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Fulltext Breast Necrosis: a rare case of neglected Phyllodes tumour

Ho, Hui Lian, Ambikapathan, Theiyallen, Nornazirah Azizan, Lee, Li Ping Doreen, Siti Zubaidah Sharif, Firdaus Hayati

Malaysian Journal of Medicine and Health Sciences, 2019;15(1):79-81.
MyJurnal

Phyllodes tumour (PT) of the breast is firstly described in literature as early as 1838. This article reports the youngest recorded case of giant complicated PT and the role of toilet mastectomy as a salvage surgery. A 19-year-old lady presented with a gigantic lump of the left breast for 6 months which was rapidly growing (20 x 20 cm) and complicated with a foul-smelling blackish discoloration of the breast skin and tissues. Toilet mastectomy was performed as a result. The specimen weighed 4.0 kg with histopathological report of the tumor being borderline phyllodes. Herein, we describe a case of PT, who presented with breast necrosis and we discuss its medico-social aspect of it.
Fulltext Blastocystis sp.: waterborne zoonotic organism, a possibility?

Lee LI, Chye TT, Karmacharya BM, Govind SK

Parasit Vectors, 2012;5:130.
PMID: 22741573 DOI: 10.1186/1756-3305-5-130

Blastocystis sp. is a common intestinal parasite found in faecal sample surveys. Several studies have implicated human-to-human, zoonotic and waterborne transmissions by Blastocystis sp. However, there has been no study providing evidence interlinking these three transmissions in a community. We have previously shown a high prevalence of Blastocystis sp. subtype 4 amongst village dwellers in Bahunipati, Nepal, and the present study extends the observation to assess if the same subtype of Blastocystis sp. occurs in animals they rear and rivers they frequent.
Fulltext Pregnancy outcomes in women with non-transfusion dependent thalassaemia (NTDT): A haematology centre experience

Lee BS, Sathar J, Sivapatham L, Lee LI

Malays J Pathol, 2018 Aug;40(2):149-152.
PMID: 30173232 MyJurnal

INTRODUCTION: Non-transfusion dependent thalassaemia (NTDT) is a term used for thalassaemia patients who do not require lifelong regular transfusions for survival. Pregnancy in these women, whether spontaneous or through assisted reproductive technology, represents a challenge for the physician.
MATERIALS AND METHODS: The maternal and foetal outcomes of patients with NTDT followed up in a tertiary haematology centre over 6 months period were studied. A total of 36 pregnancies in 26 pregnant women with NTDT were analysed.
RESULTS: Among these women, all of the pregnancies resulted in successful delivery of singleton live-born neonates. There were four clinically distinct forms of NTDT among these women which include Hb E/β-thalassemia (mild and moderate forms), HbH disease, HbH-Constant Spring, and homozygous δβ-thalassemia. No blood transfusion was needed in 15 of the 36 pregnancies (41.6%). The lowest mean Hb level in which no blood transfusion was given was 8.21 g/dL. The mean of packed-cell units received during pregnancy was 6.95 units per pregnancy. There was no worsening of serum ferritin observed during pregnancy with mean serum ferritin pre- and post-pregnancy of 409.35 ug/L and 418.18 ug/L respectively. The mean gestational age at delivery was 38.6 weeks with no preterm delivery reported. The mean foetal birth weight was 2729 grams. There was no intrauterine growth restriction (IUGR) or congenital malformation. There was a case of small for gestational age (SGA) and a case of oligohydramnios.
CONCLUSION: This study showed that pregnancy was possible, safe and has a favourable outcome in patients with NTDT with multidisciplinary care.
Thermophiles in the genomic era: Biodiversity, science, and applications

Urbieta MS, Donati ER, Chan KG, Shahar S, Sin LL, Goh KM

Biotechnol Adv, 2015 Nov 1;33(6 Pt 1):633-47.
PMID: 25911946 DOI: 10.1016/j.biotechadv.2015.04.007

