Tenothrips keruing sp. n. is described from Malaysia. This new species was taken from the flowers of Dipterocarpus sublamellatus (local name Keruing kerut) during the recent mass-flowering. The male of this species has a pair of stout setae on abdominal tergite IX, and there are no sternal pore plates. A key to species of Tenothrips from Indomalaysia is provided.
A new genus and three new species are described from the canopy of Dipterocarp forest in Pasoh Forest Research in Malaysia: Daunothrips gen. n., D. striatus sp. n., Scirtothrips convexum sp. n. and Scirtothrips longifacies sp. n. The morphological characters of these new members of the Scirtothrips genus-group are discussed and illustrated.
Staphylococcus aureus is usually considered a colonizer but can result in infections under favourable conditions, especially in the healthcare setting. Healthcare workers can be colonized by S. aureus, and may transmit them to patients under their care. We conducted a cross sectional study to determine the prevalence of S. aureus nasal carriers among medical students in Universiti Putra Malaysia (UPM) (from January to June 2011). Our study involved 209 medical students comprising of 111 and 97 preclinical and clinical students respectively. A selfadministered questionnaire was distributed and nasal swabs were collected. Upon identification, the antibiotic susceptibility of the isolates was examined followed by categorical analysis (Chi-square and Fisher's exact tests) with factors associated with S. aureus nasal carriage. Twenty one (10%) S. aureus strains were isolated from 209 nasal swab samples. 14 isolates were from pre-clinical students while the remaining seven were from clinical students. There was no significant association between gender, ethnicity, health status, skin infection and students' exposure to hospital environment with S. aureus nasal carriage (p>0.05). Nineteen (90.5%) isolates were resistant to penicillin and there was also no significant association between penicillin resistant and the students' groups. One (5.3%) isolate was resistant to erythromycin. There was no methicillin-resistant S. aureus isolated in this study.
Glucoraphenin, a glucosinolate present in large quantities in radish is hydrolysed by myrosinase to form the isothiocyanate sulforaphene, which is believed to be responsible for its chemopreventive activity; however, the underlying mechanisms of action have not been investigated, particularly in human cell lines. The aim of the study is to assess the cytotoxicity of sulforaphene in HepG2 cells and evaluate its potential to enhance apoptosis. The cytotoxicity of sulforaphene in HepG2 cells was carried out ensuing an initial screening with two other cell lines, MFC-7 and HT-29, where sulforaphene displayed highest toxicity in HepG2 cells following incubation at 24, 48 and 72 h. In contrast, the intact glucosinolate showed no cytotoxicity. Morphological studies indicated that sulforaphene stimulated apoptosis as exemplified by cell shrinkage, blebbing, chromatin condensation, and nuclear fragmentation. The Annexin V assay revealed significant increases in apoptosis and the same treatment increased the activity of caspases -3/7 and -9, whereas a decline in caspase-8 was observed. Impairment of cell proliferation was indicated by cell cycle arrest at the Sub G₀/G₁ phase as compared to the other phases. It may be concluded that sulforaphene, but not its parent glucosinolate, glucoraphenin, causes cytotoxicity and stimulates apoptosis in HepG2 cells.
Glucoraphasatin (GRH), a glucosinolate present abundantly in the plants of the Brassicaceae family, is hydrolyzed by myrosinase to raphasatin, which is considered responsible for its cancer chemopreventive activity; however, the underlying mechanisms of action have not been investigated, particularly in human cell lines. The aims of this study are to determine the cytotoxicity of raphasatin, and to evaluate its potential to cause apoptosis and modulate cell cycle arrest in human breast adenocarcinoma MCF-7 cells. The cytotoxicity was determined following incubation of the cells with glucoraphasatin or raphasatin (0⁻100 µM), for 24, 48, and 72 h. GRH displayed no cytotoxicity as exemplified by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. When myrosinase was added to the incubation system to convert GRH to raphasatin, cytotoxicity was evident. Exposure of the cells to raphasatin stimulated apoptosis, as was exemplified by cell shrinkage, membrane blebbing, chromatin condensation, and nuclear fragmentation. Moreover, using Annexin V-FITC assay, raphasatin induced apoptosis, as witnessed by changes in cellular distribution of cells, at different stages of apoptosis; in addition, raphasatin caused the arrest of the MCF-7 cells at the G₂ + M phase. In conclusion, raphasatin demonstrated cancer chemopreventive potential against human breast adenocarcinoma (MCF-7) cells, through induction of apoptosis and cell cycle arrest.
Gluconasturtiin, a glucosinolate present in watercress, is hydrolysed by myrosinase to form gluconasturtiin-isothiocyanate (GNST-ITC), which has potential chemopreventive effects; however, the underlying mechanisms of action have not been explored, mainly in human cell lines. The purpose of the study is to evaluate the cytotoxicity of GNST-ITC and to further assess its potential to induce apoptosis. GNST-ITC inhibited cell proliferation in both human hepatocarcinoma (HepG2) and human breast adenocarcinoma (MCF-7) cells with IC50 values of 7.83 µM and 5.02 µM, respectively. Morphological changes as a result of GNST-ITC-induced apoptosis showed chromatin condensation, nuclear fragmentation, and membrane blebbing. Additionally, Annexin V assay showed proportion of cells in early and late apoptosis upon exposure to GNST-ITC in a time-dependent manner. To delineate the mechanism of apoptosis, cell cycle arrest and expression of caspases were studied. GNST-ITC induced a time-dependent G2/M phase arrest, with reduction of 82% and 93% in HepG2 and MCF-7 cell lines, respectively. The same treatment also led to the subsequent expression of caspase-3/7 and -9 in both cells demonstrating mitochondrial-associated cell death. Collectively, these results reveal that GNST-ITC can inhibit cell proliferation and can induce cell death in HepG2 and MCF-7 cancer cells via apoptosis, highlighting its potential development as an anticancer agent.