Pumilus Research Articles

Microbiolização de sementes de arroz com Bacillus spp. na redução de patógenos

As sementes são componentes essenciais da economia, nelas está contida a vida e a possibilidade de disseminação de doenças, sendo a sanidade importante para o desenvolvimento sadio de plantas com altos rendimentos. O trabalho objetivou-se avaliar a qualidade sanitária de sementes de arroz da variedade Bonança e a redução de fitopatógenos, utilizando a microbiolização de sementes com Bacillus macerans, B. polymyxa, B. pentothenticus, B. lentus, B. pumilus, B. stearothermophilus e Bacillus sp.. A sanidade das sementes foi avaliada pelo método Blotter Test. A redução da incidência dos fitopatógenos nas sementes foi analisada por microbiolização para cada isolado e posteriormente, as sementes foram semeadas em solo esterilizado. O delineamento experimental utilizado foi o inteiramente casualizado nos experimentos em laboratório e em casa de vegetação. Avaliou-se a incidência e redução dos fitopatógenos em sementes e plantas de arroz aos sete e quatorze dias após a semeadura. As sementes foram avaliadas em lupa para identificar colônias de fungos. Quanto às plantas, em cada época retirou-se 100 plantas e realizou-se a assepsia usual. Os resultados do teste in vitro as sementes de arroz variedade Bonança, microbiolizadas com os Bacillus spp., reduziram a incidência de Curvularia oryzae e Aspergillus niger. Nas plantas originadas das sementes microbiolizadas com os Bacillus spp., observou-se a redução da incidência de Curvularia oryzae, Aspergillus niger e Scopulariopsis sp. A ação dos isolados foi diferenciada quanto ao patógeno e o tempo após a microbiolização das sementes.

In silico characterization and structural modeling of the cyanide dihydratase enzyme CynD of Bacillus pumilus

In silico characterization and structural modeling of the cyanide dihydratase enzyme CynD of Bacillus pumilus

Differential Pattern of Arsenic Binding by the Cell Wall in Two ArseniteTolerant Bacillus Strains Isolated from Arsenic Contaminated Soil

Arsenite binding was evaluated in two Bacillus strains i.e., B. megaterium and B. pumilus, isolated from arsenic contaminated soil of Unnao district of Uttar Pradesh (India). Initial results showed that more than 90% of arsenite was removed by surface binding by the cell wall component in both the tested species of bacteria. Results on the concentration dependent arsenic binding in bacterial strains exhibited higher efficiency of arsenite binding in B. megaterium (qmax - 1000 mg g-1 protein) than B. pumilus (qmax - 666.7 mg g-1 protein). The pH optima for arsenic (As) binding in both B. megaterium (pH 6.0) and B. pumilis (pH 8.0) were found to be different. Results on temperature dependent arsenite binding by B. megaterium showed maximum binding at 30oC, while arsenic binding maxima in B. pumilus showed a broad temperature range (25oC to 35oC). The kinetic parameters on arsenite binding revealed that both the bacterial strains followed pseudo-second order kinetics. The As adsorption behavior of the bacterial strains was better explained by Langmuir isotherm rather than Freundlich model. Results of FTIR spectra on surface binding of As revealed major spectral changes in the band region of 1600 cm-1 to 800 cm-1 in case of B. megaterium, indicating involvement of mainly amines, alkenes and C-N functional groups. Whereas FTIR spectrum of B. pumilus showed changes in the band region of 3433 cm-1 to 2924 cm-1 , indicating the involvement of hydroxyl, alkanes, alkenes, amides and aromatic functional groups in the arsenic binding. A corollary of these results indicated differential binding of arsenite in both the Bacillus strains was on account of different arsenite binding ligands on cell surface as evident from the FTIR results as well as different pH and temperature optima.

Bacterial endophytes of weeds are effective biocontrol agents of Agrobacterium spp., Pectobacterium spp., and promote growth of tomato plants

