scholarly journals FabF Is Required for Piezoregulation ofcis-Vaccenic Acid Levels and Piezophilic Growth of the Deep-Sea Bacterium Photobacterium profundum Strain SS9

2000 ◽  
Vol 182 (5) ◽  
pp. 1264-1271 ◽  
Author(s):  
Eric E. Allen ◽  
Douglas H. Bartlett
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
Deep Sea ◽  
Unsaturated Fatty Acids ◽  
Acyl Carrier Protein ◽  
Vaccenic Acid ◽  
Bacterial Species ◽  
Elevated Pressure ◽  
Wild Type ◽  
Photobacterium Profundum

ABSTRACT To more fully explore the role of unsaturated fatty acids in high-pressure, low-temperature growth, the fabF gene from the psychrotolerant, piezophilic deep-sea bacteriumPhotobacterium profundum strain SS9 was characterized and its role and regulation were examined. An SS9 strain harboring a disruption in the fabF gene (strain EA40) displayed growth impairment at elevated hydrostatic pressure concomitant with diminishedcis-vaccenic acid (18:1) production. However, growth ability at elevated pressure could be restored to wild-type levels by the addition of exogenous 18:1 to the growth medium. Transcript analysis did not indicate that the SS9 fabF gene is transcriptionally regulated, suggesting that the elevated 18:1 levels produced in response to pressure increase result from posttranscriptional changes. Unlike many pressure-adapted bacterial species such as SS9, the mesophile Escherichia coli did not regulate its fatty acid composition in an adaptive manner in response to changes in hydrostatic pressure. Moreover, an E. coli fabF strain was as susceptible to elevated pressure as wild-type cells. It is proposed that the SS9 fabF product, β-ketoacyl–acyl carrier protein synthase II has evolved novel pressure-responsive characteristics which facilitate SS9 growth at high pressure.

Monounsaturated but Not Polyunsaturated Fatty Acids Are Required for Growth of the Deep-Sea BacteriumPhotobacterium profundum SS9 at High Pressure and Low Temperature

1999 ◽  
Vol 65 (4) ◽  
pp. 1710-1720 ◽  
Author(s):  
Eric E. Allen ◽  
Daniel Facciotti ◽  
Douglas H. Bartlett
Keyword(s):  
Fatty Acids ◽  
High Pressure ◽  
Fatty Acid ◽  
Low Temperature ◽  
Mutant Strain ◽  
Deep Sea ◽  
High Pressures ◽  
Unsaturated Fatty Acids ◽  
Temperature Sensitive ◽  
Pressure Sensitive

ABSTRACT There is considerable evidence correlating the production of increased proportions of membrane unsaturated fatty acids (UFAs) with bacterial growth at low temperatures or high pressures. In order to assess the importance of UFAs to microbial growth under these conditions, the effects of conditions altering UFA levels in the psychrotolerant piezophilic deep-sea bacterium Photobacterium profundum SS9 were investigated. The fatty acids produced byP. profundum SS9 grown at various temperatures and pressures were characterized, and differences in fatty acid composition as a function of phase growth, and between inner and outer membranes, were noted. P. profundum SS9 was found to exhibit enhanced proportions of both monounsaturated (MUFAs) and polyunsaturated (PUFAs) fatty acids when grown at a decreased temperature or elevated pressure. Treatment of cells with cerulenin inhibited MUFA but not PUFA synthesis and led to a decreased growth rate and yield at low temperature and high pressure. In addition, oleic acid-auxotrophic mutants were isolated. One of these mutants, strain EA3, was deficient in the production of MUFAs and was both low-temperature sensitive and high-pressure sensitive in the absence of exogenous 18:1 fatty acid. Another mutant, strain EA2, produced little MUFA but elevated levels of the PUFA species eicosapentaenoic acid (EPA; 20:5n-3). This mutant grew slowly but was not low-temperature sensitive or high-pressure sensitive. Finally, reverse genetics was employed to construct a mutant unable to produce EPA. This mutant, strain EA10, was also not low-temperature sensitive or high-pressure sensitive. The significance of these results to the understanding of the role of UFAs in growth under low-temperature or high-pressure conditions is discussed.

