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Cyanobacterial blooms in lakes frequently display high spatial heterogeneity, which may drive temporal changes in microbial community structure. Here we report on the spatial (horizontal and vertical) structure of the cyanobacteria community and of the co‐occurring heterotroph microbial community during a major lake‐wide bloom event at Lake Kinneret (Sea of Galilee, Israel).We sampled the upper water layer (0, 1 and 5 m depths) at five locations across the lake, spatially representing north, south, east, west and centre of the lake, on two dates during winter 2016 when the Microcystis biomass was high. We aimed to characterise the spatial distribution of the bloom and the associated microbiota, as well as testing the extent to which variation in the structure of the microbial community could be associated with Microcystis biomass.During the winter 2016 bloom, Microcystis biomass was spatially heterogeneous, but the Microcystis population structure was rather homogenous, dominated by a single genotype (ITS sequence variant). By contrast, the composition of the bacterial community, assessed using 16S rRNA gene sequencing, was spatially heterogeneous, differing between depths, sampling locations and time.The largest difference in microbial community structure was between particle‐associated (PA) and free‐living (FL) fractions. The PA community was characterised by a relatively lower diversity, and dominated by Proteobacteria, whereas the FL community was significantly more diverse and dominated by members of Proteobacteria, Bacteroidetes and Actinobacteria. Variation in the microbial community was significantly correlated with geographical location and sampling depth. However, there was no clear relationship between the Microcystis biomass density (cells biovolume) and the structure of the microbial communities.These results suggest that the structure of the bacterial community is partly decoupled from Microcystis population density, and potentially more affected by other environmental factors such as temperature and/or physicochemical conditions. Our study highlights the importance of spatial information on bloom composition and intensity in clarifying the factors affecting the progression of cyanobacterial harmful algal blooms and how this impacts their microbial counterparts. [ABSTRACT FROM AUTHOR]

The lakeshore habitat, which is an interface zone between lake and land, harbours various organic particles providing nutrient‐rich microhabitats for bacterial colonisation. Revealing the mechanisms maintaining the bacterial diversity generated on these particles is vital for understanding the biogeochemical processes within lakeshore habitats. To date, however, the bacterial communities within lakeshore habitats have been rarely explored, and knowledge of the ecological processes associated with their spatial distribution is limited.Here, we employed amplicon‐based high throughput sequencing technology to investigate the composition, co‐occurrence patterns, spatial distribution, and assembly processes of free‐living and particle‐attached bacterial communities (FLBC vs. PABC) across 29 lakeshore zones within freshwater lakes from two typical regions: Middle–Lower Yangtze River Plain and Yunnan–Kweichow Plateau.We found significant community dissimilarity between both bacterial lifestyles and regions. PABC exhibited higher community dissimilarity between the plain and plateau regions than FLBC did. Furthermore, eight operational taxonomic units were detected as a core bacterial community within the lakeshore habitats across the plain and plateau regions. Network analysis revealed that bacterial taxa preferring a particle‐attached lifestyle exhibited more co‐occurrence associations for both intra‐ and inter‐community than the free‐living lifestyle. Both FLBC and PABC showed significant distance–decay relationships in these two regions. Dispersal limitation was the most important process associated with patterns in the spatial distribution of FLBC and PABC, whereas the relative importance of variable and homogeneous selection differed between the assembly of FLBC and PABC because of differences in their microhabitats.Our results highlight that dispersal limitation may be strongly associated with the spatial distribution of lakeshore bacterial communities at a regional scale. However, lifestyle differences influence the relative balance between the processes of dispersal, selection, and biotic interaction that influence these bacterial communities.This study reveals potential interactions between bacterial taxa with different lifestyles as well as indicating which ecological processes may lie behind the spatial distribution of bacterial communities in lakeshore habitats. Knowledge of potential assembly mechanisms of bacterial communities within different microhabitats help us understand how bacterial communities in different microhabitats are generated and their different roles in biogeochemical processes in lakeshore habitats. [ABSTRACT FROM AUTHOR]

