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Deep underground galleries are used to access the deep biosphere in addition to mining and other engineering applications, such as geological disposal of radioactive waste. Fracture networks developed in the excavation damaged zone (EDZ) are concerned with accelerating mass transport, where microbial colonization might be possible due to the availability of space and nutrients. In this study, microbial biofilms at EDZ fractures were investigated by drilling from a 350-m-deep gallery and subsequent borehole logging at the Horonobe Underground Research Laboratory (URL). By using microscopic and spectroscopic techniques, the dense colonization of microbial cells was demonstrated at the surfaces of the EDZ fractures with high hydraulic conductivity. 16S rRNA gene sequence analysis revealed the dominance of gammaproteobacterial lineages, the cultivated members of which are aerobic methanotrophs. The near-complete genomes from Horonobe groundwater, affiliated with the methanotrophic lineages, were fully equipped with genes involved in aerobic methanotrophy. Although the mediation of aerobic methanotrophy remains to be demonstrated, microbial O 2 production was supported by the presence of genes in the near-complete genomes, such as catalase and superoxide dismutase that produce O 2 from reactive oxygen species and a nitric oxide reductase gene with the substitutions of amino acids in motifs. It is concluded that the EDZ fractures provide energetically favorable subsurface habitats for microorganisms., (© 2024. The Author(s).)

As the closest living relatives of animals, choanoflagellates offer insights into the ancestry of animal cell physiology. Here, we report the isolation and characterization of a colonial choanoflagellate from Mono Lake, California. The choanoflagellate forms large spherical colonies that are an order of magnitude larger than those formed by the closely related choanoflagellate Salpingoeca rosetta . In cultures maintained in the laboratory, the lumen of the spherical colony is filled with a branched network of extracellular matrix and colonized by bacteria, including diverse Gammaproteobacteria and Alphaproteobacteria. We propose to erect Barroeca monosierra gen. nov., sp. nov. Hake, Burkhardt, Richter, and King to accommodate this extremophile choanoflagellate. The physical association between bacteria and B. monosierra in culture presents a new experimental model for investigating interactions among bacteria and eukaryotes. Future work will investigate the nature of these interactions in wild populations and the mechanisms underpinning the colonization of B. monosierra spheres by bacteria., Importance: The diversity of organisms that live in the extreme environment of Mono Lake (California, USA) is limited. We sought to investigate whether the closest living relatives of animals, the choanoflagellates, exist in Mono Lake, a hypersaline, alkaline, arsenic-rich environment. We repeatedly isolated members of a new species of choanoflagellate, which we have named Barroeca monosierra . Characterization of B. monosierra revealed that it forms large spherical colonies containing diverse co-isolated bacteria, providing an opportunity to investigate mechanisms underlying physical associations between eukaryotes and bacteria., Competing Interests: The authors declare no conflict of interest.

A novel bacterium, designated as MI-G T , was isolated from marine sponge Diacarnu s erythraeanus . Cells of strain MI-G T are Gram-stain-negative, aerobic, and rod or coccoid-ovoid in shape. MI-G T is able to grow at 10-40 °C (optimum, 28 °C), with 1.0-8.0% (w/v) NaCl (optimum, 4.0%), and at pH 5.5-9.0 (optimum, pH 8.0). The 16S rRNA gene sequence of strain MI-G T shows 98.35, 97.32 and 97.25% similarity to those of Microbulbifer variabilis Ni-2088 T , Microbulbifer maritimus TF-17 T and Microbulbifer echini AM134 T , respectively. Phylogenetic analysis also exhibits that strain MI-G T falls within a clade comprising members of the genus Microbulbifer (class Gammaproteobacteria ). The genome size of strain MI-G T is 4478124 bp with a G+C content of 54.51 mol%. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain MI-G T and other type strains are 71.61-76.44% (ANIb), 83.27-84.36% (ANIm) and 13.4-18.7% (dDDH), respectively. These values are significantly lower than the recommended threshold values for bacterial species delineation. Percentage of conserved proteins and average amino acid identity values among the genomes of strain MI-G T and other closely related species are 52.04-59.13% and 67.47-77.21%, respectively. The major cellular fatty acids of MI-G T are composed of summed feature 8 (C 18 : 1 ω 7 c or C 18 : 1 ω 6 c ), iso-C 11 : 0 3-OH, iso-C 15 : 0 , C 16 : 0 , and summed feature 9 (C 17 : 1 iso ω 9 c or C 16 : 0 10-methyl). The polar lipids of MI-G T mainly consist of phosphatidylethanolamine, phosphatidylglycerol, aminolipid, and two glycolipids. The major respiratory quinone is Q-8. Based on differential phenotypic and phylogenetic data, strain MI-G T is considered to represent a novel species of genus Microbulbifer , for which the name Microbulbifer spongiae sp. nov. is proposed. The type strain is MI-G T (=MCCC 1K07826 T =KCTC 8081 T ).

Two endophytic bacterial strains, designated S1-1-2  T and S1-1-8, were isolated from the leaves of a mangrove plant, Avicennia marina. The isolates were Gram-stain-negative, motile, rod-shaped bacteria with lateral flagella. Growth occurred at 4-41 °C, pH 4.0-11.0, and 0.5-25.0% NaCl. The predominant fatty acids of the novel strains were C 18:1 ω6c/ω7c, C 19:0 cyclo ω8c, and C 16:0 . The predominant respiratory quinone was Q-9. The DNA G + C contents of strains S1-1-2  T and S1-1-8 analyzed by genome sequences were 63.8%. Phylogenetic analysis based on 16S rRNA gene sequences obtained using sanger sequencing and whole-genome phylogenetic analysis revealed an affiliation between the two strains and the genus Salinicola in the class Gammaproteobacteria. Detailed genotypic, chemotaxonomic, and phenotypic data support the conclusion that these two strains should be described as a novel species in the genus Salinicola. Here, Salinicola avicenniae sp. nov. (type strain S1-1-2  T  = LMG 32655  T  = MCCC 1A19027 T ) is proposed., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The high diversity and global distribution of heterotrophic bacterial diazotrophs (HBDs) in the ocean has recently become apparent. However, understanding the role these largely uncultured microorganisms play in marine N 2 fixation poses a challenge due to their undefined growth requirements and the complex regulation of the nitrogenase enzyme. We isolated and characterized Candidatus Thalassolituus haligoni, a member of a widely distributed clade of HBD belonging to the Oceanospirillales. Analysis of its nifH gene via amplicon sequencing revealed the extensive distribution of Cand. T. haligoni across the Pacific, Atlantic, and Arctic Oceans. Pangenome analysis indicates that the isolate shares >99% identity with an uncultured metagenome-assembled genome called Arc-Gamma-03, recently recovered from the Arctic Ocean. Through combined genomic, proteomic, and physiological approaches, we confirmed that the isolate fixes N 2 gas. However, the mechanisms governing nitrogenase regulation in Cand. T. haligoni remain unclear. We propose Cand. T. haligoni as a globally distributed, cultured HBD model species within this understudied clade of Oceanospirillales.

The genus Natronospira is represented by a single species of extremely salt-tolerant aerobic alkaliphilic proteolytic bacterium, isolated from hypersaline soda lakes. When cells of Gram-positive cocci were used as a substrate instead of proteins at extremely haloalkaline conditions, two new members of this genus were enriched and isolated in pure culture from the same sites. Strains AB-CW1 and AB-CW4 are obligate aerobic heterotrophic proteolytic bacteria able to feed on both live and dead cells of staphylococci and a range of proteins and peptides. Similar to the type species, N. proteinivora, the isolates are extremely salt-tolerant obligate alkaliphiles. However, N. proteinivora was unable to use bacterial cells as a substrate. Electron microscopy showed direct contact between the prey and predator cells. Functional analysis of the AB-CW1 and AB-CW4 genomes identified two sets of genes coding for extracellular enzymes potentially involved in the predation and proteolysis, respectively. The first set includes several copies of lysozyme-like GH23 peptidoglycan-lyase and murein-specific M23 [Zn]-di-peptidase enabling the cell wall degradation. The second set features multiple copies of secreted serine and metallopeptidases apparently allowing for the strong proteolytic phenotype. Phylogenomic analysis placed the isolates into the genus Natronospira as two novel species members, and furthermore indicated that this genus forms a deep-branching lineage of a new family (Natronospiraceae) and order (Natronospirales) within the class Gammaproteobacteria. On the basis of distinct phenotypic and genomic properties, strain AB-CW1 T (JCM 335396 = UQM 41579) is proposed to be classified as Natronospira elongata sp. nov., and AB-CW4 T (JCM 335397 = UQM 41580) as Natronospira bacteriovora sp. nov., (Copyright © 2024 The Author(s). Published by Elsevier GmbH.. All rights reserved.)

Background: Phytobacter diazotrophicus (P. diazotrophicus) is an opportunistic pathogen that causes nosocomial outbreaks and sepsis. However, there are no reports of P. diazotrophicus isolated from human blood in China., Case Presentation: A 27-day-old female infant was admitted to our hospital with fever and high bilirubin levels. The clinical features included jaundice, abnormal coagulation, cholestasis, fever, convulsions, weak muscle tension, sucking weakness, ascites, abnormal tyrosine metabolism, cerebral oedema, abnormal liver function, clavicle fracture, and haemolytic anaemia. The strain isolated from the patient's blood was identified as P. diazotrophicus by whole-genome sequencing (WGS). Galactosemia type 1 (GALAC1) was diagnosed using whole-exome sequencing (WES). Based on drug sensitivity results, 10 days of anti-infective treatment with meropenem combined with lactose-free milk powder improved symptoms., Conclusion: P. diazotrophicus was successfully identified in a patient with neonatal sepsis combined with galactosemia. Galactosemia may be an important factor in neonatal sepsis. This case further expands our understanding of the clinical characteristics of GALAC1., (© 2024. The Author(s).)

