Characterization of two novel psychrophilic and piezotolerant strains, Shewanella psychropiezotolerans sp. nov. and Shewanella eurypsychrophilus sp. nov, adapted to an extreme deep-sea environment.

Three marine bacterial strains designated YLB-06T, YLB-08T and YLB-09 were isolated under high hydrostatic pressure from deep-sea sediment samples collected from the Southwest Indian Ocean. They were Gram-stain-negative, oxidase- and catalase-positive, facultative anaerobic and motile. In addition, the strains were capable of growing at 0-20 °C (optimum 4-10 °C) and 0.1-40 MPa (optimum 0.1 MPa), were psychrophiles and piezotolerant, and could use trimethylamine N-oxide (TMAO), DMSO, elemental sulfur and insoluble Fe (III) as terminal electron acceptors during anaerobic growth. Strain YLB-06T could also use nitrate, and strains YLB-08T and YLB-09 could use nitrite as a terminal electron acceptor. Phylogenetic tree analyses based on 16S rRNA gene sequences and 400 optimized universal marker sequences indicated that the strains belonged to the genus Shewanella. The 16S rRNA gene highest similarity, together with the estimated ANI and DDH values for these strains with their related type strains, were below the respective thresholds for species differentiation. The ANI and DDH values between YLB-08T and YLB-09 were 99.9% and 91.8%, respectively, implying that they should belong to the same genospecies. The YLB-06T genome had duplicated genes, and multiple movement modalities, attachment modalities, biofilm synthesis systems, intercellular interactions and a strong antioxidant system, which were all beneficial for survival in an extreme deep-sea environment. The G + C contents of strains YLB-06T, YLB-08T and YLB-09 were 45.1, 43.5 and 43.6 mol%, respectively. Based on polyphasic taxonomic properties, two novel psychropiezotolerant species are proposed, Shewanella psychropiezotolerans sp. nov. with YLB-06T (=MCCC 1A12715T = KCTC 62907T) and S. eurypsychrophilus sp. nov with YLB-08T (=MCCC 1A12718T = KCTC 62909T) as type strains.

Pseudoroseicyclus tamaricis sp. nov., isolated from seashore sediment of a Tamarix chinensis forest and emended descriptions of the genus Pseudoroseicyclus Park et al. 2016.

An aerobic, Gram-stain-negative, bacterium, designated CLL3-39T was isolated from seashore sediment collected at a Tamarix chinensis forest in the Marine Ecology Special Reserve of Changyi, Shandong Province, PR China. Cells of strain CLL3-39T were olive-shaped and no flagellum was observed. Strain CLL3-39T grew optimally at 33 °C, pH 7.5 and salinity (sea salts) of 40 g l-1. The main fatty acids in the cell membrane of strain CLL3-39T comprised anteiso-C15 : 0 (22.3 %), iso-C15 : 0 (14.0 %), C16 : 0 (9.2 %) and summed feature 8 (contains C18 : 1 ω7c/C18 : 1 ω6c. 26. 7 %). The main polar lipids of CLL3-39T were phosphatidylglycerol, diphosphatidylglycerol and phosphatidylcholine. The respiratory quinone was Q10. The G+C content of the genomic DNA of strain CLL3-39T was 69.6 mol%. The average nucleotide identity between CLL3-39T and Pseudoroseicyclus aestuarii DB-4T was 74.7 % and the in silico DNA-DNA hybridization value was 20.1 %. Phylogenetically, strain CLL3-39T belonged to the genus Pseudoroseicyclus, branching with only one type strain P. aestuarii DB-4T with 96.3 % 16S rRNA gene similarity, followed by Limimaricola cinnabarinus LL-001T (95.2 %). Based on its phenotypic, phylogenetic and chemotaxonomic characteristics, we propose strain CLL3-39T (=MCCC 1A14815T =KCTC 72665T) as a representative of a novel species in the genus Pseudoroseicyclus, for which the name Pseudoroseicyclus tamaricis sp. nov. is proposed.

Discovery of andrastones from the deep-sea-derived Penicillium allii-sativi MCCC 3A00580 by OSMAC strategy.

