Wen Dar Jean

Alterococcus agarolyticus, gen.nov., sp.nov., a halophilic thermophilic bacterium capable of agar degradation

Five strains of facultatively anaerobic moderately thermophilic bacteria were isolated from two hot springs in the intertidal zone of Lutao, Taiwan. They produced extracellular agarase on agar medium, yielding reducing sugars and organic acids as the end products under either aerobic or anaerobic conditions. The growth temperature range was approximately 38-58 degrees C with an optimal temperature of about 48 degrees C. The five strains tolerated a relatively narrow pH range from 7.0 to 8.5. They were Gram-negative halophiles growing optimally at 2.0-2.5% NaCl (ca. 0.34-0.43 M). They were capable of anaerobic growth by fermenting glucose and producing various organic acids such as butyrate, propionate, formate, lactate, and acetate. Cells grown in liquid medium were motile monotrichous cocci, normally 0.8-0.9 micron in diameter. They possessed saturated anteiso-15-carbon acid (anteiso-C15:0) as the most abundant cellular fatty acid (46.0-51.3 mo1%) and had G + C contents ranging from 65.5 to 67.0 mo1%. They are the first thermophiles found to degrade agar and also the first halophilic thermophilic bacteria known to be capable of both aerobic and anaerobic fermentative growth. These bacteria are considered to represent a new genus that we named Alterococcus, and Alterococcus agarolyticus is the type species.

Simiduia agarivorans gen. nov., sp. nov., a marine, agarolytic bacterium isolated from shallow coastal water from Keelung, Taiwan

A Gram-negative, heterotrophic, agarolytic, marine bacterium, designated strain SA1T, was isolated from a seawater sample collected in the shallow coastal region of Keelung, Taiwan. Cells were straight to slightly curved rods. Nearly all of the cells were non-motile and non-flagellated during the exponential phase of growth in broth cultures; a few cells (<1 %) were motile and were considered to have monotrichous flagella. The isolate required NaCl for growth and grew optimally at 30-35 degrees C and 2-3 % (w/v) NaCl. It grew aerobically and was incapable of anaerobic growth by fermentation of glucose or other carbohydrates. However, anaerobic growth could be achieved by reduction of nitrate to nitrite. Polar lipids comprised phosphatidylethanolamine (71.8 %), diphosphatidylglycerol (12.7 %), phosphatidylglycerol (12.2 %) and phosphatidylserine (3.3 %). Isoprenoid quinones consisted of Q-10 (87.5 %), MK-9 (6.6 %) and MK-7 (5.9 %). Major cellular fatty acids were C16 : 1 omega 7c and/or iso-C15 : 0 2-OH (28.6 %), C17 : 1 omega 8c (22.8 %), C16 : 0 (14.5 %), C18 : 1 omega 7c (11.0 %) and C17 : 0 (6.4 %). The DNA G+C content was 55.6 mol%. Phylogeny based on 16S rRNA gene sequence analysis showed that strain SA1T formed a distinct lineage within the class Gammaproteobacteria. Strain SA1T was related most closely to Teredinibacter turnerae, Cellvibrio spp., Saccharophagus degradans, Pseudomonas spp. and Microbulbifer spp., strains of these species sharing <93 % 16S rRNA gene sequence similarity with strain SA1T. The phylogenetic data and those from physiological, morphological and chemotaxonomic characterizations indicated that strain SA1T represents a novel species and genus, for which the name Simiduia agarivorans gen. nov., sp. nov. is proposed. The type strain is SA1T (=BCRC 17597T=JCM 13881T).

Pseudidiomarina marina sp. nov. and Pseudidiomarina tainanensis sp. nov. and reclassification of Idiomarina homiensis and Idiomarina salinarum as Pseudidiomarina homiensis comb. nov. and Pseudidiomarina salinarum comb. nov., respectively.

