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All Journal BIOTROPIA - The Southeast Asian Journal of Tropical Biology Biotropika Tropical Plantation Journal
Ida Bagus Gede Darmayasa
Biologi, Fakultas Matematika dan Ilmu Pengetahuan Alam, Universitas Udayana, Kampus Bukit Jimbaran
Agriculture, Biological Sciences & Forestry Biochemistry, Genetics & Molecular Biology Immunology & microbiology Veterinary

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THE THE EFFICACY OF BACTERIAL AND FUNGAL ANTAGONIST SUSPENSIONS IN CONTROLLING FOLIAR MILDEW DISEASE IN ZUCCHINI PLANTS: - Ramona, Yan; A. Line, Martin; Septiari, I Gusti Ayu Agung; Darmayasa, Ida Bagus Gede; Agung Panji Dwipayana, I Dewa; Shetty, Kalidas
BIOTROPIA Vol. 32 No. 2 (2025): BIOTROPIA Vol. 32 No. 2 August 2025
Publisher : SEAMEO BIOTROP

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11598/btb.2025.32.2.2448

Abstract

ARTICLE HIGLIGHTS- Diverse microbial antagonists can be used as alternatives to control foliar disease - Microbial agents offer zucchini protection against downy mildew causing microbes- Biocontrol agents effectively control mildew infection in zucchini plants- Diverse microbial antagonists have potential to control foliar disease in zucchini - New bio-based strategy supports sustainable crop disease management- Diverse microbial antagonists are promising for controlling mildew in zucchiniABSTRACTDowny mildew is recognized as a major constraint in zucchini production, caused by obligate fungal-like pathogens that thrive under humid conditions. In this study, the efficacy of selected bacterial (Lysobacter antibioticus Bali G, Pseudomonas corrugata SAJ6) and fungal (Trichoderma sp. Td22) antagonists was evaluated for the management of this foliar disease on zucchini plants as an alternative to chemical fungicides. The efficacy of these bacterial and fungal antagonists against a suspected downy mildew pathogen was assessed on zucchini leaves in a glasshouse. It was found that the antagonists provided 22 - 83% protection (P < 0.05) against the pathogen two weeks after application. However, the level of protection declined over time, with 46 - 60% of leaves infected five weeks after pathogen exposure, regardless of treatment. The combination of Trichoderma sp. Td22, the most effective agent, with either Lysobacter antibioticus Bali G, Pseudomonas corrugata SAJ6, or both, was observed to reduce its overall effectiveness. Survival of the biological agents on leaf surfaces was low, although prior research has indicated that survival may not be essential for sustained disease control. Further investigation is required to determine the potential role of these agents in inducing systemic acquired resistance in crops such as grapes and poppies. For commercial application, repeated treatments may be necessary to maintain disease management. Notably, the protection provided by Trichoderma sp. Td22 was found to be comparable to that of chemical treatments, representing a promising step toward more sustainable agricultural practices.
Antibacterial Activity Screening Of Bacterial Isolates Associated With Seaweed Eucheuma cottonii From Coastal Area In Buleleng, Bali Purnami, Pande Putu Christine Putri; Indraningrat, Anak Agung Gede; Darmayasa, Ida Bagus Gede
Biotropika: Journal of Tropical Biology Vol. 10 No. 2 (2022)
Publisher : Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/ub.biotropika.2022.010.02.07

