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Alginate is a major extra polymeric substance in the biofilm formed by mucoid Pseudomonas aeruginosa. It is the main proven perpetrator of lung infections in patients suffering from cystic fibrosis. Alginate lyases are very important in the treatment of cystic fibrosis. This study evaluated the role of standalone and in conjugation, effect of alginate lyase of SG4 + isolated from Paenibacillus lautus in enhancing in vitro bactericidal activity of gentamicin and amikacin on mucoid P. aeruginosa. Using Response Surface Methodology (RSM) alginate lyase SG4 + production was optimized in shake flask and there 8.49-fold enhancement in enzyme production. In fermenter, maximum growth (10.15 mg/ml) and alginate lyase (1.46 International Units) production, 1.71-fold was increased using Central Composite Design (CCD). Further, fermentation time was reduced from 48 to 20 h. To the best of our knowledge this is the first report in which CCD was used for fermenter studies to optimize alginate lyase production. The K m and V max of purified enzyme were found to be 2.7 mg/ml and 0.84 mol/ml-min, respectively. The half-life (t 1/2 ) of purified alginate lyase SG4 + at 37 °C was 180 min. Alginate lyase SG4 + in combination with gentamicin and amikacin eradiated 48.4- 52.3% and 58- 64.6%, alginate biofilm formed by P. aeruginosa strains, respectively. The study proves that alginate lyase SG4 + has excellent exopolysaccharide disintegrating ability and may be useful in development of potent therapeutic agent to treat P. aeruginosa biofilms., (© 2024. The Author(s) under exclusive licence to Sociedade Brasileira de Microbiologia.)

Antibiotics have been applied to honey bee (Apis mellifera) hives for decades to treat Paenibacillus larvae, which causes American foulbrood disease and kills honey bee larvae. One of the few antibiotics approved in apiculture is tylosin tartrate. This study examined how a realistic hive treatment regimen of tylosin affected the gut microbiota of bees and susceptibility to a bacterial pathogen. Tylosin treatment reduced bacterial species richness and phylogenetic diversity and reduced the absolute abundances and strain diversity of the beneficial core gut bacteria Snodgrassella alvi and Bifidobacterium spp. Bees from hives treated with tylosin died more quickly after being fed a bacterial pathogen (Serratia marcescens) in the laboratory. We then tested whether a probiotic cocktail of core bee gut species could bolster pathogen resistance. Probiotic exposure increased survival of bees from both control and tylosin-treated hives. Finally, we measured tylosin tolerance of core bee gut bacteria by plating cultured isolates on media with different tylosin concentrations. We observed highly variable responses, including large differences among strains of both S. alvi and Gilliamella spp. Thus, probiotic treatments using cultured bee gut bacteria may ameliorate harmful perturbations of the gut microbiota caused by antibiotics or other factors. IMPORTANCE The antibiotic tylosin tartrate is used to treat honey bee hives to control Paenibacillus larvae, the bacterium that causes American foulbrood. We found that bees from tylosin-treated hives had gut microbiomes with depleted overall diversity as well as reduced absolute abundances and strain diversity of the beneficial bee gut bacteria Snodgrassella alvi and Bifidobacterium spp. Furthermore, bees from treated hives suffered higher mortality when challenged with an opportunistic pathogen. Bees receiving a probiotic treatment, consisting of a cocktail of cultured isolates of native bee gut bacteria, had increased survival following pathogen challenge. Thus, probiotic treatment with native gut bacteria may ameliorate negative effects of antibiotic exposure.

Stored rice and rice products are prone to contamination by pathogenic fungi and bacteria such as Aspergillus niger, Bacillus cereus, and Paenibacillus amylolyticus. Treatment with antimicrobial essential oils (EOs) and irradiation are options to control spoilage organisms. Microbial samples with or without fumigation with an oregano/thyme EO mixture were irradiated at 0.5, 0.75, 1.0, 1.5, 2.0, 2.5, 3.0 and 3.5 kGy for calculation of a D 10 value. The relative sensitivity was calculated as the ratio of D10 values for the irradiation plus oregano and thyme EO combination and irradiation alone treatments. In all cases, irradiation plus fumigation with the oregano and thyme EO mixture showed increased efficacy compared with irradiation alone. The relative sensitivity of γ-ray irradiation against A. niger was 1.22, 1.33, and 1.24 for radiation dose rates of 10.445, 4.558, and 0.085 kGy/h, respectively, however against B. cereus it was 1.28, 1.45, and 1.49, and against P. amylolyticus it was 1.35, 1.33, and 1.38, for respective γ-ray irradiation dose rates. The relative sensitivity of X-ray irradiation against A. niger, B. cereus, and P. amylolyticus was 1.63, 1.21, and 1.31, respectively, at the X-ray dose rate of 0.76 kGy/h. The results showed that the relative sensitivity of γ-ray irradiation was higher against the two bacteria than the fungus, whereas X-ray showed higher sensitivity against the fungus than the two bacteria. There was no consistent positive or negative relationship between dose rate and relative sensitivity. The results demonstrated the potential of an oregano and thyme EOs mixture as an antimicrobial agent and its efficacy to increase the radiosensitization of A. niger, B. cereus, and P. amylolyticus during γ-ray or X-ray irradiation treatments., Competing Interests: Declaration of competing interest There is no conflict of interest., (Published by Elsevier Ltd.)

The checkerboard method was used to study the potential interactions between eight essential oils (Basil, Cinnamon, Eucalyptus, Mandarin, Oregano, Peppermint, Tea tree, and Thyme) when used as antibacterial agents against Bacillus cereus LSPQ 2872 and Paenibacillus amylolyticus ATCC 9995. The minimum inhibitory concentration (MIC) of each essential oil (EO) and the fractional inhibitory concentration (FIC) index for the binary combinations of essential oils (EOs) were determined. According to FIC index values, some of the compound binary combinations showed an additive effect; however, Thyme/Tea tree and Cinnamon/Thyme EOs exhibited a synergistic effect against P. amylolyticus and B. cereus, respectively. Cinnamon/Thyme EOs mixture exhibited no interactive effect against P. amylolyticus, but a synergistic effect against B. cereus. The combination of Oregano/Thyme EOs displayed the best antibacterial activity and showed a synergistic effect against B. cereus and P. amylolyticus bacteria. The Oregano/Thyme EOs mixture has potential application in food preservation to reduce the contamination of B. cereus and P. amylolyticus., Competing Interests: Declaration of competing interest All authors of the manuscript state that there is no conflict of interest., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Microbial flocculant (MBF), an environmentally friendly water treatment agent, can be widely used in various water treatments. However, its use is limited by low yield and high cost. This problem can be solved by clarifying its biosynthesis mechanism and regulating it. Paenibacillus shenyangensis A9, a flocculant-producing bacterium, was used to produce polysaccharide-type MBFA9 by regulating the nitrogen source (nitrogen adequacy/nitrogen deficiency). In this study, RNA-Seq high-throughput sequencing technology and bioinformatic approaches were used to investigate the fermentation and biosynthesis of polysaccharide-type MBFA9 by regulating the nitrogen source (high nitrogen/low nitrogen) in the flocculant-producing bacteria Paenibacillus shenyangensis A9. Differentially expressed genes, functional clustering, and functional annotation of key genes were assessed. Then the MBFA9 biosynthesis and metabolic pathway were reconstructed. Our results showed that when cultured under different nitrogen conditions, bacterial strain A9 had a greater ability to synthesize polysaccharide-type MBFA9 under low nitrogen compared to high nitrogen conditions, with the yield of MBFA9 reaching 4.2 g/L at 36 h of cultivation. The quality of transcriptome sequencing data was reliable, with a matching rate of 85.38% and 85.48% when L36/H36 was mapped to the reference genome. The total expressed genes detected were 4719 and 4730, with 265 differentially expressed genes. The differentially expressed genes were classified into 3 categories: molecular function (MF), cell component (CC), and biological process (BP), and can be further divided into 22 subcategories. There were 192 upregulated genes and 73 downregulated genes, with upregulation being predominant under low nitrogen. UDP-Gal, UDP-Glc, UDP-GlcA, and UDP-GlcNAc, which are in the polysaccharide metabolic pathway, could all be used as precursors for MBFA9 biosynthesis, and murA, wecB, pgm, galU/galF, fcl, gmd, and glgC were the main functional genes capable of affecting the growth of bacteria and the biosynthesis of MBF. Results from this study provide evidence that high-level expression of key genes in MBFA9 biosynthesis, regulation, and control can achieve MBFA9 directional synthesis for large-scale applications.

