Tips and tricks: antibacterial assay of plant extracts

Antibacterial study of plant origin has brought tremendous breakthrough in various field vis. medicinal, pharmaceutical and food preservatives. The long and tedious process of identifying the capability of extracts due to the need of selecting of smaller sample particle size, maturity of sample, matrix interference, appropriate solvent polarity, substrate to solvent ratio, extraction technique, and sample storage and temperature promises high turnout of antibacterial capacity. Other consideration for instance extraction temperature, duration time, added process such as sonication, sample pretreatment affect the antibacterial extraction. Solvents used in extraction have bactericidal effect on pathogens tested. Agar diffusion and broth dilution are endpoint methods while descriptive methods involve turbidity assays and inhibition curves are used in antibacterial evaluation. Broth dilution method by spectroscopy instrument involves microscale and macroscale volume up to 250 μL and 1 mL respectively. Soluble concentration equivalent to lower concentration of non-polar extract reduces effect of precipitation in minimum inhibitory concentration (MIC) test. MIC is easily determined by polar extracts since it is immiscible with dimethyl sulfoxide (DMSO) and broth media. Minimum bactericidal concentration (MBC) is identified at higher concentration than MIC. Determination of MIC0, MIC50 and MIC100 can be obtained from turbidity assays. Lethality of pathogens can be established at concentration lower than MIC through inhibition on profile curves. Each test should include negative (solvent and DMSO) and positive (penicillin or tetracycline) measures to support the data analysis. Complementary antibacterial assays are recommended for confirmation of antibacterial properties from plant extracts

In vitro antibacterial activities and composition of Carica papaya cv. Sekaki/Hong Kong peel extracts

Ten solvents were used to extract phytochemicals from the peel of Carica papaya cv. Sekaki/Hong Kong to determine their antibacterial activities. Moderate to clear inhibition on Corynebacterium diphtheriae, Streptococcus pneumoniae, Bacillus subtilis and Clostridium perfringens were obtained from the disk diffusion test out of fourteen pathogens tested. Petroleum ether extract, the most potent extract, showed moderate inhibition towards C. diphtheria and S. pneumoniae at MIC of 5.63 mg/mL and 1.40 mg/mL. Polar solvents gave higher yield, total phenolic and total flavonoid contents than nonpolar solvents. Extract yields were 10.9 to 84.1 mg/g in polar solvents and 3.9 to 20.3 mg/g in non-polar solvents. Twenty eight compounds were identified in petroleum extracts through GC/MS analysis. Among the compounds identified were fatty acids, esters, alkane, tocopherols and sterols. 9,12,15-octadecatrienoic acid was the most abundant compound

Examining the effect of agency cost on capital structure-financial performance nexus: empirical evidence for emerging market

Despite the long history of testing agency theory, it is yet standing undefeated. This study examines the relationship between capital structure and firm performance in an emerging economy, Iraq. Moreover, it seeks to find an answer for the question “does agency cost moderates the relationship between capital structure and financial performance?” in the case of a developing industrial sector. Data was collected from published financial statements from the Iraqi Stock Exchange. The study sample consists of several companies from industrial sector listed on ISX over the period 2004–2020. Firm performance is measured using both accounting data and market indicator. Agency cost is measured through operating expense ratio and asset utilization ratio. Testing for short-term and long-term parameters between groups, pooled mean group estimation method is used for data analysis. The results manifest evidence to support agency theory in explaining the relationship between capital structure and financial performance. Moreover, strong interactions are found indicating that agency cost has a considerable impact on the capital structure and firm performance association, that is, agency cost moderates the relationship between capital structure and firm performance. These results are robust checking various methods and diagnostics checks. These results are key evidence from an emerging country, Iraq to support the agency theory arguments. The results provide significant insights for managers of the sector particularly for the current rapid development in the sector

Comparison of prediction model using spatial discriminant analysis for marine water quality index in mangrove estuarine zones