scholarly journals THE INFLUENCE OF HIGH HYDROSTATIC PRESSURE ON COCAINE AND VERATRINE ACTION IN A VERTEBRATE NERVE

1959 ◽  
Vol 42 (3) ◽  
pp. 647-653 ◽  
Author(s):  
Norman L. Gershfeld ◽  
Abraham M. Shanes
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
Sciatic Nerve ◽  
Action Potential ◽  
High Hydrostatic Pressure ◽  
Elevated Pressure

The application of high hydrostatic pressure to toad sciatic nerve causes a gain in sodium and a loss of potassium which are not affected by cocaine. However, cocaine action is enhanced by high pressure when counteracting veratrine depolarization and when blocking the action potential. Various effects of elevated pressure on the after-potentials are presented and the role of ions in these processes is discussed.

scholarly journals Rupture of the Cell Envelope by Decompression of the Deep-Sea Methanogen Methanococcus jannaschii

2002 ◽  
Vol 68 (3) ◽  
pp. 1458-1463 ◽  
Author(s):  
Chan Beum Park ◽  
Douglas S. Clark
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Hydrostatic Pressure ◽  
Deep Sea ◽  
Cell Envelope ◽  
Cell Lysis ◽  
Methanococcus Jannaschii ◽  
Hyperbaric Pressure ◽  
High Pressure High Temperature ◽  
Rapid Decompression

ABSTRACT The effect of decompression on the structure of Methanococcus jannaschii, an extremely thermophilic deep-sea methanogen, was studied in a novel high-pressure, high-temperature bioreactor. The cell envelope of M. jannaschii appeared to rupture upon rapid decompression (ca. 1 s) from 260 atm of hyperbaric pressure. When decompression from 260 atm was performed over 5 min, the proportion of ruptured cells decreased significantly. In contrast to the effect produced by decompression from hyperbaric pressure, decompression from a hydrostatic pressure of 260 atm did not induce cell lysis.

scholarly journals Deep Sea Microbes Probed by Incoherent Neutron Scattering Under High Hydrostatic Pressure

2014 ◽  
Vol 228 (10-12) ◽  
Author(s):  
Judith Peters ◽  
Nicolas Martinez ◽  
Grégoire Michoud ◽  
Anaïs Cario ◽  
Bruno Franzetti ◽  
...  
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
Neutron Scattering ◽  
Deep Sea ◽  
High Hydrostatic Pressure ◽  
Deep Biosphere ◽  
Incoherent Neutron Scattering ◽  
Incoherent Neutron ◽  
High Pressure Environment ◽  
Marine Biosphere

AbstractThe majority of the biosphere is a high pressure environment. Around 70% of the marine biosphere lies at depths below 1000 m, i.e. at pressures of 100 bars or higher. To survive in these environments, deep-biosphere organisms have adapted to life at high pressure.

scholarly journals Effects of High Hydrostatic Pressure on Coastal Bacterial Community Abundance and Diversity

2014 ◽  
Vol 80 (19) ◽  
pp. 5992-6003 ◽  
Author(s):  
Angeliki Marietou ◽  
Douglas H. Bartlett
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
Surface Waters ◽  
Deep Sea ◽  
Sea Surface ◽  
Bacterial Populations ◽  
Content Type ◽  
Microbial Life ◽  
Community Changes ◽  
Abundance And Diversity

