Hyphomicrobia and the oxidation of manganesse in aquatic ecosystems

Biogenic manganese deposits from freshwater pipelines in many parts of the world have been examined chemically and microbiologically. For chemical analysis to indicate the nature of the deposit the sampling procedure must ensure that the biogenic deposit is not contaminated by abiogenic material. Hyphomicrobium is abundant in manganese deposits from world-wide location but it is not the only manganese-oxidizing bacterium. The difficulties of assessing the relative importance of hyphomicrobia and other manganese bacteria, and of formulating satisfactory culture media, are discussed.Examination of accredited deposits and laboratory cultures suggests that some hyphomicrobia preferentially oxidize manganese rather than iron.I gratefully acknowledge all those persons and institutions who supplied samples of manganese deposits, and in particular The Hydro-Electric Commission, Tasmania; The Snowy Mountains Authority; Northern Electricity Authority of Queensland; Miss I. J. Powling, State Rivers and Water Supply Commission, Victoria; Melbourne and Metropolitan Board of Works; Mr. G. E. Hollis, New Zealand Electricity Department; Mr. J. Henderson, North-West Gloucestershire Water Boards, and Mrs. K. Ormerod, Norsk Institut for Vannforskning. I thank Mrs. P. M. Scarborough, Mr. R. Buckney for technical assistance, and the Australian Research Grants Committee for a grant.     

Pleomorphy in Stalked, Budding Bacteria

An investigation of hyphomicrobia from manganese deposits and various fresh-water habitats revealed an astonishing degree of pleomorphy in the group. A range of variation spanning two described genera (Hyphomicrobium and Pedomicrobium) was induced by varying culture conditions and was further observed in natural environments. It is suggested that Pedomicrobium is an invalid genus.     

Form and function in manganese-oxidizing bacteria

Summary Stalked, budding bacteria of the genus Hyphomicrobium are shown to be responsible for manganese deposition in freshwater pipelines. The attachment of the cells to the pipe surface is considered from the point of view of electrostatic attraction and the production of holdfast material. Electrophoretic studies indicate that Hyphomicrobium cells are negatively charged and that their surface ionogenic groups are carboxylic. It is postulated that the curious morphology and mode of reproduction of hyphomicrobia accounts for their efficiency in producing, or coexisting with, the manganese oxides they produce.

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Zusammenfassung Die gestielte Bakteriengattung der Hyphomikroben wird für die Manganschlammablagerungen in Süßwasserdruckrohrleitungen verantwortlich gemacht. Die Bindung der Zellen an die Rohroberfläche soll durch elektrostatische Anziehungskraft und Bildung von Haftmaterial bewirkt werden. Die elektrophoretischen Versuche zeigen, daß die Hyphomicrobium-Zellen negativ geladen und die Ionen-Gruppen der Oberfläche Carboxyle sind. Es wird postuliert, daß die eigentümliche Morphologie und Vermehrungsweise der Hyphomikroben verantwortlich sind für ihre Fähigkeit, Manganoxyde zu bilden und mit ihnen gemeinsam zu existieren.

     

Geomicrobiology of Cave Ferromanganese Deposits: A Field and Laboratory Investigation

Abstract

Unusual ferromanganese deposits are found in several caves in New Mexico. The deposits are enriched in iron and manganese by as much as three orders of magnitude over the bedrock, differing significantly in mineralogy and chemistry from bedrock-derived insoluble residue. The deposits contain metabolically active microbial communities. Enrichment cultures inoculated from the ferromanganese deposits produced manganese oxides that were initially amorphous but developed into crystalline minerals over an 8-month period and beyond; no such progression occurred in killed controls. Phylogenetic analyses of sequences from clone libraries constructed from culture DNA identified two genera known to oxidize manganese, but most clones represent previously unknown manganese oxidizers. We suggest that this community is breaking down the bedrock and accumulating iron and manganese oxides in an oligotrophic environment.     

