The antimicrobial activity of different extracts of Piper regnellii was evaluated through the broth microdilution assay. The leaves, roots and stems extracts presented a good activity against Staphylococcus aureus and Bacillus subtilis with minimal inhibitory concentration (MIC) between 31.25 62.5 μg/ml. Although the differences were not significant, the leaves hydroalcoholic extract tended to ...

The Xenopus Cripto-1 protein is confined to the cells of the animal hemisphere during early embryogenesis where it regulates the formation of anterior structures. Cripto-1 protein accumulates only in animal cells because cripto-1 mRNA in cells of the vegetal hemisphere is translationally repressed. Here, we show that the RNA binding protein, Bicaudal-C (Bic-C), functioned directly in this veget...

The mitochondrial cloud is a unique cell structure found in stage I Xenopus oocytes that plays a role in mitochondriogenesis and in the distribution of germ plasm to the vegetal pole. Xcat-2 RNA specifically localizes to the mitochondrial cloud and moves with it to the vegetal subcortex in stage II oocytes. Later, in the 4-cell embryo, it is found in a pattern identical to the germ plasm. Follo...

Sea urchin embryos initiate cell specifications at the 16-cell stage by forming the mesomeres, macromeres and micromeres according to the relative position of the cells in the animal-vegetal axis. The most vegetal cells, micromeres, autonomously differentiate into skeletons and induce the neighbouring macromere cells to become mesoendoderm in the β-catenin-dependent Wnt8 signalling pathway. Alt...

In zebrafish, primordial germ cells (PGCs) are determined by a specialized maternal cytoplasm, the germ plasm, which forms at the distal ends of the cleavage furrows in 4-cell embryos. The germ plasm includes maternal mRNAs from the germline-specific genes such as vasa and nanos1, and vegetally localized dazl RNA is also incorporated into the germ plasm. However, little is known about the distr...

The maternal transcription factor VegT is important for establishing the primary germ layers in Xenopus. In previous work, we showed that the vegetal masses of embryos lacking maternal VegT do not produce mesoderm-inducing signals and that mesoderm formation in these embryos occurred ectopically, from the vegetal area rather than the equatorial zone of the blastula. Here we have increased the e...

In Xenopus laevis, dorsal cells that arise at the future dorsal side of an early cleaving embryo have already acquired the ability to cause axis formation. Since the distribution of cytoplasmic components is markedly heterogeneous in an egg and embryo, it has been supposed that the dorsal cells are endowed with the activity to form axial structures by inheriting a unique cytoplasmic component o...

Sialolithiasis is a relatively frequent occurrence; however, cases of sialolithiasis originating around a "foreign body" nidus are rare. We describe a patient with submandibular sialolithiasis organized around a vegetal nidus and discuss the etiology of the case.

The mesoderm of Xenopus laevis and other amphibia is formed through an inductive interaction during which cells of the vegetal hemisphere act on cells of the animal hemisphere. Two groups of factors mimic the effects of the vegetal hemisphere. One group consists of members of the fibroblast growth factor (FGF) family, while the other is related to transforming growth factor type beta (TGF-beta)...

In this work we aimed to characterise the diet of Astyanax taeniatus (Jenyns 1842) (Characiformes, Characidae) along the Mato Grosso stream and we hypothesised that the diet of this species would vary according to spatial, seasonal and ontogenetic differences. Specimens were collected every second month at three sites with different physical attributes. The feeding habits of 651 specimens were ...