Studies on the Mechanism of the Volatile Oils from Caoguo-4 Decoction in Regulating Spleen Deficiency Diarrhea by Adjusting Intestinal Microbiota.

BACKGROUND: The Caoguo-4 decoction, a classical Mongolian medicine formula, is widely used to treat spleen deficiency diarrhea (SDD) in Mongolian for decades. Previously, the Caoguo-4 decoction volatile oil has been confirmed to be effective in ameliorating symptoms of spleen deficiency diarrhea in an animal model. However, the underlying mechanism of the Caoguo-4 decoction volatile oil is yet to be established. The aim of the current study was to investigate the antidiarrheal effects and mechanism of the Caoguo-4 decoction volatile oil. METHOD: Wistar rats were randomly divided into 5 groups of 10 animals including control, model, positive, Caoguo-4 decoction, and Caoguo-4 decoction volatile oil groups (10 rats in each group). All the rats, besides those in the control group, were induced to develop SDD by a bitter-cold purgation method with Xiaochengqi decoction. The antidiarrheal effect of Caoguo-4 decoction volatile oil was evaluated by pathological section, serum D-xylose and AMS content, plasma MTL content, and gut microbiota analysis via 16S rRNA sequencing. RESULTS: The results showed that the developed SDD rat model (model group) had decreased food intake, increased weight loss, soft stool, and bad hair color. When compared with the control group, serum was significantly reduced serum D-xylose and AML but increased MTL levels in the model group (p < 0.05). However, after treatment with either the Caoguo-4 decoction (the decoction group) or Smecta (the positive group) or volatile oil from the Caoguo-4 decoction (the volatile oil group), a significant increase in the serum D-xylose levels was observed. Additionally, AML levels significantly increased in the positive and volatile oil groups, and MTL levels significantly decreased in the decoction and volatile oil groups, when compared with the model group (p < 0.05). The pathological changes of the intestinal mucosa showed that the structure of the epithelium in the villi of the small intestine was affected, deformed, and incomplete in the model group when compared with the control group. However, either the decoction group or the volatile oil group recovered the villous morphology. The results of OTU analysis and alpha diversity analysis of intestinal bacteria showed that the intestinal microbiota of the SDD model rats showed an obvious decrease in richness and diversity of intestinal microbiota. But the intervention treatment of decoction and volatile oil could significantly recover the richness and diversity of intestinal microbiota. CONCLUSION: The intestinal microbiota destroyed in SDD modelling could be significantly improved by the Caoguo-4 decoction volatile oils, which provides reference for clinical medication.

Cyanobacterial Abundance and Microcystin Profiles in Two Southern British Lakes: The Importance of Abiotic and Biotic Interactions.

Freshwater cyanobacteria blooms represent a risk to ecological and human health through induction of anoxia and release of potent toxins; both conditions require water management to mitigate risks. Many cyanobacteria taxa may produce microcystins, a group of toxic cyclic heptapeptides. Understanding the relationships between the abiotic drivers of microcystins and their occurrence would assist in the implementation of targeted, cost-effective solutions to maintain safe drinking and recreational waters. Cyanobacteria and microcystins were measured by flow cytometry and liquid chromatography coupled to tandem mass spectrometry in two interconnected reservoirs varying in age and management regimes, in southern Britain over a 12-month period. Microcystins were detected in both reservoirs, with significantly higher concentrations in the southern lake (maximum concentration >7 µg L-1). Elevated microcystin concentrations were not positively correlated with numbers of cyanobacterial cells, but multiple linear regression analysis suggested temperature and dissolved oxygen explained a significant amount of the variability in microcystin across both reservoirs. The presence of a managed fishery in one lake was associated with decreased microcystin levels, suggestive of top down control on cyanobacterial populations. This study supports the need to develop inclusive, multifactor holistic water management strategies to control cyanobacterial risks in freshwater bodies.

Analysis of endophytic and rhizosphere bacterial diversity and function in the endangered plant Paeonia ludlowii.

