Geochemical Speciation and Risk Assessment of Heavy Metals in Sediments of a River in Bangladesh

The surface sediment of a downstream river (Paira) connected to the marine ecosystems of the Bay of Bengal was assessed by sequential extraction technique. The objectives of this study were to evaluate the mobility and dynamics of heavy metals and their probable ecological risks. The results revealed high environmental risk of Cd due to higher availability in the exchangeable fraction (21%) and a considerable portion in the carbonate bound fraction due to the special affinity towards carbonate and co-precipitation with its minerals. Toxic metals like Cr, Ni, and Cd are of concern, and can occasionally be associated with adverse biological effects. The risk assessment code (RAC) suggests that the highest mobility of Cd poses a higher environmental risk and threat to the aquatic biota, as well.     

Proteomic Analysis of ABCA1-Null Macrophages Reveals a Role for Stomatin-Like Protein-2 in Raft Composition and Toll-Like Receptor Signaling

Lipid raft membrane microdomains organize signaling by many prototypical receptors, including the Toll-like receptors (TLRs) of the innate immune system. Raft-localization of proteins is widely thought to be regulated by raft cholesterol levels, but this is largely on the basis of studies that have manipulated cell cholesterol using crude and poorly specific chemical tools, such as β-cyclodextrins. To date, there has been no proteome-scale investigation of whether endogenous regulators of intracellular cholesterol trafficking, such as the ATP binding cassette (ABC)A1 lipid efflux transporter, regulate targeting of proteins to rafts. Abca1^−/− macrophages have cholesterol-laden rafts that have been reported to contain increased levels of select proteins, including TLR4, the lipopolysaccharide receptor. Here, using quantitative proteomic profiling, we identified 383 proteins in raft isolates from Abca1^+/+ and Abca1^−/− macrophages. ABCA1 deletion induced wide-ranging changes to the raft proteome. Remarkably, many of these changes were similar to those seen in Abca1^+/+ macrophages after lipopolysaccharide exposure. Stomatin-like protein (SLP)-2, a member of the stomatin-prohibitin-flotillin-HflK/C family of membrane scaffolding proteins, was robustly and specifically increased in Abca1^−/− rafts. Pursuing SLP-2 function, we found that rafts of SLP-2-silenced macrophages had markedly abnormal composition. SLP-2 silencing did not compromise ABCA1-dependent cholesterol efflux but reduced macrophage responsiveness to multiple TLR ligands. This was associated with reduced raft levels of the TLR co-receptor, CD14, and defective lipopolysaccharide-induced recruitment of the common TLR adaptor, MyD88, to rafts. Taken together, we show that the lipid transporter ABCA1 regulates the protein repertoire of rafts and identify SLP-2 as an ABCA1-dependent regulator of raft composition and of the innate immune response.Lipid rafts are cholesterol-enriched membrane microdomains, thought to be present in all cells, that concentrate and organize cell-surface signal transduction events in several signaling cascades, including those of the Toll-like receptors (TLRs) (1). The selectivity of rafts for particular proteins, and, consequently, the signal strength of pathways initiating from ligated raft-resident receptors, are thought to derive in large part from the high cholesterol content of raft microdomains (2–4). In