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Astrobiology Sep 2018It is well known that dissolved salts can significantly lower the freezing point of water and thus extend habitability to subzero conditions. However, most...
It is well known that dissolved salts can significantly lower the freezing point of water and thus extend habitability to subzero conditions. However, most investigations thus far have focused on sodium chloride as a solute. In this study, we report on the survivability of the bacterial strain Planococcus halocryophilus in sodium, magnesium, and calcium chloride or perchlorate solutions at temperatures ranging from +25°C to -30°C. In addition, we determined the survival rates of P. halocryophilus when subjected to multiple freeze/thaw cycles. We found that cells suspended in chloride-containing samples have markedly increased survival rates compared with those in perchlorate-containing samples. In both cases, the survival rates increase with lower temperatures; however, this effect is more pronounced in chloride-containing samples. Furthermore, we found that higher salt concentrations increase survival rates when cells are subjected to freeze/thaw cycles. Our findings have important implications not only for the habitability of cold environments on Earth but also for extraterrestrial environments such as that of Mars, where cold brines might exist in the subsurface and perhaps even appear temporarily at the surface such as at recurring slope lineae.
Topics: Chlorides; Cold Temperature; Freezing; Microbial Viability; Osmolar Concentration; Perchlorates; Planococcus Bacteria; Salts; Water
PubMed: 29664686
DOI: 10.1089/ast.2017.1805 -
International Journal of Systematic and... Dec 2018A Gram-stain-positive, rod-shaped bacterial strain, 22-7, was isolated from ocean sediment of Laizhou Bay, China, and was characterized by using a polyphasic approach....
A Gram-stain-positive, rod-shaped bacterial strain, 22-7, was isolated from ocean sediment of Laizhou Bay, China, and was characterized by using a polyphasic approach. Optimal growth was observed at 33 °C on a 2216E agar plate of pH 7.5 and with 2 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences identified it as a member of the genus Jeotgalibacillus, most similar to Jeotgalibacillus campisalis SF-57 (98.7 % similarity), Jeotgalibacillus marinus DSM 1297 (98.2 %) and Jeotgalibacillus soli P9 (97.1 %). Average nucleotide identity values and digital DNA-DNA hybridization values were less than 74.2 and 18.1 %, respectively, between strain 22-7 and the type strains of closely related species. The major polar lipids were aminophospholipid, phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol; the major fatty acids (>10 %) were anteiso-C15 : 0 and iso-C15 : 0; and the major menaquinone was MK-7. The peptidoglycan type of the cell wall was A1α linked through l-lysine as the diamino acid. Combined data from phenotypic, chemotaxonomic and genotypic characterizations demonstrated that strain 22-7 represents a novel Jeotgalibacillus species, for which the name Jeotgalibacillus proteolyticus sp. nov. is proposed. The type strain is 22-7(=MCCC 1H00228=KCTC 33930).
Topics: Bacterial Typing Techniques; Base Composition; Cell Wall; China; DNA, Bacterial; Fatty Acids; Geologic Sediments; Nucleic Acid Hybridization; Peptide Hydrolases; Peptidoglycan; Phospholipids; Phylogeny; Planococcaceae; RNA, Ribosomal, 16S; Seawater; Sequence Analysis, DNA; Vitamin K 2
PubMed: 30328805
DOI: 10.1099/ijsem.0.003060 -
The Science of the Total Environment Jul 2020In recent years, the Mediterranean area has witnessed an increase of both the frequency and severity of large fires, which appears to be intimately associated with...
In recent years, the Mediterranean area has witnessed an increase of both the frequency and severity of large fires, which appears to be intimately associated with climate and land use changes. To measure the impact of wildfires on living organisms, diverse indicators have been proposed. These indicators of fire severity traditionally rely on quantifying the damage caused to the vegetal component of ecosystems. However, the use of bacterial communities as severity indicators has received less attention. Here, we studied the differences between bacterial communities of three different Mediterranean ecosystems, two shrubby and one arboreal, two months after a large wildfire. Two levels of severity were compared to a control unburnt soil. The results showed that greater fire severity triggers a reduction in the diversity of soil bacterial communities. In high-severity fires, this reduction reached 40.6 and 58.6% of the control values for richness and Shannon's diversity, respectively. We also found that the greatest differences between communities could be attributed first to the severity of the fire, and second to the ecosystem from which they originated. Importantly, species of just five families of bacteria: Oxalobacteraceae, Micrococcaceae, Paenibacillaceae, Bacillaceae and Planococcaceae, became dominant in all three ecosystems. The average frequency increase for particular species was 100 times. However, due to random uncontrolled factors, the species that became dominant in each community were not always the same.
