Science Letters

Spatial Variability of Alkalinity in the Waters Surrounding the Dangli Island Group of Langkawi, Malaysia

2025-06-04T05:18:45+08:00

This paper presents a comprehensive assessment of the spatial distribution of alkalinity in the waters surrounding the Dangli Island group of Langkawi during the southwest monsoon. Sampling was conducted at 12 strategically positioned stations around the island, capturing data at three distinct depths—upper, middle, and bottom. The determination of Total Alkalinity (TA) was performed using an Auto-titrator, with synthetic seawater employed as a reference. Alkalinity, indicative of water's capacity to neutralize acids, plays a pivotal role in influencing pH stability. The average alkalinity values for each station revealed notable variations, with Station 11 (ST11) exhibiting the highest (2201.12 µEq/kg) for the surface water, (2260.45 µEq/kg) for the middle water and (2113.7 µEq/kg) for the bottom., while ST5 recorded the lowest among the stations. Analysis of the data indicates a slight elevation in alkalinity levels at the middle (2141.10 µEq/kg) compared to the upper (1982.07 µEq/kg) and bottom depths (2038.50 µEq/kg). Two-way ANOVA results demonstrated a significant difference between sampling stations (p-value = 0.016, p < 0.05), suggesting spatial heterogeneity. Conversely, no significant differences were observed between depth levels (p > 0.05). The study also explores the intricate relationship between salinity and alkalinity, emphasizing the nuanced dynamics of this association in the context of ocean acidification. Notably, a correlation coefficient (r) of -0.06 was obtained, indicating a very weak or negligible inverse relationship between salinity and alkalinity. This observation underscores the complexity of the interplay between these variables, influenced by factors such as biological activity, carbonate system dynamics, and human activities. The findings contribute valuable insights into the spatial distribution and factors influencing alkalinity in the marine environment surrounding the Dangli Island group, offering a foundation for future research and environmental management strategies.

Assessment of Heavy Metals Contamination in Estuaries Area of Sungai Kilim, Pulau Langkawi

2025-06-04T05:28:29+08:00

Heavy metal pollution poses a critical environmental challenge, particularly in estuarine ecosystems such as the Kilim River in Langkawi, Malaysia. This study investigates the distribution of heavy metals (Co, Cr, Fe, Pb, and Zn) in sediment samples collected from 16 locations in Sungai Kilim using the aqua regia closed digestion method. Sediments were processed to prevent contamination, including soaking in 5% nitric acid, drying, pulverizing, and sieving before analysis. Inductively coupled plasma optical emission spectrometry (ICP-OES) was employed for precise analysis, with accuracy validated through reference material testing. The concentrations of heavy metals varied, with Co ranging from 4.50 to 68.49 ppm, Cr from 12.55 to 184.26 ppm, Fe from 0.83% to 4.48%, Pb from 3.42 to 76.55 ppm, and Zn from 11.90 to 75.20 ppm. Enrichment factor calculations showed no significant enrichment for Co (2.354), Cr (2.019), and Zn (1.532), but Pb displayed a moderately severe enrichment (6.198), indicating significant contamination. The findings highlight notable heavy metal concentrations in Sungai Kilim sediments, particularly for lead, suggesting environmental risks exacerbated by industrial and urban activities. These results emphasize the need for targeted environmental management strategies to mitigate contamination and safeguard the ecological health of the estuarine ecosystem.

