Locations In Thailand Research Articles

Identifying Suitable Genotypes for Different Cassava Production Environments—A Modeling Approach

Crop simulation models can be used to identify appropriate genotypes and growing environments for improving cassava yield. The aim of this study was to determine the best genotypes for different cassava production environments using the cropping system model (CSM)–MANIHOT–Cassava. Data from cassava experiments that were conducted from 2009–2011 and 2014–2015 at Khon Kaen, Thailand, were used to evaluate the model. Simulations were then conducted for different scenarios using four cassava genotypes (Kasetsart 50, Rayong 9, Rayong 11, and CMR38–125–77), twelve planting dates (at monthly intervals starting in January and ending in December), and ten locations in Thailand under fully irrigated and rainfed conditions using 30 years of historical weather data. Model evaluation with the experimental data for total biomass and storage root yield indicated that the model classified well for relative productivity among different planting dates. The model indicated that growing cassava under irrigated conditions generally produced higher biomass and storage root yield than under rainfed conditions. The cassava genotype CMR38–125–77 was identified for high biomass, while the genotype Rayong 9 was identified as a good genetic resource for high yield. The December planting date resulted in the highest biomass for all locations, while the February planting date produced the highest storage root yield for almost all locations. The results from this study suggest that the CSM–MANIHOT–Cassava model can assist in determining suitable genotypes for different cassava production environments for Thailand, and that this approach could be applicable to other cassava growing areas.

Detection and genetic characterization of "Candidatus Mycoplasma haemomacaque" infection among long-tailed macaques (Macaca fascicularis) in Thailand using broad-range nested polymerase chain reaction assay.

Background and Aim:Hemoplasmas are defined as small, epicellular parasitic bacteria that can infect the red blood cells of several mammalian species. Diseases caused by these bacteria range from asymptomatic infections to acute hemolytic anemia. However, data on hemoplasmas in non-human primates in Thailand remain to be limited. Therefore, this study aims to determine the occurrence and genetic diversity of hemoplasmas among long-tailed macaques in Thailand.Materials and Methods:Blood samples were collected from 339 long-tailed macaques in three provinces of Thailand. DNA was then extracted from the blood samples and tested for hemoplasma using broad-range nested polymerase chain reaction (PCR) based on the 16S rRNA gene. PCR-positive samples were sequenced, and phylogenetic analysis for species identification was conducted.Results:In total, 38 (11.2%) out of the 339 samples were found to be positive for hemoplasmas, based on the broad-range nested PCR assay of the 16S rRNA gene. The 16S rRNA sequences of Mycoplasma spp. were highly similar (98-99% identity) to “Candidatus Mycoplasma haemomacaque.” Furthermore, phylogenetic analysis using maximum likelihood demonstrated that the sequences were located in the same cluster of “Ca. M. haemomacaque.”Conclusion:The detection of hemoplasmas among long-tailed macaques in Thailand is reported. Genetic characterization confirmed that these hemoplasmas are closely related to “Ca. M. haemomacaque.” These results indicate that long-tailed macaques in several locations in Thailand may be infected and serve as reservoirs for this parasite.

Performance analysis of electricity generation from grid-connected photovoltaic system using All-Sky Index for Smart City projects in Thailand

Promotion of solar energy as a new promising renewable energy source for Smart City projects in Thailand plays an important role in driving the economy, society and the environment. A novel conceptual framework with different solar radiation indexes was developed to investigate and evaluate the efficiency of photovoltaic (PV) energy production by comparing predicted and actual results for energy acquired from the reference project. The trend of potential energy production was predicted from solar radiation data as the basis for further calculations to evaluate PV system efficiency through a techno-economic analysis of project development. A mathematical model was developed to predict the obtained electrical energy by considering the suitable location-specific solar radiation indexes including direct normal radiation, All-Sky insolation incident on a horizontal surface, direct normal irradiation and global horizontal irradiance. The developed model was tested with three existing Smart City projects at various locations in Thailand. The All-Sky index was determined as the most suitable option to evaluate new PV development projects. Highest energy production from the PV projects occurred in March and April. Energy production efficiencies of the PV systems were estimated in the range of 3.97–4.32 kWh/kWp. The techno-economic analysis suggested that the PV project had an internal rate of return of 14.30–15.75% and payback period of 6.18–6.74 years. The proposed conceptual framework was a promising tool for decision-making regarding Smart City PV projects.