Two Gram-negative strains of heterotrophic, aerobic, marine bacteria, designated PIM1T and PIN1T, were isolated from seawater samples collected from the shallow coastal region of An-Ping Harbour, Tainan, Taiwan. Cells grown in broth cultures were straight rods and non-motile. The two isolates required NaCl for growth and grew optimally at 30-35 degrees C and 2-5 % NaCl. They grew aerobically and were not capable of anaerobic growth by fermentation of glucose or other carbohydrates. The cellular fatty acids were predominantly iso-branched, with iso-C(15 : 0) (17.0-21.4 %), iso-C(17 : 0) (18.2-21.0 %) and iso-C(17 : 1)omega9c (15.7-16.6 %) as the most abundant components. The predominant isoprenoid quinone was Q-8 (95.2-97.1 %). Strains PIM1T and PIN1T had DNA G+C contents of 46.6 and 46.9 mol%, respectively. Phylogeny based on 16S rRNA gene sequences and DNA-DNA hybridization, together with data from physiological, morphological and chemotaxonomic characterizations, indicated that the two isolates should be classified as representatives of two novel species of the genus Pseudidiomarina of the family Idiomarinaceae, for which the names Pseudidiomarina marina sp. nov. (type strain PIM1T=BCRC 17749T=JCM 15083T) and Pseudidiomarina tainanensis sp. nov. (type strain PIN1T=BCRC 17750T=JCM 15084T) are proposed. In addition, based on the characterization data obtained in this study, it is proposed that Idiomarina homiensis and Idiomarina salinarum should be reclassified as Pseudidiomarina homiensis comb. nov. and Pseudidiomarina salinarum comb. nov., respectively.

Aliidiomarina taiwanensis gen. nov., sp. nov., isolated from shallow coastal water.

A Gram-negative, heterotrophic, aerobic, marine bacterium, designated AIT1(T), was isolated from a seawater sample collected in the shallow coastal region of Bitou Harbour, New Taipei City, Taiwan. Cells grown in broth cultures were straight or slightly curved rods that were motile by means of a single polar flagellum. Strain AIT1(T) required NaCl for growth, grew optimally at 30-40°C and with 1.5-5.0% NaCl, and was incapable of anaerobic growth by fermentation of glucose or other carbohydrates. The isoprenoid quinones consisted of Q-8 (95.2%) and Q-9 (4.8%). The major polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The cellular fatty acids were predominantly iso-branched and included iso-C(17:0) (26.5%), summed feature 9 (comprising iso-C(17:1)ω9c and/or 10-methyl C(16:0); 25.9%) and iso-C(15:0) (20.5%). The DNA G+C content was 51.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain AIT1(T) formed a distinct lineage within the class Gammaproteobacteria and was most closely related to members of the genus Idiomarina in the family Idiomarinaceae (91.5-93.9% 16S rRNA gene sequence similarity). The phylogenetic data, together with chemotaxonomic, physiological and morphological data, revealed that the isolate should be classified as a representative of a novel species in a new genus in the family Idiomarinaceae, for which the name Aliidiomarina taiwanensis gen. nov., sp. nov. is proposed. The type strain is AIT1(T) (=JCM 16052(T)=BCRC 80035(T)=NCCB 100321(T)).

Aliagarivorans marinus gen. nov., sp. nov. and Aliagarivorans taiwanensis sp. nov., facultatively anaerobic marine bacteria capable of agar degradation

