<Emphasis Type="Italic">Halobacillus locisalis</Emphasis> sp. nov., a halophilic bacterium isolated from a marine solar saltern of the Yellow Sea in Korea

A Gram-positive, motile, endospore-forming and rod-shaped halophilic bacterial strain MSS-155 (KCTC 3788 and KCCM 41687) was isolated from a marine solar saltern of the Yellow Sea in Korea and was subjected to a polyphasic taxonomic study. This organism grew at temperature of 10.0–42.0°C with an optimum of 35°C. Strain MSS-155 grew optimally in the presence of 10% NaCl and did not grow in the absence of NaCl. The cell wall peptidoglycan type of strain MSS-155 was A4 based on l-Orn-d-Asp. Strain MSS-155 was also characterized chemotaxonomically by having menaquinone-7 (MK-7) as the predominant isoprenoid quinone and anteiso-C_15:0 as the major fatty acid. The DNA G+C content was 44.0 mol%. Phylogenetic analysis based on 16S rDNA sequences showed that strain MSS-155 falls within the radiation of the cluster comprising Halobacillus species. Levels of 16S rDNA sequence similarity between strain MSS-155 and the type strains of four Halobacillus species were in the range 97.6–98.8%. Strain MSS-155 exhibited levels of DNA-DNA relatedness of 6.2–11.2% to the type strains of Halobacillus species described previously. On the basis of phenotypic properties, phylogeny, and genomic data, strain MSS-155 should be placed in the genus Halobacillus as a member of a novel species, for which we propose the name Halobacillus locisalis sp. nov.Communicated by W.D. Grant     

Taxonomic Characterization of New Alkaliphilic and Alkalitolerant Methanotrophs from Soda Lakes of the Southeastern Transbaikal Region and description of Methylomicrobium buryatense sp.nov.

Five strains of obligate methanotrophic bacteria (4G, 5G, 6G, 7G and 5B) isolated from bottom sediments of Southeastern Transbaikal soda lakes (pH 9.5–10.5) are taxonomically described. These bacteria are aerobic, Gram-negative monotrichous rods having tightly packed cup-shaped structures on the outer cell wall surface (S-layers) and Type I intracytoplasmic membranes. All the isolates possess particulate methane monooxygenase (pMMO) and one strain (5G) also contains soluble methane monooxygenase (sMMO). They assimilate methane and methanol via the ribulose monophosphate pathway (RuMP). The isolates are alkalitolerant or facultatively alkaliphilic, able to grow at pH 10.5–11.0 and optimally at pH 8.5–9.5. These organisms are obligately dependent on the presence of sodium ions in the growth medium and tolerate up to 0.9–1.4 M NaCl or 1 M NaHCO₃. Although being mesophilic, all the isolates are resistant to heating (80 °C, 20 min), freezing and drying. Their cellular fatty acids profiles primarily consist of C_16:1. The major phospholipids are phosphatidylethanolamine and phosphatidylglycerol. The main quinone is Q-8. The DNA G+C content ranges from 49.2–51.5 mol%. Comparative 16S rDNA sequencing showed that the newly isolated methanotrophs are related to membres of the Methylomicrobium genus. However, they differ from the known members of this genus by DNA-DNA relatedness. Based on pheno- and genotypic characteristics, we propose a new species of the genus Methylomicrobium - Methylomicrobium buryatense sp. nov.     

Isolation and study of two strains ofLeptospirillum-like bacteria from a natural mixed population cultured on a cobaltiferous pyrite substrate

Two strains ofLeptospirillum-like bacteria, L6 and L8, have been isolated from a mixed inoculum, also containingThiobacillus ferrooxidans andT. thiooxidans, cultured for one year with a colbaltiferous pyrite as energy substrate in a 100 I continuous bioleaching laboratory unit. Several physiological properties of the strains are described. The vibrio-shaped microorganisms grew at pH values lower than 1.3. Their growth rate was maximum between 2.5 and 8.0 g l¹ ferrous iron. The optimal growth temperature was 37.5° C. Ferric iron had a stimulative effect on bacterial development up to 8 g l^–1, and growth was as rapid at 14 g l^–1 ferric iron as at 8 g l^–1. The negative influence of cobalt on the final cell concentration was observed at 0.5 g l^–1, but the growth rate was not affected up to 2 g l^–1. The G + C content of strains L8 is 55.6 mol%.     

