Effects of an EPS Biosynthesis Gene Cluster of Paenibacillus polymyxa WLY78 on Biofilm Formation and Nitrogen Fixation under Aerobic Conditions

Exopolysaccharides (EPS) are of high significance in bacterial biofilm formation. However, the effects of EPS cluster(s) on biofilm formation in Paenibacillus species are little known. In this study, we have shown that Paenibacillus polymyxa WLY78, a N2-fixing bacterium, can form biofilm. EPS is the major component of the extracellular matrix. The genome of P. polymyxa WLY78 contains two putative gene clusters (designated pep-1 cluster and pep-2 cluster). The pep-1 cluster is composed of 12 putative genes (pepO-lytR) co-located in a 13 kb region. The pep-2 cluster contains 17 putative genes (pepA-pepN) organized as an operon in a 20 kb region. Mutation analysis reveals that the pep-2 cluster is involved in EPS biosynthesis and biofilm formation. Disruption of the pep-2 cluster also leads to the enhancement of motility and change of the colony morphology. In contrast, disruption of the pep-1 cluster does not affect EPS synthesis or biofilm formation. More importantly, the biofilm allowed P. polymyxa WLY78 to fix nitrogen in aerobic conditions, suggesting that biofilm may provide a microaerobic environment for nitrogenase synthesis and activity.

Draft Genome Sequences of Five Paenibacillus Species of Dairy Origin

ABSTRACT Paenibacillus species are important spoilage organisms in the dairy industry. The genomes of five Paenibacillus species which were isolated from dairy products in Canada were sequenced using the Illumina MiSeq platform. Draft genomes ranging from 5.1 to 7.1 Mb with GC contents of 49 to 53% were generated.

Draft Genome Sequences of Bacillus and Paenibacillus Species Isolated from Seeds of Citrullus lanata (Watermelon), Cucurbita moschata (Butternut Squash), and Cucurbita pepo L. var. pepo L. (Pumpkin)

ABSTRACT Here, we announce the draft genome sequences of four endophytic bacilli isolated from surface-sterilized seeds of three cucurbit species, Bacillus sp. strains EKM417B and EKM420B (from Citrullus lanata [watermelon]) and EKM501B (from Cucurbita moschata [butternut squash]) and Paenibacillus sp. strain EKM301P (from Cucurbita pepo L. var. pepo L. [pumpkin]). These strains previously demonstrated biostimulant and biocontrol activities.

Environmental distribution of the neurotoxin l-BMAA in Paenibacillus species

The environmental distribution of the neurotoxic amino acid, 3-N-methyl-2,3-diaminopropanoic acid (BMAA), first isolated in 1967, was initially believed to be limited to tropical and subtropical plants of the genus Cycas. The seeds of one such species, which had been used historically on the Pacific island of Guam as a foodstuff, had a reputation for neurotoxicity. Some 40 years later the amino acid was detected in terrestrial and aquatic cyanobacteria and in other aquatic organisms. Overlooked was the discovery of BMAA in peptides of bizarre structure that had been isolated in 1975 from Paenibacillus pulvifaciens during a search for antibiotics. More recently (2014), peptides of similar structure were isolated from Paenibacillus larvae; this organism is causative of American Foulbrood, a lethal disease of honeybee colonies. These are interesting chemical and environmental observations, but knowledge of the bacterial distribution of BMAA is limited to just these two species of Paenibacillus, while more than 200 Paenibacillus spp. are known. Paenibacillus spp. are ever present naturally in the environment and are used agriculturally; recent research reports that some species infect human foods – including cow's milk – and have been isolated from human body fluids. We wish to stimulate interest in the environmental distribution of the neurotoxic BMAA in Paenibacillus spp. by drawing together previously isolated streams of research and by proposing experimental approaches by which this matter might be resolved.

Screening, characterization and molecular-genetical identification of a new bacterial strain Paenibacillus species

Bacterial variant PS-K-17 was isolated from wheat grain contaminated by polysaccharide-producing microbiota for further characterization. It was found that the isolate grown on agar slants and in submerged culture on media with specific substrates synthesized beta-galactosidase, amylase, protease, pectinase, cellulase, beta-glucanase, lipase (esterase), alginase, extracellular polysaccharides, and pigments, probably carotenoids. Based on cultural-morphological and physiological-biochemical properties and phylogenetic analysis of nucleotide sequences of 16S rRNA gene (access code MF443394 in GenBank) the bacterial culture was identified as Paenibacillus species PS-K-17. The studied isolate forms one phylogenetic branch with type strains Paenibacillus nicotianae (98.3 %), Paenibacillus hordei (98.2 %), Paenibacillus kyungheensis (97.9 %), holding wherein a separate position. Strain Paenibacillus sp. PS-K-17 may find use in biotechnology as a producer of extracellular polysaccharides and enzymes splitting plant polymeric substances as well as a component of microbial consortium-ingredient of a new complex feed additive.

Evolution and Functional Analysis of orf1 Within nif Gene Cluster from Paenibacillus graminis RSA19

Paenibacillus is a genus of Gram-positive, facultative anaerobic and endospore-forming bacteria. Genomic sequence analysis has revealed that a compact nif (nitrogen fixation) gene cluster comprising 9–10 genes nifBHDKENX(orf1)hesAnifV is conserved in diazotrophic Paenibacillus species. The evolution and function of the orf1 gene within the nif gene cluster of Paenibacillus species is unknown. In this study, a careful comparison analysis of the compositions of the nif gene clusters from various diazotrophs revealed that orf1 located downstream of nifENX was identified in anaerobic Clostridium ultunense, the facultative anaerobic Paenibacillus species and aerobic diazotrophs (e.g., Azotobacter vinelandii and Azospirillum brasilense). The predicted amino acid sequences encoded by the orf1 gene, part of the nif gene cluster nifBHDKENXorf1hesAnifV in Paenibacillus graminis RSA19, showed 60–90% identity with those of the orf1 genes located downstream of nifENX from different diazotrophic Paenibacillus species, but shared no significant identity with those of the orf1 genes from different taxa of diazotrophic organisms. Transcriptional analysis showed that the orf1 gene was expressed under nitrogen fixation conditions from the promoter located upstream from nifB. Mutational analysis suggested that the orf1 gene functions in nitrogen fixation in the presence of a high concentration of O2.