Abstract

Seaweeds like other marine organisms develop a strong association with prokaryotic communities, especially bacteria. Many of these associated bacteria play an important role in synthesizing secondary metabolites which are beneficial for their host, especially against predation or infection. In Indonesia, Eucheuma cottonii is one of the seaweed species that has been cultivated widely.  However, only limited study has been reported on bacterial isolates and their antibacterial activity from E. cottonii.  Bacterial isolates from E. cottonii were cultivated in six agar media namely Zobell Marine Agar, Nutrient Agar, Plate Count Agar, ISP-1, ISP-2, and Starch-M protein agar. Cultivation of bacterial isolates yielded 23 isolates with nine bacterial isolates were classified as Gram-positive bacteria and 14 isolates were grouped among Gram-negative bacteria. All the bacterial isolates were screened for their antibacterial activity against six bacterial indicator strains namely Staphylococcus aureus ATCC 25923, Streptococcus mutans FNCC 0405, Escherichia coli ATCC 25922, and Klebsiella pneumoniae ATCC 700603 using perpendicular streak and agar block method. Six out of 23 bacterial isolates displayed antibacterial activity against at least one of the bacterial indicator strains. The bacterial isolate ISP1RL4 showed the highest antibacterial activity with average inhibition of  > 20 mm against all bacterial indicators. Overall, our result indicated the potential of bacterial isolates associated with E. cottonii as an antibacterial producer.
Antibacterial Activity and Preliminary Phytochemical Screening of Forest Chili Leaf (Piper caninum Bl.) Ethanol Extract against Staphylococcus epidermidis Shanzet, Flavia Fionessa Falenda; Darmayasa, Ida Bagus Gede; Suriani, Ni Luh; Wiadnyani, Anak Agung Istri Sri; Ho, Ting Seng; Rusdianasari, Rusdianasari; Mariani, Mariani
Tropical Plantation Journal Vol 3, No 1 (2024): TROPICAL PLANTATION JOURNAL
Publisher : Akademi Komunitas Perkebunan Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.56125/tpj.v3i1.34

Abstract

Forest chili leaves (Piper caninum Bl.) has a potential to become an alternative to conventional antibiotics. This study aims to determine the Minimum Inhibitory Concentration (MIC) of forest chili leaf extract, assess the Lethal Concentration (LC50), and analyze the phytochemical composition of the extract. This study also conducted a Completely Randomized Design (CRD) with four repetitions. The agar well diffusion method is used in this study with various concentrations such as T1 ethanol 96% (negative control), T2 (5% concentration), T3 (10% concentration), T4 (15% concentration), T5 (20% concentration), T6 (25% concentration), and T7 Ciprofloxacin 1% (positive control). Data were subjected to ANOVA at a significance level of 5% and further analyzed using Duncan's test. The results showed that all concentrations of forest chili leaf extract (P. caninum Bl.) exerted a statistically significant effect (P 0.05) against Staphylococcus epidermidis bacteria. The research found that the most effective concentration to inhibits S. epidermidis is at 25%, which generates an inhibitory zone of 25.38 ± 0.52 mm. The estimated MIC value for forest chili leaf extract against S. epidermidis was found to be 0.2%, producing an inhibitory zone of 6.38 ± 0.32 mm. Additionally, the calculated LC50 value was 0.26%. Phytochemical screening revealed the presence of various bioactive compound groups in the forest chili leaf extract, including alkaloids, flavonoids, phenols, tannins, and steroids.
The POTENTIAL OF LACTIC ACID BACTERIA, ISOLATED FROM SEVERAL SOURCES, TO INHIBIT THE GROWTH OF Candida albicans ATCC10231 Ramona, Yan; Darmayasa, Ida Bagus Gede; Dharmawan, Komang; Sudaryatma, Putu Eka; Teriyani, Ni Made; Batho, Yanuarius Felix; Inabuy, Fainmarinat Selviani
BIOTROPIA Vol. 31 No. 2 (2024): BIOTROPIA Vol. 31 No. 2 August 2024
Publisher : SEAMEO BIOTROP

