<Emphasis Type="Italic">Streptomyces serianimatus</Emphasis> sp. nov., isolated from a rhizophere soil

A novel actinomycete strain, designated YIM 45720^T, was isolated from a Cephalotaxus fortunei rhizophere soil sample collected from Yunnan Province, southwest China. The strain formed well-differentiated aerial and substrate mycelia. Chemotaxonomically, it contained LL-diaminopimelic acid in the cell wall. The cell-wall sugars contained ribose, mannose, and galactose with traces of glucose and xylose. Phospholipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and phosphatidylinositol. MK-9 (H₈) was the predominant menaquinone. The major fatty acids (>10%) were iso-C_16:0, iso-C_15:1 and anteiso-C_15:0. The G + C content of the DNA was 70 mol%. Phylogenetic analysis data based on 16S rRNA gene sequence showed that strain YIM 45720^T formed a distinct branch with the type strain of Streptomyces scabrisporus JCM 11712^T within the genus Streptomyces. On the basis of the phenotypic and genotypic characteristics, strain YIM 45720^T (=DSM 41883^T = CCTCC AA 206006^T) is proposed as the type strain of a novel species, Streptomyces serianimatus sp. nov.     

<Emphasis Type="Italic">Streptomyces roseoalbus</Emphasis> sp. nov., an actinomycete isolated from soil in Yunnan,China

A strain YIM 33098T (= CCTCC AA001027T = DSM 41831T) was isolated from a forest soil sample collected from Nanning in Guangxi Province, China, in the course of screening for producers of new drug lead compounds. This strain was identified by using a polyphasic approach. The results showed that it should be assigned to the genus Streptomyces. An almost complete 16S rRNA gene sequence of the strain was determined and compared with those of representative Streptomyces species. Strain YIM 33098T was clustered in the same subclade with Streptomyces tendae ATCC19812T and Streptomyces eurythermus ATCC14975T. Similarities of strain YIM 33098T with the two strains were 97.35% and 97.42%, respectively. Based on the phenotypic and genotypic evidence, it is therefore proposed that strain YIM 33098T should be classified in the genus Streptomyces as a new species under the name of Streptomyces nanningensis sp. nov.     

Streptomyces manipurensis sp. nov., a novel actinomycete isolated from a limestone deposit site in Manipur, India

A novel actinobacterium, designated MBRL 201(T), was isolated from a sample collected from a limestone quarry at Hundung, Manipur, India. The strain was characterized using polyphasic taxonomy. Comparison of the 16S rRNA gene sequence of strain MBRL 201(T) and other Streptomyces species showed sequence similarities ranging from 93.0 to 99.6 % and strain MBRL 201(T) showed closest similarities to Streptomyces virginiae NBRC 12827(T) (99.6 %) and Streptomyces cinnamonensis NBRC 15873(T) (99.6 %). The DNA relatedness between MBRL 201(T) and the type strains of S. virginiae NBRC 12827(T) and S. cinnamonensis NBRC 15873(T) were 44.5 and 35.6 % respectively. Strain MBRL 201(T) contained LL: -diaminopimelic acid (A(2)pm) as the diagnostic diamino acid, with glucose as the main sugar, while small amounts of galactose, glucose, mannose, rhamnose, ribose and xylose were also present in cell-wall hydrolysates. The major fatty acids identified were anteiso-C(15:0) (38.9 %), iso-C(15:0) (19.9 %) and anteiso-C(17:1) (14.7 %). The predominant menaquinones detected were MK-9(H(6)) and MK-9(H(8)), while the polar lipids were diphosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositolmannosides, with other unknown phospholipids and lipids. The G+C content of the genomic DNA was 72.9 %. The phenotypic and genotypic data showed that strain MBRL 201(T) merits recognition as a representative of a novel species of the genus Streptomyces. It is proposed that the isolate should be classified in the genus Streptomyces as a novel species, Streptomyces manipurensis sp. nov. The type strain is MBRL 201(T) (=DSM 42029(T)?=?JCM 17351(T)).     

