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Phase contrast (a) and transmission electron (b) micrographs of cells of strain 37 T . Bars, 5 and 0 ? 6 m m, respectively. Bright areas within the cells observed by phase contrast microscopy are gas vacuoles. The characteristic morphology of the subunit gas vesicles, i.e. their cylindrical shape with conical polar caps, is shown in (b).
Source publication
A gas vacuolate bacterium, designated strain 37T, was isolated from a sea ice core collected from Point Barrow, Alaska, USA. Cells of strain 37T were large (6-14 microm in length), rod-shaped, contained gas vacuoles of two distinct morphologies, and grew well at NaCl concentrations of 1-10 % and at temperatures of -12 to 10 degrees C. The DNA G+C c...
Contexts in source publication
Context 1
... from the water column and sufficient surface light are present (Staley & Gosink, 1999). The SIMCOs are stratified, containing large varieties of both eukaryotes and prokaryotes. Recent attempts to characterize the bacterial component of SIMCOs have revealed great diversity. To our knowledge, six new genera of the phylum Bacteroidetes (Gosink et al. , 1998; Bowman et al. , 1998a, 1997, 2003; Bowman & Nichols, 2002) and three new genera of Proteo- bacteria (Gosink et al. , 1997; Irgens et al. , 1996; Bowman et al. , 1998b) have been identified within or near the SIMCO, along with known Gram-positive genera (Junge et al. , 1998). Among the SIMCOs, gas vacuolate heterotrophs have been discovered in high numbers from both the Arctic and the Antarctic (Gosink et al. , 1993; Staley et al. , 1989), located either in the water column below or in the ice above the Recently, we reported that a bacterial isolate, designated strain 37 T , isolated from a sea ice core from Point Barrow, Alaska, USA, could grow at subfreezing temperatures, with a generation time of 240 h at 2 12 u C, the lowest recorded growth temperature of any organism verified by a growth curve (Breezee et al. , 2004). Strain 37 T was considered to represent a novel species, which was provisionally named Psychromonas ingrahamii sp. nov. It is most similar to Psychromonas antarctica and other members of the genus Psychromonas , a group of psychrophiles having a wide variety of physiological characteristics including piezophily, facultative psychrophily and halophily (Breezee et al. , 2004; Mountfort et al. , 1998; Kawasaki et al. , 2002; Nogi et al. , 2002; Xu et al. , 2003; Groudieva et al. , 2003; Ivanova et al. , 2004). Here we report additional information for this sea ice isolate to justify recognition of this novel species. Strain 37 was isolated in May 1991 from Elson Lagoon (Point Barrow, Alaska) about 130 cm from the ice–water interface of a 1 ? 8 m ice core (Gosink et al. , 1993). Ordal’s sea water cytophaga medium (SWC m ) prepared in full-strength artificial sea water (ASW) was used for the isolation and routine growth of strain 37 T (Irgens et al. , 1989). Colonies on plates were white, circular, smooth and convex, with an entire margin. Phenotypic characteristics of strain 37 T are summarized in Table 1. Recently, nutrient-rich Cell Strain size, 37 shape we was reported SIMCO and isolated the presence that band in May a (Gosink bacterial of 1991 gas vacuoles from et isolate, al. Elson , 1993). were designated Lagoon deter- Gas strain vacuoles (Point mined 37 for Barrow, T contain , cells isolated grown Alaska) small, from in rigid, about a Difco sea proteinaceous ice 130 marine core cm from broth from subunit Point the 2216 ice–water Barrow, (Becton vesicles Alaska, that interface Dickinson) are USA, gas-permeable, of a via 1 could ? 8 phase m grow ice core contrast reducing at subfreezing (Gosink microscopy cell et al. density temperatures, , 1993). using as Ordal’s compared a with Zeiss sea a water generation with Photomicroscope cytophaga the cytoplasm, time medium of I. Electron 240 and h (SWC at thereby micrographs 2 m 12 ) prepared u C, providing the were lowest in full-strength obtained buoyancy recorded of (Walsby, growth artificial unstained temperature sea 1972). whole water Gas cells (ASW) of vesicles by any using was organism act a used Zeiss as organelles for verified EM900 the isolation transmission by of a motility, growth and regulating curve routine electron (Breezee growth microscope the vertical et of al. strain , at 2004). movement 37 50 T kV. (Irgens Strain Cells of 37 cells et T of al. was via , strain 1989). their considered 37 synthesis Colonies T were to and on represent unusually plates degradation were a large, novel white, (Staley, ranging species, circular, 1980). from which smooth 6 Although to was 14 provisionally and m m gas convex, long vacuolate by with 1 named ? 25 bac- an to 1 teria entire Psychromonas ? 5 m m in margin. wide polar (Fig. 1; ingrahamii Phenotypic sea ice Breezee are sp. characteristics prevalent et al. nov. , 2004), It and is and of most phylogenetically were strain similar arranged 37 T are to diverse, singly, Psychromonas summarized in belonging pairs in antarctica or Table 1. in to short the and Alpha chains. other -, Motility Beta members - and was Gammaproteo- of examined the genus by bacteria incubation Psychromonas and of to , strain a the group Bacteroidetes 37 of T in psychrophiles liquid (Gosink SWC having m & Staley, for 12 a wide 1995), days vari- with the function periodic ety of physiological examination of gas vacuoles characteristics by phase in this contrast environment including microscopy, piezophily, remains and unknown. cells facultative were found psychrophily to be non-motile. and halophily Gas (Breezee vacuoles et were al. , 2004; also visible, Mountfort appearing et al. , 1998; as bright, Kawasaki refractive et al. , 2002; areas Nogi inside et cells al. , (Fig. 1). 2002; Xu Electron et al. , 2003; microscopy Groudieva revealed et al. , 2003; two Ivanova distinct et mor- al. , phologies 2004). Here of we gas report vacuoles: additional numerous information short, wide for cylinders this sea with ice isolate conical to tips; justify and recognition rare, longer of this but novel narrower species. cylinders with conical ends (Fig. 1b). The presence of two gas vacuole types is unusual, having been reported before only in the halophilic archaeon Halobacterium halobium (Walsby, 1994). Cell size, shape and the presence of gas vacuoles were determined for cells grown in Difco marine broth 2216 (Becton Dickinson) via phase contrast microscopy using a Zeiss Photomicroscope I. Electron micrographs were obtained of unstained whole cells by using a Zeiss EM900 transmission electron microscope at 50 kV. Cells of strain 37 T were unusually large, ranging from 6 to 14 m m long by 1 ? 25 to 1 ? 