Fish Biodiversity At Pulau Tuba and Kilim Geopark, Langkawi, Malaysia

2025-06-04T07:40:42+08:00

The continuous development of tourism, fishing and other activities in Langkawi, Malaysia have increasingly pressured the island’s marine ecosystem. Monitoring the impacts is crucial for ensuring the sustainable development of the area. Fish population dynamics are widely used as an ecological indicator for assessing pollution levels and overall health of aquatic ecosystems. The objective of this research is to assess the biodiversity (richness and evenness) of fish species at Pulau Tuba and Kilim GeoPark as to evaluate the impacts of surrounding activities. This research was conducted at two locations within the waters surrounding Pulau Langkawi: Pulau Tuba and Kilim GeoPark, which were selected due to their similar coastal topology and characteristics but varying level of anthropogenic activities. The fish sampling was carried out three times at three different points in each study area. The data were analyzed using Shannon-Wiener and Simpson’s diversity indices to determine the significant differences in fish species diversity between the two locations. Fish biodiversity index at Pulau Tuba was recorded at 1.52 while Kilim GeoPark was 1.32. The results indicated that the biodiversity of fishes found at Pulau Tuba is higher although it is not significantly different than at Kilim GeoPark. These suggest that anthropogenic activities may have given an impact toward the biodiversity of fish, but more data is needed to confirm the hypothesis. A continuous and more rigorous monitoring is suggested to have a more comprehensive input for policy design. The impact of surrounding activities may take some time to affect the fish dynamics, thus more direct impact such as water quality shall be recommending for future studies.

Impedance Data Interpretation for a Modified LSCF via Distribution of Relaxation Times Analyses

2025-06-04T07:49:09+08:00

Lanthanum Strontium Cobalt Ferrite Oxide (LSCF) is a cathode material for intermediate-temperature solid oxide fuel cells operating from 500 to 800 °C. To enhance the cathode's performance, it is essential to comprehend the electrochemical behavior, which is frequently analyzed using complex nonlinear least-squares (CNLS) analysis. Nevertheless, this analysis demonstrates certain constraints in the detailed interpretation of the electrochemical processes, particularly at the electrode-electrolyte interface. The distribution of relaxation times (DRT) is supportive when deconvoluting complex impedance spectra and has gained increased attention. Hence, this study is conducted to measure the electrochemical impedance data analyses by CNLS and the DRT of a fabricated modified 25 mm symmetrical cell, m-LSCF|BCZY|m-LSCF (m=modified, LSCF = La0.6Sr0.4Co0.2Fe0.8O3 and BCZY = BaCe0.54Zr0.36Y0.1O2.95). In a Nyquist plot, the cell shows depressed semi-circles, representing a few interface processes occur. The DRT analysis reveals the semi-circles consisting of four different sub-processes (represented by four peaks) than CNLS (represented by four impedance arcs). The results show that the area-specific resistance (ASR) values for CNLS were 0.3 Ωcm2 and 0.75 Ωcm2, with 0.25 Ωcm2 and 0.71 Ωcm2 for DRT analysis.

Bioprospection of Indigenous Molds Obtained from Diospyros javanica Leaves as Agents of Plastic Biodegradation

2025-06-04T07:56:33+08:00

Plastic is a material that is difficult to decompose because it has long polymer chains, high molecular weight, and hydrophobic properties. Plastic degradation is often carried out chemically, but this results in various environmental problems such as the release of toxic by-products and pollutants. The environmentally friendly solution to reduce plastic is by natural decomposition with the help of microorganisms which is known as biodegradation. This research provides an appropriate solution to the problem of plastic degradation by utilizing indigenous mold obtained from the Diospyros javanica tree. Biodegradation tests were carried out to determine the ability of plastic degradation by these indigenous molds which are assumed to be efficient in an environmentally-friendly plastic degradation. Indigenous molds were identified and assumed to be three types of mold isolates of the genera Humicola, species Aspergillus flavus, and Aspergillus niger. Biodegradation analysis was carried out using Fourier Transform Infrared (FTIR) analysis in order to detect changes in functional groups (chemical compounds and bonds) and Scanning Electron Microscope (SEM) analysis to help visualize the plastic surface of the test results. The results show that the genera Humicola, Aspergillus flavus, and Aspergillus niger have potential for plastic biodegradation. The DJ1 isolate (Humicola genus) had the largest percentage of plastic degradation efficiency, namely 23.96 % after 15 days of incubation. The results within this research suggests that Humicola shows a great potential to fill in a role in plastic biodegradation.

