Does a Diet Rich in the Bacterium Rhodopirellula rubra Improve Daphnia magna Performance?

BACKGROUND: In the wild various organisms contribute to daphnids diet. This study, intendeds to evaluate the potential of the concentration of Rhodopirellula rubra as a single or supplementary food source for Daphnia magna. METHODS: Feeding assays were performed according to standard guidelines for chronic assays (21 days), and life-history parameters and several biomarkers (protein content, oxidative stress, energetic reserves and pigments) were measured. Five food regimens were conducted with 20 individual replicates (A - R. subcapitata; 0.2 - suspension of R. rubra at 0.2 arbitrary units (AU); 0.4 - suspension of R. rubra at 0.4 AU; 0.2+A - suspension of R. rubra at 0.2+alga; 0.2+A-suspension of R. rubra at 0.4 AU + alga). Additionally, the effects of three diets (A, 0.2, and 0.2+A) on the longevity of D. magna were assessed. RESULTS: The five diets showed a different C, N, and carotenoids composition, with an increase in the mixed diets. The results confirmed that the mixed diets improved D. magna life-history parameters. A decrease in glycogen, and the increase of haemoglobin, protein, and gluthione-S-transferase (GST) were observed. Furthermore, D. magna fed with bacterial single diets, presented worsen life history parameters and a decrease in the protein content. An induction of oxidative stress response (increased catalase and GST), and a significant decrease in lipid peroxidation and an accumulation of glycogen and carotenoids were observed. Overall, an increase in the amount of R. rubra provided to D. magna, from 0.2 AU to 0.4 AU, negatively impacted daphnid performance. No significant effects on Daphnia longevity (a 110-day assay) were observed among the three diets tested. However, a significant survival percentage and fertility (cumulative offspring is more than twice) was observed when D. magna was fed with the mixed diet. CONCLUSIONS: Results demonstrated that different diets provided a nutritional diversified food to the daphnids that induced differences in D. magna performance. The mixed diets proved to be beneficial (with increase in offspring) on D. magna performance, independently of the bacterial concentration tested. When in single diet, bacterial concentration is not nutritionally sufficient to raise D. magna even when in increased concentration.

Anatilimnocola floriformis sp. nov., a novel member of the family Pirellulaceae from a boreal lake, and emended description of the genus Anatilimnocola.

Planctomycetes of the family Pirellulaceae are commonly addressed as budding aquatic bacteria with a complex lifestyle. Although this family is well represented by cultured and taxonomically characterized isolates, nearly all of them were obtained from brackish or marine habitats. The examples of described freshwater Pirellulaceae planctomycetes are limited to two species only, Pirellula staley and 'Anatilimnocola aggregata'. In this study, we characterized a novel freshwater planctomycete of the genus 'Anatilimnocola', strain PX40T, which was isolated from a boreal eutrophic lake. Strain PX40T was represented by budding, unpigmented, ellipsoidal to pear-shaped cells, which often occurred in characteristic flower-like rosettes. Cells were covered by bundles of fimbriae; crateriform-like structures were localized on a reproductive cell pole only. These planctomycetes were obligately aerobic, heterotrophic bacteria that utilized various sugars and some polysaccharides, and were highly sensitive to NaCl. Growth occurred in the pH range 5.0-7.5 (with an optimum at pH 6.5-7.0), and at temperatures between 15 and 30 °C (with an optimum at 22-25 °C). The major fatty acids of strain PX40T were C18:1ω9c, C16:0, and 16:1ω7c; cells also contained a wide variety of hydroxy- and dihydroxy-fatty acids and a C31:9 alkene. The major intact polar lipids were diacylglyceryl-(N,N,N)-trimethylhomoserines. The 16S rRNA gene sequence of strain PX40T displayed 96.6% similarity to that of 'Anatilimnocola aggregata' ETA_A8T. The genome of strain PX40T was 8.93 Mb in size and contained one copy of rRNA operon, 76 tRNA genes and 7092 potential protein-coding genes. The DNA G+C content was 57.8%. The ANI value between strain PX40T and 'Anatilimnocola aggregata' ETA_A8T was 78.3%, suggesting that these planctomycetes represent distinct species. We, therefore, propose a novel species of the genus 'Anatilimnocola', 'A. floriformis' sp. nov., with strain PX40T (= KCTC 92369T = VKM B-3621T = UQM 41463T) as the type strain.