Paeonia ludlowii is indigenous to Tibet and has an important ecological and economic value in China. In Tibet, P. ludlowii has been used in folk medicine with relative success. Plant microbial endophytes play an important role in plant growth, health and ecological function. The diversity of endophytic bacteria associated with P. ludlowii remains poorly understood. In this study, the structure of the endophytic bacterial communities associated with different tissues, including fruits, flowers, leaves, stems, and roots, and rhizosphere soils was analyzed with Illumina MiSeq sequencing of bacterial 16S rDNA. A total of 426,240 sequences and 4847 operational taxonomic units (OTUs) were obtained. The OTUs abundance of roots was higher than that of other tissues; however, the OTUs abundance was similar among different deep soil samples. In the plant tissues, Cyanobacteria was the most abundant bacterial phylum, followed by Proteobacteria; however, the most abundant phyla were Proteobacteria and Acidobacteria in soil samples from three different layers. In addition, the diversity and richness of the microorganisms in the soil were very similar to those in roots but higher than those in other tissues of P. ludlowii. Predictive metagenome analysis revealed that endophytic bacteria play critical functional roles in P. ludlowii. This conclusion could facilitate the study of the ecological functions of endophytic bacteria and their interactions with P. ludlowii to analyze the reasons why this important medicinal plant is becoming endangered.

Synthesis of Silver Nanoparticles Using a Novel Cyanobacteria Desertifilum sp. extract: Their Antibacterial and Cytotoxicity Effects.

BACKGROUND: The emergence of multi drug-resistant (MDR) bacterial infections and cancer has necessitated the development and discovery of alternative eco-safe antibacterial and anticancer agents. Biogenic fabrication of metallic nanoparticles is an emerging discipline for production of nanoproducts that exert potent anticancer and antibacterial activity, and do not suffer from the limitations inherent in physiochemical synthesis methods. METHODOLOGY: In this study, we isolated, purified, and characterized a novel cyanobacteria extract (Desertifilum IPPAS B-1220) to utilize in biofabrication of silver nanoparticles (D-SNPs). D-SNPs were produced by adding Desertifilum extract to silver nitrate solution under controlled conditions. Biofabrication of D-SNPs was confirmed using a UV-Vis spectrophotometer. The resultant D-SNPs were characterized using XRD, FTIR, SEM, and TEM. The toxicity of D-SNPs against five pathogenic bacteria and three cancer cell lines (MCF-7, HepG2, and Caco-2) was evaluated. RESULTS: Formation of D-SNPs was indicated by a color change from pale yellow to dark brown. The peak of the surface plasmon resonance of the D-SNPs was at 421 nm. The XRD detected the crystallinity of D-SNPs. FTIR showed that polysaccharides and proteins may have contributed to the biofabrication of D-SNPs. Under SEM and TEM, the D-SNPs were spherical with diameter ranges from 4.5 to 26 nm. The D-SNPs significantly suppressed the growth of five pathogenic bacteria, and exerted cytotoxic effects against MCF-7, HepG2, and Caco-2 cancer cells with IC50 values of 58, 32, and 90 µg/mL, respectively. CONCLUSION: These findings showed for the first time the potentiality of novel cyanobacteria strain Desertifilum IPPAS B-1220 to fabricate small SNPs that acted as potent anticancer and antibacterial material against different cancer cell lines and pathogenic bacterial strains. These findings encourage the researchers to focus on cyanobacteria in general and especially Desertifilum sp. IPPAS B-1220 for synthesizing different NPs that opening the window for new applications.

Effects of 308 nm excimer light treatment on the skin microbiome of atopic dermatitis patients.

BACKGROUND: The skin microbiome has been implicated in the pathophysiology of atopic dermatitis (AD). Although 308 nm excimer light treatment is an effective phototherapy for AD, its effects on the skin microbiome currently remain unclear. Therefore, we investigated the effects of the excimer light treatment on the skin bacterial and fungal microbiome of lesional skin of AD. METHODS: Swab samples were collected from 11 healthy controls, non-lesional and lesional skin of 11 AD patients. The excimer light treatment was administered to the lesional skin. The composition of the skin microbiome, the clinical score and skin barrier function of the lesional skin were examined before and after the treatment. The composition of the skin microbiome was determined by sequencing bacterial 16S and fungal internal transcribed spacer regions. RESULTS: The excimer light treatment significantly changed the composition of the bacterial microbiome in the lesional skin of AD, as well as improved the clinical score and skin barrier function. The treatment increased the relative abundance of the phylum Cyanobacteria and decreased that of the phylum Bacteroidetes in lesional skin. At the species level, the treatment significantly decreased the relative abundance of Staphylococcus aureus (S aureus) in lesional skin. There was also a significant correlation between the reduction of S aureus and improvement of the clinical outcomes. CONCLUSION: Our findings suggest that alterations of the skin microbiome with excimer light treatment, specifically the decrease in the abundance of S aureus, are partly involved in the improvement of AD lesions.

