Stenotrophomonas Pavanii Research Articles

Arsenic efflux in Enterobacter cloacae RSN3 isolated from arsenic-rich soil.

In the present study, bacterial isolates were screened for arsenic resistance efficiency. Environmental isolates were isolated from arsenic-rich soil samples (i.e., from Rajnandgaon district of Chhattisgarh state, India). Amplification and sequencing of 16S rRNA gene revealed that the isolates were of Bacillus firmus RSN1, Brevibacterium senegalense RSN2, Enterobacter cloacae RSN3, Stenotrophomonas pavanii RSN6, Achromobacter mucicolens RSN7, and Ochrobactrum intermedium RSN10. Arsenite efflux gene (arsB) was successfully amplified in E. cloacae RSN3. Atomic absorption spectroscopy (AAS) analysis showed an absorption of 32.22% arsenic by the RSN3 strain. Furthermore, results of scanning electron microscopy (SEM) for morphological variations revealed an initial increase in the cell size at 1 mM sodium arsenate; however, it was decreased at 10 mM concentration in comparison to control. This change of the cell size in different metal concentrations was due to the uptake and expulsion of the metal from the cell, which also confirmed the arsenite efflux system.

Efecto de bacterias emulsificantes en la atenuación de la fitotoxicidad de suelos contaminados con petróleo intemperizado

Introduction: Plants and microorganisms have been used as bioindicators to evaluate the toxicity of hydrocarbons in soils. Objective: This study evaluates the toxicity of a chronically-contaminated Gleysol with several concentrations of weathered petroleum hydrocarbons (WPH), collected from La Venta, Tabasco (Mexico), on the growth of Clitoria ternatea and the phytoxicity attenuation due to inoculation of emulsifying bacteria. Methods: Soils with 50 and 150 g WPH kg-1, and control soil with 0.15 g WPH kg-1 (biogenic origin) were utilized, as well as the inoculation of six emulsifying bacteria and their combination (consortium). The WPH-phytotoxicity was evaluated by considering plant height, dry biomass production (root, shoot, and total), leaf area, specific leaf area, and the efficiency of photosystem II (EPSII), after 30 days. Results: WPH did not affect plant height, but soil with 50 g WPH kg-1 diminished root and total dry weight, and leaf area, when compared to both control soil and soil with 150 g WPH kg-1. The strain Sml (Stenotrophomonas maltophilia C10S1) significantly increased shoot and total dry weight, while the strain Ro (Raoultella ornithinolytica C5S3) produced higher specific leaf area relative to uninoculated plants. In control soil, the bacterial consortium stimulated plant height. The strains Sm (Serratia marcescens C11S1) and Sm2 (S. marcescens C7S3) improved plant height and specific leaf area when compared to uninoculated plants in soil with 50 g WPH kg-1. In soil with 150 g WPH kg-1, strains Spa (Stenotrophomonas pavanii C5S3F) and Cfr (Citrobacter freundii C4S3) enhanced root and shoot dry weight, respectively. The EPSII was unaffected by soil contamination. Emulsifying bacteria reduced the phytotoxic effects of WP, but depending on the content of WPH in soils. Conclusions: Soil with 50 g WPH kg-1 showed the greatest phytotoxic effects on plant growth. Bacterial inoculation favored growth, biomass production and leaf area in soil with 150 g WPH kg-1. The EPSII was not affected by WPH in soils.

Endophytic Bacteria Associated with Medicinal Plant Vernonia anthelmintica: Diversity and Characterization.

Increasing evidence shows that endophytic bacteria living inside plant tissue may possess similar biological activity and produce similar metabolites to their hosts. This study aimed to determine the diversity of endophytic bacteria associated with Vernonia anthelmintica and to evaluate their biological activity. The bacteria were isolated from the plant tissue using culture-dependent techniques. Comparison of the 16S rRNA gene sequences of endophytic bacteria isolated from V. anthelmintica showed that isolates belong to the species Micrococcus endophyticus VERA1, Bacillus megaterium VERA2, Pseudomonas chlororaphis VERA3, P. kilonensis VERA4, Stenotrophomonas pavanii VERA5, B. endophyticus VERA6, S. maltophilia VERA7, Pantoea ananatis VERA8, B. atrophaeus VERA9 and M. flavus VERA10. Activity studies showed that the endophytic bacteria share several similar biological properties with their host plant including antimicrobial, anti-vitiligo and antidiabetic activities. These findings indicate that plant phytochemical compounds and activity play an important role in the physiological properties of their endophytes.