This overview deals with freshwater actinobacteria (one of the dominant groups of the heterotrophic bacterioplankton), their biology and ecology, and their role in cycling some of the main biogenic elements and in the transformation of recalcitrant organic compounds in freshwater reservoirs. The most distinctive features of the most abundant groups of planktonic freshwater actinobacteria, methods of isolation, obtaining pure cultures, and further cultivation have been considered. The general and individual ecophysiological, phenotypic, genotypic, and metabolic characteristics are given. [ABSTRACT FROM AUTHOR]

Understanding the successional patterns of microbial communities during a phytoplankton bloom is crucial for predicting the compositional and functional stability of lake ecosystems in response to the disturbance of a bloom. Previous studies on bacterial communities associated with blooms have rarely studied the dynamics of these communities. The successional patterns of bacterial communities within different micro‐habitats (i.e. water column versus particles) and mechanisms that shape these communities that differ in composition and structure remain unclear.We selected a eutrophic urban lake to investigate the succession of bacterial communities during a bloom. We divided the bacterial communities into free‐living (FL) and particle‐attached (PA) groups based on their different lifestyles. The amplicon‐based 16S rRNA gene high‐throughput sequencing technology was used to obtain bacterial community composition and phylogenetic structure.Our study showed distinct successional patterns between FL and PA bacterial communities, and the two bacterial lifestyles showed different responses and resilience to the bloom, in terms of diversity and relative abundance of bacterial taxa. Alpha‐diversity of the PA bacterial community decreased during the bloom, whereas that of the FL bacterial community increased. More taxa in the FL bacterial community showed resilience after the disturbance than in the PA bacterial community.The influence of phytoplankton blooms on the assembly of the bacterial community can be viewed as niche selection that led to the decrease in the relative importance of stochastic processes in shaping both FL and PA bacterial communities. This study shows the ecological significance of the bacterial community response to bloom events in lakes. It also shows that assembly processes differ for bacterial communities that have different lifestyles in lake ecosystems disturbed by phytoplankton blooms. [ABSTRACT FROM AUTHOR]

Based on a three-year study on the prokaryotic community composition in peat bog lakes surrounded by a floating mat of Sphagnum sp. moss in the conditions of Northeast Poland (Central Europe), we verified the relationship between 20 water parameters and main Eubacteria and Archaea phyla for specific sites: the subsurface (pelagic zone), near-bottom (benthic zone), and the Sphagnum mat (ecotone zone). Abundance and composition of the main aquatic bacteria phyla (Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Deltaproteobacteria, Actinobacteria, and Cytophaga-Flavobacteria) and Archaea were associated with different combinations of physico-chemical parameters of water, and followed temporal variations of temperature, dissolved organic carbon (DOC), aromaticity, and water color. Redundancy analysis (RDA) showed that water acidity is a less significant predictor of bacterial activity; however, we have found Betaproteobacteria negatively correlated (r = −0.49, p = 0.01), while Actinobacteria positively correlated (r = 0.21, p = 0.05) to pH. This relation was the most significant in the ecotone zone. In the overall bacteria community structure Betaproteobacteria dominated (18.3%) regardless of site or season, except for winter when, at low temperatures and DOC concentrations, Actinobacteria increased to 22.9%. The Archaea fraction was uniform (11%) in seasons and sites and showed no specific preferences to physico-chemical predictors. Although the water parameters from the Sphagnum mat did not differ significantly from pelagic water, its role as a source of allochthonous organic matter is crucial for bacteria activity. The relations between peat bog lake attributes and seasonal changes in bacterial diversity demonstrated a distinct divergent pattern for each prokaryote. Obtaining results will provide support for any future evaluation of the effects of environmental variables on prokaryotic community structures in peat bog lakes [ABSTRACT FROM AUTHOR]