Genetic characterization of coliform bacterial isolates from environmental water in Thailand

IntroductionIn contrast to the study in other part of the world, information about characteristics of plasmids carrying antimicrobial resistance genes (ARGs) in Enterobacteriaceae derived from environmental water in tropical Asian countries including Thailand is limited. This study, therefore, aimed to gain insight into genetic information of antimicrobial resistance in environmental water in Thailand. MethodsColiform bacteria were isolated from environmental water collected at 20 locations in Thailand and identified. Then, susceptibility profiles to ampicillin, cefazoline, cefotaxime, kanamycin, ciprofloxacin, sulfamethoxazole, tetracycline, and nalidixic acid were assessed. In addition, antimicrobial resistant genes integrons, and replicon types were analyzed. And furthermore, plasmids carrying blaTEM and tetM were identified by S1-PFGE analysis and confirmed transmissibility by transconjugation experiments. ResultsIn 130 coliform bacteria isolated, 89 were resistant to cefazoline while 41 isolates were susceptible. Cefazoline-resistant coliform bacteria were found to be significantly resistant to cefotaxime and tetracycline as compared to susceptible isolates. Hence, blaTEM and tetM correlating with β-lactam antibiotics and tetracycline, respectively, were analyzed found to co-localize on the IncFrepB plasmids in isolates from pig farms’ wastewater by S1-PFGE analysis. And furthermore, transmissibility of the plasmids was confirmed. ConclusionsResults obtained in this study suggested that ARGs in coliform bacteria may have been spreading on the farm via IncFrepB plasmids. Hence, appropriate use of antimicrobials and good hygiene management on the farm are required to prevent the emergence and spread of resistant bacteria.

Refugee and Asylum-Seeking Children in Mae Sot and Bangkok: An Analysis of Unmet Needs and Risks

Abstract This article reports on a longitudinal case study, which included site visits in Thailand from 2014 to 2015, and participant follow-up to mid-2018. It documents the lived experience of children from Syria, Sri Lanka, Pakistan, Vietnam, and Myanmar in two different locations in Thailand: Bangkok and Mae Sot (a district close to Thailand-Myanmar border with a long history of economic migrants and refugees from Myanmar). It documents perspectives of children and the adults in their lives while in exile. It presents an analysis of the children’s perspectives on needs and how unmet needs for safety, basic materials, health care, and education put them at risk of arrest, detention, abuse, and exploitation, and impact their psychological development. Contextual factors such as available services, existing policies and laws are also discussed in relation to the Convention on the Rights of the Child (CRC).

Malaria parasites in macaques in Thailand: stump-tailed macaques (Macaca arctoides) are new natural hosts for Plasmodium knowlesi, Plasmodium inui, Plasmodium coatneyi and Plasmodium fieldi

BackgroundCertain species of macaques are natural hosts of Plasmodium knowlesi and Plasmodium cynomolgi, which can both cause malaria in humans, and Plasmodium inui, which can be experimentally transmitted to humans. A significant number of zoonotic malaria cases have been reported in humans throughout Southeast Asia, including Thailand. There have been only two studies undertaken in Thailand to identify malaria parasites in non-human primates in 6 provinces. The objective of this study was to determine the prevalence of P. knowlesi, P. cynomolgi, P. inui, Plasmodium coatneyi and Plasmodium fieldi in non-human primates from 4 new locations in Thailand.MethodsA total of 93 blood samples from Macaca fascicularis, Macaca leonina and Macaca arctoides were collected from four locations in Thailand: 32 were captive M. fascicularis from Chachoengsao Province (CHA), 4 were wild M. fascicularis from Ranong Province (RAN), 32 were wild M. arctoides from Prachuap Kiri Khan Province (PRA), and 25 were wild M. leonina from Nakornratchasima Province (NAK). DNA was extracted from these samples and analysed by nested PCR assays to detect Plasmodium, and subsequently to detect P. knowlesi, P. coatneyi, P. cynomolgi, P. inui and P. fieldi.ResultsTwenty-seven of the 93 (29%) samples were Plasmodium-positive by nested PCR assays. Among wild macaques, all 4 M. fascicularis at RAN were infected with malaria parasites followed by 50% of 32 M. arctoides at PRA and 20% of 25 M. leonina at NAK. Only 2 (6.3%) of the 32 captive M. fascicularis at CHA were malaria-positive. All 5 species of Plasmodium were detected and 16 (59.3%) of the 27 macaques had single infections, 9 had double and 2 had triple infections. The composition of Plasmodium species in macaques at each sampling site was different. Macaca arctoides from PRA were infected with P. knowlesi, P. coatneyi, P. cynomolgi, P. inui and P. fieldi.ConclusionsThe prevalence and species of Plasmodium varied among the wild and captive macaques, and between macaques at 4 sampling sites in Thailand. Macaca arctoides is a new natural host for P. knowlesi, P. inui, P. coatneyi and P. fieldi.

