RESUMEN
LbL nano self-assembly coating of A. vinosum with different polyelectrolyte combinations is presented as an example to investigate substrate uptake in bacteria. The effects of surface charge and the formation of a physical barrier provides new insights in the contact mechanisms between the cell surface and insoluble elemental sulfur. Furthermore, uptake of sulfide by encapsulated cells was investigated. Growth experiments of coated cells showed that surface charge did neither affect sulfide uptake nor the contact formation between the cells and solid sulfur. However, increasing layers slowed or inhibited the uptake of sulfide and elemental sulfur. This work demonstrates how defining surface properties of bacteria has potential for microbiological and biotechnological applications.
Asunto(s)
Membrana Celular/metabolismo , Chromatiaceae/citología , Chromatiaceae/metabolismo , Nanotecnología/métodos , Proteínas Bacterianas/metabolismo , Chromatiaceae/crecimiento & desarrollo , Técnicas Electroquímicas , Espacio Intracelular/metabolismo , Microscopía Confocal , Nanocáscaras/microbiología , Sulfatos/metabolismo , Azufre/metabolismo , Propiedades de SuperficieRESUMEN
Quantitative information on the ecophysiology of individual microorganisms is generally limited because it is difficult to assign specific metabolic activities to identified single cells. Here, we develop and apply a method, Halogen In Situ Hybridization-Secondary Ion Mass Spectroscopy (HISH-SIMS), and show that it allows simultaneous phylogenetic identification and quantitation of metabolic activities of single microbial cells in the environment. Using HISH-SIMS, individual cells of the anaerobic, phototropic bacteria Chromatium okenii, Lamprocystis purpurea, and Chlorobium clathratiforme inhabiting the oligotrophic, meromictic Lake Cadagno were analyzed with respect to H(13)CO(3)(-) and (15)NH(4)(+) assimilation. Metabolic rates were found to vary greatly between individual cells of the same species, showing that microbial populations in the environment are heterogeneous, being comprised of physiologically distinct individuals. Furthermore, C. okenii, the least abundant species representing approximately 0.3% of the total cell number, contributed more than 40% of the total uptake of ammonium and 70% of the total uptake of carbon in the system, thereby emphasizing that numerically inconspicuous microbes can play a significant role in the nitrogen and carbon cycles in the environment. By introducing this quantification method for the ecophysiological roles of individual cells, our study opens a variety of possibilities of research in environmental microbiology, especially by increasing the ability to examine the ecophysiological roles of individual cells, including those of less abundant and less active microbes, and by the capacity to track not only nitrogen and carbon but also phosphorus, sulfur, and other biological element flows within microbial communities.
Asunto(s)
Bacterias Anaerobias/citología , Bacterias Anaerobias/fisiología , Ecosistema , Procesos Fototróficos , Biomasa , Carbono/metabolismo , Chlorobi/citología , Chromatiaceae/citología , Agua Dulce , Microscopía Fluorescente , Nitrógeno/metabolismo , Oxígeno/metabolismo , Compuestos de Amonio Cuaternario/metabolismo , Suiza , Factores de TiempoRESUMEN
OBJECTIVE: To exploit resources of purple sulfur bacteria and their photosynthetic genes. METHODS: A purple sulfur bacterium strain 283-1 of okenone-containing, halophilic, high sulfide tolerance was isolated by agar dilution method in Pfennig medium from photolithoautotrophic enrichments of Dongfeng saltern, Qingdao, China. RESULTS: Cells of strain 283-1 were Gram-negative, halophile, straight or slightly curved rods, motile by monopolar single flagella, no gas vacuoles, carotenoid of okenone series and bacteriochlorophylla as photosynthetic pigment, purple red. It could photolithoautotrophically grow under anoxic condition in the light with sulfide as electron donor, sulfur globules accumulate as intermediate oxidation product and stored in the form of highly refractile globules inside the cells. The strain 283-1 belonged to Gammaproteobacteria, Chromatiales, Chroamtiaceae, genus of Marichromatium. Phylogenetic analysis based on 16S rRNA gene sequence also confirmed that strain 283-1 belonged to Marichromatium genus. However, the physiological characteristics of strain 283-1 were significantly different from four species of the genus Marichromatium. NaCl requirement range from 1% to 15%, good growth was observed at 7.5 mmol x L-(-1) NaS x 9H2O, 45 degrees C, 5000 lux and pH 9.0, a number of organic substances of C3 and C4 of TCA cycles and gluconate could be photoassililated in the presence of sulfide, no growth factors were required. CONCLUSION: On the basis of 16S rRNA gene sequence analysis and its morphological and physiological characteristics, strain 283-1 is a new isolate of Marichromatium genus, named as Marichromatium sp. 283-1.