Bacteria assemblages in lake sediments play a key role in various biogeochemical processes, yet their association with interstitial pore waters has been scarcely investigated. In this study, we utilized Illumina next-generation amplicon sequencing of the 16S rRNA gene to characterize the seasonal bacterial communities in the sediments and pore waters of three contrasted temperate freshwater lakes, namely Pavin, Aydat, and Grangent (French Massif Central). Despite occupying seemingly similar habitats, bacterial communities differed substantially between sediments and pore waters at all seasons with low sharing of operational taxonomic units (OTUs, 6.7 to 20.3%) between them. Sediment-associated bacteria were more rich and diverse than pore water bacteria, indicating a high heterogeneity in the sediment microhabitat. The changes in both sediment and pore water bacterial communities were lake and season specific. The bacterial community showed distinct differences between the lakes, with larger presence of strict anaerobes such as Syntrophus, Syntrophorhabdus, and Sulfuricurvum in the pore water and sediments of Pavin responsible for carbon and sulfur cycling. In both Aydat and Grangent, the hgcI_clade dominated throughout the study period in the pore waters. The higher representation of lesser-known transient members of lake communities such as Methylotenera in the pore waters of Aydat, and Clostridium and Sulfuricurvum in the pore and sediments of Grangent, respectively, were observed during the period of temporary anoxia in summer caused by lake stratification. Our study revealed that in the investigated lakes, the prevailing environmental factors across time and space structured and influenced the adaptation of bacterial communities to specific ecological niches. [ABSTRACT FROM AUTHOR]

We investigated changes in quality and quantity of extracellular and biomass-derived organic matter (OM) from three axenic algae (genera Rhodomonas, Chlamydomonas, Coelastrum) during growth of Limnohabitans parvus, Limnohabitans planktonicus and Polynucleobacter acidiphobus representing important clusters of freshwater planktonic Betaproteobacteria. Total extracellular and biomass-derived OM concentrations from each alga were approximately 20 mg l−1 and 1 mg l−1 respectively, from which up to 9% could be identified as free carbohydrates, polyamines, or free and combined amino acids. Carbohydrates represented 54%-61% of identified compounds of the extracellular OM from each alga. In biomass-derived OM of Rhodomonas and Chlamydomonas 71%-77% were amino acids and polyamines, while in that of Coelastrum 85% were carbohydrates. All bacteria grew on alga-derived OM of Coelastrum, whereas only Limnohabitans strains grew on OM from Rhodomonas and Chlamydomonas. Bacteria consumed 24%-76% and 38%-82% of all identified extracellular and biomass-derived OM compounds respectively, and their consumption was proportional to the concentration of each OM compound in the different treatments. The bacterial biomass yield was higher than the total identifiable OM consumption indicating that bacteria also utilized other unidentified alga-derived OM compounds. Bacteria, however, also produced specific OM compounds suggesting enzymatic polymer degradation or de novo exudation. [ABSTRACT FROM AUTHOR]

