Streptomyces Griseus Research Articles

SECONDARY METABOLITES OF ANTAGONISTIC BACTERIAL STRAIN Streptomyces griseus KD1 EXERT ANTIBACTERIAL AND ANTICANCER ACTIVITY AGAINST BREAST CANCER MCF-7 CELLS

Numerous types of bioactive compounds are produced in large quantities by marine microorganisms. In this work, the antagonistic marine bacterium strain Streptomyces griseus was isolated from soil samples taken from the beach into mangrove estuary region, and its unprocessed secondary metabolites were assessed for their potential antibacterial and anticancer properties. Using 16S rRNA sequencing study, the strong antagonistic bacterial isolate S. griseus was discovered. After being isolated from strain S. griseus using centrifugation and ethanol, the secondary metabolites were tested for antibacterial efficacy against bacterial pathogens of the respiratory tract using the agar well diffusion technique. This investigation indicated that the metabolic extract of the KD1 successfully reduced the development of clinical bacterial infections. Also confirmed concentration-dependent cytotoxicity against MCF-7 breast cancer cells. When metabolic extract of the KD1 was administered, it effectively inhibited the growth of MCF-7 cell colonies, increased lipid peroxidation, and lowered antioxidant activity. The findings demonstrated that the KD1 metabolic extract had potent antibacterial and anticancer activities. Therefore, with further clinical testing, it is possible to develop effective antibiotics and anticancer medications for breast cancer using the secondary metabolites of the S. griseus KD1 strain.

Sol-Gel Synthesis of ZnO Nanoparticles Using Different Chitosan Sources: Effects on Antibacterial Activity and Photocatalytic Degradation of AZO Dye

Chitosan was used in the sol-gel synthesis of zinc oxide nanoparticles (ZnO NPs) as a capping agent in order to control the size, morphology, optical bandgap, photocatalytic efficiency, and antimicrobial activity. Different chitosan sources were used for the sol-gel synthesis of ZnO NPs, namely chitosan of shrimp shells, crab shells, and Streptomyces griseus bacteria. The photocatalytic efficiency was studied by using the methylene blue (MB) photodegradation test, and the antibacterial activity of the different types of ZnO NPs was investigated by the agar well diffusion technique. The particle size of ZnO NPs varied between 20 and 80 nm, and the band gap energy ranged between 2.7 and 3.2 eV. Due to the different chitosan sources, the ZnO NPs showed different antibacterial activity against Listeria innocua, Bacillus Subtiliis, Staphylococcus Aureus, Salmonella Typhimurium and Pseudomonas Aeruginosa. The ZnO NPs with lower band gap values showed better antibacterial results compared to ZnO NPs with higher band gap values. The MB dye removal of ZnO (shrimp shells), ZnO (crab shells), and ZnO (Streptomyces griseus) reached 60%, 56%, and 44%, respectively, at a contact time of 60 min, a low initial MB dye concentration of 6 × 10−5 M, a solution temperature of 25 °C, and a pH = 7.

Rootstock Priming with Shikimic Acid and Streptomyces griseus for Growth, Productivity, Physio-Biochemical, and Anatomical Characterisation of Tomato Grown under Cold Stress