In coastal marine ecosystems, kelp forests serve as a vital habitat for numerous species and significantly influence local nutrient cycles. Bull kelp, or Nereocystis luetkeana, is a foundational species in the iconic kelp forests of the northeast Pacific Ocean and harbours a complex microbial community with potential implications for kelp health. Here, we report the isolation and functional characterisation of 16 Nereocystis-associated bacterial species, comprising 13 Gammaproteobacteria, 2 Flavobacteriia and 1 Actinomycetia. Genome analyses of these isolates highlight metabolisms potentially beneficial to the host, such as B vitamin synthesis and nitrogen retention. Assays revealed that kelp-associated bacteria thrive on amino acids found in high concentrations in the ocean and in the kelp (glutamine and asparagine), generating ammonium that may facilitate host nitrogen acquisition. Multiple isolates have genes indicative of interactions with key elemental cycles in the ocean, including carbon, nitrogen and sulphur. We thus report a collection of kelp-associated microbial isolates that provide functional insight for the future study of kelp-microbe interactions., (© 2024 The Authors. Environmental Microbiology Reports published by John Wiley & Sons Ltd.)

Antarctica, one of the most extreme environments on Earth, hosts diverse microbial communities. These microbes have evolved and adapted to survive in these hostile conditions, but knowledge on the molecular mechanisms underlying this process remains limited. The Italian Collection of Antarctic Bacteria ( Collezione Italiana Batteri Antartici (CIBAN)), managed by the University of Messina, represents a valuable repository of cold-adapted bacterial strains isolated from various Antarctic environments. In this study, we sequenced and analyzed the genomes of 58 marine Gammaproteobacteria strains from the CIBAN collection, which were isolated during Italian expeditions from 1990 to 2005. By employing genome-scale metrics, we taxonomically characterized these strains and assigned them to four distinct genera: Pseudomonas , Pseudoalteromonas , Shewanella, and Psychrobacter . Genome annotation revealed a previously untapped functional potential, including secondary metabolite biosynthetic gene clusters and antibiotic resistance genes. Phylogenomic analyses provided evolutionary insights, while assessment of cold-shock protein presence shed light on adaptation mechanisms. Our study emphasizes the significance of CIBAN as a resource for understanding Antarctic microbial life and its biotechnological potential. The genomic data unveil new horizons for insight into bacterial existence in Antarctica.

Deep-sea massive sulfide deposits serve as energy sources for chemosynthetic ecosystems in dark, cold environments even after hydrothermal activity ceases. However, the vertical distribution of microbial communities within sulfide deposits along their depth from the seafloor as well as their ecological roles remain unclear. We herein conducted a culture-independent metagenomic ana-lysis of a core sample of massive sulfide deposits collected in a hydrothermally inactive field of the Southern Mariana Trough, Western Pacific, by drilling (sample depth: 0.52‍ ‍m below the seafloor). Based on the gene context of the metagenome-assembled genomes (MAGs) obtained, we showed the metabolic potential of as-yet-uncultivated microorganisms, particularly those unique to the shallow zone rich in iron hydroxides. Some members of Gammaproteobacteria have potential for the oxidation of reduced sulfur species (such as sulfide and thiosulfate) to sulfate coupled to nitrate reduction to ammonia and carbon fixation via the Calvin-Benson-Bassham (CBB) cycle, as the primary producers. The Zetaproteobacteria member has potential for iron oxidation coupled with microaerobic respiration. A comparative ana-lysis with previously reported metagenomes from deeper zones (~2‍ ‍m below the seafloor) of massive sulfide deposits revealed a difference in the relative abundance of each putative primary producer between the shallow and deep zones. Our results expand knowledge on the ecological potential of uncultivated microorganisms in deep-sea massive sulfide deposits and provide insights into the vertical distribution patterns of chemosynthetic ecosystems.

The genomes of obligately host-restricted bacteria suffer from accumulating mildly deleterious mutations, resulting in marked size reductions. Psyllids (Hemiptera) are phloem sap-sucking insects with a specialized organ called the bacteriome, which typically harbors two vertically transmitted bacterial symbionts: the primary symbiont "Candidatus Carsonella ruddii" (Gammaproteobacteria) and a secondary symbiont that is phylogenetically diverse among psyllid lineages. The genomes of several Carsonella lineages were revealed to be markedly reduced (158-174‍ ‍kb), AT-rich (14.0-17.9% GC), and structurally conserved with similar gene inventories devoted to synthesizing essential amino acids that are scarce in the phloem sap. However, limited genomic information is currently available on secondary symbionts. Therefore, the present study investigated the genomes of the bacteriome-associated dual symbionts, Secondary_AM (Gammaproteobacteria) and Carsonella_AM, in the mulberry psyllid Anomoneura mori (Psyllidae). The results obtained revealed that the Secondary_AM genome is as small and AT-rich (229,822 bp, 17.3% GC) as those of Carsonella lineages, including Carsonella_AM (169,120 bp, 16.2% GC), implying that Secondary_AM is an evolutionarily ancient obligate mutualist, as is Carsonella. Phylogenomic ana-lyses showed that Secondary_AM is sister to "Candidatus Psyllophila symbiotica" of Cacopsylla spp. (Psyllidae), the genomes of which were recently reported (221-237‍ ‍kb, 17.3-18.6% GC). The Secondary_AM and Psyllophila genomes showed highly conserved synteny, sharing all genes for complementing the incomplete tryptophan biosynthetic pathway of Carsonella and those for synthesizing B vitamins. However, sulfur assimilation and carotenoid-synthesizing genes were only retained in Secondary_AM and Psyllophila, respectively, indicating ongoing gene silencing. Average nucleotide identity, gene ortholog similarity, genome-wide synteny, and substitution rates suggest that the Secondary_AM/Psyllophila genomes are more labile than Carsonella genomes.

The microbiome represents a complex network among the various members of the community of microorganisms that are associated with a host. The composition of the bacterial community is essential to supplement multiple metabolic pathways that the host lacks, particularly in organisms with blood-sucking habits such as ticks. On the other hand, some endosymbionts showed some competence with potentially pathogenic microorganisms. Francisella-like endosymbionts (FLEs) encompass a group of gamma-proteobacterias that are closely related to Francisella tularensis, but are usually apathogenic, which brings nutrients like vitamin B and other cofactors to the tick. It has been postulated that the main route of transmission of FLE is vertical; however, evidence has accumulated regarding the possible mechanism of horizontal transmission. Despite growing interest in knowledge of endosymbionts in the Neotropical region, the efforts related to the establishment of their inventory for tick communities are concentrated in South and Central America, with an important gap in knowledge in Mesoamerican countries such as Mexico. For this reason, the aim of this work was to evaluate the presence and diversity of endosymbionts in the highly host-specialized tick Amblyomma nodosum collected from the anteater Tamandua mexicana in Mexico. We analysed 36 A. nodosum for the presence of DNA of endosymbiont (Coxiella and Francisella) and pathogenic (Anaplasma, Borrelia, Ehrlichia and Rickettsia) bacteria. The presence of a member of the genus Francisella and Candidatus Anaplasma brasiliensis was demonstrated. Our findings provide information on the composition of A. nodosum's microbiome, increasing the inventory of bacterial species associated with this hard tick on the American continent., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Wildlife play a role in the acquisition, maintenance, and dissemination of antimicrobial resistance (AMR). This is especially true at the human-domestic animal-wildlife interface, like urbanized areas, where interactions occur that can promote the cross-over of AMR bacteria and genes. We conducted a 2-year fecal surveillance ( n  = 783) of a white-tailed deer (WTD) herd from an urban park system in Ohio to identify and characterize cephalosporin-resistant and carbapenemase-producing bacteria using selective enrichment. Using generalized linear mixed models we found that older (OR = 2.3, P  < 0.001), male (OR = 1.8, P  = 0.001) deer from urbanized habitats (OR = 1.4, P  = 0.001) were more likely to harbor extended-spectrum cephalosporin-resistant Enterobacterales. In addition, we isolated two carbapenemase-producing Enterobacterales (CPE), a Klebsiella quasipneumoniae harboring bla KPC-2 and an Escherichia coli harboring bla NDM-5 , from two deer from urban habitats. The genetic landscape of the plasmid carrying bla KPC-2 was unique, not clustering with other reported plasmids encoding KPC-2, and only sharing 78% of its sequence with its nearest match. While the plasmid carrying bla NDM-5 shared sequence similarity with other reported plasmids encoding NDM-5, the intact IS26 mobile genetic elements surrounding multiple drug resistant regions, including the bla NDM-5 , has been reported infrequently. Both carbapenemase genes were successfully conjugated to a J53 recipient conferring a carbapenem-resistant phenotype. Our findings highlight that urban environments play a significant role on the transmission of AMR bacteria and genes to wildlife and suggest WTD may play a role in the dissemination of clinically and epidemiologically relevant antimicrobial resistant bacteria. IMPORTANCE The role of wildlife in the spread of antimicrobial resistance is not fully characterized. Some wildlife, including white-tailed deer (WTD), can thrive in suburban and urban environments. This may result in the exchange of antimicrobial resistant bacteria and resistance genes between humans and wildlife, and lead to their spread in the environment. We found that WTD living in an urban park system carried antimicrobial resistant bacteria that were important to human health and resistant to antibiotics used to treat serious bacterial infections. This included two deer that carried bacteria resistant to carbapenem antibiotics which are critically important for treatment of life-threatening infections. These two bacteria had the ability to transfer their AMR resistance genes to other bacteria, making them a threat to public health. Our results suggest that WTD may contribute to the spread of antimicrobial resistant bacteria in the environment.

