Subtropical Asia Research Articles

Habu vipers (Protobothrops flavoviridis) are an overlooked but important reservoir of the zoonotic tick Amblyomma testudinarium (Acari: Ixodidae) in subtropical Asia

Habu vipers (Protobothrops flavoviridis) are an overlooked but important reservoir of the zoonotic tick Amblyomma testudinarium (Acari: Ixodidae) in subtropical Asia

Environmental salinity differentiates responses to acute hypothermal stress in milkfish

Global warming has led to an increase in the frequency of cold extremes, causing significant economic losses in aquaculture, particularly in subtropical regions. Milkfish (Chanos chanos) holds significant importance in aquaculture within subtropical Asian regions. Despite milkfish's ability to tolerate varying salinity levels, frequent cold snaps associated with extreme weather events have caused substantial mortality. Understanding the molecular and cellular mechanisms underlying cold stress-induced cell death is crucial for developing effective strategies to mitigate such losses. Given the pivotal role of the liver in fish physiology, we established a primary milkfish hepatocyte culture demonstrating robust proliferation and expressing a unique marker leptin A. The molecular characterization of cold-treated hepatocytes at 18 °C showed that the mRNA levels of superoxide dismutase (sod1) and catalase (cat), responsible for neutralizing reactive oxygen species (ROS), were downregulated in freshwater (FW) conditions, while cat expression was upregulated in seawater (SW) conditions. This differential modulation of ROS signaling implies distinct responses in FW and SW, leading to higher ROS levels and increased cell death in FW condition compared to those in SW. Transcriptomic analysis of liver tissues from milkfish reared in FW or SW, with or without cold stress, revealed distinct gene expression patterns. Although cold stress affected a common set of genes in both FW and SW conditions, SW-specific cold responsive genes are associated with metabolic pathways while FW-specific genes were linked to cell proliferation pathways. Notably, gene set enrichment analysis highlighted the downregulation of cytochrome-related genes, a major source of ROS production, in response to cold stress in SW. In summary, our study unveils an insightful mechanism whereby the salinity of SW counteracts cold stress-induced ROS signaling, emphasizing the feasibility and practicality of preconditioning fish in SW as a preventive measure against cold stress-induced mortality.

An Insight into Ethanopharmacology, Phytochemistry, and Pharmacological Properties of Genus Andrographis

Abstract: Andrographis is a member of the family Acantheceae. It contains approximately 44 accepted species. Among them, Andrographis paniculata has been extensively studied during the last decade. The genus contains triterpenoids as the main class of compound, along with carotenoids, flavonoids, glycosides, xanthones, phenolic compounds, and fatty acid compounds. A. paniculata has been reported in Ayurveda, homeopathy, naturopathy, and Siddha. Traditionally, the genus is utilized in treating diarrhea, parasitic problems, liver illness, various skin problems, fever, snake bites, cough and many more. Pharmacological activities like antioxidant, neuroprotective, anti-inflammatory, antimalarial, hepatoprotective, antibacterial antiviral, anticancer, and antidiabetic have been documented in it with scientific evidence. Various components found in this genus show broad biological opportunities for novel medicinal medicines. Andrographolide is the major chemical constituent present in almost all the species. It has been reported for various pharmacological activities, mostly for antioxidant and anticancer. The genus is widely spread among India, China, Southeast Asia, Sri Lanka, Vietnam, Thailand, and basically tropical and subtropical Asia. In India, it is found in Nallamala Hills, Andhra Pradesh, and South India. The present review has provided a critically analyzed vision of phytochemistry, traditional uses, and pharmacological applications of the genus Andrographis. The current information was collected systematically from scientific databases, including Google Scholar, Pub Med, ACS Publications, SciFinder, Science Direct, and Web of Science.

Synchronous spring precipitation in Southeastern China and Bengal: a potential indicator for the Indian summer monsoon?