5 m m wide (Fig. 1; Breezee et al. , 2004), and were arranged singly, in pairs or in short chains. Motility was examined by incubation of strain 37 T in liquid SWC m for 12 days with periodic examination by phase contrast microscopy, and cells were found to be non-motile. Gas vacuoles were also visible, appearing as bright, refractive areas inside cells (Fig. 1). Electron microscopy revealed two distinct morphologies of gas vacuoles: numerous short, wide cylinders with conical tips; and rare, longer but narrower cylinders with conical ends (Fig. 1b). The presence of two gas vacuole types is unusual, having been reported before only in the halophilic archaeon Halobacterium halobium (Walsby, 1994). The pH range for growth was tested using SWC m buffered to various pH values with 25 mM solutions of the following buffers: MES, pH 5 ? 7; ACES, pH 6 ? 6; TAPSO, pH 7 ? 4; TAPS, pH 8 ? 3; CHES, pH 9 ? 0) (Dyksterhouse et al. , 1995). Growth at each pH was determined turbidometrically using a Bausch and Lomb 20-D spectrophotometer at 600 nm. Growth was observed at near neutral pH values (pH 6 ? 5, 6 ? 8 and 7 ? 4), but not at moderately acidic (pH 5 ? 0) or basic (pH 8 ? 3, 9 ? 0) values. Requirement for and tolerance to NaCl were determined by observing growth on CLED agar (Difco) supplemented with 0–22 % NaCl. Strain 37 T required NaCl for growth, showing no growth at 0 % NaCl. It grew well at 1–12 % NaCl, and weak growth was observed at NaCl concentrations as high as 20 %. The ability of strain 37 to use a particular substrate as its sole carbon source was tested at substrate concentrations of 0 ? 2 % in SWC m in microtitre plate wells. Strain 37 T was inoculated in triplicate and incubated for 21 days at 5 u C. Growth was determined by measuring the absorbance at 600 nm using a DeltaSoft II microplate reader. Strain 37 T was able to use a wide variety of carbon sources, as detailed in the species description later. Sugar fermentation was tested using the Hugh–Leifson method (Gerhardt et al. , 1981). BBL brand OF basal medium was dissolved in ONR- 7a salt solution (Dyksterhouse et al. , 1995). Each carbon source was diluted to a concentration of 1 %. Vibrio splendi- dus and inoculated medium without added carbon source were used as positive and negative controls, respectively. Gas production from glucose metabolism was detected by growing strain 37 T in liquid SWC m supplemented with glucose into which Durham tubes were placed for gas detection. Strain 37 T was facultatively anaerobic and fermented several carbon sources, including lactose, sucrose, D -mannitol, salicin, maltose, trehalose, cellobiose, D -galactose, melibiose and D -glucose (without gas production), but not dulcitol, myo -inositol, D -sorbitol, L -arabinose or D -xylose. Requirement The The Biochemical The pH ability range range of of tests for for temperatures strain and growth were 37 tolerance performed was to use allowing tested to a NaCl particular using using growth were standard SWC substrate determined of m buffered strain methodo- as 37 by its to observing sole was logy various determined (Gerhardt carbon pH growth values source et by al. on observation with , was 1981). CLED 25 tested agar For mM of at these (Difco) solutions growth substrate tests, supplemented on cultures of SWC concentrations the m following of plates strain with at 0–22 of 37 5, buffers: T 0 10, ? were 2 % % 15 NaCl. MES, in grown and SWC Strain 20 pH m in u C in 5 SWC 37 ? for 7; microtitre T required ACES, m 8 days. supplemented pH plate NaCl Growth 6 ? wells. 6; for TAPSO, at growth, with Strain subzero the showing pH 37 appro- T tem- 7 was ? 4; priate inoculated peratures no TAPS, growth substrates. pH was 8 at in ? 3; also 0 triplicate CHES, % For tested NaCl. nitrate pH and using It 9 grew ? reduction, incubated 0) liquid (Dyksterhouse well SWC at strains for 1–12 m 21 . Strain % days were et NaCl, al. 37 , supple- at 1995). T 5 and was u C. Growth mented psychrophilic, weak Growth growth at with was each was determined 0 ? growing ...
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... from a sea ice core from Point Barrow, Alaska, USA, could grow at subfreezing temperatures, with a generation time of 240 h at 2 12 u C, the lowest recorded growth temperature of any organism verified by a growth curve (Breezee et al. , 2004). Strain 37 T was considered to represent a novel species, which was provisionally named Psychromonas ingrahamii sp. nov. It is most similar to Psychromonas antarctica and other members of the genus Psychromonas , a group of psychrophiles having a wide variety of physiological characteristics including piezophily, facultative psychrophily and halophily (Breezee et al. , 2004; Mountfort et al. , 1998; Kawasaki et al. , 2002; Nogi et al. , 2002; Xu et al. , 2003; Groudieva et al. , 2003; Ivanova et al. , 2004). Here we report additional information for this sea ice isolate to justify recognition of this novel species. Strain 37 was isolated in May 1991 from Elson Lagoon (Point Barrow, Alaska) about 130 cm from the ice–water interface of a 1 ? 8 m ice core (Gosink et al. , 1993). Ordal’s sea water cytophaga medium (SWC m ) prepared in full-strength artificial sea water (ASW) was used for the isolation and routine growth of strain 37 T (Irgens et al. , 1989). Colonies on plates were white, circular, smooth and convex, with an entire margin. Phenotypic characteristics of strain 37 T are summarized in Table 1. Recently, nutrient-rich Cell Strain size, 37 shape we was reported SIMCO and isolated the presence that band in May a (Gosink bacterial of 1991 gas vacuoles from et isolate, al. Elson , 1993). were designated Lagoon deter- Gas strain vacuoles (Point mined 37 for Barrow, T contain , cells isolated grown Alaska) small, from in rigid, about a Difco sea proteinaceous ice 130 marine core cm from broth from subunit Point the 2216 ice–water Barrow, (Becton vesicles Alaska, that interface Dickinson) are USA, gas-permeable, of a via 1 could ? 8 phase m grow ice core contrast reducing at subfreezing (Gosink microscopy cell et al. density temperatures, , 1993). using as Ordal’s compared a with Zeiss sea a water generation with Photomicroscope cytophaga the cytoplasm, time medium of I. Electron 240 and h (SWC at thereby micrographs 2 m 12 ) prepared u C, providing the were lowest in full-strength obtained buoyancy recorded of (Walsby, growth artificial unstained temperature sea 1972). whole water Gas cells (ASW) of vesicles by any using was organism act a used Zeiss as organelles for verified EM900 the isolation transmission by of a motility, growth and regulating curve routine electron (Breezee growth microscope the vertical et of al. strain , at 2004). movement 37 50 T kV. (Irgens Strain Cells of 37 cells et T of al. was via , strain 1989). their considered 37 synthesis Colonies T were to and on represent unusually plates degradation were a large, novel white, (Staley, ranging species, circular, 1980). from which smooth 6 Although to was 14 provisionally and m m gas convex, long vacuolate by with 1 named ? 25 bac- an to 1 teria entire Psychromonas ? 