The Mississippi River (MR) serves as the primary source of freshwater and nutrients to the northern Gulf of Mexico (nGOM). Whether this input of freshwater also enriches microbial diversity as the MR plume migrates and mixes with the nGOM serves as the central question addressed herein. Specifically, in this study physicochemical properties and planktonic microbial community composition and diversity was determined using iTag sequencing of 16S rRNA genes in 23 samples collected along a salinity (and nutrient) gradient from the mouth of the MR, in the MR plume, in the canyon, at the Deepwater Horizon wellhead and out to the loop current. Analysis of these datasets revealed that the MR influenced microbial diversity as far offshore as the Deepwater Horizon wellhead. The MR had the highest microbial diversity, which decreased with increasing salinity. MR bacterioplankton communities were distinct compared to the nGOM, particularly in the surface where Actinobacteria and Proteobacteria dominated, while the deeper MR was also enriched in Thaumarchaeota. Statistical analyses revealed that nutrients input by the MR, along with salinity and depth, were the primary drivers in structuring the microbial communities. These results suggested that the reduced salinity, nutrient enriched MR plume could act as a seed bank for microbial diversity as it mixes with the nGOM. Whether introduced microorganisms are active at higher salinities than freshwater would determine if this seed bank for microbial diversity is ecologically significant. Alternatively, microorganisms that are physiologically restricted to freshwater habitats that are entrained in the plume could be used as tracers for freshwater input to the marine environment. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Microbiology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Understanding how resource partitioning works among taxa is crucial in explaining coexistence and competition within a community. Here, we assessed resource partitioning among freshwater bacterial groups from two oligotrophic lakes using four types of organic substrates as compound models. Substrate uptake patterns were examined by microautoradiography combined with catalysed reporter deposition fluorescent in situ hybridization. Four large taxonomic groups were found in the lakes, but A ctinobacteria ( AcI lineage) and B etaproteobacteria ( R- BTcluster) dominated the bacterial assemblage. Monomers containing nitrogen and/or phosphorus were preferred over the ones containing only carbon. All groups were able to incorporate amino acids, adenosine triphosphate and glucose. However, acetate was only taken up by ∼ 10-12% of bacteria, and its uptake was not detected in C ytophaga- F lavobacteria. Apart from acetate, the contribution of a particular bacterial group to the uptake of a substrate was proportional to its relative abundance. In both lakes, we detected substrate partitioning between AcI Actinobacteria, which was overrepresented in glucose and acetate utilization, and R- BT B etaproteobacteria, which dominated amino acid uptake. Our results strongly point to physiological niche separation of those bacterial groups in alpine lakes. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Microbiology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Actinobacteria of the acI lineage are often the numerically dominant bacterial phylum in surface freshwaters, where they can account for > 50% of total bacteria. Despite their abundance, there are no described isolates. In an effort to obtain enrichment of these ubiquitous freshwater Actinobacteria, diluted freshwater samples from Lake Grosse Fuchskuhle, Germany, were incubated in 96-well culture plates. With this method, a successful enrichment containing high abundances of a member of the lineage acI was established. Phylogenetic classification showed that the acI Actinobacteria of the enrichment belonged to the acI- B2 tribe, which seems to prefer acidic lakes. This enrichment grows to low cell densities and thus the oligotrophic nature of acI- B2 was confirmed. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Microbiology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With this work we intend to stress the importance of considering discrete depth sampling for bacterial community analysis of stratified aquatic systems. Depth is a very important parameter to consider when sampling bacterial communities, as their abundance and composition can change within the distinct water layers. Stratified lakes are good model systems to study these connections since changes in environmental parameters can occur on a cm-scale at the thermo- and/or chemocline. Lake Grosse Fuchskuhle was sampled at discrete fine-scale depths at three time points covering a stage in which the lake was stratified and the beginning of winter mixing. In this paper we present the most abundant bacterial groups at the different depths sampled and also the most abundant operational taxonomic units ( OTUs). Overall, oxygen was found to be an important factor shaping the microbial community composition. [ABSTRACT FROM AUTHOR]

Actinobacteria within the acI lineage are often numerically dominating in freshwater ecosystems, where they can account for >50% of total bacteria in the surface water. However, they remain uncultured to date. We thus set out to use single-cell genomics to gain insights into their genetic make-up, with the aim of learning about their physiology and ecological niche. A representative from the highly abundant acI-B1 group was selected for shotgun genomic sequencing. We obtained a draft genomic sequence in 75 larger contigs (sum=1.16 Mb), with an unusually low genomic G+C mol% (∼42%). Actinobacteria core gene analysis suggests an almost complete genome recovery. We found that the acI-B1 cell had a small genome, with a rather low percentage of genes having no predicted functions (∼15%) as compared with other cultured and genome-sequenced microbial species. Our metabolic reconstruction hints at a facultative aerobe microorganism with many transporters and enzymes for pentoses utilization (for example, xylose). We also found an actinorhodopsin gene that may contribute to energy conservation under unfavorable conditions. This project reveals the metabolic potential of a member of the global abundant freshwater Actinobacteria. [ABSTRACT FROM AUTHOR]

