Abstract:Thermoleptolyngbya is a genus of non-heterocystous cyanobacteria that are typical inhabitants of hot spring microbial mats. These filamentous cyanobacteria are capable of nitrogen fixation. In this study, we examined the genome sequences of five publicly available Thermoleptolyngbya strains to explore their nitrogen fixation gene cluster. Analysis of the nitrogen-fixation clusters in these extremophilic strains revealed that the cluster is located in a single locus in Thermoleptolyngbyace. The average nucleoti… Show more
“…Physiological assessment of the strain was performed using BG-11 medium free of an essential nutrient (nitrogen or sulfur) supplemented with 17 mM NaNO 2 , 85 mM NaNO 3 , 10 mM Na 2 SO 4 , and 10 mM NaHSO 3 . The nitrogen fixation capacity during 72 h was performed using the methodology described by Li et al (2021) .…”
Section: Methodsmentioning
confidence: 99%
“…Thermophilic cyanobacteria are photoautotrophic prokaryotes that inhabit inhospitable niches, such as hot springs and other thermal environments. These thermophiles are essentially primary producers of the geothermal ecosystems with substantial ecological importance ( Esteves-Ferreira et al, 2018 ; Li et al, 2021 ). Besides, thermophilic cyanobacteria and their secondary metabolites have shown some potentials for biotechnological applications, including biosynthesis of thermostable metabolites and carbon valorisation vehicles ( Patel et al, 2019 ).…”
Thermal environments are an important reservoir of thermophiles with significant ecological and biotechnological potentials. However, thermophilic isolates remain largely unrecovered from their habitats and are rarely systematically identified. In this study, we characterized using polyphasic approaches a thermophilic strain, PKUAC-SCTAE412 (E412 hereafter), recovered from Lotus Lake hot spring based in Ganzi prefecture, China. The results of 16S rRNA/16S-23S ITS phylogenies, secondary structure, and morphology comparison strongly supported that strain E412 represent a novel genus within Leptolyngbyaceae. This delineation was further confirmed by genome-based analyses [phylogenomic inference, average nucleotide/amino-acid identity, and the percentages of conserved proteins (POCP)]. Based on the botanical code, the isolate is herein delineated as Leptothermofonsia sichuanensis gen. sp. nov, a genus adjacent to recently delineated Kovacikia and Stenomitos. In addition, we successfully obtained the first complete genome of this new genus. Genomic analysis revealed its adaptations to the adverse hot spring environment and extensive molecular components related to mobile genetic elements, photosynthesis, and nitrogen metabolism. Moreover, the strain was capable of modifying the composition of its light-harvesting apparatus depending on the wavelength and photoperiod, showing chromatic adaptation capacity characteristic for T1 and T2 pigmentation types. Other physiological studies showed the strain’s ability to utilize sodium bicarbonate and various sulfur compounds. The strain was also shown to be diazotrophic. Interestingly, 24.6% of annotated protein-coding genes in the E412 genome were identified as putatively acquired, hypothesizing that a large number of genes acquired through HGT might contribute to the genome expansion and habitat adaptation of those thermophilic strains. Most the HGT candidates (69.4%) were categorized as metabolic functions as suggested by the KEGG analysis. Overall, the complete genome of strain E412 provides the first insight into the genomic feature of the genus Leptothermofonsia and lays the foundation for future global ecogenomic and geogenomic studies.
“…Physiological assessment of the strain was performed using BG-11 medium free of an essential nutrient (nitrogen or sulfur) supplemented with 17 mM NaNO 2 , 85 mM NaNO 3 , 10 mM Na 2 SO 4 , and 10 mM NaHSO 3 . The nitrogen fixation capacity during 72 h was performed using the methodology described by Li et al (2021) .…”
Section: Methodsmentioning
confidence: 99%
“…Thermophilic cyanobacteria are photoautotrophic prokaryotes that inhabit inhospitable niches, such as hot springs and other thermal environments. These thermophiles are essentially primary producers of the geothermal ecosystems with substantial ecological importance ( Esteves-Ferreira et al, 2018 ; Li et al, 2021 ). Besides, thermophilic cyanobacteria and their secondary metabolites have shown some potentials for biotechnological applications, including biosynthesis of thermostable metabolites and carbon valorisation vehicles ( Patel et al, 2019 ).…”
Thermal environments are an important reservoir of thermophiles with significant ecological and biotechnological potentials. However, thermophilic isolates remain largely unrecovered from their habitats and are rarely systematically identified. In this study, we characterized using polyphasic approaches a thermophilic strain, PKUAC-SCTAE412 (E412 hereafter), recovered from Lotus Lake hot spring based in Ganzi prefecture, China. The results of 16S rRNA/16S-23S ITS phylogenies, secondary structure, and morphology comparison strongly supported that strain E412 represent a novel genus within Leptolyngbyaceae. This delineation was further confirmed by genome-based analyses [phylogenomic inference, average nucleotide/amino-acid identity, and the percentages of conserved proteins (POCP)]. Based on the botanical code, the isolate is herein delineated as Leptothermofonsia sichuanensis gen. sp. nov, a genus adjacent to recently delineated Kovacikia and Stenomitos. In addition, we successfully obtained the first complete genome of this new genus. Genomic analysis revealed its adaptations to the adverse hot spring environment and extensive molecular components related to mobile genetic elements, photosynthesis, and nitrogen metabolism. Moreover, the strain was capable of modifying the composition of its light-harvesting apparatus depending on the wavelength and photoperiod, showing chromatic adaptation capacity characteristic for T1 and T2 pigmentation types. Other physiological studies showed the strain’s ability to utilize sodium bicarbonate and various sulfur compounds. The strain was also shown to be diazotrophic. Interestingly, 24.6% of annotated protein-coding genes in the E412 genome were identified as putatively acquired, hypothesizing that a large number of genes acquired through HGT might contribute to the genome expansion and habitat adaptation of those thermophilic strains. Most the HGT candidates (69.4%) were categorized as metabolic functions as suggested by the KEGG analysis. Overall, the complete genome of strain E412 provides the first insight into the genomic feature of the genus Leptothermofonsia and lays the foundation for future global ecogenomic and geogenomic studies.
