Microalgae cultivation using ammonia and carbon dioxide concentrations typical of pig barns.

While global population growth drives increased production efficiency in animal agriculture, there is a growing demand for environmentally friendly practices, particularly in reducing air pollutant emissions from concentrated animal feeding operations. This study explores the potential of cultivating microalgae in photobioreactors (PBRs) as an eco-friendly and cost-effective approach to mitigate NH3 and CO2 emissions from pig barns. Unlike traditional physicochemical mitigation systems, microalgae offer a renewable solution by converting pollutants into valuable biomass. The research focused on Scenedesmus dimorphus growth under typical NH3 and CO2 concentrations found in the indoor air of pig barns. Four NH3 (0, 12, 25, and 50 ppm) and four CO2 concentrations (350, 1200, 2350, and 3500 ppm) were tested using photobioreactors. Results showed a maximum specific growth rate of 0.83 d-1 with 12 ppm NH3 and 3500 ppm CO2. The dry biomass concentration was significantly higher (1.16 ± 0.08 g L-1; p < 0.01) at 25 ppm NH3 and 2350 ppm CO2 than other test conditions. S. dimorphus demonstrated the peak NH3 and CO2 fixation rates (23.8 ± 2.26 mg NH3 L-1 d-1 and 432.24 ± 41.09 mg CO2 L-1 d-1) at 25 ppm NH3 and 2350 ppm CO2. These findings support the feasibility of using algae to effectively remove air pollutants in pig barns, thereby improving indoor air quality.

Algae and Their Metabolites as Potential Bio-Pesticides.

An increasing human population necessitates more food production, yet current techniques in agriculture, such as chemical pesticide use, have negative impacts on the ecosystems and strong public opposition. Alternatives to synthetic pesticides should be safe for humans, the environment, and be sustainable. Extremely diverse ecological niches and millions of years of competition have shaped the genomes of algae to produce a myriad of substances that may serve humans in various biotechnological areas. Among the thousands of described algal species, only a small number have been investigated for valuable metabolites, yet these revealed the potential of algal metabolites as bio-pesticides. This review focuses on macroalgae and microalgae (including cyanobacteria) and their extracts or purified compounds, that have proven to be effective antibacterial, antiviral, antifungal, nematocides, insecticides, herbicides, and plant growth stimulants. Moreover, the mechanisms of action of the majority of these metabolites against plant pests are thoroughly discussed. The available information demonstrated herbicidal activities via inhibition of photosynthesis, antimicrobial activities via induction of plant defense responses, inhibition of quorum sensing and blocking virus entry, and insecticidal activities via neurotoxicity. The discovery of antimetabolites also seems to hold great potential as one recent example showed antimicrobial and herbicidal properties. Algae, especially microalgae, represent a vast untapped resource for discovering novel and safe biopesticide compounds.

Status and Prospects of Botanical Biopesticides in Europe and Mediterranean Countries.

Concerning human and environmental health, safe alternatives to synthetic pesticides are urgently needed. Many of the currently used synthetic pesticides are not authorized for application in organic agriculture. In addition, the developed resistances of various pests against classical pesticides necessitate the urgent demand for efficient and safe products with novel modes of action. Botanical pesticides are assumed to be effective against various crop pests, and they are easily biodegradable and available in high quantities and at a reasonable cost. Many of them may act by diverse yet unexplored mechanisms of action. It is therefore surprising that only few plant species have been developed for commercial usage as biopesticides. This article reviews the status of botanical pesticides, especially in Europe and Mediterranean countries, deepening their active principles and mechanisms of action. Moreover, some constraints and challenges in the development of novel biopesticides are highlighted.

Comprehensive multi-technique approach reveals the high diversity of microcystins in field collections and an associated isolate of Microcystis aeruginosa from a Turkish lake.