Proteomic Approaches to Unravel Complex Interactions Between Ganoderma boninense and Oil Palm in Basal Stem Rot Disease: A Scoping Review

2025-06-04T08:01:35+08:00

Ganoderma boninense poses the biggest threat to the oil palm industry by inducing basal stem rot (BSR) in Malaysia, a leading palm oil-producing nation. Protein analysis is one of the potential methods in early detection of infected plants by understanding the changes in protein molecules which are useful as biomarkers. However, proteomic methods are not widely used due to their complex protein analysis in nature and the diversity of protein characteristics, including variations in abundance, structure, and post-translational modifications. Thus, a scoping review was analysed based on related literatures by identifying gaps and limitations in protein analysis for managing G. boninense. This scoping review was conducted following PRISMA guidelines. The results were searched using different databases: Scopus, Asean Citation Index (ACI), ScienceDirect, PubMed, and Web of Science (WoS). The keywords used were "Ganoderma boninense" OR "basal stem rot" AND "proteomics" OR "protein analysis" OR "proteomic profiling" OR "mass spectrometry" OR "protein expression." 116 articles were collected from the various databases, and only 13 significant articles were included after reviewing the abstracts and removing the duplicates. The relevant articles showed that proteomic methods, particularly LC-MS, 2-DE, and MALDI TOF/TOF were effectively used to study the molecular reactions of oil palms to G. boninense infection. There was still a lack of proteomic data with other research on certain protein classes, and other post-translationally modified proteins which may contribute to an incomplete understanding of G. boninense pathogenicity. It is recommended that these gaps be addressed by employing advanced proteomic approaches in future studies to facilitate a deeper comprehension of complex protein interactions. The analysis of proteomic methods employed for studying G. boninense is essential for the oil palm sector, as this strategy can contribute to valuable insights that can advance strategies for early detection of the pathogen infection.

Influence of Wettability Characteristic on Biofouling Resistance of Polytetrafluoroethylene (PTFE) and Polyvinylidene Fluoride (PVDF) Film Embedded on Glass Fiber

2025-06-06T14:41:53+08:00

Biofouling is a persistent issue for marine structures, reducing operational efficiency and increasing maintenance costs. Antifouling coatings prevent the accumulation of fouling organisms by forming physical barriers that inhibit the attachment of microorganisms, contaminants, and particles. However, conventional coatings often face limitations such as environmental degradation, frequent reapplication, and limited durability. This study examines the role of surface wettability in biofouling resistance by comparing polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF) films embedded with glass fiber (GF) to uncoated GF as a reference system, focusing on the influence of hydrophobic and hydrophilic properties. Contact angle measurements revealed distinct wettability characteristics: PTFE/GF exhibited high hydrophobicity (125.95°), while PVDF/GF (59.4°) and GF (63.1°) were hydrophilic. After 120 days of seawater exposure, PTFE/GF displayed the lowest biofouling growth (35.6%), significantly outperforming PVDF/GF (89.6%) and GF (94.7%). PTFE/GF also demonstrated self-cleaning capabilities, with fouling levels decreasing from 57.8% at 60 days to 35.6% at 120 days, emphasizing its durability and efficiency in harsh marine environments. The superior antifouling performance of PTFE/GF is attributed to its hydrophobicity, low surface energy, and the "lotus effect," which repels water and prevents microbial adhesion by allowing water droplets to bead and roll off, carrying away debris. In contrast, the hydrophilic PVDF/GF promotes water spreading, encouraging microbial attachment and biofilm formation, resulting in greater fouling growth. This study highlights the critical role of hydrophobicity in antifouling coatings, demonstrating that materials like PTFE significantly enhance biofouling resistance. These findings provide a foundation for developing durable, efficient antifouling solutions tailored to the challenging conditions of marine environments.