A numerical taxonomic study of some pigmented bacteria isolated from Organic Lake,an antarctic hypersaline lake

A study was made of a group of moderately halophilic, heterotrophic, pigmented strains isolated from Organic Lake, Antarctica. These strains were Gram-negative, non-motile, had an aerobic metabolism and a mol% G+C content of their DNA in the range 35–41, indicating that they may be members of the Flavobacterium-Cytophaga group. A numerical taxonomic study involving 134 characteristics compared the antarctic strains with reference strains from Flavobacterium, Cytophaga and Flectobacillus. The antarctic strains formed two clusters that did not contain any reference strains suggesting that they may represent two new species of the genus Flavobacterium.     

Taxonomic studies on some gram-positive coryneform hydrogen bacteria

Recently isolated coryneform hydrogen bacteria were investigated under taxonomical aspects. Strains 7 C, RH 10, and 14 g are characterized by the snapping type of cell division, 68.5 to 69.7% GC content, dl-diaminopimelic acid in the cell wall, content of metachromatic granules, weak utilization of sugars and inhibitory effect of citrate. The strains are placed to the group 1—genus Corynebacterium—of the classification of coryneform bacteria of Yamada and Komagata (1972) and the name Corynebacterium autotrophicum sp.nov. is proposed.Strains 11 X and RH 12 are characterized by the bending type of cell division, a GC content of 70.2 and 70.5%, ll-diaminopimelic acid in the cell wall, absence of metachromatic granules, utilization of several sugars and no changes in cell morphology by citrate. The strains have to be placed to group 6 of coryneform bacteria.     

Reclassification of Pichia membranifaciens sensu Kurtzman

Forty strains which were stocked as Pichia membranifaciens sensu Kurtzman and 9 strains stocked as Candida valida, anamorphs of P. membranifaciens, in the Institute for Fermentation, Osaka (IFO) were reclassified based on the data of base composition of nuclear DNA, DNA/DNA hybridization, coenzyme Q system, electrophoretic karyotype, and base sequence of 18S rDNA. P. membranifaciens complex was assigned into 3 groups: (I) P. membranifaciens group, including 25 strains with high DNA homologies to the type strain of P. membranifaciens (72–98%); (II) P. manshurica group, including 18 strains with high DNA homology of 79–95% to the type strain of P. manshurica; and a group including the remaining 6 strains, which had low DNA homology to the above two species. GC content was 42.9–45.3 mol% for the P. membranifaciens group, 40.0–42.0 mol% for the P. manshurica group, and 27.2–44.7 mol% for the remaining group. All three groups had ubiquinone Co Q-7. Of the 6 anomalous strains, IFO 0162 was identified as Pichia deserticola, and IFO 0839 and IFO 0840 were identified as Issatchenkia occidentalis; but IFO 0842, IFO 0843, and IFO 1788 were thought to be unknown strains.     

Characterization of a pyridine-degrading branched Gram-positive bacterium isolated from the anoxic zone of an oil shale column