Thermophiles and hyperthermophiles are present in various regions of the Earth, including volcanic environments, hot springs, mud pots, fumaroles, geysers, coastal thermal springs, and even deep-sea hydrothermal vents. They are also found in man-made environments, such as heated compost facilities, reactors, and spray dryers. Thermophiles, hyperthermophiles, and their bioproducts facilitate various industrial, agricultural, and medicinal applications and offer potential solutions to environmental damages and the demand for biofuels. Intensified efforts to sequence the entire genome of hyperthermophiles and thermophiles are increasing rapidly, as evidenced by the fact that over 120 complete genome sequences of the hyperthermophiles Aquificae, Thermotogae, Crenarchaeota, and Euryarchaeota are now available. In this review, we summarise the major current applications of thermophiles and thermozymes. In addition, emphasis is placed on recent progress in understanding the biodiversity, genomes, transcriptomes, metagenomes, and single-cell sequencing of thermophiles in the genomic era.
Fulltext Characterization of a glucose-tolerant β-glucosidase from Anoxybacillus sp. DT3-1

Chan CS, Sin LL, Chan KG, Shamsir MS, Manan FA, Sani RK, et al.

Biotechnol Biofuels, 2016;9(1):174.
PMID: 27555880 DOI: 10.1186/s13068-016-0587-x

In general, biofuel production involves biomass pretreatment and enzymatic saccharification, followed by the subsequent sugar conversion to biofuel via fermentation. The crucial step in the production of biofuel from biomass is the enzymatic saccharification. Many of the commercial cellulase enzyme cocktails, such as Spezyme(®) CP (Genencor), Acellerase™ 1000 (Genencor), and Celluclast(®) 1.5L (Novozymes), are ineffectively to release free glucose from the pretreated biomass without additional β-glucosidase.
Prevention of influenza during mismatched seasons in older adults with an MF59-adjuvanted quadrivalent influenza vaccine: a randomised, controlled, multicentre, phase 3 efficacy study

Beran J, Reynales H, Poder A, Yu CY, Pitisuttithum P, Yuan LL, et al.

Lancet Infect Dis, 2021 07;21(7):1027-1037.
PMID: 33577767 DOI: 10.1016/S1473-3099(20)30694-0

BACKGROUND: The absolute degree of protection from influenza vaccines in older adults has not been studied since 2001. This study aimed to show the clinical efficacy of an MF59-adjuvanted quadrivalent influenza vaccine (aQIV) in adults 65 years or older compared with adults not vaccinated to prevent influenza.
METHODS: We did a randomised, stratified, observer-blind, controlled, multicentre, phase 3 study at 89 sites in 12 countries in 2016-17 northern hemisphere and 2017 southern hemisphere influenza seasons. We enrolled community-dwelling male and female adults aged 65 years and older who were healthy or had comorbidities that increased their risk of influenza complications. We stratified eligible participants by age (cohorts 65-74 years and ≥75 years) and risk of influenza complications (high and low) and randomly assigned them (1:1) via an interactive response technology to receive either aQIV or a non-influenza comparator vaccine. We masked participants and outcome assessors to the administered vaccine. Personnel administering the vaccines did not participate in endpoint assessment. The primary outcome was absolute vaccine efficacy assessed by RT-PCR-confirmed influenza due to any influenza strain in the overall study population (full analysis set) from day 21 to 180 or the end of the influenza season. Vaccine efficacy was calculated on the basis of a Cox proportional hazard regression model for time to first occurrence of RT-PCR-confirmed influenza due to any strain of influenza. Safety outcomes were assessed in the overall study population. This trial was registered with ClinicalTrials.gov, NCT02587221.
FINDINGS: Northern hemisphere enrolment occurred between Sept 30, 2016, and Feb 28, 2017, and southern hemisphere enrolment between May 26, 2017, and 30 June 30, 2017. aQIV was administered to 3381 participants, who subsequently had 122 (3·6%) RT-PCR-confirmed influenza cases, and the comparator was administered to 3380 participants, who subsequently had 151 (4·5%) influenza cases. The majority, 214 (78·4%) of 273, were caused by influenza A H3N2. Most antigenically characterised isolates were mismatched to the vaccine strain (118 [85%] of 139). Vaccine efficacy was 19·8% (multiplicity-adjusted 95% CI -5·3 to 38·9) against all influenza and 49·9% (-24·0 to 79·8) against antigenically matched strains, when the protocol definition of influenza-like illness was used. The most common local solicited adverse event was injection site pain, reported by 102 (16·3%) of 624 participants in the aQIV group and 71 (11·2%) of 632 of participants in the comparator group. Deaths were evenly distributed; none were considered related to study vaccines. The safety profile for aQIV was similar to previously reported trials.
INTERPRETATION: The prespecified criterion for showing the efficacy of aQIV in older adults was not met during the influenza seasons with high amounts of vaccine strain mismatch. Vaccine efficacy was higher against influenza cases associated with higher fever, which represent more clinically significant disease.
FUNDING: Seqirus UK.
Fulltext Lipase-Secreting Bacillus Species in an Oil-Contaminated Habitat: Promising Strains to Alleviate Oil Pollution

