Janibacter Sp Research Articles

Janibacter sp. Isolated from Deschampsia antarctica Rhizosphere as a Potential Source of Antimicrobial Compounds

Janibacter sp. Isolated from Deschampsia antarctica Rhizosphere as a Potential Source of Antimicrobial Compounds

Investigation on Metabolites in Structure and Biosynthesis from the Deep-Sea Sediment-Derived Actinomycete Janibacter sp. SCSIO 52865

For exploring structurally diverse metabolites and uniquely metabolic mechanisms, we systematically investigated the chemical constituents and putative biosynthesis of Janibacter sp. SCSIO 52865 derived from the deep-sea sediment based on the OSMAC strategy, molecular networking tool, in combination with bioinformatic analysis. As a result, one new diketopiperazine (1), along with seven known cyclodipeptides (2-8), trans-cinnamic acid (9), N-phenethylacetamide (10) and five fatty acids (11-15), was isolated from the ethyl acetate extract of SCSIO 52865. Their structures were elucidated by a combination of comprehensive spectroscopic analyses, Marfey's method and GC-MS analysis. Furthermore, the analysis of molecular networking revealed the presence of cyclodipeptides, and compound 1 was produced only under mBHI fermentation condition. Moreover, bioinformatic analysis suggested that compound 1 was closely related to four genes, namely jatA-D, encoding core non-ribosomal peptide synthetase and acetyltransferase.

Tomato plant growth promotion potential of Janibacter sp strain RC18

Actinomycetes are indispensable in the search for novel, potent and eco friendly fertilizers. The aim of this study was to investigate the ability of Janibacter sp. RC18 to enhance tomato plant growth. Janibacter sp. RC18 isolated from turmeric rhizosphere was screened for in vitro and in vivo plant growth promoting traits. The in vitro plant growth promotion traits exhibited by the strain were phosphate solubilization and ammonia production. The strain RC18 inoculated tomato plant recorded significant (P< 0.05) increase in plant height (45.67cm ± 1.5), number of leaves (69.67 ± 3.5), weight (19.40 g ± 0.53), and high soil phosphate solubilizing bacterial count (7.2x105 CFU/g) compared to the uninoculated control. High endogenous plant nutrient content N, P, K, (4.4%, 0.8 % and 1.1%) was also obtained with inoculation of Janibacter. Significant (p< 0.01) positive correlation was recorded with endogenous plant nutrient content and all the plant growth parameters except with the number of flowers. Findings from this study indicate that Janibacter sp RC18 is a good candidate for bio-inoculant formulation .

A novel thermophilic and halophilic esterase from Janibacter sp. R02, the first member of a new lipase family (Family XVII).

Janibacter sp. strain R02 (BNM 560) was isolated in our laboratory from an Antarctic soil sample. A remarkable trait of the strain was its high lipolytic activity, detected in Rhodamine-olive oil supplemented plates. Supernatants of Janibacter sp. R02 displayed superb activity on transesterification of acyl glycerols, thus being a good candidate for lipase prospection. Considering the lack of information concerning lipases of the genus Janibacter, we focused on the identification, cloning, expression and characterization of the extracellular lipases of this strain. By means of sequence alignment and clustering of consensus nucleotide sequences, a DNA fragment of 1272bp was amplified, cloned and expressed in E. coli. The resulting recombinant enzyme, named LipJ2, showed preference for short to medium chain-length substrates, and displayed maximum activity at 80°C and pH 8-9, being strongly activated by a mixture of Na+ and K+. The enzyme presented an outstanding stability regarding both pH and temperature. Bioinformatics analysis of the amino acid sequence of LipJ2 revealed the presence of a consensus catalytic triad and a canonical pentapeptide. However, two additional rare motifs were found in LipJ2: an SXXL β-lactamase motif and two putative Y-type oxyanion holes (YAP). Although some of the previous features could allow assigning LipJ2 to the bacterial lipase families VIII or X, the phylogenetic analysis showed that LipJ2 clusters apart from other members of known lipase families, indicating that the newly isolated Janibacter esterase LipJ2 would be the first characterized member of a new family of bacterial lipases.

A Novel Naturally Occurring Class I 5-Enolpyruvylshikimate-3-Phosphate Synthase from Janibacter sp. Confers High Glyphosate Tolerance to Rice.

As glyphosate is a broad spectrum herbicide extensively used in agriculture worldwide, identification of new aroA genes with high level of glyphosate tolerance is essential for the development and breeding of transgenic glyphosate-tolerant crops. In this study, an aroA gene was cloned from a Janibacter sp. strain isolated from marine sediment (designated as aroAJ. sp). The purified aroAJ. sp enzyme has a Km value of 30 μM for PEP and 83 μM for S3P, and a significantly higher Ki value for glyphosate (373 μM) than aroAE. coli. AroAJ. sp is characterized as a novel and naturally occurring class I aroA enzyme with glyphosate tolerance. Furthermore, we show that aroAJ. sp can be used as an effective selectable marker in both japonica and indica rice cultivar. Transgenic rice lines were tested by herbicide bioassay and it was confirmed that they could tolerate up to 3360 g/ha glyphosate, a dosage four-fold that of the recommended agricultural application level. To our knowledge, it is the first report of a naturally occurring novel class I aroA gene which can be efficiently utilized to study and develop transgenic glyphosate-tolerant crops, and can facilitate a more economical and simplified weed control system.