Microcystins (MCs) are hepatotoxic and potentially carcinogenic cyanotoxins. They exhibit high structural variability, with nearly 250 variants described to date. This variability can result in incomplete detection of MC variants during lake surveys due to the frequent use of targeted analytical methods and a lack of standards available for identification and quantitation. In this study, Lake Uluabat in Turkey was sampled during the summer of 2015. Phylogenetic analysis of the environmental mcyA sequences suggested Microcystis spp. were the major MC contributors. A combination of liquid chromatography-tandem mass spectrometry (LC-MS/MS), liquid chromatography with UV detection and mass spectrometry (LC-UV-MS), and a novel liquid chromatography-high resolution mass spectrometry (LC-HRMS) method, together with thiol and periodate reactivity, revealed more than 36 MC variants in the lake samples and a strain of M. aeruginosa (AQUAMEB-24) isolated from Lake Uluabat. Only MCs containing arginine at position-4 were detected in the culture, while MC-LA, -LY, -LW and -LF were also detected in the lake samples, suggesting the presence of other MC producers in the lake. The previously unreported MCs MC-(H2)YR (dihydrotyrosine at position-2) (17), [epoxyAdda5]MC-LR, [DMAdda5]MC-RR (1) and [Mser7]MC-RR (8) were detected in the culture and/or field samples. This study is a good example of how commonly used targeted LC-MS methods can underestimate the diversity of MCs in freshwater lakes and cyanobacteria cultures and how untargeted LC-MS methods can be used to comprehensively assess MC diversity present in a new system.

Paralytic shellfish toxin producing Aphanizomenon gracile strains isolated from Lake Iznik, Turkey.

Aphanizomenon gracile is one of the most widespread Paralytic Shellfish Toxin (PST) producing cyanobacteria in freshwater bodies in the Northern Hemisphere. It has been shown to produce various PST congeners, including saxitoxin (STX), neosaxitoxin (NEO), decarbamoylsaxitoxin (dcSTX) and gonyautoxin 5 (GTX5) in Europe, North America and Asia. Three cyanobacteria strains were isolated in Lake Iznik in northwestern Turkey. Morphological characterization of these strains suggested all three strains conformed to classical taxonomic identification of A. gracile with some differences such as clumping of filaments, partially hyaline cells in some filaments and longer than usual vegetative cells. Sequences of 16S rRNA gene of these strains were placed within an A. gracile cluster including the majority of PST producing strains, confirming the identification of these strains as A. gracile. These new strains possessed saxitoxin biosynthesis genes sxtA, sxtG and their sequences clustered with those of other A. gracile. Liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis demonstrated the presence of NEO, STX, dcSTX and decarbamoylneosaxitoxin (dcNEO) in all strains. This is the first report of a PST producer in any water body in Turkey and first observation of dcNEO in an A. gracile culture.

Algal toxins and producers in the marine waters of Qatar, Arabian Gulf.

Harmful Algal Bloom species are ubiquitous and their blooms occur in the Arabian Gulf. In this study, two cruises were performed in 2012 and 2013 to collect phytoplankton samples from 4 sites in the Arabian Gulf. Toxin analyses of phytoplankton samples for 32 algal toxins from 5 different toxin groups were conducted on the samples using both enzyme linked immunosorbent assay (ELISA) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Results demonstrated, for the first time, the presence of paralytic shellfish toxins (PSTs), diarrhetic shellfish toxin (DST), amnesic shellfish toxin (AST), cyclic imines (CIs) and polyether-lactone toxins in freeze-dried phytoplankton samples. Four Vulcanodinium rugosum cultures were established from field samples and these proved to contain between 603 and 981 ng pinnatoxin (PnTx) H per mg dry weight in addition to being positive for portimine. These strains from Qatar clustered with strains from Japan and Florida based on large subunit rRNA and rRNA internal transcribed spacer gene sequences.

Hypoglycemia detected during cardiac arrest of a non-diabetic patient with heart failure.

Hypoglycemia in non-diabetic patients with heart failure is a rare finding. It is thought to be caused by hepatic dysfunction secondary to chronic passive congestion, and reduced gluconeogenesis. In this report we present a 23-year-old man with a history of Duchenne muscular dystrophy hospitalized for decompensated heart failure and implantable cardioverter defibrillator shock. Laboratory examination on admission showed slightly elevated levels of hepatic enzymes. Despite the therapy for heart failure the patient's clinical status deteriorated, and sinus bradycardia and then cardiac arrest occured. After successful 5-minute cardiopulmonary resuscitation, an arterial blood sample revealed metabolic acidosis with a level of pH 7.04, bicarbonate 9.3, and glucose of 22 mg/dl. Acute treatment of metabolic acidosis with hypoglycemia was successfully performed. Based on this case, possible causes of unexplained hypoglycemia in non-diabetic patients with heart failure were described in a short literature review.

Diversity of and selection acting on cylindrospermopsin cyrB gene adenylation domain sequences in Florida.