Antioxidant, Anti-Tyrosinase, and Anti-Collagenase Properties of Elephantopus scaber Leaf and Root Extracts

2025-06-06T14:45:28+08:00

Excessive exposure to ultraviolet (UV) radiation is the most common cause of accelerated skin aging. Due to the geographical location, skin aging has become a growing health concern in Malaysia, leading to the ever-increasing demand for skincare products. However, some skin care products contain hazardous chemicals such as paraben and formaldehyde. Thus, consumers are now switching to natural-based skincare products. Elephantopus scaber (E. scaber), also known as "Tutup Bumi", is one of the medicinal herbs found in Malaysia. Although E. scaber is widely used for medicinal purposes, its anti-skin aging properties remain unknown. This study aimed to investigate the antioxidant and anti-skin aging potential of E. scaber leaf and root extracts. Total phenolic content (TPC), total flavonoid content (TFC), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays were performed to determine the antioxidant properties of E. scaber extracts. The extracts were assayed for tyrosinase and collagenase inhibition to determine their anti-skin aging properties. The root extract of E. scaber (ESR) showed higher TPC (63.34 ± 0.56 mg GAE/g) and TFC (156.46 ± 7.43 mg QE/g) compared to E. scaber leaf (ESL) extract. However, the ESL showed a better DPPH radical scavenging activity. The ESR also showed higher inhibitory activities against tyrosinase and collagenase. Therefore, E. scaber, especially the root part, is a promising natural candidate for anti-skin aging treatment.

Antioxidant and anti-acetylcholinesterase activities of selected plants from Asteraceae family related to Alzheimer’s disease: A review

2025-06-06T14:50:00+08:00

Alzheimer’s disease (AD) is often associated with deficit levels of neurotransmitters acetylcholine (ACh) due to hydrolysis by acetylcholinesterase (AChE). Oxidative damage is also found to contribute to AD. Since neurons are vulnerable to high amounts of reactive oxygen species (ROS), damaged neurons lead to declined cognitive and learning abilities. In addition, the current medications for AD pose worrying side effects to AD patients. Hence, more efforts have been made to discover the potential of plants in providing safer alternatives for AD treatment since they are rich with bioactive compounds like phenolics and flavonoids. The scope of this review is narrowed to Asteraceae family plants: Achillea filipendulina, Achillea millefolium, Artemisia herba-alba, Calendula officinalis, Enhydra fluctuans and Hertia cheirifolia. In the present study, the relationship between total phenolic content (TPC), total flavonoid content (TFC) and antioxidant property have been investigated in these plants subjected to different extraction techniques, plant parts, solvent polarity, type of extracts and plant harvesting period. Effects of these factors in anti-AChE activity were also discussed. Besides that, the possible synergistic effects between antioxidant and anti-AChE in the plants have been identified. The summarised results have proven that different extraction parameters bring about different bioactivity intensities. Next, results showed a strong, positive relationship between TPC, TFC and antioxidant activity except for C. officinalis where its root methanolic extract demonstrated an opposite trend. Furthermore, possible dual effects in plants were detected in four out of five plants reviewed except for A. herba-alba methanolic extract whereby the plant exhibited greater antioxidant properties while its essential oil demonstrated stronger anti-AChE properties. This study emphasized the paramount importance of considering all factors that influence the composition of bioactive compounds and their desired biological activities. Moreover, our findings on the knowledge of possible dual effects in selected plants could advance the development of therapeutic drugs in AD treatment.