Impacts of microbial assemblage and environmental conditions on the distribution of anatoxin-a producing cyanobacteria within a river network.

Blooms of planktonic cyanobacteria have long been of concern in lakes, but more recently, harmful impacts of riverine benthic cyanobacterial mats been recognized. As yet, we know little about how various benthic cyanobacteria are distributed in river networks, or how environmental conditions or other associated microbes in their consortia affect their biosynthetic capacities. We performed metagenomic sequencing for 22 Oscillatoriales-dominated (Cyanobacteria) microbial mats collected across the Eel River network in Northern California and investigated factors associated with anatoxin-a producing cyanobacteria. All microbial communities were dominated by one or two cyanobacterial species, so the key mat metabolisms involve oxygenic photosynthesis and carbon oxidation. Only a few metabolisms fueled the growth of the mat communities, with little evidence for anaerobic metabolic pathways. We genomically defined four cyanobacterial species, all which shared <96% average nucleotide identity with reference Oscillatoriales genomes and are potentially novel species in the genus Microcoleus. One of the Microcoleus species contained the anatoxin-a biosynthesis genes, and we describe the first anatoxin-a gene cluster from the Microcoleus clade within Oscillatoriales. Occurrence of these four Microcoleus species in the watershed was correlated with total dissolved nitrogen and phosphorus concentrations, and the species that contains the anatoxin-a gene cluster was found in sites with higher nitrogen concentrations. Microbial assemblages in mat samples with the anatoxin-a gene cluster consistently had a lower abundance of Burkholderiales (Betaproteobacteria) species than did mats without the anatoxin-producing genes. The associations of water nutrient concentrations and certain co-occurring microbes with anatoxin-a producing Microcoleus motivate further exploration for their roles as potential controls on the distributions of toxigenic benthic cyanobacteria in river networks.

Cyanobacterial removal by a red soil-based flocculant and its effect on zooplankton: an experiment with deep enclosures in a tropical reservoir in China.

As one kind of cheap, environmentally-friendly and efficient treatment materials for direct control of cyanobacterial blooms, modified clays have been widely concerned. The present study evaluated cyanobaterial removal by a red soil-based flocculant (RSBF) with a large enclosure experiment in a tropical mesotrophic reservoir, in which phytoplankton community was dominated by Microcystis spp. and Anabaena spp. The flocculant was composed of red soil, chitosan and FeCl3. Twelve enclosures were used in the experiment: three replicates for each of one control and three treatments RSBF15 (15 mg FeCl3 l-1), RSBF25 (25 mg FeCl3 l-1), and RSBF35 (35 mg FeCl3 l-1). The results showed that the red soil-based flocculant can significantly remove cyanobacterial biomass and reduce concentrations of nutrients including total nitrogen, nitrate, ammonia, total phosphorus, and orthophosphate. Biomass of Microcystis spp. and Anabaena spp. was reduced more efficiently (95%) than other filamentous cyanobacteria (50%). In the RSBF15 treatment, phytoplankton biomass recovered to the level of the control group after 12 days and cyanobacteria quickly dominated. Phytoplankton biomass in the RSBF25 treatment also recovered after 12 days, but green algae co-dominated with cyanobacteria. A much later recovery of phytoplankton until the day of 28 was observed under RSBF35 treatment, and cyanobacteria did no longer dominate the phytoplankton community. The application of red soil-based flocculant greatly reduces zooplankton, especially rotifers, however, Copepods and Cladocera recovered fast. Generally, the red soil-based flocculant can be effective for urgent treatments at local scales in cyanobacteria dominating systems.

Using generalized additive models to investigate factors influencing cyanobacterial abundance through phycocyanin fluorescence in East Lake, China.