A moderate thermophilic dibenzofuran (DF) degrader, strain 4B1, was isolated from dioxin-contaminated soil in Vietnam under thermophilic condition. A 16S rRNA gene sequence analysis assigned the strain to genus Paenibacillus. The optimum growth temperature of strain 4B1 was 45°C with a doubling time of 2.7 h in the presence of DF as a sole carbon and energy source. The rate of its growth and DF-degradation were approximately 3-fold higher than those of a reference Paenibacillus sp. strain. The 4B1 strain degraded 89% of 1000 mg L -1 DF within 48 h cultivation at the optimum temperature. TBLASTN analysis based on its draft genome sequence revealed that this strain possessed a dbf gene cluster. The open reading frames (dbfA1A2RBC) in the cluster shared 99-100% identity with those of Paenibacillus sp. YK5, indicating that DF was likely degraded by an angular dioxygenation pathway in strain 4B1. Four genes in the dbf gene cluster (dbfA1A2BC) were partially induced by DF, which was observed by semi-quantitative RT-PCR. Quantitative PCR analysis of dbfA1 transcripts, encoding the alpha subunit of DF dioxygenase, indicated that dbfA1 was expressed 4-times higher than that of strain YK5 at 45°C. These results suggest that the faster growth and degradation of DF in strain 4B1 could be due to differences in transcriptional regulation of dbf cluster genes., (Copyright © 2019. Published by Elsevier B.V.)

Chlorothalonil is a commonly used fungicide to control the karnal bunt caused by Tilletia indica Mitra in wheat production from the Yaqui Valley, Mexico. Here, the effect of Chlorothalonil on the growth of 132 bacterial strains associated with wheat rhizosphere from the Yaqui Valley was evaluated, as well as their ability to produce indoles. Thirty-three percent of the evaluated strains were inhibited by Chlorothalonil, being Bacillus and Paenibacillus the most inhibited genera, observing an inhibition >50% of their strains. In addition, 49% of the inhibited strains showed the ability to produce indoles (>5 μg/mL), where the genus Bacillus was the most abundant (80%). The remaining strains (67%) were tolerant to the evaluated fungicide, but only 37% of those showed the ability to produce indoles, which could be considered as Plant Growth Promoting Rhizobacteria (PGPR). These results showed that Chlorothalonil is not only an antifungal compound but also inhibits the growth of bacterial strains with the ability to produce indoles. Thus, the intensive application of fungicides to agro-systems needs more validation in order to develop sustainable agricultural practices for food production.

The reductive detoxification of microbes is of significant importance as toxic high oxidation-state metals are ubiquitous in the environment. As a protective interface, extracellular polymeric substances (EPS) are known to play an important role in reducing the toxicity, the relative contribution of different EPS fractions in the process of microbial reductive detoxification remains not to be understood. In this study, we used toxic gold ions (Au 3+ ) and EPS fractions from Paenibacillus mucilaginosus as an example to quantitatively assess the relative contribution of different EPS fractions in the process of the reductive detoxification. At different concentrations of EPS (300 mg/L to 500 mg/L), B-EPS contributed higher reductive ratio (10.6%±0.6% to 25.9%±0.3%) for reducing the toxicity of Au 3+ , while it was lower (1.7%±0.3% to 5.4%±0.6%) for L-EPS. Confronted with the attack of the Au 3+ ions (0 ppm-180 ppm), sugars in B-EPS had a more positive metabolic response than proteins (secreted sugars/ proteins>1) against the toxicity of Au 3+ . Ultimately, FTIR and electrochemical titration analyses showed that the detoxification process of microbial EPS was mainly mediated by the aldehyde groups of sugars in B-EPS. This study contributed a quantitative understanding for the role of different fractions of EPS in microbial defense against the attack of toxic metal ions., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Interests in biosurfactant in industrial and environmental applications have increased considerably in recent years, owing to their potential benefits over synthetic counterparts. The present study aimed at analyzing the stability and oil removal efficiency of a new lipopeptide biosurfactant produced by Paenibacillus sp. D9 and its feasibility of its use in biotechnological applications. Paenibacillus sp. D9 was evaluated for optimal growth conditions and improved production yield of lipopeptide biosurfactant with variations in different substrate parameters such as carbon (C), nitrogen (N), C:N: ratio, metal supplements, pH, and temperature. Enhanced biosurfactant production was observed when using diesel fuel and ammonium sulfate as carbon and nitrogen source respectively. The maximum biosurfactant yield of 4.11 g/L by Paenibacillus sp. D9 occurred at a C/N ratio of 3:1, at pH 7.0, 30 °C, 4.0 mM MgSO 4 , and 1.5% inoculum size. The D9 biosurfactant was found to retain surface-active properties under the extreme conditions such as high thermal, acidic, alkaline, and salt concentration. The ability to emulsify further emphasizes its potential usage in biotechnological application. Additionally, the lipopeptide biosurfactant exhibited good performance in the degradation of highly toxic substances when compared with chemical surfactant, which proposes its probable application in biodegradation, microbial-enhanced oil recovery or bioremediation. Furthermore, the biosurfactants were effective in a test to stimulate the solubilization of hydrophobic pollutants in both liquid environments removing 49.1 to 65.1% diesel fuel including hydrophobic pollutants. The study highlights the usefulness of optimization of culture parameters and their effects on biosurfactant production, high stability, improved desorption, and solubilization of hydrophobic pollutants.

