Gynura procumbens or longevity spinach plant is a type of medicinal plant that
distributes widely in Southeast Asia including Malaysia. G. procumbens is
commonly called as pokok Sambung Nyawa, Sabong Nyawa, Akar Sebiak, or
Kecam Akar by Malaysians; and often consumed as ulam or salad. Thus, there
might be several microorganisms particularly bacteria that still inhabiting the
leaves. Intensive studies on the therapeutic potential of G. procumbens have
indeed been carried out over time. However, studies focusing on the link between
medicinal plants and bacteria that inhabit the plant specifically epiphytic bacteria
on the leaf surface have yet to be fully appreciated. Besides, only one available
study on the diversity of bacteria inhabiting the phyllosphere was available
showing the lack of related studies. Thus, this study aimed to identify epiphytic
bacteria of G. procumbens leaves based on morphology through Gram-staining
and genetics using 16S ribosomal RNA gene sequencing; and to determine the
possible contribution of the bacteria to the medicinal properties of G. procumbens
by further readings. The findings from this research suggested the presence of
five species of bacteria i.e. Bacillus subtilis, Bacillus amyloliquefaciens, Pantoea
agglomerans, Sphingomonas melonis, and Burkholderia cepacia. From further
readings, it is known that some of the bacterial species have the potentials towards
medicinal applications. Also, it is hypothesised that the production of some
secondary metabolites in the plant might be due to the presence of the bacteria.
This study aimed to resolve the taxonomic status of a morphologically undetermined sea cucumber species of order Apodida
from Malaysia (GenBank accession no.: FJ223867) using partial 16S mitochondrial rRNA gene sequences and subsequently
to determine the validity of morphological taxonomy of Holothuria species into its current subgenera. The undetermined
species clustered with all taxa of Holothuria in previous study. Phylogenetic analyses using maximum parsimony and
Bayesian methods suggest that the undetermined species was genetically closer to Holothuria (Lessonothuria) pardalis and
Holothuria (Acanthotrapeza) coluber; and its position in both phylogenetic trees further suggests its status as a Holothuria
taxon. Subgenera of Holothuria, Merthensiothuria and Metriatyla are monophyletic with strong bootstrap supports and
posterior probabilities of clades, thus strengthening their morphological taxonomies. Nonetheless, the non-monophyly of
subgenera of Halodeima, Microthele and Platyperona suggests a requirement for their taxonomic revisions using integrative
taxonomy. The status of Holothuria (Halodeima) edulis subgroups in the maximum parsimony and Bayesian trees is
indistinct and further taxonomic revisions are necessary. In terms of sister relationship, both phylogenetic trees suggest
that subgenus Holothuria is a sister taxon of subgenus Roweothuria while the other sister relationships were unclear due
to the undetermined species, paraphyly and polyphyly of a number of subgenera. Further studies with more specimens of
genus Holothuria from broader geographical locations and various mtDNA genes along with morphological approaches
may facilitate to provide better insights into the molecular phylogeny of subgenera of Holothuria.
Streptococcus pneumoniae (S. pneumoniae) is a gram-positive diplococci belonging to the genus Streptococcus and it is a well-studied pathogenic bacterium. Pneumococcal diseases such as otitis media, pneumonia, sepsis and meningitis caused by pathogenic strains of S. pneumoniae still brought significant mortality and morbidity worldwide. The pathogenicity of S. pneumoniae is exerted by various virulence factors and one of it is the enzyme hyaluronate lyase. Hyaluronate lyase plays a major role in
the invasive capability of S. pneumoniae. Its mechanism of action and crystallographic
structure have been determinedbut its regulatory mechanism is still poorly understood.
Drawing connections between the nutritional behaviour and invasive property of S.
pneumoniae, CodY regulator is hypothesized as a potential hyaluronate lyase regulator.
This work was aimed to construct CodY deficient mutant of S. pneumoniae to form
foundational work for the study of CodY regulatory effect on hyaluronate lyase.
Pigment-producing microorganisms have become a main focus due to the search
of food-grade microbial pigments for natural food colourant industry. Therefore,
this study aimed to isolate and genetically identify bacteria including pigmentproducing
bacterial strains associated with the tentacles of Holothuria
(Lessonothuria) pardalis (Selenka 1867) from Pulau Tinggi, Johor.
