Flat-band localization and interaction-induced delocalization of photons.

Lattices with dispersionless, or flat, energy bands have attracted substantial interest in part due to the strong dependence of particle dynamics on interactions. Using superconducting circuits, we experimentally study the dynamics of one and two particles in a single plaquette of a lattice whose band structure consists entirely of flat bands. We first observe strictly localized dynamics of a single particle, the hallmark of all-bands-flat physics. Upon initializing two particles on the same site, we see an interaction-enabled delocalized walk across the plaquette. We further find localization in Fock space for two particles initialized on opposite sides of the plaquette. These results mark the first experimental observation of a quantum walk that becomes delocalized due to interactions and establishes a key building block in superconducting circuits for studying flat-band dynamics with strong interactions.

Changes in the morphology and cell ultrastructure of a microalgal community exposed to a commercial glyphosate formulation and a toxigenic cyanobacterium.

Human activities significantly influence the health of aquatic ecosystems because many noxious chemical wastes are discharged into freshwater bodies. Intensive agriculture contributes to the deterioration by providing indirectly fertilizers, pesticides, and other agrochemicals that affect the aquatic biota. Glyphosate is one of the most used herbicides worldwide, and microalgae are particularly sensitive to its formulation, inducing displacement of some green microalgae from the phytoplankton that leads to alterations in the floristic composition, which fosters the abundance of cyanobacteria, some of which can be toxigenic. The combination of chemical stressors such as glyphosate and biological ones, like cyanotoxins and other secondary metabolites of cyanobacteria, could induce a combined effect potentially more noxious to microalgae, affecting not only their growth but also their physiology and morphology. In this study, we evaluated the combined effect of glyphosate (Faena®) and a toxigenic cyanobacterium on the morphology and ultrastructure of microalgae in an experimental phytoplankton community. For this purpose, Microcystis aeruginosa (a cosmopolitan cyanobacterium that forms harmful blooms) and the microalgae Ankistrodesmus falcatus, Chlorella vulgaris, Pseudokirchneriella subcapitata, and Scenedesmus incrassatulus were cultivated, individually and jointly, exposing them to sub-inhibitory concentrations of glyphosate (IC10, IC20, and IC40). Effects were evaluated through scanning electron (SEM) and transmission electron (TEM) microscopy. Exposure to Faena® produced alterations in the external morphology and ultrastructure of microalgae both individually and in combined cultures. SEM evidenced the loss of the typical shape and integrity of the cell wall and an increase in the biovolume. TEM revealed reduction and disorganization of the chloroplast, variation in starch and polyphosphate granules, formation of vesicles and vacuoles, cytoplasm degradation, and cell wall continuity loss. The presence of M. aeruginosa was, for microalgae, an additional stress factor adding to the chemical stress produced by Faena®, increasing the damage in their morphology and ultrastructure. These results alert to the effects that can be caused by glyphosate and the presence of toxigenic bacteria on the algal phytoplankton in contaminated and anthropic and eutrophic freshwater ecosystems.

HIPEC in Ovarian Cancer Is the Future and Always Will Be? Results from a Spanish Multicentric Survey.

Ovarian cancer is the leading cause of death due to gynecological tumors in the female population. Despite optimal first-line treatment, including cytoreduction and platinum-based systemic chemotherapy, recurrences are frequent. The use of hyperthermic intraperitoneal chemotherapy (HIPEC) has been criticized, especially because of the lack of randomized controlled trials (RCTs) with convincing results to support the use of HIPEC in patients with ovarian cancer with peritoneal dissemination. In 2018, the clinical trial published by Van Driel et al. reported improved outcomes in favor of HIPEC treatment with cisplatin. In this study, we conducted a national survey within the Spanish group of peritoneal surgical oncology (Grupo Español de Cirugía Oncológica Peritoneal, GECOP) to explore the impact of the results of this RCT on clinical practice. A total of 33 groups completed the survey. Routine clinical practice was not changed in 28 of the 33 groups (85%) based on the results of the Van Driel trial. Despite the results of this RCT, most groups considered that more RCTs are needed and that, in the future, HIPEC may become the standard of care. In conclusion, the results from RCTs evaluating HIPEC treatment in patients with ovarian cancer has not been transferred to clinical practice.

