The genome of a vestimentiferan tubeworm (Ridgeia piscesae) provides insights into its adaptation to a deep-sea environment.

BACKGROUND: Vestimentifera (Polychaeta, Siboglinidae) is a taxon of deep-sea worm-like animals living in deep-sea hydrothermal vents, cold seeps, and organic falls. The morphology and lifespan of Ridgeia piscesae, which is the only vestimentiferan tubeworm species found in the hydrothermal vents on the Juan de Fuca Ridge, vary greatly according to endemic environment. Recent analyses have revealed the genomic basis of adaptation in three vent- and seep-dwelling vestimentiferan tubeworms. However, the evolutionary history and mechanism of adaptation in R. piscesae, a unique species in the family Siboglinidae, remain to be investigated. RESULT: We assembled a draft genome of R. piscesae collected at the Cathedral vent of the Juan de Fuca Ridge. Comparative genomic analysis showed that vent-dwelling tubeworms with a higher growth rate had smaller genome sizes than seep-dwelling tubeworms that grew much slower. A strong positive correlation between repeat content and genome size but not intron size and the number of protein-coding genes was identified in these deep-sea tubeworm species. Evolutionary analysis revealed that Ridgeia pachyptila and R. piscesae, the two tubeworm species that are endemic to hydrothermal vents of the eastern Pacific, started to diverge between 28.5 and 35 million years ago. Four genes involved in cell proliferation were found to be subject to positive selection in the genome of R. piscesae. CONCLUSION: Ridgeia pachyptila and R. piscesae started to diverge after the formation of the Gorda/Juan de Fuca/Explorer ridge systems and the East Pacific Rise. The high growth rates of vent-dwelling tubeworms might be derived from their small genome sizes. Cell proliferation is important for regulating the growth rate in R. piscesae.

Isolation, characterization, and comparative genomic analysis of vB_BviS-A10Y, a novel bacteriophage from mangrove sediments.

Mangrove is among the most carbon-rich biomes on earth, and viruses are believed to play a significant role in modulating local and global carbon cycling. However, few viruses have been isolated from mangrove sediments to date. Here, we report the isolation of a novel Bacillus phage (named phage vB_BviS-A10Y) from mangrove sediments. Phage vB_BviS-A10Y has a hexameric head with a diameter of ~ 79.22 nm and a tail with a length of ~ 548.56 nm, which are typical features of siphophages. vB_BviS-A10Y initiated host lysis at 3.5 h postinfection with a burst size of 25 plaque-forming units (PFU)/cell. The genome of phage vB_BviS-A10Y is 162,435 bp long with 225 predicted genes, and the GC content is 34.03%. A comparison of the whole genome sequence of phage vB_BviS-A10Y with those of other phages from the NCBI viral genome database showed that phage vB_BviS-A10Y has the highest similarity (73.7% identity with 33% coverage) to Bacillus phage PBC2. Interestingly, abundant auxiliary metabolic genes (AMGs) were identified in the vB_BviS-A10Y genome. The presence of a ß-1,3-glucosyltransferase gene in the phage genome supported our previous hypothesis that mangrove viruses may manipulate carbon cycling directly through their encoded carbohydrate-active enzyme (CAZyme) genes. Therefore, our study will contribute to a better understanding of the diversity and potential roles of viruses in mangrove ecosystems.

The importance of conditionally rare taxa for the assembly and interaction of fungal communities in mangrove sediments.

