Tropical life sciences research最新文献

Equine strongyles are harmful gastrointestinal parasites affecting horses' health and productivity. In tropical regions, environmental conditions, including temperature and soil type, significantly influence the development and survivability of strongyle larvae. This study aims to assess the development and survival of third-stage larvae (L3) of strongyles under different temperatures and soil types commonly found in Malaysia. Faecal samples from five adult horses aged between 22-24 years that were kept under a semi-intensive management system and had no history of recent anthelmintic treatment for the past six months and did faecal culture at various controlled temperatures: 21 ± 1°C, 26 ± 1°C, 29 ± 1°C and 32 ± 1°C, and soil type (peat, clay, residual and sandy). The presence of strongyle eggs was identified using faecal floatation, while larval development was monitored daily for 30 consecutive days using the Baermann technique and light microscopy. The time required for development from egg to L3 was shortest at 29°C-32°C (5-6 days) and longest at 21°C-26°C (8-9 days). Peat soil supported the highest survivability (up to 68%) compared to sandy and clay soils, which had the lowest survivability (50% and 41%, respectively). This study highlights the role of tropical soil environments in larval survival. It offers insights into improved parasite control strategies, suggesting future investigations using field trials to explore the role of faecal moisture and microbial interactions in L3 persistence.

Human activities, particularly agriculture and urbanisation often have detrimental effects on aquatic ecosystems and their ecosystem services to varying degrees. Organic pollutants (e.g., pesticides, pharmaceuticals, Per- and Polyfluoroalkyl Substances [PFAS]) and abiotic stressors (e.g., salinity, temperature, pH) are common stressors of freshwater habitats with expanding platforms documenting these problems or issues. This research addresses the effects of individual and combined methomyl (insecticide) and elevated salinity on movement, hydration and egestion of the snail Physa venustula. Snails were exposed to treatment concentrations of 100 μg/L of methomyl and 5 g/L salinity for 96 h. Results indicated a significant reduction in snail movement when exposed to salinity (74%), and in combination with methomyl (67%). In contrast, we did not observe significant effects on egestion or hydration across treatments. These findings suggest that there is an energy trade-off to maintain homeostasis from the other physiological processes. Reduced movement can alter feeding rates, predator avoidance behaviour leading to changes in ecosystem structure and function. This research can provide critical insight into how short-term exposure to multiple stressors affects freshwater invertebrates and suggest P. venustula may be useful for early detection of water quality changes, especially in regions where chemical monitoring is limited.

An extreme climatic change due to anthropogenic activities causes disruptions in ecosystems and threatens the planet's overall balance. Hydroponic is smart and sustainable agriculture practice that aims to produce two times more yield than traditional practices. To investigate the efficiency of hydroponics technique, the morpho-physiological responses of selected vegetable species were analysed. Tomato (Solanum lycopersicum L.), Eggplant (Solanum melongena), Lettuce (Lactuca sativa), Green Chili (Capsicum annuum) and Okra (Abelmoschus esculentus) were selected for the experiment. Soil nutrients analysis and hydroponics nutrients uptake analysis were also carried out side by side using UV-Visible Spectroscopy, Atomic Absorption Spectroscopy and Titration method. In hydroponic water analysis, it was found that 42% of supplied Cl- had been taken up by the plants whereas 79% of all supplied Zinc and Iron had been taken up by the plants. The uptake percentages of other anions and cations ranged between 45% to 62%. Morpho-physiological responses of Lettuce and Tomato in soil-based and hydroponic experiments were almost similar. Whereas, hydroponically grown Okra, Green Chili and Eggplant showed maximum height, roots length, number of leaves and weight. Overall findings showed that hydroponic system was more efficient in terms of crops yield, water usage and environmental contamination. Thus, it is recommended to increase the duration of experiment in future to further verify the climatic change effects.

German cockroaches (Blattella germanica L.) are major residential pests, with reports of insecticide resistance emerging from numerous regions worldwide. This study aims to investigate the global distribution of insecticide resistance in German cockroaches, explore the underlying resistance mechanisms, identify the specific insecticides that have shown reduced efficacy and examine how resistance has developed globally. A literature review was conducted, collecting relevant publications from journal databases such as Google Scholar, Science Direct, Wiley Online Library and Oxford Academic Journal up to the year 2024. The keywords used in the search included "resistance," "insecticide," "Blattella germanica" and "German cockroach." The review included studies that provided data from field strains using contact-based assays. In total, 102 studies on resistance spanning 23 countries across four continents were identified. Resistance has been reported against 60 different insecticidal active ingredients, primarily from the pyrethroid and organophosphate classes, with varying degrees of resistance noted. Very high levels of resistance (RR > 100) were mostly recorded for pyrethroids. The predominant resistance mechanism observed involved metabolic mechanisms, particularly the increased activity of cytochrome P450 enzymes, followed by esterases and glutathione S-transferases (GST). Target-site mechanisms were also reported, including knockdown resistance (kdr) (L993F) and resistance to dieldrin (Rdl) (A302S). The combined mechanisms of resistance result in broad-spectrum resistance and potential cross-resistance. This review highlights the critical need for ongoing surveillance of insecticide resistance in German cockroaches and emphasises the urgency of developing more effective pest management strategies to address the escalating challenge of resistance.