Abstract Spring precipitation in southeastern China and Bengal, occurring during the transitional phase from winter to summer monsoons, serves as a critical window into the dynamics of large-scale circulations and the subsequent summer monsoon. While many studies have analyzed spring precipitation in southeastern China and Bengal, their interconnections and implications for the summer monsoon have remained relatively under explored. We utilized the Empirical Orthogonal Function of spring precipitation to reveal Synchronous Spring Precipitation (SSP) in southeastern China and Bengal. This synchronicity is bridged by the East Asian Subtropical Jet (EASJ) that extends from Bengal to southeastern China. The EASJ was predominantly correlated with precipitation in southeastern China prior to the 1990s, while it developed a more profound connection with precipitation in Bengal after the 1990s. Notably, SSP anomalies occurred during the developing phase of the El Niño-Southern Oscillation (ENSO). The predictive capacity of SSP for the Indian summer monsoon (ISM) amplifies during periods of the intensified SSP-ENSO correlations and positive phase of the North Pacific Meridional Mode. Tree-ring based reconstructions spanning the past two centuries further corroborate the persistent linkages among the SSP, ISM, and ENSO. Our research sheds light on the intricate interplay of these factors and their significance in understanding and predicting the monsoon dynamics in the region.

Plastome Evolution, Phylogenomics, and DNA Barcoding Investigation of Gastrochilus (Aeridinae, Orchidaceae), with a Focus on the Systematic Position of Haraella retrocalla.

Gastrochilus is an orchid genus containing about 70 species in tropical and subtropical Asia with high morphological diversity. The phylogenetic relationships among this genus have not been fully resolved, and the plastome evolution has not been investigated either. In this study, five plastomes of Gastrochilus were newly reported, and sixteen plastomes of Gastrochilus were used to conduct comparative and phylogenetic analyses. Our results showed that the Gastrochilus plastomes ranged from 146,183 to 148,666 bp, with a GC content of 36.7-36.9%. There were 120 genes annotated, consisting of 74 protein-coding genes, 38 tRNA genes, and 8 rRNA genes. No contraction and expansion of IR borders, gene rearrangements, or inversions were detected. Additionally, the repeat sequences and codon usage bias of Gastrochilus plastomes were highly conserved. Twenty hypervariable regions were selected as potential DNA barcodes. The phylogenetic relationships within Gastrochilus were well resolved based on the whole plastome, especially among main clades. Furthermore, both molecular and morphological data strongly supported Haraella retrocalla as a member of Gastrochilus (G. retrocallus).

Ants (Hymenoptera: Formicidae) intercepted at South Korean points of entry

AbstractSixty‐two species of ants (Hymenoptera: Formicidae) were intercepted at South Korean points of entry on plants for planting imported from tropical and subtropical Asia from 1996 to 2023. Information on the number of interceptions, host plants, consignment origin and their years of interception is provided. Data on intercepted ant species were analysed to determine potential invasive species of ants that could cause damage not only to agricultural, forestry, and natural ecosystems but also to industry and that could endanger human health.

Molecular phylogeny of Trictenotomidae (Coleoptera: Tenebrionoidea): insights into species validation and biogeography of genus Autocrates

Abstract Trictenotomidae, one of the most charismatic and enigmatic groups of beetles, known for their large size and distinctive mandibles, is widely distributed throughout tropical and subtropical Asia. New species are continually being discovered, and the known range of the group has been expanded considerably by the discovery of Autocrates maqueti Drumont in the Korean Peninsula, ~2,000 km from its previously known distribution in the Chinese mainland highlands. A comprehensively sampled multigene phylogenetic tree of Trictenotomidae, including all six species of Autocrates and five species of Trictenotoma, was reconstructed using multigene data. Using the resulting phylogeny, we performed divergence time estimation, biogeographical assessments, and molecular species delimitation. All six known species of the genus Autocrates were found to be valid in all four molecular species delimitation scenarios, indicating the need for further taxonomic research on these poorly understood taxa. The A. maqueti population in South Korea forms a genetically distinct clade in all genetic analyses, suggesting that it is a natural distribution rather than a result of anthropogenically driven spread. The Korean A. maqueti population is likely to have been isolated since ~1.8 Mya, when the Yellow Sea was still a landmass, highlighting the need for targeted conservation measures in South Korea.

