Bacterial symbionts of the precious coral Corallium rubrum are differentially distributed across colony-specific compartments and differ among colormorphs.

Corals engage in symbioses with micro-organisms that provide nutrients and protect the host. Where the prokaryotic microbes perform their symbiotic functions within a coral is, however, poorly understood. Here, we studied the tissue-specific microbiota of the coral Corallium rubrum by dissecting its tissues from the skeleton and separating the white polyps from the red-coloured coenenchyme, followed by 16S rRNA gene metabarcoding of the three fractions. Dissection was facilitated by incubating coral fragments in RNAlater, which caused tissues to detach from the skeleton. Our results show compartmentalisation of the microbiota. Specifically, Endozoicomonas, Parcubacteria and a Gammaproteobacteria were primarily located in polyps, whereas Nitrincolaceae and one Spirochaeta phylotype were found mainly in the coenenchyme. The skeleton-associated microbiota was distinct from the microbiota in the tissues. Given the difference in tissue colour and microbiota of the polyps and coenenchyme, we analysed the microbiota of three colormorphs of C. rubrum (red, pink, white), finding that the main difference was a very low abundance of Spirochaeta in white colormorphs. While the functions of C. rubrum's symbionts are unknown, their localisation within the colony suggests that microhabitats exist, and the presence of Spirochaeta appears to be linked to the colour of C. rubrum.

Arsenophonus symbiosis with louse flies: multiple origins, coevolutionary dynamics, and metabolic significance.

IMPORTANCE: Insects that live exclusively on vertebrate blood utilize symbiotic bacteria as a source of essential compounds, e.g., B vitamins. In louse flies, the most frequent symbiont originated in genus Arsenophonus, known from a wide range of insects. Here, we analyze genomic traits, phylogenetic origins, and metabolic capacities of 11 Arsenophonus strains associated with louse flies. We show that in louse flies, Arsenophonus established symbiosis in at least four independent events, reaching different stages of symbiogenesis. This allowed for comparative genomic analysis, including convergence of metabolic capacities. The significance of the results is twofold. First, based on a comparison of independently originated Arsenophonus symbioses, it determines the importance of individual B vitamins for the insect host. This expands our theoretical insight into insect-bacteria symbiosis. The second outcome is of methodological significance. We show that the comparative approach reveals artifacts that would be difficult to identify based on a single-genome analysis.

Spartinivicinus marinus sp. nov., isolated from intertidal sediment.

A Gram-stain-negative, aerobic, flagellated, and long rod-shaped bacterium, designated strain SM1973T, was isolated from an intertidal sediment sample collected from the coast of Qingdao, PR China. Strain SM1973T grew at 15-37 °C and with 0-5.5 % NaCl. It reduced nitrate to nitrite and hydrolysed aesculin but did not hydrolyse casein and gelatin. The strain showed the highest 16S rRNA gene sequence similarity (98.2 %) to the type strain of Spartinivicinus ruber. The phylogenetic trees based on the 16S rRNA genes and single-copy orthologous clusters showed that strain SM1973T clustered with S. ruber, forming a separate lineage within the family Zooshikellaceae. The major cellular fatty acids were summed feature 3 (C16 : 1 ω7с and/or C16 : 1 ω6с) and C16 : 0. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The main respiratory quinone was ubiquinone-9. The genomic DNA G+C content of strain SM1973T was 40.4 mol%. Based on the polyphasic evidence presented in this paper, strain SM1973T is considered to represent a novel species within the genus Spartinivicinus, for which the name Spartinivicinus marinus sp. nov. is proposed. The type strain is SM1973T (=MCCC 1K04833T=KCTC 72846T).

Bacterial Community Shifts during Polyp Bail-Out Induction in Pocillopora Corals.