Mesoproterozoic surface oxygenation accompanied major sedimentary manganese deposition at 1.4 and 1.1 Ga

Manganese (Mn) oxidation in marine environments requires oxygen (O₂) or other reactive oxygen species in the water column, and widespread Mn oxide deposition in ancient sedimentary rocks has long been used as a proxy for oxidation. The oxygenation of Earth's atmosphere and oceans across the Archean-Proterozoic boundary are associated with massive Mn deposits, whereas the interval from 1.8–1.0 Ga is generally believed to be a time of low atmospheric oxygen with an apparent hiatus in sedimentary Mn deposition. Here, we report geochemical and mineralogical analyses from 1.1 Ga manganiferous marine-shelf siltstones from the Bangemall Supergroup, Western Australia, which underlie recently discovered economically significant manganese deposits. Layers bearing Mn carbonate microspheres, comparable with major global Mn deposits, reveal that intense periods of sedimentary Mn deposition occurred in the late Mesoproterozoic. Iron geochemical data suggest anoxic-ferruginous seafloor conditions at the onset of Mn deposition, followed by oxic conditions in the water column as Mn deposition persisted and eventually ceased. These data imply there was spatially widespread surface oxygenation ~1.1 Ga with sufficiently oxic conditions in shelf environments to oxidize marine Mn(II). Comparable large stratiform Mn carbonate deposits also occur in ~1.4 Ga marine siltstones hosted in underlying sedimentary units. These deposits are greater or at least commensurate in scale (tonnage) to those that followed the major oxygenation transitions from the Neoproterozoic. Such a period of sedimentary manganogenesis is inconsistent with a model of persistently low O₂ throughout the entirety of the Mesoproterozoic and provides robust evidence for dynamic redox changes in the mid to late Mesoproterozoic.     

Diverse microbial communities inhabiting ferromanganese deposits in Lechuguilla and Spider Caves

Lechuguilla Cave is an ancient, deep, oligotrophic subterranean environment that contains an abundance of low-density ferromanganese deposits, the origin of which is uncertain. To assess the possibility that biotic factors may be involved in the production of these deposits and to investigate the nature of the microbial community in these materials, we carried out culture-independent, small subunit ribosomal RNA (SSU rRNA) sequence-based studies from two sites and from manganese and iron enrichment cultures inoculated with ferromanganese deposits from Lechuguilla and Spider Caves. Sequence analysis showed the presence of some organisms whose closest relatives are known iron- and manganese-oxidizing/reducing bacteria, including Hyphomicrobium, Pedomicrobium, Leptospirillum, Stenotrophomonas and Pantoea. The dominant clone types in one site grouped with mesophilic Archaea in both the Crenarchaeota and Euryarchaeota. The second site was dominated almost entirely by lactobacilli. Other clone sequences were most closely related to those of nitrite-oxidizing bacteria, nitrogen-fixing bacteria, actinomycetes and beta- and gamma-Proteobacteria. Geochemical analyses showed a fourfold enrichment of oxidized iron and manganese from bedrock to darkest ferromanganese deposits. These data support our hypothesis that microorganisms may contribute to the formation of manganese and iron oxide-rich deposits and a diverse microbial community is present in these unusual secondary mineral formations.     

pH Influences the Distribution of Microbial Rock-Weathering Phenotypes in Weathered Shale Environments

Rock varnish is a darkly pigmented coating rich in manganese oxides. Though microbes inhabit varnish deposits, it is unclear whether they are involved in varnish formation. The fungal communities of rock varnish and adjacent rock sites with no visible varnish deposits were examined. Microcolonial fungi were identified at all sampling sites, and were associated with manganese oxides in patches of incipient varnish at non-varnish sites. Fungi were closely related to manganese-oxidizing genera and seventeen isolates oxidized manganese in culture, producing six distinct manganese-oxide morphologies. Our results indicate that microcolonial fungi may play a crucial role in rock varnish formation. Supplemental materials are available for this article. Go to the publisher's online edition of Geomicrobiology Journal to view the free supplemental file.     