With this research, we aimed to determine the impact of grafting and rootstock seed treated with Streptomyces griseus (MT210913) (S. griseus) or shikimic acid (SA) at a 60 ppm concentration on tomato (Solanum lycopersicum L.) production grown under low-temperature conditions. Two open-field trials were performed during both winter seasons of 2020 and 2021 at the Experimental Farm, Faculty of Agriculture, Cairo University, Giza, Egypt. A tomato cultivar (Peto 86) was used as a scion and two tomato phenotypes were employed as rootstocks (Solanum cheesmaniae L. (line LA 524) and GS hybrid), as well as self-grafted as a control. Effects of sub-optimal temperature on vegetative growth, yield, and fruit quality were tested. The results indicate that, under cold stress, rootstock seed priming, especially with S. griseus, enhanced plant growth, total yield, and fruit quality properties. GS hybrid rootstock was more effective than that of S. cheesmaniae rootstock in terms of mitigating the negative effect of cold stress. GS hybrid, inoculated with S. griseus, increased the total yield per plant by 10.5% and 5.7% in the first and second seasons, respectively. Higher levels of GA3 and mineral content were noticed in leaves that were grafted and treated with S. griseus compared to the control treatment. Additionally, the great enhancing effects of all anatomical features of tomato plants were recorded with GS hybrid rootstock, inoculated by S. griseus. These results prove that grafting on GS hybrid rootstock treated with S. griseus is a potential choice to alleviate the cold stress of commercial tomato varieties.

Nghiên cứu ứng dụng chủng xạ khuẩn Streptomyces griseus VTCC 41724 trong phòng chống bệnh thối gốc lúa do vi khuẩn Dickeya zeae

Foot rot disease caused by Dickeya zeae in rice has been recently concerned in Vietnam, though there has not been a specific prevention and treatment measure. Streptomyces griseus strain VTCC 41724 has been previously reported for the antagonistic properties against Dickeya zeae and other plant pathogenic bacteria, it is therefore investigated for the capability of controlling this disease. Thus, the strain is selected for further studies aiming to application in organic rice cultivation. In this study, the appropriate culture conditions for strain VTCC 41724 to grow and release bioactive substances inhibiting D. zeae were determined, i.e. 2M medium, 5 days, 5% inoculum, and shaking at 160 rpm at 30C. A microbial formulation SGB was created from biomass of strain VTCC 41724 (7.1  108 CFU/g) and tested for its effectiveness in controlling the foot rot disease caused by Dickeya zeae under net house conditions. The experiment was carried out on Bac Thom No.7 rice variety, applied the SGB formulation in the soil before the seed and during the disease symptoms, has resulted in a protective efficiency as high as 73.56%. In addition, strain Streptomyces griseus VTCC 41724 also showed the antagonistic activity against harmful fungi including Phytophthora capsici, Alternaria sp., Colletotrichum gloeosporioides and Fusarium sp. This preliminary results showed the potential application of actinomycetes in biological control of foot rot caused by D. zeae, and other microbially mediated plant diseases.

Elicitation of Innate Immunity by a Bacterial Volatile 2-Nonanone at Levels below Detection Limit in Tomato Rhizosphere.

Bacterial volatile compounds (BVCs) exert beneficial effects on plant protection both directly and indirectly. Although BVCs have been detected in vitro, their detection in situ remains challenging. The purpose of this study was to investigate the possibility of BVCs detection under in situ condition and estimate the potentials of in situ BVC to plants at below detection limit. We developed a method for detecting BVCs released by the soil bacteria Bacillus velezensis strain GB03 and Streptomyces griseus strain S4-7 in situ using solid-phase microextraction coupled with gas chromatography-mass spectrometry (SPME-GC-MS). Additionally, we evaluated the BVC detection limit in the rhizosphere and induction of systemic immune response in tomato plants grown in the greenhouse. Two signature BVCs, 2-nonanone and caryolan-1-ol, of GB03 and S4-7 respectively were successfully detected using the soil-vial system. However, these BVCs could not be detected in the rhizosphere pretreated with strains GB03 and S4-7. The detection limit of 2-nonanone in the tomato rhizosphere was 1 µM. Unexpectedly, drench application of 2-nonanone at 10 nM concentration, which is below its detection limit, protected tomato seedlings against Pseudomonas syringae pv. tomato. Our finding highlights that BVCs, including 2-nonanone, released by a soil bacterium are functional even when present at a concentration below the detection limit of SPME-GC-MS.