5 m m in margin. wide polar (Fig. 1; ingrahamii Phenotypic sea ice Breezee are sp. characteristics prevalent et al. nov. , 2004), It and is and of most phylogenetically were strain similar arranged 37 T are to diverse, singly, Psychromonas summarized in belonging pairs in antarctica or Table 1. in to short the and Alpha chains. other -, Motility Beta members - and was Gammaproteo- of examined the genus by bacteria incubation Psychromonas and of to , strain a the group Bacteroidetes 37 of T in psychrophiles liquid (Gosink SWC having m & Staley, for 12 a wide 1995), days vari- with the function periodic ety of physiological examination of gas vacuoles characteristics by phase in this contrast environment including microscopy, piezophily, remains and unknown. cells facultative were found psychrophily to be non-motile. and halophily Gas (Breezee vacuoles et were al. , 2004; also visible, Mountfort appearing et al. , 1998; as bright, Kawasaki refractive et al. , 2002; areas Nogi inside et cells al. , (Fig. 1). 2002; Xu Electron et al. , 2003; microscopy Groudieva revealed et al. , 2003; two Ivanova distinct et mor- al. , phologies 2004). Here of we gas report vacuoles: additional numerous information short, wide for cylinders this sea with ice isolate conical to tips; justify and recognition rare, longer of this but novel narrower species. cylinders with conical ends (Fig. 1b). The presence of two gas vacuole types is unusual, having been reported before only in the halophilic archaeon Halobacterium halobium (Walsby, 1994). Cell size, shape and the presence of gas vacuoles were determined for cells grown in Difco marine broth 2216 (Becton Dickinson) via phase contrast microscopy using a Zeiss Photomicroscope I. Electron micrographs were obtained of unstained whole cells by using a Zeiss EM900 transmission electron microscope at 50 kV. Cells of strain 37 T were unusually large, ranging from 6 to 14 m m long by 1 ? 25 to 1 ? 5 m m wide (Fig. 1; Breezee et al. , 2004), and were arranged singly, in pairs or in short chains. Motility was examined by incubation of strain 37 T in liquid SWC m for 12 days with periodic examination by phase contrast microscopy, and cells were found to be non-motile. Gas vacuoles were also visible, appearing as bright, refractive areas inside cells (Fig. 1). Electron microscopy revealed two distinct morphologies of gas vacuoles: numerous short, wide cylinders with conical tips; and rare, longer but narrower cylinders with conical ends (Fig. 1b). The presence of two gas vacuole types is unusual, having been reported before only in the halophilic archaeon Halobacterium halobium (Walsby, 1994). The pH range for growth was tested using SWC m buffered to various pH values with 25 mM solutions of the following buffers: MES, pH 5 ? 7; ACES, pH 6 ? 6; TAPSO, pH 7 ? 4; TAPS, pH 8 ? 3; CHES, pH 9 ? 0) (Dyksterhouse et al. , 1995). Growth at each pH was determined turbidometrically using a Bausch and Lomb 20-D spectrophotometer at 600 nm. Growth was observed at near neutral pH values (pH 6 ? 5, 6 ? 8 and 7 ? 4), but not at moderately acidic (pH 5 ? 0) or basic (pH 8 ? 3, 9 ? 0) values. Requirement for and tolerance to NaCl were determined by observing growth on CLED agar (Difco) supplemented with 0–22 % NaCl. Strain 37 T required NaCl for growth, showing no growth at 0 % NaCl. It grew well at 1–12 % NaCl, and weak growth was observed at NaCl concentrations as high as 20 %. The ability of strain 37 to use a particular substrate as its sole carbon source was tested at substrate concentrations of 0 ? 2 % in SWC m in microtitre plate wells. Strain 37 T was inoculated in triplicate and incubated for 21 days at 5 u C. Growth was determined by measuring the absorbance at 600 nm using a DeltaSoft II microplate reader. Strain 37 T was able to use a wide variety of carbon sources, as detailed in the species description later. Sugar fermentation was tested using the Hugh–Leifson method (Gerhardt et al. , 1981). BBL brand OF basal medium was dissolved in ONR- 7a salt solution (Dyksterhouse et al. , 1995). Each carbon source was diluted to a concentration of 1 %. Vibrio splendi- dus and inoculated medium without added carbon source were used as positive and negative controls, respectively. Gas production from glucose metabolism was detected by growing strain 37 T in liquid SWC m supplemented with glucose into which Durham tubes were placed for gas detection. Strain 37 T was facultatively anaerobic and fermented several carbon sources, including lactose, sucrose, D -mannitol, salicin, maltose, trehalose, cellobiose, D -galactose, melibiose and D -glucose (without gas production), but not dulcitol, myo -inositol, D -sorbitol, L -arabinose or D -xylose. Requirement The The Biochemical The pH ability range range of of tests for for temperatures strain and growth were 37 tolerance performed was to use allowing tested to a NaCl particular using using growth were standard SWC substrate determined of m buffered strain methodo- as 37 by its to observing sole was logy various determined (Gerhardt carbon pH growth values source et by al. on observation with , was 1981). CLED 25 tested agar For mM of at these (Difco) solutions growth substrate tests, supplemented on cultures of SWC concentrations the m following of plates strain with at 0–22 of 37 5, buffers: T 0 10, ? were 2 % % 15 NaCl. MES, in grown and SWC Strain 20 pH m in u C in 5 SWC 37 ? for 7; microtitre T required ACES, m 8 days. supplemented pH plate NaCl Growth 6 ? wells. 6; for TAPSO, at growth, with Strain subzero the showing pH 37 appro- T tem- 7 was ? 4; priate inoculated peratures no TAPS, growth substrates. pH was 8 at in ? 3; also 0 triplicate CHES, % For tested NaCl. nitrate pH and using It 9 grew ? reduction, incubated 0) liquid (Dyksterhouse well SWC at strains for 1–12 m 21 . Strain % days were et NaCl, al. 37 , supple- at 1995). T 5 and was u C. Growth mented psychrophilic, weak Growth growth at with was each was determined 0 ? growing 1 pH observed or was 0 ? 01 determined at % by temperatures at NaNO NaCl measuring concentrations 3 turbidometrically and from the 0 ? 17 absorbance % 2 12 agar. as to high using 10 Cells u as at C a of 20 600 with Bausch strain %. nm a generation using 37 and T were a Lomb DeltaSoft time Gram-negative, 20-D of 240 II spectrophotometer microplate h at oxidase-positive, 2 12 u reader. C (Breezee at Strain 600 weakly et nm. 37 al. T , Growth was catalase-positive 2004). able No was to growth use observed a and wide was positive at variety observed near neutral for of at carbon nitrate 15 pH u C. values sources, reduction, Attempts (pH as all detailed to 6 ? 5, traits grow 6 ? 8 and in characteristic strain the 7 ? 37 4), species T but at 2 not of 15 description u members C at were moderately unsuccessful later. of the acidic Sugar genus because (pH fermentation Psychromonas 5 ? 0) the or culture basic was . (pH tested medium 8 ? using 3, ...
