Paenibacillus glacialis sp. nov., isolated from the Kafni glacier of the Himalayas, India

Prevalence and abundance of antibiotic-resistant genes in culturable bacteria inhabiting a non-polar passu glacier, karakorum mountains range, Pakistan

Natural pristine environments including cold habitats are thought to be the potent reservoirs of antibiotic-resistant genes and have been recurrently reported in polar glaciers' native bacteria, nevertheless, their abundance among the non-polar glaciers' inhabitant bacteria is mostly uncharted. Herein we evaluated antibiotic resistance profile, abundance of antibiotic-resistant genes plus class 1, 2, and 3 integron integrases in 65 culturable bacterial isolates retrieved from a non-polar glacier. The 16S rRNA gene sequencing analysis identified predominantly Gram-negative 43 (66.15%) and Gram-positive 22 (33.84%) isolates. Among the Gram-negative bacteria, Gammaproteobacteria were dominant (62.79%), followed by Betaproteobacteria (18.60%) and Alphaproteobacteria (9.30%), whereas Phyla Actinobacteria (50%) and Firmicutes (40.90%) were predominant among Gram-positive. The Kirby Bauer disc diffusion method evaluated significant antibiotic resistance among the isolates. PCR amplification revealed phylum Proteobacteria predominantly carrying 21 disparate antibiotic-resistant genes like; _blaAmpC 6 (100%), _blaVIM-1, _blaSHV and _blaDHA 5 (100%) each, _blaOXA-1 1 (100%), _blaCMY-4 4 (100%), followed by Actinobacteria 14, Firmicutes 13 and Bacteroidetes 11. Tested isolates were negative for _blaKPC, qnrA, vanA, ermA, ermB, intl2, and intl3. Predominant Gram-negative isolates had higher MAR index values, compared to Gram-positive. Alignment of protein homology sequences of antibiotic-resistant genes with references revealed amino acid variations in _blaNDM-1, _blaOXA-1, _blaSHV, mecA, aac(6)-Ib3, tetA, tetB, sul2, qnrB, gyrA, and intI1. Promising antibiotic-resistant bacteria, harbored with numerous antibiotic-resistant genes and class 1 integron integrase with some amino acid variations detected, accentuating the mandatory focus to evaluate the intricate transcriptome analysis of glaciated bacteria conferring antibiotic resistance.

Secretome of Paenibacillus sp. S-12 provides an insight about its survival and possible pathogenicity

Our aim in this study was to characterize and investigate the secretome of Paenibacillus sp. S-12 by nanoLC-MS/MS tool-based analysis of trypsin digested culture supernatant proteins. Using a bioinformatics and combined approach of mass spectrometry, we identified 657 proteins in the secretome. Bioinformatic tools such as PREDLIPO, SecretomeP 2.0, SignalP 4.1, and PSORTb were used for the subcellular localization and categorization of secretome on basis of signal peptides. Among the identified proteins, more than 25% of the secretome proteins were associated with virulence proteins including flagellar, adherence, and immune modulators. Gene ontology analysis using Blast2GO tools categorized 60 proteins of the secretome into biological processes, cellular components, and molecular functions. KEGG pathway analysis identified the enzymes or proteins involved in various biosynthesis and degradation pathways. Functional analysis of secretomes reveals a large number of proteins involved in the uptake and exchange of nutrients, colonization, and chemotaxis. A good number of proteins were involved in survival and defense mechanism against oxidative stress, the production of toxins and antimicrobial compounds. The present study is the first report of the in-depth protein profiling of Paenibacillus bacterium. In summary, the current findings of Paenibacillus sp. S-12 secretome provide basic information to understand its survival and the possible pathogenic mechanism.

Antimicrobial properties of the novel bacterial isolate Paenibacilllus sp. SMB1 from a halo-alkaline lake in India

Antibiotic-resistance is ever growing burden on our society for the past many years. Many synthetic chemistry approaches and rational drug-design have been unable to pace up and tackle this problem. Natural resources, more specifically, the microbial diversity, on the other hand, make a traditional and still the best platform to search for new chemical scaffolds and compounds. Here, we report the antimicrobial characteristics of novel bacterial isolate from a salt lake in India. We screened the bacterial isolates for their inhibitory activity against indicator bacteria and found that four novel species were able to prevent the growth of test strains studied in vitro. Further, we characterized one novel species (SMB1^T = SL4-2) using polyphasic taxonomic approaches and also purified the active ingredient from this bacterium. We successfully characterized the antimicrobial compound using mass spectroscopy and amino acid analysis. We also allocated two novel biosynthetic gene clusters for putative bacteriocins and one novel non-ribosomal peptide gene cluster in its whole genome. We concluded that the strain SMB1^T belonged to the genus Paenibacilllus with the pairwise sequence similarity of 98.67% with Paenibacillus tarimensis DSM 19409^T and we proposed the name Paenibacillus sambharensis sp. nov. The type strain is SMB1^T (=MTCC 12884 = KCTC 33895^T).

