scholarly journals Investigating zinc toxicity responses in marine Prochlorococcus and Synechococcus

Microbiology ◽  
2021 ◽  
Vol 167 (6) ◽  
Author(s):  
Indrani Sarker ◽  
Lisa R. Moore ◽  
Sasha G. Tetu
Keyword(s):  
Primary Productivity ◽  
Physiological Responses ◽  
Ecological Niches ◽  
Zinc Toxicity ◽  
Plastic Pollution ◽  
Content Type ◽  
Marine Life ◽  
Link Type ◽  
Different Levels ◽  
Oxygenic Phototrophs

Marine plastic pollution is a growing concern worldwide and has the potential to impact marine life via leaching of chemicals, with zinc (Zn), a common plastic additive, observed at particularly high levels in plastic leachates in previous studies. At this time, however, little is known regarding how elevated Zn affects key groups of marine primary producers. Marine cyanobacterial genera Prochlorococcus and Synechococcus are considered to be some of the most abundant oxygenic phototrophs on earth, and together contribute significantly to oceanic primary productivity. Here we set out to investigate how two Prochlorococcus (MIT9312 and NATL2A) and two Synechococcus (CC9311 and WH8102) strains, representative of diverse ecological niches, respond to exposure to high Zn concentrations. The two genera showed differences in the timing and degree of growth and physiological responses to elevated Zn levels, with Prochlorococcus strains showing declines in their growth rate and photophysiology following exposure to 27 µg l−1 Zn, while Synechococcus CC9311 and WH8102 growth rates declined significantly on exposure to 52 and 152 µg l−1 Zn, respectively. Differences were also observed in each strain’s capacity to maintain cell wall integrity on exposure to different levels of Zn. Our results indicate that excess Zn has the potential to pose a challenge to some marine picocyanobacteria and highlights the need to better understand how different marine Prochlorococcus and Synechococcus strains may respond to increasing concentrations of Zn in some marine regions.

scholarly journals In silico analysis of the chemotactic system of Agrobacterium tumefaciens

2020 ◽  
Vol 6 (11) ◽  
Author(s):  
Nan Xu ◽  
Mingqi Wang ◽  
Xiaojing Yang ◽  
Yujuan Xu ◽  
Minliang Guo
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Type Species ◽  
Agar Plate ◽  
In Silico Analysis ◽  
Transformation Process ◽  
Receptor Protein ◽  
Ecological Niches ◽  
Content Type ◽  
Link Type ◽  
Major Cluster

Agrobacterium tumefaciens is an efficient tool for creating transgenic host plants. The first step in the genetic transformation process involves A. tumefaciens chemotaxis, which is crucial to the survival of A. tumefaciens in changeable, harsh and even contaminated soil environments. However, a systematic study of its chemotactic signalling pathway is still lacking. In this study, the distribution and classification of chemotactic genes in the model A. tumefaciens C58 and 21 other strains were annotated. Local blast was used for comparative genomics, and hmmer was used for predicting protein domains. Chemotactic phenotypes for knockout mutants of ternary signalling complexes in A. tumefaciens C58 were evaluated using a swim agar plate. A major cluster, in which chemotaxis genes were consistently organized as MCP (methyl-accepting chemotaxis protein), CheS, CheY1, CheA, CheR, CheB, CheY2 and CheD, was found in A. tumefaciens , but two coupling CheW proteins were located outside the ‘che’ cluster. In the ternary signalling complexes, the absence of MCP atu0514 significantly impaired A. tumefaciens chemotaxis, and the absence of CheA (atu0517) or the deletion of both CheWs abolished chemotaxis. A total of 465 MCPs were found in the 22 strains, and the cytoplasmic domains of these MCPs were composed of 38 heptad repeats. A high homology was observed between the chemotactic systems of the 22 A. tumefaciens strains with individual differences in the gene and receptor protein distributions, possibly related to their ecological niches. This preliminary study demonstrates the chemotactic system of A. tumefaciens , and provides some reference for A. tumefaciens sensing and chemotaxis to exogenous signals.

scholarly journals Phyllobacterium loti sp. nov. isolated from nodules of Lotus corniculatus

2014 ◽  
Vol 64 (Pt_3) ◽  
pp. 781-786 ◽  
Author(s):  
Maximo Sánchez ◽  
Martha-Helena Ramírez-Bahena ◽  
Alvaro Peix ◽  
María J. Lorite ◽  
Juan Sanjuán ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Sequence Similarity ◽  
Carbon Sources ◽  
Lotus Corniculatus ◽  
Culture Conditions ◽  
Rrna Gene ◽  
Content Type ◽  
Link Type ◽  
The 16S Rrna Gene