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... (Maykut, 1985; Parkinson & Gloersen, 1993; Weeks & Ackley, 1982). Polar sea ice is seasonably variable and its formation begins during polar winter as the ocean surface waters freeze, forming a surface slush termed ‘frazil ice’. This ice consolidates into circular sheets of ‘pancake ice’, which become colonized by microbes that eventually establish the sea ice microbial community (SIMCO) (Nichol & Allison, 1997; Staley & Gosink, 1999; Garrison et al. , 1983). Polar sea ice is semisolid, containing channels of brine formed during ice crystallization. Brine pockets may reach salinity levels of 150 % (Maykut, 1985), providing a liquid-phase environment at subzero temperatures. Sea ice is an active environment with large gradients in light, temperature, nutrient availability and salinity, all of which change seasonally (Eicken, 1992). The SIMCOs are typically concentrated in the lower 10–20 cm of a sea ice column, at the ice–water interface, where both sufficient nutrients from the water column and sufficient surface light are present (Staley & Gosink, 1999). The SIMCOs are stratified, containing large varieties of both eukaryotes and prokaryotes. Recent attempts to characterize the bacterial component of SIMCOs have revealed great diversity. To our knowledge, six new genera of the phylum Bacteroidetes (Gosink et al. , 1998; Bowman et al. , 1998a, 1997, 2003; Bowman & Nichols, 2002) and three new genera of Proteo- bacteria (Gosink et al. , 1997; Irgens et al. , 1996; Bowman et al. , 1998b) have been identified within or near the SIMCO, along with known Gram-positive genera (Junge et al. , 1998). Among the SIMCOs, gas vacuolate heterotrophs have been discovered in high numbers from both the Arctic and the Antarctic (Gosink et al. , 1993; Staley et al. , 1989), located either in the water column below or in the ice above the Recently, we reported that a bacterial isolate, designated strain 37 T , isolated from a sea ice core from Point Barrow, Alaska, USA, could grow at subfreezing temperatures, with a generation time of 240 h at 2 12 u C, the lowest recorded growth temperature of any organism verified by a growth curve (Breezee et al. , 2004). Strain 37 T was considered to represent a novel species, which was provisionally named Psychromonas ingrahamii sp. nov. It is most similar to Psychromonas antarctica and other members of the genus Psychromonas , a group of psychrophiles having a wide variety of physiological characteristics including piezophily, facultative psychrophily and halophily (Breezee et al. , 2004; Mountfort et al. , 1998; Kawasaki et al. , 2002; Nogi et al. , 2002; Xu et al. , 2003; Groudieva et al. , 2003; Ivanova et al. , 2004). Here we report additional information for this sea ice isolate to justify recognition of this novel species. Strain 37 was isolated in May 1991 from Elson Lagoon (Point Barrow, Alaska) about 130 cm from the ice–water interface of a 1 ? 8 m ice core (Gosink et al. , 1993). Ordal’s sea water cytophaga medium (SWC m ) prepared in full-strength artificial sea water (ASW) was used for the isolation and routine growth of strain 37 T (Irgens et al. , 1989). Colonies on plates were white, circular, smooth and convex, with an entire margin. Phenotypic characteristics of strain 37 T are summarized in Table 1. Recently, nutrient-rich Cell Strain size, 37 shape we was reported SIMCO and isolated the presence that band in May a (Gosink bacterial of 1991 gas vacuoles from et isolate, al. Elson , 1993). were designated Lagoon deter- Gas strain vacuoles (Point mined 37 for Barrow, T contain , cells isolated grown Alaska) small, from in rigid, about a Difco sea proteinaceous ice 130 marine core cm from broth from subunit Point the 2216 ice–water Barrow, (Becton vesicles Alaska, that interface Dickinson) are USA, gas-permeable, of a via 1 could ? 8 phase m grow ice core contrast reducing at subfreezing (Gosink microscopy cell et al. density temperatures, , 1993). using as Ordal’s compared a with Zeiss sea a water generation with Photomicroscope cytophaga the cytoplasm, time medium of I. Electron 240 and h (SWC at thereby micrographs 2 m 12 ) prepared u C, providing the were lowest in full-strength obtained buoyancy recorded of (Walsby, growth artificial unstained temperature sea 1972). whole water Gas cells (ASW) of vesicles by any using was organism act a used Zeiss as organelles for verified EM900 the isolation transmission by of a motility, growth and regulating curve routine electron (Breezee growth microscope the vertical et of al. strain , at 2004). movement 37 50 T kV. (Irgens Strain Cells of 37 cells et T of al. was via , strain 1989). their considered 37 synthesis Colonies T were to and on represent unusually plates degradation were a large, novel white, (Staley, ranging species, circular, 1980). from which smooth 6 Although to was 14 provisionally and m m gas convex, long vacuolate by with 1 named ? 25 bac- an to 1 teria entire Psychromonas ? 5 m m in margin. wide polar (Fig. 1; ingrahamii Phenotypic sea ice Breezee are sp. characteristics prevalent et al. nov. , 2004), It and is and of most phylogenetically were strain similar arranged 37 T are to diverse, singly, Psychromonas summarized in belonging pairs in antarctica or Table 1. in to short the and Alpha chains. other -, Motility Beta members - and was Gammaproteo- of examined the genus by bacteria incubation Psychromonas and of to , strain a the group Bacteroidetes 37 of T in psychrophiles liquid (Gosink SWC having m & Staley, for 12 a wide 1995), days vari- with the function periodic ety of physiological examination of gas vacuoles characteristics by phase in this contrast environment including microscopy, piezophily, remains and unknown. cells facultative were found psychrophily to be non-motile. and halophily Gas (Breezee vacuoles et were al. , 2004; also visible, Mountfort appearing et al. , 1998; as bright, Kawasaki refractive et al. , 2002; areas Nogi inside et cells al. , (Fig. 1). 2002; Xu Electron et al. , 2003; microscopy Groudieva revealed et al. , 2003; two Ivanova distinct et mor- al. , phologies 2004). Here of we gas report vacuoles: additional numerous information short, wide for cylinders this sea with ice isolate conical to tips; justify and recognition rare, longer of this but novel narrower species. cylinders with conical ends (Fig. 1b). The presence of two gas vacuole types is unusual, having been reported before only in the halophilic archaeon Halobacterium halobium (Walsby, 1994). Cell size, shape and the presence of gas vacuoles were determined for cells grown in Difco marine broth 2216 (Becton Dickinson) via phase contrast microscopy using a Zeiss Photomicroscope I. Electron micrographs were obtained of unstained whole cells by using a Zeiss EM900 transmission electron microscope at 50 kV. Cells of strain 37 T were unusually large, ranging from 6 to 14 m m long by 1 ? 25 to 1 ? 5 m m wide (Fig. 1; Breezee et al. , 2004), and were arranged singly, in pairs or in short chains. Motility was examined by incubation of strain 37 T in liquid SWC m for 12 days with periodic examination by phase contrast microscopy, and cells were found to be non-motile. Gas vacuoles were also visible, appearing as bright, refractive areas inside cells (Fig. 1). Electron microscopy revealed two distinct morphologies of gas vacuoles: numerous short, wide cylinders with conical tips; and rare, longer but narrower cylinders with conical ends (Fig. 1b). The presence of two gas vacuole types is unusual, having been reported before only in the halophilic archaeon Halobacterium halobium (Walsby, 1994). The pH range for growth was tested using SWC m buffered to various pH values with 25 mM solutions of the following buffers: MES, pH 5 ? 7; ACES, pH 6 ? 6; TAPSO, pH 7 ? 4; TAPS, pH 8 ? 3; CHES, pH 9 ? 0) (Dyksterhouse et al. , 1995). Growth at each pH was determined turbidometrically using a Bausch and Lomb 20-D spectrophotometer at 600 nm. Growth was observed at near neutral pH values (pH 6 ? 5, 6 ? 8 and 7 ? 4), but not at moderately acidic (pH 5 ? 0) or basic (pH 8 ? 3, 9 ? 0) values. Requirement for and tolerance to NaCl were determined by observing growth on CLED agar (Difco) supplemented with 0–22 % NaCl. Strain 37 T required NaCl for growth, showing no growth at 0 % NaCl. It grew well at 1–12 % NaCl, and weak growth was observed at NaCl concentrations as high as 20 %. The ability of strain 37 to use a particular substrate as its sole carbon source was tested at substrate concentrations of 0 ? 2 % in SWC m in microtitre plate wells. Strain 37 T was inoculated in triplicate and incubated for 21 days at 5 u C. Growth was determined by measuring the absorbance at 600 nm using a DeltaSoft II microplate reader. Strain 37 T was able to use a wide variety of carbon sources, as detailed in the species description later. Sugar fermentation was tested using the Hugh–Leifson method (Gerhardt et al. , 1981). BBL brand OF basal medium was dissolved in ONR- 7a salt solution (Dyksterhouse et al. , 1995). Each carbon source was diluted to a concentration of 1 %. Vibrio splendi- dus and inoculated medium without added carbon source were used as positive and negative controls, respectively. Gas production from glucose metabolism was detected by growing strain 37 T in liquid SWC m supplemented with glucose into which Durham tubes were placed for gas detection. Strain 37 T was facultatively anaerobic and fermented several carbon sources, including lactose, sucrose, D -mannitol, salicin, maltose, trehalose, cellobiose, D -galactose, melibiose and D -glucose (without gas production), but not dulcitol, myo -inositol, D -sorbitol, L -arabinose or D -xylose. Requirement The The Biochemical The pH ability range range of of tests for for temperatures strain and growth were 37 tolerance performed was to use allowing tested to a NaCl particular using using growth were standard SWC substrate determined of m buffered strain methodo- as 37 by its to ...