Human footprint on the water quality from the northern Antarctic Peninsula region.

This study assessed the human footprint on the chemical pollution of Antarctic waters by characterizing inorganic chemicals and selected organic anthropogenic contaminants of emerging concern (CECs) in inland freshwater and coastal seawater and the associated ecotoxicological risk. Nicotine and tolytriazole, present in 74% and 89% of the samples analyzed, respectively, were the most ubiquitous CECs in the investigated area. The most abundant CECs were citalopram, clarithromycin, and nicotine with concentrations reaching 292, 173, and 146 ng/L, respectively. The spatial distribution of CECs was not linked to any water characteristic or inorganic component. The contamination pattern by CECs in inland freshwater varied among locations, whereas it was very similar in coastal seawater. This suggests that concentrations in inland freshwater may be ruled by environmental processes (reemission from ice, atmospheric deposition, limited photo- and biodegradation processes, etc.) in addition to human activities. Following risk assessment, citalopram, clarithromycin, nicotine, venlafaxine, and hydrochlorothiazide should be considered of concern in this area, and hence, included in future monitoring of Antarctic waters and biota. This work provides evidence on the fact that current measures taken to protect the pristine environment of Antarctica from human activities are not effective to avoid CEC spread in its aquatic environment.

Commercial pesticides for urban applications induced population growth and sub-cellular alterations in Raphidocelis subcapitata (Chlorophyceae) at concerning environmental concentrations.

Information regarding the safety and environmental risks of pesticides intended for urban use remains limited. This study aimed to assess the effects of four common pesticides on the microalga Raphidocelis subcapitata: DIAZINON® 25% C. E., Roundup®, URBACIN® 20C. E., and VAPODEL® 20% C. E., which are commercial formulations of diazinon, glyphosate, dichlorvos, and cypermethrin, respectively. According to 96-h inhibition of population growth bioassays, the four pesticide toxicities exemplified the following order: DIAZINON® (diazinon) > Roundup® (glyphosate) > VAPODEL® (dichlorvos) > URBACIN® (cypermethrin). Increasing pesticide concentrations elicited alterations in the specific growth rates (µmax). The macromolecule contents and photosynthetic pigments increased in groups exposed to the highest concentrations of DIAZINON® 25%, Roundup®, and URBACIN® 20 compared to the control group, despite these treatments inducing lower population growth rates. VAPODEL® 20% induced higher growth rates and lower macromolecule content compared to the control. Since active ingredients were not quantified, certain comparisons may prove limiting, but it is important to assess the effects of the whole mixtures in the form that they enter the environment, especially for urban-intended applications or generic formulations with higher additive contents. Finally, this study demonstrated that commercial pesticide formulations designed for urban applications might pose a threat to freshwater microalgae due to their underestimated toxic potential, but further studies are required.

Interval cytoredutive surgery and HIPEC in advanced ovarian cancer with small-bowel disease: results and reflections

