Abyssibius alkaniclasticus gen. nov., sp. nov., a novel member of the family Rhodobacteraceae, isolated from the Mariana Trench

A Gram-stain-negative bacterium with rod-shaped or irregular cells approximately 0.5-0.9×2.0-3.8 µm in size, designated as 960558^T, was isolated from sediment sampled in the Mariana Trench. Strain 960558^T grows at 4-37 °C (optimum, 28 °C), pH 6-7 (optimum, pH 7) and in the presence of 1-5 % (w/v) NaCl (optimum, 3 %). Strain 960558^T utilizes tetradecane or hexadecane as a sole carbon and energy source, respectively. Phylogenetic trees based on 16S rRNA gene sequences and phylogenomic reconstruction revealed a close phylogenetic relationship between strain 960558^T and members of the family Rhodobacteraceae by forming a separate branch within the type species of closely related genera. The validly published species that is most closely related to strain 960558^T is Planktotalea lamellibrachiae JAM 119^T, which has the highest 16S rRNA gene sequence similarity (93.47 %). Ubiquinone 10 is the predominant ubiquinone, while C_16 : 0, 11-methyl C_18 : 1  ω7c and C_18 : 1  ω7c and/or C_18 : 1  ω6c are the predominant fatty acids (>10 %). Additionally, phosphatidylglycerol, glycolipids, diphosphatidylglycerol, unidentified polar lipids and unidentified aminolipids are the major polar lipids. The DNA G+C content of strain 960558^T is 61 %. Average nucleotide identity and digital DNA-DNA hybridization results of strain 960558^T with other type strains are <70.2 and 22.1 %, respectively. Based on its phylogenetic, chemotaxonomic and other phenotypic properties, strain 960558^T is considered to represent a novel genus and species within the family Rhodobacteraceae, for which the name Abyssibius alkaniclasticus gen. nov., sp. nov. is proposed. The type strain of Abyssibius alkaniclasticus is 960558^T (=KCTC 82619^T=MCCC 1K04727^T).

The Rare Actinobacterium Crossiella sp. Is a Potential Source of New Bioactive Compounds with Activity against Bacteria and Fungi

Antimicrobial resistance has become a global problem in recent decades. A gradual reduction in drug discoveries has led to the current antimicrobial resistance crisis. Caves and other subsurface environments are underexplored thus far, and they represent indispensable ecological niches that could offer new molecules of interest to medicine and biotechnology. We explored Spanish show caves to test the bioactivity of the bacteria dwelling in the walls and ceilings, as well as airborne bacteria. We reported the isolation of two strains of the genus Crossiella, likely representing a new species, isolated from Altamira Cave, Spain. In vitro and in silico analyses showed the inhibition of pathogenic Gram-positive and Gram-negative bacteria, and fungi, as well as the taxonomical distance of both strains from their closest relative, Crossiella cryophila. The presence of an exclusive combination of gene clusters involved in the synthesis of lanthipeptides, lasso peptides, nonribosomal peptides and polyketides indicates that species of this genus could represent a source of new compounds. Overall, there is promising evidence for antimicrobial discovery in subterranean environments, which increases the possibility of identifying new bioactive molecules.

Airborne bacteria in show caves from Southern Spain

This work presents a study on the airborne bacteria recorded in three Andalusian show caves, subjected to different managements. The main differences within the caves were the absence of lighting and phototrophic biofilms in Cueva de Ardales, the periodic maintenance and low occurrence of phototrophic biofilms in Gruta de las Maravillas, and the abundance of phototrophic biofilms in speleothems and walls in Cueva del Tesoro. These factors conditioned the diversity of bacteria in the caves and therefore there are large differences among the CFU m-3, determined using a suction impact collector, equipment widely used in aerobiological studies. The study of the bacterial diversity, inside and outside the caves, indicates that the air is mostly populated by bacteria thriving in the subterranean environment. In addition, the diversity seems to be related with the presence of abundant phototrophic biofilms, but not with the number of visitors received by each cave.

