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Applied and Environmental Microbiology Jul 1990Alcaligenes latus, Alcaligenes eutrophus, Bacillus cereus, Pseudomonas pseudoflava, Pseudomonas cepacia, and Micrococcus halodenitrificans were found to accumulate...
Alcaligenes latus, Alcaligenes eutrophus, Bacillus cereus, Pseudomonas pseudoflava, Pseudomonas cepacia, and Micrococcus halodenitrificans were found to accumulate poly-(beta-hydroxybutyric-co-beta-hydroxyvaleric) acid [P(HB-co-HV)] copolymer when supplied with glucose (or sucrose in the case of A. latus) and propionic acid under nitrogen-limited conditions. A fed-batch culture of A. eutrophus produced 24 g of poly-beta-hydroxybutyric acid (PHB) liter-1 under ammonium limitation conditions. When the glucose feed was replaced with glucose and propionic acid during the polymer accumulation phase, 17 g of P(HB-co-HV) liter-1 was produced. The P(HB-co-HV) contained 5.0 mol% beta-hydroxyvaleric acid (HV). Varying the carbon-to-nitrogen ratio at a dilution rate of 0.15 h-1 in a chemostat culture of A. eutrophus resulted in a maximum value of 33% (wt/wt) PHB in the biomass. In comparison, A. latus accumulated about 40% (wt/wt) PHB in chemostat culture under nitrogen-limited conditions at the same dilution rate. When propionic acid was added to the first stage of a two-stage chemostat, A. latus produced 43% (wt/wt) P(HB-co-HV) containing 18.5 mol% HV. In the second stage, the P(HB-co-HV) increased to 58% (wt/wt) with an HV content of 11 mol% without further addition of carbon substrate. The HV composition in P(HB-co-HV) was controlled by regulating the concentration of propionic acid in the feed. Poly-beta-hydroxyalkanoates containing a higher percentage of HV were produced when pentanoic acid replaced propionic acid.
Topics: Alcaligenes; Bacillus cereus; Bacteria; Micrococcus; Pentanoic Acids; Polyesters; Propionates; Pseudomonas
PubMed: 2117877
DOI: 10.1128/aem.56.7.2093-2098.1990 -
3 Biotech Nov 2020This study aimed to investigate the antimicrobial, antibiofilm, and cytotoxic effects of biosurfactant lipopeptides synthesized by TR47II. For this purpose, the...
This study aimed to investigate the antimicrobial, antibiofilm, and cytotoxic effects of biosurfactant lipopeptides synthesized by TR47II. For this purpose, the lipopeptides were partially purified using a three-step process and characterized. In the first step, the crude extract obtained from acid precipitation exhibited strong antibacterial activity against the Gram-negative opportunistic pathogens ATCC 8750, ATCC 13138, ATCC 14909, and ATCC 15175. Moreover, partial inhibition was observed against ATCC 13048 (42%), ATCC 25922 (16%), and ATCC 27853 (47%). The lipopeptides in the crude extract were extracted with methanol and fractioned on a silica gel chromatography column, rendering four TLC-pooled chromatographic fractions, named F1, F2, F3, and F4. The chromatographic fraction F4 was the most bioactive, with MIC values between 300 and 600 µg mL. Besides, F4 at sub-MIC doses dislodged the biofilms of , , and by about 100, 85, and 81%, respectively. No cytotoxic effect was observed in mammalian cells at MIC. MALDI-TOF-MS analysis revealed that F4 contained cyclic lipopeptides belonging to two families: iturins (m/z 1004 to 1087) and fengycins (m/z 1424 to 1545). The dual effect of F4 on planktonic and sessile growth could suggest that the synergistic application of these biosurfactants could be efficient in the control of these opportunistic pathogens.