The Structural Basis for a Transition State That Regulates Pore Formation in a Bacterial Toxin

The cholesterol-dependent cytolysin (CDC) genes are present in bacterial species that span terrestrial, vertebrate, and invertebrate niches, which suggests that they have evolved to function under widely different environmental conditions. Using a combination of biophysical and crystallographic approaches, we reveal that the relative stability of an intramolecular interface in the archetype CDC perfringolysin O (PFO) plays a central role in regulating its pore-forming properties. The disruption of this interface allows the formation of the membrane spanning β-barrel pore in all CDCs. We show here that the relative strength of the stabilizing forces at this interface directly impacts the energy barrier posed by the transition state for pore formation, as reflected in the Arrhenius activation energy (E_a) for pore formation. This change directly impacts the kinetics and temperature dependence of pore formation. We further show that the interface structure in a CDC from a terrestrial species enables it to function efficiently across a wide range of temperatures by minimizing changes in the strength of the transition state barrier to pore formation. These studies establish a paradigm that CDCs, and possibly other β-barrel pore-forming proteins/toxins, can evolve significantly different pore-forming properties by altering the stability of this transitional interface, which impacts the kinetic parameters and temperature dependence of pore formation.IMPORTANCE The cholesterol-dependent cytolysins (CDCs) are the archetype for the superfamily of oligomeric pore-forming proteins that includes the membrane attack complex/perforin (MACPF) family of immune defense proteins and the stonefish venom toxins (SNTX). The CDC/MACPF/SNTX family exhibits a common protein fold, which forms a membrane-spanning β-barrel pore. We show that changing the relative stability of an extensive intramolecular interface within this fold, which is necessarily disrupted to form the large β-barrel pore, dramatically alters the kinetic and temperature-dependent properties of CDC pore formation. These studies show that the CDCs and other members of the CDC/MACPF/SNTX superfamily have the capacity to significantly alter their pore-forming properties to function under widely different environmental conditions encountered by these species.

Identification and characterization of the Streptococcus pneumoniae type 3 capsule-specific glycoside hydrolase of Paenibacillus species 32352

Bacillus circulans Jordan 32352 was isolated from decaying organic matter in the New Jersey soil in the early 1930s. This soil-dwelling bacterium produced an enzyme capable of degrading the type 3 capsular polysaccharide (Pn3P) of Streptococcus pneumoniae (Spn). Early reports of this enzyme, Pn3Pase, demonstrated its inducibility by, and specificity for Pn3P. We set out to identify and clone this enzyme for its recombinant expression and characterization. We first sequenced the genome of this bacterial species, and reclassified the Pn3Pase producing bacterium as Paenibacillus species 32352. We identified the putative protein of Pn3Pase through mass spectrometry-based proteomics and cloned the gene for recombinant expression. We then characterized the oligosaccharide products generated upon the enzymatic depolymerization of Pn3P. Sequence analysis suggests that this glycoside hydrolase belongs to a new carbohydrate-active enzyme GH family. To our knowledge, this is the only enzyme to demonstrate Pn3P depolymerization activity.

Paenibacillus helianthi sp. nov., a nitrogen fixing species isolated from the rhizosphere of Helianthus annuus L

Three facultatively anaerobic endospore-forming bacteria were isolated from the rhizosphere of sunflowers grown in fields of Rio Grande do Sul State, Brazil. The designated type strain P26E^T was previously identified as a sunflower growth promoting bacterium and is able to fix nitrogen and to excrete ammonia. According to analyses of 16S rRNA gene sequences, P26E^T presented similarity values above 98.8% in relation to Paenibacillus azotifigens NF2-4-5^T, Paenibacillus graminis RSA19^T, Paenibacillus jilunlii Be17^T, Paenibacillus salinicaeni LAM0A28^T, and Paenibacillus sonchi X19-5^T. Phylogenetic reconstructions based on 16S rRNA gene and core proteome data showed that the strains P26E^T, P3E and P32E form a distinct clade, which did not include any type strain of the currently described Paenibacillus species. Also, genomic comparisons using average nucleotide identity (ANI), Orthologous ANI and in silico DNA-DNA hybridization revealed similarity ranges below the recommended thresholds when the three isolates from sunflower were compared to their close relatives. The DNA G + C content of strain P26E^T was determined to be 49.4 mol%. The major cellular fatty acids are anteiso-C_15:0 and iso-C_15:0, representing about 58 and 14% of the total fatty acids in P26E^T, respectively. Based on different taxonomic genomic metrics, phylogeny, and phenotypic data, we propose that strain P26E^T (= DSM 102269 = BR10509) represents a novel species within the genus Paenibacillus, for which the name Paenibacillus helianthi sp. nov. is proposed.