Herminiimonas aquatilis sp. nov., a new species from drinking water

A bacterial strain (CCUG 36956T) isolated from drinking water was taxonomically studied in detail. Phylogenetic analyses using the 16S rRNA gene sequence of the isolate indicated that it belongs to family Oxalobacteraceae of the beta-subclass of the Proteobacteria, with the highest sequence similarity of 99.3% to the type strain of Herminiimonas fonticola. In the polyamine pattern putrescine and 2-hydroxyputrescine were the predominant compounds. In the polar lipid profile major compounds were phosphatidyl ethanolamine and diphosphatidyl glycerol. Phosphatidyl glycerol and an unknown phospholipid were detected in moderate proportions. The major respiratory quinone was a ubiquinone Q-8 and the major whole cell fatty acids were 16:1 omega7c, 17:1 omega6c, and 16:0. The strain also contained 10:0 3-OH and other fatty acids typical for members of the genus Herminiimonas. The results of DNA-DNA hybridizations and physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain CCUG 36956T from H. fonticola. For this reason, we propose that strain CCUG 36956T represents a new species of the genus Herminiimonas for which we propose the name Herminiimonas aquatilis sp. nov.     

<Emphasis Type="Italic">Streptomyces gulbargensis</Emphasis> sp. nov., isolated from soil in Karnataka,India

During the course of screening for industrially important microorganisms, an alkali-tolerant and thermotolerant actinomycete, strain DAS 131T, was isolated from a soil sample collected from the Gulbarga region, Karnataka province, India. The strain was characterized by a polyphasic approach that showed that it belonged to the genus Streptomyces. Growth was observed over a wide pH range (pH 6-12) and at 45 degrees C. The 16S rRNA gene sequence of strain DAS 131T was deposited in the GenBank database under the accession number DQ317411. 16S rRNA gene sequence analysis revealed that strain DAS 131T was most closely related to Streptomyces venezuelae ISP 5230T (AY999739) with a sequence similarity of 99.5% (8 nucleotide differences out of 1,477). Despite this very high sequence similarity, strain DAS 131T was phenetically distinct from S. venezuelae. The DNA relatedness between these strains was 54%, indicating that strain DAS 131T is a distinct genomic species. On the basis of phenetic and genetic analyses, strain DAS 131T is classified as a new species in the genus Streptomyces, for which we propose the name Streptomyces gulbargensis sp. nov.     

<Emphasis Type="Italic">Acinetobacter soli</Emphasis> sp. nov., isolated from forest soil

A non-motile and rod shaped bacterium, designated strain B1(T), was isolated from forest soil at Mt. Baekwoon, Republic of Korea. Cells were Gram-negative, catalase-positive, and oxidase-negative. The major fatty acids were 9-octadecenoic acid (C(18:1) omega9c; 42%) and hexadecanoic acid (C(16:0); 25.9%) and summed feature 3 (comprising iso-C(15:0) 2-OH and/or C(16:1) omega7c; 10.0%). The DNA G+C content was 44.1 mol%. A phylogenetic tree based on 16S rRNA gene sequences showed that strain B1(T) formed a lineage within the genus Acinetobacter and was closely related to A. baylyi DSM 14961(T) (98.6% sequence similarity), followed by A. baumannii DSM 30007(T) (97.4%), A. calcoaceticus DSM 30006(T) (97.0%) and 3 genomic species (96.8 approximately 7.6%). Phenotypic characteristics, gyrB gene sequence analysis and DNA-DNA relatedness data distinguished strain B1(T) from type strains of A. baylyi, A. baumannii, and A. calcoaceticus. On the basis of the evidence presented in this study, strain B1(T) represents a novel species of the genus Acinetobacter, for which the name Acinetobacter soli sp. nov. is proposed. The type strain is B1(T) (= KCTC 22184(T)= JCM 15062(T)).     

Determination of the structure of a novel glycolipid from Thermus aquaticus 15004 and demonstration that hydroxy fatty acids are amide linked to glycolipids in Thermus spp.

The compositions of the major glycolipids (GL-1) of five strains of Thermus aquaticus, the type strain of T. filiformis, T. oshimai SPS-11, and Thermnus sp. strain CG-2 were examined by gas chromatography, gas chromatography-mass spectroscopy, fast atom bombardment-mass spectroscopy, and chemical methods. The results showed that, with the exception of T. aquaticus 15004, the organisms each have a major glycolipid whose structure was established as diglycosyl-(N-acyl)glycosaminyl-glycosyl diacylglycerol. Glucosamine was present in GL-1 of T. oshimai SPS-11 and Thermus sp. strain CG-2, while galactosamine was present in the GL-1 of T. aquaticus and T. filiformis. The novel major glycolipid of T. aquaticus 15004 was identified as galactofuranosyl-(N-acetyl)galactosaminyl-(N-acyl)galactosaminyl-gluc - osyl diacylglycerol. The hydroxy fatty acids found in the T. aquaticus strains and in the type strain of T. filiformis were exclusively amide linked to the galactosamine of the major glycolipid. Ester-linked hydroxy fatty acids were not detected in the diacylglycerol moiety of GL-1 of these organisms. Hydroxy fatty acids were detected neither in the major glycolipid of T. oshimai SPS-11 and Thermnus sp. strain CG-2, in which glucosamine is present, nor in the major phospholipid of any of the strains examined.     

