的6 odtoodae them Thermus thermophils(strain HB8)was found in 2005 to The structures of the components of the acid di-myinphosphate65 00 Fango,collected from arange of hot so were reported in The major teichoi units 74 and 75:however.it could not be determined in what i-yoero-phoschate ratio.The minor teichoic acid fraction TA2 showed a lot more 2.5 Carbohydrates 79(in order of decreasing abundance).The study was unable to determine whether these structures are present as a single,highly A series of novel polysaccharides have been isolated from and thei 2.6 Lipids 2.6.1 Cor Th In 190 an exopolysaccharide with the repeating unit67was the lipids isolated from other microorganisms.They contain 0r40 areinked rid ether inka to glyeerol or a polyol.rather than S.thermophilus strain SFil2,were reported in 1997.Later the e produced byS sisti revers istry to tha d in oth of branched he 0.a cidophilic At a similar reported in 2001. time,de Rosa et al.reported the isolation of "calditol".a nove 30-Gap-(1→3Hp0-G1-→3a-D-GalpNAc-1- [-D-Galp 68 p-D-Galp →2ul-Rnep(1-→2a-0Gap(1→3)a-0-Gcp1→3-a-DGap(1-→3aL-R3p1→ 69 Bo.Galp-1-→6jp-DGa →2-t-D-Galp-(1→3)--D-Galp(1-3-D-Gp1+3-L-Rh8p1→2-aL-Rh8p(1→ 70 B-D-Gal/2Aco -6f-D-Gap-(1-6)a-D-Gap-(1-3)f-L-Rhap(1-4)-p-D-Glcp(1-8)a-D-Gaf-(1-8)-p-D-Glcp-(1- -3-B-D-Cap(1-+3)-a-D-Gdlp(1--3-at-Rhap(1-2a-0-Galp(1- ai-Rhap 71 This joumal isThe Royal Society of Chemistry 2009 Nat.Prod..Rep,2009.26,44-71|49
Vulcano island, Italy, was found to produce the osmolyte di-glycerol-phosphate 66. 72–74 2.5 Carbohydrates A series of novel polysaccharides have been isolated from thermophilic microorganisms. Streptococcus thermophilus is a thermophilic (grows at 45 C but not at 15 C) bacteria isolated from yoghurt, cheese and their starter cultures.75 The species status of S. thermophilus has been widely debated. S. thermophilus was reclassified as Streptococcus salicarius ssp. thermophilus in 198476 before being reinstated as a species in 1991,75 which has been supported in the recent literature.77 In 1990 an exopolysaccharide with the repeating unit 67 was reported from S. thermophilus strains CNCMI 733, 734 and 735.78 The structures of a further two exopolysaccharide repeating units, 68 from S. thermophilus strain SFi39 and 69 from S. thermophilus strain SFi12, were reported in 1997.79 Later the same year, the exopolysaccharide produced by S. thermophilus strain OR 90 was reported, with the repeating unit consisting of branched heptasaccharide 70. 80 The repeating unit of the exopolysaccharide of S. thermophilus strain SE 71 was reported in 2001. This exopolysaccharide contains 0.4 equivalents of O-acetyl groups per repeating unit.81 Finally, a further exopolysaccharide, 72, from S. thermophilus strain EU20, was also reported in 2001.82 Thermus thermophilus60 (strain HB8) was found in 2005 to produce a novel polysaccharide 73, which consisted of a disaccharide repeating unit to which a trisaccharide chain is linked nonstoichiometrically.40,83 The structures of the components of the two teichoic acid fractions from the Gram-positive thermophilic (opt. 55–65 C) bacteria Geobacillis thermoleovorans (previously Bacillus thermoleovorans) 84 strain Fango, collected from a range of hot soil and mud samples, were reported in 2006.85,86 The major teichoic acid fraction TA1 was seen to consist of two different repeating units 74 and 75; however, it could not be determined in what ratio. The minor teichoic acid fraction TA2 showed a lot more variability. Although the major repeating units were the same as for TA1 (74 and 75), it also had the repeating units 76, 77, 78 and 79 (in order of decreasing abundance). The study was unable to determine whether these structures are present as a single, highly variable glycerol polymer with non-stoichiometric