Paenibacillus crassostreae sp. nov., isolated from the Pacific oyster Crassostrea gigas

A Gram-stain-positive, endospore-forming, rod-shaped, aerobic bacterium, designated LPB0068^T, was isolated from a Pacific oyster (Crassostrea gigas) in Korea. This isolate was found to share the highest 16S rRNA gene sequence similarity with Paenibacillus macquariensis subsp. macquariensis DSM 2^T (98.1 %) and Paenibacillus macquariensis subsp. defensor JCM 14954^T (98.0 %). To establish the genomic relatedness of this isolate to its phylogenetic neighbours, its genome sequence and those of Paenibacillus antarcticus CECT 5836^T, P. macquariensis subsp. macquariensis DSM 2^T, P. macquariensis subsp. defensor JCM 14954^T, and Paenibacillus glacialis DSM 22343^T were determined. The low average nucleotide identity and digital DNA-DNA hybridization values exhibited by LPB0068^T in relation to the other strains in this analysis revealed that it is distinct from other Paenibacillus species. The genome of strain LPB0068^T consists of one chromosome and three circular plasmids, and had a DNA G+C content of 40.0 mol%. The major respiratory quinone was menaquinone-7 and the diagnostic diamino acid in the cell-wall peptidoglycan was meso-diaminopimelic acid. The major polar lipids consisted of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, one unidentified phospholipid, one unidentified glycolipid, and two unidentified polar lipids. The major cellular fatty acids were anteiso-C15 : 0, C14 : 0, and C16 : 0. Based on genomic, phylogenetic, and phenotypic characteristics, this strain was clearly distinguished from other Paenibacillus species with validly published names and should therefore be classified as a novel species of the genus. The name Paenibacillus crassostreae sp. nov. is proposed, the type strain of which is LPB0068^T (=KACC 18694^T=JCM 31183^T).

Paenibacillus ihbetae sp. nov., a cold-adapted antimicrobial producing bacterium isolated from high altitude Suraj Tal Lake in the Indian trans-Himalayas

The assessment of bacterial diversity and bioprospection of the high-altitude lake Suraj Tal microorganisms for potent antimicrobial activities revealed the presence of two Gram-stain-variable, endospore-forming, rod-shaped, aerobic bacteria, namely IHBB 9852^T and IHBB 9951. Phylogenetic analysis based on 16S rRNA gene sequence showed the affiliation of strains IHBB 9852^T and IHBB 9951 within the genus Paenibacillus, exhibiting the highest sequence similarity to Paenibacillus lactis DSM 15596^T (97.8% and 97.7%) and less than 95.9% similarity to other species of the genus Paenibacillus. DNA-DNA relatedness among strains IHBB 9852^T and IHBB 9951 was 90.2%, and with P. lactis DSM 15596^T, was 52.7% and 52.4%, respectively. The novel strains contain anteiso-C_15:0, iso-C_15:0, C_16:0 and iso-C_16:0 as major fatty acids, and phosphatidylglycerol, phosphatidylethanolamine and diphosphatidylglycerol were predominant polar lipids. The DNA G+C content for IHBB 9852T and IHBB 9951 was 52.1 and 52.2mol%. Based on the results of phenotypic and genomic characterisations, we concluded that strains IHBB 9852^T and IHBB 9951 belong to a novel Paenibacillus species, for which the name Paenibacillus ihbetae sp. nov. is proposed. The type strain is IHBB 9852^T (=MTCC 12459^T=MCC 2795^T=JCM 31131^T=KACC 19072^T; DPD TaxonNumber TA00046) and IHBB 9951 (=MTCC 12458=MCC 2794=JCM 31132=KACC 19073) is a reference strain.

Recovery of metallo-tolerant and antibiotic resistant psychrophilic bacteria from Siachen glacier, Pakistan