Paracoccus onubensis sp. nov., a novel alphaproteobacterium isolated from the wall of a show cave

A novel facultatively anaerobic, non-motile, Gram-stain-negative, non-endospore-forming alphaproteobacterium, strain 1011MAR3C25^T, was isolated from a white biofilm colonizing the walls of the Andalusian show cave Gruta de las Maravillas (Huelva, Spain). Strain 1011MAR3C25^T grew at 8–42 °C (optimum, 20–30 °C), at pH 5.0–9.0 (optimum, pH 5.0–6.0) and in the presence of 0–12 % (w/v) NaCl (optimum 3–5 %). Cells were catalase- and oxidase-positive. The strain grew heterotrophically with various carbon sources and chemoautotrophically with thiosulfate under aerobic conditions. Results of phylogenetic analysis showed that strain 1011MAR3C25^T was related to Paracoccus saliphilus DSM 18447^T and Paracoccus alkanivorans LMG 30882^T (97.90 % and 97.32 % 16S rRNA sequence identity values, respectively). The major respiratory quinone was ubiquinone Q-10 and the predominant fatty acid was C_18 : 1ω7c. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol, an unidentified aminolipid, an unidentified glycolipid and an unidentified polar lipid. The DNA G+C content was 60.3 mol%. Based on a polyphasic taxonomic study it is proposed that strain 1011MAR3C25^T (=CECT 9092^T=LMG 29414^T) represents a novel species of the genus Paracoccus, for which the name Paracoccus onubensis sp. nov. is proposed.

Diversity and Seasonal Dynamics of Airborne Fungi in Nerja Cave, Spain

Nerja Cave, Southern Spain, was revealed as an important biodiversity reservoir from which several novel species of Aspergillus were described. We carried out an aerobiological study in Nerja Cave to assess the origin of airborne fungi. This study quantified the fungi present in the air of ten representative halls covering the three sectors comprising the cave: Touristic Galleries, High Galleries, and New Galleries. Microclimatological monitoring allowed us to understand the dynamic of airborne fungi in two seasons of the year (winter and summer), corresponding to the strongest and the lowest cave ventilation, and to validate the influence that the transport of airborne fungi from outside may have on the cave itself. The data show that cold air enters in winter, as confirmed by the abundant presence of Aspergillus and Penicillium spores inside and outside the cave. In summer, the abundance of some fungi in the air of Nerja Cave, which are not detected outside, indicates a stagnation or low ventilation, and therefore, the concentration of fungal spores is maxima. The high occurrence of Cladosporium outside the cave and the scarce abundance inside support the cave stagnation in this season.

Paracoccus indicus sp. nov., isolated from surface seawater in the Indian Ocean

Strain IO390502^T, isolated from surface seawater in the Indian Ocean, was characterised using a polyphasic taxonomy approach. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain IO390502^T belongs to the genus Paracoccus and is closely related to Paracoccus seriniphilus DSM 14827^T (97.6%), followed by P. zeaxanthinifaciens JCM 21774^T (97.5%), P. homiensis DSM 17862^T (97.3%), P. marcusii DSM 11574^T (97.2%), P. haeundaensis BC 74171^T (97.0%) and P. carotinifaciens E-396^T (97.0%). Cells are Gram-negative, aerobic, poly-β-hydroxybutyrate-accumulating, motile, rod-shaped, and forms creamy-white colonies. Optimal growth occurred at 25-30 °C, pH 5-8, and in the presence of 3-8% NaCl. The genome of strain IO390502^T has a G+C content of 64.9 mol% and a 3.5 Mb chromosome. The in silico DNA-DNA hybridisation and average nucleotide identity values between strain IO390502^T and the three closely related taxa, P. seriniphilus DSM 14827^T, P. zeaxanthinifaciens JCM 21774^T and P. homiensis DSM 17862^T, are 19.6%, 21.9% and 20.6%, and 76.0%, 79.9% and 77.8%, respectively. Phosphatidylglycerol is the major lipid present, ubiquinone-10 (Q-10) is the sole isoprenoid quinone, and the major cellular fatty acid is C_18:1ω7c. Based on data from phenotypic tests and genotypic differences between strain IO390502^T and its close phylogenetic relatives, strain IO390502^T represents a new species belonging to the genus Paracoccus, for which the name Paracoccus indicus sp. nov. is proposed. The type strain is IO390502^T (= JCM 32637^T = CCTCC AB 2018071^T).

