Effects of triclosan on gonadal differentiation and development in the frog Pelophylax nigromaculatus

Advancements in nanomaterial-based aptasensors for the detection of emerging organic pollutants in environmental and biological samples

The combination of nanomaterials (NMs) and aptamers into aptasensors enables highly specific and sensitive detection of diverse pollutants. The great potential of aptasensors is recognized for the detection of diverse emerging organic pollutants (EOPs) in different environmental and biological matrices. In addition to high sensitivity and selectivity, NM-based aptasensors have many other advantages such as portability, miniaturization, facile use, and affordability. This work showcases the recent advances achieved in the design and fabrication of NM-based aptasensors for monitoring EOPs (e.g., hormones, phenolic contaminants, pesticides, and pharmaceuticals). On the basis of their sensing mechanisms, the covered aptasensing systems are classified as electrochemical, colorimetric, PEC, fluorescence, SERS, and ECL. Special attention has been paid to the fabrication processes, analytical achievements, and sensing mechanisms of NM-based aptasensors. Further, the practical utility of aptasensing approaches has also been assessed based on their basic performance metrics (e.g., detection limits, sensing ranges, and response times).

Phenotypic Plasticity in Juvenile Frogs That Experienced Predation Pressure as Tadpoles Does Not Alter Their Locomotory Performance

Anuran species can respond to environmental changes via phenotypic plasticity, which can also result in ecological impacts across the life history of such species. We investigated the effects of predation pressure (i.e., the non-consumption effect) from the dragonfly larva (Anax parthenope) on the phenotypical change of tadpoles into juvenile frogs (specifically the black-spotted pond frog, Pelophylax nigromaculatus), and also analyzed the impact of morphological changes on locomotory performance after metamorphosis. The experiments on predator impact were conducted in the laboratory. Body length, weight, development timing, and metamorphosis timing in the presence of dragonfly nymphs were measured in both tadpoles and juvenile frogs. The body and tail shapes of the tadpoles, as well as the skeletal shape of the juvenile frogs, were analyzed using landmark-based geometric morphometrics. Furthermore, the locomotory performance of the juvenile frogs was tested by measuring their jumping and swimming speeds. Tadpoles that had grown with predators possessed smaller bodies, deeper tail fins, and slower development rates, and they waited longer periods of time before commencing metamorphosis. Having said this, however, the effect of predator cues on the body length and weight of juvenile frogs was not found to be significant. These juvenile frogs possessed longer limbs and narrower skulls, with subtle morphological changes in the pelvis and ilium, but there was no subsequent difference in their swimming and jumping speeds. Our results showed that the changes in anatomical traits that can affect locomotor performance are so subtle that they do not affect the jumping or swimming speeds. Therefore, we support the view that these morphological changes are thus by-products of an altered tadpole period, rather than an adaptive response to predator-escape ability or to post-metamorphosis life history. On the other hand, delayed metamorphosis, without an increase in body size, may still be disadvantageous to the reproduction, growth, and survival of frogs in their life history following metamorphosis.

Prevalence of organic micropollutants in the Yamuna River, Delhi, India: seasonal variations and governing factors

This work primarily emphases on evaluating the prevalence of organic micropollutants (OMPs) in the perennial Yamuna River (YR) that flow through the national capital of India, Delhi. Sixteen sampling campaigns (non-monsoon, n = 9; monsoon n = 7) were organized to understand the seasonal variations with special emphasis on monsoon. We have found fifty-five OMPs in the monsoon; while forty-seven were detected in non-monsoon. Fifty-seven screened and quantified OMPs in the most polluted stretch of River Yamuna included the pharmaceutically active compounds, pesticides, endocrine-disrupting chemicals, phthalates, personal care products, fatty acids, food additives, hormones, and trace organics present in hospital wastes. During monsoon months, compounds for which concentrations exceeded 50 μg/L were: adenine (64.6 μg/L), diethyl phthalate (62.9 μg/L), and octamethyltrisiloxane (56.9 μg/L); and the same for non-monsoon months was only for 1-dodecanethiol (52.3 μg/L). The average concentration of OMPs in non-monsoon months indicate PhACs>PCPs>Pesticides>Fatty acids>Hospital waste>Hormones>Pesticides>EDCs. In monsoon months due to surface runoff and high volume of untreated wastewater discharges few more OMPs concentrations were detected which mainly includes PhACs (clofibric acid, diclofenac sodium, gemfibrozil, ketoprofen), pesticides (aldrin, metribuzin, atrazine, simazine). Due to dilution effect in the monsoon months, average concentrations of 3-acetamido-5-bromobenzoic acid (PhACs) was reduced from 45.22 μg/L to 14.07 μg/L, whereas some EDCs such as 2,4- Di-tert-amylphenol, 3,5- di-tert-butyl-4-hydroxybenzyl alcohol, Triphenylphosphine oxide, Benzophenone were found in much higher concentrations in the monsoon months. Octamethyltrisiloxane (PCPs) was detected 50 times higher in concentration in the monsoon months. Interestingly, the concentration of about 50 % of the OMPs was more in the monsoon samples than in non-monsoon samples which is contrary to the general understanding that monsoon-induced dilution lowers the concentrations of OMPs. In RY water higher magnitude of diclofenac sodium, ibuprofen, ketoprofen, and clofibric acid was found than Europe and North America rivers. Hormones such as estriol and estrone in RY water are found 70 to 100 times higher than the maximum reported concentrations in the US streams. Finally, various OMPs responded differently to the monsoon season as evident from multivariate analyses.