Andrastones are unusual 6,6,6,5-tetracyclic meroterpenoids that are rarely found in nature. Previously, three andrastones were obtained from the rice static fermentation extract of the deep-sea-derived fungus Penicillium allii-sativi MCCC 3A00580. Inspired by one strain many compounds (OSMAC) approach, the oat static fermentation on P. allii-sativi was conducted. As a result, 14 andrastones were isolated by UV-guided isolation. The chemical structures of the nine new compounds (1-9) was established by comprehensive analysis of the NMR, MS, ECD, and X-ray crystallography and the five known ones (10-14) were assigned by comparing their NMR, MS, and OR data with those reported in literature. Compound 1 bears a novel hemiketal moiety while 2 is the first example to possess a novel tetrahydrofuran moiety via C-7 and C-15. All isolates were tested for anti-allergic bioactivity. Compound 10, 3-deacetylcitreohybridonol, significantly decreased degranulation with the IC50 value of 14.8 µM, compared to that of 92.5 µM for the positive control, loratadine. Mechanism study indicated 10 could decrease the generation of histamine and TNF-α by reducing the accumulation of Ca2+ in RBL-2H3 cells. These findings indicate andrastones could be potential to discover new anti-allergic candidate drugs.

Marinobacter changyiensis, sp. nov., isolated from offshore sediment.

An aerobic, Gram-stain-negative bacterium, designated CLL7-20T, was isolated from a marine sediment sample from offshore of Changyi, Shandong Province, China. Cells of strain CLL7-20T were rod-shaped, motile with one or more polar flagella, and grew optimally at pH 7.0, at 28 °C and with 3 % (w/v) NaCl. The principal fatty acids of strain CLL7-20T were C16 : 0 and summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c). The main polar lipids of strain CLL7-20T were phosphatidylethanolamine (PE), phosphatidylglycerol (PG), diphosphatidylglycerol (DPG) and an unidentified aminolipid (AL). Strain CLL7-20T contained Q-9 as the major respiratory quinone. The G+C content of its genomic DNA was 56.2 mol%. Phylogenetically, strain CLL7-20T branched within the genus Marinobacter, with M. daqiaonensis YCSA40T being its closest phylogenetic relative (96.7 % 16S rRNA gene sequence similarity), followed by M. sediminum R65T (96.6 %). Average nucleotide identity and in silico DNA-DNA hybridization values between strain CLL7-20T and the closest related reference strains were 73.2% and 19.8 %, respectively. On the basis of its phenotypic, phylogenetic and chemotaxonomic characteristics, we suggest that strain CLL7-20T (=MCCC 1A14855T=KCTC 72664T) is the type strain of a novel species in the genus Marinobacter, for which the name Marinobacter changyiensis sp. nov. is proposed. Based on the genomic analysis, siderophore genes were found from strain CLL7-20T, which indicate its potential as a promising alternative to chemical fertilizers in iron-limitated environments such as saline soils.

Shewanella intestini sp. nov., isolated from the intestine of abalone, Haliotis diversicolor.

A Gram-stain-negative, rod-shaped bacterium with a singular polar flagellum, designated as strain XMDDZSB0408T, was isolated from the intestine of adult abalone, Haliotis diversicolor. Activity of oxidase was positive and catalase activity was negative. It could grow at salinities from 3 to 6 % NaCl (w/v), and pH 7-9. It had the highest sequence similarity of <96.0 % with all previously established species for the complete 16S rRNA gene (1531 bp). The results of phylogenetic analysis indicated that the strain was affiliated to the genus Shewanella and closely related to Shewanella gaetbuli TF-27T and Shewanella japonica KMM 3299T (95.8 % sequence similarity), Shewanella electrodiphila MAR441T (95.6 %), Shewanella pacifica KMM 3597T (95.4 %), Shewanella donghaensis LT17T (95.3 %) and Shewanella olleyana ACEM 9T (94.7 %). The respiratory quinones were MK-7, Q-8, Q-7, MK-8, Q-7 (H4) and Q-6. The predominant fatty acids consisted of C16:0, summed feature 3 (comprised of C16 : 1ω7c/C16 : 1ω6c), C18 : 0, summed feature 8 (comprised of C18 : 1ω7c/C18 : 1ω6c), C12 : 0 and C14 : 0. The polar lipids were identified as phosphatidylethanolamine (PE), a glycolipid (GL), a phospholipid (PL) and one unidentified lipid (L). The DNA G+C content was 41.4 mol% calculated from the draft genome sequence. On the basis of its polyphasic taxonomic properties, strain XMDDZSB0408T represented a novel species, for which the name Shewanella intestini sp. nov. was proposed, with the type strain XMDDZSB0408T (=KCTC 52125T=MCCC 1A01895T).