The fungal communities provide the nutrients and drive the cycles of elements in nature, and the rare fungal taxa are proved to be crucial for these communities in many environments. However, the ecological functions of rare taxa for the fungal communities in mangrove ecosystems are poorly assessed until now. This work aims to reveal the importance of rare taxa for the assembly of fungal communities in mangrove sediments by using the amplicon sequencing analysis of different spatiotemporal samples collected from Sanya mangroves, China. The results showed that Ascomycota and Basidiomycota were the dominant phyla in the conditionally rare taxa (CRT). The fungal communities possessed outstanding stability against the spatiotemporal variation and most collected environmental factors. The CRT possessed narrower niches and were more affected by the environmental variables than the abundant taxa. The current work demonstrated that the CRT had significantly higher relative abundances, degrees (the number of adjacent edges), clustering coefficients, and closeness centralities in the top 8 modules of the co-occurrence network (p < 0.05), indicating the important role of the CRT for the interaction of fungal communities in mangrove sediments. These findings indicate the importance of the CRT for the fungal community structures in mangrove sediments, and would deepen our understanding of dynamic functions of mangrove fungi, thereby facilitating the management, utilization, and protection of mangrove ecosystems. KEY POINTS: • Fungal communities in mangrove sediments are stable against environment variations. • The conditionally rare taxa (CRT) possessed narrower niches than the abundant fungal taxa. • The CRT are central for the co-occurrence network and interaction of fungal communities.

Neoagaro-Oligosaccharides Ameliorate Chronic Restraint Stress-Induced Depression by Increasing 5-HT and BDNF in the Brain and Remodeling the Gut Microbiota of Mice.

Neoagaro-oligosaccharides (NAOs) belong to the algae oligosaccharides. NAOs have been found to have diverse biological activities. However, the effects of NAOs on depression and their underlying mechanism have not been thoroughly studied. A chronic restraint stress (CRS)-induced C57BL/6J mouse model was used to assess the antidepressant effects of NAOs. Anxiety and depression behaviors were assessed by open field tests (OFT) and forced swimming tests (FST), while interleukin 18 (IL-18), 5-hydroxytryptamine (5-HT) and brain-derived neurotrophic factor (BDNF) were the molecular biomarkers of depression. Fecal microbiota transplantation (FMT) was performed. The results showed that NAO treatment significantly improved the body weight of depressed mice and reduced the central area time in the OFT and immobility time in the FST. NAO treatment decreased the levels of IL-18 in the serum and increased the levels of 5-HT in the serum and whole brain and of BDNF in the whole brain. NAO treatment mitigated the gut microbiota dysbiosis in the depressed mice and reversed the decreased levels of short-chain fatty acids (SCFAs) in the cecum of the depressed mice. FMT indicated that the gut microbiota is, indeed, linked to depression, which was reflected in the changes in weight gain and behaviors. In a word, NAOs effectively reversed the CRS-induced mice model of depression, which depended on the changes in the gut microbiota and SCFAs, as well as its modulation of 5-HT and BDNF.

Agarose-Degrading Characteristics of a Deep-Sea Bacterium Vibrio Natriegens WPAGA4 and Its Cold-Adapted GH50 Agarase Aga3420.

Up until now, the characterizations of GH50 agarases from Vibrio species have rarely been reported compared to GH16 agarases. In this study, a deep-sea strain, WPAGA4, was isolated and identified as Vibrio natriegens due to the maximum similarity of its 16S rRNA gene sequence, the values of its average nucleotide identity, and through digital DNA-DNA hybridization. Two circular chromosomes in V. natriegens WPAGA4 were assembled. A total of 4561 coding genes, 37 rRNA, 131 tRNA, and 59 other non-coding RNA genes were predicted in the genome of V. natriegens WPAGA4. An agarase gene belonging to the GH50 family was annotated in the genome sequence and expressed in E. coli cells. The optimum temperature and pH of the recombinant Aga3420 (rAga3420) were 40 °C and 7.0, respectively. Neoagarobiose (NA2) was the only product during the degradation process of agarose by rAga3420. rAga3420 had a favorable stability following incubation at 10-30 °C for 50 min. The Km, Vmax, and kcat values of rAga3420 were 2.8 mg/mL, 78.1 U/mg, and 376.9 s-1, respectively. rAga3420 displayed cold-adapted properties as 59.7% and 41.2% of the relative activity remained at 10 3 °C and 0 °C, respectively. This property ensured V. natriegens WPAGA4 could degrade and metabolize the agarose in cold deep-sea environments and enables rAga3420 to be an appropriate industrial enzyme for NA2 production, with industrial potential in medical and cosmetic fields.

