Caulobacter Sp Research Articles

Efficient synthesis of vanillylamine through bioamination of lignin-derived vanillin by recombinant E. coli containing ω-transaminase from Caulobacter sp. D5 in dimethyl sulfoxide-water

Lignin is a plentiful and readily accessible renewable resource. Vanillylamine is a crucial raw material used to synthesize pharmaceuticals and high-value furan compounds that can be acquired by aminating lignin-derived vanillin (Van). However, effectually achieving the biocatalytic synthesis of vanillylamine has remained challenging. In this study, a dimethyl sulfoxide (DMSO)-H2O (1:9, vol/vol) bioreaction medium was constructed, and a recombinant E. coli ATA1012 carrying ω-transaminase from Caulobacter sp. D5 was used as the ω-transaminase biocatalyst to acquire the effectual biocatalytic synthesis of vanillylamine. Under optimized bioreaction conditions (37 ℃ and pH 7.5) by supplementary of isopropylamine (IPA) (Van/IPA = 1:5, mol/mol), 80–100 mM Van could be effectually converted by ATA1012 whole cells in DMSO-H2O (1:9, vol/vol) within 12 h, yielding 91.2 %–95.4 % vanillylamine, with >99 % selectivity. An efficient amination process was developed using ATA1012 with superior transaminase catalytic activity and substrate tolerance to effectively convert Van to vanillylamine in a DMSO-H2O medium.

Complete Genome Sequence of Caulobacter sp. Strain S6, Obtained Using Oxford Nanopore and Illumina Sequencing.

ABSTRACTWe report the complete genome sequence of Caulobacter sp. strain S6, generated from Oxford Nanopore and Illumina sequencing. The assembled genome comprises a chromosome with a length of 5.5 Mb and a plasmid of 96,014 bp.

Mitigation of Nickel Toxicity and Growth Promotion in Sesame through the Application of a Bacterial Endophyte and Zeolite in Nickel Contaminated Soil.

Nickel (Ni) bioavailable fraction in the soil is of utmost importance because of its involvement in plant growth and environmental feedbacks. High concentrations of Ni in the soil environment, especially in the root zone, may retard plant growth that ultimately results in reduced plant biomass and yield. However, endophytic microorganisms have great potential to reduce the toxicity of Ni, especially when applied together with zeolite. The present research work was conducted to evaluate the potential effects of an endophytic bacterium Caulobacter sp. MN13 in combination with zeolite on the physiology, growth, quality, and yield of sesame plant under normal and Ni stressed soil conditions through possible reduction of Ni uptake. Surface sterilized sesame seeds were sown in pots filled with artificially Ni contaminated soil amended with zeolite. Results revealed that plant agronomic attributes such as shoot root dry weight, total number of pods, and 1000-grains weight were increased by 41, 45, 54, and 65%, respectively, over control treatment, with combined application of bacteria and zeolite in Ni contaminated soil. In comparison to control, the gaseous exchange parameters (CO2 assimilation rate, transpiration rate, stomatal- sub-stomatal conductance, chlorophyll content, and vapor pressure) were significantly enhanced by co-application of bacteria and zeolite ranging from 20 to 49% under Ni stress. Moreover, the combined utilization of bacteria and zeolite considerably improved water relations of sesame plant, in terms of relative water content (RWC) and relative membrane permeability (RMP) along with improvement in biochemical components (protein, ash, crude fiber, fat), and micronutrients in normal as well as in Ni contaminated soil. Moreover, the same treatment modulated the Ni-stress in plants through improvement in antioxidant enzymes (AEs) activities along with improved Ni concentration in the soil and different plant tissues. Correlation and principal component analysis (PCA) further revealed that combined application of metal-tolerant bacterium Caulobacter sp. MN13 and zeolite is the most influential strategy in alleviating Ni-induced stress and subsequent improvement in growth, yield, and physio-biochemical attributes of sesame plant.

Conformational Analysis of the Mannosidase Inhibitor Kifunensine: A Quantum Mechanical and Structural Approach.

The varied yet family-specific conformational pathways used by individual glycoside hydrolases (GHs) offer a tantalising prospect for the design of tightly binding and specific enzyme inhibitors. A cardinal example of a GH-family-specific inhibitor, and one that finds widespread practical use, is the natural product kifunensine, which is a low-nanomolar inhibitor that is selective for GH family 47 inverting α-mannosidases. Here we show, through quantum-mechanical approaches, that kifunensine is restrained to a "ring-flipped" 1 C4 conformation with another accessible, but higher-energy, region around the 1,4 B conformation. The conformations of kifunensine in complex with a range of GH47 enzymes-including an atomic-level resolution (1 Å) structure of kifunensine with Caulobacter sp. CkGH47 reported herein and with GH family 38 and 92 α-mannosidases-were mapped onto the kifunensine free-energy landscape. These studies revealed that kifunensine has the ability to mimic the product state of GH47 enzymes but cannot mimic any conformational states relevant to the reaction coordinate of mannosidases from other families.