Fatty acid composition of <Emphasis Type="Italic">Wautersia eutropha</Emphasis> lipids under conditions of active polyhydroxyalkanoates synthesis

The fatty acid composition of the lipids of a Wautersia eutropha polyhydroxyalkanoate-producing strain was studied by chromato-mass spectrometry. A total of 27 fatty acids were identified; their distribution in the cell fractions was determined. In the cytoplasmic membrane, palmitic, palmitoleic, and cis-vaccenic acids were the major components. Long-chain β-hydroxy acids and myristic acids (components of the lipopolysaccharides of the cell envelope) predominated in the fraction of strongly bound lipids. When the polymer was actively synthesized, the content of cyclopropane acids in the easily extracted lipids increased and the content of the corresponding monoenoic acids decreased. The strongly bound lipids had a high content of long-chain β-hydroxy acids (more than 50% of the total fatty acids). These results made it possible to determine the source of polyhydroxyalkanoate (PHA) contamination and to choose the strategy for their purification.     

Rapid selection of mutants of <Emphasis Type="Italic">Chlamydomonas reinhardtii</Emphasis> for carbohydrate and fatty acid metabolism by fourier transform infrared spectroscopy and gas chromatography combined with multivariate analysis

Transgene-tagged mutants of Chlamydomonas reinhardtii were generated by random insertional mutagenesis for screening of mutants of carbohydrate and fatty acid metabolism. Approximately 2,500 insertion mutants tagged with the aph7″ gene were produced from one mutagenesis in three weeks. To establish a rapid screening system for numerous insertional lines, whole cell extracts of 100 insertional lines were subjected to Fourier transform infrared spectroscopy (FT-IR) and gas chromatography (GC) analysis combined with multivariate analysis. Mutant lines 28, 67, and 90 showed dramatic differences in the carbohydrate (1,000∼1,200 cm⁻¹) and amide (1,500∼1,700 cm⁻¹) regions of the FT-IR spectrum compared to wild type strain CC-124. Separate GC analysis also showed that 16:0 iso, palmitic acid (16:0), and oleic acid (18:1) were the major fatty acids in the wild type strain. In mutant 80, the relative content ratio of 16:0 iso in total fatty acids was significantly lower than in wild type, whereas the ratios of palmitic acid and oleic acid to 16:0 iso were higher. In mutant 95, the ratio of 16:0 iso to total fatty acids was increased, whereas ratios of palmitic acid and oleic acid to 16:0 iso were decreased. In particular, mutant 57 showed remarkably different fatty acid patterns with novel peaks of long-chain fatty acids having more than 20 carbon atoms. The results of this study show that FT-IR and GC combined with multivariate analysis enable rapid selection of mutants of carbohydrate and fatty acid metabolism in C. reinhardtii.     

Gracilibacillus quinghaiensis sp. nov., isolated from salt-lake sediment in the Qaidam Basin, north-west China

A motile, Gram-positive, slightly halophilic, endospore-forming, catalase- and oxidase-positive, obligately aerobic, slender rod-shaped bacterium, strain YIM-C229T was isolated from the sediment of a salt lake in the Qaidam Basin, north-west China. Filamentous forms were present throughout the growth cycle. Strain YIM-C229T grew in the presence of 0.5-8% NaCl and at pH 6.0-8.5, with optimum growth at 1-3% NaCl and pH 7.0-7.5. It grew at 4-45 degrees C, with optimum growth at 37 degrees C. The major cellular fatty acids were anteiso-C15:0, C16:0, iso-C15:0, C16:1 omega11c and anteiso-C(17:0). The predominant respiratory quinone was MK-7, and diphosphatidylglycerol and phosphatidylglycerol were the polar lipids, with meso-diaminopimelic acid occurring in the cell-wall peptidoglycan. The genomic DNA G+C content was 40.9 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YIM-C229T was closely related to the type strains of the four recognized species of the genus Gracilibacillus: G. halotolerans NN T (sequence similarity 95.5%), G. dipsosauri DD1T (96.1%), G. orientalis XH-63T (96.8%) and G. boraciitolerans T-16X(T) (99.1%). The DNA-DNA relatedness between strain YIM-C229(T) and G. boraciitolerans DSM 17256(T) was 30.8%. The combination of phylogenetic analysis, phenotypic characteristics, chemotaxonomic differences and DNA-DNA hybridization data supported the view that this strain represented a novel species of the genus Gracilibacillus, for which the name Gracilibacillus quinghaiensis sp. nov. is proposed, with YIM-C229T (=DSM 17858T=CGMCC 1.6304T) as the type strain.     