The actinobacterial acI lineage is among the most successful and ubiquitous freshwater bacterioplankton found on all continents, often representing more than half of all microbial cells in the lacustrine environment and constituting multiple ecotypes. However, stably growing pure cultures of the acI lineage have not been established despite various cultivation efforts based on ecological and genomic studies on the lineage, which is in contrast to the ocean from which abundant microorganisms such as Prochlorococcus, Pelagibacter, and Nitrosopumilus have been isolated. Here, we report the first two pure cultures of the acI lineage successfully maintained by supplementing the growth media with catalase. Catalase was critical for stabilizing the growth of acI strains irrespective of the genomic presence of the catalase-peroxidase (katG) gene. The two strains, representing two novel species, displayed differential phenotypes and distinct preferences for reduced sulfurs and carbohydrates, some of which were difficult to predict based on genomic information. Our results suggest that culture of previously uncultured freshwater bacteria can be facilitated by a simple catalase-supplement method and indicate that genome-based metabolic prediction can be complemented by physiological analyses.

Dynamics of bacterial plankton community of eutrophic water reservoir in laboratory microecosystems with amino acid lysine was studied using PCR-DGGE technique. The addition of lysine to the microecosystems resulted in changes in the composition of the bacterial plankton in summer; in particular, a number of Lys1 and Lys2 species (genotypes) that consume this amino acid grew fast in the bacterial community. The plank tonic bacterial communities did not respond to the addition of lysine in spring and late summer. The obtained data confirm the hypothesis for the narrow specialization of bacterial plankton species to the consumption of individual organic substances. [ABSTRACT FROM AUTHOR]

Fluorescent in situ hybridization (FISH) with rRNA-specific oligonucleotide probes was used to assess the numbers and phylogenetic diversity of prokaryotic microorganisms in the water of small boreal lakes and peatland catchments of the swampy upper Volga basin. The abundance of bacterioplankton in lake water was found to vary from 1.6 to 8.7 × 10 cells ml, with the highest values detected in neutral eutrophic lakes. The total cell numbers in the peat of ombrotrophic bogs were 3.9-4.3 × 10 cells g of wet peat. The proportion of bacteria identified by the group-specific probes decreased from 79-85% in neutral (pH 6.6-6.9) mesotrophic and eutrophic lakes to 65-69% in acidic (pH 4.4-5.5) dystrophic lakes and to 51-58% in the peat of acidic (pH 3.6-3.9) ombrotrophic bogs. The diversity of bacterial communities was highest in lakes with neutral water. These communities were dominated by members of the phylum Actinobacteria (31-44% of the total bacterial number), while the contribution of Alphaproteobacteria (16-19%), Bacteroidetes (6-16%), Betaproteobacteria (6-7%), Planctomycetes (2-8%), and Gammaproteobacteria (4-5%) was also significant. In acidic dystrophic lakes, Actinobacteria (25-35%) and Betaproteobacteria (25-34%) predominated, while peatland catchments were dominated by the Alphaproteobacteria (20-23%). The presence of acidobacteria and some planctomycetes common for bogs in the water of acidic dystrophic lakes, as well as the high proportion of bacteria (31-49%) that were not identified by the group-specific probes, suggest the impact of microbial processes in peatland catchments on the microbial composition of the receiving waters. [ABSTRACT FROM AUTHOR]

In the well-known electromechanical analogy that converts between electrical and mechanical system representations, mass is the dual of a grounded capacitor. Consequently, any. electrical circuit that contains ungrounded capacitors, such as a filter, does not have a mechanical equivalent. A new mechanical system element representing a pulley-based differential transmission is proposed, which, when connected to a mass, is shown to simulate a capacitor in the general case. This new differential mass model provides an additional conceptual framework to model complex mechanical systems such as robotic manipulators. [ABSTRACT FROM AUTHOR]

The effect of branch scars on the initiation and occurrence of red heart in beech ( Fagus sylvatica L.) was studied on 17 trees with red heartwood and 14 trees with no discoloured heartwood, all of which were selected from a 120-year-old high-forest stand in Germany. Logistic regression was used to predict the probability of red heart occurrence for a given tree. The model was based on individual probabilities derived from geometric relationships between scar and knot morphologies, and integrated the diameter at breast height. Using this model, 27 of 31 trees were correctly classified, and the two groups of trees were clearly distinguished by probabilities below 0.25 and above 0.85 (with one exception). Given the constitution of the model, only 17 of 616 scars were found to initiate red heart formation, and the parameters of mechanistic variables were strongly correlated. The results suggest specifying the relationship between scars, knots and red heart, and extending the scope of the model. [ABSTRACT FROM AUTHOR]