Vibrio ziniensis sp. nov., isolated from mangrove sediments.

A novel Gram-staining-negative, catalase- and oxidase-positive, facultatively anaerobic and rod-shaped motile bacterial strain, designated as ZWAL4003T, was isolated from mangrove sediments of the Zini Mangrove Forest, Zhangzhou City, PR China. Phylogenetic analysis based on its 16S rRNA gene sequence indicated that ZWAL4003T was grouped into a separated branch with Vibrio plantisponsor MSSRF60T (97.38% nucleotide sequence identity) and Vibrio diazotrophicus NBRC 103148T (97.27%). The major cellular fatty acids were C14 : 0 (12.6%), C16 : 0 (17.6%), and summed feature 3 (C16 : 1ω6c /C16 : 1 ω7c, 45.6%). Its genome had a length of 4650556 bp with 42.8% DNA G+C content, and contained genes involved in the biosynthesis of bacteriocin, ß-lactone, resorcinol, N-acyl amino acid, and arylpolyene. The in silico DNA-DNA hybridization and average nucleotide identity values for whole-genome sequence comparisons between ZWAL4003T and V. plantisponsor LMG 24470T were clearly below the thresholds used for the delineation of a novel species. The morphological and chemotaxonomic characteristics and the genotypic data of ZWAL4003T indicated that it represented a novel species of the genus Vibrio. Its proposed name is Vibrio ziniensis sp. nov., and the type strain is ZWAL4003T (=KCTC 72971T=MCCC 1A17474T).

Expression and Characterization of a Novel Cold-Adapted and Stable ß-Agarase Gene agaW1540 from the Deep-Sea Bacterium Shewanella sp. WPAGA9.

The neoagaro-oligosaccharides, degraded from agarose by agarases, are important natural substances with many bioactivities. In this study, a novel agarase gene, agaW1540, from the genome of a deep-sea bacterium Shewanella sp. WPAGA9, was expressed, and the recombinant AgaW1540 (rAgaW1540) displayed the maximum activity under the optimal pH and temperature of 7.0 and 35 °C, respectively. rAgaW1540 retained 85.4% of its maximum activity at 0 °C and retained more than 92% of its maximum activity at the temperature range of 20-40 °C and the pH range of 4.0-9.0, respectively, indicating its extensive working temperature and pH values. The activity of rAgaW1540 was dramatically suppressed by Cu2+ and Zn2+, whereas Fe2+ displayed an intensification of enzymatic activity. The Km and Vmax of rAgaW1540 for agarose degradation were 15.7 mg/mL and 23.4 U/mg, respectively. rAgaW1540 retained 94.7%, 97.9%, and 42.4% of its maximum activity after incubation at 20 °C, 25 °C, and 30 °C for 60 min, respectively. Thin-layer chromatography and ion chromatography analyses verified that rAgaW1540 is an endo-acting ß-agarase that degrades agarose into neoagarotetraose and neoagarohexaose as the main products. The wide variety of working conditions and stable activity at room temperatures make rAgaW1540an appropriate bio-tool for further industrial production of neoagaro-oligosaccharides.

The degradation activities for three seaweed polysaccharides of Shewanella sp. WPAGA9 isolated from deep-sea sediments.