<Emphasis Type="Italic">Paenibacillus ginsengisoli</Emphasis> sp. nov., a novel bacterium isolated from soil of a ginseng field in Pocheon province,South Korea

A Gram-positive, aerobic or facultative anaerobic, motile, spore-forming bacterial strain, designated Gsoil 1638T, was isolated from a soil sample of a ginseng field in Pocheon province (South Korea), and was characterized taxonomically by using a polyphasic approach. It grew well on nutrient agar medium, utilized a fairly narrow spectrum of carbon sources and tolerated 10% NaCl. The isolate was positive for catalase and oxidase tests but negative for the degradation of macromolecules such as casein, collagen, starch, chitin, CM-cellulose, xylan and DNA. The G + C content of the genomic DNA was 50.7 mol%. The predominant isoprenoid quinone was menaquinone 7 (MK-7). The major fatty acids were anteiso-C15:0 (44%) and C16:0 (25%). Comparative 16S rRNA gene sequence analysis showed that strain Gsoil 1638T fell within the radiation of the cluster comprising Paenibacillus species and joined Paenibacillus anaericanus DSM 15890T with a bootstrap value of 100%. These two strains shared 99.5% 16S rRNA gene sequence similarity with each other. The phylogenetic distance from any other validly described species within the genus Paenibacillus was less than 96.2%. DNA-DNA relatedness value between strain Gsoil 1638T and its closest phylogenetic neighbor, Paenibacillus anaericanus, was 62%. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain Gsoil 1638T (= KCTC 13931T = LMG 23406T = CCUG 52472T) was classified in the genus Paenibacillus as the type strain of a novel species, for which the name Paenibacillus ginsengisoli sp. nov. is proposed.     

Endozoicomonas elysicola gen. nov., sp. nov., a gamma-proteobacterium isolated from the sea slug Elysia ornata

A Gram-negative, strictly aerobic, rod-formed bacterium, strain MKT110(T), was isolated from a mollusk, the sea slug Elysia ornata collected in seawater off the coast of Izu-Miyake Island, Japan at a depth of 15m. Comparative 16S rRNA gene sequences analysis indicated that the isolate MKT110(T) constituted a novel lineage in gamma-proteobacteria related to the genera Zooshikella, Oceanospirillum, Microbulbifer, Marinobacter, Saccharospirillum and Pseudomonas. The strain MKT110(T) was closely related to the clones from marine sponge Halichondria okadai (AB054136, AB054161) and the coral Pocillopora damicornis (AY700600, AY700601). The phylogenetic tree based on the 16S rRNA gene sequences showed that MKT110(T) and four clones formed a sub-lineage related to the genus Zooshikella, with a bootstrap value of 100%. MKT110(T) required salt for its growth and was mesophilic. The bacterium contained 16:1omega7c, 16:0 and 14:0 as major cellular fatty acids, and 3-OH 14:0, 3-OH 10:0 and 3-OH 12:0 as major hydroxy fatty acids. The DNA base composition of the isolate was 50.4 mol% G+C. The major quinone was Q-9. The bacterium is distinguished from currently recognized bacterial genera based on phylogenetic and phenotypic features and should be classified in a novel genus for which the name Endozoicomonas elysicola gen. nov., sp. nov. is proposed. (type strain MKT110(T)=IAM 15107(T)=KCTC 12372(T); GenBank accession no. AB196667).     

