bacteriochlorophylls and rhodopin

Strain JA878T was purified from a photoheterotrophic enrichment obtained from a sediment sample of a brown pond near Nari Salt Pan, Bhavnagar, Gujarat, India. Cells of the isolate were coccoid, motile by means of single polar flagellum and Gram-stain-negative. The internal photosynthetic membrane architecture was vesicular. Strain JA878T contained bacteriochlorophyll a and spirilloxanthin series of carotenoids with rhodopin (>85 %) as the major component. Strain JA878T grew optimally at pH 10-11, and had no requirement for NaCl (tolerated up to 6 %, w/v) or vitamins for growth. C16 : 1ω7c/C16 : 1ω6c, C18 : 1ω7c/C18 : 1ω6c and C16 : 0 were identified as the major fatty acids (>10 %). Phosphatidylglycerol, phosphatidylethanolamine, aminophospholipid and an unknown polar lipid were identified. Q8 was the predominant quinone system in strain JA878T. The DNA G+C content was 62.4 mol%. Highest 16S rRNA gene sequence similarity through EzTaxon-based blast analysis of strain JA878T was found with the type strains of Thiorhodococcus fuscus (99 %), Thiorhodococcus kakinadensis (98.6 %), Thiohalobacter thiocyanaticus (98.4 %), Thiophaeococcus fuscus (97.3 %) and other members of the class Gammaproteobacteria (<97.3 %), revealing a close affiliation to the genera Thiorhodococcus, Thiohalobacter and Thiophaeococcus. However, the phylogenetic treeing firmly placed the strain in the genus Thiorhodococcus. Phenotypic and chemotaxonomic evidence supported the affiliation of strain JA878T to the genus Thiorhodococcus and not to Thiohalobacter, Thiophaeococcus or other known genera of Chromatiaceae. Distinct physiological, genotypic and chemotaxonomic differences indicate that strain JA878T represents a novel species of the genus Thiorhodococcus, for which the name Thiorhodococcus alkaliphilus sp. nov. is proposed. The type strain is JA878T (=KCTC 15531T=JCM 31245T).

Topics: Bacterial Typing Techniques; Bacteriochlorophyll A; Carotenoids; DNA, Bacterial; Fatty Acids; Geologic Sediments; India; Phospholipids; Phylogeny; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Thiotrichaceae; Vitamin K 2; Water Microbiology

A brown, moderately halophilic, photoautotrophic bacterium designated strain JA363T was purified from a photoheterotrophic enrichment obtained from sediment from Chilika lagoon, Odisha, India. Cells of the isolate were coccoid, motile by means of single polar flagellum and Gram-stain-negative. Strain JA363T had an obligate requirement for NaCl and could tolerate up to 7 % (w/v) NaCl. Strain JA363T had complex growth factor requirements. Internal photosynthetic membranes were present as vesicles. Strain JA363T contained bacteriochlorophyll a and spirilloxanthin series carotenoids with rhodopin as a major (>85 %) component. C16 : 1ω7c/C16 : 1ω6c, C18 : 1ω7c and C16 : 0 were the major fatty acids and phosphatidylglycerol and phosphatidylethanolamine were the major polar lipids. Q8 was the predominant quinone system of strain JA363T. The DNA G+C content was 64 mol%. The highest 16S rRNA gene sequence similarity of strain JA363T was found with the type strains of Thiorhodococcus kakinadensis (98.7 %), Thiohalobacter thiocyanaticus (98.2 %), Thiophaeococcus fuscus (97.4 %) and Thiorhodococcus bheemlicus (96.3 %). However, the phylogenetic trees generated firmly placed strain JA363T in the genus Thiorhodococcus, which was further supported by phenotypic and chemotaxonomic evidence. Consequently, strain JA363T is described as representing a novel species of the genus Thiorhodococcus as Thiorhodococcus fuscus sp. nov. The type strain is JA363T ( = KCTC 5701T = NBRC 104959T).