Enhanced catalytic efficiency and substrate specificity of Streptomyces griseus trypsin by evolution-guided mutagenesis

Streptomyces griseus trypsin (SGT) is a bacteria-sourced trypsin that could be potentially applied to industrial insulin productions. However, SGT produced by microbial hosts displayed low catalytic efficiency and undesired preference to lysine residue. In this study, by engineering the α signal peptide in Pichia pastoris, we increased the SGT amidase activity to 67.91 U mL−1 in shake flask cultures. Afterwards, we engineered SGT by evolution-guided mutagenesis and obtained three variants A45S, V177I and E180M with increased catalytic efficiencies. On this basis, we performed iterative combinatorial mutagenesis and constructed a mutant A45S/V177I/E180M which the amidase activity reached 98 U mL−1 in shake flasks and 2506 U mL−1 in 3-L fed-batch cultures. Moreover, single mutation T190 to S190 increased the substrate catalytic preference of R to K and the R/K value was improved to 7.5, which was 2 times better than the animal-sourced trypsin.

Structures, Mechanism, and Functional Relevance of Filament Formation by SgrAI

SgrAI is a type II Restriction endonuclease (REases) enzyme from the bacterium Streptomyces griseus. It has been proposed that SgrAI protects the host DNA from off‐target cleavage activity, through a new regulation mechanism via filamentation. Binding of SgrAI to invading phage DNA activates the enzyme leading to DNA sequence specificity expansion from 3 recognition sites to 17 and increased DNA cleavage rate. Like other types of II REases, SgrAI cleaves DNA in a Mg2+ dependent manner. But unlike other REases that form homodimers and cleave near their 4‐6bp recognition sequence, SgrAI forms a filament when in its active form, and a dimer when found in its inactive form. In its active form, SgrAI exhibits an increased rate of DNA cleavage 200 to 1000‐fold faster. The mechanistic underlying these events remain unclear.We have been investigating the details of SgrAI’s structure and cleavage activity on its secondary site DNA sequences to complete our understanding of SgrAI’s kinetic pathway and filament formation. In our recent discoveries, we described two new structures of the SgrAI enzyme, one is the Cryo‐EM structure of the filamentous form of SgrAI bound to intact primary site DNA, and the other one is a high‐resolution x‐ray crystal structure of apo SgrAI. These structures help us to understand important conformational changes that could be contributed to the catalytic mechanism of this enzyme.

Promiscuous Catalytic Activity of a Binuclear Metallohydrolase: Peptide and Phosphoester Hydrolyses.

In this study, chemical promiscuity of a binuclear metallohydrolase Streptomyces griseus aminopeptidase (SgAP) has been investigated using DFT calculations. SgAP catalyzes two diverse reactions, peptide and phosphoester hydrolyses, using its binuclear (Zn-Zn) core. On the basis of the experimental information, mechanisms of these reactions have been investigated utilizing leucine p-nitro aniline (Leu-pNA) and bis(4-nitrophenyl) phosphate (BNPP) as the substrates. The computed barriers of 16.5 and 16.8 kcal/mol for the most plausible mechanisms proposed by the DFT calculations are in good agreement with the measured values of 13.9 and 18.3 kcal/mol for the Leu-pNA and BNPP hydrolyses, respectively. The former was found to occur through the transfer of two protons, while the latter with only one proton transfer. They are in line with the experimental observations. The cleavage of the peptide bond was the rate-determining process for the Leu-pNA hydrolysis. However, the creation of the nucleophile and its attack on the electrophile phosphorus atom was the rate-determining step for the BNPP hydrolysis. These calculations showed that the chemical nature of the substrate and its binding mode influence the nucleophilicity of the metal bound hydroxyl nucleophile. Additionally, the nucleophilicity was found to be critical for the Leu-pNA hydrolysis, whereas double Lewis acid activation was needed for the BNPP hydrolysis. That could be one of the reasons why peptide hydrolysis can be catalyzed by both mononuclear and binuclear metal cofactors containing hydrolases, while phosphoester hydrolysis is almost exclusively by binuclear metallohydrolases. These results will be helpful in the development of versatile catalysts for chemically distinct hydrolytic reactions.

