Lampropedia Hyalina Research Articles

Lampropedia cohaerens sp. nov., a biofilm-forming bacterium isolated from microbial mats of a hot water spring, and emended description of the genus Lampropedia.

A biofilm-forming, Gram-stain-negative, aerobic, catalase-positive but oxidase-negative strain, designated CT6T, was isolated from the microbial mats (∼45 °C) of a hot water spring, located within the Himalayan ranges at Manikaran, Himachal Pradesh, India. Strain CT6T formed white, smooth colonies with irregular margins. Transmission electron microscopy revealed coccoid, non-flagellated cells with wavy boundaries. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain CT6T belongs to the genus Lampropedia with a sequence similarity value of 95.4 % to the sole member of this genus, Lampropedia hyalina ATCC 11041T. Strain CT6T was found to have phosphatidylethanolamine and phosphatidylglycerol as the major polar lipids. The major cellular fatty acids were C16 : 0, summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), C14 : 0, C19 : 0ω8c cyclo and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c). The major respiratory quinone was ubiquinone-8. The major polyamines were putrescine, spermidine and the betaproteobacterial-specific 2-hydroxyputrescine. The DNA G+C content was 63.5 mol%. Based on the genotypic, phenotypic, physiological and biochemical data, strain CT6T is considered to represent a novel species of the genus Lampropedia, for which the name Lampropedia cohaerens sp. nov. is proposed ( = DSM 100029T = KCTC 42939T = MCC 2711T).

Lampropedia puyangensis sp. nov., isolated from symptomatic bark of Populus × euramericana canker and emended description of Lampropedia hyalina (Ehrenberg 1832) Lee et al. 2004.

A Gram-stain negative, Neisser-stain negative, aerobic, non-motile, non-spore-forming, slimy, glossy bacterial strain with single or clustered coccoid cells and white colony colour, designated as 2-bin(T), was isolated from cankered bark tissue of Populus×euramericana. The strain was found to grow at 15-40°C and pH 5-10, with an optimum of 30°C and pH 8.0. The strain was found to be negative with respect to catalase and positive for oxidase activity, nitrate reduction and Voges-Proskauer reaction. Analysis of 16S rRNA gene sequence data indicated that the isolate belongs to the genus Lampropedia, having sequence similarity of 96.24% with Lampropedia hyalina ATCC11041(T). DNA-DNA relatedness of strain 2-bin(T) with L. hyalina JCM 21380(T) was 26.7±4.6%. The DNA G+C content of strain 2-bin(T) was determined to be 57% and the major cellular fatty acids were identified as C16:0, C16:1 ω7c/C16:1 ω6c and C18:1 ω7c. The polar lipid profile of strain 2-bin(T) was found to contain diphosphatidylglycerol, a glycolipid, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, a phospholipid, phosphatidylmonomethylethanolamine and three unidentified lipids (L1, L2, L3). Based on molecular data and physiological and biochemical characteristics, strain 2-bin(T) is considered to represent a novel species in the genus Lampropedia, for which the name Lampropedia puyangensis sp. nov. is proposed. The type strain is 2-bin(T) (=CFCC 10925(T)=KCTC 32235(T)).

Sequencing Analysis of HA-A/A-MCO Process

This study applies PCR-DGGE fingerprinting technique to analysis the bacterial community structure of phosphorous removal and denitrification system. Through strains identification, it is found that acinetobacter sp.is the base of keeping favorable phosphorus removal effect, Spirochaeta sp.undertakes the function of organic matters removal, Bacillus sp. and Lampropedia hyalina sp.can propagate largely in the germiculture area(No.1 oxic tank), and can be preyed on by highlevel microbe(such as protozoa and metazoan) in protozoa growing area(No.2oxic tank) and metazoan growimg area(No.3 oxic tank). The predation between highlevel microbe and low grade microbe can promote efficient sludge reduction of HA-A/A-MCO process.

Effect of pH on the production of bacterial polyhydroxyalkanoates by mixed cultures enriched under periodic feeding

This research investigated the effect of pH on polyhydroxyalkanoate (PHA) production by mixed cultures enriched in a sequencing batch reactor (SBR) starting from activated sludge. The enrichment was performed with a mixture of acetic (85% on COD basis) and propionic (15%) acid, at an organic load rate of 8.5 gCOD/L/day over the range of pH from 7.5 to 9.5. The enriched cultures were all able to store the copolymer poly(3-hydroxybutyrate/3-hydroxyvalerate). Higher polymer production rates and yields (389 mg PHA (as COD)/g non-polymer biomass (as COD)/h and 0.53 COD/COD, respectively) were observed when the pH in the SBR was controlled at 7.5, with Lampropedia hyalina as the dominant bacterial species of the microbial community. PHA composition was also strongly affected by the pH. Indeed, batch tests showed that hydroxyvalerate (HV) content in the copolymer increased with increasing pH up to about 48% (mol/mol) at pH 9.5. Interestingly, the possibility of enhancing the HV content was also verified by performing batch tests at a more alkaline pH value than that in the SBR. In conclusion, this paper suggests that pH control is a main tool to tune HV content in the PHA, regardless of the feed composition.

