scholarly journals Monitoring the Emergence of Algal Toxins in Shellfish: First Report on Detection of Brevetoxins in French Mediterranean Mussels

Marine Drugs ◽  
2021 ◽  
Vol 19 (7) ◽  
pp. 393
Author(s):  
Zouher Amzil ◽  
Amélie Derrien ◽  
Aouregan Terre Terrillon ◽  
Audrey Duval ◽  
Coralie Connes ◽  
...  
Keyword(s):  
Monitoring Program ◽  
Specific Area ◽  
Algal Toxins ◽  
Lipophilic Toxins ◽  
Set Up ◽  
First Time ◽  
Single Laboratory ◽  
Maximum Content ◽  
Digestive Glands

In France, four groups of lipophilic toxins are currently regulated: okadaic acid/dinophysistoxins, pectenotoxins, yessotoxins and azaspiracids. However, many other families of toxins exist, which can be emerging toxins. Emerging toxins include both toxins recently detected in a specific area of France but not regulated yet (e.g., cyclic imines, ovatoxins) or toxins only detected outside of France (e.g., brevetoxins). To anticipate the introduction to France of these emerging toxins, a monitoring program called EMERGTOX was set up along the French coasts in 2018. The single-laboratory validation of this approach was performed according to the NF V03-110 guidelines by building an accuracy profile. Our specific, reliable and sensitive approach allowed us to detect brevetoxins (BTX-2 and/or BTX-3) in addition to the lipophilic toxins already regulated in France. Brevetoxins were detected for the first time in French Mediterranean mussels (Diana Lagoon, Corsica) in autumn 2018, and regularly every year since during the same seasons (autumn, winter). The maximum content found was 345 µg (BTX-2 + BTX-3)/kg in mussel digestive glands in November 2020. None were detected in oysters sampled at the same site. In addition, a retroactive analysis of preserved mussels demonstrated the presence of BTX-3 in mussels from the same site sampled in November 2015. The detection of BTX could be related to the presence in situ at the same period of four Karenia species and two raphidophytes, which all could be potential producers of these toxins. Further investigations are necessary to understand the origin of these toxins.

scholarly journals Cyclic Imines (CIs) in Mussels from North-Central Adriatic Sea: First Evidence of Gymnodimine A in Italy

Toxins ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 370
Author(s):  
Simone Bacchiocchi ◽  
Melania Siracusa ◽  
Debora Campacci ◽  
Martina Ciriaci ◽  
Alessandra Dubbini ◽  
...  
Keyword(s):  
Food Safety ◽  
Chronic Toxicity ◽  
Adriatic Sea ◽  
Official Method ◽  
Toxicity Data ◽  
North Central ◽  
Lipophilic Toxins ◽  
Distribution Studies ◽  
First Time ◽  
Digestive Glands

Cyclic imines (CIs) are emerging marine lipophilic toxins (MLTs) occurring in microalgae and shellfish worldwide. The present research aimed to study CIs in mussels farmed in the Adriatic Sea (Italy) during the period 2014–2015. Twenty-eight different compounds belonging to spirolides (SPXs), gymnodimines (GYMs), pinnatoxins (PnTXs) and pteriatoxins (PtTXs) were analyzed by the official method for MLTs in 139 mussel samples collected along the Marche coast. Compounds including 13-desmethyl spirolide C (13-desMe SPX C) and 13,19-didesmethyl spirolide C (13,19-didesMe SPX C) were detected in 86% of the samples. The highest levels were generally reported in the first half of the year reaching 29.2 µg kg−1 in January/March with a decreasing trend until June. GYM A, for the first time reported in Italian mussels, was found in 84% of the samples, reaching the highest concentration in summer (12.1 µg kg−1). GYM A and SPXs, submitted to tissue distribution studies, showed the tendency to accumulate mostly in mussel digestive glands. Even if SPX levels in mussels were largely below the European Food Safety Authority (EFSA) reference of 400 μg SPXs kg−1, most of the samples contained CIs for the large part of the year. Since chronic toxicity data are still missing, monitoring is surely recommended.

scholarly journals New insight on the simultaneous H2 and HNO2 production in concentrated HNO3 aqueous solutions under alpha radiation