Tepidimonas aquatica sp. nov., a new slightly thermophilic beta-proteobacterium isolated from a hot water tank

A bacterial isolate, with an optimum growth temperature of about 50 degrees C, was recovered from a domestic hot water tank in Coimbra. Phylogenetic analysis using 16S rRNA gene sequence indicated that strain CLN-1T is a member of the beta-Proteobacteria and represents a new species of the genus Tepidimonas. The major fatty acids of strain CLN-1T are 16:0, 17:0 cyclo and 16:1 omega7c. Ubiquinone 8 is the major respiratory quinone, the major polar lipids are phosphatidylethanolamine, and phosphatidylglycerol. The new isolate is aerobic and facultatively chemolithoheterotrophic. Thiosulfate and tetrathionate are oxidized to sulfate in the presence of a metabolizable carbon source. Strain CLN-1T grows on amino acids and organic acids, but this organism does not assimilate carbohydrates. Glycerol is the only polyol assimilated. Resinic acids, namely abietic acid, dehydroabietic acid and isopimaric acid are not degraded. On the basis of the phylogenetic analyses, physiological and biochemical characteristics, we propose that strain CLN-1T represents a new species for which we offer the name Tepidimonas aquatica.     

Zinc tolerance of an isolated bacterium containing ω-cyclohexyl fatty acid

Abstract ω-Cyclohexyl undecanoic acid, an unusual fatty acid, was found in a bacterium isolated from a soil with added zinc. The ω-cyclohexyl fatty acid accounted for 46% of total fatty acids and was the most abundant fatty acid in bacteria grown in T medium. In addition, 12-methyl tetradecanoic acid (27%) and 14-methyl hexadecanoic acid (23%) were also quantitatively major fatty acids. The bacteria grew almost normally in the Zn-enriched medium, and their ω-cyclohexyl undecanoic acid content increased with Zn concentration. The results suggest that the ω-cyclohexyl fatty acid may be related to the Zn tolerance of this strain.     

Quantitative study of interactions between <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> and <Emphasis Type="Italic">Oenococcus </Emphasis><Emphasis Type="Italic">oeni</Emphasis> strains

This study examines the interactions that occur between Saccharomyces cerevisiae and Oenococcus oeni strains during the process of winemaking. Various yeast/bacteria pairs were studied by applying a sequential fermentation strategy which simulated the natural winemaking process. First, four yeast strains were tested in the presence of one bacterial strain leading to the inhibition of the bacterial component. The extent of inhibition varied widely from one pair to another and closely depended on the specific yeast strain chosen. Inhibition was correlated to weak bacterial growth rather than a reduction in the bacterial malolactic activity. Three of the four yeast strains were then grown with another bacteria strain. Contrary to the first results, this led to the bacterial stimulation, thus highlighting the importance of the bacteria strain. The biochemical profile of the four yeast fermented media exhibited slight variations in ethanol, SO(2) and fatty acids produced as well as assimilable consumed nitrogen. These parameters were not the only factors responsible for the malolactic fermentation inhibition observed with the first bacteria strain. The stimulation of the second has not been reported before in such conditions and remains unexplained.     

<Emphasis Type="Italic">Streptomyces tritolerans</Emphasis> sp. nov., a novel actinomycete isolated from soil in Karnataka,India

A Gram-positive, nonmotile, moderately halophilic, alkali and thermotolerant strain designated DAS 165(T), was isolated from a dry land soil sample from the Gulbarga region, Karnataka province, India. The isolate produced yellow substrate mycelia and gray aerial mycelia on most tested media. Strain DAS 165(T) showed growth in the presence of 5 to 7% NaCl and at 45 degrees C. The DNA G + C content was 69.7%. 16S rRNA gene sequence analysis together with these characteristics consistently assigned strain DAS 165(T) to the genus Streptomyces. The 16S rRNA gene sequence analysis revealed that strain DAS 165(T) was most closely related to S. tendae ATCC 19812(T) (D 63873) with a sequence similarity of 99.6% (three nucleotide differences out of 1,517). Strain DAS 165(T) formed a distinct clade based on analysis of the almost complete sequence and 120-nucleotide variable gamma region of the 16S rRNA gene. Despite the high sequence similarity, strain DAS 165(T) was phenotypically different from S. tendae ATCC 19812(T). DNA-DNA hybridization between these strains was 47% showing that strain DAS 165(T) is a distinct genomic species. Phenetic and genetic results support the classification of strain DAS 165(T) as a new species, for which the name S. tritolerans is proposed, with strain DAS 165(T) as the type strain (=DSM 41899(T )= CCTCCAA 206013(T)).     

Production of tylosin byStreptomyces fradiae in palm oil medium

Streptomyces fradiae (NRRL 2702) produced tylosin when cultured on a synthetic defined medium M3. Palm oil, palm kernel oil and their fractions, as well as fatty acids and glycerol were investigated to serve as the major carbon source in shake flask culture. The lipids, glycerol and fatty acids, particularly palmitic acid but not oleic or lauric acid, were suitable for growth and tylosin production. For palmitic acid, at 168 h, the dry cell yield and tylosin production were 8.9 mg/ml and 0.84 mg/g cell mass respectively.     

