Cycloart-24-ene-26-ol-3-one,a New Cycloartane Isolated from Leaves of Aglaia exima Triggers Tumour Necrosis Factor-Receptor 1-Mediated Caspase-Dependent Apoptosis in Colon Cancer Cell Line

Plants in the Meliaceae family are known to possess interesting biological activities, such as antimalaral, antihypertensive and antitumour activities. Previously, our group reported the plant-derived compound cycloart-24-ene-26-ol-3-one isolated from the hexane extracts of Aglaia exima leaves, which shows cytotoxicity towards various cancer cell lines, in particular, colon cancer cell lines. In this report, we further demonstrate that cycloart-24-ene-26-ol-3-one, from here forth known as cycloartane, reduces the viability of the colon cancer cell lines HT-29 and CaCO-2 in a dose- and time-dependent manner. Further elucidation of the compound’s mechanism showed that it binds to tumour necrosis factor-receptor 1 (TNF-R1) leading to the initiation of caspase-8 and, through the activation of Bid, in the activation of caspase-9. This activity causes a reduction in mitochondrial membrane potential (MMP) and the release of cytochrome-C. The activation of caspase-8 and -9 both act to commit the cancer cells to apoptosis through downstream caspase-3/7 activation, PARP cleavage and the lack of NFkB translocation into the nucleus. A molecular docking study showed that the cycloartane binds to the receptor through a hydrophobic interaction with cysteine-96 and hydrogen bonds with lysine-75 and -132. The results show that further development of the cycloartane as an anti-cancer drug is worthwhile.     

A novel multiplex assay for simultaneous quantification of total and S129 phosphorylated human alpha-synuclein

Background

Alpha-synuclein (asyn) has been shown to play an important role in the neuropathology of Parkinson’s disease (PD). In the diseased brain, classic intraneuronal inclusions called Lewy bodies contain abnormal formations of asyn protein which is mostly phosphorylated at serine 129 (pS129 asyn). This suggests that post-translational modifications may play a role in the pathogenic process. To date, several uniplex assays have been developed in order to quantify asyn not only in the brain but also in cerebrospinal fluid and blood samples in order to correlate asyn levels to disease severity and progression. Notably, only four assays have been established to measure pS129 asyn specifically and none provide simultaneous readout of the total and pS129 species. Therefore, we developed a sensitive high-throughput duplex assay quantifying total and pS129 human asyn (h-asyn) in the same well hence improving accuracy as well as saving time, consumables and samples.

Results

Using our newly established duplex assay we measured total and pS129 h-asyn in vitro showing that polo-like kinase 2 (PLK2) can phosphorylate asyn up to 41 % in HEK293 cells and in vivo the same kinase phosphorylated h-asyn up to 17 % in rat ventral midbrain neurons. Interestingly, no increase in phosphorylation was observed when PLK2 and h-asyn were co-expressed in rat striatal neurons. Furthermore, using this assay we investigated h-asyn levels in brain tissue samples from patients with PD as well as PD dementia and found significant differences in pS129 h-asyn levels not only between disease tissue and healthy control samples but also between the two distinct disease states especially in hippocampal tissue samples.

Conclusions

These results demonstrate that our duplex assay for simultaneous quantification is a useful tool to study h-asyn phosphorylation events in biospecimens and will be helpful in studies investigating the precise causative link between post-translational modification of h-asyn and PD pathology.

     

Analysis of Methanogenic Archaeal and Sulphate Reducing Bacterial Populations in Deep Sediments of the Black Sea

In this study, the distribution, morphology and relative abundance of Sulfate Reducing Bacterial (SRB) and Methanogenic Archaeal (MA) populations in the Black Sea sediments were investigated by using in situ hybridization with fluorescently labeled rRNA-targeted oligonucleotide probes. Results were discussed with respect to the characteristics of sampling points. MA and SRB showed a great diversity in all sediment samples. Higher abundance of MA (20–30%) and SRB (30–35%) populations were observed within the sediments from deeper parts of the Black Sea than the shallower parts (10–11% MA and 13–14% SRB). Desulfobotulus, Desulfosarcina and Desulfococcus groups were the most commonly detected SRB groups in the Black Sea sediments. Relative percentage of these SRB groups within sediments from deeper parts of the Black Sea was in a range of 17–21% whereas that of was in a range of 4–5% within the sediments from the shallower parts. Order Methanococcales were the dominant methanogenic group in all samples. Relative percentages of order Methanococcales were in a range of 8–12% and 4–5% within sediments from deeper parts and the coastal parts of the Black Sea, respectively.     

