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To explore the diversity and application potential of Antarctic microorganisms, 1208 strains bacteria and fungi were isolated from 5 samples collected from the Fildes Peninsula during China’s 27th and 31st Antarctic expeditions. By using 16S and ITS sequence similarity alignment, 83 strains bacteria belonging to 20 genera and 30 strains fungi belon...
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Context 1
... EtOAc extracts of solid MS19 rice medium were partitioned between petroleum ether and 90% aqueous MeOH. The resulting MeOH phase was fractionated using a silica column, Sephadex LH-20, and then semipreparative reversed-phase HPLC to obtain compounds 1-4 (Figure 4). The culture on solid rice medium was soaked in acetone, cut into small pieces and maintained for 1 day. ...
Context 2
... EtOAc extract of rice fermentation of Aspergillus sydowii MS-19 was subjected to silica gel column chromatography and further purified by HPLC to obtain four known compounds (1-4) (Figure 4). The spectroscopic data of the identified compounds were compared with those reported in the literature, and versicone A (1), versicone B (2), 4-methyl-5,6-dihydro-2H-pyran-2-one (3), and (R)-(+)-sydowic acid (4) (d, J = 8.5 Hz, H-6), δ H 7.58 (t, J = 8.5 Hz, H-7), δ H 7.01 (dd, J = 8.5, 0.5 Hz, H-8)]. ...
Citations
... Several studies dealing with bacterial diversity and bioprospecting for cold-active hydrolytic enzymes from culturable bacteria of various Antarctic ecosystems have been performed. These have shown that these extreme environments provide a good setting for screening this sort of enzyme with potential biotechnological applications and economic benefits [4][5][6][7]. ...
Background
Antarctica is one of the harshest environments in the world. Despite this fact, it has been colonized by microorganisms, which had to develop different adaptations in order to survive. By studying their enzymes, we can harness these adaptations in order to use them in various industrial processes. Keratinases (E.C. 3.4.99.11) are characterized by their robustness in withstanding extreme conditions and, along with other enzymes, are commonly added to laundry detergents, which makes their study of industrial interest.
Results
In this work, a novel keratinase producer, Pedobacter sp. 3.14.7 (MF 347939.1), isolated from Antarctic birds’ nests, was identified. This psychrotolerant isolate displays a typical psychrotolerant growth pattern, with an optimal temperature of 20 °C (μmax=0.23 h ⁻¹ ). After 238 h, maximum proteolytic (22.00 ± 1.17 U ml ⁻¹ ) and keratinolytic (33.04 ± 1.09 U ml ⁻¹ ) activities were achieved with a feather sample conversion of approximately 85%. The keratinase present in crude extract was characterized as a metalloprotease with a molecular weight of 25 kDa, stable in a wide range of pH, with an optimum pH of 7.5. Optimum temperature was 55 °C. Wash performance at 20 °C using this crude extract could remove completely blood stain from cotton cloth.
Conclusion
We report a new keratinolytic bacteria from maritime Antarctica. Among its biochemical characteristics, its stability in the presence of different detergents and bleaching agents and its wash performance showed promising results regarding its potential use as a laundry detergent additive.
... De esta forma, el continente antártico se ha transformado en un gran reservorio de biodiversidad bacteriana para la producción de sustancias antimicrobianas (Núñez-Montero et al. 2019). Si bien la mayor parte de las investigaciones se centra en bacterias que provienen de medioambientes acuáticos (Van Trappen et al. 2002), los estudios realizados en el medioambiente sólido de la Antártica han identificado en estos microorganismos un polo de desarrollo biotecnológico (Cong et al. 2020;Nichols et al. 2002). Asociados a compuestos antimicrobianos, se han caracterizado Pseudomonas sp. ...