Unmasking Microplastic Pollution: A Study on the Distribution and Impact of Microplastics in Yuehai Lake, China

2025-06-06T14:56:52+08:00

The increasing use of plastics has led to a significant environmental challenge: microplastic (MP) pollution, which poses threats to aquatic ecosystems and human well-being. Freshwater habitats, including lakes, are particularly vulnerable to such contamination. This study investigates the characteristics and distribution of microplastics (MPs) in Yuehai Lake, China. Water samples were collected from five locations and analyzed using laser direct infrared (LDIR) spectroscopy to assess MP presence and concentration. MPs were detected at all sampling sites. The highest concentration, exceeding 1400 particles/L, was recorded at S5 (Lijing Street), while S1 (Yuehai Fishing Base), a site primarily used for fishing activities, recorded a concentration of 1100 particles/L. MP fragments were the predominant form (63.36%), followed by fibers (33.22%) and films (3.42%). Seventeen polymer types were identified, with fluororubber (FKM) being the most common (22.80%), followed by fluorosilicone rubber (FVMQ, 16.90%), chlorinated polyethylene (CPE, 13.58%), and polyvinyl chloride (PVC, 10.10%). The composition and morphology of MPs suggest automobile tire contamination as a primary source. Over 90% of the MPs detected were small-sized particles (20–100 μm). The Pollution Load Index (PLI) confirmed MP contamination at all sites. These findings provide essential insights to support governmental initiatives in environmental protection, policy development, and public awareness, contributing to improved ecological health and sustainability.

The Potential of Local Microalgae Isolates in Biotechnological Applications

2025-06-06T15:05:13+08:00

Microalgae biofilms have emerged as a promising candidate in biotechnology, including enhancing biomass production for various applications and as an efficient alternative to conventional wastewater treatment. This study explores the potential of local microalgae in reducing pollutants in wastewater by sequestering nitrogen and phosphorus while generating biomass that can be used for human food and animal feed. Local microalgal isolates are known to have potential in offering cost-effective, efficient, and sustainable nutrient removal while enabling resource recovery and minimizing ecological risks in wastewater treatment. A total of eight microalgal biofilm samples were successfully isolated and preliminary identified. Three were from the Chlorophyta group, one was Cyanobacteria while the other belonged to the Ochrophyta group. Highest biomass yield was produced by isolate MA12 at a 90.0% increase in wet weight mg/L, followed by 76.9% and 70.0% by MA22 and MA19, respectively. When grown in synthetic wastewater for seven days, the highest reduction in TN was observed in MA18 at 43.5% while MA7 showed a remarkable performance of 95.0% of reduction of TP. Integrating microalgae biofilms into wastewater treatment systems can thus enhance pollutant removal and contribute to the circular economy by converting waste into valuable bioproducts. This study highlights the novelty of using local microalgae isolates both in environmental protection and resource recovery, paving the way for their implementation in sustainable wastewater management practices.

Determination of Macronutrients and Trace Elements in Potential Nickel Hyperaccumulators from Ultramafic Areas in Sabah using Atomic Spectroscopic Analysis

2025-06-06T15:11:01+08:00

Hyperaccumulators species are widely distributed on ultramafic lands where it is capable to accumulate extremely high concentration of metalloids such as Ni, Co and Mn in the above-ground parts without showing any signs of toxicity. However, related information on identified hyperaccumulators from Sabah such as elemental distribution is insufficient due to lack of fundamental studies. The aim of this study is to contemplate hypernickelophores as tropical metal crop candidate for sustainable metal farming and environmental cleanup through evaluation of macronutrients and trace elements such as Na, Ca, K, Ni, Co and Mn in identified hyperaccumulators using Atomic Absorption Spectrophotometer (AAS). 8 species of previously identified hyperaccumulating plants (Psychotria sarmentosa, Glochidion sp. ‘bambangan’, Rinorea, bengalensis, Rinorea javanica, Actephila alenbakeri, Walsura pinnata, Xylosma luzonensis and Mischocarpus sundaicus were collected from serpentinite area in Kinabalu Park for this study. 4 hypernickelophores which are G. sp. ‘bambangan’, R. bengalensis, R. javanica and P. sarmentosa were found with the accumulation of Ni as much as 10 784 mg/kg, 13 196 mg/kg, 13 780 mg/kg and 17 085 mg/kg, respectively. These findings suggest that these species hold promise for phytoremediation and phytoextraction in Malaysia, particularly in regions with ultramafic soils. Therefore, further study on G. sp. ‘bambangan’ should be carried out as it is an undescribed taxon which is endemic to Sabah. Apart from that, it is crucial to determine the most suitable agronomic practices for the hypernickelophore so the metal bioavailabilty can be increased. Therefore, it can be utilized in the application of metal farming which is a novel mineral extraction technology.