Lee LP, Karbul HM, Citartan M, Gopinath SC, Lakshmipriya T, Tang TH

Biomed Res Int, 2015;2015:820575.
PMID: 26180812 DOI: 10.1155/2015/820575

Lipases are of great interest for different industrial applications due to their diversity and versatility. Among different lipases, microbial lipases are preferable due to their broad substrate specificity, and higher stability with lower production costs compared to the lipases from plants and animals. In the past, a vast number of bacterial species have been reported as potential lipases producers. In this study, the lipases-producing bacterial species were isolated from an oil spillage area in the conventional night market. Isolated species were identified as Bacillus species by biochemical tests which indicate their predominant establishment, and further screened on the agar solid surfaces using lipid and gelatin as the substrates. Out of the ten strains tested, four potential strains were subjected to comparison analysis of the lipolytic versus proteolytic activities. Strain 10 exhibited the highest lipolytic and proteolytic activity. In all the strains, the proteolytic activity is higher than the lipolytic activity except for strain 8, suggesting the possibility for substrate-based extracellular gene induction. The simultaneous secretion of both the lipase and protease is a mean of survival. The isolated bacterial species which harbour both lipase and protease enzymes could render potential industrial-based applications and solve environmental issues.
Fulltext Microbial diversity of thermophiles with biomass deconstruction potential in a foliage-rich hot spring

Lee LS, Goh KM, Chan CS, Annie Tan GY, Yin WF, Chong CS, et al.

Microbiologyopen, 2018 12;7(6):e00615.
PMID: 29602271 DOI: 10.1002/mbo3.615

The ability of thermophilic microorganisms and their enzymes to decompose biomass have attracted attention due to their quick reaction time, thermostability, and decreased risk of contamination. Exploitation of efficient thermostable glycoside hydrolases (GHs) could accelerate the industrialization of biofuels and biochemicals. However, the full spectrum of thermophiles and their enzymes that are important for biomass degradation at high temperatures have not yet been thoroughly studied. We examined a Malaysian Y-shaped Sungai Klah hot spring located within a wooded area. The fallen foliage that formed a thick layer of biomass bed under the heated water of the Y-shaped Sungai Klah hot spring was an ideal environment for the discovery and analysis of microbial biomass decay communities. We sequenced the hypervariable regions of bacterial and archaeal 16S rRNA genes using total community DNA extracted from the hot spring. Data suggested that 25 phyla, 58 classes, 110 orders, 171 families, and 328 genera inhabited this hot spring. Among the detected genera, members of Acidimicrobium, Aeropyrum, Caldilinea, Caldisphaera, Chloracidobacterium, Chloroflexus, Desulfurobacterium, Fervidobacterium, Geobacillus, Meiothermus, Melioribacter, Methanothermococcus, Methanotorris, Roseiflexus, Thermoanaerobacter, Thermoanaerobacterium, Thermoanaerobaculum, and Thermosipho were the main thermophiles containing various GHs that play an important role in cellulose and hemicellulose breakdown. Collectively, the results suggest that the microbial community in this hot spring represents a good source for isolating efficient biomass degrading thermophiles and thermozymes.
Bacterial regulatory RNAs: complexity, function, and putative drug targeting

Cheah HL, Raabe CA, Lee LP, Rozhdestvensky TS, Citartan M, Ahmed SA, et al.

