[Sphaerotilus dichotomus, a prospective biological agent for use in control of Culicidae].
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Culex↗
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Development and application of 16S rRNA-targeted probes for detection of iron- and manganese-oxidizing sheathed bacteria in environmental samples.
Comparative sequence analysis of the 16S rRNA genes from several Leptothrix and Sphaerotilus strains led to the design of an oligonucleotide probe (PS-1) based on a sequence within the hypervariable region 1 specific for four Leptothrix strains and for one of the four Sphaerotilus natans strains examined. Another probe (PSP-6) was based on a sequence within the hypervariable region 2. PSP-6 was specific for one of the two evolutionary lineages previously described for Leptothrix spp. (P. L. Siering and W. C. Ghiorse, Int. J. Syst. Bacteriol. 46:173-182, 1996). Fluorescein-labeled oligonucleotide probes were synthesized, and their specificity for fluorescence in situ hybridization identification was confirmed by a laser scanning microscopy technique (W. C. Ghiorse, D. N. Miller, R. L. Sandoli, and P. L. Siering, Microsc. Res. Tech. 33:73-86, 1996) to compare whole-cell hybridizations of closely related bacteria. Probe specificity was also tested in dot blot against total RNA isolated from four Leptothrix strains, four Sphaerotilus strains, and 15 other members of the class Proteobacteria. When the probes were tested on samples from the Sapsucker Woods wetland habitat where Leptothrix spp. are thought to play a role in manganese and iron oxidation, positive signals were obtained from several sheathed filamentous bacteria including some that were morphologically similar to previously isolated strains of "Leptothrix discophora." Other unknown filamentous sheathed bacteria also gave strong positive signals. This work provides a foundation for future studies correlating the presence of members of the Leptothrix-Sphaerotilus group of sheathed bacteria with manganese and iron oxidation activity in habitats where biological iron and manganese oxidation are important environmental processes.
Bacteria↗
Methylibium petroleiphilum gen. nov., sp. nov., a novel methyl tert-butyl ether-degrading methylotroph of the Betaproteobacteria.
A Gram-negative, rod-shaped, motile, non-pigmented, facultative aerobe that grew optimally at pH 6.5 and 30 degrees C (strain PM1T) was isolated for its ability to completely degrade the gasoline additive methyl tert-butyl ether. Analysis of the 16S rRNA gene sequence indicated that this bacterium was a member of the class Betaproteobacteria in the Sphaerotilus-Leptothrix group. The 16S rRNA gene sequence identity to other genera in this group, Leptothrix, Aquabacterium, Roseateles, Sphaerotilus, Ideonella and Rubrivivax, ranged from 93 to 96 %. The chemotaxonomic data including Q-8 as the major quinone, C16 : 1omega7c and C16 : 0 as the major fatty acids and a DNA G+C content of 69 mol%, support the inclusion of strain PM1T in the class Betaproteobacteria. It differed from other members of the Sphaerotilus-Leptothrix group by being a facultative methylotroph that used methanol as a sole carbon source, and by also being able to grow heterotrophically in defined media containing ethanol, toluene, benzene, ethylbenzene and dihydroxybenzoates as sole carbon sources. On the basis of the morphological, physiological, biochemical and genetic information, a new genus and species, Methylibium petroleiphilum gen. nov., sp. nov., is proposed, with PM1T (=ATCC BAA-1232T=LMG 22953T) as the type strain.
Base Composition↗
Light and electron microscopic studies of microorganisms growing in rotating biological contactor biofilms.
The biofilms growing in the first compartments of two rotating biological contactors used to treat municipal wastewater were examined by light and electron microscopy. The biofilms were found to contain a complex and varied microbial community that included filamentous and unicellular bacteria, protozoa, metazoa, and (possibly) bacteriophage. The predominant microorganism among these appeared to be a filamentous bacterium that was identical to Sphaerotilus in both morphological and ultrastructural characteristics. It was possible to isolate a Sphaerotilus-like bacterium from each contactor. Both the Sphaerotilus filaments and the wide variety of unicellular bacteria present tended to contain poly-beta-hydroxybutyrate inclusions, a probable indication that these organisms were removing carbon from the wastewater and storing it. The microbial population of the biofilms appeared to be metabolically active, as evidenced by the presence of microcolonies and dividing cells.