vitro, altering raft cholesterol of living cells downward or upward with chemical tools (e.g. cyclodextrins) leads to parallel changes in raft protein abundance (3, 4). The relevance of cholesterol-driven alterations in the raft proteome to disease is suggested by reports that hypercholesterolemia cholesterol-loads macrophage rafts and amplifies their responsiveness to lipopolysaccharide (LPS) (3, 4). Proteomic strategies have recently been applied to raft isolates from a variety of cell types, aiming to better understand the identity of proteins tonically present in rafts, as well as proteins dynamically recruited to rafts upon cell stimulation (2, 5–8). To date, however, most reports have used cell lines of uncertain physiological relevance. In addition, although raft cholesterol levels are regulated in vivo by intracellular cholesterol trafficking (1), no reports to date have sought to define how the raft proteome is physiologically regulated by cholesterol trafficking proteins.ATP binding cassette (ABC) A1, a member of the ABC transporter superfamily, plays a key role in regulating levels of cholesterol in macrophages and other cells via promoting efflux of cellular cholesterol to extracellular acceptors, in particular lipid-free apolipoprotein (apo) A-I (9). The importance of ABCA1¹ to human health is clearly illustrated by Tangier disease, a rare ABCA1 mutation syndrome typified by severe HDL deficiency, widespread macrophage foam cells, and premature atherosclerosis (10). In addition, the large number of common ABCA1 polymorphisms that have been associated with human cardiovascular disease (10) suggest a broad-spanning impact of ABCA1 on human health. It remains somewhat controversial whether ABCA1-effluxed cholesterol derives from raft or extra-raft membranes (11). Nonetheless, both human Tangier disease cells and ABCA1-null murine macrophages have been shown to have greatly expanded lipid rafts that contain increased cholesterol and increased TLR4 (12, 13). These changes are associated with enhanced responsiveness to LPS that can be reversed by cholesterol depletion (13–15). Collectively, these findings indicate that ABCA1 may regulate the raft proteome and innate immune response through control of raft cholesterol. However, no proteomic analysis of rafts from ABCA1-deficient cells has been reported to date.Herein, we report a proteomic analysis of raft isolates from naive and LPS-stimulated Abca1^+/+ and Abca1^−/− primary murine macrophages. Unexpectedly, we found that ABCA1 deletion and LPS stimulation induced many similar changes in the raft proteome. Stomatin-like protein 2 (SLP-2), a lesser known member of the stomatin-prohibitin-flotillin-HflK/C (SPFH) family of membrane scaffolding proteins, was unique among SPFH proteins in being robustly up-regulated in rafts of unstimulated Abca1^−/− cells compared with Abca1^+/+ counterparts. We found that rafts of SLP-2 knockdown cells were abnormal, displaying increased binding of cholera toxin subunit B—a probe for the raft-specific ganglioside GM1—but markedly decreased protein, including flotillins-1 and -2, and CD14. Whereas SLP-2 silencing did not compromise ABCA1-dependent cholesterol efflux, it reduced macrophage responsiveness to LPS and multiple additional TLR ligands. Taken together, we report that ABCA1 regulates the macrophage raft proteome and identify SLP-2 as a novel ABCA1-dependent regulator of raft composition that controls the innate immune response.     