Paracoccus pueri sp. nov., isolated from Pu'er tea

A Gram-stain negative, aerobic, short rod-shaped, motile by flagella bacterial strain (THG-N2.35^T), was isolated from Pu'er tea. Growth occurred at 10-40 °C (optimum 28 °C), at pH 4-7 (optimum 7) and at 0-5% NaCl (optimum 1%). Based on 16S rRNA gene sequence analysis, the near phylogenetic neighbours of strain THG-N2.35^T were identified as Paracoccus hibisci KACC 18632^T (99.0%), Paracoccus tibetensis CGMCC 1.8925^T (98.7%), Paracoccus beibuensis CGMCC 1.7295^T (98.2%), Paracoccus aestuarii KCTC 22049^T (98.2%), Paracoccus rhizosphaerae LMG 26205^T (98.1%), Paracoccus zeaxanthinifaciens ATCC 21588^T (97.1%), Paracoccus marcusii DSM 11574^T (97.0%). Levels of similarity between strain THG-N2.35^T and other Paracoccus species were lower than 97.0%. DNA-DNA hybridization values between strain THG-N2.35^T and P. hibisci KACC 18632^T, P. tibetensis CGMCC 1.8925^T, P. beibuensis CGMCC 1.7295^T, P. aestuarii KCTC 22049^T, P. rhizosphaerae LMG 26205^T, P. zeaxanthinifaciens ATCC 21588^T, P.marcusii DSM 11574^T were 47.5% (42.3%, reciprocal analysis), 36.1% (32.3%), 24.7% (22.1%), 19.2% (16.3%), 11.3% (8.8%), 11.1% (10.8%), 6.1% (5.8%), respectively. The DNA G+C content of strain THG-N2.35^T was 62.3 mol%. The polar lipids were diphosphatidylglycerol, phosphatidyl-N-methylethanolamine, phosphatidylethanolamine, phosphatidylglycerol and phosphatidylcholine. The quinone was ubiquinone-10 (Q-10). The major fatty acids were C_10:0 3OH, C_16:0, C_18:0 and C_18:1 ω7ϲ. On the basis of the phylogenetic analysis, chemotaxonomic data, physiological characteristics and DNA-DNA hybridization data, strain THG-N2.35^T represent a novel species of the genus Paracoccus, for which the name Paracoccus pueri sp. nov. is proposed. The type strain is THG-N2.35^T (= KACC 18934^T = CCTCC AB 2016177^T).

Paracoccus alimentarius sp. nov., isolated from a Korean foodstuff, salted pollack

A Gram-stain-negative, aerobic, non-motile and coccoid or ovoid bacterial strain, designated LB2^T, was isolated from a Korean foodstuff, salted pollack. Strain LB2^T grew optimally at 25-30 °C, at pH 7.0-8.0 and in the presence of 0-2.0 % (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences showed that strain LB2^T belonged to the genus Paracoccus, coherently clustering with the type strain of Paracoccus sulfuroxidans. Strain LB2^T exhibited 16S rRNA gene sequence similarity values of 98.0 and 97.0 % to the type strains of P. sulfuroxidans and Paracoccus halophilus, respectively, and of less than 96.9 % to the type strains of other Paracoccus species. Strain LB2^T contained Q-10 as the predominant ubiquinone. Major fatty acids of strain LB2^T were cyclo C19 : 0ω8c, C18 : 1ω7c and C16 : 0 (when grown on MA) or C18 : 1ω7c and C16 : 0 (on TSA). The major polar lipids detected in strain LB2^T were phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, one unidentified aminolipid and one unidentified glycolipid. The DNA G+C content of strain LB2^T was 61.4 mol% and its DNA-DNA relatedness values with the type strains of P. sulfuroxidans and P. halophilus were 26 and 18 %, respectively. Differential phenotypic properties, together with its phylogenetic and genetic distinctiveness, revealed that strain LB2^T is separated from recognized Paracoccus species. On the basis of the data presented, strain LB2^T is considered to represent a novel species of the genus Paracoccus, for which the name Paracoccus alimentarius sp. nov. is proposed. The type strain is LB2^T (=KCTC 62138^T=NBRC 113023^T).

