BIOTROPIA - The Southeast Asian Journal of Tropical Biology
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MICROSATELLITE-BASED GENETIC VARIATION IN Rhizophora apiculata AND Rhizophora mucronata FROM EAST KALIMANTAN
No full textARTICLE HIGHLIGHTS- Microsatellite markers were used to study population genetic variation in Rhizophora- Molecular systematic analysis showed moderate genetic diversity with low heterozygosity- Population genetic structure was dominated by within-population variation (AMOVA)- Phenetic analyses revealed weak clustering among Rhizophora populations- Genetic patterns supported connectivity within Rhizoporaceae populations in East KalimantanABSTRACTMangroves of the family Rhizophoraceae are pantropical, with the genus Rhizophora forming a major component of tropical mangrove ecosystems. Rhizophora apiculata and Rhizophora mucronata are widely distributed in the Paser region, Balikpapan Bay, and the Mahakam Delta of East Kalimantan, Indonesia. This study examined genetic diversity and population structure of both Rhizophora species using simple sequence repeat (SSR) markers. The results showed moderate genetic diversity but relatively low heterozygosity in both species. Most genetic variation occurred within populations, as indicated by AMOVA, while R. apiculata exhibited lower genetic differentiation among populations and lacked private alleles, and R. mucronata showed higher population differentiation and possessed private alleles, suggesting localized genetic variation. Cluster and principal coordinate analyses revealed extensive overlap among populations for both species, indicating weak population structure and ongoing gene flow across the study area. Overall, the findings suggest that populations of R. apiculata and R. mucronata in East Kalimantan function as genetically connected units rather than as strongly differentiated populations. These results highlight the importance of maintaining habitat connectivity and protecting genetically unique populations to support the long-term resilience and sustainable management of mangrove genetic resources in East Kalimantan
STRUCTURAL DYNAMICS OF BACTERIAL NITROREDUCTASE ENZYMES FROM A MINING-IMPACTED ENVIRONMENT IN SOUTH KALIMANTAN, INDONESIA: ARCHITECTURE FOR SUSTAINABLE CHROMIUM BIOREMEDIATION
No full textARTICLE HIGLIGHTS- New bacterial enzymes found in Indonesian soil can neutralize toxic chromium waste.- These unique bacteria show great promise for bioremediation in polluted mining soils.- One of the newly found enzymes from these bacteria has a superior, highly stable structure.- This superior stability is key, coming from a rigid core with flexible moving loops.- This research provides a molecular blueprint for engineering enzymes to clean up chromium.ABSTRACTHexavalent chromium [Cr(VI)], a soluble and carcinogenic industrial pollutant, poses a significant threat to both the environment and human health, necessitating effective remediation strategies. Microbial enzymatic reduction of Cr(VI) to its less toxic trivalent state, Cr(III), is a promising approach. However, growing evidence suggests that many enzymes involved in this process are flavin mononucleotide (FMN)-dependent reductases, which likely reduce Cr(VI) adventitiously via a reduced flavin intermediate, rather than through direct enzymatic catalysis. This study presents a comparative computational analysis of two novel FMN-dependent reductases, designated M2Cr10 and M54Cr10, derived from chromium-tolerant bacteria Acinetobacter radioresistens and Bacillus tropicus, respectively, which were isolated from Indonesian serpentine soil. Phylogenetic and sequence analyses classified both enzymes as members of the FMN-dependent nitroreductase superfamily. High-quality homology models were generated and validated, with over 95% of residues occupying the most favored regions of the Ramachandran plot, confirming their stereochemical integrity. Molecular docking simulations predicted strong binding affinities for the FMN cofactor, with binding energies of -7.1 kcal/mol for M2Cr10 and -8.1 kcal/mol for M54Cr10. These interactions are stabilized by a network of hydrogen bonds and hydrophobic contacts, with residue Tyr¹³¹ identified as a key anchor for the FMN isoalloxazine ring in both enzymes. Extensive 10-nanosecond molecular dynamics simulations revealed that the A. radioresistens M2Cr10 enzyme exhibits superior structural architecture characterized by greater global stability, as indicated by lower average root mean square deviation (RMSD) and solvent-accessible surface area (SASA). However, it also displays greater localized flexibility (higher RMSF) in functional loop regions critical for catalysis. This combination of a rigid scaffold and dynamic functional loops suggests that M2Cr10 may be a more robust and potentially efficient biocatalyst. These findings provide a detailed molecular blueprint for understanding the structural determinants of stability in FMN-dependent reductases and offer a rational basis for engineering these enzymes for more effective adventitious bioremediation of Cr(VI)
TICK-BORNE PATHOGENS DETECTION FROM TICKS INFESTING Malayopython reticulatus (REPTILIA: PYTHONIDAE) SNAKES IN INDONESIA
Full text linkArticle Highlights:- A total of 38 ticks were collected from M. reticulatus, comprising 13 A. helvolum and 25 A. varanense.- Spotted fever group Rickettsia spp. (7.89%) and reptile-associated Borrelia sp. (2.63%) were detected in male Amblyomma helvolum ticks collected from Malayopython reticulatus snakes in Indonesia.- Snake-associated ticks may harbor emerging pathogens, underscoring the importance of tick surveillance in reptiles for early disease detection and zoonotic prevention.