Evaluation of Different Salts and Heavy Metal Concentrations on Bacterial Biofilm from Selected Surface and Borehole Water Samples

Biofilms in drinking water systems can serve as significant environmental reservoirs for pathogenic bacteria associated with gastro-enteric diseases. The evaluation of the effects of different salts and metal concentrations on bacterial biofilm from surface and borehole water samples was conducted. Water samples were collected, from 10 selected water sources of economic importance, aseptically using sterile containers. The physicochemical properties were investigated before the biofilm generation process. The collected water samples were allowed to stand in a secluded environment for four (4) weeks at 27°C±2°C for biofilm generation. The isolates were characterized culturally, morphologically, biochemically and molecularly. The isolates were identified as Stenotrophomonas pavanii, Stenotrophomonas maltophilia, Chromobacterium violaceum, Bacillus cereus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa. It was observed that the isolates exhibited growth at a wide range of temperature, salts, pH, and metal salt concentrations. To determine the metal tolerance of the isolates, different concentrations (0.05, 0.1, 0.5, and 1.0%) of four metal salts; ferrous chloride (FeCl2), zinc chloride (ZnCl2), calcium chloride (CaCl2), and magnesium oxide (MgO) was used in nutrient broth. Their ability to grow in medium containing different salt (NaCl) concentrations was also evaluated. Different concentrations of NaCl ranging from 2.0% to 10.0% were used in nutrient broth seeded with 0.1ml of the inocula and incubated at 37°C for 48 and 24hours respectively. Growth was measured in terms of OD at 660 nm using spectrophotometer. Results showed a decline in the growth of the isolates with percentage increase in concentrations of all the metal salts. The result of the effect of NaCl salt on growth showed a decrease in growth with an increase in NaCl concentration from 2% to 10%. For Stenotrophomonas pavanii, FeCl2 is negatively correlated with pH r=-.998 but there is positive correlation between CaCl2 and NaCl with r=889.

Characterization and potential of plant growth-promoting rhizobacteria on rice seedling growth and the effect on Xanthomonas oryzae pv. oryzae

Abstract. Rahma H, Nurbailis, Kristina N. 2019. Characterization and potential of plant growth-promoting rhizobacteria on rice seedling growth and the effect on Xanthomonas oryzae pv. oryzae. Biodiversitas 20: 3654-3661. Xanthomonas oryzae pv. oryzae (Xoo), a major limiting factor in rice production, and the use of resistant Xoo varieties have failed to control the bacterial pathogens as well as increased yield. It is due to the diversity in pathotypes, caused by environmental factors, the nature of resistant variety used, and gene mutation. The aims of this study were to select rhizobacterial strains with the potential of suppressing Xoo growth and promoting the growth of rice seedlings. This experiment was conducted in a completely randomized design (CRD) using seven rhizobacterial isolates selected through a dual culture test, with four replications. There were four isolates that potential in inhibiting the growth of Xoo, namely KJKB5.4, LMTSA5.4, Bacillus cereus AJ34, and Alcaligenes faecalis AJ14, with inhibition diameters greater than 11.50 mm. Rhizobacterial supernatant of 4 potential isolates has a zone of inhibition ranging from 12.25 to 24.00 mm. Four potential isolates were also able to solubilize phosphate, produce indole acetic acid (IAA) growth hormone, and siderophore, as well as enhance the growth of rice seedlings. Based on the nucleic acid sequencing of LMTSA5.4, KJKB5.4, and RK12 isolates were identified as Stenotrophomonas malthopilia strain LMG 958 (99.13%) accession NR 119220.1, Stenotrophomonas pavanii strain LMG 25348 (95.84%) accession NR 118008.1 and Ochrobactrum ciceri strain ca-34 (92.91%) accession NR115819.1.