“…Moreover, the total nitrogen content of the former was higher than that of the latter, which might result from more core bacteria associated with N 2 fixation in the CSL treatment. This was also intrinsic to the higher total nitrogen content in the CSL treatment [ 46 – 48 ]. Fig.…”
Background
Carbon and nitrogen are essential energy and nutrient substances in the composting process. Corn steep liquor (CSL) is rich in soluble carbon and nitrogen nutrients and active substances and is widely used in the biological industry. Nonetheless, limited research has been done on the effect of CSL on composting. This work firstly reveals the effect of adding CSL to bacterial community composition and carbon and nitrogen conversion during composting. This study provides the choice of auxiliary materials for the spent mushroom substrate compost (SMS) and some novel knowledge about the effect of bacterial community on C and N cycling during composting of SMS and CSL. Two treatments were set up in the experiment: 100% spent mushroom substrate (SMS) as CK and SMS + 0.5% CSL (v/v) as CP.
Results
The results showed that the addition of CSL enhanced the initial carbon and nitrogen content of the compost, altered the bacterial community structure, and increased the bacterial diversity and relative abundance, which might be beneficial to the conversion and retention of carbon and nitrogen in the composting process. In this paper, network analysis was used to screen the core bacteria involved in carbon and nitrogen conversion. In the CP network, the core bacteria were divided into two categories, synthesizing and degrading bacteria, and there were more synthesizing bacteria than degrading bacteria, so the degradation and synthesis of organic matter were carried out simultaneously, while only degrading bacteria were found in the CK network. Functional prediction by Faprotax identified 53 groups of functional bacteria, among which 20 (76.68% abundance) and 14 (13.15% abundance) groups of functional bacteria were related to carbon and nitrogen conversion, respectively. Adding CSL stimulated the compensatory effect of core and functional bacteria, enhanced the carbon and nitrogen transformation ability, stimulated the activity of low-abundance bacteria, and reduced the competitive relationship between the bacterial groups. This may be why the addition of CSL accelerated the organic matter degradation and increased carbon and nitrogen preservation.
Conclusions
These findings indicate that the addition of CSL promoted the cycling and preservation of carbon and nitrogen in the SMS composts, and the addition of CSL to the compost may be an effective way to dispose of agricultural waste.
“…Thermoleptolyngbya sp. B121 (Li et al., 2021), was isolated from the hot spring in Ganzi prefecture. Leptothermofonsia (Tang et al., 2022), a novel genus within the family Leptolyngbyaceae, was isolated from Lotus Lake hot springs situated in Ganzi prefecture.…”
Section: Discussionmentioning
confidence: 99%
“…Several studies have shown the beneficial effects of free‐living soil cyanobacteria in such arid regions, including increased soil stability and improved soil fertility (e.g., Belnap & Gardner, 1993; Evans & Johansen, 1999; Muhlsteinova et al., 2014). Thermophilic cyanobacteria inhabit inhospitable niches, such as hot springs, and these thermophilic cyanobacteria are basically the main primary producers of the geothermal ecosystem and have important ecological significance (Esteves‐Ferreira et al., 2018; Li et al., 2021; Tang et al., 2022). However, despite the ecological importance of cyanobacteria in these habitats, we are still far from fully understanding the diversity of cyanobacteria in arid or semi‐arid soils and in hot springs.…”
To increase the understanding of simple thin filamentous cyanobacteria in harsh environmental areas, we previously isolated and identified four strains (XN101, XN102, GS121, NX122) from desert soils and hot spring in China. As a result, two new Oculatellacean genera of these four strains, Gansulinema gen. nov. and Komarkovaeasiopsis gen. nov., are described based on a polyphasic approach. The ultrastructure of these strains showed a similar arrangement of peripheral thylakoids with three to four parallel layers, indicating that they belonged to the orders Nodosilineales, Oculatellales, or Leptolyngbyales. In the 16S rRNA gene phylogeny, two sequences of the Gansulinema strains and the two sequences of the Komarkovaeasiopsis strains formed two independent and robust clusters, within the order Oculatellales. The 16S rRNA gene sequences of strains of Komarkovaeasiopsis and Gansulinema showed low identity to each other (≤93.2%) and to other sequences of the Oculatellacean genera (≤94.5% and ≤93.3%, respectively). Furthermore, the 16S–23S internal transcribed spacer rRNA region secondary structures of strains of Komarkovaeasiopsis and Gansulinema were not consistent with all existing descriptions of Oculatellacean taxa. These data suggest that cyanobacterial communities are rich sources of new taxa in under‐exploited areas, such as desert soils and hot spring in China.
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