Towards a Miniaturized Culture Screening for Cellulolytic Fungi and Their Agricultural Lignocellulosic Degradation.

The substantial use of fungal enzymes to degrade lignocellulosic plant biomass has widely been attributed to the extensive requirement of powerful enzyme-producing fungal strains. In this study, a two-step screening procedure for finding cellulolytic fungi, involving a miniaturized culture method with shake-flask fermentation, was proposed and demonstrated. We isolated 297 fungal strains from several cellulose-containing samples found in two different locations in Thailand. By using this screening strategy, we then selected 9 fungal strains based on their potential for cellulase production. Through sequence-based identification of these fungal isolates, 4 species in 4 genera were identified: Aspergillus terreus (3 strains: AG466, AG438 and AG499), Penicillium oxalicum (4 strains: AG452, AG496, AG498 and AG559), Talaromyces siamensis (1 strain: AG548) and Trichoderma afroharzianum (1 strain: AG500). After examining their lignocellulose degradation capacity, our data showed that P. oxalicum AG452 exhibited the highest glucose yield after saccharification of pretreated sugarcane trash, cassava pulp and coffee silverskin. In addition, Ta. siamensis AG548 produced the highest glucose yield after hydrolysis of pretreated sugarcane bagasse. Our study demonstrated that the proposed two-step screening strategy can be further applied for discovering potential cellulolytic fungi isolated from various environmental samples. Meanwhile, the fungal strains isolated in this study will prove useful in the bioconversion of agricultural lignocellulosic residues into valuable biotechnological products.

Quality Assessment and In Vitro Anti-diabetic Activity of Thunbergia laurifolia Stems and Leaves

The study aimed to evaluate pharmacognostic parameters for standardization of raw materials, Thunbergia laurifolia Lindl. (family: Thunbergiaceae) stems and leaves, as well as their active phytochemical (rosmarinic acid) contents. The antidiabetic potential was evaluated by yeast α-glucosidase inhibitory activity using p-nitrophenyl-α-D-glucopyranoside as substrate. Dried stems and leaves of Thunbergia laurifolia were collected from 15 different locations in Thailand. The microscopic anatomical and histological characteristics of stem and leaf were illustrated. The physico-chemical contents, including loss on drying, acid-insoluble ash, total ash, ethanol-soluble extractives, water-soluble extractives, and moisture of dried stems and leaves, were established. TLC-densitometry of rosmarinic acid in dried T. laurifolia stems and leaves were developed and revealed contents of 0.120 ± 0.079 and 0.291 ± 0.150 g per 100 g, respectively. Similarly, TLC-image analysis by ImageJ showed contents of 0.127 ± 0.094 and 0.303 ± 0.162 g per 100 g respectively (p > 0.05). Both quantitative TLC demonstrated their validity due to specificity, accuracy, repeatability, intermediate precision, limit of detection, limit of quantitation, and robustness. The antidiabetic potential of rosmarinic acid, T. laurifolia leaf and stem ethanolic extracts, and acarbose (positive control) exhibited IC50 of 0.31, 0.80, 5.89, and 1.48 mg/ml, respectively.