Annotated catalogue of Pakistani Acrididae (Orthoptera: Caelifera: Acridoidea)

An annotated catalogue of Acrididae (Orthoptera: Caelifera) of Pakistan and its two adjacent territories is presented. A total of 169 species (including subspecies) belonged to 66 genera and 29 tribes with 14 subfamilies are reported from this region. Oedipodinae (56) was the most species-rich subfamily, followed by Gomphocerinae (30), Acridinae (15), Calliptaminae with (12), Eyprepocnemidinae (12) Oxyinae (9), Hemiacridinae (10), Cyrtacanthacridinae (8), Catantopinae (7), Tropidopolinae and Teratodinae each with (3), Spathosterninae (2) and Coptacrinae, and Melanoplinae are represented by a single species. Pakistan harbors about 51.76% of the Acridomorpha species recorded for subtropical Asia, including 13.61% of the Caelifera, are endemic. Since the first checklist was published in 1990, which listed 39 species, hundreds of additional specimens from the region have been collected and databased, new species have been described, and the taxonomic status of some species has changed. Due to a lack of long-term studies for most localities, several species that were new at the time of collection are meanwhile described from other areas of Southeastern Asia. Specimen data from insect collections, databases, scientific literature, and unpublished records were compared to the original checklist. Our list includes three endemic species, 11 rare species, seven first-time reports, including five expected and 18 dubious records. Additionally, there are a few species from protected areas, although no consistent analysis has yet been done on species restricted to protected areas in Pakistan. A detailed account of subfamilies, endemic and rare species, and those anticipated to occur in Pakistan is also presented. This checklist provides baseline data for researchers and the public, strengthening the pest framework for management.

Revisiting an Old Issue: Sex Identification of Short-eared Owls (Asio flammeus) at an Asian Wintering Site

Abstract At wintering sites of the migratory Short-eared Owl (Asio flammeus) in subtropical Asia, behavioral interactions between males and females are limited, and the body mass and plumage features between the sexes overlap significantly. Thus, sexing the species morphometrically for research and conservation activities is difficult. We aimed to develop a quantitative method for sexing Short-eared Owls, and we here present a new formula to do so using plumage features. We used a total of 198 Short-eared Owls (163 from bird rescue efforts at 15 airports and 35 preserved specimens from a museum in Taiwan) and carefully examined their morphological data and plumage images, then determined their sex using polymerase chain reactions of chromodomain helicase DNA-binding protein genes on sex chromosomes or gonad inspection. Eight of the ten traits we evaluated differed significantly between males and females. Females had a greater number of cross bars on primaries, secondaries, and outermost tail feathers; a higher proportion of yellowish-brown underwing coverage; and larger measurements in head length, bill length, tarsus length, and body mass. The best-fit model suggested simplifying the formula to just the proportion of the yellowish-brown underwing coverage, which provided sexing accuracy exceeding 95.9% for the 49 live individuals in the test data set and 94.3% for the 35 preserved specimens. This formula addresses the challenges posed by ambiguous individuals in the wintering region and offers an efficient and accurate means for sexing Short-eared Owls when DNA or gonad inspection is unavailable.

The influence of climate change on the sesame yield in North Gondar, North Ethiopia: Application Autoregressive Distributed Lag (ARDL) time series model

Sesame is a major annual oil crop that is grown practically everywhere in tropical and subtropical Asia, as well as Africa, for its very nutritious and tasty seeds. Rising temperatures, droughts, floods, desertification, and weather all have a significant impact on agricultural production, particularly in developing countries like Ethiopia. Therefore, the main objective of this study is to examine the influence of climate change on the sesame yield in North Gondar, North Ethiopia, by using the autoregressive distributed Lag (ARDL) time series model. This study employed climate data from the Bahirdar Agrometeorological Center and secondary data on sesame production from the Ethiopian Statistical Service, spanning 36 years, from 1987 to 2023. Autoregressive Distributed LAG (ARDL) includes diagnostic tests for both short- and long-term autoregressive models. The results for the long-run and short-run elastic coefficients show a significant positive association between temperatures and sesame yield. Sesame yield and rainfall have a significant negative long-run and short-run relationship in North Gondar, North Ethiopia. ARDL results confirm that temperature and rainfall have significant effects on sesame productivity. Temperature had a considerable favorable effect on sesamen production, but rainfall had a negative effect in North Gondar, Ethiopia. Based on the evidence acquired from our study, we made several policy recommendations and suggestions to government officials, policymakers, new technologies, researchers, policy development planners, and other stakeholders in order to develop or implement new technology to halt its production and direct adaptation measures in light of the certainty of global warming and the characteristics of climate-dependent agricultural production.