Crit Rev Biochem Mol Biol, 2018 08;53(4):335-355.
PMID: 29793351 DOI: 10.1080/10409238.2018.1473330

Over the past decade, RNA-deep sequencing has uncovered copious non-protein coding RNAs (npcRNAs) in bacteria. Many of them are key players in the regulation of gene expression, taking part in various regulatory circuits, such as metabolic responses to different environmental stresses, virulence, antibiotic resistance, and host-pathogen interactions. This has contributed to the high adaptability of bacteria to changing or even hostile environments. Their mechanisms include the regulation of transcriptional termination, modulation of translation, and alteration of messenger RNA (mRNA) stability, as well as protein sequestration. Here, the mechanisms of gene expression by regulatory bacterial npcRNAs are comprehensively reviewed and supplemented with well-characterized examples. This class of molecules and their mechanisms of action might be useful targets for the development of novel antibiotics.
First record of the fungal genus Neodevriesia Quaedvl. & Crous (Ascomycota, Dothideomycetes, Neodevriesiaceae) isolated from scleractinian corals of Perhentian Islands, Malaysia

Lee LC, Rizman-Idid M, Alias SA, Palaniveloo K, Gu H

Biodivers Data J, 2022;10:e81533.
PMID: 36761577 DOI: 10.3897/BDJ.10.e81533

Fungal species members of the genus Neodevriesia have been known to occur in marine environments. This report documents the first record of the fungal genus Neodevriesia isolated from scleractinian corals. Three isolated strains were identified from a phylogenetic tree that was constructed, based on the nuclear ribosomal internal transcribed spacer and partial large subunit (ITS + LSU) DNA sequences. Isolates were closely related to both Neodevriesiashakazului (Crous) Crous and Neodevriesiaqueenslandica (Crous, R.G. Shivas & McTaggart) Crous, but formed a distinct clade with strong support that implies a potentially genetic variant of a known species or even a novel species. These findings contribute to the fungal diversity checklist in Malaysia and knowledge about marine fungi associated with scleractinian corals.
Responses of phytoplankton community to eutrophication in Semerak Lagoon (Malaysia)

Er HH, Lee LK, Lim ZF, Teng ST, Leaw CP, Lim PT

Environ Sci Pollut Res Int, 2018 Aug;25(23):22944-22962.
PMID: 29858995 DOI: 10.1007/s11356-018-2389-0

Effects of aquaculture activities on the environmental parameters and phytoplankton community structure were investigated in a semi-enclosed lagoon located at Semerak River, Malaysia. Elevated concentrations of phosphate and ammonia were observed at the aquaculture area and the inner lagoon. Relatively low dissolved oxygen, high total chlorophyll a, and high phytoplankton abundances but low species richness were recorded. Chaetoceros, Pseudo-nitzschia brasiliana, Blixaea quinquecornis, and Skeletonema blooms were observed, and some were associated with anoxia condition. Eutrophication level assessed by UNTRIX suggests that the water quality in the lagoon is deteriorating. Dissolved inorganic phosphorus and nitrogen at the impacted area were 15 and 12 times higher than the reference sites, respectively. Such trophic status indices could provide a useful guideline for optimal aquaculture management plan to reduce the environmental impact caused by aquaculture.
Fulltext Berberine-loaded liquid crystalline nanoparticles inhibit non-small cell lung cancer proliferation and migration in vitro

Paudel KR, Mehta M, Yin GHS, Yen LL, Malyla V, Patel VK, et al.