Mitochondrial ribosomal genes as novel genetic markers for discrimination of closely related species in the Angiostrongylus cantonensis lineage

The Angiostrongylus cantonensis lineage (Nematoda: Metastrongyloidea) consists of the closely related species A. cantonensis, Angiostrongylus malaysiensis, and Angiostrongylus mackerrasae. Various genetic markers have been used for species discrimination in molecular phylogenetic studies of this lineage. However, despite showing potential in other organisms, mitochondrial 12S and 16S ribosomal RNA (rRNA) genes have not been used for Angiostrongylus species discrimination. Therefore, this study assessed these genes’ suitability for inter- and intraspecies discrimination in the A. cantonensis lineage. The ultimate aim was to provide a novel genetic marker to support existing phylogenies. Sixty adult Angiostrongylus spp. worms from four geographic locations in Thailand were identified morphologically before molecular identification with 12S and 16S rRNA genes. Neighbor-joining and maximum likelihood algorithms were used for phylogenetic analyzes, and sequence variation was calculated to determine whether the genes could be used to discriminate among species. Furthermore, sequence variation was compared among previously used genetic markers to evaluate the robustness of the 12S and 16S rRNA genes as markers. Using both markers, the A. cantonensis lineage formed a monophyletic clade with a clear separation between A. cantonensis, A. malaysiensis, and A. mackerrasae. From our representative A. cantonensis and A. malaysiensis specimens, the genetic distance between the two clades was 6.8% –7.9% and 7.9% –10.0% for 12S and 16S rRNA genes, respectively, which is sufficient interspecific genetic variation for species discrimination. Higher levels of genetic variation were observed for the 16S rRNA gene, with 12 haplotypes and an intraspecific variation ≤2.2%. Thus, as a genetic marker, the 16S rRNA gene is comparable to mitochondrial protein-coding genes, which are commonly used in intra-level Angiostrongylus spp. studies. In conclusion, mitochondrial 12S and 16S rRNA genes can discriminate among closely related species in the A. cantonensis lineage, and they represent novel genetic markers for supporting existing phylogenies and verifying the phylogenetic position of A. mackerrasae.

16S rRNA Gene Amplicon Profiling of Baby and Adult Captive Elephants in Thailand.

Here, we present a 16S rRNA gene amplicon sequence data set and profiles demonstrating the bacterial diversity of baby and adult elephants from four different geographical locations in Thailand. The dominant phyla among baby and adult elephants were Bacteroidetes, Firmicutes, Proteobacteria, Kiritimatiellaeota, Euryarchaeota, and Tenericutes.

Comparative carbon footprint assessment of agricultural and tourist locations in Thailand

Many locations in the world have been changing their main economic activity from agriculture to tourism pursuing more favorable opportunities for their development. Such a change in economic structure also leads to a significant alteration in the provincial greenhouse gas emissions. In order to investigate these differences, this study compares the greenhouse gases emitted from the major human activities in agriculture and tourism-based provinces. For this purpose, Phuket and Phayao provinces in Thailand were chosen as representatives for tourism and agriculture, respectively. Environmental and economic performances of other tourist and agricultural areas in different countries were also presented to examine commonalities and differences. It was found that in the agricultural provinces, the major part of greenhouse gas emissions came from rice cultivation, while in the tourist provinces, from the energy sector. The comparative results among several locations show that the tourist areas (especially urban-tourism-based areas) mostly had a higher eco-efficiency due to the large income from tourism and other services. They also had higher greenhouse gas indices than agricultural areas, due to energy consumption. The performance of agriculture-and-tourism-based provinces was outstanding with the lowest average carbon footprint per capita while not performing badly on the other indices, partly due to a decrease in biomass burning. At a time when global warming is the major world problem, agri-tourism can be considered to be an optimal choice and direction for the sustainable development of both agricultural and tourist provinces.

A Study of Inspection for Electrical Safety Systems Case Study Four Locations in Thailand

This research presents study of inspection for electrical safety in electrical system. The four locations are observed. The objective of this research are to study the problems which may be occurred in electrical system and introduce the prevent ways. The four locations consist of 2 factories of paper and 2 animal food factories. For factory of paper, the total electrical load is 18,450 kVA which consists of 10 transformers and another 13,450 kVA which consists of 10 transformers. For the animal food 800 kVA, another is 1000 kVA which each location is a transformer. The inspected systems include transformer, main distribution board, ground and electrical wire systems. The check instruments are test oil maker, thermo scan, earth clamp tester, earth ground tester, infrared tester and outlet tester. The all data from test is analysed to compare among of four locations. For experimental results, it is of found that for transformer, the oil insulation transformer is lower than standard and silica gel is deteriorated and broken box, rubber shield and rubber gasket is broken and damage. For main distribution board, the ground value is lower than standard and the temperature of junction for breaker is high and more dust. For ground system, the ground value is lower than standard and broken. For wire system, the electrical is damaged because of heat and animal.