Pyrene metabolism by the novel bacterial strains Burkholderia fungorum (T3A13001) and Caulobacter sp (T2A12002) isolated from an oil-polluted site in the Arabian Gulf

The novel bacterial strains Burkholderia fungorum T3A13001 and Caulobacter sp T2A12002, which were previously isolated from oil-contaminated sites and identified via 16S RNA sequences, were tested for their hydrocarbon degrading efficiency. Media spiked with 100 ppm pyrene were incubated at 25 °C and 37 °C. The bacterial isolates' pyrene-degrading capability was assessed in acidic (pH 5.0) and alkaline (pH 9.0) media. Caulobacter sp degraded 21% and 24% of the pyrene at pH 9.0 and 5.0, respectively; thus, the strain was more active at pH 5.0 than pH 9.0. B. fungorum was active in a wide range of pH values, because it biodegraded 59%–62% of the provided pyrene in acidic and alkaline media. Caulobacter sp degraded 35%–36% of the provided pyrene in cultures at 37 °C and 25 °C. B. fungorum degraded 56% and 59% of the provided pyrene at 37 °C and 25 °C, respectively. Given that B. fungorum biodegraded over the half-life of the initial 100 ppm pyrene in the cultures, the strain may be suitable for bioremediation of high molecular weight PAHs. The study provides important insight into possible PAH biodegradation and bioremediation of hydrocarbon-polluted sites using novel bacterial strains.

The long-term effect of uranium and pH on the community composition of an artificial consortium.

In the environment, microorganisms are living in diverse communities, which are impacted by the prevailing environmental conditions. Here, we present a study investigating the effect of low pH and elevated uranium concentration on the dynamics of an artificial microbial consortium. The members (Caulobacter sp. OR37, Asinibacterium sp. OR53, Ralstonia sp. OR214 and Rhodanobacter sp. OR444) were isolated from a uranium contaminated and acidic subsurface sediment. In pure culture, Ralstonia sp. OR214 had the highest growth rate at neutral and low pH and only Caulobacter sp. OR37 and Asinibacterium sp. OR53 grew in the presence uranium. The four strains were mixed in equal ratios, incubated at neutral and low pH and in the presence uranium and transferred to fresh medium once per week for 30 weeks. After 30 weeks, Ralstonia sp. OR214 was dominant at low and neutral pH and Caulobacter sp. OR37 and Asinibacterium sp. OR53 were dominant in the presence of uranium. After 12 weeks, the cultures were also transferred to new conditions to access the response of the consortia to changing conditions. The transfers showed an irreversible effect of uranium, but not of low pH on the consortia. Overall, the strains initially tolerant to the respective conditions persisted over time in high abundances in the consortia.

Cellulose degradation by one mesophilic strain Caulobacter sp. FMC1 under both aerobic and anaerobic conditions

Caulobacteria are presumed to be responsible for considerable mineralization of organic material in aquatic environments. In this study, a facultative, mesophilic and cellulolytic bacterium Caulobacter sp. FMC1 was isolated from sediments which were taken from a shallow freshwater lake and then enriched with amendment of submerged macrophyte for three months. This strain seemed to evolve a capacity to adapt redox-fluctuating environments, and could degrade cellulose both aerobically and anaerobically. Cellulose degradation percentages under aerobic and anaerobic conditions were approximately 27% and 10% after a 240-h incubation in liquid mediums containing 0.5% cellulose, respectively. Either cellulose or cellobiose alone was able to induce activities of endoglucanase, exoglucanase, and β-1,4-glucosidase. Interestingly, ethanol was produced as the main fermentative product under anaerobic incubation on cellulose. These results could improve our understanding about cellulose-degrading process in aquatic environments, and were also useful in optimizing cellulose bioconversion process for bioethanol production.

The limitations of draft assemblies for understanding prokaryotic adaptation and evolution

The de novo assembly of next generation sequencing data is a daunting task made more difficult by the presence of genomic repeats or transposable elements, resulting in an increasing number of genomes designated as completed draft assemblies. We created and assembled idealized sequence data sets for Cupriavidus metallidurans CH34, Caulobacter sp. K31, Gramella forsetii KT0803, Rhodobacter sphaeroides 2.4.1 and Bordetella bronchiseptica RB50. In addition to confirming the role of transposable elements in interrupting the assemblies, an association was found between the most fragmented regions and known or predicted genomic islands in these strains. Assembly quality was more strongly related to putative genomic island content than to any other factor examined. We believe this association indicates that draft assemblies are limiting our ability to understand the genomic context of important bacterial adaptations and that the increased effort required for finishing genomes can provide a wealth of information for future studies.

A psychrotolerant Caulobacter sp. from Russian polar tundra soil

Strain Z-0024, a psychrotolerant aerobic heterotrophic representative of the prosthecate bacteria of the genus Caulobacter, was isolated from a methanotrophic enrichment obtained from Russian polar tundra soil. The cells of the new isolate are vibrios (0.5-0.6 x 1.3-1.8 microm) with a polar stalk. The organism grows in a temperature range from 5 to 36 degrees C, with an optimum at 20 degrees C. The pH range for growth is from 4.5 to 7.0 with an optimum at pH 6.0. Strain Z-0024 utilizes a wide range of organic compounds: sugars, amino acids, volatile fatty acids, and primary alcohols. It tolerates a NaCl concentration in the medium of up to 15 g/l. The G + C content of DNA is 66.6 mol %. The 16S rRNA gene sequence analysis revealed that strain Z-0024 belongs to the cluster of Caulobacter species, showing a 98.8-99.2% sequence similarity to them. DNA-DNA hybridization revealed a low level of homology (24%) between strain Z-0024 and C. vibrioides ATCC 15252. The new isolate is described as Caulobacter sp. Z-0024.