Introduction: Small-bowel involvement in patients with ovarian cancer has been strongly correlated with the possibility of cytoreduction and thus with survival. The main objective of this study was to evaluate the prognostic significance of small-bowel involvement in patients undergoing optimal-complete interval cytoreductive surgery (CRS) and Hyperthermic Intraperitoneal Chemotherapy (HIPEC).Methods: We included a series of patients diagnosed with stage IIIC-IVA (pleural effusion) high-grade serous epithelial ovarian cancer and in whom CRS + HIPEC was indicated after neoadjuvant systemic chemotherapy (NACT). The study period extended from January 2008 to January 2020, with a minimum follow-up of 12 months from the inclusion of the last patient. A multivariate analysis using Cox regression allowed us to identify the variables that were independently related to disease-free survival.Results: A total of 144 patients were selected, 13 (9%) of whom were excluded from the analysis, because their disease was considered unresectable. The study included a series of 131 patients with a median age of 62 years (34-79 years) and a median Peritoneal Cancer Index (PCI) calculated during surgery of 9 (1-35). The median PCI of bowel areas 9-12 (SB-PCI) was 3 (1-10). Performance of a CC-1 cytoreduction (HR: 1.93, 95% CI: 1.02-3.64, p = 0.042) and SB-PCI greater than 3 (HR: 2.25, 95%CI: 1.13-4.48, p = 0.21) were independent factors associated with shorter disease-free survival.Conclusion: Small-bowel involvement, even in patients with a macroscopically complete resection, showed a correlation with worse prognostic outcomes and could be considered as a variable in the postoperative management of these patients. (AU)

Soil-landform-vegetation interplays at Stinker Point, Elephant Island, Antarctica.

The geomorphic dynamics on ice-free areas are crucial for understanding soil formation, vegetation and landscape stability in maritime Antarctic. We aimed to describe the soil formation on different landforms, following the Holocene glacial retreat at Stinker Point. Twenty profiles were sampled and classified, grouped into three landforms units: middle platforms and scarps, till/glacial deposits and present/Holocene raised beaches. Soil chemical and physical attributes were determined, and the vegetation type identified and quantified. Soils from till and glacial deposits can be separated by the age of exposure: older soils are stony, skeletic; and recently exposed till has soils with moderate depth, alkaline reaction and very high base saturation. Soils at the middle platforms are shallow, coarse-grained, skeletic, with abundant vegetation. Soils from the present-day beaches are alkaline, very coarse with no horizon differentiation, whereas soils on Holocene beaches are acid and nutrient-rich due to past or present-day influence of fauna. Soils from Stinker Point are generally shallow, skeletic and strongly related to the landforms and biogenic influences. Compared with other islands of the South Shetlands, in Elephant Island soil development is less pronounced, being this mainly attributed to the metamorphic nature of parent material, with greater resistance to weathering.

Occurrence of BMAA Isomers in Bloom-Impacted Lakes and Reservoirs of Brazil, Canada, France, Mexico, and the United Kingdom.

The neurotoxic alkaloid ß-N-methyl-amino-l-alanine (BMAA) and related isomers, including N-(2-aminoethyl glycine) (AEG), ß-amino-N-methyl alanine (BAMA), and 2,4-diaminobutyric acid (DAB), have been reported previously in cyanobacterial samples. However, there are conflicting reports regarding their occurrence in surface waters. In this study, we evaluated the impact of amending lake water samples with trichloroacetic acid (0.1 M TCA) on the detection of BMAA isomers, compared with pre-existing protocols. A sensitive instrumental method was enlisted for the survey, with limits of detection in the range of 5−10 ng L−1. Higher detection rates and significantly greater levels (paired Wilcoxon's signed-rank tests, p < 0.001) of BMAA isomers were observed in TCA-amended samples (method B) compared to samples without TCA (method A). The overall range of B/A ratios was 0.67−8.25 for AEG (up to +725%) and 0.69−15.5 for DAB (up to +1450%), with absolute concentration increases in TCA-amended samples of up to +15,000 ng L−1 for AEG and +650 ng L−1 for DAB. We also documented the trends in the occurrence of BMAA isomers for a large breadth of field-collected lakes from Brazil, Canada, France, Mexico, and the United Kingdom. Data gathered during this overarching campaign (overall, n = 390 within 45 lake sampling sites) indicated frequent detections of AEG and DAB isomers, with detection rates of 30% and 43% and maximum levels of 19,000 ng L−1 and 1100 ng L−1, respectively. In contrast, BAMA was found in less than 8% of the water samples, and BMAA was not found in any sample. These results support the analyses of free-living cyanobacteria, wherein BMAA was often reported at concentrations of 2−4 orders of magnitude lower than AEG and DAB. Seasonal measurements conducted at two bloom-impacted lakes indicated limited correlations of BMAA isomers with total microcystins or chlorophyll-a, which deserves further investigation.

