Tropical life sciences research最新文献

Bactrocera dorsalis (Hendel) is a major quarantine pest species infesting most of the tropical fruits. Its infestation had significantly reduced and disrupted the export market trade, thus, very crucial to be controlled during the preharvest and postharvest. One of the most sustainable control methods is by using the radiation technique to reduce the pest population, thus curbing the spread of this pest to new geographical areas. The objective of this study was to measure the nucleotide changes in B. dorsalis (larval, pupal and adult stages) which had been irradiated with 50 to 400 Gray, using Gamma Cell Biobeam GM8000 irradiator with Cesium-137 source at the Malaysian Nuclear Agency, Selangor, Malaysia. Data from the treated samples (with and without morphological changes) were analysed using cytochrome oxidase subunit I (COI). The alignment of 59 sequences resulted in 0.92% variables with only four characters that were parsimony informative, and six sites (30, 60, 234, 282, 483 and 589) which had nucleotide changes, but had not been translated to another protein. Low polymorphism was presented on the sample groups, with only four haplotypes, but with high diversity value (Hd) = 0.5885. The phylogeny trees formed soft polytomy in both trees [neighbour joining (NJ) and maximum parsimony (MP)] presenting a mixture of individuals but did not show any significant difference between treatments. This finding concluded that low mutation had occurred on the treated B. dorsalis and this information is very valuable in getting new insight on the survival of B. dorsalis in the horticulture industry.

Neotropical cichlid possesses territorial aggression which explains their success as alien species that pose threats to local fauna. The feeding ecology of Midas cichlid, Amphilophus citrinellus species outside its native range had never been fully understood. We aim to determine the stomach content, length-weight relationship and condition factor of this non-native species in one of the agroecosystems in Malaysia. The fish was collected using a cast net, and the guts were dissected. The stomach content (n = 35) revealed Midas cichlids feed on a wide array of preys including fish, amphibian and gastropod. The b-value is 2.60 (negative allometric growth) and the relative condition factor, Kn is 1.04. This result represents an initial study on the feeding aspect of this cichlid. Subsequent and continued researches are needed to evaluate the feeding behaviour and prey preferences of this species in its introduced range.

Almost all research on natural attenuation and phytoremediation of sites contaminated with briny produced water has been conducted in temperate climates, however, there is a dearth of information on the use of tropical species for this purpose. It is within this context, that we investigated a spontaneously growing hypersaline spikerush from a contaminated site in southeast Mexico, to determine its soil salinity limits, the relationship between soil organic matter and salinity, and for preliminary documentation of floristic succession with Typha sp. for phytoremediation o f brine s pills. Soil was sampled (0 cm-20 cm) three times between 2018-2021, focusing on the end of the dry season (most critical period). The species tentatively identified as Eleocharis mutata was tolerant to soil hypersalinity (Electrical Conductivity: 125 dS/m) and appeared to generate a cyclic process of succession to recover areas with soil salinity levels higher than it could otherwise tolerate. A salinity gradient was found between the most heavily contaminated part of the site ("kill zone", > 212 dS/m), the first Eleocharis sp. individuals (125 dS/m), slowly advancing through the main spikerush stand, and finally into a cattail stand (< 8.02 dS/m). Similarly, an inverse relationship between Soil Organic Matter content and soil salinity was observed. This is the first time this species has been identified with a brine spill, its salinity limits determined, and investigated for use in phytoremediation of this kind.

This study aims to determine the biochemical compositions and the in vitro antitumour effect of the parotoid gland secretions (PGS) of the Egyptian toad (Bufo regularis). The total protein, lipid, carbohydrate contents, total antioxidant capacity (TAC), the median inhibitory concentration (IC₅₀) of 2,2-diphenyl-1-picrylhydrazyl (DPPH), sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) profile, amino acid analysis, gas chromatography-mass spectrometry (GC-MS) analysis and minerals were determined in PGS. The in vitro antitumour effect of PGS against human hepatocellular carcinoma (HepG-2), breast adenocarcinoma (MCF-7) and normal lung fibroblast (WI-38) cell lines were determined. The total protein, lipid and carbohydrate contents of PGS were 250 ± 15 mg/g D.W, 33 ± 3.2 mg/g D.W and 5 ± 0.65 mg/g D.W, respectively, while its TAC was 16.56 ± 0.12 mg/g D.W and the IC₅₀ of DPPH was 51.95 ± 2.95 mg/mL. Six protein bands varied between 10 and 50 kDa were found in PGS. Among amino acid profile, arginine showed the highest content in PGS. GC-MS analysis showed that 11-octadecenoic acid methyl ester was the highest concentrations in PGS. The half-maximal inhibitory concentrations (IC₅₀) of PGS against HepG-2, MCF-7 and WI-38 cells were 131.82 ± 6.14, 189.71 ± 8.95 and 685.65 ± 33.1 μg/mL, respectively. In vitro study showed that treatment of HepG-2 and MCF-7 cells with PGS increased the percentages of early and late apoptotic. While the percentages of early and late apoptotic WI-38 cells after treatment with PGS were 2.1% and 3.7%. Cell cycle analysis showed that PGS treatment arrested HepG-2 and WI-38 in S-phase, while arrested MCF-7 cells in G2/M phase. The present study concluded that PGS has a potent antioxidant activity with in vitro antitumour effect against HepG-2 and MCF-7 cells.