A method for modeling the optomechanical coupling in MOEMS components is presented. For this purpose, the beam propagation method has been implemented using a hardware discription language. This enables the simulation of optical wave propagation on the system level, along with existing mechanical models in the same environment. Both free space and guided wave microopto-electromechanical systems components are simulated using this technique and satisfactory results are obtained [ABSTRACT FROM PUBLISHER]

Nitrification performance of a chemostat and a membrane-assisted bioreactor (MBR) was assessed at pilot scale for the treatment of sludge reject waters with NH4 +–N concentrations up to 600 mg/L and low organic content (COD<200 mg/L). To prevent nitrifier washout the 1-m3 MBR, τ was successively reduced to 6.2 h. Complete sludge retention was achieved by means of a 2-m3 MBR, τ was successively reduced to 6.2 h. Complete sludge retention was achieved by means of a 2-m2 100,000-Dalton PES ultrafiltration membrane. Operation in crossflow mode with flow velocities from v F×h). In the MBR, nitrification rates up to 2,500 g N/(m2×h). In the MBR, nitrification rates up to 2,500 g N/(m3×d) were measured with biomass concentrations between 4 and 15 g TSS/L. Despite low TSS values, about 0.2 g/L of the chemostat was able to nitrify 180 g N/(m3×d). The microbial community composition differed considerably between the two reactors as determined by fluorescent in situ hybridisation (FISH) with rRNA-targeted oligonucleotide probes. For both reactors, the relative abundance of ammonia and nitrite oxidisers measured by FISH was consistent with results from dynamic simulation of the nitrification process. [ABSTRACT FROM AUTHOR]

Five mixed samples prepared from the surface sediments of 20 north-east Mongolian soda lakes with total salt contents from 5 to 360 g/l and pH values from 9.7 to 10.5 were used to enrich for alkaliphilic ammonia-oxidizing bacteria. Successful enrichments at pH 10 were achieved on carbonate mineral medium containing 0.6 M total Na+ and ≤4 mM NH4Cl. Five isolates (ANs1–ANs5) of ammonia-oxidizing bacteria capable of growth at pH 10 were obtained from the colonies developed on bilayered gradient plates. The cells were motile and coccoid, with well-developed intracytoplasmic membranes (ICPM) and carboxysomes. At pH 10.0, ammonia was toxic for growth at concentrations higher than 5 mM NH4Cl. The bacteria were able to grow within the salinity range of 0.1–1.0 M of total Na+ (optimum 0.3 M). In media containing 0.3–0.6 M total Na+, optimal growth in batch cultures occurred in the presence of a bicarbonate/carbonate buffer system within the pH range 8.5–9.5, with the highest pH limit at pH 10.5. At pH lower than 8.0, growth was slower, most probably due to decreasing free ammonia. The pH profile of the respiratory activity was broader, with limits at 6.5–7.0 and 11.0 and an optimum at 9.5–10.0. In pH-controlled, NH3-limited continuous culture, isolate ANs5 grew up to pH 11.3, which is the highest pH limit known for ammonia-oxidizing bacteria so far. This showed the existence of extremely alkali-tolerant ammonia-oxidizing bacteria in the soda lakes. Comparative 16S rDNA sequence analysis of the five isolates demonstrated that they possess identical 16S rDNA genes and that they are closely related to Nitrosomonas halophila (sequence similarity 99.3%), a member of the β-subclass of the Proteobacteria. This affiliation was confirmed by comparative sequence analysis of the amoA gene, encoding the active-site subunit of the ammonia-monoxygenase, of one of the isolates. DNA-DNA hybridization data further supported that the soda lake isolates are very similar to each other and represent an alkali-tolerant subpopulation of N. halophila whose species description is herewith amended. [ABSTRACT FROM AUTHOR]

Presents an improved design of a silicon micromachined gyroscope or angular sensor. Comparison between the improved and previous gyroscope designs; Features and advantages of the design; Schematic diagram of the novel design; Closed-loop excitation of the prototype gyroscope.