Decreased susceptibility to carbapenems in Enterobacterales is an emerging concern. Conventional methods with short turnaround times are crucial for therapeutic decisions and infection control. In the current study, we used the Xpert CARBA-R (Cepheid, Sunnyvale, CA, USA) and the NG-Test CARBA 5 (NG Biotech, Guipry, France) assays for carbapenemase detection in 214 carbapenem-resistant Enterobacterales (CRE) blood isolates. We used the modified carbapenem inactivation method, conventional PCR, and sequencing to determine the production of five common carbapenemase families and their subtypes. We performed wzc -genotyping for all CR-Klebsiella pneumoniae (CRKP) and multilocus sequence typing for all carbapenemase-producing CRE isolates to reveal their genetic relatedness. The results showed a sensitivity of 99.8% and a specificity of 100% by the Xpert assay, and a sensitivity of 100% and a specificity of 99% by the NG-Test in detecting carbapenemases of 84 CRKP isolates with only one (VIM-1+IMP-8) failure in both tests. For CR-Escherichia coli, four carbapenemase-producing isolates were detected accurately for their subtypes. The two major clones of carbapenemase-producing CRKP isolates in Taiwan were ST11-K47 producing KPC-2 ( n  = 47) and ST11-K64 producing OXA-48-like ( n  = 9). Our results support the use of either test in routine laboratories for the rapid detection of common carbapenemases. Caution should be taken using the Xpert assay in areas with a high prevalence of CRE carrying bla IMP-8 . IMPORTANCE Carbapenemase-producing Enterobacterales (CPE) are emerging worldwide, causing nosocomial outbreaks and even community-acquired infections since their appearance 2 decades ago. Our previous national surveillance of CPE isolates in Taiwan identified five carbapenemase families (KPC, OXA, NDM, VIM, and IMP) with the KPC-2 and OXA-48-like types predominant. Timely detection and classification of carbapenemases in CPE may be a useful test to guide optimal therapy and infection control. Genetic detection methods using the Xpert CARBA-R assay and the immunochromatographic assay using the NG-Test CARBA 5 have been validated with the advantage of short turnaround time. Our study demonstrated that the NG and Xpert assays are convenient methods to accurately identify carbapenemases in carbapenem-resistant Klebsiella pneumoniae and carbapenem-resistant Escherichia coli blood isolates. Detecting IMP variants remains challenging, and the results of Xpert CARBA-R assay should be carefully interpreted.

Rhodanobacter species dominate in the Oak Ridge Reservation (ORR) subsurface environments contaminated with acids, nitrate, metal radionuclides, and other heavy metals. To uncover the genomic features underlying adaptations to these mixed-waste environments and to guide genetic tool development, we sequenced the whole genomes of eight Rhodanobacter strains isolated from the ORR site. The genome sizes ranged from 3.9 to 4.2 Mb harboring 3,695 to 4,035 protein-coding genes and GC contents approximately 67%. Seven strains were classified as R. denitrificans and one strain, FW510-R12, as R. thiooxydans based on full length 16S rRNA sequences. According to gene annotation, the top two Cluster of Orthologous Groups (COGs) with high pan-genome expansion rates (Pan/Core gene ratio) were "replication, recombination and repair" and "defense mechanisms." The denitrifying genes had high DNA homologies except the predicted protein structure variances in NosZ. In contrast, heavy metal resistance genes were diverse with between 7 to 34% of them were located in genomic islands, and these results suggested origins from horizontal gene transfer. Analysis of the methylation patterns in four strains revealed the unique 5mC methylation motifs. Most orthologs (78%) had ratios of nonsynonymous to synonymous substitutions (dN/dS) less than one when compared to the type strain 2APBS1, suggesting the prevalence of negative selection. Overall, the results provide evidence for the important roles of horizontal gene transfer and negative selection in genomic adaptation at the contaminated field site. The complex restriction-modification system genes and the unique methylation motifs in Rhodanobacter strains suggest the potential recalcitrance to genetic manipulation. IMPORTANCE Despite the dominance of Rhodanobacter species in the subsurface of the contaminated Oak Ridge Reservation (ORR) site, very little is known about the mechanisms underlying their adaptions to the various stressors present at ORR. Recently, multiple Rhodanobacter strains have been isolated from the ORR groundwater samples from several wells with varying geochemical properties. Using Illumina, PacBio, and Oxford Nanopore sequencing platforms, we obtained the whole genome sequences of eight Rhodanobacter strains. Comparison of the whole genomes demonstrated the genetic diversity, and analysis of the long nanopore reads revealed the heterogeneity of methylation patterns in strains isolated from the same well. Although all strains contained a complete set of denitrifying genes, the predicted tertiary structures of NosZ differed. The sequence comparison results demonstrate the important roles of horizontal gene transfer and negative selection in adaptation. In addition, these strains may be recalcitrant to genetic manipulation due to the complex restriction-modification systems and methylations.

Characterization of the microbial community is essential for understanding the symbiotic relationships between microbes and host insects. Chrysomya megacephala is a vital resource, a forensic insect, a pollinator, and a vector for enteric bacteria, protozoa, helminths, and viruses. However, research on its microbial community is incomprehensive, particularly at the pupal stage, which comprises approximately half of the entire larval development stage and is important entomological evidence in forensic medicine. For the first time, this study investigated the bacterial communities of C. megacephala pupae at different ages using third-generation sequencing technology. The results showed that C. megacephala has a diverse and dynamic bacterial community. Cluster analysis at ≥ 97% similarity produced 154 operational taxonomic units (OTUs) that belonged to 10 different phyla and were distributed into 15 classes, 28 orders, 50 families, 88 genera, and 130 species. Overall, the number of bacterial OTUs increased with the development of pupae, and the relative abundance of Wolbachia in the Day5 group was significantly lower than that in the other groups. Within the pupal stage, Proteobacteria, Firmicutes, and Bacteroidetes were the dominant phyla of bacteria. At the genus level, Wolbachia and Ignatzschineria coexisted, a rarely known feature. In addition, we found Erysipelothrix rhusiopathiae, the etiological agent of swine erysipelas, which is rarely identified in insects. This study enriches the understanding of the microbial community of C. megacephala and provides a reference for better utilization and control of C. megacephala., (© 2022. The Author(s).)

Background: Psyllids (Hemiptera: Psylloidea) comprise a group of plant sap-sucking insects that includes important agricultural pests. They have close associations not only with plant pathogens, but also with various microbes, including obligate mutualists and facultative symbionts. Recent studies are revealing that interactions among such bacterial populations are important for psyllid biology and host plant pathology. In the present study, to obtain further insight into the ecological and evolutionary behaviors of bacteria in Psylloidea, we analyzed the microbiomes of 12 psyllid species belonging to the family Psyllidae (11 from Psyllinae and one from Macrocorsinae), using high-throughput amplicon sequencing of the 16S rRNA gene., Results: The analysis showed that all 12 psyllids have the primary symbiont, Candidatus Carsonella ruddii (Gammaproteobacteria: Oceanospirillales), and at least one secondary symbiont. The majority of the secondary symbionts were gammaproteobacteria, especially those of the family Enterobacteriaceae (order: Enterobacteriales). Among them, symbionts belonging to "endosymbionts3", which is a genus-level monophyletic group assigned by the SILVA rRNA database, were the most prevalent and were found in 9 of 11 Psyllinae species. Ca. Fukatsuia symbiotica and Serratia symbiotica, which were recognized only as secondary symbionts of aphids, were also identified. In addition to other Enterobacteriaceae bacteria, including Arsenophonus, Sodalis, and "endosymbionts2", which is another genus-level clade, Pseudomonas (Pseudomonadales: Pseudomonadaceae) and Diplorickettsia (Diplorickettsiales: Diplorickettsiaceae) were identified. Regarding Alphaproteobacteria, the potential plant pathogen Ca. Liberibacter europaeus (Rhizobiales: Rhizobiaceae) was detected for the first time in Anomoneura mori (Psyllinae), a mulberry pest. Wolbachia (Rickettsiales: Anaplasmataceae) and Rickettsia (Rickettsiales: Rickettsiaceae), plausible host reproduction manipulators that are potential tools to control pest insects, were also detected., Conclusions: The present study identified various bacterial symbionts including previously unexpected lineages in psyllids, suggesting considerable interspecific transfer of arthropod symbionts. The findings provide deeper insights into the evolution of interactions among insects, bacteria, and plants, which may be exploited to facilitate the control of pest psyllids in the future., (© 2022. The Author(s).)

A Gram-stain-negative, aerobic, rod-shaped and non-motile novel bacterial strain, designated MAH-13 T , was isolated from a soil sample. The colonies were observed to be yellow-coloured, smooth, spherical and 1.8-3.0 mm in diameter when grown on nutrient agar medium for 2 days. Strain MAH-13 T was found to be able to grow at 20-40 °C, at pH 5.0-10.0 and with 0-1.0% NaCl (w/v). Cell growth occurred on tryptone soya agar, Luria-Bertani agar, nutrient agar and Reasoner's 2A agar. The strain was found to be positive for both oxidase and catalase tests. The strain was positive for hydrolysis of casein, starch, DNA and l-tyrosine. According to 16S rRNA gene sequence comparisons, the isolate was identified as a member of the genus Frateuria and to be closely related to Frateuria terrea DSM 26515 T (98.2% similarity), Dyella thiooxydans ATSB10 T (98.2 %), Frateuria defendens HyOG T (97.9 %), Rhodanobacter glycinis MO64 T (97.8 %) and Frateuria aurantia DSM 6220 T (97.8 %). The novel strain MAH-13 T has a draft genome size of 3 682 848 bp (40 contigs), annotated with 3172 protein-coding genes, 49 tRNA genes and three rRNA genes. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain MAH-13 T and five closely related type strains were in the range of 73.7-85.5 % and 20.7-30.1%, respectively. The genomic DNA G+C content was determined to be 68.0 mol%. The predominant isoprenoid quinone was ubiquinone 8. The major fatty acids were identified as iso-C 15:0 , iso-C 16:0 and summed feature 9 (iso-C 17 : 1 ω 9 c and/or C 16:0 10-methyl). On the basis of dDDH and ANI values, genotypic analysis, and chemotaxonomic and physiological data, strain MAH-13 T represents a novel species within the genus Frateuria , for which the name Frateuria flava sp. nov. is proposed, with MAH-13 T (=KACC 19743 T =CGMCC 1.13655 T ) as the type strain.