A validated HPTLC method for quantitative analysis of morin in Maclura cochinchinensis heartwood

ObjectiveThe study was conducted to develop and validate a high performance thin-layer chromatography (HPTLC)-densitometric method for the quantitative analysis of morin in Maclura cochinchinensis heartwood collected from different locations in Thailand. MethodsHPTLC analysis was performed on an aluminium sheet of silica gel 60 F254 using toluene: ethyl acetate: formic acid (36:12:7, volume percent) as a mobile phase. The densitometric scanning was performed at the wavelength 410 nm. HPTLC method was validated according to ICH guideline. ResultsThe proposed HPTLC method showed acceptable validation parameters. The content of morin in M. cochinchinensis heartwood collected from eight different provinces in Thailand were in the ranges of 1.53%−2.73%. ConclusionThe simple and sensitive HPTLC method was successfully developed and validated for determination of morin in M. cochinchinensis heartwood. The proposed HPTLC method was found to be simple, fast and inexpensive, and can be used for the routine quality control of raw materials.

85 Exploring the Feasibility of the Adapted Lifestyle - Integrated Functional Exercise (ALIFE) Programme to Prevent Falls among Older Adults in Thailand

Abstract Background Falls are the leading cause of injuries in older adults in Thailand. Exercise appears to be a strategy to reduce falls. There is a need to develop a fall prevention exercise programme to encourage participation and adherence. The adapted Lifestyle-integrated Functional Exercise (aLiFE) programme may be suitable by integrating exercise into daily routines as opposed to attending an exercise class. This study aimed to explore the acceptability and feasibility of the aLiFE programme in older Thai adults and identify if modifications are necessary for this population. Method To obtain older Thai adults' perspectives and stakeholders’ views, 40 community-dwelling older adults aged ≥ 60 years, in urban and rural locations in Thailand, and 14 stakeholders (e.g. healthcare professionals) working with older Thai adults were included. Qualitative methods were used to conduct focus groups and in-depth interviews with older adults, and semi-structured interviews with stakeholders. Thematic analyses using Framework Approach were conducted. Results Findings revealed positive views and identified four themes including: (a) individual factors, (b) perceptions of aLiFE, (c) recommendations for implementing aLiFE in Thailand, and (d) motivation. Older participants expressed interest in performing aLiFE in their daily activities, although some activities may need to be modified to fit the Thai cultural context. Stakeholders were concerned about how to motivate older Thai adults to adhere to aLiFE. Healthcare professionals and family members could play a major role to support older adults in uptake of aLiFE. Benefits (e.g. independence and fall prevention) may motivate older adults to engage in aLiFE. Clear and simple instructions were requested. Conclusion The aLiFE programme should be feasible and acceptable among older Thai adults. The aLiFE programme has been appropriately modified to be ‘Thai LiFE (TLiFE)’. A feasibility randomised controlled trial of the TLiFE programme has been conducted in older Thai adults.

Coinfection of tilapia lake virus and Aeromonas hydrophila synergistically increased mortality and worsened the disease severity in tilapia (Oreochromis spp.)

Global tilapia aquaculture has been experiencing serious disease problems for several years, and a breakthrough was made in 2014 when a novel virus called tilapia lake virus (TiLV) was linked to the observed high mortalities in tilapia. Notably, previous studies from Thailand, Egypt, and Malaysia identified TiLV along with various well-known pathogenic bacterial species. In this study, we have further investigated the significance of TiLV-bacterial concurrent infections in farmed tilapia. First, field studies across different locations in Thailand were performed to assess the extent of TiLV-bacterial coinfections in natural farm-raised tilapia. From a total of 52 cases, 15% were attributed to a single TiLV infection, 14% were positive for either Streptococcus species (spp.) or Aeromonas spp. without TiLV, and in 31% of the fish, TiLV was found coinfecting with bacterial species, the majority of which was credited to a TiLV-Aeromonas spp. coinfection. To further examine the impact of a TiLV-Aeromonas spp. coinfection on the severity of disease in tilapia, we co-challenged tilapia with TiLV, Aeromonas hydrophila, and combinations thereof under laboratory conditions. We found that the coinfection between TiLV and 107 colony forming units (CFU)/fish of A. hydrophila resulted in 93% cumulative mortality compared to 0%, 34%, and 6.7% in the control, single TiLV and single A. hydrophila infection, respectively. Serious histopathological findings were found in the dual challenged fish, presenting syncytial hepatitis and severe loss of hepatic sinusoid and glycogen storage, as well as red blood cell depletion and vaculaotion of lymphotyces in the spleen. Analysis of the bacterial load recovered from the fish revealed a high level of bacteria from the co-challenged fish compared to those only challenged with A. hydrophila. Collectively, our results show that TiLV is commonly found concurrently with well-known pathogenic bacteria such as Aeromonas spp. and that such infectious agents seem to synergistically exacerbate the disease severity in tilapia. This is an important finding because it has significant implications for implementing the most effective disease management strategies. Future work trying to decipher the details of the interaction between TiLV, bacteria and the tilapiine immune system will be crucial to better understand disease progression and pathogenesis.