Environ Sci Pollut Res Int, 2022 Jul;29(31):46830-46847.
PMID: 35171422 DOI: 10.1007/s11356-022-19158-2

Non-small cell lung cancer (NSCLC) is reported to have a high incidence rate and is one of the most prevalent types of cancer contributing towards 85% of all incidences of lung cancer. Berberine is an isoquinoline alkaloid which offers a broad range of therapeutical and pharmacological actions against cancer. However, extremely low water solubility and poor oral bioavailability have largely restricted its therapeutic applications. To overcome these limitations, we formulated berberine-loaded liquid crystalline nanoparticles (LCNs) and investigated their in vitro antiproliferative and antimigratory activity in human lung epithelial cancer cell line (A549). 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), trypan blue staining, and colony forming assays were used to evaluate the anti-proliferative activity, while scratch wound healing assay and a modified Boyden chamber assay were carried out to determine the anti-migratory activity. We also investigated major proteins associated with lung cancer progression. The developed nanoparticles were found to have an average particle size of 181.3 nm with spherical shape, high entrapment efficiency (75.35%) and have shown sustained release behaviour. The most remarkable findings reported with berberine-loaded LCNs were significant suppression of proliferation, inhibition of colony formation, inhibition of invasion or migration via epithelial mesenchymal transition, and proliferation related proteins associated with cancer progression. Our findings suggest that anti-cancer compounds with the problem of poor solubility and bioavailability can be overcome by formulating them into nanotechnology-based delivery systems for better efficacy. Further in-depth investigations into anti-cancer mechanistic research will expand and strengthen the current findings of berberine-LCNs as a potential NSCLC treatment option.
Fulltext Non-protein coding RNA genes as the novel diagnostic markers for the discrimination of Salmonella species using PCR

Nithya R, Ahmed SA, Hoe CH, Gopinath SC, Citartan M, Chinni SV, et al.

PLoS One, 2015;10(3):e0118668.
PMID: 25774907 DOI: 10.1371/journal.pone.0118668

Salmonellosis, a communicable disease caused by members of the Salmonella species, transmitted to humans through contaminated food or water. It is of paramount importance, to generate accurate detection methods for discriminating the various Salmonella species that cause severe infection in humans, including S. Typhi and S. Paratyphi A. Here, we formulated a strategy of detection and differentiation of salmonellosis by a multiplex polymerase chain reaction assay using S. Typhi non-protein coding RNA (sRNA) genes. With the designed sequences that specifically detect sRNA genes from S. Typhi and S. Paratyphi A, a detection limit of up to 10 pg was achieved. Moreover, in a stool-seeding experiment with S. Typhi and S. Paratyphi A, we have attained a respective detection limit of 15 and 1.5 CFU/mL. The designed strategy using sRNA genes shown here is comparatively sensitive and specific, suitable for clinical diagnosis and disease surveillance, and sRNAs represent an excellent molecular target for infectious disease.
Fulltext Effects of substratum and depth on benthic harmful dinoflagellate assemblages

Lee LK, Lim ZF, Gu H, Chan LL, Litaker RW, Tester PA, et al.