Anthropogenic contaminants of high concern: Existence in water resources and their adverse effects

Existence of anthropogenic contaminants (ACs) in different environmental matrices is a serious and unresolved concern. For instance, ACs from different sectors, such as industrial, agricultural, and pharmaceutical, are found in water bodies with considerable endocrine disruptors potency and can damage the biotic components of the environment. The continuous ACs exposure can cause cellular toxicity, apoptosis, genotoxicity, and alterations in sex ratios in human beings. Whereas, aquatic organisms show bioaccumulation, trophic chains, and biomagnification of ACs through different entry route. These problems have been found in many countries around the globe, making them a worldwide concern. ACs have been found in different environmental matrices, such as water reservoirs for human consumption, wastewater treatment plants (WWTPs), drinking water treatment plants (DWTPs), groundwaters, surface waters, rivers, and seas, which demonstrate their free movement within the environment in an uncontrolled manner. This work provides a detailed overview of ACs occurrence in water bodies along with their toxicological effect on living organisms. The literature data reported between 2017 and 2018 is compiled following inclusion-exclusion criteria, and the obtained information was mapped as per type and source of ACs. The most important ACs are pharmaceuticals (diclofenac, ibuprofen, naproxen, ofloxacin, acetaminophen, progesterone ranitidine, and testosterone), agricultural products or pesticides (atrazine, carbendazim, fipronil), narcotics and illegal drugs (amphetamines, cocaine, and benzoylecgonine), food industry derivatives (bisphenol A, and caffeine), and personal care products (triclosan, and other related surfactants). Considering this threatening issue, robust detection and removal strategies must be considered in the design of WWTPs and DWTPs.

Candidate Animal Disease Model of Elizabethkingia Spp. Infection in Humans, Based on the Systematic Pathology and Oxidative Damage Caused by E. miricola in Pelophylax nigromaculatus

Most species of the genus Elizabethkingia are pathogenic to humans and animals, most commonly causing meningitis. However, our understanding of the pathogenic mechanisms involved is poor and there have been few pathological studies of Elizabethkingia spp. in animals. To understand the host injury induced by Elizabethkingia spp., we established a model of E. miricola infection in the black-spotted frog (Pelophylax nigromaculatus). The systematic pathology in and oxidative damage in the infection model were investigated. Our results show that recently isolated E. miricola is a bacterium that mainly parasitizes the host brain and that neurogenic organs are the predominant sites of damage. Infection mainly manifested as severe brain abscesses, meningoencephalitis, necrotic spondylitis, and necrotic retinitis. The liver, spleen, kidney, gastrointestinal tract, and lung were also affected to varying degrees, with bacterial necrotic inflammation. P. nigromaculatus also suffered enormous damage to its oxidative system during E. miricola infection, which may have further aggravated its disease state. Our results provide a preliminary reference for the study and treatment of Elizabethkingia spp.-induced neurological diseases in animals.

Larval exposure to environmentally relevant concentrations of triclosan impairs metamorphosis and reproductive fitness in zebrafish

Developmental exposure to endocrine disruptors can cause organizational changes resulting in latent and transgenerational disease. We exposed zebrafish to environmentally relevant concentrations of triclosan during the critical period of metamorphosis and somatic sex differentiation to determine effects on metamorphosis and reproduction. We use biological and morphological biomarkers to predict potential modes of action. Larval exposure to environmentally relevant concentrations of triclosan was sufficient to cause adverse effects in adults and their offspring. TCS exposure delays metamorphosis and impairs fecundity and fertility. Offspring from TCS-exposed fish show decreased survival and delayed maturation, but their reproductive capacity is not altered. Delays in metamorphosis in conjunction with morphological indicators suggest that toxicity may result from lowered thyroid hormones in parental fish. This work illustrates the importance of evaluating the latent effects of early exposure to environmental contaminants, and that further studies to evaluate the effects of triclosan on the thyroid axis are warranted.