BIOLOGICAL AND CHEMICAL PROPERTIES OF "VERMIWASH", NATURAL PLANT GROWTH SUPPLEMENT FOR TEA, COCONUT AND HORTICULTURAL CROPS

Earthworms have been well exploited in agriculture worldwide inmaximizing crop production for many years. Amongst vermin-technology(Vermitech) practices, Vermiwash (Vw) has shown its field efficacy withmany crops. Vw is the wash of earthworm's celomic fluid and calcareouslayer and the watery extract of the bedding materials, which is known tocontain ample amounts of soluble macro and micronutrients, natural growthhormones, beneficial microbes, vitamins and amino acids etc. andnematicidal properties. However, the attributes to beneficial agronomicvalues of Vw have not yet been scientifically validated fully although thispractice is extensively being expanded in India and Sri Lanka. Therefore, thepresent study investigated the biological and chemical properties of elevensources of Vw resulted from different earthworm species and raw materials indifferent farms in Sri Lanka. Vw was tested as a source for hydroponics forlettuce in comparison with the Albert solution. The efficacy of regular foliarand soil applications of Vw on bush bean (Variety: Top crop), tomato(Variety: Thilina), nursery tea (cultivar: TRI 4071) and coconut (Variety:DxT) was also evaluated in comparison with vermicompost and conventionalchemical inputs in a series of bioassays.The results of analyses revealed varying levels of biological and chemicalproperties of the test samples but within the optimal range for plant growth.Vw exhibited significantly lower levels of N, P, K but was rich in Ca, Mg,Zn, Fe and Mn; pH and CEC were also in the required ranges. Vwsignificantly (p=0.05) influenced the soil microbial biomass althoughindividual microorganisms were not identified; microbial biomass of Vw andcontrol were estimated as 4.95 and 3.20 x 10-3 mg C02/day/25g soilrespectively. Vw proved as a better alternate source to Albert solution forlettuce growth under hydroponic culture. The root length, root and shootbiomass and total leaf area of bush bean were significantly (p=0.05) affectedby Vw application compared to that of vermin-compost and synthetic fertilizer treatments. In nursery tea, Vw application lead to comparativelygreater callusing of tea cuttings but the increase in root formation and shootgrowth was not significant. Vw application boosted growth of coconutseedlings. However, no positive responses were seen with tomato.The data suggested the potential exploitation of Vw in home gardening,indoor and container planting, biodynamic and organic farming etc. as afarmer friendly, culturally sensitive and economically viable natural product.Further work on attributes to plant growth such as determination of growthhormones, different doses and mass production of uniform quality Vw usingdifferent earthworm species and raw materials etc. would strengthen itssustainable use as an alternative growth supplement

Antigenotoxic Studies of Different Substances to Reduce the DNA Damage Induced by Aflatoxin B1 and Ochratoxin A

Mycotoxins are produced mainly by the mycelial structure of filamentous fungi, or more specifically, molds. These secondary metabolites are synthesized during the end of the exponential growth phase and appear to have no biochemical significance in fungal growth and development. The contamination of foods and feeds with mycotoxins is a significant problem for the adverse effects on humans, animals, and crops that result in illnesses and economic losses. The toxic effect of the ingestion of mycotoxins in humans and animals depends on a number of factors including intake levels, duration of exposure, toxin species, mechanisms of action, metabolism, and defense mechanisms. In general, the consumption of contaminated food and feed with mycotoxin induces to neurotoxic, immunosuppressive, teratogenic, mutagenic, and carcinogenic effect in humans and/or animals. The most significant mycotoxins in terms of public health and agronomic perspective include the aflatoxins, ochratoxin A (OTA), trichothecenes, fumonisins, patulin, and the ergot alkaloids. Due to the detrimental effects of these mycotoxins, several strategies have been developed in order to reduce the risk of exposure. These include the degradation, destruction, inactivation or removal of mycotoxins through chemical, physical and biological methods. However, the results obtained with these methods have not been optimal, because they may change the organoleptic characteristics and nutritional values of food. Another alternative strategy to prevent or reduce the toxic effects of mycotoxins is by applying antimutagenic agents. These substances act according to several extra- or intracellular mechanisms, their main goal being to avoid the interaction of mycotoxins with DNA; as a consequence of their action, these agents would inhibit mutagenesis and carcinogenesis. This article reviews the main strategies used to control AFB1 and ochratoxin A and contains an analysis of some antigenotoxic substances that reduce the DNA damage caused by these mycotoxins