Effect of zinc-biofortified seeds on grain yield of wheat, rice, and common bean grown in six countries.

Seeds enriched with zinc (Zn) are ususally associated with better germination, more vigorous seedlings and higher yields. However, agronomic benefits of high-Zn seeds were not studied under diverse agro-climatic field conditions. This study investigated effects of low-Zn and high- Zn seeds (biofortified by foliar Zn fertilization of maternal plants under field conditions) of wheat (Tritcum aestivum L.), rice (Oryza sativa L.), and common bean (Phaseolus vulgaris L.) on seedling density, grain yield and grain Zn concentration in 31 field locations over two years in six countries. Experimental treatments were: (1) low-Zn seeds and no soil Zn fertilization (control treatment), (2) low-Zn seeds + soil Zn fertilization, and (3) Zn-biofortified seeds and no soil Zn fertilization. The wheat experiments were established in China, India, Pakistan, and Zambia, the rice experiments in China, India and Thailand, and the common bean experiment in Brazil. When compared to the control treatment, soil Zn fertilization increased wheat grain yield in all six locations in India, two locations in Pakistan and one location in China. Zinc-biofortified seeds also increased wheat grain yield in all four locations in Pakistan and four locations in India compared to the control treatment. Across all countries over 2 years, Zn-biofortified wheat seeds increased plant population by 26.8% and grain yield by 5.37%. In rice, soil Zn fertilization increased paddy yield in all four locations in India and one location in Thailand. Across all countries, paddy yield increase was 8.2% by soil Zn fertilization and 5.3% by Zn-biofortified seeds when compared to the control treatment. In common bean, soil Zn application as well as Znbiofortified seed increased grain yield in one location in Brazil. Effects of soil Zn fertilization and high-Zn seed on grain Zn density were generally low. This study, at 31 field locations in six countries over two years, revealed that the seeds biofortfied with Zn enhanced crop productivity at many locations with different soil and environmental conditions. As high-Zn grains are a by-product of Zn biofortification, use of Zn-enriched grains as seed in the next cropping season can contribute to enhance crop productivity in a cost-effective manner.

Chemovariation and antibacterial activity of extracts and isolated compounds from species of Ixora and Greenea (Ixoroideae, Rubiaceae).

BackgroundA large number of secondary metabolites can be obtained from plants used for traditional medicine in two related genera (Ixora and Greenea) in the subfamily Ixoroideae (Rubiaceae), but there are only a few detailed studies on their bioactivities. Therefore, the main goals of this study were to determine the antibacterial activities of lipophilic extracts from plants of some Ixora and Greenea species native to Thailand, and to isolate some pure compounds from those extracts. Moreover, we compared the occurrence of compounds in different plant parts of samples from different habitats to better understand their variation.MethodsA total of 56 lipophilic extracts were obtained from the leaves, stem bark, and root bark of eight Ixora and two Greenea species collected at various locations in Thailand. Isolated compounds were identified using nuclear magnetic resonance. Antimicrobial activities were evaluated against four Gram-positive and nine Gram-negative human pathogenic bacterial strains.ResultsExtracts from I. javanica, I. nigricans, I. brunonis, and G. montana, along with isolated scopoletin, exhibited antibacterial activities against Gram-positive methicillin-resistant Staphylococcus aureus ATCC 43300, with minimum inhibitory concentration values ranging from 64 to 256 µg/mL. The occurrence of scopoletin, isofraxidin, and geniposidic acid in lipophilic extracts showed some variation among different plant parts and species.ConclusionsLipophilic extracts of Ixora and Greenea species have the potential to be developed as anti-Gram-positive agents, in particular to counter infections of methicillin-resistant S. aureus strains. The chemical profiles showed differences between floristic regions but similarity within the same plant parts.