Paracoccus sordidisoli sp. nov., isolated from an agricultural field contaminated with hexachlorocyclohexane isomers

A novel bacterial strain, designated LP91^T, was isolated from an agricultural field contaminated with hexachlorocyclohexane (HCH) isomers at Ummari Village, Lucknow, Uttar Pradesh, India. Cells of the strain were aerobic, short rod or coccoid, Gram-stain-negative and non-motile. Colonies of the strain were initially transparent but with time changed to a creamy white colour. Phylogenetic analysis based on the 16S rRNA marker gene showed that it was closely associated with Paracoccus aestuariivivens GHD-30^T (99.1 %) and Paracoccus limosus NB88^T (98.0 %), followed by Paracoccus laeviglucosivorans 43P^T (97.9 %) and Paracoccus marinus KKL-A5^T (97.0 %). The DNA-DNA hybridization values of strain LP91^T with the closely related type strains mentioned above were below 51.2±0.64 %, confirming it as a distinct species from other known species of the genus Paracoccus. The major cellular fatty acids of strain LP91^T were C18 : 0 ω7c/C18 : 0 ω6c and C16 : 0. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine and aminophospholipid, along with other lipids including glycolipids, aminolipids and other unknown phosphoglycolipids. Spermine was the major polyamine, along with putrescine in a minor amount. Ubiquinone (Q-10) was the sole isoprenoid quinone. Based on the results of phylogenetic, phenotypic and chemotaxonomic analysis, it is proposed that the isolate represents a new species of the genus Paracoccus, for which the name Paracoccus sordidisoli sp. nov. is proposed. The type strain is LP91^T (=KCTC 42938^T=CCM 8696^T=MCC 3128^T).

Paracoccus hibisci sp. nov., isolated from the rhizosphere of Hibiscus syriacus L. (Mugunghwa flower)

A Gram-stain-negative, aerobic, short-rod-shaped bacterium, motile by means of one flagellum (THG-T2.8T), was isolated from the rhizosphere of Mugunghwa flower. Growth occurred at 10-37 °C (optimum 28 °C), at pH 6-8 (optimum 7) and with 0-5 % NaCl (optimum 1 %). The major quinone was ubiquinone-10 (Q-10). The major fatty acids were C10 : 0 3-OH, C16 : 0, C18 : 0 and C18 : 1ω7c. The polar lipids were diphosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylethanolamine, phosphatidylglycerol, one unidentified aminolipid, two unknown phospholipids, one unknown glycolipid and one unidentified lipid. The DNA G+C content of strain THG-T2.8T was 65.5 mol%. Based on 16S rRNA gene sequence analysis, the nearest phylogenetic neighbours of strain THG-T2.8T were identified as Paracoccus tibetensis Tibet-S9a3T (98.6 %), Paracoccus aestuarii B7T (98.4 %), Paracoccus rhizosphaerae CC-CCM15-8T (98.3 %) and Paracoccus beibuensis JLT1284T (98.2 %). Levels of sequence similarity among strain THG-T2.8T and other species of the genus Paracoccus were lower than 98.0 %. DNA-DNA hybridization values between strain THG-T2.8T and P. tibetensis Tibet-S9A3TT, P. aestuarii B7T, P. rhizosphaerae CC-CCM15-8T and P. beibuensisJLT1284T were 36.5 % (38.8 %, reciprocal analysis), 32.8 % (34.8 %), 31.6 % (33.8 %) and 15.3 % (24.8 %), respectively. On the basis of the phylogenetic analysis, chemotaxonomic data, physiological characteristics and DNA-DNA hybridization data, strain THG-T2.8T represents a novel species of the genus Paracoccus, for which the name Paracoccus hibisci sp. nov. is proposed. The type strain is THG-T2.8T (=KACC 18932T=CCTCC AB 2016181T).