Summary From the anoxic zone of an oil shale leachate column three pyridine-degrading bacterial strains were isolated. Two strains were Gram-negative facultative anaerobic rods and one strain was a branched Gram-positive bacterium. The branched Gram-positive strain had the best pyridine-degrading ability. This organism was aerobic, non-motile, catalase positive, oxidase negative, and had no flagellum. The G+C content of the DNA was 66.5 mol%. The major menaquinone was MK-8(H₂). The main cellular fatty acids were saturated and monounsaturated straight chains. This organism contained mycolic acid, meso-diaminopimelic acid, arabinogalactan and glycolyl residues in the cell wall. Due to morphological, physiological and chemotaxonomic characteristics this strain was placed in the genus Rhodococcus. The optimum culture conditions were as follows: temperature 32° C, pH 8.0 and 0.1% v/v of pyridine as sole carbon, energy and nitrogen source. Utilization of pyridine by a batch fermentor culture of Rhodococcus sp. was characterized by a specific growth rate of 0.13 h^–1, growth yield of 0.61 mg cell·mg pyridine^–1 and a doubling time of 5.3 h^–1. Offprint requests to: S.-T. Lee     

Yessotoxin detected in mussel (Mytilus californicus) and phytoplankton samples from the U.S. west coast

Yessotoxin (YTX) was detected in an algal sample and two mussel samples (0.07–0.10 μg g⁻¹) collected from Scripps Pier in La Jolla, California during a bloom of Lingulodinium polyedrum. Mussel samples collected from Monterey Bay, California also contained measurable YTX (levels up to 0.06 μg g⁻¹) in samples obtained during a 6-month (weekly) sampling period. Gonyaulax spinifera and L. polyedrum were identified in background concentrations in Monterey Bay during the time of contamination. An algal sample from Washington coastal waters collected during non-bloom conditions also contained YTX, possibly originating from Protoceratium reticulatum.Three strains of L. polyedrum (CCMP1931, CCMP1936, 104A) isolated from southern California coastal waters and one strain of G. spinifera (CCMP409) isolated from Maine were tested for YTX production using two methods, competitive ELISA and liquid chromatography–mass spectrometry (LC–MS). The ELISA method detected YTX in the particulate phase in two of three L. polyedrum strains. The LC–MS method did not detect YTX in the particulate or dissolved phase of any of the strains.To our knowledge, this is the first study to test and confirm YTX in environmental samples from California and Washington coastal waters. It is highly likely that L. polyedrum was responsible for the YTX contamination in the southern California samples. Future research needs to conclusively determine the biological origin(s) of YTX contamination in central California and Washington coastal waters.     

<Emphasis Type="Italic">Arthrobacter ardleyensis</Emphasis> sp. nov., isolated from Antarctic lake sediment and deep-sea sediment

Three psychrotrophic Arthrobacter strains, isolated from Antarctic lake sediment (An24, An25^T) and deep-sea sediment (ZX6) were studied. Their 16S rRNA gene sequences showed highest similarities (97.0–97.9%) with those of A. nicotianae and A. protophormiae. All three strains underwent rod–coccus morphological change, had high mol% G+C content, were aerobic to slightly anaerobic, and grew between 0°C and 30°C, with optimal growth temperature around 25°C. The cell wall peptidoglycan was A4 variant. DNA–DNA hybridization, physiological and chemotaxonomic studies indicated that these three strains constituted a new homogeneous genomic species within the genus Arthrobacter, for which the name Arthrobacter ardleyensis, with the type strain An25^T (CGMCC 1.3685, JCM 12921) was proposed.M. Chen and X. Xiao contributed equally to this paper.     

Identification of moderately halophilic bacteria from Thai fermented fish ( pla-ra ) and proposal of Virgibacillus siamensis sp. nov