Polyp bail-out constitutes both a stress response and an asexual reproductive strategy that potentially facilitates dispersal of some scleractinian corals, including several dominant reef-building taxa in the family Pocilloporidae. Recent studies have proposed that microorganisms may be involved in onset and progression of polyp bail-out. However, changes in the coral microbiome during polyp bail-out have not been investigated. In this study, we induced polyp bail-out in Pocillopora corals using hypersaline and hyperthermal methods. Bacterial community dynamics during bail-out induction were examined using the V5-V6 region of the 16S-rRNA gene. From 70 16S-rRNA gene libraries constructed from coral tissues, 1,980 OTUs were identified. Gammaproteobacteria and Alphaproteobacteria consistently constituted the dominant bacterial taxa in all coral tissue samples. Onset of polyp bail-out was characterized by increased relative abundance of Alphaproteobacteria and decreased abundance of Gammaproteobacteria in both induction experiments, with the shift being more prominent in response to elevated temperature than to elevated salinity. Four OTUs, affiliated with Thalassospira, Marisediminitalea, Rhodobacteraceae, and Myxococcales, showed concurrent abundance increases at the onset of polyp bail-out in both experiments, suggesting potential microbial causes of this coral stress response. IMPORTANCE Polyp bail-out represents both a stress response and an asexual reproductive strategy with significant implications for reshaping tropical coral reefs in response to global climate change. Although earlier studies have suggested that coral-associated microbiomes likely contribute to initiation of polyp bail-out in scleractinian corals, there have been no studies of coral microbiome shifts during polyp bail-out. In this study, we present the first investigation of changes in bacterial symbionts during two experiments in which polyp bail-out was induced by different environmental stressors. These results provide a background of coral microbiome dynamics during polyp bail-out development. Increases in abundance of Thalassospira, Marisediminitalea, Rhodobacteraceae, and Myxococcales that occurred in both experiments suggest that these bacteria are potential microbial causes of polyp bail-out, shedding light on the proximal triggering mechanism of this coral stress response.

Agriterribacter soli sp. nov., isolated from herbicide-contaminated soil.

A Gram-stain-negative, non-spore-forming and rod-shaped bacterium, designated strain NS-102T, was isolated from herbicide-contaminated soil sampled in Nanjing, PR China, and its taxonomic status was investigated by a polyphasic approach. Cell growth of strain NS-102T occurred at 16-42 °C (optimum, 30 °C), at pH 5.0-8.0 (optimum, pH 6.0) and in the presence of 0-3.5 % (w/v) NaCl (optimum, without addition of NaCl). The 16S rRNA gene sequence of strain NS-102T shows high similarity to that of Agriterribacter humi YJ03T (96.9 % similarity), followed by Terrimonas terrae T16R-129T (93.8 %) and Terrimonas pekingensis QHT (93.6 %). Average nucleotide identity, average amino acid identity and digital DNA-DNA hybridization values between the draft genomes of strain NS-102T and A. humi YJ03T were 72.5, 69.4 and 18.6%, respectively. The only respiratory quinone was MK-7, and phosphatidylethanolamine and unidentified lipids were the major polar lipids. The major cellular fatty acids of strain NS-102T contained high amounts of iso-C15 : 0 (24.6 %), iso-C17 : 03-OH (24.1 %), iso-C15 : 0 G (16.6 %) and summed feature 3 (C16 : 1 ω6c and/or C16 : 1 ω7c) (15.6 %). The G+C content of the total DNA was determined to be 40.0 mol%. The morphological, physiological, chemotaxonomic and phylogenetic analyses clearly distinguished this strain from its closest phylogenetic neighbours. Thus, strain NS-102T represents a novel species of the genus Agriterribacter, for which the name Agriterribacter soli sp. nov. is proposed. The type strain is NS-102T (=CCTCC AB 2017249T=KCTC 62322T).

Phylogenomics of the Phylum Proteobacteria: Resolving the Complex Relationships.

Proteobacteria is one of the largest and phenotypically most diverse divisions within the domain bacteria. Due to the economic importance, this phylum demands an urgent need for a clear and scientifically sound classification system to streamline their characterization. The goal of our study was to carefully reevaluate the current system of classification and suggest changes wherein necessary. Phylogenetic trees of 84 Proteobacteria were constructed using single gene-based phylogeny involving 16S rRNA genes and protein sequences of 85 conserved genes, whole genome-based phylogenetic tree using CVtree3.0, amino acid Identity matrix tree, and concatenated tree with aforementioned conserved genes. The results of our study confirm the polyphyletic relationship between Desulfurella acetivorans, a Deltaproteobacteria with Epsilonproteobacteria. The group Syntrophobacterales was found to be polyphyletic with respect to Desulfarculus baarsii and the group Thiotrichales was found to be splitting in different phylogenetic trees. Placement of phylogenetic groups belonging to Rhodocyclales, Oceonospirilalles, and Chromatiales is controversial and requires further study and revisions. Based on our analysis, we strongly support reclassification of Magnetococcales as a separate class Etaproteobacteria. From our results, we conclude that concatenated trees of conserved proteins are a more accurate method for phylogenetic analysis, as compared to other methods used.