Topics: Bacterial Typing Techniques; Bacteriochlorophyll A; Base Composition; Carotenoids; Chromatiaceae; DNA, Bacterial; Fatty Acids; India; Phospholipids; Phylogeny; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Vitamin K 2

A reddish-brown bacterium, designated strain JA318(T), was purified from a photoheterotrophic enrichment culture obtained from the rhizosphere soil of paddy. Cells of strain JA318(T) are spiral shaped, Gram-stain-negative and motile by means of amphitrichous flagella. Strain JA318(T) has no NaCl requirement for growth but can tolerate up to 1.5 % (w/v) NaCl. Internal photosynthetic membranes are present as lamellar stacks. Photoorganoheterotrophy is the only growth mode observed. Strain JA318(T) contains bacteriochlorophyll a, lycopene and rhodopin as major carotenoids. Thiamine, niacin and para-aminobenzoic acid (PABA) are required as growth factors. Major fatty acids are C18 : 1ω7c and C16 : 0. Ubiquinone-8 and rhodoquinone-8 are the observed quinones. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and an unidentified aminolipid are the major polar lipids in strain JA318(T). Phylogenetic analysis based on 16S rRNA gene sequences showed that the strain JA318(T) clustered with species of the genus Rhodospirillum which belongs to the class Alphaproteobacteria. The highest sequence similarity of strain JA318(T) was found with Rhodospirillum sulfurexigens JA143(T) (99.9 %). The DNA-DNA reassociation values of strain JA318(T) with Rsp. sulfurexigens JA143(T) and Rhodospirillum photometricum DSM 122(T) were 52 ± 2 % and 45 ± 1 %, respectively. The genomic DNA G+C content of strain JA318(T) was 60.2 mol%. Based on the morphological, physiological, chemotaxonomical and molecular evidence, strain JA318(T) is significantly different from the type strains of species of the genus Rhodospirillum, of the family Rhodospirillaceae, and it is proposed that the strain be classified as a representative of a novel species for which the name Rhodospirillum oryzae sp. nov. is proposed. The type strain is JA318(T) (= KCTC 5960(T) = NBRC 107573(T)).

Topics: Bacterial Typing Techniques; Bacteriochlorophyll A; Base Composition; Carotenoids; DNA, Bacterial; Fatty Acids; India; Lycopene; Molecular Sequence Data; Nucleic Acid Hybridization; Oryza; Phylogeny; Rhizosphere; Rhodospirillum; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Soil Microbiology; Ubiquinone

Two strains (JA480(T) and JA481) of phototrophic alphaproteobacteria were isolated from sediment samples collected from brackish water near Nagapattinam, India. They were Gram-negative, vibrioid cells containing bacteriochlorophyll a and rhodopin as major photosynthetic pigments. Most cells of both strains were non-flagellated; 1 % of cells showed two monopolar flagella. Cells showed positive phototaxis. Both strains showed chimeric intracellular photosynthetic membranes, where both lamellar stacks and vesicles were present together in a single cell. The major fatty acids were C(18 : 1)ω7c and C(16 : 0) in both strains. The genomic G+C content was 67.2-68.8 mol% and the two strains were closely related (mean DNA-DNA hybridization >85 %). 16S rRNA gene sequence comparisons indicated that the isolates represent members of the Rhodospirillaceae within the class Alphaproteobacteria. According to the sequence comparison data, strain JA480(T) is positioned distinctly outside the group formed by the phototrophic genera Rhodospirillum, Rhodocista, Phaeospirillum, Rhodovibrio, Rhodospira and Roseospira, with only 80-92 % 16S rRNA gene sequence similarity. Distinct morphological, physiological and genotypic differences from previously described taxa support the classification of this isolate as a representative of a novel species in a new genus, for which the name Phaeovibrio sulfidiphilus gen. nov., sp. nov. is proposed. The type strain of Phaeovibrio sulfidiphilus is JA480(T) ( = KCTC 5825(T)  = NBRC 106163(T)  = DSM 23193(T)).

Topics: Alphaproteobacteria; Bacteriochlorophyll A; Base Composition; Carotenoids; Cluster Analysis; DNA, Bacterial; DNA, Ribosomal; Fatty Acids; Flagella; India; Light; Locomotion; Molecular Sequence Data; Nucleic Acid Hybridization; Phylogeny; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Water Microbiology