Assessing the Ameliorative Effect of Selenium Cinnamomum verum, Origanum majorana, and Origanum vulgare Nanoparticles in Diabetic Zebrafish (Danio rerio).

Cinnamomum verum, Origanum majorana, and Origanum vulgare have been used in traditional medicine for a long time to treat diabetes because of their promising therapeutic effects. The combination of these plants (COO) was tested to improve their efficacy using selenium nanoparticles (Se-COO-NPs) and gum Arabic (GA) as stabilizers for sustained release. Phenolic compounds of plants were identified using liquid chromatography-mass spectrometry (LC-MS/MS). GA-Se-COO-NPs were characterized by spectroscopic and microscopic methods and evaluated in diabetic zebrafish. The ultraviolet spectrum was assessed to confirm the formation of plasmon resonance at 267 nm. The obtained particle size of selenium nanospheres was 65.76 nm. They were maintained in a stable form for 5 months at 4 °C. Transmission electron microscopy (TEM) images demonstrated the presence of individual spherical nanoparticles. Fourier transform infrared spectroscopy (FT-IR) showed the interaction between COO extract and selenium, exhibiting good entrapment efficiency (87%). The elemental analysis of COO extract and GA-COO-SeNPs confirmed that NPs were obtained. The zebrafish were exposed to a high glucose concentration for two weeks, and type 2 diabetes and oxidative stress responses were induced. In diabetic zebrafish, treatment with NPs showed antilipidemic and hypoglycemic effects, high survivability, and reduced levels of glucose, reactive oxygen species (ROS), and lipids in the blood. This group this had a higher survivorship rate than the diabetic control. The results demonstrated that GA-Se-COO-NPs have high antidiabetic potential, most likely because of the synergic effects of phenolic compounds and Se nanoparticles.

Interval cytoredutive surgery and HIPEC in advanced ovarian cancer with small-bowel disease: results and reflections.

INTRODUCTION: Small-bowel involvement in patients with ovarian cancer has been strongly correlated with the possibility of cytoreduction and thus with survival. The main objective of this study was to evaluate the prognostic significance of small-bowel involvement in patients undergoing optimal-complete interval cytoreductive surgery (CRS) and Hyperthermic Intraperitoneal Chemotherapy (HIPEC). METHODS: We included a series of patients diagnosed with stage IIIC-IVA (pleural effusion) high-grade serous epithelial ovarian cancer and in whom CRS + HIPEC was indicated after neoadjuvant systemic chemotherapy (NACT). The study period extended from January 2008 to January 2020, with a minimum follow-up of 12 months from the inclusion of the last patient. A multivariate analysis using Cox regression allowed us to identify the variables that were independently related to disease-free survival. RESULTS: A total of 144 patients were selected, 13 (9%) of whom were excluded from the analysis, because their disease was considered unresectable. The study included a series of 131 patients with a median age of 62 years (34-79 years) and a median Peritoneal Cancer Index (PCI) calculated during surgery of 9 (1-35). The median PCI of bowel areas 9-12 (SB-PCI) was 3 (1-10). Performance of a CC-1 cytoreduction (HR: 1.93, 95% CI: 1.02-3.64, p = 0.042) and SB-PCI greater than 3 (HR: 2.25, 95%CI: 1.13-4.48, p = 0.21) were independent factors associated with shorter disease-free survival. CONCLUSION: Small-bowel involvement, even in patients with a macroscopically complete resection, showed a correlation with worse prognostic outcomes and could be considered as a variable in the postoperative management of these patients.

