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Bioassay method was used to study the toxicity of natural water, sampled in the Moskva R. at sites with different level of anthropogenic impact in all hydrological seasons of the year. The effect of natural water chemistry on the sensitivity to a model toxicant (potassium dichromate) was evaluated for three laboratory test objects—unicellular algae Scenedesmus quadricauda (Turh.) Breb., crustaceans Daphnia magna Straus, and fish Poecilia reticulata Peters. The sensitivity of test objects was assessed by the values of median lethal (for daphnia and fish) and median effective (for algae) concentrations of the model toxicant, obtained with the use of the water samples as media for the preparation of test solutions of the toxicant. It was shown that, under the conditions of complex anthropogenic pollution, including an increase in TDS, the sensitivity of Daphnia magna and Poecilia reticulata to the standard toxicant was generally within the standard range for each test object, while in the case of Scenedesmus quadricauda, almost all obtained values of median effective concentrations were above the standard range (the sensitivity was lower). Statistically significant correlation was found between the median lethal concentration for Daphnia magna and a complex of interrelated hydrochemical characteristics, including TDS. The observed differences in the changes in the sensitivity of test-objects are presumably due to changes in water hardness. It is noted that the decrease in test object sensitivity under the effect of changes in water ionic composition can lead to overestimation of the maximal permissible concentrations, which are established with the use of natural water for water bodies, taking into account their natural features. The obtained results can be used in the formation of methodological approaches to regional standardization.

The effect of Ocean Acidification (OA) on marine biota is quasi-predictable at best. While perturbation studies, in the form of incubations under elevated pCO(2), reveal sensitivities and responses of individual species, one missing link in the OA story results from a chronic lack of pH data specific to a given species' natural habitat. Here, we present a compilation of continuous, high-resolution time series of upper ocean pH, collected using autonomous sensors, over a variety of ecosystems ranging from polar to tropical, open-ocean to coastal, kelp forest to coral reef. These observations reveal a continuum of month-long pH variability with standard deviations from 0.004 to 0.277 and ranges spanning 0.024 to 1.430 pH units. The nature of the observed variability was also highly site-dependent, with characteristic diel, semi-diurnal, and stochastic patterns of varying amplitudes. These biome-specific pH signatures disclose current levels of exposure to both high and low dissolved CO(2), often demonstrating that resident organisms are already experiencing pH regimes that are not predicted until 2100. Our data provide a first step toward crystallizing the biophysical link between environmental history of pH exposure and physiological resilience of marine organisms to fluctuations in seawater CO(2). Knowledge of this spatial and temporal variation in seawater chemistry allows us to improve the design of OA experiments: we can test organisms with a priori expectations of their tolerance guardrails, based on their natural range of exposure. Such hypothesis-testing will provide a deeper understanding of the effects of OA. Both intuitively simple to understand and powerfully informative, these and similar comparative time series can help guide management efforts to identify areas of marine habitat that can serve as refugia to acidification as well as areas that are particularly vulnerable to future ocean change.

Biological organisms, used as test objects in pollution tests may be as good, or even more so, in detecting soil contamination, than chemical analyses. In this study, we used five bioassay methods, together chemical and physical-chemical tests, for comprehensive environmental assessment of contaminated soils located at the industrial waste storage sites in North-West Russia. Examined soils have been contaminated with various toxic pollutants at various times in the past. The level of contamination by Hg, Pb, Cd, Zn, Со, As, Cr, Cu, Mn, V, and As in studied soils varied depending on a site type. The concentrations of these elements were 20 to 43 times higher than the regional geochemical baseline at all sites. The organic pollutants (3,4-benzo(a)pyrene and polychlorinated biphenyls) were found at some sites. Ecotoxicological studies were carried out using test organisms from different taxonomic groups: ciliates Paramecium caudatum Ehrenberg, green algae Scenedesmus quadricauda (Turp.) Brebisson, seeds of common oat Avena sativa L.,wheat Triticum aestivum L., and a natural community of microorganisms. All the employed bioassays revealed some of the aspects of contamination, supported or supplemented each other’s estimates, and gave excellent performance at the sampling sites.

Background and aim To assess the detection rates of Helicobacter pylori colonization in the gastric cardia with two commercial kits of rapid urease test: 5 min UFT300 and 24 h CLO test in H. pylori‐infected patients. Methods Eighty consecutive dyspeptic patients with confirmed H. pylori infection (serology and 13C‐urea breath test) were prospectively studied. During endoscopy, tissue samples using separate biopsy forceps from the cardia were taken for the UFT300 and CLO tests. The results of the UFT300 were read at 5 and 30 min, and those of the CLO test were read at 24 h. Results Of 80 enrolled patients, 17 (21.3%) and 44 (55%) had positive findings with the UFT300 at 5 and 30 min, respectively, while 72 (90%) had positive findings with the CLO test at 24 h. The CLO test is significantly more sensitive than the UFT300 in evaluating H. pylori status in the cardia. On comparing patients with and without carditis, the detection rates of the CLO test were similar (91.1% vs 88.6%; P = 0.724), and the rates of the UFT300 were also similar at 5 and 30 min. Conclusions The rate of H. pylori colonization in the gastric cardia was 90% in H. pylori‐infected patients detected with the CLO test. Although the UFT300 provides a more rapid reading of H. pylori status, the diagnostic yield of the CLO test is much higher than that of the UFT300. However, a positive result of the UFT300 may indicate a higher bacterial load in the cardia, which warrants a more effective therapeutic strategy. The rate of H. pylori colonization in the gastric cardia detected with the CLO test is fairly high for patients with carditis (91.1%). Although the UFT300 provides a more rapid reading of H. pylori status, the diagnostic yield of the CLO test is much higher than that of the UFT300. However, a positive result with the UFT300 may indicate a higher bacterial load in the cardia, and a more effective therapeutic strategy should be considered.