Evaluation of Soil Streptomyces Isolates from North-Western Ethiopia as Potential Inhibitors against Spoilage and Foodborne Bacterial Pathogens

The outbreak and spread of foodborne diseases is a serious concern for global healthcare and security. Finding novel antimicrobial agents with diverse mechanisms of action against the current spoilage and foodborne bacterial pathogens is a central strategy to overcome the problems of antibiotic resistance. Soil actinomycetes are the major antimicrobial producers with great biopreservative and medical value. This study was aimed at isolating Streptomyces from soil samples of northwestern Ethiopia against spoilage and foodborne bacterial pathogens. Thirty-six soil samples were collected at a depth of 5–10 cm in the rhizosphere and agricultural soils of soybean. A total of 118 actinomycete strains were isolated and screened primarily using the perpendicular streak plate method against 3 Gram-positive and 3 Gram-negative bacterial strains. Out of 118 isolates, 36/118 (30.50%) were active against at least two of the tested bacteria, of which 8 isolates were selected for their wide-spectrum antibacterial activities. During the disc diffusion assay, the eight in vitro ethyl acetate extract antibacterial activities range from 7 to 24 mm. The minimum inhibitory concentration and minimum bactericidal concentration values range from 0.10 to 0.25 μg/mL and 0.15 to 0.40 μg/mL, respectively. Following the morphological, physiological, biochemical, and molecular characteristics, eight potent isolates were identified as follows: Streptomyces fasciculus, Streptomyces roseochromogenes, Streptomyces ruber, Streptomyces glaucus, Streptomyces griseus, Streptomyces cellulosae, Streptomyces griseoflavus, and Streptomyces xanthophaeus. After the treatment of potent Streptomyces cell-free culture supernatant with proteinase K, papain, α-amylase, and lysozyme enzymes, their antagonistic effects were also observed. Most Streptomyces cell-free culture supernatant antibacterial activity was highly resistant to heat, acidity, organic solvents, and additives. Thus, the results of this investigation revealed that soil actinomycetes could be a valuable source for novel antibacterial agents applicable in food biopreservation and the treatment of spoilage and foodborne bacterial pathogens.

System-Level Analysis of Transcriptional and Translational Regulatory Elements in Streptomyces griseus.

Bacteria belonging to Streptomyces have the ability to produce a wide range of secondary metabolites through a shift from primary to secondary metabolism regulated by complex networks activated after vegetative growth terminates. Despite considerable effort to understand the regulatory elements governing gene expression related to primary and secondary metabolism in Streptomyces, system-level information remains limited. In this study, we integrated four multi-omics datasets from Streptomyces griseus NBRC 13350: RNA-seq, ribosome profiling, dRNA-seq, and Term-Seq, to analyze the regulatory elements of transcription and translation of differentially expressed genes during cell growth. With the functional enrichment of gene expression in different growth phases, one sigma factor regulon and four transcription factor regulons governing differential gene transcription patterns were found. In addition, the regulatory elements of transcription termination and post-transcriptional processing at transcript 3′-end positions were elucidated, including their conserved motifs, stem-loop RNA structures, and non-terminal locations within the polycistronic operons, and the potential regulatory elements of translation initiation and elongation such as 5′-UTR length, RNA structures at ribosome-bound sites, and codon usage were investigated. This comprehensive genetic information provides a foundational genetic resource for strain engineering to enhance secondary metabolite production in Streptomyces.