The prediction models of MWQI in mangrove and estuarine zones were constructed. The 2011–2015 data em- ployed in this study entailed 13 parameters from six monitoring stations in West Malaysia. Spatial discriminant analysis (SDA) had recommended seven significant parameters to develop the MWQI which were DO, TSS, O&G, PO4, Cd, Cr and Zn. These selected parameters were then used to develop prediction models for the MWQI using artificial neural network (ANN) and multiple linear regressions (MLR). The SDA-ANN model had higher R2 value for training (0.9044) and validation (0.7113) results than SDA-MLR model and was chosen as the best model in mangrove estuarine zone. The SDA-ANN model had also demonstrated lower RMSE (5.224) than the SDA-MLR (12.7755). In summary, this work suggested that ANN was an effective tool to compute the MWQ in mangrove estuarine zone and a powerful alternative prediction model as compared to the other modelling methods

Basic Requirements of Laboratory Operation for Halal Analysis

Analysis of halal food requires that the laboratories conductive the tests adhere to international guidelines and standards. Common worldwide guidelines and standards for laboratory include the ‘International Organization for Standardization 17025’ (ISO 17025), the ‘Good Manufacturing Practice’ (GMP), and ‘Good Laboratory Practice’ (GLP). In halal analysis, the laboratory shall comply with ISO 17025, GMP, and ‘Good Hygiene Practice’ (GHP) as stated in the ‘Manual Procedure for Malaysia Halal Certification’ (MPPHM). This article discusses the basic requirements for laboratory practises, specifically for halal analysis. The study compares these international guidelines  with ‘Malaysia Halal Standards’ to demonstrate that these international standards are combined with Islamic practices to produce valid test results using globally recognized best-practices. This promotes confidence in the halal laboratory’s work both nationally and internationally, and will thus improve international trade. Keywords: Halal analysis, ISO 17025, GMP, GLP, laboratory operation

Overcoming triple-negative breast cancer (TNBC) resistance to oncolytic virotherapy by histone deacetylase inhibitor, trichostatin A

"Triple-negative breast cancer (TNBC) is a tumor classification that lack receptors for the hormones estrogen, progesterone and HER2 protein. These malignancies are characterized to be of poor prognosis, refractoriness to conventional therapy and high rates of recurrence. Virotherapy with oncolytic adenovirus (OAd) consists of cancer selective viruses that replicate, spread, and kill cancer cells by oncolysis, without affecting the normal cells."--Introduction

Protease-degradable microgels for protein delivery for vascularization

Degradable hydrogels to deliver bioactive proteins represent an emerging platform for promoting tissue repair and vascularization in various applications. However, implanting these biomaterials requires invasive surgery, which is associated with complications such as inflammation, scarring, and infection. To address these shortcomings, we applied microfluidics-based polymerization to engineer injectable poly(ethylene glycol) microgels of defined size and crosslinked with a protease degradable peptide to allow for triggered release of proteins. The release rate of proteins covalently tethered within the microgel network was tuned by modifying the ratio of degradable to non-degradable crosslinkers, and the released proteins retained full bioactivity. Microgels injected into the dorsum of mice were maintained in the subcutaneous space and degraded within 2 weeks in response to local proteases. Furthermore, controlled release of VEGF from degradable microgels promoted increased vascularization compared to empty microgels or bolus injection of VEGF. Collectively, this study motivates the use of microgels as a viable method for controlled protein delivery in regenerative medicine applications

Variability on particulate matter and meteorology dataset during the hazy period in eastern region of Peninsular Malaysia

This paper provides detail on sequence analysis of hazy days based on eight monitoring stations from three states (Kelantan, Ter- engganu and Pahang) in the eastern region of Peninsular Malaysia. The dataset comprises of 1502 daily mean hazy days that had been measured for a decade. The meteorology data namely wind speed, wind direction, air temperature, relative humidity and particulate matter (PM10) were used to comprehend the variability, and the relationship existed amongst variables. The final dataset consists of a summary descriptive analysis and a boxplot, where all five var- iables were involved, including the minimum, maximum, mean, 1st quartile, median, 3rd quartile and standard deviation are pre- sented. Apart from descriptive analysis, the normality test and histogram were performed as well