Biochemical properties of a new cold-active mono- and diacylglycerol lipase from marine member Janibacter sp. strain HTCC2649.

Mono- and di-acylglycerol lipase has been applied to industrial usage in oil modification for its special substrate selectivity. Until now, the reported mono- and di-acylglycerol lipases from microorganism are limited, and there is no report on the mono- and di-acylglycerol lipase from bacteria. A predicted lipase (named MAJ1) from marine Janibacter sp. strain HTCC2649 was purified and biochemical characterized. MAJ1 was clustered in the family I.7 of esterase/lipase. The optimum activity of the purified MAJ1 occurred at pH 7.0 and 30 °C. The enzyme retained 50% of the optimum activity at 5 °C, indicating that MAJ1 is a cold-active lipase. The enzyme activity was stable in the presence of various metal ions, and inhibited in EDTA. MAJ1 was resistant to detergents. MAJ1 preferentially hydrolyzed mono- and di-acylglycerols, but did not show activity to triacylglycerols of camellia oil substrates. Further, MAJ1 is low homologous to that of the reported fungal diacylglycerol lipases, including Malassezia globosa lipase 1 (SMG1), Penicillium camembertii lipase U-150 (PCL), and Aspergillus oryzae lipase (AOL). Thus, we identified a novel cold-active bacterial lipase with a sn-1/3 preference towards mono- and di-acylglycerides for the first time. Moreover, it has the potential, in oil modification, for special substrate selectivity.

Genetic and physiological characterization of denitrifying bacteria from brackishwater shrimp culture ponds of India

Denitrifying bacteria in brackishwater shrimp culture pond sediments were isolated and characterized from a total of eight samples. Out of the 264 isolates obtained, only 108 (40.96%) were positive for nitrate reduction and only 14 (12.96%) were positive for both nitrate and nitrite reduction. These fourteen isolates have been characterized based on complete reduction of nitrate to gas, presence of denitrification genes (nirS, nirK and nosZ), reverse transcriptase PCR for nirS gene and quantification of nitrous oxide after blocking the nitrous oxide reductase with acetylene. Out of the 14 isolates, nine were identified as Marinobacter spp., and the others belonged to Shewanella sp., Aquamicrobium sp., Marinimicrobium sp., Microbulbifer sp. and Janibacter sp. None of the denitrification genes could be detected in two of the isolates (CDN1 and 12) that reduced both nitrate and nitrite. RT-PCR analysis of all the Marinobacter isolates showed that nirS gene expression is better under anoxic than under oxic conditions indicating their ability to adapt to varying dissolved oxygen concentration. Results revealed that all the Marinobacter isolates are capable of denitrification under oxic, oxygen tolerant and anoxic conditions and indicated that nirS gene containing bacteria of the order Alteromonadales are one of the predominant denitrifying bacteria in brackishwater shrimp culture ponds of India. The study highlights the significance of such brackishwater ecosystems as study sites for future investigations on distribution and diversity of denitrifying bacteria and their role in the nitrogen cycle.

Gene cluster and regulation system for 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (DDE) degradation in Janibacter sp. TYM3221

A DDE-degrading bacterium, Janibacter sp. TYM3221, is able to grow on biphenyl and degrades 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (DDE) via a meta-ring cleavage pathway. The bphAa gene, encoding a biphenyl dioxygenase large subunit, was previously demonstrated to be involved in the degradation of DDE in TYM3221. The bph gene cluster, containing orf2 and bphDAaAbAcAdBCST was cloned and characterized. Reverse transcription-PCR (RT-PCR) analysis indicated that these genes were transcribed as an operon. The real-time RT-PCR on orf2, bphAa, bphC, and bphS suggest the presence of the inducible orf2 promoter (orf2p) and constitutive bphAa promoter (bphAap). The TYM3221 bphST conducted biphenyl-dependent inducible activation plus constitutive basal activation of orf2p and constitutive activation of bphAap in a rhodococcal host strain, Rhodococcus erythropolis IAM1399, suggesting that expression of the TYM3221 bph operon depends on the bphST-coded two-component regulatory system. Both of these promoters were also induced by the bphS1T1 of a biphenyl degrader, Rhodococcus jostii RHA1, and contained the 24-bp consensus sequences of RHA1 bphS1T1-dependent promoters. The replacement of RHA1 bphS1 with TYM3221 bphS in combination with RHA1 bphT1 suggests that TYM3221 bphS is responsible for low inducible and high constitutive activation of orf2p in IAM1399 by the TYM3221 bphST-system. Expression of bphAaAbAcAdBC in IAM1399 resulted in the transformation of DDE to the meta-ring cleavage product via 2,3-hydroxylation, suggesting that these genes are involved in DDE degradation.