Targeted metagenome sequencing reveals the abundance of Planctomycetes and Bacteroidetes in the rhizosphere of pomegranate.

Agricultural productivity of pomegranate can be enhanced by identifying the crop-associated microbial diversity in the rhizosphere region with respect to plant growth promoters and other beneficial organisms. Traditional culture methods have limitations in microbial screening as only 1-2% of these organisms can be cultured. In the present study, 16S rRNA amplicon-based metagenomics approach using MinION Oxford Nanopore platform was employed to explore the microbial diversity in the rhizosphere of pomegranate Bhagwa variety, across variable soil depths from 0 to 5 cms (R2), 5-10 cms (R4) and 10-15 cms (R6), using bulk soil as the control. Across all the three layers, significant variations in pH, nitrogen content and total fungal count were observed. 16S rRNA analysis showed the abundance of planctomycetes, Pirellula staleyi, followed by bacteroidetes, Flavisolibacter LC59 and Niastella koreensis across the various soil depths in the rhizospheric soil samples. Pathway prediction analysis indicated arginine and proline metabolism (gamma-glutamyl putrescine oxidase) and hydrogen sulfide biosynthesis as the most abundant pathway hits. Comparative abundance analysis across layers showed the R6 layer with the maximum microbial diversity in terms of highest dimension of variation (79.2%) followed by R4 and R2 layers (p < 0.01). Our analysis shows the significant influence of root zone in shaping microbial diversity. This study has reported the presence of Planctomycetes, Pirellula staleyi for the first time in the pomegranate field.

Isolation, diversity and antimicrobial activity of planctomycetes from the Tejo river estuary (Portugal).

The discovery of new bioactive compounds is an invaluable aid to the development of new drugs. Strategies for finding novel molecules can focus on the exploitation of less studied organisms and ecosystems such as planctomycetes and brackish habitats. The unique cell biology of the underexplored Planctomycetota mean it is of particular interest. In this study, we aimed to isolate planctomycetes from the estuary of the Tejo river (Portugal). To reach this goal, macroalgae, water and sediments were sampled and diverse media and isolation techniques applied. Sixty-nine planctomycetal strains were brought into pure culture. An analysis of the 16S rRNA genes found that the majority of the isolates were affiliated to the genus Rhodopirellula. Putative novel taxa belonging to genera Stieleria and Rhodopirellula were also isolated and characterized morphologically. Enterobacterial repetitive intergenic consensus fingerprinting analyses showed higher diversity and different genotypes within close strains. Relevant biosynthetic gene clusters were found in most isolates and acetone extracts from representative strains exhibited mild antimicrobial activities against Escherichia coli and Staphylococcus aureus. Our work has not only enlarged the number and diversity of cultured planctomycetes but has also shown the potential for the discovery of bioactive compounds from the novel taxa.

A genomic overview including polyphasic taxonomy of Thalassoroseus pseudoceratinae gen. nov., sp. nov. isolated from a marine sponge, Pseudoceratina sp.