Enhanced production of \u03b3-amino acid 3-amino-4-hydroxybenzoic acid by recombinant Corynebacterium glutamicum under oxygen limitation

BackgroundBio-based aromatic compounds are of great interest to the industry, as commercial production of aromatic compounds depends exclusively on the unsustainable use of fossil resources or extraction from plant resources. γ-amino acid 3-amino-4-hydroxybenzoic acid (3,4-AHBA) serves as a precursor for thermostable bioplastics.ResultsUnder aerobic conditions, a recombinant Corynebacterium glutamicum strain KT01 expressing griH and griI genes derived from Streptomyces griseus produced 3,4-AHBA with large amounts of amino acids as by-products. The specific productivity of 3,4-AHBA increased with decreasing levels of dissolved oxygen (DO) and was eightfold higher under oxygen limitation (DO = 0 ppm) than under aerobic conditions (DO ≥ 2.6 ppm). Metabolic profiles during 3,4-AHBA production were compared at three different DO levels (0, 2.6, and 5.3 ppm) using the DO-stat method. Results of the metabolome analysis revealed metabolic shifts in both the central metabolic pathway and amino acid metabolism at a DO of < 33% saturated oxygen. Based on this metabolome analysis, metabolic pathways were rationally designed for oxygen limitation. An ldh deletion mutant, with the loss of lactate dehydrogenase, exhibited 3.7-fold higher specific productivity of 3,4-AHBA at DO = 0 ppm as compared to the parent strain KT01 and produced 5.6 g/L 3,4-AHBA in a glucose fed-batch culture.ConclusionsOur results revealed changes in the metabolic state in response to DO concentration and provided insights into oxygen supply during fermentation and the rational design of metabolic pathways for improved production of related amino acids and their derivatives.Graphical

Structure, dynamics, and function of SrnR, a transcription factor for nickel-dependent gene expression.

Streptomyces griseus, a bacterium producing antibacterial drugs and featuring possible application in phytoremediation, expresses two metal-dependent superoxide dismutase (SOD) enzymes, containing either Fe(II) or Ni(II) in their active site. In particular, the alternative expression of the two proteins occurs in a metal-dependent mode, with the Fe(II)-enzyme gene (sodF) repressed at high intracellular Ni(II) concentrations by a two-component system (TCS). This complex involves two proteins, namely SgSrnR and SgSrnQ, which represent the transcriptional regulator and the Ni(II) sensor of the system, respectively. SgSrnR belongs to the ArsR/SmtB family of metal-dependent transcription factors; in the apo-form and in the absence of SgSrnQ, it can bind the DNA operator of sodF, upregulating gene transcription. According to a recently proposed hypothesis, Ni(II) binding to SgSrnQ would promote its interaction with SgSrnR, causing the release of the complex from DNA and the consequent downregulation of the sodF expression. SgSrnQ is predicted to be highly disordered, thus the understanding, at the molecular level, of how the SgSrnR/SgSrnQ TCS specifically responds to Ni(II) requires the knowledge of the structural, dynamic, and functional features of SgSrnR. These were investigated synergistically in this work using X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, atomistic molecular dynamics calculations, isothermal titration calorimetry, and in silico molecular docking. The results reveal that the homodimeric apo-SgSrnR binds to its operator in a two-step process that involves the more rigid globular portion of the protein and leaves its largely disordered regions available to possibly interact with the disordered SgSrnQ in a Ni-dependent process.

Delving into defence: identifying the Pseudomonas protegens Pf-5 gene suite involved in defence against secreted products of fungal, oomycete and bacterial rhizosphere competitors.