Deposition of manganese in a drinking water distribution system.

The deposition of manganese in a water distribution system with manganese-related "dirty water" problems was studied over a 1-year period. Four monitoring laboratories with Robbins biofilm sampling devices fitted to the water mains were used to correlate the relationship among manganese deposition, the level of manganese in the water, and the chlorination conditions. Manganese deposition occurred by both chemical and microbial processes. Chemical deposition occurred when Mn(II) not removed during water treatment penetrated the filters and entered the distribution system, where it was oxidized by chlorine and chlorine dioxide used for disinfection. Microbial deposition occurred in areas with insufficient chlorination to control the growth of manganese-depositing biofilm. At 0.05 mg of Mn(II) per liter, the chemical deposition rate was much greater than microbial deposition. Significant deposition occurred at 0.03 mg of manganese per liter, and dirty water complaints were not eliminated until manganese levels were continuously less than 0.02 mg/liter and chlorination levels were greater than 0.2 mg/liter. A guideline level of 0.01 mg of manganese per liter is recommended.     

Deposition of manganese in a drinking water distribution system

The deposition of manganese in a water distribution system with manganese-related "dirty water" problems was studied over a 1-year period. Four monitoring laboratories with Robbins biofilm sampling devices fitted to the water mains were used to correlate the relationship among manganese deposition, the level of manganese in the water, and the chlorination conditions. Manganese deposition occurred by both chemical and microbial processes. Chemical deposition occurred when Mn(II) not removed during water treatment penetrated the filters and entered the distribution system, where it was oxidized by chlorine and chlorine dioxide used for disinfection. Microbial deposition occurred in areas with insufficient chlorination to control the growth of manganese-depositing biofilm. At 0.05 mg of Mn(II) per liter, the chemical deposition rate was much greater than microbial deposition. Significant deposition occurred at 0.03 mg of manganese per liter, and dirty water complaints were not eliminated until manganese levels were continuously less than 0.02 mg/liter and chlorination levels were greater than 0.2 mg/liter. A guideline level of 0.01 mg of manganese per liter is recommended.     

Tasmanian high altitude grassy vegetation: its distribution,community composition and conservation status

Grassy woodland, grassy shrubland, grassy sedgeland, tussock grassland and grassland are extensive on basalt, limestone and fine-textured Quaternary deposits, are occasional on dolerite, granite and fine-grained sedimentary rocks, but are absent from the siliceous mountains of Tasmania. With the exception of limestone lithosols, the grassy communities are confined to relatively deep soils with a low surface rock cover. Much of the area of the grassy communities below the climatic treeline has clearly been forest in the recent past, although some of the higher subalpine plains seem likely to have been grassy at least since the peak of the Last Glacial. The first axis of an ordination of floristic data from 190 quadrats had at one extreme the grassy communities which most resembled in their species composition the sedgelands and sclerophyll shrub woodlands of the west of Tasmania, and at the other extreme the grassy woodlands on relatively fertile, well drained sites in the centre and east of Tasmania. The second axis was correlated with altitude, probably inversely reflecting the growing season. The third axis was related most closely to a soil drainage index. Many of the 15 communities recognized from a polythetic divisive classification of the quadrats have highly local distributions. Six of the communities are totally unreserved and four are poorly reserved. An iterative method is used to develop a minimum reservation strategy involving seven areas.     

Eisen und Mangan in pazifischen Tiefsee-Rhizopoden und Beziehungen zur Manganknollen-Genese Iron and Manganese in Pacific Deep-sea Rhizopods and Relationships to Manganese Nodule Formation

The Pacific deep-sea bottoms are dominated by rhizopodan Protozoa. Their abundance on manganese nodules and in the associated sediments suggests a contribution to nodule formation, though direct evidence is still lacking. Attention is called to iron contents in solid excretion products of some sessile rhizopods that may contribute to the initiation of manganese deposition and nodule growth. Manganese is scarce in the faecal pellets of sediment-dwelling rhizopods. This is discussed in context with questions regarding manganese mobilization in pelagic sediments.     