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... ingrahamii sp. nov. It is most similar to Psychromonas antarctica and other members of the genus Psychromonas , a group of psychrophiles having a wide variety of physiological characteristics including piezophily, facultative psychrophily and halophily (Breezee et al. , 2004; Mountfort et al. , 1998; Kawasaki et al. , 2002; Nogi et al. , 2002; Xu et al. , 2003; Groudieva et al. , 2003; Ivanova et al. , 2004). Here we report additional information for this sea ice isolate to justify recognition of this novel species. Strain 37 was isolated in May 1991 from Elson Lagoon (Point Barrow, Alaska) about 130 cm from the ice–water interface of a 1 ? 8 m ice core (Gosink et al. , 1993). Ordal’s sea water cytophaga medium (SWC m ) prepared in full-strength artificial sea water (ASW) was used for the isolation and routine growth of strain 37 T (Irgens et al. , 1989). Colonies on plates were white, circular, smooth and convex, with an entire margin. Phenotypic characteristics of strain 37 T are summarized in Table 1. Recently, nutrient-rich Cell Strain size, 37 shape we was reported SIMCO and isolated the presence that band in May a (Gosink bacterial of 1991 gas vacuoles from et isolate, al. Elson , 1993). were designated Lagoon deter- Gas strain vacuoles (Point mined 37 for Barrow, T contain , cells isolated grown Alaska) small, from in rigid, about a Difco sea proteinaceous ice 130 marine core cm from broth from subunit Point the 2216 ice–water Barrow, (Becton vesicles Alaska, that interface Dickinson) are USA, gas-permeable, of a via 1 could ? 8 phase m grow ice core contrast reducing at subfreezing (Gosink microscopy cell et al. density temperatures, , 1993). using as Ordal’s compared a with Zeiss sea a water generation with Photomicroscope cytophaga the cytoplasm, time medium of I. Electron 240 and h (SWC at thereby micrographs 2 m 12 ) prepared u C, providing the were lowest in full-strength obtained buoyancy recorded of (Walsby, growth artificial unstained temperature sea 1972). whole water Gas cells (ASW) of vesicles by any using was organism act a used Zeiss as organelles for verified EM900 the isolation transmission by of a motility, growth and regulating curve routine electron (Breezee growth microscope the vertical et of al. strain , at 2004). movement 37 50 T kV. (Irgens Strain Cells of 37 cells et T of al. was via , strain 1989). their considered 37 synthesis Colonies T were to and on represent unusually plates degradation were a large, novel white, (Staley, ranging species, circular, 1980). from which smooth 6 Although to was 14 provisionally and m m gas convex, long vacuolate by with 1 named ? 25 bac- an to 1 teria entire Psychromonas ? 5 m m in margin. wide polar (Fig. 1; ingrahamii Phenotypic sea ice Breezee are sp. characteristics prevalent et al. nov. , 2004), It and is and of most phylogenetically were strain similar arranged 37 T are to diverse, singly, Psychromonas summarized in belonging pairs in antarctica or Table 1. in to short the and Alpha chains. other -, Motility Beta members - and was Gammaproteo- of examined the genus by bacteria incubation Psychromonas and of to , strain a the group Bacteroidetes 37 of T in psychrophiles liquid (Gosink SWC having m & Staley, for 12 a wide 1995), days vari- with the function periodic ety of physiological examination of gas vacuoles characteristics by phase in this contrast environment including microscopy, piezophily, remains and unknown. cells facultative were found psychrophily to be non-motile. and halophily Gas (Breezee vacuoles et were al. , 2004; also visible, Mountfort appearing et al. , 1998; as bright, Kawasaki refractive et al. , 2002; areas Nogi inside et cells al. , (Fig. 1). 2002; Xu Electron et al. , 2003; microscopy Groudieva revealed et al. , 2003; two Ivanova distinct et mor- al. , phologies 2004). Here of we gas report vacuoles: additional numerous information short, wide for cylinders this sea with ice isolate conical to tips; justify and recognition rare, longer of this but novel narrower species. cylinders with conical ends (Fig. 1b). The presence of two gas vacuole types is unusual, having been reported before only in the halophilic archaeon Halobacterium halobium (Walsby, 1994). Cell size, shape and the presence of gas vacuoles were determined for cells grown in Difco marine broth 2216 (Becton Dickinson) via phase contrast microscopy using a Zeiss Photomicroscope I. Electron micrographs were obtained of unstained whole cells by using a Zeiss EM900 transmission electron microscope at 50 kV. Cells of strain 37 T were unusually large, ranging from 6 to 14 m m long by 1 ? 25 to 1 ? 5 m m wide (Fig. 1; Breezee et al. , 2004), and were arranged singly, in pairs or in short chains. Motility was examined by incubation of strain 37 T in liquid SWC m for 12 days with periodic examination by phase contrast microscopy, and cells were found to be non-motile. Gas vacuoles were also visible, appearing as bright, refractive areas inside cells (Fig. 1). Electron microscopy revealed two distinct morphologies of gas vacuoles: numerous short, wide cylinders with conical tips; and rare, longer but narrower cylinders with conical ends (Fig. 1b). The presence of two gas vacuole types is unusual, having been reported before only in the halophilic archaeon Halobacterium halobium (Walsby, 1994). The pH range for growth was tested using SWC m buffered to various pH values with 25 mM solutions of the following buffers: MES, pH 5 ? 7; ACES, pH 6 ? 6; TAPSO, pH 7 ? 4; TAPS, pH 8 ? 3; CHES, pH 9 ? 0) (Dyksterhouse et al. , 1995). Growth at each pH was determined turbidometrically using a Bausch and Lomb 20-D spectrophotometer at 600 nm. Growth was observed at near neutral pH values (pH 6 ? 5, 6 ? 8 and 7 ? 4), but not at moderately acidic (pH 5 ? 0) or basic (pH 8 ? 3, 9 ? 0) values. Requirement for and tolerance to NaCl were determined by observing growth on CLED agar (Difco) supplemented with 0–22 % NaCl. Strain 37 T required NaCl for growth, showing no growth at 0 % NaCl. It grew well at 1–12 % NaCl, and weak growth was observed at NaCl concentrations as high as 20 %. The ability of strain 37 to use a particular substrate as its sole carbon source was tested at substrate concentrations of 0 ? 