Sci Rep, 2020 07 09;10(1):11251.
PMID: 32647125 DOI: 10.1038/s41598-020-68136-6

Microhabitats influence the distribution and abundance of benthic harmful dinoflagellate (BHAB) species. Currently, much of the information on the relationships between BHABs and microhabitat preferences is based on non-quantitative anecdotal observations, many of which are contradictory. The goal of this study was to better quantify BHAB and microhabitat relationships using a statistically rigorous approach. Between April 2016 to May 2017, a total of 243 artificial substrate samplers were deployed at five locations in the Perhentian Islands, Malaysia while simultaneous photo-quadrat surveys were performed to characterize the benthic substrates present at each sampling site. The screen samplers were retrieved 24 h later and the abundances of five BHAB genera, Gambierdiscus, Ostreopsis, Coolia, Amphidinium, and Prorocentrum were determined. Substrate data were then analyzed using a Bray-Curtis dissimilarity matrix to statistically identify distinct microhabitat types. Although BHABs were associated with a variety of biotic and abiotic substrates, the results of this study demonstrated differing degrees of microhabitat preference. Analysis of the survey results using canonical correspondence analysis explained 70.5% (horizontal first axis) and 21.6% (vertical second axis) of the constrained variation in the distribution of various genera among microhabitat types. Prorocentrum and Coolia appear to have the greatest range being broadly distributed among a wide variety of microhabitats. Amphidinium was always found in low abundances and was widely distributed among microhabitats dominated by hard coral, turf algae, sand and silt, and fleshy algae and reached the highest abundances there. Gambierdiscus and Ostreopsis had more restricted distributions. Gambierdiscus were found preferentially associated with turf algae, hard coral and, to a lesser extent, fleshy macroalgae microhabitats. Ostreopsis, almost always more abundant than Gambierdiscus, preferred the same microhabitats as Gambierdiscus and were found in microbial mats as well. With similar habitat preferences Ostreopsis may serve as an indicator organism for the presence of Gambierdiscus. This study provides insight into how BHAB-specific microhabitat preferences can affect toxicity risks.
RNomic identification and evaluation of npcTB_6715, a non-protein-coding RNA gene as a potential biomarker for the detection of Mycobacterium tuberculosis

Kanniappan P, Ahmed SA, Rajasekaram G, Marimuthu C, Ch'ng ES, Lee LP, et al.

J Cell Mol Med, 2017 10;21(10):2276-2283.
PMID: 28756649 DOI: 10.1111/jcmm.13148

Technological advances in RNA biology greatly improved transcriptome profiling during the last two decades. Besides the discovery of many small RNAs (sRNA) that are involved in the physiological and pathophysiological regulation of various cellular circuits, it becomes evident that the corresponding RNA genes might also serve as potential biomarkers to monitor the progression of disease and treatment. sRNA gene candidate npcTB_6715 was previously identified via experimental RNomic (unpublished data), and we report its application as potential biomarker for the detection of Mycobacterium tuberculosis (MTB) in patient samples. For proof of principle, we developed a multiplex PCR assay and report its validation with 500 clinical cultures, positive for Mycobacteria. The analysis revealed 98.9% sensitivity, 96.1% specificity, positive and negative predictive values of 98.6% and 96.8%, respectively. These results underscore the diagnostic value of the sRNA gene as diagnostic marker for the specific detection of MTB in clinical samples. Its successful application and the general ease of PCR-based detection compared to standard bacterial culture techniques might be the first step towards 'point-of-care' diagnostics of Mycobacteria. To the best of our knowledge, this is the first time for the design of diagnostic applications based on sRNA genes, in Mycobacteria.
Fulltext Aquella oligotrophica gen. nov. sp. nov.: A new member of the family Neisseriaceae isolated from laboratory tap water

Chan KG, See-Too WS, Chua KO, Peix Á, Goh KM, Hong KW, et al.

Microbiologyopen, 2019 Jul;8(7):e00793.
PMID: 30656855 DOI: 10.1002/mbo3.793

A bacterial strain designated as P08T was isolated from laboratory tap water during a water quality assessment in University of Malaya, Malaysia. The strain was a Gram-negative, rod-shaped, nonmotile, and aerobic bacterium. Complete genome of P08T comprised of a 2,820,660 bp chromosome with a G + C content of 36.43%. Both 16S rRNA phylogeny and phylogenetic tree inferred from the core gene matrix demonstrated that P08T formed a hitherto unknown subline within the family Neisseriaceae. Ortho average nucleotide identity (OrthoANI) values and the percentage of conserved proteins (POCP) calculated from complete genome sequence indicated low relatedness between P08T and its phylogenetic neighbors. Respiratory quinone analysis revealed Q-8 as the only detectable quinone. The predominant cellular fatty acids were identified as C14:0 , iso-C15:0 , and summed feature 3 (C16:1 ω7c/C16:1 ω6c). The polar lipids consisted of uncharacterized aminolipid, phosphatidylglycerol, and phosphatidylethanolamine. All aspects of phenotypic and phylogenetic data suggested that strain P08T represents a novel genus within family Neisseriaceae, for which the name Aquella gen. nov. is proposed. The type species of the genus is Aquella oligotrophica sp. nov., and the type strain is P08T (=LMG 29629T =DSM 100970T ).
Diverse harmful microalgal community assemblages in the Johor Strait and the environmental effects on its community dynamics

