Journal of Tropical Biodiversity and Biotechnology

Understanding The Current Knowledge and Potential Research of Indonesia's Only Protected Amphibian: The Bleeding Toad (Leptophryne cruentata)

Rizki Kurnia Tohir — 2025-01-09

Globally, amphibian populations are facing a substantial decline attributed to environmental degradation and lack of public attention. Indonesia, which one of countries with the high number of amphibian species in the world, paradoxically holds the record for the highest number of data-deficient amphibians. Indonesia currently has only one protected species, the bleeding toad (Leptophryne cruentata) also categorized as Critically Endangered. Considering this, our study undertakes a comprehensive review of bleeding toad research, highlighting research gaps and identifying potential topics for future investigations. In this study, we used an electronic database to acquire relevant studies aligned with our research objectives. The literature collection process involved the utilisation of the Publish or Perish (PoP) and manual internet searches. Our documentation reveals limited literature on bleeding toads, comprising only 20 reviews, with a notable prevalence of grey literature. This underscores the critical endangerment of bleeding toads, coupled with their neglect in research endeavours. Furthermore, our examination presents limited information on crucial aspects, such as taxonomy, morphology, geographical distribution, habitat characteristics, encounter records, behaviour, protection status, threats, and bioprospecting. The research gap is exceptionally high, with only two out of the 11 research topics attaining sufficient research status. Our findings underscore the urgent need for further research in this area. We identified at least 18 potential research areas that were essential for completing the baseline data. These findings serve as a valuable resource for researchers and policymakers seeking to address the critical endangerment of bleeding toads and to formulate effective conservation strategies.

Antifeedant Activity of Limonoids from the Seeds of Lansium domesticum Corr. Against Subterranean Termite Coptotermes curvignathus

Rudiyansyah — 2025-01-10

Lansium domesticum is one of Meliaceae plants produces limonoids with various biological activities, except for anti termites. Seven limonoids, dukunolides A-D (DA-DD), F (DF), and langsatides A-B (LA and LB), each previously isolated from the seeds of L. domesticum and prepared at 5 %, together with methanol root extract (MRE) 5 % were evaluated for insecticidal activity against Coptotermes curvignathus. Fifty workers and five soldiers of C. curvignathus were tested in a No-Choice Test to determine which limonoid was the most active. Dukunolides A-D, F, langsatides A-B, and MRE showed weaker antifeedant activity than the regent 50sc (positive standart, 8.04 %), except for dukunolide B (DB) that was stronger antifeedant activity, with a 7.28 % paper weight loss and 33.3 % mortality against C. curvignathus. Conclusion, this study showed limonoid compounds that were isolated from the seeds of L. domesticum could be developed for antitermite drugs.

Enhanced Antibacterial Potential of Fractionated Bioactive Compounds Isolated from Endophytic Nigrospora oryzae UILRZ1 in Ocimum gratissimum

Rahmat Folashade Zakariyah — 2025-01-10

The recurring global health challenges due to antimicrobial resistance require an impulsive response to search for alternative drugs with strong activities against multidrug-resistant pathogens. This study evaluated and screened endophytic fungi of strong antibacterial potential from Moringa oleifera and Ocimum gratissimum. Primer pairs of ribosomal DNA's internally transcribed spacer regions (ITS1 and ITS4) were used to determine their evolutionary relationships. A principal component analysis (PCA) biplot was used to identify the most effective endophyte at a 95% confidence level (P˂0.05). Improved culture conditions for the production of bioactive metabolites was done using the Taguchi design of experiment. Considering PCA biplot analysis, Nigrospora oryzae UILRZ1 from Ocimum gratissimum was most effective against selected pathogens. Production of metabolites was optimum at pH 5, 0.3 % (w/v) protein, 6-day inoculation time, and 4-plug inoculum, while variable of highest contribution was percentage of protein used. The column and thin layer chromatography were used to fractionate the extracts after optimization of production conditions while GCMS analysis was adopted to identify the chemical compounds. The crude extract's minimum inhibitory concentration (MIC) for chosen test microorganisms was 256 μg/mL prior optimization; while fractions of partially purified optimized extract of Nigrospora oryzae UILRZ1 showed enhanced antibacterial activity against Staphylococcus aureus with a MIC of 64 μg/mL. Efficient synthesis of bioactive metabolites was significant in the enhanced antibacterial activity against S. aureus.