Enhancing maintainability of multi-story buildings in Sri Lanka

The research into the issue of maintainability of multi-story buildings in Sri Lanka is still in its adolescent stage. This report summarizes the main deliverables of a research project dealing with maintainability of multi-story buildings using two elements; fa9ade and flat roof, under tropical conditions. Improving the knowledge of maintainability and setting maintainability benchmarks are two key principles of the research framework. In identifying maintainability problems, 26 and 16 numbers of different defects were identified related to facade and flat roof defects respectively. Their causes were identified as faulty designs, inferior construction and ad-hoc maintenance practices. They were taken as maintainability risk factors for both maintainability scoring systems. The existing maintainability scoring system developed by National University of Singapore (NUS-MSS) was tested for its adoptability for multi-story buildings in Sri Lanka due to similarity between environment and buildings profiles in two countries. Statistical /-test was used for the comparison. This model was developed using 13 risk factors related to fa5ade maintainability. These factors are common for maintainability of facades of multi-story buildings here. Further, statistical test results showed that NUS-MSS can be successfully adopted to predict the level of maintainability of fa9ades of multi-story buildings in Sri Lanka A prototype maintainability scoring system for flat roof using the framework of NUS-MSS; on the basis of life cycle costing approach, involving minimum cleaning, repair, replacement and down time, is established using the back propagation neural networks. This system compromised of 12 input risk factors related to flat roof maintainability including building profile, design parameters, choice of materials, quality of construction, maintenance practices, and environment. Low errors of “network” and “generalization” of the network indicated its capability of forecasting the maintainability levels for new designs. Therefore, as a predictive tool, this system would enable owners, designers, facility managers, contractors and any other party with an interest in achieving the most favourable maintainability right from the design/planning stage

Comparative assessment of next-generation sequencing, denaturing gradient gel electrophoresis, clonal restriction fragment length polymorphism and cloning-sequencing as methods for characterizing commercial microbial consortia

Characterization of commercial microbial consortia products for human and environmental health risk assessment is a major challenge for regulatory agencies. As a means to develop an approach to assess the potential environmental risk of these products, research was conducted to compare four genomics methods for characterizing bacterial communities; (i) Denaturing Gradient Gel Electrophoresis (DGGE), (ii) Clonal-Restriction Fragment Length Polymorphism (C/RFLP), (iii) partial 16S rDNA amplification, cloning followed by Sanger sequencing (PRACS) and (iv) Next-Generation Sequencing (NGS) based on Ion Torrent technology. A commercially available microbial consortium, marketed as a remediation agent for degrading petroleum hydrocarbon contamination in soil and water, was assessed. The bacterial composition of the commercial microbial product was characterized using the above four methods. PCR amplification of 16S rDNA was performed targeting the variable region V6 for DGGE, C/RFLP and PRACS and V5 for Ion Torrent sequencing. Ion Torrent technology was shown to be a promising tool for initial screening by detecting the majority of bacteria in the consortium that were also detected by DGGE, C/RFLP and PRACS. Additionally, Ion Torrent sequencing detected some of the bacteria that were claimed to be in the product, while three other methods failed to detect these specific bacteria. However, the relative proportions of the microbial composition detected by Ion Torrent were found to be different from DGGE, C/RFLP and PRACS, which gave comparable results across these three methods. The discrepancy of the Ion Torrent results may be due to the short read length generated by this technique and the targeting of different variable regions on the 16S rRNA gene used in this study. Arcobacter spp. a potential pathogenic bacteria was detected in the product by all methods, which was further confirmed using genus and species-specific PCR, RFLP and DNA-based sequence analyses. However, the viability of Arcobacter spp. was not confirmed. This study suggests that a combination of two or more methods may be required to ascertain the microbial constituents of a commercial microbial consortium reliably and for the presence of potentially human pathogenic contaminants.Peer reviewed: YesNRC publication: Ye