Cultureable bacterial diversity of previously unexplored Siachen glacier, Pakistan, was studied. Out of 50 isolates 33 (66%) were Gram negative and 17 (34%) Gram positive. About half of the isolates were pigment producers and were able to grow at 4-37°C. 16S rRNA gene sequences revealed Gram negative bacteria dominated by Proteobacteria (especially γ-proteobacteria and β-proteobacteria) and Flavobacteria. The genus Pseudomonas (51.51%, 17) was dominant among γ- proteobacteria. β-proteobacteria constituted 4 (12.12%) Alcaligenes and 4 (12.12%) Janthinobacterium strains. Among Gram positive bacteria, phylum Actinobacteria, Rhodococcus (23.52%, 4) and Arthrobacter (23.52%, 4) were the dominating genra. Other bacteria belonged to Phylum Firmicutes with representative genus Carnobacterium (11.76%, 2) and 4 isolates represented 4 genera Bacillus, Lysinibacillus, Staphylococcus and Planomicrobium. Most of the Gram negative bacteria were moderate halophiles, while most of the Gram positives were extreme halophiles and were able to grow up to 6.12 M of NaCl. More than 2/3 of the isolates showed antimicrobial activity against multidrug resistant S. aureus, E. coli, Klebsiella pneumonia, Enterococcus faecium, Candida albicans, Aspergillus flavus and Aspergillus fumigatus and ATCC strains. Gram positive bacteria (94.11%) were more resistant to heavy metals as compared to Gram negative (78.79%) and showed maximum tolerance against iron and least tolerance against mercury.

Paenibacillus yunnanensis sp. nov., isolated from Pu'er tea

A novel Gram-staining-positive, aerobic, endospore-forming, rod-shaped bacterial strain, YN2T, was isolated from ripened Pu'er tea. Phylogenetic analysis of 16S rRNA gene sequences showed that the strain represented a novel species of the genus Paenibacillus. The strains most closely related to strain YN2T were Paenibacillus vulneris JCM 18268T and Paenibacillus rigui JCM 16352T, with 16S rRNA similarities of 98.6 and 95.5 %, respectively. Chemotaxonomic data supported the affiliation of the new isolate to the genus Paenibacillus, including MK-7 as the major menaquinone, DNA G+C content of 51 mol%, cell-wall type A1γ (meso-diaminopimelic acid as the diagnostic diamino acid) and anteiso-C15 : 0 and iso-C16 : 0 as the major fatty acids. Major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylmonomethylethanolamine and phospholipid. Strain YN2T could be differentiated from recognized species of the genus Paenibacillus based on phenotypic characteristics, chemotaxonomic differences, phylogenetic analysis and DNA-DNA hybridization data. On the basis of evidence from this polyphasic study, Paenibacillus yunnanensis sp. nov., is proposed, with strain YN2T ( = CGMCC 1.12968T = JCM 30953T) as the type strain.

Cold active hydrolytic enzymes production by psychrotrophic Bacilli isolated from three sub-glacial lakes of NW Indian Himalayas

The diversity of culturable, cold-active enzymes producing Bacilli was investigated from three sub-glacial lakes of north western Indian Himalayas. Amplified ribosomal DNA restriction analysis (ARDRA) using three restriction enzymes Alu I, Msp I, and Hae III led to the clustering of 136 Bacilli into 26, 23, and 22 clusters at 75% similarity index from Chandratal Lake, Dashair Lake, and Pangong Lake, respectively. Phylogenetic analysis based on 16S rRNA gene sequencing led to the identification of 35 Bacilli that could be grouped in seven families viz.: Bacillaceae (48%), Staphylococcaceae (14%), Bacillales incertae sedis (13%), Planococcaceae (12%), Paenibacillaceae (9%), Sporolactobacillaceae (3%), and Carnobacteriaceae (1%), which included twelve different genera Bacillus, Desemzia, Exiguobacterium, Jeotgalicoccus, Lysinibacillus, Paenibacillus, Planococcus, Pontibacillus, Sinobaca, Sporosarcina, Staphylococcus, and Virgibacillus. Based on their optimal temperature for growth, 35 Bacilli were grouped as psychrophilic (11 strains), psychrotrophic (17 strains), or psychrotolerant (7 strains), respectively. The representative isolates from each cluster were screened for cold-active enzyme activities. Amylase, β-glucosidase, pectinase, and protease activities at 4 °C were detected in more than 80% of the strains while approximately 40, 31, 23, 14, 11, and 9% of strains possessed cellulase, xylanase, β-galactosidase, laccase, chitinase, and lipase activity, respectively. Among 35 Bacilli, Bacillus amyloliquefaciens, Bacillus marisflavi, Exiguobacterium indicum, Paenibacillus terrae, Pontibacillus sp., Sporosarcina globispora, and Sporosarcina psychrophila were efficient producers of different cold-active enzymes. These cold-adapted Bacilli could play an important role in industrial and agricultural processes.