Rapid detection of tilapia lake virus using a one-step reverse transcription loop-mediated isothermal amplification assay

Tilapia lake virus (TiLV) is a newly emerging viral disease in tilapia with recent outbreaks in many parts of the world. There is an urgent need to develop an accurate, sensitive, on-farm method for rapid detection of TiLV to limit economic loss and prevent the spread of the virus into new geographical areas. In this study, we developed a rapid, one-step reverse transcription, loop-mediated, isothermal amplification (RT-LAMP) method for the detection of TiLV in fish tissues. Our results revealed that the RT-LAMP assay was able to detect TiLV infection in infected cell culture materials, and fish samples collected from different geographic locations in Thailand. In total, 166 tissue samples were collected from TiLV-infected fish and uninfected fish from tilapia farms in Thailand with a history of TiLV outbreaks, and fish showing clinical signs of TiLV infection were tested using our RT-LAMP protocol. The RT-LAMP assay offered high specificity and sensitivity compared to reverse transcription polymerase chain reaction (RT-qPCR) assay. These results supported the application of the RT-LAMP assay for the diagnosis of TiLV with benefits including reduced analysis time and easy interpretation of results based on the colorimetric change, thus offering a diagnostic tool in resource-limited countries where there is an urgent need for rapid diagnostic assay to guide TiLV control.

Correlation between genotypes and geographic distribution of Entamoeba nuttalli isolates from wild long-tailed macaques in Central Thailand

Entamoeba nuttalli found in non-human primates is the phylogenetically closest species to Entamoeba histolytica and is potentially pathogenic. However, infection of wild long-tailed macaques (Macaca fascicularis) with E. nuttalli has not been found. In this study, the prevalence of Entamoeba infections in wild long-tailed macaques was examined in seven locations in six provinces of Thailand. The positive rate for E. nuttalli in 214 fecal samples was 43.9% using PCR, but no infection with E. histolytica or Entamoeba dispar was found, demonstrating that long-tailed macaque is one of the natural hosts for E. nuttalli. Twenty-four E. nuttalli isolates were successfully cultured and four of them were axenized. The sequences of the 18S ribosomal RNA genes of E. nuttalli from long-tailed macaques differed from those of E. nuttalli isolates from other species of wild macaques. Eleven types of sequences in serine-rich protein genes were identified in the 24 isolates and these were specific for each location in Thailand. By analysis of six tRNA-linked short tandem repeat loci, these isolates were divided into 14 types, and each type was also location-specific. Phylogenetic analysis revealed correlation between genotypes of the parasite and the geographic distribution of the host macaques. Genetic distance and geographic distance correlated significantly in a Mantel test, with r values of 0.888 based on the tRNA-linked short tandem repeat loci and 0.815 based on the serine-rich protein genes. These results suggest that genetic divergence and co-evolution of the parasite occurred during dispersion and colonization of the host macaque, and that genotypic analysis of the parasite may enable identification of the geographic localization of the host.

Genetic variation of Aedes aegypti mosquitoes across Thailand based on nuclear DNA sequences

The Aedes aegypti L. mosquito is the primary vector of dengue viruses in Thailand, where dengue disease is a major public health problem in both urban and rural areas. Understanding the genetic variation of Ae. aegypti populations can help to understand the distribution, population structure and gene flow of this species. Single nucleotide polymorphism (SNP) markers were used to analyze the genetic variation of 21 Ae. aegypti populations collected across six geographic locations in Thailand. Nuclear DNA sequences of four putative neutral fragments located on different chromosomes were examined. An average of 14 SNPs per kb was detected per population. Tajima's D statistical test showed no significant deviation from the neutral equilibrium model in the majority of populations, suggesting that the detected patterns of variation were under random mutation and genetic drift equilibrium. Relatively low genetic differentiation was detected between all mosquito populations.