Peningkatan Ketahanan Tanaman Pisang Kepok Kuning terhadap Penyakit Darah melalui Variasi Somaklonal dan Simbiosis Endofitik

One of the obstacles that was encountered in the banana cultivation is blood disease. Blood diseases is caused by Ralstonia solanacearum that is subsequently revised to become blood disease bacteria (BDB). Until now the control of banana blood disease is very difficult. Control of banana blood disease with chemical injections and soil treatment is not effective. This study was aimed to obtain Kepok Kuning cultivar banana seedlings which was resistant towards blood disease obtained from in vitro selection by using BDB growing filtrate and induced resistance by inoculation of antagonistic endophytic bacteria.The observation of Kepok Kuning banana explants treated with various concentrations of BDB growing filtrate showed that the percentage of living explants decreased to 83.33% when the BDB growing filtrate concentration increased to 15%. Treatment of banana explants with BDB growing filtrate also affected the number of roots, shoots, and leaves. Treatment with a single antagonistic endophytic bacteria suppressed the intensity of banana blood disease to 0% in comparison with the mixture of antagonistic endophytic bacteria if Kepok Kuning banana explants were not treated with BDB growing filtrate. When Kepok Kuning banana explants were treated with BDB growing filtrate, the intensity of banana blood disease suppressed to 0% after the high concentration of BDB growing filtrate and the antagonistic endophytic bacteria mixture were applied. Salah satu kendala yang dihadapi dalam USAha budidaya pisang adalah adanya penyakit darah. Penyakit darah disebabkan oleh bakteri Ralstonia solanacearumyang selanjutnya direvisimenjadi bakteri darah pisang (Blood Disease Bacteria orBDB). Sampai saat ini pengendalian penyakit darah pisang sangatsukar dilakukan. Pengendalian penyakit darah dengan suntikan bahan kimia dan perlakuan tanah tidak efektif untuk diaplikasikan. Penelitian ini bertujuan untukmendapatkan bibit pisang kultivar Kepok Kuning yang tahan penyakit darah yang diperoleh dariseleksi in vitro dengan menggunakan filtrat pertumbuhan BDB dan induksi ketahanan melalui inokulasi jasad renik endofitik yang bersifat antagonis. Hasil pengamatan terhadap eksplan pisang Kepok Kuning yang diperlakukan dengan berbagai konsentrasi filtrat BDB menunjukkan bahwa pada eksplan yang diperlakukan dengan filtrat pertumbuhan BDB, persentase tumbuhnya akan berkurang hingga 83,33% jika konsentrasifiltrat pertumbuhanBDBmencapai 15%. Selain itu perlakuan planlet pisang dengan filtrat pertumbuhan BDB akan mempengaruhi jumlah akar, tunas, dan daun. Perlakuan dengan jasad renik endofitik antagonis secara tunggal mampu menekan intensitas penyakit darah hingga 0% jika dibandingkan dengan perlakuan campuran apabila sebelumnya eksplan pisang Kepok Kuning tidak diperlakukan dengan filtrat pertumbuhan BDB. Apabila sebelumnya planlet pisangKepokKuning diperlakukan dengan filtrat pertumbuhan BDB maka mampu menekan intensitas penyakit darah hingga 0% jika konsentrasi filtrat pertumbuhanBDBsemakin tinggi dan diperlakuan campuran jasad renik endofitik

Discovery of chromene compounds as inhibitors of PvdQ acylase of Pseudomonas aeruginosa

The acquisition of iron is a crucial mechanism for the survival of pathogenic bacteria such as Pseudomonas aeruginosa in eukaryotic hosts. The key iron chelator in this organism is the siderophore pyoverdine, which was shown to be crucial for iron homeostasis. Pyoverdine is a non-ribosomal peptide with several maturation steps in the cytoplasm and others in the periplasmatic space. A key enzyme for its maturation is the acylase PvdQ. The inhibition of PvdQ stops the maturation of pyoverdine causing a significant imbalance in the iron homeostasis and hence can negatively influence the survival of P. aeruginosa. In this work, we successfully synthesized chromene-derived inhibitory molecules targeting PvdQ in a low micromolar range. In silico modeling as well as kinetic evaluations of the inhibitors suggest a competitive inhibition of the PvdQ function. Further, we evaluated the inhibitor in vivo on P. aeruginosa cells and report a dose-dependent reduction of pyoverdine formation. The compound also showed a protecting effect in a Galleria mellonella infection model