Prospects of Stenotrophomonas pavanii DB1 in diesel utilization and reduction of its phytotoxicity on Vigna radiata

Diesel, for its carcinogenic and teratogenic properties, is considered as an environmental hazard. The present study concentrates on diesel utilization by Stenotrophomonas pavanii DB1 under various physicochemical parameters and mass spectral analysis of the metabolites produced. Soil remediation potential of the culture for reducing diesel toxicity against Vigna radiata seed germination was also evaluated. Supplementation of the broth with ammonium sulfate, molasses and tween 80 enhanced diesel utilization (up to 66.3%). A steady decrease in diesel utilization (69.46–51.23%) was recorded with the increase in salinity from 1 to 5000 mM. Similarly, the utilization efficiency was low (up to 11.5%) when cadmium, lead and mercury salts were present but was not affected by zinc and copper salts. Liquid chromatography–mass spectrometry revealed extensive utilization (95–99%) of both the short- (C10–C20) and long-chain (C18–C30) n-alkanes. Significantly, the culture exhibited uniform utilization of various recalcitrant n-alkanes, to generate metabolites like aldehyde, ketone, fatty acids, carboxylic and dicarboxylic acids. Stenotrophomonas pavanii DB1 mediated 95% and 86% of diesel utilization in soil with and without nutrient amendment, respectively. Germination percentage of V. radiata seeds improved with the bacterial inoculation of the diesel-containing soil. Stenotrophomonas pavanii DB1 culture did not establish antagonistic effect over the resident soil bacteria. Based on the spectral analysis and soil remediation studies, it could be inferred that S. pavanii DB1 is a potential culture for bioremediation of sites polluted with diesel.

Combining amplicon sequencing and metabolomics in cirrhotic patients highlights distinctive microbiota features involved in bacterial translocation, systemic inflammation and hepatic encephalopathy

In liver cirrhosis (LC), impaired intestinal functions lead to dysbiosis and possible bacterial translocation (BT). Bacteria or their byproducts within the bloodstream can thus play a role in systemic inflammation and hepatic encephalopathy (HE). We combined 16S sequencing, NMR metabolomics and network analysis to describe the interrelationships of members of the microbiota in LC biopsies, faeces, peripheral/portal blood and faecal metabolites with clinical parameters. LC faeces and biopsies showed marked dysbiosis with a heightened proportion of Enterobacteriaceae. Our approach showed impaired faecal bacterial metabolism of short-chain fatty acids (SCFAs) and carbon/methane sources in LC, along with an enhanced stress-related response. Sixteen species, mainly belonging to the Proteobacteria phylum, were shared between LC peripheral and portal blood and were functionally linked to iron metabolism. Faecal Enterobacteriaceae and trimethylamine were positively correlated with blood proinflammatory cytokines, while Ruminococcaceae and SCFAs played a protective role. Within the peripheral blood and faeces, certain species (Stenotrophomonas pavanii, Methylobacterium extorquens) and metabolites (methanol, threonine) were positively related to HE. Cirrhotic patients thus harbour a ‘functional dysbiosis’ in the faeces and peripheral/portal blood, with specific keystone species and metabolites related to clinical markers of systemic inflammation and HE.

Isolation and role of polylactic acid-degrading bacteria on degrading enzymes productions and PLA biodegradability at mesophilic conditions

Enumeration and isolation of polylactic acid (PLA)-degrading bacteria from soils and wastewater sludge were performed on emulsified PLA agar. Two isolates of potent PLA-degrading bacteria, designated as CH1 and WS3, were selected and identified as Stenotrophomonas pavanii and Pseudomonas geniculata, respectively. PLA was presented as a substrate to stimulate production of protease and PLA-degrading enzyme by S. pavanii CH1 and P. geniculata WS3. The optimal pH values for both protease and PLA-degrading enzyme production by S. pavanii CH1 and P. geniculata WS3 were 7.5 and 8.0, respectively. The optimal gelatin concentrations for stimulating protease production in S. pavanii CH1 and P. geniculata WS3 were 0.3% (w/v), while those for PLA-degrading enzyme production in S. pavanii CH1 and P. geniculata WS3 were 0.1 and 0.3% (w/v), respectively. In addition, P. geniculata WS3 had a higher percentage of PLA film-weight loss than that of S. pavanii CH1, corresponding with reduced molecular weight of PLA. A significant increase of lactic acid content in culture broth was directly correlated with the increasing percentage of PLA film-weight loss. Our results clearly demonstrated that P. geniculata WS3, a novel isolated bacterium, has played a substantial role in PLA biodegradation by producing PLA-degrading enzyme and adhering on PLA surface.