A global metagenomic map of urban microbiomes and antimicrobial resistance

1. Download : Download high-res image (148KB)
2. Download : Download full-size image

     

Selenium and Vitamin E Modulates Radiation-Induced Liver Toxicity in Pregnant and Nonpregnant Rat: Effects of Colemanite and Hematite Shielding

The levels of liver lipid peroxidation, glutathione peroxidase, reduced glutathione, and vitamins A and E were used to follow the level of oxidative damage caused by ionizing radiation in pregnant rats. The possible protective effects of selenium and vitamin E supplemented to rats housed in concrete-protected cages using hematite and colemanite were tested and compared to untreated controls. Ninety-six rats were randomly divided into four main equal groups namely control (A), normal concrete (B), concrete containing colemanite (C), and concrete containing hematite (D). Except group A, all groups exposed to 7 Gy radiation. The four main groups were divided into four subgroups each as follows: subgroups 1 (n?=?6): nonpregnant control rats. Subgroups 2 (n?=?6): selenium and vitamin E combination was intraperitoneally (i.p.) given to the nonpregnant rats for 20 days. Subgroups 3 (n?=?6): pregnant control rats. Subgroups 4 (n?=?6): selenium and vitamin E combination was i.p. given to the pregnant rats for concessive 20 days. Lactate dehydrogenate, alkaline phosphates, and lipid peroxidation values were higher in subgroups 1 and 3 than in no radiation group although glutathione peroxidase and vitamin E levels in liver were lower in radiation group than in no radiation group. Lactate dehydrogenate activity and lipid peroxidation levels were found to be decreased in subgroups 2 and 4 protected with concrete containing hematite and colemanite when compared to subgroup 1 and 3 with normal concrete. The radiation doses in rats housed by concrete without colemanite and hematite exposed radiation clearly showed liver degeneration. In conclusion, selenium and vitamin E supplementations and housing by concrete with colemanite was found to offer protection against gamma-irradiation-induced liver damage and oxidative stress in rats, probably by exerting a protective effect against liver necrosis via its free radical scavenging and membrane stabilizing. Protective effects of colemanite in the liver seem to be more important than in hematite.     

Morphological and physiological response of tomato (Solanum lycopersicum L.) to natural and synthetic cytokinin sources: a comparative study

Among the natural plant growth stimulants, moringa has attained enormous attention due to its leaf composition being enriched with cytokinin, antioxidants and minerals. Exogenous application of moringa leaf extract (MLE) improves productivity in many crops. This study investigated the potential of MLE with different dilutions, i.e., MLE0, MLE10, MLE20 and MLE30 (0, 10, 20 and 30 times diluted in water, respectively) to improve the performance of tomato. Foliage-applied water and benzylaminopurine (BAP, 50 mg L^?1) were taken as controls. Among treatments, foliar-applied MLE30 produced maximum vegetative and flowering branches, number of flowers and heaviest fruits per plant of tomato in comparison with synthetic BAP and other treatments. A similar increase in vegetative and flowering branches was recorded for root-applied MLE20 including BAP. Foliage-applied MLE30 also increased chlorophyll (a) pigments and leaf total soluble proteins than other stimulants used. This increase was followed by enhanced antioxidant activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), total phenolics in leaves and fruit lycopene contents of tomato. In general, foliar application of MLE30 was more effective as natural biostimulant to improve growth, productivity and fruit quality of tomato as compared to synthetic BAP and its root application.     

Selenium Reduces Mobile Phone (900 MHz)-Induced Oxidative Stress,Mitochondrial Function,and Apoptosis in Breast Cancer Cells

Exposure to mobile phone-induced electromagnetic radiation (EMR) may affect biological systems by increasing free oxygen radicals, apoptosis, and mitochondrial depolarization levels although selenium may modulate the values in cancer. The present study was designed to investigate the effects of 900 MHz radiation on the antioxidant redox system, apoptosis, and mitochondrial depolarization levels in MDA-MB-231 breast cancer cell line. Cultures of the cancer cells were divided into four main groups as controls, selenium, EMR, and EMR?+?selenium. In EMR groups, the cells were exposed to 900 MHz EMR for 1 h (SAR value of the EMR was 0.36?±?0.02 W/kg). In selenium groups, the cells were also incubated with sodium selenite for 1 h before EMR exposure. Then, the following values were analyzed: (a) cell viability, (b) intracellular ROS production, (c) mitochondrial membrane depolarization, (d) cell apoptosis, and (e) caspase-3 and caspase-9 values. Selenium suppressed EMR-induced oxidative cell damage and cell viability (MTT) through a reduction of oxidative stress and restoring mitochondrial membrane potential. Additionally, selenium indicated anti-apoptotic effects, as demonstrated by plate reader analyses of apoptosis levels and caspase-3 and caspase-9 values. In conclusion, 900 MHz EMR appears to induce apoptosis effects through oxidative stress and mitochondrial depolarization although incubation of selenium seems to counteract the effects on apoptosis and oxidative stress.