Mass-Spectrometry Phytochemical Profiling of Etlingera coccinea (Blume) S. Sakai & Nagam from Sabah

2025-06-06T15:21:48+08:00

Etlingera coccinea (Blume) S. Sakai & Nagam is classified in the genus of the Etlingera (Zingiberaceae). Locally known as ‘tuhau’ in Sabah, it is used as traditional remedy such as to cure food poisoning, stomachache as well as condiment in cooking. Previous studies on the genus Etlingera have focused on its phytochemical compounds and biological activities. However, mass-spectrometric profiling of crude extracts has not been reported. In this research, E. coccinea stalks were taken from two different localities: Ranau and Tambunan areas to determine their chemical profiles. Each of locations have three types of crude fractions: n-hexane, chloroform and methanol. The phytochemical screening for both locations show the presence of flavonoids, terpenoids and tannins. Through thorough chemical profiling, the library of Liquid Chromatography Mass-Spectrometry (LC-MS) analysis results showing 10 and 8 known metabolites found in Ranau methanolic, and chloroform extracts respectively. While for Tambunan methanolic and extracts were 8 and 4 known metabolites found. Additionally, Gas Chromatography Mass-Spectrometry (GC-MS) analysis identified of n-hexane extracts from Ranau and Tambunan reported 15 and 9 known metabolites respectively. All identified phytochemical compounds have their own potential application such as antibacterial, anti-fungal, antioxidants, anti-inflammatory, and anti-cancer. The roles could serve as a basis for further exploration of the chemical composition as well as the biological activities of E. coccinea.

Antibiofilm and antibacterial properties of Streptococcus and Staphylococcus from the oral microbiome

2025-06-06T15:26:11+08:00

The human oral microbiome plays an important role in balancing beneficial and harmful microorganisms in the oral cavity. Certain oral bacteria are known to produce substances that inhibit the formation of microbial biofilm and growth of potentially pathogenic microorganisms. The oral microbiome of the Malaysian population is largely uncharacterized, and there is very little information on its diversity and potential as a source of probiotics or antibiofilm and antibacterial metabolites. The objectives of this study are to characterize the taxonomic composition of the oral microbiome in selected healthy Malaysian subjects; and to assess the capacity of bacterial isolates from oral microbiome to produce antibiofilm and antibacterial compounds. Metagenomic sequencing showed that the oral microbiome includes predominantly bacteria from the phyla Firmicutes, Bacteroidetes, Proteobacteria, Fusobacteria and Actinobacteria while Streptococcus, Haemophilus, Neisseria, Phorphyromonas and Fusobacterium are the most represented genera Altogether, 117 bacterial cultures were successfully isolated from these microbiomes, where 14 (12.0%) isolates inhibited Staphylococcus epidermidis (ATCC 35984) biofilm formation at maturation stage with highest activity observed at 94.8%. Twelve (10.3%) isolates displayed antibacterial activity with the highest activity observed against Streptococcus mutans (ATCC 25175) at 76.9%, followed by Bacillus subtilis (ATCC6633) at 56.6%; but no activities were observed against E. coli (ATCC 25922) or S. aureus (ATCC 25923). Identification via 16S rRNA sequencing showed that the majority of the oral bacterial isolates displaying the antibiofilm and/or antibacterial activities were Streptococcus salivarius followed by strains of S. aureus. Two of these isolates, SA78 and SA10, produced both antibiofilm and antibacterial activities and were identified to be S. salivarus suggesting the potential of this species in treating oral infections and improving dental health. Understanding the oral microbiome composition and using resident beneficial bacterial species as oral probiotics may provide a novel strategy for addressing oral diseases.