Soft rot disease alters soil characteristics and root-associated, culturable microbial community of Amorphophallus konjac

To elucidate how soft rot disease affects soil characteristics and root-associated, culturable microorganisms in Amorphophallus konjac stands, the responses of soil around roots of A. konjac with soft rot disease were investigated in stands with and without soft rot. Changes in the root-associated culturable microbial community and diversity were investigated by dilution plating. Soil characteristics were compared between stands using standard techniques. A. konjac with soft rot had higher concentrations of available soil P and K, NH4–N, organic matter and water content and lower pH compared with plants without. The community composition of root-associated culturable microorganisms differed between stands with and without soft rot. The microbial community associated with soft rot in A. konjac was characterized by four types of abundant microorganisms (Fusarium solani, Fusarium oxysporum, Pseudomonas chlororaphis subsp. aureofaciens and Stenotrophomonas pavanii) and three types of less-abundant microorganisms (Rhizobium radiobacter, Bacillus thuringiensis and Streptomyces cellulosae), and a small number of Bacillus and Streptomyces species in the rhizosphere and rhizoplane soils. Particular microbial combinations were diametrically opposed between plants with and without soft rot. The richness and diversity of root-associated culturable microorganisms were higher in the stand without soft rot than in the stand with soft rot. A. konjac soft rot led to obvious differences in the diversity and community composition of root-associated culturable microorganisms and in soil characteristics.

Nitrogen fixation, plant growth and yield enhancements by diazotrophic growth-promoting bacteria in two cultivars of chickpea ( Cicer arietinum L.)

A total of 11 rhizobia-like-bacteria, isolated from the nodules of chickpea, were characterized for nitrogen fixation potential and growth promoting ability. All the isolates nodulated chickpea, amplified nifH gene and fixed nitrogen but, four isolates (ICKM-9, ICKM-15, ICS-31 and ICS-32) were found to fix nitrogen more than 4.0 nmoles of ethylene g−1 fresh weight of nodules h−1. Under field conditions, seeds of chickpea varieties ICCV 2 and JG 11, when treated with the bacteria, enhanced the nodule number (up to 46% and 46%), nodule mass (up to 76% and 50%), shoot mass (up to 21% and 42%) and grain yield (up to 27% and 25%), respectively, over the un-inoculated control. At the harvest, organic carbon (up to 7% and 24%), total nitrogen (up to 11% and 19%) and available phosphorous (up to 14% and 29%) were found enhanced, respectively, in the rhizosphere of ICCV-2 and JG-11 treated with bacteria over the un-inoculated control. All the isolates produced plant growth-promoting traits including indole acetic acid, β-1,3-glucanase, hydro cyanic acid (except ICKM-17 and ICS-31) and siderophore (except ICS-31). The 16 S rDNA gene sequences of bacterial isolates of ICKM-1, ICKM-4, ICKM-7, ICKM-9, ICKM-12, ICKM-14, ICKM-15, ICKM-17, ICS-30, ICS-31 and ICS-32 showed maximum identity with Pantoea dispersa, Chryseobacterium indologenes, Pseudomonas geniculata, Stenotrophomonas pavanii, P. geniculata, P. geniculata, Stenotrophomonas maltophilia, Chryseobacterium sp., P. geniculata, Chryseobacterium indologenes and Stenotrophomonas acidaminiphila, respectively. This study indicates nodule-associated bacteria could be a valuable pool for improving nitrogen fixation and crop yields in chickpea.

