MAPK/ERK2 phosphorylates ERG at serine 283 in leukemic cells and promotes stem cell signatures and cell proliferation.

Aberrant ERG (v-ets avian erythroblastosis virus E26 oncogene homolog) expression drives leukemic transformation in mice and high expression is associated with poor patient outcomes in acute myeloid leukemia (AML) and T-acute lymphoblastic leukemia (T-ALL). Protein phosphorylation regulates the activity of many ETS factors but little is known about ERG in leukemic cells. To characterize ERG phosphorylation in leukemic cells, we applied liquid chromatography coupled tandem mass spectrometry and identified five phosphorylated serines on endogenous ERG in T-ALL and AML cells. S283 was distinct as it was abundantly phosphorylated in leukemic cells but not in healthy hematopoietic stem and progenitor cells (HSPCs). Overexpression of a phosphoactive mutant (S283D) increased expansion and clonogenicity of primary HSPCs over and above wild-type ERG. Using a custom antibody, we screened a panel of primary leukemic xenografts and showed that ERG S283 phosphorylation was mediated by mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling and in turn regulated expression of components of this pathway. S283 phosphorylation facilitates ERG enrichment and transactivation at the ERG +85 HSPC enhancer that is active in AML and T-ALL with poor prognosis. Taken together, we have identified a specific post-translational modification in leukemic cells that promotes progenitor proliferation and is a potential target to modulate ERG-driven transcriptional programs in leukemia.

In situ TEM and SEM studies on the antimicrobial activity and prevention of Candida albicans biofilm by Cassia spectabilis extract.

The inhibitory effect of Cassia spectabilis methanol leaf extract was evaluated against biofilm forming Candida albicans, which was sensitive to 6.25 mg/ml concentration of the extract. Transmission (TEM) and scanning electron microscope (SEM) observations were used to study the anticandidal activity and prevention of biofilm formation by the C. spectabilis extract. SEM analysis further revealed reduction in C. albicans biofilm in response to the extract. The main abnormalities noted via TEM study was the alterations in morphology and complete collapse of the yeast cells after 36 h of exposure to the extract. The significant antifungal activity shown by this methanol extract of C. spectabilis suggests its potential against infections caused by C. albicans.

Fungicidal effect and oral acute toxicity of Cassia spectabilis leaf extract.

The fungicidal activity of Cassia spectabilis leaf extracts was investigated using the disk diffusion technique and the broth dilution method. The extract showed a favorable antimicrobial activity against Candida albicans with a minimum inhibition concentration(MIC) value of 6.25 mg / ml. Apart from the fungicidal effects, imaging using scanning electron microscopy (SEM) was done to determine the major alterations in the microstructure of the C. albicans. The main abnormalities noted in the SEM studies were the alterations in morphology and complete collapse of the yeast cells after 36 h of exposure to the extract. The in vitro time-kill study performed using the leaf extract at 1/2, 1 or 2 times of the MIC significantly inhibited the yeast growth with a noticeable drop in optical density (OD) of yeast culture, thus confirming the fungicidal effect of the extract on C. albicans. In addition, in vivo antifungal activity studies on candidiasis in mice showed a 5-fold decrease in Candida in kidneys and blood samples in the groups of animals treated with the extract (2.5 g / kg body weight). In an acute toxicity study using mice, the acute minimum fatal dose of the extract was greater than 2000 mg / kg, and we found no histopathological changes in macroscopic examination by necropsy of mice treated with extract. We conclude that the extract may be safely used as an anticandidal agent.

Antimicrobial activities of Psophocarpus tetragonolobus (L.) DC extracts.

Consecutive chloroform, ethanol, and ethyl acetate partitions of extracts from winged bean [Psophocarpus tetragonolobus (L.) DC] root, stem, leaf, and pod extracts were tested for their antimicrobial activity against 19 microbial species, including 11 bacterial pathogens, four yeasts, and four molds using the disk diffusion assay technique. The pod extract was found to be most effective against all of the tested organisms, followed by the stem, root, and leaf extracts, and the ethanol fraction showed the most significant (p < 0.05) antimicrobial activity against all of the tests among three soluble fractions of extract, followed by the ethyl acetate and chloroform fractions. The minimum inhibitory concentrations (MICs) of extracts determined by the broth dilution method ranged from 1.25 to 10.0 mg/mL. The MIC of ethanol fraction of pod extracts was the lowest by comparison with the other two extracts. The MIC for fungi was at or below 2.5 mg/mL and for bacteria was at or above 2.5 mg/mL.

Antimicrobial activities and toxicity of crude extract of the Psophocarpus tetragonolobus pods.

The extract of the Psophocarpus tetragonolobus pods has been tested for antimicrobial activity in a disk diffusion assay on eight human pathogenic bacteria and two human pathogenic yeasts. The extracts of P. tetragonolobus possessed antimicrobial activity against all tested strains. The ethanolic extract of P. tetragonolobus pods was further tested for in vivo brine shrimp lethality test and in vitro sheep erythrocyte cytotoxic assay. The brine shrimp lethality test exhibited no significant toxicity (LC(50)=1.88 mg/ml) against Artemia salina, whereas sheep erythrocyte test showed significant toxicity. The reason for haemolysis of erythrocyte was discussed. The P. tetragonolobus extract with high LC(50) value signified that this plant is not toxic to human. This result also suggested that the ethanolic extract of P. tetragonolobus pods is potential source for novel antimicrobial compounds.