Abstract: Ticks are important arthropod vectors of numerous diseases in humans and animals. Furthermore, ticks are also established vectors and reservoirs of pathogens important to wildlife and human health. Rickettsia and Borrelia are two genera of bacteria that may be transmitted by ticks, and some pathogenic species are zoonosis. This research investigated the prevalence of Rickettsia spp. and Borrelia sp. in Amblyomma helvolum and Amblyomma varanense ticks fed on Malayopython reticulatus and Python bivittatus snakes in Indonesia. A total of 38 ticks were collected from three M. reticulatus snakes, while no ticks were found on the P. bivittatus snake. The 38 ticks consisted of 13 individuals A. helvolum and 25 individuals A. varanense. PCR analysis revealed that three (3/38; 7.89%) male A. helvolum ticks were positive for spotted fever group Rickettsia spp. and one (1/38; 2.63%) male A. helvolum tick was positive for a reptile-associated group Borrelia sp. Although the overall prevalence of tick-borne pathogens was low, this study underscores the importance of monitoring the prevalence and prevention of tick-borne diseases. Surveillance of ticks infesting reptiles can facilitate the early detection of disease transmission to both animals and humans. These findings also suggested that snake-associated ticks may harbor emerging tick-borne pathogen
PREDICTING THE FUTURE DISTRIBUTIONS OF ENDEMIC RATTAN CALAMUS JAVENSIS BLUME UNDER CLIMATE CHANGE SCENARIOS CMIP 5 RCP 8.5 IN 2050 AND 2070 IN WEST JAVA: Predicting the future distributions of endemic rattan
No full textHIGHLIGHTSInformation on how climate change can shape Calamus javensis distributions is still lackingThe study used SDM with RCP 8.5 scenario for the years 2050 and 2070Suitable habitats for C. javensis are expected to decline by approximately 46.34%Suitable habitats for C. javensis are expected to be concentrated in western parts of West Java
ABSTRACTC. javensis is an endemic rattan plant in West Java. While the information on how climate change can shape C. javensis distributions and how C. javensis can cope climate change conditions is still lacking. This information is required considering that C. javensis is an endemic plant in West Java. Then, the purpose of this study is to model the climate change impact on future C. javensis distributions. The study using species distribution modeling (SDM) covering nine locations across West Java with RCP 8.5 climate change scenario for year 2050 and 2070. The result show under the scenarios of climate change, the only appropriate habitats for C. javensis were concentrated in western parts of West Java. Within time series and climate change scenarios, the suitable habitats categorized as very high suitable for C. javensis were estimated to decline. From 2050 to 2070, suitable habitats for C. javensis will decline by around 46.34% from 1025 to 550 km2 in 2070
OPTIMIZATION OF Eucalyptus pellita F. Muell GROWTH USING ARBUSCULAR MYCORRHIZA FUNGI AND COFFEE HUSK COMPOST ON SUBSOIL MEDIA
No full textHIGHLIGHTS- Mycorrhizal fungi and coffee compost boost tree seedling growth in poor subsoil- The method helps grow Eucalyptus faster for land restoration efforts.- Reduces the need for topsoil, promoting sustainable nursery practices.- An optimal mix of mycorrhizal fungi and compost supports robust Eucalyptus development.ABSTRACTArbuscular mycorrhizal fungi (AMF) and coffee husk compost are used to improve the physical and chemical conditions of the subsoil, enhancing plant growth. This study aimed to evaluate the response of plant growth and analyze the effect of AMF and coffee husk compost doses on optimal growth acceleration of Eucalyptus pellita seedlings in subsoil media. Seedlings were grown in subsoil with varying doses of AMF (0; 2.5; and 5 g/polybag) and coffee husk compost at different ratios (1 : 1; 2 : 1; and 3 : 1). AMF and coffee husk compost application significantly affected all parameters of seedling growth, including height, number of leaves, diameter, biomass, seedling quality index, and shoot/root ratio. Inoculation of AMF at a dose of 2.5 g/polybag and subsoil media enriched with coffee husk compost at a ratio of 2 : 1 was an efficient treatment to increase the seedling growt
REMNANT OF THE DRYLAND COASTAL VEGETATION OF THE SONGKHLA LAKE BASIN, SONGKHLA, THAILAND