Exploiting olive oil mill effluents as a renewable resource for production of biodegradable polymers through a combined anaerobic–aerobic process

AbstractBACKGROUND: The performance of a three‐stage process for polyhydroxyalkanoate (PHA) bioproduction from olive oil mill effluents (OME) has been investigated. In the first anaerobic stage OME were fermented in a packed bed biofilm reactor into volatile fatty acids (VFAs). This VFA‐rich effluent was fed to the second stage, operated in an aerobic sequencing batch reactor (SBR), to enrich mixed cultures able to store PHAs. Finally, the storage response of the selected consortia was exploited in the third aerobic stage, operated in batch conditions.RESULTS: The anaerobic stage increased the VFA percentage in the OME from 18% to ∼32% of the overall chemical oxygen demand (COD). A biomass with high storage response was successfully enriched in the SBR fed with the fermented OME at an organic load rate of 8.5 gCOD L−1 d−1, with maximum storage rate and yield (146 mgCOD gCOD−1 h−1 and 0.36 COD COD−1, respectively) very similar to those obtained with a synthetic VFA mixture. By means of denaturing gradient gel electrophoresis (DGGE) analysis, different bacterial strains were identified during the two SBR runs: Lampropedia hyalina and Candidatus Meganema perideroedes, with the synthetic feed or the fermented OMEs, respectively. In the third stage, operated at increasing loads, the maximum concentration of the PHA produced increased linearly with the substrate fed. Moreover, about half of the stored PHAs were produced from substrates other than VFAs, mostly alcohols.CONCLUSION: The results obtained indicate that the process is effective for simultaneous treatment of OME and their valorization as a renewable resource for PHA production. Copyright © 2009 Society of Chemical Industry

Emended description of the species Lampropedia hyalina.

Three Lampropedia hyalina strains from different habitats were compared by phenotypic, chemotaxonomic and molecular characteristics. All strains form coccoid cells and have been reported to grow as square tablets of eight to 64 cells. However, two of these strains (ATCC 11041T and ATCC 43383) have apparently lost this ability, and the third strain may temporarily lose this capacity under certain cultivation conditions. The three strains showed only minor differences in metabolic characteristics: the main significant physiological difference was the ability to accumulate polyphosphate under alternating anaerobic-aerobic conditions found for DSM 15336. The three strains showed high similarity in fatty acid composition and only slight differences in the G + C content (63-67 mol%) and DNA-DNA reassociation (90-95 % relatedness). Comparative 16S rRNA gene sequence analyses on these three strains and three Lampropedia hyalina 16S rRNA gene sequences deposited at NCBI showed that they are all very similar (> 98.8 %) and that they form a distinct group among the 'Betaproteobacteria', showing between 94.6 and 93 % 16S rRNA gene similarity to members of various genera such as Acidovorax, Aquaspirillum, Brachymonas, Comamonas, Delftia and Xenophilus. Fluorescent in situ hybridization with oligonucleotide probes targeting betaproteobacteria on the 16S rRNA and 23S rRNA gene level further supported the conclusion that all investigated strains are members of the 'Betaproteobacteria'. Two oligonucleotide probes were designed and successfully applied for culture-independent identification of Lampropedia hyalina by means of fluorescent in situ hybridization.

Phylogenetic analyses of Lampropedia hyalina based on the 16S rRNA gene sequence.

Phylogenetic analyses of Lampropedia hyalina based on the 16S rRNA gene sequence.

Structural analysis of the S-Layer of Lampropedia hyalina

The two-dimensional (2D) structure of the regularly structured surface layer (S-layer) of the gram-negative eubacterium Lampropedia hyalina has been determined at the molecular level to a nominal resolution of 2.1 nm by transmission electron microscopy and digital image processing. The inner, or “perforate,” layer consists of dimeric block-shaped units located at two-fold symmetry axes. These morphological dimers associate around three-fold symmetry axes to form a continuous layer with p6 symmetry and a lattice constant of 14.6 ± 0.4 nm. Scanning transmission electron microscopy (STEM) yields a mass-per-area (MPA) value for the perforate layer of 3.5 kDa/nm 2. The outer, or “punctate,” layer is composed of long, roughly cylindrical units centered on six-fold symmetry axes, which are connected by six fine linking arms joining at the three-fold symmetry axes to create a hexagonal layer with a lattice constant of 25.6 ± 0.5 nm. The MPA of the “composite”-i.e., perforate plus punctate—layer is 10.2 kDa/nm 2.