Length–weight relationships of 13 fish species from Pahang River,Temerloh district,Pahang, Malaysia

Length–weight relationships (LWRs) are described for 13 fish species from Pahang River, Temerloh district, Pahang, Malaysia. The river serves as a main water body for freshwater aquaculture in the country and also supplies various fishes for local consumption. This is the first record of LWRs for nine fish species and new maximum lengths for three species in fishbase .     

Copper complex derived from <Emphasis Type="Italic">S</Emphasis>-benzyldithiocarbazate and 3-acetylcoumarin induced apoptosis in breast cancer cell

Copper complexes have been widely studied for the anti-tumour application as cancer cells are reported to take up greater amounts of copper than normal cells. Preliminary study revealed that the newly synthesised copper complex [Cu(SBCM)₂] displayed marked anti-proliferative towards triple-negative MDA-MB-231 breast cancer cells. Therefore, Cu(SBCM)₂ has great potential to be developed as an agent for the management of breast cancer. The present study was carried out to investigate the mode of cell death induced by Cu(SBCM)₂ towards MDA-MB-231 breast cancer cells. The inhibitory and morphological changes of MDA-MB-231 cells treated with Cu(SBCM)₂ was determined by using MTT assay and inverted light microscope, respectively. The safety profile of Cu(SBCM)₂ was also evaluated towards human dermal fibroblast (HDF) normal cells. Confirmation of apoptosis and cell cycle arrest were determined by flow cytometry analysis. The expression of p53, Bax, Bcl-2 and MMP2 protein were detected with western blot analysis. Cu(SBCM)₂ significantly inhibited the growth of MDA-MB-231 cells in a dose-dependent manner with GI₅₀ 18.7?±?3.06 µM. Indeed, Cu(SBCM)₂ was less toxic towards HDF normal cells with GI₅₀ 31.8?±?4.0 µM. Morphological study revealed that Cu(SBCM)₂-treated MDA-MB-231 cells experienced cellular shrinkage, membrane blebbing, chromatin condensation and formation of apoptotic bodies, suggesting that Cu(SBCM)₂ induced apoptosis in the cells, which was confirmed by Annexin-V/PI flow cytometry analysis. It was also found that Cu(SBCM)₂ induced G₂/M phase cell cycle arrest towards MDA-MB-231 cells. The induction of apoptosis and cell cycle arrest in the present study is possibly due to the down-regulation of the mutant p53 and MMP2 protein. In conclusion, Cu(SBCM)₂ can be developed as a targeted therapy for the treatment of triple-negative breast cancer.     

Molecular characterization and pathogenicity of Colletotrichum sp. from guava

Guava (Psidium guajava) fruit is vulnerable to postharvest diseases, such as anthracnose. In the present study, molecular characterisation and pathogenicity of Colletotrichum associated with antharcnose disease of guava fruit were conducted. From anthracnose lesion of guava, 20 isolates were successfully recovered. Based on colony colours, conidia, appressoria and presence or absence of setae, and ITS regions and ß-tubulin gene sequences, the isolates were identified as Colletotrichum gloeosporioides. Phylogenetic analysis based on combined data-sets using neighbour-joining method showed that C. gloeosporioides isolates did not group with C. gloeosporioides epitype strain, and thus the isolates were referred to as C. gloeosporioides species complex or C. gloeosporioides sensu lato. Pathogenicity tests using wounded treatment showed that C. gloeosporioides isolates from guava were pathogenic causing anthracnose on the fruits. The present study showed that C. gloeosporioides sensu lato is the most common species causing antharcnose disease of guava fruit.     

Comparison of the effects between animal-derived trypsin and recombinant trypsin on human skin cells proliferation,gene and protein expression

Animal-derivative free reagents are preferred in skin cell culture for clinical applications. The aim of this study was to compare the performance and effects between animal-derived trypsin and recombinant trypsin for skin cells culture and expansion. Full thickness human skin was digested in 0.6 % collagenase for 6 h to liberate the fibroblasts, followed by treatment with either animal-derived trypsin; Trypsin EDTA (TE) or recombinant trypsin; TrypLE Select (TS) to liberate the keratinocytes. Both keratinocytes and fibroblasts were then culture-expanded until passage 2. Trypsinization for both cell types during culture-expansion was performed using either TE or TS. Total cells yield was determined using a haemocytometer. Expression of collagen type I, collagen type III (Col-III), cytokeratin 10, and cytokeratin 14 genes were quantified via RT-PCR and further confirmed with immunocytochemical staining. The results of our study showed that the total cell yield for both keratinocytes and fibroblasts treated with TE or TS were comparable. RT-PCR showed that expression of skin-specific genes except Col-III was higher in the TS treated group compared to that in the TE group. Expression of proteins specific to the two cell types were confirmed by immunocytochemical staining in both TE and TS groups. In conclusion, the performance of the recombinant trypsin is comparable with the well-established animal-derived trypsin for human skin cell culture expansion in terms of cell yield and expression of specific cellular markers.     

