1,721,143 research outputs found
The rising of “Modern Actinobacteria” era
Get PDFThe term “Modern Actinobacteria” (MOD-ACTINO) was coined by a Malaysian Scientist Dr. Lee Learn-Han, who has great expertise and experience in the field of actinobacteria research. MOD-ACTINO is defined as a group of actinobacteria capable of producing compounds that can be explored for modern applications such as development of new drugs and cosmeceutics. MOD-ACTINO members consist of already identified or novel actinobacteria isolated from special environments: mangrove, desert, lake, hot spring, cave, mountain, Arctic and Antarctic regions. These actinobac-teria are valuable sources for various industries which can contribute directly/indirectly towards the improvement in many aspects of our lives.</p
Malaysia’s breakthrough in modern actinobacteria (MOD-ACTINO) drug discovery research
Get PDFActinobacteria are well-known producers of metabolites with medicinal value. The application of actinobacterial compounds has been expanded to other fields, including agriculture, aquaculture, and cosmeceutical. With this, the term “Modern Actinobacteria” (MOD-ACTINO) was first coined by a Malaysian researcher, Associate Professor Dr. Lee Learn Han, to define actinobacteria with modern applications. The present review aims to highlight the MOD-ACTINO research achievements in Malaysia. The Malaysian MOD-ACTINO strains are capable of exerting a wide range of bioactivities such as antimicrobial/anti-MRSA, anticancer, antioxidant, antifungal, and antimalarial. Research on MOD-ACTINO is highly encouraged to harness the benefits of actinobacteria and unravel important metabolites for various applications.</p
Actinobacteria: Prolific Producers of Bioactive Metabolites
No full textThis eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contac
Actinobacteria: Prolific Producers of Bioactive Metabolites
No full textThis eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contac
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
Molecular Profiling and Antibiotic Resistance of Salmonella Enterica Subsp. Enterica Isolated from Indigenous Ulam and Poultry Meat
Get PDFSalmonella enterica subsp. enterica formed the major group that represents nearly
60% of the salmonellae. Salmonella organisms emerged as a public health problem
in many countries as salmonellosis has become the most prevalent foodborne disease
worldwide. It has been estimated that approximately 1.4 million cases were reported
annually in the developed nations such as USA. In Malaysia, of 8,640 cases of food
poisoning reported by the Ministry of Health for the year 1999, 811 (9.4%) were due
to Salmonella. The purpose of this study was to characterize and study Salmonella
enterica subsp. enterica (S. enterica) using multiple antimicrobial resistance and
several molecular typing methods including plasmid profiling, PCR-RFLP, RAPD,
ERIC-PCR and Multiplex PCR on antibiotic resistant gene. The isolate were
recovered from poultry meat (55), four types of indigenous vegetables namely
‘selom’ (Oenanthe stolonifera) (59), ‘pegaga’ (Centella asiatica) (20), ‘kesum’
(Polygonum minus) (41), ‘kangkong’ (Ipomoea aquatica) (14) and processed food
(11).Genomic DNA of the 200 S. enterica isolates belonging to 43 different serovars were
recovered from poultry meat, various indigenous vegetables and processed food was
confirmed by specific and duplex PCR targeting the iroB gene that yielded 443 bp
and 606 bp amplicons. The PCR amplification of iroB gene is a rapid and reliable
method for distinguishing between S. enterica and other bacterial species.
Plasmids of S. enterica varied in sizes from 2 to more than 200 kb. Despite limited
knowledge on their function, their presence is frequently used for strain
differentiation in epidemiological studies. Plasmid profiling on the 200 S. enterica
isolates demonstrated high discriminatory capability for serovars differentiation in
this study that was clustered into 70 groups based on the number and pattern of the
bands.
One of the amplification based techniques used in this study for molecular
characterization was PCR-RFLP that incorporated PCR of iroB1, iroB2 and
restriction digest with BglII and AluI to determine the relatedness of bacterial strains.
Results obtained showed that PCR-RFLP has excellent typeablity but low
discriminatory power due to its inability to produce different banding patterns.
