A comparison of the antioxidant properties and total phenolic content in a Diatom, Chaetoceros sp. and a green microalga, Nannochloropsis sp.

The aquaculture industry commonly makes use of microalgae as live feed. Chaetoceros sp., a diatom, and Nannochloropsis sp., a unicellular green microalga, have both been reported to contain a substantial amount of polyunsaturated fatty acids and carotenoids. Their potential as natural sources of antioxidants has gained recent attention. This study focuses on determining the antioxidant properties of the different solvent extracts, namely hexane, dichloromethane, chloroform and methanol, from both microalgae. The evaluation of antioxidant capacities was done by Folin-ciocalteu, 1,1-diphenyl-2-picrylhydrazyl radical-scavenging, metal chelating, nitro-blue tetrazolium reduction and ferric-reducing antioxidant power assay. Results showed that the non-polar solvent extracts from the diatom were highest in antioxidant power, whereas both polar and non-polar solvent extracts of green microalgae showed good antioxidant potential. In general, Chaetoceros sp. had higher antioxidant capacities than Nannochloropsis sp. This study suggests that different solvent extracts contain different potential antioxidant compounds able to scavenge different types of free radicals

Crude ethyl acetate extract of marine microalga, Chaetoceros calcitrans, induces Apoptosis in MDA-MB-231 breast cancer cells

Background: Marine brown diatom Chaetoceros calcitrans and green microalga Nannochloropsis oculata are beneficial materials for various applications in the food, nutraceutical, pharmaceutical and cosmeceutical industries. Objective: This study investigated cytotoxicity of different crude solvent extracts from C. calcitrans and N. oculata against various cancer cell lines. Materials and Methods: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was carried out to screen the cytotoxic effects of hexane (Hex), dichloromethane (DCM), ethyl acetate, and methanol extract from C. calcitrans and N. oculata toward various cancer cell lines. Flow cytometry cell cycle was used to determine the cell cycle arrest while the mode of cell death was investigated through acridine orange/propidium iodide (AOPI) staining, Annexin V-Fluorescein Isothiocyanate (FITC) and Terminal deoxynucleotidyl transferase-mediated d-UTP Nick End Labeling (TUNEL) assays. Expression profile of apoptotic and proliferative-related genes was then determined using the multiplex gene expression profiler (GeXP). Results: Crude ethyl acetate (CEA) extract of C. calcitrans inhibited growth of MDA-MB-231 cells, with IC 50 of 60 μg/mL after 72 h of treatment. Further studies were conducted to determine the mode of cell death at various concentrations of this extract: 30, 60 and 120 μg/mL. The mode of cell death was mainly apoptosis as shown through apoptosis determination test. The expression data from GeXP showed that caspase-4 was upregulated while B-cell leukemia/lymphoma 2(Bcl-2) was down regulated. Thus, caspase-4 induction endoplasmic reticulum death pathway is believed to be one of the mechanisms underlying the induction of apoptosis while Bcl-2 induced S and G2/M cell cycle phase arrest in MDA-MB-231 cells. Conclusion: CEA extract of C. calcitrans showed the highest cytotoxicity on MDA-MB-231 via apoptosis

Antioxidant and cytotoxic effects of crude extract from a diatom, Chaetoceros calcitrans and green alga, Nannachloropsis oculata