Asunto(s)
Carotenoides/metabolismo , Chromatiaceae/aislamiento & purificación , Chromatiaceae/fisiología , Filogenia , Tolerancia a la Sal , Absorción , Proliferación Celular/efectos de los fármacos , Proliferación Celular/efectos de la radiación , Chromatiaceae/citología , Chromatiaceae/metabolismo , ADN Ribosómico/genética , Concentración de Iones de Hidrógeno , Luz , Fotólisis , Cloruro de Sodio/farmacología , TemperaturaRESUMEN
A Gram-negative, rod-shaped, motile, non-spore-forming bacterium, designated strain A62-14B(T), was isolated from a constant-temperature, spring-fed, freshwater lake. On the basis of the complete 16S rRNA gene sequence, strain A62-14B(T) was shown to belong to the class Gammaproteobacteria, being most closely related to Rheinheimera sp. HTB082 (96.2 % sequence similarity), Rheinheimera baltica (95.01 %), Rheinheimera pacifica (96.35 %), Rheinheimera perlucida and Alishewanella fetalis (95.9 %). The major fatty acids (C(16 : 1)omega7c, 38.56 %; C(16 : 0), 19.04 %; C(12 : 0) 3-OH, 12.83 %; C(18 : 1)omega7c, 7.70 %) and the motility of strain A62-14B(T) support its affiliation to the genus Rheinheimera. The salt intolerance of strain A62-14B(T), together with the results of other physiological and biochemical tests, allowed the differentiation of this strain from the three species of the genus Rheinheimera with validly published names. Therefore strain A62-14B(T) represents a novel species of the genus Rheinheimera, for which the name Rheinheimera texasensis sp. nov. is proposed. The type strain is A62-14B(T) (=ATCC BAA-1235(T)=DSM 17496(T)). The description of the genus Rheinheimera is emended to reflect the halointolerance and freshwater origin of strain A62-14B(T).
Asunto(s)
Chromatiaceae/clasificación , Chromatiaceae/aislamiento & purificación , Agua Dulce/microbiología , Antibacterianos/farmacología , Técnicas de Tipificación Bacteriana , Chromatiaceae/citología , Chromatiaceae/fisiología , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Ácidos Grasos/análisis , Genes de ARNr , Locomoción/fisiología , Datos de Secuencia Molecular , Filogenia , ARN Bacteriano/genética , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Homología de Secuencia de Ácido Nucleico , Cloruro de Sodio/farmacología , Esporas Bacterianas/citologíaRESUMEN
We show the potential of flow cytometry as a fast tool for population identification and enumeration of photosynthetic sulfur bacteria. Purple (PSB) and green sulfur bacteria (GSB) oxidize hydrogen sulfide to elemental sulfur that can act as storage compound to be further oxidized to sulfate generating the reducing power required for growth. Both groups have different elemental sulfur allocation strategies: whereas PSB store elemental sulfur as intracellular inclusions, GSB allocate sulfur globules externally. We used well-characterized laboratory strains and complex natural photosynthetic populations developing in a sharply stratified meromictic lake to show that PSB and GSB could be detected, differentiated and enumerated in unstained samples using a blue laser-based flow cytometer. Variations in cell-specific pigment content and the dynamics of sulfur accumulation, both intra- and extracellularly, were also detected in flow cytometric plots as sulfur accumulation changed the light scatter characteristics of the cells. These data were used to show the potential for studies on the metabolic status and the rate of activity at the single-cell level. Flow cytometric identification and enumeration resulted in faster and more precise analyses than previous approaches, and may open the door to more complex ecophysiological experiments with photosynthetic sulfur bacteria in mixed cultures and natural environments.