Forty-one isolates of moderately halophilic bacteria were isolated from fermented fish (pla-ra) in Thailand. On the basis of their phenotypic and chemotaxonomic characteristics, DNA-DNA relatedness and 16S rRNA gene sequences analyses, they were divided into six groups. The isolates in Group I to V were Gram-positive rod-shaped bacteria. They contained meso-diaminopimelic acid in the cell-wall peptidoglycan and menaquinone with seven isoprene units (MK-7). An isolate in Group VI was a Gram-negative rod-shaped bacterium. The DNA G+C contents of tested strains ranged from 36.5-63 mol%. Ten strains (Group I) were identified as Virgibacillus dokdonensis, 13 isolates (Group II) as V. halodenitrificans, 14 isolates (Group III) as V. marismortui, 1 isolate (Group IV) as Virgibacillus sp., 2 isolates (Group V) as Bacillus vietnamnensis, and 1 isolate (Group VI) as Chromohalobacter salexigens. Isolate MS3-4 in Group IV was closely related to V. carmonensis KCTC 3819(T) (95.9%). This strain contained anteiso-C(15:0) (55.8%) and anteiso-C(17:0) (17.7%) as major cellular fatty acids and had phosphatidylglycerol, diphosphatidylglycerol and an unidentified glycolipid as polar lipids. The DNA G+C content of MS3-4 was 38.0 mol%. The strain from Group IV is proposed as Virgibacillus siamensis sp. nov. and MS3-4(T) is the type strain (JCM 15395(T) =PCU 312(T) =TISTR 1957(T)).     

Regeneration of haploid plants from isolated microspores of asparagus (Asparagus officinalis L.)

High percentages of micro-calli and micro-derived embryos were produced from isolated asparagus microspores at late uninucleate stage on MS liquid medium supplemented with 1.0 mg l^–1 2,4-D and 0.5 mg l^–1 BA. Two types of calli, namely compact callus (CC) and loose callus (LC), were found. Plantlets were regenerated via organogenesis, when these calli were transferred onto MS solid medium supplemented with 1.0 mg l^–1 BA and 0.2 mg l^–1 IBA 6 weeks. Embryos were produced from liquid cultured microspores, or from solid cultured micro-calli. The frequencies of haploid plant production from organogenesis and embryogenesis were compared. Effects of plant growth regulators on callus production, plantlet regeneration, and haploid plant production were tested. The combination of BA 1.0 mg l^–1 and IBA 0.2 mg l^–1 resulted the highest precentage of haploid plant production (7.7% from CC, 4.3% from LC).Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - IBA 3-indolybutyric acid - BA 6-binzyladinine - NAA naphtalene acetic acid - MS Murashige and Skoog     

Identification of lactic acid bacteria from fermented tea leaves (miang) in Thailand and proposals of Lactobacillus thailandensis sp. nov., Lactobacillus camelliae sp. nov., and Pediococcus siamensis sp. nov

Eighteen rod-shaped homofermentatives, six heterofermentatives, and a coccal homofermentative lactic acid bacteria were isolated from fermented tea leaves (miang) produced in the northern part of Thailand. The isolates were placed in a monophyletic cluster consisting of Lactobacillus and Pediococcus species. They were divided into seven groups by phenotypic and chemotaxonomic characteristics, DNA-DNA similarity, and 16S rRNA gene sequences. Groups I to VI belonged to Lactobacillus and Group VII to Pediococcus. All of the strains tested produced DL-lactic acid but those in Group IV produced L-lactic acid. The strains tested in Groups I, II and V had meso-diaminopimelic acid in the cell wall. Six strains in Group I were identified as Lactobacillus pantheris; five strains in Group II as Lactobacillus pentosus; and four strains in Group V as Lactobacillus suebicus. Two strains in Group VI showed high DNA-DNA similarity for each other and MCH4-2 was closest to Lactobacillus fermentum CECT 562(T) with 99.5% of 16S rRNA gene sequence similarity. Five strains in Group III are proposed as Lactobacillus thailandensis sp. nov., and MCH5-2(T) (BCC 21235(T)=JCM 13996(T)=NRIC 0671(T)=PCU 272(T)) is the type strain which has 49 mol% G+C of DNA. Two strains in Group IV are proposed as Lactobacillus camelliae sp. nov., and the type strain is MCH3-1(T) (BCC 21233(T)=JCM 13995(T)=NRIC 0672(T)=PCU 273(T)) which has 51.9 mol% G+C of DNA. One strain in Group VII is proposed as Pediococcus siamensis sp. nov., and MCH3-2(T) (BCC 21234(T)=JCM 13997(T)=NRIC 0675(T)=PCU 274(T)) is the type strain which has 42 mol% G+C of DNA.     