A Gram-stain-negative, rod-shaped bacterial strain, designated SW123 T , was isolated from a deep-sea water sample collected from the Indian Ocean. Strain SW123 T was strictly aerobic, catalase- and oxidase-positive. The predominant cellular fatty acids were iso-C 15 : 0 , iso-C 17 : 0 and summed feature 9 (comprising C 16 : 0 -methyl or iso-C 17 : 1 ω 9 c ). Ubiquinone-8 was the sole respiratory quinone. The major polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. The genomic DNA G+C content was 49.4 mol%. 16S rRNA gene sequence analysis showed that strain SW123 T was closely related to Aliidiomarina shirensis AIS T (96.7 % sequence similarity), Aliidiomarina iranensis GBPy7 T (96.3%), Aliidiomarina haloalkalitolerans AK5 T (96.0%) and Aliidiomarina celeris F3105 T (95.9%). Phylogenetic trees based on 16S rRNA gene sequences showed that strain SW123 T represented a novel member of the genus Aliidiomarina , forming a distinct cluster with A. celeris F3105 T . On the basis of phylogenetic inference and phenotypic characteristics, we propose that strain SW123 T represents a novel species of the genus Aliidiomarina , with the name Aliidiomarina indica sp. nov. The type strain is SW123 T (=CGMCC1.16169 T =KCTC 82234 T ).

Whitefly, Bemisia tabaci (Gennadius) is an important pest of cotton causing direct damage as sap feeder and vector of Cotton leaf curl virus (CLCuV). Previous few studies suggest that female whiteflies are more efficient vector of begomovirusthan males, however the sex-biased transmission efficiency is still not clearly understood. Present studies with B. tabaci AsiaII-1 haplotype showed higher virus transmission efficiency of females compared to males. This variable begomovirus transmission efficiency has been related to previously identifiedkey factors associated with B. tabaci. The higher density of endosymbiont Arsenophonus and variable expression of some midgut proteins genes i.e. Cyclophilin, Knottin, Hsp40, Hsp70 may be possibly imparting higher vector competency to the females compared to males. The present studies suggest low abundance of Arsenophonus spp. as well as lower expressionof Cyclophilin genein males as compared to females. This is further supplemented by overexpression of Knottin, Hsp40, and Hsp70 genes in males compared to females and thus collectively all these factors might be playing a key role in low virus transmission efficiency of males. The relative density of Arsenophonus spp. and expression of midgut proteins genes in male and female whitefly first time enriches our understanding about sex-biased transmission efficiency of begomovirus., Competing Interests: The authors have declared that no competing interests exist.

A novel bacterial strain, designated IPMB12 T , isolated from the gut of the superworm Zophobas morio in Taiwan, was characterized using a polyphasic taxonomic approach. Cells were Gram-stain-negative, facultatively anaerobic, non-motile, coccoid or rod-shaped and formed translucent colonies. Optimal growth occurred at 25-37 °C, pH 9-10, and with 0-2 % NaCl. Phylogenetic analyses based on 16S rRNA gene sequences and coding sequences of 92 protein clusters indicated that strain IPMB12 T is affiliated with genus in the the family Orbaceae in the class Gammaproteobacteria . Strain IPMB12 T was most closely related to Gilliamella mensalis LMG 29880 T with a 94.6 % 16S rRNA gene sequence similarity. Strain IPMB12 T showed less than 71.6 % average nucleotide identity, less than 71.5 % average amino acid identity and less than 21.2 % digital DNA-DNA hybridization identity compared to the strains of related genera within the family Orbaceae . The major fatty acids of strain IPMB12 T were summed feature 8 (C18 : 1  ω 7 c and/or C18 : 1  ω 6 c ), C 16 : 0 and C 14 : 0 . The polar lipid profile consisted of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, one uncharacterized phosphoaminoglycolipid and one uncharacterized aminophospholipid. The major isoprenoid quinone was Q-8. Genomic DNA G+C content of strain IPMB12 T was 39.3 mol%. On the basis of phenotypic and genotypic properties and phylogenetic inference, strain IPMB12 T represents a novel species of a new genus in the family Orbaceae , for which the name Zophobihabitans entericus gen. nov., sp. nov. is proposed. The type strain is IPMB12 T (=BCRC 80908 T =LMG 32079 T =KCTC 82347 T =KACC 22323 T ).

A Gram-stain-negative, aerobic, rod-shaped strain (R2A-3 T ) was isolated from the toxin-producing dinoflagellate Centrodinium punctatum and identified as a novel genus and new species based on a polyphasic taxonomic approach. The optimum conditions for growth of the strain were at 25 °C, pH 8.0 and in the presence of 3 % (w/v) NaCl. Phylogenetic analyses based on 16S rRNA genes and 92 core genes sets revealed that strain R2A-3 T belongs to the family Nevskiaceae in the class Gammaproteobacteria and represented an independent taxon separated from other genera. The 16S rRNA gene of strain R2A-3 T showed the highest sequence similarity to Polycyclovorans algicola TG408 T (95.2%), Fontimonas thermophila HA-01 T (94.1%) and Sinimarinibacterium flocculans NH6-24 T (93.2%), and less than 92.8 % similarity to other genera in the family Nevskiaceae . The genome length of strain R2A-3 T was 3608892 bp with 65.2 mol% G+C content. Summed feature 8 (comprising C 18 : 1  ω 7 c and/or C 18 : 1  ω 6 c ) was the major fatty acid (>10 %). Diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine were detected as the major polar lipids. The major respiratory quinone was ubiquinone-8. According to its phylogenetic, phenotypic, chemotaxonomic and genomic features, strain R2A-3 T represents a new species in the new genus of the family Nevskiaceae . It is recommended to name it Flagellatimonas centrodinii gen. nov., sp. nov. The type strain is R2A-3 T (=KCTC 82469 T =GDMCC 1.2523 T ).

The genus Spartinivicinus , affiliated to the class Gammaproteobacteria , is an important marine member that produces prodiginines. Currently, its taxonomic assignment to family level is not well presented. Phylogeny of 16S rRNA gene sequences indicated that Spartinivicinus forms a monophyletic clade with Zooshikella , which is neighboured by Aestuariirhabdus of the family Aestuariirhabdaceae and another monophyletic clade of the family Endozoicomonadaceae . The 16S rRNA gene of Spartinivicinus ruber S2-4-1H T had sequence similarities to those of Aestuariirhabdus litorea GTF13 T , Zooshikella members and Endozoicomonas members of 93.4%, 93.2-93.4  and <92.5 %, respectively. Phylogenomic analysis based on 120 bacterial conserved single-copy genes highly supported placing Spartinivicinus as a sister member of Zooshikella , neighboured by Aestuariirhabdaceae and Endozoicomonadaceae members, indicating that Spartinivicinus and Zooshikella could be considered to belong to the same family. Thus, Zooshikellaceae fam. nov. is proposed to accommodate the two genera. Colonies of Spartinivicinus and Zooshikella are red-pigmented, which is different from Aestuariirhabdus (pale-yellow pigmented). The major respiratory quinone of S. ruber was ubiquinone (Q-9), similar to Zooshikella , but distinct from Aestuariirhabdus (Q-9 and Q-8). The predominant fatty acids and polar lipids of Spartinivicinus also showed a similar patterns to Zooshikella , but they were different from Aestuariirhabdus . Lastly, Spartinivicinus possessed a genome size of 6.68 Mbp and DNA G+C content of 40.1mol%, similar to Zooshikella , but much larger than Aestuariirhabdus . In addition, the 16S rRNA genes of Z. ganghwensis JC2044 T and Z. marina JC333 T possess sequence similarity of 99.79 %. Whole genome comparisons indicated that they shared 79.8 % digital DNA-DNA hybridization, 97.78 % average nucleotide identity and 97.31 % average amino acid identity values. Activities of catalase and oxidase for the two strains were positive. Hydrolysis of skimmed milk and Tweens (40, 60 and 80) was positive. Interestingly, the two strains produced different kinds of prodiginines. We propose that Z. marina is a later heterotypic synonym of Zooshikella ganghwensis .