Seaweed oligosaccharides possess great bioactivities. However, different microbial strains are required to degrade multiple polysaccharides due to their limited biodegradability, thereby increasing the cost and complexity of production. Shewanella sp. WPAGA9 was isolated from deep-sea sediments in this study. According to the genomic and biochemical analyses, the extracellular fermentation broth of WPAGA9 had versatile degradation abilities for three typical seaweed polysaccharides including agar, carrageenan, and alginate. The maximum enzyme activities of the extracellular fermentation broth of WPAGA9 were 71.63, 76.4, and 735.13 U/ml for the degradation of agar, alginate, and carrageenan, respectively. Moreover, multiple seaweed oligosaccharides can be produced by the extracellular fermentation broth of WPAGA9 under similar optimum conditions. Therefore, WPAGA9 can simultaneously degrade three types of seaweed polysaccharides under similar conditions, thereby greatly reducing the production cost of seaweed oligosaccharides. This finding indicates that Shewanella sp. WPAGA9 is an ideal biochemical tool for producing multiple active seaweed oligosaccharides at low costs and is also an important participant in the carbon cycle process of the deep-sea environment.

A novel deep-sea bacteriophage possesses features of Wbeta-like viruses and prophages.

As the most abundant biological entities, viruses are major players in marine ecosystems. However, our knowledge about virus-host interactions and viral ecology in the deep sea remains very limited. In this study, a novel bacteriophage (designated as phage BVE2) infecting Bacillus cereus group bacteria, was isolated from deep-sea sediments. Phage BVE2 caused host lysis within 1.5 h after infection. However, the presence of two integrase-encoding genes in the BVE2 genome suggested that BVE2 may also follow a temperate strategy. The genome of phage BVE2 is approximately 20 kb in length and is predicted to encode 28 proteins. Genomic and phylogenetic analysis suggested that BVE2 is a highly mosaic phage that has inherited genetic features from Wbeta-like viruses, B. cereus prophages, and its host, suggesting that frequent horizontal gene transfer events occurred during its evolution. This study will help to reveal the evolutionary history of Wbeta-like viruses and improve our understanding of viral diversity and virus-host interactions in the deep sea.

Properties and Applications of Extremozymes from Deep-Sea Extremophilic Microorganisms: A Mini Review.

The deep sea, which is defined as sea water below a depth of 1000 m, is one of the largest biomes on the Earth, and is recognised as an extreme environment due to its range of challenging physical parameters, such as pressure, salinity, temperature, chemicals and metals (such as hydrogen sulphide, copper and arsenic). For surviving in such extreme conditions, deep-sea extremophilic microorganisms employ a variety of adaptive strategies, such as the production of extremozymes, which exhibit outstanding thermal or cold adaptability, salt tolerance and/or pressure tolerance. Owing to their great stability, deep-sea extremozymes have numerous potential applications in a wide range of industries, such as the agricultural, food, chemical, pharmaceutical and biotechnological sectors. This enormous economic potential combined with recent advances in sampling and molecular and omics technologies has led to the emergence of research regarding deep-sea extremozymes and their primary applications in recent decades. In the present review, we introduced recent advances in research regarding deep-sea extremophiles and the enzymes they produce and discussed their potential industrial applications, with special emphasis on thermophilic, psychrophilic, halophilic and piezophilic enzymes.

Extracellular expression of agarase rAgaM1 in Bacillus subtilis and its ability for neoagaro-oligosaccharide production.

An agarase gene (agaM1) was cloned, expressed and characterized by using Escherichia coli as host strain, revealing the outstanding properties of recombinant AgaM1 (rAgaM1) in agarose degradation and neoagaro-oligosaccharides (NAs) production in our previous work. In current study, agaM1 was extracellularly expressed in Bacillus subtilis, and we aim to assess the ability of the supernatant of recombinant B. subtilis fermentation broth containing rAgaM1 to degrade agarose without protein purification, which would save the cost of purification and avoid the activity loss during purification. The pH and temperature optima for the supernatant were 7.0 and 50 °C, respectively. The supernatant containing rAgaM1 has outstanding stability against 40 °C and 50 °C. Besides, we detailedly studied the possible influence factors of rAgaM1 expression in the supernatant, including pH, temperature, isopropyl ß-D-thiogalactoside (IPTG) concentration, initial optical density at a wavelength of 600 nm (OD600 ), and induction time, and the optimum conditions for rAgaM1 expression by B. subtilis were confirmed. Moreover, the supernatant was able to produce NAs by using the Gracilaria lemaneiformis, whose cells were broken by autoclaving, as substrate, and a total of 1.41 µmol ml-1 of NA, including neoagarotetraose and neoagarohexaose, was produced after degradation for 48 h. This ability could save the cost of substrates in NA production, although the method requires a further study. Our results reveal that the NAs with great potential in food and pharmaceutical industries could be inexpensive to make by the supernatant containing rAgaM1 of B. subtilis fermentation broth in the foreseeable future.