RSC Advances ◽  
2021 ◽  
Vol 11 (20) ◽  
pp. 12141-12152
Author(s):  
Raluca M. Musat ◽  
Jean-Luc Roujou ◽  
Vincent Dauvois ◽  
Muriel Ferry ◽  
Carole Marchand ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Precise Determination ◽  
Alpha Radiation ◽  
System P ◽  
Set Up ◽  
First Time

For the first time ever, a specially designed set-up, coupled to the CEMHTI cyclotron allowed in situ monitoring of HNO2 and precise determination of H2 production in the external α radiolysis of HNO3 solution, while ensuring no perturbation of the investigated system.

scholarly journals Visualizing an convergence of three mitochondrial molecule mRNAs for DRP1/MFN2/UCP4 on soma of cerebellar Purkinje cells by RNAscope

2021 ◽  
Author(s):  
Hui Liu ◽  
Tingting Luo ◽  
Feifei Wu ◽  
Baolin Guo ◽  
Kunlong Zhang ◽  
...  
Keyword(s):  
Purkinje Cells ◽  
Scoring System ◽  
Drug Targets ◽  
Structural Basis ◽  
Preclinical Development ◽  
Mitochondrial Dynamic ◽  
Set Up ◽  
Cerebellar Purkinje Cells ◽  
First Time

Abstract We know little about how mitochondrial dynamic are regulated in the Purkinje cells. To explore it, we first set up a transgenic mice in which Purkinje cells expressed tdTomato in the cerebellum of Gad2-cre;ZsGreen-tdTomatofl/fl mice. Secondly Double stainings verified tdTomato cells were Calbinin (CB)-positive Purkinje cells, but not colocalized either with astrocyte marker GFAP or with microglia marker Iba1. Thirdly, application of RNAscope in situ hybridization with the identification of mRNAs of mitochondrial fusion (Mfn2), calcium transporter (Mcu and Nclx) and uncoupling proteins (Ucp2 and Ucp4) were used onto Purkinje cells for specific spatial analysis. The RNAscope assay used a semi‑quantitative H scoring guideline to evaluate the staining results. The number of bins ranges from 0–4 according to the ACD scoring system. Moreover, ACD scoring system was used to calculate the overall H scores of Dendritic Weighted Formula (DWF) and Soma Weighted Formula (SWF). Our data for the first time demonstrated that Mfn2 mRNAs expression was evident in Prukinje cells with the H scores of DWF and SWF as 60 and 139, respectively. And few Ucp4 mRNAs expression was present in dendritic shafts of Prukinje cells with the H scores of DWF and SWF as 14 and 103, respectively. It should be noted that Mcu mRNAs, Nclx mRNAs, as well as Ucp2 mRNAs expression were only scattered on both soma and dendrites in Prukinje cells with the low H scores of DWF and SWF. Double RNAscope profiling of mitochondrial molecules showed The data showed Mfn1 mRNAs are present only in the soma of the Purkinje cells, instead of processes. Double RNAscope showed almost none of dots of Drp1 mRNAs was co-localized with dots of Mcu mRNAs, as well as almost none of dots of Ucp2 mRNAs was co-localized with dots of Mfn2 mRNAs. All of these results show the mitochondrial Drp1/Mfn2/UCP4 convergence on the Purkinje cells. Finally, a major focus of present research will be to develop new and more specific molecules that tune the activity of the Purkinje cells activate or inactivate and to address diseases for which such druglike molecules may open therapeutic windows for Purkinje cells-related manipulation in the clinic. The molecular identification of drug targets, mechanism of action, and structural basis of their activity will crucially enable preclinical development.

scholarly journals Visualizing an convergence of three mitochondrial molecule mRNAs for DRP1/MFN2/UCP4 on soma of cerebellar Purkinje cells by RNAscope

2021 ◽  
Author(s):  
Hui Liu ◽  
Tingting Luo ◽  
Feifei Wu ◽  
Baolin Guo ◽  
Kunlong Zhang ◽  
...  
Keyword(s):  
Purkinje Cells ◽  
Scoring System ◽  
Drug Targets ◽  
Structural Basis ◽  
Preclinical Development ◽  
Mitochondrial Dynamic ◽  
Set Up ◽  
Cerebellar Purkinje Cells ◽  
First Time

