Harmful Effects of Nanoparticles on Animals

Since several years nanoparticles (NPs) are produced by industries and used in several fields of activities. They are finally found in aquatic and terrestrial environments, where they are ingested by living organisms in which they accumulate, before being eliminated. In organisms, NPs represent foreign elements with their own physicochemical properties due to their small size. So NPs may interfere with the normal physiological mechanisms of the embryos, growing animals, and adults, and it is indispensable to understand their potentially direct or indirect harmful effects on living organisms. It has been already shown that NPs could be toxic to bacteria, algae, invertebrates, and vertebrates. In this review, several examples of recent studies are given. We will examine successively the effects of NPs on terrestrial and semiaquatic and aquatic vertebrate and invertebrate animals.

Visualization of gene expression of prolactin-receptor (PRL-R) by in situ hybridization in reproductive organs of Typhlonectes compressicauda, a gymnophionan amphibian

The expression of the long form of prolactin receptor (PRL-R) mRNAs was studied in reproductive organs from both male and female Typhlonectes compressicauda, an amphibian, by quantitative in situ hybridization. These PRL-R mRNAs were expressed in all the organs studied. In ovarian tissue, mRNAs coding for the long form of PRL-R were strongly expressed in ovaries with compact and vascularized corpora lutea, i.e., during the middle and the end of pregnancy. During the other periods of cycle, sexual rest, vitellogenesis and beginning of pregnancy, expression of these mRNAs was lower than in other periods. In the testis, mRNAs coding for the long form of PRL-R were expressed in germ cells as well as in Leydig and Sertoli cells. In müllerian glands, important variations of expression in these mRNAs have been observed with a large increase during the breeding period and a decrease during sexual rest. Variations of gene expression of the long form of PRL-R for all tissues studied are correlated to synthesis of PRL in the pituitary in both male and female Typhlonectes compressicauda.

Visualization of gene expression of prolactin receptors (PRL-R) by in situ hybridization, in Typhlonectes compressicaudus, a gymnophionan amphibian

The expression of the short and long forms of prolactin receptors (PRL-R) mRNA was studied in various types of tissue from Typhlonectes compressicaudus, an amphibian, by quantitative in situ hybridization. Both forms were expressed in all the types of tissues studied. In the liver, small intestine and hypophysis, the mRNA coding for the short form of PRL-R was more strongly expressed than the mRNA coding for the long form and vice-versa for the stomach, spleen and kidneys. In the female liver, quantification showed a higher value of mRNA expression mid-way through pregnancy than during the sexual inactivity period. This result was found to be correlated with the reserve function of the liver. In the kidney and small intestine, the presence of PRL-R was correlated with the hydromineral function. A comparison with certain mammals was also established. These results confirm the ubiquity of PRL effects on metabolic regulation, and suggest a phylogenic conservation of its receptors.

Immunohistochemical Localization of Calpains in the Amphibian Xenopus laevis

Though histochemical techniques have been used for decades, they are still very important in basic research. They make it possible to work on fixed tissues and provide a large amount of information in a relatively short time and at a low cost. Here we describe methods for indirect immunohistochemistry and immunofluorescence on sections of tadpoles and tissues of adult amphibians belonging to the species Xenopus laevis. The objective is to localize calpains within tissues in order to understand their involvement in cellular processes.