Strain S658T was isolated from a Lotus corniculatus nodule in a soil sample obtained in Uruguay. Phylogenetic analysis of the 16S rRNA gene and atpD gene showed that this strain clustered within the genus Phyllobacterium . The closest related species was, in both cases, Phyllobacterium trifolii PETP02T with 99.8 % sequence similarity in the 16S rRNA gene and 96.1 % in the atpD gene. The 16S rRNA gene contains an insert at the beginning of the sequence that has no similarities with other inserts present in the same gene in described rhizobial species. Ubiquinone Q-10 was the only quinone detected. Strain S658T differed from its closest relatives through its growth in diverse culture conditions and in the assimilation of several carbon sources. It was not able to reproduce nodules in Lotus corniculatus. The results of DNA–DNA hybridization, phenotypic tests and fatty acid analyses confirmed that this strain should be classified as a representative of a novel species of the genus Phyllobacterium , for which the name Phyllobacterium loti sp. nov. is proposed. The type strain is S658T( = LMG 27289T = CECT 8230T).

scholarly journals Faecalicoccus acidiformans gen. nov., sp. nov., isolated from the chicken caecum, and reclassification of Streptococcus pleomorphus (Barnes et al. 1977), Eubacterium biforme (Eggerth 1935) and Eubacterium cylindroides (Cato et al. 1974) as Faecalicoccus pleomorphus comb. nov., Holdemanella biformis gen. nov., comb. nov. and Faecalitalea cylindroides gen. nov., comb. nov., respectively, within the family Erysipelotrichaceae

2014 ◽  
Vol 64 (Pt_11) ◽  
pp. 3877-3884 ◽  
Author(s):  
Celine De Maesschalck ◽  
Filip Van Immerseel ◽  
Venessa Eeckhaut ◽  
Siegrid De Baere ◽  
Margo Cnockaert ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Type Species ◽  
Gene Sequence ◽  
Sequence Similarity ◽  
16S Rrna Gene Sequence ◽  
Rrna Gene ◽  
Rrna Gene Sequence ◽  
Content Type ◽  
Link Type

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.

The distributive knot: negotiators’ responsibility to untie complex demands

2017 ◽  
Vol 32 (4) ◽  
pp. 535-540 ◽  
Author(s):  
Alain Lempereur ◽  
Michele Pekar
Keyword(s):  
Demand Response ◽  
Automotive Industry ◽  
Design Methodology ◽  
Analytical Framework ◽  
Content Type ◽  
Business System ◽  
Response Dynamic ◽  
Managerial System ◽  
Deal Making ◽  
Different Levels

Purpose This article aims to explore the fundamental negotiation structure as a demand/response dynamic. It tests it in a complex business system, where a manager as a negotiator is confronted with multiple demands or pressures at different levels from a variety of stakeholders, both external and internal. Design/methodology/approach Based on concrete examples from the automotive industry, it presents an analytical framework to tackle all negotiation interactions. Findings This article suggests that it is possible to describe all negotiation interactions, whether they are simple or complex, through a demand/response framework. Originality/value This contribution examines a fundamental structure for negotiation responsibility – the demand/response dynamic – defining the mission of any negotiator in deal-making or dispute resolution as to try to supply a response to the expressed crossed demands. Second, the proposed theoretical model of demand/response is transposed and tested in a managerial system where a sales negotiator is confronted with demands from more sources, both external and internal, with the responsibility to satisfy as best as possible the various stakeholders and the capacity to address each of them with different moves.

scholarly journals EspM Is a Conserved Transcription Factor That Regulates Gene Expression in Response to the ESX-1 System

mBio ◽  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Kevin G. Sanchez ◽  
Micah J. Ferrell ◽  
Alexandra E. Chirakos ◽  
Kathleen R. Nicholson ◽  
Robert B. Abramovitch ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Protein Transport ◽  
Transcriptional Response ◽  
Secretion System ◽  
Pathogenic Species ◽  
Macrophage Infection ◽  
Content Type ◽  
Link Type ◽  
Phagosomal Membrane