Novel Insights on Obligate Symbiont Lifestyle and Adaptation to Chemosynthetic Environment as Revealed by the Giant Tubeworm Genome.

The mutualism between the giant tubeworm Riftia pachyptila and its endosymbiont Candidatus Endoriftia persephone has been extensively researched over the past 40 years. However, the lack of the host whole-genome information has impeded the full comprehension of the genotype/phenotype interface in Riftia. Here, we described the high-quality draft genome of Riftia, its complete mitogenome, and tissue-specific transcriptomic data. The Riftia genome presents signs of reductive evolution, with gene family contractions exceeding expansions. Expanded gene families are related to sulfur metabolism, detoxification, antioxidative stress, oxygen transport, immune system, and lysosomal digestion, reflecting evolutionary adaptations to the vent environment and endosymbiosis. Despite the derived body plan, the developmental gene repertoire in the gutless tubeworm is extremely conserved with the presence of a near intact and complete Hox cluster. Gene expression analyses establish that the trophosome is a multifunctional organ marked by intracellular digestion of endosymbionts, storage of excretory products, and hematopoietic functions. Overall, the plume and gonad tissues both in contact to the environment harbor highly expressed genes involved with cell cycle, programed cell death, and immunity indicating a high cell turnover and defense mechanisms against pathogens. We posit that the innate immune system plays a more prominent role into the establishment of the symbiosis during the infection in the larval stage, rather than maintaining the symbiostasis in the trophosome. This genome bridges four decades of physiological research in Riftia, whereas it simultaneously provides new insights into the development, whole organism functions, and evolution in the giant tubeworm.

Emerging Pathogenic Gammaproteobacteria Wohlfahrtiimonas chitiniclastica and Ignatzschineria Species in a Turkey Vulture (Cathartes aura).

New World vultures, such as turkey vultures (Cathartes aura), are obligate scavengers with large geographic ranges. In a preliminary characterization of the turkey vulture (TV) gastrointestinal microbiome in Southern California, we identified 2 recently described emerging bacterial pathogens not previously known to be associated with this avian species. High-throughput sequencing of broad-range 16S rRNA gene amplicons revealed sequences from TV cloacal swabs that were related closest to Wohlfahrtiimonas chitiniclastica and Ignatzschineria species, both Gammaproteobacteria considered by the United States Centers for Disease Control and Prevention as emerging zoonotic pathogens. None of these bacterial sequence types have been previously identified from samples obtained from the turkey vulture gastrointestinal microbiome. With the use of bioinformatics workflows previously established by our research group, we designed specific and sensitive polymerase chain reaction primer sets that represent novel diagnostic assays for the genera Wohlfahrtiimonas and Ignatzschineria. These primer sets were validated by Sanger sequence confirmation from complex TV samples. Because the genera Wohlfahrtiimonas and Ignatzschineria are both known to have dipteran hosts, the molecular diagnostic tools we present here should be useful for better understanding the role of flies, vultures, and other scavengers in the ecology and epidemiology of the genera Wohlfahrtiimonas and Ignatzschineria from a One Health perspective.

Microbes mediating the sulfur cycle in the Atlantic Ocean and their link to chemolithoautotrophy.

