scholarly journals Synergistic Effect of Chloroquine and Copper to the Euryhaline Rotifer Proales Similis

2021 ◽  
Author(s):  
Uriel Arreguin Rebolledo ◽  
Roberto Rico-Martínez ◽  
Rocío Fernández ◽  
Federico Páez-Osuna
Keyword(s):  
Chronic Toxicity ◽  
Synergistic Effects ◽  
Emerging Pollutants ◽  
Aquatic Systems ◽  
Population Increase ◽  
Potential Hazard ◽  
Zooplankton Species ◽  
Test Species ◽  
Almost All ◽  
Potential Test

Abstract Chloroquine (CQ) has been widely used for many years against malaria and various viral diseases. Its important use and high potential to being persistent make it of particular concern for ecotoxicological studies. Here, we evaluated the toxicity of CQ alone and in combination with copper (Cu) to the euryhaline rotifer Proales similis. All experiments were carried out using chronic toxicity reproductive five‐day tests and an application factor (AF) of 0.05, 0.1, 0.3 and 0.5 by multiplying the 24-h LC50 values of CQ (4250 µg/L) and Cu (68 µg/L). The rate of population increase (r, d-1) ranged from 0.50 to 52 (controls); 0.19 to 0.39 (CQ); 0.09 to 0.42 (Cu); and -0.03 to 0.29 (CQ-Cu) and decreased significantly as the concentration of both chemicals in the medium increased. Almost all tested mixtures induced synergistic effects, mainly as the AF increased. We found that the presence of Cu intensifies the vulnerability of organisms to CQ and vice versa. These results stress the potential hazard that these combined chemicals may have on the aquatic systems. This research suggests that P. similis is sensitive to CQ as other standardized zooplankton species and may serve as a potential test species in the risk assessment of emerging pollutants in marine environments.

scholarly journals Assessment of the potential of a reduced dose of dimethyl disulfide plus metham sodium on soilborne pests and cucumber growth

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Liangang Mao ◽  
Hongyun Jiang ◽  
Lan Zhang ◽  
Yanning Zhang ◽  
Muhammad Umair Sial ◽  
...  
Keyword(s):  
Synergistic Effects ◽  
Standard Dose ◽  
Dimethyl Disulfide ◽  
Field Trials ◽  
Economic Benefits ◽  
Soil Fumigation ◽  
Dose Treatment ◽  
Reduced Dose ◽  
Almost All ◽  
Metham Sodium

AbstractMethyl bromide (MB), a dominant ozone-depleting substance, is scheduled to be completely phased out for soil fumigation by December 30th 2018, in China. The combined effects of dimethyl disulfide (DMDS) plus metham sodium (MNa) were assessed in controlling soilborne pests for soil fumigation. A study was designed in laboratory for the evaluation of the efficacy of DMDS + MNa to control major soilborne pests. At the same time, two trials were conducted in cucumber field located in Tongzhou (in 2012) and Shunyi (in 2013), respectively, in order to assess the potential of DMDS + MNa in controlling soilborne pests. Laboratory studies disclosed positive synergistic effects of almost all four used combinations on Meloidogyne spp., Fusarium spp., Phytophthora spp., Abutilon theophrasti and Digitaria sanguinalis. Field trials found that DMDS + MNa (30 + 21 g a. i. m−2), both at a 50% reduced dose, effectively suppressed Meloidogyne spp. with a low root galling index (2.1% and 11.7%), significantly reduced the levels of Phytophthora and Fusarium spp. with a low root disease index (7.5% and 15.8%), gave very high cucumber yields (6.75 kg m−2 and 10.03 kg m−2), and increased income for cucumber growers with the highest economic benefits (20.91 ¥ m−2 and 23.58 ¥ m−2). The combination treatment provided similar results as MB standard dose treatment (40 g a. i. m−2) or DMDS standard dose treatment (60 g a. i. m−2) in pest control and yield, but was more effective than MNa standard dose treatment (42 g a. i. m−2). Usage of all chemical treatments gave better significant results than the untreated group of control. Considering the economic benefits, the DMDS plus MNa combination (30 + 21 g a. i. m−2) could be used for soil fumigation in cucumber production in China.

scholarly journals Shape and size of the arenas affect amphipod behaviours: implications for ecotoxicology

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5271 ◽  
Author(s):  
Shanelle A. Kohler ◽  
Matthew O. Parker ◽  
Alex T. Ford
Keyword(s):  
False Negative ◽  
Careful Consideration ◽  
Negative Effects ◽  
Mean Velocity ◽  
Major Drawback ◽  
Test Species ◽  
Amphipod Crustacean ◽  
Almost All ◽  
Invertebrate Models ◽  
A Current