Upland interfluve (Doab) deposition: Alternative model to muddy overbank deposits

Summary Major alluvial plains contain large tracts of fine-grained muddy sediments, deposited away from the main river channels, which are mostly classed as overbank or floodplain deposits. Systematic study of the Ganga plain shows that such large tracts of deposition of muddy sediments are located several metres above the major channels, and are not flooded by overtopping of the major river channels. These surfaces are here designated as upland interfluve areas (Doab) where deposition of fine-grained sediments takes place independent of the processes operating in the main channels. The surfaces show distinct depositional domains with characteristic deposits. These include higher sloping surfaces (mottled silt), lower flat surfaces (variegated clayey silt), gulleys (sandy silt), small channels (mottled silty sand), ponds (shelly sandy clayey silt), lakes (shelly clayey silt). These deposits are prone to diagenetic changes, especially the development of calcrete horizons. Redistribution of these domains through time produces characteristic mud-dominant alluvial stratigraphy as observed in the Late Quaternary deposits of the Ganga plain. This succession shows similarity to mud-dominant deposits of the Siwalik succession. These Doab deposits are distinct from the overbank deposits formed close to the river channels affected by channel processes. It is argued that many of the thick mud-dominant fluvial deposits of the ancient fluvial record are products of deposition in upland interfluve areas.     

Pollution of a Tasmanian River by Mine Effluents I. Chemical Evidence

Discharge of effluents from tin and wolfram mines has caused severe pollution of two creeks and lesser pollution of the South Esk River in North-East Tasmania. The principal pollutants are sulphuric acid, zinc, cadmium, copper, lead, iron and manganese in dissolved or particulate form or both. The creek waters are rendered unsuitable for domestic or agricultural use and all normal biota destroyed. In the South Esk River trout are absent from polluted reaches though abundant elsewhere. Flood-borne mine tailings, rich in particulate pollutants, have destroyed or degraded pastures along the South Esk River.     

An ultrastructural study of iron and manganese deposition associated with extracellular polymers of pedomicrobium-like budding bacteria

Morphological characteristics of two Pedomicrobium-like budding bacteria are described. A structured surface layer was regularly observed on strain 868. Ruthenium red- and Alcian blue-staining polymers were found on both strains.When either strain was grown in the presence of iron or manganese, the corresponding oxides accumulated on their surfaces. In thin sections iron oxides appeared as fine threads, arrays of particles or dense coatings, depending on the source of iron. Manganese oxides appeared as branching filaments or convoluted ribbons. Both metal oxides stained with ruthenium red. Extraction of the oxides followed by ruthenium red staining revealed that polyanionic polymers previously deposited on the cells were associated with the metals.Treatment of cultures with glutaraldehyde, HgCl₂, or heat, inhibited manganese but not iron deposition, suggesting that iron oxides accumulated by passive, non-biological processes. Manganese oxides apparently accumulated under control of a biological manganese-oxidizing factor. Incomplete inhibition of manganese deposition observed in cell suspensions suggested that, if the oxidizing factor was an enzyme, it was unusually stable.Based on these results, possible mechanisms of iron and manganese deposition in association with extracellular polymers are suggested.     

