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Bibliographic Information
Bacterium for nitrite oxidation in waters. Hovanec, Timothy A. (Aquaria Inc., USA). PCT Int. Appl. (1999), 65 pp. CODEN: PIXXD2 WO 9932603 A1 19990701 Application: WO 98-US27196 19981221. Priority: US 97-68492 19971222. CAN 131:77804 AN 1999:421758
Abstract
An isolated bacterial strain capable of oxidizing nitrite to nitrate is described contg. a 16S rDNA nucleotide sequence ³95% similar or identical to SEQ ID NO:1 (GenBank database AF035813). The strain is clone 710-9. The Nitrospira-like bacterium can be used for nitrification-denitrification of waters, in combination with microorganisms which oxidize ammonia and reduce nitrates. Applications include freshwater or seawater aquariums or wastewaters.
THESE OTHERS ARE PAPERS:
Compositional changes in free-living bacterial communities along a salinity gradient in two temperate estuaries. Bouvier, Thierry C.; del Giorgio, Paul A. Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, MD, USA. Limnology and Oceanography (2002), 47(2), 453-470.
There is clear evidence for major differences in heterotrophic bacterial compn. between freshwater and marine ecosystems. A fundamental, unresolved question is whether compositional succession occurs by a gradual replacement of major phylotypes, or whether there are drastic compositional shifts in discrete areas along the gradient from 1 system to another. This study examd. changes in the phylogenetic compn. of free-living bacterioplankton across a salinity gradient in the Choptank and Pocomoke rivers, both sub-estuaries of Chesapeake Bay, using fluorescence in-situ hybridization (FISH). The proportion of free-living cells detected using FISH varied widely (3-80%); the majority of cells detected belonged to bacteria, whereas Archaea represented <3%. Distribution of the different members of bacteria exhibited a clear pattern along the salinity gradient, dominated by a-proteobacteria in the lower, salt water regions and by b-proteobacteria in the upper, freshwater regions. The Cytophaga-Flavobacterium cluster prevailed in the turbidity max. in the middle estuary, and g-proteobacteria showed sporadic peaks along the transect which may be related to local events. Replacing a- for b-proteobacteria along the salinity gradient was not gradual; it occurred rapidly within the turbidity max. region of estuaries where freshwater and salt water mix. The phylogenetic succession pattern was linked to development of the turbidity max., which was related to rainfall and ensuing hydrol. conditions. There was indication that phylogenetic succession is accompanied by strong physiol. changes in the bacterial assemblage, expressed as a decline in bacterial growth efficiency and community prodn. The transition does not appear to be simply the result of conservative mixing of riverine and estuarine bacterial assemblages, but rather involves cell inactivation and/or death.
The influence of natural salinity gradients on bacteria communities of flowing waters. Rheinheimer, Gerhard. Institut Meereskunde, Kiel, Germany. Limnologica (1997), 27(1), 29-35.
Abstract
Investigations were performed in the Elbe estuary, the Kiel Canal, in a river mouth of the western Baltic Sea, and the Schlei Fjord (Germany). It was demonstrated that the compn. of the bacteria communities was strongly correlated with salinity changes. Increasing salinities caused an increase of the generation time, and rather frequently, also changes of cell morphol. Expts. with natural freshwater bacteria communities and a "reduced community" of isolates from the Schwentine river showed the influence of higher salinities on the activity of these river bacteria. A regrouping of the community took place in brackish water and seawater. Particularly in polluted rivers and in coastal waters facultative osmophilic bacteria played a role in self-purifn.
Comparison of the molecular diversity of the methanogenic community at the brackish and marine ends of a UK estuary. Purdy, Kevin J.; Munson, Mark A.; Nedwell, David B.; Embley, T. Martin. Department of Biological Science, University of Essex, Colchester, Essex, UK. FEMS Microbiology Ecology (2002), 39(1), 17-21.
Abstract
The 16S rRNA sequence diversity of the euryarchaeal community in a predominately freshwater sediment at East Hill Bridge (EHB) on the River Colne estuary, Essex, UK was investigated and compared to that from marine sediments at the mouth of the river (Colne Point). The East Hill Bridge sediments appear to support the full range of methanogen phenotypes with some genotypes similar to those previously detected at Colne Point. However, no Marine Benthic Group D or halophilic archaeal genotypes, both abundant in gene libraries at Colne Point, were detected at East Hill Bridge. Clones related to Methanosarcina and Methanocorpusculum were detected only at East Hill Bridge while clones closely related to Methanoculleus and Methanococcoides were detected only at Colne Point. The most common clones in the East Hill Bridge library were closely related to the obligate acetate-utilizing Methanosaeta concilii, suggesting they may be important methanogens in these sediments. Clones that group closely with M. concilii appear to be ubiquitous in freshwater sediments and we suggest that they are prime candidates for a globally important acetoclastic methanogenic group. The distribution of clones in the East Hill Bridge and Colne Point libraries implies that certain methanogen groups are generalists, adapted to the range of conditions within an estuarine environment (e.g. Methanogenium) while others are more specialist (e.g. Methanosaeta).
True marine and halophilic anoxygenic phototrophic bacteria. Imhoff, Johannes F. Marine Mikrobiologie, Institut fur Meereskunde Kiel, Kiel, Germany. Archives of Microbiology (2001), 176(4), 243-254.