Optimization of ultrasonic-assisted extraction of polyphenols from the polyherbal formulation of Cinnamomum verum, Origanum majorana, and Origanum vulgare and their anti-diabetic capacity in zebrafish (Danio rerio).

The Cinnamomum verum (CV), Origanum majorana (CM), and Origanum vulgare (OV) have been used in traditional medicine in several regions of México for their anti-diabetic properties. In this study investigated the variables of ultrasound-assisted extraction for the polyphenolic compounds from the combination of these plants and explore their potential antidiabetic activities on glucose-induced-diabetic zebrafish. Determined the optimum conditions for ultrasonic-assisted extraction (UAE) to maximum recovery amounts of phenolic compounds from the extract of these plants. Polyphenols were detected in the extracts using HPLC-DAD-analysis. Extracts were evaluated on zebrafish exposed to high glucose concentration (110 mM) for two weeks. Results showed second-order polynomial mathematical models with a high coefficient of determination (R2 > 0.9564). Optimized extraction conditions for UAE from the combination of the 3 plants (COV) were as follows: 66.03%, ethanol, 28.87 min, and 21.51 mL/g for maximal flavonoids extraction. Used the same optimal extraction conditions for CV, CM, and OV. Results from LC-MS/MS indicated 9 polyphenolic compounds in CV, 12 in CM, and 6 in OV, the content of total polyphenols was 310.28, 90.42, and 126.74 mg GAE 100 g-1 dry weight, respectively. However, hyperglycemic fish showed an increase in cholesterol and triglyceride levels whereas extracts completely prevented these metabolic alterations. COV showed higher anti-diabetic ability than CV, CM, and OV, suggesting a synergistic effect between them. Our investigation developed a new herbal formulation of Cinnamomum verum; Origanum majorana; Origanum vulgare that has proven effective in animals with type 2 diabetes will form a new class of supplements to treat diabetic complications.

Concentrations of Salivary Cortisol in Victims of Intimate Partner Violence According to the CIRCORT Database.

This work analyzes the different levels of salivary cortisol in women from the southwest of Spain that were victims of intimate partner violence (IPV) with respect to a control group, assessing for the first time the different concentrations obtained in relation to a worldwide reference standard provided by the CIRCORT meta-global cortisol database. The clinical sample (N = 24) and the control group (N = 25) had an average of 39.12 years (SD = 12.31) and 39.52 years (SD = 11.74), respectively. Cortisol awakening response (CAR) was determined by defining the area under the curve (AUCi). There were no differences between the CAR data of the two populations F (1, 141) = 1.690, p = 0.196, but there was a highly significant difference in the three sampling days, where the clinical sample exceeded the cortisol levels of the CIRCORT database in the evening as compared to the control group (p = 0.004, p = 0.001 and p = 0.000). Salivary cortisol concentration samples taken in the evening were significantly higher than those standardized in the CIRCORT database, from the women victims of IPV as compared to the control group, showing its usefulness as an effective supportive tool for problems such as those triggered by IPV.

Unresectable GIST liver metastases and liver transplantation: A review and theoretical basis for a new indication.

BACKGROUND: Liver metastases from gastrointestinal stromal tumors (GIST) can be found synchronously to a primary tumor and in the medium/long term after resection of a high-risk GIST. In these cases, treatment with tyrosine kinase inhibitors like imatinib has provided good results, but drug resistance is common after two years of treatment. Liver resection of potentially resectable metastases can improve the results of medical treatment. In cases of unresectability, the role of liver transplantation (LT) has not been well-studied. MATERIALS AND METHODS: A review of the literature was undertaken from January 1995 to December 2020 following the PRISMA and AMSTAR guidelines. RESULTS: Fifteen cases were identified. In eight cases, the LT was carried out before 2002. Mutational status was only studied in seven cases. LT was performed in 12 cases with a deceased donor and in three cases with a living donor. After a mean follow-up of 52.4 months, overall survival was 86.6% with disease-free survival of 53.3% CONCLUSION: LT in the management of unresectable GIST metastases has rarely been performed. Although its application has a solid theoretical basis, its use understood as a radical extension of a standard resection can only be recommended within prospective studies by groups with considerable experience in both GIST and transplantation care.