appendages or whether there are different chains which behave the same chromatographically.85 2.6 Lipids 2.6.1 Core lipids and fatty acids. The lipids of thermophilic archaea are characterized by three key structural differences to the lipids isolated from other microorganisms. They contain isoprenoid (phytanyl) chains with 15, 20, 25 or 40 carbons, rather than the straight chains of other organisms. Two of these chains are linked via ether linkages to glycerol or a polyol, rather than the ester linkage found elsewhere. The glycerol found in archaea, 2,3-di-O-sn-glycerol 80, has the reverse stereochemistry to that found in other organisms.87,88 Novel lipids have also been isolated from thermophilic microorganisms which contain the more traditional ester linkage. In 1974, Langworthy et al. reported the isolation of glycolipid B, a novel polyol of undetermined structure from the thermoacidophilic Solfolobus acidocaldarius strain 98.3.89 At a similar time, de Rosa et al. reported the isolation of ‘‘calditol’’, a novel This journal is ª The Royal Society of Chemistry 2009 Nat. Prod. Rep., 2009, 26, 44–71 | 49
→3Ga1-→3-GaINAc-(1- →10-G0-(3P→1Go(3P a-Glc(1->6)-a-ManNAc-(1->4)-a-Man-(1-4) →1)-Gro3pao-Gdp a-D-Gicp 73 74 75 76 →1-Go(3P →1-Gro-(3p →-o-3P w-D-GIcpNAc-(1-2)-u-O-Gkcp a-D-GICpNAc-(1-3)--D-Glcp 78 79 amounts of 111 and 112.These diols were found to be linked to glycan head groups,which were not fully character ture of the calditol from S.acidocaldarius to be 83which was dentcal to the calditol of s.as determined by HO A novel class of lipids (Table 4)was first isolated from ther moacidophiles in the 1970s.These molecules feature two C 108 10g ns wh OH dialkyl-calditol-tetraethers-GDNTs(as calditol was originally thought to be a nonito 11 85 ynthesist and the chains contain 04 evclopentaneg The polar lipids of archaea are typically substituted on the free hydroxyl group of the glycerol head group and have ber growtl may b nly An ontaining a“broken Cochain (f)has also beer ted The structure of a major glycolipid from Thermus oshima total lipid NTU-063 (opt.70C)isolated from Wu-rai hot springs,Tai- was sreported n B-Gicp-( 6P- eth Th the -acyl estr of the are mainly from C that GL-I of T.SPS-1 (from Portu X9 this study did not carbohydrate Also in2004 the major polar glycolipids of FU107 as ha ing me The novel fatty acid 15,16-dimethyl-30-glyceryloxy- (1-1-glycerol diester where the glycerol esters were mainly -and anteiso-branched C hydroxyl C laty nally Therm 4A3 )(opt.60 and opt.73showed the presence of novel ongchain -dio with one f three carbohvdrate backbones (AC).of 109(major component)and 110(minor component),as well as which the stereochemistry of the linkages was not determined. 501 Nat.Prod.Rep2009,26,44-71 This journal isThe Royal Society of Chemistry009
nonitol from the thermophile Solfolobus solfataricus (previously Caldariella acidophilia). Calditol was assigned a branched chain nonitol structure 81 with no stereochemistry determined.90 In 1995 the calditol of S. acidocaldarius was assigned the structure 82 by Sugai et al.91 Total synthesis in 1999 confirmed the structure of the calditol from S. acidocaldarius to be 8392 which was identical to the calditol of S. solfataricus, as determined by further studies.93 A novel class of lipids (Table 4) was first isolated from thermoacidophiles in the 1970s. These molecules feature two C40 isoprenoid chains which are linked to either two molecules of glycerol (the glycerol-dialkyl-glycerol-tetraethers – GDGTs) or to a molecule of glycerol and a molecule of calditol (glyceroldialkyl-calditol-tetraethers – GDNTs (as calditol was originally thought to be a nonitol (see above)). The alkyl chains were originally assigned an antiparallel orientation (84),99 but more recent studies