Morphological characteristics of bacteria based on Gram staining were observed
using a digital compound microscope. Partial 16S ribosomal RNA (rRNA) gene
sequencing was also incorporated to support the morphological approach. A
number of six partial gene sequences of non-protein coding 16S rRNA were
obtained and the Basic Local Alignment Search Tool (BLAST) analysis
suggested the presence of three known bacteria species from the genera of
Pseudomonas, Chryseobacterium and Klebsiella. The neighbourhood-joining
method and Maximum Likelihood method used in the phylogenetic analysis
supported the identification and classification of the bacteria species. Among the
bacterial isolates, only strain B14 identified as Chryseobacterium sp. produced
pigment i.e. orange pigment. The highest point of cell density of
Chryseobacterium sp. was recorded at 16 hours. However, further analysis is
needed to confirm the pigment characterisation and the potential of this pigment
to be exploited as natural colourant in the food industry.
Burkholderia pseudomallei is the causative agent of melioidosis, an
infectious disease endemic in Southeast Asia and northern Australia. Cases have been
reported in Pahang, Johor Bahru and Kedah. The disease is difficult to combat as B.
pseudomallei has shown resistance to various antibiotics and much is still not understood
about its pathogenicity. It is suggested that investigating the bacterium hypothetical
proteins may provide potential new targets for the development of antimicrobials. The
gene of interest in this study, BPSL2774, encoding BPSL2774 hypothetical protein, is a
target gene that was predicted as essential using transposon-directed insertion site
sequencing technique (TraDIS). We aimed to express and purify soluble GST-tagged
BPSL2774 protein at sufficient concentration for future functional assays. (Copied from article).
Holothuria (Mertensiothuria) leucospilota (Brandt 1835), white threads fish or locally known as bat puntil is currently considered as the most abundant sea cucumber species in Malaysia. This study aimed to generate the genetic profile of H. leucospilota from Malaysia and then to determine the phylogenetic relationship between H. leucospilota and other members of genus Holothuria using partial sequences of cytochrome c oxidase I (COI) mitochondrial DNA (mtDNA) gene. In this study, specimens of H. leucospilota were collected from Intan Besar Island, Langkawi, Kedah Darul Aman in the west coast of Peninsular Malaysia. Three main methods namely neighbour joining, maximum parsimony and maximum likelihood were used for the phylogenetic tree reconstruction. Tree topologies showed that H. leucospilota has its own monophyletic clade clearly distinct from the other species. The pairwise genetic distance calculated further supported these findings. In addition, the results also should that the COI mtDNA gene is capable to unravel the phylogenetic relationship of H. leucospilota.
Nursyamfarhani Akashah, Siti Najihah Solehin, Marsheilla Lia Janing, Nur Aina Yusra Manap, Nor Shahida Ab Rahman, Muhammad Abdul Latiff Abu Bakar, et al.
Sea cucumber or locally known as gamat and timun laut is a well-known attraction
of Pulau Langkawi, Kedah, Malaysia. Not only limited to Pulau Langkawi, sea
cucumber can also be found in other coastal water areas of Malaysia. However,
the species richness and genetic diversity of sea cucumber in Pulau Tinggi, Johor
is still unknown to the marine scientific communities, especially for Holothuria
(Mertensiothuria) leucospilota, the most dominant species in Malaysia.
Therefore, this study aimed to generate DNA barcodes of H. leucospilota from
Pulau Tinggi. Protein-coding cytochrome c oxidase 1 (CO1) mtDNA gene was
used as it is commonly and widely used for molecular species identification via
DNA barcoding. Polymerase chain reaction (PCR) and DNA sequencing were
incorporated to generate the DNA barcodes of CO1 mtDNA gene. The BLAST
program confirmed the species status of the sea cucumber specimens as H.
leuscospilota or locally known as bat puntil or white threads fish. The application
for GenBank, NCBI, U.S. National Library of Medicine registration was
successfully accepted on October 17, 2019 with accession numbers of MN580537
and MN580538). The phylogenetic trees i.e neighbor joining tree (NJ, distancebased
method), maximum parsimony tree (MP, character-based method) and
maximum likehood tree (ML, character-based method) reconstructed using
MEGA X software version 10.0.5 (BETA) further supported the species status of
the sea cucumber specimens from Pulau Tinggi as H. leuscospilota. This is the
first record of CO1 mtDNA barcodes of H. leuscospilota from Pulau Tinggi,
Johor, Malaysia.