Microbial Communities Inhabiting a Rare Earth Element Enriched Birnessite-Type Manganese Deposit in the Ytterby Mine,Sweden

The dominant initial phase formed during microbially mediated manganese oxidation is a poorly crystalline birnessite-type phyllomanganate. The occurrence of manganese deposits containing this mineral is of interest for increased understanding of microbial involvement in the manganese cycle. A culture independent molecular approach is used as a first step to investigate the role of microorganisms in forming rare earth element enriched birnessite-type manganese oxides, associated with water bearing rock fractures in a tunnel of the Ytterby mine, Sweden. 16S rRNA gene results show that the chemotrophic bacterial communities are diverse and include a high percentage of uncultured unclassified bacteria while archaeal diversity is low with Thaumarchaeota almost exclusively dominating the population. Ytterby clones are frequently most similar to clones isolated from subsurface environments, low temperature milieus and/or settings rich in metals. Overall, bacteria are dominant compared to archaea. Both bacterial and archaeal abundances are up to four orders of magnitude higher in manganese samples than in fracture water. Potential players in the manganese cycling are mainly found within the ferromanganese genera Hyphomicrobium and Pedomicrobium, and a group of Bacteroidetes sequences that cluster within an uncultured novel genus most closely related to the Terrimonas. This study strongly suggest that the production of the YBS deposit is microbially mediated.     

Structural features of manganese precipitating bacteria

Studies of biological communities of the past (and their associated activities) are usually dependent upon preservation of fossil material. With bacteria this rarely occurs because of the absence of sufficient fossilizable cellular material. However, some bacteria deposit metabolic products that can, conditions allowing, be preserved indefinitely. In particular, manganese and iron depositing bacteria have the capacity to form preservable microfossils. In order to better understand these microfossils of the past, we have examined present day morphologies of manganese oxidizing bacteria. These bacteria are highly pleomorphic, depending on the growth medium, the age of the culture, and the extent of manganese oxidation. Transmission electron microscopy indicates that manganese may be deposited either intra-or extra-cellularly. The prognosis of the use of morphological information for the interpretation of ancient and modern manganese deposits is discussed.Proceedings of the Fourth College Park Colloquium on Chemical Evolution:Limits of Life, University of Maryland, College Park, 18–20 October 1978.     

Structural characterization of the partially folded intermediates of an immunoglobulin light chain leading to amyloid fibrillation and amorphous aggregation

Immunoglobulin light chain deposition diseases involve various types of extracellular deposition of light chain variable domains, including amyloid fibrils and amorphous deposits. The decreased thermodynamic stability of the light chain is believed to be the major factor leading to fibrillation. However, the differences in the nature of the deposits among the light chain deposition diseases raise the question of whether the mechanisms leading to fibrillar or amorphous aggregation is different. In this study, we generated two partially folded intermediates of the light chain variable domain SMA in the presence of guanidine hydrochloride (GuHCl) and characterized their conformations. The more unfolded intermediate formed fibrils most rapidly, while the more native-like intermediate predominantly led to amorphous deposits. The results also show that the monomeric, rather than the dimeric state, was critical for fibrillation. The data also indicate that fibril elongation involves addition of a partially unfolded intermediate, rather than the native state. We postulate that a more highly unfolded intermediate is more suited to undergo the topological rearrangements necessary to form amyloid fibrils than a more structured one and that this also correlates with increased destabilization. In the case of light chain aggregation, it appears that more native-like intermediate conformations are more prone to form amorphous deposits.     

Transmission electron microscopy X-ray microanalysis of two algae of the generaScenedesmus andSiderocelis

Summary Mineral deposits have been found in the cell walls of two newly described green algae,Siderocelis minor Crawford andScenedesmus granulatus West et West f.salina Crawford. A morphological account using transmission electron microscopy coupled with X-ray micro-analysis has shown that the deposits consist chiefly of iron and manganese though other elements were also found. Several possible explanations have been suggested for the variation in iron/manganese ratio—the ecological conditions pertaining in the natural habitat being considered particularly relevant.     

Development of a species-specific gene probe for Hyphomicrobium facilis with the inverse PCR.

A species-specific gene probe for Hyphomicrobium facilis was generated from a transposon Tn5-132 insertion mutant defective in methanol oxidation by the inverse PCR. With this probe, the abundance of H. facilis in a garden soil was determined as a subfraction of the total cultivable hyphomicrobia.