Toxicity of TiO2, SiO2, ZnO, CuO, Au and Ag engineered nanoparticles on hatching and early nauplii of Artemia sp.

The potential of environmental release enhances with increased commercial applications of the nanomaterials. In this work, a simple and efficient test to estimate the acute toxicity of nanoparticles is carried out on Artemia species and their hatching rates. We have tested six different engineered nanoparticles (silver, gold, copper oxide, zinc oxide, TiO2 and SiO2 nanoparticles) and three soluble salts (CuSO4, ZnSO4 and AgNO3) on Artemia sp. The physicochemical properties of the nanoparticles involved in this study were analyzed in normal water and marine water. Hydrated and bleached Artemia cysts were allowed to hatch in continuously aerated, filtered sterile salt water containing nanoparticles; hatching of viable nauplii and total hatchlings have been recorded. In parallel, standard Artemia toxicity test was conducted on the nauplii monitoring the viability. In hatching experiments, a reduction in hatching rate was observed along with mortality of newly hatched nauplii. The results of the hatching experiment and of the standard Artemia test showed a good correlation. The toxicity of the nanoparticles was compared and the order of toxicity was estimated as Ag>CuO>ZnO>Au>TiO2>SiO2. The study thus suggests that the hatching test itself is a reliable assay for determining the toxicity of nanomaterials.

Fly ash effect on hatching, mortality and penetration of root-knot nematode (Meloidogyne incognita) in pumpkin roots

An experiment was conducted to observe the effect of fly ash on hatching, mortality and penetration of root-knot nematode (Meloidogyne incognita) in pumpkin roots. For hatching experiment different fly ash-extract concentrations (5, 10, 20, 30, 40, and 50%) were prepared. Hatching was significantly reduced in all concentrations, maximum being at 50% concentration. The mortality (%) of juveniles was observed in 1, 2, 3, 4, 5, 6 and 7th days with different levels (5, 10, 20, 30, 40 and 50 %) of fly ash-extract. All the levels were found harmful to juveniles. As the level was increased, the killing percentage of juveniles was also increased. Highest mortality was observed in 7th day with 50% level.For the penetration experiment, fly ash was mixed with soil to prepare different concentrations (5, 10, 20, 30, 40, and 50%). Seeds of pumpkin were grown in coffee cups filled with different mixtures. At two leaf stage, seedlings were inoculated with 2000 larvae. The penetrated larvae in roots were observed after 1, 2, 3, 4, 5, 6 and 7 days. Root penetration was found inversely proportional to concentration. Significant results in the suppression of nematode penetration were noted up to 40% concentration. However, none of the juveniles was penetrated at 50% concentration.International Journal of Environment Vol.5(3) 2016, pp.66-73

Diversity of cryptic Metazoa in Australian freshwaters: a new genus and two new species of sessile rotifer (Rotifera, Monogononta, Gnesiotrocha, Flosculariidae)

Rotifers are obligate aquatic animals that are reputed to have particularly efficient mechanisms to survive extreme, or prolonged periods of drought, in the form of inconspicuously small resting stages, hidden between plant litter and sediment. In order to study this phenomenon, we conducted a hatching experiment on dry sediment from two billabongs in Victoria, Australia, which had been stored under dehydrated conditions for about one year. Here, we report on the diversity of rotifers that hatched during the experiment. A total of 48 species, a majority of which belong to groups of sessile rotifers, were recorded, including several new or interesting taxa. Two new taxa are described: Floscularia wallacei n. spec., and Pentatrocha gigantea n. gen., n. spec., the largest rotifer ever recorded. Ptygura ctenoida Koste & Tobias, 1990 is raised to species rank.

Experiments On the Relationship Between the Hen and Chick (Gallus Gallus): the Role of the Auditory Mode in Recognition and the Effects of Maternal Separation

In a series of 6 experimental studies, the means by which a chick recognises its mother, and the reversibility of filial attachments were examined using bantam hens and their chicks. In a simultaneous discrimination test it was determined that the chick could discriminate between own and alien hens by means of the hens' cluck vocalizations, on the 4th and 8th days post hatching, (Experiment 1). The chicks could make this discrimination more efficiently when live hens were presented (Experiment 2). On separating the hen and chicks for 4 h on the 4th day, the chicks could no longer discriminate between own and an alien live hen (Experiment 3) while they would accept an alien hen, (Experiment 4). These findings suggest that maternal-filial bonds may be reversed with little difficulty. Thus Experiment 5 was designed to examine the stability of these later maternal filial bonds. Chicks spent the first 3 days post hatching, with the hen who incubated the eggs. Then they spent 3 days with an alien hen, after which 3 days isolation followed. It was found that chicks could discriminate in favour of their own hen after the first period of exposure, and in favour of the alien hen after the second period of exposure. Following 3 days isolation they showed no preference for either hen. Experiment 6 was essentially a replication of Experiment 5, but included a control for familiarity. Only one test took place after the 3 days isolation. The chicks were presented with the 1st 2nd and an unfamiliar alien hen. The chicks did not discriminate in favour of any particular hen. It is concluded that after 4 h or 3 days isolation, the chicks did not discriminate between the hens presented, yet they remained responsive to hens.

Potato Eelworm (Heterodera schachtii): Further investigations

The investigations described in this paper are in part a continuation of those described by Carroll and McMahon in a previous paper published in 1935. The previous paper demonstrated the fact that the root excretion of potatoes growing in recently sterilized soil does not possess the power of inducing the hatching of eelworm eggs in the normal manner. It was shown that when eelworm cysts were placed in soil leaching (containing potato root excretion) obtained from pots of very recently sterilized soil growing potatoes practically no hatch of the eggs in these cysts took place until after the lapse of about thirty days. It was further indicated that this interval of time which elapses before hatching commences diminishes according as the period between time of sterilization of the soil and time of obtaining soil leaching for hatching experiment increases.