Actinomycetes are Gram-positive, facultative anaerobic fungus-like filamentous bacteria which remain on the top of the natural antibiotic producers. Due to the climatic and geographical diversity of Nepal, a wide range of microorganisms with potent source of antimicrobials are available. The objective of this study was to isolate, identify, and screen the potential antimicrobial-producing actinomycetes from soils covering different altitude range of Nepal. Forty-one isolates of actinomycetes were isolated from 11 soil samples collected from different locations in Nepal with altitude ranging from 1500 to 4380 meters. The isolates were identified on the basis of morphological study, different sugar utilization, protein utilization, and hydrolysis tests. They were also characterized on the basis of temperature and pH. Primary screening for antimicrobial activity was carried out against several test organisms: Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATCC 700603), and Pseudomonas aeruginosa (ATCC 27853) by the perpendicular streaking method, and secondary screening was carried out by the agar well diffusion method using ethyl acetate for solvent extraction. 70.7% of the isolates were identified as Streptomyces spp., 19.5% as Nocardia spp., and 9.5% as Micromonospora spp. 43.34% of actinomycete isolates was found to be potent antimicrobial producers from the primary screening among which 46.34% were effective against Gram-positive and 12.19% against Gram-negative test organisms. Isolate C7 (Micromonospora spp.) showed the best broad-spectrum antimicrobial activity during secondary screening. A total of 11 different types of pigments were observed to be produced by different isolates, of which, the yellow pigment was the most prominent. The association between elevation, pH, and pigment with the antimicrobial production was found to be insignificant. This finding can be of importance for further investigation towards obtaining broad-spectrum antibiotics for therapeutic purpose.

BackgroundThe high production volume of engineered nanomaterials (ENMs) may lead to high pressure on the environment, and a scientific assessment of ENMs that bioaccumulate in organisms and biomagnify in the food web is necessary. Within the regulation of chemicals in several jurisdictions, such as the European regulation REACH, the bioconcentration factor is the standard endpoint. The bioconcentration factor is mostly determined by flow-through fish tests. However, nanomaterials tend to agglomerate, which may lead to sedimentation in aquatic environments. The bioavailability of the tested nanomaterials may be thus impaired for pelagic species, including fish, in comparison to benthic or filtrating species. Several risk assessment regulations allow the usage of data gained during tests using invertebrates and such data may allow a waiver of further tests using vertebrates. The aim of this study was to elucidate the potential of different freshwater invertebrate species to be used in laboratory bioaccumulation studies on ENMs and to give some guidance for the use of bioaccumulation endpoints derived from studies using aquatic invertebrate species in the risk assessment process for ENMs.ResultsThe existing literature related to the testing of nanomaterial bioaccumulation with freshwater invertebrates was screened and reviewed to find suitable test species with regard to their ecology and physiology, as well as laboratory test systems allowing to investigate the bioavailability/bioaccumulation of nanomaterials with the respective species. Bivalvia, gastropoda, isopoda, amphipoda, and branchiopoda were reviewed and their suitability for bioaccumulation testing was assessed. Amphipods and bivalves represent worst-case scenarios and show clear advantages to be used as test organisms. However, only amphipods allow the examination of two clearly independent exposure pathways (water and diet).ConclusionAmphipods are suitable test organisms for bioaccumulation testing of ENMs. The results from amphipod bioconcentration and biomagnification tests can be included in a tiered assessment suggested at the end of this study allowing a clear grading of the tested nanomaterials as “bioaccumulative” or “non bioaccumulative.” Due to the worst-case scenario of the amphipod test, this approach may allow a waiver of further vertebrate tests.

Metal oxides comprise a large group of chemicals used in water treatment to adsorb organic pollutants. The ability of titanium dioxide (TiO2) and iron (III) oxide (Fe2O3) to reduce the chronic toxicity of (phenolic) C6H6(OH)2 isomers, namely hydroquinone (HQ) and catechol (CAT) to Ceriodaphnia dubia and Pimephales promelas (less than 24 h-old) were investigated. The toxic endpoints following metal oxide treatment were compared to endpoints of untreated CAT and HQ. In chronic toxicity testing, HQ resulted in greater toxicity than CAT for both test organisms; the median lethal concentrations (LC50) for CAT were 3.66 to 12.36 mg.L−1 for C. dubia and P. promelas, respectively, while LC50 for HQ were 0.07 to 0.05 mg.L−1, respectively. Although both treated solutions presented lower toxic endpoints than those in the untreated solutions, Fe2O3 had a better potential to reduce the toxic effects of CAT and HQ than TiO2.