No full textHIGHLIGHTSThis article identifies and characterizes three native plant communities in the Songkhla Lake Basin, highlighting their distinct species composition, coastal zonation patterns, and ecological value. It reveals high plant diversity across remnant dryland coastal habitats and documents key native species that define each community type. The study emphasizes the negative impacts of human activity and land policies on native vegetation and offers baseline floristic data that support conservation, ecological restoration, and sustainable land-use planning.ABSTRACTThe remnant dryland coastal vegetation of the Songkhla Lake Basin, Songkhla, Thailand, was investigated in this study. Twenty vegetation plots were established to represent each vegetation subtype. Using Braun-Blanquet cluster analysis and the Jaccard similarity index, the vegetation was classified into three distinct communities: (1) the Coastal Woodland Community, located farthest inland and dominated by Dipterocarpus alatus Symington; (2) the Coastal Scrub-Shrubby Tree Community, situated inland from the coastal zone, with Dipterocarpus chartaceus Symington, Neolitsea zeylanica (Nees & T. Nees) Merr., and Psychotria asiatica L. identified as dominant species; and (3) the Coastal Scrub Community, occurring near the shoreline and characterized by densely clustered vegetation dominated by Mischocarpus sundaicus Blume, Planchonella obovata (R.Br.) Pierre, and Vitex pinnata L. Vegetation profiles for each community were delineated. Significant degradation and decline of native plant communities in the Songkhla Lake Basin have been caused by conservation activities involving the introduction of fast-growing non-native species and by governmental land tax policies
ENHANCING THERAPEUTIC SECONDARY METABOLITE PRODUCTION BY COMPREHENSIVE BIOSTIMULANT INTEGRATION: HARMONIZING PLANT AND MICROBIAL EXTRACT: Significance of Microbial and Non-microbial Bio-stimulants
No full textHIGHLIGHTS- Integrative insights into Non-microbial and Microbial Biostimulants.- Focus on enhancing significant secondary metabolites and plant quality.- Comprehensive analysis of sustainable agricultural practices.- Future scope and positive research directions in Biostimulants.- Role of biostimulants in stress resilience.
ABSTRACTIn recent decades, biostimulants have become recognized as organic alternatives for promoting sustainable agricultural practices, extensively applied across agriculture, horticulture, ornamental plants, and greenhouses. Unlike biofertilizers and biopesticides, biostimulants are derived from plants, animals, and microbes and classified by their chemical composition. They are primarily divided into non-microbial and microbial biostimulants. Non-microbial biostimulants include humic substances, seaweeds, Chitosan, protein hydrolysates, amino acids, and inorganic compounds, while microbial biostimulants consist of plant growth-promoting bacteria and beneficial fungi. This review paper consolidates the recent positive effects of biostimulants on sustainable agriculture and outlines potential research areas for the future. Biostimulants serve as biocontrol agents that promote plant growth and development, also reported to enhance the production of valuable industrial therapeutic secondary metabolites. Traditionally, plants with medicinal properties have been used for natural remedies, and biostimulants aim to elevate the secondary metabolite content in these therapeutic plants. Additionally, the significance of both microbial and non-microbial biostimulants is touched upon. A review of existing literature indicates that biostimulants significantly boost nutrient absorption, enhance resilience against abiotic stress, replenish nutrients, and improve soil quality
EFFICACY OF THE BIOFLOC SYSTEM WITH THE ADDITION OF CHITOSAN ON TIGER PRAWN (Penaeus monodon) PRODUCTIVITY
Full text linkHIGHLIGHTS- Biofloc technology with chitosan addition improved the growth performance of Penaeus monodon, increased floc volume and heterotrophic bacteria, and reduced Vibrio-like bacteria.- Biofloc technology with chitosan addition enhanced water quality and microbial community, supporting P. monodon growth.P. monodon in a biofloc system with chitosan had higher weight gain, growth rate, and survival rate. - The study provides insights for sustainable intensive shrimp farming using biofloc technology.- Findings contribute to improving productivity and maintaining environmental conditions in shrimp aquaculture.