Structural variation in the glycoinositolphospholipids of different strains ofTrypanosoma cruzi

The structures of the glycoinositolphospholipids (GIPLs) from five strains of the protozoan parasiteTrypanosoma cruzi have been determined. Two series of structures were identified, all but one containing the same Man₄(AEP)GlcN-Ins-PO₄ core. Series 1 oligosaccharides are substituted at the third mannose distal to inositol (Man 3) by ethanolamine-phosphate or 2-aminoethylphosphonic acid, as are some glycosyl-phosphatidylinositol-protein anchors ofT. cruzi. The core can be further substituted by terminal (1–3)-linked -galactofuranose units. In contrast, Series 2 oligosaccharides do not have additional phosphorus-containing groups attached to Man 3, the latter being substituted instead by a single side chain unit of -galactofuranose. Series 1 oligosaccharides are present in all strains (G, G-645, Tulahuen CL, and Y) whereas Series 2 structures are present mainly in CL and Y strains. The lipid moiety in the GIPLs from the G, G-645 and Tulahuen strains is predominantly ceramide, as reported for the Y strain, whilst that from the CL strain is a mixture of ceramide and alkylacylglycerol species. The lipid moiety of the GIPLs, and probably also the phosphoinositol-oligosaccharide structures may play an important immunomodulatory role in infection byT. cruzi.Abbreviations GIPL glycoinositolphospholipid - LPPG lipopeptidophosphoglycan - GPI glycosylphosphatidylinositol - AEP 2-aminoethylphosphonic acid - PI phosphoinositol - GC gas-liquid chromatography - MS mass spectrometry - FAB fast atom bombardment - NMR nuclear magnetic resonance - DQF-COSY double quantum-filtered correlation spectroscopy - TOCSY total correlation spectroscopy - ROESY rotating frame nuclear Overhauser enhancement spectroscopy - EtNP ethanolaminephosphate - HMQC heteronuclear multiple quantum coherence - Man mannose - Galf galactofuranose - GlcN glucosamine - Ins inositol - InsP inositolphosphate - Man 3 third mannose distal to inositol - NOE nuclear Overhauser effect - [M+H]⁺ protonated molecule - [M–H]^– deprotonated molecule - RMM relative molecular mass (monoisotopic)     

Psychrotrophic,lactic acid-producing bacteria from anoxic waters in Ace Lake,Antarctica; Carnobacterium funditum sp. nov. and Carnobacterium alterfunditum sp. nov.

Heterofermentative, lactic acid-producing, gram-positive, motile bacteria were isolated from the waters of Ace Lake, Antarctica. All strains produced virtually only l(+)lactic acid from d(+)glucose. d(–)ribose was fermented to lactic, acetic, and formic acids, and ethanol. Cell walls contained meso-diaminopimaleic acid. The strains did not grow at 30°C and were psychrotrophic. Whole cells contained 18:1cis 9 as a major component of their fatty acids. At 20°C, the strains grew better anaerobically than aerobically and all strains lacked catalase, oxidase and respiratory lipoquinones. DNA that coded for most of the 16S rRNA gene of one of the strains was amplified by the polymerase chain reaction and sequenced. The strain was phylogenetically most closely related to Carnobacterium mobile (K_nuc=0.0214). The isolates separated into two phenotypes. DNA/DNA homology studies determined on a representative from each phenotype showed low homology between the phenotypes (38±8%), and with Carnobacterium mobile (26±2%, 34±2%). Carnobacterium funditum sp. nov. produced acid from mannitol, trehalose, but not amygdalin. The G+C content of the DNA was 32–34%, and the Type strain is DSM 5970 (=ACAM 312). Carnobacterium alterfunditum sp. nov. produced acid weakly from amygdalin but not from mannitol or trehalose. The G+C content was 33–34%, and the Type strain is DSM 5972 (=ACAM 313).     