East Lake is a shallow lake (in Wuhan, China) where cyanobacteria blooms occurred frequently from 1970 to 1985. During the study period, all Carlson trophic state index values were > 50, indicating that East Lake is in a eutrophic state. In this study, phycocyanin concentrations were measured through phycocyanin fluorometry for rapid assessment of cyanobacterial abundance. The smoothing splines of the optimal generalized additive model (GAM) indicated that Secchi depth (SD), total phosphorus (TP) and dissolved oxygen (DO) concentrations, electrical conductivity (EC), chemical oxygen demand (COD), and ratios of total nitrogen (TN) to TP (TN:TP) were the main environmental factors in a moderate nonlinear relationship with cyanobacterial phycocyanin concentrations in East Lake. The shape of the GAM smoother can be used to quantify the relationship between a response variable and an explanatory variable in the scatterplot. Phycocyanin concentrations were sharply and negatively related to both SD and EC when the SD was 20-80 cm and EC was > 270 mg/L. Phycocyanin concentrations increased with concentrations of TP, DO, and COD. Phycocyanin concentrations increased sharply with TP concentrations when TP concentrations were > 0.10 mg/L and approached to a constant when DO concentrations were > 8.20 mg/L. Approximately, 85% of the phycocyanin concentrations were negatively correlated with TN:TP of < 26. In summary, organic compounds and TP were inferred to the key factors limiting the potential growth of cyanobacteria in East Lake. These change points/thresholds of smoothing splines of aforementioned variables may serve as a framework for managing the cyanobacterial growth.

Microbial community changes during a toxic cyanobacterial bloom in an alkaline Hungarian lake.

The Carpathian Basin is a lowland plain located mainly in Hungary. Due to the nature of the bedrock, alluvial deposits, and a bowl shape, many lakes and ponds of the area are characterized by high alkalinity. In this study, we characterized temporal changes in eukaryal and bacterial community dynamics with high throughput sequencing and relate the changes to environmental conditions in Lake Velence located in Fejér county, Hungary. The sampled Lake Velence microbial populations (algal and bacterial) were analyzed to identify potential correlations with other community members and environmental parameters at six timepoints over 6 weeks in the Spring of 2012. Correlations between community members suggest a positive relationship between certain algal and bacterial populations (e.g. Chlamydomondaceae with Actinobacteria and Acidobacteria), while other correlations allude to changes in these relationships over time. During the study, high nitrogen availability may have favored non-nitrogen fixing cyanobacteria, such as the toxin-producing Microcystis aeruginosa, and the eutrophic effect may have been exacerbated by high phosphorus availability as well as the high calcium and magnesium content of the Carpathian Basin bedrock, potentially fostering exopolymer production and cell aggregation. Cyanobacterial bloom formation could have a negative environmental impact on other community members and potentially affect overall water quality as well as recreational activities. To our knowledge, this is the first prediction for relationships between photoautotrophic eukaryotes and bacteria from an alkaline, Hungarian lake.

Hepatotoxicity induced by paclitaxel interaction with turmeric in association with a microcystin from a contaminated dietary supplement.

A 67-year-old Caucasian male with lung cancer was presented to the Emergency Department with asthenia, anorexia, jaundice and choluria. The patient's lung cancer was being treated medically by a combination of paclitaxel/carboplatin with bi-monthly frequency. The patient was also self-medicating with several natural products, including Chlorella (520 mg/day), Silybum marianum (total of 13.5 mg silymarin/day), zinc sulphate (5.5 mg), selenium (50 µg) and 15 g/day of Curcuma longa. In first chemotherapy cycle no toxicity was observed even he was taking other medications as budesonide and sitagliptin. The toxic events started only after the introduction of the dietary products. Chlorella had contamination with cyanobacteria (Oscillatoriales) and 1.08 µg of cyanotoxin Microcystin-LR (MC-LR) per gram of biomass was found. Patient was consuming ca 0.01 µg MC-LR/kg/day. This case report describes the first known case of paclitaxel toxicity probably related to pharmacokinetic interaction with Turmeric and a contaminated Chlorella supplement resulting in an acute toxic hepatitis and the impact on oncologic patient health.

Bacterial communities of four adjacent fresh lakes at different trophic status.

Knowing the microbial compositions in fresh lakes is significant to explore the mechanisms of eutrophication and algal blooms. This study reported on the bacterial communities of the four adjacent fresh lakes at different trophic status by Illumina MiSeq Platform, which were Tangxun Lake (J1), Qingling Lake (J2), Huangjia Lake (J3) and Niushan Lake (J4) in Wuhan, China. J1 had the highest salinity and phosphorus. J2 was abundant in TC (Total Carbon)/TOC (Total Organic Carbon.), calcium and magnesium. J3 had the highest content of nitrogen, iron and pollution of heavy metals. High-throughput sequencing analysis of the 16S rRNA gene revealed that the eutrophic lakes (J1, J2 and J3) were dominated by Cyanobacteria (46.1% for J1, 40.8% for J2, 33.4% for J3) and the oligotrophic lake (J4) was dominated by Actinobacteria (34.2%). An increase of Cyanobacteria could inhibit the growth of Proteobacteria, Actinobacteria and Bacteroidetes. Functional inferences from 16S rRNA sequences suggested that J4 had more abundant bacteria with regard to substrate metabolism than J1, J2, and J3. Burkholderia and Fluviicola might be a suggestion of good water quality. The results demonstrated that the bacterial community could well reflect the water quality of the four lakes.

