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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 -
Wei Sheng Wu Xue Bao = Acta... Jul 2008Tetrodotoxin and its analogues (TTXs) were responsible for the poisoning incidents associated with snail Nassarius spp. We studied bacteria isolated from toxic snails as...
OBJECTIVE
Tetrodotoxin and its analogues (TTXs) were responsible for the poisoning incidents associated with snail Nassarius spp. We studied bacteria isolated from toxic snails as well as their habitat to probe into the relationship between bacteria and toxicity of nassariid gastropod.
METHODS
Two snail samples were collected from Sheyang, Jiangsu Province on June 13 and 19, 2006, and the toxicity of the snail samples was tested with mouse bioassay method. Bacteria were isolated from the snail samples and from their habitat. A part of isolated bacteria were then cultured in the lab, and TTX in bacteria were screened with an ELISA method.
RESULTS
The snails collected were identified as Nassarius semiplicatus, and the toxicity of the 2 samples were 247 mouse unit (MU) and 270 MU / 100 g tissue (wet weight), respectively. TTX was detected in 9 strains among the 14 strains of bacteria isolated from the snail samples and their habitat. TTX content in the toxic strains was very low, which ranged from 15 ng/g to 96 ng/g. Partial of the 16S ribosomal DNA (rDNA) of the toxic strains were then sequenced after PCR amplification, and the toxic strains of bacteria were tentatively identified based on the alignment of these sequences with published data. Toxic strains were closely affiliated with Vibrio, Shewanella, Planococcus, Marinomonas, Photobacterium.
CONCLUSION
These findings suggested that TTX-producing bacteria may play an important role in TTX production or accumulation in nassariid gastropod.
Topics: Animals; Bacteria; Calibration; DNA, Ribosomal; Ecosystem; Mice; Phylogeny; Sequence Analysis, DNA; Snails; Tetrodotoxin
PubMed: 18837369
DOI: No ID Found -
International Journal of Systematic and... Mar 2005An aerobic, motile, Gram-positive strain, DX3-12(T), was isolated from coastal sediment of the Eastern China Sea in Fujian Province, China, and was identified by means...
Planomicrobium chinense sp. nov., isolated from coastal sediment, and transfer of Planococcus psychrophilus and Planococcus alkanoclasticus to Planomicrobium as Planomicrobium psychrophilum comb. nov. and Planomicrobium alkanoclasticum comb. nov.
An aerobic, motile, Gram-positive strain, DX3-12(T), was isolated from coastal sediment of the Eastern China Sea in Fujian Province, China, and was identified by means of polyphasic taxonomy. On the basis of 16S rRNA gene sequence similarity, strain DX3-12(T) was closely related to members of the genera Planomicrobium and Planococcus. 16S rRNA gene sequence similarities between strain DX3-12(T) and Planomicrobium mcmeekinii, Planomicrobium koreense, Planomicrobium okeanokoites, Planococcus psychrophilus and Planococcus alkanoclasticus were 97.8, 97.8, 97.1, 97.5 and 96.4 %, respectively. Chemotaxonomic and physiological properties of strain DX3-12(T) supported its affiliation to the genus Planomicrobium. Strain DX3-12(T) and Planomicrobium mcmeekinii exhibited common phenotypic properties such as the ability to reduce nitrate, but they could be distinguished from each other by physiological and biochemical tests, e.g. acid production from glucose, growth temperature and NaCl concentration requirements. DNA-DNA hybridization further distinguished strain DX3-12(T) from Planomicrobium mcmeekinii at the species level. Therefore, it is proposed that strain DX3-12(T) (=AS 1.3454(T)=JCM 12466(T)) represents a novel species, Planomicrobium chinense sp. nov. Based on 16S rRNA gene sequence similarities, signature nucleotides, cell morphology and physiological and biochemical properties, Planococcus psychrophilus and Planococcus alkanoclasticus have been transferred to the genus Planomicrobium as Planomicrobium psychrophilum comb. nov. (type strain DSM 14507(T)=MTCC 3812(T)) and Planomicrobium alkanoclasticum comb. nov. (type strain NCIMB 13489(T)=CIP 107718(T)), respectively.