Acute renal disease in patients with ovarian peritoneal carcinomatosis treated with cytoreduction and HIPEC: the influence of surgery and the cytostatic agent used.

BACKGROUND: The main objective of this study was to evaluate the differences between cisplatin and paclitaxel in the development of postoperative renal toxicity, using as a reference the RIFLE (Risk, Injury, Insufficiency, Loss, and End-stage renal function) and AKIN (Acute Kidney Injury Network) criteria in patients with primary or recurrent ovarian cancer with peritoneal dissemination treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC). METHODS: One hundred fifty-two patients who were treated between December 2007 and June 2017 were analyzed. RESULTS: Patients who received previous platinum-based chemotherapy had higher baseline creatinine levels than those who had not (p = 0.05). A total of 11 (7.2%) and 4 (2.6%) patients developed an acute renal dysfunction (ARD) during the postoperative period of cytoreduction and HIPEC according to the RIFLE and AKI criteria respectively. RIFLE detects a higher rate of ARD due to different parameters such as GFR (7.2% versus 2.6%, p = 0.016). Performing ostomy (p = 0.007; OR: 39.320; 95% CI = 2.74-56.13) and using of cisplatin during HIPEC treatment (p = 0.017; OR = 13.619; 95% IC = 1.600-25.95) were factors independently related to a higher rate of ARD. CONCLUSION: ARD has a multifactorial origin. Cisplatin was associated with the development of a higher rate of ARD than paclitaxel. Diagnosis of ARD did not correlate with worse survival figures.

Toxigenic Microcystis aeruginosa (Cyanobacteria) affects the population growth of two common green microalgae: Evidence of other allelopathic metabolites different to cyanotoxins.

Agriculture runoffs and discharge of wastewaters are the major causes of eutrophication. Although eutrophication could promote the thriving of any phytoplankter, harmful algal blooms (HABs) are dominated frequently by cyanobacteria. Currently, HABs dominated by the toxigenic cyanobacterium Microcystis aeruginosa in lakes and reservoirs are the main environmental concerns worldwide. This study aimed to determine how M. aeruginosa (Ma) modifies the population growth of Pseudokirchneriella subcapitata (Ps) and Ankistrodesmus falcatus (Af). Growth kinetics were determined for each species and in the combinations: Ps-Ma, Af-Ma, Af-Ps, and Ps-Af-Ma. At the end of experiments, photosynthetic pigments, phycobiliproteins, and microcystins were quantified. A logistic equation significantly described the growth trend for all of the tested species, enabling the identification of negative effects on early stages in the population growth of co-cultures with the cyanobacterium; in addition, the interaction effects on the growth rate and in the maximum attainable population density were determined. The biomasses of A. falcatus and P. subcapitata were significantly higher when cultured individually than in all of the combinations with the cyanobacterium. The concentrations of chlorophyll a and b, as well as carotenoids, were lower in combined cultures, but phycobiliprotein content in the cultures with M. aeruginosa was not significantly affected. Microcystis aeruginosa negatively affected the growth of the microalgae, but A. falcatus was significantly more inhibited than P. subcapitata; however, microcystin concentrations were significantly reduced in the co-cultures with microalgae. These results could help to explain the displacements of microalgae when cyanobacteria are present, giving rise to cyanobacterial blooms in eutrophic freshwaters.

Exposure to sublethal concentrations of the glyphosate-based herbicide Faena® increases sensitivity in the progeny of the American cladoceran Daphnia exilis (Herrick, 1895).

