Antibacterial greener silver nanoparticles synthesized using Marsilea quadrifolia extract and their eco-friendly evaluation against Zika virus vector, Aedes aegypti

Fabrication and use of nanoparticles have progressively enlarged within the last decade. Herein the silver nanoparticles (AgNps) were synthesized via the extract from Marsilea quadrifolia (Mq) as a decreasing and steadying mediator. The Mq-AgNPs demonstrated superior toxicity on Zika virus vector, Aedes aegypti with the LC50 value of 10.69 µg·mL−1. The Mq-AgNPs were established securely to non-target organisms Artemia nauplii and Ceriodaphnia cornuta, and no structural or anatomical alterations confirm its security to the surroundings. The antibacterial activity exposed that Mq-AgNPs showed superior growth inhibition effect against the tested bacteria. Furthermore, the Mq-AgNPs showed strong antioxidant activities when compared to Mq leaf extract. Overall, our results highlight that Mq-AgNPs are hopeful and biodegradable devices against mosquito vectors of therapeutic significance, with moderate toxicity against non-target aquatic animals.

Effects of PVC pipe leachates on the survival and reproduction of two micro-crustacean species Ceriodaphnia Cornuta and Daphnia Magna

The occurrence and impacts of plastic are among the most concerns on the environment, ecosystems, and human health in recent years. Plastic products may contain harmful additives (e.g. phthalate, bisphenol) which can easily be leached out of the surface of the plastic materials and enter the environment causing negative effects on organisms in aquatic ecosystems. However, the toxicity of the leached plastic additives on aquatic organisms including micro-crustaceans have not been fully understood. Therefore, this study aims to evaluate the chronic effects of the leachate from the polyvinyl chloride (PVC) water pipes at the concentration of 0, 10 and 100 mg PVC/L on the survival and reproduction of two micro-crustacean species: Daphnia magna, and Ceriodaphnia cornuta. The results showed that the leachate from PVC pipes at the concentration of 100 mg/L did not adversely affect on survival and reproduction of D. magna, but reduced up to 50% of the survival rate and 60% of the reproduction of C. cornuta. The tropical micro-crustacean species C. cornuta was more vulnerable than the temperate one, D. magna. The results revealed the potential health risks of the PVC water pipes C. cornuta was recommended to be used as a model organism for the toxicological investigation and environmental assessment.

High diversity of Cladocera (Crustacea: Branchiopoda) in a Ramsar site Lake Kud-Thing, Northeast Thailand

An intensive study of cladoceran diversity in Lake Kud-Thing, a Ramsar site of Bueng Kan Province, Thailand, was conducted. One hundred and twenty-five qualitative samples were collected from 15 localities during the period from June 2012 to November 2014. A total of 58 species belonging to 38 genera was recorded. Three species, Chydorus idrisi Sinev 2014, Karualona kwangsiensis (Chiang 1963) and Streblocerus cf. serricaudatus (Fisher 1849) are new records for Thailand. The most species rich family was Chydoridae (32 species, 55% of the encountered species in the lake) followed by Sididae (8 species, 14%) and Macrothricidae (8 species, 14%) while only a single species of Ilyocryptidae was observed. The most frequently encountered planktonic species were Ceriodaphnia cornuta Sars 1885, Bosmina cf. meridionalis Sars 1904 and Ephemeroporus barroisi (Richard 1894). A newly described chydorid, Anthalona spinifera Tiang-nga, Sinev & Sanoamuang 2016, was also recorded from this lake. The number of cladocerans recorded in this study is remarkably higher than that of previous studies in other natural lakes (17–40 species) within Thailand. In addition to earlier records, the number of cladocerans of Lake Kud-Thing has been updated to 62 species, about two times higher than that of other lakes in this region. Thus, our results suggest that Lake Kud-Thing is one of the biodiversity hotspots for Cladocera of Southeast Asia.