This study shows that sequential introduction of drug resistance mutations substantially increased enzyme production in Paenibacillus agaridevorans The triple mutant YT478 ( rsmG Gln225→stop codon, rpsL K56R, and rpoB R485H), generated by screening for resistance to streptomycin and rifampin, expressed a 1,100-fold-larger amount of the extracellular enzyme cycloisomaltooligosaccharide glucanotransferase (CITase) than the wild-type strain. These mutants were characterized by higher intracellular S -adenosylmethionine concentrations during exponential phase and enhanced protein synthesis activity during stationary phase. Surprisingly, the maximal expression of CITase mRNA was similar in the wild-type and triple mutant strains, but the mutant showed greater CITase mRNA expression throughout the growth curve, resulting in enzyme overproduction. A metabolome analysis showed that the triple mutant YT478 had higher levels of nucleic acids and glycolysis metabolites than the wild type, indicating that YT478 mutant cells were activated. The production of CITase by the triple mutant was further enhanced by introducing a mutation conferring resistance to the rare earth element, scandium. This combined drug resistance mutation method also effectively enhanced the production of amylases, proteases, and agarases by P. agaridevorans and Streptomyces coelicolor This method also activated the silent or weak expression of the P. agaridevorans CITase gene, as shown by comparisons of the CITase gene loci of P. agaridevorans T-3040 and another cycloisomaltooligosaccharide-producing bacterium, Paenibacillus sp. strain 598K. The simplicity and wide applicability of this method should facilitate not only industrial enzyme production but also the identification of dormant enzymes by activating the expression of silent or weakly expressed genes. IMPORTANCE Enzyme use has become more widespread in industry. This study evaluated the molecular basis and effectiveness of ribosome engineering in markedly enhancing enzyme production (>1,000-fold). This method, due to its simplicity, wide applicability, and scalability for large-scale production, should facilitate not only industrial enzyme production but also the identification of novel enzymes, because microorganisms contain many silent or weakly expressed genes which encode novel antibiotics or enzymes. Furthermore, this study provides a new mechanism for strain improvement, with a consistent rather than transient high expression of the key gene(s) involved in enzyme production., (Copyright © 2018 American Society for Microbiology.)

Paenibacillus assamensis is a bacterium usually found in warm springs. We detected P. assamensis in a man with suspected tularemia. The strain isolated from the man's knee joint fluid was identified as P. assamensis after analysis of a homologous sequence of the 16S rRNA gene.

The present investigation was to study the effect of different non-ionic surfactants (Tween-80, Tween-60, Tween-40, Tween-20, Triton X-100) and a rhamnolipid biosurfactant on the degradation of fluorene by Paenibacillus sp. PRNK-6. An enhancement in the growth, as well as fluorene utilization by this strain were observed in the presence of biosurfactant and non-ionic surfactants except Tween-20 and Triton X-100. Triton X-100 and Tween-20 were toxic to this bacterium. The strain PRNK-6 utilized 75% of fluorene (280mg/L) in 24h in an unamended condition. On the other hand, the complete utilization of higher concentration fluorene (320mg/L) by this strain was noticed when the medium was amended with Tween-80 (1.5% v/v) within 24h of incubation. Whereas, 90.6%, 96.5% and 96.7% of fluorene (280mg/L) was utilized when amended with Tween-60 (3.5% v/v), Tween-40 (3% v/v) and biosurfactant (25mg/L) respectively. Biosurfactant promoted the fluorene degradation potential of PRNK-6 as 96.2% of 320mg/L fluorene was degraded within 24h. Further, the added tween series surfactants and a biosurfactant have increased the cell surface hydrophobicity of the PRNK-6. Thus correlating with the enhanced degradation of the fluorene., (Copyright © 2018 Elsevier Inc. All rights reserved.)

The ecology of antibiotic resistance involves the interplay of a long natural history of antibiotic production in the environment, and the modern selection of resistance in pathogens through human use of these drugs. Important components of the resistome are intrinsic resistance genes of environmental bacteria, evolved and acquired over millennia, and their mobilization, which drives dissemination in pathogens. Understanding the dynamics and evolution of resistance across bacterial taxa is essential to address the current crisis in drug-resistant infections. Here we report the exploration of antibiotic resistance in the Paenibacillaceae prompted by our discovery of an ancient intrinsic resistome in Paenibacillus sp. LC231, recovered from the isolated Lechuguilla cave environment. Using biochemical and gene expression analysis, we have mined the resistome of the second member of the Paenibacillaceae family, Brevibacillus brevis VM4, which produces several antimicrobial secondary metabolites. Using phylogenomics, we show that Paenibacillaceae resistomes are in flux, evolve mostly independent of secondary metabolite biosynthetic diversity, and are characterized by cryptic, redundant, pseudoparalogous, and orthologous genes. We find that in contrast to pathogens, mobile genetic elements are not significantly responsible for resistome remodeling. This offers divergent modes of resistome development in pathogens and environmental bacteria.

The study aimed to identify an effective phosphate-solubilizing and organochlorine pesticide-tolerant bacterial strain(s). A total of 50 phosphate-solubilizing bacterial (PSB) strains were isolated from pesticide-stressed soil. Ten isolates showing higher solubilization were selected for organochlorine pesticides (endosulfan, aldrin, and lindane) tolerance. The strain IITISM08 showed the maximum potential of phosphorous solubilization in Pikovaskya agar medium (solubilization index = 3.2) and in broth medium (348 ± 2 μg mL -1 ) and tolerated up to 250 μg mL -1 of organochlorine pesticides. During phosphorous solubilization, the presence of functional group and organic acid production were also observed using FT-IR and HPLC. The plant growth-promoting (PGP) traits of the strain IITISM08 was highly inhibited in presence of endosulfan among the three organochlroine pesticides. The strain IITISM08 degraded aldrin (79%), lindane (68%), and endosulfan (51%) at a concentration of 50 μg mL -1 . The strain IITISM08 was identified using 16S rDNA gene sequencing as Paenibacillus sp. (IITISM08). The study revealed that the strain IITISM08 can be used as PGP candidate even under organochlorine pesticide-stressed condition.

Bee disease caused by spore-forming Paenibacillus larvae and Paenibacillus alvei is a serious problem for honey production. Thus, there is an ongoing effort to find an effective agent that shows broad biocidal activity with minimal environmental hazard. In this study, the biocidal effect of maltose reduced silver nanoparticles (AgNPs) is evaluated against American foulbrood and European foulbrood pathogens. The results demonstrate that the maltose reduced AgNPs are excellent short and long-term biocides against P. larvae isolates. The long-term effect suggests that the Ag + ions are released from the AgNPs with increasing time in a controlled manner.

A bacterial strain showing strong antifungal activity was isolated from yellow loess and was identified as Paenibacillus kribbensis CU01. Insoluble mucoidal polymers were separated from M9 culture medium via low-speed centrifugation. Most antifungal activity was associated with substances in the insoluble precipitate, which was purified by reverse phase high performance liquid chromatography. Purified fractions were analyzed using matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry. Two major ion peaks with mass-to-charge ratio values (m/z) at 883.6 and 897.6 were revealed. After alkaline hydrolysis and sequence analysis, two cyclic depsipeptides were identified as, fusaricidin A and fusaricidin B. Their production was significantly increased by the addition of glucose, Fe 2+ , and Mn 2+ to M9 medium. Maximum concentrations of produced fusaricidin A and fusaricidin B at flask-scale comprised 460 mg L -1 and 118 mg L -1 , respectively: the highest production concentrations yet reported in the literature. This demonstrates that P. kribbensis CU01 has enormous commercial potential for the mass production of fusaricidin., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

To characterize red pigment-producing bacteria (RPPB) regularly released during oviposition by red palm weevil (RPW), RPPB were recovered from eggs deposited in apples supplied as substrate for oviposition. The presence of RPPB was also detected from gut, the reproductive apparatus of dissected adult and virgin insects and from pupal cases collected within infested palms. RPPB were also identified all along the tissue of these palms. Analysis of the 16S rDNA, gyrB, rpoB, recA, and groEL sequences assigned RPPB to the species Serratia marcescens. RPPB exhibited an antimicrobial activity assessed by the agar well diffusion method against a number of gram-positive and gram-negative bacteria. In this study, we first report the identification of a red pigment-producing S. marcescens as extracellular symbiont of RPW. Route of transmission, detection within different organs, and a wide spread along the infested palm tissue, suggested S. marcescens is present as extracellular symbiont in different developmental stages of the RPW. Additionally, the antimicrobial activity exhibited versus Bacillus spp., Paenibacillus spp., and Lysinibacillus spp., reported as insect pathogens and potential candidates for biocontrol agents, could ascribe for S. marcescens a potential protective role., (© 2016 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.)

