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The global increase in multidrug-resistant (MDR) bacterial infection has rapidly gained concern globally. This study aimed to investigate antibacterial and antibiofilm potential of 25 soil actinomycete strains against MDR strains including Escherichia coli strain M4, Pseudomonas aeruginosa strain M19, Klebsiella pneumoniae strain M19, Bacillus subtilis strain M18, and Methicillin Resistant Staphylococcus aureus (MRSA). In this study, three actinomycete isolates encoded APM-7, APM-11, and APM-21 showed a strong and broad antibacterial spectrum. The minimum inhibitory concentration (MIC) of extracts derived from these isolates was ranged from 78 μg/ml to 10,000 μg/ml. In addition, The extracts also displayed significant biofilm inhibition values ranging from 6.06 to 72.4%. Based on the results, APM-21 extract had the best antibacterial and antibiofilm activities with the strongest values against MRSA. According to the nucleotide sequencing of the 16S rRNA gene, APM-7, APM-11, and APM-21 strains possessed similar identities with Streptomyces cyaneus, Streptomyces coerulescens, and Streptomyces panayensis, respectively. Based on Liquid Chromatography Tandem-Mass Spectrometry (LC-MS/MS) analysis, two antibacterial compounds, namely rancimanycin III, and enteromycin were detected in all those three extracts. Interestingly, APM-21 extract also contained two prominent antibacterial substances including paramagnetoquinone C, and caerulomycin I, suggesting their contribution to the most potential activities. Moreover, new insights were provided into a promising candidate for use in an active compound combating strategy to control MDR bacterial strain infection. [ABSTRACT FROM AUTHOR]

Aglaia foveolata Pannell (A. foveolata) is a type of plant that has many benefits, including the skin, leaves, roots, and seeds as medicinal ingredients. The potential of this plant is inseparable from the content of various bioactive compounds. This study aims to isolate, characterize the active compound from the stem bark of A. foveolata and test its activity as an antioxidant with the ABTS method, cytotoxic (MCF-7 cancer cells) with the MTT method, and antibacterial (bacterial strains ATCC and MDR) with the MIC. There are four isolated compounds obtained, namely (1) 17,24-epoxy-25-hydroxybaccharan-3-one, (2) β-stigmasterol glucoside, (3) Eichlerianic acid, and (4) 17,24-epoxy-25 -hydroxy-3- oxobaccharan-21-oic acid, which is a class of triterpenoid and steroid compounds. The best activity as an antioxidant was compound 3 (25.68 µg/mL); cytotoxic activity against MCF-7 cells namely compound 4 (94.59 µg/mL); antibacterial activity against ATCC strains: (1) P. aeruginosa namely compound 3 (29.4 µg/mL), (2) E. coli, (3) S. aureus, (4) B. subtilis for compounds 1, 2, and 4 have the same activity (62.5 µg/mL) while compound 3 was not active; MDR bacterial strains: (1) P. aeruginosa namely compound 4 (62.5 µg/mL), (2) E. coli namely compound 3 (62.5 µg/mL), (3) S. aureus namely compound 4 (62 .5 µg/mL), (4) B. subtilis namely compound 4 (62.5 µg/mL) and (5) K. pneumoniae namely compound 1 (125 µg/mL). [ABSTRACT FROM AUTHOR]

Gorgonians are a prominent part of coral reef fauna that changes in their abundance and diversity due to environmental changes. The present study was carried out to assess the relative abundance and diversity of gorgonian among islands with different anthropogenic stressors. The islands namely Burung, Geleang, Sambangan, and Seruni are protected areas of bird habitat, tourism area, mariculture activity, and empty, uninhabited islands, respectively. A rapid assessment of gorgonian genera was conducted by using the Roving Diver Visual Method on 4-11 March 2021. The Shannon diversity index, species richness, and evenness were computed to see the variation in the gorgonian community among islands. Results of the present study recorded 167 individuals representing 12 genera of gorgonian, which fall into 5 families namely, Ellisellidae, Plexauridae, Melithaeidae, Acanthogorgiidae and, Isididae. Of the four islands, abundance and species richness were not significantly different (F-value: 4.52; p: 0.09 >0.05). Statistically, there was also no significant difference among gorgonian genera (F-value: 1.01; p: 0.08 >0.05). However, the species diversity and abundance on the islands with low disturbance from various anthropogenic activities tended to increase. Monitoring is needed periodically to screen the condition of the gorgonian fauna. This study provides basic information for future monitoring due to the increasing eutrophication rate and tourism. [ABSTRACT FROM AUTHOR]

Nudibranchs are a prominent part of coral reef fauna that changes in their abundance and diversity due to environmental changes. The present study was carried out to assess the relative abundance and diversity of nudibranch among habitats receiving different degrees of sedimentation. A rapid assessment of nudibranch species was conducted by using the Roving Diver Visual Method on 20-27 August 2020. The sedimentation rate data were achieved by measure the number of sediments in traps that are placed in the sea bottom next to coral habitats. Results of the present study recorded 256 individuals representing 6 species of Nudibranchia, which fall into 4 families namely, Discodorididae, Chromodorididae, Polyceridae, and Phyllidiidae. Of the four sampling locations, abundance and species richness was no significantly different. The nudibranch Jorunna funebris species was the most abundant species. Statistically, there were no significant different on sedimentation rates among site locations. No correlations between levels of sedimentation rate and nudibranch abuncance were found either. Jepara coastal waters are still feasible to support the survival of nudibranch life. However, monitoring is needed periodically to screen the condition of the nudibranch fauna. This study provides basic information for future monitoring due to the increasing sedimentation rate and tourism [ABSTRACT FROM AUTHOR]

