Thermophilic and alkaliphilic Actinobacteria: biology and potential applications

Shivlata, L.; Satyanarayana, T.

doi:10.3389/fmicb.2015.01014

Cited by 198 publications

(128 citation statements)

References 278 publications

(243 reference statements)

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“…Considering the tolerance to high temperature, several actinobacteria strains fit into the facultative thermophiles group which may indicate that hydrothermal conditions quite common in the lakes (6‐31) and high sun irradiation regime of soils selected strains able to grow under higher temperatures. Thermophilic and thermotolerant actinobacteria were found in diverse niches such as moldy hay, self‐heating plant residues, cereal grains, sugar cane bagasse, decaying vegetable materials, soils, compost heaps, sea sediment and hot springs (for a review, see ), but this is the first time that thermophilic actinobacteria were described in stromatolites. In coincidence with our findings, the complex of thermotolerant actinomycetes described for the Mongolia desert steppe included representatives of Streptomyces and Micromonospora .…”

Section: Discussionmentioning

confidence: 99%

UV‐Resistant Actinobacteria from High‐Altitude Andean Lakes: Isolation, Characterization and Antagonistic Activities

Rasuk

Ferrer

Kurth

et al. 2017

Photochem & Photobiology

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Polyextremophiles are present in a wide variety of extreme environments in which they must overcome various hostile conditions simultaneously such as high UVB radiation, extreme pHs and temperatures, elevated salt and heavy-metal concentration, low-oxygen pressure and scarce nutrients. High-altitude Andean lakes (HAALs; between 2000 and 4000 m) are one example of these kinds of ecosystems suffering from the highest total solar and UVB radiation on Earth where an abundant and diverse polyextremophilic microbiota was reported. In this work, we performed the first extensive isolation of UV-resistant actinobacteria from soils, water, sediments and modern stromatolites at HAALs. Based on the 16S rRNA sequence, the strains were identified as members of the genera Streptomyces, Micrococcus, Nesterenkonia, Rhodococcus, Microbacterium, Kocuria, Arthrobacter, Micromonospora, Blastococcus, Citrococcus and Brevibacterium. Most isolates displayed resistance to multiple environmental stress factors confirming their polyextremophilic nature and were able to produce effective antimicrobial compounds. HAALs constitute a largely unexplored repository of UV-resistant actinobacteria, with high potential for the biodiscovery of novel natural products.

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Section: Discussionmentioning

confidence: 99%

UV‐Resistant Actinobacteria from High‐Altitude Andean Lakes: Isolation, Characterization and Antagonistic Activities

Rasuk

Ferrer

Kurth

et al. 2017

Photochem & Photobiology

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“…This allows actinobacteria to adapt and colonize different types of environments (Shivlata and Satyanarayana, 2015).…”

Section: Discussionmentioning

confidence: 99%

Characterization of actinobacteria from the semiarid region, and their antagonistic effect on strains of rhizobia

Lima¹,

Martins²,

Siqueira³

et al. 2017

Afr. J. Biotechnol.

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The actinobacteria are the most abundant bacterial group in the soil, where they present different characteristics and antagonistic effects on other microorganisms. The objectives of this study were to characterize and evaluate the antagonistic effect of actinobacteria from the semiarid region on rhizobia from the same climatic region. Tests were performed to observe chromogenic and micro-morphological characteristics, tolerance to pH levels of melanin production, and use of carbon sources. This occurred due to the use of modified CDA culture media and basal medium supplemented with specific carbon sources, as well as the use of Ral color chat to observe the colonies. The in vitro antagonism on rhizobia was evaluated in yeast malt agar (YMA) culture medium for the observation of inhibition halo by actinobacteria. We observed different characteristics in relation to the color of aerial mycelium and reverse pigments; tolerance to media with acid and alkaline pH; and production of melanoid pigment occurred only in three strains. The morphological characteristics were described for genera Streptomyces and Saccharothrix, later confirmed by molecular sequencing. These genera were generalists in use of carbon sources, showing their physiological versatility. Regarding antagonism, nine strains of the genus Streptomyces were able to inhibit in vitro strains of Rhizobium tropici and Bradyrhizobium yuanmingense also coming from semiarid soils. The antagonism between actinobacteria and rhizobia can directly affect the symbiosis between nitrogen-fixing bacteria and leguminous plants. These results are pioneering in observing antagonism of these species of rhizobia under the climate condition of the semiarid region, and may contribute to agricultural biotechnology.