Paenibacillus wenxiniae sp. nov., a nifH gene -harbouring endophytic bacterium isolated from maize

A novel Gram-positive, aerobic, motile, endospore-forming, rod-shaped bacterium, designated 373(T) was isolated from surface-sterilised root tissue of a maize planted in Fangshan District of Beijing, Peopole's Republic of China. A polyphasic taxonomic study was performed on the new isolate. On the basis of 16S rRNA gene sequence similarity studies, this isolate belongs to the genus Paenibacillus. The highest 16S rRNA gene sequence similarity was found between strain 373(T) and Paenibacillus hunanensis (98.1%), meanwhile the 16S rRNA gene sequence similarity between strain 373(T) and the type strains of other recognised members of the genus Paenibacillus were all below 95.6%. However, the DNA-DNA hybridization values between strain 373(T) and the type strain P. hunanensis DSM 22170(T) was 30.2%. The DNA G+C content of strain 373(T) was determined to be 46.0 mol%. The predominant respiratory quinone was identified as menaquinone-7 and the polar lipid profile was found to be composed of the major lipids diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The major fatty acids were found to consist of anteiso-C15: 0 (59.6%), anteiso-C17: 0 (12.8%) and C16: 0 (6.7%). The results of physiological and biochemical tests and minor differences in the fatty acid profiles allowed a clear phenotypic differentiation of strain 373(T) from the closely related species in this genus Paenibacillus. Strain 373(T) is concluded to represent a novel species within the genus Paenibacillus, for which the name Paenibacillus wenxiniae sp. nov. is proposed, with the type strain 373(T) (= CGMCC 1.15007 (T) = DSM100576 ).

Paenibacillus qingshengii sp. nov., isolated from a lead-zinc tailing

A novel bacterial strain, S1-9(T), was isolated from a lead-zinc tailing in Nanjing, Jiangsu Province, China. Cells of strain S1-9(T) were Gram-stain-negative, ellipsoidal endospore-forming, aerobic rods and motile by means of peritrichous flagella. On the basis of 16S rRNA gene sequence analysis, strain S1-9(T) was shown to belong to the genus Paenibacillus and the closest phylogenetic relatives were Paenibacillus glucanolyticus DSM 5162(T) (96.8% similarity), Paenibacillus lautus NRRL NRS-666(T) (96.5%) and Paenibacillus lactis MB 1871(T) (95.4%). The predominant menaquinone was MK-7. The major cellular fatty acids were anteiso-C15:0 and iso-C16:0. The polar lipid profile contained phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol, two unknown phospholipids and two unknown lipids. The total DNA G+C content of strain S1-9(T) was 49.9 mol%. Based on the low levels of DNA-DNA relatedness (ranging from 21.8 to 48.4%) to the type strains of the above species of the genus Paenibacillus and unique phenotypic characteristics, strain S1-9(T) is considered to represent a novel species of the genus Paenibacillus, for which the name Paenibacillus qingshengii sp. nov. is proposed. The type strain is S1-9(T) ( = CCTCC AB 2014290(T) = JCM 30613(T)).

Culturable and culture-independent bacterial diversity and the prevalence of cold-adapted enzymes from the Himalayan mountain ranges of India and Nepal

Bacterial diversity of soil samples collected from different geographical regions of Himalayan mountains was studied through culturable (13 samples) and culture-independent approaches (5 samples based on abundance of diversity indices in each ecological niche). Shannon-Wiener diversity index and total bacterial count ranged from 1.50 ± 0.1 to 2.57 ± 0.15 and 7.8 ± 1.6 × 10(5) to 30.9 ± 1.7 × 10(5) cfu ml(-1) of soil, respectively. Based on morphology and pigmentation, 406 isolates were selected by culturing in different cultivable media at various strengths and concentrations. All the strains were subjected to amplified ribosomal DNA restriction analysis and the representative isolates from each cluster were chosen for 16S rRNA gene sequence-based identification. Soil habitat in Himalayan foot hills was dominated by the genera Arthrobacter, Exiguobacterium, Bacillus, Cedecea, Erwinia, and Pseudomonas. Five 16S rRNA gene libraries from the selected five samples yielded 268 clones and were grouped into 53 phylotypes covering 25 genera including the genus of Ferribacterium, Rothia, and Wautersiella, which were reported for the first time in Himalayan tracks. Principal coordinates analysis indicates that all the clone libraries were clearly separated and found to be significantly different from each other. Further, extracellular investigation of cold-active enzymes showed activity of cellulase (23.71%), pectinase (20.24%), amylase (17.32%), phytase (13.87%), protease (12.72%), and lipase (23.71%) among the isolates. Four isolates namely Exiguobacterium mexicanum (BSa14), Exiguobacterium sibiricum (BZa11), Micrococcus antarcticus (BSb10), and Bacillus simplex (BZb3) showed multiple enzyme activity for five different types of enzymes. In addition, various genera like Exiguobacterium, Erwinia, Mycetecola, Cedecea, Pantoea, and Trichococcus have also shown novel hydrolytic enzyme activity in the Himalayan foothills.