2 % in SWC m in microtitre plate wells. Strain 37 T was inoculated in triplicate and incubated for 21 days at 5 u C. Growth was determined by measuring the absorbance at 600 nm using a DeltaSoft II microplate reader. Strain 37 T was able to use a wide variety of carbon sources, as detailed in the species description later. Sugar fermentation was tested using the Hugh–Leifson method (Gerhardt et al. , 1981). BBL brand OF basal medium was dissolved in ONR- 7a salt solution (Dyksterhouse et al. , 1995). Each carbon source was diluted to a concentration of 1 %. Vibrio splendi- dus and inoculated medium without added carbon source were used as positive and negative controls, respectively. Gas production from glucose metabolism was detected by growing strain 37 T in liquid SWC m supplemented with glucose into which Durham tubes were placed for gas detection. Strain 37 T was facultatively anaerobic and fermented several carbon sources, including lactose, sucrose, D -mannitol, salicin, maltose, trehalose, cellobiose, D -galactose, melibiose and D -glucose (without gas production), but not dulcitol, myo -inositol, D -sorbitol, L -arabinose or D -xylose. Requirement The The Biochemical The pH ability range range of of tests for for temperatures strain and growth were 37 tolerance performed was to use allowing tested to a NaCl particular using using growth were standard SWC substrate determined of m buffered strain methodo- as 37 by its to observing sole was logy various determined (Gerhardt carbon pH growth values source et by al. on observation with , was 1981). CLED 25 tested agar For mM of at these (Difco) solutions growth substrate tests, supplemented on cultures of SWC concentrations the m following of plates strain with at 0–22 of 37 5, buffers: T 0 10, ? were 2 % % 15 NaCl. MES, in grown and SWC Strain 20 pH m in u C in 5 SWC 37 ? for 7; microtitre T required ACES, m 8 days. supplemented pH plate NaCl Growth 6 ? wells. 6; for TAPSO, at growth, with Strain subzero the showing pH 37 appro- T tem- 7 was ? 4; priate inoculated peratures no TAPS, growth substrates. pH was 8 at in ? 3; also 0 triplicate CHES, % For tested NaCl. nitrate pH and using It 9 grew ? reduction, incubated 0) liquid (Dyksterhouse well SWC at strains for 1–12 m 21 . Strain % days were et NaCl, al. 37 , supple- at 1995). T 5 and was u C. Growth mented psychrophilic, weak Growth growth at with was each was determined 0 ? growing 1 pH observed or was 0 ? 01 determined at % by temperatures at NaNO NaCl measuring concentrations 3 turbidometrically and from the 0 ? 17 absorbance % 2 12 agar. as to high using 10 Cells u as at C a of 20 600 with Bausch strain %. nm a generation using 37 and T were a Lomb DeltaSoft time Gram-negative, 20-D of 240 II spectrophotometer microplate h at oxidase-positive, 2 12 u reader. C (Breezee at Strain 600 weakly et nm. 37 al. T , Growth was catalase-positive 2004). able No was to growth use observed a and wide was positive at variety observed near neutral for of at carbon nitrate 15 pH u C. values sources, reduction, Attempts (pH as all detailed to 6 ? 5, traits grow 6 ? 8 and in characteristic strain the 7 ? 37 4), species T but at 2 not of 15 description u members C at were moderately unsuccessful later. of the acidic Sugar genus because (pH fermentation Psychromonas 5 ? 0) the or culture basic was . (pH tested medium 8 ? using 3, routinely 9 ? 0) the values. Hugh–Leifson froze. The true method minimum (Gerhardt growth et tem- al. , 1981). perature BBL may brand in fact OF be basal lower medium than 2 was 12 u dissolved C. in ONR- 7a salt solution (Dyksterhouse et al. , 1995). Each carbon source was diluted to a concentration of 1 %. Vibrio splendi- dus and inoculated ...
Citations
... Most of the psychrophilic extremophiles are piezo-philes too and commonly belong to Gammaproteobacteria, and the predominant genera are Psychromonas, Moritella, Colwellia, Photobacterium, Shewanella, and Arthrobacter as shown in Fig. 5.2 and Table 5.1 (Fang et al., 2010;Bell et al., 2013;Qin et al., 2014). Antarctic soil sources were also explored for the isolation and identification of extremophiles by using NGS tools (Auman et al., 2006;Tytgat et al., 2014;Ji et al., 2016). Bacterial, archaeal, and fungal diversity from the extreme cold conditions were extensively studied through metagenomic analysis (Kochkina et al., 2012;Ji et al., 2016). ...
Extreme environments of Earth are colonized with microbial communities that have the ability to survive under diverse extreme conditions, such as salinity, acidity, alkalinity, high and low temperatures, high pressure, and radiations. Extremophiles have special genetic and physiological modifications to function properly under extreme environments. They possess extremozymes and other biomolecules that can be used in various industrial processes, for example, pharmaceuticals, paper manufacturing, degradation of complex organic molecules, biofuel production, and food industries. With the advent of new sequencing technologies and “omics” approaches, such as metagenomics, metatranscriptomics, and metaproteomics, new windows have been opened to study the structure and composition of microbial communities from various extreme environments. Recently, metagenomic analyses of extreme environments have shown the abundance of novel microorganisms representing a majority of previously unexplored phylogenetic and functional diversity of unculturable extremophiles. In this chapter, we focus on the recent research on microbial communities in extreme environments, their adaptive strategies, and biological functions.
... As psychrophilic DNA polymerase is unavailable commercially, we set out to recombinantly purify one for our study. Based on homology search, we identified DNA polymerase I (PIPI; IMG Gene ID: 639798289), a family A polymerase, from Psychromonas ingrahamii,a gram-negative bacteria that can grow and replicate at -12 o C in laboratory condition [31][32][33] . MBP-PIPI was purified by maltose affinity column, cleaved off its tandem-fused MBP tag, and then re-purified with size exclusion chromatography (Methods) (Supplemental Figure 1a). ...
The discovery of extremophiles helped enable the development of groundbreaking technology such as polymerase chain reaction. Temperature variation is often an essential step of these technology platforms, but the effect of temperature on the error rate of polymerases from different origins is under-explored. Here, we applied high-throughput sequencing to profile the error rates of DNA polymerases from psychrophilic, mesophilic, and thermophilic origins with single-molecule resolution. We found that reaction temperature substantially increases substitution and deletion error rates of psychrophilic and mesophilic DNA polymerases. Our motif analysis shows that the substitution error profiles cluster according to phylogenetic similarity of polymerases, not reaction temperature, thus suggesting that reaction temperature increases global error rate of polymerases independent of sequence context. Intriguingly, we also found that the DNA polymerase I of a psychrophilic bacteria exhibits higher polymerization activity than its mesophilic ortholog across all temperature ranges, including down to -19oC which is well below the freezing temperature of water. Our results provide a useful reference for how reaction temperature, a crucial parameter of biochemistry, can affect DNA polymerase fidelity in organisms adapted to a wide range of thermal environments.