Bacterial endophytes were isolated from native plants growing in a fallow field. Taxonomy of these bacteria, and their beneficial effects to plants, were determined. Seventeen strains were selected from a group of 73 isolates on the basis of origin, colony morphology and antagonistic properties and were characterized by 16S rRNA gene sequence and phylogenetic analyses. These strains were assayed in vivo against pathogenic strains of Agrobacterium and Pectobacterium spp. Their ability to improve plant growth was also evaluated. The Gram positive Bacillus amyloliquefaciens , B. cereus , B. methylotrophicus , B. pumilus and Curtobacterium flaccumfaciens and the Gram negative Pseudomonas brassicacearum were identified. The Bacillus and Pseudomonas were shared among five plant species while C. flaccumfaciens was isolated only from Euphorbia spp. Biocontrol activity of endophytic strains was evaluated on potato disks inoculated with Pectobacterium spp. and on tomato plants grown in sterile soil, root-bacterized with endophytes and stem inoculated with Agrobacterium spp. A reduction of soft rot caused by Pectobacterium spp. on three potato varieties treated with Bacillus s pp. strains was observed. Bacillus methylotrophicus strain OS4 strongly reduced gall development induced by Agrobacterium spp. and gave 100% germination of tomato seeds compared with 75.5% for the non-treated seeds. Pseudomonas brassicacearum strain PS1 enhanced tomato seed germination and increased plant growth parameters. These results indicate that native plants harbour various endophytic bacterial species that possess potentially valuable biocontrol and growth promotion activities.

Correction: Differentiation of Bacillus pumilus and Bacillus safensis Using MALDI-TOF-MS

Correction: Differentiation of Bacillus pumilus and Bacillus safensis Using MALDI-TOF-MS

CONTROL OF XANTHOMONAS CAMPESTRIS pv. VESICATORIA USING AGROINDUSTRIAL WASTE-BASED COMPOST

Here we review the suppressive capacity of 14 agroindustrial subproduct-based compost against the disease caused by Xanthomonas campestris pv. vesicatoria (Xcv) in tomato crops. The obtained results have shown that the in vitro compost’s suppressive effect on Xcv growth was mainly due to biotic factors, since sterilised compost samples were not effective. The most effective composts were 44TRI, 50, 51, 52 and 55, while the rest of them apparently did not affect the in vitro growth of the bacterium. When the same composts were applied in a tomato seedbed, the sample named 51 showed the most suppressive effect against the symptoms caused by the pathogen. Disease incidence reduction after this treatment reached 80%. In this case, a clear indirect relationship was detected between disease incidence and fresh weight losses of treated plants. Finally, the suppressive characteristics of an agroindustrial-based compost were improved after the inoculation with a biological control agent, a strain of Bacillus pumilus MSW231 known to be effective against Xcv. In this case, the isolation of the pathogen from infected plants was reduced up to 95% as compared to plants treated with another non-suppressive substrate. The present results indicate that the agroindustrial subproducts-based compost posseses an important suppressive effect towards the disease caused by Xcv, mainly due to biotic factors, and therefore it can be improved by the inoculation with biological control agents, worsened by sterilization and even modified by the inoculation with other biological control agents, so as to obtain an effective compost a la carte.

Isolation of salt tolerant endophytic and rhizospheric bacteria by natural selection and screening for promising plant growth-promoting rhizobacteria (PGPR) and growth vigour in tomato under sodic environment

The importance of plant growth promoting rhizobacteria in growth promotion and their ability to elicit ‘induced systemic tolerance’ against abiotic stresses has been documented. However, the performance of these microbes under various abiotic stresses especially saline-sodic conditions will be of great importance in the current agricultural scenario. In this study, we isolated 16 rhizobacteria through natural selection from saline sodic soils, and characterized them using morphological and biochemical parameters. These bacteria were assessed for their plant growth-promoting rhizobacteria (PGPR) traits like indole-3-acetic acid (IAA) production, ammonia and hydrogen cyanide (HCN) production, phosphate solubilization, etc. Furthermore, they were screened for in-vitro salt (NaCl) tolerance and Na+ uptake pattern, where two stress tolerant rhizobacteria B-1 and B-3 identified as Bacillus pumilus and Bacillus subtilis showed all PGPR traits with tolerance to salinity. These isolates also elicited significantly higher vigor index in tomato seedlings grown in pot culture experiments under saline sodic soils of pH 9.35 and EC 4.2. Key words: Rhizobacteria, salt tolerant, natural selection, PGPR.