A pink-coloured, salt- and alkali-tolerant planctomycetal strain (JC658T) with oval to pear-shaped, motile, aerobic, Gram-negative stained cells was isolated from a marine sponge, Pseudoceratina sp. Strain JC658T shares the highest 16S rRNA gene sequence identity with Maioricimonas rarisocia Mal4T (< 89.2%) in the family Planctomycetaceae. The genomic analysis of the new strain indicates its biotechnological potential for the production of various industrially important enzymes, notably sulfatases and carbohydrate-active enzymes (CAZymes), and also potential antimicrobial compounds. Several genes encoding restriction-modification (RM) and CRISPR-CAS systems are also present. NaCl is obligate for growth, of which strain JC658T can tolerate a concentration up to 6% (w/v). Optimum pH and temperature for growth are 8.0 (range 7.0-9.0) and 25 ºC (range 10-40 °C), respectively. The major respiratory quinone of strain JC658T is MK6. Major fatty acids are C16:1ω7c/C16:1ω6c, C18:0 and C16:0. Major polar lipids are phosphatidylcholine, phosphatidyl-dimethylethanolamine and phosphatidyl-monomethylethanolamine. The genomic size of strain JC658T is 7.36 Mb with a DNA G + C content of 54.6 mol%. Based on phylogenetic, genomic (ANI, AAI, POCP, dDDH), chemotaxonomic, physiological and biochemical characteristics, we conclude that strain JC658T belongs to a novel genus and constitutes a novel species within the family Planctomycetaceae, for which we propose the name Thalassoroseus pseudoceratinae gen. nov., sp. nov. The novel species is represented by the type strain JC658T (= KCTC 72881 T = NBRC 114371 T).

Complete genome sequence of the cellulolytic planctomycete Telmatocola sphagniphila SP2T and characterization of the first cellulolytic enzyme from planctomycetes.

Planctomycetes of the family Gemmataceae are strictly aerobic chemo-organotrophs that display a number of hydrolytic capabilities. A member of this family, Telmatocola sphagniphila SP2T, is the first described planctomycete with experimentally proven ability for growth on cellulose. In this study, the complete genome sequence of strain SP2T was obtained and the genome-encoded determinants of its cellulolytic potential were analyzed. The T. sphagniphila SP2T genome was 6.59 Mb in size and contained over 5200 potential protein-coding genes. The search for enzymes that could be potentially involved in cellulose degradation identified a putative cellulase that contained a domain from the GH44 family of glycoside hydrolases. Homologous enzymes were also revealed in the genomes of two other Gemmataceae planctomycetes, Zavarzinella formosa A10T and Tuwongella immobilis MBLW1T. The gene encoding this predicted cellulase in strain SP2T was expressed in E. coli and the hydrolytic activity of the recombinant enzyme was confirmed in tests with carboxymethyl cellulose but not with crystalline cellulose, xylan, mannan or laminarin. This is the first experimentally characterized cellulolytic enzyme from planctomycetes.

Phylo-taxogenomics of the genus Tautonia with descriptions of Tautonia marina sp. nov., Tautonia rosea sp. nov., and emended description of the genus.

Four strains of Planctomycetes, (JC636, JC649, JC650T, JC657T) which are all salt and alkali tolerant, pink coloured, with spherical to oval shaped, Gram-stain-negative, non-motile cells were isolated from different regions of Chilika lagoon, India. All strains have obligate requirement for N-acetylglucosamine (NAG) and share highest 16S rRNA gene sequence identity with members of the genus Tautonia (<95%) of the family Isosphaeraceae. The 16S rRNA gene sequence identity between strains was >99.5%. Respiratory quinone for all the strains was MK6. Major fatty acids of all the strains were C18:1ω9c, C16:0 and C18:0. Major polar lipid of the strain JC650T was phosphatidylethanolamine, while, phosphatidylcholine and phosphatidylglycerol for strain JC657T. Spermidine was the only common polyamine for all the four strains. Strains JC657T, JC636 and JC649 shared highest phenotypic similarity along with 100% 16S rRNA gene sequence identity. Strains JC657T, JC636 and JC649 differed from strain JC650T phenotypically, chemotaxonomically and genotypically, thus belong to a different species. The genomic size of strain JC650T and JC657T are 7.06 Mb and 6.96 Mb with DNA G + C content of 63.9 and 62.7 mol%, respectively. Based on phylogenetic, genomic (ANI, AAI, POCP, dDDH), chemotaxonomic, physiological and biochemical characteristics, we conclude that strains JC650T and JC657T (together with strains JC636, JC649) belong to the genus Tautonia and constitute two novel species for which we propose the names Tautonia marina sp. nov., and Tautonia rosea sp. nov., respectively. These two novel species are represented by the type strains JC650T (=KCTC 72177T = NBRC 113885T) and JC657T (=KCTC 72597T = NBRC 113883T) respectively.