ABSTRACTPenaeus monodon farming failures are often found from Post Larva\u27s initial distribution phase until harvest. High mortality rates of P. monodon post-larvae are often observed after stocking. A disease attack in the second month during the rearing period eventually causes failure in extensive ponds. The primary objective of this research was to investigate the impacts of adding chitosan on on the yield of P. monodon within a biofloc technology (BFT) culture system. The experiment was carried out in triplicate using three distinct treatment options. Post-larval P. monodon (PL-10) that were visually healthy and disease-free were obtained from a hatchery and then stocked at a density of 40 individuals per 100 liters. Shrimps, and fed a commercial diet four times daily for 40 days. A statistically significant difference was observed (p-value < 0.05) in weight gain (0.213-0.299 g), average daily growth (0.0054-0.0074 g/day), and specific growth rate (13.4-14.3 %/day) of shrimp were found among the treatments. The inclusion of chitosan in the biofloc system led to a prominent rise in floc volume and heterotrophic bacterial populations, while simultaneously reducing the number of Vibrio-like bacteria (VLB) colonies. No notable variations were noted in food conversion ratio (FCR), total length, survival rate, total nitrite-N, nitrate-N, and total ammonia nitrogen levels. Biofloc technology supplemented with chitosan is found to boost the growth rate of P. monodon by enhanced both water quality and the microorganisms present within it, according to the study
ENHANCING CALLUS FORMATION IN TAPAKTUAN PATCHOULI THROUGH IN VITRO OPTIMIZED COMBINATIONS OF PGR
Full text linkArticle Highlight- Different varieties of Patchouli exhibited different growth pattern as well as in vitro culture- In order to induce callus, it has been determined that the combination of regulators is necessary.- Benzylaminopurine has been identified as a potential regulator that could be used to further develop the patchouli callus of Tapak Tuan.
Abstract: Patchouli is known for its highly demanded essential oil. The Patchouli Tapaktuan variety is the most widely cultivated by local farmers in Aceh due to its high oil yield. Currently, the study and propagation of patchouli through a biotechnological approach is being developed, one of which is in vitro culture method. In this method, suitable Plant Growth Regulators (PGR) are being observed to enhance the growth of the explant. PGRs are synthetic compounds that are added to media in plant tissue culture to stimulate plant growth. This study aimed to analyze and optimize the effect of benzylaminopurine (BAP), thidiazuron (TDZ) combined with Naphthaleneacetic acid (NAA) on the growth of Tapaktuan patchouli leaf callus. This study was carried out by using a completely randomized design with seven treatments. Each treatment was replicated four times and each replicate contained three explants. The concentrations used were BAP 0.75 mg/L, TDZ 1 mg/L, and NAA in the 0.25 - 0.75 mg/L range. According to this study, combining BAP and NAA was the most effective for inducing callus in Tapaktuan patchouli leaves. The combination of BAP 0.75 mg/L + NAA 0.5 mg/L (treatment A2) was the most effective for inducing callus formation. This treatment resulted in the quickest callus development, the highest percentage of callus formation, and the largest callus diameter. Explants cultured with BAP produced a greenish-yellow callus having the potential for organogenesis culture, which could produce shoots having the ability for producing mass plantlets
DIVERSITY, MORPHOMETRY, AND POPULATION ABUNDANCE OF SEA URCHIN (Tripneustes gratilla) IN NORTH LOMBOK
Full text linkArticle Highlights- The highest absolute abundance of sea urchin Tripneustes gratilla was observed in August 2023- In 2024, the low absolute abundance of Tripneustes gratilla and the decline of sea urchin species diversity in North Lombok prospectively indicated overharvesting.- The number of gleaners and the gleaning activity conducted by local villagers prospectively harm seagrass meadows, especially on Tripneustes gratilla abundance
AbstractSea urchin Tripneustes gratilla is commonly found in tropical shallow water-seagrass beds and is consumed for its roe in Southeast Asia. This study recorded five sea urchin species in the study area: Tripneustes gratilla, Pseudoboletia maculata, Salmacis bicolor, Salmacis sphaeroides, and Maretia planulata, with T. gratilla being the most abundant. The highest absolute abundance of T. gratilla was observed in August 2023, at 0.30 ind./m2, while from May to July 2024, it declined to 0.02 ind./m2. The mean diameters of T. gratilla ranged from 37.59 mm to 44.16 mm between August and October 2023 and from 17.39 mm to 48.45 mm between May and July 2024, having wide range of the mean weight. In September 2023, sea urchin with a test diameter of 35.0 – 39.9 mm were the most frequent to be found. This study provided baseline data on T. gratilla harvested from the seagrass habitat by the local community in North Lombok and highlights the potential for overharvesting in the area