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Frontiers in Bioengineering and... 2021Dextran has aroused increasingly more attention as the primary pollutant in sucrose production and storage. Although enzymatic hydrolysis is more efficient and...
Dextran has aroused increasingly more attention as the primary pollutant in sucrose production and storage. Although enzymatic hydrolysis is more efficient and environmentally friendly than physical methods, the utilization of dextranase in the sugar industry is restricted by the mismatch of reaction conditions and heterogeneity of hydrolysis products. In this research, a dextranase from G6-4B was purified and characterized. Through anion exchange chromatography, dextranase was successfully purified up to 32.25-fold with a specific activity of 288.62 U/mg protein and a Mw of 71.12 kDa. The optimum reaction conditions were 55°C and pH 7.5, and it remained relatively stable in the range of pH 7.0-9.0 and below 60°C, while significantly inhibited by metal ions, such as Ni, Cu, Zn, Fe, and Co. Noteworthily, a distinction of previous studies was that the hydrolysates of dextran were basically isomalto-triose (more than 73%) without glucose, and the type of hydrolysates tended to be relatively stable in 30 min; dextranase activity showed a great influence on hydrolysate. In conclusion, given the superior thermal stability and simplicity of hydrolysates, the dextranase in this study presented great potential in the sugar industry to remove dextran and obtain isomalto-triose.
PubMed: 35223821
DOI: 10.3389/fbioe.2021.813079 -
PloS One 2021Despite the formation of biofilms on catheters for extracorporeal membrane oxygenation (ECMO), some patients do not show bacteremia. To elucidate the specific linkage...
Despite the formation of biofilms on catheters for extracorporeal membrane oxygenation (ECMO), some patients do not show bacteremia. To elucidate the specific linkage between biofilms and bacteremia in patients with ECMO, an improved understanding of the microbial community within catheter biofilms is necessary. Hence, we aimed to evaluate the biofilm microbiome of ECMO catheters from adults with (n = 6) and without (n = 15) bacteremia. The microbiomes of the catheter biofilms were evaluated by profiling the V3 and V4 regions of bacterial 16s rRNA genes using the Illumina MiSeq sequencing platform. In total, 2,548,172 reads, with an average of 121,341 reads per sample, were generated. Although alpha diversity was slightly higher in the non-bacteremic group, the difference was not statistically significant. In addition, there was no difference in beta diversity between the two groups. We found 367 different genera, of which 8 were present in all samples regardless of group; Limnohabitans, Flavobacterium, Delftia, Massilia, Bacillus, Candidatus, Xiphinematobacter, and CL0-1 showed an abundance of more than 1% in the sample. In particular, Arthrobacter, SMB53, Neisseria, Ortrobactrum, Candidatus Rhabdochlamydia, Deefgae, Dyella, Paracoccus, and Pedobacter were highly abundant in the bacteremic group. Network analysis indicated that the microbiome of the bacteremic group was more complex than that of the non-bacteremic group. Flavobacterium and CL0.1, which were abundant in the bacteremic group, were considered important genera because they connected different subnetworks. Biofilm characteristics in ECMO catheters varied according to the presence or absence of bacteremia. There were no significant differences in diversity between the two groups, but there were significant differences in the community composition of the biofilms. The biofilm-associated community was dynamic, with the bacteremic group showing very complex network connections within the microbiome.
Topics: Arthrobacter; Bacteremia; Bacteria; Biofilms; Catheter-Related Infections; Extracorporeal Membrane Oxygenation; Female; Humans; Male; Microbiota; Middle Aged; Neisseria; RNA, Ribosomal, 16S; Retrospective Studies
PubMed: 34529734
DOI: 10.1371/journal.pone.0257449 -
Journal of Applied Microbiology Sep 2019Study is focused on the influence of cadmium addition to growth media on production yield, their size and molecular mass of exopolysaccharides (EPS) synthesized by three...
AIM
Study is focused on the influence of cadmium addition to growth media on production yield, their size and molecular mass of exopolysaccharides (EPS) synthesized by three rhizosphere bacteria strains. Inhibition of bacterial growth by increasing concentrations of Cd was also analysed.
METHODS AND RESULTS
The highest impact of Cd was noticed on the growth of Arthrobacter sp. and Rhizobium metallidurans. Chryseobacterium sp. and Arthrobacter sp. produced significantly lower when compared to R. metallidurans amounts of EPS under the influence of Cd . In all bacterial strains both size and molecular mass decreased after addition of Cd to growth media. It causes a change in EPS conformation to more planar, which minimizes the volume of liquid in the interglobular space next to the bacterial wall. Results confirmed strong effect of Cd on the structure and synthesis of bacterial EPS what can be a key factor in the interactions between rhizosphere bacteria and host plants in heavy metal polluted soils.
