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|53Thermus 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 Ther￾motoga 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 glycer￾ides 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