Cloning, expression, and characterization of thermal-stable and pH-stable agarase from mangrove sediments.

AgaM1, a ß-agarase belonging to glycoside hydrolases family 16 (GH16), was cloned from the environmental DNA of mangrove sediments. The gene agaM1 is 2136 bp in length and encodes a protein of 712 amino acids. The properties of recombinant AgaM1 (rAgaM1) were studied using prokaryotic expression. The optimum temperature and pH were 50 °C and 7.0, respectively, and rAgaM1 exhibited a high adaptability to wide ranges of temperature and pH. A relatively high activity was retained at from 30 to 60 °C and from pH 6.0 to 9.0. Thermal stability was showed more than 70% relative activity after pre-incubation at 40 °C for 60 h. Outstanding pH stability were observed for rAgaM1 from pH 5.0 to 10.0 after pre-incubation for 60 h. Thin-layer chromatography revealed neoagarotetraose (NA4) and neoagarohexaose (NA6) were the end-products of rAgaM1-degraded agarose. Besides, rAgaM1 were found with a Km of 1.82 mg ml-1 and a Vm of 357.14 U mg-1 for agarose. The Km was smaller than those of most agarases reported previously. This discrepancy revealed the high affinity of rAgaM1 to agarose. Overall, the results indicated the potential of rAgaM1 in future industrial application.

Proposal of nine novel species of the Bacillus cereus group.

Nine novel Gram-stain-positive bacteria were investigated by a polyphasic taxonomic approach. Based on the analysis of 16S rRNA gene sequences, these strains belonged to the Bacillus cereus group, sharing over 97 % similarity with the known species of this group, and less than 95 % similarity with other species of the genus Bacillus. Multilocus sequence typing analysis showed that they formed nine robust and well-separated branches from the known species. The digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values between the nine strains were, respectively, below the 70 and 96 % threshold values for species definition, and between each strain and the known type strains of this group were also below the two threshold values. On the basis of the phenotypic and phylogenetic data, along with low dDDH and ANI values among these strains, these bacteria are assigned to the following nine novel species of the B. cereus group: Bacillus paranthracis sp. nov., type strain Mn5T (=MCCC 1A00395T=KCTC 33714T=LMG 28873T); Bacillus pacificus sp. nov., type strain EB422T (=MCCC 1A06182T=KCTC 33858T); Bacillus tropicus sp. nov., type strain N24T (=MCCC 1A01406T=KCTC 33711T=LMG 28874T); Bacillus albus sp. nov., type strain N35-10-2T (=MCCC 1A02146T=KCTC 33710T=LMG 28875T); Bacillus mobilis sp. nov., type strain 0711P9-1T (=MCCC 1A05942T=KCTC 33717T=LMG 28877T); Bacillus luti sp. nov., type strain TD41T (=MCCC 1A00359T=KCTC 33716T=LMG 28872T); Bacillus proteolyticus sp. nov., type strain TD42T (=MCCC 1A00365T=KCTC 33715T=LMG 28870T); Bacillus nitratireducens sp. nov., type strain 4049T (=MCCC 1A00732T=KCTC 33713T=LMG 28871T); and Bacillus paramycoides sp. nov., type strain NH24A2T (=MCCC 1A04098T=KCTC 33709T=LMG 28876T).

Shewanella mangrovi sp. nov., an acetaldehyde-degrading bacterium isolated from mangrove sediment.