CONCLUSION
This work proves that due to the presence of cadmium ions, the size and conformation of EPS produced by selected bacterial strains is changed to minimize their impact on cell. We suggest that shifting in EPS conformation from bigger globular particles to the smaller planar ones could be one of the probable mechanisms of Cd resistance in metallotolerant bacteria, and finally explain increased efficiency of heavy metal phytoextraction by EPS-producing plant growth-promoting micro-organisms.
SIGNIFICANCE AND IMPACT OF THE STUDY
One of the most promising remediation technique for Cd-contaminated areas is the phytoremediation in which rhizosphere bacteria play an important role by protecting plants' roots from toxic condition thus enhancing efficiency of intake. EPS secretion by bacteria is one of the most common mechanisms to protect the cell from impact of unpleasant environmental conditions, for example, toxicity of heavy metals like Cd.
Topics: Arthrobacter; Bacteria; Biodegradation, Environmental; Cadmium; Flavobacteriaceae; Polysaccharides, Bacterial; Rhizobium; Rhizosphere; Soil Pollutants
PubMed: 31211899
DOI: 10.1111/jam.14354 -
International Journal of Systematic and... Jun 2019A Gram-stain-positive, aerobic and rod-shaped bacterial strain, designated JH1-1, was isolated from a forest soil sample collected in Suwon, Gyeonggi-do, Republic of...
A Gram-stain-positive, aerobic and rod-shaped bacterial strain, designated JH1-1, was isolated from a forest soil sample collected in Suwon, Gyeonggi-do, Republic of Korea. Strain JH1-1 could grow at 10-35 °C (optimum, 28-30 °C), pH 4.5-8.5 and tolerated 5 % (w/v) NaCl. Strain JH1-1 was most closely related to members of the genus , namely LC6 (98.5 % similarity), TGA (98.4 %), CCM 1646 (97.8 %), THG-GM18 (97.5 %) and P3B162 (97.3 %). The strain grew well on Reasoner's 2A agar, tryptone soya agar, nutrient agar, Mueller-Hinton agar and Luria-Bertani agar. The major polar lipid profile comprised phosphatidylglycerol, diphosphatidylglycerol, unidentified phospholipid and unidentified glycolipids. The major respiratory quinone was MK-9(H). The main fatty acids were C anteiso, C iso, C iso and C anteiso. The DNA G+C content of the isolated strain based on the whole genome sequence was 63.6 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain JH1-1 and its reference type strains ranged from 81.3 to 85.4 % and from 21.1 to 29.1 %, respectively. Based on phenotypic, chemotypic and genotypic evidence, strain JH1-1 could be differentiated phylogenetically and phenotypically from the recognized species of the genus . Therefore, strain JH1-1 is considered to represent a novel species, for which the name sp. nov. is proposed. The type strain is JH1-1 (=KACC 21385=JCM 33641).
PubMed: 33555248
DOI: 10.1099/ijsem.0.004686 -
International Journal of Systematic and... May 2020A pink-coloured bacterium (strain KR32) was isolated from cheese and assigned to the ' group'. Members of the 'pink group' form a stable clade (100 % bootstrap value)...
A pink-coloured bacterium (strain KR32) was isolated from cheese and assigned to the ' group'. Members of the 'pink group' form a stable clade (100 % bootstrap value) and contain the species , and , which share ≥99.0 % 16S rRNA gene sequence similarity. Isolate KR32 showed highest 16S rRNA gene sequence similarity (99.9 %) to DSM 20550. Additional multilocus sequence comparison confirmed the assignment of strain KR32 to the clade 'pink group'. Average nucleotide identity and digital DNA-DNA hybridization values between isolate KR32 and DSM 20550 were 82.85 and 26.30 %, respectively. The G+C content of the genomic DNA of isolate KR32 was 69.14 mol%. Chemotaxonomic analysis determined anteiso-C as the predominant fatty acid and MK-9(H) as the predominant menaquinone. Polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and monoacyldimannosyl-monoacylglycerol. The peptidoglycan type of the isolate was A3α. The carotenoid bacterioruberin was detected as the major pigment. At 10 °C, strain KR32 grew with increased concentrations of bacterioruberin and production of unsaturated fatty acids. Strain KR32 was a Gram-stain-positive, catalase-positive, oxidase-positive and coccus-shaped bacterium with optimal growth at 27-30 °C and pH 8. The results of phylogenetic and phenotypic analyses enabled the differentiation of the isolate from other closely related species of the 'pink group'. Therefore, strain KR32 represents a novel species for which the name sp. nov. is proposed. The type strain is KR32 (=DSM 109896=LMG 31480=NCCB 100733).