Aquisphaera insulae sp. nov., a new member in the family Isosphaeraceae, isolated from the floating island of Loktak lake and emended description of the genus Aquisphaera.

Strain JC669T was isolated from a floating island of Loktak lake, Manipur, India and shares the highest 16S rRNA gene sequence identity with Aquisphaera giovannonii OJF2T. The novel strain is aerobic, Gram negative, light pink-coloured, non-motile, NaCl intolerant and spherical to oval-shaped. It grows in the form of single cells or aggregates and possibly forms structures which appear like fruiting bodies. Strain JC669T grows well up to pH 9.0.The isolate produces MK-6 as respiratory quinone, C18:1ω9c, C16:0 and C18:0 as major fatty acids and phosphatidylcholine, an unidentified amino lipid, an unidentified choline lipid (UCL) and six additional unidentified lipids (UL1, 2, 3, 4, 5, 6) as polar lipids. Strain JC669T has a large genome size of 10.04 Mb and the genomic G + C content was 68.5 mol%. The genome contained all genes essential for lycopene related carotenoid biosynthesis. The polyphasic analysis of its phylogenetic position, morphological, physiological and genomic features supports the classification of strain JC669T as a novel species of the genus Aquisphaera, for which we propose the name Aquisphaera insulae sp. nov. Strain JC669T (= KCTC 72672T = NBRC 114306T) is the type strain of the novel species.

Heterologous Expression of Thermogutta terrifontis Endo-Xanthanase in Penicillium verruculosum, Isolation and Primary Characterization of the Enzyme.

Heterologous endo-xanthanase (EX) from the thermophilic planktomycete Thermogutta terrifontis strain was obtained using Penicillium verruculosum 537 (ΔniaD) expression system with the cellobiohydrolase 1 gene promoter. Homogeneous EX with a molecular weight of 23.7 kDa (pI 6.5) was isolated using liquid chromatography methods. This xanthan degrading enzyme also possesses the enzymatic activity towards CM-cellulose, ß-glucan, curdlan, lichenan, laminarin, galactomannan, xyloglucan but not towards p-nitrophenyl derivatives of ß-D-glucose, mannose and cellobiose. The temperature and pH optima of EX were 55°C and 4.0, respectively; the enzyme exhibited 90% of its maximum activity in the temperature range 50-60°C and pH 3-5.

Genomic analysis reveals the potential for hydrocarbon degradation of Rhodopirellula sp. MGV isolated from a polluted Brazilian mangrove.

Planctomycetes are bacteria found in several environments, such as mangroves. In the coastline of the State of Sao Paulo (Brazilian Southeast), mangroves occur in different stages of environmental contamination, promoted by the proximity to the city and industrial activities. One of these mangroves (located in the city of Bertioga) is characterized by the high impact due to past petroleum and ongoing urban contamination. We isolated five bacteria affiliated to Planctomycetes from this mangrove and further subjected them to phenotypical and genetic analysis. The tolerance for salinity was demonstrated by the cultivation under distinct concentrations of NaCl. The ability of this bacterium to use diverse carbon sources was revealed by the use of 30 C-sources from a total of 31 tests. We found the isolate Rhodopirellula sp. MGV very closely affiliated to species of the genus Rhodopirellula, harboring a genome with 7.16 Mbp and 55.3% of GC. The annotation of the 77 contigs resulted in 6.284 CDS, with a remarkable occurrence of sequences associated with aromatic carbon metabolism. In conclusion, we present the isolation and characterization of a Planctomycetes from mangroves, suggesting its participation in the degradation of hydrocarbons present in the contaminated mangroves studied.

Comparison of neutral lipid fatty acid composition in organisms from different trophic levels.