Only about 10%-30% of the organic matter produced in the epipelagic layers reaches the dark ocean. Under these limiting conditions, reduced inorganic substrates might be used as an energy source to fuel prokaryotic chemoautotrophic and/or mixotrophic activity. The aprA gene encodes the alpha subunit of the adenosine-5'-phosphosulfate (APS) reductase, present in sulfate-reducing (SRP) and sulfur-oxidizing prokaryotes (SOP). The sulfur-oxidizing pathway can be coupled to inorganic carbon fixation via the Calvin-Benson-Bassham cycle. The abundances of aprA and cbbM, encoding RuBisCO form II (the key CO2 fixing enzyme), were determined over the entire water column along a latitudinal transect in the Atlantic from 64°N to 50°S covering six oceanic provinces. The abundance of aprA and cbbM genes significantly increased with depth reaching the highest abundances in meso- and upper bathypelagic layers. The contribution of cells containing these genes also increased from mesotrophic towards oligotrophic provinces, suggesting that under nutrient limiting conditions alternative energy sources are advantageous. However, the aprA/cbbM ratios indicated that only a fraction of the SOP is associated with inorganic carbon fixation. The aprA harbouring prokaryotic community was dominated by Pelagibacterales in surface and mesopelagic waters, while Candidatus Thioglobus, Chromatiales and the Deltaproteobacterium_SCGC dominated the bathypelagic realm. Noticeably, the contribution of the SRP to the prokaryotic community harbouring aprA gene was low, suggesting a major utilization of inorganic sulfur compounds either as an energy source (occasionally coupled with inorganic carbon fixation) or in biosynthesis pathways.

Single-component near-infrared optogenetic systems for gene transcription regulation.

Near-infrared (NIR) optogenetic systems for transcription regulation are in high demand because NIR light exhibits low phototoxicity, low scattering, and allows combining with probes of visible range. However, available NIR optogenetic systems consist of several protein components of large size and multidomain structure. Here, we engineer single-component NIR systems consisting of evolved photosensory core module of Idiomarina sp. bacterial phytochrome, named iLight, which are smaller and packable in adeno-associated virus. We characterize iLight in vitro and in gene transcription repression in bacterial and gene transcription activation in mammalian cells. Bacterial iLight system shows 115-fold repression of protein production. Comparing to multi-component NIR systems, mammalian iLight system exhibits higher activation of 65-fold in cells and faster 6-fold activation in deep tissues of mice. Neurons transduced with viral-encoded iLight system exhibit 50-fold induction of fluorescent reporter. NIR light-induced neuronal expression of green-light-activatable CheRiff channelrhodopsin causes 20-fold increase of photocurrent and demonstrates efficient spectral multiplexing.

Sulfitobacter algicola sp. nov., isolated from green algae.

A novel Gram-stain-negative, aerobic, non-flagellated, non-motile, oval-rod-shaped and light pink to light tawny-pigmented bacterial strain (designated 1151T) were isolated from marine green algae obtained from the coastal seawater of Weihai, China. Strain 1151T was found to grow at 15-37 °C (optimum, 33 °C), pH 7.0-9.5 (optimum, 7.5-8.5) and in the presence of 1-6% (w/v) NaCl (optimum, 3%). Cells were oxidase-positive and catalase-positive. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain 1151T was a member of the genus Sulfitobacter and exhibited the hightest sequence similarity to Sulfitobacter indolifex DSM 14862T (96.6%), followed by the sequence similarity to Sulfitobacter aestuarii hydD52T (96.5%) and Sulfitobacter profundi SAORIC-263T (96.5%). The average nucleotide identity and digital DDH values between strain 1151T and Sulfitobacter indolifex DSM 14862T were 69.9% and 20.9%, respectively. The average amino acid identity between strain 1151T and Sulfitobacter pontiacus DSM 10014T (type strain of the type species) was 62.3%. Q-10 was detected as the sole respiratory quinone. The dominant cellular fatty acids were sum feature 8 (C18: 1ω7c; 44.1%), C20: 1ω7c (29.7%) and C18: 0 (11.7%). The DNA G + C content of strain 1151T was 51.8 mol%. The polar lipids included phosphatidylglycerol (PG), phosphatidylethanolamine (PE), phosphatidylcholine (PC), and three unidentified lipids (L1, L2 and L3). Based on the phylogenetic and phenotypic characteristics, strain 1151T is considered to represent a novel species of the genus Sulfitobacter, for which the name Sulfitobacter algicola sp. nov. is proposed. The type strain is 1151T (= KCTC 72513T = MCCC 1H00384T).

Chitinophaga agri sp. nov., a bacterium isolated from soil of reclaimed land.