Changes in the existence of mangroves will have an impact on changes in food webs in their respective areas. The purpose of this study was to determine the food source of the macrozoobenthos community within the Lubuk Damar mangrove ecosystem. Stable isotopes, carbon and nitrogen were used to describe the food sources for macrozoobenthos in the mangrove ecosystem of the Lubuk Damar Ecosystem, Aceh Tamiang, Indonesia. The stable isotope analysis of ¹³C and ¹⁵N was carried out using Isotopic-Ratio Mass Spectrometry. Potential food sources at the study site based on stable isotope ratios ranged between -29.08‰ to -20.66‰ (δ¹³C) and 4.07‰ to 5.63‰ (δ¹⁵N); macrozoobenthos -25.00‰ to -14.76‰ (δ¹³C) and 5.59‰ to 7.73‰ (δ¹⁵N). The potential food sources tested at the study site consisted of seven sources, but not all food sources in the ecosystem were consumed by the invertebrate community. This study shows that mangrove leaf litter serves as a food source for some invertebrates, such as the bivalves, gastropods, polychaetes, sipunculans, brachiopods and crustaceans. The results of this study evidence that the examined mangrove ecosystem has a function as a provider of food sources in the surrounding waters, therefore its existence is very important supporting diversity of coastal waters.

The rapid emergence of multidrug-resistant (MDR) uropathogenic Escherichia coli (UPEC) strains pose a critical challenge in urinary tract infection (UTI) treatments. However, little work elucidated the resistance mechanisms of the MDR UPEC clinical strains in Malaysia. Therefore, this study aimed to determine the antimicrobial susceptibility profiles and the prevalence of antimicrobial resistance genes among the UPEC strains. Polymerase chain reactions were conducted to detect the presence of 6 antimicrobial resistance genes among 60 UPEC strains. Meanwhile, the antimicrobial resistance profiles against 9 antimicrobials were examined through the Kirby-Bauer disk diffusion method. In this study, the MDR isolates accounted for 40.0% (24/60), with the highest prevalence of resistance towards ampicillin (43/60; 71.7%), followed by tetracycline (31/60; 51.7%), nalidixic acid (30/60; 50.0%), co-trimoxazole (20/60, 33.3%), ciprofloxacin (19/60, 31.7%), levofloxacin (16/60, 21.6%) and chloramphenicol (10/60, 16.7%). In contrast, low resistance rates were observed among minocycline (1/60; 1.7%) and imipenem (0/60; 0.0%). bla _TEM was the most prevalent gene (36/60; 60.0%), followed by tetA (27/60; 45.0%), sul2 (25/60; 41.7%), sul1 (13/60; 21.7%) and tetB (8/60; 13.3%). Surprisingly, bla _SHV was not detected among the UPEC isolates. The MDR, ampicillin and tetracycline-resistant isolates were significantly associated with a higher prevalence of tetA, sul1, sul2 and bla _TEM. In contrast, tetB displayed no significant relationship with any of the antimicrobials tested. The patient's age and gender were not the risk factors for the carriage of the resistance genes. Our findings identified the common resistance genes carried by the antimicrobial resistant UPEC isolates and provide valuable insights into developing the best antibiotic prescription regime to treat UTIs in our local scene.