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“…More interestingly however, the Bradyrhizobiaceae ( Bosea ) and Microbacteriaceae ( Galbitalea ) are bio-degraders capable of producing hydrolytic enzymes such as chitinase, cellulase, glucanase, protease, etc. (57,63). As these are positively correlated with fecundity and host fitness, it suggests that increased network density and number of degradation pathways may contribute by providing essential nutrients from more available substrates (64).…”

Section: Discussionmentioning

confidence: 99%

Disparate effects of antibiotic-induced microbiome change and enhanced fitness inDaphnia magna

Motiei

Brindefalk

Ogonowski

et al. 2019

Preprint

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13It is a common view that an organism's microbiota has a profound influence on host fitness; 14 however, supporting evidence is lacking in many organisms. We manipulated the gut 15 microbiome of Daphnia magna by chronic exposure to different concentrations of the 16 antibiotic Ciprofloxacin (0.01 -1 mg L -1 ), and evaluated whether this affected the animals' 17 fitness and antioxidant capacity. In line with our expectations, antibiotic exposure altered the 18 microbiome in a concentration-dependent manner. However, contrary to these expectations, 19 the reduced diversity of gut bacteria was not associated with any fitness detriment. Moreover, 20 the growth-related parameters correlated negatively with diversity indices; and, in the 21 daphnids exposed to the lowest ciprofloxacin concentrations, the antioxidant capacity, 22 growth, and fecundity were even higher than in control animals. These findings suggest that 23 ciprofloxacin exerts direct stimulatory effects on growth and reproduction in Daphnia, while 24 microbiome-mediated effects are of lesser importance. Thus, although microbiome profiling 25 of Daphnia may be a sensitive tool to identify early effects of antibiotic exposure, 26 disentangling direct and microbiome-mediated effects on host fitness is not straightforward. 27 68 sequencing (22 , 23). Regardless of the sequencing platform, origin of specimens, and culture 69 conditions, the core microbiome appears relatively stable, mainly comprised of 70 Betaproteobacteria, Gammaproteobacteria and facultative anaerobic Bacteroidetes species. 71At the genus level, Limnohabitans has been reported as one of the most stable and dominant 72 members in Daphnia gut, and variations in its abundance have been tied to the animal 73 fecundity (22). Although some studies have addressed the dependence of Daphnia on its 74 microbiota (9) and some short-term effects on fitness following exposure to antibiotics have 75 been observed in Daphnia magna (25, 13), the relationship between microflora perturbation 76 and host fitness is still unclear, as is the involvement and modulating role of antioxidants in 77 these relationships. 78In this study, the relationship between antibiotic-mediated gut microbiome modulation and 79 host fitness were addressed experimentally using a model cladoceran Daphnia magna. We 80 monitored changes in the gut microbiome, host longevity, growth, and reproduction, as well 81 as antioxidant levels in the exposed animals following ciprofloxacin exposure. We 82 hypothesized that the diversity and abundance of the gut-associated microflora would 83 decrease with increasing concentration of antibiotics. Furthermore, we expected longer 84 exposure time and higher antibiotic concentrations to have negative effects on somatic 85 growth, reproductive output, and antioxidant capacity. These reductions we expected would 86 be due to reduced bacterial diversity in particular, and to some extent, an altered community 87 composition. These hypotheses were tested by combining (1) long-term (21 d) exposure...

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Thermophilic and alkaliphilic Actinobacteria: biology and potential applications

Cited by 198 publications

References 278 publications

UV‐Resistant Actinobacteria from High‐Altitude Andean Lakes: Isolation, Characterization and Antagonistic Activities

UV‐Resistant Actinobacteria from High‐Altitude Andean Lakes: Isolation, Characterization and Antagonistic Activities

Characterization of actinobacteria from the semiarid region, and their antagonistic effect on strains of rhizobia

Disparate effects of antibiotic-induced microbiome change and enhanced fitness inDaphnia magna

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