Thiocapsa halophila sp. nov., a new halophilic phototrophic purple sulfur bacterium

A new phototrophic sulfur bacterium has been isolated from a red layer in a laminated mat occurring underneath a gypsum crust in the mediterranean salterns of Salin-de-Giraud (Camargue, France). Single cells were coccus-shaped, non motile, without gas vacuoles and contained sulfur globules. Bacteriochlorophyll a and okenone were present as major photosynthetic pigments. These properties and the G+C content of DNA (65.9–66.6 mol% G+C) are typical characteristics of the genus Thiocapsa. However, the new isolate differs from known species in the genus, particularly in NaCl requirement (optimum, 7% NaCl; range, 3–20% NaCl) and some physiological characteristics. Therefore, a new species is proposed, Thiocapsa halophila, sp. nov.Dedicated to Prof. Dr. Norbert Pfennig in occasion of his 65th birthday     

Stimulatory effect of menaquinone-7 (vitamim K2) on osteoblastic bone formation in vitro

Menaquinone-7, which is vitamin K₂ (menatetrenone) with seven isoprene units, is highly contained in the fermented soybean. The effect of menaquinone-7 (MK-7) on osteoblastic bone formation was investigated. Femoral-diaphyseal and metaphyseal tissues of young male rats (4 weeks old) were cultured for 48 h in a medium containing either vehicle or MK-7 (10^–7–10^–5 M). Calcium content, alkaline phosphatase activity, and deoxyribonuclic acid (DNA) content in the diaphyseal and metaphyseal tissues was significantly increased in the presence of MK-7 (10^–6 and 10^–5 M). The effect of MK-7 in increasing the diaphyseal and metaphyseal calcium content and alkaline phosphatase activity was completely prevented in the presence of cycloheximide (10^–6 M), an inhibitor of protein synthesis. Moreover, osteoblastic MC3T3-E1 cells after subculture were cultured for 24 h in a serum-free medium containing MK-7 (10^–7–10^–5 M). Protein content, alkaline phophatase activity, osteocalcin and DNA content in the cells was significantly increased in the presence of MK-7 (10^–6 and 10^–5 M). The effect of MK-7 in increasing protein content, alkaline phosphatase activity, and osteocalcin production in the cells was completely blocked by cycloheximide. This study demonstrates that MK-7 has an anabolic effect on bone tissue and osteoblastic MC3T3-E1 cells in vitro, suggesting that the compound can stimulate osteoblastic bone formation.     

Poly(hydroxyalkanoate) synthase genotype and PHA production of Pseudomonas corrugata and P. mediterranea

A collection of Pseudomonas corrugata and P. mediterranea strains, two closely related species, was evaluated for the presence and variability of pha loci. Using PCR methods that specifically amplify segments of medium-chain-length poly(hydroxyalkanoate) (mcl-PHA) synthase genes, we demonstrated the presence of phaC1 and phaC2 in all P. mediterranea strains tested and in six out of 56 strains of P. corrugata screened. The remaining 50 strains of P. corrugata yielded only the phaC2 subgene fragment on detection by a combined PCR-restriction endonuclease analysis method or a semi-nested PCR-amplification approach. A Southern hybridization study on a representative strain from this group, however, indicated the presence of the phaC1 gene. Nucleic acid sequences of the subgene phaC fragments of the representative strains from the three groups showed an overall similarity ranging from 95% to 100%. The major repeat-unit monomers of the mcl-PHAs isolated from these selected strains are -hydroxyoctanoate (33–47 mol%) and -hydroxydecanoate (26–36 mol%). These results differentiate for the first time the strains of P. corrugata into two pha-distinguishable groups. This study also documents for the first time the production of mcl-PHA in P. mediterranea.     

A thermophilic green sulfur bacterium from New Zealand hot springs,Chlorobium tepidum sp. nov.