Paenibacillus tibetensis sp. nov., a psychrophilic bacterium isolated from alpine swamp meadow soil

A novel psychrophilic strain, SSB001(T), was isolated from an alpine swamp meadow soil in Tibet, China, and identified as a representative of a novel phylogenetic subclade in the genus Paenibacillus , with Paenibacillus antarcticus (96.2%), Paenibacillus macquariensis (96.53%) and Paenibacillus glacialis (96.2%) as the most closely related species on the basis of 16S rRNA gene sequence analyses. The strain was distinguished from defined species of the genus Paenibacillus by further study of rpoB gene sequences, phenotypic characterization, cellular fatty acid composition, quinones, polar lipids and meso-diaminopimelic acid in the peptidoglycan. Based upon these results, we propose the strain as a representative of a novel species named Paenibacillus tibetensis sp. nov., with SSB001(T) ( =ACCC 19728(T) =DSM 29321(T)) as the type strain. The DNA G+C content (mol%) of strain SSB001(T) was 40.18 mol% (HPLC).

Paenibacillus guangzhouensis sp. nov., an Fe(III)- and humus-reducing bacterium from a forest soil

A Gram-reaction-variable, rod-shaped, motile, facultatively aerobic and endospore-forming bacterium, designated strain GSS02T, was isolated from a forest soil. Strain GSS02T was capable of reducing humic substances and Fe(III) oxides. Strain GSS02T grew optimally at 35 °C, at pH 78 and in the presence of 1 % NaCl. The predominant menaquinone was MK-7. The major cellular fatty acids were anteiso-C15 : 0 and iso-C16 : 0 and the polar lipid profile contained mainly phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylglycerol, with moderate amounts of two unknown aminophospholipids and a minor amount of one unknown lipid. The DNA G+C content was 53.4 mol%. Comparative 16S rRNA gene sequence analysis showed that strain GSS02T was related most closely to Paenibacillus terrigena JCM 21741T (98.1 % similarity). Mean DNA–DNA relatedness between strain GSS02T and P. terrigena JCM 21741T was 58.8±0.5 %. The phylogenetic, chemotaxonomic and phenotypic results clearly demonstrated that strain GSS02T belongs to the genus Paenibacillus and represents a novel species, for which the name Paenibacillus guangzhouensis sp. nov. is proposed. The type strain is GSS02T ( = KCTC 33171T = CCTCC AB 2013236T).

Genome-based comparative analyses of Antarctic and temperate species of Paenibacillus

Antarctic soils represent a unique environment characterised by extremes of temperature, salinity, elevated UV radiation, low nutrient and low water content. Despite the harshness of this environment, members of 15 bacterial phyla have been identified in soils of the Ross Sea Region (RSR). However, the survival mechanisms and ecological roles of these phyla are largely unknown. The aim of this study was to investigate whether strains of Paenibacillus darwinianus owe their resilience to substantial genomic changes. For this, genome-based comparative analyses were performed on three P. darwinianus strains, isolated from gamma-irradiated RSR soils, together with nine temperate, soil-dwelling Paenibacillus spp. The genome of each strain was sequenced to over 1,000-fold coverage, then assembled into contigs totalling approximately 3 Mbp per genome. Based on the occurrence of essential, single-copy genes, genome completeness was estimated at approximately 88%. Genome analysis revealed between 3,043-3,091 protein-coding sequences (CDSs), primarily associated with two-component systems, sigma factors, transporters, sporulation and genes induced by cold-shock, oxidative and osmotic stresses. These comparative analyses provide an insight into the metabolic potential of P. darwinianus, revealing potential adaptive mechanisms for survival in Antarctic soils. However, a large proportion of these mechanisms were also identified in temperate Paenibacillus spp., suggesting that these mechanisms are beneficial for growth and survival in a range of soil environments. These analyses have also revealed that the P. darwinianus genomes contain significantly fewer CDSs and have a lower paralogous content. Notwithstanding the incompleteness of the assemblies, the large differences in genome sizes, determined by the number of genes in paralogous clusters and the CDS content, are indicative of genome content scaling. Finally, these sequences are a resource for further investigations into the expression of physiological attributes that enable survival under extreme conditions and selection processes that affect prokaryotic genome evolution.