To exploit resources of purple sulfur bacteria in China and further investigate its response mechanism to ecological environment of mangrove.. Repeated agar shake dilution method, microscope techniques, UV-Vis absorption spectra, thin layer chromatography, HPLC and MS were used.. We isolated a purple sulfur bacterium, designated as strain YL28, from a intertidal sediment sample collected from inshore mangrove near Luoyang Bridge of Quanzhou city, Fujian Province of China. Cells were ovoid to rod shaped, 0.5 microm - 1 microm x 2 microm - 3 microm. Color of cell suspensions was reddish-brown. It possessed vesicular intracytoplasmic membrane structures, contained rhodopin and phytylated bacteriochlorophyll a as well as the other two novel bacteriochlorophyll a intermediates. The optimum growth was at 2% - 3.5% NaCl, pH 5.7 - 6.7 and 20 degrees C - 35 degrees C. Photoautotrophically growth anaerobically in the light with sulphide, sulphur, thiosulfate, sulfite as electron donor. Globules of S(0) distributed inside the cells. Photoheterotrophic growth with various organic substrates, especially citrate, glucose, sucrose, fructose and propanol in the presence of sulfide. Nitrogen sources: ammonium salts, N2, urea, glutamate, nitrate and nitrite. Vitamins were not required. Qualitative assessment of IC50 values of chloromycetin, cefazolin, benzene, hydroxy biphenyl, enrofloxacin, acetamiprid, mercuric chloride and cadmium chloride were 70, 100, 20, 20, 3, 170, 5 mg/L and 25 mg/L, respectively.. Based on phenotype characteristics and 16S rRNA gene sequence similarity of 99% to M. gracile, strain YL28 was identified as novel isolate of M. gracile despite its different physiological characteristics with respect to the species of M. gracile. The organism is possessed of slightly acid tolerance, higher amount of carotenoid of rhodopin and tolerance towards certain antibiotics, pesticide as well as heavy metals.

Topics: Bacteriochlorophyll A; Carotenoids; Chromatiaceae; DNA, Ribosomal; Molecular Sequence Data; Phylogeny; RNA, Ribosomal, 16S; Seawater

The light-harvesting complex 2 from the thermophilic purple bacterium Thermochromatium tepidum was purified and studied by steady-state absorption and fluorescence, sub-nanosecond-time-resolved fluorescence and femtosecond time-resolved transient absorption spectroscopy. The measurements were performed at room temperature and at 10 K. The combination of both ultrafast and steady-state optical spectroscopy methods at ambient and cryogenic temperatures allowed the detailed study of carotenoid (Car)-to-bacteriochlorophyll (BChl) as well BChl-to-BChl excitation energy transfer in the complex. The studies show that the dominant Cars rhodopin (N=11) and spirilloxanthin (N=13) do not play a significant role as supportive energy donors for BChl a. This is related with their photophysical properties regulated by long π-electron conjugation. On the other hand, such properties favor some of the Cars, particularly spirilloxanthin (N=13) to play the role of the direct quencher of the excited singlet state of BChl.

Topics: Bacteriochlorophylls; Carotenoids; Chromatiaceae; Cold Temperature; Energy Transfer; Kinetics; Light; Light-Harvesting Protein Complexes; Photosynthesis; Spectrometry, Fluorescence; Temperature; Time Factors; Xanthophylls

In this report, we present a study of carotenoid-bacteriochlorophyll energy transfer processes in two peripheral light-harvesting complexes (known as LH2) from purple bacteria. We use transient absorption spectroscopy with approximately 10 fs temporal resolution, which is necessary to observe the very fast energy relaxation processes. By comparing excited-state dynamics of the carotenoids in organic solvents and inside the LH2 complexes, it has been possible to directly evaluate their energy transfer efficiency to the bacteriochlorophylls. In the case of okenone in the LH2 complex from Chromatium purpuratum, we obtained an energy transfer efficiency of etaET2=63+/-2.5% from the optically active excited state (S2) and etaET1=61+/-2% from the optically dark state (S1); for rhodopin glucoside contained in the LH2 complex from Rhodopseudomonas acidophila these values become etaET2=49.5+/-3.5% and etaET1=5.1+/-1%. The measurements also enabled us to observe vibrational energy relaxation in the carotenoids' S1 state and real-time collective vibrational coherence initiated by the ultrashort pump pulses. Our results are important for understanding the dynamics of early events of photosynthesis and relating it to the structural arrangement of the chromophores.

Topics: Bacterial Chromatophores; Bacteriochlorophylls; Biophysics; Carotenoids; Chromatium; Energy Transfer; Fourier Analysis; Glucosides; Light; Light-Harvesting Protein Complexes; Models, Statistical; Oscillometry; Photochemistry; Proteobacteria; Rhodobacter sphaeroides; Rhodopseudomonas; Spectrophotometry; Time Factors