Topics: Base Sequence; China; DNA, Bacterial; DNA, Ribosomal; Genes, rRNA; Geologic Sediments; Gram-Positive Bacteria; Molecular Sequence Data; Phenotype; Phylogeny; RNA, Ribosomal, 16S; Seawater; Sequence Analysis, DNA
PubMed: 15774646
DOI: 10.1099/ijs.0.63340-0 -
Protein Expression and Purification Sep 2016Lactase deficiency problem discourages many adults from consuming milk as a major source of micro- and macronutrients. Enzymatic hydrolysis of lactose is an ideal...
Lactase deficiency problem discourages many adults from consuming milk as a major source of micro- and macronutrients. Enzymatic hydrolysis of lactose is an ideal solution for this problem but such processing adds significant costs. In this study, a cold active β-galactosidase from Planococcus sp-L4 (bgal) was optimized for expression of recombinant "BGalP" in Pichia pastoris. As a result of codon optimization, the codon adaptation index was improved from 0.58 to 0.85 after replacing rare codons. After transformation of two P. pastoris strains (KM71H and GS115), the activity of BGalP enzyme was measured in the culture supernatants using ortho-Nitrophenyl-β-galactoside (ONPG). Maximal activity was recorded as 3.7U/ml on day 11 in KM71H clone #2 which was 20% higher than the best GS115 clone. Activity measurements under different conditions indicated optimal activity at pH 6.5. It was active at temperatures ranging from 0 to 55°C with deactivation occurring at or above 60°C. Protein analysis of the crude ultra-filtrate showed the enzyme was ∼75kDa and was the major constituent (85%) of the sample. This enzyme have the potential to find utility for the breakdown of lactose in chilled milk and subsequently can be deactivated by pasteurization. The use of BGalP would minimize energy consumption thus decreasing cost and also help to preserve the nutritional elements of the milk.
Topics: Animals; Codon; Cold Temperature; Enzyme Activation; Gene Expression; Hydrogen-Ion Concentration; Lactose; Milk; Pichia; Planococcus Bacteria; Recombinant Fusion Proteins; Transformation, Genetic; beta-Galactosidase
PubMed: 26361980
DOI: 10.1016/j.pep.2015.09.008 -
Canadian Journal of Microbiology Aug 1998The enzymatic activity of phosphoglycerate mutase (Pgm) from three gram-positive endospore-forming bacteria (Bacillus subtilis, Clostridium perfringens, and Sporosarcina... (Comparative Study)
Comparative Study
The enzymatic activity of phosphoglycerate mutase (Pgm) from three gram-positive endospore-forming bacteria (Bacillus subtilis, Clostridium perfringens, and Sporosarcina ureae) requires Mn2+ and is very sensitive to pH; at low concentrations of Mn2+, a pH change from 8 to 6 resulted in greater than 30- to 200-fold decreases in the activity of these Pgms. However, Pgm deactivation at pH 6 was reversed by shifting the enzyme to pH 7 or 8. Free Mn2+ was not directly involved in Pgm catalysis, although enzyme-bound Mn2+ may be involved. The rate of catalysis by Mn(2+)-containing Pgm was also slightly pH dependent, although the Km for 3-phosphoglyceric acid appeared to be the same at pH 6, 7, and 8. These findings suggest that Mn2+ binds to catalytically inactive Pgm and converts it to a catalytically competent form, and further, that pH influences the efficiency with which the enzyme binds Mn2+. The extreme pH sensitivity of the Mn(2+)-dependent Pgms supports a model in which this enzyme is inhibited during sporulation by acidification of the forespore, thus allowing accumulation of the spore's large depot of 3-phosphoglyceric acid. The activity of Pgm from two closely related gram-positive bacteria that do not form spores (Planococcus citreus and Staphylococcus saprophyticus) also requires Mn2+ and is pH sensitive. In contrast, the Pgm activities from two more distantly related non-endospore-forming gram-positive bacteria (Micrococcus luteus and Streptomyces coelicolor) are neither dependent on metal ions nor particularly sensitive to pH.
Topics: Bacillus subtilis; Clostridium perfringens; Gram-Positive Endospore-Forming Bacteria; Hydrogen-Ion Concentration; Kinetics; Manganese; Micrococcus luteus; Phosphoglycerate Mutase; Species Specificity; Staphylococcus; Streptomyces
PubMed: 9830105
DOI: 10.1139/cjm-44-8-759 -
BMC Microbiology Apr 2013In all branches of life there are plenty of symbiotic associations. Insects are particularly well suited to establishing intracellular symbiosis with bacteria, providing...