Competitive behaviours of plant growth promoting rhizobacteria (PGPR) are integral to their ability to colonize and persist on plant roots and outcompete phytopathogenic fungi, oomycetes and bacteria. PGPR engage in a range of antagonistic behaviours that have been studied in detail, such as the production and secretion of compounds inhibitory to other microbes. In contrast, their defensive activities that enable them to tolerate exposure to inhibitory compounds produced by their neighbours are less well understood. In this study, the genes involved in the Pseudomonas protegens Pf-5 response to metabolites from eight diverse rhizosphere competitor organisms, Fusarium oxysporum, Rhizoctonia solani, Gaeumannomyces graminis var. tritici, Pythium spinosum, Bacillus subtilis QST713, Pseudomonas sp. Q2-87, Streptomyces griseus and Streptomyces bikiniensis subspecies bikiniensi, were examined. Proximity induced excreted metabolite responses were confirmed for Pf-5 with all partner organisms through HPLC before culturing a dense Pf-5 transposon mutant library adjacent to each of these microbes. This was followed by transposon-directed insertion site sequencing (TraDIS), which identified genes that influence Pf-5 fitness during these competitive interactions. A set of 148 genes was identified that were associated with increased fitness during competition, including cell surface modification, electron transport, nucleotide metabolism, as well as regulatory genes. In addition, 51 genes were identified for which loss of function resulted in fitness gains during competition. These included genes involved in flagella biosynthesis and cell division. Considerable overlap was observed in the set of genes observed to provide a fitness benefit during competition with all eight test organisms, indicating commonalities in the competitive response to phylogenetically diverse micro-organisms and providing new insight into competitive processes likely to take place in the rhizosphere.

Influence of environmental conditions on plants in different climatic zones

Due to global shifts in climate, studies in contrasting conditions of two natural and climatic zones are of particular interest: (1) subzone of mixed and broad-leaved forests, (2) south-steppe subzone. In the period 2019-2020, 308 plant species from 56 families were surveyed. Phytopathogens damage plants, and therefore increase the loss of quality of plant materials. The frequency of occurrence of mycoses in autumn is 2-14 times higher than in spring-summer observations. The activity of phytopathogenic fungi of the genera of Fusarium (the causative agent of fusarium), Puccinia (rust), Phoma (phomosis), Rhizoctonia (scab), Verticillium (tracheomycotic or vascular wilting) increases. Differences in dominant micromycetes from the point of view of geography were determined: zone 1 (forest) - Alternaria spp., Chaetomium spp., Fusarium spp., F. avenaceum (Fr.) Sacc., (Mart.) Sacc., Heterosporium iridis (Fautrey & Roum.) JE Jacques, Phoma spp., Stemphylium spp., Verticillium spp.; zone 2 (steppe) – Alternaria spp., Botrytis spp., Cladosporium spp., Fusarium avenaceum, Fusarium spp., Peronospora spp., Phoma spp., Pullularia spp., Septoria spp. Screening of pesticides (biological fungicides) showed the effectiveness of preparations based on Pseudomonas fluorescens, Bacillus subtilis or Streptomyces griseus in limiting the growth of the mycelium of phytopathogenic fungi.

ISOLATION AND IDENTIFICATION OF CHOLESTEROL OXIDASE PRODUCING ACTINOMYCETES FROM EGYPTIAN SOIL FOR A LARGE SCALE FERMENTATION IN SUBMERGED CULTURES

Isolation and identification of new microbial isolates capable of producing cholesterol oxidase enzyme (CHO) is of great potential in the field of biotechnology of industrial enzymes. Four producing strains of actinomycetes were isolated from Egyptian soils demonstrated high activity in cholesterol degradation compared to the other isolates. Based on different standard morphological, biochemical as well as molecular techniques using 16S rRNA sequencing, these actinomycetes were identified as Streptomyces sp. strain NHIA_CH3 MK680299, Streptomyces sp. strain NHIA_CH5 MK680300 , Streptomyces griseus strain NHIA_CH6 MK680301 and Streptomyces drozdowiczii strain NHIA_CH10 MK680302. In order to optimize the CHO enzyme activity, different fermentation media were tested in submerged cultures at shake flask level. Maximum activity (23.7 U/mL) was observed in culture of Streptomyces sp. strain NHIA_CH5 which was scaled up to the 5L volume of the stirred tank bioreactor. Results of the batch fermentation showed an earlier production of CHO enzyme with 4% increase in activity compared to that obtained from shake flask cultures indicated that Streptomyces sp. strain NHIA_CH5 could be a potential source of CHO enzyme for commercial purpose.