Biotechnological Potential of Bacteria Isolated from the Sea Cucumber Holothuria leucospilota and Stichopus vastus from Lampung, Indonesia

In order to minimize re-discovery of already known anti-infective compounds, we focused our screening approach on understudied, almost untapped marine environments including marine invertebrates and their associated bacteria. Therefore, two sea cucumber species, Holothuria leucospilota and Stichopus vastus, were collected from Lampung (Indonesia), and 127 bacterial strains were identified by partial 16S rRNA-gene sequencing analysis and compared with the NCBI database. In addition, the overall bacterial diversity from tissue samples of the sea cucumbers H. leucospilota and S. vastus was analyzed using the cultivation-independent Illumina MiSEQ analysis. Selected bacterial isolates were grown to high densities and the extracted biomass was tested against a selection of bacteria and fungi as well as the hepatitis C virus (HCV). Identification of putative bioactive bacterial-derived compounds were performed by analyzing the accurate mass of the precursor/parent ions (MS1) as well as product/daughter ions (MS2) using high resolution mass spectrometry (HRMS) analysis of all active fractions. With this attempt we were able to identify 23 putatively known and two previously unidentified precursor ions. Moreover, through 16S rRNA-gene sequencing we were able to identify putatively novel bacterial species from the phyla Actinobacteria, Proteobacteria and also Firmicutes. Our findings suggest that sea cucumbers like H. leucospilota and S. vastus are promising sources for the isolation of novel bacterial species that produce compounds with potentially high biotechnological potential

Anti-Infective and Antiviral Activity of Valinomycin and Its Analogues from a Sea Cucumber-Associated Bacterium, Streptomyces sp. SV 21

The manuscript investigated the isolation, characterization and anti-infective potential of valinomycin (3), streptodepsipeptide P11A (2), streptodepsipeptide P11B (1), and one novel valinomycin analogue, streptodepsipeptide SV21 (4), which were all produced by the Gram-positive strain Streptomycescavourensis SV 21. Although the exact molecular weight and major molecular fragments were recently reported for compound 4, its structure elucidation was not based on compound isolation and spectroscopic techniques. We successfully isolated and elucidated the structure based on the MS2 fragmentation pathways as well as 1H and 13C NMR spectra and found that the previously reported structure of compound 4 differs from our analysis. Our findings showed the importance of isolation and structure elucidation of bacterial compounds in the era of fast omics technologies. The here performed anti-infective assays showed moderate to potent activity against fungi, multi drug resistant (MDR) bacteria and infectivity of the Hepatitis C Virus (HCV). While compounds 2, 3 and 4 revealed potent antiviral activity, the observed minor cytotoxicity needs further investigation. Furthermore, the here performed anti-infective assays disclosed that the symmetry of the valinomycin molecule is most important for its bioactivity, a fact that has not been reported so far

Induced Resistance Mechanism of Twisted Disease Suppression of Shallot by Bacillus Spp.

Plant Growth Promoting Rhizobacteria has been known for its ability to induce plant resistance on shallot against twisted disease. Its ability as a bioprotectant agent is estimated to be comparable to the efficacy of Trichoderma which is currently widely used as a biological control agent.. This study aims to determine the content of jasmonic acid, salicylic acid, peroxidase, and disease suppression in shallot by application of Bacillus velezensis B-27, Bacillus cereus RC76, and application with combination of both rhizobacteria. The application was carried out with tuber dipping for 30 minutes in each treatment with a bacterial density of 108 CFU mL-1. Application using Trichoderma was used as the comparison treatment, and the control plot was not given any treatment. Pathogen inoculation was carried out simultaneously as planting using Fusarium acutatum with a spore density of 106 CFU mL-1. The jasmonic and salicylic acids content was measured using the High-Performance Liquid Chromatography method, and the peroxidase content was determined using the spectrophotometric method. Disease suppression was measured at 10-day intervals. The results showed that treatment with Bacillus cereus RC76 increased jasmonic and salicylic acid levels, while application with Bacillus velezensis B-27 showed the highest level of peroxidase. Treatments with Bacillus spp. were able to suppress twisted disease by 72.2% to 100%. This study demonstrated that application Bacillus spp. suppressed twisted disease on shallot and increased the jasmonic and salicylic acid content as induced resistance mechanism against pathogens