Abstract We know little about how mitochondrial dynamic are regulated in the Purkinje cells. To explore it, we first set up a transgenic mice in which Purkinje cells expressed tdTomato in the cerebellum of Gad2-cre;ZsGreen-tdTomatofl/fl mice. Secondly Double stainings verified tdTomato cells were Calbinin (CB)-positive Purkinje cells, but not colocalized either with astrocyte marker GFAP or with microglia marker Iba1. Thirdly, application of RNAscope in situ hybridization with the identification of mRNAs of mitochondrial fusion (Mfn2), calcium transporter (Mcu and Nclx) and uncoupling proteins (Ucp2 and Ucp4) were used onto Purkinje cells for specific spatial analysis. The RNAscope assay used a semi‑quantitative H scoring guideline to evaluate the staining results. The number of bins ranges from 0–4 according to the ACD scoring system. Moreover, ACD scoring system was used to calculate the overall H scores of Dendritic Weighted Formula (DWF) and Soma Weighted Formula (SWF). Our data for the first time demonstrated that Mfn2 mRNAs expression was evident in Prukinje cells with the H scores of DWF and SWF as 60 and 139, respectively. And few Ucp4 mRNAs expression was present in dendritic shafts of Prukinje cells with the H scores of DWF and SWF as 14 and 103, respectively. It should be noted that Mcu mRNAs, Nclx mRNAs, as well as Ucp2 mRNAs expression were only scattered on both soma and dendrites in Prukinje cells with the low H scores of DWF and SWF. Double RNAscope profiling of mitochondrial molecules showed The data showed Mfn1 mRNAs are present only in the soma of the Purkinje cells, instead of processes. Double RNAscope showed almost none of dots of Drp1 mRNAs was co-localized with dots of Mcu mRNAs, as well as almost none of dots of Ucp2 mRNAs was co-localized with dots of Mfn2 mRNAs. All of these results show the mitochondrial Drp1/Mfn2/UCP4 convergence on the Purkinje cells. Finally, a major focus of present research will be to develop new and more specific molecules that tune the activity of the Purkinje cells activate or inactivate and to address diseases for which such druglike molecules may open therapeutic windows for Purkinje cells-related manipulation in the clinic. The molecular identification of drug targets, mechanism of action, and structural basis of their activity will crucially enable preclinical development.

scholarly journals Stability of a Rock Tunnel Passing through Talus-Like Formations: A Case Study in Southwestern China

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Shaoqiang Zhang ◽  
Wenqiang Li ◽  
Jiashan Tan ◽  
Bokuan Li ◽  
Xiaochang Li ◽  
...  
Keyword(s):  
Rock Mass ◽  
Rock Pressure ◽  
Monitoring Program ◽  
Surrounding Rock ◽  
In Situ Monitoring ◽  
Monitoring Data ◽  
Surrounding Rock Pressure ◽  
Set Up ◽  
Highway Project

Tayi tunnel is one of the component tunnels in the Jian-Ge-Yuan Highway Project located in Yunnan Province, southeast of China. It mainly passes through talus-like formations comprised of rock blocks of diverse sizes and weak interlayers with clayey soils with different fractions. Such a special composition leads to the loose and fractured structure of talus-like formations, which is highly sensitive to the excavation perturbation. Therefore, Tayi tunnel has become the controlled pot of the whole highway project as the construction speed has to be slowed down to reduce the deformation of surrounding talus-like rock mass. To better understand the tunnel-induced ground response and the interaction between the surrounding rock mass and tunnel lining, a comprehensive in situ monitoring program was set up. The in situ monitoring contents included the surrounding rock pressure on the primary lining, the primary lining deformation, and the stress of steel arches. Based on the monitoring data, the temporal and the long-term spatial characteristics of mechanical behavior of surrounding rock mass and lining structure due to the excavation process were analyzed and discussed. It is found that the excavation of lower benches released the surrounding rock pressure around upper benches, resulting in the decrease of the surrounding rock pressure on the primary lining and the stress of steel arches. In addition, the monitoring data revealed that the primary lining sustained bias pressure from the surrounding rock mass, which thereby caused unsymmetrical deformation of the primary lining, in accordance with the monitored displacement data. A dynamically adaptive support system was implemented to strengthen the bearing capacity of the lining system especially in the region of an extremely weak rock mass. After such treatment, the deformation of the primary lining has been well controlled and the construction speed has been considerably enhanced.