Enhanced degradation of chlorpyrifos in rice (Oryza sativa L.) by five strains of endophytic bacteria and their plant growth promotional ability

Endophytic bacteria reside in plant tissues, such as roots, stems, leaves and seeds. Most of them can stimulate plant growth or alleviate phytotoxicity of pollutants. There are handful species with dual functions stimulating plant growth and degrading pollutants have been reported. Five endophytic bacteria were isolated from chlorpyrifos (CP) treated rice plants and identified as Pseudomonas aeruginosa strain RRA, Bacillus megaterium strain RRB, Sphingobacterium siyangensis strain RSA, Stenotrophomonas pavanii strain RSB and Curtobacterium plantarum strain RSC according to morphological characteristics, physiological and biochemical tests, and 16S rDNA phylogeny. All of them possessed some plant growth promotional traits, including indole acetic acid and siderophore production, secretion of phosphate solubilization and 1-aminocyclopropane-1-carboxylate deaminase. The bacteria were marked with the green fluorescent protein (gfp) gene and successfully colonized into rice plants. All isolates were able to degrade CP in vitro and in vivo. The five isolates degraded more than 90% of CP in 24 h when the initial concentration was lower than 5 mg/L. CP degradation was significantly enhanced in the infested rice plants and rice grains. The final CP residual was reduced up to 80% in the infested rice grains compared to the controls. The results indicate that these isolates are promising bio-inoculants for the removal or detoxification of CP residues in rice plants and grains.

Biodegradation of low density polyethylene (LDPE) modified with dye sensitized titania and starch blend using Stenotrophomonas pavanii

Plastic goods including plastic shopping bags, which are generally made from low density polyethylene (LDPE), are a cause of considerable environmental nuisance. Development of a material that would degrade, due to simple factors i.e. sunlight and/or biotic factors, in the open environment, is therefore, of considerable interest. Biodegradation of photodegraded and non-photodegraded LDPE films, modified with food grade dye sensitized titania (TiO2) nanoparticles and starch blend, was evaluated under laboratory conditions. Bacterial strains were isolated from solid waste dump site using enrichment culture and two step screening procedure for their ability to degrade LDPE. Bacterial strains capable of growing in the LDPE-Titania environment were further screened for their ability to form biofilm on LDPE films, salt aggregation test (SAT) and cell surface hydrophobicity. The potential bacterial strains were then identified as Pseudomonas aeruginosa (CA9), Burkholderia seminalis (CB12), and Stenotrophomonas pavanii (CC18) (GenBank accession number KR738718, KR738720 and KR738722, respectively) based on the 16S rRNA gene sequence homology. The strain CC18 showed highest biofilm, hydrophobicity and growth rate. The LDPE films of 3 × 3 cm were incubated with CC18 in mineral salt media (MSM) for 56 days. The viability tests of the isolates grown on LDPE surface were performed which also correlated with the protein density of biomass (R2 = 0.98). LDPE films were characterized using SEM, TGA, XRD and FTIR before and after incubation. Biodegradation of LDPE was confirmed by an increase in the Keto Carbonyl, Ester Carbonyl and Vinyl Bond Index compared to control. The results conclusively demonstrated the potential of the LDPE-titania-starch blend for production of shopping bags which may easily be degraded in open environment after use.

Stenotrophomonas tumulicola sp. nov., a major contaminant of the stone chamber interior in the Takamatsuzuka Tumulus.

During investigation of the biological contamination of the 1300-year-old mural paintings and plaster walls inside the stone chambers of the Takamatsuzuka and Kitora Tumuli (TT and KT) in Asuka-mura, Nara Prefecture, Japan, the identity of 17 bacterial isolates from blackish mouldy spots and viscous gels (biofilms) collected from both tumuli (16 isolates from TT and one from KT) during our 2005-2007 microbiological survey was systematically elucidated. One cluster of the major bacterial isolates was assigned to the genus Stenotrophomonas (class Gammaproteobacteria) by phylogenetic analysis of the 16S rRNA gene sequences. These isolates were divided into two groups A and B. Group A comprised 15 TT isolates that took a phylogenetic position near Stenotrophomonas chelatiphaga LPM-5T. Based on our analysis of the phenotypic (cultural, morphological, physiological and chemotaxonomic) characteristics and genotypic/molecular characteristics (DNA base composition, DNA-DNA relatedness, and 16S rRNA and gyrB gene sequences), the novel species name Stenotrophomonas tumulicola sp. nov. is proposed for the group A isolates with the type strain T5916-2-1bT ( = JCM 30961T = NCIMB 15009T). Group B, which contained only one TT and one KT isolate, was closely related to [Pseudomonas] geniculata, [P.] hibiscicola, [P.] beteli, Stenotrophomonas maltophilia and Stenotrophomonas pavanii. The two isolates were genotypically and phenotypically assignable to S. maltophilia.