The profiles of total fatty acids (TFAs) and the neutral lipid fatty acids (NLFAs) were compared for the bacterium Rhodopirellula rubra and the alga Raphidocelis subcapitata (conventional food source for Daphnia magna). D. magna NLFAs were assessed when this crustacean was fed with bacterium and alga, individually or in combination. After NLFA extraction, the profiles of the various organisms were characterized by gas chromatography. Results evidenced the relevance of the different composition of the fatty acid (FAs) fractions in the different organisms, R. rubra and R. subcapitata. In these species, the NFLA analyses revealed high amounts of long chain FAs (C19). The FA profile of D. magna was influenced by the different diets provided although the preferred diet was the alga. D. magna showed the capacity to adapt to the available food resources as it defines its FA profile according to its needs, namely for the long chain FAs (C19).

"Candidatus Laterigemmans baculatus" gen. nov. sp. nov., the first representative of rod shaped planctomycetes with lateral budding in the family Pirellulaceae.

Two axenic cultures of Planctomycetes were isolated from distinct geographical regions of the east coast of India. The two closely related strains (JC640 and CH01) showed <93.3% 16S rRNA gene sequence identity with members of the genus Roseimaritima followed by Rhodopirellula (<91%). Both strains displayed non-canonical cell morphology of Planctomycetes, such as rod shaped cells with division by lateral budding. Both strains showed crateriform structures on their surfaces and cells lack fimbriae. The genomes have a size of about 5.76 Mb and DNA G+C content of 63.6mol%. Phylogenetic analysis based on 16S rRNA gene sequence and 92 core genes based RAxML phylogenetic tree place both the strains in the family Pirellulaceae and indicated Roseimaritima sediminicola as their closest relative. The AAI and POCP values differentiate both strains from rest of the members of the family Pirellulaceae. The axenic cultures of both strains were able to grow up to 8-10 passages and subsequently the cells became non-viable with pleomorphic shapes. Supported by genomic, phylogenetic and morphological differences, we conclude that both strains belong to a novel genus. However, since the new isolates lost their viability on passaging, we propose the novel genus as "Candidatus Laterigemmans" gen. nov. and the novel species as "Candidatus Laterigemmans baculatus" sp. nov.

Characterization of a nitrite-reducing octaheme hydroxylamine oxidoreductase that lacks the tyrosine cross-link.

The hydroxylamine oxidoreductase (HAO) family consists of octaheme proteins that harbor seven bis-His ligated electron-transferring hemes and one 5-coordinate catalytic heme with His axial ligation. Oxidative HAOs have a homotrimeric configuration with the monomers covalently attached to each other via a unique double cross-link between a Tyr residue and the catalytic heme moiety of an adjacent subunit. This cross-linked active site heme, termed the P460 cofactor, has been hypothesized to modulate enzyme reactivity toward oxidative catalysis. Conversely, the absence of this cross-link is predicted to favor reductive catalysis. However, this prediction has not been directly tested. In this study, an HAO homolog that lacks the heme-Tyr cross-link (HAOr) was purified to homogeneity from the nitrite-dependent anaerobic ammonium-oxidizing (anammox) bacterium Kuenenia stuttgartiensis, and its catalytic and spectroscopic properties were assessed. We show that HAOr reduced nitrite to nitric oxide and also reduced nitric oxide and hydroxylamine as nonphysiological substrates. In contrast, HAOr was not able to oxidize hydroxylamine or hydrazine supporting the notion that cross-link-deficient HAO enzymes are reductases. Compared with oxidative HAOs, we found that HAOr harbors an active site heme with a higher (at least 80 mV) midpoint potential and a much lower degree of porphyrin ruffling. Based on the physiology of anammox bacteria and our results, we propose that HAOr reduces nitrite to nitric oxide in vivo, providing anammox bacteria with NO, which they use to activate ammonium in the absence of oxygen.

A Thermophilic Bacterial Esterase for Scavenging Nerve Agents: A Kinetic, Biophysical and Structural Study.