Tunicates (Ascidians, sea squirts) are marine protochordates, which live sedentary or sessile in colonial or solitary forms. These invertebrates have to protect themselves against predators and invaders. A most successful strategy, to not being eaten by predators and prevent pathogenic microorganisms to settle, is the usage of chemical molecules for defence. To accomplish this, tunicates take advantage of the specialized metabolites produced by the bacteria associated with them. Therefore, the microbiome of the tunicates can be regarded as a promising bioresource for bacterial strains producing compounds with antibacterial activity. The aim of this study was to test this hypothesis by (i) isolation of tunicate-associated bacteria, (ii) analysis of the antibacterial activities of these strains, and (iii) purification and structure elucidation of an active compound derived from this bioresource. In total, 435 bacterial strains were isolated and thereof 71 (16%) showed antibacterial activity against multidrug resistant (MDR) bacteria. Therefrom, the ethyl acetate crude extracts from liquid fermentations of 25 strains showed activity against MDR Extended-Spectrum Beta-Lactamase (MDR-ESBL) Escherichia coli, MDR Bacillus cereus, Micrococcus luteus, and Bacillus megaterium. Phenotypic analysis based on 16S rDNA sequencing revealed the active strains belonging to different genera and phyla, like Bacillus, Pantoea, Pseudoalteromonas, Salinicola, Streptomyces, Vibrio and Virgibacillus. To obtain first insights into the molecules responsible for the antibacterial activities observed, strain Pseudoalteromonas rubra TKJD 22 was selected for large-scale fermentation and the active compound was isolated. This allowed the purification and structure elucidation of isatin, a compound known for its strong biological effects, thereunder inhibition of Gram-positive and Gram-negative pathogens. [ABSTRACT FROM AUTHOR]

Citrus essential oils (EOs) have shown significant antibacterial activity. The present study was undertaken to evaluate the antibacterial activity of the peel oils of Citrus microcarpa and C. x amblycarpa against Escherichia coli. The minimum inhibition concentration (MIC) was determined by using the broth microdilution assay. The checkerboard method was used to identify synergistic effects of the EOs with tetracycline, while bacteriolysis was assessed by calculating the optical density of the bacterial supernatant, crystal violet assay was used to assess their antibiofilm. Ethidium bromide accumulation test was employed to assess efflux pump inhibition. Electron microscope analysis was performed to observe its morphological changes. The EOs of C. microcarpa and C. x amblycarpa were found to contain D-limonene major compound at 55.78% and 46.7%, respectively. Citrus microcarpa EOs exhibited moderate antibacterial against E. coli with a MIC value of 200 μg/mL. The combination of C. microcarpa oil (7.8 μg/mL) and tetracycline (62.5 μg/mL) exhibited a synergy with FICI of 0.5. This combination inhibited biofilm formation and disrupt bacterial cell membranes. Citrus microcarpa EOs blocked the efflux pumps in E. coli. Citrus microcarpa EOs demonstrated promising antibacterial activity, which can be further explored for the development of drugs to combat E. coli., (© The Author(s) 2023. Published by Oxford University Press on behalf of Applied Microbiology International.)

The aims of this work are to isolate bacterial symbionts from nudibranchs and subsequently to determine anti-Methicillin resistant Staphylococcus aureus (MRSA), cytotoxicity and anti-Herpes simplex virus type 1 (HSV-1) activities of bio compounds. A total of 15 species of nudibranchs were collected from Karimunjawa and five species from Bali, respectively. A total of 245 bacteria isolates were obtained. The anti-MRSA activity screening activity indicated two active bacteria. Ethyl acetate extracts from supernatants, indicating extracelullar compounds, showed an inhibition zone against MRSA at concentrations of 500-1,000 µg/ml. DNA sequence analysis showed that the strain KJB-07 from Phyllidia coelestis was closely related to Pseudoalteromonas rubra , whereas the strain NP31-01 isolated from Phyllidia varicosa was closely related to Virgibacillus salarius . The extract of Pseudoalteromonas rubra was cytotoxic to Vero cells at a concentration of 75 µg/ml. The extract of V. salarius presented no cytotoxicity at concentrations of 5-1,000 µg/ml. No anti HSV-1 was observed for both isolated bacteria. This is the first study describing research on anti-MRSA, cytotoxicity and anti HSV-1 activity of bacterial symbionts from the viscera of nudibranch. Compounds produced by Pseudoalteromonas rubra and V. salarius , had potential anti-MRSA activity. However, only extracts from Pseudoalteromonas rubra showed cytotoxic effects on Vero cells. Three compounds were identified by LC/MS after purification from culture supernatant., Competing Interests: The authors declare that they have no competing interests., (© 2020 Kristiana et al.)