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Zakharova, O. S.; Zenova, G. M.; Zvyagintsev, D. G.

doi:10.1023/a:1022294526830

Cited by 27 publications

(4 citation statements)

References 7 publications

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“…These taxa are involved in the fast turnover of litter and consequently fast degradation of cellulose and hemicellulose compounds (Vesterdal et al, 2008 ; Adams et al, 2019 ). In contrast, linked to evergreen plots, we found bacterial indicator genera like Inquilinus, Acidocella , or Alicyclobacillus that could be adapted to typically acidic soils (Jung et al, 2011 ; Okamoto et al, 2017 ), and Longimycelium and Actinomadura (Zakharova et al, 2003 ; Xia et al, 2013 ), characterized by slow growth and efficient use of recalcitrant carbon resources and secondary metabolite production, which are traits rather associated with K-strategists and environments where resource supply rates are lower (Ho et al, 2017 ). Concerning fungi, interestingly, our RF revealed that free-living unicellular fungi were indicators of evergreen forest plots.…”

Section: Discussionmentioning

confidence: 88%

Effects of Tree Composition and Soil Depth on Structure and Functionality of Belowground Microbial Communities in Temperate European Forests

Prada-Salcedo

Heintz‐Buschart

et al. 2022

Front. Microbiol.

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Depending on their tree species composition, forests recruit different soil microbial communities. Likewise, the vertical nutrient gradient along soil profiles impacts these communities and their activities. In forest soils, bacteria and fungi commonly compete, coexist, and interact, which is challenging for understanding the complex mechanisms behind microbial structuring. Using amplicon sequencing, we analyzed bacterial and fungal diversity in relation to forest composition and soil depth. Moreover, employing random forest models, we identified microbial indicator taxa of forest plots composed of either deciduous or evergreen trees, or their mixtures, as well as of three soil depths. We expected that forest composition and soil depth affect bacterial and fungal diversity and community structure differently. Indeed, relative abundances of microbial communities changed more across soil depths than in relation to forest composition. The microbial Shannon diversity was particularly affected by soil depth and by the proportion of evergreen trees. Our results also reflected that bacterial communities are primarily shaped by soil depth, while fungi were influenced by forest tree species composition. An increasing proportion of evergreen trees did not provoke differences in main bacterial metabolic functions, e.g., carbon fixation, degradation, or photosynthesis. However, significant responses related to specialized bacterial metabolisms were detected. Saprotrophic, arbuscular mycorrhizal, and plant pathogenic fungi were related to the proportion of evergreen trees, particularly in topsoil. Prominent microbial indicator taxa in the deciduous forests were characterized to be r-strategists, whereas K-strategists dominated evergreen plots. Considering simultaneously forest composition and soil depth to unravel differences in microbial communities, metabolic pathways and functional guilds have the potential to enlighten mechanisms that maintain forest soil functionality and provide resistance against disturbances.

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Section: Discussionmentioning

confidence: 88%

Effects of Tree Composition and Soil Depth on Structure and Functionality of Belowground Microbial Communities in Temperate European Forests

Prada-Salcedo

Heintz‐Buschart

et al. 2022

Front. Microbiol.

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“…According to recent research, there is compelling evidence indicating that uncommon actinomycetes, such as those from the less explored Antarctic possess significant promise in the production of novel antibiotics (Lazzarini et al, 2001). According to reports, novel antibiotics with specialised properties have been discovered from actinomycetes residing under unique environmental circumstances (Zakharova et al, 2003).…”

Section: Resultsmentioning

confidence: 99%

Antimicrobial activity of two Antarctic Streptomyces strains

ZiAng, C.,

Peng, T. C.,

Yin, F. H.

