Taxonomy and Antimicrobial Activity of Gliding Bacterium from Indonesian Mangroves

The discovery of new antibiotic is needed, due to the increasing antimicrobial resistance in nature. Therefore, this study aims to isolate gliding bacteria and to ascertain their antimicrobial activity against pathogenic microbes. This research was conducted by isolating gliding bacteria from mangrove sediment in Muara Angke, North Jakarta, Indonesia. All of the strains were identified by 16S rRNA genes sequencing and those selected strain was characterized using polyphasic approach. The performance of crude extracts against to ten pathogenic microorganisms were detected using serial dilution test in 96-well plates. Mangrove gliding bacteria isolates designated 313MSO and 314MSO were showed high homology to Ohtaekwangia kribbensis with 96.20% and 99.12% similarity, respectively. The polyphasic approach led to the conclusion that the strain 313MSO was a new species of the genus Ohtaekwangia. Twenty-three crude extracts were obtained from cultivating the strain in twenty-three different media. The most of them inhibited the growth of Staphylococcus aureus Newman with the minimum concentration of 33.33-66.67 µg/ml. Four compounds (Marinoquinolines A-D) were obtained from HPLC-MS analysis. Furthermore, the strain 313MSO is presently being studied for in-depth identification of additional unknown metabolites detected in the crude extracts

Isolation and Identification of a Myxobacterium Producing Myxovirescins, Myxalamides and Myxochromids from Intestinal Tract of earth Worm of Ghaemshahr County

Introduction: Myxobacteria are Gram-negative Deltaproteobacteria with rod-shaped vegetative cells, aerobic organotrophs that exhibit unique group behavior. Materials and Methods:The myxobacterial strain Mx18Zk was isolated from intestinal tract of earth worm of GhaemshahrCounty in Mazandaranprovince and the extraction of the fermented broth culture was prepared with organic solvent extraction method. Methanol extract tested for potential antimicrobial activity against11 various human pathogens. Finally the rest of methanol extract fractionated by HPLC and tested again against sensitive pathogens. Results: Strain Mx18Zk significantly inhibited growth of Escherichia coli, Staphylococcus aureus and Chromobacterium violaceum, therefore was used for further characterization. Analysis of morphological, biochemical, 16S rRNA gene sequence and phylogenetic tree indicated that this strain with 100 % homology belongs to the genus Corallococcus macrosporus . The methanol extract was subjected to HPLC fractionation against sensitive pathogens. The active extracts studied by LC-MS and its results compared by previously identified myxobacterial secondary metabolites deposited in Myxobase database of HZI. LC/MS analysis resulted in the identification of Myxochromids and unknown Myxovirescins, Myxalamides antibiotics in methanol extract of the strain Mx18Zk. Discussion and conclusion: On the basis of results, isolated strain was active against Escherichia coli, Staphylococcus aureus and Chromobacterium violaceum and100 % homology was belong to the genus Corallococcus macrosporus. LC/MS analysis resulted in the identification of Myxochromids and unknown Myxovirescins, Myxalamides antibiotics in methanol extract of the strain Mx18Zk

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

Non-Standard Errors

In statistics, samples are drawn from a population in a data-generating process (DGP). Standard errors measure the uncertainty in estimates of population parameters. In science, evidence is generated to test hypotheses in an evidence-generating process (EGP). We claim that EGP variation across researchers adds uncertainty: Non-standard errors (NSEs). We study NSEs by letting 164 teams test the same hypotheses on the same data. NSEs turn out to be sizable, but smaller for better reproducible or higher rated research. Adding peer-review stages reduces NSEs. We further find that this type of uncertainty is underestimated by participants

Special Issue: "Actinobacteria and Myxobacteria-Important Resources for Novel Antibiotics".

[[No abstract available

Special Issue: “Actinobacteria and Myxobacteria—Important Resources for Novel Antibiotics”

The history of our antibiotics is inseparably connected to microorganisms as producers [...

Actinobacteria from Arid and Desert Habitats: Diversity and Biological Activity.

The lack of new antibiotics in the pharmaceutical pipeline guides more and more researchers to leave the classical isolation procedures and to look in special niches and ecosystems. Bioprospecting of extremophilic Actinobacteria through mining untapped strains and avoiding resiolation of known biomolecules is among the most promising strategies for this purpose. With this approach, members of acidtolerant, alkalitolerant, psychrotolerant, thermotolerant, halotolerant and xerotolerant Actinobacteria have been obtained from respective habitats. Among these, little survey exists on the diversity of Actinobacteria in arid areas, which are often adapted to relatively high temperatures, salt concentrations, and radiation. Therefore, arid and desert habitats are special ecosystems which can be recruited for the isolation of uncommon Actinobacteria with new metabolic capability. At the time of this writing, members of Streptomyces, Micromonospora, Saccharothrix, Streptosporangium, Cellulomonas, Amycolatopsis, Geodermatophilus, Lechevalieria, Nocardia, and Actinomadura are reported from arid habitats. However, metagenomic data present dominant members of the communities in desiccating condition of areas with limited water availability that are not yet isolated. Furthermore, significant diverse types of polyketide synthase (PKS) and non-ribosomal peptide synthetase (NRPS) genes are detected in xerophilic and xerotolerant Actinobacteria and some bioactive compounds are reported from them. Rather than pharmaceutically active metabolites, molecules with protection activity against drying such as Ectoin and Hydroxyectoin with potential application in industry and agriculture have also been identified from xerophilic Actinobacteria. In addition, numerous biologically active small molecules are expected to be discovered from arid adapted Actinobacteria in the future. In the current survey, the diversity and biotechnological potential of Actinobacteria obtained from arid ecosystems, along with the recent work trend on Iranian arid soils, are reported

Diversity of Isolated from Date Palms Rhizosphere and Saline Environments: Isolation, Identification and Biological Activity Evaluation.

The diversity of cultural Actinobacteria in two types of Algerian Sahara environments, including saline environments and date palms rhizosphere, was investigated. In this study, a total of 40 strains of actinomycetes was isolated from different soil samples, using a rehydration and centrifugation method. Molecular identification, based on 16S rRNA gene sequence analysis, revealed that these isolates were affiliated to six clusters corresponding to eight genera, including Streptomyces, Nocardiopsis, Saccharopolyspora, Actinomadura, Actinocorallia, Micromonospora, Couchioplanes, and Planomonospora. A taxonomic analysis, based on the morphological, physiological, biochemical, and molecular investigation, of selected strains, which belong to the rare Actinobacteria, was undertaken. Four strains (CG3, A111, A93, and A79) were found to form distinct phyletic lines and represent new actinobacterial taxa. An assessment of antimicrobial proprieties of the 40 obtained actinomycetes strains, showed moderate to strong antimicrobial activities against fungi and bacteria. This study demonstrated the richness of Algerian Sahara with rare Actinobacteria, which can provide novel bioactive metabolites, to solving some of the most challenging problems of the day, such as multi-drug resistance