antarctic bacterium
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2022 ◽  
Vol 61 ◽  
pp. 100922
Author(s):  
Christopher Riccardi ◽  
Caterina D'Angelo ◽  
Marzia Calvanese ◽  
Annarita Ricciardelli ◽  
Maria Luisa Tutino ◽  
...  

Biomolecules ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1552
Author(s):  
Xiaoyu Liu ◽  
Mingyang Zhou ◽  
Shu Xing ◽  
Tao Wu ◽  
Hailun He ◽  
...  

Esterases represent an important class of enzymes with a wide variety of industrial applications. A novel hormone-sensitive lipase (HSL) family esterase, Est19, from the Antarctic bacterium Pseudomonas sp. E2-15 is identified, cloned, and expressed. The enzyme possesses a GESAG motif containing an active serine (S) located within a highly conserved catalytic triad of Ser155, Asp253, and His282 residues. The catalytic efficiency (kcat/Km) of Est19 for the pNPC6 substrate is 148.68 s−1mM−1 at 40 °C. Replacing Glu154 juxtaposed to the critical catalytic serine with Asp (E154→D substitution) reduced the activity and catalytic efficiency of the enzyme two-fold, with little change in the substrate affinity. The wild-type enzyme retained near complete activity over a temperature range of 10–60 °C, while ~50% of its activity was retained at 0 °C. A phylogenetic analysis suggested that Est19 and its homologs may represent a new subfamily of HSL. The thermal stability and stereo-specificity suggest that the Est19 esterase may be useful for cold and chiral catalyses.


Water ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2367
Author(s):  
Syazani Darham ◽  
Sharifah Nabilah Syed-Muhaimin ◽  
Kavilasni Subramaniam ◽  
Azham Zulkharnain ◽  
Noor Azmi Shaharuddin ◽  
...  

The versatility of a rare metal, molybdenum (Mo) in many industrial applications is one of the reasons why Mo is currently one of the growing environmental pollutants worldwide. Traces of inorganic contaminants, including Mo, have been discovered in Antarctica and are compromising the ecosystem. Bioremediation utilising bacteria to transform pollutants into a less toxic form is one of the approaches for solving Mo pollution. Mo reduction is a process of transforming sodium molybdate with an oxidation state of 6+ to Mo-blue, an inert version of the compound. Although there are a few Mo-reducing microbes that have been identified worldwide, only two studies were reported on the microbial reduction of Mo in Antarctica. Therefore, this study was done to assess the ability of Antarctic bacterium, Arthrobacter sp. strain AQ5-05, in reducing Mo. Optimisation of Mo reduction in Mo-supplemented media was carried out using one-factor-at-a-time (OFAT) and response surface methodology (RSM) approaches. Through OFAT, Mo was reduced optimally with substrate concentration of sucrose, ammonium sulphate, and molybdate at 1 g/L, 0.2 g/L, and 10 mM, respectively. The pH and salinity of the media were the best at 7.0 and 0.5 g/L, respectively, while the optimal temperature was at 10 °C. Further optimisation using RSM showed greater Mo-blue production in comparison to OFAT. The strain was able to stand high concentration of Mo and low temperature conditions, thus showing its potential in reducing Mo in Antarctica by employing conditions optimised by RSM.


Antibiotics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 944
Author(s):  
Rosanna Papa ◽  
Gianluca Vrenna ◽  
Caterina D’Angelo ◽  
Angela Casillo ◽  
Michela Relucenti ◽  
...  

Pseudomonas aeruginosa is an opportunistic pathogen often involved in airway infections of cystic fibrosis (CF) patients. Its pathogenicity is related to several virulence factors, such as biofilm formation, motility and production of toxins and proteases. The expression of these virulence factors is controlled by quorum sensing (QS). Thus, QS inhibition is considered a novel strategy for the development of antipathogenic compounds acting on specific bacterial virulence programs without affecting bacterial vitality. In this context, cold-adapted marine bacteria living in polar regions represent an untapped reservoir of biodiversity endowed with an interesting chemical repertoire. In this paper, we investigated the biological activity of a supernatant derived from a novel Antarctic bacterium (SN_TAE2020) against specific virulence factors produced by P. aeruginosa strains isolated from FC patients. Our results clearly show a reduction in pyocyanin and protease production in the presence of SN_TAE2020. Finally, SN_TAE2020 was also able to strongly affect swarming and swimming motility for almost all tested strains. Furthermore, the effect of SN_TAE2020 was investigated on biofilm growth and texture, captured by SEM analysis. In consideration of the novel results obtained on clinical strains, polar bacteria might represent potential candidates for the discovery of new compounds limiting P. aeruginosa virulence in CF patients.


2020 ◽  
Author(s):  
Paula de França ◽  
Jonas Costa ◽  
Taícia Fill ◽  
Marcelo Lancelotti ◽  
Ana Ruiz ◽  
...  

Abstract The antimicrobial resistance requires the urgent mining of new antimicrobials. Actinobacteria, specially Streptomyces genus, are responsible for production of numerous clinical antibiotics and anticancer agents. The use of genome mining can reveal the genetic potential of a strain to produce natural products, however the potential may not be express under laboratory conditions. In the present study, the Antarctic bacterium was taxonomically affiliated as Streptomyces albidoflavus, ANT_B131. The crude extracts showed antimicrobial activity against fungi, Gram-positive and Gram-negative bacteria and antiproliferative activity against five human tumor cell lines. Whole genome sequencing reveals a 6.96 Mb genome size and the genome mining showed 24 BGCs, representing 13.3% of the genome. The use of three culture media and extraction methods reveal the expression and recovery of 20% of the BGCs. The natural products identified were surugamide A, surugamide D, desferrioxamine B + Al, desferrioxamine E, and ectoine. This study reveals the potential of S. albidoflavus ANT_B131 as a natural product producer. Yet, the diversity of culture media and extraction methods could enhance the BGCs expression and recovery of natural products, and could be a new strategy to intensify the BGC expression of natural products.


2020 ◽  
Vol 497 ◽  
pp. 108125
Author(s):  
Rossella Di Guida ◽  
Angela Casillo ◽  
Maria Michela Corsaro

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