Deals with a study which presented an application of analog hardware description languages for modeling optical and optoelectronic components and systems. Optronic devices and systems modeling; Information on point to point optical link; Information on the micro-optoelectro-mechanical systems modeling; Discussion on the modeling of wavelength division multiplexing optical communication network; Conclusion.

The article discusses the in situ hybridization with fluorescently labelled, rRNA- targeted nucleic acid probes in the study of microbial ecology. It is reported that the hybridization of environmental or clinical samples with rRNA-targeted nucleic acid probes is the best method to rapidly and accurately integrate new knowledge on the evolutionary relationships into studies of microbial ecology. The article stresses the benefits probes have for screening rRNA libraries for diversity, and the ease that in situ hybridization affords in identifying sequences directed by the environment.

Meromictic lakes are permanently stratified lakes that display steep gradients in salinity, oxygen and sulphur compounds tightly linked to bacterial community structure and diversity. Lake Sælenvannet is a meromictic lake located south of Bergen, Norway. The 26 m deep lake is connected to the open sea and permanently stratified into two layers separated by a chemocline. The upper water layer is brackish with major input from water runoff from the surroundings. The bottom layer consists of old saline water with low or no oxygen concentrations. Bacteria from phylum Planctomycetes are reported to be ubiquitous in lake environments. They are involved in the degradation of complex carbon sources in aquatic environments and are also linked to anaerobic processes such as fermentation and sulphur reduction. To study Planctomycete distribution along a chemical gradient, we sampled the water column throughout Lake Sælenvannet in 2012 and profiled the microbial community using 16S rRNA amplicon sequencing (metabarcoding) with 454 pyrosequencing. Planctomycetes related 16S rRNA gene sequences were found to be present both in the oxic and anoxic parts of the lake and showed an uneven distribution throughout the water column, with the highest relative abundance of 10% found in the saline anoxic layer at 15 m depth. In a follow-up study in 2014, samples from eight different depths were collected for enrichment and isolation of novel Planctomycetes. This study resulted in successful isolation in pure culture of 10 isolates affiliated to four different genera from the family Planctomycetaceae. One strain closely related to Blastopirellula cremea was isolated from 9 m depth, and two novel strains affiliated to the genera Stieleria and Gimesia were isolated at 7 and 9 m depths, respectively. Furthermore, seven isolates with identical 16S rRNA gene sequences were retrieved from seven different depths which varied greatly in salinity and chemical composition. These isolates likely represent a new species affiliated to Rubinisphaera. The adaptation of this novel Planctomycete to water depths spanning the entire chemical gradient could indicate a high phenotypic plasticity and/or a very efficient survival strategy. Overall, our results show the presence of a diverse group of Planctomycetes in Lake Sælenvannet, with a strong potential for novel adaptations to chemical stress factors. [ABSTRACT FROM AUTHOR]

The acI lineage of the phylum Actinobacteria is the most abundant bacterial group in most freshwater lakes. However, due to difficulties in laboratory cultivation, only two mixed cultures and some incomplete single-amplified or metagenome-derived genomes have been reported for the lineage. Here, we report the initial cultivation and complete genome sequences of four novel strains of the acI lineage from the tribes acI-A1, -A4, -A7, and -C1. The acI strains, initially isolated by dilution-to-extinction culturing, eventually failed to be maintained as axenic cultures. However, the first complete genomes of the acI lineage were successfully obtained from these initial cultures through whole genome amplification applied to more than hundreds of cultured acI cells. The genome sequences exhibited features of genome streamlining and showed that the strains are aerobic chemoheterotrophs sharing central metabolic pathways, with some differences among tribes that may underlie niche diversification within the acI lineage. Actinorhodopsin was found in all strains, but retinal biosynthesis was complete in only A1 and A4 tribes. [ABSTRACT FROM AUTHOR]