Mangrove ecosystems are crucial for protecting littoral regions, preserving biodiversity and sequestering carbon. The implementation of effective conservation and management strategies requires a comprehensive understanding of mangrove community structure, canopy coverage and overall health. This investigation focused on four small islands located within the Bunaken National Park in Indonesia: Bunaken, Manado Tua, Mantehage and Nain. Utilising the line transect quadrant method and hemispherical photography, the investigation comprised a total of 12 observation stations. Nain had the greatest average canopy coverage at 76.09%, followed by Mantehage, Manado Tua and Bunaken at 75.82%, 71.83% and 70.01%, respectively. Mantehage had the maximum species density, with 770.83 ind/ha, followed by Bunaken, Nain and Manado Tua with 675 ind/ha, 616.67 ind/ha and 483.34 ind/ha, respectively. The predominant sediment type observed was sandy mud and the mangrove species identified were Avicennia officinalis (AO), Bruguiera gymnorrhiza (BG), Rhizophora apiculata (RA), R. mucronata (RM), and Sonneratia alba (SA). On the small islands, S. alba emerged as the dominant mangrove species based on the importance value index (IVI). In addition, the Mangrove Health Index revealed that only 6.79% of the region exhibited poor health values, while 50% of the region was categorised as being in outstanding condition. These findings indicate that the overall condition of mangroves on these islands was relatively favourable.

The antimalarial properties of crude extracts from Quercus infectoria galls were investigated through bioassay-guided fractionation. Acetone (QIA) and methanol (QIM) crude extracts have been reported to have promising antimalarial activity against Plasmodium falciparum (3D7 strain). These extracts were subjected to fractionation using automated preparative high-performance liquid chromatography (prep-HPLC) to identify the most active fractions. Nine fractions were isolated from each extract, of which the fractions QIA11 and QIM16 showed antimalarial activity, with IC₅₀ values of 17.65 ± 1.82 μg/mL and 24.21 ± 1.88 μg/mL, respectively. In comparison, the standard antimalarial drug artemisinin has an IC₅₀ value of 0.004 ± 0.001 μg/mL). Through high-resolution liquid chromatography coupled with mass spectrometry (HR-LCMS) analysis of the fractions, four known compounds were successfully identified: gallic acid, ellagic acid, 1,3,6-tris-o-(3,4,5-trihydroxybenzoyl)-beta-d-glucose and 1-O,6-O-digalloyl-beta-D-glucose.

Theobroma cacao L. beans have long been used for food and medicinal purposes. However, up to 52%-76% of Theobroma cacao L. fruit comprises its husk, which are regarded as waste and oftentimes thrown away. In fact, cocoa pod husks actually possess a high antioxidant capacity. Antioxidants can be used to fight free radicals that are produced by environmental pollution. In order to simulate the effects of pollution, H²O² and cigarette smoke extract models were used respectively. However, the antioxidant properties are limited on the skin due to poor penetration. Hence, in order to increase the topical penetration, cocoa pod husk extract (CPHE) was also formulated into niosomes thereafter. CPHE was characterised using total phenolic content, total flavonoid content and three antioxidant assays. After that, cytotoxicity and cytoprotective assay were conducted on HaCaT cells, which represent the skin epidermis. CPHE was then formulated into niosomes subjected to stability and penetration studies for three months. CPHE was shown to contain 164.26 ± 1.067 mg GAE/g extract in total phenolic content and 10.72 ± 0.32 mg QCE/g extract in total flavonoid content. In addition, our results showed that CPHE possesses similar antioxidant capacity through 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, around eight-fold less through ABTS assay and approximately twelve-fold less through Ferric reducing power (FRAP) assay. The extract also showed comparable cytoprotective properties to that of standard (ascorbic acid). The niosome formulation was also able to increase the penetration compared to unencapsulated extract, as well as possess a good stability profile. This showed that CPHE, in fact, could be repurposed for other uses other than being thrown away as waste.

Adlay is an edible high nutritious minor cereal. The research aimed to study the adlay performance when cultivated intercropped on young teak (Tectona grandis L.f.) plantation. The treatments were consisted of two factors that were arranged by factorial (3 × 3) in randomised completed block design with four replicates. The first factor was three fertilisation dosages of NPK (16-16-16), as 0 g/hole (F0), 2 g/hole (F2) and 4 g/hole (F4). The second factors were three planting space as 2 m × 2 m (PS2), 3 m × 3 m (PS3) and 4 m × 4 m (PS4). The parameter observed were vegetative growth which was consisted of plant height, the number of leaves, tillers and sub tillers, leaf chlorophyll content, grain production and biomass weight. The results revealed that fertilisation treatment were significantly affected the growth and production of adlay. On 12 weeks after planting, the F4 treatment produced the tallest plant, and the highest leaf number. The highest grain number/plant was achieved on the F2 treatment that was significantly different compared with the control (F0). The shading intensity due to the teak coverage significantly affected adlay growth and production. The PS4 treatment produced the highest number of leaves, tillers and grains. The combination of F2 and PS4 treatments resulted in the best growth and production. The PS2 treatment which has lower light intercepted by plants due to lower incident light intensity, resulting in a significant reduction in plant growth and production. It is suggested that adlay offers potency as a component of agro-forestry on the teak plantations.