Isolation of a BTEX-degrading bacterium, Janibacter sp. SB2, from a sea-tidal flat and optimization of biodegradation conditions

An enrichment culture was established using seawater containing BTEX (benzene, toluene, ethylbenzene and xylene) compounds to isolate a BTEX-degrading bacterium from contaminated sea-tidal flat. The enriched microbial communities were characterized by 16S rRNA-based DGGE profiling, which indicated that a Janibacter species was dominant during the enrichment. Strain SB2, corresponding to the major band and able to degrade all BTEX compounds, was isolated and characterized. NH4Cl, NaH2PO4, cell mass and BTEX concentrations were used as independent variables to optimize the degradation of BTEX by strain SB2 in a tidal flat and a statistically significant (R(2)=0.8933, p<0.0001) quadratic polynomial mathematical model was suggested. For the initial concentration of 240 mg/L BTEX in a slurry system containing 3.0×10(7) cells/L, 45.5% BTEX removal was observed under the optimum condition of NH4Cl and NaH2PO4, while 32.2% BTEX removal was observed under the untreated condition of NH4Cl and NaH2PO4.

Characterization of the 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (DDE) degradation system in Janibacter sp. TYM3221

Bacterial degradation of 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (DDE) has been previously reported, however, its degradation enzyme system has not been characterized. In this study, a DDE-degrading bacterium, Janibacter sp. TYM3221, was isolated and characterized. Transformation of DDE was demonstrated by TYM3211 resting cells grown in LB in the presence and absence of biphenyl. Gas chromatography–mass spectrometry analysis revealed five metabolites of DDE containing a meta-ring cleavage product and 4-chlorobenzoic acid, suggesting that TYM3221 degrades DDE to 4-chlorobenzoic acid via a meta-ring cleavage product. A gene cluster, bphAaAbAcAd, which codes for biphenyl dioxygenase subunits, was cloned from TYM3221. A mutant strain with a bphAa-gene inactivation did not grow on biphenyl, and showed no DDE degradation activity. These results indicate that in strain TYM3221, the bphAa-coded biphenyl dioxygenase is involved not only in the metabolism of biphenyl but also in the degradation of DDE.

Degradation of Mono-chlorinated Dibenzo-p-Dioxins by Janibacter sp. Strain YA Isolated from River Sediment

Strain YA was newly isolated from an enrichment culture of river sediment and was identified as Janibacter sp. It was able to utilize dibenzofuran as the sole source of carbon and energy. Strain YA degraded > 90% of 1-chloro-dibenzo-p-dioxin (1-CDD) and > 80% of 2-chloro-dibenzo-p-dioxin in 18 hours with each initial concentration at 40 mg/L. A novel metabolite, 2-chloro-2',6-dihydroxydiphenylether, was observed in 1-CDD degradation. From the metabolites detected by gas chromatography-mass spectrometry, strain YA was supposed to have at least two types of oxidation pathways in 1-CDD degradation.

Biotransformation of fluorene, diphenyl ether, dibenzo-p-dioxin and carbazole by Janibacter sp.

Fluorene, diphenyl ether, dibenzo-p-dioxin, and carbazole were used by a dibenzofuran-utilizing Janibacter sp. strain YY-1. Metabolites were identified by GC-MS. Angular dioxygenation was the major pathway for degradation of fluorene, diphenyl ether, and dibenzo-p-dioxin but not for carbazole. Lateral dioxygenation of all tested compounds was indicated by the detection of mono- or di-hydroxylated compounds. The bacterium also catalyzed the monooxygenation of fluorene at the C9 position.

Study of the biodegradation process of polychlorinated biphenyls in liquid medium and soil by a new isolated aerobic bacterium ( Janibacter sp.)

We have isolated and characterised a novel aerobic bacterial strain, designated MS3-02, belonging to the genus Janibacter sp. The capability of this new strain to degrade polychlorinated biphenyls (PCBs) in a commercial mixture (Aroclor 1242) in liquid medium and in soil (sterile and non sterile soil), under laboratory scale, has been evaluated. MS3-02 was isolated from the soil around of an incinerator, located in the east of Madrid (Spain). Gas-chromatographic analysis showed that MS3-02 was able to reduce most peaks observed in the chromatogram between 70% and 100% after seven days of incubation in a culture mineral medium containing yeast extract, but without the addition of biphenyl. The presence of biphenyl in the culture medium decreased the rate of PCB degradation by this bacterium. Comparing the performance of the MS3-02 in liquid culture medium and in soil, degradation was less efficient in sterile soil and still less efficient in non sterile soil. Under the best conditions (sterile soil and 20 weeks of incubation) MS3-02 was able to reduce, between 50% and 100%, nine of the main gas-chromatographic peaks in Aroclor 1242.