ABSTRACT Pathogenic mycobacteria encounter multiple environments during macrophage infection. Temporally, the bacteria are engulfed into the phagosome, lyse the phagosomal membrane, and interact with the cytosol before spreading to another cell. Virulence factors secreted by the mycobacterial ESX-1 (ESAT-6-system-1) secretion system mediate the essential transition from the phagosome to the cytosol. It was recently discovered that the ESX-1 system also regulates mycobacterial gene expression in Mycobacterium marinum (R. E. Bosserman, T. T. Nguyen, K. G. Sanchez, A. E. Chirakos, et al., Proc Natl Acad Sci U S A 114:E10772–E10781, 2017, https://doi.org/10.1073/pnas.1710167114), a nontuberculous mycobacterial pathogen, and in the human-pathogenic species M. tuberculosis (A. M. Abdallah, E. M. Weerdenburg, Q. Guan, R. Ummels, et al., PLoS One 14:e0211003, 2019, https://doi.org/10.1371/journal.pone.0211003). It is not known how the ESX-1 system regulates gene expression. Here, we identify the first transcription factor required for the ESX-1-dependent transcriptional response in pathogenic mycobacteria. We demonstrate that the gene divergently transcribed from the whiB6 gene and adjacent to the ESX-1 locus in mycobacterial pathogens encodes a conserved transcription factor (MMAR_5438, Rv3863, now espM). We prove that EspM from both M. marinum and M. tuberculosis directly and specifically binds the whiB6-espM intergenic region. We show that EspM is required for ESX-1-dependent repression of whiB6 expression and for the regulation of ESX-1-associated gene expression. Finally, we demonstrate that EspM functions to fine-tune ESX-1 activity in M. marinum. Taking the data together, this report extends the esx-1 locus, defines a conserved regulator of the ESX-1 virulence pathway, and begins to elucidate how the ESX-1 system regulates gene expression. IMPORTANCE Mycobacterial pathogens use the ESX-1 system to transport protein substrates that mediate essential interactions with the host during infection. We previously demonstrated that in addition to transporting proteins, the ESX-1 secretion system regulates gene expression. Here, we identify a conserved transcription factor that regulates gene expression in response to the ESX-1 system. We demonstrate that this transcription factor is functionally conserved in M. marinum, a pathogen of ectothermic animals; M. tuberculosis, the human-pathogenic species that causes tuberculosis; and M. smegmatis, a nonpathogenic mycobacterial species. These findings provide the first mechanistic insight into how the ESX-1 system elicits a transcriptional response, a function of this protein transport system that was previously unknown.

scholarly journals Amphritea ceti sp. nov., isolated from faeces of Beluga whale (Delphinapterus leucas)

2014 ◽  
Vol 64 (Pt_12) ◽  
pp. 4068-4072 ◽  
Author(s):  
Young-Ok Kim ◽  
Sooyeon Park ◽  
Doo Nam Kim ◽  
Bo-Hye Nam ◽  
Sung-Min Won ◽  
...  
Keyword(s):  
Phylogenetic Trees ◽  
Sequence Similarity ◽  
Beluga Whale ◽  
Delphinapterus Leucas ◽  
Rrna Gene ◽  
Phenotypic Properties ◽  
Content Type ◽  
Link Type ◽  
Beluga Whale Delphinapterus Leucas ◽  
Type Strains

A Gram-stain-negative, aerobic, non-spore-forming, non-flagellated and rod-shaped or ovoid bacterial strain, designated RA1T, was isolated from faeces collected from Beluga whale (Delphinapterus leucas) in Yeosu aquarium, South Korea. Strain RA1T grew optimally at 25 °C, at pH 7.0–8.0 and in the presence of 2.0 % (w/v) NaCl. Neighbour-joining, maximum-likelihood and maximum-parsimony phylogenetic trees based on 16S rRNA gene sequences revealed that strain RA1T joins the cluster comprising the type strains of three species of the genus Amphritea , with which it exhibited 95.8–96.0 % sequence similarity. Sequence similarities to the type strains of other recognized species were less than 94.3 %. Strain RA1T contained Q-8 as the predominant ubiquinone and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C18 : 1ω7c and C16 : 0 as the major fatty acids. The major polar lipids of strain RA1T were phosphatidylethanolamine, phosphatidylglycerol, two unidentified lipids and one unidentified aminolipid. The DNA G+C content of strain RA1T was 47.4 mol%. The differential phenotypic properties, together with the phylogenetic distinctiveness, revealed that strain RA1T is separated from other species of the genus Amphritea . On the basis of the data presented, strain RA1T is considered to represent a novel species of the genus Amphritea , for which the name Amphritea ceti sp. nov. is proposed. The type strain is RA1T ( = KCTC 42154T = NBRC 110551T).

scholarly journals Death by Cystine: an Adverse Emergent Property from a Beneficial Series of Reactions

2015 ◽  
Vol 197 (23) ◽  
pp. 3626-3628 ◽  
Author(s):  
Larry Reitzer
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Sulfur Metabolism ◽  
Emergent Property ◽  
Futile Cycle ◽  
Content Type ◽  
Link Type

In this issue of theJournal of Bacteriology, Chonoles Imlay et al. (K. R. Chonoles Imlay, S. Korshunov, and J. A. Imlay, J Bacteriol 197:3629–3644, 2015,http://dx.doi.org/10.1128/JB.00277-15) show that oxidative stress kills sulfur-restrictedEscherichia coligrown with sublethal H2O2when challenged with cystine. Killing requires rapid and seemingly unregulated cystine transport and equally rapid cystine reduction to cysteine. Cysteine export completes an energy-depleting futile cycle. Each reaction of the cycle could be beneficial. Together, a cystine-mediated vulnerability emerges during the transition from a sulfur-restricted to a sulfur-replete environment, perhaps because of complexities of sulfur metabolism.