The use of herbicides has increased over the last decades. Glyphosate is the most widely used herbicide commercialized in more than 750 formulations. While information about glyphosate's toxicity on different non-target aquatic organisms has been vastly documented, we know little about the transgenerational effects in aquatic biota. This study determined the cross-generation effects produced by the glyphosate-based herbicide Faena® on the American cladoceran Daphnia exilis. Measured endpoints were survival, reproductive responses, metabolic biomarkers, and the size of neonates. D. exilis was exposed to glyphosate concentrations of 2.09, 2.49, and 3.15 (mg L-1) (as content in Faena®) during 21 days starting from neonates, at 25°C, 16:8 photoperiod, fed with 8 × 105 cells mL-1 of Pseudokirchneriella subcapitata. The LC50 was 4.22 mg L-1. Survival, accumulated progeny, and the number of clutches in the parental generation (P1) were significantly higher than those observed in the first generation (F1). Exposure to the herbicide completely inhibited reproduction in the F1. The size of the neonates varied among treatments and broods in P1; nevertheless, neonate size (body and total lengths, as well as body width) was significantly affected in F1. Toxic effects on the survival and reproduction of D. exilis were significantly increased in the F1 exposed to Faena®. Results warn about the augmented effect on progeny where parents were exposed to this herbicide. Multigenerational adverse effects could be expected in freshwater zooplankton exposed to Faena®. The frequently claimed low toxicity of glyphosate must be revised to control the indiscriminate use of this herbicide.

Anthropogenic contaminants in freshwater from the northern Antarctic Peninsula region.

This study aimed to evaluate the presence of ultraviolet filters (UV-Fs), benzotriazoles, pyrethroids and per- and polyfluoroalkyl substances (PFASs) in freshwater and wastewater from the northern Antarctic Peninsula region. All water samples analyzed contained UV-Fs residues and high concentrations were detected in anthropogenic impacted sites (< LOD up to 1300 ng/L). Likewise, benzotriazoles were detected in all water samples (< LOQ-920 ng/L). Regarding suspended particulate matter, almost all UV-Fs and all benzotriazoles were measured at concentrations ranging from < LOQ to 33 µg/g dry weight. Pyrethroids were also detected (< LOQ-250 ng/L) and their presence implies the existence of a gateway to the Antarctica Peninsula from other regions. The data confirmed the presence of PFASs (< LOD-7500 ng/L) in this area, in agreement with previous studies. In light of these results, extended monitoring in Antarctica should be carried out to perform a reliable environmental risk assessment leading to propose recommendations to minimize the anthropic impact.

A high-throughput assay for screening environmental pollutants and drugs impairing predator avoidance in Daphnia magna.

This study addresses short-term habituation of the escape response in the aquatic crustacean Daphnia magna evoked by sudden changes in light intensity, using a high-throughput system. Daphnia magna exhibits a marked phototactic behaviour and swim away from light to avoid predation by fish. Currently, there is no information available on the habituation of this phototactic response. The Daphnia photomotor response assay (DPRA) measures the distance moved after a sudden increase in light intensity. Using DPRA, it is possible to determine not only the magnitude of the phototactic response, but also its habituation after repetitive cycles of light and darkness. The progressive reduction observed in response to a series of light stimuli in the proposed assay meet the criteria for habituation. Most cholinergic and serotonergic modulators enhanced photomotor responses and reduced habituation. Dopaminergic and histaminergic modulators also reduced habituation, whereas diazepam was the only compound that increased habituation. Imidacloprid, apomorphine, diphenhydramine, diazepam, and memantine decreased photomotor responses. Thus, the DPRA was also predictive in assessing the effects of neuroactive and neurotoxic environmental contaminants such as selective serotonin reuptake inhibitors, diazepam, organophosphorous, and neonicotinoid pesticides. We conclude that the proposed DPRA may be an effective screening tool for compounds that can impair predation avoidance behaviour in aquatic organisms.

Seasonal changes in the bacterial community structure of three eutrophicated urban lakes in Mexico city, with emphasis on Microcystis spp.