A taxonomic study was carried out on strain YQH10T, which was isolated from mangrove sediment collected from Zhangzhou, China during the screening of acetaldehyde-degrading bacteria. Cells of strain YQH10T were Gram-stain-negative rods and pale brown-pigmented. Growth was observed at salinities from 0 to 11% and at temperatures from 4 to 42 °C. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain YQH10T is affiliated to the genus Shewanella, showing the highest similarity with Shewanella haliotis DW01T (95.7%) and other species of the genus Shewanella (91.4-95.6 %). The principal fatty acids were iso-C15 : 0 and C17 : 1ω8c. The major respiratory quinone was Q-8. The polar lipids comprised phosphatidylethanolamine and phosphatidylglycerol. The genomic DNA had a G+C content of 48.3 mol%. Strain YQH10T can completely degrade 0.02% (w/v) acetaldehyde on 2216E at 28 °C within 48 h. Based on these phenotypic and genotypic data, strain YQH10T represents a novel species of the genus Shewanella, for which the name Shewanella mangrovi sp. nov. is proposed. The type strain is YQH10T ( = MCCC 1A00830T = JCM 30121T).

Rhizobium marinum sp. nov., a malachite-green-tolerant bacterium isolated from seawater.

A motile, Gram-stain-negative, non-pigmented bacterial strain, designated MGL06T, was isolated from seawater of the South China Sea on selection medium containing 0.1 % (w/v) malachite green. Strain MGL06T showed highest 16S rRNA gene sequence similarity to Rhizobium vignae CCBAU 05176T (97.2 %), and shared 93.2-96.9 % with the type strains of other recognized Rhizobium species. Phylogenetic analyses based on 16S rRNA and housekeeping gene sequences showed that strain MGL06T belonged to the genus Rhizobium. Mean levels of DNA-DNA relatedness between strain MGL06T and R. vignae CCBAU 05176T, Rhizobium huautlense S02T and Rhizobium alkalisoli CCBAU 01393T were 20 ± 3, 18 ± 2 and 14 ± 3 %, respectively, indicating that strain MGL06T was distinct from them genetically. Strain MGL06T did not form nodules on three different legumes, and the nodD and nifH genes were also not detected by PCR or based on the draft genome sequence. Strain MGL06T contained Q-10 as the predominant ubiquinone. The major fatty acid was C18 : 1ω7c/C18 : 1ω6c with minor amounts of C19 : 0 cyclo ω8c, C16 : 0 and C18 : 1ω7c 11-methyl. Polar lipids of strain MGL06T included unknown glycolipids, phosphatidylcholine, aminolipid, phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol, an unknown polar lipid and aminophospholipid. Based on its phenotypic and genotypic data, strain MGL06T represents a novel species of the genus Rhizobium, for which the name Rhizobium marinum sp. nov. is proposed. The type strain is MGL06T ( = MCCC 1A00836T = JCM 30155T).

Expression and characterization of a thermostable penicillin G acylase from an environmental metagenomic library.

One clone (ACPGA001) exhibiting penicillin G acylase (PGA) activity was screened from a metagenomic library by using a medium containing penicillin G. A novel PGA gene from the inserted fragment of ACPGA001 was obtained by sequencing. The amino acid sequence of ACPGA001 PGA exhibited <33 % similarity to PGAs retrieved from GenBank. This gene was expressed in Escherichia coli M15 and the recombinant protein was purified and characterized. The ACPGA001 PGA exhibited a maximum activity at 60 °C and showed high activity at pH 4-10 with an optimum pH of 8.0. This enzyme was stable at 40 °C for 70 min with a half-life of 60 min at 55 °C. These beneficial characteristics of ACPGA001 PGA provide some advantages for the potential application of ACPGA001 PGA in industry.

Diversity and potential host-interactions of viruses inhabiting deep-sea seamount sediments.