ABSTRACTHydrostatic pressure is an important parameter influencing the distribution of microbial life in the ocean. In this study, the response of marine bacterial populations from surface waters to pressures representative of those under deep-sea conditions was examined. Southern California coastal seawater collected 5 m below the sea surface was incubated in microcosms, using a range of temperatures (16 to 3°C) and hydrostatic pressure conditions (0.1 to 80 MPa). Cell abundance decreased in response to pressure, while diversity increased. The morphology of the community also changed with pressurization to a predominant morphotype of small cocci. The pressure-induced community changes included an increase in the relative abundance ofAlphaproteobacteria,Gammaproteobacteria,Actinobacteria, andFlavobacterialargely at the expense ofEpsilonproteobacteria. Culturable high-pressure-surviving bacteria were obtained and found to be phylogenetically similar to isolates from cold and/or deep-sea environments. These results provide novel insights into the response of surface water bacteria to changes in hydrostatic pressure.

Microbial Life in the Trenches

2009 ◽  
Vol 43 (5) ◽  
pp. 128-131 ◽  
Author(s):  
Douglas H. Bartlett
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
Deep Sea ◽  
Ocean Engineering ◽  
Deep Trench ◽  
Microbial Life ◽  
Elevated Hydrostatic Pressure ◽  
Pure Cultures ◽  
History Of ◽  
Challenger Deep

AbstractMicrobiologists have been making use of advances in ocean engineering to explore life in deep-sea trenches for decades, including for many years preceding man’s conquest of the Challenger Deep. This has fostered the development of an unusual branch of microbiology, referred to as high-pressure microbiology. Evidence for deep-trench microbes that grow best at elevated hydrostatic pressure was first obtained in the early 1950s, and isolates were obtained in pure cultures beginning in the early 1980s. Here I describe some of the history of deep-trench microbiology and the characteristics of microbial life in the trenches.

scholarly journals Research and Analysis of Pressure-Maintaining Trapping Instrument for Macro-Organisms in Hadal Trenches

2020 ◽  
Vol 8 (8) ◽  
pp. 596
Author(s):  
Hao Wang ◽  
Jiawang Chen ◽  
Yuhong Wang ◽  
Jiasong Fang ◽  
Yuping Fang
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
Deep Sea ◽  
High Hydrostatic Pressure ◽  
Explicit Method ◽  
Working Process ◽  
Ecosystem Research ◽  
Factors Affecting ◽  
Pressure Tests ◽  
Orthogonal Tests

The ecosystem of the abyss is one of the fields that humans hardly know. The ultra-high hydrostatic pressure makes it very difficult to obtain abyssal organisms. Samples are often severely broken during recovery due to changes in environmental pressure, temperature, and other factors. Currently, there are no macro-organism samplers suitable for the abyss. The development of a pressure-maintaining sampler for the abyss is a prerequisite for abyssal ecosystem research. This paper mainly proposed a pressure-maintaining trapping instrument (PMTI) designed to work at a depth above 10,000 m. Unlike typical deep-sea equipment, this instrument is lightweight (about 65 kg in water). The instrument adopts a new structure, using a hollow piston as the sampling space and sealing the mechanism with O-rings at both ends of the piston, thus avoiding sealing methods such as ball valves and greatly reducing the weight of the equipment. The structure and working process of the instrument are described in detail in this paper. Meanwhile, in this paper, the movement resistance of the piston (mainly the resistance of the O-ring) is analyzed using a dynamic explicit method in Abaqus. The factors affecting the friction of the O-rings are analyzed via the method of orthogonal tests and ANOVA. In addition, high-pressure tests were conducted on key parts of the instrument, and the results showed that the instrument works well at 100 MPa.

scholarly journals The Deep-Sea Bacterium Photobacterium profundum SS9 Utilizes Separate Flagellar Systems for Swimming and Swarming under High-Pressure Conditions

2008 ◽  
Vol 74 (20) ◽  
pp. 6298-6305 ◽  
Author(s):  
Emiley A. Eloe ◽  
Federico M. Lauro ◽  
Rudi F. Vogel ◽  
Douglas H. Bartlett
Keyword(s):  
High Pressure ◽  
Gene Cluster ◽  
Deep Sea ◽  
Gene Clusters ◽  
Maximum Pressure ◽  
Swimming Velocity ◽  
Flagellar Motor ◽  
Lateral Flagellum ◽  
Photobacterium Profundum ◽  
Flagellum Gene