The sustained decrease in the availability of new antimicrobial molecules for thera peutic use in recent decades and the large increase in microorganisms resistant to these compounds makes it necessary to search for new substances with antimicrobial properties. Extreme environments, where there is little availability of nutrients, are favorable scenarios to search for this type of compounds, since bacteria compete with other bacteria or other organisms to position themselves in the ecological niche and secrete, associated with their secondary metabolism, a series of molecules that inhibit or kill other microorganisms thus preventing their proliferation. Our group has a collection of rhizosphere bacteria from soil of the Antarctic continent that has ability to grow under conditions of food deprivation and at 4°C. Due to the extreme habitat where they develop, Antarctic soil bacteria are in constant competition for nutritional resources and therefore develop different strategies to colonize their ecological niche and compete with other microorganisms of the Antarctic microbiota. The objective of this work was to identify bacteria isolated from the rhizosphere of Deschampsia antarctica Desv. that inhibit the growth of bacteria and fungi that are pathogenic for humans. From a collection of 55 rhizosphere isolates of the Deschampsia antarctica Desv. we identified 11 isolates with the capacity to eliminate human pathogenic bacteria, but no isolate from the collection eliminated the Candida albicans fungus. The 11 Antarctic bacteria with antibacterial capacity are strict aerobic Gram-negative bacilli, psychro phile to the genus Pseudomonas.
... ± 2.9 24.4 ± 5.0/--/--/-HSX8#- 6 20.6 ± 1.4/--/13.7 ± 0.1 22.2 ± 2.7/10.9 ± 8.8 16.3 ± 1.9/--/-HSX8#- 9 15.9 ± 2.5/-11.1 ± 3.8/-21.9 ± 0.1/--/--/-JQW- 6 24.4 ± 4.7/-11.0 ...
With the increasingly serious antimicrobial resistance, discovering novel antibiotics has grown impendency. The Antarctic abundant microbial resources, especially fungi, can produce unique bioactive compounds for adapting to the hostile environment. In this study, three Antarctic fungi, Chrysosporium sp. HSXSD-11-1, Cladosporium sp. HSXSD-12 and Acrostalagmus luteoalbus CH-6, were found to have the potential to produce antimicrobial compounds. Furthermore, the crude extracts of CH-6 displayed the strongest antimicrobial activities with 72.3–84.8% growth inhibition against C. albicans and Aeromonas salmonicida. The secondary metabolites of CH-6 were researched by bioactivity tracking combined with molecular networking and led to the isolation of two new α-pyrones, acrostalapyrones A (1) and B (2), along with one known analog (3), and three known indole diketopiperazines (4–6). The absolute configurations of 1 and 2 were identified through modified Mosher’s method. Compounds 4 and 6 showed strong antimicrobial activities. Remarkably, the antibacterial activity of 6 against A. salmonicida displayed two times higher than that of the positive drug Ciprofloxacin. This is the first report to discover α-pyrones from the genus Acrostalagmus, and the significant antimicrobial activities of 4 and 6 against C. albicans and A. salmonicida. This study further demonstrates the great potential of Antarctic fungi in the development of new compounds and antibiotics.
... As a continuing effort in the search for new bioactive metabolites from the endophytic fungi (Tian et al., 2015a(Tian et al., ,b, 2018aCong et al., 2020), three fungal strains isolated from a marine sponge were subjected to chemical [Thin layer chromatography (TLC) and high pressure liquid chromatography (HPLC)] and antibacterial activity screening. Alternaria sp. ...
At present, foodborne diseases (FBDs) caused by bacteria are gradually increasing every year, and the development of new antibiotics is an urgent necessity for human beings. To find novel antibacterial compounds, three sponge-derived fungal strains (SCSIOS02F40, F46, and F49) were investigated. As a result, Alternaria sp. SCSIOS02F49 was selected for investigation on its secondary metabolites because its ethyl acetate (EtOAc) extract of potato dextrose broth (PDB) culture showed rich metabolites and strong antibacterial activity. Two new dibenzopyrones with rare sulfate group (1–2), together with 10 known compounds (3–12), were isolated from the Alternaria sp. SCSIOS02F49. Their structures were confirmed by nuclear magnetic resonance (NMR), mass spectrometry (MS) data, and comparison with data from the relevant literature. Almost all compounds showed moderate inhibitory activity against eight foodborne bacteria (FBB) with minimum inhibitory concentration (MIC) values in the range of 15.6–250 μg/ml, and minimum bactericidal concentration (MBC) values in the range of 31.3–250 μg/ml. The antibacterial mechanism of compound 1 was preliminarily investigated using growth curves, scanning electron microscopy (SEM), and flow cytometry (FCM), which revealed that compound 1 altered the external structure of Staphylococcus aureus and caused the rupture or deformation of the cell membranes. This research provides lead compounds for the development of new antibiotics or microbial preservatives.