Topics: Animals; Arthrobacter; Bacterial Typing Techniques; Base Composition; Cattle; Cell Wall; Cheese; DNA, Bacterial; Fatty Acids; Female; Food Microbiology; Germany; Glycolipids; Milk; Nucleic Acid Hybridization; Peptidoglycan; Phospholipids; Phylogeny; Pigmentation; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Vitamin K 2
PubMed: 32223834
DOI: 10.1099/ijsem.0.004125 -
Microbiology Resource Announcements Oct 2022Arthrobacter phage Iter was isolated in North Georgia. Its genome is 43,963 bp with 70 open reading frames (ORFs) and a GC content of 67.4%. It shares 89.11%...
Arthrobacter phage Iter was isolated in North Georgia. Its genome is 43,963 bp with 70 open reading frames (ORFs) and a GC content of 67.4%. It shares 89.11% nucleotide identity with phage Phives. Actinobacteriophages that share over 50% nucleotide identity are sorted into clusters, with Iter in cluster AZ.
PubMed: 36066250
DOI: 10.1128/mra.00538-22 -
BMC Microbiology Aug 2021In unfavourable environment, such as nutrient limitation, some bacteria encased themselves into a three dimensional polymer matrix called biofilm. The majority of...
BACKGROUND
In unfavourable environment, such as nutrient limitation, some bacteria encased themselves into a three dimensional polymer matrix called biofilm. The majority of microbial infections in human are biofilm related, including chronic lung, wound, and ear infections. The matrix of biofilm which consists of extracellular polymeric substances (EPS) causes bacterial colonization on medical implanted device in patients, such as catheter and lead to patient's death. Biofilm infections are harder to treat due to increasing antibiotic resistance compared to planktonic microbial cells and escalating the antibiotic concentration may result into in vivo toxicity for the patients. Special compounds which are non-microbicidal that could inhibit or destroy biofilm formation are called antibiofilm compounds, for example enzymes, anti-quorum sensing, and anti-adhesins. Arthrobacter sp. CW01 produced antibiofilm compound known as amylase. This time our preliminary study proved that the antibiofilm compound was not only amylase, but also protease. Therefore, this research aimed to optimize the production of antibiofilm agents using amylase and protease inducing media. The five types of production media used in this research were brain heart infusion (BHI) (Oxoid), BHI with starch (BHIS), casein with starch (CS), yeast extract with starch (YS), and casein-yeast extract with starch (CYS). Biofilm eradication and inhibition activities were assayed against Pseudomonas aeruginosa (ATCC 27,853) and Staphylococcus aureus (ATCC 25,923).
RESULTS
The results showed that different production media influenced the antibiofilm activity. Addition of starch, casein and yeast extract increased the production of amylase and protease significantly. Higher amylase activity would gradually increase the antibiofilm activity until it reached the certain optimum point. It was shown that crude extracts which contained amylase only (BHI, BHIS and YS) had the optimum eradication activity against P. aeruginosa and S. aureus biofilm around 60-70 %. Meanwhile, CS and CYS crude extracts which contained both amylase and protease increased the biofilm eradication activity against both pathogens, which were around 70-90 %.
CONCLUSIONS
It was concluded that the combination of amylase and protease was more effective as antibiofilm agents against P. aeruginosa and S. aureus rather than amylase only.
Topics: Amylases; Anti-Bacterial Agents; Arthrobacter; Biofilms; Caseins; Culture Media; Humans; Microbial Sensitivity Tests; Peptide Hydrolases; Pseudomonas aeruginosa; Staphylococcus aureus; Starch; Yeasts
PubMed: 34425755
DOI: 10.1186/s12866-021-02294-z -
Current Microbiology Jul 2023A study was undertaken to determine the effects of a strain of Arthrobacter sp., a Plant Growth-Promoting Bacteria (PGPB), on plant phenology and qualitative composition...