ABSTRACT Motility is a critical function needed for nutrient acquisition, biofilm formation, and the avoidance of harmful chemicals and predators. Flagellar motility is one of the most pressure-sensitive cellular processes in mesophilic bacteria; therefore, it is ecologically relevant to determine how deep-sea microbes have adapted their motility systems for functionality at depth. In this study, the motility of the deep-sea piezophilic bacterium Photobacterium profundum SS9 was investigated and compared with that of the related shallow-water piezosensitive strain Photobacterium profundum 3TCK, as well as that of the well-studied piezosensitive bacterium Escherichia coli. The SS9 genome contains two flagellar gene clusters: a polar flagellum gene cluster (PF) and a putative lateral flagellum gene cluster (LF). In-frame deletions were constructed in the two flagellin genes located within the PF cluster (flaA and flaC), the one flagellin gene located within the LF cluster (flaB), a component of a putative sodium-driven flagellar motor (motA2), and a component of a putative proton-driven flagellar motor (motA1). SS9 PF flaA, flaC, and motA2 mutants were defective in motility under all conditions tested. In contrast, the flaB and motA1 mutants were defective only under conditions of high pressure and high viscosity. flaB and motA1 gene expression was strongly induced by elevated pressure plus increased viscosity. Direct swimming velocity measurements were obtained using a high-pressure microscopic chamber, where increases in pressure resulted in a striking decrease in swimming velocity for E. coli and a gradual reduction for 3TCK which proceeded up to 120 MPa, while SS9 increased swimming velocity at 30 MPa and maintained motility up to a maximum pressure of 150 MPa. Our results indicate that P. profundum SS9 possesses two distinct flagellar systems, both of which have acquired dramatic adaptations for optimal functionality under high-pressure conditions.

scholarly journals RecD Function Is Required for High-Pressure Growth of a Deep-Sea Bacterium

1999 ◽  
Vol 181 (8) ◽  
pp. 2330-2337 ◽  
Author(s):  
Kelly A. Bidle ◽  
Douglas H. Bartlett
Keyword(s):  
High Pressure ◽  
Deep Sea ◽  
Genomic Library ◽  
Plasmid Stability ◽  
Stop Codon ◽  
Dna Recombination ◽  
Repair Gene ◽  
E Coli ◽  
Pressure Sensitive ◽  
Photobacterium Profundum

ABSTRACT A genomic library derived from the deep-sea bacteriumPhotobacterium profundum SS9 was conjugally delivered into a previously isolated pressure-sensitive SS9 mutant, designated EC1002 (E. Chi and D. H. Bartlett, J. Bacteriol. 175:7533–7540, 1993), and exconjugants were screened for the ability to grow at 280-atm hydrostatic pressure. Several clones were identified that had restored high-pressure growth. The complementing DNA was localized and in all cases found to possess strong homology torecD, a DNA recombination and repair gene. EC1002 was found to be deficient in plasmid stability, a phenotype also seen inEscherichia coli recD mutants. The defect in EC1002 was localized to a point mutation that created a stop codon within the recD gene. Two additional recDmutants were constructed by gene disruption and were both found to possess a pressure-sensitive growth phenotype, although the magnitude of the defect depended on the extent of 3′ truncation of the recD coding sequence. Surprisingly, the introduction of the SS9 recD gene into an E. coli recD mutant had two dramatic effects. At high pressure, SS9recD enabled growth in the E. coli mutant strain under conditions of plasmid antibiotic resistance selection and prevented cell filamentation. Both of these effects were recessive to wild-type E. coli recD. These results suggest that the SS9recD gene plays an essential role in SS9 growth at high pressure and that it may be possible to identify additional aspects of RecD function through the characterization of this activity.

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