Molecular and phenotypic comparison of phaeochromycin-producing strains of <Emphasis Type="Italic">Streptomyces phaeochromogenes</Emphasis> and <Emphasis Type="Italic">Streptomyces ederensis</Emphasis>

Streptomyces strain LL-P018 produces the phaeochromycins, novel anti-inflammatory polyketides. This organism was identified as a strain of Streptomyces phaeochromogenes by physiological and genetic taxonomic analysis. In order to gain greater taxonomic perspective, LL-P018 was compared to related strains from major culture collections by 16S rRNA gene sequence, ribotype, HPLC-MS metabolite profile, and rpoB sequence. Using BioNumerics software, genetic and chemical fingerprint data were integrated via multivariate cluster analysis into a single, robust comparison. Based upon this analysis, strain LL-P018 is very closely related to the type strains of both S. phaeochromogenes and Streptomyces ederensis, indicating that these two types may in fact represent a single species. This novel comparative multi-cluster analysis is most useful for clarifying relationships between closely related species.     

A comparison of the major lipid classes and fatty acid composition of marine unicellular cyanobacteria with freshwater species

The fatty acid composition of two motile (strains WH 8113 and WH 8103) and one nonmotile (strain WH 7803) marine cyanobacteria has been determined and compared with two freshwater unicellular Synechocystis species (strain PCC 6308 and PCC 6803). The fatty acid composition of lipid extracts of isolated membranes from Synechocystis PCC 6803 was found to be identical to that of whole cells. All the marine strains contained myristic acid (14:0) as the major fatty acid, with only traces of polyunsaturated fatty acids. This composition is similar to Synechocystis PCC 6308. The major lipid classes of the nonmotile marine strain were identified as digalactosyl diacylglycerol, monogalactosyl diacylglycerol, phosphatidylglycerol, and sulfoquinovosyl diacylglycerol, identical to those found in other cyanobacteria.Abbreviations DGDG Digalactosyl diacylglycerol - MGDG Monogalactosyldiacylglycerol - PG Phosphatidylglycerol - SGDG sulfoquinovosyl diacylglycerol - gc gas chromatography - ms mass spectrometry     

The <Emphasis Type="Italic">Lactococcus lactis</Emphasis> FabF fatty acid synthetic enzyme can functionally replace both the FabB and FabF proteins of <Emphasis Type="Italic">Escherichia coli</Emphasis> and the FabH protein of <Emphasis Type="Italic">Lactococcus lactis</Emphasis>

The genome of Lactococcus lactis encodes a single long chain 3-ketoacyl-acyl carrier protein synthase. This is in contrast to its close relative, Enterococcus faecalis, and to Escherichia coli, both of which have two such enzymes. In E. faecalis and E. coli, one of the two long chain synthases (FabO and FabB, respectively) has a role in unsaturated fatty acid synthesis that cannot be satisfied by FabF, the other long chain synthase. Since L. lactis has only a single long chain 3-ketoacyl-acyl carrier protein synthase (annotated as FabF), it seemed likely that this enzyme must function both in unsaturated fatty acid synthesis and in elongation of short chain acyl carrier protein substrates to the C18 fatty acids found in the cellular phospholipids. We report that this is the case. Expression of L. lactis FabF can functionally replace both FabB and FabF in E. coli, although it does not restore thermal regulation of phospholipid fatty acid composition to E. coli fabF mutant strains. The lack of thermal regulation was predictable because wild-type L. lactis was found not to show any significant change in fatty acid composition with growth temperature. We also report that overproduction of L. lactis FabF allows growth of an L. lactis mutant strain that lacks the FabH short chain 3-ketoacyl-acyl carrier protein synthase. The strain tested was a derivative (called the ∆fabH bypass strain) of the original fabH deletion strain that had acquired the ability to grow when supplemented with octanoate. Upon introduction of a FabF overexpression plasmid into this strain, growth proceeded normally in the absence of fatty acid supplementation. Moreover, this strain had a normal rate of fatty acid synthesis and a normal fatty acid composition. Both the ∆fabH bypass strain that overproduced FabF and the wild type strain incorporated much less exogenous octanoate into long chain phospholipid fatty acids than did the ∆fabH bypass strain. Incorporation of octanoate and decanoate labeled with deuterium showed that these acids were incorporated intact as the distal methyl and methylene groups of the long chain fatty acids.