... Polar regions, which harbor diverse groups of fauna and microorganisms including bacteria, actinomycetes, and fungi, have drawn attention as rich sources of diverse secondary metabolites with significant anti-bacterial, anti-tumor, anti-virus, and anti-inflammatory effects [8,9]. Antarctica, which harbors a cold, dry climate with intense solar radiation, has nurtured a number of unique microbial resources that have been attracting increasing attention [10]. ...
Microglia play a significant role in immune defense and tissue repair in the central nervous system (CNS). Microglial activation and the resulting neuroinflammation play a key role in the pathogenesis of neurodegenerative disorders. Recently, inflammation reduction strategies in neurodegenerative diseases have attracted increasing attention. Herein, we discovered and evaluated the anti-neuroinflammatory potential of compounds from the Antarctic fungi strain Aspergillus sp. SF-7402 in lipopolysaccharide (LPS)-stimulated BV2 cells. Four metabolites were isolated from the fungi through chemical investigations, namely, 5-methoxysterigmatocystin (1), sterigmatocystin (2), aversin (3), and 6,8-O-dimethylversicolorin A (4). Their chemical structures were elucidated by extensive spectroscopic analysis and HR-ESI-MS, as well as by comparison with those reported in literature. Anti-neuroinflammatory effects of the isolated metabolites were evaluated by measuring the production of nitric oxide (NO), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 in LPS-activated microglia at non-cytotoxic concentrations. Sterigmatocystins (1 and 2) displayed significant effects on NO production and mild effects on TNF-α and IL-6 expression inhibition. The molecular mechanisms underlying this activity were investigated using Western blot analysis. Sterigmatocystin treatment inhibited NO production via downregulation of inducible nitric oxide synthase (iNOS) expression in LPS-stimulated BV2 cells. Additionally, sterigmatocystins reduced nuclear translocation of NF-κB. These results suggest that sterigmatocystins present in the fungal strain Aspergillus sp. are promising candidates for the treatment of neuroinflammatory diseases.
... Massilia spp. from Antarctica are reported in studies focusing on soils [3,21,22] or the aquatic environment [2,23]. Cold-adapted bacteria are able to produce a variety of pigments as a protective strategy against environmental stresses such as low temperature, oxidative stress, and ultraviolet radiation [24]. ...
A group of seven bacterial strains producing blue-purple pigmented colonies on R2A agar was isolated from freshwater samples collected in a deglaciated part of James Ross Island and Eagle Island, Antarctica, from 2017–2019. The isolates were psychrophilic, oligotrophic, resistant to chloramphenicol, and exhibited strong hydrolytic activities. To clarify the taxonomic position of these isolates, a polyphasic taxonomic approach was applied based on sequencing of the 16S rRNA, gyrB and lepA genes, whole-genome sequencing, rep-PCR, MALDI-TOF MS, chemotaxonomy analyses and biotyping. Phylogenetic analysis of the 16S rRNA gene sequences revealed that the entire group are representatives of the genus Massilia. The closest relatives of the reference strain P8398T were Massilia atriviolacea, Massilia violaceinigra, Massilia rubra, Massilia mucilaginosa, Massilia aquatica, Massilia frigida, Massilia glaciei and Massilia eurypsychrophila with a pairwise similarity of 98.6–100% in the 16S rRNA. The subsequent gyrB and lepA sequencing results showed the novelty of the analysed group, and the average nucleotide identity and digital DNA–DNA hybridisation values clearly proved that P8398T represents a distinct Massilia species. After all these results, we nominate a new species with the proposed name Massilia antarctica sp. nov. The type strain is P8398T (=CCM 8941T = LMG 32108T).