BACKGROUND
In all branches of life there are plenty of symbiotic associations. Insects are particularly well suited to establishing intracellular symbiosis with bacteria, providing them with metabolic capabilities they lack. Essential primary endosymbionts can coexist with facultative secondary symbionts which can, eventually, establish metabolic complementation with the primary endosymbiont, becoming a co-primary. Usually, both endosymbionts maintain their cellular identity. An exception is the endosymbiosis found in mealybugs of the subfamily Pseudoccinae, such as Planococcus citri, with Moranella endobia located inside Tremblaya princeps.
RESULTS
We report the genome sequencing of M. endobia str. PCVAL and the comparative genomic analyses of the genomes of strains PCVAL and PCIT of both consortium partners. A comprehensive analysis of their functional capabilities and interactions reveals their functional coupling, with many cases of metabolic and informational complementation. Using comparative genomics, we confirm that both genomes have undergone a reductive evolution, although with some unusual genomic features as a consequence of coevolving in an exceptional compartmentalized organization.
CONCLUSIONS
M. endobia seems to be responsible for the biosynthesis of most cellular components and energy provision, and controls most informational processes for the consortium, while T. princeps appears to be a mere factory for amino acid synthesis, and translating proteins, using the precursors provided by M. endobia. In this scenario, we propose that both entities should be considered part of a composite organism whose compartmentalized scheme (somehow) resembles a eukaryotic cell.
Topics: Animals; Betaproteobacteria; DNA, Bacterial; Enterobacteriaceae; Genome, Bacterial; Hemiptera; Molecular Sequence Data; Sequence Analysis, DNA; Symbiosis
PubMed: 23548081
DOI: 10.1186/1471-2180-13-74 -
Life (Basel, Switzerland) Jan 2021(1) Background: Future missions to potentially habitable places in the Solar System require biochemistry-independent methods for detecting potential alien life forms....
(1) Background: Future missions to potentially habitable places in the Solar System require biochemistry-independent methods for detecting potential alien life forms. The technology was not advanced enough for onboard machine analysis of microscopic observations to be performed in past missions, but recent increases in computational power make the use of automated in-situ analyses feasible. (2) Methods: Here, we present a semi-automated experimental setup, capable of distinguishing the movement of abiotic particles due to Brownian motion from the motility behavior of the bacteria . Supervised machine learning algorithms were also used to specifically identify these species based on their characteristic motility behavior. (3) Results: While we were able to distinguish microbial motility from the abiotic movements due to Brownian motion with an accuracy exceeding 99%, the accuracy of the automated identification rates for the selected species does not exceed 82%. (4) Conclusions: Motility is an excellent biosignature, which can be used as a tool for upcoming life-detection missions. This study serves as the basis for the further development of a microscopic life recognition system for upcoming missions to Mars or the ocean worlds of the outer Solar System.
PubMed: 33445805
DOI: 10.3390/life11010044 -
Journal of Applied Microbiology Mar 2009Grey mould caused by Botrytis cinerea is an economically important disease of strawberries in Tunisia and worldwide. The aim of this study was to select effective...
AIMS
Grey mould caused by Botrytis cinerea is an economically important disease of strawberries in Tunisia and worldwide. The aim of this study was to select effective halophilic bacteria from hypersaline ecosystems and evaluate the abilities of antifungal bacteria to secrete extracellular hydrolytic enzymes, anti-Botrytis metabolites and volatiles.
METHODS AND RESULTS
Grey mould was reduced in strawberry fruits treated with halophilic antagonists and artificially inoculated with B. cinerea. Thirty strains (20.2%) were active against the pathogen and reduced the percentage of fruits infected after 3 days of storage at 20 degrees C, from 50% to 91.66%. The antagonists were characterized by phenotypic tests and 16S rDNA sequencing. They were identified as belonging to one of the species: Virgibacillus marismortui, B. subtilis, B. pumilus, B. licheniformis, Terribacillus halophilus, Halomonas elongata, Planococcus rifietoensis, Staphylococcus equorum and Staphylococcus sp. The effective isolates were tested for antifungal secondary metabolites.
CONCLUSIONS
Moderately halophilic bacteria may be useful in biological control against this pathogen during postharvest storage of strawberries.
SIGNIFICANCE AND IMPACT OF THE STUDY
The use of such bacteria may constitute an important alternative to synthetic fungicides. These moderate halophiles can be exploited in commercial production and application of the effective strains under storage and greenhouse conditions.