Post Harvest Fruit Bioassay of Phylloplane, Pomoplane and Endophytic Microbes against Chilli Anthracnose Pathogen, Colletotrichum capsici (Syd.) E. J. Butler&bisby

Two hundred and fifty eight phylloplane/endophytic bacterial isolated from chilli leaves/fruits and one hundred pomoplane yeast isolates from vegetable/fruits were screened against Colletotrichum capsici by fruit bioassay (post harvest) method. Among the pomoplane bacterial isolates tested, Bacillus tequilensis (PMB-185) gave highest reduction (67.84%) of lesion development, where as among the phylloplane bacterial isolates, PHB-25 exhibited highest (48.65%) suppression of lesion caused by C. capsici. Among the endophytes tested, B. megaterium (ENB-86) produced the highest suppression of lesion (59.66%) and rhizospheric bacterium Pseudomonas putida (PBA-5) showed 50.68% suppression. Six bacteria exhibiting significant suppression (50.29 to 67.84%) were identified by 16s rDNA analysis and all of them belonged to Bacillus spp. including B. tequilensis (PMB-185), B. pumilus (PMB- 183), two B. subtilis (PMB-123 and ENB-24) and two B. megaterium (PMB-53 and ENB-86). Among the yeast isolates tested, the maximum reduction (72.16%) of lesion development was observed with the yeast isolate, Hanseniaspora uvarum (Y-73) which was the highest among all the antagonists tested. The results indicated that spraying of H. uvarum (Y-73) or B. tequilensis (PMB-185) on freshly harvested chilli fruits reduced post harvest fruit damage by C. capsici in chilli.

L-Glutamic acid production by Bacillus spp. isolated from vegetable proteins

22 isolates of Bacillus species were obtained from “Dawadawa”, “Ugba” and “Ogiri” (fermented vegetable proteins) in Nigeria. The isolates were identified as Bacillus subtilis (6), (27.3%), Bacillus pumilus (5), (22.7%), Bacillus licheniformis (5), (27.3%) and Bacillus polymyxa (6), (22.7%). Four species of the Bacillus isolates were selected based on their ability to grow and produce L- glutamic acid in a synthetic medium and their comparison with the reference strain Corynebacterium glutamicumATCC 13032. The four Bacillus species were B. subtilis (UGI). B. pumilus (DD4), B. licheniformis (0G4) and B. polymyxa (OG7) isolated from “Ugba”. “Dawadawa” and “Ogiri”, respectively. All the 22 Bacillus species isolated produced L- glutamic acid with B. subtilis (UGI) from “Ugba” recording the highest (8.5 mg/ml), while B. licheniformis (OG4) from “Ogiri” had the lowest value (5.0 mg/ml). L-Glutamic acid produced by B. subtilis (UGI) from “Ugba” (8.5 mg/ml) compared favourably with that produced by the reference strain C. glutamicum ATCC 13032, (10.2 mg/ml). All the isolates were able to utilize a range of carbon sources with glucose been the best, giving a yield of 8.4 mg/ml, while galactitol was least utilized. Ammonium nitrate was the best nitrogen source (6.5 mg/ml), while asparagine was least utilized (3.40 mg/ml) by the test isolates. Key words: L-Glutamic acid, bacteria strains, fermented vegetable proteins, fermentation.

Bacillus pumilus, a new pathogen on potato tubers in storage in Mali

Soft rot occurred severely in potato tubers stored in traditional and ameliored storehouses at Sikasso, Mali. 17 infective bacterial isolates were isolated from potato rot tissues (Solanum tuberosum L var. Odessa). Out of all, the isolate Od23 was found pathogenic and was characterized as rod-shaped, Gram positive, endo-spore formers and yellow pigment producers. This isolate which was found to be the principal organism responsible for potato rot in storage in Sikasso, grew at a temperature range from 5 to 45°C, with optimum temperature of 30 - 35°C. However, it showed strong pathogenicity to potato tubers at 30°C at 3 days. Furthermore, the 16S DNA analysis confirmed that the obtained isolate was Bacillus pumilus. All Potato varieties cultivated in Mali responded to infection with B. pumilus. Potato var. Sahel was the most susceptible, while Pamina appeared the most resistant potato variety from Mali. According to literature review, this is the first report on the occurrence of B. pumilus as a causal agent of potato soft rot in storage in the region of Sikasso, Mali. Key words: Potato, storage, Bacillus pumilus, soft rot, Mali.

Gas chromatography−Mass spectrometry analysis and antibacterial activity of essential oil from aerial parts and roots of Anisomeles indica Linn

The essential oil from the aerial part and roots of Anisomeles indica Linn. from the Toranmal forest, Maharashtra (India), was obtained by hydrodistillation after drying and grounding of the herbal material. A total of 27 components were resolved in the essential oil by GC-MS analysis, while 18 compounds were identified comparing the recorded mass spectra with the Nist 98/Nbs 75 K GC-MS library of mass spectra. The microbiological activity of the isolated essential oils was investigated as well. It was found that the essential oil shows microbiological activity on Escherichia coli, Pseudomonas aeruginosa, Bacillus pumilus and Staphylococcus aureus with a range of minimum inhibitory concentration values extended from 31.25 to 250 μg/ml. The percentage inhibition values calculated also support the minimum inhibitory concentration findings. The MBCs also performed for the same pathogens. Limonene, pinene, isobornyl acetate and eugenol can be considered as the main antimicrobial constituents in the essential oils of plants. Key words: Anisomeles indica Linn, essential oil, microbiological activity