Journal Article↗
Isolation and characterization of an acidophilic, heterotrophic bacterium capable of oxidizing ferrous iron.
A heterotrophic bacterium, isolated from an acidic stream in a disused pyrite mine which contained copious growths of "acid streamers," displayed characteristics which differentiated it from previously described mesophilic acidophiles. The isolate was obligately acidophilic, with a pH range of 2.0 to 4.4 and an optimum pH of 3.0. The bacterium was unable to fix carbon dioxide but oxidized ferrous iron, although at a slower rate than either Thiobacillus ferrooxidans or Leptospirillum ferrooxidans. Elemental sulfur and manganese(II) were not oxidized. In liquid media, the isolate produced macroscopic streamerlike growths. Microscopic examination revealed that the bacterium formed long (greater than 100 microns) filaments which tended to disintegrate during later growth stages, producing single, motile cells and small filaments. The isolate did not appear to utilize the energy from ferrous iron oxidation. Both iron (ferrous or ferric) and an organic substrate were necessary to promote growth. The isolate displayed a lower tolerance to heavy metals than other iron-oxidizing acidophiles, and growth was inhibited by exposure to light. There was evidence of extracellular sheath production by the isolate. In this and some other respects, the isolate resembles members of the Sphaerotilus-Leptothrix group of filamentous bacteria. The guanine-plus-cytosine content of the isolate was 62 mol%, which is less than that recorded for Sphaerotilus-Leptothrix spp. and greater than those of L. ferrooxidans and most T. ferrooxidans isolates.
Bacteria↗
SPECTROCHEMICAL ANALYSIS OF INORGANIC ELEMENTS IN BACTERIA.
Rouf, M. A. (Washington State University, Pullman). Spectrochemical analysis of inorganic elements in bacteria. J. Bacteriol. 88:1545-1549. 1964.-Quantitative spectrochemical analyses of inorganic elements in the vegetative cells of Escherichia coli, Sphaerotilus natans, Micrococcus roseus, Bacillus cereus, and the spores of B. cereus were made. The following elements were found to be present in the ash samples: B, Na, Mg, Al, Si, P, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Sr, S, Ag, Sn, Ba, Pb, V, and Mo. These could be divided into major, minor, and trace elements, depending on the relative amounts in the cells. Mg, P, K, and S were considered as the major elements; Ca, Fe, Zn, and, perhaps, Cu and Mn as the minor elements, and the rest as trace elements. Mg concentrations were higher in the cells of the gram-positive M. roseus and B. cereus than in the gram-negative E. coli and S. natans. The latter organism contained 2.6% Fe(2)O(3) (dry weight basis). The vegetative cells of B. cereus were higher in Mg, P, K, Na, Ag, and lower in Si, Ca, Zn, Mn, and Cu than were its spores.
Bacillus cereus↗
Modelling of the acid-base properties of natural and synthetic adsorbent materials used for heavy metal removal from aqueous solutions.
In this paper a comparison about kinetic behaviour, acid-base properties and copper removal capacities was carried out between two different adsorbent materials used for heavy metal removal from aqueous solutions: an aminodiacetic chelating resin as commercial product (Lewatit TP207) and a lyophilised bacterial biomass of Sphaerotilus natans. The acid-base properties of a S. natans cell suspension were well described by simplified mechanistic models without electrostatic corrections considering two kinds of weakly acidic active sites. In particular the introduction of two-peak distribution function for the proton affinity constants allows a better representation of the experimental data reproducing the site heterogeneity. A priori knowledge about resin functional groups (aminodiacetic groups) is the base for preliminary simulations of titration curve assuming a Donnan gel structure for the resin phase considered as a concentrated aqueous solution of aminodiacetic acid (ADA). Departures from experimental and simulated data can be interpreted by considering the heterogeneity of the functional groups and the effect of ionic concentration in the resin phase. Two-site continuous model describes adequately the experimental data. Moreover the values of apparent protonation constants (as adjustable parameters found by non-linear regression) are very near to the apparent constants evaluated by a Donnan model assuming the intrinsic constants in resin phase equal to the equilibrium constants in aqueous solution of ADA and considering the amphoteric nature of active sites for the evaluation of counter-ion concentration in the resin phase. Copper removal outlined the strong affinity of the active groups of the resin for this ion in solution compared to the S. natans biomass according to the complexation constants between aminodiacetic and mono-carboxylic groups and copper ions.