et al. 2023

MJM

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Aims:The search for new antibiotics is an ongoing effort and has expanded to pristine niche areas in the Antarctic in recent years due to the emergence of multi-drug resistant pathogens that outpaced the discovery of new antibiotics. We have recently isolated two new actinomycetes strains, INACH3013a and INACH3013b, which displayed antimicrobial properties from soil samples collected from Ardley Island, Antarctica. Hence, an investigation was carried out to identify them and to characterise the antimicrobial compounds produced. Methodology and results: Strains, INACH3013a and INACH3013b were identified based on their 16S rDNA sequence alignment to those in the GenBank. The results showed that strain INACH3013a was closest to Streptomyces spp. while strain INACH3013b was closest to Streptomyces corallincola and Streptomyces bullii. The extracellular compounds they produced were extracted using various solvents and the extracted compounds were tested against the test pathogens. The dichloromethane extracts from strains, INACH3013a and INACH3013b inhibited mainly Gram-positive pathogens that include Listeria monocytogenes, Staphylococcus aureus, Staphylococcus haemolyticus, Staphylococcus equorum, Bacillus cereus K3 and Enterococcus faecalis while extracts from strain INACH3013b also inhibited a Gram-negative pathogen, Klebsiella pneumonia 14x. Predominantly non-polar constituents seem responsible for antibacterial effects, with dichloromethane extracts proving most efficacious, followed by chloroform and ethyl acetate. Conclusion, significance and impact of study: The research highlights the potential of Streptomyces spp. INACH3013a and INACH3013b as a source of potential novel antibiotics. This research explores Antarctic Streptomyces strains' antimicrobial capabilities, enabling the potential for the discovery of novel antibiotics and revealing how these compounds may have helped them to compete and survive in nutrient-deficient Antarctic niches.

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“…Tenfold dilutions of the Atacama Desert soil samples were used to inoculate starch-casein agar (SCA; Küster and Williams, 1964 ), humic acid-vitamin agar (HA; Hayakawa and Nonomura, 1987 ), Gauze’s no. 1 agar (G; Zakharova et al, 2003 ) and R2A agar (Becto-Dickinson, United State) plates which were incubated at 28°C for 21 days. The pH of the Atacama soil samples ranged from 6.6 to 7.6, the organic matter content from 1.7% to 3.7%, the moisture content was zero %.…”

Section: Methodsmentioning

confidence: 99%

Generation of a high quality library of bioactive filamentous actinomycetes from extreme biomes using a culture-based bioprospecting strategy

2023

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IntroductionFilamentous actinomycetes, notably members of the genus Streptomyces, remain a rich source of new specialized metabolites, especially antibiotics. In addition, they are also a valuable source of anticancer and biocontrol agents, biofertilizers, enzymes, immunosuppressive drugs and other biologically active compounds. The new natural products needed for such purposes are now being sought from extreme habitats where harsh environmental conditions select for novel strains with distinctive features, notably an ability to produce specialized metabolites of biotechnological value.MethodsA culture-based bioprospecting strategy was used to isolate and screen filamentous actinomycetes from three poorly studied extreme biomes. Actinomycetes representing different colony types growing on selective media inoculated with environmental suspensions prepared from high-altitude, hyper-arid Atacama Desert soils, a saline soil from India and from a Polish pine forest soil were assigned to taxonomically predictive groups based on characteristic pigments formed on oatmeal agar. One hundred and fifteen representatives of the colour-groups were identified based on 16S rRNA gene sequences to determine whether they belonged to validly named or to putatively novel species. The antimicrobial activity of these isolates was determined using a standard plate assay. They were also tested for their capacity to produce hydrolytic enzymes and compounds known to promote plant growth while representative strains from the pine forest sites were examined to determine their ability to inhibit the growth of fungal and oomycete plant pathogens.ResultsComparative 16S rRNA gene sequencing analyses on isolates representing the colour-groups and their immediate phylogenetic neighbours showed that most belonged to either rare or novel species that belong to twelve genera. Representative isolates from the three extreme biomes showed different patterns of taxonomic diversity and characteristic bioactivity profiles. Many of the isolates produced bioactive compounds that inhibited the growth of one or more strains from a panel of nine wild strains in standard antimicrobial assays and are known to promote plant growth. Actinomycetes from the litter and mineral horizons of the pine forest, including acidotolerant and acidophilic strains belonging to the genera Actinacidiphila,Streptacidiphilus and Streptomyces, showed a remarkable ability to inhibit the growth of diverse fungal and oomycete plant pathogens.DiscussionIt can be concluded that selective isolation and characterization of dereplicated filamentous actinomyctes from several extreme biomes is a practical way of generating high quality actinomycete strain libraries for agricultural, industrial and medical biotechnology.

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Cited by 27 publications

References 7 publications

Effects of Tree Composition and Soil Depth on Structure and Functionality of Belowground Microbial Communities in Temperate European Forests

Effects of Tree Composition and Soil Depth on Structure and Functionality of Belowground Microbial Communities in Temperate European Forests

Antimicrobial activity of two Antarctic Streptomyces strains

Generation of a high quality library of bioactive filamentous actinomycetes from extreme biomes using a culture-based bioprospecting strategy

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