Biphyly of the genus Wendlandia and establishment of a new tribe Clavistigmateae and a new genus Clavistigma of Rubiaceae from Asia

AbstractWendlandia, as currently circumscribed, is a genus of Rubiaceae comprising about 90 species mainly in tropical and subtropical Asia. By sampling species from all four series (Clavigerae, Euexsertae, Montigenae, Subinclusae) and all tribes in the subfamily Dialypetalanthoideae, we examined the monophyly of Wendlandia based on phylogenetic reconstruction using the nuclear ribosomal internal transcribed spacer and four plastid DNA regions. Wendlandia was resolved as biphyletic, consisting of two distantly related lineages that correspond to the monotypic series Clavigerae (Wendlandia pendula), sister to the Chinese endemic genus Trailliaedoxa, and a clade containing the remainder sampled members of Wendlandia. Based on the isolated phylogenetic position of W. pendula and its unique morphological characteristics compared to the recognized tribes of the Vanguerieae alliance, we herein erect a new monotypic genus, Clavistigma, and a new tribe, Clavistigmateae to accommodate the unique species. The secondary pollen presentation and the unique seed morphology were firstly described for the species. The divergence time between Clavistigma and Trailliaedoxa was dated back to 13.8 mya, coinciding with the climate change in northwestern Yunnan driven by the uplift Tibet Plateau and the river incision in the Hengduan Mountains during the Miocene and Late Pliocene.

Antibacterial Activity of lemongrass plant (Cymbopogan citratus) against pathogens

From the traditional health care system, we use plants as a good source of medicine/drugs. They have been an essential part of traditional health care system as cure or food supplements. Lemon grass (Cymbopogon Flexuosus and Cymbopogon Citratus) is a native aromatic tall sedge/grass belonging to family (Poaceae / Gramineae) with diverse medicinal value and grown in many parts of tropical and subtropical south east Asia and Africa. It was grown in India a century back and now commercially cultivated in different parts of India (Jharkhand, Bihar, UP). The oil has been found to possess bactericidal, anti-bacterial and anti-fungal properties comparable to Penicillin in its effectiveness. The purpose of study was to find the antibacterial activities of the lemongrass plant Cymbopogon citratus. The crushed leaves of selected plant were extracted with methanol and solvent extracts were evaporated for dryness with help of rotary Incubator. Remaining dry residue was dissolved in (E- Ethanol, Cl- Chloroform, A- Acetone, C- Control) and the leaf sample in four different solvents was applied for its antibacterial action. The antibacterial screening of the selected extracts was determined by the Kirby-Bauer’s Disc diffusion technique on the following bacteria- Pseudomonas aeruginosa and Bacillus subtilis. The maximum zone of inhibitions was noted with solvent ethanol (11mm) against plate 1(Pseudomonas aeruginosa) and 12mm against plate 2(Bacillus subtilis). The sample dissolved in ethanol showed the maximum zone of inhibition followed by chloroform and least with acetone against both the pathogens.

Review of the high bed–low ditch system as an alternative to lowland paddy in tropical and subtropical Asia

Many forms of traditional raised bed systems could be found around the world. Several of them have been identified as Globally Important Agricultural Heritage Systems (GIAHS) sites by Food and Agriculture Organization of the United Nations. Unlike traditional raised bed systems with similar structures in the Americas, the high bed–low ditch (HBLD) system in tropical and subtropical Asia, which is originated and developed from rice production, has been playing an important role in enhancing food security and maintaining farmer livelihood for centuries. Moreover, products provided by HBLD system are not only important for the livelihood of the local farmers, but also important for people living in the nearby towns and cities especially for vegetable and fruit supply. In this system, the ditches or sunken beds can be used to lower the groundwater table, retain nutrients and soil particles washed from the bed, grow rice or aquatic vegetables, and raise fish or shrimp. The HBLD system can also help to reduce salinity in coastal lowlands due to the presence of ditches. The raised beds can be used to grow various upland crops. Compared with rice monocropping, the adoption of HBLD system significantly improves the cropping intensity, productivity, employment, and income of farmers. Famers’ long-term practices fully demonstrate that this system is a type of sustainable agriculture with strong adaptability to the changes of natural environment. However, it should also be noted that the large-scale development of HBLD systems is not simply dependent on natural conditions, but is also determined by specific socioeconomic factors, such as good transportation facilities, a well market system, and a sufficient supply of labor. As a model of equilibrium between food production and high levels of biodiversity maintenance, the HBLD system is an important agricultural heritage system with global significance, and it should be well preserved and utilized in new ways to realize its important multiple functions under conditions of rapid urbanization in lowland and coastal regions.