The composition of the volatile fraction of Malva sylvestris var. mauritiana (L.) Boiss. (Malvaceae) was investigated. This plant species was cultivated in the southeastern Alps as an ingredient for herbal teas and infusions. Flowers and leaves were collected at the end of the summer season and separately steam- distilled to obtain two volatile oils, the yields of which were 0.019% for leaves and 0.012% for flowers. After GC-FID and GC-MS analyses, the two oils -revealed differences in the nature and especially in the proportion of their components, which were aldehydes, alcohols, phenolics, esters, hydrocarbons and acids. Eugenol was the single most abundant compound in the leaves, totalling 46.7% of the total oil, followed by phytol with 34.4%. Flowers showed a predominance of hydrocarbons, among which the anteiso branched-chain saturated hydrocarbon, 3-methyl tricosane, was the most abundant compound, accounting for 14.9% of the total volatiles. Eugenol ranked second with 10.3%, followed by the two linear-chain saturated hydrocarbons pentacosane and tricosane forming 8.2 and 7.7% of the total oil, respectively. The occurrence and the relative abundance of compounds from various chemical classes such as phenolics, hydrocarbons and aromatic aldehydes and alcohols are discussed, together with some of their ecological implications. The obtained volatile oils were than tested against two major honeybee (Apis mellifera) pathogens, namely Paenibacillus larvae and Melissococcus plutonius, the causative agents of the American and the European foulbrood, respectively.

Among the strategies developed for contaminated groundwater bioremediation, those based on the use of bacteria adhering to inert supports and establishing biofilms have gained great importance in this field. Extractive membrane biofilm reactor (EMBFR) technology offers productive solutions for the removal of volatile and semi-volatile compounds. EMBFR technology is based on the use of extractive semipermeable membranes through which contaminants migrate to the biological compartment in which microorganisms with pollutant biotransformation and/or mineralization capacities can grow, forming an active biofilm on the membrane surface. The objective of this study was to assess the use of three bacterial strains (Paenibacillus sp. SH7 CECT 8558, Agrobacterium sp. MS2 CECT 8557, and Rhodococcus ruber EE6 CECT 8612), as inoculum in a lab-scale EMBFR running for 28 days under aerobic conditions to eliminate methyl tert-butyl ether (MTBE) from water samples. Three different hydraulic retention times (1, 6, and 12 h) were employed. MTBE degradation values were determined daily by a gas GC-MS technique, as well as suspended bacterial growth. The biofilm established by the bacterial strains on the semipermeable membrane was detected by Field-Emission Scanning Electron Microscopy (FESEM) at the end of each experiment. The acute toxicity of the treated effluents and biomedium was determined by Microtox © assay (EC 50 ).The results achieved from the MTBE degradation, biofilm formation, and toxicity analysis indicated that bacterial strains MS2 and EE6 were the best options as selective inoculum, although further research is needed, particularly with regard to their possible use as a mixed culture. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1238-1245, 2016., (© 2016 American Institute of Chemical Engineers.)

The bacterial flagellar motor is a sophisticated nanomachine embedded in the cell envelope and powered by an electrochemical gradient of H(+), Na(+), or K(+)across the cytoplasmic membrane. Here we describe a new member of the bacterial flagellar stator channel family (MotAB1 of Paenibacillus sp. TCA20 (TCA-MotAB1)) that is coupled to divalent cations (Ca(2+)and Mg(2+)). In the absence of divalent cations of alkaline earth metals, no swimming was observed in Paenibacillus sp. TCA20, which grows optimally in Ca(2+)-rich environments. This pattern was confirmed by swimming assays of a stator-free Bacillus subtilis mutant expressing TCA-MotAB1. Both a stator-free and major Mg(2+)uptake system-deleted B. subtilis mutant expressing TCA-MotAB1 complemented both growth and motility deficiency under low Mg(2+)conditions and exhibited [Mg(2+)]in identical to that of the wild-type. This is the first report of a flagellar motor that can use Ca(2+)and Mg(2+)as coupling ions. These findings will promote the understanding of the operating principles of flagellar motors and molecular mechanisms of ion selectivity.

Paenibacillus larvae is the causal agent of the honey bee disease American Foulbrood. Two enhanced protocols that allow the activity of antimicrobial peptides to be tested against P. larvae are presented. Proof of principle experiments demonstrate that the honey bee antimicrobial peptide defensin 1 is active in both assays., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Polymyxin E, produced by Paenibacillus polymyxa, is an important antibiotic normally against Gram-negative pathogens. In this study, we found that polymyxin E can kill its producer P. polymyxa, a Gram-positive bacterium, by disrupting its cell membrane. Membrane damage was clearly revealed by detecting the leakage of intracellular molecules. The observation using scanning electron microscopy also supported that polymyxin E can destroy the cell membrane and cause an extensive cell surface alteration. On the other hand, divalent cations can give protection against polymyxin E. Compared with Mg2+, Ca2+ can more effectively alleviate polymyxin E-induced damage to the cell membrane, thus remarkably increasing the P. polymyxa survival. Our findings would shed light on a not yet described bactericidal mechanism of polymyxin E against Gram-positive bacteria and more importantly the nature of limited fermentation output of polymyxin E from P. polymyxa.

Ninety-six strains of Paenibacillus larvae, causative agent of American foulbrood in honey bee (Apis mellifera) larvae, collected from Connecticut, USA (CT), honey bees, and 12 P. larvae strains not from CT, were genotyped via ERIC-PCR and XbaI-RFLP analysis. All CT-isolates, five strains isolated in South America, three strains from North America (not CT), and one strain isolated in Australia grouped into the ERIC I genotype. Three P. larvae formerly subsp. pulvifaciens strains grouped into ERIC III and IV genotypes. XbaI-RFLP genotyping showed three genotypes within the CT-isolates, and two were identified as XbaI-RFLP Type I and III. The third XbaI-RFLP genotype (Type Ib) represented one of four new XbaI-RFLP genotypes identified. Comparison of genotype results for the P. larvae strains tested was used to develop a correlation between ERIC-PCR genotyping and XbaI-RFLP genotyping. Sixteen CT-isolates were tetracycline-resistant and demonstrated PCR amplification using oligonucleotide primers for tetL. All 16 isolates grouped within XbaI-RFLP Type Ib, suggesting limited introduction of a tetracycline-resistant strain into CT.