Microbiological and physico-chemical properties of some commercial Nigerian honey

A total of 10 honey samples from different geographical locations of Nigeria were evaluated for their physico-chemical properties and microbiological quality. The honey samples were examined for antimicrobial activity against Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, Bacillus cereus, Proteus vulgaris, Pseudomonas aeruginosa, Salmonella spp, Shigella spp, Clostridium sporogenes and Candida albicans. The study revealed that the honeys had an average pH of 3.86, moisture content of 14.09%, ash content of 0.28% and electrical conductivity of 34.09 µS/cm. The free acidity was about 27.00 meq/kg, lactone acidity 10.55 meq/kg and total acidity of about 37.20 meq/kg. Results of the microbiological characteristics showed total coliform counts of 0 - 3.0 ◊ 10 cfu/g and total aerobic mesophilic bacteria (TAMB) between 1.0 ◊ 10 3 and 5.0 ◊ 10 3 cfu/g. Yeasts and moulds were not detected. The Bacillus species detected were identified as B. cereus, B. megaterium, B. polymyxa, B. licheniformis, B. firmus, and B. pumilus. The honey samples showed inhibitory activity at the various concentrations against Salmonella spp, Shigella spp, E. coli and Proteus vulgaris with the zones of inhibition increasing with honey concentration. B. cereus, K. pneumoniae and Clostridium sporogenes were inhibited at higher concentrations (50 - 100%) of the honey samples. The honey samples showed no inhibitory activity against S. aureus, P. aeruginosa and C. albicans.

Association of a Bacillus species with leaf and twig dieback of Asian pear (Pyrus pyrifolia) in China.

Leaf and twig dieback of Asian pear (Pyrus pyrifolia) was observed since 2006 in two orchards in Zhejiang Province (China). A gram positive bacterium was frequently isolated alone or in combination with Pseudomonas syringae pv. syringae from naturally infected twigs of field-grown pears. Inoculation of twigs with this bacterium resulted in the death of leaves and petioles as well as in twig dieback. The bacterium was identified as a Bacillus species (possibly Bacillus pumilus) by a polyphasic approach, including physiological and biochemical properties, carbon source utilization profile, fatty acid methyl esters and analysis of 16S rRNA gene sequence. This is the first report of the possible involvement of B. pumilus in leaf and twig dieback of Asian pear in China.

In vitro antibacterial activity of Artemisia annua Linn. growing in India.

The crude extracts obtained from the aerial parts of Artemisia annua Linn. (Asteraceae) were investigated for their antibacterial activity by using agar well diffusion assays against five Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis, Bacillus pumilus, Bacillus cereus, and Micrococcus luteus) and three Gram-negative bacteria (Escherichia coli, Salmonella typhi, and Pseudomonas aeruginosa). Of the various extracts, the methanol extract showed the strongest activity against most bacteria used in this study. The most sensitive organism to the extracts was M. luteus. The minimum inhibitory concentration (MIC) values were determined by the tube dilution method. The results showed that S. aureus required ~0.25 mg/mL of the methanol extract for inhibition. The HPTLC fingerprint of the methanol extract after derivatization with anisaldehyde sulphuric acid reagent showed a maximum number of separated components. TLC bioautography of the methanol extract showed that the area of inhibition around compounds differentiated at Rf = 0.32, Rf = 0.42, Rf = 0.46, Rf = 0.77, and Rf = 0.87 against S. aureus. This is the first report of the antibacterial activity of A. annua against food-borne bacteria. The results indicated that aerial parts of A. annua might be potential sources of new antibacterial agents. Key words: Antibacterial activity, Artemisia annua, MIC, TLC bioautography

Hydrolysis of β- d-xylo-oligosaccharides by β- d-xylosidase from Bacillus pumilus

Hydrolysis of β- d-xylo-oligosaccharides by β- d-xylosidase from Bacillus pumilus

Minor sesquiterpene lactones of Helianthus pumilus

The isolation of four known and two new germacradienolides and one known heliangolide from Helianthus pumilus, in addition to the previously report

Responses of Andropogon pumilus Roxb. to Various Heights and Intervals of Clipping

Responses of Andropogon pumilus Roxb. to Various Heights and Intervals of Clipping