Cells of bacterial strains G9 T and 7MK23 T , isolated from forest soil samples collected from the Dinghushan Biosphere Reserve, Guangdong Province, PR China, were Gram-stain-negative, aerobic and rod-shaped. Strain G9 T was motile with single polar flagellum and grew at 12-37 °C (optimum, 28 °C), pH 4.5-8.0 (optimum, pH 6.0-7.5) and in the presence of 0-3.5 % NaCl (optimum, 1.5%, w/v); while strain 7MK23 T was non-motile and grew at 12-42 °C (optimum, 28-33 °C), pH 2.5-8.5 (optimum, pH 4.5-6.5) and NaCl levels of 0-1.0 % (optimum, 0-0.5 %, w/v). Phylogenetic analysis based on 16S rRNA gene sequences revealed that both isolates fell within the cluster of the genus Dyella . The closely related species (with a 16S rRNA gene sequence similarity >98.65%) of strain G9 T were Dyella terrae JS14-6 T (99.0 %), D . kyungheensis THG-B117 T (98.8 %) and D . amyloliquefaciens DHC06 T (98.7 %) while that of strain 7MK23 T were D . mobilis DHON07 T (99.2 %) and D . flava DHOC52 T (99.1 %), but the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strains G9 T , 7MK23 T and the closely related Dyella species listed above were in the ranges of 77.5-83.8 % and 22.0-27.0 %, much lower than the species demarcation lines of 95.5 and 70 %, respectively. Phylogenomic analyses using UBCG and Phylophlan also supported that these two strains represent two novel species of Dyella . The major fatty acids of strain G9 T were iso-C 15 : 0 , iso-C 17 : 1  ω 9 c and iso-C 17 : 0 while that of strain 7MK23 T were iso-C 15 : 0 and anteiso-C 15 : 0 . Ubiquinone-8 was the only respiratory quinone detected in both strains. The polar lipids of strain G9 T consisted of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, and several unknown phospholipids, aminophospholipids, aminolipids and lipid while strain 7MK23 T contained phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylmethylethanolamine and several unknown phospholipids and aminophospholipids. The DNA G+C contents of strains G9 T and 7MK23 T were 64.7 and 63.4 mol%, respectively. On the basis of 16S rRNA gene sequence phylogenetic and phylogenomic analyses as well as phenotypic data obtained, we propose that strains G9 T and 7MK23 T represent two novel species of the genus Dyella , for which the names Dyella telluris sp. nov. (type strain G9 T =KACC 21725 T =GDMCC 1.2132 T ) and Dyella acidiphila sp. nov. (type strain 7MK23 T =KCTC 62739 T =GDMCC 1.1446 T ) are proposed.

Genome and proteome data predict the presence of both the reductive citric acid cycle (rCAC; also called the reductive tricarboxylic acid cycle) and the Calvin-Benson-Bassham cycle (CBB) in " Candidatus Endoriftia persephonae," the autotrophic sulfur-oxidizing bacterial endosymbiont from the giant hydrothermal vent tubeworm Riftia pachyptila. We tested whether these cycles were differentially induced by sulfide supply, since the synthesis of biosynthetic intermediates by the rCAC is less energetically expensive than that by the CBB. R. pachyptila was incubated under in situ conditions in high-pressure aquaria under low (28 to 40 μmol · h -1 ) or high (180 to 276 μmol · h -1 ) rates of sulfide supply. Symbiont-bearing trophosome samples excised from R. pachyptila maintained under the two conditions were capable of similar rates of CO 2 fixation. Activities of the rCAC enzyme ATP-dependent citrate lyase (ACL) and the CBB enzyme 1,3-bisphosphate carboxylase/oxygenase (RubisCO) did not differ between the two conditions, although transcript abundances for ATP-dependent citrate lyase were 4- to 5-fold higher under low-sulfide conditions. δ 13 C values of internal dissolved inorganic carbon (DIC) pools were varied and did not correlate with sulfide supply rate. In samples taken from freshly collected R. pachyptila , δ 13 C values of lipids fell between those collected for organisms using either the rCAC or the CBB exclusively. These observations are consistent with cooccurring activities of the rCAC and the CBB in this symbiosis. IMPORTANCE Previous to this study, the activities of the rCAC and CBB in R. pachyptila had largely been inferred from "omics" studies of R. pachyptila without direct assessment of in situ conditions prior to collection. In this study, R. pachyptila was maintained and monitored in high-pressure aquaria prior to measuring its CO 2 fixation parameters. Results suggest that ranges in sulfide concentrations similar to those experienced in situ do not exert a strong influence on the relative activities of the rCAC and the CBB. This observation highlights the importance of further study of this symbiosis and other organisms with multiple CO 2 -fixing pathways, which recent genomics and biochemical studies suggest are likely to be more prevalent than anticipated.

Taxonomic positions of four Gram-negative bacterial strains, which were isolated from larvae of two insects in Jeju, Republic of Korea, were determined by a polyphasic approach. Strains CWB-B4, CWB-B41 and CWB-B43 were recovered from larvae of Protaetia brevitarsis seulensis , whereas strain BWR-B9 T was from larvae of Allomyrina dichotoma . All the isolates grew at 10-37 °C, at pH 5.0-9.0 and in the presence of 4 % (w/v) NaCl. The 16S rRNA gene phylogeny showed that the four isolates formed two distinct sublines within the order Enterobacteriales and closely associated with members of the genus Jinshanibacter . The first group represented by strain CWB-B4 formed a tight cluster with Jinshanibacter xujianqingii CF-1111 T (99.3 % sequence similarity), whereas strain BWR-B9 T was most closely related to Jinshanibacter zhutongyuii CF-458 T (99.5 % sequence similarity). The 92 core gene analysis showed that the isolates belonged to the family Budviciaceae and supported the clustering shown in 16S rRNA gene phylogeny. The genomic DNA G+C content of the isolates was 45.2 mol%. A combination of overall genomic relatedness and phenotypic distinctness supported that three isolates from Protaetia brevitarsis seulensis are different strains of Jinshanibacter xujianqingii , whereas one isolate from Allomyrina dichotoma represents a new species of the genus Jinshanibacter . On the basis of results obtained here, Jinshanibacter allomyrinae sp. nov. (type strain BWR-B9 T =KACC 22153 T =NBRC 114879 T ) and Insectihabitans xujianqingii gen. nov., comb. nov. are proposed, with the emended descriptions of the genera Jinshanibacter , Limnobaculum and Pragia .

A Gram-stain-negative, rod-shaped and facultatively aerobic bacterial strain, designated F7430 T , was isolated from coastal sediment collected at Jingzi Wharf in Weihai, PR China. Cells of strain F7430 T were 0.3-0.4 µm wide, 2.0-2.6 µm long, non-flagellated, non-motile and formed pale-beige colonies. Growth was observed at 4-40 °C (optimum, 30 °C), pH 6.0-9.0 (optimum, pH 7.5-8.0) and at NaCl concentrations of 1.0-10.0 % (w/v; optimum, 1.0 %). The sole respiratory quinone of strain F7430 T was ubiquinone 8 and the predominant cellular fatty acids were summed feature 8 (C 18 : 1  ω 7 c / C 18 : 1  ω 6 c ; 60.7 %), summed feature 3 (C 16 : 1  ω 7 c /C 16 : 1  ω 6 c ; 30.2 %) and C 15 : 0 iso (13.9 %). The polar lipids of strain F7430 T consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, one unidentified phospholipid and three unidentified lipids. Results of 16S rRNA gene sequences analyses indicated that this strain belonged to the family Halieaceae and had high sequence similarities to Parahaliea aestuarii JCM 51547 T (95.3 %) and Halioglobus pacificus DSM 27932 T (95.2 %) followed by 92.9-95.0 % sequence similarities to other type species within the aforementioned family. The rpoB gene sequences analyses indicated that the novel strain had the highest sequence similarities to Parahaliea aestuarii JCM 51547 T (82.2 %) and Parahaliea mediterranea DSM 21924 T (82.2 %) followed by 75.2-80.5 % sequence similarities to other type species within this family. Phylogenetic analyses showed that strain F7430 T constituted a monophyletic branch clearly separated from the other genera of family Halieaceae . Whole-genome sequencing of strain F7430 T revealed a 3.3 Mbp genome size with a DNA G+C content of 52.6 mol%. The genome encoded diverse metabolic pathways including the Entner-Doudoroff pathway, assimilatory sulphate reduction and biosynthesis of dTDP-l-rhamnose. Based on results from the current polyphasic study, strain F7430 T is proposed to represent a novel species of a new genus within the family Halieaceae , for which the name Sediminihaliea albiluteola gen. nov., sp. nov. is proposed. The type strain of the type species is F7430 T (=KCTC 72873 T =MCCC 1H00420 T ).

A Gram-negative bacterium, designated S1-65 T , was isolated from soil samples collected from a cotton field located in the Xinjiang region of PR China. Results of 16S rRNA gene sequence analysis revealed that strain S1-65 T was affiliated to the genus Steroidobacter with its closest phylogenetic relatives being ' Steroidobacter cummioxidans ' 35Y (98.4 %), ' Steroidobacter agaridevorans ' SA29-B (98.3 %) and Steroidobacter agariperforans KA5-B T (98.3 %). 16S rRNA-directed phylogenetic analysis showed that strain S1-65 T formed a unique phylogenetic subclade next to ' S. agaridevorans ' SA29-B and S. agariperforans KA5-B T , suggesting that strain S1-65 T should be identified as a member of the genus Steroidobacter . Further, substantial differences between the genotypic properties of strain S1-65 T and the members of the genus Steroidobacter , including average nucleotide identity and digital DNA-DNA hybridization, resolved the taxonomic position of strain S1-65 T and suggested its positioning as representing a novel species of the genus Steroidobacter . The DNA G+C content of strain S1-65 T was 62.5 mol%, based on its draft genome sequence. The predominant respiratory quinone was ubiquinone-8. The main fatty acids were identified as summed feature 3 (C 16:1 ω6 c /C 16:1 ω7 c ), C 16 : 0 and iso-C 15 : 0 . In addition, its polar lipid profile was composed of aminophospholipid, diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. Here, we propose a novel species of the genus Steroidobacter : Steroidobacter gossypii sp. nov. with the type strain S1-65 T (=JCM 34287 T =CGMCC 1.18736 T ).