Endolysins, which are peptidoglycan-degrading enzymes expressed during the terminal stage of the reproduction cycle of bacteriophages, have great potential to control Gram-positive pathogens. This work describes the characterization of a novel endolysin (PlyPl23) encoded on the genome of Paenibacillus larvae phage phiIBB_Pl23 with high potential to control American foulbrood. This bacterial disease, caused by P. larvae, is widespread in North America and Europe and causes important economic losses in apiculture. The restriction to antibiotic residues in honey imposed by the EU legislation hinders its therapeutic use to combat American foulbrood and enforces the development of alternative antimicrobial methods. The new endolysin described herein has an N-acetylmuramoyl-L-alanine amidase catalytic domain and exhibits a broad-spectrum activity against common P. larvae genotypes. Moreover, the enzyme displays high antimicrobial activity in a range of pH that matches environmental conditions (pH between 5.0 and 7.0), showing its feasible application in the field. At pH 7.0, a concentration of 0.2 μM of enzyme was enough to lyse 104 CFU.mL-1 of P. larvae in no more than 2 h. The presence of sucrose and of the substances present in the larvae gut content did not affect the enzyme activity. Interestingly, an increase of activity was observed when PlyPl23 was previously incubated in royal jelly. Furthermore, in vivo safety evaluation assays demonstrated that this enzyme is not toxic to the bee larvae. The present work describes for the first time an endolysin encoded in a P. larvae phage that presents high potential to integrate a commercial product to control the problematic American foulbrood.

Unlabelled: Swarming bacteria are challenged by the need to invade hostile environments. Swarms of the flagellated bacterium Paenibacillus vortex can collectively transport other microorganisms. Here we show that P. vortex can invade toxic environments by carrying antibiotic-degrading bacteria; this transport is mediated by a specialized, phenotypic subpopulation utilizing a process not dependent on cargo motility. Swarms of beta-lactam antibiotic (BLA)-sensitive P. vortex used beta-lactamase-producing, resistant, cargo bacteria to detoxify BLAs in their path. In the presence of BLAs, both transporter and cargo bacteria gained from this temporary cooperation; there was a positive correlation between BLA resistance and dispersal. P. vortex transported only the most beneficial antibiotic-resistant cargo (including environmental and clinical isolates) in a sustained way. P. vortex displayed a bet-hedging strategy that promoted the colonization of nontoxic niches by P. vortex alone; when detoxifying cargo bacteria were not needed, they were lost. This work has relevance for the dispersal of antibiotic-resistant microorganisms and for strategies for asymmetric cooperation with agricultural and medical implications., Importance: Antibiotic resistance is a major health threat. We show a novel mechanism for the local spread of antibiotic resistance. This involves interactions between different bacteria: one species provides an enzyme that detoxifies the antibiotic (a sessile cargo bacterium carrying a resistance gene), while the other (Paenibacillus vortex) moves itself and transports the cargo. P. vortex used a bet-hedging strategy, colonizing new environments alone when the cargo added no benefit, but cooperating when the cargo was needed. This work is of interest in an evolutionary context and sheds light on fundamental questions, such as how environmental antibiotic resistance may lead to clinical resistance and also microbial social organization, as well as the costs, benefits, and risks of dispersal in the environment., (Copyright © 2015 Finkelshtein et al.)

American foulbrood (AFB) is a serious worldwide spreading disease in bees caused by Paenibacillus larvae. Plants extracts are known to decrease or inhibit the growth of these bacteria. The purpose of this study was to evaluate the antimicrobial activity of Calendula. officinalis, Cariniana domestica, and Nasturtium officinale extracts against the P. larvae and to evaluate the toxicity of the extracts in bees. In vitro activity against P. larvae of the extracts was evaluated by micro dilution method and the minimal inhibitory concentrations (MICs) were also determined. The concentrations used in the toxicity test were established based on the MIC values and by the spraying application method. The P. larvae was susceptible to the evaluated crude extract of C. officinalis and N. officinale. To C. domestica, only the ethyl acetate (EtAc) fraction and n-butanol (BuOH) fractions had activity against P. larvae. Toxicity analysis in bees showed no toxicity for N. officinale crude extract and for C. domestica BuOH fraction during 15 days of treatment, however, some deaths of bees occurred during the first three days of treatment with C. officinalis and C. domestica EtAc fraction. The results with these species were firstly described and showed that N. officinale crude extract and C. domestica BuOH fraction both presented not toxic effects in the concentration tested by the spraying application method, and can be a useful alternative for treatment or prevention of AFB.

Achyrocline satureioides extracts were tested in vitro against the growth of Paenibacillus larvae. Four different extracts were obtained by liquid-liquid extraction from an aqueous-ethyl alcohol macerate of the aerial parts of the plant. The biological activity was tested by the broth microdilution technique. Hexane extract showed the highest activity (minimum inhibitory concentration = 0.060 ± 0.037 mg/mL). Transmission electron microscopy experiments showed that the main effect exerted by the hexane extract on the cell was at the cellular membrane level. The hexane extract was analyzed by thin-layer chromatography, and the activity of its components was tested by bioautography. Four growth inhibition zones were observed in the bioautographic experiments (using hexane-acetone (7:3) as mobile phase), with that at Rf = 0.57 showing the largest zone of inhibition. High-performance liquid chromatographic experiments, using ultraviolet and electrospray ionization coupled to tandem mass spectrometric detection, showed the presence of one compound with a m/z ratio of 442, which may be related to phloroglucinols α-pyrone compounds recently discovered. The high antibacterial activity of the hexane extract and of the isolated compound determined in this work may be useful for the development of future new alternatives for the treatment of American foulbrood.

Background: Contamination of tomatoes by Salmonella can occur in agricultural settings. Little is currently understood about how agricultural inputs such as pesticide applications may impact epiphytic crop microflora and potentially play a role in contamination events. We examined the impact of two materials commonly used in Virginia tomato agriculture: acibenzolar-S-methyl (crop protectant) and copper oxychloride (pesticide) to identify the effects these materials may exert on baseline tomato microflora and on the incidence of three specific genera; Salmonella, Xanthomonas and Paenibacillus., Results: Approximately 186 441 16S rRNA gene and 39 381 18S rRNA gene sequences per independent replicate were used to analyze the impact of the pesticide applications on tomato microflora. An average of 3 346 677 (634 892 974 bases) shotgun sequences per replicate were used for metagenomic analyses., Conclusion: A significant decrease in the presence of Gammaproteobacteria was observed between controls and copper-treated plants, suggesting that copper is effective at suppressing growth of certain taxa in this class. A higher mean abundance of Salmonella and Paenibacillus in control samples compared to treatments may suggest that both systemic and copper applications diminish the presence of these genera in the phyllosphere; however, owing to the lack of statistical significance, this could also be due to other factors. The most distinctive separation of shared membership was observed in shotgun data between the two different sampling time-points (not between treatments), potentially supporting the hypothesis that environmental pressures may exert more selective pressures on epiphytic microflora than do certain agricultural management practices., (© 2014 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.)