The use of behaviour in ecotoxicology is expanding, however the lack of standardisation and validation of these assays currently presents a major drawback in moving forward in the development of behavioural assays. Furthermore, there is a current paucity of control data on test species, particularly invertebrate models. In this study we assessed a range of behaviours associated with spatial distribution and locomotion in relation to arena size and shape in two species of amphipod crustacean (Echinogammarus marinus and Gammarus pulex). Arena shape had significant effects on almost all behavioural parameters analysed. Increasing arena size resulted in an increased mean velocity and activity plus increased proportional use of the central zones. These results indicate that ‘ceiling effects’ may occur in some ecotoxicological studies resulting in potentially ‘false’ negative effects if careful consideration is not paid to experimental design. Differences in behaviours were observed between the two species of amphipod. For example, G. pulex spend approximately five times (∼20%) more of the available time crossing the central zones of the arenas compared to E. marinus (∼4%) which could have implications on assessing anxiolytic behaviours. The results of this study highlight several behaviours with potential for use in behavioural ecotoxicology with crustaceans but also underscore the need for careful consideration when designing these behavioural assays.

scholarly journals An overview of E-waste, its management practices and legislations in present Indian context

2021 ◽  
Vol 13 (1) ◽  
pp. 34-41
Author(s):  
Rajeev Rajput ◽  
Rinki ◽  
Nidhi Ahuja Nigam
Keyword(s):  
Coming Out ◽  
Urban Areas ◽  
Management Practices ◽  
Electronic Waste ◽  
Electrical Equipment ◽  
Population Increase ◽  
Indian Context ◽  
Waste Production ◽  
Almost All ◽  
Very High

E-waste coming out from the electronic sector of the entire world is harming the world's environment. There has been a pattern of a substantial increase in the production of E-waste worldwide. This is as a consequence of population increase, industrialization, urbanization and economic activity. Since the last decade, the rate of consumerism has been found to be very high due to higher economic growth, which has resulted in increased E-waste production. Almost all countries are recycling more and more E-waste, but a million tonnes of E-waste still coming out. Experts believe that the rise of E-waste is due to our rapidly changing lifestyles. We have started adopting new electronic devices coming into the market, trying to make life more convenient. In  India, electronic waste is growing at 10% per annum.  The trend of urbanization has played a significant role in the enhancement of E-waste generation. The population living in urban areas was 27.67% in 2000, 38.03% in 2018, and is expected to reach approximately 42% in 2025. As the population increases, the amount of E-waste will also rise to an alarming situation. This review paper provides the present scenario of E-waste and its management practices and legislation in the present Indian context. This would help all the stakeholders involved in the production of electrical equipment to gain better understanding of E-waste.

scholarly journals Diversity of resident plant communities could weaken their allelopathic resistance against alien and native invaders

2021 ◽  
Author(s):  
Ling Yuan ◽  
Junmin Li ◽  
Mark van Kleunen
Keyword(s):  
Plant Communities ◽  
Single Species ◽  
Resident Species ◽  
Test Species ◽  
Diverse Communities ◽  
Allelopathic Effects ◽  
Almost All ◽  
Germination Experiment ◽  
Germinated Seeds

AbstractElton’s classic diversity-invasibility hypothesis posits that diversity of resident communities increases resistance against invaders. We tested whether the diversity-invasibility relationsip might be mediated by allelopathic effects of the resident species. In a large germination experiment, we exposed seeds of six alien and six native test species to leachates of one, three, six or twelve species. The leachates tended to slightly delay germination, and almost all single-species leachates reduced the proportion of germinated seeds. Nevertheless, the overall effect of the plant leachate mixtures on the proportion of germinated seeds was not significant. This was because a higher diversity of the leachates increased the proportion of germinated seeds, particularly for native test species. Among the six alien test species, it was only the most invasive one that benefited from increased diversity of the leachates, just like the natives did. Overall, our findings suggest that allelopathy of diverse communities does not provide resistance but could actually facilitate the germination of invaders.

scholarly journals Colony strength and queen replacement in Melipona marginata (Apidae: Meliponini)

2005 ◽  
Vol 65 (3) ◽  
pp. 469-476 ◽  
Author(s):  
A. de M. P. Kleinert
Keyword(s):  
Oviposition Rate ◽  
Population Increase ◽  
Queen Replacement ◽  
Melipona Marginata ◽  
Almost All ◽  
Virgin Queens

Physogastric queens of Melipona marginata were removed from their colonies in order to verify the acceptance of a new queen by workers. Colony strength was evaluated according to queen oviposition rate and comb diameters. Replacement was observed seven times. Its occurrence and speed related positively to colony strength, independently of queen's age. In weak colonies, queen replacement was observed only once, following colony population increase that occurred after introduction of combs from another colony. Worker oviposition after queen removal was observed three times: in a strong colony with virgin queens and males, and in two of the weak colonies. In the first two or three days of new queen oviposition, during which most of the eggs were eaten by the queen, worker oviposition preceded almost all provisioning and oviposition processes (POPs). After this period, worker oviposition decreased until it reached around 25% of the POPs. Daily oviposition rate of young queens decreased or was even interrupted by hatching of their first brood.

scholarly journals Serum Level of Antibody against Benzo[a]pyrene-7,8-diol-9,10-epoxide-DNA Adducts in People Dermally Exposed to PAHs

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Lenka Borska ◽  
Ctirad Andrys ◽  
Jan Krejsek ◽  
Vladimir Palicka ◽  
Marcela Chmelarova ◽  
...  
Keyword(s):  
Serum Level ◽  
Dna Adducts ◽  
Elevated Level ◽  
Total Duration ◽  
Potential Hazard ◽  
Polycyclic Aromatic ◽  
Pasi Score ◽  
General Goal ◽  
Almost All ◽  
Different Levels