Topics: Bacteria; Ecosystem; Fires; Soil; Wildfires
PubMed: 32320886
DOI: 10.1016/j.scitotenv.2020.138636 -
Current Microbiology Mar 2020Therapeutic potential of biosurfactant (BS) has been improved in recent years. Our present study deals with production of BS from Planococcus maritimus SAMP MCC 3013 in...
Therapeutic potential of biosurfactant (BS) has been improved in recent years. Our present study deals with production of BS from Planococcus maritimus SAMP MCC 3013 in a mineral salt medium (MSM) supplemented with glucose (1.5% w/v). Further, BS has been purified and partially characterized as glycolipid type through our previous publication. Current research article aimed to evaluate biological potential of BS against Mycobacterium tuberculosis, Plasmodium falciparum and cancerous cell lines. Planococcus derived glycolipid BS was found to be a promising inhibitor of M. tuberculosis (MTB) H37Ra at IC 64.11 ± 1.64 μg/mL and MIC at 160.8 ± 1.64 μg/mL. BS also showed growth inhibition of P. falciparum at EC 34.56 ± 0.26 µM. Additionally, BS also displayed the cytotoxicity against HeLa (IC 41.41 ± 4.21 μg/mL), MCF-7 (IC 42.79 ± 6.07 μg/mL) and HCT (IC 31.233 ± 5.08 μg/mL) cell lines. Molecular docking analysis was carried for the most popular glycolipid type BS namely Rhamnolipid (RHL) aiming to interpret the possible binding interaction for anti-tubercular and anti-cancer activity. This analysis revealed the involvement of RHL binding with enoyl reductase (InhA) of M. tuberculosis. Docking studies of RHL with tubulin directed several hydrophobic and Vander Waal interactions to exhibit anti-cancer potential. The present study will be helpful for further development of marine bioactive molecules for therapeutic applications. Their anti-tubercular, anti-plasmodial and cytotoxic activities make BS molecules as a noteworthy candidate to combat several diseases. To the best of our knowledge, this is the first report on projecting the pharmacological potential of Planococcus derived BS.
Topics: Antineoplastic Agents; Antiprotozoal Agents; Antitubercular Agents; Bacterial Proteins; Binding Sites; Cell Line, Tumor; Culture Media; Glucose; HCT116 Cells; HeLa Cells; Humans; Inhibitory Concentration 50; MCF-7 Cells; Microbial Sensitivity Tests; Molecular Docking Simulation; Mycobacterium tuberculosis; Planococcaceae; Plasmodium falciparum; Surface-Active Agents
PubMed: 31897664
DOI: 10.1007/s00284-019-01850-1 -
The Science of the Total Environment Apr 2019The indigenous microorganisms with the ability of metabolising di-(2-ethylhexyl) phthalate (DEHP) in agricultural soils and their interactions with non-degrading...
The indigenous microorganisms with the ability of metabolising di-(2-ethylhexyl) phthalate (DEHP) in agricultural soils and their interactions with non-degrading microbes were revealed by DNA-based stable isotope probing coupled with molecular ecological network. Aside from the previously reported DEHP degraders (family Planococcaceae and genus Sphingobacterium), five OTUs representing bacteria affiliated with genus Brevundimona, class Spartobacteria, genus Singulisphaera, genus Dyella and class Ktedonobacteria were linked with DEHP biodegradation. The analysis of the constructed ecological network based on soil microbial communities demonstrated the negative relationships between DEHP degraders and the dominant family Oxalobacteraceae in soils. Additionally, two cultivable bacteria isolated from the same soils, Rhizobium-1 and Ensifer-1, had strong capabilities in degrading DEHP but their involvement in in situ DEHP degradation was questioned, as their DNA was not labelled with C from DEHP. These findings provide deeper understanding on the indigenous DEHP-degrading communities and will benefit the remediation of phthalate esters contaminated soils.
Topics: Agriculture; Biodegradation, Environmental; Diethylhexyl Phthalate; Microbiota; Oxalobacteraceae; Soil; Soil Microbiology; Soil Pollutants
PubMed: 30743959
DOI: 10.1016/j.scitotenv.2019.01.052 -
Journal of Applied Microbiology Jun 2015Ureolysis drives microbially induced calcium carbonate precipitation (MICP). MICP models typically employ simplified urea hydrolysis kinetics that do not account for...
AIMS
Ureolysis drives microbially induced calcium carbonate precipitation (MICP). MICP models typically employ simplified urea hydrolysis kinetics that do not account for cell density, pH effect or product inhibition. Here, ureolysis rate studies with whole cells of Sporosarcina pasteurii aimed to determine the relationship between ureolysis rate and concentrations of (i) urea, (ii) cells, (iii) NH4+ and (iv) pH (H(+) activity).