There is a growing trend in research focusing on marine microorganisms such as sponges, seaweeds and micro-algae as a potential source of bioactive compounds. In Malaysia, microalgae are widely used as live feed in shrimp and fish hatcheries. The nutrient-rich source of marine microalgae gives a promising potential to explore its new biomedical applications. This study was carried out to investigate the antioxidant capacity and cytotoxic effects of different polarities of crude solvent extracts namely hexane, dichloromethane, ethyl acetate and methanol from a diatom, Chaetoceros calcitrans and a green alga, Nannochloropsis oculata. The antioxidant properties were determined by 1, 1-diphenyl-2-picrylhrazyl (DPPH) radical-scavenging, ferric-reducing antioxidant power (FRAP), ferrous-ion chelating and folin assays. Results revealed that crude ethyl acetate (EA) extract of C calcitrans contained the highest total phenolic content (3775.67 ± 0.08 mg gallic acid equivalent/g dried extract) and DPPH radical scavenging power (3722.93 ± 2.98 mg Trolox equivalent/g dried extract). The antioxidant activities of extracts from N. oculata were lower compared to the extract from C. calcitrans, except for EA extract of C. calcitrans showed the highest chelating power compared to others. MTT assay was used to determine the cytotoxic properties of crude solvent extracts from C. calcitrans and N. oculata towards various cancer cell lines. Results showed that EA extract of C. calcitrans significantly inhibited the growth of MDA-MB-231 cells among the cancer cell lines tested, with IC50 60 μg/mL only after 72 hours treatment period. Thus, EA extract of C. calcitrans was used in further assay to determine the mode of cell death with three different concentrations : 30 (½ IC50), 60 (IC50) and 120 (2x IC50) μg/mL for 72 hours treatment. In the cell cycle with flow cytometry analysis, EA extract of C. calcitrans arrested the cell cycle of MDA-MB-231 cells at G2/M phase when treated with 60 μg/mL. However, when cells were treated with low concentration (30 μg/mL) of EA extract, significant growth arrest was occurred at G1 phase. Apoptosis was induced when the concentration was increased to 120 μg/mL. The mode of cell death was mainly apoptosis, which was proven by acridine orange/propidium iodide (AO/PI) dual staining method, Annexin V-FITC and DNA fragmentation (TUNEL) assays. Morphology of the treated cells which was observed through AO/PI staining method showed the presence of blebbing cells, chromatin condensation and DNA fragmentation as well as intake of some PI stain, proving that apoptosis has occurred. Early apoptosis was analysed by Annexin V-FITC apoptosis test and DNA fragmentation test showed that DNA was cleaved into fragments. These results indicated the presence of apoptotic cells increased with increasing concentration of the extract. The changes of expression level of apoptotic, and proliferative-related genes caused by EA extracts of C. calcitrans were profiled using multiplex gene expression profiler (GeXP). Cells treated with EA extract for 6, 12 and 24 hours did not show significant changes in the expression levels of most of the pro-apoptotic genes. The expression of pro-apoptotic genes of the cells treated for 48 hours with low concentration (30 μg/mL) of the extract was highly up-regulated. However, the expression level was down-regulated when treated with high concentration of EA extract (120 μg/mL). At 72 hours of treatment period, most of the pro-apoptotic genes especially caspases related genes such as caspases-3, -4, -9, BAK1 and p21 were found to be up-regulated. Conversely, genes that involved in p53 network especially Bax and ING3 as well as anti-apoptotic (Bcl-2) were found to be downregulated. These findings provided some mechanisms of EA extract of C. calcitrans-induced apoptosis in the human breast cancer cells via the caspases induction pathway. In conclusion, C. calcitrans is more cytotoxic compared to N. oculata (solvent extracts). EA extract of C. calcitrans showed the best antioxidant activities and cytotoxicity compared to others, and induced apoptosis in MDA-MB-231 cells. The induction of apoptosis involved important pro-apoptotic genes : p21, casp-3, -4, -9 and Bak1

Development of AGV as test bed for fault detection

Modern machines are still susceptible to faults and breakdown. On the onset of Industry 4.0, machines are equipped with various sensors. This paper describes the development of an (Automated Guided Vehicle) AGV to be used as a test bed to simulate fault condition and generate sensor data which can be used to generate fault detecting models. The AGV is a two wheels diiferential drive mobile robot with motor on each wheel. The AGV is controlled by a microcontroller board connected to a Single Board Computer (SBC). Sensors are installed to monitor the performance of the AGV and the data generated by these sensors are logged to the SBC. The AGV and its sensors are tested. The AGV is functional, can simulate simple fault and fault detection

Automated guided vehicle robot localization with sensor fusion

Robot localization is vital for the operation of an automated guided vehicle (AGV) but is susceptible to problems such as wheel slip. With more sensors fused together, the more environmental information can be collected by the AGV, which helps with the localization of AGV. Inertial measurement unit (IMU) and global positioning unit (GPS) are usually implemented to improve robot localization but are susceptible to noise and are effective outdoors. Indoors, however, are more suitable with light detection and ranging (lidar) device. This paper implements extended Kalman filter (EKF) and unscented Kalman filter (UKF) for robot localization on AGV. AGV localization was tested with EKF and UKF on three different test tracks with different turn conditions. The performance of the EKF and UKF was compared to each other. Different sensors were implemented along with sensor fusion. UKF generates better odometry estimation than EKF with 24.07% better accuracy. With the usage of lidar, wheel slip was compensated

Extracts from microalgae for use in cancer treatment

The present invention relates to crude extracts derived from the microalgae Chaetoceros calcitrans prepared by the use of ethanol or ethyl acetate, which are effective in the treatment, prevention and/or delay of progression of a proliferative disease. Preferably the extracts of the present invention are for use in the treatment, prevention and/or delay of progression of cancer, such as breast cancer. The invention furthermore describes medicaments and pharmaceutical compositions comprising the inventive extracts of Chaetoceros calcitrans. Also method for preparing extracts of Chaetoceros calcitrans are provided, which include the use of solvents, such as ethanol and ethyl acetate

Molecular characterisation and pathotyping of recently isolated Newcastle disease virus isolates based on F protein’s cleavage site

Intensive vaccine programs have been implemented in many countries including Malaysia, but Newcastle disease virus (NDV) outbreaks have occurred, even in well-vaccinated farms. Hence, the present study was aimed to characterize five NDV isolates obtained from NDV vaccinated broiler farms in 2011 based on sequence and phylogenetic analysis of partial fusion gene. All the isolated NDV strains showed that they are categorized as velogenic NDV based on the presence of multi-basic protease cleavage sites, 112RRRKRF117. In addition, phylogenetic analysis showed that the isolates can classified under the genotype VII, subgenotype VIId