Expression of a X. laevis tRNATyr gene has been studied in mammalian cells. This tRNATyr gene has a 13 base intervening sequence adjacent to its anticodon. A fragment containing the tRNATyr gene was cloned into the late region of SV40. Cells infected with a recombinant virus stock vastly overproduce a tRNATyr that is properly spliced, processed and modified. It was also found that the X. laevis...

After microinjection of Xenopus laevis oocytes with RNA from avian myeloblastosis virus, viral structural proteins p27, p19, p15, and p12 are formed by a sequence of posttranslational cleavages of a high-molecular-weight precursor polypeptide. The 60-70S RNA aggregate or its 30-40S RNA subunits obtained by heat or formamide treatment possess the same ability to serve as template in X. laevis oo...

The homology model of major haemoglobin component HbA1 of the African Clawed Frog was predicted using the pigeon (Columba livia) haemoglobin as a template. The model was built with the help of MODELLER9v8. The models were evaluated with ProSA and PROCHECK. In X. laevis Gln38α is unable to form a hydrogen bond with β97His or β99Asp, which is responsible for the increase in oxygen affinity of the...

Membrane transport proteins (transporters and ion channels) have been extensively expressed in amphibian oocytes. The aims of this study were to determine whether oocytes from the cane toad Bufo marinus could be used as an alternative expression system to the broadly used Xenopus laevis oocytes. mRNAs encoding plasma membrane transporters NaSi-1 and sat-1 (sulphate transporters), NaDC-1 (dicarb...

Atrazine is one of the major surface water contaminants in the midwestern United States. Speculations have arisen on the potential effects of atrazine contamination to anuran larvae developing in these surface waters. In this study, Xenopus laevis tadpoles were exposed to environmentally relevant concentrations of atrazine. Nuclear and morphological endpoints were used to assess the effects of ...

In a small isolated lake in Slovakia, the fish acanthocephalan Pomphorhynchus laevis using Gammarus balcanicus and the minnow Phoxinus phoxinus, respectively, as its intermediate and final hosts, represented a dominant helminth species. Its prevalence and intensity of infection in fish showed no significant variation during a year fluctuating above the mean values of 89% and 6.6 worms per fish....

PURPOSE Because of their high cone/rod ratio, Xenopus laevis may be a useful system for examining rod-cone interactions during retinal degeneration and mechanisms that underlie secondary cone degeneration. The authors developed an inducible model of retinitis pigmentosa (RP) in X. laevis to investigate these issues. METHODS The authors generated transgenic X. laevis that express a modified ca...

The fluctuation of the population of Daphnia laevis in Lake Jacaré (Middle River Doce, Minas Gerais) was monitored monthly (at one point in the limnetic region) for six years (2002-2007) as part of the Program of Long-Term Ecological Research (LTER/UFMG). The following parameters were also monitored: water temperature, pH, electrical conductivity, dissolved oxygen, chlorophyll a, total phosphor...

Developing Xenopus laevis experience two periods of muscle differentiation, once during embryogenesis and again at metamorphosis. During metamorphosis, thyroid hormone induces both muscle growth in the limbs and muscle death in the tail. In mammals, the muscle creatine kinase (MCK) gene is activated during the differentiation from myoblasts to myocytes and has served as both a marker for muscle...

Congenital heart defects often include altered conduction as well as morphological changes. Model organisms, like the frog Xenopus laevis, offer practical advantages for the study of congenital heart disease. X. laevis embryos are easily obtained free living, and the developing heart is readily visualized. Functional and morphological evidence for a conduction system is available for adult frog...