A study was undertaken to determine the effects of a strain of Arthrobacter sp., a Plant Growth-Promoting Bacteria (PGPB), on plant phenology and qualitative composition of Opuntia ficus-indica (L.) Mill. fruits and cladodes. The strain was inoculated in soil, and its effects on cactus pear plants were detected and compared to nontreated plants. Compared to the latter, the treatment with bacteria promoted an earlier plant sprouting (2 months before the control) and fruitification, ameliorating fruit quality (i.e., improved fresh and dry weight: + 24% and + 26%, respectively, increased total solid content by 30% and polyphenols concentrations by 22%). The quality and quantity of monosaccharides of cladodes were also increased by Arthrobacter sp. with a positive effect on their nutraceutical value. In summer, the mean values of xylose, arabinose, and mannose were significantly higher in treated compared to not treated plants (+ 3.54; + 7.04; + 4.76 mg/kg d.w. respectively). A similar trend was observed in autumn, when the cladodes of inoculated plants had higher contents, i.e., 33% xylose, 65% arabinose, and 40% mannose, respect to the controls. In conclusion, Arthrobacter sp. plays a role in the improvement of nutritional and nutraceutical properties of cactus pear plants due to its capabilities to promote plant growth. Therefore, these results open new perspectives in PGPB application in the agro-farming system as alternative strategy to improve cactus pear growth, yield, and cladodes quality, being the latter the main by-product to be utilized for additional industrial uses.
Topics: Fruit; Opuntia; Arthrobacter; Mannose; Arabinose; Xylose; Dietary Supplements
PubMed: 37400738
DOI: 10.1007/s00284-023-03368-z -
FEMS Microbiology Ecology Aug 2022Algal-bacterial interactions provide clues to algal physiology, but mutualistic interactions are complicated by dynamic exchange. We characterized the response of...
Algal-bacterial interactions provide clues to algal physiology, but mutualistic interactions are complicated by dynamic exchange. We characterized the response of Chlamydomonas reinhardtii to the presence of a putative alga-benefitting commensal bacterium (Arthrobacter strain 'P2b'). Co-cultivation promoted chlorophyll content, biomass, average cell size, and number of dividing cells, relative to axenic cultures. Addition of bacterial spent medium (whole, size-fractionated and heat-treated) had similar effects, indicating P2b does not require algal interaction to promote growth. Nutrients and pH were excluded as putative effectors, collectively indicating a commensal interaction mediated by Arthrobacter-released small exometabolite(s). Proteogenomic comparison revealed similar response to co-cultivation and spent media, including differential cell cycle regulation, extensive downregulation of flagellar genes and histones, carbonic anhydrase and RubisCO downregulation, upregulation of some chlorophyll, amino acid and carbohydrate biosynthesis genes, and changes to redox and Fe homeostasis. Further, Arthrobacter protein expression indicated some highly expressed putative secondary metabolites. Together, these results revealed that low molecular weight bacterial metabolites can elicit major physiological changes in algal cell cycle regulation, perhaps through a more productive G1 phase, that lead to substantial increases in photosynthetically-produced biomass. This work illustrates that model commensal interactions can be used to shed light on algal response to stimulating bacteria.
Topics: Bacteria; Cell Cycle; Chlamydomonas; Chlamydomonas reinhardtii; Chlorophyll
PubMed: 35977399
DOI: 10.1093/femsec/fiac091 -
International Journal of... 2023The PAH degrading microbial consortium was collected from sodic soil of the nursery of Guru Jambheshwar University of Science and Technology, Hisar, Haryana (India). And...
The PAH degrading microbial consortium was collected from sodic soil of the nursery of Guru Jambheshwar University of Science and Technology, Hisar, Haryana (India). And the soil was artificially amended with phenanthrene and naphthalene to isolate the PAHs degrading microbial consortium. The diversity of microbial consortium was analyzed using the NGS (Next Generation Sequencing) based metagenomic approach. The result of diversity analysis showed species were present in the consortium. Moreover, Sphingomonas, Arthrobacter, Sphingobium, Azospirillium, Thirohodococcus, and Pelotomaculum were the prominent pollutant degrader genera in the microbial consortium. Since the bioremediation of these pollutants occurs with a significant reduction in toxicity, the study's perspective is to use this type of consortium for bioremediation of specifically contaminated soil.
Topics: Biodegradation, Environmental; Soil; Polycyclic Aromatic Hydrocarbons; Microbiota; Microbial Consortia; Soil Pollutants; Soil Microbiology
PubMed: 36694290
DOI: 10.1080/15226514.2023.2170321