Identification of Biomarkers Associated with Phyllosticta citricarpa Tolerance.

Citrus black spot (CBS) is a fungal disease caused by Phyllosticta citricarpa Kiely, (McAlpine Van der Aa), with most cultivars being susceptible to infection. Currently, disease control is based on the application of protective fungicides, which is restricted due to resistance, health and environmental concerns. Although using natural products for disease management is gaining momentum, more advances are required. This study obtained the metabolic profiles of the essential oil and cuticular waxes of two citrus cultivars with a varying susceptibility to CBS infection using gas chromatography-mass spectrometry. A multivariate data analysis identified possible biomarker compounds that contributed to the difference in susceptibility between the two cultivars. Several identified biomarkers were tested in vitro for their antifungal properties against P. citricarpa. Two biomarkers, propanoic acid and linalool, were able to completely inhibit pathogen growth at 750 mg/L and 2000 mg/L, respectively.

Application of coal fly ash for trace metal adsorption from wastewater: A review.

Environmental pollution has become a global issue due to continuing anthropogenic activities that result in the production of enormous amounts of waste and the subsequent release of hazardous trace metals. The increasing levels of trace metals in the environment must be monitored regularly and reduced to prevent contamination of food chain. Numerous conventional technologies that are widely used for the removal of trace metals from environmental matrices have many drawbacks. Currently, the preferred method to remove trace metal ions is the adsorption process, which normally uses adsorbents. This review investigated the applications of coal fly ash (CFA) as a cost-effective adsorbent and the role it plays in the improved properties of nanomaterials that are used for treatment of trace metals in water. The use of CFA and its role in chemical modification processes results to high removal efficiency of trace metals. CFA is a by-product of coal combustion which is available in abundance and therefore its use is not only beneficial in water treatment processes, but also reduce the burden of solid waste disposal.

Investigation into the role of phenolic compounds in the protection of citrus against Phyllosticta citricarpa.

INTRODUCTION: The use of chemical fungicides to combat disease has made a substantial contribution to food quality and security. Nonetheless, their applications have been limited due to environmental and health concerns, unaffordability, and the fact that pathogens have acquired resistance to some of these fungicides. Alternative eco-friendly and safe control methods should be explored. The current study investigated the influence of citrus rind phenolic compounds against Phyllosticta citricarpa infection by metabolic profiling of two citrus cultivars with varying degrees of susceptibility to infection. METHODS: Chromatographic data obtained by Ultra Performance Liquid Chromatography-Mass Spectrometry (UPLC) was subjected to multivariate data analysis to identify biomarkers associated with the tolerant cultivar. The identified biomarkers were tested in vitro against P. citricarpa. RESULTS: Seville oranges, a tolerant cultivar, displayed higher levels of phenolic content and lower total sugar content, that are both associated with lower susceptibility to citrus black spot infection. The generated Principal Component Analysis (PCA) and Orthogonal Projection to Latent Structures-Discriminant Analysis (OPLS-DA) models gave an overview of the data set and identified components that may be responsible for the differences in susceptibility between the two cultivars. Candidate biomarkers associated with tolerance were identified as naringin, neoeriocitrin, bruteiridin, melitidin, and lucenin-2. CONCLUSION: Naringin, a major candidate biomarker was able to inhibit the growth of the pathogen at 10 000 ppm.

Characterisation of Sclerocarya birrea (marula) seed oil and investigation of the geographical origin by applying similarity calculations, differential NMR and hierarchical cluster analysis.

INTRODUCTION: The marula fruit is an important indigenous African fruit since various commercial products are produced from the pulp and the seed oil. The increased demand requires methods for authentication, quality control and determination of geographical origin. OBJECTIVE: The study aimed to establish a fast and reliable method for characterisation and authentication of marula seed oil. Furthermore, to identify marker compounds that can distinguish marula seed oils from other commercial oils and indicate regional differences. MATERIALS AND METHODS: Metabolic profiling of 44 commercial marula seed oils was performed using proton nuclear magnetic resonance (1 H NMR). For rapid classification similarity calculations were compared with principal component analysis. Differential NMR was used to determine marker compounds. RESULTS: Marula seed oil was found to be similar to macadamia and olive oils and was distinguished from these oils by the detection of minor components. Marula seed oil is differentiated from the other two oils by the absence of α-linolenic acid, relatively high levels of monoglycerides and diglycerides, and an approximately 1:1 ratio of 1,2- and 1,3-diglycerides. When comparing marula seed oils from various regions using hierarchical cluster analysis, clustering of the marula seed oils from Namibia and Zimbabwe was observed and was related to the quantities of linoleic acid and monoglycerides and diglycerides. Some samples displayed deviations in their composition which might indicate adulteration or contamination during the production process. CONCLUSION: The study demonstrates the potential of NMR as a tool in the quality control of marula seed oil. This technique requires very little sample preparation, circumvents derivatisation of the oil components with fast run-times. In addition, samples with chemical profiles that differ from the general signature profile can easily be identified.

Chemical characterization and toxicity evaluation of fungal pigments for potential application in food, phamarceutical and agricultural industries.