Anti-Infective and Antiviral Activity of Valinomycin and Its Analogues from a Sea Cucumber-Associated Bacterium, Streptomyces sp. SV 21

The manuscript investigated the isolation, characterization and anti-infective potential of valinomycin (3), streptodepsipeptide P11A (2), streptodepsipeptide P11B (1), and one novel valinomycin analogue, streptodepsipeptide SV21 (4), which were all produced by the Gram-positive strain Streptomycescavourensis SV 21. Although the exact molecular weight and major molecular fragments were recently reported for compound 4, its structure elucidation was not based on compound isolation and spectroscopic techniques. We successfully isolated and elucidated the structure based on the MS2 fragmentation pathways as well as 1H and 13C NMR spectra and found that the previously reported structure of compound 4 differs from our analysis. Our findings showed the importance of isolation and structure elucidation of bacterial compounds in the era of fast omics technologies. The here performed anti-infective assays showed moderate to potent activity against fungi, multi drug resistant (MDR) bacteria and infectivity of the Hepatitis C Virus (HCV). While compounds 2, 3 and 4 revealed potent antiviral activity, the observed minor cytotoxicity needs further investigation. Furthermore, the here performed anti-infective assays disclosed that the symmetry of the valinomycin molecule is most important for its bioactivity, a fact that has not been reported so far

Discovery of chromene compounds as inhibitors of PvdQ acylase of Pseudomonas aeruginosa

The acquisition of iron is a crucial mechanism for the survival of pathogenic bacteria such as Pseudomonas aeruginosa in eukaryotic hosts. The key iron chelator in this organism is the siderophore pyoverdine, which was shown to be crucial for iron homeostasis. Pyoverdine is a non-ribosomal peptide with several maturation steps in the cytoplasm and others in the periplasmatic space. A key enzyme for its maturation is the acylase PvdQ. The inhibition of PvdQ stops the maturation of pyoverdine causing a significant imbalance in the iron homeostasis and hence can negatively influence the survival of P. aeruginosa. In this work, we successfully synthesized chromene-derived inhibitory molecules targeting PvdQ in a low micromolar range. In silico modeling as well as kinetic evaluations of the inhibitors suggest a competitive inhibition of the PvdQ function. Further, we evaluated the inhibitor in vivo on P. aeruginosa cells and report a dose-dependent reduction of pyoverdine formation. The compound also showed a protecting effect in a Galleria mellonella infection model

Biotechnological Potential of Bacteria Isolated from the Sea Cucumber and from Lampung, Indonesia.

In order to minimize re-discovery of already known anti-infective compounds, we focused our screening approach on understudied, almost untapped marine environments including marine invertebrates and their associated bacteria. Therefore, two sea cucumber species, Holothuria leucospilota and Stichopus vastus, were collected from Lampung (Indonesia), and 127 bacterial strains were identified by partial 16S rRNA-gene sequencing analysis and compared with the NCBI database. In addition, the overall bacterial diversity from tissue samples of the sea cucumbers H. leucospilota and S. vastus was analyzed using the cultivation-independent Illumina MiSEQ analysis. Selected bacterial isolates were grown to high densities and the extracted biomass was tested against a selection of bacteria and fungi as well as the hepatitis C virus (HCV). Identification of putative bioactive bacterial-derived compounds were performed by analyzing the accurate mass of the precursor/parent ions (MS1) as well as product/daughter ions (MS2) using high resolution mass spectrometry (HRMS) analysis of all active fractions. With this attempt we were able to identify 23 putatively known and two previously unidentified precursor ions. Moreover, through 16S rRNA-gene sequencing we were able to identify putatively novel bacterial species from the phyla Actinobacteria, Proteobacteria and also Firmicutes. Our findings suggest that sea cucumbers like H. leucospilota and S. vastus are promising sources for the isolation of novel bacterial species that produce compounds with potentially high biotechnological potential