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11598/btb.2024.31.2.1868

Abstract

ARTICLE HIGHLIGHTS- Lactic acid bacteria have potential to control candidiasis or Candida albicans. - The novelty of this study is to advance the potential of lactic acid bacteria to control candidiasis infection in human, with a view to develop novel LAB-based probiotic candidates with capability to inhibit/prevent infection by C. albicans, the causative agent of candidiasis.ABSTRACTThe main aims of this research were to isolate and identify potential lactic acid bacteria (LAB) inhibitory to Candida albicans. The LAB sources were kimchi, honey and vaginal secrete of healthy women. They were isolated with a view to develop a novel alternative method with reduced use of antifungal agents in the treatment of patients infected by such fungal pathogen. Isolation of the LABs was conducted by applying dilution spread method on de Mann Rogosa Sharpe agar (MRSA) medium supplemented with bromo cresol purple (BCP) indicator. Once purified, they were tested for antagonism against C. albicans in dual culture assays. LAB isolates that showed significant inhibition against the pathogen were identified using 16s rDNA sequences and their sequences were aligned with those of known sequences deposited at the Gene Bank (http://www.ncbi.nlm.nih.gov). The results showed that 46 among more than 100 LABs isolated in this study significantly inhibited the growth of C. albicans in the in vitro dual culture assays, and all showed resistance property to antifungal agent (fluconazole). This indicated that they all have potential to be synergically applied with reduced use of fluconazole in the therapy. The most potential isolates (10 isolates) were closely related to three LAB species, namely Lactobacillus paracasei, Lacticaseibacillus paracasei, and Pediococcus pentosaceus, based on their 16s rDNA sequence similarities with those deposited in the GenBank.
The THE POTENCY OF CINNAMON (Cinnamomum burmanni Blume) LEAF EXTRACT AS A BIOPRESERVATIVE AGENT FOR FOOD SAFETY OF SATE LILIT: - Darmayasa, Ida Bagus Gede; Ramona, Yan; Darmadi, Anak Agung Ketut; Suanda, I Wayan; Hani, Ni Luh; Shetty, Kalidas
BIOTROPIA Vol. 31 No. 2 (2024): BIOTROPIA Vol. 31 No. 2 August 2024
Publisher : SEAMEO BIOTROP

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11598/btb.2024.31.2.2165

Abstract

ARTICLE HIGLIGHTS- Cinnamon leaf extract combats E. coli in traditional Balinese food.- Natural preservative reduces harmful pathogens in sate lilit.- Cinnamon extract offers a safer alternative to synthetic preservatives.- Active compounds in cinnamon leaves inhibit bacterial growth.- Effective biopreservative for enhancing food safety and quality. ABSTRACTEscherichia coli O157:H7 contamination of the meat used in preparing sate lilit, a favorite traditional food in Bali, Indonesia, has been a great concern for both local people and foreigners. Although C. burmanni has been included in its spice ingredients, active compounds that play a significant role in this pathogen have limitedly been elucidated. The main objectives of this research were to investigate the potency of this plant to control contaminants and elucidate possible compounds that prevent such contaminants by applying the disk diffusion method and LCMS analysis, respectively. The results showed that the leaf extract of this plant inhibited the in vitro growth of E. coli O157:7, with minimal inhibitory concentration (MIC) and LC50 values of 4% and 2.59%, respectively. The LCMS analysis chromatogram showed that the plant extract's most active fraction produced nine peaks, representing nine possible active compounds. Among those, three compounds (Azoxystrobin, Stigmatellin Y, and 2-arachidonoyl glycerol) were suspected of contributing to control contamination, especially by E. coli O157:H7.
Co-Authors A. Line, Martin Agung Panji Dwipayana, I Dewa Anak Agung Istri Sri Wiadnyani Anak Agung Ketut Darmadi Batho, Yanuarius Felix Hani, Ni Luh Ho, Ting Seng I Wayan Suanda Inabuy, Fainmarinat selviani Indraningrat, Anak Agung Gede Komang Dharmawan Mariani Mariani Ni Luh Suriani Purnami, Pande Putu Christine Putri Putu Eka Sudaryatma Rusdianasari Rusdianasari Septiari, I Gusti Ayu Agung Shanzet, Flavia Fionessa Falenda Shetty, Kalidas Teriyani, Ni Made Yan Ramona