Topics: Antibiosis; Bacteria; Botrytis; Fragaria; Hydrolases; Pest Control, Biological; Polymerase Chain Reaction; RNA, Ribosomal, 16S
PubMed: 19191973
DOI: 10.1111/j.1365-2672.2008.04053.x -
PloS One 2022Auxospore production is a sexual reproductive strategy by diatoms to re-attain normal size after the size-reducing effect of clonal reproduction. Aside from the minimum...
Auxospore production is a sexual reproductive strategy by diatoms to re-attain normal size after the size-reducing effect of clonal reproduction. Aside from the minimum size threshold used as a sex clock by diatoms, the environmental or chemical triggers that can induce sex in diatoms are still not well understood. Here we investigated the influence of six marine bacteria from five families on the production of sexual cells and auxospores of the ubiquitous marine polar centric diatom, Odontella sp. Microbiome association and co-occurrence with the diatom in culture and in nature were investigated using 16S rRNA amplicon sequencing. Indole acetic acid (IAA) secretion, a phytohormone that regulates plants' growth and sexual development, was explored as a potential inducer of sexual reproduction in Odontella and compared between bacterial associates. We found that Odontella co-cultured with Flavobacteriaceae (Polaribacter and Cellulophaga) have significantly more sexual cells and auxospores than bacteria-free Odontella and Odontella co-cultured with other bacteria from Vibrionaceae (Vibrio), Pseudoalteromonadaceae (Pseudoalteromonas), Rhodobacteraceae (Sulfitobacter), or Planococcaceae (Planococcus) family. Differences in IAA secretion were observed between bacterial isolates, but this did not correspond consistently with the diatom's clonal growth or production of sexual cells and auxospores. Microbiome composition survey of Odontella cultures showed that the diatom harbors homologous sequences of the four bacterial isolates at varying proportions, with Sulfitobacter and Polaribacter at high abundances. Microbiome surveys at Santa Cruz Wharf, Monterey Bay, from 2014-2015 showed that Odontella abundance is positively correlated with Flavobacteriaceae and Rhodobacteraceae abundances. Our study demonstrates that specific members of the diatom microbiome can enhance the host's sexual reproduction, with the interkingdom interaction driven by partner compatibility and long-term association. Sex-enhancing bacteria may even be needed by the diatom host to carry out the optimal inducement of sex under normal conditions, allowing for size restitution and maintaining genetic diversity in culture and in nature.
Topics: Humans; Animals; Diatoms; RNA, Ribosomal, 16S; Plant Growth Regulators; Microbiota; Arthropods; Reproduction; Rhodobacteraceae
PubMed: 36260629
DOI: 10.1371/journal.pone.0276305 -
Frontiers in Microbiology 2020This study aims at exploiting salinity stress as an innovative, simple, and cheap method to enhance the production of antioxidant metabolites and enzymes from bacteria...
This study aims at exploiting salinity stress as an innovative, simple, and cheap method to enhance the production of antioxidant metabolites and enzymes from bacteria for potential application as functional additives to foods and pharmaceuticals. We investigated the physiological and biochemical responses of four bacterial isolates, which exhibited high tolerance to 20% NaCl (wt/vol), out of 27 bacterial strains isolated from Aushazia Lake, Qassim region, Saudi Arabia. The phylogenetic analysis of the 16S rRNA genes of these four isolates indicated that strains ST1 and ST2 belong to genus , whereas strains ST3 and ST4 belong to genus . Salinity stress differentially induced oxidative damage, where strains ST3 and ST4 showed increased lipid peroxidation, lipoxygenase, and xanthine oxidase levels. Consequently, high antioxidant contents were produced to control oxidative stress, particularly in ST3 and ST4. These two strains showed increased glutathione cycle, phenols, flavonoids, antioxidant capacity, catalase, and/or superoxide dismutase (SOD). Interestingly, the production of glutathione by strains was some thousand folds greater than by higher plants. On the other hand, the induction of antioxidants in ST1 and ST2 was restricted to phenols, flavonoids, peroxidase, glutaredoxin, and/or SOD. The hierarchical analysis also supported strain-specific responses. This is the first report that exploited salinity stress for promoting the production of antioxidants from bacterial isolates, which can be utilized as postbiotics for promising applications in foods and pharmaceuticals.
PubMed: 33042068
DOI: 10.3389/fmicb.2020.561816