To compare the microbicidal activity of low-temperature sterilization technologies (vaporized hydrogen peroxide [VHP], ethylene oxide [ETO], and hydrogen peroxide gas plasma [HPGP]) to steam sterilization in the presence of salt and serum to simulate inadequate precleaning. Test carriers were inoculated with Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, vancomycin-resistant Enterococcus, Mycobacterium terrae, Bacillus atrophaeus spores, Geobacillus stearothermophilus spores, or Clostridiodes difficile spores in the presence of salt and serum and then subjected to 4 sterilization technologies: steam, ETO, VHP and HPGP. Steam, ETO, and HPGP sterilization techniques were capable of inactivating the test organisms on stainless steel carriers with a failure rate of 0% (0 of 220), 1.9% (6 of 310), and 1.9% (5 of 270), respectively. The failure rate for VHP was 76.3% (206 of 270). Steam sterilization is the most effective and had the largest margin of safety, followed by ETO and HPGP, but VHP showed much less efficacy.

The active herbicide ingredient glyphosate [ N -(phosphonomethyl)glycine] is frequently detected as a contaminant in groundwater and surface waters. This study investigated effects of UV-A (365 nm), UV-B (302 nm) and UV-C (254 nm) irradiation of glyphosate in water on photolysis and toxicity to aquatic organisms from different trophic levels. A test battery with bacteria (Bacillus subtilis, Aliivibrio fischeri) , a green microalga ( Raphidocelis subcapitata), and a crustacean (Daphnia magna) was used to assess biological effect of glyphosate and bioactive transformation products before and after UV irradiation (4.7–70 J/cm 2 ). UV-C irradiation at 20 J/cm 2 resulted in a 2–23-fold decrease in toxicity of glyphosate to aquatic test organisms. UV-B irradiation at 70 J/cm 2 caused a twofold decrease whereas UV-A did not affect glyphosate toxicity at doses ≤ 70 J/cm 2 . UV-C irradiation of glyphosate in drinking water and groundwater with naturally occurring organic and inorganic constituents showed comparable or greater reduction in toxicity compared to irradiation in deionized water. High-resolution mass spectrometry analyses of samples after UV-C irradiation showed > 90% decreases in glyphosate concentrations and the presence of multiple transformation products. The study suggests that UV mediated indirect photolysis can decrease concentrations of glyphosate and generate less toxic products with decreased overall toxicity to aquatic organisms.

Background The antimicrobial resistance of clinical, environmental and control strains of the WHO “Priority 1: Critical group” organisms, Acinetobacter baumannii , Escherichia coli , Klebsiella pneumoniae and Pseudomonas aeruginosa to various classes of antibiotics, colistin and surfactin (biosurfactant) was determined. Methods Acinetobacter baumannii was isolated from environmental samples and antibiotic resistance profiling was performed to classify the test organisms [ A. baumannii ( n  = 6), P. aeruginosa ( n  = 5), E. coli ( n  = 7) and K. pneumoniae ( n  = 7)] as multidrug resistant (MDR) or extreme drug resistant (XDR). All the bacterial isolates ( n  = 25) were screened for colistin resistance and the mobilised colistin resistance ( mcr ) genes. Biosurfactants produced by Bacillus amyloliquefaciens ST34 were solvent extracted and characterised using ultra-performance liquid chromatography (UPLC) coupled to electrospray ionisation mass spectrometry (ESI–MS). The susceptibility of strains, exhibiting antibiotic and colistin resistance, to the crude surfactin extract (cell-free supernatant) was then determined. Results Antibiotic resistance profiling classified four A. baumannii (67%) , one K. pneumoniae (15%) and one P. aeruginosa (20%) isolate as XDR, with one E. coli (15%) and three K. pneumoniae (43%) strains classified as MDR. Many of the isolates [ A. baumannii (25%), E. coli (80%), K. pneumoniae (100%) and P. aeruginosa (100%)] exhibited colistin resistance [minimum inhibitory concentrations (MICs) ≥ 4 mg/L]; however, only one E. coli strain isolated from a clinical environment harboured the mcr-1 gene. UPLC-MS analysis then indicated that the B. amyloliquefaciens ST34 produced C 13–16 surfactin analogues, which were identified as Srf1 to Srf5. The crude surfactin extract (10.00 mg/mL) retained antimicrobial activity (100%) against the MDR, XDR and colistin resistant A. baumannii , P. aeruginosa , E. coli and K. pneumoniae strains. Conclusion Clinical, environmental and control strains of A. baumannii , P. aeruginosa , E. coli and K. pneumoniae exhibiting MDR and XDR profiles and colistin resistance, were susceptible to surfactin analogues, confirming that this lipopeptide shows promise for application in clinical settings.