Hii KS, Mohd-Din M, Luo Z, Tan SN, Lim ZF, Lee LK, et al.

Harmful Algae, 2021 07;107:102077.
PMID: 34456026 DOI: 10.1016/j.hal.2021.102077

Coastal ecosystems are often subjected to anthropogenic disturbances that lead to water quality deterioration and an increase in harmful algal bloom (HAB) events. Using the next-generation molecular tool of 18S rDNA metabarcoding, we examined the community assemblages of HAB species in the Johor Strait, Malaysia between May 2018 and September 2019, covering 19 stations across the strait. The molecular operational taxonomic units (OTUs) of HAB taxa retrieved from the dataset (n = 194) revealed a much higher number of HAB taxa (26 OTUs) than before, with 12 taxa belong to new records in the strait. As revealed in the findings of this study, the diversity and community structure of HAB taxa varied significantly over time and space. The most common and abundant HAB taxa in the strait (frequency of occurrence >70%) comprised Heterosigma akashiwo, Fibrocapsa japonica, Pseudo-nitzschia pungens, Dinophysis spp., Gymnodinium catenatum, Alexandrium leei, and A. tamiyavanichii. Also, our results demonstrated that the HAB community assemblages in the strait were dependent on the interplay of environmental variables that influence by the monsoonal effects. Different HAB taxa, constitute various functional types, occupied and prevailed in different environmental niches across space and time, leading to diverse community assemblages and population density. This study adds to the current understandings of HAB dynamics and provides a robust overview of temporal-spatial changes in HAB community assemblages along the environmental gradients in a tropical eutrophic coastal ecosystem.
Habitat complexity affects benthic harmful dinoflagellate assemblages in the fringing reef of Rawa Island, Malaysia

Yong HL, Mustapa NI, Lee LK, Lim ZF, Tan TH, Usup G, et al.

Harmful Algae, 2018 09;78:56-68.
PMID: 30196925 DOI: 10.1016/j.hal.2018.07.009

Few studies have investigated the effect of fine-scale habitat differences on the dynamics of benthic harmful dinoflagellate assemblages. To determine how these microhabitat differences affect the distribution and abundance of the major benthic harmful dinoflagellate genera in a tropical coral reef ecosystem, a field study was undertaken between April-September 2015 and January 2016 on the shallow reef flat of the fringing reef of Rawa Island, Terengganu, Malaysia. Sampling of benthic dinoflagellates was carried out using an artificial substrate sampling method (fiberglass screens). Benthic microhabitats surrounding the sampling screens were characterized simultaneously from photographs of a 0.25-m2 quadrat based on categories of bottom substrate types. Five taxonomic groups of benthic dinoflagellates, Ostreopsis, Gambierdiscus, Prorocentrum, Amphidinium, and Coolia were identified, and cells were enumerated using a light microscope. The results showed Gambierdiscus was less abundant than other genera throughout the study period, with maximum abundance of 1.2 × 103 cells 100 cm-2. While most taxa were present on reefs with high coral cover, higher cell abundances were observed in reefs with high turf algal cover and coral rubble, with the exception of Ostreopsis, where the abundance reached a maximum of 3.4 × 104 cells 100 cm-2 in habitats with high coral cover. Microhabitat heterogeneity was identified as a key factor governing the benthic harmful dinoflagellate assemblages and may account for much of the observed variability in dominant taxa. This finding has significant implications for the role of variability in the benthic harmful algal bloom (BHAB) outbreaks and the potential in identifying BHAB-related toxin transfer pathways and the key vectors in the food webs.
Growth and epiphytic behavior of three Gambierdiscus species (Dinophyceae) associated with various macroalgal substrates

Mustapa NI, Yong HL, Lee LK, Lim ZF, Lim HC, Teng ST, et al.