Optimization of culture conditions for glucose oxidase production by a Penicillium chrysogenum SRT 19 strain

The enzyme glucose oxidase (GOD) has been used for a variety of biotechnological applications in food and pharmaceutical industries. In this study, the optimization of extracellular GOD production was carried out in a Penicillium chrysogenum SRT 19 strain isolated from contaminated and decaying cheese samples. Maximum GOD production was attained at pH 6 and 20°C in fermentation broth after 72 h of incubation. The effects of metal ions and sugars were screened for the induction of higher GOD production. The results revealed that glucose and lactose give the highest production of enzyme (0.670 and 0.552 U/mL, respectively) as compared with other sugars (sucrose, cellulose, mannitol and fructose). Out of the seven metal ions studied, CaCO₃ (1.123 U/mL) and FeSO₄ (0.822 U/mL) act as modulators, while MgSO₄ (0.535 U/mL), CuSO₄ (0.498 U/mL), HgCl₂ (0.476 U/mL), ZnSO₄ (0.457 U/mL) and BaSO₄ (0.422 U/mL) yield lower production. The study therefore suggests that a strain of P. chrysogenum SRT 19 can be used as a new strain for GOD production.     

Fatal Outbreak from Consuming Xanthium strumarium Seedlings during Time of Food Scarcity in Northeastern Bangladesh

Background

An outbreak characterized by vomiting and rapid progression to unconsciousness and death was reported in Sylhet Distrct in northeastern Bangladesh following destructive monsoon floods in November 2007.

Methods and Findings

We identified cases presenting to local hospitals and described their clinical signs and symptoms. We interviewed patients and their families to collect illness histories and generate hypotheses about exposures associated with disease. An epidemiological study was conducted in two outbreak villages to investigate risk factors for developing illness. 76 patients were identified from 9 villages; 25% (19/76) died. Common presenting symptoms included vomiting, elevated liver enzymes, and altered mental status. In-depth interviews with 33 cases revealed that 31 (94%) had consumed ghagra shak, an uncultivated plant, in the hours before illness onset. Ghagra shak was consumed as a main meal by villagers due to inaccessibility of other foods following destructive monsoon flooding and rises in global food prices. Persons who ate this plant were 34.2 times more likely (95% CI 10.2 to 115.8, p-value<0.000) than others to develop vomiting and unconsciousness during the outbreak in our multivariate model. Ghagra shak is the local name for Xanthium strumarium, or common cocklebur.

Conclusions

The consumption of Xanthium strumarium seedlings in large quantities, due to inaccessibility of other foods, caused this outbreak. The toxic chemical in the plant, carboxyatratyloside, has been previously described and eating X. strumarium seeds and seedlings has been associated with fatalities in humans and livestock. Unless people are able to meet their nutritional requirements with safe foods, they will continue to be at risk for poor health outcomes beyond undernutrition.     

Detection of Methicillin-Resistant Staphylococcus aureus Using mecA/nuc Genes and Antibiotic Susceptibility Profile of Malaysian Clinical Isolates

The aim of this study is to compare methicillin-resistant Staphylococcus aureus (MRSA) detection methods and to generate antibiogram profile of S. aureus clinical isolates from two teaching hospitals in Malaysia including three reference isolates from American Type Culture Collection (ATCC). The mecA/nuc gene PCR amplification, spot inoculation test and oxacillin disc diffusion test were applied to compare its MRSA detection abilities. No disagreement between the three methods was observed. From 29 bacterial isolates (including the ATCC strains) tested, 19 isolates were confirmed as S. aureus with 14 isolates exhibiting multidrug-resistance. All isolates are still susceptible to vancomycin as indicated by the E-test result. Current biochemical tests are comparable with the molecular detection method for MRSA used in this study while multidrug-resistance traits are present in both MRSA and MSSA clinical isolates. Presently, mupirocin seems to be the best alternative for vancomycin against multidrug-resistant S. aureus infections in Malaysia. Susceptibility profile of 19 S. aureus isolates acquired from two teaching hospitals and ATCC towards 16 selected antibiotics was analyzed and an antibiogram was generated. Findings also indicated resistance against many of the available antibiotics and thus an urgent need to search for alternative antibiotics.