A Taxonomic Revision of Indo-Burmese Trichodesma R. Br. (Boraginaceae)

The genus Trichodesma, occurring in tropical and sub-tropical Asia, Africa and Australia has about 45 species. The area taken up for revision is India, Bhutan and Burma. C. B. Clarke in Hook. f. FI. Brit. India described 5 species and 1 variety from this area. In this paper 7 species and 2 varieties have been described.

A Review on Ethnobotany, Phytochemistry and Pharmacological Activities of Euphorbia antiquorum L.

Euphorbia antiquorum L. is a small plant in the Euphorbiaceae family that is found primarily in tropical and subtropical Asia. It has a long tradition of being utilized in Chinese, Ayurvedic, and other traditional systems for a variety of ailments. To date, More than 116 bioactive constituents were isolated from Euphorbia antiquorum, with diterpenoids being the most abundant. Extracts and isolated chemicals from various portions of the plant have demonstrated significant pharmacological activities such as anti-inflammatory, analgesic, antidiabetic, anticancer etc. It is necessary to conduct an in-depth investigation of the phytochemicals along with the pharmacological properties of E. antiquorum. This review summarised the knowledge of ethnobotany, phytochemistry and pharmacological activities of the plant which will provide a better understanding to clarify the traditional uses of the species and its relation to modern pharmacology which will ultimately pave the way for its clinical application.

The complete chloroplast genome assembly of Amorphophallus tonkinensis Engler and Gehrmann 1911 from southwestern China

Species in the Amorphophallus genus are important cash crops in many tropical and subtropical Asian countries. Although several molecular markers have been employed to determine relationships and assess genetic variation in the Amorphophallus genus, some conflicts remain in infrageneric classification and evolution. To aid in the phylogenetic research of the Amorphophallus genus, we collected one sample of Amorphophallus tonkinensis Engler and Gehrmann 1911 from southwestern China. We assembled the first chloroplast genome of this species using high-throughput sequencing. The assembled genome was 169,341 bp long with a typical quadripartite structure (GenBank accession number: PP234804). The lengths of the large single-copy region, small single-copy region, and two inverted repeats were 90,705 bp, 15,640 bp, 31,498 bp, and 31,498 bp, respectively. We annotated 129 genes across the chloroplast genome of A. tonkinensis. The phylogenetic trees suggested that the Amorphophallus species distributed in continental Asia split into two main clades. The chloroplast genome reported in our study provided valuable genomic resources for the future phylogenetic research of the Amorphophallus genus.

Strangers like me: birds respond equally to a familiar and an unfamiliar sentinel species' alarm calls, but respond less to non‐core and non‐sentinel's alarm calls

Alarm signals have evolved to communicate imminent threats to conspecifics but animals may also perceive other species' alarm displays to obtain adaptive information. In birds, mixed‐species foraging flocks are often structured around a focal sentinel species, which produces reliable alarm calls that inform eavesdropping non‐sentinel heterospecifics about predation risk. Ongoing work has revealed that several species can recognize the alarm calls of certain sentinel species even without prior encounters, including when these are from distant biogeographic regions. Similar work has yet to examine whether naive subjects' responses to unfamiliar sentinel alarm calls differ from responses to non‐sentinel alarm calls. Here we played the alarm calls of three subtropical Asian bird species that participate in mixed species flocks, to temperate North American birds. Birds responded most to the alarm call of an allopatric core sentinel and a local sympatric sentinel control species, less so to an allopatric non‐core sentinel, and least so to an allopatric non‐sentinel and a negative control stimulus. These patterns provide evidence that broad phylogenetic and geographic recognition is a pertinent aspect of sentinel alarm calls in general.

