1,720,985 research outputs found
Characterisation of Synthetic Dye Decolourising Genes and their Enzymes Produced by an Endophytic Fungus Marasmius cladophyllus UMAS MS8
Get PDFWide spectrum usage of synthetic dyes particularly by the textile and dyestuff industry has caused serious pollution of rivers and lake due to insufficient treatment of dye containing wastewater by current known wastewater treatment methods. Endophytic fungi were therefore isolated from Melastoma malabathricum (local name: Senduduk) to test for their ability to decolourise synthetic dyes. Screening on agar plate for synthetic dye decolourisation has enabled the identification of an isolate MS8 that is capable of decolourising all the synthetic dye tested. Synthetic dye decolourisation in liquid medium by MS8 further confirmed the ability of the fungus to decolourise both azo and anthraquinone dyes. Comparing the ITS sequence with NCBI GenBank identified the fungus to be Marasmius cladophyllus. Study on the dye decolourising mechanism of M. cladophyllus in liquid medium using RBBR dye showed the fungus degradative capability in decolourising the dye with no dye adsorption on the fungal mycelium. Further ligninolytic enzyme assay revealed that the presence of RBBR dye induced
a 70 folds increase in laccase activity by M. cladophyllus. This laccase enzyme after precipitation by ammonium sulphate can also decolourise 90.2% of RBBR dye, 80.0% of
Methyl red, 59.1% of Congo red and 56.1% of Orange G in just 24 hours thus indicating that laccase is the dye decolourising enzyme
Biodegradation of pentachlorophenol (PCP) using indigenous fungal isolates
Get PDFPentachlorophenol (PCP) is a man made chemical compound that has been used widely as an effective biocide in agriculture and also in the wood industry. Wide spectrum usage of PCP however has caused uncontrolled release of this toxic compound into the environment. Fungi were therefore isolated from xenobiotic contaminated samples in order to evaluate their potential to be used for degradation of this toxic compound
Decolourisation Capabilities of Ligninolytic Enzymes Produced by Marasmius cladophyllus UMAS MS8 on Remazol Brilliant Blue R and Other Azo Dyes
Get PDFMarasmius cladophyllus was examined for its ability to degradatively decolourise the recalcitrant dye Remazol Brilliant Blue R (RBBR) and screened for the production of ligninolytic enzymes using specific substrates. Monitoring dye decolourisation by the decrease in absorbance ratio of A 592/A 500 shows that the decolourisation of RBBR dye was associated with the dye degradation. Marasmius cladophyllus produces laccase and lignin peroxidase in glucose minimal liquid medium containing RBBR. Both enzyme activities were increased, with laccase activity recorded 70 times higher reaching up to 390 U L-1 on day 12. Further in vitro RBBR dye decolourisation using the culture medium shows that laccase activity was correlated with the dye decolourisation. Fresh RBBR dye continuously supplemented into the decolourised culture medium was further decolourised much faster in the subsequent round of the RBBR dye decolourisation. In vitro dye decolourisation using the crude laccase not only decolourised 76% of RBBR dye in just 19 hours but also decolourised 54% of Orange G and 33% of Congo red at the same period of time without the use of any exogenous mediator. This rapid dye decolourisation ability of the enzymes produced by M. cladophyllus thus suggested its possible application in the bioremediation of dye containing wastewate
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Production and Optimization of Laccase by Marasmius cladohpyllus UMAS MS8 Using Agro–industrial Waste as Substrate
Get PDF: Fungal laccases are preferred due to their high redox potentials and low substrate specificity.
For large–scale enzyme applications, low enzyme yield and high cost of production has remained the
challenge. Therefore, this research investigates the feasibility of utilizing various types of lignocellulosic
agroindustrial waste such as sago “hampas”, rice husk, and empty fruit bunch (EFB) as substrate in the
production of laccase enzyme by endophytic fungus, Marasmius cladohpyllus UMAS MS8 under both
solid–state fermentation (SSF) and submerged fermentation (SmF). The substrate that produces the
highest laccase enzyme either under SSF or SMF will be selected for further optimization. The
optimization parameters include the incubation period, effect of inducer (Remazol Brilliant Blue R
(RBBR) and copper) and supplementation of different nitrogen sources. Among the three agroindustrial
wastes tested as substrate, EFB under SmF was found to be the most ideal substrate and fermentation
bioprocess to produce laccase enzyme as it gives rise to the highest laccase activity of 0.0919 U/g after
12 days of incubation as compared to other substrates either under SSF or SmF. However, both inducer
RBBR and copper had no induction effect on the production of laccase enzyme. While the
supplementation of nitrogen source, peptone better yield on laccase enzyme production by EFB after
12 days of incubation. In conclusion, these shows the potential of EFB as a cost–effective substrate for
laccase enzyme production, offering an alternative use for this common and abundant agro–industrial
by–product
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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