A Gram-negative, aerobic, and long rod-shaped bacterium, designated as H33E-04T, was isolated from the soil of reclaimed land, Republic of Korea. The strain grew at a temperature range of 15-40 °C, pH 5.0-10.0, and 0-2% NaCl (w/v). The phylogenetic analysis based on 16S rRNA gene sequences showed that strain H33E-04T was in the same clade with Chitinophaga pinensis DSM 2588T, Chitinophaga filiformis IFO 15056T, and Chitinophaga ginsengisoli Gsoil 052T with 98.4%, 97.9%, and 97.8% sequence similarities, respectively. The de novo genome assembly revealed that the DNA G + C content of the strain was 46.2 mol%. Comparative genome analysis between strain H33E-04T and C. pinensis DSM 2588 T showed that the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values were 79.9% and 23.4%, respectively. The major respiratory quinone was menaquinone-7 (MK-7) and the predominant cellular fatty acids were iso-C15:0 (31.7%), C16:1 ω5c (31.2%), and iso-C17:0 3-OH (11.8%), supporting the affiliation of strain H33E-04T with the genus Chitinophaga. Based on phylogenetic, physiological, and chemotaxonomic characteristics, strain H33E-04T represents a novel species of the genus Chitinophaga, for which the name Chitinophaga agri sp. nov. is proposed. The type strain of Chitinophaga agri is H33E-04T (= KACC 21303T = NBRC114512T).

Polyphasic taxonomic analysis of Sinimarinibacterium arenosum sp. nov., a halophilic bacterium isolated from marine sediment.

A Gram stain-negative, aerobic, motile, rod-shaped bacterial strain, designated CAU 1509T, was isolated from marine sediment, and its taxonomic position was determined using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CAU 1509T formed a distinct lineage within the genus Sinimarinibacterium with the highest 16S rRNA gene sequence similarity to Sinimarinibacterium flocculans NH6-24T (97.0%). Similar to another member of Sinimarinibacterium, ubiquinone-8 (Q-8) was the predominant quinone, whereas C16:0, summed feature 3 (C16:1ω7c/ω6c) and summed feature 8 (C18:1ω7c/ω6c) were the major cellular fatty acids. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unidentified phospholipid, four unidentified glycolipids and three unidentified aminolipids. Strain CAU 1509T has a genome of 4.54 Mb, including 4251 coding sequences, 6 rRNAs and 50 tRNAs, with a genomic DNA G+C content of 63.2 mol%. Based on its phenotypic, chemotaxonomic and phylogenetic properties, strain CAU 1509T should be classified as a novel species of the genus Sinimarinibacterium, for which the name Sinimarinibacterium arenosum sp. nov. is proposed. The type strain is CAU 1509T (= KCTC 72000T = NBRC 113698T).

Steel slag amendment impacts on soil microbial communities and activities of rice (Oryza sativa L.).

With the increase in iron/steel production, the higher volume of by-products (slag) generated necessitates its efficient recycling. Because the Linz-Donawitz (LD) slag is rich in silicon (Si) and other fertilizer components, we aim to evaluate the impact of the LD slag amendment on soil quality (by measuring soil physicochemical and biological properties), plant nutrient uptake, and strengthens correlations between nutrient uptake and soil bacterial communities. We used 16 S rRNA illumine sequencing to study soil bacterial community and APIZYM assay to study soil enzymes involved in C, N, and P cycling. The LD slag was applied at 2 Mg ha-1 to Japonica and Indica rice cultivated under flooded conditions. The LD slag amendment significantly improved soil pH, plant photosynthesis, soil nutrient availability, and the crop yield, irrespective of cultivars. It significantly increased N, P, and Si uptake of rice straw. The slag amendment enhanced soil microbial biomass, soil enzyme activities and enriched certain bacterial taxa featuring copiotrophic lifestyles and having the potential role for ecosystem services provided to the benefit of the plant. The study evidenced that the short-term LD slag amendment in rice cropping systems is useful to improve soil physicochemical and biological status, and the crop yield.

Some Gammaproteobacteria are enriched within CD14+ macrophages from intestinal lamina propria of Crohn's disease patients versus mucus.