In this study, we report a Gram-stain-negative, rod-shaped, non-pigmented, motile and aerobic bacterium named strain MTZ26 T , which was isolated from deep-sea sediment sampled at a cold seep in the South China Sea. Growth of strain MTZ26 T occurred at 4-40 °C (optimum, 25-30 °C), pH 6.0-10.0 (optimum, 7.0-8.0) and with 1.0-11.0 % (w/v) NaCl (optimum, 6.0-8.0 %). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain MTZ26 T belonged to the genus Psychrosphaera and was closely related to Psychrosphaera aestuarii PSC101 T (97.5 % sequence similarity) and Psychrosphaera haliotis KDW4 T (97.5 %). Genomic analysis indicated that strain MTZ26 T contains a circular chromosome of 3 331 814 bp with G+C content of 42.2 mol%. The predominant respiratory quinone of MTZ26 T was ubiquinone-8. The polar lipids of MTZ26 T contained phosphatidylglycerol, phosphatidylethanolamine, one unidentified aminophospholipid and one unidentified phospholipid. The major fatty acids of strain MTZ26 T contained C 15:0, C 16:0, C 17:0 , C 17 : 1  ω8 c , C 10 : 0 3-OH, C 11 : 0 3-OH, C 15 : 1  ω8 c and summed feature 8 (C 18 : 1  ω7 c or/and C 18 : 1  ω6 c ). Results of phylogenetic, physiological, biochemical and morphological analyses suggested that strain MTZ26 T represents a novel species of the genus Psychrosphaera , and the name Psychrosphaera ytuae sp. nov. is proposed with the type strain MTZ26 T (=MCCC 1K05568 T =JCM 34321 T ).

In the ocean, most hosts acquire their symbionts from the environment. Due to the immense spatial scales involved, our understanding of the biogeography of hosts and symbionts in marine systems is patchy, although this knowledge is essential for understanding fundamental aspects of symbiosis such as host-symbiont specificity and evolution. Lucinidae is the most species-rich and widely distributed family of marine bivalves hosting autotrophic bacterial endosymbionts. Previous molecular surveys identified location-specific symbiont types that "promiscuously" form associations with multiple divergent cooccurring host species. This flexibility of host-microbe pairings is thought to underpin their global success, as it allows hosts to form associations with locally adapted symbionts. We used metagenomics to investigate the biodiversity, functional variability, and genetic exchange among the endosymbionts of 12 lucinid host species from across the globe. We report a cosmopolitan symbiont species, Candidatus Thiodiazotropha taylori, associated with multiple lucinid host species. Ca. T. taylori has achieved more success at dispersal and establishing symbioses with lucinids than any other symbiont described thus far. This discovery challenges our understanding of symbiont dispersal and location-specific colonization and suggests both symbiont and host flexibility underpin the ecological and evolutionary success of the lucinid symbiosis., Competing Interests: The authors declare no competing interest., (Copyright © 2021 the Author(s). Published by PNAS.)

The rapid detection of extended-spectrum β-lactamase Enterobacterales (ESBL-E) in a positive blood culture is important in order to initiate an appropriate antibiotic therapy and thus decrease mortality. We evaluated the new BL-RED (β-Lactamase Rapid Electrochemical Detection) test in 100 positive blood culture broths to detect (in ten minutes) the presence or absence of ESBL-E. The BL-RED test appears to be an easy, rapid and reliable test to detect the presence of ESBL directly in Gram negative bacilli-positive blood culture broths, with good performances (sensibility =97.3%, specificity =90.5%, predictive positive value =85.7% and predictive negative value =98.3%). This test could be useful for therapeutic decisions and adjustments of sepsis empirical antibiotic therapy, particularly in wards where the ecology is unfavorable, such as in intensive care units.

A novel Gram-stain-negative, short rod-shaped, facultatively anaerobic, non-motile, non-gliding, oxidase-positive and catalase-negative bacterium, designated ML27 T , was isolated from oyster homogenate in Rushan, Weihai, PR China. Growth occurred at 20-33 °C (optimum, 30 °C), at pH 7.0-9.0 (optimum, pH 7.5-8.0) and in the presence of 1-6 % (w/v) NaCl (optimum, 3 %). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain ML27 T was 90.7 % similar to Suttonella ornithocola DSM 18249 T , 89.2 % to Suttonella indologenes JCM 1478 T and 88.2 % to Cardiobacterium hominis DSM 8339 T ; similarities to other species were less than 90 %. The average amino acid identity between strain ML27 T , S. indologenes JCM 1478 T , S. ornithocola DSM 18249 T , C. hominis DSM 8339 T and Dichelobacter nodosus ATCC 25549 T were 46.23, 45.86, 45.54 and 45.84 %, respectively. Phylogenomic tree and phylogenetic analyses based on 16S rRNA gene sequences showed that the isolate formed a novel family-level clade in the order Cardiobacteriales . The sole respiratory quinone was ubiquinone-7 (Q-7). The dominant cellular fatty acids were summed feature 8 (C 18 : 1  ω7 c /C 18 : 1  ω6 c ; 46.3 %), C 16 : 0 (17.8 %) and summed feature 3 (C 16 : 1  ω7 c /C 16 : 1  ω6 c ; 13.5 %). The DNA G+C content of strain ML27 T was 45.6 mol%. Polar lipids included phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and one unidentified lipid. Comparative analyses of 16S rRNA gene sequences, genomic distinctiveness and characterization indicated that strain ML27 T represents a novel species of a new genus within a novel family of the order Cardiobacteriales , for which the name Ostreibacterium oceani gen. nov., sp. nov. is proposed. The type strain of Ostreibacterium oceani is ML27 T (=MCCC 1H00372 T =KCTC 72155 T ). In addition, a novel family, Ostreibacteriaceae fam. nov., is proposed to accommodate the genus Ostreibacterium .

Most animals cannot digest cellulose but have symbiotic microbes that degrade the matrix polysaccharides of plant matter. Herbivorous and omnivorous marine fish are similarly expected to rely on symbiotic microbes, but reports to date on cellulase-producing bacteria in fish intestines are limited. Here, we report the isolation of new cellulase-producing bacteria from the marine omnivorous teleost, blackfish (Girella melanichthys), and the characterization of cellulase activity. Three strains of cellulase-producing bacteria sp. were isolated from the hindgut of wild G. melanichthys. The strains of cellulase-producing bacteria grew in medium with artificial seawater but not in NaCl alone. Growth was optimum at 20-35°C, but there was no growth at 40°C, suggesting adaptation in a marine environment at a low temperature. Isolates were identified to Microbulbifer sp., among which GL-2 strain produced a high enzyme activity. The GL-2 strain was further used for enzyme characterization with carboxymethyl cellulose (CMC) as the substrate. Maximum activity of the cellulase was observed at 60°C, and activity was more than 30% at 20°C, while commercial cellulase Enthiron showed an optimum activity at 50°C and 17% activity at 20°C. Hydrolytic products by GL-2 cellulase were cellobiose but not glucose, suggesting a deficiency of β-glucosidase activity. Active gel electrophoresis containing CMC showed five bands, suggesting several cellulolytic enzymes. The GL-2 strain and its enzyme are potential probiotics for aquaculture fish and the industrial production of cellobiose.

Bacterial urinary tract infection (UTI) is a common condition affecting dogs. Urine culture and antimicrobial susceptibility test, associated with the identification of underlying cause, are of primary importance in order to select a correct treatment, especially in presence of comorbidities. Two cases of immunecompromised dogs affected by urinary tract infection (UTI) have been described: the first, probably immunosuppressed due to old age, was in poor body condition, with severe odontolithiasis and periodontitis; the second was affected by chronic kidney disease in advanced stage. Urine cultures isolated two rare and atypical pathogens, Moellerella wisconsensis and Brevundimonas vesicularis, both showing sensitivity versus floroquinolones which were selected for the treatment. After a 4 weeks treatment, a second culture demonstrated the resolution of infection in both cases, in absence of clinical signs.To date neither of the two bacteria have been reported as cause of UTI in dog.

Bacteremia induced by wound myiasis is uncommon and therefore rarely suspected by clinicians when treating patients with neglected wounds. We present a case of Ignatzschineria larvae bacteremia as a complication of Lucilia sp. maggot wound myiasis in a young male migrant. This is the first reported human case of Ignatzschineria bacteremia in Slovenia and one of the 2 described in the literature where the fly larvae infesting the wounds of the patient with Ignatzschineria bacteremia were not only suspected to be Lucilia sp. but also entomologically identified.

Some pathogenic microbes can be used for nefarious applications and instigate population-based fear. In a bio-threat scenario, rapid and accurate methods to detect biological agents in a wide range of complex environmental and clinical matrices, is of paramount importance for the implementation of mitigation protocols and medical countermeasures. This study describes targeted and shot-gun tandem MS based approaches for the verification of biological agents from the environmental samples. The marker proteins and peptides were elucidated by an exhaustive literature mining, in silico analysis of prioritized proteins, and MS/MS analysis of abundant proteins from selected bacterial species. For the shot-gun methodology, tandem MS analysis of abundant peptides was carried from spiked samples. The validation experiments employing a combination of shot-gun tandem MS analysis and a targeted search reported here is a proof of concept to show the applicability of the methodology for the unambiguous verification of biological agents at sub-species level, even with limited fractionation of crude protein extracts from environmental samples.