METHODS AND RESULTS
Batch ureolysis rate experiments were performed with suspended cells of S. pasteurii and one parameter was varied in each set of experiments. A Michaelis-Menten model for urea dependence was fitted to the rate data (R(2) = 0·95) using a nonlinear mixed effects statistical model. The resulting half-saturation coefficient, Km , was 305 mmol l(-1) and maximum rate constant, Vmax , was 200 mmol l(-1) h(-1) . However, a first-order model with k1 = 0·35 h(-1) fit the data better (R(2) = 0·99) for urea concentrations up to 330 mmol l(-1) . Cell concentrations in the range tested (1 × 10(7) -2 × 10(8) CFU ml(-1) ) were linearly correlated with ureolysis rate (cell dependent Vmax' = 6·4 × 10(-9) mmol CFU(-1) h(-1) ).
CONCLUSIONS
Neither pH (6-9) nor ammonium concentrations up to 0·19 mol l(-1) had significant effects on the ureolysis rate and are not necessary in kinetic modelling of ureolysis. Thus, we conclude that first-order kinetics with respect to urea and cell concentrations are likely sufficient to describe urea hydrolysis rates at most relevant concentrations.
SIGNIFICANCE AND IMPACT OF THE STUDY
These results can be used in simulations of ureolysis driven processes such as microbially induced mineral precipitation and they verify that under the stated conditions, a simplified first-order rate for ureolysis can be employed. The study shows that the kinetic models developed for enzyme kinetics of urease do not apply to whole cells of S. pasteurii.
Topics: Bacterial Proteins; Calcium Carbonate; Hydrolysis; Kinetics; Sporosarcina; Urea; Urease
PubMed: 25809221
DOI: 10.1111/jam.12804 -
Foods (Basel, Switzerland) Jul 2023In order to investigate and develop functional foods of marine origin with hypoglycemic activity, polysaccharide-Zn(II) (EZ) complex was first prepared by marine...
In order to investigate and develop functional foods of marine origin with hypoglycemic activity, polysaccharide-Zn(II) (EZ) complex was first prepared by marine resourced polysaccharide (EP) and ZnSO and their anti-diabetes activities against high-sugar and high-fat-induced diabetic mice were evaluated. The detailed structural characterization of EZ was elucidated by UV-Vis spectroscopy, infrared spectroscopy, and monosaccharide composition determination. The pharmacological research suggests that EZ has a potent hypoglycemic effect on high-sugar and high-fat-induced diabetic mice by inhibiting insulin resistance, improving dyslipidemia, decreasing inflammatory status, repairing pancreas damage, as well as activating the IRS/PI3K/AKT signaling pathway and regulating GLUT2 gene expression. At the same time, microbiota analysis indicates that a high dose of EZ could enhance the abundance of dominant species, such as , , , , and , in intestinal microbiota distribution. Thus, EZ could be considered as a potential candidate for developing an ingredient of functional foods for Zn(II) supplements with hypoglycemic activity.
PubMed: 37569125
DOI: 10.3390/foods12152854 -
Astrobiology Nov 2019Extraterrestrial environments encompass physicochemical conditions and habitats that are unknown on Earth, such as perchlorate-rich brines that can be at least...
Extraterrestrial environments encompass physicochemical conditions and habitats that are unknown on Earth, such as perchlorate-rich brines that can be at least temporarily stable on the martian surface. To better understand the potential for life in these cold briny environments, we determined the maximum salt concentrations suitable for growth (MSCg) of six different chloride and perchlorate salts at 25°C and 4°C for the extremotolerant cold- and salt-adapted bacterial strain . Growth was measured through colony-forming unit (CFU) counts, while cellular and colonial phenotypic stress responses were observed through visible light, fluorescence, and scanning electron microscopy. Our data show the following: (1) The tolerance to high salt concentrations can be increased through a stepwise inoculation toward higher concentrations. (2) Ion-specific factors are more relevant for the growth limitation of in saline solutions than single physicochemical parameters like ionic strength or water activity. (3) shows the highest microbial sodium perchlorate tolerance described so far. However, (4) MSCg values are higher for all chlorides compared to perchlorates. (5) The MSCg for calcium chloride was increased by lowering the temperature from 25°C to 4°C, while sodium- and magnesium-containing salts can be tolerated at 25°C to higher concentrations than at 4°C. (6) Depending on salt type and concentration, cells show distinct phenotypic stress responses such as novel types of colony morphology on agar plates and biofilm-like cell clustering, encrustation, and development of intercellular nanofilaments. This study, taken in context with previous work on the survival of extremophiles in Mars-like environments, suggests that high-concentrated perchlorate brines on Mars might not be habitable to any present organism on Earth, but extremophilic microorganisms might be able to evolve thriving in such environments.