Artificial urban lakes commonly have physicochemical conditions that contribute to rapid anthropogenic eutrophication and development of cyanobacterial blooms. Microcystis is the dominat genus in most freshwater bodies and is one of the main producter of microcystins. Using 454-pyrosequencing we characterized the bacterial community, with special emphasis on Microcystis, in three recreational urban lakes from Mexico City in both wet and dry seasons. We also evaluated some physicochemical parameters that might influence the presence of Microcystis blooms, and we associated the relative abundance of heterotrophic and autotrophic bacterial communities with their possible metabolic capacities. A total of 14 phyla, 18 classes, 39 orders, 53 families and 48 bacterial genera were identified in both seasons in the three urban lakes. Cyanobacteria had the highest relative abundance followed by Proteobacteria and Actinobacteria. Microcystis was the dominant taxon followed by Arthrospira, Planktothrix and Synechococcus. We also found heterotrophic bacteria associated with the blooms, such as Rhodobacter, Pseudomonas, Sphingomonas and, Porphyrobacter. The highest richness, diversity and dominance were registered in the bacterial community of the Virgilio Uribe Olympic Rowing-Canoeing Track in both seasons, and the lowest values were found in the Chapultepec Lake. The canonical correspondence analysis showed that dissolved oxygen and NO3-N concentrations might explain the presence of Microcystis blooms. The metabolic prediction indicated that these communities are involved in photosynthesis, oxidative phosphorylation, methane metabolism, carbon fixation, and nitrogen and sulfur metabolism. The lakes studied had a high prevalence of Microcystis, but average values of microcystins did not exceed the maximum permissible level established by the United States Environmental Protection Agency for recreational and cultural activities. The presence of cyanobacteria and microcystins at low to moderate concentrations in the three lakes could result in ecosystem disruption and increase animal and human health risks.

Multistressor negative effects on an experimental phytoplankton community. The case of glyphosate and one toxigenic cyanobacterium on Chlorophycean microalgae.

Aquatic ecosystems face serious pollution issues. Discharges of toxic substances and eutrophication may lead to changes in the phytoplankton community and foster cyanobacterial blooms. Glyphosate-based herbicides are chemical stressors of microalgae that may affect the structure of phytoplankton communities, and also stimulate the synthesis of cyanotoxins by cyanobacteria. The simultaneous presence of glyphosate and toxigenic cyanobacteria increases the stress on microalgae, jointly affecting their growth and development. This study evaluated the combined effect of a toxigenic cyanobacterium and glyphosate in the development of an experimental microalgal community. We studied the effect of Microcystis aeruginosa on the population growth of the microalgae Ankistrodesmus falcatus, Chlorella vulgaris, Pseudokirchneriella subcapitata, and Scenedesmus incrassatulus. We also evaluated the combined effect of sub-inhibitory glyphosate (Faena®) concentrations on the content of macromolecules and the enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), as well as on the concentration of TBARS. These effects were evaluated through the integrated biomarker response (IBR). In individual experiments, microalgae showed lower growth rates versus M. aeruginosa. In the mixed bioassays, both M. aeruginosa and microalgae showed reduced growth. IC50 values for Faena® ranged from 1.022 to 2.702 mg L-1. In the microalgae + cyanobacteria bioassays, the herbicide lowered the growth rates of microalgae but stimulated the proliferation of M. aeruginosa. The joint action of both stressors affected growth rate and population dynamics, macromolecule content, and led to increased CAT and GPx levels. Faena® influenced growth rate and caused oxidative stress. On the other hand, the herbicide stimulated the synthesis of cyanotoxins, which further affected microalgal development. The experimental community was not only affected by the herbicide, but the mixed culture with cyanobacteria magnified the effects of chemical stress. These results illustrate the potential damage to phytoplankton expected in anthropically eutrophic water bodies that are also polluted by glyphosate.