This research investigated the impact of cyanide and crude protein content in host plants on feed consumption, survival rate, yield and residual cyanide content in eri silkworms. The study utilised castor leaves from a native variety and cassava leaves from five varieties-Rayong 11, Rayong 72, Huai Bong 60, Kasetsart 50 and CMR43-08-89-which exhibited varying cyanide contents (53.66 mg/kg to 365.22 mg/kg fresh weight) and crude protein contents (17.52% to 26.04% dry matter). Eri silkworms were reared under controlled laboratory conditions (25ºC-32ºC and 65-75 %R.H.) using a Completely Randomized Design (CRD). The survival rate of eri silkworms ranged from 80.00% to 94.66% and did not differ significantly (p > 0.05) among the different host plant treatments. However, castor leaves were the most consumed (20.8756 g/larva), resulting in higher cocoon weight (2.5990 g), pupa weight (2.2842 g) and fecundity (435.63 eggs/female moth) compared to cassava leaves (p ≤ 0.05). Eri silkworms reared on Rayong 72 leaves had the lowest cocoon weight, pupa weight, shell weight and fecundity. Cyanide content analysis in eri silkworms at the late fifth instar larvae stage showed no significant difference (5.71 mg/kg to 6.33 mg/kg fresh weight, p > 0.05). However, the highest cyanide content was observed in pupae fed Rayong 72 leaves (14.92 mg/kg fresh weight), which significantly differed from other host plants (p ≤ 0.05). In summary, cyanide and crude protein content in host plant leaves influenced the feed consumption, yield and cyanide residue in eri silkworms.

Silver nanoparticles (AgNPs) have been widely applied as antimicrobial materials. In this work, a new fabrication method of AgNPs has been proposed through a combination of tea seed saponin extraction as a non-ionic biological surfactant and cetyltrimethylammonium chloride (CTAC) as a co-surfactant. The morphology and optical properties of as-prepared AgNPs were analysed by SEM and UV-vis absorbance measurement, respectively. The results indicate that AgNPs obtained high homogeneous particle sizes with a mean diameter of 44.5 ± 3.8 nm. The optical property of AgNPs was exhibited through a UV-vis absorbance spectrum of ~420 nm. In addition, the antibacterial behaviour of E. coli (ATCC 25922) was increased according to the AgNPs concentration. The diameter of inhibition zones was 12 mm, 14 mm and 16 mm under AgNPs concentrations of 0.8 ppm, 8 ppm and 80 ppm, respectively. Our initial trial treatment of AgNPs in young broccoli (Brassica oleracea) exhibited promising potential for plant protection in agricultural applications.

This study establishes a foundational understanding of the dietary preferences of two insectivorous bats (Family Hipposideridae), Hipposideros larvatus and Hipposideros cineraceus caught in the rice field areas. The investigation focused on the analysis of their fecal pellets collected in areas near Gunung Keriang, Kota Setar, Kedah. A total of 40 pellets from eight individuals were meticulously examined. These eight bats were categorised into two distinct groups based on sex and reproductive stages (lactating and non-reproductive) from the two bat species. The dietary composition of H. larvatus comprised 55.2% Coleoptera, 23.2% Lepidoptera, 10.1% Hemiptera, 9.2% Diptera and 2.1% Hymenoptera. The diet of the bat species was significantly dominated by Coleoptera, accounting for over half of the overall dietary percentage. On the contrary, H. cineraceus, exhibited a different diet composition, with 68.0% Lepidoptera, 18.5% Coleoptera, 7.0% Diptera, 5.1% Hemiptera and 0.6% Hymenoptera. These variations in dietary preferences can be attributed to factors such as their differing abilities to digest chitin found on the elytra (forewing) of beetles, variations in size between the two species, distinct echolocation frequencies and differing reproductive states. Both H. larvatus and H. cineraceus have the potential to serve as effective pest controllers in rice fields by reducing insect pest populations, especially from the order Lepidoptera (rice stem borer) and Hemiptera (leafhoppers). Further research should be conducted in different locations to gain a more comprehensive understanding of these bat species' diets and whether they exhibit exclusive or generalised feeding patterns.