Harmful Algae, 2019 Nov;89:101671.
PMID: 31672230 DOI: 10.1016/j.hal.2019.101671

Species of the benthic dinoflagellate Gambierdiscus produce polyether neurotoxins that caused ciguatera fish/shellfish poisoning in human. The toxins enter marine food webs by foraging of herbivores on the biotic substrates like macroalgae that host the toxic dinoflagellates. Interaction of Gambierdiscus and their macroalgal substrate hosts is believed to shape the tendency of substrate preferences and habitat specialization. This was supported by studies that manifested epiphytic preferences and behaviors in Gambierdiscus species toward different macroalgal hosts. To further examine the supposition, a laboratory-based experimental study was conducted to examine the growth, epiphytic behaviors and host preferences of three Gambierdiscus species towards four macroalgal hosts over a culture period of 40 days. The dinoflagellates Gambierdiscus balechii, G. caribaeus, and a new ribotype, herein designated as Gambierdiscus type 7 were initially identified based on the thecal morphology and molecular characterization. Our results showed that Gambierdiscus species tested in this study exhibited higher growth rates in the presence of macroalgal hosts. Growth responses and attachment behaviors, however, differed among different species and strains of Gambierdiscus over different macroalgal substrate hosts. Cells of Gambierdiscus mostly attached to substrate hosts at the beginning of the experiments but detached at the later time. Localized Gambierdiscus-host interactions, as demonstrated in this study, could help to better inform efforts of sampling and monitoring of this benthic toxic dinoflagellate.
Taxonomy and toxicity of Prorocentrum from Perhentian Islands (Malaysia), with a description of a non-toxigenic species Prorocentrum malayense sp. nov. (Dinophyceae)

Lim ZF, Luo Z, Lee LK, Hii KS, Teng ST, Chan LL, et al.

Harmful Algae, 2019 Mar;83:95-108.
PMID: 31097256 DOI: 10.1016/j.hal.2019.01.007

Thirteen isolates of Prorocentrum species were established from the coral reefs of Perhentian Islands Marine Park, Malaysia and underwent morphological observations and molecular characterization. Six species were found: P. caipirignum, P. concavum, P. cf. emarginatum, P. lima, P. mexicanum and a new morphotype, herein designated as P. malayense sp. nov. Prorocentrum malayense, a species closely related to P. leve, P. cf. foraminosum, P. sp. aff. foraminossum, and P. concavum (Clade A sensu Chomérat et al. 2018), is distinguished from its congeners as having larger thecal pore size and a more deeply excavated V-shaped periflagellar area. Platelet arrangement in the periflagellar area of P. malayense is unique, with the presence of platelet 1a and 1b, platelet 2 being the most anterior platelet, and a broad calabash-shaped platelet 3. The species exhibits consistent genetic sequence divergences for the nuclear-encoded large subunit ribosomal RNA gene (LSU rDNA) and the second internal transcribed spacer (ITS2). The phylogenetic inferences further confirmed that it represents an independent lineage, closely related to species in Clade A sensu Chomérat et al. Pairwise comparison of ITS2 transcripts with its closest relatives revealed the presence of compensatory base changes (CBCs). Toxicity analysis showed detectable levels of okadaic acid in P. lima (1.0-1.6 pg cell-1) and P. caipirignum (3.1 pg cell-1); this is the first report of toxigenic P. caipirignum in the Southeast Asian region. Other Prorocentrum species tested, including the new species, however, were below the detection limit.

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