ◽  
Vaccine Candidates ◽  
Phenotype Microarrays

ABSTRACTThe function and extracellular location of cell envelope proteins make them attractive candidates for developing vaccines against bacterial diseases, including challenging drug-resistant pathogens, such asNeisseria gonorrhoeae. A proteomics-driven reverse vaccinology approach has delivered multiple gonorrhea vaccine candidates; however, the biological functions of many of them remain to be elucidated. Herein, the functions of six gonorrhea vaccine candidates—NGO2121, NGO1985, NGO2054, NGO2111, NGO1205, and NGO1344—in cell envelope homeostasis were probed using phenotype microarrays under 1,056 conditions and a ΔbamEmutant (Δngo1780) as a reference of perturbed outer membrane integrity. Optimal growth conditions for anN. gonorrhoeaephenotype microarray assay in defined liquid medium were developed, which can be useful in other applications, including rapid and thorough antimicrobial susceptibility assessment. Our studies revealed 91 conditions having uniquely positive or negative effects on one of the examined mutants. A cluster analysis of 37 and 57 commonly beneficial and detrimental compounds, respectively, revealed three separate phenotype groups: NGO2121 and NGO1985; NGO1344 and BamE; and the trio of NGO1205, NGO2111, and NGO2054, with the last protein forming an independent branch of this cluster. Similar phenotypes were associated with loss of these vaccine candidates in the highly antibiotic-resistant WHO X strain. Based on their extensive sensitivity phenomes, NGO1985 and NGO2121 appear to be the most promising vaccine candidates. This study establishes the principle that phenotype microarrays can be successfully applied to a fastidious bacterial organism, such asN. gonorrhoeae.IMPORTANCEInnovative approaches are required to develop vaccines against prevalent and neglected sexually transmitted infections, such as gonorrhea. Herein, we have utilized phenotype microarrays in the first such investigation intoNeisseria gonorrhoeaeto probe the function of proteome-derived vaccine candidates in cell envelope homeostasis. Information gained from this screening can feed the vaccine candidate decision tree by providing insights into the roles these proteins play in membrane permeability, integrity, and overallN. gonorrhoeaephysiology. The optimized screening protocol can be applied in investigations into the function of other hypothetical proteins ofN. gonorrhoeaediscovered in the expanding number of whole-genome sequences, in addition to revealing phenotypic differences between clinical and laboratory strains.

Thermosipho ferrireducens sp.nov., an anaerobic thermophilic iron(III)-reducing bacterium isolated from a deep-sea hydrothermal sulfide deposits

2021 ◽  
Vol 71 (7) ◽  
Author(s):  
Yao Chen ◽  
Yang He ◽  
Zongze Shao ◽  
Xiqiu Han ◽  
Danling Chen ◽  
...  
Keyword(s):  
16S Rrna ◽  
Sequence Similarity ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Rrna Gene ◽  
Phylogenetic Distance ◽  
16S Rrna Sequence ◽  
Content Type ◽  
Link Type ◽  
Carlsberg Ridge

A thermophilic, anaerobic, iron-reducing bacterium strain JL129W03T (=KCTC 15905T=MCCC 1A14213T) was isolated from a sulfide sample collected from the Daxi hydrothermal field (60.5° E, 6.4° N, 2919 m depth) on the Carlsberg Ridge, northwest Indian Ocean. Cells grew at 55–75 °C(optimum, 70 °C), at pH 6.0–9.0 (optimum, pH 6.0–7.0) and at NaCl concentrations of 1.5–4.5 % (w/v; optimum 3.0 %). Under optimal growth conditions, the generation time was around 85 min. The isolate was an obligate chemoorganoheterotroph, utilizing complex organic compounds, carbohydrates, organic acids and one amino acid. It was anaerobic and facultatively dependent on elemental sulphur and various forms of Fe(III) as an electron acceptor: insoluble forms and soluble forms. It did not reduce sulfite, sulphate, thiosulfate or nitrate. The G+C content of its genomic DNA was 34.0 mol%. Phylogenetic 16S rRNA gene sequence analyses revealed that its closest relative was Thermosipho atlanticus DV1140T with 95.81 % 16S rRNA sequence similarity. On the basis of physiological distinctness and phylogenetic distance, the isolate is considered to represent a novel species of the genus Thermosipho , for which the name Thermosipho ferrireducens sp. nov. is proposed. The type strain is strain JL129W03T (=KCTC 15905T;=MCCC 1A14213T).

Nocardioides dongkuii sp. nov. and Nocardioides lijunqiniae sp. nov., isolated from faeces of Tibetan antelope (Pantholops hodgsonii) and leaves of dandelion (Taraxacum officinale), respectively, on the Qinghai–Tibet Plateau

2021 ◽  
Vol 71 (7) ◽  
Author(s):  
Yanpeng Cheng ◽  
Yifan Jiao ◽  
Sihui Zhang ◽  
Jing Yang ◽  
Shan Lu ◽  
...  
Keyword(s):  
Type Species ◽  
Phylogenetic Trees ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Tibet Plateau ◽  
Bacterial Strains ◽  
Content Type ◽  
Link Type ◽  
Pr China ◽  
Qinghai Tibet Plateau

In the present study, four bacterial strains, two (S-713 T and 406) isolated from faecal samples of Tibetan antelopes and the other two (S-531 T and 1598) from leaves of dandelion collected on the Qinghai–Tibet Plateau of PR China, were analysed using a polyphasic approach. All four isolates were aerobic, rod-shaped, non-motile, oxidase-negative, Gram-stain-positive and catalase-positive. According to four phylogenetic trees, strain pairs S-713 T /406 and S-531 T /1598 form two independent branches belonging to the genus Nocardioides , and are closest to Nocardioides lianchengensis , Nocardioides dokdonensis , Nocardioides salarius , Nocardioides marinisabuli , Nocardioides psychrotolerans and Nocardioides szechwanensis . Although sharing MK8-(H 4 ) as their major isoprenoid quinone, strains S-713 T and S-531 T contained C 18 : 1  ω 9 c (24.64 and 16.34 %) and iso-C 16 : 0 (9.74 and 29.38 %), respectively, as their main fatty acids, with remarkable differences in their biochemical profiles but only slight ones in their optimal growth conditions. The chromosomes of strains S-713 T and S-531 T were 4 207 844 bp (G+C content, 73.0 mol%) and 4 809 817 bp (G+C content, 72.5 mol%), respectively. Collectively, the two strain pairs represent two separate novel species of the genus Nocardioides , for which the names Nocardioides dongkuii sp. nov. and Nocardioides lijunqiniae sp. nov. are proposed, with S-713 T (=JCM 33698 T =CGMCC 4.7660 T ) and S-531 T (=JCM 33468 T =CGMCC 4.7659 T ) as the respective type strains.

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