Phytochemical and Pharmacological Review of the Genus Antidesma

Background Antidesma is a large genus consisting of around 100 species, which are widely distributed in the tropics and subtropics of Asia, some species can be found in Africa, the Pacific islands, and Australia. The uses of Antidesma plants range from food (for juice, jam, and red wine production) to medicinal purposes (for treatment of indigestion, pneumonia, menstrual regulation, and osteoarthritis). Methods The review was conducted by gathering relevant literature from secondary databases, including Web of Science, Google Scholar, and PubMed, as well as specialized books and websites. Results There have been more than 140 compounds reported as chemical constituents of the genus Antidesma, which mainly belonged to alkaloid, phenolic, flavonoid, lignan, and terpenoid classes. The high content of phenolic compounds was found in A. bunius and A. thwaitesianum fruits, which also correlates with the potential anti-oxidant activities of respective plants. Besides that, the antibiotic, antifungal, and anti-inflammatory activities, as well as effects on metabolism were also investigated and reported. Conclusion The plants of the Antidesma genus have a wide range of applications in food and medicine. The published results have shown that the genus is a precious source of bioactive natural compounds, which was shown beneficial for preventive medicine. Further research is required to promote the application in the healthcare system.

Premna integrifolia: A Review on the Exploration of its Potential Pharmacological and Therapeutic Properties

Abstract: Several Premna species can be found over the entire tropical and subtropical regions of Australia, Asia, and Africa. Many conventional herbal preparations using P. integrifolia (Lamiaceae) have been reported for their potential health advantages. The P. integrifolia is taxonomically ambiguous because of the wide variation in specimens obtained from various geographic locations. The plant is extensively used to treat immune-related disorders, skin conditions, inflammatory conditions, and stomach issues. The root of P. integrifolia is broadly utilized in the manufacture of Ayurvedic pharmaceutical products, such as Dasamula Kvatha and Chayawanprash Avaleha. It has also been identified to have antibacterial, hepatoprotective, and antifungal properties. The current study aims to investigate the antioxidant and cytotoxic activity of P. integrifolia against various cancers, as well as its antiinflammatory activity, antidiabetic, cardiac-stimulant, anti-obesity, hepatoprotective, immunomodulatory, analgesic, antiarthritic, antiparasitic, and wound healing activity, as well as the presence of various secondary metabolites in different parts of the plant used in a variety of formulations.

Climate control on the channel morphodynamics of the Sittaung River, Myanmar

The spatio–temporal development of a meandering river is controlled by its channel morphodynamics. In regions of rapid channel evolution, understanding the driving factors of meander migration is crucial in forecasting the rate and extent of morphological change. Sediment supply and fluvial discharge are the primary influences on migration rate, however climate oscillations are also integral in indirectly regulating migration rate through their control of regional precipitation, as well as the monsoon season of sub-tropical Asia. Despite this, an in-depth investigation into the impact of climate oscillations on meander bend migration remains undocumented. This study presents a satellite-based analysis of multi-decadal climatic forcing on the migration rate of the Sittaung River in Myanmar, through interpretation of the El Niño Southern Oscillation (ENSO). The mode of ENSO exerts significant climatic control on the migration rate of the meandering channels of the Sittaung River, with low-to-average migration rates recorded during dry El Niño events and peak migration rates observed during wet La Niña events. However, this climatic signal may have been obscured by certain local environmental conditions. In cases where meanders faced geological basement, the basement rock inhibited their migration through extension, forcing more rapid migration by way of seaward translation. Consequently, these translating meanders developed to be more elongate, with lower curvatures. Meanders downstream of the approximate tidal limit were less downstream skewed, indicative of tidal modulation, potentially obscuring the impact of fluvially driven climate forcing. Additionally, downstream of a major confluence, the input of sediment and fluvial discharge may have been regulated by upstream anthropogenic activities such as mining and dam construction, leading to greater variability in migration rate downstream of this confluence and further obfuscation of the climate signal.