Topics: Chlorides; Cold Temperature; Cold-Shock Response; Extraterrestrial Environment; Extreme Environments; Extremophiles; Mars; Osmolar Concentration; Perchlorates; Planococcaceae; Salt Stress; Salts
PubMed: 31386567
DOI: 10.1089/ast.2019.2069 -
International Journal of Systematic and... Nov 2018A novel Gram-stain-positive, coccoid or short rod-shaped, moderate-orange-pigmented, halotolerant and psychrotolerant bacterium, designated strain SCU63, was isolated...
A novel Gram-stain-positive, coccoid or short rod-shaped, moderate-orange-pigmented, halotolerant and psychrotolerant bacterium, designated strain SCU63, was isolated from a saline soil sample in China, and characterized by a polyphasic taxonomic approach. 16S rRNA gene sequence similarity of strain SCU63 to species in the genera Planococcus and Planomicrobium ranged from 96.5 to 98.6 %. Phylogenetic trees as well as diagnostic signature nucleotides in the 16S rRNA gene sequence supported the view that this strain should be assigned to the genus Planococcus. Further, average nucleotide identity and digital DNA-DNA hybridization analyses confirmed the separate species status of strain SCU63 relative to the closely related taxa. The isolate grew at 0-40 °C (optimum, 30-35 °C), at pH 6.5-9.0 (pH 7.0-7.5) and in the presence of 0-15 % (w/v) NaCl (3 %). The principal fatty acids were anteiso-C15 : 0, C16 : 1ω7c alcohol, iso-C16 : 0 and iso-C14 : 0, and the dominant isoprenoid quinones were MK-8 and MK-7. The peptidoglycan type was determined to be A4α (l-Lys-d-Glu), and the polar lipids contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, one unidentified aminophospholipid and one unidentified lipid. The DNA G+C content was 44.6 mol%. Based on the genotypic, phenotypic and chemotaxonomic data, strain SCU63 can be classified as a novel species in the genus Planococcus, for which the name Planococcushalotolerans sp. nov. is proposed. The type strain is SCU63 (=CGMCC 1.13628=KCTC 43001).
Topics: Bacterial Typing Techniques; Base Composition; China; DNA, Bacterial; Fatty Acids; Nucleic Acid Hybridization; Peptidoglycan; Phospholipids; Phylogeny; Pigmentation; Planococcus Bacteria; RNA, Ribosomal, 16S; Salinity; Sequence Analysis, DNA; Soil; Soil Microbiology; Vitamin K 2
PubMed: 30265231
DOI: 10.1099/ijsem.0.003019 -
Letters in Applied Microbiology Feb 2019Biocalcification through the use of ureolytic bacteria and biochemical activities has evolved in recent decades into a fervent resourceful effective technology suitable...
Biocalcification through the use of ureolytic bacteria and biochemical activities has evolved in recent decades into a fervent resourceful effective technology suitable for soil stabilization, crack repair and bioremediation. Extensive studies have been carried out on numerous ureolytic bacterial species isolated from soils and sewage samples. However, very limited attention has been given to limestone caves with natural calcite formations as a possible source for isolation of ureolytic bacteria. In this study, bacterial isolates were recovered from limestone cave samples to determine their suitability for biocalcification. Twenty-seven morphologically distinct bacterial isolates were identified by partial 16S rRNA gene sequencing and their various genetic diversity was characterized according to their phylogenetic affiliations. Based on the molecular identification, Sporosarcina was the most abundant genus among all the ureolytic isolates, while the rest belonged to Pseudogracilibacillus and Bacillus genera. Analytical analysis on urease measurement showed that urease activities for the isolates ranged from 1·130 to 21·513 mol urea hydrolysed per minute, with isolate NB33 achieving the highest value and TSB4 achieving the lowest value. The estimated CaCO precipitates for the isolates ranged from 4·04 to 17·26 mg ml , with isolate NB30 achieving the highest value and TSB20 achieving the lowest value. The findings in this study demonstrated that the ureolytic bacteria from limestone caves are promising bio-calcifying agents. SIGNIFICANCE AND IMPACT OF THE STUDY: Ureolytic bacteria continues to play an important role as microbial tools used in geotechnical engineering for soil biocalcification. Microbial strains with the ability to produce urease enzyme and induce calcium carbonate mineral are often isolated from soil, water and sludge samples. However, screening for these essential microbes from extreme regions such as caves are rarely investigated. In this study, native bacteria which were isolated from limestone cave samples are identified and characterized. The findings suggested that these ureolytic bacterial isolates have the potential to serve as suitable alternative microbial agents for soil strengthening and stabilization.
Topics: Bacillaceae; Bacillus; Bacteria; Calcium Carbonate; Caves; Phylogeny; RNA, Ribosomal, 16S; Soil; Soil Microbiology; Sporosarcina; Urea; Urease
PubMed: 30537001
DOI: 10.1111/lam.13103