Paenibacillus doosanensis sp. nov., isolated from soil

A Gram-stain-positive, aerobic, endospore-forming bacterium, designated CAU 1055T, was isolated from soil and its taxonomic position was investigated using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequence comparison revealed that the strain formed a distinct lineage within the genus Paenibacillus and was most closely related to Paenibacillus contaminans CKOBP-6T (similarity, 95.2 %) and Paenibacillus terrigena A35T (similarity, 95.2 %). The levels of 16S rRNA gene sequence similarity with other species of the genus Paenibacillus , including the type species of the genus, Paenibacillus polymyxa IAM 13419T (similarity, 91.7 %), were all <94.6 %. Strain CAU 1055T contained MK-7 as the only isoprenoid quinone and anteiso-C15 : 0 and iso-C16 : 0 as the major fatty acids. The cell-wall peptidoglycan of strain CAU 1055T contained meso-diaminopimelic acid. The polar lipids were composed of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, lysyl-phospatidylglycerol and three unidentified aminophospholipids. The DNA G+C content was 48.3 mol%. The results of physiological and biochemical tests allowed phenotypic differentiation of strain CAU 1055T from closely related recognized species. On the basis of phenotypic data and phylogenetic inference, strain CAU 1055T should be classified in the genus Paenibacillus , as a member of a novel species, for which the name Paenibacillus doosanensis sp. nov. is proposed. The type strain is CAU 1055T ( = KCTC 33036T = CCUG 63270T).

Paenibacillus darwinianus sp. nov., isolated from gamma-irradiated Antarctic soil

A novel bacterium, strain Br(T), was isolated from gamma-irradiated soils of the Britannia drift, Lake Wellman Region, Antarctica. This isolate was rod-shaped, endospore forming, Gram-stain-variable, catalase-positive, oxidase-negative and strictly aerobic. Cells possessed a monotrichous flagellum. Optimal growth was observed at 18 °C, pH 7.0 in PYGV or R2A broth. The major cellular fatty acid was anteiso-C15 : 0 (63.4 %). Primary identified lipids included phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylglycerol. Total phospholipid was 60 % (w/w) of the total lipid extract. MK-7 was the dominant isoprenoid quinone. The genomic DNA G+C content was 55.6 mol%. Based on 16S rRNA gene sequence similarity, strain Br(T) clusters within the genus Paenibacillus with similarity values ranging from 93.9 to 95.1 %. Phylogenetic analyses by maximum-likelihood, maximum-parsimony and neighbour-joining methods revealed that strain Br(T) clusters with Paenibacillus daejeonensis (AF290916), Paenibacillus tarimensis (EF125184) and Paenibacillus pinihumi (GQ423057), albeit with weak bootstrap support. On the basis of phenotypic, chemotaxonomic and phylogenetic characteristics, we propose that strain Br(T) represents a novel species, Paenibacillus darwinianus sp. nov. The type strain is Br(T) ( = DSM 27245(T) = ICMP 19912(T)).

Paenisporosarcina indica sp. nov., a psychrophilic bacterium from a glacier, and reclassification of Sporosarcina antarctica Yu et al., 2008 as Paenisporosarcina antarctica comb. nov. and emended description of the genus Paenisporosarcina

A Gram-stain-positive, aerobic, spore-forming, rod-shaped bacterium, PN2T, was isolated from a soil sample collected near the Pindari glacier. It contained anteiso-C15 : 0, iso-C15 : 0 and C16 : 1ω7c alcohol as the predominant fatty acids, MK-7 as the major menaquinone and A4α type (l-Lys–d-Glu) peptidoglycan. Based on these characteristics, strain PN2T was assigned to the genus Paenisporosarcina . Phylogenetic analysis based on 16S rRNA gene sequence placed strain PN2T within the genus Paenisporosarcina and showed a sequence similarity of 98.5–99.0 % with members of this genus. Paenisporosarcina macmurdoensis CMS 21wT, Paenisporosarcina quisquiliarum SK 55T and Sporosarcina antarctica N-05T were identified as the most closely related species with 16S rRNA gene sequence similarities of 98.6 %, 99.0 % and 98.4 %, respectively. The values for DNA–DNA relatedness between strain PN2T and P. macmurdoensis , P. quisquiliarum and S. antarctica were below the 70 % threshold value (32.0 %, 42.0 % and 38.0 % respectively). In addition, strain PN2T exhibited a number of phenotypic differences from P. macmurdoensis , P. quisquiliarum and S. antarctica . Based on the cumulative differences, strain PN2T was identified as representing a novel species and the name Paenisporosarcina indica sp. nov. was proposed. The type strain of Paenisporosarcina indica sp. nov. is PN2T (LMG 23933T = JCM 15114T). Furthermore, based on the morphological and chemotaxonomic characteristics, the species Sporosarcina antarctica was reclassified as a species of the genus Paenisporosarcina and renamed Paenisporosarcina antarctica comb. nov. In addition, an emended description of the genus Paenisporosarcina is presented.