Some specific antibodies indicate the presence of antigenic structures on DNA (DNA adducts) that can play an important role in the process of mutagenesis and/or carcinogenesis. They indicate the presence of increased genotoxic potential (hazard) prior to the formation of disease (primary prevention). The present study was focused on the serum level of benzo[a]pyrene 7,8-diol-9,10-epoxide-DNA adducts antibodies (anti-BPDE-DNA) in psoriatic patients(n=55)dermally exposed to different levels of polycyclic aromatic hydrocarbons (PAHs). The general goal of the study was to contribute to better understanding of the value of the assumed biomarker (anti-BPDE-DNA) for evaluation of the organism's answer to genotoxic exposure to PAHs. Elevated level of exposure to PAHs resulted in the increased level of anti-BPDE-DNA. However, almost all levels of anti-BPDE-DNA ranged within the field of low values. Both variants of GT (CCT-3% and CCT-5%) induced higher expression of anti-BPDE-DNA in the group of nonsmokers. Significant relations between the level of anti-BPDE-DNA and PASI score, total duration of the therapy, or time of UVR exposure were not found. Further studies are needed to reduce interpretation uncertainty of this promising bioindicator.

Correlations Between Daphnia magna and Fathead Minnow (Pimephales promelas) Chronic Toxicity Values for Several Classes of Test Substances

1979 ◽  
Vol 36 (4) ◽  
pp. 411-421 ◽  
Author(s):  
A. W. Maki
Keyword(s):  
Daphnia Magna ◽  
Chronic Toxicity ◽  
Polychlorinated Biphenyl ◽  
Pearson Correlation ◽  
Pimephales Promelas ◽  
Toxicity Tests ◽  
Toxicity Data ◽  
High Fecundity ◽  
Test Species ◽  
Toxicant Concentration

Chronic toxicity values were developed for Daphnia magna with six surfactants and a detergent builder, each selected on the basis of previously existing chronic fish test data. Predictive correlations were examined for testing end points between 21-d Daphnia chronics and 1-yr fish chronics to provide a short-term alternative chronic test species while developing toxicity data for an intermediate trophic level species. For the detergent materials tested, a strong correlation (r = 0.98) exists between Daphnia and fish no-effect concentrations. A replacement term, NOEC (no observed effect concentration), is suggested to clarify interpretive ambiguities associated with the definition of the MATC (maximum acceptable toxicant concentration) value. Additional chronic toxicity data from the current literature for these two test species and several test substances representing metals, polychlorinated biphenyl isomers, and pesticide formulations were similarly compared. A correlation analysis demonstrated an overall Pearson correlation coefficient of 0.79 for these data. Although significant outliers were evident from this correlation, these differences may be due primarily to differences in modes of toxic action of these test substances. The relatively short life cycle and 21-d duration of the test, small water volumes, ease in handling, high fecundity, and good correlation of 21-d chronic data with chronic fish toxicity data make Daphnia chronic tests an attractive alternative to the conduct of longer term fish tests. Key words: Daphnia, Pimephales promelas, toxicity tests, chronic, mortality, surfactants, metals, pesticides

scholarly journals Synergistic Antibacterial Effects of Meropenem in Combination with Aminoglycosides against Carbapenem-Resistant Escherichia coli Harboring blaNDM-1 and blaNDM-5

Antibiotics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1023
Author(s):  
Pawarisa Terbtothakun ◽  
Ozioma Forstinus Nwabor ◽  
Thanyaluck Siriyong ◽  
Supayang P. Voravuthikunchai ◽  
Sarunyou Chusri
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Agents ◽  
Synergistic Effects ◽  
Treatment Options ◽  
Molecular Characteristics ◽  
Carbapenem Resistant ◽  
Aminoglycoside Therapy ◽  
Checkerboard Assay ◽  
Almost All ◽  
Time Kill

Infections due to carbapenem-resistant Escherichia coli (CREC) are problematic due to limitation in treatment options. Combination therapies of existing antimicrobial agents have become a reliable strategy to control these infections. In this study, the synergistic effects of meropenem in combination with aminoglycosides were assessed by checkerboard and time-kill assays. Of the 35 isolates, 19 isolates (54.3%) were resistant to carbapenems (imipenem and meropenem) with the MIC ranges from 16 to 128 µg/mL. These isolates were resistant to almost all antibiotic classes. Molecular characteristics revealed co-harboring of carbapenemase (blaNDM-1, blaNDM-5 and blaOXA-48) and extended-spectrum β-lactamases (ESBL) genes (blaCTX-M, blaSHV and blaTEM). The checkerboard assay displayed synergistic effects of meropenem and several aminoglycosides against most CREC isolates. Time-kill assays further demonstrated strong synergistic effects of meropenem in combination with either amikacin, gentamicin, kanamycin, streptomycin, and tobramycin. The results suggested that meropenem in combination with aminoglycoside therapy might be an efficient optional treatment for infections cause by CREC.

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