Crohn's disease causes chronic inflammation in the gastrointestinal tract and its pathogenesis remains unclear. In the intestine of Crohn's disease patients, CD14+CD11+CD163low macrophages contribute to inflammation through the induction of Th17 cells and production of inflammatory cytokines; the CD14+CD11c+163high fraction is anti-inflammatory through the production of IL-10 in normal cases. In this report, the 16S rRNA gene amplicon sequencing method was used to identify bacteria that are specifically present in intestinal CD14+CD11c+ macrophages of Crohn's disease patients. Bacteria present in intestinal CD14+CD11c+ macrophages and mucus of Crohn's disease patients were separated into different clusters in principal coordinates analysis. There was a statistically significant increase in the relative composition of CD14+CD11c+ macrophages from mucus in two phyla (Proteobacteria [p = 0.01] and Actinobacteria [p = 0.02]) and two families (Moraxellaceae [p < 0.001] and Pseudomonadaceae [p = 0.01]). In addition, OTU-1: Acinetobacter and OTU-8: Pseudomonadaceae tended to concentrate in the CD14+CD11c+CD163low subset, whereas OTU-10: Proteus, OTU-15: Collinsella tended to concentrate more in the CD14+CD11c+CD163high subset than the other subset and mucus.

Aerosticca soli gen. nov., sp. nov., an aerobic gammaproteobacterium isolated from crude oil-contaminated soil.

An aerobic bacterium, designated strain Dysh456T, was isolated from a crude oil-contaminated soil. Cells of strain Dysh456T were rod-shaped, motile, and Gram-stain-negative. Strain Dysh456T grew at 13-48 °C and pH 4.3-7.9. Major cellular fatty acids were iso-C15:0 (42.5%), iso-C17:0 (15.3%) and summed feature 9 (iso-C17:1 ω9c/C16:0 10-methyl [13.7%]). Major respiratory quinone was ubiquinone-8. The genome of strain Dysh456T consists of a single circular chromosome of 2,874,969 bp in length with G + C content of 68.3%. Phylogenetic analysis based on the 16S rRNA gene sequences indicated that strain Dysh456T belongs to the family Rhodanobacteraceae, but none of the existing genera can accommodate this novel isolate. On the basis of physiological, chemotaxonomic, and genomic properties, strain Dysh456T (= NBRC 112897T = DSM 105662T) is proposed as the type strain representing a novel species of novel genus, for which the name Aerosticca soli gen. nov., sp. nov. is proposed.

Parahaliea maris sp. nov., isolated from surface seawater and emended description of the genus Parahaliea.

A Gram-stain-negative strictly aerobic, short-rod-shaped, and non-motile bacterial strain designated HSLHS9T was isolated from surface seawater collected from the South China Sea. Strain HSLHS9T could grow at 15-41°C (optimum 28°C), at pH 5.0-9.0 (optimum 6.0-7.0), and in 0-7% (w/v) NaCl (optimum 2-3%). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain HSLHS9T shared high identities with the closely related Parahaliea aestuarii S2-26T (98.6%) and Parahaliea mediterranea 7SM29T (97.8%) and formed a distinct lineage within the genus Parahaliea. Wholegenome sequencing of strain HSLHS9T revealed the size of 4.8 Mbp and DNA G + C content of 61.8 mol%. Strain HSLHS9T shared the digital DNA-DNA hybridization values of 22.4% and 23.0%, and the average nucleotide identities of 79.7% and 79.9%, respectively, with the two type strains above. The predominant cellular fatty acids of the strain were summed feature 8 (C18:1ω6c and/or C18:1ω7c), summed feature 3 (C16:1ω7c and/or C16:1ω6c), C17:1ω8c, and C16:0. The sole isoprenoid quinone was identified as Q-8. The polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, aminolipid, and two glycolipids. Based on taxonomic data obtained in this study, it is suggested that strain HSLHS9T represents a novel species of the genus Parahaliea, for which the name Parahaliea maris sp. nov. is proposed. The type strain is HSLHS9T (= MCCC 1A06717T = KCTC 52307T). An emended description of the genus Parahaliea is also provided.

Corallincola spongiicola sp. nov., isolated from sponge.