Thermophilic green sulfur bacteria of the genus Chlorobium were isolated from certain acidic high sulfide New Zealand hot springs. Cells were Gram-negative nonmotile rods of variable length and contained bacteriochlorophyll c and chlorosomes. Cultures of thermophilic chlorobia grew only under anaerobic, phototrophic conditions, either photoautotrophically or photoheterotrophically. The optimum growth temperature for the strains of thermophilic green sulfur bacteria isolated was 47–48°C with generation times of about 2 h being observed. The upper temperature limit for growth was about 52°C. Thiosulfate was a major electron donor for photoautotrophic growth while sulfide alone was only poorly used. N₂ fixation was observed at 48°C and cell suspensions readily reduced acetylene to ethylene. The G+C content of DNA from strains of thermophilic chlorobia was 56.5–58.2 mol% and the organisms positioned phylogenetically within the green sulfur bacterial branch of the domain Bacteria. The new phototrophs are described as a new species of the genus Chlorobium, Chlorobium tepidum.This paper is dedicated to Professor Norbert Pfennig on the occasion of his 65th birthday     

α,ω-Dicarboxylic acid accumulation by acyl-CoA oxidase deficient mutants of <Emphasis Type="Italic">Yarrowia lipolytica</Emphasis>

α,ω-Dicarboxylic acid accumulation from alkanes and alkane degradation intermediates was investigated using Yarrowia lipolytica wild type strain W29 as well as a double, a triple and a quadruple POX-deleted strains. Six genes, POX1 through POX6, encode six acyl-CoA oxidase isozymes in Y. lipolytica. All the strains accumulated dodecanedioic acid (5–20 mg ml⁻¹) from the diterminal functionalised 1,12-dodecane diol and 12-hydroxdodecanoic acid. The quadruple-deleted strain was the only strain that was able to accumulate dioic acids from C16 alkanol and monocarboxylic acid as well as from C12, C14 and C16 alkanes (maximum 8 mg ml⁻¹ from dodecane).     

<Emphasis Type="Italic">Alkalimonas amylolytica</Emphasis> gen. nov., sp. nov., and<Emphasis Type="Italic"> Alkalimonas delamerensis</Emphasis> gen. nov., sp. nov., novel alkaliphilic bacteria from soda lakes in China and East Africa

Two related novel alkaliphilic and slightly halophilic bacteria are described. They are strain N10 from Lake Chahannor in China and strain 1E1 from Lake Elmenteita in East Africa. Both strains are strictly aerobic, heterotrophic, alkaliphilic, mesophilic, and require NaCl for growth. The optimal conditions for growth were at pH 10–10.5 and 2–3% (w/v) NaCl. Cells of both strains were Gram-negative, rod-shaped, non-spore-forming, and motile with a single polar flagellum. Cellular fatty acids in both strains were predominantly saturated and mono-unsaturated straight-chain fatty acids (16:0, 16:17c and 18:17c). The major isoprenoid quinone of both strains was Q8. The major polar lipids are phosphatidylglycerol, diphosphatidylglycerol, phosphatidylglycerol phosphate and phosphatidylethanolamine. The guanine plus cytosine (G+C) content of the DNA was 52.5 mol% and 55.4 mol%, respectively. Phylogenetic analysis revealed that the two strains formed a distinct lineage within the gamma-3 subclass of the Proteobacteria. The strains shared a 16S rDNA sequence similarity of 96.1% and showed less than 93.7% of sequence similarity to any other known species. Based on polyphasic data, the two strains were differentiated from currently recognized genera and represent a new genus, Alkalimonas gen. nov., with two species, Alkalimonas amylolytica sp. nov. (type strain is N10^T = AS 1.3430) and Alkalimonas delamerensis sp. nov. ( type strain is 1E1^{P, T} = CBS 391.94). The GenBank accession numbers for the 16S rRNA gene sequence of strains N10 and 1E1 are AF250323 and X92130, respectively.Communicated by K. Horikoshi