Cobalt/Lewis Acid Catalysis for Hydrocarbofunctionalization of Alkynes via Cooperative C–H Activation

2020 ◽  
Author(s):  
Chang-Sheng Wang ◽  
Sabrina Monaco ◽  
Anh Ngoc Thai ◽  
Md. Shafiqur Rahman ◽  
Chen Wang ◽  
...  
Keyword(s):  
Catalytic System ◽  
Lewis Acid ◽  
Hydrogen Transfer ◽  
Acid Catalysis ◽  
Rate Limiting Step ◽  
Site Selectivity ◽  
Set Up ◽  
Site Selective ◽  
First Time ◽  
Rate Limiting

A catalytic system comprised of a cobalt-diphosphine complex and a Lewis acid (LA) such as AlMe3 has been found to promote hydrocarbofunctionalization reactions of alkynes with Lewis basic and electron-deficient substrates such as formamides, pyridones, pyridines, and azole derivatives through site-selective C-H activation. Compared with known Ni/LA catalytic system for analogous transformations, the present catalytic system not only feature convenient set up using inexpensive and bench-stable precatalyst and ligand such as Co(acac)3 and 1,3-bis(diphenylphosphino)propane (dppp), but also display distinct site-selectivity toward C-H activation of pyridone and pyridine derivatives. In particular, a completely C4-selective alkenylation of pyridine has been achieved for the first time. Mechanistic stidies including DFT calculations on the Co/Al-catalyzed addition of formamide to alkyne have suggested that the reaction involves cleavage of the carbamoyl C-H bond as the rate-limiting step, which proceeds through a ligand-to-ligand hydrogen transfer (LLHT) mechanism leading to an alkyl(carbamoyl)cobalt intermediate.

Probing the Dynamic Self-Assembly Behaviour of Photoswitchable Wormlike Micelles in Real Time

2018 ◽  
Author(s):  
Elaine A. Kelly ◽  
Judith E. Houston ◽  
Rachel Evans
Keyword(s):  
Real Time ◽  
Absorption Spectroscopy ◽  
Self Assembly ◽  
Uv Light ◽  
Wormlike Micelles ◽  
Tetraethylene Glycol ◽  
Light Illumination ◽  
First Time ◽  
Dependent Processes

Understanding the dynamic self-assembly behaviour of azobenzene photosurfactants (AzoPS) is crucial to advance their use in controlled release applications such as<i></i>drug delivery and micellar catalysis. Currently, their behaviour in the equilibrium <i>cis-</i>and <i>trans</i>-photostationary states is more widely understood than during the photoisomerisation process itself. Here, we investigate the time-dependent self-assembly of the different photoisomers of a model neutral AzoPS, <a>tetraethylene glycol mono(4′,4-octyloxy,octyl-azobenzene) </a>(C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>) using small-angle neutron scattering (SANS). We show that the incorporation of <i>in-situ</i>UV-Vis absorption spectroscopy with SANS allows the scattering profile, and hence micelle shape, to be correlated with the extent of photoisomerisation in real-time. It was observed that C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>could switch between wormlike micelles (<i>trans</i>native state) and fractal aggregates (under UV light), with changes in the self-assembled structure arising concurrently with changes in the absorption spectrum. Wormlike micelles could be recovered within 60 seconds of blue light illumination. To the best of our knowledge, this is the first time the degree of AzoPS photoisomerisation has been tracked <i>in</i><i>-situ</i>through combined UV-Vis absorption spectroscopy-SANS measurements. This technique could be widely used to gain mechanistic and kinetic insights into light-dependent processes that are reliant on self-assembly.

The Total Synthesis of Rhabdastrellic Acid A

2018 ◽  
Author(s):  
Yaroslav Boyko ◽  
Christopher Huck ◽  
David Sarlah
Keyword(s):  
Total Synthesis ◽  
Late Stage ◽  
Cross Coupling ◽  
Side Chains ◽  
General Strategy ◽  
Modular Approach ◽  
Linear Sequence ◽  
Generating Sequence ◽  
First Time