Acid-Base Equilibrium↗
Characterization of biofilms occurred in seepage groundwater contaminated with petroleum within an urban subway tunnel.
Biofilms occurring in seepage groundwater contaminated with petroleum in an urban subway drainage system were characterized. The development of biofilms was observed only in the sites where petroleum-contaminated groundwater had seeped or was seeping. Moreover, the conditions of the biofilms such as color and development extent were influenced by the amount of spilled petroleum: By increasing the amount of spilled petroleum, the amount of biofilms increased and its color whitened. It deteriorated and became dark-brown if the contaminated groundwater did not seep any more. These facts indicate that the biofilms can be used as a preliminary indicator to identify the locations of fuel contaminated sumps and seeps without a more detailed assessment such as instrumental analysis. The biofilms were capable of degrading petroleum at 15 degrees C, which is similar to the average temperature of the seepage groundwater. Filamentous bacteria, Sphaerotilus spp., were isolated from the biofilms. It is considered that these bacteria are responsible for the development of biofilms in the seepage groundwater contaminated with petroleum because they can secrete extracellular polymeric substances.
Biodegradation, Environmental↗
Relationship of species-specific filament levels to filamentous bulking in activated sludge.
To examine the relationship between activated-sludge bulking and levels of specific filamentous bacteria, we developed a statistics-based quantification method for estimating the biomass levels of specific filaments using 16S rRNA-targeted fluorescent in situ hybridization (FISH) probes. The results of quantitative FISH for the filament Sphaerotilus natans were similar to the results of quantitative membrane hybridization in a sample from a full-scale wastewater treatment plant. Laboratory-scale reactors were operated under different flow conditions to develop bulking and nonbulking sludge and were bioaugmented with S. natans cells to stimulate bulking. Instead of S. natans, the filament Eikelboom type 1851 became dominant in the reactors. Levels of type 1851 filaments extending out of the flocs correlated strongly with the sludge volume index, and extended filament lengths of approximately 6 x 10(8) micro m ml(-1) resulted in bulking in laboratory-scale and full-scale activated-sludge samples. Quantitative FISH showed that high levels of filaments occurred inside the flocs in nonbulking sludge, supporting the "substrate diffusion limitation" hypothesis for bulking. The approach will allow the monitoring of incremental improvements in bulking control methods and the delineation of the operational conditions that lead to bulking due to specific filaments.
Biomass↗
Novel approach to quantitative detection of specific rRNA in a microbial community, using catalytic DNA.
We developed a novel method for the quantitative detection of the 16S rRNA of a specific bacterial species in the microbial community by using deoxyribozyme (DNAzyme), which possesses the catalytic function to cleave RNA in a sequence-specific manner. A mixture of heterogeneous 16S rRNA containing the target 16S rRNA was incubated with a species-specific DNAzyme. The cleaved target 16S rRNA was separated from the intact 16S rRNA by electrophoresis, and then their amounts were compared for the quantitative detection of target 16S rRNA. This method was used to determine the abundance of the 16S rRNA of a filamentous bacterium, Sphaerotilus natans, in activated sludge, which is a microbial mixture used in wastewater treatment systems. The result indicated that this DNAzyme-based approach would be applicable to actual microbial communities.
Base Sequence↗
Effects of fatty acids on growth and poly-3-hydroxybutyrate production in bacteria.
The effects of saturated and unsaturated fatty acids (lauric acid, palmitic acid, steric acid, oleic acid, linoleic acid, soybean oil) on Sphaerotilus natans, 0B17 (Pseudomonas sp.), and recombinant Escherichia coli DH5(/pUC19/CAB were studied. Oleic acid enhances Poly-3-hydroxybutyrate (PHB) production in these three bacterial strains, suggesting that the single double bond of the acid activates the polyhydroxylkanoate accumulation enzymatic reaction. Under the effect of lauric acid and linoleic acid, the growth of S. natans and 0B17 were totally inhibited. However, the enhanced PHB accumulation in recombinant E. coli was observed.
