Lytic Enzymes of Aspergillus piperis as a Tool for Attacking Some Phytopathogenic Fungi In vitro with Special Reference to its Cytotoxicity

The antagonistic activity of Aspergillus piperis against Fusarium oxysporum f. sp. fabae (FOF) and Sclerotinia sclerotiorum were examined and showed multiple signs of hyphal interactions. Microscopic examination of contact regions among A. piperis and each pathogen revealed distinct enzymatic lysis of pathogenic hyphal cell walls. Therefore, it is important to estimate the lytic enzyme activity of A. piperis. Extracellular lytic enzymes are important offensive forces for A. piperis as a biological control agent. Chitinase, phospholipase, and protease recorded relatively high activity from a culture age of 10 days (82.3, 42.4, and 6.2 U/ml, respectively). Enzymatic persistence was measured at room temperature, recording relatively long periods, saving 54%, 46%, and 21% of their activity, respectively. The cytotoxicity of the crude culture filtrate of A. piperis was examined in MCF7 and WI38 human cell lines. The cell viability (IC50) value of the fungal filtrate was estimated after 24 h and 48 h. The results revealed that IC50 values against the MCF7 cell line were inoperative after 24 h and were recorded 80 μg/ml after 48 h. In contrast, IC50 values against the WI38 cell line were 85.69 and 69.8 μg/ml after 24 and 48 h, respectively.

Evaluation of photodynamic therapy and nuclear imaging potential of subphthalocyanine integrated TiO2 nanoparticles in mammary and cervical tumor cells

This study, subphthalocyanines (SubPc) and SubPc integrated TiO2 nanoparticles (SubPc-TiO[Formula: see text] were synthesized as novel photosensitizers. Their PDT effects were evaluated. Furthermore, nuclear imaging potential of [Formula: see text]I-labelled SubPc/SubPc-TiO2 were examined in mouse mammary carcinoma (EMT6) and cervix adenocarcinoma (HeLa) cell lines. The uptake results show that SubPc labelled with [Formula: see text]I radionuclide ([Formula: see text]I-SubPc) in EMT6 and HeLa cell lines was found to be approximately the same as in the WI38 cell line. However, the uptake values of SubPc-TiO2 labelled with [Formula: see text]I ([Formula: see text]I-SubPc-TiO[Formula: see text] in EMT6 and HeLa cell lines were determined to be two times higher than in the WI38 cell line. In other words, the target/non-target tissue ratio was identified as two in the EMT6 and HeLa cell lines. [Formula: see text]I-SubPc-TiO2 is promising for imaging or treatment of breast and cervix tumors. In vitro photodynamic therapy studies have shown that SubPc and SubPc-TiO2 are suitable agents for PDT. In addition, SubPc-TiO2 has higher phototoxicity than SubPc. As a future study, in vivo experiments will be held and performed in tumor-bearing nude mice.

Busulfan Selectively Induces Cellular Senescence Via a p53-Independent but Erk-p38 MAPK-Dependent Mechanism.

Busulfan (BU), an alkylating agent, has been used extensively for the depletion of leukemia cells and normal hematopoietic stem cells (HSCs) prior to bone marrow transplantation. However, its mechanism(s) of action is unknown. Our laboratory has previously shown that BU primarily depletes HSCs by induction of senescence, but not apoptosis. In the present study, we investigated the molecular mechanisms whereby BU induces cellular senescence utilizing WI38 human diploid fibroblasts as a model system. We found that WI38 fibroblasts incubated with BU (from 7.5 to 120μM) for 24 h underwent senescence but not apoptosis in a dose-independent manner, whereas cells incubated with 80μM and 20μM etoposide (Etop) committed to apoptosis and senescence, respectively. The induction of WI38 cell senescence by Etop was associated with p53 activation and could be attenuated by down-regulation of p53 using a-PFT or p53 siRNA. In contrast, WI38 cell senescence induced by BU was associated with prolonged activation of Erk, p38 and JNK, and could be suppressed by the inhibition of Erk and p38 MAPKs with PD98059 and SB203580, respectively. Upon release from Erk and p38 inhibition, BU-treated cells proceeded to DNA synthesis and cell division. However, inhibition of p53 with a-PFT or p53 siRNA, or JNK with SP600125, failed to protect WI38 cells from BU-induced senescence. These findings suggest that BU is a distinctive chemotherapeutic agent that can selectively induce cellular senescence through the Erk and p38 MAPK pathways.