Paenibacillus catalpae sp. nov., isolated from the rhizosphere soil of Catalpa speciosa

A bacterial strain, designated D75(T), was isolated from the rhizosphere soil of Catalpa speciosa. Phylogenetic analysis based on the complete 16S rRNA gene sequence revealed that strain D75(T) was a member of the genus Paenibacillus. High levels of 16S rRNA gene sequence similarity were found between strain D75(T) and Paenibacillus glycanilyticus DS-1(T) (99.2 %), Paenibacillus xinjiangensis B538(T) (97.5 %) and Paenibacillus castaneae Ch-32(T) (97.2 %). The chemotaxonomic properties of strain D75(T) were consistent with those of the genus Paenibacillus: the cell-wall peptidoglycan type was based on meso-diaminopimelic acid (A1γ), the predominant menaquinone was MK-7, and the major fatty acids were anteiso-C15 : 0, iso-C16 : 0 and C16 : 0. However, levels of DNA-DNA relatedness between strain D75(T) and P. glycanilyticus NBRC 16618(T), P. xinjiangensis DSM 16970(T) and P. castaneae DSM 19417(T) were 35, 20 and 18 %, respectively. On the basis of phenotypic and chemotaxonomic analyses, phylogenetic data and DNA-DNA relatedness values, strain D75(T) is considered to represent a novel species of the genus Paenibacillus, for which the name Paenibacillus catalpae sp. nov. is proposed. The type strain is D75(T) ( = DSM 24714(T) = CGMCC 1.10784(T)).

Identification and characterization of psychrotolerant sporeformers associated with fluid milk production and processing

Psychrotolerant spore-forming bacteria represent a major challenge to the goal of extending the shelf life of pasteurized dairy products. The objective of this study was to identify prominent phylogenetic groups of dairy-associated aerobic sporeformers and to characterize representative isolates for phenotypes relevant to growth in milk. Analysis of sequence data for a 632-nucleotide fragment of rpoB showed that 1,288 dairy-associated isolates (obtained from raw and pasteurized milk and from dairy farm environments) clustered into two major divisions representing (i) the genus Paenibacillus (737 isolates, including the species Paenibacillus odorifer, Paenibacillus graminis, and Paenibacillus amylolyticus sensu lato) and (ii) Bacillus (n = 467) (e.g., Bacillus licheniformis sensu lato, Bacillus pumilus, Bacillus weihenstephanensis) and genera formerly classified as Bacillus (n = 84) (e.g., Viridibacillus spp.). When isolates representing the most common rpoB allelic types (ATs) were tested for growth in skim milk broth at 6°C, 6/9 Paenibacillus isolates, but only 2/8 isolates representing Bacillus subtypes, grew >5 log CFU/ml over 21 days. In addition, 38/40 Paenibacillus isolates but only 3/47 Bacillus isolates tested were positive for β-galactosidase activity (including some isolates representing Bacillus licheniformis sensu lato, a common dairy-associated clade). Our study confirms that Paenibacillus spp. are the predominant psychrotolerant sporeformers in fluid milk and provides 16S rRNA gene and rpoB subtype data and phenotypic characteristics facilitating the identification of aerobic spore-forming spoilage organisms of concern. These data will be critical for the development of detection methods and control strategies that will reduce the introduction of psychrotolerant sporeformers and extend the shelf life of dairy products.

Bacterial diversity of soil in the vicinity of Pindari glacier, Himalayan mountain ranges, India, using culturable bacteria and soil 16S rRNA gene clones

Three 16S rRNA gene clone libraries (P1L, P4L and P8L) were constructed using three soil samples (P1S, P4S and P8S) collected near Pindari glacier, Himalayas. The three libraries yielded a total of 703 clones. Actinobacteria, Firmicutes and Proteobacteria were common to the three libraries. In addition to the above P1L and P8L shared the phyla Acidobacteria, Bacteroidetes, Gemmatimonadetes and Planctomycetes. Phyla Chlamydiae, Chlorobi, Chloroflexi, Dictyoglomi, Fibrobacteres, Nitrospirae, Verrucomicrobia, candidate division SPAM and candidate TM7s TM7a phylum were present only in P1L. Rarefaction analysis indicated that the bacterial diversity in P4S and P8S soil samples was representative of the sample. Principal component analysis (PCA) revealed that P1S and P8S were different from P4S soil sample. PCA also indicated that arsenic content, pH, Cr and altitude influence the observed differences in the percentage of specific OTUs in the three 16S rRNA gene clone libraries. The observed bacterial diversity was similar to that observed for other Himalayan and non-polar cold habitats. A total of 40 strains of bacteria were isolated from the above three soil samples and based on the morphology 20 bacterial strains were selected for further characterization. The 20 bacteria belonged to 12 different genera. All the isolates were psychro-, halo- and alkalitolerant. Amylase and urease activities were detected in majority of the strains but lipase and protease activities were not detected. Long chain, saturated, unsaturated and branched fatty acids were predominant in the psychrotolerant bacteria.