Two agarolytic strains of Gram-negative, heterotrophic, facultatively anaerobic, marine bacteria, designated AAM1T and AAT1T, were isolated from seawater samples collected in the shallow coastal region of An-Ping Harbour, Tainan, Taiwan. Cells grown in broth cultures were straight rods that were motile by means of a single polar flagellum. The two isolates required NaCl for growth and grew optimally at about 25-30 degrees C, in 2-4% NaCl and at pH 8. They grew aerobically and could achieve anaerobic growth by fermenting D-glucose or other sugars. The major isoprenoid quinone was Q-8 (79.8-92.0%) and the major cellular fatty acids were summed feature 3 (C16:1omega7c and/or iso-C15:0 2-OH; 26.4-35.6%), C18:1omega7c (27.1-31.4%) and C16:0 (14.8-16.3%) in the two strains. Strains AAM1T and AAT1T had DNA G+C contents of 52.9 and 52.4 mol%, respectively. The two strains had a 16S rRNA gene sequence similarity of 98.6% and shared 84.9-92.4% sequence similarity with the type strains of Agarivorans albus (91.2-92.4%), eight Alteromonas species (84.9-87.1%), two Aestuariibacter species (86.0-87.0%), Bowmanella denitrificans (86.1-86.7%), eight Glaciecola species (85.0-87.9%) and Salinimonas chungwhensis (85.9-86.1%). Despite their high sequence similarity, strains AAM1T and AAT1T had a DNA-DNA relatedness value of only 4.5%. The data obtained from these polyphasic taxonomic studies revealed that the two agarolytic isolates could be classified as representatives of two novel species in a new genus, Aliagarivorans gen. nov., with Aliagarivorans marinus sp. nov. [type strain is AAM1T (=BCRC 17888T=JCM 15522T)] as the type species and Aliagarivorans taiwanensis sp. nov. [type strain is AAT1T (=BCRC 17889T=JCM 15537T)] as a second species.

Reclassification of [Glaciecola] lipolytica and [Aestuariibacter] litoralis in Aliiglaciecola gen. nov., as Aliiglaciecola lipolytica comb. nov. and Aliiglaciecola litoralis comb. nov., respectively.

Following phylogenetic analysis based on 16S rRNA gene sequences, together with DNA G+C contents and differential chemotaxonomic and physiological characteristics, a new genus with the name Aliiglaciecola gen. nov. is proposed to more appropriately accommodate two recognized species of the genera Glaciecola and Aestuariibacter. Accordingly, [Glaciecola] lipolytica and [Aestuariibacter] litoralis should be reassigned to the novel genus as Aliiglaciecola lipolytica comb. nov. (type strain, E3(T) = JCM 15139(T) = CGMCC 1.7001(T)) and Aliiglaciecola litoralis comb. nov. (type strain, KMM 3894(T) = JCM 15896(T) = NRIC 0754(T)), respectively. Aliiglaciecola lipolytica is proposed as the type species of this new genus. Physiologically, the combined characteristics of positive reactions for nitrate reduction and growth at 4 °C and 36 °C distinguish the new genus from the genera Aestuariibacter and Glaciecola by one to three traits. Moreover, the new genus is also distinguished from the genus Glaciecola by the fatty acid profile and distinguished from the genus Aestuariibacter by the differences of major isoprenoid quinone (MK-7 vs Q-8) and DNA G+C content (40.8-43.0 mol% vs 48.0-54.0 mol%).

Kangiella taiwanensis sp. nov. and Kangiella marina sp. nov., marine bacteria isolated from shallow coastal water.

Two Gram-negative, heterotrophic, aerobic, marine bacteria, designated strains KT1(T) and KM1(T), were isolated from seawater samples collected from the shallow coastal regions of northern Taiwan. Cells grown in broth cultures were non-flagellated rods. NaCl was required for growth. Optimal growth occurred with 2-5 % NaCl, at 25-30 °C and at pH 8. They grew aerobically and were not capable of anaerobic growth by fermenting D-glucose or other carbohydrates. Q-8 was the only isoprenoid quinone. The major polar lipid detected in strain KT1(T) was phosphatidylmonomethylethanolamine, whereas those detected in KM1(T) were phosphatidylmonomethylethanolamine, phosphatidyldimethylethanolamine and an unidentified phospholipid. Cellular fatty acids were nearly all iso-branched, with iso-C(15 : 0) as the most abundant component (54.6-57.2 % of the total). Strains KT1(T) and KM1(T) had DNA G+C contents of 43.9 and 46.3 mol%, respectively. The two strains shared 98.1 % 16S rRNA gene sequence similarity; levels of similarity with the type strains of species of the genus Kangiella were 95.6-98.4 %. Data from the present taxonomic study conducted using a polyphasic approach revealed that the isolates could be classified as representatives of two novel species of the genus Kangiella, for which the names Kangiella taiwanensis sp. nov. (type strain KT1(T) = BCRC 80330(T) = JCM 17727(T)) and Kangiella marina sp. nov. (type strain KM1(T) = BCRC 80329(T) = JCM 17728(T)) are proposed.