Seamounts are globally distributed across the oceans and form one of the major oceanic biomes. Here, we utilized combined analyses of bulk metagenome and virome to study viral communities in seamount sediments in the western Pacific Ocean. Phylogenetic analyses and the protein-sharing network demonstrate extensive diversity and previously unknown viral clades. Inference of virus-host linkages uncovers extensive interactions between viruses and dominant prokaryote lineages, and suggests that viruses play significant roles in carbon, sulfur, and nitrogen cycling by compensating or augmenting host metabolisms. Moreover, temperate viruses are predicted to be prevalent in seamount sediments, which tend to carry auxiliary metabolic genes for host survivability. Intriguingly, the geographical features of seamounts likely compromise the connectivity of viral communities and thus contribute to the high divergence of viral genetic spaces and populations across seamounts. Altogether, these findings provides knowledge essential for understanding the biogeography and ecological roles of viruses in globally widespread seamounts.

Preparation and Embedding Characterization of Hydroxypropyl-ß-cyclodextrin/Menthyl Acetate Microcapsules with Enhanced Stability.

OBJECTIVE: Hydroxypropyl-ß-cyclodextrin (HP-ß-CD)/menthyl acetate (MA) microcapsules were developed to overcome the volatile and unstable defects of MA and improve the ease of use and storage. METHODS: MA microcapsules were prepared via spray drying using HP-ß-CD as the wall material. The embedding rate of MA microcapsules was determined through gas chromatography. The embedding characteristics were studied using phase solubility and nuclear magnetic resonance (NMR). The stability was characterized via differential scanning calorimetry (DSC) and the release and retention rates of MA microcapsules at different temperatures. RESULTS: The embedding rate of HP-ß-CD /MA microcapsules was 96.3%. The Gibbs free energy change, enthalpy change and entropy change of the embedding reaction between HP-ß-CD and MA were all less than zero, indicating that the embedding process was a spontaneous exothermic reaction. NMR spectra showed that MA entered the cavity of HP-ß-CD through the large opening end and interacted with the inner wall of the small opening end. DSC and the release and retention rates of MA microcapsules at different temperatures showed that the stability of MA was significantly enhanced after being embedded in HP-ß-CD. CONCLUSION: The HP-ß-CD/MA microcapsules are able to significantly improve the stability of MA and reduce the volatilization of MA.

Characterization and Comparative Genomic Analysis of a Deep-Sea Bacillus Phage Reveal a Novel Genus.

As the most abundant biological entities, viruses are the major players in marine ecosystems. However, our knowledge on virus diversity and virus-host interactions in the deep sea remains very limited. In this study, vB_BteM-A9Y, a novel bacteriophage infecting Bacillus tequilensis, was isolated from deep-sea sediments in the South China Sea. vB_BteM-A9Y has a hexametric head and a long, complex contractile tail, which are typical features of myophages. vB_BteM-A9Y initiated host lysis at 60 min post infection with a burst size of 75 PFU/cell. The phage genome comprises 38,634 base pairs and encodes 54 predicted open reading frames (ORFs), of which 27 ORFs can be functionally annotated by homology analysis. Interestingly, abundant ORFs involved in DNA damage repair were identified in the phage genome, suggesting that vB_BteM-A9Y encodes multiple pathways for DNA damage repair, which may help to maintain the stability of the host/phage genome. A BLASTn search of the whole genome sequence of vB_BteM-A9Y against the GenBank revealed no existing homolog. Consistently, a phylogenomic tree and proteome-based phylogenetic tree analysis showed that vB_BteM-A9Y formed a unique branch. Further comparative analysis of genomic nucleotide similarity and ORF homology of vB_BteM-A9Y with its mostly related phages showed that the intergenomic similarity between vB_BteM-A9Y and these phages was 0-33.2%. Collectively, based on the comprehensive morphological, phylogenetic, and comparative genomic analysis, we propose that vB_BteM-A9Y belongs to a novel genus under Caudoviricetes. Therefore, our study will increase our knowledge on deep-sea virus diversity and virus-host interactions, as well as expanding our knowledge on phage taxonomy.