Critical Assessment of Analytical Techniques in the Search for Biomarkers on Mars: A Mummified Microbial Mat from Antarctica as a Best-Case Scenario.

The search for biomarkers of present or past life is one of the major challenges for in situ planetary exploration. Multiple constraints limit the performance and sensitivity of remote in situ instrumentation. In addition, the structure, chemical, and mineralogical composition of the sample may complicate the analysis and interpretation of the results. The aim of this work is to highlight the main constraints, performance, and complementarity of several techniques that have already been implemented or are planned to be implemented on Mars for detection of organic and molecular biomarkers on a best-case sample scenario. We analyzed a 1000-year-old desiccated and mummified microbial mat from Antarctica by Raman and IR (infrared) spectroscopies (near- and mid-IR), thermogravimetry (TG), differential thermal analysis, mass spectrometry (MS), and immunological detection with a life detector chip. In spite of the high organic content (ca. 20% wt/wt) of the sample, the Raman spectra only showed the characteristic spectral peaks of the remaining beta-carotene biomarker and faint peaks of phyllosilicates over a strong fluorescence background. IR spectra complemented the mineralogical information from Raman spectra and showed the main molecular vibrations of the humic acid functional groups. The TG-MS system showed the release of several volatile compounds attributed to biopolymers. An antibody microarray for detecting cyanobacteria (CYANOCHIP) detected biomarkers from Chroococcales, Nostocales, and Oscillatoriales orders. The results highlight limitations of each technique and suggest the necessity of complementary approaches in the search for biomarkers because some analytical techniques might be impaired by sample composition, presentation, or processing. Key Words: Planetary exploration-Life detection-Microbial mat-Life detector chip-Thermogravimetry-Raman spectroscopy-NIR-DRIFTS. Astrobiology 17, 984-996.

The rise of algae in Cryogenian oceans and the emergence of animals.

The transition from dominant bacterial to eukaryotic marine primary productivity was one of the most profound ecological revolutions in the Earth's history, reorganizing the distribution of carbon and nutrients in the water column and increasing energy flow to higher trophic levels. But the causes and geological timing of this transition, as well as possible links with rising atmospheric oxygen levels and the evolution of animals, remain obscure. Here we present a molecular fossil record of eukaryotic steroids demonstrating that bacteria were the only notable primary producers in the oceans before the Cryogenian period (720-635 million years ago). Increasing steroid diversity and abundance marks the rapid rise of marine planktonic algae (Archaeplastida) in the narrow time interval between the Sturtian and Marinoan 'snowball Earth' glaciations, 659-645 million years ago. We propose that the incumbency of cyanobacteria was broken by a surge of nutrients supplied by the Sturtian deglaciation. The 'Rise of Algae' created food webs with more efficient nutrient and energy transfers, driving ecosystems towards larger and increasingly complex organisms. This effect is recorded by the concomitant appearance of biomarkers for sponges and predatory rhizarians, and the subsequent radiation of eumetazoans in the Ediacaran period.

Nutrient treatments alter microbial mat colonization in two glacial meltwater streams from the McMurdo Dry Valleys, Antarctica.

Microbial mats are abundant in many alpine and polar aquatic ecosystems. With warmer temperatures, new hydrologic pathways are developing in these regions and increasing dissolved nutrient fluxes. In the McMurdo Dry Valleys, thermokarsting may release both nutrients and sediment, and has the potential to influence mats in glacial meltwater streams. To test the role of nutrient inputs on community structure, we created nutrient diffusing substrata (NDS) with agar enriched in N, P and N + P, with controls, and deployed them into two Dry Valley streams. We found N amendments (N and N + P) to have greater chlorophyll-a concentrations, total algal biovolume, more fine filamentous cyanobacteria and a higher proportion of live diatoms than other treatments. Furthermore, N treatments were substantially elevated in Bacteroidetes and the small diatom, Fistulifera pelliculosa. On the other hand, species richness was almost double in P and N + P treatments over others, and coccoid green algae and Proteobacteria were more abundant in both streams. Collectively, these data suggest that nutrients have the potential to stimulate growth and alter community structure in glacial meltwater stream microbial mats, and the recent erosion of permafrost and accelerated glacial melt will likely impact resident biota in polar lotic systems here and elsewhere.