... Compound 134 showed potent antifungal activity against C. albicans with a MIC value of 3.91 µg/ml. Interestingly, the addition of a methoxy group in C-6 position of 134 as in compound 135 led to lower antifungal properties against C. aureus, as 135 presented a MIC value of 125 µg/ml (Cong et al. 2020). ...
Natural products represent a promising strategy for the discovery of new drug leads. Despite the effort of industry and academia, the investigations of natural products are concentrated in tropical and sub-tropical areas. Polar regions, such as the Arctic and Antarctica, are the most extreme and isolated environments on earth. Indeed, their severe climate conditions include low temperatures, high ultraviolet radiation, freeze–thaw cycles, and strong winds. These regions harbor a rich and underexplored biodiversity with immeasurable aggregate biotechnological potential. To survive on the poles, organisms have evolved and acquired different strategies including distinctive biological machineries, leading to the production of a unique and diverse array of organic molecules which can be used as prototypes for the development of new therapeutic agents. In this review, we summarize the occurrence of secondary metabolites from the Arctic and Antarctic organisms as well as their bioactivity from 2018 to 2020. Besides, we illustrate the collection sites and countries contributions to the field of polar natural products.Graphical abstract
... doi: 10.1007/s11101-014-9365-1 Wang, S., Zheng, Y., Gu, C., He, C., Yang, M., Zhang, X., et al. (2018) INTRODUCTION Tremulanes, a family of sesquiterpenoids with characteristic structures of 5/7 fused bicyclic system, were rarely discovered in nature until 2015 (Guo et al., 2016). However, from 2016 to 2020, about 60 tremulane derivatives were found (Guo et al., 2016;Isaka et al., 2016;Wu, 2016;Chen et al., 2017Chen et al., , 2018Cong et al., 2020;Wang et al., 2017Wang et al., , 2020Ding et al., 2018Ding et al., , 2019Ding et al., , 2020aZhou et al., 2018;Duan et al., 2019;Wu et al., , 2020He et al., 2020;Lee et al., 2020;, and the number is twice as many as before. Most of them were isolated from the cultures of the basidiomycetes Irpex lacteus (Chen et al., 2018Ding et al., 2018Ding et al., , 2019Ding et al., , 2020aZhou et al., 2018;Duan et al., 2019;Wang et al., 2020). ...
... Some of them were discovered to have different bioactivities, such as tremutin A with the inhibition of the lipopolysaccharide-induced proliferation of B lymphocyte cells , and 5-demethyl conocenol C showed antifungal activities . The extreme environments of Antarctica, including cold, dry climate and intense solar radiations, have nurtured a number of unique microbial resources (Cong et al., 2020). It has been proved that Antarctic microorganisms, especially fungi, have the potential capacity to produce novel secondary metabolites to adapt to the harsh environments (Kwon et al., 2017;Rusman et al., 2018;Yu et al., 2019;. ...
... Modern culture-independent studies like metagenomics using nextgeneration sequencing indicate that the microbial diversity in polar regions is much higher than previously thought (Chandrakar and Gupta 2017). Particularly, maritime Antarctica represents an interesting source for the investigation of novel bacterial species (Cong et al. 2020;Lambrechts et al. 2019;Roldan et al. 2020). With the aim of isolating novel psychrophilic bacterial species for potential biotechnological application from several sources in the Fildes peninsula (Antarctica), a strain designated 16F T was selected for further characterization. ...