Propolis is a substance derived from antimicrobial plant resins that honey bees use in the construction of their nests. Propolis use in the hive is an important component of honey bee social immunity and confers a number of positive physiological benefits to bees. The benefits that bees derive from resins are mostly due to their antimicrobial properties, but it is unknown how the diversity of antimicrobial activities among resins might impact bee health. In our previous work, we found that resins from different North American Populus spp. differed in their ability to inhibit in vitro growth of the bee bacterial pathogen Paenibacillus larvae. The goal of our current work was to characterize the antimicrobial activity of propolis from 12 climatically diverse regions across the US against the bee pathogens P. larvae and Ascosphaera apis and compare the metabolite profiles among those samples using LC-MS-based metabolomic methods. Samples differed greatly in their ability to inhibit both bacterial and fungal growth in vitro, but propolis from Nevada, Texas, and California displayed high activity against both pathogens. Interestingly, propolis from Georgia, New York, Louisiana, and Minnesota were active against A. apis, but not very active against P. larvae. Metabolomic analysis of regional propolis samples revealed that each sample was compositionally distinct, and LC-FTMS profiles from each sample contained a unique number of shared and exclusive peaks. Propolis from Aspen, CO, Tuscon, AZ, and Raleigh, NC, contained relatively large numbers of exclusive peaks, which may indicate that these samples originated from relatively unique botanical sources. This is the first study to characterize how the diversity of bee preferred resinous plants in the US may affect bee health, and could guide future studies on the therapeutic potential of propolis for bees., (Copyright © 2014 Elsevier Inc. All rights reserved.)

A universal method to enhance productivity and viscosity of bacterial exopolysaccharides was developed. The technique was based on the principle that ampicillin can inhibit the biosynthesis of peptidoglycan, which shares a common synthetic pathway with that of bacterial exopolysaccharides. Serial passages of three typical representatives of bacterial EPS-producing strains, namely Sphingomonas elodea, Xanthomonas campestris, and Paenibacillus elgii, were subjected to ampicillin, which was used as a stressor and a mutagen. These mutant strains are advantageous over other strains because of two major factors. First, all of the resulting strains were almost mutants with increase in EPS productivity and viscosity. Second, isolated serial strains showed different levels of increase in EPS production and viscosity to satisfy the different requirements of practical applications. No differences were observed in the monosaccharide composition produced by the mutant and parent strains; however, high-viscosity mutant strains exhibited higher molecular weights. The results confirmed that the developed method is a controlled universal one that can improve exopolysaccharides productivity and viscosity., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Cellular redox status and oxygen availability influence the product formation. Herein, decreasing agitation speed or adding vitamin C (Vc) achieved the 2,3-BDL yield of 0.40 g g(-1) or 0.39 g g(-1)glucose under batch fermentation, respectively. To our knowledge, this is the highest 2,3-BDL yield reported so far for Paenibacillus polymyxa without adding acetic acid. The NADH/NAD(+) ratio and 2,3-BDL titer could be increased significantly by reducing the agitation speed or adding Vc, indicating that the enhancement of 2,3-BDL is closely associated with the adjustment of NADH/NAD(+) ratio. Especially, Vc addition elevated the 2,3-BDL titer from 43.66 g L(-1) to 71.71 g L(-1) within 54 h under fed-batch fermentation. This is the highest titer of 2,3-BDL so far reported for P. polymyxa from glucose fermentation. This work provides a new strategy to improve 2,3-BDL production and helps us to understand the responses of P. polymyxa to extracellular oxidoreduction potential., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The in vitro inhibitory potential of 50 extracts from various species of the flowering plant genus Hypericum was investigated using the Kirby-Bauer disk diffusion susceptibility test against Paenibacillus larvae, a spore-forming, Gram-positive bacterial pathogen that causes American foulbrood (AFB), a lethal disease affecting honeybee brood worldwide. Of the tested extracts, 14 were identified as highly active against P. larvae as compared to the activity of the positive control, indicating the presence of highly potent antibacterial compounds in the extracts. Examination of these extracts using TLC and HPLC/MS analyses revealed the presence of acylphloroglucinol and filicinic-acid derivatives. Six pure compounds isolated from these extracts, viz., hyperforin (1), uliginosin B (2), uliginosin A (3), 7-epiclusianone (4), albaspidin AA (5), and drummondin E (6), displayed strong antibacterial activity against the vegetative form of P. larvae (MIC ranging from 0.168-220 μM). Incubation of P. larvae spores with the lipophilic extract of Hypericum perforatum and its main acylphloroglucinol constituent 1 led to the observation of significantly fewer colony forming units as compared to the negative control, indicating that the acylphloroglucinol scaffold represents an interesting lead structure for the development of new AFB control agents., (Copyright © 2014 Verlag Helvetica Chimica Acta AG, Zürich.)

Aims: The aims of this study were to evaluate the effectiveness of nisin A to control the growth of spore-forming bacteria, Bacillus and Paenibacillus, in chilled high-fat, milk pudding and to reduce heat treatment to improve aroma and flavour., Methods and Results: Nisin A was added to milk pudding containing 5·0 and 7·5% fat to final concentrations of 40, 80, 120 and 240 IU ml(-1). Spores from Bacillus thuringiensis, Bacillus cereus and Paenibacillus jamilae were inoculated into samples at 10 spores ml(-1) prior to pasteurization at 130°C for 2 s. Milk pudding without inoculation was pasteurized using less heat condition (100, 110 and 120°C for 2 s) to measure the effect of adjusting the ingredients to prevent naturally occurring bacteria. The viable cells during storage at 15, 20 and 30°C showed nisin A inhibited spiked bacteria to varying degrees depending on species, sensitivities to nisin A concentration and fat content, and inhibited natural populations at 80 IU g(-1) nisin A in 5·0% fat and at 120 IU g(-1) in 7·5% fat milk pudding. An aroma compound analysis and organoleptic assessment showed processing at 110 and 120°C decreased the temperature-dependent unpleasant odours, for example, reduced dimethyl sulfide and dimethyl disulfide by 1·2-1·5 times and increased rankings in taste tests compared with 130°C treated pudding., Conclusions: Nisin A was found to be effective as a natural preservative to control spoilage bacteria in high-fat milk pudding and extend its shelf life, when using reduced heat treatments to improve the flavour and aroma without compromising food safety., Significance and Impact of the Study: This is the first report showing nisin A is effective in reducing spoilage bacteria in high-fat, chilled dessert, milk pudding. Therefore, nisin A can be used to improve milk puddings to satisfy both industry and consumer demand for food quality and safety., (© 2014 The Society for Applied Microbiology.)

Paenibacillus larvae, the causal agent of American foulbrood disease in honeybees, acquires tetracycline-resistance via native plasmids carrying known tetracycline-resistance determinants. From three P. larvae tetracycline-resistant strains isolated from honeys, 5-kb-circular plasmids with almost identical sequences, designated pPL373 in strain PL373, pPL374 in strain PL374, and pPL395 in strain PL395, were isolated. These plasmids were highly similar (99%) to small tetracycline-encoding plasmids (pMA67, pBHS24, pBSDMV46A, pDMV2, pSU1, pAST4, and pLS55) that replicate by the rolling circle mechanism. Nucleotide sequences comparisons showed that pPL373, pPL374, and pPL395 mainly differed from the previously reported P. larvae plasmid pMA67 in the oriT region and mob genes. These differences suggest alternative mobilization and/or conjugation capacities. Plasmids pPL373, pPL374, and pPL395 were individually transferred by electroporation and stably maintained in tetracycline-susceptible P. larvae NRRL B-14154, in which they autonomously replicated. The presence of nearly identical plasmids in five different genera of gram-positive bacteria, i.e., Bhargavaea, Bacillus, Lactobacillus, Paenibacillus, and Sporosarcina, inhabiting diverse ecological niches provides further evidence of the genetic transfer of tetracycline resistance among environmental bacteria from soils, food, and marine habitats and from pathogenic bacteria such as P. larvae.