Organophosphorous nerve agents (OPNA) pose an actual and major threat for both military and civilians alike, as an upsurge in their use has been observed in the recent years. Currently available treatments mitigate the effect of the nerve agents, and could be vastly improved by means of scavengers of the nerve agents. Consequently, efforts have been made over the years into investigating enzymes, also known as bioscavengers, which have the potential either to trap or hydrolyze these toxic compounds. We investigated the previously described esterase 2 from Thermogutta terrifontis (TtEst2) as a potential bioscavenger of nerve agents. As such, we assessed its potential against G-agents (tabun, sarin, and cyclosarin), VX, as well as the pesticide paraoxon. We report that TtEst2 is a good bioscavenger of paraoxon and G-agents, but is rather slow at scavenging VX. X-ray crystallography studies showed that TtEst2 forms an irreversible complex with the aforementioned agents, and allowed the identification of amino-acids, whose mutagenesis could lead to better scavenging properties for VX. In conjunction with its cheap production and purification processes, as well as a robust structural backbone, further engineering of TtEst2 could lead to a stopgap bioscavenger useful for in corpo scavenging or skin decontamination.

Descriptions of Roseiconus nitratireducens gen. nov. sp. nov. and Roseiconus lacunae sp. nov.

Two pink-coloured, oxidase-catalase-positive, salt and alkali-tolerant planctomycetal strains (JC635T and JC645T) with pear to spherical-shaped, Gram-stain-negative, motile cells were isolated from Chilika lagoon, India. Both strains share highest 16S rRNA gene sequence identity with members of the genus Rhodopirellula (< 94%) and Roseimaritima (< 94%) of the family Pirellulaceae. The 16S rRNA sequence identity between the strains JC635T and JC645T is 96.1%. Respiratory quinone for both strains is MK6. Major fatty acids are C18:1ω9c and C16:0. Major polar lipids are phosphatidylethanolamine, phosphatidylcholine, unidentified amino lipids and an unidentified lipid. The genomic size of strain JC635T and JC645T are 7.95 Mb and 8.2 Mb with DNA G + C content of 55.1 and 60.0 mol%, respectively. Based on phylogenetic, genomic (ANI, AAI, POCP, dDDH), chemotaxonomic, physiological and biochemical characteristics, we conclude that both strains belong to a novel genus Roseiconus gen. nov. and constitute two novel species for which we propose the names Roseiconus nitratireducens sp. nov. and Roseiconus lacunae sp. nov. The two novel species are represented by the type strains JC645T (= KCTC 72174T = NBRC 113879T) and JC635T (= KCTC 72164T = NBRC 113875T), respectively.

Moonlighting Biochemistry of Cysteine Synthase: A Species-specific Global Regulator.

Cysteine Synthase (CS), the enzyme that synthesizes cysteine, performs non-canonical regulatory roles by binding and modulating functions of disparate proteins. Beyond its role in catalysis and regulation in the cysteine biosynthesis pathway, it exerts its moonlighting effect by binding to few other proteins which possess a C-terminal "CS-binding motif", ending with a terminal ILE. Therefore, we hypothesized that CS might regulate many other disparate proteins with the "CS-binding motif". In this study, we developed an iterative sequence matching method for mapping moonlighting biochemistry of CS and validated our prediction by analytical and structural approaches. Using a minimal protein-peptide interaction system, we show that five previously unknown CS-binder proteins that participate in diverse metabolic processes interact with CS in a species-specific manner. Furthermore, results show that signatures of protein-protein interactions, including thermodynamic, competitive-inhibition, and structural features, highly match the known CS-Binder, serine acetyltransferase (SAT). Together, the results presented in this study allow us to map the extreme multifunctional space (EMS) of CS and reveal the biochemistry of moonlighting space, a subset of EMS. We believe that the integrated computational and experimental workflow developed here could be further modified and extended to study protein-specific moonlighting properties of multifunctional proteins.

Ecological memory of recurrent drought modifies soil processes via changes in soil microbial community.