Aphanizomenon ovalisporum is the only confirmed cylindrospermopsin producer identified in the United States to date. On the other hand, Cylindrospermopsis raciborskii is a prominent feature of many lakes in Florida and other regions of the United States. To see the variation in cylindrospermopsin cyrB gene adenylation domain sequences and possibly discover new cylindrospermopsin producers, we collected water samples for a 3-year period from 17 different systems in Florida. Positive amplicons were cloned and sequenced, revealing that approximately 92% of sequences were A. ovalisporum-like (>99% identity). Interestingly, 6% of sequences were very similar (>99% identity) to cyrB sequences of C. raciborskii from Australia and of Aphanizomenon sp. from Germany. Neutrality tests suggest that A. ovalisporum-like cyrB adenylation domain sequences are under purifying selection, with abundant low-frequency polymorphisms within the population. On the other hand, when compared between species by codon-based methods, amino acids of CyrB also seem to be under purifying selection, in accordance with the one proposed amino acid thought to be activated by the CyrB adenylation domain.

Heme oxygenase 2 of the cyanobacterium Synechocystis sp. PCC 6803 is induced under a microaerobic atmosphere and is required for microaerobic growth at high light intensity.

Cyanobacteria, red algae, and cryptomonad algae utilize phycobilin chromophores that are attached to phycobiliproteins to harvest solar energy. Heme oxygenase (HO) in these organisms catalyzes the first step in phycobilin formation through the conversion of heme to biliverdin IXalpha, CO, and iron. The Synechocystis sp. PCC 6803 genome contains two open reading frames, ho1 (sll1184) and ho2 (sll1875), whose products have in vitro HO activity. We report that HO2, the protein encoded by ho2, was induced in the cells growing under a microaerobic atmosphere [0.2% (v/v) O(2)], whereas HO1 was constitutively expressed under both aerobic and microaerobic atmospheres. Light intensity did not have an effect on the expression of both the HOs. Cells, in which ho2 was disrupted, were unable to grow microaerobically at a light intensity of 40 micromol m(-2) s(-1), but did grow microaerobically at 10 micromol m(-2) s(-1) light intensity. These cells grew normally aerobically at both light intensities. Comparative analysis of complete cyanobacterial genomes revealed that possession of two HOs is common in cyanobacteria. In phylogenetic analysis of their amino acid sequences, cyanobacterial HO1 and HO2 homologs formed distinct clades. HO sequences of cyanobacteria that have only one isoform were most similar to HO1 sequences. We propose that HO2 might be the more ancient HO homolog that functioned under low O(2) tension, whereas the derived HO1 can better accommodate increased O(2) tension in the environment.

IMPROVED METHODS FOR THE ISOLATION OF CYANOBACTERIAL DNA FROM ENVIRONMENTAL SAMPLES(1).

DNA isolated from environmental samples often contains enzyme inhibitors disruptive to downstream molecular applications. Most of the existing methods of cyanobacterial DNA isolation do not effectively eliminate these inhibitors from sediment samples or cells collected from freshwater ecosystems. We describe improved methods based on the xanthogenate-SDS nucleic acid isolation (XS) method of Tillett and Neilan (2000). Our improved methods provided high-quality cyanobacterial DNA that could be amplified in PCR and digested with a restriction enzyme. Results were superior to several commercial kits. The DNA yield was also similar to that obtained via the standard XS method. These methods should provide valuable new tools for the expanded application of molecular genetics to limnological and oceanographic research.

A comparative study of Florida strains of Cylindrospermopsis and Aphanizomenon for cylindrospermopsin production.

The toxin cylindrospermopsin (CYN) is produced by a variety of cyanobacterial genera. One of these, Cylindrospermopsis raciborskii, is generally assumed to be the source of CYN in lakes and rivers in Florida, USA. However, in this study, none of the eight Florida isolates of this species tested contained the genetic determinants involved in toxin production nor did they produce CYN. We show for the first time that Aphanizomenon ovalisporum isolated from a pond in this state has the genes putatively associated with CYN production. Analysis by liquid chromatography with mass spectrometric detection (LC/MS) revealed that it produced CYN in the range of 7.39-9.33 microg mg(-1) freeze-dried cells. 16S rDNA sequences of this strain showed 99.6% and 99.9% identity to published A. ovalisporum and Anabaena bergii 16S sequences, respectively. These results help to explain the general lack of a defined relationship between the abundance of C. raciborskii in freshwater ecosystems of Florida and observed concentrations of CYN. The latter observation raises the potential that previous reports of CYN may be coincidental with unrecorded presence of another CYN-producing species.