The perforate component of the regularly structured (RS) layer of Lampropedia hyalina

The regularly structured (RS) layer of Lampropedia hyalina was found to consist of two components; of these, the inner perforate layer was easily isolated from cell envelopes by dissolution of attached material by incubation in 2% sodium dodecyl sulfate at room temperature. The layer consisted of a 31.5-kilodalton polypeptide arranged in p6 symmetry so that, in negative stain, it appeared to be a sheet full of regularly arranged holes with a repeat frequency of 13 nm. The layer was stable in chelating and reducing agents, and in various detergents. Dissolution of the perforate layer occurred in boiling sodium dodecyl sulfate, 6 M guanidine–HCl, 8 M urea, 90% formic acid, and in buffers below pH 4 and above pH 11. In its dissociated state, the component polypeptide was sensitive to hydrolysis by endoproteinase glu-C, while the assembled polypeptide was not affected, suggesting that the acidic amino acid residues are hidden from the protease in the assembled state.

Physiology and nutrition of Lampropedia hyalina.

A detailed study of the physiology and nutrition of Lampropedia hyalina revealed that it is an aerobic, cytochrome-containing chemoheterotroph which is limited in its energy sources to a few intermediates (and close derivatives) of the Krebs cycle. Reducing compounds at low levels are potent growth inhibitors. The microbe has no photosynthetic ability (despite its previous taxonomic position with the sulfur purple bacteria). The results of a general investigation of its physiology are reported. Added biotin and thiamine are needed for growth in defined media; pantothenate is strongly stimulatory. Alanine, arginine, and tyrosine, as well as NH(4)Cl, serve as sole nitrogen sources. A unique motion exhibited by cells of a rapidly growing culture is described. Aspects of its metabolism of poly-beta-hydroxybutyrate and limiting aspects of its physiology as related to its ecology are discussed.

Clonal morphogenesis of Lampropedia hyalina.

The characteristic arrangement of the cells of Lampropedia hyalina in rectangular sheets makes this bacterium an attractive model for studying clonal morphogenesis. In micro-slide cultures, clones develop from a single cell by growing and dividing along two parallel sets of growth axes, synchronized alternately by 90 degrees. The formation of the intracytoplasmic granules, chemically identified as poly-β-hydroxybutyric acid, also follows this pattern. One predominant granule occurs in each cell under “standard” cultural conditions (1.0% Difco yeast extract, 30°C), and formation of new polymer granules precedes division of the cell. The variation of environmental factors-such as pH in the presence of phosphate, nutrient concentration, and temperature-disturbs greatly the regular pattern of morphogenesis and cytogenesis in Lampropedia. This disarray includes an increase in the number of granules per cell; excessive amounts of polymer; distention and lysis of cells; disorderly arrangement of cells.

THE SURFACE ANATOMY OF LAMPROPEDIA HYALINA.

The fine structure of the superficial layers of the tablet-forming micro-organism, Lampropedia hyalina , has been studied by several electron microscopical techniques. The outer envelope is distinct from the cell wall and surrounds not individual cells but groups of cells (tablets). This envelope appears to embody two complex layers, both possessing a regular-patterned structure. One layer (the perforate layer) is a honeycomb network of hexagonally distributed holes, each about 75 Å in diameter, and with a repeat spacing, from centre to centre, of 145 Å. The other, outermost (punctate) layer, which seems to be fragile and easily lost, is composed of outward-projecting spines, also in hexagonal array but with a repeat spacing of 260 Å. The probable structural relationship between the perforate and punctate layers is discussed. The structured envelope is separated from the cells by an amorphous zone (the intercalated zone) about 600 Å thick; this penetrates between the cells of a tablet and follows immediately behind the ingrowing septum in cell division. The intercalated zone is probably the important factor in cell cohesion; the significance of the structured envelope is uncertain but its function may be to separate the sheet into tablets by preventing intercell cohesion at certain places in what would otherwise be a continuous sheet of cells.

ROLE OF SUPERFICIAL STRUCTURES IN THE CHARACTERISTIC MORPHOLOGY OF LAMPROPEDIA HYALINA

A strain of Lampropedia hyalina (A.T.C.C. 11041) has lost the ability to form the tablets of cells and sheets. In fact, it has lost the characters that give it generic status and allow its identification. Detailed comparison with a sheeting strain of the species indicates that what is lost is an intercalated layer, which glues together the cells of the tablet, and the outermost of the two structured layers which form the surface envelope. Both of these elisions may be important to tablet formation but the former is probably the most important. There is evidence that these layers may still be retained on occasional cells as small islands of material in the appropriate anatomical regions. However, although these islands must reproduce and be perpetuated in the strain, there is no evidence that the layers can be fully recovered and no fully characteristic Lampropedia have been isolated from the mutilated strain.

Lampropedia hyalina Schroeter 1886 and Vannielia aggregata n.g., n.sp., with remarks on natural and on organized colonies in bacteria.

SUMMARY: Two bacteria, Lampropedia hyalina and Vannielia aggregata, are described, which form characteristically shaped aggregations. The differences between artificial, natural and organized colonies are discussed.