PubMed: 33072469
DOI: 10.1007/s13205-020-02459-z -
Microbiology and Molecular Biology... Mar 1999Poly(3-hydroxyalkanoates) (PHAs) are a class of microbially produced polyesters that have potential applications as conventional plastics, specifically thermoplastic... (Review)
Review
Poly(3-hydroxyalkanoates) (PHAs) are a class of microbially produced polyesters that have potential applications as conventional plastics, specifically thermoplastic elastomers. A wealth of biological diversity in PHA formation exists, with at least 100 different PHA constituents and at least five different dedicated PHA biosynthetic pathways. This diversity, in combination with classical microbial physiology and modern molecular biology, has now opened up this area for genetic and metabolic engineering to develop optimal PHA-producing organisms. Commercial processes for PHA production were initially developed by W. R. Grace in the 1960s and later developed by Imperial Chemical Industries, Ltd., in the United Kingdom in the 1970s and 1980s. Since the early 1990s, Metabolix Inc. and Monsanto have been the driving forces behind the commercial exploitation of PHA polymers in the United States. The gram-negative bacterium Ralstonia eutropha, formerly known as Alcaligenes eutrophus, has generally been used as the production organism of choice, and intracellular accumulation of PHA of over 90% of the cell dry weight have been reported. The advent of molecular biological techniques and a developing environmental awareness initiated a renewed scientific interest in PHAs, and the biosynthetic machinery for PHA metabolism has been studied in great detail over the last two decades. Because the structure and monomeric composition of PHAs determine the applications for each type of polymer, a variety of polymers have been synthesized by cofeeding of various substrates or by metabolic engineering of the production organism. Classical microbiology and modern molecular bacterial physiology have been brought together to decipher the intricacies of PHA metabolism both for production purposes and for the unraveling of the natural role of PHAs. This review provides an overview of the different PHA biosynthetic systems and their genetic background, followed by a detailed summation of how this natural diversity is being used to develop commercially attractive, recombinant processes for the large-scale production of PHAs.
Topics: Acetyl-CoA C-Acetyltransferase; Acyltransferases; Alcohol Oxidoreductases; Amino Acid Sequence; Bacterial Proteins; Biodegradation, Environmental; Cupriavidus necator; DNA, Bacterial; Industrial Microbiology; Molecular Sequence Data; Oxidation-Reduction; Polyesters; Pseudomonas; Recombination, Genetic; Rhizobium; Sequence Homology
PubMed: 10066830
DOI: 10.1128/MMBR.63.1.21-53.1999 -
Frontiers in Microbiology 2023Genus is a large assemblage of diverse microorganisms, not sharing a common evolutionary history. To clarify their evolutionary relationships and classification, we...
Genus is a large assemblage of diverse microorganisms, not sharing a common evolutionary history. To clarify their evolutionary relationships and classification, we have conducted comprehensive phylogenomic and comparative analyses on 388 genomes. In phylogenomic trees, species formed 12 main clusters, apart from the "Aeruginosa clade" containing its type species, . In parallel, our detailed analyses on protein sequences from genomes have identified 98 novel conserved signature indels (CSIs), which are uniquely shared by the species from different observed clades/groups. Six CSIs, which are exclusively shared by species from the "Aeruginosa clade," provide reliable demarcation of this clade corresponding to the genus in molecular terms. The remaining 92 identified CSIs are specific for nine other species clades and the genera and which branch in between them. The identified CSIs provide strong independent evidence of the genetic cohesiveness of these species clades and offer reliable means for their demarcation/circumscription. Based on the robust phylogenetic and molecular evidence presented here supporting the distinctness of the observed species clades, we are proposing the transfer of species from the following clades into the indicated novel genera: Alcaligenes clade - gen. nov.; Fluvialis clade - gen. nov.; Linyingensis clade - gen. nov.; Oleovorans clade - gen. nov.; Resinovorans clade - gen. nov.; Straminea clade - gen. nov.; and Thermotolerans clade - gen. nov. In addition, descriptions of the genera , , , and are emended to include information for the CSIs specific for them. The results presented here should aid in the development of a more reliable classification scheme for species.
PubMed: 38249459
DOI: 10.3389/fmicb.2023.1273665 -
Frontiers in Microbiology 2021High concentrations of Y12 significantly inhibit the development of housefly larvae and accelerate larvae death. In this study, the dynamic distribution of the gut...
