Nitrogen and phosphorus significantly alter growth, nitrogen fixation, anatoxin-a content, and the transcriptome of the bloom-forming cyanobacterium, .

While freshwater cyanobacteria are traditionally thought to be limited by the availability of phosphorus (P), fixed nitrogen (N) supply can promote the growth and/or toxin production of some genera. This study characterizes how growth on N (control), nitrate (NO ), ammonium (NH ), and urea as well as P limitation altered the growth, toxin production, N fixation, and gene expression of an anatoxin-a (ATX-A) - producing strain of sp. 54.

Dynamic Responses of Endosymbiotic Microbial Communities Within Colonies in North American Lakes to Altered Nitrogen, Phosphorus, and Temperature Levels.

The toxic cyanobacterium, , is a pervasive cyanobacterial harmful algal bloom (CHAB) - forming genus that naturally occurs in colonies that harbor diverse microbiomes of heterotrophic bacteria. While the effects of nutrient loading and climatic warming on CHABs are well-known, little is known regarding how these environmental drivers alter the structural and functional potential of the microbial assemblages associated with blooms that, in turn, may impact cyanobacterial growth. Here, we used next-generation sequencing of 16S ribosomal rRNA genes to characterize the dynamics of the bacterial assemblages within colonies in two temperate North American lakes: Lake Erie and Lake Agawam (NY, United States) and quantified their responses to experimentally increased levels of nitrogen (N), phosphorus (P) and temperature.

Novel high throughput sequencing - fluorometric approach demonstrates Microcystis blooms across western Lake Erie are promoted by grazing resistance and nutrient enhanced growth.

Cyanobacterial harmful algal blooms (CHABs) are a global public health threat. While CHABs are often promoted by nutrients, an important and often overlooked influence on bloom dynamics is zooplankton grazing. In the present study, zooplankton grazing and nutrient enrichment experiments were combined with next generation sequencing and fluorometric analyses to quantify differential grazing and nutrient effects on specific cyanobacterial genera across the western basin of Lake Erie.

The Composition and Function of Microbiomes Within Colonies Are Significantly Different Than Native Bacterial Assemblages in Two North American Lakes.

The toxic cyanobacterium is one of the most pervasive harmful algal bloom (HAB) genera and naturally occurs in large colonies known to harbor diverse heterotrophic bacterial assemblages. While colony-associated microbiomes may influence blooms, there remains a limited understanding of the structure and functional potential of these communities and how they may be shaped by changing environmental conditions. To address this gap, we compared the dynamics of -attached (MCA), free-living (FL), and whole water (W) microbiomes during blooms using next-generation amplicon sequencing (16S rRNA), a predictive metagenome software, and other bioinformatic approaches.

The Individual and Combined Effects of the Cyanotoxins, Anatoxin-a and Microcystin-LR, on the Growth, Toxin Production, and Nitrogen Fixation of Prokaryotic and Eukaryotic Algae.

Globally, eutrophication and warming of aquatic ecosystems has increased the frequency and intensity of cyanobacterial blooms and their associated toxins, with the simultaneous detection of multiple cyanotoxins often occurring. Despite the co-occurrence of cyanotoxins such as microcystins and anatoxin-a (ATX) in water bodies, their effects on phytoplankton communities are poorly understood. The individual and combined effects of microcystin-LR (MC-LR) and ATX on the cyanobacteria spp.

Succession and toxicity of Microcystis and Anabaena (Dolichospermum) blooms are controlled by nutrient-dependent allelopathic interactions.

Microcystis and Anabaena (Dolichospermum) are among the most toxic cyanobacterial genera and often succeed each other during harmful algal blooms. The role allelopathy plays in the succession of these genera is not fully understood. The allelopathic interactions of six strains of Microcystis and Anabaena under different nutrient conditions in co-culture and in culture-filtrate experiments were investigated.

Effects of Microcystis on development of early life stage Japanese medaka (Oryzias latipes): Comparative toxicity of natural blooms, cultured Microcystis and microcystin-LR.

Freshwater cyanobacterial harmful algal blooms (CyanoHABs) caused by algae in the genus Microcystis have been increasing in frequency and severity in recent decades. Microcystis blooms threaten aquatic organisms through effects associated with the rapid increase of biomass and the production of the hepatotoxin microcystin (MC) by toxic strains. Among fish, effects of blooms are likely to be more severe for early life stages, and physiological impacts on this life stage could significantly impact recruitment and fish populations.

Transcriptomic Responses in the Bloom-Forming Cyanobacterium Microcystis Induced during Exposure to Zooplankton.

The bloom-forming, toxic cyanobacterium synthesizes multiple secondary metabolites and has been shown to deter zooplankton grazing. However, the biochemical and/or molecular basis by which deters zooplankton remains unclear. This global transcriptomic study explored the response of to direct and indirect exposures to multiple densities of two cladoceran grazers, and Higher densities of both daphnids significantly reduced cell densities and elicited a stronger transcriptional response in While many putative grazer deterrence genes (encoding microcystin, aeruginosin, cyanopeptolin, and microviridin) were largely unaffected by zooplankton, transcripts for heat shock proteins () increased in abundance.

Quantitative Trait Loci for Yield and Yield-Related Traits in Spring Barley Populations Derived from Crosses between European and Syrian Cultivars.

In response to climatic changes, breeding programmes should be aimed at creating new cultivars with improved resistance to water scarcity. The objective of this study was to examine the yield potential of barley recombinant inbred lines (RILs) derived from three cross-combinations of European and Syrian spring cultivars, and to identify quantitative trait loci (QTLs) for yield-related traits in these populations. RILs were evaluated in field experiments over a period of three years (2011 to 2013) and genotyped with simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers; a genetic map for each population was constructed and then one consensus map was developed.

Diversifying selection by Desmodiinae legume species on Bradyrhizobium symbionts.

Desmodium and Hylodesmum (Papilionoideae Subtribe Desmodiinae) are among the most common herbaceous perennial legumes native to eastern North America. To analyze the population structure of their Bradyrhizobium sp. root-nodule bacteria, 159 isolates were sampled from ten host species across a 1000 km region.

Ecological aspects of transformation in Poland's agriculture based on the Wielkopolska Region.

Transformation in Polish agriculture initiated by political changes in the 1990s brought about essential variations in the structure of agricultural land use. The share of cereals in cropping patterns increased, while fodder plants decreased. In addition, the level of mineral fertilization was reduced.