The rod-shaped and Gram-stain-negative bacterial strain 16F T , isolated from an air sample collected at King George Island, maritime Antarctica, was investigated to determine its taxonomic status. Strain 16F T is strictly aerobic, catalase positive, oxidase positive and non-motile. Strain 16F T hydrol-yses casein, lecithin, Tween 20, 60 and 80, but not aesculin, gelatin and starch. Growth of strain 16F T is observed at 0-20°C (optimum 10°C), pH 5.0-8.0 (optimum pH 6.0), and in the presence of 0-2.0% NaCl (optimum 0.5%). The predominant menaqui-none is MK-6, and the major fatty acids comprise anteiso-C 15:0 and iso-C 15:0. The major polar lipids are phosphatidylethanolamine, ornithine lipid OL2, unidentified phospholipid PL1 and the unidentified lipids L3 and L6 lacking functional groups. The DNA G ? C content based on the draft genome sequence is 32.3 mol%. Sequence analysis of the 16S rRNA gene indicates the highest similarity to Kaistella palustris 3A10 T (95.4%), Kaistella chaponensis Sa 1147-06 T (95.2%), Kaistella antarctica AT1013 T (95.1%), Kaistella carnis NCTC 13525 T (95.1%) and below 95.0% to other species with validly published names. Phylogenetic analysis based on 16S rRNA gene and whole-genome sequences places strain 16F T in a Supplementary Information The online version contains supplementary material available at https://doi.().,-volV) (01234567 89().,-volV) distinct branch, indicating a separate lineage within the family Weeksellaceae. Based on the data from our polyphasic approach, 16F T represents a novel species of a new genus, for which the name Frigoriflavimonas asaccharolytica gen. nov, sp. nov. is proposed. The type strain is 16F T (= CCM 8975 T = CGMCC No.1.16844 T).
... Tremulanes, a family of sesquiterpenoids with characteristic structures of 5/7 fused bicyclic system, were rarely discovered in nature until 2015 (Guo et al., 2016). However, from 2016 to 2020, about 60 tremulane derivatives were found (Guo et al., 2016;Isaka et al., 2016;Wu, 2016;Chen et al., 2017Chen et al., , 2018Cong et al., 2020;Wang et al., 2017Wang et al., , 2020Ding et al., 2018Ding et al., , 2019Ding et al., , 2020aZhou et al., 2018;Duan et al., 2019;Wu et al., 2019Wu et al., , 2020He et al., 2020;Lee et al., 2020;Shi et al., 2020;, and the number is twice as many as before. Most of them were isolated from the cultures of the basidiomycetes Irpex lacteus (Chen et al., 2018(Chen et al., , 2020Ding et al., 2018Ding et al., , 2019Ding et al., , 2020aZhou et al., 2018;Duan et al., 2019;Wu et al., 2019;Shi et al., 2020;Wang et al., 2020). ...
... The extreme environments of Antarctica, including cold, dry climate and intense solar radiations, have nurtured a number of unique microbial resources (Cong et al., 2020). It has been proved that Antarctic microorganisms, especially fungi, have the potential capacity to produce novel secondary metabolites to adapt to the harsh environments (Kwon et al., 2017;Rusman et al., 2018;Yu et al., 2019;. ...
The fungal strains Pseudogymnoascus are a kind of psychrophilic pathogenic fungi that are ubiquitously distributed in Antarctica, while the studies of their secondary metabolites are infrequent. Systematic research of the metabolites of the fungus Pseudogymnoascus sp. HSX2#-11 led to the isolation of six new tremulane sesquiterpenoids pseudotremulanes A–F (1–6), combined with one known analog 11,12-epoxy-12β-hydroxy-1-tremulen-5-one (7), and five known steroids (8–12). The absolute configurations of the new compounds (1–6) were elucidated by their ECD spectra and ECD calculations. Compounds 1–7 were proved to be isomeride structures with the same chemical formula. Compounds 1/2, 3/4, 1/4, and 2/3 were identified as four pairs of epimerides at the locations of C-3, C-3, C-9, and C-9, respectively. Compounds 8 and 9 exhibited cytotoxic activities against human breast cancer (MDA-MB-231), colorectal cancer (HCT116), and hepatoma (HepG2) cell lines. Compounds 9 and 10 also showed antibacterial activities against marine fouling bacteria Aeromonas salmonicida. This is the first time to find terpenoids and steroids in the fungal genus Pseudogymnoascus.
