Distinct roles of Akt1 and Akt2 in regulating cell migration and epithelial-mesenchymal transition

The Akt family of kinases are activated by growth factors and regulate pleiotropic cellular activities. In this study, we provide evidence for isoform-specific positive and negative roles for Akt1 and -2 in regulating growth factor-stimulated phenotypes in breast epithelial cells. Insulin-like growth factor-I receptor (IGF-IR) hyperstimulation induced hyperproliferation and antiapoptotic activities that were reversed by Akt2 down-regulation. In contrast, Akt1 down-regulation in IGF-IR-stimulated cells promoted dramatic neomorphic effects characteristic of an epithelial-mesenchymal transition (EMT) and enhanced cell migration induced by IGF-I or EGF stimulation. The phenotypic effects of Akt1 down-regulation were accompanied by enhanced extracellular signal-related kinase (ERK) activation, which contributed to the induction of migration and EMT. Interestingly, down-regulation of Akt2 suppressed the EMT-like morphological conversion induced by Akt1 down-regulation in IGF-IR-overexpressing cells and inhibited migration in EGF-stimulated cells. These results highlight the distinct functions of Akt isoforms in regulating growth factor-stimulated EMT and cell migration, as well as the importance of Akt1 in cross-regulating the ERK signaling pathway.     

Ultrastructure of Spermatozoa in a Freshwater Fairy Shrimp, <Emphasis Type="Italic">Streptocephalus dichotomus</Emphasis> (Crustacea: Anostraca)

Ultrastructure of spermatozoa in fairy shrimp Streptocephalus dichotomus revealed that they are amoeboid type with no acrosome and flagella. Surface topography of the spermatozoon is smooth with occasional pseudopodial projections. Transmission electron micrographs of spermatozoa show organelle and the mitochondria which is not fused to form the so called ‘Nebenkern’. The testicular lumen reveals spermatozoa in varying sizes and shapes.     

The filtration apparatus of Anostraca (Crustacea): species-specific setulation in the genus Streptocephalus

The structure of the setae, setules, spines and spinules on the limbs of males and females of Streptocephalus torvicornis, S. rubricaudatus and S. proboscideus are described, based on scanning electron micrographs. The data disclose significant variation among the three species in fine structure of the setules and inter-setular distance. The variation may be related to different trophic specialisations, facilitating the sympatric occurrence of congeneric species.     

A niche-defying feat: induced oligoneogenesis in the adult dentate gyrus

In a recent paper in Nature Neuroscience, Jessberger et al. (2008) report that overexpression of ASCL1 (mash1) directs adult hippocampal progenitors to adopt an oligodendrocytic fate. The effect is specific to the hippocampal niche in vivo, indicating that cell-autonomous and niche-defined factors collaborate to instruct cell fate choices.     

Compensatory changes in enzymes of arginine metabolism during renal hypertrophy in mice

The present study investigates enzyme activities of the urea cycle, transamidinase and ornithine–proline inter-conversion in the hypertrophied kidney after unilateral nephrectomy in mice. Surgical removal of the left kidney in mice led to compensatory enlargement of the right kidney after 1 and 14 days. This renal growth was associated with an increase in glomerular volume (but not number) and enlargement of the proximal convoluted tubules. The total renal protein content increased in proportion to the increase in kidney weight, but the protein per gram weight of kidney did not change. The specific activity of only ornithine aminotransferase (OAT), the rate-limiting enzyme in the conversion of ornithine to proline, increased in 2 weeks of hypertrophy. The specific activity of all other enzymes was unchanged. However, the total enzyme activity per kidney of all the enzymes, without exception, was elevated in the hypertrophied kidney. While the increase in total OAT activity was much more than the increase in kidney weight, all other enzymes increased more or less in proportion to the increase in renal mass. The results suggest that compensation in OAT activity to chronic reduction in renal mass was complete, but only partial in the case of other enzymes.     

Metabolism of 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene by Alcaligenes denitrificans

Metabolism of 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (DDE), a persistent metabolite of 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT), by an Alcaligenes denitrificans was optimal under `non-shaking' conditions, was accelerated by adding 1 g glucose l^–1, and inhibited by 1 g sodium acetate l^–1 or 1 g sodium succinate l^–1. Addition of biphenyl, in the vapor form, to the reaction mixture did not enhance DDE metabolism. During the reaction, accumulation of conventional metabolites, 1-chloro-2,2-bis(4-chlorophenyl)ethylene (DDMU) and 4-chlorobenzoate, was not observed.     

In vitro studies on the effects of some anthelmintics on Cotylophoron cotylophorum (Digenea, Paramphistomidae): a structural analysis.

The effects of the anthelmintics praziquantel (PZQ), levamisole (LEV), mebendazole (MBZ), fenbendazole (FBZ) and albendazole (ABZ), on the morphology and the histology of a digenetic trematode, Cotylophoron cotylophorum, were studied. Scanning electron micrographs of the drug-treated worms revealed that PZQ was the most effective drug inducing surface damages to a great extent. The parasite exposed to PZQ for 6 h, showed smaller blebs on the oral sucker region as well as on the sensory papillae. These blebs enlarged in size after 24 h and ruptured after 30 h of exposure. The worms treated with LEV showed a few smaller blebs on the ventrolateral margin. In MBZ- and FBZ-treated worms the blebs appeared between the oral and genital sucker after 6 h of incubation. The changes were not apparent in the ABZ-treated worms.     

Primary ovarian cancer cell inhibition by human Wharton's Jelly stem cells (hWJSCs): Mapping probable mechanisms and targets using systems oncology

Ovarian cancer is one of the most lethal gynaecological cancers. Its subtle onset and absence of symptoms in early stages are associated with poor prognosis and high mortality. Identification of early biomarkers would aid in ovarian cancer control. Mesenchmal stem cells (MSCs) and/or their secretory products are identified to have cancer inhibitory properties. Therefore, it is of interest to study the anticancer properties of human Wharton''s jelly stem cells conditioned medium (hWJSCs-CM) on primary ovarian carcinoma cells in vitro. Primary cultures of epithelial ovarian carcinoma cells (EOCs) and hWJSCs were used in this study. EOCs were exposed to hWJSC-CM (100%) for 24h-72h and changes in mophology and cell proliferation were monitored. Treatment with hWJSC-CM showed altered morphological changes that resulted in death of EOCs. Colorimetric assay [MTT, (3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide)] showed mean decreases in EOC proliferation by 16.21%, 23.89% and 40.08% at 24h, 48h and 72h respectively compared to control. Ingenuity Pathway Analysis (IPA, Igenuity Systems, USA) deduced important molecular pathways and signaling networks associated with cancer cell death and these correlated with significant expression of tumour suppresors and apoptotic genes in hWJSCs. Secretory products of hWJSC-CM induced cell death of EOCs via apoptosis. IPA identification of canonical genes/pathways involved in EOCs that overlap with hWJSCs tumour suppressors and apoptosis genes further support this hypotheis. Additional in vitro and in vivo studies are necessary to validate EOCs inhibition with hWJSC-extracts towards their mechanism of action.