... To cope with such stress conditions, these microorganisms exhibit numerous adaptive strategies such as the production of antifreeze protein, cold-active enzymes, exopolysaccharides, unsaturated fatty acids, ice-nucleating protein and pigments (Margesin and Miteva 2011;Sakamoto and Murata 2002;Stibal et al. 2008). Cold tolerant bacterial strains reported from several habitats belongs to phyla Proteobacteria (Auman et al. 2006;Huston et al. 2000), Firmicutes (Junge et al. 2011;Yoon et al. 2001) and Bacteroidetes (Mc Cammon and Bowman 2000). Microorganisms reported from polar and nonpolar ecosystems are dominated by phylum Actinobacteria, Cyanobacteria, Proteobacteria, Bacteroidetes, and Firmicutes. ...
High-throughput sequencing approach of the 16S rRNA gene was employed to evaluate the bacterial diversity inhabit in melted water, snow, soil, and rocks samples at the lower altitudes of the Laohugou glacial environment. Bioinformatics tools were used to process millions of Illumina reads for alpha and beta diversities of bacterial communities. The diversity indices such as Chao, Shannon, and Simpson were different in the collected samples and solid samples (soil and rocks) showed higher taxon richness and evenness. Taxonomic diversity was unexpectedly higher and the major portion of sequences was assigned to Proteobacteria, Actinobacteria, and Acidobacteria. Higher variation in community structure was reported at the class level and Alphaproteobacteria was dominant. The solid niches were occupied by a higher number of phyla compared with liquid. The physicochemical variables acted as spatial gradients and associated with the bacterial structural communities of the glacial ecosystem. Findings showed that both Proteobacteria and Actinobacteria in solid samples influenced the bacterial community structure in downstream liquid samples. Interestingly, the metagenomic biomarkers were higher in liquid samples. This study provides precious datasets to understand the bacterial community in a better way under the influence of spatial, physical and environmental factors.
... To better understand the effect of temperature-adaptation on polymerase fidelity, we characterized replication error rates of psychrophilic, mesophilic, and thermophilic DNA polymerases across a wide range of reaction temperatures. As no commercial source was available for psychrophilic DNA polymerases, we determined the coding sequences bioinformatically, and optimized a recombinant cloning and purification strategy for DNA Figure 1a) (Methods) [27][28][29] . We named the DNA polymerases I and II from this psychrophilic bacteria as Psychromonas ingrahamii polymerase I (PIPI) and Psychromonas ingrahamii polymerase B (PIPB), respectively. ...
The discovery of extremophiles has enabled development of groundbreaking biotechnology. While most of the extremophile research is focused on thermophiles, organisms that adapt to living in cold temperature, known as psychrophiles, remain under-studied. We expressed and purified DNA polymerases PIPI and PIPB from Psychromonas ingrahamii, a psychrophile that can grow below water's freezing temperature. We demonstrate that they have in vitro DNA replication activity at temperatures as low as -19oC. To our knowledge, this is the coolest DNA polymerization reaction ever carried out in a laboratory. In exploring the behavior of a variety of polymerases as a function of temperature, we found that reaction temperature substantially increases substitution and deletion error rates of both psychrophilic and mesophilic DNA polymerases. Motif analysis further reveals that the substitution error profiles cluster according to phylogenetic similarity of polymerases. Our results provide a useful reference for how reaction temperature, a crucial parameter of biochemistry, can affect the fidelity of DNA polymerases adapted to a wide range of environment.
... The data indicate that the predominant genera Psychromonas, Vibrio, Gaetbulibacter, and Psychroserpens could influence the treatment efficiency of eco-HEMS in winter. Especially, genus Psychromonas includes halophilic (high-salt adapted) and psychrophilic (low temperature adapted) species, which display various chemotrophic metabolic activities including nitrification and denitrification, and the synthesis of polyunsaturated fatty acids, such as eicosapentaenoic acid and docosahexaenoic acid [29][30][31]. ...
Effective biological treatment of marine wastewater is not well-known. Accumulation of nitrogen and phosphorus from land-based effluent is a crucial cause of red-tide in marine systems. The purpose of the study is to reduce nitrogen and phosphorus in marine wastewater with a pilot plant-scale sequencing batch reactor (SBR) system by using marine sediment as eco-friendly and effective biological materials, and elucidate which bacterial strains in sludge from marine sediment influence the performance of SBR. By applying eco-friendly high efficiency marine sludge (eco-HEMS), the treatment performance was 15 m³ d⁻¹ of treatment amount in 4.5 m³ of the reactor with the average removal efficiency of 89.3% for total nitrogen and 94.9% for total phosphorus at the optimal operation condition in summer. Moreover, the average removal efficiency was 84.0% for total nitrogen and 88.3% for total phosphorus in winter although biological treatment efficiency in winter is generally lower due to bacterial lower activity. These results were revealed by the DNA barcoding analysis of 16s rRNA amplicon sequencing of samples from the sludge in winter. The comparative analysis of the bacterial community composition in sludge at the high efficiency of the system showed the predominant genera Psychromonas (significantly increased to 45.6% relative abundance), Vibrio (13.3%), Gaetbulibacter (5.7%), and Psychroserpens (4.3%) in the 4 week adaptation after adding marine sediment, suggesting that those predominant bacteria influenced the treatment performance in winter.
... Wide variations of bacterial and archaeal diversity arereported in low temperature environmental conditions which can be psychrophilic or psychrotrophic, Gram-positive or Gram-negative, aerobic or anaerobic, autotrophic or heterotrophic, phototrophic or non-phototrophic (Zhu and Dittrich, 2016;Kusube et al., 2017). Taxonomically, these cold active species are distributed over different genera such as Arthrobacter, Colwellia, Exiguobacterium , Gelidibacter, Glaciecola (Bowman et al., 1998), Halobacillus, Halomonas (Reddy et al., 2003), Hyphomonas, Listeria (Lee et al., 2013), Marinobacter (Zhang et al., 2008), Methanococcoides, Methanogenium (Franzmann et al., 1997), Moritella (Kim et al., 2008), Planococcus (Mykytczuket al., 2013, Pseudoalteromonas, Pseudomonas (Reddy et al., 2004), Psychrobacter, Psychroflexus (Bowman et al., 1998), Psychromonas (Auman et al., 2006), Psychroserpens (Baek et al., 2015), Shewanella (Yang et al., 2007) and Sphingomonas (Poli et al., 2017). D' Amico et al. (2006) mentioned that the commonly reported microorganisms are the Gram-negative a-, band g-proteobacteria (Pseudomonas and Vibrio) and the Cytopha-gaeFlavobacteriumeBacteriodes phylum, whereas Coryneforms, Arthrobacter and Micrococcus species are the most frequently found Gram-positive bacteria. ...
Cold adapted bacteria undertake array of adaptive strategies and remain active with an active temperature range of 0–40 °C and activity in the acidic to neutral pH range (pH 4.5–7.0) to withstand in extreme environmental conditions and to retain metabolic and enzymatic activities. In soil, water or food, they were reported to comprise higher population as compared to mesophilic and thermophilic population (can make up to 86% of the total population). The present work critically discusses a detailed account of different strategies of cold adaptations in bacteria at cellular (viz. regulation of cell membrane fluidity through lipidcomposition, carotenoids production, cryoprotectants) and molecular level (differential gene expression, chaperones, proline isomerisation, antifreeze proteins, proteins and enzymes), cold-active cellulases from psychrophiles, their production strategies, the factors affecting and their properties and cold-active enzyme activities for different applications with special focus on cold-active cellulases. Due to more flexibility in protein structure and related higher binding capacity with the substrates, cold enzymes have more catalytic activities (around 10 times more than amesophilic enzyme) at cold temperatures. Attempt is made to critically analyze the practical relevance and significance of these aspects to help explore future directions of research related to scope of versatile applications of cold active enzyme.