High concentrations of Y12 significantly inhibit the development of housefly larvae and accelerate larvae death. In this study, the dynamic distribution of the gut microbiota of housefly larvae fed different concentrations of Y12 was investigated. Compared with low-concentration diets, orally administered high-concentration diets caused higher mortality and had a greater impact on the community structure and interaction network of intestinal flora in housefly larvae. The bacterial community of the gut microbiota in housefly larvae was reconstructed in 4 days. Bacterial abundance and diversity were significantly reduced in housefly larvae fed high concentrations of . With the growth of larvae, the relative abundances of , , , , and increased significantly in housefly larvae fed with high concentrations of , while the relative abundances of , , , , , and were significantly reduced. To analyze the role of the gut microorganisms played on housefly development, a total of 10 cultivable bacterial species belonging to 9 genera were isolated from the intestine of housefly larvae among which , , , , and promoted the growth of larvae through feeding experiments. This study is the first to analyze the influence of high concentrations of on the gut microbiota of houseflies. Our study provides a basis for exploring the pathogenic mechanism of high concentrations of Y12 in houseflies.
PubMed: 34335517
DOI: 10.3389/fmicb.2021.691158 -
Journal of Bacteriology Sep 1989The 163-kilobase-pair (kb) plasmid pMOL28, which determines inducible resistance to nickel, cobalt, chromate, and mercury salts in its native host Alcaligenes eutrophus...
The 163-kilobase-pair (kb) plasmid pMOL28, which determines inducible resistance to nickel, cobalt, chromate, and mercury salts in its native host Alcaligenes eutrophus CH34, was transferred to a derivative of A. eutrophus H16 and subjected to cloning procedures. After Tn5 transposon mutagenesis, restriction endonuclease analysis, and DNA-DNA hybridization, two DNA fragments, a 9.5-kb KpnI fragment and a 13.5-kb HindIII fragment (HKI), were isolated. HKI contained EK1, the KpnI fragment, as a subfragment flanked on both sides by short regions. Both fragments were ligated into the suicide vector pSUP202, the broad-host-range vector pVK101, and pUC19. Both fragments restored a nickel-sensitive Tn5 mutant to full nickel and cobalt resistance. The hybrid plasmid pVK101::HKI expressed full nickel resistance in all nickel-sensitive derivatives, either pMOL28-deficient or -defective, of the native host CH34. The hybrid plasmid pVK101::HKI also conferred nickel and cobalt resistance to A. eutrophus strains H16 and JMP222, Alcaligenes hydrogenophilus, Pseudomonas putida, and Pseudomonas oleovorans, but to a lower level of resistance. In all transconjugants the metal resistances coded by pVK101::HKI were expressed constitutively rather than inducibly. The hybrid plasmid metal resistance was not expressed in Escherichia coli. DNA sequences responsible for nickel resistance in newly isolated strains showed homology to the cloned pMOL28-encoded nickel and cobalt resistance determinant.
Topics: Alcaligenes; Blotting, Southern; Cloning, Molecular; Conjugation, Genetic; DNA Transposable Elements; Genes, Bacterial; Metals; Mutation; Nickel; Nucleic Acid Hybridization; Pseudomonas; R Factors; Restriction Mapping
PubMed: 2549012
DOI: 10.1128/jb.171.9.5071-5078.1989 -
Saudi Pharmaceutical Journal : SPJ :... Feb 2017A series of esters of 4-acetyl, 4-trifluoroacetyl- and 4-(3-chloropropionyl)aminobenzenethiosulfoacids (twenty-four compounds) were synthesized and characterized by...
A series of esters of 4-acetyl, 4-trifluoroacetyl- and 4-(3-chloropropionyl)aminobenzenethiosulfoacids (twenty-four compounds) were synthesized and characterized by elemental analysis, H NMR and IR spectroscopy. The antibacterial activity of the novel candidates has been screened using the agar diffusion or serial dilution methods against representative Gram-positive (, , , sp., ), Gram-negative ( sp., , , , , ) bacteria and fungi (, , , , , , , ). Particular potency has been discovered against all tested pathogenic bacteria and fungi by compounds and at nanomolar concentrations. Some appropriate effect of thiosulfoesters structure upon their antimicrobial activity was determined.
PubMed: 28344478
DOI: 10.1016/j.jsps.2016.06.007 -
3 Biotech Sep 2022Chasmophytes are a group of diverse plants growing on cracks and crevices of rocks. They survive under nutrient and water-limited conditions. Microorganisms associated...