Climate change is altering the frequency and severity of drought events. Recent evidence indicates that drought may produce legacy effects on soil microbial communities. However, it is unclear whether precedent drought events lead to ecological memory formation, i.e., the capacity of past events to influence current ecosystem response trajectories. Here, we utilize a long-term field experiment in a mountain grassland in central Austria with an experimental layout comparing 10 years of recurrent drought events to a single drought event and ambient conditions. We show that recurrent droughts increase the dissimilarity of microbial communities compared to control and single drought events, and enhance soil multifunctionality during drought (calculated via measurements of potential enzymatic activities, soil nutrients, microbial biomass stoichiometry and belowground net primary productivity). Our results indicate that soil microbial community composition changes in concert with its functioning, with consequences for soil processes. The formation of ecological memory in soil under recurrent drought may enhance the resilience of ecosystem functioning against future drought events.

Short-Term Exposure to High-Temperature Water Causes a Shift in the Microbiome of the Common Aquarium Sponge Lendenfeldia chondrodes.

Marine sponges harbor diverse microbiomes that contribute to their energetic and metabolic needs. Although numerous studies on sponge microbial diversity exist, relatively few focused on sponge microbial community changes under different sources of environmental stress. In this study, we assess the impact of elevated seawater temperature on the microbiome of cultured Lendenfeldia chondrodes, a coral reef sponge commonly found in marine aquaria. Lendenfeldia chondrodes exhibits high thermal tolerance showing no evidence of tissue damage or bleaching at 5 °C above control water temperature (26 °C). High-throughput sequencing of the bacterial 16S rRNA V4 region revealed a response of the microbiome of L. chondrodes to short-term exposure to elevated seawater temperature. Shifts in abundance and richness of the dominant bacterial phyla found in the microbiome of this species, namely Proteobacteria, Cyanobacteria, Planctomycetes, and Bacteroidetes, characterized this response. The observed resilience of L. chondrodes and the responsiveness of its microbiome to short-term increases in seawater temperature suggest that this holobiont may be capable of acclimating to anthropogenic-driven sublethal environmental stress via a re-accommodation of its associated bacterial community. This sheds a new light on the potential for resilience of some sponges to increasing surface seawater temperatures and associated projected regime shifts in coral reefs.

Additions to the genus Gimesia: description of Gimesia alba sp. nov., Gimesia algae sp. nov., Gimesia aquarii sp. nov., Gimesia aquatilis sp. nov., Gimesia fumaroli sp. nov. and Gimesia panareensis sp. nov., isolated from aquatic habitats of the Northern Hemisphere.

Thirteen novel planctomycetal strains were isolated from five different aquatic sampling locations. These comprise the hydrothermal vent system close to Panarea Island (Italy), a biofilm on the surface of kelp at Monterey Bay (CA, USA), sediment and algae on Mallorca Island (Spain) and Helgoland Island (Germany), as well as a seawater aquarium in Braunschweig, Germany. All strains were shown to belong to the genus Gimesia. Their genomes cover a size range from 7.22 to 8.29 Mb and have a G+C content between 45.1 and 53.7%. All strains are mesophilic (Topt 26-33 °C) with generation times between 12 and 32 h. Analysis of fatty acids yielded palmitic acid (16:0) and a fatty acid with the equivalent chain length of 15.817 as major compounds. While five of the novel strains belong to the already described species Gimesia maris and Gimesia chilikensis, the other strains belong to novel species, for which we propose the names Gimesia alba (type strain Pan241wT = DSM 100744T = LMG 31345T = CECT 9841T = VKM B-3430T), Gimesia algae (type strain Pan161T = CECT 30192T = STH00943T = LMG 29130T), Gimesia aquarii (type strain V144T = DSM 101710T = VKM B-3433T), Gimesia fumaroli (type strain Enr17T = DSM 100710T = VKM B-3429T) and Gimesia panareensis (type strain Enr10T = DSM 100416T = LMG 29082T). STH numbers refer to the Jena Microbial Resource Collection (JMRC).