... In most species of this family, the major respiratory quinone is Q-8 and the major fatty acids are C 16:0 and C 18:1 x7c. Members of the family have been isolated from coastal, open and deep-sea waters, ice, sediments and other marine environments (Auman et al. 2010;Groudieva et al. 2003;Auman et al. 2006). The G ? C contents of DNA range between 38.0 and 43.8 mol%. ...
A novel Gram-stain negative, strictly aerobic, rod-shaped motile bacterium with a single flagellum, designated strain DASS28T, was isolated from surface sediment of Bohai Sea in China. Growth occurred in the presence of 1.0–4.0% NaCl (w/v, optimum 2.0%), at 10–37 °C (optimum 20 °C) on the Marine agar 2216E and pH 6.0–10.0 (optimum pH 8.0). The major fatty acids (> 10% of total fatty acids) were summed feature 3 (C16:1ω7c and/or iso-C15:0 2-OH), C16:0 and C18:1ω7c. The polar lipids were phosphatidylglycerol, phosphatidylethanolamine, an unidentified phospholipid, an unidentified aminolipid and two unidentified polar lipids. The major respiratory quinone was ubiquinone-8 (Q-8). The genomic DNA G + C content calculated from the genome sequence of strain DASS28T was 48.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain DASS28T belongs to the genus Corallincola and shows high 16S rRNA gene sequence similarity of 96.7% to Corallincola platygyrae JLT 2006T (= JCM18796T = CGMCC 1.10992T). On the basis of the polyphasic evidence, strain DASS28T is considered to represent a novel species in the genus Corallincola, for which the name Corallincola luteus sp. nov. is proposed. The type strain is DASS28T (= KCTC 52376T = MCCC 1K03208T).
... The microbes which show minimum, optimum and maximum growth temperatures at or below 0 °C, 15 °C, and 20 °C are called psychrophiles (Morita 1975). Psychrophilic bacteria isolated from different habitats belong to phyla Proteobacteria, (Auman et al. 2006;Huston et al. 2000), Bacteroidetes (Mc Cammon and Bowman 2000) and Firimcutes (Junge et al. 2011;Yoon et al. 2001). Bacteria found in the upper layers of glaciers can be considered as a recent deposition events and show community diversity profile and relation to local environments. ...
Microbial communities at cryosphere are the cosmopolitan buffers of important biogeochemical processes stationed at extreme archaic and frigid conditions. In the present study microbial diversity analysis from accumulation zone of two glaciers of North Sikkim, India has been carried by two culture independent methods. The phospholipid fatty acids analysis of Changme Khang and Changme Khangpu glacier showed that both of these were dominated by Gram-positive bacteria followed by Gram-negative bacteria. Among the two glaciers, Changme Khang (54.04%) had higher percentage of Gram-positive bacteria than Changme Khangpu (24.84%), while Gram-negative bacteria were higher in Changme Khangpu (22.65%) than Changme Khang (4.41%). The metagenomic analysis shows the dominance of Proteobacteria followed by Firmicutes and Actinobacteria. Betaproteobacteria were the dominant class among Proteobacteria. Similar kind of bacterial diversity was also observed from other polar and non-polar glaciers.
... These membrane adaptations to cold include increases in unsaturated FAs, short chain FAs and branched chain FAs as well as the incorporation of carotenoids and glycolipids. Several studies have described the membrane lipid composition and adaptation to cold in psychrophilic bacteria (which have an optimum growth temperature of < 15 • C) including Clostridium psychrophilum, Colwellia psychrerythraea and Psychromonas ingrahamii (Breezee et al., 2004;Auman et al., 2006;Guan et al., 2013;Wan et al., 2016). Membrane adaptation to cold in psychrotolerant bacteria (which have an optimum temperature between 20 and 40 • C, but are also capable of growth around 0 • C) has been studied for species including Sphingobacterium antarcticus and Micrococcus roseus (Chattopadhyay et al., 1997;Jagannadham et al., 2000). ...
Three strains of aerobic psychrotolerant methanotrophic bacteria Methylovulum psychrotolerans, isolated from geographically remote low-temperature environments in Northern Russia, were grown at three different growth temperatures, 20, 10 and 4°C and were found to be capable of oxidizing methane at all temperatures. The three M. psychrotolerans strains adapted their membranes to decreasing growth temperature by increasing the percent of unsaturated fatty acid (FAs), both for the bulk and intact polar lipid (IPL)-bound FAs. Furthermore, the ratio of βOH-C16:0 to n-C16:0 increased as growth temperature decreased. The IPL head group composition did not change as an adaption to temperature. The most notable hopanoid temperature adaptation of M. psychrotolerans was an increase in unsaturated hopanols with decreasing temperature. As the growth temperature decreased from 20 to 4°C, the percent of unsaturated M. psychrotolerans bulk-FAs increased from 79 to 89 % while the total percent of unsaturated hopanoids increased from 27 to 49 %. While increased FA unsaturation in response to decreased temperature is a commonly observed response in order to maintain the liquid-crystalline character of bacterial membranes, hopanoid unsaturation upon cold exposition has not previously been described. In order to investigate the mechanisms of both FA and hopanoid cold-adaption in M. psychrotolerans we identified genes in the genome of M. psychrotolerans that potentially code for FA and hopanoid desaturases. The unsaturation of hopanoids represents a novel membrane adaption to maintain homeostasis upon cold adaptation.
... The bacterium lives in a neutral habitat with optimal pH range from 6.5 to 7.4, sodium chloride concentrations of 1 to 10%, and at temperatures of − 12 to 10 °C. The optimal growth temperature is 5 °C with no growth observed above 15 °C [20]. P. ingrahamii was also shown to be able to proliferate at − 12 °C, which is the lowest temperature noted for any organism [19]. ...
... The genome of P. ingrahamii is approximately 4.5 Mb and the G+C content reaches 40% [21]. The phylogenetic analysis of the 16S rRNA gene sequence shows that the bacterium is closely related to the psychromonas type [20]. ...
Nucleases are an important group of hydrolases that degrade nucleic acids, with broad spectrum of applications in science and industry. In this paper, we report the identification and characterization of the nuclease from extremely psychrophilic bacterium Psychromonas ingrahamii that grows exponentially at 5 °C, but may also grow at even lower temperatures (down to − 12 °C). The putative endonuclease I gene, identified in the genome of P. ingrahamii, was cloned and expressed in Pichia pastoris. The recombinant protein was purified and its nucleolytic features were studied. The new enzyme, named by us as PinNuc, displays the features characteristic for the nonselective endonucleases, and has the ability to degrade different forms of nucleic acids. It is very active at room temperature in low ion-strength buffer and in the presence of low concentrations of magnesium ions. The enzyme, which possesses six cysteine residues, the most likely all engaged in disulphide bridges, is active only in oxidized form, and can be efficiently inactivated by the addition of low amounts of a reducing agent. According to our knowledge, it is the first nuclease, belonging to endonuclease I family, isolated from such extremely psychrophilic organism.
