Allelopathy, the release of extracellular compounds that inhibit the growth of other microorganisms, may be one factor contributing to the formation and/or maintenance of cyanobacterial blooms. We ...investigated the allelopathic effects of three cyanobacterial species (
Nodularia spumigena, Aphanizomenon flos-aquae and
Anabaena lemmermannii) that frequently form mass-occurrences in the Baltic Sea. We exposed monocultures of three phytoplankton species (
Thalassiosira weissflogii,
Rhodomonas sp. and
Prymnesium parvum) to cell-free filtrates of the three cyanobacteria, and quantified allelopathic effects with cell counts. We also investigated the role of the growth phase of cyanobacteria in their allelopathy, by comparing the effects of an exponential and a stationary phase culture of
N. spumigena. All tested cyanobacteria inhibited the growth of
Rhodomonas sp., but none of them affected
P. parvum. The effects on
T. weissflogii were more variable, and they were amplified by repeated filtrate additions compared to a single filtrate addition.
N. spumigena was more allelopathic in exponential than in stationary growth phase, whereas the culture filtrate was more hepatotoxic in stationary phase. Hepatotoxins were thus probably not involved in the allelopathic effects, which is also indicated by the allelopathic properties of the non-toxic
A. flos-aquae and
A. lemmermannii. The results demonstrate that the common Baltic cyanobacteria affect some coexisting phytoplankton species negatively. Allelopathy may therefore play a role in interspecific competition and contribute to cyanobacterial bloom maintenance.
The risk of liver injury associated with the use of herbal medicinal products (HMPs) is well known among physicians caring for patients under a HMP therapy, as documented in case reports or case ...series and evidenced by using the Roussel Uclaf Causality Assessment Method (RUCAM) to verify a causal relationship. In many cases, however, the quality of HMPs has rarely been considered regarding potential culprits such as contaminants and toxins possibly incriminated as causes for the liver injury. This review aims to comprehensively assemble details of tentative hepatotoxic contaminants and toxins found in HMPs. Based on the origin, harmful agents may be divided according two main sources, namely the phyto-hepatotoxin and the nonphyto-hepatotoxin groups. More specifically, phyto-hepatotoxins are phytochemicals or their metabolites naturally produced by plants or internally in response to plant stress conditions. In contrast, nonphyto-hepatotoxic elements may include contaminants or adulterants occurring during collection, processing and production, are the result of accumulation of toxic heavy metals by the plant itself due to soil pollutions, or represent mycotoxins, herbicidal and pesticidal residues. The phyto-hepatotoxins detected in HMPs are classified into eight major groups consisting of volatile compounds, phytotoxic proteins, glycosides, terpenoid lactones, terpenoids, alkaloids, anthraquinones, and phenolic acids. Nonphyto-hepatotoxins including metals, mycotoxins, and pesticidal and herbicidal residues and tentative mechanisms of toxicity are discussed. In conclusion, although a variety of potential toxic substances may enter the human body through HMP use, the ability of these toxins to trigger human liver injury remains largely unclear.
•An NIR-II nanoprobe was designed to monitor the ONOO¯ in the liver of living mice.•The paracetamol-induced liver injury can be monitored in situ by the nanoprobe.•The probe enabled early diagnosis ...of liver injury prior to physiological disorder.•The probe successfully screened the hepatotoxic components from natural medicines.
Herbal medicines and dietary supplements are widely used worldwide. However, reports have revealed that a large number of herbal medicines are implicated in the hepatic damage, which is referred to as Herbal medicines-induced liver injury (HILI). Traditional diagnostic methods for HILI include histological and serological assessments, which fail to offer real-time and unambiguous visualization of hepatotoxicity in vivo. Herein, we constructed a second near-infrared (NIR-II) luminescent nanoprobes to achieve accurate, high-efficiency, and non-invasive detection of HILI by the assembly of lanthanide-based NIR-II luminescence nanoparticles with a chromophore with absorption band in the NIR-II region. Specifically, the NIR-II luminescence of the lanthanide nanoparticles can be effectively quenched by the chromophores on the surface of nanoparticles via an absorption competition-induced quenching effect, and subsequently recovered by the pathophysiological biomarker peroxynitrite (ONOO−) generated in early HILI. It is demonstrated that the nanoprobes are capable for the screening of liver toxins in a noninvasive pattern, which is more convenient than the conventional diagnostic approaches. Finally, our luminescence detection approach offers an immediate testing technique for the identification of hepatotoxic components of herbal medicine such as colchicine, monocrotaline and stibene glucoside, providing a high-throughput screening strategy for herbal medicine-induced hepatotoxicity.