Bioreactors↗
Characterization of Bacterial Communities from Activated Sludge: Culture-Dependent Numerical Identification Versus In Situ Identification Using Group- and Genus-Specific rRNA-Targeted Oligonucleotide Probes
The structures of bacterial communities were studied in activated sludge samples obtained from the aerobic and anaerobic zones of a wastewater treatment plant showing enhanced phosphorous removal. Samples were analyzed by in situ hybridization with oligonucleotide probes complementary to selected regions of the 16S and 23S ribosomal RNA (rRNA) characteristic for defined phylogenetic entities (genera and larger groups). The microbial community structures revealed by molecular techniques were compared with the compositions of culturable bacterial communities, obtained from the characterization of 255 isolates from tryptone-soy (TS) agar and R2A agar. These isolates were characterized by 89 physiological tests and their cellular fatty acid patterns, and identified. Culture-dependent techniques indicated the following distribution: different Aeromonas spp. (2.7-8.3% on R2A agar; 45.0-63.7% on TS agar), Acinetobacter spp. (5.4-9.0% on R2A agar; 5.0-9.1% on TS agar), Pseudomonas spp. (up to 10% on R2A agar) and Shewanella putrefaciens (up to 3.0% on R2A agar), all members of the gamma subclass of Proteobacteria, were isolated most frequently. The relatively rare isolates of the beta subclass were identified as Acidovorax spp., Alcaligenes spp., and Comamonas spp.. The Gram-positive bacteria (high DNA G+C) were assigned mainly to Arthrobacter spp., Microbacterium spp., and Mycobacterium phlei. In order to assess the in situ abundance of the most frequently isolated genus, Aeromonas, two rRNA-targeted oligonucleotide probes were developed. The two gamma proteobacterial genera Aeromonas and Acinetobacter constituted less than 5% of all bacteria. In situ, Proteobacteria belonging to the beta subclass and high G+C Gram-positive bacteria were dominant. From filamentous bacteria, Sphaerotilus spp. and Leptothrix spp. could be detected occasionally. In addition, one sample contained a high proportion of the morphologically distinct filaments of Microthrix parvicella.
Journal Article↗
[Biosynthesis of phenylalanine and tyrosine: arogenic acid, a new intermediate product].
With the discovery of arogenic acid two new pathways for the biosynthesis of phenylalanine and tyrosine have been revealed. The occurrence of two, three, or four pathways for the biosynthesis of phenylalanine and tyrosine in microorganisms and plants may be a useful tool for taxonomic classifications. Investigations on enterobacteriaceae, pseudomonads, flavobacteria, streptomycetes, archaebacteria, and on Sphaerotilus, Trichococcus and Leptothrix species from bulking sludge are described. The possible role of arogenate in the evolution of the pathways for tyrosine and phenylalanine biosynthesis is discussed.
Amino Acids, Dicarboxylic↗
Structural and physiological characteristics of some sheathed bacteria.
The fine structure and growth of two gram-negative and two gram-positive strains of sheathed bacteria, isolated from activated sludge, have been studied. Their anatomy is quite different from Sphaerotilus natans. The cells are rectangular, tightly joined together, non-motile and enclosed by a sheath which is thin in the gram-negative strains and rather electron-dense in the two larger gram positive strains. The four strains grow slowly and form pink filamentous flocs in liquid media.
Bacteria↗
Filamentous bacteria-induced sludge bulking can alter antibiotic resistance gene profiles and increase potential risks in wastewater treatment systems.
Sludge bulking caused by filamentous bacteria is a prevalent issue in wastewater treatment systems. While previous studies have primarily concentrated on controlling sludge bulking, the biological risks associated with it have been overlooked. This study demonstrates that excessive growth of filamentous bacteria during sludge bulking can significantly increase the abundance of antibiotic resistance genes (ARGs) in activated sludge. Through metagenomic analysis, we identified specific ARGs carried by filamentous bacteria, such as Sphaerotilus and Thiothrix, which are responsible for bulking. Additionally, by examining over 1,000 filamentous bacterial genomes, we discovered a diverse array of ARGs across different filamentous bacteria derived from wastewater treatment systems. Our findings indicate that 74.84% of the filamentous bacteria harbor at least one ARG, with the occurrence frequency of ARGs in these bacteria being approximately 1.5 times higher than that in the overall bacterial population in activated sludge. Furthermore, genomic and metagenomic analyses have shown that the ARGs in filamentous bacteria are closely linked to mobile genetic elements and are frequently found in potentially pathogenic bacteria, highlighting potential risks posed by these filamentous bacteria. These insights enhance our understanding of ARGs in activated sludge and underscore the importance of risk management in wastewater treatment systems.