UNLABELLED
Chasmophytes are a group of diverse plants growing on cracks and crevices of rocks. They survive under nutrient and water-limited conditions. Microorganisms associated with chasmophytes may play a critical role in their survival. In the present study, 263 bacterial isolates were obtained from chasmophytic wild collected from Tsomoriri, Ladakh. Members of , , and comprised ~ 90% of the Gram-negative bacteria, while among Gram-positive, and were most abundant. When evaluated for various plant growth-promoting traits, 36 bacteria could solubilize insoluble phosphate, 10 bacteria could release potassium from silicate minerals, and 25 bacteria could solubilize ZnO, while 124 bacteria produced siderophores. ACC deaminase activity was present in 31 isolates, while 46 bacteria could produce IAA (10.40-232.0 μg/mL). Furthermore, more than 64% of the isolates could grow at 50 °C, while ~ 60% could grow at 4 °C. Similarly, ~ 50% isolates were able to grow with > 1.7 M NaCl and ~ 70% could grow under high osmolarity (~ 67 mOsmol/L). The ability of these microorganisms to grow under such a wide range of temperature, salinity, and osmolarity offers adaptive advantage to colonize plants surviving under harsh environmental conditions. A large number (30-49%) of these isolates could produce acids from various sugars and sugar alcohols which is crucial to release mineral nutrients trapped in the rocks. The results indicated that genetically and functionally diverse microflora associated with wild might be helping these plants to effectively mine nutrients and water under extreme conditions.
SUPPLEMENTARY INFORMATION
The online version contains supplementary material available at 10.1007/s13205-022-03278-0.
PubMed: 36032512
DOI: 10.1007/s13205-022-03278-0 -
Indoor Air Jan 2018The flushing of toilets generates contaminated aerosols, the transmission of which may cause the spread of disease, particularly in the immunocompromised or the elderly....
The flushing of toilets generates contaminated aerosols, the transmission of which may cause the spread of disease, particularly in the immunocompromised or the elderly. This study investigated the emission strength of three types of airborne bacteria, namely Staphylococcus epidermidis, Escherichia coli, and Pseudomonas alcaligenes, during toilet flushing in a custom-built toilet under a controlled environment. Flushing was activated by a flushometer operated at two pressure levels, 400 kPa (high pressure [HP]) and 200 kPa (low pressure [LP]), and by a water cistern tank placed 95 cm (high tank [HT]) and 46 cm (low tank [LT]) above the toilet seat. The pathogens emitted by the first flush were calculated, with the correlations between airborne pathogen emissions and droplet concentration (HP, r=0.944, P<.001; LP, r=0.803, P<.001, HT, r=0.885, P<.05) and bacterial size (HP, r=-0.919, P<.001; LP, r=-0.936, P<.001; HT, r=-0.967, P<.05) in the different conditions then tested. The emission strength in the HP condition was statistically greater than that in the LP condition, whereas the cistern tank system produced less emissions than the flushometer system, and tank height was not found to be a sensitive parameter.
Topics: Aerosols; Air Microbiology; Toilet Facilities
PubMed: 28683156
DOI: 10.1111/ina.12406 -
Heliyon Dec 2017The isolation of microorganisms from soil impacted by xenobiotic chemicals and exposing them in the laboratory to the contaminant can provide important information about...
The isolation of microorganisms from soil impacted by xenobiotic chemicals and exposing them in the laboratory to the contaminant can provide important information about their response to the contaminants. The purpose of this study was to isolate bacteria from soil with historical application of herbicides and to evaluate their potential to degrade diuron. The isolation media contained either glucose or diuron as carbon source. A total of 400 bacteria were isolated, with 68% being Gram-positive and 32% Gram-negative. Most isolates showed potential to degrade between 10 and 30% diuron after five days of cultivation; however TD4.7 and TD4.31 were able to degrade 87% and 68%, respectively. The degradation of diuron resulted in the formation of the metabolites DCPMU, DCPU, DCA, 3,4-CAC, 4-CA, 4-CAC and aniline. Based on these results it was proposed that TD2.3, TD4.7, TD4.31 and TG 4.48, act on 3,4-DCA and 4-CA by alkylation and dealkylation while and sp follow dehalogenation directly to aniline. Growth on aniline as sole carbon source demonstrates the capacity of strains to open the aromatic ring. In conclusion, the results show that the role of microorganisms in the degradation of xenobiotics in the environment depends on their own metabolism and also on their synergistic interactions.
PubMed: 29322098
DOI: 10.1016/j.heliyon.2017.e00471