The Distribution and Behaviour of Lesser Whistling-Duck (Dendrocygna javanica) at Lang Sen Ramsar site in Mekong Delta Vietnam

Le Diem Kieu — 2025-01-13

This study aimed to investigate the distribution, behaviour, potential food, competitor, and potential predator of Lesser Whistling-Duck (Dendrocygna javanica) by direct observations at six sub-zones in the Lang Sen Ramsar site in the south of Vietnam, from September 2021 to August 2022. Two hundred sixty nine (269) individuals of the D. javanica were seen on site mainly in pairs and small flocks. The survey showed that Lesser Whistling-Duck often appears in areas with water lettuce and duckweed at sub-zone 9, wild rice and lotus fields at sub-zone 12, and low water level fluctuation at sub-zone 5 in the early morning and late afternoon. The food source of Lesser Whistling-Duck in the reserve Lang Sen are mainly plants (duckweed, water lettuce, young shoots or seeds of lotus, water lily, water hyacinth, and wild rice) and small animals (snail, worm, shrimp, fish, and insect). This bird species is relatively sensitive to environmental influences and their ability to perceive, reflect, and make sound depends on the size of flocks. The carnivores often damage the Lesser Whistling-Duck including black kite, greater coucal, lesser coucal, and python. They are also affected by competition for food and habitat of other waterbirds, activities of tourists, and people around the reserve. The result of observation of Lesser Whistling-Duck is a concern from new area, so it added the information on the distribution of the species, including behaviour, the potential food, competitors, predators, and human threats, which are important in managing the species.

Exploration the Potency of Copper and Dyes Multi-Resistant of Indigenous Bacteria Isolated from Cikijing River, West Java

Wahyu Irawati — 2025-01-20

Various types of textile dye have been reported to contaminate the Cikijing River, West Java, Indonesia due to its location within the industrial region of Rancaekek District. It has been understood that certain bacterial species develop copper resistance and dye decolourisation as a mechanism of stress adaptation. The study aims at isolating and characterising copper and dye resistance as well as decolourisation ability of bacteria isolated from the Cikijing River. Copper-resistant bacteria were isolated using a series dilution method on Luria Bertani media supplemented with the addition of 1-10 mM CuSO₄. Purified bacterial isolates were then tested for copper resistance onto LB agar medium supplemented with CuSO₄ concentrations ranging from 0 mM to 20 mM and decolourisation of various dyes. A total of 59 copper-resistant bacteria were successfully isolated, nine of them showed the highest copper resistance with a MIC value from 11 mM up to 16 mM CuSO₄ and resistance to 4 types of dyes up to 700 ppm. The 16S rDNA analysis showed that the nine isolates were Klebsiella sp., Klebsiella pneumoniae, Lysinibacillus boronitolerans, Lysinibacillus fusiformis, Bacillus proteoliticus, Pseudomonas stutzeri, Klebsiella variicola, Citrobacter freundii, and Klebsiella variicola. Out of nine isolates, five were found resistant to 5 mM CuSO₄ and decolourise Methylene Blue, Congo Red, and Basic Fuchsine dyes at a maximum concentration of 700 ppm.

Biodegradable Sheets from Dried Mycelia of Edible Mushrooms

Chairat Pattarasiripol — 2025-01-17

Due to its quick growth and biodegradability, mushroom mycelium has been used to create alternative materials. This study aimed to produce mycelium sheets from market-purchased edible mushrooms (Lentinus sp. and Pleurotus sp.). They were isolated and cultured in various liquid media. The production of four mycelium sheets was successful. After drying, the sheets of Pleurotus sp. using potato dextrose broth had the largest water contact angle. With a tensile strength, the sheet of Lentinus sp. using malt extract broth obtained the highest value. The dried mycelium sheet from Pleurotus sp. cultured on yeast extract broth had the greatest hardness value in the microhardness testing. After 7 days, the residual dry weight of the sheets in different conditions—soil burying, soil surface exposure, and water immersion—was less than 50% of the initial weight. This work has demonstrated the biodegradability of mycelium sheets.