Abstract
A review. Anoxygenic phototrophic bacteria are widely distributed in marine sediments and shallow waters of the coastal zone, where they often form intensely colored mass developments. The phototrophic bacteria have adapted to the whole spectrum of salt concns., from freshwater to satd. brines, and it is apparent that individual species have adapted well to particular habitats and mineral salts compns., both qual. and quant. This adaptation is reflected not only in the demand for defined ranges of salt concns., but also in the phylogenetic relationships of these bacteria, as established by 16S rDNA sequences. Major phylogenetic branches of purple sulfur bacteria are represented by: (1) marine and extremely halophilic Ectothiorhodospiraceae, (2) truly marine and halophilic Chromatiaceae and (3) freshwater Chromatiaceae, some of which are tolerant to low salt concns. and are successful competitors in brackish and marine habitats. Quite similarly, salt-dependent green sulfur bacteria form distinct phylogenetic lines. In addn., also among the phototrophic a-Proteobacteria (purple nonsulfur bacteria), distinct phylogenetic lines of salt-dependent species are recognized. Available data give rise to the assumption that salt concns. of natural habitats are an important selective factor that dets. the development of a selected range of phototrophic bacteria in an exclusive way. As a consequence, the salt responses of these bacteria are reflected in their phylogenetic relationships.
Phylogenetic comparisons of a coastal bacterioplankton community with its counterparts in open ocean and freshwater systems. Rappe, M. S.; Vergin, K.; Giovannoni, S. J. Department of Microbiology, Oregon State University, Corvallis, OR, USA. FEMS Microbiology Ecology (2000), 33(3), 219-232.
Abstract
In order to extend previous comparisons between coastal marine bacterioplankton communities and their open ocean and freshwater counterparts, here we summarize and provide new data on a clone library of 105 SSU rRNA genes recovered from seawater collected over the western continental shelf of the USA in the Pacific Ocean. Comparisons to previously published data revealed that this coastal bacterioplankton clone library was dominated by SSU rRNA gene phylotypes originally described from surface waters of the open ocean, but also revealed unique SSU rRNA gene lineages of b-Proteobacteria related to those found in clone libraries from freshwater habitats. b-Proteobacteria lineages common to coastal and freshwater samples included members of a clade of obligately methylotrophic bacteria, SSU rRNA genes affiliated with Xylophilus ampelinus, and a clade related to the genus Duganella. In addn., SSU rRNA genes were recovered from such previously recognized marine bacterioplankton SSU rRNA gene clone clusters as the SAR86, SAR11, and SAR116 clusters within the class Proteobacteria, the Roseobacter clade of the a subclass of the Proteobacteria, the marine group A/SAR406 cluster, and the marine Actinobacteria clade. Overall, these results support and extend previous observations concerning the global distribution of several marine planktonic prokaryote SSU rRNA gene phylotypes, but also show that coastal bacterioplankton communities contain SSU rRNA gene lineages (and presumably bacterioplankton) shown previously to be prevalent in freshwater habitats.
Contrasts between marine and freshwater bacterial community composition: analyses of communities in Lake George and six other Adirondack lakes. Methe, Barbara A.; Hiorns, William D.; Zehr, Jonathan P. Darrin Fresh Water Institute Rensselaer Polytechnic Institute, Troy, NY, USA. Limnology and Oceanography (1998), 43(2), 368-374.
Abstract
The bacterial communities of 7 freshwater lakes in the Adirondack Mountains of New York state were examd. using culture-independent methods. b-Proteobacteria 16S rRNA sequences were recovered from all 7 lakes and their presence was confirmed by direct DNA hybridization. The results are consistent with phylogenetic and in situ hybridization-based studies in other freshwater environments, but are significantly different than the results of marine oceanic studies, where b-Proteobacteria are noticeably absent. This relation between evolutionary history and environmental distribution is striking, since these phylogenetic clades have not been correlated with consistent physiol. features or biochem. capabilities, and there is no a priori reason to expect differences in phylogenetic compn. between the environments. In contrast, freshwater relatives to marine phylogenetic clusters, in particular the SAR 11 cluster of the a-Proteobacteria, were identified. The data imply an underlying physiol. distinction between the b- and other Proteobacteria groups and potentially an important difference between the compn. of bacterial communities in marine and freshwater environments.
L.E Si inca ceva despre "seeding"
Accelerated nitrification in new seawater culture systems: effectiveness of commercial additives and seed media from established systems. Bower, Carol E.; Turner, David T. Sea Res. Found., Inst. Aquarium Stud., West Hartford, CT, USA. Aquaculture (1981), 24(1-2), 1-9.
Abstract
The conditioning period or time required to establish nitrification in new seawater culture systems was reduced substantially or eliminated after seeding with various media from established seawater aquariums. The relative effectiveness of the seed media was: 10% wet filtrant > 5% wet filtrant > 20% seawater > 10% dry filtrant. The introduction of com. additives contg. nitrifying bacteria or of filtrant from an established freshwater culture system did not accelerate the nitrification sequence in new seawater aquariums.
P.S Eu nu vreau sa intru in vreo polemica
, am gasit astea si am zis sa vi le arat, toate articolele sunt prezentate de Randy Holmes-Farley