have indicated that the diglycerol tetraethers may actually be present as a combination of regioisomers (84 + 85).100 The chirality of the C40 chains has been confirmed by total synthesis101 and the chains contain 0–4 cyclopentane groups (a–e), with the amount of cyclisation observed to increase as growth temperature rises.102 The two alkyl chains may be the same or different (see Table 4, 86–106). An isomer (101) containing a ‘‘broken’’ C40 chain (f) has also been isolated.97 A novel core lipid, FU, was isolated from the total lipid fraction of Methanothermus fervidus in 1998.103 Methanothermus fervidus is a hyperthermophilic (opt. 83 C) methanogen isolated from an Icelandic hot spring.104 The most likely structure for FU is a bridged version of GDGT (a + a) 107, although the exact position of the bridge has not been fully confirmed.103 The novel fatty acid 15,16-dimethyl-30-glyceryloxytriacontanoic acid 108 was isolated from a thermophilic (opt. 80 C) and mildly halotolerant (tol. 0.25–3.75% NaCl) strain of anaerobic bacteria isolated from geothermally heated sea floors in the Azores and Italy.52,105 Acid hydrolysis of the glycolipids of the thermophiles Thermus scotoductus X-1 (opt. 65 C)106 and Thermus filiformis Tok4 A2 (opt. 73 C)107 showed the presence of novel long-chain 1,2-diols, 109 (major component) and 110 (minor component), as well as trace amounts of 111 and 112. These diols were found to be linked to glycan head groups, which were not fully characterized.108 T. scotoductus X-1 was collected from hot tap water in Iceland and T. filiformis Tok4 A2 was collected from a hot spring in New Zealand.107 2.6.2 Glyco- and phospholipids. 2.6.2.1 Ether-linked The polar lipids of archaea are typically substituted on the free hydroxyl group of the glycerol head group and have been reviewed in the literature.87,109,110 Only the isolation of novel structures not included in these reviews will be discussed herein. The structure of a major glycolipid from Thermus oshimai NTU-063 (opt. 70 C)111 isolated from Wu-rai hot springs, Taiwan, was reported in 2004 to be b-Glcp-(1/6)-b-Glcp-(1/6)-bGlcp-NAcyl-(1/2)-a-Glcp-(1/1)-glycerol diester. The N-acyl group is either C15:0 or C17:0 and the O-acyl esters of the glycerol are mainly from C15:0–C18:0 including straight, isobranched and anteisobranched fatty acids.112 Previously it had been shown that GL-1 of T. oshimai SPS-11 (from Portuguese hot springs) has the same carbohydrate sequence and similar fatty acid composition,111,113 but this study did not determine the linkage or configuration, hence it cannot be claimed that they have identical carbohydrate moieties.112 Also in 2004 the major polar glycolipids of Meiothermus taiwanensis ATCC BAA-400 were reported as having the structure b-Galp-(1/6)-b-Galp-(1/6)-b-Gal-NAcyl-(1/2)-a-Gly- (1/1)-glycerol diester where the glycerol esters were mainly iso- and anteiso-branched C15:0 and C17:0 and the N-acyl is a C17:0 or hydroxyl C17:0 fatty acid.114 Glycolipids from a further four Meiothermus species, M. ruber, M. cerbereus, M. silvanus (originally Thermus silvanus) 115 and M. chliarophilus (originally Thermus chliarophilus) 115 (opt. 60 C,27 55 C,116 55 C117 and 50 C117 respectively) were reported in 1999. Each strain produced glycolipids with one of three carbohydrate backbones (A–C), of which the stereochemistry of the linkages was not determined, 50 | Nat. Prod. Rep., 2009, 26, 44–71 This journal is ª The Royal Society of Chemistry 2009
Table4 Tetracther lipids of archaea 人人)H8 HO OH -OH OHOHOHOHOHOHO HO ,H0 OH HO 2.3-di--sn-glycerol 80 81 R-OH GDGT H.-isoprenyl-0 H.o-isoprony- OH o-isoprenyl-H o-isoprenyt0 GDNT 84 85 人 GDGT/GDNT (isoprenyl chains) Year isolated Microorganism GDGT (a +a)86,GDGT (b+b)87,GDGT (e+e)88 1977 G,909D04 1980 GD DOTDT 198 Sulfolobus solfataricus cDTe·LCDNF 10 Thermoproteus tenax strain Kra-1 This joumal isThe Royal Society of Chemistry 2009 Nat.Prod..Rep,2009,26,44-7115T