Preliminary Assessment of Cyanobacteria Diversity and Toxic Potential in Ten Freshwater Lakes in Selangor, Malaysia.

Toxic cyanobacteria blooms are increasing in magnitude and frequency worldwide. However, this issue has not been adequately addressed in Malaysia. Therefore, this study aims to better understand eutrophication levels, cyanobacteria diversity, and microcystin concentrations in ten Malaysian freshwater lakes. The results revealed that most lakes were eutrophic, with total phosphorus and total chlorophyll-a concentrations ranging from 15 to 4270 µg L(-1) and 1.1 to 903.1 µg L(-1), respectively. Cyanobacteria were detected in all lakes, and identified as Microcystis spp., Planktothrix spp., Phormidium spp., Oscillatoria spp., and Lyngbya spp. Microcystis spp. was the most commonly observed and most abundant cyanobacteria recorded. Semi-quantitative microcystin analysis indicated the presence of microcystin in all lakes. These findings illustrate the potential health risk of cyanobacteria in Malaysia freshwater lakes, thus magnifying the importance of cyanobacteria monitoring and management in Malaysian waterways.

Microbial diversity in Paris polyphylla var. yunnanensis rhizomes of varying ages.

Endophyte microorganisms live inside plants without causing them any apparent damage. Recently, endophytic microorganisms have attracted attention because they can produce bioactive compounds of biotechnological interest. The endophytic microorganisms in Paris polyphylla var. yunnanensis (Liliaceae) - a species used since antiquity in traditional Chinese medicine - are under scrutiny because they may be responsible for producing the bioactive metabolites associated with the plant. The levels of bioactive metabolites in the rhizomes of P. polyphylla increase with rhizome age. To elucidate the roles played by endophytes in the accumulation of bioactive metabolites, we investigated the community structure and diversity of the endophytic microorganisms in P. polyphylla rhizomes of different ages (4, 6, and 8 years) using 16S rRNA and internal transcribed spacer (ITS) sequence analysis. 16S rDNA amplicon pyrosequencing revealed that the number of operational taxonomic units was lower in the 8-year-old samples than in the other samples. A total of 28 phyla were observed in the P. polyphylla samples and the predominant bacteria were of the Cyanobacteria and Proteobacteria phyla. Moreover, the percentage of Cyanobacteria increased with rhizome age. Similarly, ITS1 amplicon pyrosequencing identified developmental changes in the most abundant fungal classes; some classes were more prevalent in the 8-year-old rhizomes than in younger rhizomes, indicating the importance in secondary metabolism in older rhizomes. Our study showed that endophyte microorganism diversity and prevalence depend on P. polyphylla rhizome age. There was also an indication that some endophyte microorganisms contribute to the higher saponin content in older P. polyphylla specimens.

Eutrophic urban ponds suffer from cyanobacterial blooms: Dutch examples.

Ponds play an important role in urban areas. However, cyanobacterial blooms counteract the societal need for a good water quality and pose serious health risks for citizens and pets. To provide insight into the extent and possible causes of cyanobacterial problems in urban ponds, we conducted a survey on cyanobacterial blooms and studied three ponds in detail. Among 3,500 urban ponds in the urbanized Dutch province of North Brabant, 125 showed cyanobacterial blooms in the period 2009-2012. This covered 79% of all locations registered for cyanobacterial blooms, despite the fact that urban ponds comprise only 11% of the area of surface water in North Brabant. Dominant bloom-forming genera in urban ponds were Microcystis, Anabaena and Planktothrix. In the three ponds selected for further study, the microcystin concentration of the water peaked at 77 µg l(-1) and in scums at 64,000 µg l(-1), which is considered highly toxic. Microcystin-RR and microcystin-LR were the most prevalent variants in these waters and in scums. Cyanobacterial chlorophyll-a peaked in August with concentrations up to 962 µg l(-1) outside of scums. The ponds were highly eutrophic with mean total phosphorus concentrations between 0.16 and 0.44 mg l(-1), and the sediments were rich in potential releasable phosphorus. High fish stocks dominated by carp lead to bioturbation, which also favours blooms. As urban ponds in North Brabant, and likely in other regions, regularly suffer from cyanobacterial blooms and citizens may easily have contact with the water and may ingest cyanobacterial material during recreational activities, particularly swimming, control of health risk is of importance. Monitoring of cyanobacteria and cyanobacterial toxins in urban ponds is a first step to control health risks. Mitigation strategies should focus on external sources of eutrophication and consider the effect of sediment P release and bioturbation by fish.