Sewage↗
Effect of chlorine on filamentous microorganisms present in activated sludge as evaluated by respirometry and INT-dehydrogenase activity.
Activated sludge technology is more used than any other for biological treatment of wastewater. However, filamentous bulking is a very common problem in activated sludge plants, chlorine being the chemical agent normally used to control it. In this work the effect of chlorine on microorganisms present in activated sludge flocs was assessed by a respirometric technique (oxygen uptake rate, OUR) and by the INT-dehydrogenase activity test (DHA) measured by two techniques: spectrophotometry (DHA(a)) and image analysis (DHA(i)). Both DHA tests were optimized and correlated with the respirometric technique (OUR) using pure cultures of a filamentous microorganism (Sphaerotilus natans) under chlorine inhibition. Using these correlations the tested methods were applied to determine the action of chlorine on respiratory activity in activated sludge. The OUR and the DHA(a) quantifies the action of chlorine on the total respiratory activity (RA) of flocs (filamentous and floc-forming bacteria); in contrast, the DHA(i) test evaluates specific action of chlorine on the RA of filamentous microorganisms. In activated sludge flocs containing filamentous microorganisms, a chlorine dose of 4.75 mgCl(2) (gVSS)(-1) with a contact time of 20 min reduced about 80% of the RA of filamentous bacteria while affecting only 50-60% of the total RA of flocs. Besides, a chlorine dose of 7.9 mgCl(2) (gVSS)(-1) produced the total respiratory inactivation of filamentous microorganisms after 10 min contact, however, with this dose the total RA of activated sludge flocs was reduced only about 45-65%; controlling filamentous bulking without affecting too much floc-forming bacteria. At the tested chlorine concentrations the inhibition of filamentous microorganisms was higher than in the whole activated sludge. Although floc-forming microorganisms were demonstrated to be more susceptible to chlorine than filamentous in pure cultures, results obtained in the present work confirmed that it is the location of the filamentous microorganisms in the flocs and the presence of extracellular polymer substances which largely determines their higher susceptibility to chlorine; consequently this feature plays a critical role in bulking control.
Bacteria↗
Multi-metallic modelling for biosorption of binary systems.
In this paper a specially propagated biomass of Sphaerotilus natans was tested as adsorbent for binary solutions of Cu-Cd, Cu-Pb and Cu--Zn at different equilibrium pH. The experimental results outline the buffering effect of H+ at low pH. which masks the competition among metals. In each binary system the biomass affinity follows the acidic properties of the heavy metals probably due to an ionic exchange mechanism operating among active sites and metals in solution. The experimental results were fitted according to an empirical approach with growing complexity that outlines the inadequacy of the predictive models and the non-ideal interactions among metals.
Adsorption↗
Impact of the repetition of oxygen deficiencies on the filamentous bacteria proliferation in activated sludge.
Cases of low stress can frequently occur in a wastewater treatment plant (WWTP). As they have no visible impact on the plant operation, they generally go unnoticed. Nevertheless, it would appear that an accumulation of such cases can result in serious operational problems. The impact of the repeated application of oxygen deficiency on the proliferation of the filamentous bacteria Sphaerotilus natans, Haliscomenobacter hydrossis, Eikelboom type 021N and Thiothrix spp has been studied on WWTP pilots. Two different oxygen deficiencies series were tested. Filamentous bacteria evolution in activated sludge was monitored using fluorescent in situ hybridization. For the weak deficiencies, no significant variation in the filamentous bacteria response level was recorded, whereas with more severe deficiencies the filamentous bacteria response increased considerably with the increase in stress number. From the results obtained, it would appear that there is an intensity and frequency threshold beyond which the filamentous bacteria response levels increase when the stress is applied in series. This "oxygen deficiencies repetition" appears to be an important factor in the appearance of bulking.
Bacteria↗