Concerns associated with the use of synthetic colourants backs the demand for natural colourants. Thus, the current study aimed at characterizing crude fungal pigments produced by Penicillium multicolour, P. canescens, Talaromyces verruculosus, Fusarium solani and P. herquie. This included their antioxidant and antimicrobial properties together with acute toxicity evaluation on zebrafish embryos. The identification of pigment compounds was achieved through MS and IR data. The study demonstrated a substantial radical scavenging activity of extracts ranging from 65.49 to 74.46%, close to that of ascorbic acid (89.21%). Penicillium canescens and F. solani exhibited a strong antimicrobial activity against Escherichia coli and Enterococcus aerogenes and Salmonella typhi, Staphylococcus aureus and Bacillus cereus at MIC values ranging from 1.5 to 2.5 mg/mL. However, some levels of toxicity were observed for all extracts at a concentration range of 3-5 mg/mL. Pigment by P. multicolour, T. verruculosus and F. solani were tentatively identified through IR and MS data as sclerotiorin (yellow), rubropunctamine (red) and bostrycoidin (red). In conclusion, the study demonstrates a market potential of filamentous fungi pigments due to their antioxidant, antimicrobial activities, and prominent colours. Although there are some toxicity concerns, further tests must be done using molecular docking, albino mice and cell linings.

Toxicity of polychlorinated biphenyls in aquatic environments - A review.

The assessment of polychlorinated biphenyls (PCBs) and their congeners resulting from the pollution of all environmental media is inherently related to its persistence and ubiquitous nature. In principle, determination of this class of contaminants are limited to the determination of their concentrations in the various environmental matrices. For solving many problems in this context, knowledge of the emission sources of PCBs, transport pathways, and sites of contamination and biomagnification is of great benefit to scientists and researchers, as well as many regulatory organizations. By far the largest amounts of PCBs, regardless of their discharged points, end up in the soil, sediment and finally in different aquatic environments. By reviewing relevant published materials, the source of origin of PCBs in the environment particularly from different pollution point sources, it is possible to obtain useful information on the nature of different materials that are sources of PCBs, or their concentrations and their toxicity or health effects and how they can be removed from contaminated media. This review focuses on the sources of PCBs in aquatic environments and critically reviews the toxicity of PCBs in aquatic animals and plants. The review also assesses the toxicity equivalency factors (TEFs) of PCBs providing valuable knowledge to other scientists and researchers that enables regulatory laws to be formulated based on selective determination of concentrations regarding their maximum permissible limits (MPLs) allowed. This review also supplies a pool of valuable information useful for designing decontamination technologies for PCBs in media like soil, sediment, and wastewaters.

Flavonoids from the Genus Euphorbia: Isolation, Structure, Pharmacological Activities and Structure-Activity Relationships.

Plants of the genus Euphorbia are widely distributed across temperate, tropical and subtropical regions of South America, Asia and Africa with established Ayurvedic, Chinese and Malay ethnomedical records. The present review reports the isolation, occurrence, phytochemistry, biological properties, therapeutic potential and structure-activity relationship of Euphorbia flavonoids for the period covering 2000-2020, while identifying potential areas for future studies aimed at development of new therapeutic agents from these plants. The findings suggest that the extracts and isolated flavonoids possess anticancer, antiproliferative, antimalarial, antibacterial, anti-venom, anti-inflammatory, anti-hepatitis and antioxidant properties and have different mechanisms of action against cancer cells. Of the investigated species, over 80 different types of flavonoids have been isolated to date. Most of the isolated flavonoids were flavonols and comprised simple O-substitution patterns, C-methylation and prenylation. Others had a glycoside, glycosidic linkages and a carbohydrate attached at either C-3 or C-7, and were designated as d-glucose, l-rhamnose or glucorhamnose. The structure-activity relationship studies showed that methylation of the hydroxyl groups on C-3 or C-7 reduces the activities while glycosylation loses the activity and that the parent skeletal structure is essential in retaining the activity. These constituents can therefore offer potential alternative scaffolds towards development of new Euphorbia-based therapeutic agents.

Occurrence, distribution, spatio-temporal variability and source identification of n-alkanes and polycyclic aromatic hydrocarbons in water and sediment from Loskop dam, South Africa.

In this study, the spatial and temporal variations in the levels of C8-C40 n-alkanes and 18 polycyclic aromatic hydrocarbons (PAHs) in water and sediment from Loskop Dam (Mpumalanga Province South Africa), were investigated between 2015 and 2017. In addition, their sources, which have not been well defined, were also studied over the period. This water body is sourced from a historically contaminated water body, the Olifants River, which flows through areas where a range of industrial and agricultural activities take place. Mass crocodile and fish mortalities have been recorded in this aquatic system, and contamination by organic pollutants were highlighted as a contributing factor. The total average n-alkane concentrations in water and sediments ranged from 0.574±00811 to 18.8±1.39 µg/L and 4760±243 to 30700±906 µg/kg, respectively. Similarly, PAHs were detected at total average concentrations of between 0.150±00494 and 49.8±6.86 µg/L in water and 61.6±5.95 to 2618±300 µg/kg. n-Alkane and PAH diagnostic ratios indicated a mixture of sources of these compounds, attributed to terrestrial, submerged and floating plant material, as well as petrogenic and pyrogenic combustion. Inlet, middle and upper segment site clustering was observed with non-metric multidimensional scaling (NMDS) and hierarchical cluster analysis (HCA), mainly driven by the prevalence of PAHs at the inlet sites and n-alkanes in the upper reaches. By using indicator compounds, the sources of contamination could be predicted. The strategy described here can be applied to any water body for continuous long-term monitoring of pollutant levels and to identify sources attributing to water pollution.