Asunto(s)
Chlorobi/citología , Chromatiaceae/citología , Recuento de Colonia Microbiana/métodos , Citometría de Flujo/métodos , Agua Dulce/microbiología , Azufre/metabolismo , Chlorobi/aislamiento & purificación , Chlorobi/metabolismo , Chromatiaceae/aislamiento & purificación , Chromatiaceae/metabolismo , Cinética , España , Sulfuros/metabolismoRESUMEN
A rod-shaped, phototrophic, purple sulfur bacterium, strain JA124(T), was isolated in pure culture from a marine aquaculture pond, located near Bhimunipatnam, in a medium that contained 3 % NaCl (w/v). Strain JA124(T) is a Gram-negative, motile rod with a single polar flagellum. Strain JA124(T) has a requirement for NaCl, with optimum growth at 1.5-8.5 %, and tolerates up to 11 % NaCl. Intracellular photosynthetic membranes are of the vesicular type. Bacteriochlorophyll a and probably carotenoids of the spirilloxanthin series are present as photosynthetic pigments. Strain JA124(T) was able to utilize sulfide, sulfate, thiosulfate, sulfite, thioglycollate and cysteine as sulfur sources. Strain JA124(T) was able to grow photolithoautotrophically, photolithoheterotrophically and photo-organoheterotrophically. Chemotrophic and fermentative growth could not be demonstrated. Strain JA124(T) lacks diazotrophic growth and acetylene reduction activity. Pyridoxal phosphate is required for growth. During growth on reduced sulfur sources as electron donors, sulfur is deposited intermediately as a number of small granules within the cell. Phylogenetic analysis on the basis of 16S rRNA gene sequences showed that strain JA124(T) clusters with species of the genus Marichromatium belonging to the class Gammaproteobacteria. The highest sequence similarities of strain JA124(T) were found with the type strains of Marichromatium indicum (98 %), Marichromatium purpuratum (95 %) and Marichromatium gracile (93 %). However, DNA-DNA hybridization with Marichromatium indicum DSM 15907(T) revealed relatedness of only 65 % with strain JA124(T). The DNA base composition of strain JA124(T) was 67 mol% G+C (by HPLC). Based on 16S rRNA gene sequence analysis, morphological and physiological characteristics and DNA-DNA hybridization studies, strain JA124(T) (=ATCC BAA-1316(T)=JCM 13911(T)) is sufficiently different from other Marichromatium species to merit its description as the type strain of a novel species, Marichromatium bheemlicum sp. nov.
Asunto(s)
Acuicultura , Chromatiaceae/clasificación , Chromatiaceae/aislamiento & purificación , Agua de Mar/microbiología , Acetileno/metabolismo , Proteínas Bacterianas/análisis , Técnicas de Tipificación Bacteriana , Bacterioclorofilas/análisis , Composición de Base , Chromatiaceae/citología , Chromatiaceae/fisiología , Vesículas Citoplasmáticas/fisiología , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Electroforesis en Gel de Poliacrilamida , Flagelos/fisiología , Genes de ARNr , India , Locomoción , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Fotosíntesis , Filogenia , Proteoma/análisis , ARN Bacteriano/genética , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Homología de Secuencia de Ácido Nucleico , Azufre/metabolismo , Xantófilas/análisisRESUMEN
We report a previously unknown process in which anoxygenic phototrophic bacteria use nitrite as an electron donor for photosynthesis. We isolated a purple sulfur bacterium 98% identical to Thiocapsa species that stoichiometrically oxidizes nitrite to nitrate in the light. Growth and nitrate production strictly depended on both light and nitrite. This is the first known microbial mechanism for the stoichiometric oxidation of nitrite to nitrate in the absence of oxygen and the only known photosynthetic oxidation in the nitrogen cycle. This work demonstrates nitrite as the highest-potential electron donor for anoxygenic photosynthesis known so far.
Asunto(s)
Chromatiaceae/metabolismo , Nitritos/metabolismo , Fotosíntesis , Chromatiaceae/citología , Chromatiaceae/crecimiento & desarrollo , Chromatiaceae/aislamiento & purificación , Transporte de Electrón , Sedimentos Geológicos/microbiología , Luz , Nitratos/metabolismo , Oxidación-Reducción , Aguas del Alcantarillado/microbiologíaRESUMEN
A new purple sulfur bacterium (strain M9) was isolated from the steppe soda Lake Dzun Uldziin Nur (pH 9.4; mineralization, 3.3%) situated in southeastern Mongolia. Individual cells appear as vibrios 0.3-0.5 x 0.7-1 micron in size. The dividing cells often do not separate from each other, forming an almost closed ring. The internal photosynthetic membranes are represented by concentric lamellae lining the cell wall. Photosynthetic pigments are bacteriochlorophyll a and carotenoids of the spirilloxanthin series. The main carotenoid (> 96%) is spirilloxanthin. Two typical light-harvesting complexes (LH1 and LH2) are present in the membranes in a 1:1 ratio. The bacterium is an anaerobe and facultative photoorganoheterotroph. Photolithoautotrophic growth on sulfide is scarce. Thiosulfate is utilized as an electron donor only in the presence of organic matter. Globules of elemental sulfur are formed as an intermediary product of sulfide and thiosulfate oxidation and are deposited outside the cells. The end product of oxidation is sulfate. In the presence of sulfide and carbonates, acetate, lactate, malate, pyruvate, propionate, succinate, and fumarate are used as the additional sources of carbon in anoxygenic photosynthesis. Vitamin are not required. The bacterium is an alkaliphile the pH optimum is at 8.3-9.1, the pH range is 7.6-10.1. The optimum NaCl concentration in the medium is 1 to 7%; the range is 0.5 to 0.9%. The optimum carbonate content in the medium is 2%; the range is 1 to 10%. The best growth occurs at 30-35 degrees C. The DNA G + C content is 57.5 mol%. According to the results of analysis of the 16S rRNA gene sequences, the new isolate M9 belongs to the phylogenetic cluster containing representatives of the family Ectothiorhodospiraceae within the class "Gammaproteobacteria." In this class, the new isolate forms a new branch, which occupies an intermediate position between the representatives of the genera Ectothiorhodospira and Thiorhodospira. Based on the phenotypic and genetic characteristics, the new purple sulfurbacterium was assigned to a new species of a new genus of the family Ectothiorhodospiraceae, Ectothiorhodosinus mongolicum gen. nov., sp. nov.