Indian mackerel (Rastrelliger spp.) is a species with high catch volumes, amounting to approximately 451.750 tonnes over five years. This substantial yield holds significant potential for local communities, making sustainable utilisation crucial. This study focuses on the fishing season of Indian mackerel (Rastrelliger spp.) and the development of a habitat suitability model in the waters of the western of Banda Sea, Indonesia. The Fishing Season Index (FSI) method identified November as the peak fishing season, with the highest CPUE recorded at 220 kg trip^-1. During this period, stable salinity levels were observed, which supported the reproductive processes of Indian mackerel. Additionally, high rainfall and strong winds facilitated local upwelling, influencing currents and bringing nutrients to the surface, which were consumed by mackerel larvae. The ANN (Artificial Neural Network) models used to estimate potential fishing zones for Indian mackerel demonstrated high accuracy, with an error rate of just 1.12%. The analysis revealed that salinity and currents were the most influential environmental parameters, contributing 16% and 14% to catch success during the peak fishing season with salinity levels at 34.2 psu and current velocity at 3.29 cm s^-1. The implementation of this model in analysing Indian mackerel habitats and their relationship with environmental factors supports data and technology-driven fisheries management. This study also introduces a novel integration of the Fishing Season Index (FSI) method and ANN modelling to simultaneously identify peak fishing seasons and predict potential fishing zones based on dynamic oceanographic parameters. The application of machine learning in this model enables the identification of non-linear relationships between environmental variables and fish distribution with high accuracy, representing a significant advancement in predictive habitat modelling for Indian mackerel in Indonesian waters. This approach contributes to sustainable fisheries resource management and aligns with the achievement of SDG 14 in Indonesia.

Physalis minima L. is an herbaceous plant with ethnobotanic importance across many Asian cultures. In this study, we sequenced and assembled the plastid genome (plastome) of a P. minima sample from Malaysia, and conducted intraspecific pairwise and phylogenetic analyses with available data of its relatives. Our sample had a plastome of 156,973 bp in size with a GC content of 37.5%. The genome was circular, consisting of a large single-copy of 87,196 bp, a small single-copy of 18,447 bp and a pair of inverted repeats of 25,665 bp each. A total of 129 genes were annotated, including 84 CDSs, 37 tRNAs and eight rRNAs. Between the China and Malaysia accession, 458 variable sites were identified, and the pairwise distance was 0.003. Phylogenetic analysis was conducted using the complete plastome sequence based on the maximum likelihood and Bayesian inference methods. The findings revealed that our sample was significantly differentiated from the accession from China, and that both P. minima accessions clustered away from P. angulata, the synonym suggested by certain taxonomic authorities. This study facilitates precise taxonomic identification of P. minima within ethnomedicinal frameworks, enabling its distinction from closely related or putatively synonymous species that may exhibit divergent phytochemical compositions. These results provide important insights into the genetic diversity and taxonomic status of P. minima, and support its informed use in future research, conservation, and medicinal applications.

This study evaluated the performance of mixed sex postlarval (PL) populations of giant freshwater prawn, Macrobrachium rosenbergii, cultured under Integrated Periphyton Technology (IPT) and Recirculating Aquaculture System (RAS) conditions. The trials were conducted in triplicate over 44 days of nursery culture (T1), followed by 60 days of growth after size separation (T2 and T3). The carbon-to-nitrogen (C:N) ratios were optimised through molasses supplementation. The water quality parameters in both systems remained within acceptable ranges. Key performance indicators, including body weight, survival rate, average daily gain, specific growth rate, harvest biomass and feed conversion ratio (FCR), were analysed across T1 and T2. While nursery performance (T1) was not significantly different between the IPT and RAS systems, Morphological distinctions among male morphotypes (BC, OC and SM) and females were characterised, with sex-specific growth performance compared across T1 and T2, as were size-separated populations in T3. IPT demonstrated more effective production of Blue Claw (BC) prawns during the grow-out phase (T2). IPT, a zero-discharge system, matched or outperformed RAS, while eliminating the need for external effluent management, while equivalent FCR did not establish periphyton as a supplemental food source within the production volume. Although size separation yielded variable benefits, enhancement of overall productivity was inconclusive. This study highlights IPT as a sustainable alternative to conventional RAS, offering equivalent FCR, and lower energy consumption, and land resource requirement. Further investigations are warranted to optimise intensive IPT systems for economic feasibility and environmental sustainability, contributing to broader advancements in aquaculture.