In order to evaluate hepatoprotective function, both in vitro and in vivo liver or hepatoprotective models have been constructed in the past. These methods examine a drug's potential to prevent or ...minimize liver damage in test animals. To express their effectiveness and safety in humans, new drugs must first travel through a number of developmental phases, beginning with the identification of their pharmacological characteristics in cellular and animal models. In the medical literature, there are many methods for measuring hepatoprotective efficacy in vivo and in vitro. Fresh hepatocytes are exposed to hepatotoxin treatment in in vitro models, and the effects of the test chemical on those cells are examined. To elicit liver damage in test animals, dangerous dosages of an identified hepatotoxin are administered in in vivo models. The test material is provided before, after, and simultaneously with the toxin treatment. Hepatitis in Long Evans and other chemical agents are commonly exploited to generate hepatotoxicity in experimental animals for the evaluation of hepatoprotective medications. Cinnamon rats, liver cirrhosis and necrosis, hepatic fibrosis brought on by carbon tetrachloride in rats, liver cirrhosis brought on by galactosamine, inhibition of proline hydroxylation, trans-heptic investigations model in dogs, etc. The many forms of in vivo and in vitro hepatoprotective screening models are explained in this article.
In this work, a chemiluminescence (CL) aptasensor was designed for detection of microcystin-RR (MC-RR) by introducing Cu/Co nanorods acting as CL catalyzer. Cu/Co nanorods were firstly synthesized ...throughout a hydrothermal method. Then the thiolated MC-RR aptamer was immobilized on the surface of Cu/Co nanorods, which was employed for recognizing of MC-RR target. In the presence of MC-RR, the conformational change of MC-RR aptamer was happened via recognizing between MC-RR and its aptamer. The luminol CL was catalyzed by Cu/Co nanorods that influenced by conformational change of MC-RR aptamer. The formed MC-RR/aptamer composite prevented the diffusion channel of luminol substrate toward the Cu/Co nanorods surface and restrained the Cu/Co nanorods catalyzing luminol CL. And the intensity of CL depended on the concentration of MC-RR. Under optimal condition, the CL aptasensor had a linear range in 0.1 to 70 nM and a low detection limit of 3.3 × 10−11 M for MC-RR. This study provided a significant method for MC-RR detection in real samples with excellent selectivity.
•Cu/Co BNMs had superior over Cu, Co monometallic nanomaterials and Co(NO3)2, Cu(NO3)2.•Cu/Co nanorods were used as nanocatalysts and the carrier for CL detection.•LOD for Microcystin-RR 33 fM was gained.
Freshwater cyanobacteria produce highly toxic secondary metabolites, which can be transported downstream by rivers and waterways into the sea. Estuarine and coastal aquaculture sites exposed to toxic ...cyanobacteria raise concerns that shellfish may accumulate and transfer cyanotoxins in the food web. This study aims to describe the competitive pattern of uptake and depuration of a wide range of microcystins (MC-LR, MC-LF, MC-LW, MC-LY, Asp3-MC-LR/Dha7-MC-LR, MC-HilR) and nodularins (NOD cyclic and linear) within the common blue mussel Mytilus edulis exposed to a combined culture of Microcystis aeruginosa and Nodularia spumigena into the coastal environment.
Different distribution profiles of MCs/NODs in the experimental system were observed. The majority of MCs/NODs were present intracellularly which is representative of healthy cyanobacterial cultures, with MC-LR and NOD the most abundant analogues. Higher removal rate was observed for NOD (≈96%) compared to MCs (≈50%) from the water phase. Accumulation of toxins in M. edulis was fast, reaching up to 3.4 μg/g shellfish tissue four days after the end of the 3-days exposure period, with NOD (1.72 μg/g) and MC-LR (0.74 μg/g) as the dominant toxins, followed by MC-LF (0.35 μg/g) and MC-LW (0.31 μg/g). Following the end of the exposure period depuration was incomplete after 27 days (0.49 μg/g of MCs/NODs). MCs/NODs were also present in faecal material and extrapallial fluid after 24 h of exposure with MCs the main contributors to the total cyanotoxin load in faecal material and NOD in the extrapallial fluid. Maximum concentration of MCs/NODs accumulated in a typical portion of mussels (20 mussels, ≈4 g each) was beyond greater the acute, seasonal and lifetime tolerable daily intake. Even after 27 days of depuration, consuming mussels harvested during even short term harmful algae blooms in close proximity to shellfish beds might carry a high health risk, highlighting the need for testing.