ERIC sequences are short, highly conserved 126 bp non-coding regions found in the
Enterobacteriaceae. Its location in bacterial genomes allows discrimination at the
genus, species and serovars levels. RAPD is an amplification-based technique using
arbitrary primers to detect changes in the DNA sequence at the sites in the genome
and enable the discrimination of samples according to sources and serovars.
Dendrogram of RAPD and ERIC-PCR were analyzed and comparisons made using BioNumerics gel analysis software (Applied Maths, Kortrijk, Belgium). Among the
200 isolates of S. enterica, RAPD with arbitrary primers OPAR02, OPAR17 and
OPAR19 generated 47 clusters and 13 single isolates whereas ERIC-PCR with
primers ERIC-1 and ERIC-2 produced 46 clusters and 12 single isolates at 60%
similarity level with discriminatory index (D) of 0.9726 and 0.9606 respectively.
Composite analysis of RAPD and ERIC-PCR profiling simultaneously produced 50
clusters and 18 single isolates at 60% similarity level with highest discriminatory
index of 0.9824. These results demonstrated that composite analysis of RAPD
(OPAR02, OPAR17 and OPAR19) together with ERIC-PCR are a better tool for
differentiation and characterization of S. enterica as compared to a single method
approach.
The multiplex PCR targeted three different antibiotic resistance genes that was used
to detect TEM, PSE-1 and cmlA/tetR genes segment encoding resistance towards
ampicillin, chloramphenicol and tetracycline, respectively which could reduce labour
and cost in analysis of a large number of isolates.
Subsequently antimicrobial resistance was performed using disc diffusion method
with a selection of 13 different antimicrobial agents. Total of 66 profiles were
generated and multiple antimicrobial resistance (MAR) analysis indicated poultry
meat still remains as the main reservoir for multi drug resistant Salmonella. In
contrast, six isolates from the indigenous vegetables showed the highest MAR index
(0.69). This might be due to animal waste fertilizer, irrigation water, contaminated
container and improper handling of food by human that contributed to be the sources
of Salmonella contamination of vegetables. Further investigations need to be conducted to determine if Salmonella isolates in recovered from indigenous
vegetables were gaining more antimicrobial resistance. The characterization of MAR
enabled the determination of antimicrobial patterns and trends in Salmonella from
poultry meat and indigenous vegetables in Malaysia.
As a conclusion, the results from this study could provide valuable information on
the epidemiology and drug resistance trends of S. enterica, and hence contribute
towards better surveillance and infection control measures as well as improved
public health policy
Novel actinobacteria discovery and biosystematics of bacteria from antarctic soils on Barrientos Island
Get PDFThe Antarctic, one of the most poorly explored areas on Earth has emerged as a prospective region for the discovery of novel bacteria and bioactive metabolites. A total
of 17 soil samples were collected from different areas of Barrientos Island to determine the distribution of bacteria in the soil and the potential of soil bacteria (particularly
Actinobacteria) in producing bioactive secondary metabolites. The Biolog EcoPlate system and RAPD both demonstrated that soils with different types of rookery and
characteristics could affect the soil DNA sequences and soil microbial diversity. The PCR-DGGE used to study the diversity of bacteria, especially Actinobacteria
successfully displayed the diverse types of bacteria found within the soil and also provided estimations of their densities. A total of 96 bacterial strains were isolated using 12 different types of isolation media, 39 strains from phylum Actinobacteria and 57 strains from phyum Proteobacteria. Tests for bioactive secondary metabolites were performed and a total of 15 and 14 isolates of Actinobacteria and Proteobacteria were bioactive. The novel strain, 39T was fully characterized by using the polyphasic
approach and results showed that it have many differences from the other genera in the family Dermacoccaceae on the basis of phylogenetic, chemotaxonomic, phenotypic and
signature nucleotide pattern of the 16S rRNA gene. Therefore, it is suggested that strain 39T be classified as a novel genus in the family Dermacoccaceae, as Barrientosiimonas gen. nov., the type species of which is Barrientosiimonas humi gen. nov., sp. nov. It is
evident from this study that the soil of Barrientos Island is a rich source of taxonomically diverse bacteria, especially Actinobacteria. The wide distribution of these
bacteria in the Antarctic implies that they are endemic and therefore the bio-prospecting of soil bacteria from a wide range of geographic locations like the Antarctic regions
would be of great benefit
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