scholarly journals Pseudoseohaeicola caenipelagi gen. nov., sp. nov., isolated from a tidal flat

2015 ◽  
Vol 65 (Pt_6) ◽  
pp. 1819-1824 ◽  
Author(s):  
Sooyeon Park ◽  
Ji-Min Park ◽  
Chul-Hyung Kang ◽  
Song-Gun Kim ◽  
Jung-Hoon Yoon
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Tidal Flat ◽  
Type Strain ◽  
Type Species ◽  
Phylogenetic Trees ◽  
Sequence Similarity ◽  
Rrna Gene ◽  
Content Type ◽  
Link Type

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).

Litorilinea aerophila gen. nov., sp. nov., an aerobic member of the class Caldilineae , phylum Chloroflexi , isolated from an intertidal hot spring

2013 ◽  
Vol 63 (Pt_3) ◽  
pp. 1149-1154 ◽  
Author(s):  
Varsha Kale ◽  
Snædís H. Björnsdóttir ◽  
Ólafur H. Friðjónsson ◽  
Sólveig K. Pétursdóttir ◽  
Sesselja Ómarsdóttir ◽  
...  
Keyword(s):  
Type Species ◽  
Hot Spring ◽  
Sequence Similarity ◽  
Rrna Gene ◽  
Content Type ◽  
Phenotypic Differences ◽  
Link Type ◽  
Fermentative Growth ◽  
Distinct Lineage ◽  
Ph Range

A thermophilic, aerobic, Gram-stain-negative, filamentous bacterium, strain PRI-4131T, was isolated from an intertidal hot spring in Isafjardardjup, NW Iceland. The strain grew chemo-organotrophically on various carbohydrates. The temperature range for growth was 40–65 °C (optimum 55 °C), the pH range was pH 6.5–9.0 (optimum pH 7.0) and the NaCl range was 0–3 % (w/v) (optimum 0.5 %). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain PRI-4131T represented a distinct lineage within the class Caldilineae of the phylum Chloroflexi. The highest levels of sequence similarity, about 91 %, were with Caldilinea aerophila STL-6-O1T and Caldilinea tarbellica D1-25-10-4T. Fermentative growth was not observed for strain PRI-4131T, which, in addition to other characteristics, distinguished it from the two Caldilinea species. Owing to both phylogenetic and phenotypic differences from the described members of the class Caldilineae , we propose to accommodate strain PRI-4131T in a novel species in a new genus, Litorilinea aerophila gen. nov., sp. nov. The type strain of Litorilinea aerophila is PRI-4131T ( = DSM 25763T  = ATCC BAA-2444T).

scholarly journals Sphingobacterium yanglingense sp. nov., isolated from the nodule surface of soybean

2014 ◽  
Vol 64 (Pt_11) ◽  
pp. 3862-3866 ◽  
Author(s):  
Shi Peng ◽  
Dong Dan Hong ◽  
Yang Bing Xin ◽  
Li Ming Jun ◽  
Wei Ge Hong
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Polar Lipids ◽  
Rrna Gene ◽  
Content Type ◽  
Link Type ◽  
Gram Staining ◽  
Physiological And Biochemical Characteristics ◽  
Gene Sequence Analysis ◽  
Type Strains

A Gram-staining-negative, non-motile, catalase- and oxidase-positive strain, designated CCNWSP36-1T, was isolated from the nodule surface of soybean [Glycine max (L.) Merrill] cultivar Zhonghuang 13. The 16S rRNA gene sequence analysis clearly showed that the isolate represented a member of the genus Sphingobacterium . On the basis of pairwise comparisons of 16S rRNA gene sequences, strain CCNWSP36-1T showed 96.8 % similarity to Sphingobacterium nematocida CCTCC AB 2010390T and less than 95.2 % similarity to other members of the genus Sphingobacterium . Growth of strain CCNWSP36-1T occurred at 10–40 °C and at pH 5.0–9.0. The NaCl range (w/v) for growth was 0–4 %. The predominant isoprenoid quinone was MK-7. The polar lipids were phosphatidylethanolamine and several unidentified polar lipids. Sphingolipid was present. The major fatty acids were iso-C15 : 0 and summed feature 3 (comprising C16 : 1ω6c and/or C16 : 1ω7c). The G+C content of the genomic DNA was 41.1 mol%. As the physiological and biochemical characteristics of strain CCNWSP36-1T and the type strains of its closest phylogenetic neighbours showed clear differences, a novel species, Sphingobacterium yanglingense, is proposed. The type strain is CCNWSP36-1T ( = ACCC 19328T = JCM 30166T).

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