A gram-negative, motile, strictly aerobic, and rod-shaped bacterium designated 176GS2-150T was isolated from the sponge Hymeniacidon sinapium. The taxonomic position of the novel isolate was confirmed using the polyphasic approach. Strain 176GS2-150T grew well at 25 °C on marine agar. Based on its 16S rRNA gene sequence, we showed that strain 176GS2-150T belongs to the family Psychromonadaceae and class Gammaproteobacteria and is related to Corallincola platygyrae JLT2006T (96.84% sequence similarity). The G + C content of the genomic DNA was 49.0 mol%. The assembled draft genome of strain 176GS2-150T was 4.2 Mbp and consisted of 14 contigs. The major respiratory quinone was Q-8, and the major fatty acids were summed feature 3 (comprising C16 :1ω6c and/or C16:1ω7c), summed feature 8 (comprising C18 :1ω7c and/or C18:1ω6c), C17:0 iso, C16:0, and C15:0 iso. The polar lipids were phosphatidylglycerol, phosphatidylethanolamine, 3 unidentified phospholipids, and 1 unidentified polar lipid. On the basis of the genotypic and phenotypic characteristics, strain 176GS2-150T can be placed as a new species within the genus Corallincola; the name Corallincola spongiicola sp. nov. has been proposed, with type strain 176GS2-150T (= KACC 19890T = LMG 31317T).

Litorilituus lipolyticus sp. nov., isolated from intertidal sand of the Yellow Sea in China, and emended description of Colwellia asteriadis.

A Gram-stain negative, rod-shaped, aerobic, oxidase-positive and catalase-weakly positive bacterial strain with polar or subpolar flagellum, designated RZ04T, was isolated from an intertidal sand sample collected from a coastal area of the Yellow Sea, China. The organism was observed to grow optimally at 25 °C and pH 6.5-7.0 with 2% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain RZ04T was closely related to Colwellia asteriadis (similarity 96.9%) and Litorilituus sediminis (similarity 96.8%), and 94.4-96.4% sequence similarities to other type strains of species of the genera belonged to the family Colwelliaceae. The dominant fatty acids of strain RZ04T were determined to be C17:1ω8c, C15:1ω8c, C16:0 and summed feature 3 (C16:1ω6c and/or C16:1ω7c), and the predominant isoprenoid quinone was determined to be quinone 8 (Q-8). Phosphatidylethanolamine, phosphatidylglycerol, an unidentified aminophospholipid and four unidentified lipids were determined to be the major constituents of the polar lipids. The genome of strain RZ04T is 4.14 Mbp with a G + C content of 37.4 mol%. A total of 3631 genes are predicted, with 3531 protein-coding genes, 75 RNA genes and 25 pseudogenes. Based on phenotypic, genotypic and phylogenetic analysis, strain RZ04T is considered to represent a novel species in the genus Litorilituus, for which the name Litorilituus lipolyticus is proposed. The type strain is RZ04T (= MCCC 1K03616T = KCTC 62835T). An emended description of Colwellia asteriadis is also provided.

Colistin Resistance in Enterobacterales Strains - A Current View.

Colistin is a member of cationic polypeptide antibiotics known as polymyxins. It is widely used in animal husbandry, plant cultivation, animal and human medicine and is increasingly used as one of the last available treatment options for patients with severe infections with carbapenem-resistant Gram-negative bacilli. Due to the increased use of colistin in treating infections caused by multidrug-resistant (MDR) bacteria, the resistance to this antibiotic ought to be monitored. Bacterial resistance to colistin may be encoded on transposable genetic elements (e.g. plasmids with the mcr genes). Thus far, nine variants of the mcr gene, mcr-1 - mcr-9, have been identified. Chromosomal resistance to colistin is associated with the modification of lipopolysaccharide (LPS). Various methods, from classical microbiology to molecular biology methods, are used to detect the colistin-resistant bacterial strains and to identify resistance mechanisms. The broth dilution method is recommended for susceptibility testing of bacteria to colistin.Colistin is a member of cationic polypeptide antibiotics known as polymyxins. It is widely used in animal husbandry, plant cultivation, animal and human medicine and is increasingly used as one of the last available treatment options for patients with severe infections with carbapenem-resistant Gram-negative bacilli. Due to the increased use of colistin in treating infections caused by multidrug-resistant (MDR) bacteria, the resistance to this antibiotic ought to be monitored. Bacterial resistance to colistin may be encoded on transposable genetic elements (e.g. plasmids with the mcr genes). Thus far, nine variants of the mcr gene, mcr-1 ­ mcr-9, have been identified. Chromosomal resistance to colistin is associated with the modification of lipopolysaccharide (LPS). Various methods, from classical microbiology to molecular biology methods, are used to detect the colistin-resistant bacterial strains and to identify resistance mechanisms. The broth dilution method is recommended for susceptibility testing of bacteria to colistin.