Synthesis of composite derived from carbon nanoparticles and digallate stabilized silver nanoparticles for their bactericidal efficacy

Current study reports synthesis, characterisation and antibacterial efficacy of nanocomposites derived from carbon nanoparticles (CNP) and silver nanoparticles (AgNPs). The reaction was performed at ambient temperature and digallate (dimer of gallic acid) was used as an active stabilizing and reducing agent. The CNP-AgNP nanocomposite (CNP-AgNC) was characterised by UV–vis, HR-TEM, SEM, Zeta potential and DLS. These composites were examined for their antibacterial efficacy using the strains Staphylococcus aureus, Bacillus subtilis, Streptomyces griseus and Escherichia coli. Our study reveals that this proposed nanocomposite is an efficient antibacterial agent.

Isolation of antibiotics producing bacteria from marine soil and comparative analysis of same with commercially available drugs

The isolation of antibiotic producing bacteria from marine soil and comparative analysis of same with ciprofloxacin and amoxicillin against staphylococcus aureus and Escherichia coli was carried out in a Microbiology Laboratory of Chukwuemeka Odumegwu Ojukwu University, Uli. This was done to isolate antibiotic producing bacteria and compare same with existing commercially available antibiotics with a view to using marine soil in the treatment of common bacterial infections. Soil samples were collected from Bonny Island Sea, Port Harcourt. One gram of mixed soil sample was serially diluted and spread-plated on nutrient agar plates. The representative isolates obtained were sub-cultured to get a pure culture. Morphological, biochemical, physiological characteristics of the bacteria were analyzed. Agar well diffusion was carried out. One isolate had a substantial antibacterial activity with 3.5mm zone of inhibition against two test bacteria used in the preliminary screening. The isolate was marked as Streptomyces (STR I) and was identified as Streptomyces griseus while other isolates did not show any antibacterial activity. Ciprofloxacin showed the highest antibacterial activity to both Staphylococcus aureus and Escherichia coli of 3.7mm and 4.0mm respectively while Amoxicillin showed antibacterial activity of 3.5mm and 2.7mm respectively. This reveals that antibiotic producing bacteria from marine soil are also effective in antimicrobial activity and could be used for antimicrobial chemotherapy.

Streptomyces griseus KJ623766: A Natural Producer of Two Anthracycline Cytotoxic Metabolites β- and γ-Rhodomycinone.

Background: This study aimed to produce, purify, structurally elucidate, and explore the biological activities of metabolites produced by Streptomyces (S.) griseus isolate KJ623766, a recovered soil bacterium previously screened in our lab that showed promising cytotoxic activities against various cancer cell lines. Methods: Production of cytotoxic metabolites from S. griseus isolate KJ623766 was carried out in a 14L laboratory fermenter under specified optimum conditions. Using a 3-(4,5-dimethylthazol-2-yl)-2,5-diphenyl tetrazolium-bromide assay, the cytotoxic activity of the ethyl acetate extract against Caco2 and Hela cancer cell lines was determined. Bioassay-guided fractionation of the ethyl acetate extract using different chromatographic techniques was used for cytotoxic metabolite purification. Chemical structures of the purified metabolites were identified using mass, 1D, and 2D NMR spectroscopic analysis. Results: Bioassay-guided fractionation of the ethyl acetate extract led to the purification of two cytotoxic metabolites, R1 and R2, of reproducible amounts of 5 and 1.5 mg/L, respectively. The structures of R1 and R2 metabolites were identified as β- and γ-rhodomycinone with CD50 of 6.3, 9.45, 64.8 and 9.11, 9.35, 67.3 µg/mL against Caco2, Hela and Vero cell lines, respectively. Values were comparable to those of the positive control doxorubicin. Conclusions: This is the first report about the production of β- and γ-rhodomycinone, two important scaffolds for synthesis of anticancer drugs, from S. griseus.