Spongiibacter taiwanensis sp. nov., a marine bacterium isolated from aged-seawater.

A Gram-reaction-negative, heterotrophic, marine bacterium, designated strain SPT1T, was isolated from an aged seawater sample which was collected from the shallow coastal region of Nanya, Keelung, Taiwan and stored at room temperature for more than 7 years. Strain SPT1T was a motile rod which exhibited monotrichous flagellation. It required NaCl for growth and exhibited optimal growth at 30-35 °C, 1-3 % NaCl and pH 7-8. The strain was a strictly aerobic bacterium, incapable of anaerobic growth by nitrate reduction or denitrification, or by fermenting glucose or other carbohydrates. Cellular fatty acids were dominated by C16 : 1ω7c and/or C16 : 1ω6c (23.4 %), C17 : 1ω8c (18.1 %), C16 : 0 (8.5 %), C18 : 1ω7c (8.4 %) and C10 : 0 3-OH (6.3 %). The predominant isoprenoid quinone was Q-8. Polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol and phosphatidic acid. The DNA G+C content was 57.9 mol%. Phylogeny based on 16S rRNA gene sequences showed that strain SPT1T formed a distinct species-level lineage within the genus Spongiibacter of the class Gammaproteobacteria and shared sequence similarities of 94.4-96.2 % with Spongiibacter marinusand Spongiibacter tropicus, the only two species of the genus Spongiibacterwith validly published names. The 16S rRNA gene sequence similarities between strain SPT1T and other species were less than 93.1 %. Polyphasic taxonomic data obtained in this study indicated that strain SPT1T could be classified as a novel species of the genus Spongiibacter, for which the name Spongiibacter taiwanensis sp. nov. is proposed. The type strain is SPT1T (=JCM 31012T=BCRC 80916T).

Tagaea marina gen. nov., sp. nov., a marine bacterium isolated from shallow coastal water

A Gram-negative, heterotrophic, marine bacterium, designated strain TT1T, was isolated from seawater collected from the shallow coastal region of Anping Harbour, Tainan, Taiwan. Cells grown in broth cultures were straight rods that were motile by means of a single polar flagellum. The isolate required NaCl for growth and exhibited optimal growth at 30-35 °C, 2-4 % NaCl and pH 7-8. Strain TT1T grew aerobically and was not capable of anaerobic growth by fermentation of glucose or other carbohydrates. Q-10 was the sole major isoprenoid quinone. Cellular fatty acids were dominated by C18 : 1ω7c (47.5 %), C18 : 1 2-OH (16.3 %) and C19 : 0ω8c cyclo (10.6 %). The DNA G+C content was 56.4 mol%. Phylogeny based on 16S rRNA gene sequences showed that strain TT1T formed a distinct genus-level lineage in the family Rhodospirillaceae of the class Alphaproteobacteria and exhibited the highest sequence similarity with species of the genera Thalassobaculum (89.9-90.0 % 16S rRNA gene sequence similarity), Oceanibaculum (89.4-89.9 %) and Nisaea (89.1-89.7 %). Strain TT1T could be distinguished from species of these phylogenetically closest genera based on differences in DNA G+C contents (56.4 mol% vs 60.0-68.0 mol%), fatty acid profiles and some physiological characteristics. On the basis of the polyphasic taxonomic data from this study, strain TT1T is considered to represent a novel species of a new genus in the family Rhodospirillaceae, for which the name Tagaea marina gen. nov., sp. nov. is proposed. The type strain of the type species is TT1T ( = JCM 18659T = BCRC 80493T).