Asunto(s)
Chromatiaceae/fisiología , Microbiología del Agua , Anaerobiosis , Carotenoides , Clorofila , Clorofila A , Chromatiaceae/clasificación , Chromatiaceae/citología , Medios de Cultivo , Concentración de Iones de Hidrógeno , Mongolia , Oxidación-Reducción , Fotosíntesis , Pigmentos Biológicos , Sulfuros/química , Sulfuros/metabolismo , Tiosulfatos/química , Tiosulfatos/metabolismoRESUMEN
Strain ALEN 2(T) was isolated from a mixed culture capable of complete autotrophic denitrification with thiosulfate as electron donor at pH 10; the mixed culture was enriched from sediment from Lake Fazda (Wadi Natrun, Egypt), a hypersaline alkaline lake. The isolate had large, non-motile, coccoid or barrel-shaped cells with intracellular sulfur globules. The bacterium was obligately chemolithoautotrophic. It grew with reduced sulfur compounds aerobically and anaerobically with nitrate as electron acceptor, nitrate being reduced to nitrite. It was moderately halophilic and obligately alkaliphilic. On the basis of genetic analysis and its unique phenotype, strain ALEN 2(T) (=DSM 14787(T)=UNIQEM 213(T)) is proposed as the type strain of a novel species of the genus Thialkalivibrio, Thialkalivibrio nitratireducens.
Asunto(s)
Chromatiaceae/clasificación , Nitratos/metabolismo , Filogenia , Microbiología del Agua , Chromatiaceae/citología , Chromatiaceae/aislamiento & purificación , Chromatiaceae/metabolismo , Egipto , Sedimentos Geológicos/microbiología , Concentración de Iones de Hidrógeno , Datos de Secuencia Molecular , Oxidación-Reducción , Consumo de Oxígeno , Sulfatos/metabolismo , Azufre/metabolismoRESUMEN
The motility of the purple sulfur bacterium Marichromatium gracile was investigated under different light regimes in a gradient capillary setup with opposing oxygen and sulfide gradients. The gradients were quantified with microsensors, while the behavior of swimming cells was studied by video microscopy in combination with a computerized cell tracking system. M. gracile exhibited photokinesis, photophobic responses, and phobic responses toward oxygen and sulfide. The observed migration patterns could be explained solely by the various phobic responses. In the dark, M. gracile formed an approximately 500-microm-thick band at the oxic-anoxic interface, with a sharp border toward the oxic zone always positioned at approximately 10 microM O(2). Flux calculations yielded a molar conversion ratio S(tot)/O(2) of 2.03:1 (S(tot) = [H(2)S] + [HS(-)] + [S(2-)]) for the sulfide oxidation within the band, indicating that in darkness the bacteria oxidized sulfide incompletely to sulfur stored in intracellular sulfur globules. In the light, M. gracile spread into the anoxic zone while still avoiding regions with >10 microM O(2). The cells also preferred low sulfide concentrations if the oxygen was replaced by nitrogen. A light-dark transition experiment demonstrated a dynamic interaction between the chemical gradients and the cell's metabolism. In darkness and anoxia, M. gracile lost its motility after ca. 1 h. In contrast, at oxygen concentrations of >100 microM with no sulfide present the cells remained viable and motile for ca. 3 days both in light and darkness. Oxygen was respired also in the light, but respiration rates were lower than in the dark. Observed aggregation patterns are interpreted as effective protection strategies against high oxygen concentrations and might represent first stages of biofilm formation.