Ragam Jenis Streptomyces Sp pada Rizosfer Tanaman Suku Liliacea di Kawasan Desa Sumber Bening

Streptomyces is a gram-positive bacterium of the Actinomycetes group. These bacteria are known as beneficial bacteria in human life, both for humans themselves and for plants. The secondary metabolites of Streptomyces can be used as an antibacterial, antifungal, insecticide for plants and as an anthelmintic for humans. This research is motivated by the absence of research that discusses Streptomyces sp in the plant rhizosphere of the Liliaceae tribe in the Sumber bening village area. So that researchers are interested in doing this research. This study aims to determine the diversity of Streptomyces sp in the soil rhizosphere of Liliaceae plants in the Sumber Bening area. This study uses the Research and Development method. The study was conducted by isolating Streptomyces sp from the Rizosphere of three plants of the Liliaceae tribe, namely shallots (Allium cepa), Onions (Allium fistulosum) and Kucai (Allium schoenoprasum L) using YPGA medium (Yeast Peptone Dextrose Agar) and pouring down isolation techniques. After the isolates are obtained, the isolates will be purified by means of a scratch technique. Pure Streptomyces sp isolates were identified based on their morphological characteristics both microscopically and macroscopically. The results showed that there were 11 species of Streptomyces sp found in three Liliaceae plant rhizosphere with 6 species found in the onion rhizosphere, 3 species found in the leek rhizosphere and 2 species found in the rhizosphere of chives. There are Streptomyces griseourubiginosus, Streptomyces albovinaceus, Streptomyces griseus, Streptomyces albohelvatus, Streptomyces viridaris, Streptomyces hirsutus, Streptomyces nigrescens, Streptomyces herbaricolor, Streptomyces aureofaciens, Streptomyces nigrogriceolus,dan Streptomyces albolongus.

SPECTRAL EVALUATION AND ANTIMICROBIAL ACTIVITY OF SYNTHESIZED 4H-1,4-BENZOTHIAZINES

Objective: 4H-1,4-Benzothiazines constitute an important class of heterocycles containing 1,4-thiazine ring fused to benzene ring. They are extensively used as tranquilizer, antispasmodic, central nervous system depressant, antiulcer, antibacterial, antifungal, antioxidant, anticancer agents, fungicides, etc. Therefore, these observations prompted us to synthesize substituted 4H-1,4-benzothiazines and investigate their antimicrobial activity against selected bacterial and fungal strains.&#x0D; Methods: In the present research work, 2-Amino-3,5,6-trichlorobenzenethiol condensed with β-diketones/β-ketoesters in the presence of dimethyl sulfoxide followed by oxidative cyclisation leading to the formation of 4H-1,4-benzothiazines. The spectral investigation confirmed the synthesis of these bioactive compounds. All synthesized compounds were screened for their antimicrobial activity (antibacterial and antifungal) using agar well diffusion method.&#x0D; Results: The minimum inhibitory concentration values of synthesized compounds gave excellent results against bacterial as well as fungal strains (Escherichia coli [Gram negative] MTCC 2939, 58–158 μg/mL, Bacillus subtilis [Gram positive] MTCC 441, 41–124 μg/mL, Streptomyces griseus [Gram negative] MTCC 1998, 85–128 μg/mL, Fusarium oxysporum MTCC 1755, 142–151 μg/mL, Aspergillus niger MTCC 281, 59–78 μg/mL, and Rhizopus stolonifer MTCC 2591, 85–118 μg/mL).&#x0D; Conclusion: Synthesized substituted benzothiazines have potential to be used as a new class of antibacterial and antifungal drugs. Further biomedical research is required to make 4H-1,4-benzothiazines related compounds as potential antibacterial and antifungal drugs.