We investigated the dynamics of the bacterial composition and metabolic function within Akashiwo sanguinea bloom using a 100-L indoor microcosm and metagenomic next-generation sequencing. We found that the bacterial community was classified into three groups at 54% similarity. Group I was associated with "during the A. sanguinea bloom stage" and mainly consisted of Alphaproteobacteria, Flavobacteriia and Gammaproteobacteria. Meanwhile, groups II and III were associated with the "late bloom/decline stage to post-bloom stage" with decreased Flavobacteriia and Gammaproteobacteria in these stages. Upon the termination of the A. sanguinea bloom, the concentrations of inorganic nutrients (particularly PO 4 3- , NH 4 + and dissolved organic carbon) increased rapidly and then decreased. From the network analysis, we found that the A. sanguinea node is associated with certain bacteria. After the bloom, the specific increases in NH 4 + and PO 4 3- nodes are associated with other bacterial taxa. The changes in the functional groups of the bacterial community from chemoheterotrophy to nitrogen association metabolisms were consistent with the environmental impacts during and after A. sanguinea bloom. Consequently, certain bacterial communities and the environments dynamically changed during and after harmful algal blooms and a rapid turnover within the bacterial community and their function can respond to ecological interactions.

Four novel strains isolated from the cloacal contents of snow finches ( Montifringilla taczanowskii ) were characterized as aerobic, Gram-stain-negative, slightly motile, and rod-shaped. Analysis of the 16S rRNA gene sequence revealed that strain CF-458 T had the highest similarities of 96.9 and 96.4 % with Limnobaculum parvum HYN0051 T and Pragia fontium DSM 5563 T , while strain CF-1111 T shared the highest similarities of 96.4 and 96.1 % with Pantoea rodasii LMG 26273 T and Pectobacterium punjabense SS95 T . Phylogenomic analysis showed the four isolates were separated into group Ⅰ (CF-458 T and CF-917) and group Ⅱ (CF-1111 T and CF-509), and clustered independently in the vicinity of the genera Limnobaculum and Pragia . Summed feature 3 (C 16 : 1  ω 7 c and/or C 16 : 1  ω 6 c , 23.9 and 17.2 %, respectively), C 16 : 0 (21.8 and 22.1 %, respectively) and C 14 : 0 (10.6 and 17.7 %, respectively) were the common major fatty acids, and summed feature 8 (C 18 : 1  ω 7 c and/or C 18 : 1  ω 6 c , 12.3 %) was also a major fatty acid for strain CF-458 T while cyclo-C 17 : 0 (13.1%) was for strain CF-1111 T . Both had Q-8 as the sole quinone and contained phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol as the major polar lipids. The DNA G+C content of strains CF-458 T and CF-1111 T was 45.7 and 45.4 mol%, respectively. Based on taxonomic position in the phylogenomic tree and phenotypic properties, two novel species of a new genus within the family Budviciaceae are thus proposed, with the name Jinshanibacter gen. nov., zhutongyuii sp. nov. (type strain CF-458 T =CGMCC 1.16483 T =GDMCC 1.1586 T =JCM 33489 T ) and Jinshanibacter xujianqingii sp. nov. (type strain CF-1111 T =CGMCC 1.16786 T =GDMCC 1.1587 T =JCM 33490 T ), respectively.

A Gram-stain-negative, motile, facultatively anaerobic rod-shaped bacterium with a polar flagellum, designated strain S7 T was isolated from seawater sample collected at Uljin marina, in the East Sea of the Republic of Korea. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that strain S7 T was affiliated with members of genus Ferrimonas, showing the highest sequence similarities to the type strains Ferrimonas senticii P2S11 T (95.7 %), Ferrimonas balearica PAT T (95.7 %) and Ferrimonas pelagia CBA4601 T (95.1 %). The genome was 4.13 Mbp with a DNA G+C content of 49.4 %. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) between S7 T and F. senticii P2S11 T and F. balearica PAT T yielded ANI values of 71.9 and 70.7 %, and dDDH values of 15.1 and 13.9 %, respectively. The genome of S7 T was predicted to encode triacylglycerol lipase, phospholipase A1/A2 and lysophospholipase as well as esterase involved in lipolytic processes. Growth was observed at 8-31 °C (optimum 27 °C), at pH 7-9 (optimum pH 7), and with 1-6 % NaCl (optimum 2 %). The respiratory quinones were MK-7 and Q-7 and the major fatty acids (>10 %) were C 16 : 0 , C 16 : 1 ω9 c , C 17 : 1 ω8 c , and summed feature 3 (C 16 : 1 ω7 c and/or C 16 : 1 ω6 c ). The major polar lipids were identified as phosphatidylethanolamine, phosphatidylglycerol, two unidentified phospholipids, and three unidentified lipids. On the basis of the results of this polyphasic analysis, it was determined that the strain represents a novel species of the genus Ferrimonas , for which the name Ferrimonas lipolytica sp. nov. is proposed. The type strain is S7 T (=KCTC 72490 T =JCM 33793 T ).

Here, we describe three endosymbiotic bacterial strains isolated from the gills of the shipworm, Bankia setacea (Teredinidae: Bivalvia). These strains, designated as Bs08 T , Bs12 T and Bsc2 T , are Gram-stain-negative, microaerobic, gammaproteobacteria that grow on cellulose and a variety of substrates derived from lignocellulose. Phenotypic characterization, phylogeny based on 16S rRNA gene and whole genome sequence data, amino acid identity and percentage of conserved proteins analyses, show that these strains are novel and may be assigned to the genus Teredinibacter . The three strains may be differentiated and distinguished from other previously described Teredinibacter species based on a combination of four characteristics: colony colour (Bs12 T , purple; others beige to brown), marine salt requirement (Bs12 T , Bsc2 T and Teredinibacter turnerae strains), the capacity for nitrogen fixation (Bs08 T and T. turnerae strains) and the ability to respire nitrate (Bs08 T ). Based on these findings, we propose the names Teredinibacter haidensis sp. nov. (type strain Bs08 T =ATCC TSD-121 T =KCTC 62964 T ), Teredinibacter purpureus sp. nov. (type strain Bs12 T =ATCC TSD-122 T =KCTC 62965 T ) and Teredinibacter franksiae sp. nov. (type strain Bsc2 T =ATCC TSD-123 T =KCTC 62966 T ).

Strain M2 T , isolated from marine sediment collected at Jeju Island, was an aerobic, Gram-stain-negative, oxidase- and catalase-positive, motile, rod-shaped bacterium that formed circular, raised, yellow colonies. Strain M2 T grew at 15-42 °C, pH 5.5-9.0 and with 1-9 % (w/v) NaCl. Phylogenetic analysis based on its 16S rRNA gene sequences indicated that strain M2 T was closely related to Kineobactrum sediminis F02 T (98.0 % sequence similarity). Ubiquinone-8 was determined to be the sole respiratory quinone. Summed feature 3 (C 16 : 1  ω 6 c /C 16 : 1  ω 7 c ) and summed feature 8 (C 18 : 1  ω 7 c /C 18 : 1  ω 6 c ) were identified as the predominant fatty acids. The DNA G+C content and digital DNA-DNA relatedness between strain M2 T and K. sediminis F02 T were 60.7 mol% and 19.5 %, respectively. Phosphatidylglycerol and phosphatidylethanolamine were identified as the major polar lipids. Thus, polyphasic characterization revealed that strain M2 T represents a novel species in the genus Kineobactrum , for which the name Kineobactrum salinum sp. nov. is proposed. The type strain is M2 T (=KCTC 72815 T =VTCC 910108 T ).

A taxonomic study was carried out on strain C16B3 T , which was isolated from deep seawater of the Pacific Ocean. The bacterium was Gram-stain-negative, oxidase- and catalase- positive and rod-shaped. Growth was observed at salinities of 0-8.0 % and at temperatures of 10-45 °C. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain C16B3 T belonged to the genus Solimonas , with the highest sequence similarity to Solimonas terrae KIS83-12 T (97.2 %), followed by Solimonas variicoloris MN28 T (97.0 %) and the other four species of the genus Solimonas (94.5 -96.8 %). The average nucleotide identity and estimated DNA-DNA hybridization values between strain C16B3 T and the type strains of the genus Solimonas were 74.05-79.48 % and 19.5-22.5 %, respectively. The principal fatty acids (>5 %) were summed feature 8 (C 18 : 1  ω 7 c /C 18 : 1  ω 6 c ; 20.9 %), iso-C 16 : 0 (14.6 %), C 16 : 1  ω 5 c (9.4 %), iso-C 12 : 0 (8.4 %), summed feature 2 (C 14 : 0 3-OH/iso I-C 16 : 1 and C 12 : 0 aldehyde; 6.8 %) and C 16 : 0 (5.5 %). The G+C content of the chromosomal DNA was 65.37 mol%. The respiratory quinone was determined to be Q-8 (100 %). The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, four unidentified aminolipids, six unidentified phospholipids and one unidentified polar lipid. The combined genotypic and phenotypic data show that strain C16B3 T represents a novel species within the genus Solimonas , for which the name Solimonas marina sp. nov. is proposed, with the type strain C16B3 T (=MCCC 1A04678 T =KCTC 52314 T ).

The environment of plant rhizosphere soil differs from that of non-rhizosphere soil due to the secretion of mucilage polysaccharides from the roots. This environment is regarded as one of the preferential habitats for agar-degrading bacteria. In a previous study, agar-degrading Steroidobacter agariperforans KA5-B T was isolated from agar-enriched agricultural soil using diffusible metabolites from Rhizobiales bacteria. Based on the hypothesis that similar characteristic bacteria still exist in the rhizosphere, isolation was performed using rhizosphere soils. Agar-degrading SA29-B T and YU21-B were isolated from onion and soybean rhizosphere soils. The 16S rRNA genes of these strains showed ≥98.7% identities with the most closely related strain KA5-B T . However, differences were noted in polysaccharide utilization, and average nucleotide identities were <95-96% against strain KA5-B T , indicating that they are different species from S. agariperforans KA5-B T . To investigate the distribution of bacterial sequences affiliated with novel strains, a primer set was designed and a meta-analysis of the 16S rRNA gene was performed. Sequences were widely distributed in rhizospheres throughout Japan, but varied in plant- and region-dependent manners. Regarding phenotypic characterization, distinguishable features were observed in growth temperatures, pH, and dominant fatty acids. SA29-B T and YU21-B grew at 15-40°C and pH 6.0-12 and contained C 16:0 as the dominant cell fatty acid, whereas KA5-B T showed no growth at 40°C and pH 12 and contained a moderate amount of C 16:0 . Based on these characteristics, SA29-B T (JCM 333368 T =KCTC 72223 T ) and YU21-B (JCM 333367=KCTC 72222) represent novel species in the genus Steroidobacter, for which the name Steroidobacter agaridevorans sp. nov. is proposed.