Nutrient sequestration, biomass production by microalgae and phytoremediation of sewage water.

The present work was aimed at analysing the role of inoculated microalgae in nutrient dynamics, bioremediation and biomass production of sewage water. Preliminary microscopic analyses of sewage water revealed the presence of different algal groups, with predominance of Cyanophyta. Among the inoculated strains, Calothrix showed highest dry cell weight (916.67 mg L(-1)), chlorophyll and carotenoid content in tap water + sewage water (1:1) treatment. Significant removal of NO3-N ranging from 57-78% and PO4-P (44-91%) was recorded in microalgae inoculated tap water + sewage water. The total dissolved solids and electrical conductivity of tap water + sewage water after incubation with Calothrix sp. decreased by 28.5 and 28.0%, accompanied by an increase in dissolved oxygen from 4.4 to 6.4 mg L(-1) on the 20th day. Our investigation revealed the robustness of Calothrix sp. in sequestering nutrients (N and P), improving water quality and proliferating in sewage water.

Phytoplankton and bacterioplankton abundances and community dynamics in Lake Erhai.

The composition and seasonal variation of the phytoplankton and bacterioplankton community were investigated, and SPSS and redundancy analysis (RDA) were used to explore the relationship between the phytoplankton and bacterioplankton community dynamics in the typical plateau Lake of Lake Erhai from July 2009 to April 2010. Obvious seasonal variation of phytoplankton was observed, and the abundance of phytoplankton ranged from 2.02 × 10(6) to 57.9 × 10(6) cells/L. The dominant species in autumn and summer was Microcystis sp., Psephonema aenigmaticum Skuja was dominant in winter, and Microcystis sp., Aphanizonmenon flos-aquae, Asterionella sp., P. aenigmaticum, etc. were dominant in spring. The abundance of bacterioplankton in the whole lake changed between 1.93 × 10(9) and 4.61 × 10(9) cells/L showing distinct seasonal variation characteristics. The results of correlation and RDA indicated that the abundance and community diversity of bacterioplankton were significantly correlated with the abundance of phytoplankton, and the group of Bacteroidetes had obvious correlation with Microcystis sp. and other cyanobacteria, which might have some links with the harmful algal blooms in Lake Erhai. Further research is needed to study the mechanisms of interactions between phytoplankton and bacterioplankton communities.

Subsurface associations of Acaryochloris-related picocyanobacteria with oil-utilizing bacteria in the Arabian Gulf water body: promising consortia in oil sediment bioremediation.

Two picocyanobacterial strains related to Acaryochloris were isolated from the Arabian Gulf, 3 m below the water surface, one from the north shore and the other from the south shore of Kuwait. Both strains were morphologically, ultrastructurally, and albeit to a less extend, phylogenetically similar to Acaryochloris. However, both isolates lacked chlorophyll d and produced instead chlorophyll a, as the major photosynthetic pigment. Both picocyanobacterial isolates were associated with oil-utilizing bacteria in the magnitude of 10(5) cells g(-1). According to their 16S rRNA gene sequences, bacteria associated with the isolate from the north were affiliated to Paenibacillus sp., Bacillus pumilus, and Marinobacter aquaeolei, but those associated with the isolate from the south were affiliated to Bacillus asahii and Alcanivorax jadensis. These bacterial differences were probably due to environmental variations. In batch cultures, the bacterial consortia in the nonaxenic biomass as well as the pure bacterial isolates effectively consumed crude oil and pure aliphatic and aromatic hydrocarbons, including very high-molecular-weight compounds. Water and diethylether extracts from the phototrophic biomass enhanced growth of individual bacterial isolates and their hydrocarbon-consumption potential in batch cultures. It was concluded that these consortia could be promising in bioremediation of hydrocarbon pollutants, especially heavy sediments in the marine ecosystem.