Asunto(s)
Chromatiaceae/fisiología , Luz , Oxígeno/farmacología , Sulfuros/farmacología , Chromatiaceae/citología , Chromatiaceae/efectos de los fármacos , Oscuridad , Microscopía por Video , Movimiento/efectos de los fármacos , Movimiento/fisiología , Oxidación-ReducciónRESUMEN
Sequences of the 16S rDNA from all available type strains of Chromatium species have been determined and were compared to those of other Chromatiaceae, a few selected Ectothiorhodospiraceae and Escherichia coli. The clear separation of Ectothiorhodospiraceae and Chromatiaceae is confirmed. Most significantly the sequence comparison revealed a genetic divergence between Chromatium species originated from freshwater sources and those of truly marine and halophilic nature. Major phylogenetic branches of the Chromatiaceae contain (i) marine and halophilic species, (ii) freshwater Chromatium species together with Thiocystis species and (iii) species of the genera Thiocapsa and Amoebobacter as recently reclassified [Guyoneaud, R. & 6 other authors (1988). Int J Syst Bacteriol 48, 957-964], namely Thiocapsa roseopersicina, Thiocapsa pendens (formerly Amoebobacter pendens), Thiocapsa rosea (formerly Amoebobacter roseus), Amoebobacter purpureus and Thiolamprovum pedioforme (formerly Amoebobacter pedioformis). The genetic relationships between the species and groups are not in congruence with the current classification of the Chromatiaceae and a reclassification is proposed on the basis of 16S rDNA sequence similarity supported by selected phenotypic properties. The proposed changes include the transfers of Chromatium minus and Chromatium violascens to Thiocystis minor comb. nov. and Thiocystis violascens comb. nov., of Chromatium vinosum, Chromatium minutissimum and Chromatium warmingii to the new genus Allochromatium as Allochromatium vinosum comb. nov., Allochromatium minutissimum comb. nov., and Allochromatium warmingii comb. nov., of Chromatium tepidum to the new genus Thermochromatium as Thermochromatium tepidum comb. nov., of Chromatium salexigens and Chromatium glycolicum to the new genus Halochromatium as Halochromatium salexigens comb. nov. and Halochromatium glycolicum comb. nov., of Chromatium gracile and Chromatium purpuratum to the new genus as Marichromatium gracile comb. nov. and Marichromatium purpuratum comb. nov., of Thiocapsa pfennigii to Thiococcus pfennigii gen. nom. rev., of Thiocapsa halophila to the new genus Thiohalocapsa as Thiohalocapsa halophila comb. nov., and of Chromatium buderi to the new genus Isochromatium as Isochromatium buderi comb. nov.
Asunto(s)
Chromatiaceae/clasificación , Filogenia , Chromatiaceae/citología , Chromatiaceae/genética , Chromatiaceae/fisiología , Chromatium/clasificación , ADN Bacteriano/química , ADN Ribosómico/química , Agua Dulce , Biología Marina , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , ARN Ribosómico 18S/genética , Análisis de Secuencia de ADN , Especificidad de la Especie , Terminología como Asunto , Microbiología del AguaAsunto(s)
Chromatiaceae , Rhodospirillaceae , Rhodospirillales , Proteínas Bacterianas/análisis , Bacterioclorofilas/análisis , Chromatiaceae/clasificación , Chromatiaceae/citología , Chromatiaceae/fisiología , Cianobacterias , ADN Bacteriano/análisis , Movimiento , Fotosíntesis , Pigmentos Biológicos , Rhodospirillaceae/clasificación , Rhodospirillaceae/citología , Rhodospirillaceae/fisiología , Rhodospirillales/clasificación , Rhodospirillales/citología , Rhodospirillales/fisiología , Proteínas Ribosómicas/análisis , Azufre/metabolismoRESUMEN
The structure of bacterial communities, the distribution of sulfide and oxygen, bacteriochlorophyll concentrations, and the temperature profile were determined for the anaerobic hypolimnia of two lakes in southern Michigan. Information from these studies, plus qualitative observations of two other lakes and two ponds over a 4-year period were used to correlate the spatial distribution of the populations, cell size, arrangement of photosynthetic vesicles or lamellae, presence of gas vacuoles or flagella, sulfur deposition, and environmental factors. On the basis of these results, three communities designated as A, B, and C were defined. The upper (A) community consisted of sequentially layered purple sulfur bacteria including two or more of the following genera: Thiopedia, Thiospirillum, Thiocystis, or Chromatium. The middle (B) community consisted of sequential layers of green bacteria from one or more of the following genera: Pelodictyon, Clathrochloris, Chlorochromatium, or Prosthecochloris. The lowest (C)community contained previously unreported gas-vacuolate colorless bacteria 0 to 0.7 m above the sediment. Microstratification (0.1- to 0.2-m layers) of populations was observed within the A and B communities.