The elevated NH 3 -N and NO 2 -N pollution problems in mariculture have raised concerns because they pose threats to animal health and coastal and offshore environments. Supplement of Marichromatium gracile YL28 (YL28) into polluted shrimp rearing water and sediment significantly decreased ammonia and nitrite concentrations, showing that YL28 functioned as a novel safe marine probiotic in the shrimp culture industry. The diversity of aquatic bacteria in the shrimp mariculture ecosystems was studied by sequencing the V4 region of 16S rRNA genes, with respect to additions of YL28 at the low and high concentrations. It was revealed by 16S rRNA sequencing analysis that Proteobacteria, Planctomycete and Bacteroidetes dominated the community (>80% of operational taxonomic units (OTUs)). Up to 41.6% of the predominant bacterial members were placed in the classes Gammaproteobacteria (14%), Deltaproteobacteria (14%), Planctomycetacia (8%) and Alphaproteobacteria (5.6%) while 40% of OTUs belonged to unclassified ones or others, indicating that the considerable bacterial populations were novel in our shrimp mariculture. Bacterial communities were similar between YL28 supplements and control groups (without addition of YL28) revealed by the β-diversity using PCoA, demonstrating that the additions of YL28 did not disturb the microbiota in shrimp mariculture ecosystems. Instead, the addition of YL28 increased the relative abundance of ammonia-oxidizing and denitrifying bacteria. The quantitative PCR analysis further showed that key genes including nifH and amoA involved in nitrification and nitrate or nitrite reduction significantly increased with YL28 supplementation ( p < 0.05). The supplement of YL28 decreased the relative abundance of potential pathogen Vibrio . Together, our studies showed that supplement of YL28 improved the water quality by increasing the relative abundance of ammonia-oxidizing and denitrifying bacteria while the microbial community structure persisted in shrimp mariculture ecosystems.

Aquaculture releases organic matter to the water column through excretion, fecal pellets, and uneaten food, but also by the continuous release of fish epithelium mucus. The effect of the latter on natural bacterial assemblages was determined using ammonium amended experiments at Puyuhuapi fjord in Chilean Patagonia. Mucus was added to seawater coming from 2 and 100 m depth and ammonium, nitrite and nitrate, dissolved organic carbon (DOC), picoplankton abundance, and active composition (i-tag 16S rRNA) were followed for 24 h. The results showed a significant response from the microbial community but only at surface depth after 2 and 6 h of incubation. A reduction of DOC and ammonium concentration and accumulation of nitrite and nitrate over time was observed, mainly at 100 m. Changes in the composition of active bacteria between treatments were observed at different taxonomic levels, associated with Alphaproteobacteria (Clade SAR11), Bacteroidetes (Polaribacter) and Gammaproteobacteria (Colwellia, Oceaniserpentilla) and other bacteria such as Nitrospina sp, a nitrite-oxidizing bacteria at some hours during the incubation. Fish pathogens, such as Vibrio and Piscirickettsia were rare (<0.02%). Overall, our study suggests that fish mucus can cause rapid modifications in microbial assemblages and stimulate organic matter and nutrient cycling, including heterotrophic and autotrophic (nitrification) in areas influenced by aquaculture., (© 2020 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.)

A Gram-negative, filamentous aerobic bacterium designated as strain Mgbs1 T was isolated on 12 April 2017 from the subsurface soil and leaf litter substrate at the base of a Koompassia malaccensis tree in a tropical peat swamp forest in the northern regions of the state of Selangor, Malaysia (3° 39' 04.7' N 101° 17' 43.7'' E). Phylogenetic analyses based on the full 16S rRNA sequence revealed that strain Mgbs1 T belongs to the genus Chitinophaga with the greatest sequence similarity to Chitinophaga terrae KP01 T (97.65 %), Chitinophaga jiangningensis DSM27406 T (97.58 %), and Chitinophaga dinghuensis DHOC24 T (97.17 %). The major fatty acids of strain Mgbs1 T (>10 %) are iso-C 15 : 0 , C 16 : 1  ω 5 c and iso-C 17 : 0 3-OH while the predominant respiratory quinone is menaquinone-7. Strain Mgbs1 T has a complete genome size of 8.03 Mb, with a G+C content of 48.5 mol%. The DNA-DNA hybridization (DDH) score between strain Mgbs1 T and C. jiangningensis DSM27406 T was 15.9 %, while in silico DDH values of strain Mgbs1 T against C. dinghuensis DHOC24 T and C. terrae KP01 T were 20.0 and 19.10% respectively. Concurrently, Average Nucleotide Identity (ANI) scores between strain Mgbs1 T against all three reference strains are 73.2 %. Based on the phenotypic, chemotaxonomic, and phylogenetic consensus, strain Mgbs1 T represents a novel species of the genus Chitinophaga , for which the name Chitinophaga extrema sp. nov. is proposed (=DSM 108835 T =JCM 33276 T ).

Alginate lyases play important roles in alginate degradation in the ocean. Although a large number of alginate lyases have been characterized, little is yet known about those in extremely cold polar environments, which may have unique mechanisms for environmental adaptation and for alginate degradation. Here, we report the characterization of a novel PL7 alginate lyase AlyC3 from Psychromonas sp. C-3 isolated from the Arctic brown alga Laminaria , including its phylogenetic classification, catalytic properties, and structure. We propose the establishment of a new PM-specific subfamily of PL7 (subfamily 6) represented by AlyC3 based on phylogenetic analysis and enzymatic properties. Structural and biochemical analyses showed that AlyC3 is a dimer, representing the first dimeric endo-alginate lyase structure. AlyC3 is activated by NaCl and adopts a novel salt-activated mechanism; that is, salinity adjusts the enzymatic activity by affecting its aggregation states. We further solved the structure of an inactive mutant H127A/Y244A in complex with a dimannuronate molecule and proposed the catalytic process of AlyC3 based on structural and biochemical analyses. We show that Arg 82 and Tyr 190 at the two ends of the catalytic canyon help the positioning of the repeated units of the substrate and that His 127 , Tyr 244 , Arg 78 , and Gln 125 mediate the catalytic reaction. Our study uncovers, for the first time, the amino acid residues for alginate positioning in an alginate lyase and demonstrates that such residues involved in alginate positioning are conserved in other alginate lyases. This study provides a better understanding of the mechanisms of alginate degradation by alginate lyases., Competing Interests: Conflict of interest—The authors declare that they have no conflicts of interest with the contents of this article., (© 2020 Xu et al.)

A novel Gram-stain-negative, non-endospore-forming, motile, and aerobic bacterial strain, M105 T , was isolated from coral Porites lutea , and was subjected to a polyphasic taxonomic study. Global alignment based on 16S rRNA gene sequences indicated that M105 T shares the highest sequence identity of 94.5 % with Aliikangiella marina GYP-15 T . The average nucleotide identity (ANI) and average amino acid identity (AAI) between M105 T and A. marina GYP-15 T was 69.8 and 71.6 %, respectively. On the basis of the results of phenotypic, chemotaxonomic, phylogenetic, phylogenomic, and comparative genomic analyses, it is concluded that M105 T should represent a novel species in the genus Aliikangiella , for which the name Aliikangiella coralliicola sp. nov. is proposed. The type strain is M105 T (=MCCC 1K03773 T = KCTC 72442 T ). Furthermore, the family Kangiellaceae was classified into two families on the basis of phylogenetic, phylogenomic, polar lipid profile and motility variations. The novel family Pleioneaceae fam. nov. is proposed to accommodate the genera Aliikangiella and Pleionea .

Transferring antimicrobial-resistant bacteria from companion animals to human hosts has become increasingly common. Data regarding antimicrobial susceptibility could help veterinarians to select the most appropriate antibiotic treatment. However, standardized and ongoing surveys regarding antimicrobial resistance remain limited. In this study, we investigated the antimicrobial-susceptibility patterns and trends of bacteria isolated from stray dogs, hospital-admitted dogs, and veterinary staff in South Korea from 2018 to 2019. The minimum inhibitory concentrations of different antimicrobials for Staphylococcus spp., Enterobacterales, and Enterococcus spp. were determined to establish representatives of different antibiotic classes relevant for treatment or surveillance. For coagulase-positive and -negative Staphylococci, resistance to gentamicin was <27 %, while that to ampicillin and penicillin was high (33-80 %). The mecA-detection rates among staphylococcal isolates were 28.5 %, 42.6 %, and 32 % from stray dogs, hospital-admitted dogs, and veterinary staffs, respectively. For Enterobacterales, resistance to carbapenems was low (0-6%). A total of 31.2 % and 18.9 % of Enterobacterales isolates from stray dogs and hospital-admitted dogs were confirmed to possess at least one of bla CTX-M , bla SHV , or bla TEM . Additionally, Enterococcus spp. isolates showed no resistance to vancomycin. These results demonstrate that dogs are commonly colonized with antimicrobial-resistant bacteria and highlight the need for further investigation., (Copyright © 2020 Elsevier B.V. All rights reserved.)