A diverse set of parasites and pathogens affects productivity and survival of Apis mellifera honeybees. In beekeeping, traditional control by antibiotics and molecules of synthesis has caused problems with contamination and resistant pathogens. In this research, different Laurus nobilis extracts are tested against the main honeybee pests through an integrated point of view. In vivo effects on bee survival are also evaluated. The ethanol extract showed minimal inhibitory concentration (MIC) values of 208 to 416 μg/mL, having the best antimicrobial effect on Paenibacillus larvae among all substances tested. Similarly, this leaf extract showed a significant antiparasitic activity on Varroa destructor, killing 50 % of mites 24 h after a 30-s exposure, and on Nosema ceranae, inhibiting the spore development in the midgut of adult bees ingesting 1 × 10(4) μg/mL of extract solution. Both ethanol extract and volatile extracts (essential oil, hydrolate, and its main component) did not cause lethal effects on adult honeybees. Thus, the absence of topical and oral toxicity of the ethanol extract on bees and the strong antimicrobial, microsporicidal, and miticidal effects registered in this study place this laurel extract as a promising integrated treatment of bee diseases and stimulates the search for other bioactive phytochemicals from plants.

Paenibacillus macerans TKU029 can produce exopolysaccharides (EPSs; 3.46 g/L) and a biosurfactant (1.78 g/L) in a medium with 2 % (w/v) squid pen powder as the sole carbon/nitrogen source. The biosurfactant can reduce the surface tension of water from 72.30 to 35.34 mN/m at a concentration of 2.76 g/L and reach an emulsification index of 56 % after a 24-h reaction with machine oil. This biosurfactant is stable at 121 °C for 20 min, over a pH range from 3 to 11, and in <5 % salt solutions. It also shows significant antimicrobial activity, which remains active after treatment at 121 °C and at pH values from 4 to 10, against Escherichia coli BCRC13086, Staphylococcus aureus BCRC10780, Fusarium oxysporum BCRC32121 and Aspergillus fumigatus BCRC30099. Furthermore, human skin shows from 37.3 to 44.3 % hydration after being treated with TKU029 EPSs for 180 min. These results imply that EPSs and the biosurfactant from this strain have potential in cosmetics, for removal of oil contamination, and as antimicrobial agents.

In the current study, the processing conditions required for the inactivation of Paenibacillus polymyxa and relevant spoilage microorganisms by high hydrostatic pressure (HHP) treatment on apricot, peach, and pear pieces in sucrose (22°Brix) solution were assessed. Accordingly, the shelf-life was determined by evaluating both the microbiological quality and the sensory characteristics (taste, odor, color, and texture) during refrigerated storage after HHP treatment. The microbiological shelf-life of apricots, peaches, and pears was prolonged in the HHP-treated products in comparison with the untreated ones. In all HHP-treated packages for apricots, peaches, and pears, all populations were below the detection limit of the method (1 log CFU/g) and no growth of microorganisms was observed until the end of storage. Overall, no differences of the L*, a*, or b* value among the untreated and the HHP-treated fruit products were observed up to the time at which the unpressurized product was characterized as spoiled. HHP treatment had no remarkable effect on the firmness of the apricots, peaches, and pears. With regard to the sensory assessment, the panelists marked better scores to HHP-treated products compared to their respective controls, according to taste and total evaluation during storage of fruit products.

A bacterium capable of methanethiol (MT) degradation was enriched and isolated by employing activated sewage sludge as the inoculum in a mineral medium containing MT. The isolate was identified as Paenibacillus polymyxa CZ05 through a Biolog test and 16S rDNA sequencing. This strain can utilize both organic and inorganic media and thrives at pH 4 to 9. The batch culture showed that the strain can degrade MT better in the No. 4 medium than in the No. 1 medium. A series-operating biotrickling filter with lava stone as the carrier was employed to test the application of P. polymyxa CZ05 in the removal of MT in simulated biogas. Long-term experiments showed that a high concentration of MT (60 ppm) was efficiently removed (99.5%) by the biotrickling filters at EBRT 30 s. The addition of hydrogen sulfide decreased the MT removal rate because the dissolved oxygen competed with MT., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The wide number of industrial processes applying cellulases highlights the importance of discovering robust enzymes able to work under harsh conditions. In this study, carboxymethyl cellulase (CMCase) activity of Paenibacillus tarimensis was characterized. A high activity was observed in pH range 3.0-10.5 and 9 mM-5 M NaCl. In high salt buffer at 80°C, >80% and >76% of relative activity was retained at 20% of the ionic liquids (ILs) [EMIM]Ac and [BMIM]Cl; while >40% was detected with 40% [BMIM]Cl. Five CMCases were detected by renaturing SDS-PAGE. Their activity was retained in presence of 1.7 up to 5 M NaCl (for CMC1) or 4.6 M KCl; 5% organic solvents or 10 mM bivalent ions, EDTA and heavy metals; under neutral and halo-alkaline conditions. These cellulases stabile and highly functional under harsh conditions are promising candidates for application in detergents, textiles, paper/pulp industry; and simultaneous ILs treatment-saccharification of lignocellulose., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The deposition of antimicrobial plant resins in honey bee, Apis mellifera, nests has important physiological benefits. Resin foraging is difficult to approach experimentally because resin composition is highly variable among and between plant families, the environmental and plant-genotypic effects on resins are unknown, and resin foragers are relatively rare and often forage in unobservable tree canopies. Subsequently, little is known about the botanical origins of resins in many regions or the benefits of specific resins to bees. We used metabolomic methods as a type of environmental forensics to track individual resin forager behavior through comparisons of global resin metabolite patterns. The resin from the corbiculae of a single bee was sufficient to identify that resin's botanical source without prior knowledge of resin composition. Bees from our apiary discriminately foraged for resin from eastern cottonwood (Populus deltoides), and balsam poplar (P. balsamifera) among many available, even closely related, resinous plants. Cottonwood and balsam poplar resin composition did not show significant seasonal or regional changes in composition. Metabolomic analysis of resin from 6 North American Populus spp. and 5 hybrids revealed peaks characteristic to taxonomic nodes within Populus, while antimicrobial analysis revealed that resin from different species varied in inhibition of the bee bacterial pathogen, Paenibacillus larvae. We conclude that honey bees make discrete choices among many resinous plant species, even among closely related species. Bees also maintained fidelity to a single source during a foraging trip. Furthermore, the differential inhibition of P. larvae by Populus spp., thought to be preferential for resin collection in temperate regions, suggests that resins from closely related plant species many have different benefits to bees.