Table 4 Tetraether lipids of archaea GDGT / GDNT (isoprenyl chains) Year isolated Microorganism GDGT (a + a) 86, GDGT (b + b) 87, GDGT (c + c) 88 1977 Solfolobus solfataricus (previously Caldariella acidophila) strain MT394,95 and Thermoplasma acidophilum (GDGT (a + a))96 GDGT (d + d) 89, GDGT (e + e) 90, GDNT (a + a) 91, GDNT (b + b) 92, GDNT (c + c) 93, GDNT (d + d) 94, GDNT (e + e) 95 1980 Solfolobus solfataricus strain MT490,95 GDGT (a + f) 96, GDGT (a + b) 97, GDGT (b + c) 98, GDGT (c + d) 99, GDGT (d + e) 100, GDNT (a + f) 101, GDNT (a + b) 102, GDNT (b + c) 103, GDNT (c + d) 104, GDNT (d + e) 105 1983 Sulfolobus solfataricus97 GDGT (a + c) 106 1988 Thermoproteus tenax strain Kra-198 This journal is ª The Royal Society of Chemistry 2009 Nat. Prod. Rep., 2009, 26, 44–71 | 51
Gkc-GIc-GaINR'.Glc-O-CHzCHRCH,R 9 Gkc-Gal-GaIWRGkc-O-CH-CHR>CH.R 9 Gkc-Gal-GIcNR'-Glc-O-CH.-CHR-CHaR GLla GL-lb Strain Backbone R'% R2(% R) R2% M ruber A 2.0HCm90 B 2.0HCm≥90 CeSol M.silvanus 2-0HC2n(83) C1s077 C10(6. M.chliarophils 2.0HC,m90 60(5. Cra (5) Ci (4. and showed two bands of glycolipids by thin layer chromatog Table 6 from a hot s which cont cosylin R he R3 Isoprenyl chains lyses in the pres GL-I B-Gulose + 120 群 Most abundant isoprenyl chain listed;see Table 4 for structures OH OH OH AG1113 2.6.2.2 Ester-linked.A novel glycolipid was isolated from the OH cture 一0-Ca4 OH hexadecanoyl)-(12)-Glcp digl ceride The structure of two myo-inositol- 0-C2H4 major glycolipids GLI 121 and GL2 122 and a phospholipid o-C20H41 o with most ab amu-S The th A114 115 mohalophilic strain Samu-SAl (opt.75C and%w NaCl) a5 m a depth of0m in a hot spring on Mount ated thermoacidophile (opt. ThePGLl 124d PGL212re 59C and pH 1.0-2.0)collected from a smoldering coal pile in isolated from the thermophiles Thermus oshimai NTU-063. 521 Nat.Prod.Rep2009,26,44-77 This journal isThe Royal Society of Chemistry009
and showed two bands of glycolipids by thin layer chromatography (GL-1a and GL-1b) due to differing substitution on the polar head group (see Table 5).118 M. cerbereus was first isolated from a hot spring in the Geysir geothermal region of Iceland.116 The isolation of two novel polar lipids AGI 113 and AI 114 from Aeropyrum pernix K1 which contained glucosylinositol as the polar head group was reported in 1999.119 Aeropyrum pernix is a hyperthermophilic (opt. 90–95 C) archaeon which was isolated from a coastal solfataric thermal vent off Kodakara-Jima Island, Japan.120 A structurally similar novel glycolipid 115 was isolated from the thermohalophilic (grows at up to 93 C and lyses in the presence of less than 3.5% NaCl) archaeon Thermococcus celer, which was collected from a marine water hole on Vulcano island, Italy.121,122 In 1999, the structures of five novel neutral glycolipids (116– 120, Table 6) were reported.123 These glycolipids had been isolated from Thermoplasma acidophilum, a thermoacidophile (opt. 59 C and pH 1.0–2.0) collected from a smoldering coal pile in the USA, and consisted of GDGTs which were substituted on one or both of the free hydroxyls.8 2.6.2.2 Ester-linked. A novel glycolipid was isolated from the thermophile (opt. 65–72 C) Thermus thermophilus (previously Flavobacterium thermophilum124) HB-8 in 1974. Its structure was determined to be Galf-(1/2)-Galp-(1/6)-GlcN(15-methylhexadecanoyl)-(1/2)-Glcp-diglyceride.125 The structure of two major glycolipids GL1 121 and GL2 122 and a phospholipid PGL 123 from T. thermophilus strain Samu-SA1 was published in 2006 (shown with most abundant chain lengths).126 The thermohalophilic strain Samu-SA1 (opt. 75 C and 2% w/v NaCl) was isolated from a depth