<div>The first total synthesis of rhabdastrellic acid A, a highly cytotoxic isomalabaricane triterpenoid, has been accomplished in a linear sequence of 14 steps from commercial geranylacetone. The prominently strained <i>trans-syn-trans</i>-perhydrobenz[<i>e</i>]indene core characteristic of the isomalabaricanes is efficiently accessed in a selective manner for the first time through a rapid, complexity-generating sequence incorporating a reductive radical polyene cyclization, an unprecedented oxidative Rautenstrauch cycloisomerization, and umpolung 𝛼-substitution of a <i>p</i>-toluenesulfonylhydrazone with in situ reductive transposition. A late-stage cross-coupling in concert with a modular approach to polyunsaturated side chains renders this a general strategy for the synthesis of numerous family members of these synthetically challenging and hitherto inaccessible marine triterpenoids.</div>

scholarly journals Comparison of Hydrocarbon-Degrading Consortia from Surface and Deep Waters of the Eastern Mediterranean Sea: Characterization and Degradation Potential

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2246
Author(s):  
Georgia Charalampous ◽  
Efsevia Fragkou ◽  
Konstantinos A. Kormas ◽  
Alexandre B. De Menezes ◽  
Paraskevi N. Polymenakou ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Oil Spills ◽  
Eastern Mediterranean ◽  
Sole Source ◽  
Eastern Mediterranean Sea ◽  
Deep Waters ◽  
Degradation Rates ◽  
Polycyclic Aromatic ◽  
Set Up

The diversity and degradation capacity of hydrocarbon-degrading consortia from surface and deep waters of the Eastern Mediterranean Sea were studied in time-series experiments. Microcosms were set up in ONR7a medium at in situ temperatures of 25 °C and 14 °C for the Surface and Deep consortia, respectively, and crude oil as the sole source of carbon. The Deep consortium was additionally investigated at 25 °C to allow the direct comparison of the degradation rates to the Surface consortium. In total, ~50% of the alkanes and ~15% of the polycyclic aromatic hydrocarbons were degraded in all treatments by Day 24. Approximately ~95% of the total biodegradation by the Deep consortium took place within 6 days regardless of temperature, whereas comparable levels of degradation were reached on Day 12 by the Surface consortium. Both consortia were dominated by well-known hydrocarbon-degrading taxa. Temperature played a significant role in shaping the Deep consortia communities with Pseudomonas and Pseudoalteromonas dominating at 25 °C and Alcanivorax at 14 °C. Overall, the Deep consortium showed a higher efficiency for hydrocarbon degradation within the first week following contamination, which is critical in the case of oil spills, and thus merits further investigation for its exploitation in bioremediation technologies tailored to the Eastern Mediterranean Sea.

scholarly journals Engineered Phage Endolysin Eliminates Gardnerella Biofilm without Damaging Beneficial Bacteria in Bacterial Vaginosis Ex Vivo

Pathogens ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 54
Author(s):  
Christine Landlinger ◽  
Lenka Tisakova ◽  
Vera Oberbauer ◽  
Timo Schwebs ◽  
Abbas Muhammad ◽  
...  
Keyword(s):  
Bacterial Vaginosis ◽  
Bactericidal Activity ◽  
High Selectivity ◽  
Ex Vivo ◽  
Vaginal Microbiome ◽  
Wild Type ◽  
Wild Type Enzyme ◽  
Promising Alternative ◽  
First Time

Bacterial vaginosis is characterized by an imbalance of the vaginal microbiome and a characteristic biofilm formed on the vaginal epithelium, which is initiated and dominated by Gardnerella bacteria, and is frequently refractory to antibiotic treatment. We investigated endolysins of the type 1,4-beta-N-acetylmuramidase encoded on Gardnerella prophages as an alternative treatment. When recombinantly expressed, these proteins demonstrated strong bactericidal activity against four different Gardnerella species. By domain shuffling, we generated several engineered endolysins with 10-fold higher bactericidal activity than any wild-type enzyme. When tested against a panel of 20 Gardnerella strains, the most active endolysin, called PM-477, showed minimum inhibitory concentrations of 0.13–8 µg/mL. PM-477 had no effect on beneficial lactobacilli or other species of vaginal bacteria. Furthermore, the efficacy of PM-477 was tested by fluorescence in situ hybridization on vaginal samples of fifteen patients with either first time or recurring bacterial vaginosis. In thirteen cases, PM-477 killed the Gardnerella bacteria and physically dissolved the biofilms without affecting the remaining vaginal microbiome. The high selectivity and effectiveness in eliminating Gardnerella, both in cultures of isolated strains as well as in clinically derived samples of natural polymicrobial biofilms, makes PM-477 a promising alternative to antibiotics for the treatment of bacterial vaginosis, especially in patients with frequent recurrence.

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