American foulbrood (AFB) is a bacterial disease caused by the spore-forming, grampositive bacterium Paenibacillus larvae, which affects honeybee broods worldwide. The aim of this work was to compare the Epsilometer test (Etest) to the agar dilution method for testing a collection of 22 P. larvae strains to tetracycline by using MYPGP and Iso- Sensitest agars. Results showed that a categorical agreement of 100% was found when using Iso-Sensitest, while a categorical agreement of 86.36% was found (with 3 minor errors) when MYPGP was tested. In conclusion, the Etest could be a rapid and reliable method for testing MIC values of tetracycline in P. larvae only when used in combination with Iso-Sensitest agar. Nevertheless, these results should be confirmed with future studies involving a larger number of isolates., (Copyright © 2013 Asociación Argentina de Microbiología. Publicado por Elsevier España. All rights reserved.)

Bacteria often use sophisticated cooperative behaviours, such as the development of complex colonies, elaborate biofilms and advanced dispersal strategies, to cope with the harsh and variable conditions of natural habitats, including the presence of antibiotics. Paenibacillus vortex uses swarming motility and cell-to-cell communication to form complex, structured colonies. The modular organization of P. vortex colony has been found to facilitate its dispersal on agar surfaces. The current study reveals that the complex structure of the colony is generated by the coexistence and transition between two morphotypes--'builders' and 'explorers'--with distinct functions in colony formation. Here, we focused on the explorers, which are highly motile and spearhead colonial expansion. Explorers are characterized by high expression levels of flagellar genes, such as flagellin (hag), motA, fliI, flgK and sigD, hyperflagellation, decrease in ATP (adenosine-5'-triphosphate) levels, and increased resistance to antibiotics. Their tolerance to many antibiotics gives them the advantage of translocation through antibiotics-containing areas. This work gives new insights on the importance of cell differentiation and task distribution in colony morphogenesis and adaptation to antibiotics., (© 2013 The Authors. Environmental Microbiology published by John Wiley & Sons Ltd and Society for Applied Microbiology.)

The optimization, purification and characterization of bioflocculant produced by Paenibacillus elgii B69 were investigated. The bioflocculant was an exopolysaccharide composed of glucose, glucuronic acid, mannose and xylose. The maximum bioflocculant production was about 25.63 g/L achieved with sucrose at 51.35 g/L, peptone at 6.78 g/L and yeast extract at 0.47 g/L optimized by response-surface methodology. In addition, a series of experiments was performed to investigate the flocculation activities towards kaolin clay, dyeing pigment, heavy metal ion, and real wastewater and the result indicated the new bioflocculant had high activities towards all the tested pollutions. These results showed its great potential for water pretreatment used in industry., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Paenibacillus larvae is the causative agent of American foulbrood (AFB), a disease affecting honey bee larvae. First- and second-instar larvae become infected when they ingest food contaminated with P. larvae spores. The spores then germinate into vegetative cells that proliferate in the midgut of the honey bee. Although AFB affects honey bees only in the larval stage, P. larvae spores can be distributed throughout the hive. Because spore germination is critical for AFB establishment, we analyzed the requirements for P. larvae spore germination in vitro. We found that P. larvae spores germinated only in response to l-tyrosine plus uric acid under physiologic pH and temperature conditions. This suggests that the simultaneous presence of these signals is necessary for spore germination in vivo. Furthermore, the germination profiles of environmentally derived spores were identical to those of spores from a biochemically typed strain. Because l-tyrosine and uric acid are the only required germinants in vitro, we screened amino acid and purine analogs for their ability to act as antagonists of P. larvae spore germination. Indole and phenol, the side chains of tyrosine and tryptophan, strongly inhibited P. larvae spore germination. Methylation of the N-1 (but not the C-3) position of indole eliminated its ability to inhibit germination. Identification of the activators and inhibitors of P. larvae spore germination provides a basis for developing new tools to control AFB.

The honeybee disease American foulbrood (AFB) is a serious problem since its causative agent (Paenibacillus larvae) has become increasingly resistant to conventional antibiotics. One of the feasible alternative treatments being used for control of this disease are plants extracts. The aim of the present work was to evaluate the effect of crude extract and fractions of Scutia buxifolia against six Paenibacillus species, including P. larvae, and its potential use for the control of AFB. In vitro activity of S. buxifolia samples against Paenibacillus species were evaluated by the disk diffusion and microdilution methods, and the minimal inhibitory concentration (MIC) were also determined. All Paenibacillus species were sensitive to crude extract and fractions of S. buxifolia. The dichloromethane (DC) fraction showed the better MIC (1.56 mg/mL), followed by ethyl acetate (EtAc) (6.25 mg/mL), n-butanol (BuOH) (25 mg/mL) and Crude extract (CE) (50 mg/mL). Toxic effect of S. buxifolia crude extracts and fractions against bees were also evaluated by the spraying application method of the same concentrations of MICs. The samples tested showed no toxic effects for the bees after 15 days of observation. These results are first time described for this species and showed that S. buxifolia presented a important activity against Paenibacillus species and proved to be a natural alternative for the prevention/control of AFB., (Copyright © 2012 Elsevier Inc. All rights reserved.)

All Paenibacillus 16S rDNA sequences, except for that of Paenibacillus massiliensis T7, formed a coherent cluster, distinct from Gram-positive nitrogen-fixing Clostridium pasteurianum and Heliobacterium chlorum. All Paenibacillus NifH sequences formed two main clusters. Cluster I encompassing the NifH sequences from most of members of Paenibacillus spp., such as Paenibacillus azotofixans NifH1 and NifH2, Paenibacillus polymyxa and Paenibacillus macerans. Cluster II including only P. azotofixans NifH3. Curiously, three copies of nifH genes of Paenibacillus sabine T27 clustered within P. azotofixans cluster I (NifH1 and NifH2). The effect of O2 and ammonium on nitrogenase activity was studied with 14 different nitrogen-fixing Paenibacillus strains. The optimal oxygen concentration level for all Paenibacillus strains is in the 0 to 0.05% range, similar to that for Klebsiella pneumoniae. In all Paenibacillus strains, the highest nitrogenase activity is obtained in the condition of 0-0.1 mM NH4Cl and the increase of NH4CI from 0.1 to 5 mM caused a rapid inhibition of nitrogenase activity. However, the inhibition was reversible in the presence of 200 mM NH4Cl in some Paenibacillus strains. It is the first time to use almost all of the recognized nitrogen-fixing Paenibacilus spp. to investigate the phylogeny of 16S rRNA and nifH genes. The data that the inhibition of O2 and ammonium on nitrogenase acitivity will provide a base for studying the molecular regulatory mechanism of nitrogen fixation in the genus Paenibacillus.

To investigate the expression patterns of chitinase isozymes on native-PAGE and SDS-PAGE gels Paenibacillus chitinolyticus MP-306 was cultured on culture media with and without chitin substrate. P. chitinolyticus MP-306 had a strong chitinolytic activity on colloidal chitin medium. Chitinase isozymes of MP-306 were expressed as six bands (CN1-CN6) on native-PAGE gels and thirteen bands (CS1-CS13) on SDS-PAGE gels after incubation in chitin medium. Three bands (CN1, CN2, and CN3) of chitinase isozymes of MP-306 on native-PAGE gels were expressed as nine bands (CS1, CS2, CS3, CS4, CS5, CS6, CS8, CS10, and CS13) of chitinase isozymes on SDS-PAGE gels. Three bands (CN4, CN5, and CN6) of chitinase isozymes of MP-306 were strongly inhibited by metal ions on native-PAGE and SDS-PAGE gels., (Copyright © 2012 Elsevier Ltd. All rights reserved.)