of 60 m in a hot spring on Mount Grillo, Naples, Italy.127 The novel phosphoglycolipids PGL1 124 and PGL2 125 were isolated from the thermophiles Thermus oshimai NTU-063, Table 5 Glycolipids from Meiothermus species Strain Backbone GL-1a GL-1b R1 (%) R2 (%) R1 (%) R2 (%) M. ruber A 2-OH C17:0 (>90) C15:0 (89), C16:0 (3), C17:0 (8) C15:0 (30), 3-OH C15:0 (13), C17:0 (27), 3-OH C17:0 (30) C15:0 (91), C16:0 (3), C17:0 (8) M. cerbereus B 2-OH C17:0 >90) C15:0 (2), C16:0 (10), C17:0 (18) 3-OH C17:0 (>90) C15:0 (76), C16:0 (10), C17:0 (14) M. silvanus B 2-OH C17:0 (83), 2-OH C16:0 (12) C15:0 (75), C16:0 (5), C17:0 (20) C15:0 (43), C16:0 (10), C17:0 (42), 3-OH C17:0 (5) C15:0 (77), C16:0 (6), C17:0 (17) M. chliarophilus C 2-OH C17:0 (>90) C15:0 (74), C16:0 (5), C17:0 (20) C17:0 (>90) C15:0 (72), C16:0 (4), C17:0 (23) Table 6 Neutral glycolipids from Thermoplasma acidophilum Compound R1 R2 Isoprenyl chainsa 116 GL-1a b-Gulose OH b + b 117 GL-1b a-Glucose OH a + a 118 GL-2a b-Gulose b-Gulose b + b 119 GL-2b b-Gulose a-Glucose b + b 120 GL-2c a-Glucose a-Glucose b + b a Most abundant isoprenyl chain listed; see Table 4 for structures. 52 | Nat. Prod. Rep., 2009, 26, 44–71 This journal is ª The Royal Society of Chemistry 2009
8 HO HO OH OH HOHO GL112 G2122 PGL 12 Therms thermophilus NTU-077,Meiothermus ruber NTU-124 which were from hot springs in Taiwan.While PSL HO ructurally similar to a phospholy on-to he ratio of iso to ratio of PGL2 to PGLI increased with increasing culture emperature wo r iis a reddis -brown thermophilic(opt a Japanese hot pringThe lipid composition strain HLOS has been investigated and the dominant al lipic extrac were Ioun a to an 135 OH OR 29WaNcsesweepeetsminorcomponcntsTangingfiom 骨溜 tetra-o 131and derivatives 132 了adeg7 then lg小yce ides of B.acidocaldarius were partially characterized to be 134 OH 0=0 HO NH HO 0 PGL1 124 PGL2 125 This joumal isThe Royal Society of Chemistry 2009 Nat.Prod..Rep,2009.26,44-71|53
Thermus thermophilus NTU-077, Meiothermus ruber NTU-124 (originally Thermus ruber115) and Meiothermus taiwanensis NTU- 220 (opt. 70 C,111 65–72 C,40 60 C27 and 55 C128 respectively), which were collected from hot springs in Taiwan. While PGL1 124 is structurally similar to a phosphoglycolipid from the radiation-tolerant Deinococcus radiodurans, 129 PGL2 125 is the first phospholipid identified with a 2-acylalkyldio-1-O-phosphate moiety. The fatty acids were found to be mainly iso-branched C15:0, C16:0 and C17:0 and anteiso-branched C15:0 and C17:0 fatty acids with the ratio of iso to anteiso fatty acids increasing at higher culture temperatures. In all strains but T. oshimai, the ratio of PGL2 to PGL1 increased with increasing culture temperature.130 Two novel glycolipids 126 and 127 with the very rare a(1/4) diglucosyl structure were isolated from the thermophile Thermotoga maritima in 1992.131 Roseiflexus castenholzii is a reddish-brown thermophilic (opt. 50 C) bacteria which was isolated from a bacterial mat in a Japanese hot spring.132 The lipid composition of R. castenholzii strain HLO8T has been investigated and the dominant compounds in the total lipid extract were found to be alkane- 1,2-diol-based glycosides with the major isomers being 128 and 129. Wax esters were present as minor components ranging from 37 to 40 carbons in length.133 A novel Lipid A with the unique structure 130 was isolated from the Gram-negative thermophile Aquifex pyrophilus in 2000.134,135 Pentacyclic tetra-ol 131 and two glucosamine derivatives 132 and 133 were isolated from the glycolipid fraction of Bacillus acidocaldarius in 1976. In the same study the diglucosyl glycerides of B. acidocaldarius were partially characterized to be 134 This journal is ª The Royal Society of Chemistry 2009 Nat. Prod. Rep., 2009, 26, 44–71 | 53