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•MCs/NODs were present in M. edulis tissue, faecal material and extrapallial fluid after 24 h of exposure.•Depuration of MCs/NODs was incomplete after 27 days.•MCs/NODs distributed differently in the experimental system.•Consumption of M. edulis harvested after a short term HAB can pose a human and animal health risk.
Accumulation of freshwater cyanotoxins in marine mussels is fast but depuration is slow what could result in high health risk for wildlife and humans, highlighting the need for testing.
The traditional genus Aphanizomenon comprises a group of filamentous nitrogen-fixing cyanobacteria of which several memebers are able to develop blooms and to produce toxic metabolites (cyanotoxins), ...including hepatotoxins (microcystins), neurotoxins (anatoxins and saxitoxins) and cytotoxins (cylindrospermopsin). This genus, representing geographically widespread and extensively studied cyanobacteria, is in fact heterogeneous and composed of at least five phylogenetically distant groups (Aphanizomenon, Anabaena/Aphanizomenon like cluster A, Cuspidothrix, Sphaerospermopsis and Chrysosporum) whose taxonomy is still under revision. This review provides a thorough insight into the phylogeny, ecology, biogeography and toxicogenomics (cyr, sxt, and ana genes) of the five best documented “Aphanizomenon” species with special relevance for water risk assessment: Aphanizomenon flos-aquae, Aphanizomenon gracile, Cuspidothrix issatschenkoi, Sphaerospermopsis aphanizomenoides and Chrysosporum ovalisporum. Aph. flos-aquae, Aph. gracile and C. issatschenkoi have been reported from temperate areas only whereas S. aphanizomenoides shows the widest distribution from the tropics to temperate areas. Ch. ovalisporum is found in tropical, subtropical and Mediterranean areas. While all five species show moderate growth rates (0.1–0.4day−1) within a wide range of temperatures (15–30°C), Aph. gracile and A. flos-aquae can grow from around (or below) 10°C, whereas Ch. ovalisporum and S. aphanizomenoides are much better competitors at high temperatures over 30°C or even close to 35°C. A. gracile has been confirmed as the producer of saxitoxins and cylindrospermopsin, C. issatschenkoi of anatoxins and saxitoxins and Ch. ovalisporum of cylindrospermopsin. The suspected cylindrospermopsin or anatoxin-a production of A. flos-aquae or microcystin production of S. aphanizomenoides is still uncertain. This review includes a critical discussion on the the reliability of toxicity reports and on the invasive potential of “Aphanizomenon” species in a climate change scenario, together with derived knowledge gaps and research needs. As a whole, this work is intended to represent a key reference for scientists and water managers involved in the major challenges of identifying, preventing and mitigating toxic Aphanizomenon blooms.
Toxin-producing cyanobacteria can be harmful to aquatic biota, although some grazers utilize them with often beneficial effects on their growth and reproduction. It is commonly assumed that gut ...microbiota facilitates host adaptation to the diet; however, the evidence for adaptation mechanisms is scarce. Here, we investigated the abundance of
genes in the gut of the Baltic copepods
and
during cyanobacteria bloom season (August) and outside it (February). The
genes are unique to microcystin and nodularin degraders, thus indicating the capacity to break down these toxins by the microbiota. The
genes were expressed in the copepod gut year-round, being >10-fold higher in the summer than in the winter populations. Moreover, they were significantly more abundant in
than
. To understand the ecological implications of this variability, we conducted feeding experiments using summer- and winter-collected copepods to examine if/how the
abundance in the microbiota affect: (1) uptake of toxic
, (2) uptake of a non-toxic algal food offered in mixtures with
, and (3) concomitant growth potential in the copepods. The findings provide empirical evidence that the occurrence of
genes in the copepod microbiome facilitates nutrient uptake and growth when feeding on phytoplankton mixtures containing nodularin-producing cyanobacteria; thus, providing an adaptation mechanism to the cyanobacteria blooms.
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